ACE Biology for NEET/ AIPMT/ AIIMS Medical Entrance Exam Vol. 1 (class 11) 9385846841, 9789385846847

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DISHA PUBLICATION

© Copyright Authors & Publisher

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No part of this publication may be reproduced in any form without prior permission of the author and publisher. The

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author and the publisher do not take any legal responsibility for any errors or misrepresentations that might have crept

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in. We have tried and made our best efforts to provide accurate up-to-date information in this book.

For further information about the books from DISHA publIcAtIon, Log on to www.dishapublication.com or email to [email protected]

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Preface We feel great pleasure in introducing the book, ‘ACE Biology for AIPMT/NEET Entrance Exam Vol- I’. The book is essentially examination oriented with an object to lighten the burden of the students.

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The salient features of the book are as follows:  The book has been written according to the Latest syllabus of AIPMT/NEET issued by MCI (2015)  Each chapter begins with a title cover having major information of the content in ‘At a glance’  The photographs and complicated figures have been made simple and ‘hand-drawn’.  A number of ‘Connecting concepts’ have been added. They have also been made more purposeful and self explanatory

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 The key terms throughout the text have been printed in bold to draw more attention.  The MCQs of various national and state level entrance examination are up to date (2015)  In ‘Check points’ an attempt has been made to make the revision by the student more meaningful, which will help them to retain the matter for a longer duration. Since, there have been changes in syllabus of NCERT and AIPMT from time to time, certain topics, like ‘Biomedical Engineering’, ‘Growth and Regeneration’ and ‘Biology of Living World’ have been dropped from the book. Besides, the content of certain other chapters have been modified to make them more AIPMT oriented.

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Looking at the pattern of AIPMT, the authors have also added a new set of questions, ‘NCERT- BASED QUESTIONS’, after each and every chapter of the book. The students will find it very useful for the competitive exams.

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 The total look of the book has been kept very friendly to the students and more attractive to the teachers.

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 Besides, the following are the major highlights of the book :

Around 5000 questions in the ‘Window to Competitive Exams’ covering exams like AIPMT, AIIMS, AFMC, BHU, AMU, CPMT, JIPMER, Vellore, Wardha, DPMT, Kerala PMT, K-Cet etc.

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More than 1000 questions are covered under NCERT-Based QUESTIoNS.

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The questions that have become out dated, i.e., before 1995, have been dropped.

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(iv) Most of the topics not covered in AIPMT and other PMTS have been removed.

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(iii) The printing and other type of errors have been specially taken care of.

Though attempt has been made to make the book error-free but shortcomings are inevitable. We shall be grateful to readers for pointing out and suggesting ways for the improvement of the book

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As always, we are grateful to Dr. O.P. Agarwal and the entire team of ‘Disha Publication’, to whose behest these editions have finally seen the light. The members of Disha team cooperated with boundless enthusiasm and limitless energy. It was a pleasing experience to work with them.

Authors

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We express our sincere appreciations to all students and faculty members for their help in the improvement of this book.

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CONSULT THE AUTHOR Dr. R.C. Narang M.Sc. (Gold medalist), Ph.D.

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M.M. (P.G.) College, Modinagar (UP) In case of any confusion regarding any question/ explanation given in the book you can contact the authors, at [email protected] or [email protected] or put your query at aipmtbiology.com

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contents AIPMT 2016 Solved Paper

1

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V1-1-7

The Living World & Taxonomy

Chapter

1-34

•  Living and non livings •  Basic characteristics of livings •  Biological Organization •  Important Achievements Made By Scientists Biologists Upto 19th Century •  Important Achievements Made By Scientists Biologists In 20th Century •  Important Achievements Made By Scientists/Biologists In 21st Century •  Biological Study and its Important Branches •  Scope of Biology •  Myths, Disbeliefs or Misconceptions in Biology and their Reality •  Misuse of Biology •  Types of Species •  History of classification •  Basic categories of hierarchy •  Taxonomic Aids

Biological Classification

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35-72

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Plant Kingdom

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•  Monera (Kingdom of Prokaryotes) •  Protista (Kingdom of Unicellular Eukaryotes) •  Protozoa •  Fungi (Kingdom of Multicellular Decomposers) •  Plantae (Kingdom of Plants) •  Animalia (Kingdom of Animals) •  Viruses •  Viroids •  Lichens

73-110

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•  Angiosperms (Flowering

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Animal Kingdom (Part-I & II)

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•  Types of Classification •  Classification of Plants •  Algae •  Bryophytes •  Pteridophyta •  Gymnosperms Plants) •  Viroids •  Plant Life Cycle and Alternation of Generation

111-166

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Chapter

Protozoa •  Classification •  Phylum Porifera •  Phylum Cnidaria (Coelenterata) •  Phylum Ctenophora •  Phylum Platyhelminthes •  Phylum Aschelminthes •  Phylum Annelida •  Phylum Arthropoda •  Phylum Mollusca •  Phylum Echinodermata •  Phylum Hemichordata •  Phylum Chordata •  Class Amphibia •  Class Reptilia •  Class Aves •  Class Mammalia

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•  Phylum

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Chapter

Morphology of Flowering Plants 167-218

•  The Root  •  Shoot System  •  Leaf  •  The Inflorescence  •  The Flower  •  The Seed  •  Semitechnical Description of a Typical Flowering Plants  •  Description of fabaceae, solanaceae and liliaceae families

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6

Anatomy of Flowering Plants

Chapter

219-258

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•  The Tissue   •  Meristematic Tissue  •  Permanent Tissues  •  Complex Permanent Tissues  •  Special Tissues  •  The Tissue System  •  Anatomy of Dicotyledonous and Monocotyledonous Plants  •  Dicotyledonous Roots  •  Monocotyledonous Roots  •  Dicotyledonous Stem  •  Monocotyledonous Stem  •  Dorsiventral (Dicotyledonous) Leaf  •  Isobilateral (Monocotyledonous ) Leaf  •  Secondary Growth

7

Chapter

Animal Tissues (Histology) & Cockroach, Earthworm and Frog 259-332

•  I Epithelial Tissue  •  II Connective Tissue  •  III Nervous Tissue  •  Muscular Tissue  •  Organ Histology  •  Integument  •  Body Structure  •  Digestive System  •  Excretory System  •  Blood Vascular System  •  Respiratory System  •  Nervous System  •  Endocrine System  •  Sensory Organs  •  Reproductive System  •  Body and Coelom  •  Locomotion  •  Nutrition  •  Respiration  •  Excretory

Cell : The Unit of Life

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System  •  Blood Vascular System (BVS)  •  Nervous System  •  Reproductive System  •  Endoskeleton

Chapter

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333-380

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Biomolecules : Enzymes, Minerals & Vitamins

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•  Cell Theory  •  An Overview of Cell  •  Prokaryotic Cells  •  Eukaryotic Cells

381-422

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Chapter

Cell Cycle and Cell Division

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•  Carbohydrates  •  Lipids  •  Fatty Acids  •  Proteins  •  Amino Acids  •  Nucleic Acids (DNA & RNA)  •  Enzymes •  Minerals •  Vitamins

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•  Cell Cycle  •  Mitosis and its significance  •  Meiosis and its significance

423-448

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11

Transport in Plants

Chapter

449-490

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•  Means of Transport  •  Plant Water Relation  •  Long Distance Transport of Water  •  Transpiration  •  Main Theories About the Mechanism of closing and opening of stomata  •  Uptake & Transport of Mineral Nutrients  •  Transport in Phloem

12

Mineral Nutrition

Chapter

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491-522

•  Methods to Study the Mineral Requirement of Plants  •  Essential Mineral Elements  •  Mechanism of Absorption of Elements  •  Translocation of Solutes (Mineral Salts)  •  Soil as Reservoir of Essential Elements  •  Metabolism of Nitrogen  •  Types of Nutrition in Plants

13

Photosynthesis

Chapter

523-574

•  Early

Experiments / History of Photosynthesis  •  Site of Photosynthesis  •  Photorespiration  •  Factors Affecting Photosynthesis

14

Photosynthesis  •  Photosynthetic

Pigments  •  Mechanism

of

Respiration in Plants

Chapter

575-616

•  Types of Respiration  •  Aerobic Respiration  •  The Respiratory Balance Sheet  •  Amphibolic Pathway  •  Respiratory Ratio or Respiratory Quotient  •  Hexose Monophosphate Pathway (Hmp)  •  Anaerobic Respiration  •  Factors Affecting Rate of Respiration

15

Plant Growth and Development

Chapter

617-652

•  Growth  •  Growth Rates  •  Differentiation, De-Differentiation Regulators  •  Photoperiodism  •  Vernalization  •  Seed Dormancy

16

and

Re-Differentiation  •  Development  •  Plant

Digestion & Absorption

Chapter

•  Digestive System in Human  •  Absorption of Food

653-674

Growth

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17 Chapter

Breathing and Exchange of Gases

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675-696

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•  Respiratory System in Human  •  Air Volumes  •  Transportation of Gases  •  Important Terms and Disorders of Respiratory System

18

Body Fluids and Circulation

Chapter

697-720

•  Human Heart  •  Blood Pressure  •  Pulse  •  Arteries, Veins and Capillaries  •  Arterial System in Human  •  Venous System in Human  •  Lymphatic System  •  Blood Clotting (Haemostasis)

19 Chapter

Excretory Products and their Elimination

721-744

•  Excretory Structures in Non-Chordates  •  Excretory Structures in Vertebrates  •  Excretory System in Human  •  Urine Formation  •  Accessory Excretory Structures  •  Disorders of Excretory System

20

Locomotion and Movement

Chapter

745-774

•  Structure of Bicep (Skeletal) Muscle  •  Muscle Contraction  •  Human Endoskeleton  •  Joints  •  Bones Disorders

21 Chapter

Neural Control & Coordination (Part-I & II)

775-818

•  Conduction of Nerve Impulse  •  Central Nervous System (Cns)  •  Human Brain  •  Peripheral Nervous System (Pns)  •  Reflex Action  •  Autonomous Nervous System (Ans)  •  Human Eye  •  Human Ear  •  Tongue  •  Nose  •  Other Sensory Structures

22 Chapter

Chemical Coordination & Integration

•  Parahormones/ Local Hormones  •  Endocrine Glands  •  Hormonal Action

819-852

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AIPMT 2016 SOLVED PAPER 1. 2. 3.

The coconut water from tender coconut represents (1) endocarp (2) fleshy mesocarp (3) free nuclear proembryo (4) free nuclear endosperm Which of the following statements is wrong for viroids? (1) They lack a protein coat (2) They are smaller than viruses (3) They cause infections (4) Their RNA is of high molecular weight Which of the following features is not present in the Phylum - Arthropoda ? (1) Chitinous exoskeleton (2) Metameric segmentation (3) Parapodia (4) Jointed appendages 4. Emerson’s enhancement effect and Red drop have been instrumental in the discovery of (1) photophosphorylation and non-cyclic electron transport (2) two photosystems operating simultaneously (3) photophosphorylation and cyclic electron transport (4) oxidative phosphorylation 5. In which of the following, all three are macronutrients? (1) Boron, zinc, manganese (2) Iron, copper, molybdenum (3) Molybdenum, magnesium, manganese (4) Nitrogen, nickel, phosphorus 6. Mitochondria and chloroplast are (a) semi-autonomous organelles (b) formed by division of pre-existing organelles and they contain DNA but lack protein synthesizing machinery Which one of the following options is correct ? (1) Both (a) and (b) are correct (2) (b) is true but (a) is false (3) (a) is true but (b) is false (4) Both (a) and (b) are false 7. In a chloroplast the highest number of protons are found in (1) stroma (2) lumen of thylakoids (3) inter membrane space (4) antennae complex 8. Photosensitive compound in human eye is made up of (1) Guanosine and Retinol (2) Opsin and Retinal (3) Opsin and Retinol (4) Transducin and Retinene

9. 10.

Spindle fibres attach on to (1) Telomere of the chromosome (2) Kinetochore of the chromosome (3) Centromere of the chromosome (4) Kinetosome of the chromosome Which of the following pairs of hormones are not antagonistic (having opposite effects) to each other? (1) Parathormone – Calcitonin (2) Insulin – Glucagon (3) Aldosterone – Atrial Natriuretic Factor (4) Relaxin – Inhibin 11. Microtubules are the constituents of 12. 13. 14. 15. 16. 17.

(1) Cilia, Flagella and Peroxisomes (2) Spindle fibres, Centrioles and Cilia (3) Centrioles, Spindle fibres and Chromatin (4) Centrosome, Nucleosome and Centrioles The Avena curvature is used for bioassay of : (1) ABA (2) GA3 (3) IAA (4) Ethylene The standard petal of a papilionaceous corolla is also called (1) Carina (2) Pappus (3) Vexillum (4) Corona Tricarpellary syncarpous gynoecium is found in flowers of (1) Liliaceae (2) Solanaceae (3) Fabaceae (4) Poaceae One of the major components of cell wall of most fungi is (1) Chitin (2) Peptidoglycan (3) Cellulose (4) Hemicellulose In meiosis crossing over is initiated at (1) Pachytene (2) Leptotene (3) Zygotene (4) Diplotene Which of the following is a characteristic feature of cropland ecosystem ? (1) Absence of soil organisms (2) Least genetic diversity (3) Absence of weeds (4) Ecological succession 18. Changes in GnRH pulse frequency in females is controlled by circulating levels of (1) estrogen and progesterone (2) estrogen and inhibin (3) progesterone only (4) progesterone and inhibin

V1-2

19. Which of the following features is not present in Periplaneta americana ? (1) Schizocoelom as body cavity (2) Indeterminate and radial cleavage during embryonic development (3) Exoskeleton composed of N-acetylglucosamine (4) Metamerically segmented body 20. Which one of the following statements is wrong ? (1) Cyanobacteria are also called blue-green algae (2) Golden algae are also called desmids (3) Eubacteria are also called false bacteria (4) Phycomycetes are also called algal fungi 21. Proximal end of the filament of stamen is attached to the (1) Anther (2) Connective (3) Placenta (4) Thalamus or petal 22. Which one of the following cell organelles is enclosed by a single membrane ? (1) Mitochondria (2) Chloroplasts (3) Lysosomes (4) Nuclei 23. Lack of relaxation between successive stimuli in sustained muscle contraction is known as (1) Spasm (2) Fatigue (3) Tetanus (4) Tonus 24. Which of the following is not a stem modification? (1) Pitcher of Nepenthes (2) Thorns of citrus (3) Tendrils of cucumber (4) Flattened structures of Opuntia 25. Water soluble pigments found in plant cell vacuoles are (1) Xanthophylls (2) Chlorophylls (3) Carotenoids (4) Anthocyanins 26. Select the correct statement : (1) Gymnosp erms are b oth homosp orous and heterosporous (2) Salvinia, Ginkgo and Pinus all are gymnosperms (3) Sequoia is one of the tallest trees (4) The leaves of gymnosperms are not well adapted to extremes of climate 27. Which type of tissue correctly matches with its location ? Tissue Location (1) Smooth muscle Wall of intestine (2) Areolar tissue Tendons (3) Transitional epithelium Tip nose (4) Cuboidal epithelium Lining of stomach 28. A plant in your garden avoids photorespiratory losses, has improved water use efficiency shows high rates of photosynthesis at high temperatures and has improved efficiency of nitrogen utilisation. In which of the following physiological groups would you assign this plant ? (1) C3 (2) C4 (3) CAM (4) Nitrogen fixer

BIOLOGY 29. Which of the following characteristic features always holds true for the corresponding group of animals? (1) (2) (3) (4)

Cartilaginous endoskeleton Viviparous Possess a mouth with an upper and a lower jaw 3 - chambered heart with one incompletely divided ventricle

Chondrichthyes Mammalia Chordata Reptilia

30. The amino acid Tryptophan is the precursor for the synthesis of (1) Melatonin and Serotonin (2) Thyroxine and Triiodothyronine (3) Estrogen and Progesterone (4) Cortisol and Cortisone 31. Reduction in pH of blood will (1) reduce the rate of heart beat. (2) reduce the blood supply to the brain. (3) decrease the affinity of hemoglobin with oxygen. (4) release bicarbonate ions by the liver. 32. Which one of the following statements is wrong ? (1) Sucrose is a disaccharide. (2) Cellulose is a polysaccharide. (3) Uracil is a pyrimidine. (4) Glycine is a sulphur containing amino acid. 33. In bryophytes and pteridophytes, transport of male gametes requires (1) Wind (2) Insects (3) Birds (4) Water 34. Which one of the following statements is not true? (1) Tapetum helps in the dehiscence of anther (2) Exine of pollen grains is made up of sporopollenin (3) Pollen grains of many species cause severe allergies (4) Stored pollen in liquid nitrogen can be used in the crop breeding programmes 35. Which one of the following characteristics is not shared by birds and mammals ? (1) Ossified endoskeleton (2) Breathing using lungs (3) Viviparity (4) Warm blooded nature 36. Nomenclature is governed by certain universal rules. Which one of the following is contrary to the rules of nomenclature? (1) Biological names can be written in any language (2) The first word in a biological name represents the genus name, and the second is a specific epithet (3) The names are written in Latin and are italicised (4) When written by hand, the names are to be underlined

AIPMT 2016 SOLVED PAPER 37. 38. 39. 40.

Blood pressure in the pulmonary artery is (1) same as that in the aorta. (2) more than that in the carotid. (3) more than that in the pulmonary vein. (4) less than that in the venae cavae. Cotyledon of maize grain is called (1) plumule (2) coleorhiza (3) coleoptile (4) scutellum In the stomach, gastric acid is secreted by the (1) gastrin secreting cells (2) parietal cells (3) peptic cells (4) acidic cells Chrysophytes, Euglenoids, Dinoflagellates and Slime moulds are included in the kingdom (1) Monera (2) Protista (3) Fungi (4) Animalia 41. Water vapour comes out from the plant leaf through the stomatal opening. Through the same stomatal opening carbon dioxide diffuses into the plant during photosynthesis. Reason out the above statements using one of following options (1) Both processes cannot happen simultaneously. (2) Both processes can happen together because the diffusion coefficient of water and CO2 is different. (3) The above processes happen only during night time. (4) One process occurs during day time, and the other at night. 42. In mammals, which blood vessel would normally carry largest amount of urea ? (1) Renal Vein (2) Dorsal Aorta (3) Hepatic Vein (4) Hepatic Portal Vein 43. Which of the following is not a characteristic feature during mitosis in somatic cells ? (1) Spindle fibres (2) Disappearance of nucleolus (3) Chromosome movement (4) Synapsis

V1-3

44. Which of the following statements is not correct ? (1) Pollen grains of many species can germinate on the stigma of a flower, but only one pollen tube of the same species grows into the style. (2) Insects that consume pollen or nectar without bringing about pollination are called pollen/nectar robbers. (3) Pollen germination and pollen tube growth are regulated by chemical components of pollen interacting with those of the pistil. (4) Some reptiles have also been reported as pollinators in some plant species. 45. Specialised epidermal cells surrounding the guard cells are called (1) Complementary cells (2) Subsidiary cells (3) Bulliform cells (4) Lenticels 46. Which of the following guards the opening of hepatopancreatic duct into the duodenum ? (1) Semilunar valve (2) Ileocaecal valve (3) Pyloric sphincter (4) Sphincter of Oddi 47. Stems modified into flat green organs performing the functions of leaves are known as (1) Cladodes (2) Phyllodes (3) Phylloclades (4) Scales 48. A cell at telophase stage is observed by a student in a plant brought from the field. He tells his teacher that this cell is not like other cells at telophase stage. There is no formation of cell plate and thus the cell is containing more number of chromosomes as compared to other dividing cells. This would result in (1) Aneuploidy (2) Polyploidy (3) Somaclonal variation (4) Polyteny 49. A typical fat molecule is made up of (1) three glycerol molecules and one fatty acid molecule (2) one glycerol and three fatty acid molecules (3) one glycerol and one fatty acid molecule (4) three glycerol and three fatty acid molecules

V1-4

BIOLOGY

HINTS & SOLUTIONS 1. (4) Coconut water is the clear liquid inside young green coconuts (fruits of the coconut palm). In early development, it serves as a suspension for the endosperm of the coconut during the nuclear phase of development. As growth continues, the endosperm matures into its cellular phase and deposits into the rind of the coconut meat. 2. (4) Viroids, the smallest known pathogens, are naked, circular, single-stranded RNA molecules that do not encode protein yet replicate autonomously when introduced into host plants. Viroids only infect plants; some cause economically important diseases of crop plants, while others appear to be benign. 3. (3) All arthropods possess a stiff exoskeleton (external skeleton) composed primarily of chitin. Arthropod bodies are divided into segments. Parapodia are paired, lateral appendages extending from the body segments. Arthropod appendages may be either biramous (branched) or uniramous (unbranched). They do not possess jointed appendages. 4. (2) Wavelengths beyond 700nm are apparently of insufficient energy to drive any part of photosynthesis. So a huge drop in efficiency has been noticed at 700nm. This phenomenon is called as "Red drop effect". In other words there is a sharp decrease in quantum yield at wavelengths greater than 680nm. The number of oxygen molecules released per light quanta absorbed is called as quantum yield of photosynthesis. This effect was first of all noticed by Robert Emerson. Later on Emerson and his group observed that if chlorella plants are given the inefficient far red light and red light of shorter wavelengths in alternate fashion, the quantum yields were greater than could be expected from adding the rates found when either color was provided alone. This synergistic effect or enhancement is known as EEE or "Emerson Enhancement Effect". This was the first good evidence that there are two photo systems; one absorbs far red light and other red light and both of them must operate to drive photosynthesis most effectively. 5. (Bonus) Nitrogen, phosphorus, potassium, calcium, sulfur and magnesium are the macronutrients. In the above given options no three element denotes macronutrients.

6. (3) Mitochondria & chloroplast are semi-autonomous cell organelle which are formed by division of pre-existing organelle & contain DNA but they also contain protein synthesizing machinery, thus (a) is true & (b) is false. 7. (2) Proton concentration is higher in the lumen of thylakoid due to photolysis of water, H+ pumping and NADP reductase activity in stroma. During the lightdependent reaction, protons are pumped across the thylakoid membrane into the lumen making it acidic down to pH 4. 8. (2) Retinal is also known as retinaldehyde. It was originally called retinene, and renamed afterwards it was discovered to be vitamin A aldehyde. Retinal is one of the many forms of vitamin A (the number of which varies from species to species). Retinal is a polyene chromophore, bound to proteins called opsins, and is the chemical basis of animal vision. 9. (2) Attachment of microtubules to chromosomes is mediated by kinetochores, which actively monitor spindle formation and prevent premature anaphase onset during mitosis. 10. (4) Calcitonin exerts its effects by interacting with target cells, primarily in bone and kidney. The actions of PTH and calcitonin are antagonistic on bone resorption but synergistic on decreasing the renal tubular reabsorption of phosphorus. Insulin and glucagon work synergistically to keep blood glucose concentrations normal. An elevated blood glucose concentration results in the secretion of insulin and glucose is transported into body cells. Aldosterone secretion may be inhibited by potassium depletion, inhibitors of the renin-angiotensin system, dopamine and atrial natriuretic factor. The latter appears to be an important physiological regulator of aldosterone secretion. ANF inhibits basal, ACTH, Angiotensin II and potassium-stimulated aldosterone production in vitro by a direct action on the adrenal gland. Inhibin is a hormone secreted by granulosa cells of the ovary which inhibit the secretion of FSH (Follicle Stimulating Hormone) whereas relaxin produced by ovary and placenta at the time of childbirth to softens the ligament in the pelvis and widens the cervix.

AIPMT 2016 SOLVED PAPER

V1-5

11. (2) Microtubules are long, hollow cylinders made up of polymerised  - and  -tubulin dimers. Microtubules are part of a structural network (the cytoskeleton) within the cell's cytoplasm. Roles of the microtubule cytoskeleton include mechanical support, organization of the cytoplasm, transport, motility and chromosome segregation so they are present in cilia and flagella for cellular movement, centrioles for chromosomal movement and spindle fibres for structural organization as well as chromosomal movement during nuclear division.

18. (1) At the pituitary, GnRH stimulates the synthesis and secretion of the gonadotropins, follicle-stimulating hormone (FSH), and luteinizing hormone (LH). These processes are controlled by the size and frequency of GnRH pulses, as well as by feedback from progesterone and estrogens. Low-frequency GnRH pulses are required for FSH release, whereas high-frequency GnRH pulses stimulate LH pulses in a one to one manner.

12. (3) Auxin has been clearly demonstrated in the leaf sheath or coleoptile of oat plant (Avena sativa). This plant coleoptile has been used for the test of hormone Auxin (IAA) participating in the growth of the plant.

20. (3) Eubacteria are the True bacteria.

13. (3) Papilionaceous flowers are flowers with the characteristic irregular and butterfly-like corolla. A single, large upper petal is known as the banner or vexillum and the name has been derived from an ancient military standard. 14. (1) The Liliaceae are a huge variety, comprising about 280 genera and 4000 species of perennial herbs mostly. It includes starchy rhizomes, corms or bulbs, characterized by alternate leaves which are whorled. The flowers are often showy, mostly bisexual and actinomorphic. Also, they exhibit tricarpellary syncarpous gynoecium. Example of such a class is the Erythronium montanum, the alpine fawn lily. 15. (1) A cell wall is a rigid structural layer, which provides protection and structural support to the cells. The composition of cell walls varies from species to genera. In the case of fungi, the cell wall is composed of strong covalent linkages of chitin, glucans and glycoproteins. Alternatively, in case of land plants, the cell wall is composed of cellulose and hemicellulose and Archean cell walls have peptidoglycans. 16. (1) Meiosis is a process (discovered by German biologist, Oscar Hertwig) where a single cell divides twice to produce four cells containing half the original amount of genetic information. These cells are our sex cells sperm in males, eggs in females. Crossing over is the process by which two chromosomes, exchange some distal part of their DNA. This process occurs in the Pachytene stage of Prophase I of meiosis. 17. (2) Cropland ecosystem is largest anthropogenic ecosystem characterized by less diversity and high productivity.

19. (2) Periplanata americana shows spiral and determinate types of cleavage during embryonic development which is a feature of Protostomes. 21. (4) The proximal end is attached to the thalamus whereas the distal end bears anther. 22. (3) Double Membrane bound Organelles: Mitochondria, Chloroplasts, Endoplasmic Reticulum, Golgi Body, and Nucleus. Single Membrane bound Organelles: Lysosomes, Peroxisomes, and Vacuoles. Organelles lacking any membrane: Ribosomes, Centrioles, Nucleolus. 23. (3) Sustained contraction with no relaxation phase is called muscle tetanus. 24. (1) Pitcher of Nepenthes or pitcher plant is modification of leaf whereas thorns in citrus tendrils of cucumber and flattened structure of Opuntia are all stem modification. 25. (4) Many leaves produce water-soluble vacuolar pigments, which are stored within cell vacuoles (microscopic water sacs within each cell). Two major classes of leaf vacuolar pigments are anthocyanins and betalains. 26. (3) Sequoia semepervirans is one of tallest trees. 27. (1) Wall of intestine is made of smooth muscle. Tendons consist of dense regular connective tissue fascicles encased in dense irregular connective tissue sheaths. Tip of nose consists of squamous epithelium. Lining of epithelium is made of columnar epithelium. 28. (2) C4 plants are adapted to hot and dry climate and lack photorespiration due to Kranz anatomy and have Greater productivity of biomass. 29. (1) C hondr icht hyes a lways have car t i lag inous endoskeleton. Most mammals are viviparous, giving birth to live young. However, the five species of monotreme, the platypuses and the echidnas, lay eggs. Chordates have jawless animals (Agnatha) as well. Most reptiles have 3 chambered heart. Crocodilians have 4 chambered hearts. Turtles have 3 chambered heart but with an incomplete wall in the single ventricle, so their hearts are functionally 4 chambered.

V1-6

oxyntic cells) in the gastric glands in the stomach. 40.

and slime mould are included in Protista. 41.

(4) Bryophytes have neither pollen nor flowers and rely on water to carry the male gametes (the sperm) to the female gametes (the eggs). The antherozoids (male gametes of pteridophytes) are armed with hair-like or whip-like cilia or flagellae and are able to swim through water; they do not travel great distances and are only released when free water is available.

evaporating from the surface of leaf cells through stomatal opening exposed to air. This is called transpiration. Through the same stomatal opening carbon dioxide diffuses into the plant during photosynthesis. Simultaneously as both are the process of simple diffusion occurs in order of diffusion pressure

other waste materials and then it pours it all in the

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right ventricle of the heart for oxygenation. The heart distributes the blood to various parts of the body from here. So the impure blood brought by the Hepatic Vein and other blood vessels get distributed through

(4) Synapsis is the pairing of two homologous chromosomes

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homologous pairs prior to their segregation, and

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(3) Giving birth to living young that develop within the mother's body rather than hatching from eggs. All mammals except the monotremes are viviparous.

possible chromosomal crossover between them. Synapsis takes place during prophase I, Zygotene of meiosis. 44.

(3) Arteries have higher blood pressure than vein because blood is forced inside them from heart and also their lumen is narrow. (4) The cotyledons are known as seed leaves, they are attached to the embryonic axis. Dicotyledons typically have two cotyledons and monocotyledons have only one cotyledon. The single shield-shaped cotyledon in grains known as scutellum.

(1) Pollen grains of different species are incompatible, so they fail to germinate. If the pollen-stigma interaction

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(1) Binomial nomenclature (also called binominal nomenclature or binary nomenclature) is a formal system of naming species of living things by giving each a name composed of two parts, both of which use Latin grammatical forms, although they can be based on words from other languages.

Hepatic Vein. that occurs during meiosis. It allows matching-up of

(1) Tapetum is important for the nutrition and development of pollen grains, as well as a source of precursors for the pollen coat.

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the aorta. This will automatically imply that the Renal

43.

is compatible, the pollen grain hydrates and germinates shortly following landing on the stigma. 45.

(2) Specialized epidermal cells surrounding the guard cells are known as Subsidiary or accessory cell.

46.

(4) The sphincter of Oddi (or hepatopancreatic sphincter) is a muscular valve that controls the flow of digestive juices (bile and pancreatic juice) through the ampulla

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(4) Glycine (abbreviated as Gly or G) is the smallest of the 20 amino acids commonly found in proteins, and indeed is the smallest possible (having a hydrogen substituent as its side-chain). The formula is NH2CH2COOH. Its codons are GGU, GGC, GGA, GGG of the genetic code.

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(2) All unicellular eukaryotic organism like diatoms, desmids (chrysophytes), euglenoids, dinoflagellates

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(3) Reduction of pH of blood will decrease the affinity of hemoglobin with oxygen which in turn causes Acidosis.

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(1) Tryptophan is a precursor to neuro-transmitters serotonin and melatonin. Thyroxine (3,5,3',5'-tetraiodothyronine) is produced by follicular cells of the thyroid gland. It is produced as the precursor thyroglobulin. Estrogen is biosynthesized from progesterone (arrived at in two steps from cholesterol, via intermediate pregnenolone). Cortisone is one of several end-products of a process called steroidogenesis. Cortisol is produced in the adrenal cortex of kidney.

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30.

BIOLOGY

of Vater into the second part of the duodenum. 47.

(3) Phylloclade to refer a portion of a flattened leaf-like stem or branch with multiple nodes and internodes, and cladode for a single internode of a phylloclade. In some plants, the petioles are flattened and widened, to become phyllodes or phyllodia.

AIPMT 2016 SOLVED PAPER 48. (2) This phenomenon is known as Polyploidy, wherein the cells contain more than two paired (homologous) sets of chromosomes. Polyploidy is often seen in the case of plants. The major cause of polyploidy is the non - disjunction of sister chromatids during meiotic recombination. This condition is actually useful in development of new crop varieties.

V1-7

49. (2) Fat molecules are made of atoms of carbon, hydrogen and oxygen. The hydrogen and oxygen atoms binds to the carbon, as pictorially depicted. A typical fat molecule has one glycerol and three fatty acid molecules.

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Chapter

1

The Living World & Taxonomy Part-I : The Living World

At a Glance

2. 4.

Theory of Germ plasm Germ theory of diseases

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Biologists – 1. Alexander Flemming 3. N E Borlaug 5. Ian Wilmut 7. Carolus Linnaeus

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Books – 1. Philosophie Zoologique 3. Systema Naturae

Living and non livings



Important achievements made by scientists /biologists in 20th century

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Apiculture and sericulture Anabolism and Catabolism Ectotherms and Endo therms

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Differences – 1. Livings and Non-livings 2. 3. Biomedical engineering & genetic engineering 4. 5. Bioinformatics and computer simulation 6. 7. Homeostasis and Haemostasis

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Amniocentesis Genome Serendipity

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Theories – 1. Theory of Pangenesis 3. Cell theory 5. Theory of natural selection

2. 4. 6.

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Terms and definitions – 1. Bioterrorism 3. Pasteurization 5. Palaeontology

  

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While going through the chapter pay special attention to the following-

2. 4.

Micrographia Origin of Species

2. 4. 6. 8.

Watson and Crick William Harvey H G Khorana Stanley Cohen

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There is no clear cut distinction between living and non-living things. The organisms like viruses are non-living by themselves but become active and multiply when they are inside the living cells. They are neither plants nor animals but have hereditary material of their own. The prions do not even have the hereditary material and propagate diseases like Kuru and Madcow. The living organisms occur almost in every habitat on earth. We can find them from cold mountains to hot springs. A wide range of the living organisms can be found in fresh or marine water bodies and forests. The living froms as compared to non-livings have some fundamental characteristics. They are defined as ‘the self-replicating, self evolving with self-regulating interactive systems capable of responding to external stimuli’. All living organisms- the past, the present and the future, are linked to one another by sharing the common genetic material.

             

Basic characteristics of livings Achievements made by scientists /biologists upto 19th century

Important achievements made by scientists /biologists in 21st century Biological study and its important branches Scope of Biology

Myths, disbeliefs or misconceptions in biology and their reality Misuse of Biology

Careers in Biology Types of species

Important terms

History of classi�ication

Basic categories of hierarchy Concept of species

Types of classi�ication

Codes of nomenclature Taxonomic aids

2

BIOLOGY Following are the important distinctive characteristics exhibited by living forms.

1. Growth : The increase in mass and increase in the number of individuals are twin characteristics of growth. The multi-cellular organisms grow by cell division. The animals grow up to a certain age, whereas the plants grow throughout their life. The cell devision also occurs to replace lost cells. The unicellular organisms also grow by cell division but there it is a type of reproduction. In multicellular organisms, whether animals or plants, the growth and reproduction are mutually exclusive events. Though the non-livings, like mountains, sand mounds and snow also grow, if we consider the increase in body mass as criterion, but this growth is by accumulation of material on the surface, and not from inside as we see in animals. So, growth alone cannot be considered as a defining property of living organisms until and unless it is well specified.

2. Reproduction : The living organisms reproduce asexually as well as sexually to multiply their number. Fungi reproduce asexually by spore formation. The lower organisms, like Hydra and Yeast, reproduce by budding. In Planaria (flat worm), there is fragmentation and regeneration of lost parts. In unicellular forms, as described above, the reproduction is synonymous with growth. Moreover, there are living organisms who do not reproduce, e.g., mule, worker honey bee or infertile human. Thus, the reproduction, like growth, can also not be taken as defining characteristic of the living forms. On the other hand, this is however true, that non-living objects are not capable of reproducing or replicating themselves.

(a)

(b)

Fig. 1.1 (a) Budding in Hydra; (b) Fragmentation in Planaria

3. Metabolism : All living organisms are constantly making or breaking biomolecules. Such conversions are due to chemical reactions, and sum total of all such chemical reactions, occurring in the body is called metabolism. The metabolic reactions can be anabolic (constructive) or catabolic (destructive). In Catabolism the energy is released by the break down of complex material into simpler ones. In cellular respiration, the breaking down of glucose into carbon-di-oxide and water to release energy, is an example of catabolism. In Anabolism the complex material is synthesized from simpler ones. The photosynthesis, in which glucose/starch is synthesized from carbon-di-oxide and water, is an example of anabolism. Each metabolic pathway in the cell is tightly regulated by enzymes (both activators and inhibitors) The non-living objects do not exbibit metabolism. The isolated metabolic reactions in vitro do not make the things living.

THE LIVING WORLD & TAXONOMY

3

4. Consciousness : All the living organisms can sense their surroundings and respond to these environmental stimuli. The stimuli can be physical, chemical or biological. From lower to higher organisms there are various types of sensory structures. The photoperiod affects the seasonal breeders, both plants and animals. All organisms are conscious or aware of their surroundings. Human is the only organism who is aware of himself also, and thus has ‘self-consciousness’ Such selfconsciousness is lacking in patients who are lying in ‘coma’ and are brain-dead.

5. Cellular organization : All organisms, from prokaryotes to the most complex eukaryotes have cellular organization. The cell may be simple or highly specialized for the required function. Such cellular organization is not exhibited by non-living objects. Hence, the cellular organization of the body is the defining feature of all living forrms. There is great diversity (biodiversity) in the number and types / variety of organisms present on earth.

6. Homeostasis : It is the maintenance of constancy in the internal conditions (steady state), different from the environment. All organisms maintain within narrow limits the levels of salts, glucose, carbon-di-oxide, oxygen, calcium etc. in the intercellular matrix.

Connecting Concepts  Homeostasis is different from Haemostasis. In Haemostasis the blood flow stops either due to clotting, or by constriction of blood vessels, or by other means.

Homeostasis is the fundamental property of living beings. Most of the lower vertebrates (fishes, amphibians and reptiles) lose most of their heat energy to their environment. These vertebrates are called Ectotherms. These animals depend on the their environment for temperature regulation. At low temperature in the surrounding, their body temperature is also dropped and they become cold. Such animals are, therefore, also called as Cold-blooded animals or Poikilotherms. The higher vertebrates, i.e. birds and mammals, have developed special devices to retard the heat loss to the environment. Their body temperature remains nearly constant and generally higher than the surroundings. Such animals are called Warm- blooded animals or Homeotherms. Since these animals retain thermal energy in the body, they are also known as Endotherms. In mammals when the surrounding temperature is low the peripheral blood vessels constrict to prevent heat loss, and the blood is diverted to the deeper parts of the body. When the ambient (surrounding) temperature is higher, the superficial blood vessels dilate and a part of heat is lost by radiation. We have sensory receptors (modified dendrites of neurons) which perceive coldness (Krause end bulbs) and hotness (End bulbs of Ruffini). The information from such receptors reach hypothalamus, the thermoregulatory centre of the brain. The body temperature can be decreased by vasodilatation of superficial blood vessels, and by sweating. The body temperature can be increased by vasoconstriction of superficial blood vessels and by Shivering (Contraction of skeletal muscles). Since the change in body temperature is in reverse direction or to the negative side of the ambient temperature; such a control system is called Negative Feed Back Loop.

7. Adaptations : Adaptations are the results of natural selection and make the organisms better suited to their environment. The adaptations may be structural, physiological or behavioural.

Connecting Concepts  Few fishes, e.g. Tuna fish and Sword fish, have insulating devices to prevent heat loss. They retain heat energy in the body. Such fishes, unlike others, are endotherms.

4

BIOLOGY Check Point

1. Fill in the blanks with suitable words: (a) ................ is known as the Darwin of 20th century. (b) In unicellular organisms the ................ is synonymous with growth. (c) The sum of all chemical reactions occurring in our body is called ................ . (d) ................ is the only organism that is aware of one self. (e) The number of species that are known and described ranges between ................ . (f) ................ occurs in both living and non-livings, but in living it is from inside. (g) The poikilotherms are also known as ................ animals. (h) Tuna fish, though cold blooded, is ................ . (i) A group of interbreeding individuals is called ................ . (j) ................ is known as the father of zoology.

•

Birds use wings for flight – Volant adaptations.

•

Spiders design web for trapping the flying insects, i.e. their prey.

•

Night blooming flowers are white and emit scent for attracting pollinating insects.

•

Some desert plants are leafless and are adapted for conservation of moisture ( water).

•

Humming birds have extremely narrow and long beak and while hovering, suck the nectar of such flowers which do not have landing platforms.

•

Certain species of orchids resemble in shape, colour and odour of females of certain bees and flies. Such male bees or flies mistakenly attempt to copulate with orchids, and in the attempt transfer the pollen grains from one flower to the other.

Adaptation can be short-term and long-term type. I. Short Term Adaptations - These adaptations persist for shorter duration and completely disappear when the stimulus is removed. •

Darkening of skin when exposed to sun

•

Rosy cheeks in hilly people

•

Turning of shoot towards light

•

Low metabolic rate in animals during hibernation

•

Dormancy in seeds

•

Geotropism in plants

II. Long Term Adaptations - Such adaptations are permanent and persist even in the absence of stimuli. •

Development of beaks, claws and feathers in birds

•

Development of heel in human

•

Use of tail as fifth limb in Kangaroo

•

Opposable thumb in human

•

Scent in night blooming flowers

•

Necessity of mammalian blood protein for egg laying in

Anopheles mosquitoes.

DEATH Organisms reproduce to compensate death or loss of life. When the organisms die, the micro organism decompose the body. The elements which constitute the body are freed and are returned to the ecosystem. Such cycling of elements between living and non-living maintains the balance in nature. Following are the advantages of death: 1.

It avoids over crowding and maintains homeostasis.

2.

It returns minerals to the soil and maintains balance.

3.

The cellular death is essential for making the skin germ-proof.

4.

The cellular death is also essential for the metamorphosis in tadpole.

Stages of Deaths 1.

Clinical death – It is the stoppage of heart beat and breathing process.

2.

Biological death – It is the death of cells and tissues.

The removal of organs, if needed for transplantation, is done after clinical death but before biological death.

THE LIVING WORLD & TAXONOMY

5

BIOLOGICAL ORGANIZATION The biological organization starts with submicroscopic molecular level and ends up in ecosystem and the biosphere. Atom is the lowest unit at molecular level whereas the cell is the lowest unit at organism level. The organization levels, below and above individual level, can be given as : Biosphere

Organism

(Lithosphere+Hydrosphere+Atmosphere)

Visible level Organs

Biome Ecosystem

Tissues

(Interaction between living and non- livings)

Microscopic level Cells

Community (Populations of different species)

Molecules

Species

Sub-microscopic level

(A group of interbreeding individuals)

Atoms

Organism II. Levels of Organization above individual

IMPORTANT ACHIEVEMENTS MADE BY SCIENTISTS BIOLOGISTS UPTO 19TH CENTURY Aristotle (384BC- 322BC) - A Greek philosopher and a student of Plato 

He classified organisms on the basis of complexity in structure and function into a hierarchy, Scala natura, the ladder of life



He wrote Historia Animalium and De Generatione Animalium



He is known as the father of Biology/ Zoology/ Embryology

Andreas Vesalius (1514-1564) – A Belgian scientist. 

He is known as the ‘Father of Anatomy’.



He wrote De Humani Corporis Fabrica (the structure of human body)

William Harvey (1578 -1657) – A British Scientist. 

He discovered blood-circulation. His monograph was named ‘Anatomical Exercise on the motion of the heart and blood’. He is known as the ‘Father of blood circulation’.



He also studied reproduction and development in chick.

Robert Hooke (1635 – 1703 ) – A British Scientist. 

He first coined the term cellulae (cell) in 1665 by observing slice of cork under self made simple microscope.



His book is named ‘Micrographia’

Antony Van Leeuwenhoek ( 1632-1723 ) – A Dutch cloth merchant .- turned into a scientist. 

He invented a simple microscope and studied living cells.



He drew the diagram of bacteria and studied Euglena, sperms, blood corpuscles and compound eyes of insects.

Carolus Linnaeus (1707-1778) - A Swedish Naturalist . 

He published ‘Species Plantarum’ (6000 species of plants) and Systema Naturae( 4000 species of animals ) .in 1758



He also reported Binomial nomenclature, in Philosophia Botanica in 1751, for naming plants and animals.

6

BIOLOGY Georges Leopold Cuvier (1769-1832) - A French Palaeontologist . 

He rejected traditional Scala Naturae of Aristotle.



He studied fossils and laid the foundation of Palaeontology. He is known to be the ‘Father of Modern Palaeontology’.

 He also studied comparative anatomy. Jean Baptiste Lamarck (1744 -1829) - A French Naturalist . 

He was the first to discard the idea of fixity of species.



He is known to be the ‘Father of evolutionary theories’. He wrote Philosophie Zoologique in 1809.

 He introduced the term ‘Biology’ (with Treviranus) Robert Brown (1773-1858) 

He discovered ‘Brownian movement’ in cytoplasm (1828).

 He also discovered ‘Nucleus’ in the cell. Matthias Schleiden (1804-1881) - A German Botanist  He Proposed cell theory in 1838 on the basis of his study on plant tissues. Theodor Schwann (1810-1882) - A German Zoologist .  He strengthened cell theory in 1839 by his study on animal tissues. O. Hertwig (1875) 

He studied fusion of nuclei during fertilization.



He also proposed ‘protoplasmic theory’ to elaborate schultze’s hypothesis that ‘protoplasm is the physical basis of life’.

 He also coined the term ‘cytology’. Charles Robert Darwin (1809 - 1882 ) - A British Naturalist . 

His book ‘The origin of species by means of natural selection’ was published in 1859.



He is called ‘Newton of Biology’.

He proposed the ‘Theory of Pangenesis’ to explain inheritance in the book ‘On the variation of animals and plants under domestication (1868)’ Rudolf C. Virchow (1858) 



He proposed ‘Omnis cellula e cellulae’, i.e., New cells arise from pre-existing cells.

 He also suggested that disease is the pathological condition of cells. Louis Pasteur (1822 - 1895 ) - A French Scientist. 

He proved that fermentation is caused by living organisms (Yeast and Bacteria).



He established ‘Germ theory of diseases’.



He discovered vaccine against Anthrax (caused by Bacillus anthracis in cattle ).



He discarded ‘Spontaneous theory’ of origin of life.

 He also proposed Pasteurization for sterilization ( killing of germs ) Ernst Haeckel 

He introduced 2-kingdoms, ‘Monera’ & ‘Protista’.

 He also coined and fully defined the term ‘Ecology’. Gregor Johann Mendel (1822 - 1884 ) - An Austrian Monk 

He discovered principles of inheritance after his work on Pisum sativum, and published them in 1866.

 Mendel is known to be the ‘Father of genetics’. August Weismann (1834 - 1914 ) - A German Biologist 

He rejected Lamarck’s concept of ‘Inheritance of acquired characters’ and Darwin’s theory of Pangenesis, with the discovery of ‘Theory of Germ plasm’ in 1892.

THE LIVING WORLD & TAXONOMY

IMPORTANT ACHIEVEMENTS MADE BY SCIENTISTS BIOLOGISTS IN 20TH CENTURY Hugo de Vries (1900)- A Dutch Geneticist 

He rediscovered Mendel’s laws with Tschermak (Austrian) and Correns (German) geneticists.



He also proposed the ‘Theory of Mutation’.



Walter Sutton (1904)- An American Geneticist

 He discovered the chromosomal basis of heredity. William Bateson (1909) -A British Biologist  He introduced the term ‘Genetics’ and discovered linkage. T. H. Morgan (1910) -An American Geneticist He discovered sex-linked inheritance and described the phenomenon of linkage and crossing over. Alexander Flemming (1928) -A Scottish Bacteriologist 



Discovered Penicillin, an antibiotic from Penicillium notatum, which contaminated the culture of Staphylococcus bacteria.

 Penicillin was the first antibiotic used in world-war second. Oswald Theodore Avery (1944) - An American Bacteriologist  He discovered that genes are composed of DNA. James Watson (1953) -An American, A Britisher  They discovered double helical and Francis Crick structure of DNA. H.G. Khorana, Robert Holley and Marshall Nirenberg (1968) - A Pakistani, An Americans Khorana synthesized a string of nucleotides in laboratory (First man-man-made gene). The three scientists shared the noble prize for their work on genetic code and protein synthesis. Norman E. Borlaug (1970) - Associated to Green revolution and won Nobel Prize. Stanley Cohen and Herbert Boyer (1973) -American Biochemists 

They discovered recombinant DNA – (rDNA) technology- a break through for modern biotechnology. Ian Willmut and Campbell (1996) – Scottish embryologists 



Produced first live clone of a sheep – ‘Dolly’ Human Genome project was launched in 1990 by US department of energy and National institute of health. In 2001 they identified all the, approximate 25,000 to 30,000 (3 × 104) genes in human DNA consisting of 3-billion (3 × 109) base pairs.

IMPORTANT ACHIEVEMENTS MADE BY SCIENTISTS/ BIOLOGISTS IN 21st CENTURY Paul C. Lauterbur, Sir Peter Mansfield (2003) - First American and second British 

Made discovery concerning MRI

 They were awarded Nobel prize in Physiology or Medicine Barry J. Marshall, J. Robin Warren (2005) - Australians 

Made discovery regarding the role of Helicobacter pylori in Gastritis and Peptic ulcer

 They were awarded Nobel prize in Physiology or Medicine Andrew Z. Fire, Craig C. Mello (2006) - Americans 

They discovered RNA- interference- gene- silencing by RNAds



They were awarded Nobel prize in Physiology or Medicine

7

8

BIOLOGY Harald zur Hausen, Françoise Barré-Sinoussi, Luc Montagnier (2008) - First German, other two French 

Made discovery regarding Human Papilloma Virus and Human Immunodeficiency Virus

 They were awarded Nobel prize in Physiology or Medicine Osamu Shimomura, Martin Chalfie, Roger Y. Tsien (2008) - First Japanese and other two Americans 

Made discovery concerning Green fluorescent Protein

 They were awarded Nobel prize in Chemistry Venkatraman Ramakrishnan, Thomas A. Steitz, Ada E. Yonath (2009) - First Indian, second American and last Israely 

Made studies on structure and functions of ribosomes

 They were awarded Nobel prize in Chemistry Bruce A. Beutler, Jules A. Hoffmann, Ralph M. Steinman (2011) - First American, second Luxembourger and third Canadian 

Made important discovery regarding Innate and Adaptive Immunity



They were awarded Nobel prize in Physiology or Medicine

BIOLOGICAL STUDY AND ITS IMPORTANT BRANCHES 

Biology has been divided into two branches, i.e. Zoology and Botany.



Science of microbiology was created by the invention of microscope in 16th century.



A vast number of animals and plant have been arranged / classified on the basis of evolutionary relationships.



International code of classification are known for animals, plants and bacteria etc.

Aquaculture

It is the production of useful fauna and flora such as algae, fishes, prawn, pearl-oyster etc., at commerical level by utilizing small and large water bodies. Biochemistry It is the study of chemistry of biological processes in the living organisms. It is also known as physiological chemistry or biological chemistry. Biophysics It is application of various tools, techniques, methods and principles of physics for the study of biological processes. Cell Biology It is the study of life processes of cell and their co-relation with the cell structure. It primarily depends on biochemical techniques. Cryopreservation It is preservation of living forms at very low temperature; or effect of (cryobiology) low temperature on living forms. Cytology It is the study of structure and composition of cells. Demography It is statistical study of population dynamics Dysteleology It is study of rudimentary organs Ecology It is the study of relationship of organisms to their physical environment as well as to one another. (a) Auto-ecology – It is the study of individual organisms or single species. (b) Synecology – It is the study of group of organisms. Embryology It is the study of individual development (ontogeny) from egg to hatching/ birth. (‘Developmental Biology’ covers the development upto sexual maturity or adulthood). Entomology It is the study of insects. Ethnology It is study of human races

THE LIVING WORLD & TAXONOMY Ethology Evolutionary Biology Exobiology Fisheries

Genetics Gerontology Histology

Ichthyology Karyology Limnology Marine Biology Molecular biology Morphology Myrmecology Oncology Ophidology (serpentology) Palaeontology Phylogeny Physiology Pisciculture Serology Splanchnology Systematics Taxonomy

9

It is the study of animal behaviour in relation to body functioning, ecology and evolutionary aspects. It is the study of changes in living organism with the passage of time. This field of biology is related to the search of life outside the earth and within the solar system. The rearing, harvesting and marketing the commercially important aquatic fauna. The important fisheries are molluscan fisheries, Crustacean fisheries, sponge fisheries, Esturine fisheries etc. Inland fisheries (in fresh water). It is Study of mechanism of inheritance and maintenance of hereditary characters. It is scientific study of ageing or senescence. Its foundation was laid down by Valdimir Korenchevsky. It is the study of structural organization of living beings at tissue level. The micro technique (Microtomy) used for histology, includes following steps. 1. Fixation of tissue - (To maintain architecture of cells, or to stabilize the proteins.) 2. Dehydration - (Removal of water for preventing decomposition) 3. Paraffin embedding4. Slicing/ sectioning- (Done with the help of microtome) 5. Dewaxing 6. Staining 7. Mounting Biological study of fishes It is the study of cell-nucleus (Karyosome) The study of fresh water bodies (ecosystem) especially lakes. It is the study of Ocean (Marine) animals and plants and their ecological relationship. It is the study of molecular organization (inorganic and organic molecules in the cells) of the organism. The term molecular biology was given for the first time by a British scientist, W.T. Astbury (1898-1961). It is the study of body structure. The internal morphology is also called anatomy. It is scientific study of Ants It is the study of cancer It is study of snakes. (The study of lizards is Saurology) It is the study of fossils which are preserved remains or the traces of organisms that lived in the past, and are now extinct. It is study of evolutionary development, or racial history of a group It is the study of functions of the body systems of animals and plant life, covering vital activities at cellular, tissue and organ level. It is rearing and management of fishes at commercial level It is study of antigen-antibodies and serum It is study of visceral organs (present beneath splanchnic mesoderm) It is the study of diversity and evolutionary relationship of organism based on comparative study of different fields of biology. It is a scientific study of principles and procedures of classification.

(The other branches of biology have been discussed chapter wise with running text)

Check Point 1. Can you differentiate between: (a) Ethology and Ethnology (b) Physiotherapy and Occupational therapy (c) Biotechnology

and

Biomedical

engineering (d) Silviculture and Sericulture (e) Homeostasis and Haemostasis

10

BIOLOGY

SCOPE OF BIOLOGY 

Food storage, cancer, population explosion, poverty, AIDS, and global warming are the burning issues related to human welfare.



Study of medicinal plants has helped in the production of Quinine, Penicillin, Nux vomica, antibiotics etc. for serving the mankind.



Study of classification, life history, vector and diseases has helped in combating human miseries.



With the knowledge of genetics the hereditary diseases and genetic disorder are being minimized.



A number of new courses or specialization, like – Horticulture, Jute technology, Fisheries, Tea Technology, Apiculture, Sericulture. Poultry farming, Aquaculture etc. have emerged. These can be useful in the development of national economy.



Genetically modified (GM) crops are being developed to solve the problem of food shortage.



Direction of bio-technology, conservation of bio-diversity, maintenance of environment and human welfare are in the hands of biologists. Biodiversity, including wild life, is immensely important for human existence.

MYTHS, DISBELIEFS OR MISCONCEPTIONS IN BIOLOGY AND THEIR REALITY Myths/ Misconceptions

Snakes dance at the tune of the flute of snake charmer

Reality/ Fact The prey becomes motionless, perhaps due to fear. They do not have external and middle ear to receive sound.

Snakes visit barns to suck the milk from the teats of cattle

Snakes are carnivores and visit barns for rats only.

Malaria (mal-bad, aria-air) is caused by foul air

Malaria is caused by the species of Plasmodium, and is transmitted by female Anopheles (mosquito). AIDS spreads by direct contact with body fluids.

Snakes can hypnotize or charm their prey

AIDS spreads by sharing food, social kissing or caring

MISUSE OF BIOLOGY 1.

Amniocentesis Amniotic fluid contains foetal-skin cells and amniocytes of amniotic membrane. These cells are cultured for chromosomal study for detecting fetal abnormality. This technique is now being used for sex identification of Embryo/foetus (Between 1½ - 2 ½ months ) , and the fetus is aborted if found to be a female. It is the misuse of a biological technique

2.

Bioweapons It is the development of antibiotic- resistant micro organisms. The spores of Anthrax bacteria ((Bacillus anthracis ) produced and stored to keep them viable for long have been used as a weapon of bioterrorism. The other similar diseases, on epidemic or endemic scale, can be plague and small-pox etc.

THE LIVING WORLD & TAXONOMY

11

CAREERS IN BIOLOGY 1.

Professional Courses

1.

Professional Courses

Name of the Course Anthropology

2.

Vocational Courses

Coverage of the Course It is related to the study of physical, mental, cultural and social development of past and present man

Bioinformatics

It is related to the application of computing systems and computational solution of techniques, analyzing data obtained by experiments, modeling, database searching and instrumentation

to discover biological processes. Biomedical Engineering It deals with the production of spare parts for human, like implants, Biotechnology

artificial limbs, and machines for monitoring the health. It is related to the creation, development and marketing of products through the willful manipulation of life forms on a molecular

Computational biology

level. It is related to application, development and validation of computational hardware and software solutions for building

Computer Simulation

simulation models of biological systems. It converts the physiological phenomena into graphical and

Dairy Technology

multimedia presentation without actually involving organisms. It is related to the improved varieties of cattle, the extraction,

Genetic Engineering

preservation and marketing of the milk and milk-products. It is related to the extraction of selected genes from an organism or synthesizing their copies and inserting them into another

Medical Transcription

completely different organism. It is the course of Interpreting and typewriting (transcribing) dictation from physicians and other healthcare providers regarding

Medicine

patient assessment for diagnostic and therapeutic purposes. It is the science of treating diseases with drugs or chemicals.

Occupational therapy

It deals with the treatment of physically handicapped using physical exercises or vocational training

Pathology

It deals with the diagnosis of pathogens and the diseases by analyzing the chemistry of the body fluid of the affected

Environmental

organisms. It is about assessment of environment, environmental problems

Management

and the conservation of biodiversity for maintaining the balance

Surgery

in nature. It is related to anatomy and physical operations to cure the patients

Veterinary science

suffering from diseases that cannot be cured with medicines. It deals with the health, care and management of domestic animals

12

BIOLOGY 2.

Vocational Courses

Name of the Course Agronomy

Coverage of the Course It is the production and management of crops

Apiculture

It is rearing and maintenance of bees for the production and marketing of honey and wax at the commercial level.

Breeding Biology

It is for the improvement of varieties of plants or animals by

Forensic Science

selective breeding. (It does not manipulate genes). It deals with the application of scientific knowledge, like finger prints, blood typing, and DNA analysis etc., to deal with criminal

Pharmacy

activities and laws. It is related to the production and identification of drugs.

Pharmacology

It is related to the nature, preparation, action and effects of medicines.

Physiotherapy

The study of action of drugs is called Pharmacognosy. It is related to the treatment of defect, disease or weakness by physical remedy as exercises and massage. No drugs are

Poultry farming

administered in physiotherapy. It is the rearing of breeds of poultry birds like domestic fowl, chicken, ducks for eggs and meat etc. at commercial level.

Prawn Farming

It is rearing, transportation and marketing of prawns. It is a part of fisheries.

Sericulture

It is related to the rearing of different strains of silkworms for the production, transportation and marketing of silk at commercial level.

THE LIVING WORLD & TAXONOMY

13

Part-II : Taxonomy While going through the chapter pay special attention to the followingTerms and definitions – 1. Species 3. Allochronic species 5. Taxon 7. Cladogram

2. 4. 6.

Binomial nomenclature Biosystematics Sibling species

Differences – 1. Sympatric and allopatric species 3. Taxonomy and Systematics 5. Phenetics and Cladistics 7. Periodical and Manual

2. 4. 6.

Monotypic and Polytypic species α and β-taxonomy Typological and Biological species

Taxonomists / Biologists – 1. Carolus Linnaeus 3. John Ray

2. 4.

Whittaker Julian Huxley

Books – 1. Historia Animalium 3. Susruta Samhita

2. 4.

Systema Naturae Historia Plantarum

More than 1.2 million animal species, and more than 0.5 million plant species have been identified

Check Point

and described so far

1. Can you differentiate between:

The purpose of biological classification is to name and remember the organisms.

(a) Sibling and sympatric species

Species – It is the basic unit of classification. According to ‘Biological concept of species’, the

(b) Allochronic and synchronic species

species can be defined as a group of natural populations whose members can interbreed among themselves and are reproductively isolated from other such groups. Types of species – 1.

Morphological/ Typological/ Taxonomic species and Biological species Taxonomic species are identified on the basis of morphological characters while biological species are identified on the basis of interbreeding. The term Biological species is not applicable for fossils or asexually reproducing organisms.

2.

Static species and Non- static species Species in the beginning, i.e. before Lamarckism, were thought to be unchangeable so called static but after Lamarckism the species have been considered to be non- static or dynamic.

3.

Monotypic species and Polytypic species Monotypic species are those which contain only one subspecies while polytypic species contain many subspecies.

4.

Allochronic and Synchronic species Allochronic species belong to different time period where as the Synchronic species belong to same time period.

5

Allopatric and Sympatric species Allopatric species occur in different geographical areas while Sympatric species occur in the same geographical area. Sibling species or cryptic species – Two different species which are morphologically identical or indistinguishable but are reproductively isolated, e.g. Drosophila pseudobscura and D. persimilis.

(c) Taxonomy and Systematics (d) Phenetics and Cladistics (e) Natural and artificial system of classification. (f) Chemotaxonomy and Biochemical taxonomy

14

BIOLOGY

IMPORTANT TERMS 

Nomenclature – It is the process of giving scientific names (not vernacular or local names) to the organisms.



Classification – It is the process of grouping animals and plants ito convenient categories on the basis of certain observable traits.



Identification – It is determination of correct position of an organism in the classification.



Taxonomy – It is the study of the process of classification.



Systematics – This includes the identification, nomenclature and classification of organisms based on various parameters.



New-Systematics – This covers systematic studies considering evolutionary relationship including other branches like Molecular biology, Cytology, Genetics and Biochemistry also etc.

History of Classification Hippocrates - (460-377 BC)  He classified animals into various groups like insects, fishes and birds etc. Aristotle (384-322 BC) – 

Wrote Historia animalium



Father of zoology / biology

He classified animals on the basis of red blood, into Anaima and Enaima. Anaima included animals without red blood. Enaima, with red blood, was further divided into ovipara and vivipara. Theophrastus (370-285 BC) – a Greek naturalist, and pupil of Aristotle 



Father of botany.

He classified plants into Trees, Shrubs, Under- Shrubs and Herbs, and also described around 500 plants in his book Historia plantarum. John Ray (1686) – a British botanist 



He described 1800 plant and animal species in Historia Generalis Plantarum.

 He also Introduced the terms Species, Genus and Family Carrolus Linnaeus - a Swedish naturalist 

Father of taxonomy



He coined the terms ‘Class’ and ‘Systematics’ (Term Taxonomy was given by A. P. De Condolle)



He published Systema Naturae, Genera Plantarum and Species Plantarum (1753). In S Species Plantarum he classified 4000 species of plants on the basis of sexual characters ((Artificial system of classification)



He proposed Linnaean Hierarchy with 5- taxa, i.e. Class, Order, Genus, Species and Varieties.



Linnean’s principles of Binomial Nomenclature were given in Philosophia Botanica (1751) and finally in Species Plantarum (1753) for plants, and in 10th edition of Systema Naturae (1758), for animals. The Law of Priority for nomenclature is, therefore, applicable from year 1753 for plants, and from year 1758 for animals.

Rules of Nomenclature 1.

2.

In bionomial nomenclature each scientific name has 2- components, i. Generic name (Genus), ii. Specific name/ epithet (Species) The generic name begins with capital letter, whereas the specific name, with small letter.

THE LIVING WORLD & TAXONOMY 3.

15

Both the generic and specific names, are separately underlined (if hand written), or given in italic (if printed) to indicate their Latin origin. e.g., Amoeba proteus, Panthera tigris, Homo sapiens and Pavo cristatus

4.

The first (generic) name is usually a noun, whereas the second (species) is an adjective.

5.

The scientific name of the organism is generally followed by the name (full or abbreviated) of the person/ author, who first described the species. e.g., Homo sapiens Linnaeus 1758 However, if the species, after its first publication is transferred to any other genus, or the generic name is changed, the first author’s name is given in parenthesis (brackets); e.g., Panthera leo (Linnaeus). Mr. Linnaeus assigned the species, leo, in the genus Felis. If the specific name is given in the honour of a person, then this name ends in ‘i’, if the person is male, or, in ‘ae’, if the person honoured is female. e.g., Lumbricus friendi (after Mr. R H Friend) Tautonym - It is a binomial name in which the names of genus and species are the same. e.g. Gorilla gorilla Trinomial nomenclature - It includes Genus, Species and Subspecies, and is applicable to animals only. The botanists do not recognize subspecies level.

Turrill – 

He introduced the terms α – taxonomy and β – taxonomy for Classical systematics and New systematics respectively.

Lamarck and Treviranus – 

Introduced term ‘Biology’

Cuvier –

Check Point



Father of modern Palaeontology

1. Answer the followings:



He also introduced the term ‘Phylum’

(a) What

Ernst Haeckel (1868) – 

He suggested two new kingdoms, Monera and Protista

Julian Huxley – 

Introduced the term ‘New- Systematics’

Ernst Mayr (1940) – 

He proposed Biological concept of species, on the basis of interbreeding.

Copeland (1956) – 

Suggested 4 - kingdoms - classification, i.e. Monera, Protista, Animalia and Plantae

Whittaker (1969) – 

Introduced 5- kingdom classification, i.e. Monera, Protista, Animalia, Plantae and Fungi.

Carl Woese et al.– 

They created 3-monophyletic Domains, above kingdom level, i.e. Archaea, Bacteria and Eukarya,



Introduced 6- kingdom classification on the basis of ‘sequence of Ribosomal RNAgenes’.



D. Archaea included kingdom Archaebacteria, D. Bacteria included kingdom Bacteria and D. Eukarya included 4 – kingdoms, ie. Protista, Animalia, Plantae and Fungi.

is

the

basic

unit

of

classification? (b) Who coined the term Phylum? (c) Who

introduced

classification.

Can

5-kingdom you

name

5-kingdoms? (d) Name the taxon above kingdom level. (e) Who wrote Historia Plantarum? (f) Who is father of Taxonomy? (g) For which organisms the Biological concept of species cannot be applied. (h) What is holotype?

16

BIOLOGY

Basic categories of Taxonomic hierarchy There are 7- basic categories of hierarchy1.

Kingdom

2.

Phylum (in animals)/ Division (in plants)

3.

Class

4.

Order

5.

Family

6.

Genus

7.

Species

However, there are other subcategories also, like subphylum, subclass, suborder, subfamily and subspecies. The category (taxon) ‘Cohort’ is used by palaentologists between class and order. Similarily, ‘Tribe’ has recently been introduced between subfamily and genus Please Remember that i.

two generic names in any kingdom cannot be the same

ii. all organisms, either in plant or animal-kingdom, have the Species as the lowest category. The term ‘Taxon’ is used to refer to any rank or level or category of the classification. Hence, the Dogs, Carnivora, Mammals and Animals are all taxa at different levels of hierarchy. Kingdom

Phylum or Division

Class

Order

Family

Genus

Species

The term ‘taxon’ for animals was given by Adolf Meyer (1926). Species - It is the lowest category in basic taxonomic hierarchy and has the maximum common characterstics with other species under the same genus. In genus Panthera, there are several species, like, tigris, pardus and leo etc. Genus - The genus is an aggregate or a group of closely related species. The generic names of Panthera, Felis, Homo and Canis are common. The taxon Genus has more common characterstics with other genera than the higher ranks. Family - It is the group of closely related genera, and has less common characterstics than species or genus rank. The cats and dogs belong to Felidae and Canidae families respectively. (The suffix used for family, subfamily and tribe in animals are -idae, -inae and -ini respectively.) Order - It is a higher taxon and is the assemblage of families having similar characterstics. However, the common characterstics will be fewer than at family or genus level. In mammals the common order are Primates (monkey, gorilla and human), Carnivora, Rodentia and Cetacea (whale and dolphin) Class - It is a group of related orders. The lizards, birds and cattle belong to class Reptilia, Aves and Mammalia respectively. Phylum - The classes with similar features are grouped into Phylum in animals and Division in plants. The phylum share very few common characterstics with other phyla. The common characterstics of phylum Chordata are- Dorsal tubular nervous system, Notochord and the Pharyngeal gill slits at some stage of life cycle. Other phyla are Annelida, Arthropoda and Mollusca etc. Kingdom - The phyla are grouped into still broader categories, called kingdom. You are familiar with animal kingdom and plant kingdom. Thus in above taxonomic hierarchy as we move from lower to higher (species to kingdom) rank, the number of common characterstics go on decreasing. Lower the taxon more are the common characterstics, and higher the taxon the fewer are the common features. Taxonomic categories of common animals-

THE LIVING WORLD & TAXONOMY Common Biological Name Phylum Class Order Family Genus Name Human Chordata Mammalia Primates Hominidae Homo Homo sapiens Dog Chordata Mammalia Carnivora Canidae Canis Canis familiaris Frog Chordata Amphibia Anura Ranidae Rana Rana tigrina House fly Musca domestica Arthropoda Insecta Diptera Muscidae Musca

Concept of species 1.

2.

Typological species concept•

It is simpler and widely accepted concept.

•

All individuals of a species match the ‘type specimen’ very closely.

•

The ‘type specimen’ used for the nomenclature in this system is called Holotype. The other type of specimen can be Paratype, Isotype and Lectotype etc. The Isotype is the copy of the Holotype. The Paratype is the one which is cited with the original description but is neither Holotype nor Isotype. The Lectotype is the specimen from original material, in the absence of Holotype.

Biological species concept•

It is based on interbreeding of the members.

•

It is not applicable to fossils or asexually reproducing organisms, as they cannot interbreed

Types of Classification – 1.

Artificial system of Classification - All taxonomists, from Aristotle to Linnaeus, classified organisms on the basis of external observable (morphological) characters like floral structure ( Number of stamens), root modification, leaf venation etc. In this system no weightage was given to natural and Phylogenetic relationship. Such system is based on one or a few superficial similarities. This is an arbitrary system of classification. Linnaeus also used such system of classification. This system may also be based upon habit and habitats of the organisms.

2.

Natural System of Classification - It uses more number of characters and is based upon natural affinities using homology and comparative study. Bentham - Hooker used this system of classification for angiosperms.

3.

Numerical Taxonomy ( Phenetics ) or Quantitative taxonomy - This system uses numerical methods for evaluating the similarities and differences between the species. This uses maximum number of characters, without giving extra emphasis on anyone. Sophisticated calculating machines and computers are used for statistical analysis,. This system gives equal importance and weightage to all the characters used for taxonomy. As this system was first attempted by Adanson (1763), the numerical taxonomy is also known as Adansonian system (The Phenetics is considered to be a better classification as it uses a huge number of comparative features).

4

Phylogenetic Classification (Cladistics) - This system of classification is based upon evolutionary relationship and uses morphological characters, origin and evolution of the different organisms. The ‘Family tree’ in this system is called Cladogram. This system has led to the emergence of new systematics and bio-systematics. Phylogenetic system of classification was proposed by Hutchinson.

17

18

BIOLOGY Adolf Engler and K. Prantl, both German Botanists, published ‘Phylogenetic system of classification’ in plants and considered monocots to be the more primitive than the dicot angiosperms. They published twenty volumes of classification (from algae to angiosperm) in Die Natuerlichen Phlanzenfamilien. 5

Karyotaxonomy - This system of classification uses information like chromosome number, structure of chromosomes, size and shape of chromosomes and the behaviour of chromosomes during meiosis.

6

Chemotaxonomy - This system is based on chemical products, particularly secondary metabolites. Various families of plants have been identified on the basis of raphides (Crystals of calcium oxalates)

7.

Experimental taxonomy - Here the relationship is determined on the basis of genetics, breeding experiments and the effect of captivity.

8.

Bio-chemical taxonomy - It is based on the bio-chemistry of various chemicals like hormones, pheromones etc.

The Population systematics and Biosystematics are the new branches of classification. The Biosystematics is the classification of organisms based on evolutionary history and phylogeny considering various parameters in totality, from all the fields of biology. Codes of nomenclature – 1.

International code of Botanical nomenclature (ICBN)

2.

International code of Zoological nomenclature (ICZN)

3.

International code of Bacteriological nomenclature

4.

International code of viral nomenclature (not based on binomial nomenclature)

5.

International code of nomenclature for cultivated plants

The international code of Zoological nomenclature was adopted in 1964 and was published in two languages, i.e. English and French.

TAXONOMIC AIDS The taxonomic studies of animals, plants and microorganisms help is knowing our bio-resources and their diversity. The biologists have established certain procedures and techniques to store and preserve the information as well as the specimens. The following are the important taxonomic aids 1.

Herbarium

2.

Botanical gardens

3.

Zoological parks

4.

Biological Museums

5.

Keys

6.

Manuals

7.

Flora

8.

Monograph

9.

Periodicals and catalogues

1.

Herbarium – It is the store house of dead, dried, pressed and preserved plant specimens on paper sheets, called herbarium sheets. The sheets, along with description of plant specimen, are arranged according to standard system of classification, and are stored for future use. All sheets carry labels having information about date and place of collection, English, local and botanical names, family and collector’s name etc. The herbarium sheets can be used as a quick reference for taxonomic studies.

2.

Botanical gardens - These gardens have a collection of living plants for identification and taxonomic studies. Each plant is labeled indicating its botanical or scientific name and its family. The famous Indian botanical gardens are - Indian Botanical garden, Howrah; National Botanical Research Institute, Lucknow, The world famous botanical garden is at Kew, England.

THE LIVING WORLD & TAXONOMY 3.

4.

5.

19

Zoological parks (Zoos) - In such places the wild animals are kept in protected environment under human care. As far as possible, these animals are provided the conditions similar to their natural environment. Zoos help us to learn about the food habits and behaviour of the animals in captivity. Biological Museums - These have the collection of preserved animals and plants specimens for study and reference. Biological museums are generally set up in educational institutes, i.e. School and colleges. The specimens may be preserved dry or in preservative solution in jars or containers. The insects are preserved in insect boxes after collecting, killing and pinning. The larger animals, like mammals and birds are stuffed and are chemically treated for long term preservation. Museums also have collection of animal skeletons. Keys - The key is a device or scheme used for identification of animals and plants. The keys are generally analytic in nature. Separate taxonomic keys are required for separate taxa. Such keys are of 2- types (a) Indented key or Yoked key,

Check Point 1. Fill in the blanks: (a) In Bracketed key ................ pair/s of contrasting characters are used. (b) ................ on Pheretima posthuma was written by Dr. K. N. Behl. (c) Indented key is also known as ................ . (d) In place of phylum, ................ is used, in plants. (e) The taxon ................ is used in Trinomial and not binomial, system of classification. (f) The world famous botanical garden is at ................ .

(b) Bracketed key

(g) In animals the suffix used for family

(a) Indented key – It provides sequence of choices between two or more characters. The user has to make the correct choice of statement or character for identification (b) Bracketed key - It has one pair of contrasting statements for identification. Each statement in the key is called a lead.The numbers given on the right hand side indicate the next choice of paired contrasting statements. Example –

{ { (2)(2) Flies Each set with Does not fly 1-pair of Contrasting characters present { (3)(3) Limbs Limbs absent Present { (4)(4) Gills Gills absent (1) Pinna present (1) Pinna Absent

-

-

-

go to (2) go to (3)

-

-

-

Bat Cat/Dog

-

-

-

Frog Go to (4)

-

-

-

Fish Snake

6.

Manuals – These taxonomic aids contain information for the identification of names of species found in an area, They also provide information about keys, description of family, genus and species.

7.

Flora - It contains actual account of the habitat and distribution of plants of a given area, i.e., an index to the plant species found in a particular area.

8.

Monograph (Memoir) –They are taxonomic aids that give comprehensive information on one family or genus at a given time

9.

Periodicals and Catalogues– They provide information about new additions, and update the records. The catalogues are also the means for recording information for taxonomy.

is ................ . (h) The ................ is the taxon between family and class. (i)

The international code of zoological nomenclature was published in two languages, i.e. ................ .

(j)

The term ‘taxon’ for animals was given by ................ .

20

BIOLOGY

EXERCISE - 1 | NCERT BASED QUESTIONS 1.

The growth and reproduction are mutually exclusive events

9.

in (1) Plants only (2) Animals only (3) Higher animals and plants 2.

(4) Phylum

11.

The following taxonomist is called the ‘Darwin of 20th

(1) Metabolism

(2) Homeostasis

century’.

(3) Irritability

(4) Catabolism

(1) Julian Huxley

(2) Carolus Linnaeus

(3) Whittaker

(4) Ernst Mayr

Mark the correct statement 12.

The Indian Botanical garden is located in

(3) The growth in living organisms is from inside

(1) Howrah

(2) Lucknow

(4) All of these

(3) Mumbai

(4) Mysore

Which of the followings miltiply by the process of

13.

Following taxonomic aid provides information for the identification of names of species found in an area

(1) Planaria

(2) Filamentous algae

(3) Fungi

(4) All of these

Which of the following is the defining feature of all the

14.

(1) Monograph

(2) Manual

(3) Memoir

(4) Periodical

The family ‘Felidae’ includes

(1) Growth

(2) Metabolism

(1) Cats

(2) Tigers

(3) Reproduction

(4) Self consciousness

(3) Lions

(4) All of these

The number of common characteristics are the maximum in following taxon (1) Class

(2) Order

(3) Family

(4) Phylum

15.

The term ‘Taxon’ is used for (1) The ranks of species and genus (2) The ranks up to phylum

Given below is the botanical name of mango. Mark the

(3) The species epithet only

option in which the name is correctly written

(4) Any rank of taxonomic hierarchy

(1) Magnifera Indica (2) Mangifera indica

16.

(3) Mangifera Indica (4) Mangifera indica 8.

The ‘Birds’ taxonomically represent (3) Class

living organisms?

7.

(4) Australia

The sum total of chemical reactions occurring in our body

fragmentation?

6.

(3) Berlin

(2) Order

(2) Plants grow only up to a certain age

5.

(2) Lucknow

(1) Family

(1) Only living organisms grow

4.

(1) England

(4) Lower organisms is called

3.

10.

The famous botanical garden ‘Kew’ is located in

Identify the correct sequence of taxonomic categories (1) Species-order-kingdom-phylum (2) Species-family -genus-class

17.

The assemblage of families with common features, is called (1) Class

(2) Phylum

(3) Genus

(4) Order

The binomial nomenclature was given by

(3) Genus-species -order -phylum

(1) Lamarck

(2) Ernst Mayr

(4) Species -genus-order-phylum

(3) Carolus Linnaeus (4) Cuvier

THE LIVING WORLD & TAXONOMY

21

EXERCISE - 2 | Window to Competitive Exams

7.

8.

tp

ht

12.

s:

//n

11.

ee tm

ed i

10.

om

.c

ot

18.

19.

20.

ca

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The branch of biology dealing with the process how to improve the human race by selective breeding is: [AFMC ’97; AIIMS ’97] (1) euthenics (2) obstetrics (3) euphenics (4) eugenics The branch which is associated with diagnosis, prevention and cure of mental disorders is: [AIIMS ’97] (1) neurology (2) psychiatry (3) psychology (4) neuropsychiatry A pregnant woman who has done amniocentesis test finds an extra Barr body in her embryo. The syndrome which is likely to be associated with the embryo is: [AIIMS ’97] (1) Down syndrome (2) Patau syndrome (3) Edward syndrome (4) Klinefelter syndrome Study of antibodies alongwith antigens is [JIPMER’92; AFMC’97] (1) Serology (2) Haematology (3) Anthology (4) Cytology Foetal sex can be determined by examining cells from the amniotic fluid by looking for: [CBSE ’97] (1) Autosomes (2) Chiasma (3) Kinetochore (4) Barr bodies and sex chromosomes Certain discoveries which are made by chance, are called (1) Authenticated discovery [Punjab’97] (2) Etiology (3) Serendipity (4) Teleology The correct sequence of taxonomic categories is [BHU ‘89; CBSE ‘92; Haryana ‘94; Punjab ‘97] (1) Class-phylum-tribe-order-family-genus-species (2) Phylum-order-class-tribe-family-genus-species (3) Division-class-order-family-tribe-genus-species (4) Division-class-family-tribe-order-genus-species System of classification used by Linnaeus was [CBSE ‘89; MP ‘97] (1) Natural system (2) Artificial system (3) Phylogenetic system (4) Asexual system Study of interaction of antigens and antibodies in the blood is: [JIPMER ’93, ’98] (1) serology (2) haematology (3) angiology (4) cryobiology The book ‘Systema Naturae’ deals with [MP ‘98] (1) Ecosystem (2) Solar system (3) Natural selection (4) Classification of animals The characteristic which define a family are more general than those which define a [JIPMER ‘98] (1) Genus (2) Class (3) Phylum (4) Cohort

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em

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The term ‘biology’ was introduced by : [MP ’95] (1) Aristotle (2) Darwin (3) Lamarck and Treviranus (4) Linnaeus Study of rudimentary organs is: [BCECE ’95] (1) etiology (2) dysteleology (3) chirology (4) dermatology Cultivation of fishes, oysters, shrimps and crabs come under [CBSE ’92, Haryana ’95] (1) sericulture (2) aquaculture (3) silviculture (4) pisciculture Germplasm preservation at ultra-low temperatures around –196°C is called as: [AMU ’95] (1) cryopreservation (2) ultrapreservation (3) chemical preservation (4) physical preservation In which of them, induced breeding is effective? (1) Sericulture (2) Apiculture [MP ’95] (3) Lac culture (4) Pisciculture Natural system of classification is based on [CPMT ‘95] (1) Morphology (2) Evolutionary trend (3) Anatomy (4) All above Which of the classification is considered as a modern phylogenetic system? [BHU ‘96] (1) Linnaeus (2) Bentham and Hooker (3) Hutchinson (4) Engler and Prantl ‘Taxon’ is the unit of [CBSE ‘96] (1) a group of species (2) a group of genera (3) a group of orders (4) a group of taxonomy Branch of Zoology dealing with the study of behaviour of animals is: [RPMT ’96] (1) ethology (2) ecology (3) sociology (4) anthropology Double helical model of DNA molecule was proposed by: [EAMCET ’96] (1) Watson and Crick (2) Knoll and Ruska (3) Beadle and Tatum (4) Feulgen and Rossenbeck Binomial system of nomenclature for plants is effective from [JIPMER ‘97] (1) 1771 (2) 1758 (3) 1753 (4) 1736 Two similar holotypes are called [BHU ‘97] (1) Isotypes (2) Neotypes (3) Syntypes (4) Mesotypes

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BIOLOGY The particular purpose of classification of living organisms is to [CBSE ‘99] (1) name the living organisms (2) explain the origin of living organisms (3) trace the evolution of living organisms (4) Facilitate identification of unknown organisms Who developed the ‘key’ for identification of animals? [MP ‘99] (1) John Ray (2) Goethe (3) Theophrastus (4) George Cuvier The technique by which “Dolly” the sheep obtained is termed as: [CBSE ’99] (1) cloning by gene transfer (2) cloning by nuclear transfer (3) cloning without the help of gametes (4) cloning by tissue culture of somatic cells What is the name of the book written by Aristotle? (1) Histoire Naturella [Punjab ’99] (2) Systema Naturae (3) Historia Animalia (4) Philosophie Zoologique The study of development of an organism from the egg to the adult stage is known as: [MP ’99] (1) embryology (2) evolution (3) cell theory (4) genetics One of the sciences for which training in biology is essential, namely the science of treating diseases with drugs or curative substances, is called: [AMU ’99] (1) Medicine (2) Pharmacy (3) Pest control (4) Physiotherapy Study of form and structure of organisms is:[DPMT ’99] (1) ecology (2) taxonomy (3) anatomy (4) morphology Karyotaxonomy is a modern branch of classification which is based on: [Punjab ’99] (1) organic evolution (2) number of nuclei (3) number of chromosomes (4) trinomial nomenclature Which of the following species is restricted to a given area? [CPMT ‘99] (1) Sibling species (2) Sympatric species (3) Endemic species (4) Allopatric species The basis of karyotaxonomy is [MP ‘99] (1) Number of nucleoli (2) Sedimentation rate of ribosomes (3) Chromosome banding (4) Chromosome number One of the following book was written by Aristotle (1) Historia animalium [MP ‘99] (2) Historia plantarum (3) Systema naturae (4) Pflenzen familien die naturalichen A system of classification in which a large number of traits are considered is [CBSE ‘99] (1) Artificial system (2) Natural system (3) Synthetic system (4) Polyogenetic system

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The study of ageing is known as [Punjab 2000] (1) Polynology (2) Gerontology (3) Genetics (4) Spermology Binomial nomenclature consists of [CET Chd 2000] (1) One Latin and one vernacular name (2) One scientific name and one Latin name (3) One generic and one specific name (4) One scientific name and one vernacular name Amniocentesis is the withdrawal of amniotic fluid during: [MP 2000] (1) gestation (2) lactation (3) menopause (4) menstruation Amniocentesis detects: [CBSE ’97; Punjab 2000] (1) deformity in brain (2) hereditary diseases (3) deformity in heart (4) all of these The phylogenetic system refers to grouping [Punjab 2000] (1) According to floral similarities (2) Of plants in order of their increasing complexities (3) According to evolutionary trends (4) According to all morphological characters. The study of trends in human population growth and the prediction of future development is known as: [Kerala 2000] (1) Sociology (2) Geography (3) Demography (4) Anthropology Choose the correct pair : [RPMT ’96; CPMT ’2000; JK 2000] (1) Sericulture – fish (2) Silviculture – silkworm (3) Apiculture – honeybee (4) Pisciculture – forestry The cell nucleus was discovered by: [CPMT ’96;Punjab 2000; Kerala 2000] (1) Robert Brown (2) Schleiden (3) Robert Hooke (4) Schleiden The first cloned animal of the world is [CBSE 2000] (1) Molly-Sheep (2) Polly-sheep (3) Dolly-sheep (4) Molly-buffalo Evolutionary history of a group of organisms is called : [Haryana 2000] (1) ontogeny (2) taxonomy (3) phylogeny (4) systematics Binomial nomenclature was introduced by : [CBSE ’90, ’94; BHU ’91; VVMC ’01] (1) Linnaeus (2) Darwin (3) Aristotle (4) de Candolle Phylogenetic evidence cannot be given by: [VVMC ’01] (1) embryology (2) physiology (3) morphology (4) biogeography Who appears to have first used the term ‘ecology’ in 1886? [BHU ’01] (1) F. Clement (2) E. Haeckel (3) E.J. Kormondy (4) I.G.S. Hilaire

THE LIVING WORLD & TAXONOMY 49.

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Branch of biology dealing with mechanism of heredity is: [MP ’98; AFMC ’01] (1) genetics (2) cytology (3) eugenics (4) euthenics The study of action of drug is known as: [MP ’01] (1) pysiology (2) pharmacology (3) pharmacognosy (4) pharmaceutical chemistry If a botanist has to nomenclate a similar species, he will use [JIPMER ‘01] (1) Isotype (2) Neotype (3) Neotype (4) Mesotype Which of the following name is correctly written? (1) Ficus Bengalensis [MAHE ‘01] (2) apis Indica (3) Trypanosoma gambiense (4) Pheretima posthuma Kingdom Monera comprises: [AMU ‘01] (1) all eukaryotes (2) all prokaryotes (3) both eukaryotes and prokaryotes (4) none of these Inbreeding is possible between two members of a/an [MAHE ‘01] (1) Order (2) Genus (3) Species (4) Family What is true for archaebacteria? [CBSE ‘01] (1) All halophytes (2) All fossils (3) All photosynthetic (4) Oldest living beings The taxonomic status of an organism can be changed by changing [AFMC ‘02] (1) anatomy (2) physiology (3) morphology (4) genetic make up Species is [AFMC ‘02] (1) population of one type (2) a group of interbreading populations (3) a group of individuals inhabiting a geographical area (4) population of individuals having same genotypes and phenotypes The smallest unit of classification is [IPU ‘02] (1) Species (2) Subspecies (3) Variety (4) Genus Who was the first to describe that species is the unit of classification? [BVP ‘02] (1) John Ray (2) Huxley (3) Linnaeus (4) Candolle True species are [CBSE ‘02] (1) Interbreeding (2) Sharing the same niche (3) Feeding on the same food (4) Reproductively isolated Molecular biology is the study of [CET’02] (1) Structure, function and reproduction of cell (2) Physio-chemical studies of biomolecules (3) Studying tissues under microscope (4) Metabolic activity of life.

23 62. 63.

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Ichthyology is the study of [CMC’02] (1) Snakes (2) Lizards (3) Birds (4) None above While solving a problem a scientific method is employed. Which of the following is incorrect? [CET’02] (1) The observations are made directly or indirectly (2) A possible hypothesis is formulated to explain the phenomenon (3) Hypothesis is subjected to experiment (4) No control is kept with an experiment. Limnobiology is study of [Vellore’02] (1) Marine life (2) Fresh water ponds and lakes (3) Snails and slugs (4) Forest development Pick up the correct match [Haryana’02] Column I (Fathers) Column II (Branches) I. Aristotle A. Eugenics II. Galton B. Green Revolution III. Gregor Mendel C. Zoology IV. Borlaug D. Genetics (1) I-A, II-B, III-C, IV-D (2) II-A, IV-B, I-C, III-D (3) III-A, I-B, II-C, IV-D (4) IV-A, III-B, II-C, I-D The term ‘mutation’ was coined by [Haryana’02] (1) Bateson (2) Morgan (3) De Vries (4) Mendel One of the following is a correct sequence [Punjab 2000; IPU’02] (1) Observation, hypothesis, experiment, theory (2) Observation, hypothesis, theory, experiment (3) Theory, hypothesis, observation, experiment (4) Experiment, hypothesis, theory & observation Study of ants is: [JIPMER ’02] (1) myology (2) mycology (3) malacology (4) myrmecology Which of the following subdivisions deals with fossils? [Orissa ’90, ’95; CET ’90, ’94; CBSE ’91, JK ’02] (1) Ecology (2) Ornithology (3) Ethology (4) Palaeontology The branch of biology which deals with the study of identification, nomenclature and classification of organisms is [Kerala’02] (1) Exobilogy (2) Ecology (3) Taxonomy (4) Toxicology Inland fisheries is: [St. Johns ’02] (1) fishing inside water (2) fishing in island (3) fish in culture pond (4) fishing in freshwater Synecology refers to the ecological study of: [CPMT ’95; JIPMER ’02] (1) plants (2) animals (3) community (4) microbes

24 73.

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BIOLOGY The branch of biology which deals with the study of identification, nomenclature and classification of organisms is: [CPMT ’91; Kerala ’02] (1) ecology (2) taxonomy (3) exobiology (4) toxicology The first mammal clone “Dolly” was created by: [Kerala ’02] (1) Ian Wilmut (2) T.H. Morgan (3) Robert Briggs (4) Thomas King C. Linnaeus is famous for [IPU ‘02] (1) Coining the term ‘systematics’ (2) Introducing binomial nomenclature (3) Giving nature system of classification (4) All of these Taxon includes [Punjab ‘02] (1) Genus and species (2) Kingdom and division (3) All ranks of hierarchy (4) None above In taxonomy, ‘class’ comes in between (1) Kingdom and phylum [CET Chd ‘02] (2) Phylum and order (3) Order and family (4) Family and genus Basic unit of taxonomy is [DPMT ‘97; Kerala ‘02] (1) Genus (2) Species (3) Family (4) Order Sequence of which of the following is used to determine the phylogeny? [CBSE ‘02] (1) DNA (2) t-RNA (3) r-RNA (4) m-RNA The replacement of two kingdom grouping by five kingdom classification was proposed in the year [AMU ‘01; Kerala ‘03] (1) 1859 (2) 1969 (3) 1862 (4) 1919 Karyotaxonomy is a branch of [Jharkhand ‘03] (1) cytotaxonomy (2) artificial taxonomy (3) numerical taxonomy (4) phylogenetic taxonomy The theory of spontaneous generation of abiogenesis was disproved by : [HP ’03] (1) A.I. Oparin (2) Sidney Fox (3) A.R. Wallace (4) Louis Pasteur Who introduced the term ‘cell’ ? [BV Pune’03] (1) Leeuwenhoek (2) Robert Hooke (3) J. Schleiden (4) Schwann The science of engineering and technology which is applied to life sciences is [AFMC’03] (1) Biotechnology (2) Biological science (3) Genetic engineering (4) Pathology Who is the father of biology ? [CET’03] (1) Hippocrates (2) Theophrastus (3) Aristotle (4) Darwin

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Non poisonous leeches were used for preventing the clotting of blood in the post operative cases during 600BC by [Kerala’03] (1) Atreya (2) Charaka (3) Agnivesa (4) Susruta Aquaculture does not include: [BHU ’03] (1) Pisces (2) Prawns (3) Silkworm (4) Shell fishery Choose the correct arrangement [MHCET ‘03] (1) cohort → class → family → genus (2) class → cohort → family → genus (3) series → cohort → family → genus (4) order (cohort) → series → species → family In taxonomy ‘series’ is a group of [MHCET ‘03] (1) species (2) classes (3) closely related families (4) closely related superorders ‘Genetic species concept’ was given by [BVP ‘03] (1) Lotsy (2) Lamarck (3) Linnaeus (4) Ernst Mayr The branch of biology dealing with structure, function and reproduction of cell is [JK’05] (1) cytology (2) anatomy (3) histology (4) cell biology The term protoplasm for the cell contents was coined by [JK’05] (1) Von Mohl (2) J. E. Purkinje (3) J. S. Huxley & Hertwig (4) M. Schultza Genes were first artificially synthesised by [JK’05] (1) Khorana (2) Watson (3) Galton (4) Mendel The cell as a basic unit of structure of living things was discovered by [JK’05] (1) Aristotle (2) Robert Hooke (3) Schleiden and Schwann (4) Gregore Mendel Select the false statement [Kerala’05] (1) Pasteur prepared vaccine against anthrax (2) Susruta Samhita describes the classification of plants and animals (3) Pasteur provided experimental evidence in support of the theory of spontaneous generation (4) Dhanwanthiri is regarded as the father of ancient Indian medicine. Molecular biology is concerned with the study of [KCET’05] (1) structure and functions of polymers of life (2) all aspects of micro organisms (3) the process by which molecules of chemical substances organized into primitive form of life (4) the chemistry of living organisms

THE LIVING WORLD & TAXONOMY 97.

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Entomology is concerned with the study of [KCET’05] (1) formation and properties of soil (2) agricultural practices (3) various aspects of human life (4) various aspects of insects Which one of the following is correctly matched? [Kerala’05] (1) Frederick Griffith - discovered the phenomenon of transformation (2) Linus Pauling - isolated DNA for the first time (3) Francis Crick - proposed one gene one polypeptide hypothesis (4) Jacob and Monod - proposed the wobble hypothesis Green revolution was given by [BCECE’05] (1) Darwin (2) Wallace (3) Norman Borlaug (4) R. Mishra Match the list-I with list-II and find out the correct answer from the code given below: [Manipur’05] List-I List II (a) Rosalind Franklin 1. Mutation (b) Hugo de Vries 2. Chromosome (c) W. Waldeyer 3. Ribose sugar (d) Levin 4. DNA (1) (a) : 1, (b) : 2, (c) : 4, (d) : 3 (2) (a) : 4, (b) : 1, (c) : 3, (d) : 2 (3) (a) : 4, (b) : 1, (c) : 2, (d) : 3 (4) (a) : 3, (b) : 2, (c) : 1, (d) : 4 Father of green revolution in India is [MAHE’05] (1) M. S. Swaminathan (2) N. Borlaug (3) Mishra (4) P. Maheswari Match the following : [EAMCET’05] List I List II A. Milstein 1. Interferon B. Erythropoietin 2. r-DNA C. Fusogen 3. Hybridoma D. Lindermann 4. Poly Ethylene Glycol (1) A-3, B-2, C-4, D-1 (2) A-2, B-3, C-4, D-1 (3) A-3, B-2, C-1, D-4 (4) A-2, B-3, C-4, D-1 Study the following Lists : [EAMCET’05] List I List II A. Hatch and Slack I. Electron microscope B. Theophrastus II. Citric acid cycle C. Knoll and Ruska III. Micrographia D. Robert Hooke IV. C4 pathway V. Historia plantarum The correct match is (1) A-IV; B-V; C-I; D-III (2) A-IV; B-V; C-I; D-II (3) A-II; B-IV; C-V; D-III (4) A-II; B-III; C-IV; D-I Binomial nomenclature means writing the name of a plant into two names. These two names refer to [Manipur ‘05] (1) class and order (2) family and genus (3) genus and species (4) order and genus

25 105. Two species which are morphologically almost identical but they do not interbreed. Such species are called (1) evolutionary species [Kerala ‘05] (2) sibling species (3) polytipic species (4) sympatric species 106. Reproduction can occur within members of a [AMU ‘05] (1) species (2) genus (3) order (4) family 107. Father of taxonomy is [AMU ‘05] (1) Bentham Hooker (2) Hutchinson (3) Linneaus (4) Whittaker 108. In five kingdom system of classification, how many kingdoms contain eukaryotes? [Orissa ‘05] (1) four kingdoms (2) one kingdom (3) two kingdoms (4) three kingdoms 109. Englar and Prantle published a phylogenetic system in the monograph [Kerala ‘05] (1) Die Naturlichen Pflanzen Familien (2) Historia plantarum (3) Species plantarum (4) Genera plantarum 110. Classification based on chromosome number is called [BCECE ‘05] (1) numerotaxonomy (2) cytotaxonomy (3) chemotaxonomy (4) none of these 111. Binomial nomenclature was first mentioned in the book [Orissa ‘05] (1) Systema naturae (2) Historia animalium (3) Historia plantarum (4) Philosophia Botanica 112. Modern system of classification classified the organisms in .............. kingdom. [Haryana ‘05] (1) one (2) two (3) four (4) five 113. Binomial nomenclature was given by [BHU ‘05, ‘06] (1) Lamarck (2) Linnaeus (3) Darwin (4) Tijo and Levan 114. Select the false statement [Kerala’06] (1) scientists who study and contribute to the classification of organisms are known as systematists (2) Carolus Linnaeus developed the first scientific system of naming species (3) a five kingdom arrangement of organisms was introduced by R.H. Whittaker (4) genus is a group of species which are related and have more characters in common as compared to species 115. In the classification of plants, the term cladistics refers to the [Kerala’06] (1) phylogenetic classification (2) sexual classification (3) artificial classification (4) natural classification 116. Bioinformatics is an interdisciplinary branch which is concerned with the application of [KCET06] (1) engineering techniques in biological studies (2) chemistry in understanding the biological phenomenon (3) physics in understanding various life processes (4) information science in analysing the biological data

26 117. Most widely used bioweapon is [BHU’06] (1) Bacillus (2) Pseudomonas putida (3) Bacillus anthracis (4) none of these 118. Human genome project was discovered by [AMU’06] (1) Francis Collins and Roderick (2) Watson and Crick (3) Beadle and Tatum (4) Paul Berg and Wollman 119. Match the following and choose the correct combination form the option given. [Karala’06] a. Walter Sutton 1. discovered penicillin b. Thomas Hunt 2. discovered the chromosomal basis of heredity c. James Watson 3. described the phenomena of linkage and crossing over d. Alexander 4. discovered the Fleming double helical structure of DNA (1) a–1, b–4, c–2, d–3 (2) a–2, b–3, c–1, d–4 (3) a–3, b–2, c–1, d–4 (4) a–2, b–3, c–4, d–1 120. Identify from the following, the only taxonomix category that has a real existence [KCET’06] (1) genus (2) phylum (3) species (4) kingdom 121. The term ‘New systematics’ was coined by [CBSE ‘88; AMU ‘93; AFMC ‘93; CPMT ‘06] (1) Bentham and Hooker (2) Linnaeus (3) Julian Huxley (4) De Condolle 122. The species separated by geographical barriers are termed [AFMC ‘02; Orissa ‘06] (1) sibling (2) allopatric (3) neopatric (4) sympatric 123. Phylogenetic system of classification was proposed by [AMU ‘86; CPMT ‘88; BHU ‘88, ‘91; Orissa ‘06] (1) Hutchinson (2) Bentham and Hooker (3) C. Linnaeus (4) Santapau 124. Five kingdom classification system was proposed by [HPMT’07] (1) RH Whittaker (2) Carolus Linnaeus (3) Engler & Prantl (4) Darwin 125. Two plants can be conclusively said to belong to the same species if they: [CBSE’07] (1) have same number of chromosomes (2) can reproduce freely with each other and form seeds. (3) have more than 90 per cent similar genes (4) look similar and possess identical secondary metabolites. 126. ICBN stands for: [CBSE’07] (1) Indian Code of Botanical Nomenclature (2) Indian Congress of Biological Names (3) International Code of Botanical Nomenclature (4) International Congress of Biological Names

BIOLOGY 127. Phylogenetic system of classification is based on : [CBSE’09] (1) Flora characters (2) Evolutionary relationships (3) Morphological features (4) Chemical constituent 128. Which one of the following is considered important in the development of seed habit? [CBSE PMT 2009] (1) Heterospory (2) Haplontic life cycle (3) Free -living gametophyte (4) Dependent sporophyte 129. The binomial of sunn hemp is [Kerala PMT 2009] (1) Crotolaria juncea (2) Erythrina indica (3) Glycine max (4) Arachis hypogea (5) Dalbergia sissoo 130. Which one of the taxonomic aids can give comprehensive account of complete compiled information of any one genus or family at a particular time? [Kerala PMT 2009] (1) Taxonomic key (2) Flora (3) Herbarium (4) Monograph (5) Dictionary 131. Which one of the following series includes the orders ranales, parietales and malvales? [Kerala PMT 2009] (1) Bicarpellatae (2) Thalamiflorae (3) Calyciflorea (4) Disciflorae (5) Inferae 132. Cold-blooded animals fall under the category of [DPMT’10] (1) Ectotherms (2) Psychrotherms (3) Endotherms (4) Thermophiles 133. Binomial nomenclature was given by [AFMC’10] (1) R.H. Whittaker (2) Linnaeus (3) Aristotle (4) Theophrastus 134. ‘Taxa’ differs from ‘taxon’ due to [DPMT- 2010] (1) This being a higher taxonomic category than taxon (2) This being lower taxonomic category than taxon (3) This being the plural of taxon (4) This being the singular of taxon 135. A group of related genera, with still less number of similarities as compared to the genus and species, constitutes [DPMT- 2010] (1) Order (2) Class (3) Family (4) Division 136. Classification of organisms based on evolutionary as well as genetic relationships is called [DPMT- 2010] (1) Biosystematics (2) Phenetics (3) Numerical taxonomy (4) Cladistics 137. Which of the following statements regarding universal rules of nomenclature is wrong? [Kerala PMT 2010] (1) The first word in a biological name represents the genus. (2) The first word denoting the genus starts with a capital letter. (3) Both the words in a biological name, when handwritten, are separately underlined. (4) Biological names are generally in Greek and written in italics. (5) The second component in a biological name denotes the specific epithet.

THE LIVING WORLD & TAXONOMY 138. Match the following and choose the correct combination from the options given. [Kerala PMT 2010]

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145.

(1) A – 1, B – 2, C – 4, D – 3 (2) A – 4, B – 3, C – 2, D – 1 (3) A – 2, B – 4, C – 1, D – 3 (4) A – 3, B – 4, C – 2, D – 1 (5) A – 4, B – 2, C – 3, D – 1 Taxonomic hierarchy refers to [DPMT- 2011] (1) Step-wise arrangement of all categories for classification of plants and animals (2) A group of senior taxonomists who decide the nomenclature of plants and animals (3) A list of botanists or zoologists who have worked on taxonomy of a species or group (4) Classification of a species based on fossil record Which one of the following animals is correctly matched with its particular named taxonomic category ? (1) Tiger - Tigris, the species [CBSE PMT 2011] (2) Cuttle fish - mollusca, a class (3) Humans - primata, the family (4) Housefly - Musca, an order Which one of the following aspects is an exclusive characteristic of living things ? [CBSE PMT 2011 M] (1) Isolated metabolic reactions occur in vitro (2) Increase in mass from inside only (3) Perception of events happening in the environment and their memory (4) Increase in mass by accumulation of material both on surface as well as internally. Cladistics can be best defines as [AFMC 2011] (1) the relationship between sub-species and species (2) relationship between two most forward races (3) relationship between endangered and surviving species (4) method of classification that attempt to interfere phylogenetic relationship The first organisms to appear on earth were [AFMC 2011] (1) photoautotrophs (2) chemoautotrophs (3) chemoheterotrophs (4) coacervates One of the most important functions of botanical gardens is that [AFMC 2011] (1) they provide a beautiful area for recreation (2) one can observe tropical plants there (3) they allow ex-situ conservation of germ plasm (4) they provide the natural habitat for wildlife The basic unit of classification is [JIPMER-2011] (1) species (2) genus (3) family (4) phylum

27 146. Select the incorrect statements. Kerala PMT 2011] (1) Lower the taxon, more are the characteristics that the members within the taxon share. (2) Order is the assemblage of genera which exhibit a few similar characters. (3) Cat and dog are included in the same family Felidae. (4) Binomial nomenclature was introduced by Carolus Linnaeus. (1) A, B & C (2) B, C & D (3) A & D (4) C & D (5) B & C 147. Which one of the following organisms is scientifically correctly named, correctly printed according to the International Rules of Nomenclature and correctly described? [2012M] (1) Musca domestica - The common house lizard, a reptile. (2) Plasmodium falciparum – A protozoan pathogen causing the most serious type of malaria. (3) Felis tigris - The Indian tiger, well protected in Gir forests. (4) E.coli - Full name Entamoeba coli, a commonly occurring bacterium in human intestine. 148. A group of interconnected genera is called [AFMC 2012] (1) family (2) order (3) phylum (4) class 149. Systema Naturae was written by [JIPMER-2012] (1) Linnaeus (2) Aristotle (3) Hippocrates (4) Darwin 150. Which one of the following is a taxonomical aid for identification of plants and animals based on similarities and dissimilarities? [Kerala PMT 2012] (1) Flora (2) Keys (3) Monographs (4) Catalogues (5) Manuals 151. Which one of the following organisms is scientifically correctly named, correctly printed according to the International Rules of Nomenclature and correctly described? [CBSE PMT 2012M] (1) Musca domestica - The common house lizard, a reptile. (2) Plasmodium falciparum – A protozoan pathogen causing the most serious type of malaria. (3) Felis tigris - The Indian tiger, well protected in Gir forests. (4) E.coli - Full name Entamoeba coli, a commonly occurring bacterium in human intestine. 152. Scientific name of Mango plant is Mangifera indica (Linn.) Santapau. In the above name Santapau refers to [AIIMS 2012] (1) Variety of Mango (2) A taxonomist who proposed the present nomenclature in honour of Linnaeus (3) A scientist who for the first time described Mango plant (4) A scientist who changed the name proposed by Linnaeus and proposed present name

28 153. Which one of the following is not a correct statement? [AIPMT (NEET) 2013] (1) Botanical gardens have collection of living plants for reference. (2) A museum has collection of photographs of plants and animals (3) Key is taxonomic aid for identification of specimens. (4) Herbarium houses dried, pressed and preserved plant specimens. 154. Which one of the following is not a correct statement ? [AIPMT (NEET) 2013] (1) Botanical gardens have collection of living plants for reference. (2) A museum has collection of photographs of plants and animals (3) Key is taxonomic aid for identification of specimens. (4) Herbarium houses dried, pressed and preserved plant specimens. 155. The common characteristics between tomato and potato will be maximum at the level of their [NEET Kar. 2013] (1) Genus (2) Family (3) Order (4) Division 156. Which of the following is less general in characters as compared to genus? [AIIMS 2013] (1) Species (2) Division (3) Class (4) Family 157. Assertion : Taxon and category are different things. Reason : Category shows hierarchical classification. [AIIMS 2013] (1) If both Assertion and Reason are correct and Reason is the correct explanation of Assertion. (2) If both Assertion and Reason are correct, but Reason is not the correct explanation of Assertion. (3) If Assertion is correct but Reason is incorrect. (4) If Assertion is incorrect but Reason is correct. 158. Which of the following statements regarding growth is false? [Kerala PMT 2013] (1) Increase in mass and increase in number of individuals are twin characterics of growth. (2) In plants, growth by cell division is seen only upto a certain stage. (3) Growth exhibited by non-living objects is by accumulation of material on the surface. (4) A multicellular organism grows by cell division. (5) Growth in in vitro culture of unicellular organisms can be observed by counting the number of cells.

BIOLOGY 159. Consider the following statements. [Kerala PMT 2013] (i) Genus comprises a group of related species. (ii) Taxon represents a taxonomic group of individual organisms. (iii) Family comprises a group of related genera (iv) Taxonomic category class includes related orders. Of the above statements (1) (i), (ii), and (iv) are correct (2) (ii) and (iv) are correct (3) (i), (iii) and (iv) are correct (4) (ii), (iii) and (iv) are correct (5) (i), (ii) and (iii) are correct 160. Match the following and choose the correct combination from the options given. [Kerala PMT 2013] Column I Column II (Common Name) (Taxonomic Category Family) (1) Man (1) Poaceae (2) Datura (2) Anacardiaceae (3) Mango (3) Solanaceae (4) Wheat (4) Hominidae (1) A-4, B-3, C-2, D-1 (2) A-4, B-3, C-1, D-2 (3) A-1, B-2, C-3, D-4 (4) A-1, B-3, C-2, D-4 (5) A-3, B-4, C-1, D-2 161. Which of the following taxonomic category of housefly is wrongly matched? [Kerala PMT 2013] (1) Genus Musca (2) Family Muscidae (3) Order Primata (4) Class Insecta (5) Phylum Arthropoda 162. Assertion : Taxon and category are different things. Reason : Category shows hierarchical classification. [AIIMS 2014] (1) If both Assertion and Reason are correct and Reason is the correct explanation of Assertion. (2) If both Assertion and Reason are correct, but Reason is not the correct explanation of Assertion. (3) If Assertion is correct but Reason is incorrect. (4) If Assertion is incorrect but Reason is correct. 163. The scientist widely regarded as the triple crown of Biology X is : [AMU’s 2015] (1) R.H. Whittaker (2) Carolus Linnaeus (3) Ernst Mayr (4) Zimmermann 164. “Omnis celulae e cellula” was stated by: [AMU’s 2015] (1) Schwan (2) Schleiden (3) Purkinje (4) Virchow

THE LIVING WORLD & TAXONOMY

29

EXERCISE - 3 | Test Yourself Which one of the following scientist is known as the ‘Father of Anatomy’? (1) Andreas Vesalius (2) Aristotle (3) Susruta (4) William Harvey

2.

In Louis Pasteur’s classical experiment the following set of flasks served as control (1) Swan – necked flasks (2) Straight and long necked flasks (3) Flasks having different nutrient medium (4) Flasks without broth

13.

HIV was discovered by (1) Luc Montagnier (3) Ian Willmut

Scientists have undertaken the study of exobiology because (1) Earth has become over-crowded (2) People want to live in isolation (3) The security of earth can be better managed (4) It is human nature to explore the unknown

m

ac ad e

Mark the incorrect statement in the following (1) Organisms cannot live in isolation (2) Phenomenon of accidental discoveries is known as Serendipity (3) Amniocentesis can be helpful in studying chromosomal disorders of foetus (4) Most important part of scientific experimentation is accurate observation. Mark the wrong statement in the following (1) In weaver bird (Baya) the nest is built by male (2) Big-Bang theory for the origin of universe was given by Hubble (3) Replication is the characteristic of living beings (4) Cicada insect is known for producing penetrating sound and very long embryonic period

17.

Mark the wrong statement (1) Biology is called the science of exceptions and is not governed by laws (2) Teleological explanations lack experimental verifications (3) Hypothesis and theories both are subject to change (4) None of these

al

tm

//n ee

tp s:

Serendipity means (1) Study of serpents (Snakes) (2) Scientific Study (3) Science of exceptions (4) Discovery by chance

The science dealing with the training of the handicapped persons is called (1) Physiotherapy (2) Occupational therapy (3) Biomedical engineering (4) Naturopathy

16.

ed ic

The most important component of experimentation is the (1) Material (2) Data of experiment (3) Control experiment (4) Technique used

(2) Craig C Mello (4) J. Watson

.c

15.

y.

7.

ht

The term ‘Biology’ was assigned by : (1) Miller (2) A. R. Wallace (3) Empedockle (4) None of these

ot

The science dealing with extracting of selected genes from an organism or synthesizing copies of genes and inserting them into another completely different organism is called (1) Biotechnology (2) Biomedical engineering (3) Medical transcription (4) Genetic engineering Karyology is the study of (1) Blood (2) Heart (3) Nucleus (4) Cartilage

9.

12.

14.

6.

8.

The study of animal behaviour especially in relation to ecology and physiology is called (1) Exobiology (2) Ethnology (3) Autecology (4) Ethology

sp

5.

The idea of ‘fixity of species’ was first discarded by (1) Charles Darwin (2) Aristotle (3) Lamarck (4) Walter Sutton

11.

og

4.

The following scientist has been awarded Nobel prize on his work on Ribosomes (1) Montagnier (2) V. Ramakrishnan (3) Craig C Mello (4) Stanley Cohen

Which of the following is not a myth or disbelief? (1) Snake dances on the tune of the flute of snake charmer (2) HIV can be transmitted through placenta or mother’s milk (3) One can catch malaria in marshy area due to foul air (4) Snakes suck milk from the teats of cattle

bl

3.

10.

om

1.

30 18.

19.

20.

BIOLOGY The clone of Dolly sheep was prepared by Scottish scientists in the year, between (1) 1980- 1990 (2) 1990- 2000 (3) 2000- 2010 (4) 1970- 1980 The chain of evolution, Scala Naturae, was formulated by (1) Manu (2) Charaka (3) Aristotle (4) A V Leeuwenhoek Match the name of the scientist of column I with the field

27.

28.

21.

Norman E. Borlaug I.

B.

Ian Wilmut

II.

C.

Stanley Cohen

III. Green revolution

D.

H. G. Khorana

IV. Dolly sheep

(1) AIII, BII, CIV, DI

(2) AIII, BIV, CII, DI

(3) AIV, BIII, CI, DII

(4) AII, BI, CIII, DIV

Following field is related to the production of an organism with new combinations of inherited properties

(3) Biomedical engineering

Phenetic classification is based on (1) Sexual characteristics (2) The ancestral lineage of existing organisms (3) Numerical methods for the study of observable characters in an organism (4) Dendrograms based on DNA characteristics

33.

Which statement is incorrect is relation to Linnaeus (1) He was Swedish (2) He published his first paper on sexuality of plants (3) His system of classification was based on natural system (4) He wrote famous book Systema Naturae.

34.

Artificial system of classification classifies plants on the basis of : (1) One or two characters (2) Phylogenetic trends (3) Many naturally existing characters (4) None of the above

35.

Natural classification differs from artificial classification in taking into account (1) Only one character (2) Only habitat (3) All the similarities between animals (4) All the above

36.

Polytypic species are those which (1) Do not interbreed (2) Are distributed in different geographical areas (3) Have two or more subspecies (4) Belong to different time periods

(2) Micrographia (4) Scala Naturae

24.

The term ‘Molecular biology’ was first used and defined by (1) R.W. Holley

(2) W.T. Astbury

(3) William Bateson

(4) S. Cohen

The gastritis and the peptic ulcer are the result of the infection of (1) Human papilloma virus (2) Helicobacter (3) Prion (4) None of these

25.

Nobel prize of 2011 in Physiology or Medicine was awarded for the work on (1) Green fluorescent protein (2) RNA interference (3) Ribosomes (4) Immunity

26.

Antibiotic resistant spores of the following disease were used as Bioweapons or Bioterrorism recently (1) Plague

(2) Rabies

(3) Anthrax

(4) Polio

(4) E. Mayr

32.

(1) Humani Corporis Fabrica

23.

(2) John Ray

(3) Cuvier

A group of related genera are classified as (1) Family (2) Order (3) Class (4) Tribe

The book of Robert Hooke was named as

(3) Systema Naturae

(1) E. Haeckel

31.

(4) None of these. 22.

Biological species concept was given by:

Mark incorrect matching of the term and the taxonomist who coined it (1) Phylum - Cuvier (2) Genus - John Ray (3) Taxonomy - Linnaeus (4) Taxon - Meyer

(1) Biotechnology (2) Genetic engineering

(4) A.R. Wallace

30.

First man made gene Discovery of rDNA

(2) Aristotle

(3) Robert Hook

Identify the correct sequence of taxa of Linnaean hierarchy (1) Phylum, class, family, order and species (2) Phylum, class, order, family and species (3) Class, family, order, species and genus (4) Class, order, genus, species and varieties

Column II

A.

(1) G. L. Cuvier

29.

of study in column II Column I

The foundation of Paleontology was laid down by

THE LIVING WORLD & TAXONOMY 37.

The terms α - taxonomy and β - taxonomy were given by (1) A.P. De Condolle (2) Turrill (3) Julian Huxley (4) Whittaker

38.

Trinomial nomenclature is applicable for (1) Animals only (2) Plants only (3) Both (4) All living organisms

39.

The book ‘Historia Generalis Plantarum’ was written by (1) John Ray (2) Hooker (3) Theophrastus (4) None of these

40.

Cladistics is the system of (1) Cytotaxonomy (2) Phylogenetic classification (3) Numerical taxonomy (4) Biochemical taxonomy

41.

42.

Greek scholars, “A” and Aristotle, arranged animals into four major groups i.e insects, birds, fishes and whales. Here “A” refers to : (1) Carolus Linnaeus (2) Hippocrates (3) Theopharastus (4) Theodosius Dobzhansky Who regarded classification as a subtopic of systematics, dealing with ordering of organisms into groups, and taxonomy as the study of principles and procedures of classification. (1) Adolf Mayer (2) John Ray (3) G. Simpson (4) Carolus Linnaeus

43.

Those species which are morphologically similar but reproductively isolated are known as (1) Cryptic species (2) Jordan’s species (3) Synchronic species (4) Neontological species

44.

Which of the following taxa are not used by botanists? (1) Kingdom & order (2) Phylum & Family (3) Suborder & variety (4) Phylum & sub species

45.

The term taxonomy was proposed by (1) Carolus Linnaeus (2) Takhtajan (3) A.P. de Candolle (4) Julian Huxley

46.

Which of the following is ‘Domain’ taxon. (1) Bacteria (2) Archaebacteria (3) Eubacteria (4) Protista

47.

The name ‘Birds’ and ‘Horses’ taxonomically designate (1) Phylum and Genus (2) Order and genus (3) Class and family (4) Class and species

48.

Mark the odd one in the followings (1) Family (2) Class (3) Taxon (4) Phylum

49.

Practical significance of taxonomy is : (1) Identification of medicinal plant (2) For evolutionary history (3) Identification of unknown living organism (4) None of these

31 50.

Linnaeus is credited for the introduction of : (1) Binomial system of Nomenclature (2) The principle of independent assortment (3) The concept of inheritance of acquired characters (4) The law of limiting factors

51.

Binomial nomenclature system of Linnaeus means that every organism has (1) One name given by two scientists (2) Two names, one Litin and other of a person (3) Two names, one scientific and other popular (4) One scientific name with generic and specific epithet

52.

Among the following categories, the number of common characteristics will be the maximum in (1) Genus (2) Phylum (3) Kingdom (4) Species

53.

International Code of Zoological nomenclature has been published in the following language (1) Greek (2) Latin (3) French (4) All of these

54.

The bracketed key in taxonomic identification provides (1) Sequence of choices between two or more characters (2) Polynomial system of nomenclature (3) Only one pair of contrasting statements (4) Same sequence of characters as in Indented key

55.

The five kingdom classification was proposed by (1) R H Whittaker (2) Carolus Linnaeus (3) Ernst Haeckel (4) Julian Huxley

56.

Linnaean Hierarchy, did not have following taxa (1) Genus and variety (2) Family and Phylum (3) Class and species (4) Species and variety

57.

Which of the following pair is not correctly matched (1) Theory of specieal creation - Father Saurez (2) Typological concept of species - Aristotle & Plato (3) Static concept of species - Lamarck (4) Biological concept of species - Mayr

58.

Two animals which are the members of the same order must also be the members of the same : (1) Class (2) Family (3) Genus (4) Species

59.

Characteristics which define a family are more general than those which define a (1) Species (2) Phylum (3) Class (4) Order

60.

Two species which are morphologically indistinguishable are called (1) Sympatric species (2) Sibling species (3) Allopatric species (4) Monotypic species

32 61.

62.

63.

BIOLOGY Mark the incorrect statement (1) Two generic names can not be similar in any kingdom (2) Species can not be named unless it is assigned to a genus (3) Gender of the specific name follows the gender of the generic name (4) None of these. The system of classification based on the floral structure, root modification and leaf venation etc. is called as (1) Artificial system (2) Natural system (3) Arbitrary system (4) Both (1) and (3)

66.

(1) Ultrasturcture of Nucleus and Nuclear membrane (2) Length and weight of DNA (3) Number of base pairs in DNA (4) Sequence of ribosomal RNA – genes 69.

70.

(1) Cuvier

(2) Lamarck

(3) John Ray

(4) Linnaeus

The ‘Tribe’ category falls between (1) Suborder and Family (2) Genus and Subfamily

(2) All known characters and evidences are taken into consideration

(3) Genus and Species (4) Above family level 71.

(1) Tribe

(2) Variety

(3) Family

(4) Series

The taxon ‘Cohort’ is used in between the following two taxa by Paleontologists (1) Class and Order

(2) Order and Family

(3) Phylum and Class

(4) Kingdom and phylum

Which of the following set of taxa cover greater number of organisms?

In Biosystematics, the basis of classification is (1) Major morphological characters

Which of the following is included in the seven basic categories of the hierarchy?

(2) Cytological characters (3) Evolutionary history considering various parameters from different fields of studies (4) None of these 72.

73.

(1) Phylum and family (2) Family and Order (3) Class and Phylum 74.

The study of principles and procedures of classification is called (1) Systematics

(2) New Systematics

(3) Taxonomy

(4) Nomenclature

The specimen described along with nomenclature type is called (1) Syntype

(2) Holotype

(3) Paratype

(4) Isotype

Who introduced the term ‘Phylum’ in taxonomy

‘Taxonomy without phylogeny may be linked to bones without flesh’ was stated by

(1) L. Cuvier

(2) Lamarck and Treviranus

(1) Engler and Prantl

(2) Takhtajan

(3) R.H. Whittaker

(4) Von Baer

(3) John Ray

(4) Bentham - Hooker

(4) Super Family and Class 67.

The term ‘Family’ was given by

(1) Phylogeny is taken into consideration

(4) Only plants are classified

65.

Carl Woese created 3-domains above kingdom level in hierarchy and also classified kingdoms on the basis of:

In typological concept of classification

(3) Only a few characters are considered 64.

68.

THE LIVING WORLD & TAXONOMY

33

ANSWER KEY EXERCISE 1 : NCERT BASED QUESTIONS

EXERCISE 3 : TEST YOURSELF

1.

(3)

2.

(1)

3.

(3)

4.

(4)

5.

(2)

6.

(3)

7.

(4)

8.

(4)

9.

(1)

10.

(3)

11.

(4)

12.

(1)

13.

(2)

14.

(4)

15.

(4)

16.

(4)

17.

(3)

EXERCISE 2 : WINDOW TO COMPETITIVE EXAMS

1.

(1) Susruta is known as the father of surgery, and Susruta Samhita is considered to be the oldest treatise on surgery.

2.

(2) Control is similar to the main experiment except one variable

3.

(2)

4.

(3) Charles Darwin also discarded the idea of fixity of species.

5.

(4) In biotechnology the useful products are produced by wilful manipulation of mainly micro organism at a molecular level.

6.

(3)

7.

(4) Human can not live in isolation for a long time.

8.

(3) Except one variable, the control experiment is similar to the main experiment.

9.

(4) The discovery of Penicillin by A. Flemming was a case of Serendipity.

10.

(2)

(3)

2.

(2)

3.

(2)

4.

(1)

5.

(4)

6.

(4)

7.

(4)

8.

(4)

9.

(1)

10.

(1)

11.

(3)

12.

(1)

13.

(4)

14.

(2)

15.

(4)

16.

(1)

17.

(4)

18.

(3)

19.

(3)

20.

(2)

21.

(1)

22.

(4)

23.

(1)

24.

(4)

25.

(1)

26.

(2)

27.

(3)

28.

(1)

29.

(1)

30.

(4)

31.

(3)

32.

(3)

33.

(4)

34.

(1)

35.

(2)

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(2)

37.

(3)

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(1)

39.

(2)

40.

(3)

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(3)

42.

(3)

43.

(1)

44.

(3)

45.

(3)

46.

(1)

47.

(3)

48.

(2)

49.

(1)

50.

(3)

51.

(1)

52.

(3)

53.

(2)

54.

(3)

55.

(4)

56. 61.

(4) (2)

57. 62.

(2) (4)

58. 63.

(2) (4)

59. 64.

(1) (2)

60. 65.

(4) (2)

66.

(3)

67.

(1)

68.

(4)

69.

(4)

70.

(3)

11.

(4) Ethnology is the study of human races.

71.

(4)

72.

(3)

73.

(2)

74.

(1)

75.

(2)

12.

(4)

76.

(3)

77.

(2)

78.

(2)

79.

(3)

80.

(2)

13.

81.

(1)

82.

(4)

83.

(2)

84.

(1)

85.

(3)

86.

(4)

87.

(3)

88.

(2)

89.

(4)

90.

(1)

(1) Luc Montagnier et. al were awarded Nobel prize in 2008 for their work on Human Immunodeficiency Virus.

91.

(4)

92.

(2)

93.

(1)

94.

(3)

95.

(3)

14.

(2)

96.

(1)

97.

(4)

98.

(1)

99.

(3)

100. (3)

15.

(4) The most important part experimentation is ‘Control’.

m

y. b

lo

gs

po

t.c

om

1.

of

the

scientific

102. (1)

103. (1)

104. (3)

105. (2)

106. (1)

107. (3)

108. (1)

109. (1)

110. (2)

16.

(2) Big bang theory was given by Abbe Lemaitre.

111.

(4)

112. (4)

113. (2)

114. (4)

115. (1)

17.

(4) 18.

116.

(4)

117. (3)

118. (1)

119. (4)

120. (3)

19.

121. (3)

122. (2)

123. (1)

124. (1)

125. (2)

(3) Leeuwenhoek invented simple microscope and is also known as the father of microbiology.

126. (3)

127. (2)

128. (1)

129. (1)

130. (4)

20.

(2)

131. (2)

132. (1)

133. (2)

134. (3)

135. (3)

21.

136. (4)

137. (4)

138. (4)

139. (1)

140. (1)

141. (3)

142. (4)

143. (3)

144. (3)

145. (1)

(2) In biomedical engineering the spare parts, implants, artificial limbs are produced, or the machines are used for monitoring the health of human.

146. (5)

147. (3)

148. (1)

149. (1)

150. (2)

151. (3)

152. (4)

153. (2)

154. (2)

155. (2)

156. (1)

157. (1)

158. (2)

159. (3)

161. (3)

162. (1)

163. (3)

164. (4)

ht

tp

ic

al

(2)

ed

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s:

160. (1)

ac ad e

101. (1)

22.

(2) Humani Corporis Fabrica is the book of Andreas Vesalius.

23.

(2) William Bateson introduced the term ‘Genetics’. S. Cohen is associated with the discovery of rDNA.

24.

(2)

34

BIOLOGY

25.

(4) B.A. Beutler et. al worked on active and passive immunity for the Nobel prize.

26.

(3) Anthrax is primarily a disease of animals, caused by spore-forming bacterium Bacillus anthracis. (1) Cuvier, known as the father of paleontology, also suggested theory of Catastrophism to explain the origin of life.

27.

28.

(4) According to this concept the members of a species can interbreed among themselves, but remain reproductively isolated from other such groups.

49.

(3) 50.

(1)

51.

(4)

52.

(4) Lower the taxon (category) the more will be the number of common characteristics.

53.

(3) This code of nomenclature has been published in English and French, and uses Latin and Greek words for binomial nomenclature.

54.

(3) Indented key provides sequence of choices between two or more characters.

55.

(1) The 5- kingdoms included Monera, Protista, Fungi, Plantae and Animalia.

29.

(4) Linnaeus in the hierarchy used only 5-taxa. He did not use phylum and family.

56.

(2) He used only 5- taxa in the hierarchy, i.e. Class, Order, Genus, Species and Variety.

30.

(3) The term taxonomy was given by A.P. De Condole.

57.

(3) 58.

31.

(1) The related families are classified in Order.

60.

32.

(3) Phenetic classification is also known as numerical taxonomy.

(2) The species which do not have sub-species are called monotypic species.

61.

(4)

33.

(3) 34.

62.

(4) Such type of classification was used by Linnaeus.

36.

(3) The species distributed in different geographical area are called allopatric. The species of different time period are known as allochronic species.

63.

(3)

64.

(3) The 7- basic categories are Kingdom, Phylum, Class, Order, Family, Genus and Species.

37.

(2) 38.

65.

(1) 66.

40.

(2) Cladistics is the system of classification showing branching due to geographical isolation at different levels.

67.

(1) Lamarck and Treviranus suggested the term ‘Biology’.

41.

(2) 42.

68.

(4) The two domains, Archaea and Bacteria cover two kingdoms, i.e. Archaebacteria and Bacteria.

44.

(4) In place of phylum and sub- species, the botanists use division and variety respectively.

69.

(3) John Ray also introduced the terms species and genus.

45.

(3)

70.

(2) 71.

46.

(1) There are three domains, namely Archaea, bacteria and Eukarya.

72.

(3) Assigning the scientific names to the organisms is called Nomenclature.

47.

(4) Scientific name of horse is Equus caballus while that of ass is Equus hemionus.

73.

(2)

48.

(3) Taxon can be used for any taxonomic rank.

74.

(2) Engler and Prantl used Phylogenetic system of classification for angiosperms.

(1)

(1)

(3)

35.

39.

43.

(3)

(1)

(1)

(1)

59.

(1)

(3)

(3)

Chapter

2

Biological Classification While going through the chapter pay special attention to the following –

   

og

sp



bl

Scientists have classified the organism in different kingdoms at different times. Biological classification was first proposed by Aristotle who used simple morphological characters to classify plants and animals.

y.



(i)

ad

em

Linnaeus initially separated plants and animals in two kingdoms i.e., Kingdom Plantae and Kingdom Animalia. Until recently, it was universally accepted. But later it was found that two-kingdom classification was not sufficient for the following reasons : Prokaryotes and eukaryotes have been grouped together.

ac



Monera



Archaebacteria

om



Methanogens Halophiles Trichomes Diatomite

Bacteria

Cyanobacteria Mycoplasma

Actinomycetes

ot

2. 4. 6. 8.

At a Glance

.c

Terms and definitions – 1. Phylogenetic relationship 3. Thermoacidophiles 5. Colicinogenic factor 7. Heterocyst 9. Capsomeres

e.g., Bacteria and Cyanobacteria were placed under plant kingdom.

ic al

(ii) Heterotrophs and autotrophs were placed together.

e.g., Fungi, which are heterotrophs were placed with plants.

ed

Euglena, has chlorophyll was placed under protozoa, which are heterotrophs.

tm

(iii) It did not differentiate between unicellular and multicellular organisms.

ee

e.g., Protozoans are unicellular organisms, but were placed with multicellular animals.

//n

(iv) Simple organisms were placed with highly complex organisms. e.g., Protozoans were placed with human beings in animal kingdom.

ht tp

s:

Bacteria (prokaryotes) were placed with highly evolved angiosperms in plant kingdom. (v) Unicellular aquatic organisms are difficult to distinguished as plants and animals. 

In three kingdom system, kingdom protista was included along with kingdom plantae and kingdom animalia.



Three kingdom classification was given by Haeckel. They placed all unicellular eukaryotes in protista whether they were plants or animals.



This system was not accepted because it includes both prokaryotic and eukaryotic, chlorophyllous and non-chlorophyllous organisms together.

Protista

   

 

Dino�lagellates Euglenoids

Slime moulds

Protozoa Fungi



    

Chrysophytes ( Diatoms )

Classi�ication of fungi

Plantae

Animalia Viruses Viroids

Lichens

36

BIOLOGY 

Copeland classified organisms into four kingdoms; Monera (all prokaryotes), Protista (unicellular eukaryotes), Metaphyta (multicellular plants) and Metazoa (multicellular eukaryotes).



Most accepted system of classification is five kingdoms classification which was given by Whittaker.

Characteristics of five kingdom system This system was proposed by R.H. Whittaker (1969). Accordingly a separate kingdom has been created for Fungi. Thus, these are – Monera, Protista, Fungi, Plantae and Animalia. The five kingdom classification is based on the following criteria : 

Complexity of cell structure – Prokaryotes or Eukaryotes



Complexity of organisms body – Unicellular or Multicellular



Mode of obtaining nutrition – Autotrophs or Heterotrophs



Phylogenetic relationships

Basic features of all 5 Kingdoms Kingdom 1. Monera (All Prokaryotes)

2. Protista (Protozoans, unicellular algae)

Cellular Organisation Unicellular without nucleus or membranous organelle.

Movement

Nutrition

Reproduction

By flagella (tubulindynein system)

Absorptive or photosynthetic

Asexual

Unicellular eukaryote with nucleus and membranous organelles.

By flagella, Absorptive, cilia, photosynthetic pseudopodia & holozoic and mucilage propulsion

Both sexual and asexual

3. Fungi Multicellular Non-motile (Multicellular eukaryote, no decomposers) plastids, cell walls of cellulose, chitin

Absorptive

Asexual and sexual both

4. Plantae (All plants)

Multicellular eukaryotes of higher organisation, cellulosic cell wall, plastids present

Non-motile

Autotrophic or photosynthetic

Asexual and sexual both

5. Animalia (All animals)

Multicellular eukaryotes of higher organization, no cell wall and chlorophyll.

Highly motile with all type of motile machinery

Holozoic or saprozoic, heterotrophic

Both sexual and asexual but in higher forms only sexual

BIOLOGICAL CLASSIFICATION

37

Connecting Concepts  Phylogenetic Relationships : The earliest living forms produced procaryotic organisms or monerans. They developed chemoheterotrophy, photoautotrophy, anaerobic respiration and aerobic respiration at different times. Monera gave rise to protista, most probably through association of several types of primitive and advanced monerans. There are several types of protista. Fungi, plants and animals have developed from different types of early protistans.

Fig. 2.1 Whittaker’s five kingdoms of life with major groups and

their phylogenetic relationships.

MONERA (KINGDOM OF PROKARYOTES) The kingdom includes all prokaryotes – mycoplasma, bacteria, actinomycetes and cyanobacteria or blue green algae. Characteristics of Monera 

All monerans have evolved from ancient life called progenote. They are most primitive and important decomposers and mineralisers in the biosphere.



They are unicellular/colonial/multicellular with prokaryotic cellular organisation. They are devoid of plastids, mitochondria and advanced (9 + 2) flagella.



They are without nuclear membrane, nucleoplasm and nucleolus.



They reproduce asexually by transverse binary fission or budding.



Protosexual phenomenon is found.



Cell wall contains peptidoglycan (exceptions are archaebacteria and mycoplasma).



These organisms are non-motile or move by beating of simple flagella or by gliding.



They show both autotrophic and heterotrophic mode of nutrition.

38

BIOLOGY Connecting Concepts

Archaebacteria

 Archaebacteria are considered to be  ‘oldest of living fossils’.



 Archaebacteria live under extremely low pH, high temperature, high salinity and high pressure. These properties are  being used in modern biotechnology in a number of fields – (i) Generation of biogas

They are found in most harsh habitats. Such as extreme salty areas (halophiles), hot springs (thermoacidophiles) and marshy areas (methanogens). Their cell wall is adapted to tolerate extreme conditions (peptidoglycan is absent in their wall instead the wall contains protein and non-cellulosic polysaccharides. Pseudomurein are found in some methanogens.



The cell membranes are characterised by the presence of branched chain lipids that makes it highly resistant to heat and low pH.



Three main groups of archaebacteria are :

(ii) Thermophilic enzymes (iii) Restriction enzymes

Archaebacteria is one of the most primitive group of bacteria.

(i)

(iv) Bioleaching of poor mines (v) Biosensors  Bacteria were abundant for over 2 billion years before the appearance of eukaryotes in the world. These were responsible for creating the properties of present atmosphere and soil. Further these bacteria make life on earth possible as they perform integral function as decomposers of organic materials.

Methanogens : These are an anaerobic bacteria and mainly occur in muddy areas and also in stomach of ruminant animals like cattle, where cellulose is fermented by microbes. They produce methane gas (CH4) in bio-gas plants, because they have capacity to produce CH4 from CO2 or formic acid (HCOOH). They are autotrophic which obtain energy as well as carbon for assimilation from end products of decomposition. Typical methods of carbon assimilation are absent.

(ii) Halophiles : These are also anaerobic bacteria, which occur in extreme saline or salty conditions (upto 35% of salt or NaCl in culture medium). Halophiles are able to live comfortably in this high salt concentration because their intracellular salt concentration is equally high. The enzymes and ribosomes of halophiles also function efficiently only at high intracellular salt concentration. A purple pigmented membrane containing bacteriorhodopsin is developed in sunlight in these bacteria, which utilizes light energy for metabolic activities (different from photosynthesis).

 Microorganisms are small-sized microscopic organisms with a size of 1 mm or less. They cannot be observed with the naked eye. Microorganisms belong to several taxonomic groups – viruses, bacteria, algae, fungi, protistans and metazoa.

(iii) Thermoacidophiles : These are aerobic bacteria which are found in hot sulphur springs (upto 80°C). They have the capacity to oxidize sulphur to H2SO4 at high temperature and high acidity (i.e., pH 2.0), hence given the name thermoacidophiles, i.e., temperature and acid loving. Some of these bacteria are able to reduce sulphur to H2S under anaerobic conditions.

Bacteria 

Anton van Leeuwenhoek (1683), a Dutch, observed small or tiny animalcules in sewage water, saliva and tooth scum under his crude microscope and these animalcules were later known as bacteria.



Louis Pasteur gave germ theory of diseases as he reported that certain diseases in plants and animals are caused by bacteria.



Robert Koch first of all cultured bacteria.



John Lister started antiseptic surgery using carbolic acid as disinfectant.



The branch which deals with study of bacteria is known as bacteriology.



Anton van Leeuwenhoek is the father of bacteriology.



The term bacterium (plural-bacteria) was coined by German microbiologist, C.G. Ehrenberg in 1828.



Bacteria are the simplest, most primitive unicellular organisms.



They are found everywhere (air, water, soil, food, inside our body, etc.). They are distinguished by the following characteristics : •

They are prokaryotes. They lack nucleus and other cell organelles of complex cells. Bacteria has prokaryotic ribosome (70 S).

•

Like plants, they possess cell wall. Made up of sugar derivatives which are not present anywhere else, i.e., N-acetyl glucosamine (NAG) and N-acetyl muramic acid (NAM).

BIOLOGICAL CLASSIFICATION



•

They are mostly unicellular but may be in the form of colonies or filaments of independent cells.

•

Each bacterial cell contains a single chromosomes (nuclear material) that is not enclosed in a nuclear membrane. Primitive type of nucleus is present which is known as nucleoid, genophore or incipient nucleus.

39

Besides nuclear DNA, in some bacteria extranuclear or extrachromosomal DNA are present which is known as plasmid. The plasmids are small, circular, double-stranded DNA molecules that are exist separate from genomic chromosome and replicate independently. There are three types of plasmids which are as following : (1) F-factor or fertility factor : It is responsible for transfer of genetic material. (2) R-factor or resistance factor : It provides resistance against drugs. (3) Colicinogenic factor : It produces ‘colicines’ which kill other bacteria. •

Connecting Concepts  In donor cell, F-factor may unite with main genome or nuclear DNA and this donor cell is called Hfr-donor cell (high frequency donor cell) and here transfer of DNA is rapid.

According to shape, bacteria are grouped into four types – Coccus or spherical shaped,  E. coli bacteria is important research bacillus or rod-shaped bacteria, spirillum or spiral/curved shaped bacteria, vibrio or material due to its short life cycle, haploid comma-shaped bacteria. nature and genetic recombinations. The

mechanism of gene action and protein synthesis, regulation of operon model was performed in E.coli.  It is an ideal host in genetic engineering experiments.

Fig. 2.2 Different forms of bacteria



Most bacteria are immotile i.e., they cannot move. However, some bacteria such as bacilli and spirilla can move on their own. Such bacteria can have a single polar flagellum at one end of a cell, or they can have clusters or many flagella at one or both ends.



Bacteria show autotrophic as well as hetero-trophic mode of nutrition.



•

Autotrophic nutrition means synthesis of organic materials from inorganic raw materials with the help of energy obtained from outside sources. It is of two types, chemosynthesis and photosynthesis. The bacteria performing these modes of nutrition are respectively called chemoautotrophs and photo-autotrophs.

•

Photoautotrophic Bacteria : The bacteria possess photosynthetic pigments of two types, bacteriochlorophyll and bacteriophaeophytin.

•

These pigments occur in the membranes of chromatophores dispersed in cytoplasm as chloroplasts are absent.

•

No oxygen is evolved in bacterial photosynthesis. Such type of photosynthesis is known as anoxygenic photosynthesis.

•

Heterotrophic nutrition involves obtaining of readymade organic nutrients from outside sources.

•

Chemoautotrophic Bacteria : The bacteria which are able to manufacture their organic food from inorganic raw materials with the help of energy derived from exergonic chemical reactions involving oxidation of an inorganic substance present in the external medium. The chemical energy obtained from oxidation reaction is trapped in ATP molecules.

Respiration in bacteria can be aerobic in the presence of atmospheric oxygen or anaerobic i.e., in the absence of atmospheric oxygen.

40

BIOLOGY Connecting Concepts



 The bacterial spore or endospore is perhaps the most resistant living structure in biosphere.  Endospore is highly resistant to very high and very low temperature, strong chemicals and acids, etc., due to calcium, dipicolinic acid and peptidoglycan in cell wall. Dipicolinic acid (DPA) helps in stabilizing its proteins. DPA and Ca ions provide resistance to heat.

Bacteria reproduce both asexually as well as sexually. Asexual reproduction in bacteria is by binary fission which takes place in favourable conditions or by endospore formation. True sexual reproduction is absent in bacteria, but there occurs genetic recombination, i.e., bringing together of genetic material of two bacterial cells. There are 3 main methods of genetic recombination : (1) Transformation (2) Transduction (3) Conjugation (1) Transformation : In transformation genetic material of one bacterial cell moves into another bacterial cell by some unknown mechanism and it converts one type of bacterium into another type (Non-capsulated to capsulated form). •

It was first studied by Griffith (1928) in Diplococcus pneumoniae and hence is known as Griffith effect. Later on it was studied in detail by Avery, McCarty and McLeod.

Fig. 2.3 A Typical bacterial cell

(2) Transduction : In this method, genetic material of one bacterial cell goes to other bacterial cell by bacteriophages (viruses which infects bacteria). •

Transduction was first of all reported in Salmonella typhineurium by Zinder and Lederberg (1952).

(3) Conjugation : In conjugation two bacterial cells physically come in contact and genetic material (DNA) of one bacterial cell moves to another cell through conjugation tube which is formed by sex pilli. •

Conjugation was first reported by Lederberg and Tatum (1946) in E. coli bacteria.

•

Conjugation occurs between donor bacterium and recipient bacterium. Donor is having sex pilli and F-factor whereas recipient bacterium is lacking both.



Bacteria have both useful as well as harmful effects.



They play an important role in nitrogen fixation, decay and putrefaction, used in industries, in curdling of milk, setting of fibres, tanning of leather, in production of vitamins, antibiotics and medicines etc.



Bacteria cause harmful diseases in plants, animals and humans. Denitrifying bacteria reduce fertility of soil by converting nitrates into free nitrogen.

BIOLOGICAL CLASSIFICATION

41

Some Common Bacterial Diseases Human Diseases S. No. 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17.

Disease Cholera Typhoid Dysentery Peptic Ulcer Bubonic Plague Bacterial Influenza Whooping Cough Syphilis Gonorrhoea Bacterial Meningitis Vaginitis Tuberculosis (TB) Leprosy Diphtheria Pneumonia Tetanus Boils

Pathogen Vibrio cholerae Salmonella typhosa Shigella dysenteriae Helicobacter pylori Yersinia (= Pasteurella) pestis Haemophilus influenzae Bordetella pertussis Treponema pallidum Neisseria gonorrhoeae Neisseria meningitidis Gardnerella vaginalis Mycobacterium tuberculosis Mycobacterium leprae Corynebacterium diphtheriae Pneumococcus or Streptococcus pneumoniae Clostridium tetani Staphylococcus aureus Animal Diseases

S. No. Disease 1. Anthrax (Cattle, Sheep) 2. Brucellosis (Cattle, Pig, Goat)

Pathogen Bacillus anthracis Brucella melitensis, B. Suis Plant Diseases

S. No. 1. 2. 3. 4. 5. 6.

Disease Soft Rot of Turnip Fire Blight of Apple, Pear Bacterial Blight of Rice Citrus Canker Crown Gall Angular Leaf Spot of Cotton

Pathogen Erwinia carotovora Erwinia amylovora Xanthomonas oryzae Xanthomonas citri Agrobacterium tumefaciens Xanthomonas malvacearum

Cyanobacteria  

 



The new name cyanobacteria has been given to blue green algae or myxophyceae or cyanophyceae class of algae due to their simple prokaryotic organisation like bacteria. The cyanobacteria are the largest and most diverse group of photosynthetic bacteria. There are as many as 2,000 or more cyanobacterial species. The cyanobacteria have chlorophyll-a similar to green plants. Cyanobacteria may be unicellular, colonial or filamentous. Each filament consists of a sheath of mucilage and one or more cellular strands called trichomes. Cyanobacterial cells are larger and more elaborate than bacteria. Cell structure is typically procaryotic – one envelope organisation with peptidoglycan wall, naked DNA, 70S ribosomes and absence of membrane bound structures like endoplasmic reticulum, mitochondria, Golgi bodies, plastids, lysosomes, and vacuoles. Cyanobacteria reproduce by binary fission, budding, fragmentation and multiple fission. Fragmentation of filamentous cyanobacteria can generate small, motile filaments called hormogonia. Some species develop akinetes.

Connecting Concepts  Pasteurization : A process named after scientist Louis Pasteur which uses application of heat to destroy human pathogens in food. In this process poly β-hydroxybutyrate (PHB) is found in several bacteria as reserve food. It can be used to produce biodegradable plastics. Milk is heated at 62.8°C for 30 min or 71.7°C for 15 sec and then immediately cooling it down. This reduces the number of bacteria by killing all non-spore forming bacteria and thus unboiled milk becomes sour earlier than boiled milk.  Lactic acid bacteria unite casein protein of milk in the form of small droplets and form curd and butter.  Waksman was the first person who gave the term antibiotics to the chemical substances which are produced by one micro-organisms and which kill other micro-organisms.  The first antibiotic produced was penicillin (wonder drug) obtained from fungus Penicillium notatum by Sir Alexander Flemming (1923), which checks the growth of Gram +ve bacteria by inhibiting cell wall synthesis or by blocking peptidoglycan synthesis.  The first antibiotic produced from bacteria by Waksman was thiothricin from Bacillus brewis.

42

BIOLOGY Connecting Concepts



 Genetically engineered strain of Pseudomonas putida (superbug) was developed by Dr. Ananda Mohan  Chakraborty (USA) which biodegrade spilled oil.

Heterocyst is a large-sized pale coloured thick-walled cell which occurs in terminal, intercalary or lateral position in filamentous cyanobacteria, e.g., Nostoc. It has enzyme nitrogenase. Heterocyst is specialised to perform nitrogen fixation. About 5–10% cells of a trichome develop into heterocysts, which obtain nutrients from adjacent vegetative cells and contribute fixed nitrogen in the form of amino acid glutamine.

 Mycoplasma are insensitive to  Cyanobacteria form symbiotic associations with other organisms. They are photosynthetic penicillin and can be killed by using partners in many lichens, protozoa, liverworts, mosses, gymnosperms and angiosperms. chloramphenicol, streptomycin and erythromycin. Mycoplasma



Mycoplasma are the smallest known aerobic prokaryotes without cell wall. The smallest cell so far discovered is of Mycoplasma gallisepticum having a diameter of 0.1 µ.



Mycoplasma have been reported to cause a number of plants and animal diseases and these have also been reported from urinogenital tract of human beings.



They lacks cell wall. They have typical colonial appearance and filter through 450 nm bacterial filters.



As mycoplasma have no cell wall, hence have no definite shape, i.e., pleomorphic and thus are called Jokers of microbiology. The structure of mycoplasma varies species to species. They are filament form or coccus (round) form.



On outer side, they have tripartite (3 layered) cell membrane made of lipoproteins.



In human beings, Mycoplasma hominis causes pleuropneumonia, infertility in man and inflammation in genitals. Mycoplasma pneumoniae causes Primary Atypical Pneumonia (PAP). Arthritis, respiratory infections and rheumatism are also caused by mycoplasma.



In plants important diseases caused by Mycoplasma are : 1. 3. 5. 7.

Little leaf of brinjal. Bunchy top of papaya. Mulberry dwarf. Potato witche’s broom.

2. 4. 6.

Clover dwarf. Maize stunt. Aster yellows.

Actinomycetes 

These are filamentous bacteria (like moulds or fungi).



These are generally present as decomposers in soil. They reproduce asexually by means of conidia produced at tips of filaments.



Most of these secrete chemical substances having antimicrobial activities called antibiotics e.g., Streptomyces species secrete streptomycin, neomycin, chloromycetin, terramycin, erythromycin, etc.

PROTISTA (KINGDOM OF UNICELLULAR EUKARYOTES) Haeckel (1886) created the kingdom protista to include all unicellular eukaryotic microorganisms. Phylogenetically protists link the prokaryotic kingdom monera with multicellular kingdoms of fungi, plantae and animalia. 

Protists have a typical eukaryotic structure with membrane bound organelles and nucleus.



Protists are classified into photosynthetic protists slime moulds and protozoan protists.



Mesokaryotic conditions of nucleus are found in dinoflagellates.



Locomotion is by flagella (Euglena ( ), cilia (Paramoecium ( ) and pseudopodia (Amoeba, ( slime moulds) and mucilage propulsion (diatoms move from one place to another by the secretion of mucilage). Protists like sporozoans and non-flagellate euglenoids move by wriggling.



Flagellate structure possess (9 + 2) microtubular arrangement.

BIOLOGICAL CLASSIFICATION 

Protists may be photosynthetic, heterotrophic or mixotrophic (Euglena).

Chrysophytes 

They are a group of diatoms or golden algae (Triceratium, Pieurosigma, Navicula, Cymbella, Amphipleura) and golden brown photosynthetic microscopic protists. They are basically unicellular but can form pseudofilaments and colonies.



Diatoms occur in aquatic and moist terrestrial habitat. Diatoms are very good pollution indicators.



The body is covered by a transparent siliceous shell. (silica deposited in cell wall) known as frustule. The frustule is made of two valves, epitheca and hypotheca.



Diatoms are microscopic unicells of various shapes, viz., circles, semicircles, rectangular, triangular, spindle shaped, boat-shaped, etc. Cells may form zigzag (e.g., Diatoma), stellate or fan-shaped colonies. Incipient filaments occur in Melosira.



Depending upon the symmetry, diatoms are of two types— pennate (bilateral symmetry, e.g., Pinnularia, Navicula) and centric (radial symmetry, e.g., Melosira).



They are photosynthetic. They have chlorophyll – a, chlorophyll – c, α– carotenoids and fucoxanthin (gives brown colour) pigments.



Each cell has a large central vacuole. The food reserves are oils and leucosin (polysaccharide). Volutin globules which are proteinaceous in nature also occur.



Flagella do not occur in somatic cells. However, some diatoms are able to glide by secreting mucilage. Mucilage and oil globules also help the planktonic forms to remain afloat over the surface of water.



The common mode of multiplication is by binary fission. Sexual reproduction varies from isogamy to oogamy. Fertilization produces a zygote which grows in size and forms a rejuvenescent cell called auxospore.



The siliceous cell of diatoms do not decay easily. They pile up at the bottom of water reservoirs and form big heaps called diatomite or diatomaceous earth or kieselguhr.

Economic importance of diatoms 

Diatoms are important sources of food to aquatic animals.



The oils extracted from some fishes and whales are actually produced by diatoms.



Diatomite deposits are often accompanied by petroleum fields.



Diatomite is porous and chemically inert. It is, therefore, used in filtration of sugar, alcohols and antibiotics.



Diatomite is employed as a cleaning agent in tooth pastes and metal polishes.



Diatomite is added to paints for enhancing night visibility.



Diatomite is employed as insulation material in refrigerators, boilers and furnaces.



Diatomaceous earth is used to make sound proof rooms.

43

44

BIOLOGY Check Point

Write the causative agent of the following diseases : (i) Bunchy top of papaya. (ii) Diphtheria (iii) Citrus canker (iv) Syphilis (v) Bubonic plague

Dinoflagellates 

Dinoflagellate are biflagellate, unicellular golden brown photosynthetic protists which are mainly marine.



They appear yellow, green, brown, blue or red depending on the pigments present in their cells.



The cell wall has stiff cellulose plates on the outer surface.



The dinoflagellate nucleus is very distinctive as it has unusual combination of prokaryotic and eukaryotic characteristics. It is described as mesokaryon and has permanently condensed chromosomes. Some species of dinoflagellates have non-condensed chromosomes at some stages in their life cycle.



Chromosomes are generally membrane attached and nuclear membrane remain intact during mitosis.



Most of them have two flagella; one lies longitudinally and the other transversely in a furrow between the wall plates.



Many species of dinoflagellates posses light sensitive organelles known as eye spot. Some of them are mere collections of carotenoid containing lipid globules while others have membrane also. It has a pigmented region and a lens like refractive portion.



Very often, red dinoflagellates (e.g., Gonyaulax) undergo such rapid multiplication that they make the sea appear red.



Dinoflagellates exhibit the phenomenon of bioluminescence which is emission of light by living beings. 18 genus of dinoflagellates emit light. They make body glow in dark e.g., Gonyaulax, Noctiluca, Ceratium, Peridinium.



Toxins released by them may even kill other marine animals such as fishes.



Sometimes they do not kill the animals but accumulate in body of animals like shell fish. Eating such poisoned shell fish causes fatal paralysis in human beings. It affects the neuromuscular transmission and known as paralytic shell-fish poisoning or P.S.P.

Euglenoids 

It includes Euglena-like flagellates which have plant like characteristics (chlorophyll) in addition to some animal characteristics. They ingest food particles and carry out photosynthesis.



Mostly unicellular and free living, found in fresh water ponds, ditches or in damp soil.



Instead of a cell wall, they have a protein rich layer called pellicle which makes their body flexible. Though they are photosynthetic in the presence of sunlight, when deprived of sunlight they behave like heterotrophs by predating on other smaller organisms. Example : Euglena.

Photoreceptor

Contractile vacuole Flagellum Nucleus

Fig. 2.4 Euglena

BIOLOGICAL CLASSIFICATION 

They have ‘two’ tinsel flagella. One is usually reduced. A single long flagellum seems to have two branches at the base with each of which having its own basal granule.



Euglenoids swim actively in a liquid medium with the help of their long flagellum.



They can also perform creeping movements by expansion and contraction of their body, the phenomenon is called metaboly or euglenoid movements.



The base of flagellum bears a swelling called paraflagellar body. A stigma occurs attached at the level of paraflagellar body. Both acts as photoreceptor.



An osmoregulatory contractile vacuole is found.



Nutrition is holophytic (photoautotrophic), saprobic (e.g., Rhabdomonas) or holozoic (e.g., Peranema). Even holophytic forms can pick up organic compounds from the outside medium. Such a mode of nutrition is called mixotrophic (e.g., holophytic + saprobic).



The photoautotrophs or holophytic forms possess chloroplasts with or without pyrenoids (proteinaceous bodies).



Store carbohydrates as paramylum bodies.



Sometimes, usually under unfavourable conditions, some Euglenae come close together, secrete gelatinous covering within which they remain embedded. This condition is called palmella stage. On return of favourable conditions, they regenerate their flagella and start their normal life.

Slime Moulds 

They constitute a group of consumer-decomposer organisms which live on decaying organic matter in both terrestrial and aquatic habitats.



They are unicellular, saprophytic organism which lack cell walls and have the plasma membrane as their outer covering.



They move through pseudopodia.



The cellular forms are called plasmodium while the acellular forms are called pseudoplasmodium. They have numerous diploid nuclei.



Their spores having cell wall are produced by reduction division. The spores acts as gametes and are known as myxamoebae or swarm cells. The zygote undergoes free nuclear division to produce the multinucleate slime mould.



Slime moulds consist of a spreading slimy mass of protoplasm and share the characters of both animals and fungi. Due to this peculiarity they are commonly called fungus animal. Slime moulds are of two types - acellular slime moulds and cellular slime moulds. Acellular Slime Moulds (i) These slime moulds have a free living diploid somatic phase of one large mass of protoplasm in which there may be thousands of nuclei, lacking cell walls. (ii) It often appears as a slimy, fan shaped network of living matter. It is called as plasmodium. (iii) This mass flows along in an amoeboid manner on the soil of forest, surface of dead leaves or on a rotting log. As it moves along it engulfs food particles and digests them in food vacuoles. (iv) Examples of acellular slime moulds Physarum, Physarella, Fuligo, Dictydium, Lycogala, Tubifera. Cellular Slime Mould (i) They are characterised by the absence of flagellate cells, formation of pseudoplasmodium, absence of a sporangial cover, presence of cellulose wall around spores and anisogamous type of sexual reproduction. (ii) In cellular slime moulds numerous individuals, amoeboid cells aggregate and move together like a mass of protoplasm. This is called as a pseudoplasmodium since individuals are not fused.

45

46

BIOLOGY Connecting Concepts

PROTOZOA

 Diseases caused by zooflagellates  are as following :

Classification of Protozoa is mainly based on locomotory organelles. Protistan protozoa are divisible into four major groups – zooflagellata, sarcodina, sporozoa and ciliata. 1. Central african sleeping sickness or Zooflagellates Gambian is caused by Trypanosoma gambiense. Vector is Tsetsefly Glossinapalpalis while east african sleeping sickness or rhodesian is caused by Trypanosoma rhodesiense. It is also known as trypanosomiasis. It is transmitted by Glossina morsitans Trypansoma cruzi cause chages disease or american trypansomiasis. 2. Giardia lamblia or Giardia intestinalis is popularly known as grand old man of intestine causes giardiasis or black packer’s disease.

They are protozoan protists which possess one to several flagella for locomotion. Zooflagellates are generally uninucleate, occasionally multinucleate. The body is covered by a firm pellicle. Cyst formation is also present. • Examples of zooflagellates: Trichonympha, Lophomonas, Giardia, Trypanosoma, Leishmania and Trichomonas. Trichonympha and Lophomonas are cellulose digesting symbionts in the body of termites. Sarcodines • •

• •

They develop pseudopodia for locomotion and ingestion of food. Pseudopodia are temporary protoplasmic outgrowths. Sarcodines are generally uninucleate, occasionally multinucleate. The body is without periplast (with a covering of only plasmalemma) or have a shell.

3. Kala-azar, dumdum fever or visceral Examples of sarcodines : • Entamoeba histolytica – human parasite that resides in the upper part of large intestine leishmaniasis is caused by Leishmania and causes the disease known as amoebic dysentery or amoebiasis. donovani. Its vector is blood sucking sandfly Phlebotomus. • Entamoeba coli – It inhabits human colon. It is commensal parasite and does not 4. Leishmania tropica causes dermal or skin leishmaniasis, also called oriental sore or Delhi sore (= Delhi boil). Leishmania brasiliensis produces mucocutaneous leishmaniasis or expundia.

produce any disease. Entamoeba gingivalis or mouth Amoeba – It is found in tartar of teeth and in pus pockets of bleeding gums. The condition is called as pyorrhoea. Sporozoan •

• • •

They are develop from paristic mode of life (usually endoparasites). Locomotory organs (cilia, flagella, pseudopodia etc.) are absent. The body is covered by elastic pellicle or cuticle and have a single nucleus, contractile vacuoles are absent. Sporozoans forms occasionally Amoeba like stages.

•

Plasmodium falciparum – causes malignant tertian fever or cerebral malaria or pernicious malaria or black-water fever. Plasmodium ovale – causes benign tertian fever.

5. Polymorphism in Trypanosoma. Trypanosoma has four forms. Three of them are developmental stages, viz., • crithidia, leptomonas and leishmania. Infective or metacyclic stage is Examples of sprozoan : trypanosoma. In human blood, the • Plasmodium vivax – causes benign tertian fever. adult or trypanosoma type occurs.  Plasmodium is digenetic, that is, with two hosts, human beings and females of mosquito Anopheles. Female Anopheles is the primary host as sexual reproduction occurs in it. Human being is secondary host. Monkey is reservoir host.

• Ciliates • • • •

• • • • •

They are protistan protozoans which possess cilia as organelles of locomotion and food capturing. Ciliates are mostly free living fresh water protistans. A few are marine. Some are parasites. Free living forms are generally motile. A few are sedentary (e.g., Vorticella). Though unicellular, ciliates have the highest degree of structural and physiological complexity due to specialisation of organelles for skin, muscles, sense organs, kidney, ingestion, egestion, etc. Food collecting apparatus consists of an oral groove, vestibule, buccal cavity, cytostome and cytopharynx. A cytopyge or cytoproct is also formed for egestion. Two types of nuclei are found, larger metabolism controlling polyploid macronucleus and smaller heredity controlling diploid micronucleus. Asexual reproduction occurs by binary fission, budding and cyst formation. Sexual reproduction by conjugation. Autogamy also occurs. Examples Paramoecium, Tetrahymena, Vorticella, Balantidium. Tetrahymena is used in biological research. Balantidium coli causes balantidial or ciliary dysentery in humans. Infection comes from faecal contamination of pig.

BIOLOGICAL CLASSIFICATION

47

FUNGI (KINGDOM OF MULTICELLULAR DECOMPOSERS) Fungi are achlorophyllous, heterotrophic, gametophytic, haploid, multicellular, eukaryotic nucleated, spore producing thallophytes which are surrounded by cell wall of chitin (fungus cellulose).  The fungi were given the status of kingdom by R.H. Whittaker (1969) in his five kingdom system of classification.  Study of fungi is called Mycology or mycetology.  Pier Antonio Micheli an ltalian Botanist is regarded as father of mycology. He wrote Nova Genera Plantarum.  E. J. Butler is regarded as father of Indian Mycology and Phytopathology.

Agaricus Alternaria Saccharomyces

Penicillium

Aspergillus

Rhizopus Polyporus

Mucor Fig. 2.5 Some Fungi

Peziza

Penicillium

General Characters  Fungi are non vascular, non-seeded, non-flowering, multicellular decomposers and mineralisers of organic wastes and help in recycling of matter in the biosphere.  In true fungi the plant body is thallus. It may be non-mycelial or mycelial. • Non Mycelial : The non-mycelial forms are unicellular; however they may form a pseudomycelium by budding. e.g., Yeast. • Mycelial : In mycelial form plant body is made up of thread like structures called hyphae. Hyphae are usually branched tube like structure bounded by a cell-wall of chitin. The hyphae may be septate (higher fungi) or aseptate (lower fungi). • Septate hyphae may be of 3 kinds, uninucleate (monokaryotic hyphae), (dikaryotic hyphae) with binucleate cells or multinucleate. Some fungi are aseptate and known as coenocytic fungi, with hundreds of nuclei in continuous cytoplasmic mass.  The cell shows eukaryotic organization but lack chloroplast and Golgi bodies. The genetic material is DNA and mitosis is intracellular (karyochorisis).  Fungi lack chlorophyll, hence, they do not prepare food by photosynthesis. Thus they can grow where, organic material is available.  Fungi are heterotrophs that acquire their nutrient by absorption. They store their food in the form of glycogen.  The primitive fungi have oogamous type of sexual reproduction where as most advanced ones do not have sexual reproduction.  Fungi are achlorophyllus organisms and hence they live as heterotrophs i.e., as parasites and saprophytes. • Parasites : They obtain their food from a living host. Usually some of their hyphae modified into haustoria. •

Saprophytes : They derive their food from dead and decaying organic matter.

Connecting Concepts  Roman emperor Caesar was poisoned by his wife by Amanita caesarea.  In karyochorisis nuclear division involves formation of internal spindle. The latter may be connected with centrioles or spindle pole bodies or SPB. Nuclear envelope persists during nuclear division.  Obligate parasites : They thrive on a living host throughtout their life and with the death of host, parasitic fungi dies. Eg., Puccinia.  Facultative parasites : Fungi which lives independent of a host but may occasionally be parasitic under certain conditions. Eg., Fusarium.  Ectoparasites or ectophytic parasites : They grow on the surface of host cells and absorb their food through haustoria.  Endoparasites or endophytic parasites : They enter into the tissues of the host.

48

BIOLOGY •

Connecting Concepts  Obligate saprophytes : They can not live without dead organic matter.  Facultative saprophytes : Some fungi which are usually parasitic but after the death of host plant, are able to absorb their food from the decaying body of the plant.  Predaceous fungi : Some fungi e.g., Dactylella derive their food from protozoans, eelworms and rotifers.  Heterothallism (GK. heteros – different, thallos – undifferentiated body) is the phenomenon in which the fusing gametes belong to two genetically distinct strains of the same species though there may not be any morphological distinction between the gametes or structures bearing them. It was first discovered by Blakeslee in 1904. Since, there is no morphological distinction between the different strains producing compatible gametangia, they are called (+) and (–), A and B or a and α. Heterothallism is a mechanism to introduces variations that are helpful in adapting to diverse habitats, unfavourable environments and toxic chemicals.

Symbionts : Some fungi live symbiotically with algae (in lichens). Some fungi live in the roots of higher plants e.g., in the roots of Pinus. This type of symbiotic relationship is called mycorrhiza.  Some fungi may grow on cow dung (coprophilous fungi). Reproduction Fungi have three types of reproduction. • Vegetative Reproduction : Vegetative reproduction in fungi may be of the following types: (a) Fragmentation : Multiplication by breakage of mycelium. (b) Fission : Simple splitting of vegetative cells into two daughter cells. (c) Budding : Some fungi produce small outgrowths i.e., buds from their vegetative body. Eventually the buds are cut off to form new individuals. (d) Oidium formation : In some fungi the hyphae break up into numerous small fragments known as Oidia and give rise to new hyphae. (e) Chlamydospore : Under unfavourable conditions, the hypha forms thick walled resting resistant spores which on return of favourable conditions germinate to give rise to new individuals. Thus, chlamydospore are organs of perennation.

Fig. 2.6 Mycelium of fungus with septate hypa & mycelium

of fungus with aseptate hypa

Fig. 2.7 Vegetative reproduction in Fungi

BIOLOGICAL CLASSIFICATION

49

Asexual Reproduction Asexual reproduction in fungi may be of the following types: (a) Zoospore formation : Zoospores are thin walled uninucleate, motile structures formed in zoosporangia. They may be uniflagellate (e.g., Synchytrium) or biflagellate (e.g., Saprolegenia). (b) Sporangiospores : They are nonflagellate spores that develop inside sporangia, e.g., Mucor, Rhizopus. Sporangiospores are usually dispersed by air currents. Therefore, they are produced in large numbers. (c) Conidia: Conidia are non-motile, thin walled exogenous spores produced on a conidiophore. They are arranged in chains on the conidiophore e.g., Aspergillus and Penicillium. They may also be produced singly on a conidiophore e.g., Pythium. Sexual Reproduction Sexual reproduction is reduced in fungi and take place by two fusing gametes. It includes 3 stages: (a) Plasmogamy or fusion of two protoplasts (b) Karyogamy or fusion of two nuclei (c) Meiosis or reduction division In higher fungi, kayrogamy is delayed and occurs just before meiosis. In the stage intervening between plasmogamy and karyogamy the cells often contain two nuclei or dikaryons (n + n). Such cells are called dikaryotic cells. The phase is known as dikaryophase. Sexual reproduction of fungi is of the following types : (i)

Planogametic copulation : In this process, fusion of two gametes of opposite sex or strains takes place. This process is usually of two types i.e., isogamy and heterogamy.

(ii) Gametangial contact: In this process, two gametangia come in contact with one another. Both the gametangia never fuse together loosing their identity. (iii) Gametangial copulation: In this process, entire content of 2 gametangia is fused. (iv) Spermatization: The uninucleate, nonmotile male gamete called spermatia is transferred to trichogyne of ascogonium (female gametangium). The contents migrate into receptive structure and dikaryotic condition is established. (v) Somatogamy: This takes place in fungi where formation of gametes is absent. Here two hyphae of opposite strains are involved in fusion thus bringing about dikaryotisation.

Classification of Fungi A number of criteria are used for classifying fungi. The important ones are: (a)

Morphology of mycelium and reproductive structure. Reproductive structure is more important as it exhibit more variation.

(b)

Types of spores and their dispersal.

(c)

Life cycle.

Kingdom fungi has been divided into two divisions Division 1: Myxomycotina e.g.: Slime moulds. No cell wall. Division 2: Eumycotina. They are true fungi, cell wall is present. This subdivision has been divided into following 4 classes. Classes: • Phycomycetes • Ascomycetes • Basidiomycetes • Deuteromycetes

Fig. 2.8 Different types of sexual reproduction in fungi

50

BIOLOGY

Phycomycetes (Algal fungi)  

These are aseptate, coenocytic fungus. Asexual reproduction takes place by zoospores (motile) or by aplanospores (nonmotile). These spores are endogeneously produced in sporangium. Sexual reproduction occurs by gametangial copulation (conjugation) between two similar, multinucleated coenogametangia containing multinucleated coenogametes to produce zygospore (sexual spore). Some common examples are Mucor, Rhizopus (bread mould) and Albugo (parasitic fungi).

Ascomycetes (Sac fungi)   

 Connecting Concepts



 ‘Guinea Pig’ of Plant Kingdom. Aspergillus flavus. ‘Drosophila’ of plant  Kingdom. Neurospora.

Mycelium is branched, septate (except yeast which is unicellular). Each cell of mycelium is uninucleated (e.g., Penicillium) or bi-nucleated or multi-nucleated, cell wall is made up of fungus cellulose (chitin). Flagella totally absent, asexual reproduction by conidia produced exogenously on branched/ unbranched conidiophore; conidia are brown/green/blue/yellow/pink and provide colour to the mycelium. Sexual spores are ascospores which are produced endogenously in sac like asci (singular ascus). These asci are arranged in different types of fruiting bodies called ascocarps. Ascomycetes include unicellular yeast (Saccharomyces), ), blue mould ((Aspergillus), green mould ((Penicillium), pink mould ((Neurospora), parasitic fungi such as Erysiphe which causes powdery mildews, Claviceps purpurea which causes ergot of rye. Neurospora is used extensively in biochemical and genetic work.

 Biobleaching. Fungus Phanerochaele Basidiomycetes (Club Fungi) chrysosporium can bleach paper pulp  Class basidiomycetes include Agaricus (mushroom), Puccinia (rusts) and Ustilago (smuts). better than bleaching powder.

    



It is commonly called club fungi because the basidia are club shaped. These are most evolved, most complex and most advanced fungi and best decomposers of wood. These are most commonly seen fungi as their fruiting bodies are large and easily visible e.g., mushrooms, puff ball, rusts, smuts and predaceous fungi do not produce fruiting bodies. The mycelium is branched and septate. The asexual reproduction are generally absent, but vegetative reproduction by fragmentation is common. The sex organs are absent, but plasmogamy is brought about by fusion of two vegetative or somatic cells of different strains or genotypes. The resultant structure is dikaryotic which ultimately gives rise to basidium. Karyogamy and meiosis take place in the basidium producing four basidiospores. The basidiospores are exogenously produced on the basidium (Pl. :basidia). The basidia are arranged in fruiting bodies called basidiocarps. Some common members are Agaricus (mushroom), Ustilago (smut) and Puccinia (rust fungus).

Deuteromycetes (Fungi imperfecti)   



The perfect stage (sexual stage) is either absent or not reported and hence called fungi imperfecti. Some members are saprophytes or parasites while a large number of them are decomposers of litter and help in mineral cycling. Mycelium is septate, branched. Asexual reproduction by conidia produced on conidiophores. These conidiophores may occur isolated or aggregated to form complex structures like acervulus, synnema, sporodochium and pycnidium. Acervulus (called asexual fruitification) is a aggregation of hyphae developed beneath the surface of host plant. These hyphae produce short conidiophores packed closely to form a flat bed like mass on the surface of host conidia are not covered by fungal tissue.

BIOLOGICAL CLASSIFICATION 

Conidiophores are free from each other and bear conidia e.g., Colletotrichum.



Some examples are Alternaria, Colletotrichum and Trichoderma.

PLANTAE (KINGDOM OF PLANTS) 

Members are multicellular, eukaryotic, photosynthetic organisms. Main characters of the members of this kingdom are : •

Cellulosic cell wall.

•

Non-motile, excepts some aquatic forms.

•

Presence of chloroplasts.

•

Photosynthetic mode of nutrition (oxygenic photosynthesis), e.g., different types of algae (green, brown, red algae), bryophytes, pteridophytes, gymnosperms and angiosperms.

•

Growth is usually indefinite.

•

Some of the plants are heterotrophic. They are mostly parasitic. A few are saprobes. A small group of autotrophic plants catch small animals and insects for obtaining nitrogen. They are called carnivorous or insectivorous plants.

•

Reproduction is both asexual and sexual. Accessory spores are present in lower plants. An embryo stage is absent in the algal group but present in others.

ANIMALIA (KINGDOM OF ANIMALS) 

These are multicellular eukaryotic organisms.



The cells do not contain cell wall, but contain only cell membrane.



They do not perform photosynthesis and have heterotrophic nutrition.



They have the power of locomotion.



They show increased sensitivity through the nervous system.

VIRUSES 

Study of virus – virology.



The term ‘virus’ has been derived from latin, which means poison or venom or viscous fluid.



These are defined as, infectious nucleo-proteins.



These are submicroscopic organisms generally less than 200 mµ.



They are obligate parasites, i.e., can live inside living host only.



Ivanowsky (1892) recognised certain microbes as causal organism of the mosaic disease of tobacco. These were found to be smaller than bacteria because they passed through bacteria-proof filters.



M.W. Beijerinek (1898) demonstrated that the extract of the infected plants of tobacco could cause infection in healthy plants and called the fluid as Contagium vivum fluidum (infectious living fluid).



W.M. Stanley (1935) showed that viruses could be crystallised. They are inert outside their specific host cell.



They have either RNA or DNA.

51

52

BIOLOGY Check Point

Give the scientific term for (a) A cell with two haploid nuclei of different mating types. (b) The symbiotic association of a fungus with the root of higher plant. (c) Fruiting body of ascomycetes. (d) Uninucleate non motile gamete transferred to female gametangium. (e) Aggregration of hypae developed beneath the surface of host plant produces conidia without fungal covering.



They have characteristic mode of multiplication, i.e., once a virus enters into the host cell, it takes control of whole biochemical machinery of host cell and orders the metabolic machinery to synthesize their own (viral) components.



They have character of both living and non-living.



Non-living characters of virus





•

No protoplasm

•

No enzyme system

•

No respiration

•

They can be crystallized

•

Do not grow in culture medium

Living characters of virus •

They contain nucleic acid as a result of which they are capable of synthesizing proteins.

•

They can multiply inside living host cell.

•

They cause disease in humans, plants and animals.

Bacteriophage : Bacterial viruses or bacteriophages (viruses that infect the bacteria) are usually double stranded DNA viruses.

Types of bacteriophages Broadly of two types : 1.

Prophages or non-virulent phages or non-infective phages : The phages which do not cause lysis of bacteria soon after their formation inside the bacterial cell are called prophages. Such bacterial cells which are having prophages inside them are called Lysogenic bacteria.

2.

Virulent phages or infective phages : The phages which cause lysis of bacterial cell at once are called virulent phages. Most studied series of bacteriophages is T-series, i.e., T2, T4, T6, etc.

Structure of bacteriophages 

Having tadpole-like structure, i.e., with head and tail. Nucleic acid generally DNA is present inside the head. Head (DNA covered with protein coat) Collar Neck Tail Tail fibres

End plate Fig. 2.9 Structure of bacteriophage



Head is hexagonal having length 950Å and breadth 650Å. Tail is joined to head by neck and collar.



Tail is having hollow core and is surrounded by tail sheath. At the end of tail, end plate is present to which tail fibres are attached.

BIOLOGICAL CLASSIFICATION Multiplication Viruses multiply by lytic or lysogenic cycle. Lytic Cycle The main steps of lytic cycle are : 1. Adsorption : Bacteriophage is attached to bacterial cell surface with the help of tail fibres. 2. Penetration : Only nucleic acid of phage enters into the bacterial cell through the lysis of bacterial cell by lysozyme secreted by tail fibres. Protein coat is left outside, which is known as ghost or doughnut. 3. Virus nucleic acid control the metabolic activities of bacterial cell and forms new phage components, which unite to form 100-300 new phages with 15-20 minutes. 4. Lysis of bacterial cell to release new phages.

Fig. 2.10 Lytic cycle of T2 Bacteriophage

Lysogenic cycle It is a mode of viral multiplication in which the virus does not cause immediate lysis of the host cell nor produce phage particles immediately. It has following stages.

53

54

BIOLOGY Check Point

Fill in the blanks : (1) The phages which do not cause lysis of bacteria soon after their formation inside the bacterial cell is known as ________. (2) Virus which attack bacteria are called as ________. (3) ________ is the protein covering of TMV. (4) AIDS virus contains ________. (5) The integrated viral genome is called ________.

(i)

Entry of viral genome in bacterial cells : The virus attaches to the surface of host cell. The viral genetic material passes into the host by the help of lysozyme.

(ii)

Formation of prophage : The virus genome produces a repressor and an integrase. The repressor does not allow the viral genome to take over the metabolic machinery of the host cell. Enzyme integrase fuses the viral genome with DNA of the host cell at a specific site. The integrated viral genome is called prophage or provirus. In this state the virus remains non-virulent. It is also called temperate stage.

(iii) Lysogeny : The condition of host cell carrying a prophage is called lysogeny. The prophage multiplies along with the multiplication of the host cell without harming the latter. This mode of multiplication is called lysogenic cycle. (iv) Conversion into lytic phage : Occasionally, repressor formation is inhibited. Certain physical factors (e.g. UV radiations), chemicals (e.g., nitrogen gas, mustard gas) and stresses inhibit its formation. The viral genome separates from the genome of the host cell and becomes virulent or lytic. It takes over the machinery of the host cell, undergoes replication and forms viral proteins and assemble virus particles. The host cell undergoes lysis to liberate the virus particles.

om

 The inert particle of virus, outside its host, is called virion. Importance of bacteriophages 1. Used in studying viral infection mechanism. 2. Used in control of certain bacterial diseases (as phages are very specific in relation to their host). 3. Purity of holy Ganges is due to presence of bacteriophages. TMV (Tobacco Mosaic Virus) : It is a rod-shaped virus. The rod has a core which contains helically coiled single stranded RNA .



There is a protective covering of protein called capsid around the infective part. Capsid consists of 2130 subunits called capsomeres and has antigenic property.



TMV causes mosaic disease to tobacco leaves and some other plants.



There is loss of chlorophyll in young leaves. Later on non-green and green patches are found on mature leaves as well. Green areas grow in thickness and give blistered appearance.



The infected leaves also show curling and distortions.

y.

bl

og

sp

ot

.c



em

HIV (Human Immunodeficiency virus, AIDS virus) It is round retrovirus of about 100 nm in diameter.



The surface is covered by host derived envelope which bears spikes which have protein components known as peplomers complementary to CD4 or T4 antigen receptor present on the surface of helper T-cells, monocytes, macrophages, etc.



Inner to envelope, viral wall is present which is made of two layers.



The core contains two single strands of genomic RNA, protein, reverse transcriptase enzyme etc.

la c

ca

HIV causes AIDS for which no remedy has been found. Generally in plant viruses, RNA is present but in cauliflower mosaic virus, DNA is present.

ee tm



ed i



ad



ht

tp

s:

//n



Generally in animal viruses, DNA is present but in following animal viruses, RNA is present: (i) Influenza virus : Single stranded RNA. (ii) Rous sarcoma virus : Single stranded RNA. (iii) AIDS virus : Single stranded RNA. (iv) Poliomyelitis virus : Single stranded RNA. (v) Reovirus : Double stranded RNA.

BIOLOGICAL CLASSIFICATION 

Single stranded RNA viruses (e.g., AIDS virus) which carry reverse transcriptase enzyme (which copies RNA into DNA, i.e., reverse transcription), are called retroviruses.



In bacteriophages, generally DNA is present but in MS2, F2, r-17 bacteriophages, RNA is present.



Generally DNA is double stranded but in φ 174 bacteriophage and S/3. E. coli phage, DNA is single stranded.



Generally RNA is single stranded but in reoviruses, wound tumour viruses and rice dwarf virus, RNA is double stranded.



Total number of genes is about a hundred for a large virus, e.g., Vaccinia (cowpox virus) or 3 or 4 for the smallest virus.



In some mammalian viruses, outside the capsid there is another membrane which is known as limiting membrane or mantle.



Coliphage is the virus infecting E. coli bacteria (discovered by F.H.d’ Herelle).



Cyanophages are viruses infecting blue-green algae or cyanophyceae or cyanobacteria. (The first cyanophage or algal virus was discovered and isolated from 3 blue-green algal genera: Lyngbya, Phormedium and Plectonema, hence called LPP-l).



Safferman and Morris (1963) discovered cyanophages and these are having double stranded DNA.



Viruses infecting fungi are called mycophages. Mycophages were first of all discovered by Sinden (1957) in Agaricus bisporus. These are having double stranded RNA and are spherical or polygonal in shape.



During latent mode of replication virus genome is not affected because it possess 5 hydromethyl cytosine (5–HMC) instead of cytosine. Viral genome modify bacterial nucleoid which produce modified enzymes, modified mRNAs and ribosomes that take part in replication and transcription of viral genome.



Economic importance of virus :





55

Connecting Concepts Viruses cause diseases like mumps, small pox, herpes, rabies, chicken pox, poliomyelitis,  Viroid genome is rod shaped circular hepatitis, Bird or Avian flu (H5NI), swine flu (HINI) and influenza. AIDS in humans is RNA which appears double stranded also caused by a virus. due to complementary base pairing

In plants, the symptoms can be mosaic formation, leaf rolling and curling, yellowing and interspersed by unpaired regions forming loops. It does not code for any vein clearing, dwarfing and stunted growth.

protein because of absence of initation codon. A viroid can multiply by two methods – DNA dependent and RNA T.O. Diener (1971) discovered some new infections agents, which are smaller than dependent.

VIROIDS 

viruses.   

 Prions are non-nucleic infectious entities which are formed by modification of a neuronal protein. Viroids contain only very low molecular weight RNA and protein coat. The can multiply by converting normal Viroids cause potato spindle tuber disease (PSTV), Chrysanthemum stunt, Citrus neuronal protein into prion form.

These sub-viral infections agents are called viroids.

exocortis, cucumber pale fruit etc.



Viroids cause persistent infections, i.e., never recovered.

LICHENS    

 On accumulation, prions cause degeneration of neuronal tissue, e.g., scrapie of sheep, mad cow disease, kuru, Cruetzfeldt-Jakob disease (CJD).

Lichens constitute a small and distinct group of plants having about 400 genera.

 Prions are resistant to proteases, In lichens, there are 2 components; i.e., algal partner called phycobiont and fungal partner nucleases, high temperature of autoclave, UV rays, formaldehyde called mycobiont. and other disinfectants except diethyl Lichens have distinct structure different from algal and fungal partner. pyrocarbonate. The diseases caused by Internal structure of lichen : The major portion of lichen body is formed of fungus. prions are, therefore, incurable.

Photosynthetic or algal symbiont constitutes hardly 5% of the body. 

There is an upper or outer cortex, algal zone, medulla, lower cortex and rhizines.



Rhizines are attaching devices made of fungal hyphae.

 Eating meats of animals suffering from a prion disease can cause a similar disease in humans .

56

BIOLOGY Connecting Concepts



 Soredia and Isidia are reproductive  propagules in lichen.   Cladonia rangifera (Reindeer Moss) is food for reindeer and other wild  animals of tundra, Cetraria islandica (Iceland Moss), Lecanora esculenta,  Endocarpon miniatum, Parmelia (Rock Flower), Umbilicaria esculenta are lichens eaten in different parts of the  world.  Orcein is a cytological stain (for  chromosomes) which is purified from Orchil. Litmus was at one time obtained  from Roccella montaingne.



 Incense in ‘dhup’ and ‘havan samagri’  is due to sweet scented lichens. Evernia and Ramalina extracts are added in  soaps and perfumes.  Lichens are sensitive to sulphur  dioxide pollution.

Only the algal zone contains photosynthetic partner. The rest of the zones are made of fungus only. In heteromerous lichens the alga is restricted to only algal zone e.g., Parmelia, Physica. In homoiomerous lichens the algal partner is distributed almost throughout the body, e.g., Collema. In 98% of the lichens, the mycobionts or fungal partners belong to ascomycetes. In the remaining the fungal partners belong to basidiomycetes and deuteromycetes. Depending upon the mycobiont partner, lichens are placed in three groups – ascolichens, basidiolichens and deuterolichens (lichenes imperfecti). Phycobionts either belong to cyanobacteria (e.g., Gleocapsa, Scytonema, Nostoc, Calothrix) or green algae (e.g., Coccomyxa, Trebouxia, Trentipohlia). Lichens show very slow growth. Lichens shows symbiotic relationships. They grow in varied habitats and can also grow in such habitats where other plants would not grow, e.g., on bare rock and in arctic region. Lichens reproduce vegetatively, sexually and asexually. Lichens are economically important as food and fodders, dyes, as a source of medicines etc.

BIOLOGICAL CLASSIFICATION

57

EXERCISE - 1 | NCERT BASED QUESTIONS 4.

Which option is true ?

Which of the following option is correct ? I. Mycoplasma has no cell wall. II. Mycoplasma is the smallest living organism. III. Mycoplasma cannot survive without O2. IV. Mycoplasma are pathogenic in animals and plants. V. True sexuality is not found in bacteria. VI. A sort of sexual reproduction occurs in bacterium by adopting a primitive DNA transfer from one bacterium to the other. (1) All (2) Only III (3) I, II, IV, V, VI (4) I, III, VI Which statement is true for dinoflagellates flagella ? (1) A single flagellum in the transverse groove between the cell plates. (2) A single flagellum in the longitudinal groove between the cell plates. (3) Two flagella one lies longitudinally and one transversely in a furrow between the wall plates. (4) No flagella.

em

D Collar Tail fibres Tail fibres Sheath

ad

C Sheath Head Collar Head

al

Identify A and B. Give the name of virus.

6.

Which is the correct option for the all given characteristics of fungi ? I. It includes unicellular as well as multicellular fungi. II. In multicellular forms hyphae are branched and septate. III. Conidiophore produces conidia (spores) exogenously in chain. IV. Sexual spores are ascopores produced endogenously in chain. V. Fruiting body is called ascocarp. (1) Phycomycetes (2) Sac fungi (3) Club fungi (4) Fungi imperfecti

7.

Which statement is incorrect about viruses ? (1) Viruses are obligate parasites. (2) Viruses can multiply only when they are inside the living cells. (3) Viruses cannot pass through bacterial filters. (4) Viruses are made up of protein and DNA or RNA (never both DNA and RNA).

8.

Which is the correct sequence of the sexual cycle of fungi ?

ic

2.

B Head Collar Sheath Tail fibres

ac

(1) (2) (3) (4)

A Tail fibres Sheath Head Collar

y.

bl

5.

og

sp

ot .c om

1.

ht tp

s: //

ne

et

m

ed

A

(1) (2) (3) (4)

3.

A RNA DNA RNA RNA

Type of virus - C

B B Capsid Capsid Lipid Protein

C Tobacco Mosaic Virus Tobacco Mosaic Virus Tobacco Mosaic Virus HIV

Column-I A. Phycomycetes I. B. Ascomycetes II. C. Basidiomycetes III. D. Deuteromycetes IV. The correct combination is – (1) A – II, B – I, C – IV, D – III (2) A – II, B – IV, C – I, D – III (3) A – IV, B – I, C – II, D – III (4) A – IV, B – III, C – II, D – I

Column-II Sac fungi Algal fungi Fungi imperfecti Club fungi

(1) Mitosis → Meiosis → Fertilization (2) Plasmogamy → Karyogamy → Meiosis (3) Meiosis → Plasmogamy → Karyogamy (4) Karyogamy → Plasmogamy → Meiosis

58 9.

BIOLOGY T. O. Diener discovered a new infectious agent that was smaller than viruses and having following characteristics.

(2) They include unicellular (e.g. yeast) and multicellular forms.

I.

It causes potato spindle tuber disease

(3) Their mycelium is coenocytic.

II.

It has free RNA

(4) Aspergillus, Claviceps, Neurospora are important members of Ascomycetes.

III. Molecular weight of RNA is low Which is the correct option for all the given characteristics ?

10.

(1) Viruses

(2) Viroids

(3) Virion

(4) Mycoplasma

14.

Choose the correct names of the different bacteria according to their shapes.

Which one of the following option is correct ?

(1) A – Cocci, B – Bacilli, C – Spirilla, D – Vibrio (2) A – Bacilli, B – Cocci, C – Spirilla, D – Vibrio (3) A – Spirilla, B – Bacilli, C – Cocci, D – Vibrio (4) A – Spirilla, B – Vibrio, C – Cocci, D – Bacilli 15.

Identify the following figures.

(1) A – Cell wall, B – Cell membrane, C – Heterocyst, D – DNA, E – Mucilagenous sheath (2) A – Cell wall, B – Cell membrane, C – DNA, D – Heterocyst, E – Mucilagenous sheath

(1) (2) (3) (4)

(3) A – Mucilagenous sheath, B – Cell membrane, C – DNA, D – Heterocyst, E – Cell wall (4) A – Cell membrane, B – Cell wall, C – DNA, D – Heterocyst, E – Mucilagenous sheath 11.

Which statement is not true about methanogens ?

16.

Kingdom monera comprises (1) plants of economic importance (2) all the plants studied in botany (3) prokaryotic organisms (4) plants of thallophyta group

17.

Whittaker is famous for (1) two kingdom classification (2) four kingdom classification (3) five kingdom classification (4) distinguishing bacteria and blue green algae

18.

In Whittaker’s five kingdom classification, eukaryotes were assigned to (1) all the five kingdom (2) only four of the five kingdoms (3) only three kingdom (4) only one kingdom

19.

Which group of plant have embryo but not vascular tissue? (1) Cyanophyta (2) Tracheophyta (3) Bryophyta (4) Chlorophyta

(1) They are archaebacteria. (2) They live in marshy areas. (3) Methane is their preferred carbon source. (4) They are present in guts of several ruminant animals (cow, buffaloes) and they produce biogas (CH4) from the dung of these animals. 12.

Choose the correct statements that correctly apply to kingdom Fungi. (1) Some fungi form beneficial interrelationships with plants (2) Certain fungi are natural sources of antibiotics (3) The fungal life cycle typically includes a spore stage (4) All

13.

Which one of the following option is not belong to Ascomycetes ? (1) They are saprophytic, decomposer, coprophilous (growing on dung) and parasitic.

A – Euglena, B – Paramoecium, C – Agaricus A – Euglena, B – Planaria, C – Agaricus A – Planaria, B – Paramoecium, C – Agaricus A – Euglena, B – Paramoecium, C – Aspergillus

BIOLOGICAL CLASSIFICATION 20.

Kingdom of unicellular eukaryotes is (1) Monera (2) Protista (3) Fungi (4) Plantae

21.

A true species consists of a population (1) sharing the same niche (2) interbreeding (3) feeding over the same food (4) reproductivity isolated

22.

Which one belongs to Monera? (1) Amoeba (2) Escherichia (3) Gelidium (4) Spirogyra

23.

Bacteria lack alternation of generation because there is (1) neither syngamy nor reduction division. (2) distinct chromosomes are absent. (3) no conjugation. (4) no exchange of genetic material.

24.

Protista includes (1) heterotrophs (2) chemoheterotrophs (3) chemoautotrophs (4) all the above

25.

Protistan genome has (1) membrane bound nucleoproteins embedded in cytoplasm. (2) free nucleic acid aggregates. (3) gene containing nucleoproteins condensed together in loose mass. (4) nucleoprotein in direct contact with cell substance.

59 26.

The main difference in Gram (+)ve and Gram (–)ve bacteria resides in their (1) cell wall (2) cell membrane (3) cytoplasm (4) flagella

27.

Organisms which are indicator of SO2 pollution of air (1) Mosses (2) Lichens (3) Mushrooms (4) Puffballs

28.

Decomposers are organisms that (1) secrete chemical substances, causing death of tissues. (2) operate in living body and disintegrate organic substances of cells step by step. (3) attack and kill plants as well as animals. (4) operate in relay terms, disintegrate step by step the organic constituents of dead body.

29.

The chemical compounds produced by the host plants to protect themselves against fungal infection is (1) phytotoxin (2) pathogen (3) phytoalexins (4) hormone

30.

Mycorrhiza is (1) a symbiotic association of plant roots and certain fungi. (2) an association of algae with fungi. (3) a fungus parasitie on root system of higher plants. (4) an association of Rhizobium with the roots of leguminous plants.

60

BIOLOGY

EXERCISE - 2 | Window to Competitive Exams

The organism used for alcoholic fermentation is [CBSE'95] (1) Pseudomonas (2) Penicillium (3) Aspergillus (4) Saccharomyces

5.

Which of the following is not correctly matched? [CBSE'95] (1) Root knot disease - Meloidogyne javanica (2) Smut of bajra - Tolysporium penicillariae (3) Covered smut of barley - Ustilago nuda (4) Late blight of potato - Phytophthora infestans White rust disease is caused by [CBSE'95] (1) Claviceps (2) Alternaria (3) Phytophthora (4) Albugo candida

7.

Bacteria were regarded to be plants because (1) some of them are green (2) they are present every where (3) some of them cannot move (4) they have a rigid cell wall.

Which one of the following is not true about lichens? [CBSE'96] (1) Their body is composed of both algal and fungal cells. (2) Some species form food for reindeers in arctic regions. (3) Some species can be used as pollution indicators. (4) They grow very fast at the rate of about 2 cm per year.

15.

Antibiotics are mostly obtained from (1) bacteria (2) viruses (3) angiosperms (4) fungi

ca d

la

ic a

ed

In dinophyceae the two flagella are (1) anterior (2) one transverse and other vertical (3) lateral (4) posterior

ee

10.

Azotobacter and Bacillus polymyxa are the examples of [CBSE'96] (1) symbiotic nitrogen-fixers (2) non-symbiotic nitrogen-fixers (3) ammonifying bacteria (4) disease-causing bacteria

ht tp

s:

//n

An edible fungus is (1) Aspergillus (3) Polyporus

(2) (4)

Ustilago Morchella

[CBSE'96]

In bacteria the site for respiratory activity is found in [CBSE'97] (1) episome (2) microsome (3) ribosome (4) cell membrane/mesosome

17.

Which one of the following sets includes the bacterial diseases ? [AIIMS'97] (1) Cholera, typhoid, mumps (2) Tetanus, tuberculosis, measles (3) Malaria, mumps, poliomyelitis (4) Diptheria, leprosy, plague

18.

In protists the locomotory organelles are [AMU'97] (1) flagella (2) flagella, cilia and pseudopodia (3) flagella and cilia (4) flagella, cilia, pseudopodia and wrigglers.

19.

Plasmogamy is fusion of [AIIMS'97] (1) two haploid cells including their nuclei. (2) two haploid cells without nuclear fusion. (3) sperm and egg. (4) sperm and two polar nuclei.

[CBSE'95]

9.

[CBSE'96]

16.

[PMT'95]

tm

8.

14.

em

6.

Influenza virus has (1) DNA (2) RNA (3) both DNA and RNA (4) only proteins and no nucleic acids

om

4.

13.

.c

Which of the following organism possesses characteristics of both plants and animals? [CBSE'95] (1) Bacteria (2) Euglena (3) Mycoplasma (4) Paramoecium

In bacterial chromosomes, the nucleic acid are [CBSE'96] (1) linear DNA molecule (2) circular DNA molecule (3) of two types DNA and RNA (4) linear RNA molecule

ot

3.

12.

sp

In some viruses, RNA is present instead of DNA indicating that [CBSE'95] (1) their nucleic acid must combine with host DNA before replication (2) they cannot replicate (3) there is no hereditary information (4) RNA can transfer heredity material

Sex factor in bacteria is [CBSE'96] (1) chromosomal replicon (2) F-replicon (3) RNA (4) sex-pilus

og

2.

11.

bl

Which of the following cannot be grown on artificial culture medium ? [CBSE'94] (1) Escherichia coli (2) TMV (3) Aspergillus (4) Yeast

y.

1.

[MP'95]

BIOLOGICAL CLASSIFICATION 20.

21.

22.

23.

24.

61

Which one of the following statements about viruses is correct? [CBSE'97] (1) Viruses possess their own metabolic system. (2) Viruses contain either DNA or RNA. (3) Viruses are facultative parasites. (4) Viruses are readily killed by antibiotics. Two bacteria found to be very useful in genetic engineering experiments are [CBSE'98] (1) Escherichia and Agrobacterium (2) Nitrobacter and Azotobacter (3) Rhizobium and Diplococcus (4) Nitrosomonas and Klebsiella The main role of bacteria in the carbon cycle is (1) photosynthesis [CBSE'98] (2) chemosynthesis (3) digestion or breakdown of organic compounds (4) assimilation of nitrogenous compounds A few organisms are known to grow and multiply at temperatures of 100–105ºC. They belong to [CBSE'98] (1) marine archaebacteria (2) thermophilic sulphur bacteria (3) blue-green algae (cyanobacteria) (4) thermophilic, subaerial fungi Which one of the following micro-organisms is used for production of citric acid in industries? [CBSE'98] (1) Penicillium citrinum (2) Aspergillus niger (3) Rhizopus nigricans (4) Lactobacillus bulgaris

25.

Transfer of genetic material from one bacterium to another in the transduction process is through [CBSE'98] (1) conjugation (2) bacteriophages (3) another bacterium (4) physical contact between donor and recipient strain

26.

Yeast Saccharomyces cerevisiae is used in the industrial production of [CBSE'98] (1) citric acid (2) tetracyclin (3) ethanol (4) butanol

27.

In prokaryotes, the genetic material is (1) linear DNA with histones (2) circular DNA with histones (3) linear DNA without histones (4) circular DNA without histones

[CBSE'99]

28.

Photosynthetic bacteria have pigments in [CBSE'99] (1) leucoplasts (2) chloroplasts (3) chromoplasts (4) chromatophores

29.

Which organism is used for increasing the yield of rice ? [CBSE'99] (1) Anabaena (2) Bacillus popilliae (3) Sesbania (4) Bacillus polymyxa

30.

Interferons are (1) antiviral proteins (3) anticancer proteins

[CBSE'99] (2) antibacterial proteins (4) complex proteins

31.

In fungi stored food material is [CBSE'2000] (1) glycogen (2) starch (3) sucrose (4) glucose

32.

A virus can be considered a living organism because it (1) responds to touch stimulus [CBSE'2000] (2) respires (3) reproduces (inside the host) (4) can cause disease

33.

‘Comma’ shaped bacteria are known as (1) coccus (2) spiral (3) lophotrichus (4) vibrio

34.

Which bacteria is utilized in gober gas plant? [CBSE'02] (1) Methanogens (2) Nitrifying bacteria (3) Ammonifying bacteria (4) Denitrifying bacteria

35.

In Amoeba and Paramoecium osmoregulation occurs through [CBSE'02] (1) pseudopodia (2) nucleus (3) contractile vacuole (4) general surface

36.

Virus attacks a bacterium but neither multiplies nor the bacterium dies due to [AMU'02] (1) lysogeny (2) adsorption (3) assimilation (4) viral stability

37.

Mycorrhiza represents (1) antagonism (3) symbiosis

38.

Which of the following statements is not true for retroviruses? [CBSE'04] (1) DNA is not present at any stage in the life cycle of retroviruses. (2) Retroviruses carry gene for RNA-dependent DNA polymerase. (3) The genetic material in mature retroviruses is RNA. (4) Retroviruses are causative agents for certain kinds of cancer in men.

39.

Litmus is naturally extracted from [Orissa'04] (1) algae (2) fungi (3) lichens (4) protozoans

40.

Which of the following statements regarding cilia is not correct ? [CBSE'06] (1) Cilia are hair-like cellular appendages. (2) Microtubules of cilia are composed of tubulin. (3) Cilia contain an outer ring of nine doublet microtubules surrounding two single microtubules in center. (4) The organized beating of cilia is controlled by fluxes of Ca2+ across the membrane.

41.

Smallest virus is [CBSE'06] (1) Foot and Mouth virus (2) Alfalfa Mosaic virus (3) Pseudomonas Pf (4) TMV

42.

Host component of viral envelope is mostly [CBSE'06] (1) lipids (2) carbohydrates (3) lipids and proteins (4) lipids and carbohydrates

(2) endemism (4) parasitism

[AFMC'01]

[CBSE'03]

62

BIOLOGY

43.

Capsid is (1) genetic material of virus (2 protein cover of virus (3) extra genetic material of bacterium (4) house keeping genome of bacterium

44.

Which pair of the following belongs to Basidiomycetes (1) Puffballs and Claviceps [CBSE'07] (2) Peziza and Alternaria (3) Morchella and mushrooms (4) Birds nest fungi and puffballs

45.

The thalloid body of a slime mould (Myxomycetes) is known as [CBSE'08] (1) plasmodium (2) fruiting body (3) mycelium (4) protonema

46.

Flagella of prokaryotic and eukaryotic cells differ in [AFMC'08] (1) type of movement and placement in cell (2) location in cell and mode of functioning (3) micro-tubular organization and type of movement (4) micro-tubular organization and function

47.

[CBSE'06]

Which one of the following statements is true about Archaea? [CBSE'08] (1) Archaea resemble eukaryotes in all respects. (2) Archaea have some novel features that are absent in other prokaryotes and eukaryotes. (3) Archaea completely differ from both prokaryotes and eukaryotes. (4) Archaea completely differ from prokaryotes.

48.

Mannitol is the stored food in (1) Porphyra (2) Fucus (3) Gracillaria (4) Chara

49.

Which of the following fixes atmospheric N2?[AFMC'09] (1) Nostoc (2) Algae (3) Methanogens (4) None of these

50.

51.

52.

[CBSE'09]

Which one is the wrong pairing for the disease and its causal organism? [CBSE PMT 2009] (1) Black rust of wheat - Puccinia graminis (2) Loose smut of wheat - Ustilago nuda (3) Root-knot of vegetables - Meloidogyne sp (4) Late blight of potato - Alternaria solani Phylogenetic system of classification is based on: [CBSE PMT 2009] (1) morphological features (2) chemical constituents (3) floral characters (4) evolutionary relationships Mannitol is the stored food in: [CBSE PMT 2009] (1) Porphyra (2) Fucus (3) Gracillaria (4) Chara

53.

Match the items in column I with those in column II and choose the correct option [Kerala PMT 2009]

(1) (2) (3) (4) (5)

A – 2, B – 3, C – 4, D – 5 E – 1 A – 1, B – 2, C – 3, D – 5 E – 4 A – 2, B – 5, C – 3, D – 1 E – 4 A – 1, B – 2, C – 3, D – 4 E – 5 A – 2, B – 3, C – 4, D – 1 E – 5

54.

The by (1) (2) (3) (4) (5)

phylogenetic system of classification was put forth [Kerala PMT 2009] Carolus Linnaeus George Bentham and Joseph Dalton Hooker Aristotle Theophrastus Adolf Engler and Karl Prantl

55.

Slimy mass of protoplasm with many nuclei and an Amoeba-like thalloid body is a characteristic feature of [Kerala PMT 2009] (1) ascomycetes (2) actinomycetes (3) phycomycetes (4) basidiomycetes (5) myxomycetes

56.

Single-celled eukaryotes are included in [CBSE PMT 2010] (1) Protista (2) Fungi (3) Archaea (4) Monera

57.

Ringworm in humans is caused by : [CBSE PMT 2010] (1) Bacteria (2) Fungi (3) Nematodes (4) Viruses

58.

Membrane-bound organelles are absent in: [CBSE PMT 2010] (1) Saccharomyces (2) Streptococcus (3) Chlamydomonas (4) Plasmodium

59.

Virus envelope is known as: [CBSE PMT 2010] (1) Capsid (2) Virion (3) Nucleoprotein (4) Core

60.

Which of the following is not a character of protista? [Kerala PMT 2010] (1) Protists are prokaryotic (2) Some protists have cell walls. (3) Mode of nutrition is both autotrophic and heterotrophic (4) Body organization is cellular (5) Membrane bound organelles are present in cells

BIOLOGICAL CLASSIFICATION 61.

62.

Specialized cells called heterocysts are present in [Kerala PMT 2010] (1) dinoflagellates (2) chrysophytes (3) euglenoids (4) cyanobacteria (5) archaebacteria Which of the following is a flagellated protozoan? [Kerala PMT 2010] (1) Amoeba (2) Entamoeba (3) Plasmodium (4) Trypanosoma (5) Paramoecium

63.

Systema Naturae was written by [Kerala PMT 2010] (1) Ernst Mayr (2) Carolus Linnaeus (3) R. H. Whittaker (4) W. M. Stanley (5) M. W. Beijernick

64.

Match column I with column II and choose the right option [Kerala PMT 2010]

(1) (2) (3) (4) (5)

A – 4, B – 3, C – 1, D – 2 A – 2, B – 3, C – 4, D – 1 A – 4, B – 1, C – 2, D – 3 A – 3, B – 4, C – 2, D – 1 A – 2, B – 1, C – 4, D – 3

65.

Which one of the following is not a biofertilizer? [CBSE PMT 2011] (1) Agrobacterium (2) Rhizobium (3) Nostoc (4) Mycorrhiza

66.

Ethanol is commercially produced through a particular species of : [CBSE PMT 2011] (1) Saccharomyces (2) Clostridium (3) Trichoderma (4) Aspergillus

67.

Which one of the following organisms is not an example of eukaryotic cells? [CBSE PMT 2011] (1) Paramecium caudatum(2) Escherichia coli (3) Euglena viridis (4) Amoeba proteus

68.

Archegoniophore is present in : [CBSE PMT 2011] (1) Marchantia (2) Chara (3) Adiantum (4) Funaria

69.

In eubacteria, a cellular component that resembles eukaryotic cells is : [CBSE PMT 2011] (1) plasma membrane (2) nucleus (3) ribosomes (4) cell wall

70.

Compared with the gametophytes of the bryophytes the gametophytes of vascular plant are [CBSE PMT 2011] (1) smaller but have larger sex organs (2) larger but have smaller sex organs (3) larger and have larger sex organs (4) smaller and have smaller sex organs

63 71.

The gametophyte is not an independent, free living generation in : [CBSE PMT 2011] (1) Polytrichum (2) Adiantum (3) Marchantia (4) Pinus

72.

Organisms called methanogens are most abundant in a : [CBSE PMT 2011] (1) sulphur rock (2) cattle yard (3) polluted stream (4) hot spring

73.

Which one of the following pairs is wrongly matched while the remaining three are correct? [CBSE PMT 2011M] (1) Penicillium - Conidia (2) Water hyacinth - Runner (3) Bryophyllum - Leaf buds (4) Agave - Bulbils

74.

Consider the following four statements whether they are correct or wrong? [CBSE PMT 2011M] (1) The sporophyte in liverworts is more elaborate than that in mosses (2) Salvinia is heterosporous (3) The life cycle in all seed-bearing plants is diplontic (4) In Pinus male and female cones are borne on different trees (1) Statements (1) and (3) (2) Statements (1) and (4) (3) Statements (2) and (3) (4) Statements (1) and (2)

75.

Selaginella and Salvinia are considered to represent a significant step toward evolution of seed habit because: [CBSE PMT 2011M] (1) female gametophyte is free and gets dispersed like seeds (2) female gametophyte lacks archaegonia (3) megaspores possess endosperm and embryo surrounded by seed coat (4) embryo develops in female gametophyte which is retained on parent sporophyte.

76.

Examine the figure given below and zvselect the right option giving all the four parts (a, b, c and d) correctly identified. [CBSE PMT 2011M]

(1) (A) (C) (2) (A) (C) (3) (A) (C) (4) (A) (C)

Archegoniophore Gemmacup Archegoniophore Bud Seta Protonema Antheridiophore Globule

(B) (D) (B) (D) (B) (D) (B) (D)

Female thallus Rhizoids Female thallus Foot Sporophyte Rhizoids Male thallus Roots

64

BIOLOGY

77.

In which of the following will you look for E. coli [AFMC 2011] (1) milk (2) water (3) human intestine (4) soil

78.

Early and late blight of potato are caused respectively by [AFMC 2011] (1) Fusarium and Claviceps (2) Gibberella and Penicillium (3) Aspergillus and Ustilago (4) None of the above

79.

Powdery mildew of wheat is caused by a species of [JIPMER-2011] (1) Puccinia (2) Erysiphe (3) Ustilago (4) Albugo

80.

Nucleic acid is absent in (1) virus (3) prion

[JIPMER-2011] (2) viroid (4) mycoplasma

81.

In most fungi, cell wall is chiefly made of [JIPMER-2011] (1) cellulose (2) chitin (3) protein (4) lipid

82.

In prokaryotes, chromatophores are [JIPMER-2011] (1) specialised granules responsible for colouration of cells (2) structures responsible for organising the shape of the organism (3) inclusion bodies lying free inside the cells for carrying out various metabolic activities (4) internal membrane systems that may become extensive and complex in photosynthetic bacteria

83.

Viruses that infect bacterial multiplication and cause their lysis, are called [JIPMER-2011] (1) lysozymes (2) lipolytic (3) lytic (4) lysogenic

84.

Match the following and select the correct combination from the options given below. [Kerala PMT 2011]

86.

Which of the following is not matched correctly? [Kerala PMT 2011] (1) Anabaena Cyanobacteria (2) Amoeba Protozoa (3) Gonyaulax Dinoflagellates (4) Thermoacidophils Archaebacteria (5) Albugo Chrysophytes

87.

Which one of the following is a characteristic feature of Chrysophytes? [Kerala PMT 2011] (1) They are parasitic forms which cause diseases in animals (2) They have a protein rich layer called pellicle (3) They have indestructible wall layer deposited with silica (4) They are commonly called dinoflagellates (5) They are saprophytic protista.

88.

Which of the following does not belong to the kingdom Protista? [Kerala PMT 2011] (1) Chrysophytes (2) Euglenoids (3) Ascomycetes (4) Dinoflagellates (5) Protozoans

89.

Find out the correct statement. [Kerala PMT 2011] (1) in lichens, the algal component is called phycobiont and fungal component is known as mycobiont, which are heterotrophic and autotrophic respectively. (2) viroid contains RNA of low molecular weight and protein coat. (3) a virus contains both RNA and DNA. (4) viruses are obligatory parasites. (5) viruses that infect plants have double stranded RNA.

90.

Match column I with column II and select the correct option. [Kerala PMT 2011]

(1) (2) (3) (4) (5) (1) (2) (3) (4) (5) 85.

A – 4, B – 3, C – 2, D – 1 A – 1, B – 2, C – 3, D – 4 A – 3, B – 4, C – 2, D – 1 A – 4, B – 2, C – 3, D – 1 A – 2, B – 3, C – 4, D – 1

Which of the following is a unicellular sac-fungus? [Kerala PMT 2011] (1) Claviceps (2) Saccharomyces (3) Penicillium (4) Neurospora (5) Aspergillus

A – 3, B – 4, C – 1, D – 2 A – 2, B – 3, C – 4, D – 1 A – 4, B – 1, C – 2, D – 3 A – 3, B – 4, C – 2, D – 1 A – 2, B – 1, C – 4, D – 3

91.

The most abundant prokaryotes helpful to humans in making curd from milk and in production of antibiotics are the ones categorised as : [CBSE 2012] (1) Cyanobacteria (2) Archaebacteria (3) Chemosynthetic autotrophs (4) Heterotrophic bacteria

92.

The cyanobacteria are also referred to as [CBSE 2012] (1) Protists (2) Golden algae (3) Slime moulds (4) Blue green algae

BIOLOGICAL CLASSIFICATION 93.

94.

Which statement is wrong for viruses? [CBSE 2012] (1) All are parasites. (2) All of them have helical symmetry. (3) They have ability to synthesize nucleic acids and proteins. (4) Antibiotics have no effect on them.

Which one single organism or the pair of organisms is correctly assigned to its taxonomic group? [CBSE 2012] (1) Paramoecium and Plasmodium belong to the same kingdom as that of Penicillium. (2) Lichen is a composite organism formed from the symbiotic association of an algae and a protozoan. (3) Yeast used in making bread and beer is a fungus. (4) Nostoc and Anabaena are examples of protista. 95. The most abundant prokaryotes helpful to humans in making curd from milk and in production of antibiotics are the ones categorised as : [CBSE PMT 2012] (1) Cyanobacteria (2) Archaebacteria (3) Chemosynthetic autotrophs (4) Heterotrophic bacteria 96. The cyanobacteria are also referred to as [CBSE PMT 2012] (1) protists (2) golden algae (3) Slime moulds (4) blue green algae 97. Which statement is wrong for viruses [CBSE PMT 2012] (1) All are parasites (2) All of them have helical symmetry (3) They have ability to synthesize nucleic acids and proteins (4) Antibiotics have no effect on them 98. Which one single organism or the pair of organisms is correctly assigned to its taxonomic group [CBSE PMT 2012] (1) Paramoecium and Plasmodium belong to the same kingdom as that of Penicillium (2) Lichen is a composite organism formed from the symbiotic association of an algae and a protozoan (3) Yeast used in making bread and beer is a fungus (4) Nostoc and Anabaena are examples of protista 99. How many organisms in the list given below are autotrophs? Lactobacillus, Nostoc, Chara, Nitrosomonas, Nitrobacter, Streptomyces, Saccharomyces, Trypanosomes, Porphyra, Wolffia [CBSE PMT 2012M] (1) Four (2) Five (3) Six (4) Three 100. In the five-kingdom classification, Chlamydomonas and Chlorella have been included in [CBSE PMT 2012M] (1) protista (2) algae (3) plantae (4) monera

65 101. Which one of the following sets of items in the options 1 - 4 are correctly categorized with one exception in it? [CBSE PMT 2012M] Items Category xception (1) UAA, UAG, UGA Stop codons UAG (2) Kangaroo, Australian Wombat Koala, Wombat marsupials (3) Plasmodium, Protozoan Cuscuta Cuscuta, parasites Trypanosoma (4) Typhoid, Bacterial Diphtheria Pneumonia, diseases Diphtheria 102. The classification of Linnaeus was mainly based on [AIIMS 2012] (1) Sepals (2) Carpels (3) Petals (4) Stamens 103. Phylum protozoa is classified on the basis of (1) mode of reproduction [AFMC 2012] (2) locomotory organelles (3) mode of nutrition (4) none of these. 104. Which of the following fixes atmospheric N2? [AFMC 2012] (1) Nostoc (2) Algae (3) Methanogens (4) None of these 105. Movements by pseudopodia of Amoeba are due to change in [JIPMER-2012] (1) pressure (2) atmosphere (3) temperature (4) viscosity 106. In Whittaker’s system of classification, prokaryotes belong to the kingdom [JIPMER-2012] (1) Monera (2) Protista (3) Animalia (4) Fungi 107. Water bloom is generally caused by [JIPMER-2012] (1) green algae (2) blue green algae (3) bacteria (4) Hydrilla 108. Covered smut of barley is caused by [JIPMER-2012] (1) Ustilago hordei (2) Tilletia caries (3) Ustilago nuda (4) Colletotrichum falcatum 109. Which one of the following is a saprophytic protist? [Kerala PMT 2012] (1) Desmid (2) Slime mould (3) Euglena (4) Gonyaulax (5) Nostoc 110. Which one of the following is a flagellated protozoan? [Kerala PMT 2012] (1) Trypanosoma (2) Plasmodium (3) Amoeba (4) Paramoecium (5) Entamoeba

66

BIOLOGY

111. Consider the following statements with respect to characteristic features of the kingdom. [Kerala PMT 2012] A. In animalia the mode of nutrition is autotrophic. B. In monera the nuclear membrane is present. C. In protista the cell type is prokaryotic. D. In plantae the cell wall is present. Of the above statements (1) A alone is correct (2) B alone is correct (3) C alone is correct (4) D alone is correct (5) A, B and C are correct 112. Match the following and choose the correct combination from the options given. [Kerala PMT 2012] Column I Column II (Group) (Example) A. Eubacteria 1. Trichoderma B. Dinoflagellates 2. Albugo C. Phycomycetes 3. Gonyaulax D. Deuteromycetes 4. Anabaena (1) A – 1; B – 2; C – 3; D – 4 (2) A – 2; B – 3; C – 4; D – 1 (3) A – 4; B – 3; C – 2; D – 1 (4) A – 3; B – 4; C – 1; D – 2 (5) A – 4; B – 3; C – 1; D – 2 113. Which of the following are the characters of dinoflagellates? [Kerala PMT 2012] A. Planktonic golden yellow algae with soap box like structure. B. Marine red biflagellated protista. C. Appear yellow, green, brown, blue and red in colour. D. Biflagellated organisms with pellicle. E. Saprophytic (or) parasitic unicellular forms. (1) A, B and C only (2) B, D and E only (3) B and C only (4) B and E only (5) C, D and E only 114. Match column I with Column II and choose the correct option. [Kerala PMT 2013] Column I Column II (A) Ernst Mayr 1. Discovered viroids (B) Whittaker 2. Gave the name virus (C) Pasteur 3. Proposed Five Kingdom classification (D) Diener 4. Darwin of the 20th century (1) A-4, B-3, C-2, D-1 (2) A-3, B-4, C-2, D-1 (3) A-2, B-3, C-4, D-1 (4) A-1, B-2, C-3, D-4 (5) A-4, B-3, C-1, D-2 115. I.

Unicellular, colonial, filamentous, marine or terrestrial forms [Kerala PMT 2013] II. The colonies are surrounded by a gelatinous sheath III. Some can fix atmospheric nitrogen in specialised cells called heterocysts IV. They often form blooms in water bodies

These above characters are seen in (1) Archaebacteria (2) Cyanobacteria (3) Chrysophytes (4) Dinoflagellates (5) Slime moulds 116. Pick out the wrong statement [Kerala PMT 2013] (1) Lichens are symbiotic associations. (2) Lichens are very good pollution indicators. (3) Lichens do not grow in unpolluted areas. (4) The algal component of lichen is known as phycobiont. (5) The fungal component of lichen is known as mycobiont. 117. Match the following and choose the correct combination from the options given. [Kerala PMT 2013] (Column I Column II (Fungus Name) (Commonly called) (A) Puccinia 1. Yeast (B) Ustilago 2. Mushroom (C) Agaricus 3. Smut fungus (D) Saccharomyces 4. Rust fungus (1) A-1, B-2, C-3, D-4 (2) A-2, B-3, C-4, D-1 (3) A-3, B-4, C-1, D-2 (4) A-4, B-3, C-2, D-1 (5) A-4, B-3, C-1, D-2 118. Which of the following are likely to be present in deep sea water ? [AIPMT (NEET) 2013] (1) Eubacteria (2) Blue-green algae (3) Saprophytic fungi (4) Archaebacteria 119. Which of the following are likely to be present in deep sea water ? [AIPMT (NEET) 2013] (1) Eubacteria (2) Blue-green algae (3) Saprophytic fungi (4) Archaebacteria 120. Choose the correct names of the different bacteria according to their shapes. [AIIMS 2013]

(1) (2) (3) (4)

A – Cocci, B – Bacilli, C – Spirilla, D – Vibrio A – Bacilli, B – Cocci, C – Spirilla, D – Vibrio A – Spirilla, B – Bacilli, C – Cocci, D – Vibrio A – Spirilla, B – Vibrio, C – Cocci, D – Bacilli

121. Which pair of the following belongs to Basidiomycetes? [AIIMS 2013] (1) Puffballs and Claviceps (2) Peziza and Alternaria (3) Morchella and mushrooms (4) Birds nest fungi and puffballs

BIOLOGICAL CLASSIFICATION

67

122. Which one of the following is true for fungi? (1) They are phagotrophs [NEET Kar. 2013] (2) They lack a rigid cell wall (3) They are heterotrophs (4) They lack nuclear membrane 123. Specialized cells for fixing atmospheric nitrogen in Nostoc are [NEET Kar. 2013] (1) Akinetes (2) Heterocysts (3) Hormogonia (4) Nodules 124. Satellite RNAs are present in some [NEET Kar. 2013] (1) Plant viruses (2) Viroids (3) Prions (4) Bacteriophages 125. Five kingdom system of classification suggested by R.H. Whittaker is not based on: [AIPMT - 2014] (1) Presence or absence of a well defined nucleus. (2) Mode of reproduction. (3) Mode of nutrition. (4) Complexity of body organisation. 126. Which one of the following fungi contains hallucinogens? [AIPMT - 2014] (1) Morchella esculenta (2) Amanita muscaria (3) Neurospora sp. (4) Ustilago sp. 127. Archaebacteria differ from eubacteria in:[AIPMT - 2014] (1) Cell membrane (2) Mode of nutrition (3) Cell shape (4) Mode of reproduction 128. Which of the following shows coiled RNA strand and capsomeres? [AIPMT - 2014] (1) Polio virus (2) Tobacco masaic virus (3) Measles virus (4) Retrovirus

132. True nucleus is absent in : [AIPMT 2015] (1) Mucor (2) Vaucheria (3) Volvox (4) Anabaena 133. Which of the following structures is not found in a prokaryotic cell? [RE-TEST AIPMT 2015] (1) Ribosome (2) Mesosome (3) Plasma membrane (4) Nuclear envelope 134. The imperfect fungi which are decomposer of litter and help in mineral cycling belong to: [RE-TEST AIPMT 2015] (1) Basidiomycetes (2) Phycomycetes (3) Ascomycetes (4) Deuteromycetes 135. The structures that help some bacteria to attach to rocks and / or host tissues are: [RE-TEST AIPMT 2015] (1) Fimbriae (2) Mesosomes (3) Holdfast (4) Rhizoids 136. Morels and Buffles groups of fungi are classified [AMU’s 2015] (1) Phycomycetes (2) Deuteromycetes (3) Basidiomycetes (4) Ascomycetes 137. Which of the following are likely to be present in deep sea water? [UP CPMT 2015] (1) Eubacteria (2) Blue-green algae (3) Saprophytic fungi (4) Archaebacteria

[AIPMT - 2014]

138. Which of the following is not correctly matched for the organism and its cell wall degrading cnzyme? [UP CPMT 2015] (1) Plant cells – Cellulase (2) Algal – Methylase (3) Fungi – Chitinase (4) Bacteria – Lysozyme

130. The motile bacteria are able to move by: [AIPMT 2014] (1) Fimbriae (2) Flagella (3) Cilia (4) Pili

139. The proteins that reproduce within the living cells are termed as [UP CPMT 2015] (1) Plasmids (2) Phages (3) Prions (4) Prophages

129. Viruses have: (1) DNA enclosed in a protein coat (2) Prokaryotic nucleus (3) Single chromosome (4) Both DNA and RNA

131. Which one one of the following matches is correct ? [AIPMT 2015]

140. In which of the following are heterocysts seen? [UP CPMT 2015] (1) Chara (2) Polysiphonia (3) Spirogyra (4) Nostoc 141. Fungi without sexual or perfect stages are classified as [UP CPMT 2015] (1) Phycomycetes (2) Deuteromyectes (3) Dermatomycetes (4) Ascomycetes

68

BIOLOGY

EXERCISE - 3 | Test Yourself

Plant classification proposed by Carolus Linnaeus was artificial because it was based on (1) only a few morphological characters (2) evolutionary tendencies which are diverse (3) anatomical characters which are adaptive in nature (4) physiological traits alongwith morphological characters Two morphologically similar populations are intersterile. They belong to (1) one species (2) two biospecies (3) two sibling species (4) none of the above

6.

In the five kingdom system of classification, which single kingdom out of the following can include bluegreen algae, nitrogen fixing bacteria and methanogenic archaebacteria ? (1) Monera (2) Fungi (3) Plantae (4) Protista

7.

Species are considered as (1) real units of classification devised by taxonomists (2) real basic units of classification (3) the lowest units of classification (4) artificial concept of human mind which cannot be defined in absolute terms

Which of the following statement is correct ? (1) E.coli is gram –ve bacterium while Rhizobium japoncium is gram +ve bacterium. (2) Both E.coli and Rhizobium japonicum are gram –ve. (3) Both E.coli and Rhizobium japonicum are gram +ve. (4) E.coli is gram +ve, Rhizobium japonicum is gram –ve.

12.

Choose the right combination Column-I Column-II A. Escherichia coli I. Nif gene B. Rhizobium melilotae II. Digestive hydrocarbon of crude oil C. Bacillus thuringiensis III. Production of human insulin D. Pseudomonas putida IV. Biological control of fungal disease V. Bio-decomposed insectiside (1) A – III, B – I, C – V, D – IV (2) A – I, B – II, C – III, D – IV (3) A – II, B – I, C – III, D – IV (4) A – III, B – I, C – V, D – II

In five kingdom classification land plants are classified under (1) bryophyta, pteridophyta and spermatophytes (2) bryophyta and trachaeophyta (3) embryophyta and spermatophyta (4) bryophyta and archaegoniatae

13.

In Bacillus subtilis, long filamentous chains embedded in a mass of mucilage forming a scum layer on substratum. It is called as (1) palmella stage (2) torula stage (3) zoogloea stage (4) none of the above

14.

Penicillin inhibits bacterial multiplication because (1) it checks spindle formation (2) it destroys chromosome formation (3) it inhibits cell wall formation (4) it checks RNA synthesis

15.

Anaerobic decomposition is called (1) putrefaction (2) nitrification (3) denitrification (4) N2 fixation

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5.

11.

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4.

Natural system of classification differs from artificial system in (1) employing only one floral trait (2) taking only one vegetative trait (3) bringing out similarities and dissimilarities (4) developing evolutionary trends

Which option is correct for structure of cell wall of fungi and bacteria ? (1) Both have glycopeptide. (2) Both are made up of N-acetylglucosamine. (3) Both are made up of N-acetylglucosamine and cellulose. (4) Both are made up of chitin.

Bacteria are found to be primitive organisms because they (1) are small, microscopic which are not seen with naked eye

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9.

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3.

10.

ot

Two plants are taxonomically related if (1) they store carbohydrate in the same type of molecule (2) both obtain energy from hydrolysis of ATP into ADP and inorganic phosphate (3) both have similarly lobed palmate leaves (4) both have pinnately veined leaves

sp

2.

(2) cause serious diseases to human being, domesticated animals and crop plants (3) produce endospores which are very resistant to adverse conditions (4) possess incipient nucleus and show amitotic division

og

Classical systematics embodies (1) biological concept (2) species concept (3) typological concept (4) all the above

bl

1.

BIOLOGICAL CLASSIFICATION 16.

Which of the following statement is not true about Frankia ? (1) It can induce root nodules on many plant species. (2) It cannot fix nitrogen in the free-living state. (3) It cannot fix specialized vesicles in which the nitrogenase is protected from oxygen by a chemical barrier involving triterpene hapanoids. (4) Like Rhizobium, it usually infects its host plant through root hair deformation and stimulates cell proliferation in the host’s cortex.

17.

Mycoplasma is a (1) eukaryotic and multicellular (2) prokaryotic and multicellular (3) prokaryotic and unicellular (4) eukaryotic and unicellular

18.

Mycoplasma is pleuromorphic due to (1) absence of cell wall (2) presence of three layered cell membrane (3) the presence of sterol (4) none of these

19.

Which statement is correct for both blue-green algae and bacteria ? (1) Both show anaerobic respiration. (2) Both have chlorophyll. (3) Both are devoid of true nucleus. (4) None of the above

20.

Why bacteria do not survive in the pickle which has high salt contents ? (1) Salt retards the rate of reproduction of bacteria. (2) Bacteria do not get sunlight for photosynthesis. (3) Due to plasmolysis, bacteria die. (4) Essential elements for bacterial viability are not present in the pickle.

69 (1) Both X and Y are marine species (2) Species Y is marine species and X is fresh water species (3) Species X is marine species and Y is fresh water species (4) Both X and Y are fresh water species 26.

Which of the following combinations of characters is true for slime moulds ? (1) Parasitic, plasmodium with true walls, spores dispersed by air currents. (2) Saprophytic, plasmodium without walls, spores dispersed by water. (3) Parasitic, plasmodium without walls, spores dispersed by water. (4) Saprophytic, plasmodium without walls, spores dispersed by air currents.

27.

Match the following

A. B. C. D. (1) (2) (3) (4)

Column-I (Group) Bacillariophyceae Dinoflagellates Euglenoids Protozoans A B C I III II I IV III IV II III IV III II

Column-II (Example) I. Paramoecium II. Euglena III. Gonyaulax IV. Diatoms D IV II I I

28.

What is common about Trypanosoma, Noctiluca, Monocystis and Giardia ? (1) These are all unicellular protists. (2) They have flagella. (3) They produce spores. (4) These are all parasites.

21.

Contagium vivum fluidum was proposed by (1) D. J. Ivanowsky (2) M.W. Beijerinek (3) Stanley (4) Robert Hook

22.

Select the incorrect pair. (1) Porifera – choanocytes (2) Coelenterata – prokaryote (3) Annelida – segmentation (4) Monera – eukaryote

29.

A group of fungi with septate mycelium in which sexual reproduction is either unknown or lacking are classified under (1) phycomycetes (2) deuteromycetes (3) ascomycetes (4) basidiomycetes

23.

Which organism behaves like plants in the presence of sunlight and absence of organic food, but in reverse conditions behaves like animal ? (1) Archaebacteria (2) Euglena (3) Nostoc (4) Paramoecium

30.

24.

In Paramoecium, both autogamy and conjugation are sexual processes because of (1) gene recombination (2) involvement of two individuals (3) fusion of two haploid nuclei (4) rejuvenation

If the thallus of an organism e.g., a fungus is entirely converted into one or more reproductive structure, it is called as (1) eucarpic (2) holocarpic (3) holozoic (4) homothallic

31.

Dikaryon formation is characteristic of (1) ascomycetes and basidiomycetes (2) phycomycetes and basidiomycetes (3) ascomycetes and phycomycetes (4) phycomycetes and zygomycetes

25.

Two species of Amoeba X and Y were kept in fresh water and got adapted. Species X developed contractile vacuole. When both were transferred to sea water and got adapted, both X and Y lost their contractile vacuole. From these observation we conclude that

32.

A fungus contains cells with two nuclei from different genomes. The nuclei do not fuse but divide independently and simultaneously as new cells are formed. It belongs to (1) phycomycetes (2) zygomycetes (3) deuteromycetes (4) basidiomycetes

70

BIOLOGY

33.

What one of the following statement is true ? (1) Toadstool is an edible fungus. (2) Rust fungi are homoecious. (3) Parathecium is fruiting body. (4) In mushroom gills produce basidia.

34.

Match Column I with Column II. Column-I Column-II (Spores) (Organisms) (A) Ascospores p. Diatoms (B) Endospores q. Agaricus (C) Auxospores r. Bacteria (D) Basidiospores s. Yeast t. Nephrolepis (1) A – s, B – r, C – p, D – q (2) A – s, B – p, C – r, D – q (3) A – s, B – p, C – t, D – q (4) A – s, B – t, C – p, D – q

35.

36.

37.

38.

39.

40.

41.

(2) provides protection, anchorage and absorption for the alga (3) provides food for the alga (4) releases oxygen for the alga 42.

Fungi growing on rotten wood are called (1) bracket fungi (2) coral fungi (3) puffballs (4) toadstools

43.

Naked cytoplasm, multinucleated and saprophytic are the characteristics of (1) monera (2) protista (3) fungi (4) slime moulds

44.

An association between roots of higher plants and fungi is called (1) lichen (2) fern (3) mycorrhiza (4) blue green algae

45.

Members of phycomycetes are found in (1) aquatic habitats (2) on decaying wood (3) moist and damp places (4) all of the above

46.

VAM are (1) saprophytic bacteria (3) symbiotic fungi

(2) saprophytic fungi (4) symbiotic bacteria

47.

Phycology is the study of (1) algae (3) bacteria

(2) fungi (4) all the above

48.

Which one of the following statements concerning the algae is wrong ? (1) Most algae are photosynthetic. (2) Algae can be classified according to their pigments. (3) All algae are filamentous. (4) Spirogyra does not produce zoospores.

49.

Which among the following shows that two species of algae are closely related ? (1) They both respire and release CO2. (2) They both found in the same habitat. (3) They both reproduce asexually. (4) They both have same type of pigments.

50.

Yeast is not included in protozoans but in fungi because (1) it has no chlorophyll (2) some fungal hyphae grow in such a way that they give the appearance of pseudomycelium (3) it has eukaryotic organisation (4) cell wall is made up of cellulose and reserve food material is starch

A filament of an alga can be differentiated from that of a fungus as (1) cells are uninucleate in algae whereas they are multinucleate in fungi (2) chlorophyll present in algae and absent in fungi (3) presence of cellulose cell wall and chlorophyllous cells in algae while chitinous cell wall and nonchlorophyllous cells in fungi (4) algae are green and fungi are non-green

51.

Which one of the following pairs is correctly matched (1) Rhizobium – Parasite in the roots of leguminous plants (2) Mycorrhizae – Mineral uptake from soil (3) Yeast – Production of biogas (4) Myxomycetes – Ring worm disease

Digestive system is complete where (1) all the digestive glands are present (2) both anus and mouth are present (3) digestion occurs in the cavity of digestive tract (4) digestion occurs in the individual cells lining the digestive tract

52.

Non-chordates have (1) notocord (2) dorsal tubular nerve blood (3) pharyngeal gills cleft (4) absence of hepatic portal system

According to recent classification system, Mucor is classified under (1) plant kingdom (2) animal kingdom (3) both plant and animal kingdom (4) a separate kingdom Heterothallism means (1) fusion of two gametes from two thalli of opposite strains (2) fusion of two gametes from thalli of similar strain (3) formation of a zygospore partheno-genetically (4) torula stage Which of the following plants and its mode of nutrition is not correctly matched ? (1) Cuscuta – Stem parasite (2) Mucor – Autotroph (3) Orobanche – Root parasite (4) Drosera – Insectivorous Yeast are economically important because they (1) spread plant diseases (2) spread animal diseases (3) are used in tea and tobacco industry (4) are used in wine and baking industry

There exists a close association between the algae and the fungus within a lichen. The fungus (1) fixes the atmospheric nitrogen for the alga

BIOLOGICAL CLASSIFICATION

71

53.

Mycobiont and phycobiont are found in (1) mycorrhiza (2) root (3) lichens (4) blue green algae

54.

Difference between virus and viroid is (1) absence of protein coat in viroid but present in virus (2) presence of low molecular weight RNA in virus but absent in viroid (3) both (1) and (2) (4) none of these

55.

With respect to fungal sexual cycle, choose the correct sequence of events. (1) Karyogamy, Plasmogamy and Meiosis (2) Meiosis, Plasmogamy and Karyogamy (3) Plasmogamy, Karyogamy and Meiosis (4) Meiosis, Karyogamy and Plasmogamy

56.

Viruses belong to kingdom (1) monera (2) protista (3) fungi (4) none of the above

57.

Which of the following statement is false ? (1) TMV has a double-stranded RNA molecule. (2) Most plant viruses are RNA viruses. (3) The bacteriophage has a double-stranded DNA molecule. (4) Most animal viruses are DNA viruses.

58.

Match the following A. B. C. D. (1) (2) (3) (4)

59.

60.

Column-I M13 bacteriophage Rice dwarf virus Cauliflower mosaic virus Polio virus A B C D III I IV II II I III IV III IV II I IV III I II

Column-II I. dsRNA II. ssRNA III. ssDNA IV. dsDNA

Which of the following statement are correct to describe viruses ? I. It is simple and unicellular organisms. II. It contains DNA or RNA and enclosed by protein coat. III. It possesses own metabolic system and respond to stimuli. IV. It maintains genetic continuity and undergo mutations. (1) I and II (2) II and IV (3) II and III (4) I and III Viroids have (1) ssRNA not enclosed by protein coat (2) ssDNA not enclosed by protein coat (3) dsDNA enclosed by protein coat (4) dsRNA enclosed by protein coat

61.

Which of the following pairs have ds RNA ? (1) cauliflower mosaic virus and dahlia mosaic virus (2) polio virus and wound tumour virus (3) would tumour virus and reovirus (4) tobacco mosaic virus and reovirus

62.

Which are mostly anaerobic ? (1) Algae (2) Mosses (3) Fungi (4) All of the above

63.

Which of the following is antifungal antibiotic ? (1) Streptomycin (2) Aureomycin (3) Griseofulvin (4) Chloromycetin

64.

Aflatoxins are produced by (1) viruses (2) bacteria (3) fungi (4) nematodes

65.

Mycorrhiza functions as (1) modified root (2) root hair in adverse conditions (3) organism for vegetative propagation (4) mechanical tissue for support

66.

Perfect stage of fungus means (1) when fungus is perfectly healthy (2) when it produces asexually (3) when it reproduces sexually (4) when it forms perfect resting spores

67.

Diatom frustule/shell is made of (1) silica (2) lime (3) magnesium carbonate (4) any of the above

68.

Amoeba is (1) ammonotelic (3) uricotelic

69.

Archaea differ from eubacteria in one of the following features. (1) They have a rigid wall. (2) Their cell wall lacks peptidoglycan component. (3) They have 16 sRNA. (4) They are very ancient.

70.

Cyanobacteria are (1) autotrophic prokaryotes with characteristic bluegreen pigments. (2) bacteria infecting the cyanophycean algae. (3) viruses infecting blue green algae. (4) cyanopycean members infecting bacteria.

71.

Chemical substance secreted by microorganisms for inhibiting growth of another organism is (1) antibody (2) antiallergic (3) afflatoxin (4) antibiotic--

(2) ureotelic (4) none of these above

72

BIOLOGY

ANSWER KEY EXERCISE 3 : TEST YOURSELF

1.

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(4) Myxomycetes are commonly called true slime moulds. These are saprophytic and their vegetative phase is represented by a free living, mass of protoplasm without walls and produce haploid spores, which are dispersed by air currents, rain and mites.

27.

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31.

(1) In some fungi (ascomycetes and basidiomycetes), an intervening dikaryotic stage (n + n, i.e., two nuclei per

og

EXERCISE 1 : NCERT BASED QUESTIONS

cell) occurs; such a condition is called dikaryon.

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(3) VAM (Vesicular Arbuscular Mycorrhizae) is the mutually beneficial or symbiotic association of a

76.

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78.

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81.

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Polyporus, Ganoderma, Fusarium etc. 44.

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fungus with the root of a higher plant.

102. (4)

103. (2)

104. (1)

105. (4)

106. (1)

107. (2)

108. (1)

109. (2)

110. (1)

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114. (1)

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58.

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118. (4)

119. (4)

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60.

(1) Viroids are small, single stranded, circular RNA

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om

EXERCISE 2 : WINDOW TO COMPETITIVE EXAMS

141. (2)

molecule as genetic material. 59.

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(3)

62.

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63.

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64.

(3)

65.

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66.

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67.

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Chapter

3

Plant Kingdom At a Glance

While going through the chapter pay special attention to the following – Terms –



1.

Phenetics

2.

Cladistics

3.

Algin

4.

Carrageen

5.

Synergids

6.

Antipodal cells

7.

Algology

8.

Floridean starch

9.

Laminarin

10.

Pyrenoids

12.

Frond

11. Fucoxanthin



   

(i)



(ii) Chlorophyceae, phaeophyceae and rhodophyceae. (iii) Monocotyledons and dicotyledons (iv) Haplontic, diplontic, and haplo-diplontic lifecycles. 

Plant kingdom includes eukaryotic, autotrophic or photosynthetic and non-motile organisms.



They have well defined cellulosic cell wall. Plastids are present.



Plant kingdom includes five major plant groups i.e., Algae, Bryophyta, Pteridophyta, Gymnosperms and Angiosperms as proposed by R.H.Whittaker in 1969.



In earlier classifications kingdom plantae also included fungi and members of protista and monera having cell walls.

TYPES OF CLASSIFICATION There are various types of classification in angiospermic plants. 1.

Artificial system of Classification :



All taxonomists, from Aristotle to Linnaeus, classified organisms on the basis of external observable (morphological) characters like structure of floral parts ( number of stamens), root modification, leaf venation etc.



In this system no weightage was given to natural and phylogenetic relationship. Such system is based on one or a few superficial similarities.



This is an arbitrary system of classification. Linnaeus also used such system of classification



This system may also be based upon habit and habitats of the organisms.

Algae



Differences – Isogamous, anisogamous and oogamous fusion.

Types of classi�ication Classes of Algae

Bryophyta

Pteridophyta

Gymnosperm Angiosperm

Plant lifecycle and alternation of generation.

74

BIOLOGY 2.

Natural System of Classification :



It uses more number of characters and is based upon natural affinities using homology and comparative study.



Bentham - Hooker used this system of classification for angiosperms.

3.

Numerical Taxonomy ( Phenetics ) or Quantitative taxonomy :



This system uses numerical methods for evaluating the similarities and differences between the species.



This uses maximum number of characters, without giving extra emphasis on anyone.



Sophisticated calculating machines and computers are used for statistical analysis. This system gives equal importance and weightage to all the characters used for taxonomy.



As this system was first attempted by Adanson (1763), the numerical taxonomy is also known as Adansonian system (The Phenetics is considered to be a better classification as it uses a huge number of comparative features).

4

Phylogenetic Classification (Cladistics) :



This system of classification is based upon evolutionary relationship and uses morphological characters, origin and evolution of the different organisms.



The ‘Family tree’ in this system is called Cladogram.



This system has led to the emergence of new systematics and bio-systematics.



Phylogenetic system of classification was proposed by Hutchinson.



Adolf Engler and K. Prantl, both German Botanists, published ‘Phylogenetic system of classification’ in plants and considered monocots to be the more primitive than the dicot angiosperms.



They published twenty volumes of classification (from algae to angiosperm) in Die Natuerlichen Phlanzenfamilien.

5

Karyotaxonomy :



This system of classification uses information like chromosome number, structure of chromosomes, size and shape of chromosomes and the behaviour of chromosomes during meiosis.

6

Chemotaxonomy :



This system is based on chemical products, particularly secondary metabolites. Various families of plants have been identified on the basis of raphides (Crystals of calcium oxalates).

7.

Experimental taxonomy :



Here the relationship is determined on the basis of genetics, breeding experiments and the effect of captivity.

8.

Bio-chemical taxonomy :



It is based on the bio-chemistry of various chemicals like hormones, pheromones etc.

Eichler (1883) divided plant kingdom into two subkingdoms mainly on the basis of presence or absence of seeds, 

Cryptogamae—Lower plants in which sex organs are hidden and seeds and flowers absent. It includes Thallophytes, Bryophytes, Pteridophytes.



Phanerogamae—Higher plants in which sex organs are evident; seeds present. It includes Gymnosperms and Angiosperms. Engler (1886) divided plants into Thallophyta (plant body thallus like and there is no embryo formation) and Embryophyta (zygote develops into multicellular embryo).

PLANT KINGDOM

75

CLASSIFICATION OF PLANTS

THALLOPHYTA 

It includes Algae, Fungi, Bacteria, Lichens.



In modern system of classification like Whittaker (1969), Fungi, Lichens and Bacteria are excluded from this group and are placed in separate kingdoms.



Thallophytes are simplest seedless, flowerless, non-vascular plants.



The plant body is thallus which is haploid (n) gametophytic and does not show any differentiation into roots, stem or leaves. Vascular system is completely absent. The sex organs are unicellular called gametangia. These are not jacketed by sterile cells.

ALGAE

Connecting Concepts  Morris : Father of algae.



The branch of botany which deals with the study of algae is termed as algology or  M.O.P. Iyenger : Father of Indian phycology.



In Whittaker’s classification, algae are grouped in three kingdom – Monera (blue green  Linnaeus, 1753 : Coined the term algae), Protista (dinoflagellates, diatoms, euglenoids) and plantae (green algae, red algae algae. and brown algae).



Algae are haploid gametophytic, eukaryotic, autotrophic, chlorophyllous, aquatic plants.

 

Phycology.

 They are primary producers of food and occupy 3/4 of the surface Algae consist of thallus like plant body i.e. no differentiation of roots, stem and leaves. of earth and account for 90% of total Algae are plants because they have chlorophyll a, cellulosic cell wall, starch as reserve photosynthesis.

food and absorption of food in liquid form. 

Chlorophyll a, carotenes and xanthophylls occur in all algae. Every algal group has some additional photosynthetic pigments like fucoxanthin and chlorophyll c in brown algae, phycobilins in red algae, chlorophyll b and β-carotene in green algae.



Every algal group has a specific reserve food, e.g., floridean starch (red algae), laminarin (brown algae), starch (green algae).



Asexual reproduction occurs by unicellular mitospores. Sex organs are unicellular nonjacketed and called gametangia.



In multicellular reproductive organs (in some brown algae), all the cells are fertile and take part in reproduction. There is no jacket of sterile cells surrounding the reproductive organs.



Fertilization requires water.



Zygote sheds and develops into perennating thick walled zygospore.



Zygote never develops into embryo.



True alternation of generations is absent (exception— Ectocarpus that shows isomorphic alternation of generations).



Life cycle mostly haplontic type.



Algae do not require mechanical tissue because buoyancy holds them upright.



The size ranges from the microscopic unicellular forms like Chlamydomonas, to colonial forms like Volvox and to the filamentous forms like Ulothrix and Spirogyra.

76

BIOLOGY Reproduction Vegetative Asexual

Sexual

By fragmentation, each fragment develops into a thallus. By spores like zosspores, aplanospores, autospores, akinete and endospoxs. The most common is zoospore, they are flagellated. Fusion of gametes Isogamous Anisogamous Oogamous fusion : fusions : Gametes fusion : Gametes This is a fusion between can be flagellated or are dissimilar one large and non-motile non-flagellated but in size. e.g., female gamete and one similar in size. Chlamydomonas small but motile male e.g., Ulothrix, bravni. gamete. Chlamydomonas, E.g. Volvox, Fucus debaryana. Chlamydomonas coccilera.

Economic Importance of Algae 

At least a half of the total carbon dioxide fixation on earth is carried out by algae through photosynthesis.



They are primary producers of energy-rich compounds which form the basis of the food cycles of all aquatic animals.



Certain marine brown and red algae produce large amounts of hydrocolloids (water holding substances), e.g., algin (brown algae) and carrageen (red algae) which are used commercially.



Agar, one of the commercial products obtained from Gelidium and Gracilaria are used to grow microbes and in preparations of ice-creams and jellies.



Chlorella and Spirullina are unicellular algae, rich in proteins and are used as food supplements by space travellers.



The algae are divided into three main classes : Chlorophyceae Algae

Phaeophyceae Rhodophyceae

Chlorophyceae (Green Algae) 

Green algae are mostly freshwater (Spirogyra, Ulothrix, Chara, Zygnema, Volvox, Chlamydomonas) and hardly 10% are marine (e.g., Acetabularia, Ulva, Caulerpa etc.).



Plant body may be unicellular (e.g., Chlamydomonas), colonial (e.g., Volvox), or filamentous (Spirogyra, Ulothrix).



They are green due to dominance of pigments chlorophyll a and b.



The pigments are localised in chloroplasts. The chloroplasts may be discoid, plate-like, reticulate, cup-shaped, spiral or ribbon-shaped in different species.



Starch is reserve food that is stored as sheets in pyrenoids, present in the chloroplast.



They have rigid cell wall made of cellulose and pectose.



Vegetative reproduction usually takes place by fragmentation.



Asexual reproduction takes place by zoospores produced in zoosporangia.

PLANT KINGDOM

77



Sexual reproduction involves formation of haploid gametes, their fusion to form diploid zygote, followed by meiosis to form meiospores which on germination produce new haploid gametophytic plant.



The sexual reproduction shows considerable variation in the type and formation of sex cells and it may be isogamous, anisogamous or oogamous.



Green algae are regarded as ancestor of land plants because both green algae and land Connecting Concepts plants possess chlorophyll a, b, β carotenoids, cellulosic cell wall and starch as reserve food.  The Sargasso sea (called oceanic Common Examples : Chlamydomonas, Volvox, Ulothrix, Spirogyra and Chara

desert) in North Atlantic is named so due to abundant occurrence of free floating Sargassum fluitans which is a menace to shipping.  Algae Chlamydomonas snowiae, and C. nivalis inhabit ice or snow to make it appear red.  Red sea is part of the Mediterranean sea, where a blue green algae Trichodesmium erythrae grow on surface and imparts red colour.

Fig. 3.1 Green algae

Phaeophyceae (Brown Algae) 

These are brown coloured marine eukaryotic algae. They show great variation in size and forms.



They range from simple branched, filamentous forms ((Ectocarpus) to profusely branched forms as represented by Kelps, which may reach a height of 100 metres (largest marine plants).



They possess chlorophyll a, c, carotenoids and xanthophylls and a characteristic brown pigment fucoxanthin, Chl b is absent.



They vary in colour from olive green to various shades of brown depending upon the amount of the xanthophyll pigment, fucoxanthin, present in them.



Food is stored as complex carbohydrates, which may be in the form of laminarin or mannitol.



The vegetative cells have a cellulosic wall usually covered on the outside by a gelatinous coating of algin. This prevents drying of plant during low tide; freezing of plant in water in winter as well protect cells when waves beat plant against rocks.



The protoplast contains, in addition to plastids, a centrally located vacuole and nucleus.



Thylakoids are found in groups of three to five in cytoplasm (not in chioroplast) as chromatophores.



Pyrenoids are naked.



The plant body is usually attached to the substratum by a holdfast, and has a stalk, the stipe and leaf like photosynthetic structure – frond.

78

BIOLOGY

Fig. 3.2 Brown algae



Vegetative reproduction takes place by fragmentation.



Asexual reproduction in most brown algae is by biflagellate zoospores that are pear shaped and have two unequal laterally attached flagella.



Sexual reproduction may be isogamous, anisogamous or oogamous. Union of gametes may take place in water or within the oogonium (oogamous species). The gametes are pyriform (pear-shaped) and bear two laterally attached flagella.



Common brown algae are Ectocarpus, Dictyota, Laminaria, Fucus and Sargassum.

Rhodophyceae (Red Algae)

Check Point Fill in the blanks : (i) Red colour of red algae is due to pigment _________. (ii) The largest unicellular and uninucleate algae is _________. (iii) In brown algae, the plants has three parts _________, _________ and _________. (iv) Agar is commercially obtained from _________. (v) In brown algae, food is store as _________.

Fig. 3.3 Red algae



They are commonly called red algae because of the predominance of the red pigment, r-phycoerythrin in the body.



Majority of the red algae are marine with greater concentrations found in the warmer areas. They occur in both well-lighted regions close to the surface of water and also at great depths in oceans where relatively little light penetrates.



When growing deep, red algae appear red due to excess formation of r-phycoerythrin that captures short wavelength (blue green part of visible spectrum) which is able to reach the maximum depth in water. These algae, therefore, reach the maximum depth (30-90 mt) in sea where no other photosynthetic organism grows. They appear greenish/bluish green or purple when growing near the surface of the sea due to little production of phycoerythrin. This property of colour change is called chromatic adaptation.

PLANT KINGDOM

79



The thalli of most of the red algae are multicellular. Some of them have complex body organisation.



Batrachospermum is only fresh water red alga found growing in well aerated water but it is not red.



The food is stored as floridean starch which is very similar to amylopectin and glycogen in structure.



The red algae reproduce vegetatively by fragmentation.



They reproduce asexually by non-motile spores and sexually by non-motile gametes.



Flagellated cells are totally absent in life cycle.



Sexual reproduction is oogamous and accompanied by complex post fertilisation developments.



The common members are Polysiphonia, Porphyra, Gracilaria and Gelidium.

Divisions of Algae and their main characteristics Classes

Common name

Major pigments

Stored food

Cell wall

Flagellar number and position of insertions

Habitat

Chlorophyceae Green algae

Chlorophyll Starch a,b

Cellulose 2-8, equal, apical

Fresh water, brackish water, salt water

Phaeophyceae

Brown algae

Chlorophyll Mannitol, Cellulose 2, unequal, a,c, fucox- laminarin and algin lateral anthin

Fresh water (rare) brackish water, salt water

Rhodophyceae

Red algae Chlorophyll Floridean Cellulose Absent a,d, dd, phyco- starch erythrin

Fresh water (some) brackish water, salt water (most)

BRYOPHYTES The Amphibians of the Plant Kingdom  Bryology : Study of bryophytes.  Father of Indian Bryology : S.R. Kashyap  Father of Bryology : Hedwig  Bryophytes originated in ordovician period about 420-500 million years ago.  Age of Bryophytes : Silurian period of Palaeozoic era.  They usually occur in damp, humid and shaded localities.  The plant body of bryophytes is more differentiated than algae. It is thallus-like, prostrate or erect, and attached to the substratum by unicellular or multicellular rhizoids. They lack true roots, stem or leaves.  They may possess root-like, leaf-like or stem-like structures.  Bryophytes are adapted to grow under land conditions by having rhizoids for fixation; a waxy covering on epidermis to reduce loss of water and protect against dessication; stomata or air pores for gaseous exchange; multicellular jacketed sex organs to protect gametes against drying effects of air and retention of zygote inside archegonium to provide nourishment to developing embryo.  Bryophytes are fundamentally terrestrial plants but they require water for dehiscence of antheridia, liberation and swimming of antherozoids, fertilization of egg, opening of archegonial neck and entry of sperms into the archegonium. Because of such peculiar habitat they have been most appropriately called the amphibians of the plant kingdom.  Bryophytes completely lack vascular tissue system and they absorb water by general body surface.  The main plant body of the bryophyte is haploid. It produces gametes, hence called gametophyte. Gametophyte is dominant over sporophyte.

Connecting Concepts  Bryophytes do not grow tall : Bryophytes seldom grow tall. Average size is hardly 5-6 cm. Greater heights are rare because bryophytes : (i) Do not have roots which are required to absorb water from the soil and provide proper fixation in the soil; (ii) Absence of an efficient internal transport system or vascular system; (iii) Lack mechanical tissues.

80

BIOLOGY 

Gametophyte is green, branched, haploid, long lived and independent where as sporophyte is diploid, short lived and dependent upon gametophyte.



The sex organs in bryophytes are multicellular.



The male sex organ is called antheridium. They produce biflagellate motile antherozoids.



The female sex organ called archegonium is flask-shaped and produces a single nonmotile egg.



The antherozoids are released into water where they come in contact with archegonium. An antherozoid fuses with the egg to produce the zygote. Zygotes do not undergo reduction division immediately. They produce a multicellular body called sporophyte.



The sporophyte is not free-living but attached to the photosynthetic gametophyte and derives nourishment from it. Some cells of the sporophyte undergo reduction division (meiosis) to produce haploid spores in sporogonium. The sporogonium is short lived and differentiated into either foot, seta and capsule or capsule only.



All spores are alike (homosporous).



These spores germinate to produce gametophyte.

 

Asexual reproduction absent. Vegetative reproduction by fragmentation of thallus, tubers (Riccia, Anthoceros), gemmae (Funaria, Marchantia), protonema (mosses), adventitious branches (Pellia), progressive death and decay of posterior older region of thallus, persistent growing apices (liverworts) Sexual reproduction is oogamous. Male gamete is motile whereas female gamete is non-motile. Archegonia attract sperms by secreting mucilage rich in potassium salts/ proteins/sucrose.



Fig. 3.4 Life cycle of Bryophyte

Economic Importance of Bryophytes   

Some mosses provide food for herbaceous mammals, birds and other animals. Species of Sphagnum, provide peat that have long been used as fuel, and because of their capacity to hold water used as packing material for trans-shipment of living material. Mosses along with lichens are the first organisms to colonise rocks and hence, are of great ecological importance. They decompose rocks making the substrate suitable for the growth of higher plants. In other words, they initiate the conversion of rocks into soil.

PLANT KINGDOM 

81

Since mosses form dense mats on the soil, they reduce the impact of falling rain and prevent soil erosion.

The Bryophytes are divided into following classes: Liverworts Bryophytes Mosses

Liverworts (Marchantia)

Connecting Concepts  Gold Mines of Liverworts. Western

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Liverworts usually grow in moist, shady habits such as banks of streams, marshy ground, Himalayas. damp soil and bark of trees.

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The plant body is haploid (n), gametophytic, small, dorsoventrally flattened, thallose, dichotomously branched fixed by unicellular and unbranched rhizoids.

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On the dorsal side, gemma cups are found. In gemma cups, asexual buds gemmae are formed.

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On the ventral side scales are found for retaining moisture and protecting growing apex. Absorption of water by general surface of thallus.

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Internally thallus is differentiated into upper photosynthetic and lower storage region; chlorophyllous cells of thallus are without pyrenoid.

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Asexual reproduction in liverworts takes place by fragmentation of thalli, or by the detachment of gemmae from parent body and its germination to form new individual.

Check Point Name any one function of these structures : (i) Gemmae (ii) Rhizoids (iii) Sporogonium (iv) Seta (v) Capsule.

Fig. 3.5 Bryophytes Marchantia (a) Female thallus

(b) Male thallus (c) Funaria gametophyte and sporophyte (d) Sphagnum

82

BIOLOGY 

During sexual reproduction, male and female sex organs are produced either on the same or on different thalli. The sporophyte is differentiated into a foot, seta and capsule. After meiosis, spores are produced within the capsule. These spores germinate to form free-living gametophytes.

Moss (Funaria) Mosses are either monoecious or dioecious. The common Indian species Funaria hygrometrica is monoecious. Mosses are found in moist, shady places in patches on damp soil, moist rocks, burnt humid soil, damp walls or on tree trunks. Gametophyte : The main body of Funaria is gametophyte and is of two forms •

Juvenile form (Creeping protonema) : Protonema is a green filamentous, branched structure.

•

From protonema some branches which grow below the substratum are produced. These branches are without chloroplasts, known as rhizoidal branches. They fix the protonema in the soil and help in absorption of water and minerals. Green branches develop buds of leafy gametophores.

•

Adult form (Leafy gametophore) : This is the main plant body of moss, consisting of a small erect axis ‘stem’ surrounded by spirally arranged ‘leaves’ and numerous rhizoids at the base. Leafy gametophore develops from buds produced on protonema.

Reproduction 

Vegetative reproduction : The gametophyte reproduces vegetatively by fragmentation of primary protonema, secondary protonema, gemmae and bulbils.

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Sexual reproduction : Funaria is monoecious and autoicous. i.e. antheridia and archegonia occur on different branches of the same plant.

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The male branch is the main branch and develops first. The antheridia mature first i.e., it is protandrous. The sex organs are borne on the apices of fertile branches called gametophore or receptacles. The receptacle bearing antheridia called antheridiophore and that bearing archegonia are called archegoniophore.

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Sporophyte : The diploid zygote develops into spore producing plant called sporophyte. Mature sporophyte is differentiated into foot, seta and capsule.

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Foot : The foot remains embedded in the apical tissue of the archegonial head and obtains nourishment from it. It functions as anchorage and absorbing organ.

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Seta: It is long, slender, stalk like structure bearing capsule at the top.

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Capsule: The capsule is a pear shaped, green, yellow or orange erect or pendent structure. Its function is production and dispersal of spores. It consists of 3 parts i.e., apophysis, theca and operculum •

Apophysis : It is basal sterile region.

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Theca : It is central fertile region. It consists of spore sac bearing numerous diploid spore mother cell that divide to give large number of haploid spores.

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Operculum : It is upper region of capsule enclosing peristome.

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Just below the operculum lies the peristome consisting of two rings of long conical teeth one within the other. Each ring of peristome possesses sixteen teeth.

Dehiscence of Capsule : The spores are dispersed due to hygroscopic movements of outer ring (exostome) of peristomial teeth. The inner ring (endostome) of peristomial teeth do not show hygroscopic movements. Germination of Spores : On getting suitable moist substratum, the spore germinates to produce a young filamentous stage of gametophyte called protonema. Common Examples : Funaria, Polytrichum and Sphagnum.

PLANT KINGDOM

83

Fig. 3.6 Life Cycle of Funaria

PTERIDOPHYTA 

The pteridophytes are found in cool, damp, shady places though some may flourish well in sandy-soil conditions.

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Evolutionarily, they are the first terrestrial plants to possess vascular tissues – xylem and phloem. So known as vascular cryptogams. They are flowerless and seedless plants.

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The main plant body is a sporophyte which is differentiated into true root, stem and leaves. These organs possess well-differentiated vascular tissues. A cambium is altogether absent. In xylem trachea are absent and in phloem companion cells are absent.

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Primary root is short lived. It is replaced by adventitious roots.

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The leaves in pteridophyta are small (microphylls) as in Selaginella or large (macrophylls) as in ferns.

84

BIOLOGY Connecting Concepts

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 Theopharastus is father of  pteridophytes, botany and ecology.  Selaginella bryopteris is hasanpadi  of Ayurved or Sanjivani Booti  Selaginella rupestris is bird’s nest moss.  Lycopodium is famous as Christmas  green.  Sorrow of Kashmir : The aquatic weed Salvinia.

Pteridophytes show origin and evolution of stele (i.e., vascular tissue, pericycle and pith). Stem is usually underground rhizome or an erect trunk as in tree ferns. Leaves are large (megaphyllous) and variously shaped. The sporophytes bear sporangia that are subtended by leaf-like appendages called sporophylls. In some cases sporophylls may form distinct compact structures called strobili or cones (Selaginella, Equisetum). The sporangia produce spores by meiosis in spore mother cells. Sporangia are borne on abaxial side of fertile leaves. These sporangia are borne either singly or in groups, called sori (sing sorus). The spores germinate to give rise to inconspicuous, small but multicellular, free-living, mostly photosynthetic thalloid gametophytes called prothallus.

 Ophioglossum reticulatum, commonly called Adders Tongue Fern, has maximum number of chromosomes in plantae, i.e., 2n = 1262.  Azolla-Anabaena, show symbiosis, used as biofertilizer in rice fields.  Smallest Pteridophyte : Water Fern Azolla.  Tallest Pteridophyte : Alsophila.  Rootless Pteridophyte : Salvinia. Root like structures are modified leaves.  Pteridology : Study of pteridophytes.  Xylem vessels are present in the stem of Equisetum.

Fig. 3.7 Pteridophytes

 Isoetes is a pteridophyte with  secondary growth commonly called Quillwort.  Pteridophytes originated in silurian  period of palaeozoic era.  Golden age of pteriodphytes is  devonian period.

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These gametophytes require cool, damp, shady places to grow. Because of this specific restricted requirement and the need of water for fertilisation, the spread of living pteridophytes is limited and restricted to narrow geographical regions. The gametophytes bear male and female sex organs called antheridia and archegonia, respectively. Antheridia (male sex organs) produce motile sperms (biflagellated in Selaginella and multiflagellated in ferns). Archegonia (female sex organs) are sessile, flask shaped with a neck and swollen venter. Neck is made up of 4 vertical rows of cells, each row with 2-6 cells. Venter is embedded and has no wall of its own and encloses a non motile ventral canal cell and egg cell (oosphere). Sexual reproduction is oogamous. Water is required for transfer of antherozoids – the male gametes released from the antheridia, to the mouth of archegonium. Fusion of male gamete with the egg present in the archegonium result in the formation of zygote which represents the first cell of sporophyte. Zygote thereafter produces a multicellular well-differentiated sporophyte which is the dominant phase of the pteridophytes. Life cycle is diplohaplontic; alternation of generations is heteromorphic type. Genera like Selaginella and Salvinia which produce two kinds of spores macro (large) and micro (small) spores, are known as heterosporous. The megaspores and microspores germinate and give rise to female and male gametophytes, respectively. The female gametophytes in these plants are retained on the parent sporophytes for variable periods. The development of the zygotes into young embryos take place within the female gametophytes. This event is a precursor to the seed habit considered an important step in evolution.

PLANT KINGDOM

Classification of Pteridophytes

85 Connecting Concepts

 Apospory : Formation of gametophyte directly from cells of a sporophyte Subphylum I – Psilophyta without the formation of spores is  These plants represent rootless sporophytes which mainly constitute fossils. The example called apospory (Gk. apo – without, of living form is Psilotum. sporos–spores). Apospory is induced  Vascular tissue present only in stem, rhizoids are present for absorption of water and by excess salts, injury and dimlight. Aposporous gametophyte is diploid. minerals. It produces diploid gametes which Subphylum II – Lycophyta can introduce polyploidy in the race.  These are club mosses, differentiated into root, stems and leaves. Apospory is also means of shortening life cycle by producing diploid  Vascular tissue found in all organs of plant. sporophytes parthenogenetically from Subphylum III – Arthophyta diploid oospheres.

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Pteridophytes have been divided into the four following subphyla :

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The horsetail or scouring rushes belong to this group.

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Silica particles are deposited in their stem e.g., Equisetum (horsetail).

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Gymnosperms include medium-sized trees or tall trees and shrubs. One of the gymnosperms,  Tallest Gymnosperm : Sequoia sempervirens (111.6 m) commonly called the giant redwood tree Sequoia is one of the tallest tree species.

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Most plants are perennial and woody. Plants posses well developed tap root system.

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Roots in some genera have fungal association in the form of mycorrhiza (Pinus ( ), while  Smallest Gymnosperm and Smallest in some other (Cycas) small specialised roots called corolloid roots are present. It is Cycad : Zamia pygmia (26 cm). associated with N2 – fixing cyanobacteria.

 Apogamy : Formation of sporophyte directly from gametophyte without Subphylum IV – Filicophyta involving formation and fusion of gametes is called apogamy (Gk.  Usually fan shaped leaves apo – without, gamos – marriage).  Stems usually rhizome It is induced by partial desiccation,  Homosporus e.g., Dryopteris, Pteris or Heterosporous e.g., Marsilea. ageing, strong light, high temperature, presence of sugars and ethylene. GYMNOSPERMS Haploid sporophytes do not survive. Therefore, apospory is successful only  Theophrastus in 300BC introduced the term gymnosperm. if the sporophyte develops from diploid  Gymnosperms are plants which bear naked seeds i.e., the ovules and the seeds that develop gametophyte formed either through from these ovules after fertilization are not enclosed in fruit wall. apospory or diploid spores produced due to failure of some division prior to  They acts as a bridge between pteridophyta and angiosperms. sporogenesis.  Gymnosperms are represented by only 900 species of which 500 species are conifers.

Red Douglos Fir or Red Wood Tree or Californian Fir.

 Largest Cycad : Macrozamia (10 m)

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Vascular tissues are arranged in vascular bundles. In most gymnosperms, secondary growth  Father of Forest : Sequoia sempervirens occurs and annual rings are distinct. The xylem is without vessels (except in Gnetales) and (Redwood Tree). phloem lacks companion cells.

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The stems are unbranched (Cycas)) or branched ((Pinus, Cedrus). The leaves may be simple or compound.

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In Cycas the pinnate leaves persist for a few years. The leaves in gymnosperms are welladapted to withstand extremes of temperature, humidity and wind.

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In conifers, the needle-like leaves reduce the surface area. Their thick cuticle and sunken stomata also help to reduce water loss.

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The gymnosperms are heterosporous; they produce haploid microspores and megaspores. The two kinds of spores are produced within sporangia, borne on sporophylls. These are arranged spirally along an axis to form compact strobili or cones in order to protect their ovules.

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Male Strobili : The strobili bearing microsporophylls and microsporangia are called male strobili. The microspores develop into a male gametophytic generation which is highly reduced and is confined to only a limited number of cells. This reduced gametophyte is called a pollen grain. The development of pollen grains takes place within the microsporangia.

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Female Strobili. The cones bearing megasporophylls with ovules or megasporangia are called macrosporangia or female strobili.

86

BIOLOGY Connecting Concepts

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 Ephedra has the largest pollen  chamber.  Cycas, Ginkgo and Metasequoia are  living fossils.  None of the gymnosperm is annual and herbaceous.

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It bears two or more archegonia or female sex organs. The multicellular female gametophyte is also retained within megasporangium.

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In gymnosperms male and female gametophytes do not have an independent free-living existence. They remain within the sporangia.

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The pollen grain is released from the microsporangium. They are carried in air currents and come in contact with the opening of the ovules borne on megasporophylls.

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The pollen tubes, carrying the male gametes, grow towards archegonia in the ovules and discharge their contents near the mouth of the archegonia.

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Following fertilisation, zygote develops into an embryo and the ovules into seeds. These seeds are not covered.

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Usually polyembryony is found in seed although ultimately only one embryo survives.

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Archegonia lack neck canal cells.

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Embryo bears two as in Cycas or more (10-11 in Pinus) cotyledons.

 Largest Egg Cell : Cycas

 Double Fertilization. It is absent in gymnosperms but present in Ephedra.

The megaspore mother cell is differentiated from one of the cells of the nucellus. The nucellus is protected by envelopes and the composite structure is called an ovule. The ovules are borne on megasporophylls which may be clustered to form the female cones. The megaspore mother cell divides meiotically to form four megaspores. One of the megaspores enclosed within the megasporangium (nucellus) develops into a multicellular female gametophyte known as endosperm. Thus endosperm is pre fertilization tissue in gymnosperm.

 Largest Ovule : Cycas

 Cycas as living fossil : Cycas is a living representative of once a large group of gymnosperms which has became largely extinct. It is unable to compete with more evolved angiosperms except in a few selected arid localities where other plants do not flourish. Its primitive characters include (i) Slow growth; (ii) Shedding of seed when the embryo is still immature; (iii) Little secondary growth; (iv) Leaf-like megasporophylls; (v) Flagellate sperms even when pollen tube is present; (vi) Persistent leaf bases; (vii) Circinate ptyxis; (viii) Arrangement of microsporangia in ill-defined sori.

There is no female cone in Cycas.

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 Ciliated Sperms : Cycas and Ginkgo

 Largest Antherozoid : Cycas.

The male or female cones or strobili may be borne on the same tree ((Pinus) or on different trees (Cycas).

Classification of Gymnosperms

 No archegonium is Gnetum and Gifford and Foster in 1989 divided gymnosperms into seven major taxas.Division Welwitschia.

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 Ephedra. It is connecting link between  Angiosperms and Gymnosperms.

Progymnospermatophyta (extinct). Pteridospermatophyta (extinct).

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Cycadophyta (plants are called cycads)

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Cycadeoidophyta (extinct).

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Ginkgophyta (extinct except maiden hair tree – Ginkgo biloba).

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Coniferophyta (extinct and living plants are commomly called conifers).

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Gnetophyta (living plants close to angiosperms in having Gnetalian vessels and flower like arrangement of sporophylls).

Check Point State True or false: 1. In gymnosperm ovules change into seeds after fertilization. 2. Endosperm is female gametophyte in Cycas Cycas. 3. Two or more archaegonia act as female sex organ in gymnosperm. 4. Gymosperms are mostly shrubs and ephemerals (short lived). 5. Archegonia lack neck canal cells in Cycas. Fig. 3.8 Cycas circinalis : (A) Female plant, (B) Male plant

PLANT KINGDOM

ANGIOSPERMS (FLOWERING PLANTS) 

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Angiosperms are most dominant and most evolved plants on this earth, appeared about 130 million years ago in jurassic (dicot plant) and cretaceous (monocot plants) period of mesozoic era. Tertiary period of coenozoic era is called as Age of angiosperms. Angiosperms are found in every habitat. They constitute more than 50% of total plants on this earth. Angiosperms are seed bearing, flowering vascular plants in which seeds are enclosed in fruits. The term angiosperm means ‘enclosed seeds’ as seeds (ovules) are found enclosed in the ovary wall. Instead of cone, angiosperms bear flowers. The flower is the most characteristic structure of the angiosperms. Flower is defined as a modified shoot meant essentially for the reproduction of the plant. The flower usually develops as a branch from a bud, growing in the axil of a small leaflike structure known as bract. A stalk called pedicel, supports the flower in the axil of the bract. The upper swollen end of the pedicel called receptacle or thalamus, bears all the floral parts. A typical angiospermic flower consists of 4 whorls, viz., calyx, corolla, androecium and gynoecium. Both, calyx and corolla are known as accessory or helping whorls. The androecium and gynoecium are called reproductive or essential whorls. Androecium (stamen) is microsporophyll and gynoecium (carpel) is megasporophyll. Megasporophyll is differentiated into ovary, style and stigma. Angiosperms lack both archegonia and antheridia. The archegonium is replaced by gynoecium (pistil) and antheridium by pollen tube. Flowers are adapted for various modes of pollination by birds, air, water, insects, etc. The outer most axillary whorl of the flower is the calyx, represented by the sepals. Corolla is the second whorl of flower present inner to calyx and is composed of petals. The bright color of the petals combined with the scent of essential oils present in some flowers make the flower highly attractive to insects which act as agents for pollination. The angiosperms are an exceptionally large group of plants occurring in wide range of habitats. They range in size from tiny, almost microscopic Wolffia to tall trees of Eucalyptus (over 100 metres). They provide food, fodder, fuel, medicines and several other commercially important products. The male sex organs in a flower is the stamen. Each stamen consists of a slender filament with an anther at the tip. The anthers after meiosis, produce pollen grains. The female sex organs in a flower is the pistil or the carpel. Pistil consists of an ovary enclosing one to many ovules. Within ovules are present highly reduced female gametophytes termed embryosacs. The embryo-sac formation is preceded by meiosis. Hence, each of the cells of an embryo-sac is haploid. Each embryo-sac has a three-celled egg apparatus – one egg cell and two synergids, three antipodal cells and two polar nuclei. The polar nuclei eventually fuse to produce a diploid secondary nucleus. Pollen grain shed at 2-3 celled stage after dispersal from the anthers, are carried by wind or various other agencies to the stigma of a pistil. This is termed as pollination. The pollen grains germinate on the stigma and the resulting pollen tubes grow through the tissues of stigma and style and reach the ovule. The pollen tubes enter the embryo-sac where two male gametes are discharged. One of the male gametes fuses with the egg cell to form a zygote (syngamy). The other male gamete fuses with the diploid secondary nucleus to produce the triploid primary endosperm nucleus (PEN) known as triple fusion. Because of the involvement of two fusions, this event is termed as double fertilisation, and event unique to angiosperms. The zygote develops into an embryo (with one or two cotyledons) and the PEN develops into endosperm which provides nourishment to the developing embryo.

87 Connecting Concepts  Tallest angiosperm : Eucalyptus regnans, around 114 m.  Marine angiosperm : Zostera marina and Thalassia.  National Tree of India : Ficus religiosa, i.e., Peepal or Enlightment Tree or Bodh Tree.  Flame of the Forest : Butea monosperma due to the presence of reddish flowers.

88

BIOLOGY The synergids and antipodals degenerate after fertilisation. During these events the ovules develop into seeds and the ovaries develop into fruit. A fruit is a ripened ovary. The ovary wall enlarges due to cell division and cell enlargement and is termed the pericarp. In fleshy fruits, the pericarp is often differentiated into epicarp, mesocarp and endocarp. A true fruit is one which develops directly from an ovary. Sometimes other parts of the flower such as thalamus, sepals, etc. become a part of the fruit. Such fruits are termed false, spurious or pseudocarp, as in cashew-nut, apple, strawberry, etc. They are divided into two classes : the dicotyledons and the monocotyledons. The dicotyledons are characterised by having two cotyledons in their seeds while the monocotyledons have only one. Characteristics features of dicot & monocot The dicotyledons are characterised by seeds having two cotyledons, reticulate venations in leaves, and tetramerous or pentamerous flowers i.e., having four or five members in each floral whorls, concentric arrangement of tissues in stem, open, conjoint and collateral vascular bundles in stem, secondary growth present, less than 8 radial vascular bundles in root, reticulate venation in leaves (exception Calophyllum, Corymbium), tetramerous or pentamerous flowers e.g., Eucalyptus, Mustard, Sunflower, Rose, Cotton, Apple. Number of dicot species is 200,000. The monocotyledons on the other hand are characterised by single cotyledonous seeds, parallel venation in leaves, and trimerous flowers having three members in each floral whorls, scattered, closed, collateral and conjoint vascular bundles in stem, vascular bundles with a bundle sheath, more than 8 radial vascular bundles in the root, parallel venation in leaves (exception Colocasia, Alocasia, Smilax) e.g., grasses, cereals, orchids, lilies, palms, banana, sugarcane, bamboos. Some 50,000 species.

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Differences between Dicotyledons and Monocotyledons S.No. Dicotyledons 1. The plants have two cotyledons. 2.

Leaves have reticulate venation.

3.

Stomata are generally kidney-shaped.

Monocotyledons The plants have one cotyledon. Leaves possess parallel venation.

5.

Stomata are commonly dumb-bell shaped. Tap root system is more common. Adventitious roots are more common. Adventitious roots are less common. Flowers are tetramerous or pentamerous. Flowers are trimerous.

6.

Pollen grains are generally tricolpate.

7.

Stems have concentric arrangement of Concentric arrangement of tissues is tissues. absent.

8.

In stem the vascular bundles are arranged The vascular bundles are scattered in the in a single ring. stem.

9.

Vascular bundles are without bundle In stem, each vascular bundle is covered sheath in the stem. by a sheath of generally sclerenchyma.

10.

Vascular bundles of the stem are conjoint, Vascular bundles of the stem are conjoint, collateral and open. collateral and closed.

11.

Vessels are polygonal.

12.

Stem shows secondary growth.

4.

Pollen grains are generally monocoplate.

Vessels are rounded or oval in T.S.

13.

Secondary growth is absent with some exceptions. In root the vascular bundles are less than 8. In root the vascular bundles are more than 8.

14.

Root is generally devoid of pith.

A pith is present in the centre of root.

15.

Secondary growth occurs in the root.

Secondary growth is absent with some exceptions.

PLANT KINGDOM

89

Check Point Fill in the blanks : 1. A flower has sepals, petals _______ and _______. 2. Trimerous condition of floral whorl is characteristics of _______. 3. One of male gamete fuses with secondary nucleus to form _______. This is known as _______. 4. In dicotyledonous root, vascular bundles are _______ than eight. 5. Fruit is ripened _______.

Fig. 3.9 Life cycle of an Angiospermic plant

Fig. 3.10 Diagrammatic representation of life history of an Angiospermic plant

90

BIOLOGY

PLANT LIFE CYCLE AND ALTERNATION OF GENERATION 

In plants, both haploid and diploid cells can divide by mitosis. This ability leads to the formation of different plant bodies – haploid and diploid.

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The haploid plant body produces gametes by mitosis. This plant body represents a gametophyte. Following fertilization, the zygote also divide by mitosis to produce a diploid sporophytic plant body.

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Haploid spores are produced by this plant body by meiosis. These in turn divide by mitosis to form haploid plant body once again.

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Thus, life cycle of any sexually reproducing plant consists of two morphological phases i.e., haploid gametophyte and diploid sporophyte that regularly alternate with each other, this phenomenon is termed as alternation of generation.

However life cycles in different plant groups differ in following manner: Haplontic life cycle: •

There is single dominant vegetative phase i.e., haploid gametophyte which is free living photosynthetic phase. It produces gametes that are fused to form zygote.

•

Meiosis in the zygote at the time of its generation results in the formation of haploid spores called meiospores. These meiospores divide mitotically to form gametophyte.

•

Thus, in haplontic life cycle there is no true alternation of generation as sporophytic generation is represented only by one celled zygote. There is no free living sporophyte.

•

This life cycle is found in algae like Chlamydomonas,Volvox, Ulothrix, Spirogyra.

Diplontic life cycle: •

In diplontic life cycle, diploid sporophyte is dominant vegetative phase. The sporophyte is independent photosynthetic phase of the plant.

•

It bears sex organs that produce gametes through meiosis. These gametes fuse to form zygote which again gives rise to sporophytic plant through mitosis.

•

Here gametophytic phase is represented haploid gametes only. Thus, in diplontic life cycle also there is no true alternation of generation.

•

This type of life cycle is found in all seed bearing plants i.e., gymnosperm and angiosperm. Alga Fucus shows diplontic life cycle.

Haplo-diplontic life cycle: •

This is intermediate condition where both phases are multicellular and often free living.

•

The haploid gametophyte produce gametes in sex organs. The gametes fuse to form zygote which on germination give rise to diploid sporophyte.

•

The diploid sporophyte produces spores after meiosis. These spores on germination gives rise to gametophytic phase.

•

Thus it represents true alternation of generation. This type of life cycle is found in bryophytes, pteridophytes and in some algae like Ectocarpus, Polysiphonia.

PLANT KINGDOM

Fig. 3.11 Life cycle patterns : (a) Haplontic (b) Diplontic (c) Haplo-diplontic

91

92

BIOLOGY

EXERCISE - 1 | NCERT BASED QUESTIONS

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In angiosperms, functional megaspore develops into (1) embryo sac (2) ovule (3) endosperm (4) pollen sac Peat Moss is used as a packing material for sending flowers and live plants to distant places because (1) it is hygroscopic (2) it reduces transpiration (3) it serves as a disinfectant (4) it is easily available Which one of the following is a living fossil ? (1) Pinus (2) Opuntia (3) Ginkgo (4) Thuja Blue-green algae belong to (1) eukaryotes (2) prokaryotes (3) rhodophyceae (4) chlorophyceae Bioindicators are (1) lichens tracing the presence of pollution (2) fossil lichens (3) special type of litmus paper (4) none of the above

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2.

5.

sp

Bryophytes are amphibians because (1) they require a layer of water for carrying out sexual reproduction (2) they occur in damp places (3) they are mostly aquatic (4) all of the above Pteridophytes differ from mosses/bryophytes in possessing (1) independent gametophyte (2) well developed vascular system (3) archegonia (4) flagellate spermatozoids In Chlorophyceae, sexual reproduction occurs by (1) isogamy and anisogamy (2) isogamy, anisogamy and oogamy (3) oogamy only (4) anisogamy and oogamy Cycas have two cotyledons but not included in angiosperms because of (1) naked ovules (2) tap root (3) circinate ptyxis (4) compound leaves

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Which of the following is the correct option ?

A

B

C

D

(1)

Porphyra

Fucus

Dictyota

Polysiphonia

(2) (3)

Polysiphonia Fucus

Porphyra Dictyota

Dictyota Porphyra

Fucus Polysiphonia

(4)

Porphyra

Polysiphonia

Fucus

Dictyota

PLANT KINGDOM 11.

12.

13. 14.

19.

93

What is true about male and female gametophyte in plant kingdom ? (1) In bryophytes and pteridophytes they have independent free-living existence. (2) In gymnosperms and angiosperms they have no independent free-living existence. (3) Both 1 and 2 (4) In bryophytes, pteridophytes and angiosperms they have free-living life. They remain in sporangia which are retained on sporophytes. An important difference between the zoospores and aplanospores is that (1) zoospores are uninucleate while aplanospores are binucleate (2) zoospores are large while aplanospores are smaller (3) zoospores are motile while aplanospores are nonmotile (4) None of the above The endosperm of gymnosperm is (1) haploid (2) diploid (3) triploid (4) tetraploid When pollen of a flower is transferred to the stigma of another flower of the same plant, this pollination is referred to as (1) xenogamy (2) geitonogamy (3) autogamy (4) allogamy

15.

16.

17.

18.

When pollen tube enters through funiculus or integument, it is called ? (1) porogamy (2) chalazogamy (3) cesogamy (4) isogamy Reinder moss is the common name of (1) Usnea comosa (2) Cladonia rangifera (3) Funaria hygrometrica (4) Sphagnum aceutifolium Which of the following correctly explains why rhodophyta exhibit a red colour ? (1) Since most rhodophyta grow at great depths, the chlorophyll can only absorb light in the red area of the spectrum. (2) The wavelengths of light that are absorbed by chlorophyll are passed to phycoerythrin (a red pigment). (3) Phycoerythrin absorbs all the light waves. (4) Light reaching the greatest depth in water is in the bluegreen region of the spectrum. This light is absorbed by phycoerythrin. Red snow causing alga is (1) Chlamydomonas nivalis (2) Chlamydomonas reinhardtii (3) Chlamydomonas debaryanum (4) Chalmydomonas media

Choose the right option.

(1) (2) (3) (4)

A

B

C

D

Volvox Chara Laminaria Chlamydomonas

Chlamydomonas Laminaria Volvox Chara

Laminaria Volvox Chlamydomonas Laminaria

Chara Chlamydomonas Chara Volvox

94 20.

BIOLOGY Which is the right option ?

(1) (2) (3) (4) 21.

A

B

C

D

Gemma cup Archegoniophore Archegonia Antheridia

Archegoniophore Gemma cup Antheridia Archegonia

Sporophyte Gametophyte Gemma cup Gemma cup

Sphagnum Sphagnum Sphagnum Sphagnum

Identify the dicot and monocot characters respectively.

(1) A, C, F, H; and B, D, E, G (3) A, C, E, G; and B, D, F, H 22.

(2) (4)

A, D, F, H; and B, C, E, G B, C, F, H; and A, D, E, G

Consider the following four statements (I) The sporophyte in liverworts is more elaborate than that in mosses (II) Salvinia is heterosporous (III) The life-cycle in all seed-bearing plants is diplontic (IV) In Pinus male and female cones are borne on different trees Which two statements out of four are wrong ? (1) Statements (I) and (III) (2) Statements (I) and (IV) (3) Statements (II) and (III) (4) Statements (I) and (II)

23.

Which one of the following is the major difference between mosses and ferns ? (1) Ferns lack alternation of generation while mosses show the same. (2) Mosses are facultative aerobes while ferns are obligate aerobes. (3) Vascular bundles of ferns show xylem vessels while those of mosses lack it. (4) Sporophytes of ferns live much longer as compared to the sporophytes of mosses.

PLANT KINGDOM 24.

95

Identify the plants which are given below and choose the correct option.

(1) (2) (3) (4) 25.

A

B

C

D

Equisetum Selaginella Funaria Chara

Ginkgo Equisetum Adiantum Marchantia

Selaginella Salvinia Salvinia Fucus

Lycopodium Ginkgo Riccia Pinus

What structures A and B respectively indicate in the life cycle of bryophytes, pteridophytes and gymnosperms? Mitosis Zygote (2n)

Sporophyte (multicellular diploid, 2n)

Meiosis

Fertilization Gametes (n)

Haploidspores (n) Mitosis

(1) (2) (3) (4)

A Bryophytes Pteridophytes Gymnosperms Bryophytes Pteridophytes Gymnosperms Bryophytes Pteridophytes Gymnosperms Bryophytes Peteridophytes Gymnosperms

ANSWER KEY

Gemetophyte (multicellular haploid, n)

: : : : : : : : : : : :

Mitosis

B sporangium, capsule strobili, sporangia flowers, cones capsule, protonema (gametophores) sporangia, cones, sporophyll fertile fronds, megasporangia and microsporangia protonema, gametophores strobili, sporangia flowers, cones strobili, capsule cones, sporangia flowers, cones

96 26.

BIOLOGY Which one of the following option correctly represents the type of life cycle patterns? Sporophyte (2n)

Zygote (2n)

Meiosis

Syngamy Zygote (2n)

A

B Gametogenesis

Sporophyte (2n) Zygote (2n) Syngamy

Spores (n)

Gametogenesis

Meiosis

C

Gametogenesis

Spores (n)

Syngamy Meiosis

Gametophyte (n)

Gametophyte (n)

(n)

27.

(1) A - Diplontic, B - Haplodiplontic, C - Haplontic (2) A - Haplodiplontic,B - Haplontic, C - Diplontic (3) A - Haplontic, B - Diplontic, C - Haplodiplontic (4) A - Diplontic, B - Haplontic, C - Haplodiplontic Life cycle of an angiosperm is given below. A, B, C, D and E are respectively. B A Microspore mother cells Filament

Style

Microsporangium Ovary Flower

Microspores

Megaspore mother cell

Megasporangium (ovule) Sporophyte

GAMETOPHYTIC (n) GENERATION

SPOROPHYTIC (2n) GENERATION

Microspore (pollen grain) Embryo E Zygote

D

C Male gametes

(1) A–Stigma, B–Anther, C–Male gametophyte, D–Egg, E–Female gametophyte (2) A–Stigma, B–Anther, C–Female gametophyte, D–Egg, E–Male gametophyte (3) A–Stigma, B–Anther, C–Male gametophyte, D–Fertilized egg, E–Female gametophyte (4) A–Stigma, B–Anther, C–Embryo sac, D–Egg, E–Female gametophyte 28.

Which is the correct combination ? Column-I

Column-II

(A) Agar

(I)

Single cell protein, use as food supplements by space travellers

(B) Algin

(II) Red algae

(C) Carrageen

(III) Brown algae

(D) Chlorella and Spirullina (IV) Gelidium,Gracilaria (1) A → I; B → II; C → III; D → IV

(2)

A → IV; B → III; C → II; D → I

(3) A → II; B → I; C → III; D → IV

(4)

A → III; B → II; C → I; D → IV

PLANT KINGDOM 29.

97

Match the following Column-I

Column-II

(Classes)

(Examples)

(A) Psilotopsida

(I)

Dryopteris, Pteris, Adiantum

(B) Lycopsida

(II) Equisetum

(C) Sphenopsida

(III) Selaginella

(D) Pteropsida

(IV) Lycopodium (V) Psilotum

(1) A → V; B → III; C → II; D → I (2) A → I; B → II; C → III; D → IV (3) A → IV; B → III; C → II; D → I (4) A → III; IV; B → V; C → I; D → II 30.

Column-I

Column-II

((A) Haplontic life cycle

(I) Bryophytes, Pteridophytes, Ectocarpus, Polysiphonia, kelps

(B) Diplontic life cycle

(II) Seed bearing plants (Gymnosperm and Angiosperm), Fucus

(C) Haplo-diplontic life cycle (III) Many algae (Volvox, Spyrogyra, and some species of Chlamydomonas) Which is the correct combination ? (1) A → III; B → II; C → I (2) A → I; B → II; C → III (3) A → II; B → I; C → III (4) A → III; B → I; C → II 31.

Which one of the following is the correct about Pinus ? (1) Monoecious – Male (microsporangiate) and female (megasporangiate) cones are produced on same plant. (2) Monoecious – Male and female sporophylls borne on same strobilus. (3) Dioecious – Male and female cones are produced on different plants. (4) Monoecious – Micro and megasporocarp develop on same plant.

98

BIOLOGY

EXERCISE - 2 | Window to Competitive Exams 1.

The absence of chlorophyll, in the lowermost cell of Ulothrix, shows [CBSE'95]

10.

(1) functional fission

(1) water is essential for fertilization for their homosporous nature.

(2) tissue formation

(2) water is essential for their vegetative propagation.

(3) cell characteristic

(3) the sperms can easily reach upto egg in the archegonium.

(4) beginning of labour division 2.

3.

Agar is commercially obtained from (1) red algae

(2) green algae

(3) brown algae

(4) blue-green algae

The plant body of moss (Funaria) is

(4) archegonium has to remain filled with water for fertilization.

[CBSE'95] 11.

(2) completely gametophyte

A well developed archegonium with neck consisting of 4-6 rows of neck canal cells, is a characteristic of

12.

(2) bryophytes and pteridophytes (3) pteridophytes and gymnosperms (4) gymnosperms and angiosperms 5.

Which one of the following have elaters with mature spores in the capsule? [CBSE'96] (1) Riccia

6.

7.

8.

13.

(2) Marchantia

(3) Funaria (4) Sphagnum Seed-habit first originated in [CBSE'96] (1) certain ferns (2) certain pines (3) certain monocots (4) primitive dicots Multicellular branched rhizoids and leafy gametophytes are characteristic of [CBSE'97]

14.

(1) all bryophytes

(2) some bryophytes

15.

(3) all pteridophytes

(4) some pteriodphytes

Bryophytes can be separated from algae because they [CBSE'97] 16.

(1) are thalloid forms

non-motile colonial alga lacking zoospores

(3) membranous alga producing zoospores

[CBSE'95]

(1) gymnosperms only

(4) filamentous alga with flagellated reproductive stages The “walking” fern is so named because [CBSE'98] (1) it is dispersed through the agency of walking animals (2) it propagates vegetatively by its leaf tips (3) it knows how to walk by itself (4) its spores are able to walk A water fern which is used as a green manure in rice fields is [AMU'98] (1) Salvinia (2) Mucor (3) Aspergillus (4) Azolla Which one of the following statements about Cycas is incorrect? [CBSE'98] (1) It does not have a well-organized female flower (2) It has circinate vernation (3) Its xylem is mainly composed of xylem vessels (4) Its roots contain some blue-green algae. Largest sperms in the plant world are found in [CBSE'98] (1) Pinus (2) Banyan (3) Cycas (4) Thuja Brown algae is characterised by the presence of [CBSE'99]

(2) have no conducting tissue (1) phycocyanin

(3) possess archegonia with outer layer of sterile cells (4) contain chloroplasts in their cells 9.

[CBSE'97]

An alga rich in protein is (1) Spirogyra

(2) Ulothrix

(3) Oscillatoria

(4) Chlorella

[CBSE'98]

(2) filamentous alga lacking flagellated reproductive stages

(3) predominantly sporophyte with gametophyte (4) predominantly gametophyte with sporophyte

Ulothrix can be described as a (1)

[CBSE'95]

(1) completely sporophyte

4.

Bryophytes are dependent on water because [CBSE'98]

17.

(2) phycoerythrin

(3) fucoxanthin (4) carragean The antherozoids of Funaria are (1) aciliated

(2) flagellated

(3) multiciliated

(4) monociliated

[CBSE'99]

PLANT KINGDOM 18.

19.

20.

21.

22.

23.

24.

25.

26.

27.

28.

29.

Bryophytes comprise [CBSE'99] (1) sporophyte of longer duration (2) dominant phase of sporophyte which is parasitic (3) dominant phase of gametophyte which produces spores (4) small sporophyte phase and generally parasitic on gametophyte. Which of the following is true about bryophytes? [CBSE'99] (1) They possess archegonia. (2) They contain chloroplast. (3) They are thalloid. (4) All of these Columella is a specialised structure found in the sporangium of [CBSE'99] (1) Ulothrix (2) Rhizopus (3) Spirogyra (4) None of these Dichotomous branching is found in [CBSE'99] (1) fern (2) Funaria (3) liverworts (4) Marchantia The heart shaped fern prothallus is [AIIMS'99] (1) gametophyte (2) sporophyte (3) embryo (4) gamete “Chilgoza”, a gymnosperm seed, that is eaten as a “dry fruit” is produced by [AMU'99] (1) Pinus roxburghii (2) Pinus gerardiana (3) Ginkgo biloba (4) Cedrus deodara Gymnosperms lack fruit, because they lack (1) ovule (2) ovary [AFMC'99] (3) embryo (4) seed Which of the following is a “resurrection” plant ? [AFMC'99] (1) Lycopodium (2) Selaginella (3) Rhynia (4) Marsilea Floridean starch is found in [CBSE'2000] (1) chlorophyceae (2) rhodophyceae (3) myxophyceae (4) cyanophyceae A research student collected certain alga and found that its cells contained both chlorophyll a and chlorophyll b as well as phycoerythrin.The alga belongs to [CBSE'2000] (1) rhodophyceae (2) bacillariophyceae (3) chlorophyceae (4) phaeophyceae Laminaria (kelp) and Fucus (rock weed) are the examples of [AFMC'2000] (1) red algae (2) brown algae (3) green algae (4) golden brown algae Floridean starch is found in [BHU'2000] (1) chlorophyceae (2) myxophyceae (3) phaeophyceae (4) rhodophyceae

99 30.

31.

32.

Like angiospermic parasite such as Cuscuta, there are some parasitic forms of rhodophyta, which are colourless, heterotrophic and grow on other members of rhodophyta. Select which one is a parasitic form of red algae: [AMU'2000] (1) Gelidium (2) Harveyella (3) Choridras (4) Both (1) and (2) In the vast marine ecosystem, certain sea develop red colouration. This red colour is due to the presence of large population of which one of the following organisms? (1) Trichodesmium erythrium [AMU'2000] (2) Physarium (3) Dinoflagellates (4) Diatoms and members of red algae Number of cotyledons in Zea mays, Cycas and Pinus respectively are : [BHU'2000] (1) 1, 2, 4

33.

34.

35.

36.

37.

38.

(2) 1, 2, many

(3) 2, 2, many (4) 2, 1, 4 Which one of the following oils is produced by Linum usitatissimum in India ? [AFMC'2000] (1) Linseed oil (2) Sunflower oil (3) Groundnut oil (4) Palm oil One of the most important reasons why wild plants should thrive is that they are good sources of [CBSE'2000] (1) highly nutritive animal feed (2) unsaturated edible oils (3) genes for resistance to disease and pests (4) medicines 13 celled male gametophyte of Selaginella has [AIIMS'2000] (1) 12 cells of antheridium + 1 prothallial cell (2) 10 cells of antheridium + 3 prothallial cells (3) 9 cells of antheridium + 4 prothallial cells (4) 8 cells of antheridium + 6 prothallial cells Which of the following is found in algal zone of Cycas coralloid roots? [AIIMS'2000] (1) Blue green algae (2) Red algae (3) Green algae (4) Brown algae The largest ovules, largest male and female gametes and largest plants are found among [CBSE'2000] (1) angiosperms (2) tree ferns and some monocots (3) gymnosperms (4) dicotyledonous plants Which of the following is absent in the primary and secondary structure of stem of Pinus ? [AFMC'2000] (1) Sieve tubes (2) Mucilage duct (3) Companion cells (4) Phloem parenchyma

100 39.

40.

41.

42.

43.

44.

45.

46.

47.

48.

49.

50.

BIOLOGY In Ferns, meiosis occurs when [CBSE'2000] (1) spore germinates (2) gametes are formed (3) spores are formed (4) antheridia and archegonia are formed Spirogyra filaments increase in length due to division in [AFMC'01] (1) basal cells (2) middle cells (3) rhizoidal cells (4) all green cells Sex organs in Funaria develop [AIIMS'01] (1) in protonema (2) outside capsule (3) in the axil of leaf (4) at the tip of gametophore “Algal zone” is found in [AMU'01] (1) normal roots of Cycas (2) normal roots of Pinus (3) coralloid roots of Cycas (4) stem of Cycas Cycas and Ginkgo are regarded as primitive gymnosperms because [AMU'01] (1) they are lacking cones (2) they need water for fertilization (3) they are living fossils (4) they have ciliated sperms The tallest plant is [AMU'01] (1) Sequoia (2) Eucalyptus (3) Pinus (4) Casuarina Cycas is [AIIMS'01] (1) monoecious (2) bisexual (3) dioecious (4) hermaphrodite Algae are useful because they [AIIMS'02] (1) purify the atmosphere (2) are large in number (3) are used in fermentation (4) are used to study respiration Which of the following is a important characteristic of angiosperms? [CBSE'02] (1) presence of vessels (2) double fertilisation (3) secondary growth (4) autotrophic nutrition The nature of megasporophyll of Cycas is similar to [AIIMS'02] (1) stamen (2) carpel (3) sepal (4) petal Which of the following plants produces seeds but not flowers? [CBSE'02] (1) Maize (2) Mint (3) Peepal (4) Pinus Sexual reproduction in Spirogyra is an advanced feature because it shows [CBSE'03]

51.

52.

53.

54.

55.

56.

57.

58.

59.

60.

(1) physiologically differentiated sex organs (2) different sizes of motile sex organs (3) same size of motile sex organs (4) morphologically different sex organs Which one of the following pairs of plants are not seed producers? [CBSE'03] (1) Funaria and Pinus (2) Fern and Funaria (3) Funaria and Ficus (4) Ficus and Chlamydomonas People recovering from long illness are often advised to include the alga Spirulina in their diet because it [AIIMS'03] (1) makes the food easy to digest. (2) is rich in proteins. (3) has antibiotic properties. (4) restores the intestinal microflora. Algae used in space programme is [BHU'03] (1) diatom (2) dinoflagellates (3) Chlamydomonas (4) Chlorella Funaria gametophyte is [AMU'03] (1) dioecious (2) heteroecious (3) autoecious (4) monoecious and autoecious In Funaria the haploid structure is [AMU'03] (1) protonema (2) capsule (3) columella (4) seta Which of the following is an fatty oil yielding plant? [AFMC'03] (1) Sunflower (2) Acacia (3) Butea (4) Casuarina Which one pair of examples will correctly represent the spermatophyta according to one of the schemes of classifying plants ? [CBSE'03] (1) Ginkgo, Pisum (2) Acacia, Sugarcane (3) Pinus, Cycas (4) Rhizopus, Triticum Which one of the following is a living fossil? [CBSE'96,97,03] (1) Pinus (2) Opuntia (3) Ginkgo (4) Thuja Sea weeds are important source of [AFMC'04] (1) chlorine (2) fluorine (3) iodine (4) thiamine Which of the phanerogams? (1) angiosperms (2) gymnosperms (3) pteridophytes (4) both (1) & (2)

following

is/are

grouped under [BHU'04]

PLANT KINGDOM 61.

62.

63.

64.

65.

66.

67.

68.

Tallest angiosperm is [AFMC'04] (1) Eucalyptus (2) red wood tree (3) oak tree (4) Pinus Dispersal of spores in fern takes place through [AFMC'05] (1) annulus (2) stomium (3) both (1) and (2) (4) indusium Which of the following is not the feature of gymnosperms ? [BHU'05] (1) Parallel venation (2) Perennial plants (3) Distinct branches (long and short branches) (4) Xylem with vessels Match items in Column I with those in Column II : Column -I Column -II (I) Peritrichous (J) Ginkgo flagellation (II) Living fossil (K) Macrocystis (III) Rhizophore (L) Escherichia coli (IV) Smallest (M) Selaginella flowering plant (V) Largest perennial (N) Wolffia alga Select the correct answer from the following: (1) I-L; II-J; III-M; IV-N; V-K; [CBSE'05] (2) I-K; II-J; III-L; IV-M; V-N (3) I-N; II-L; III-K; IV-N; V-J; (4) I-J; II-K; III-N; IV-L; V-K In moss the sporophyte [CBSE'06] (1) produces gametes that give rise to the gametophyte (2) arises from a spore produced from the gametophyte (3) manufactures food for itself as well as for the gametophyte (4) is partially parasitic on the gametophyte Conifers differ from grasses in the [CBSE'06] (1) lack of xylem tracheids (2) absence of pollen tubes (3) formation of endosperm before fertilization (4) production of seeds from ovules Which one of the following groups of genera are pollinated by the same agency? [AIIMS'06] (1) Triticum, Cocos, Mangifera (2) Ficus, Kigelia, Casuarina (3) Salvia, Morus, Euphorbia (4) Bombax, Butea, Bauhinia In the prothallus of a vascular cryptogam, the antherozoids and eggs mature at different times. As a result [CBSE'07] (1) there is high degree of sterility (2) one can conclude that the plant is apomictic (3) self-fertilization is prevented (4) there is no change in success rate of fertilization

101 69.

70.

71.

72.

73.

74.

75.

76.

77.

Spore dissemination in some liverworts is aided by [CBSE'07] (1) indusium (2) calyptra (3) peristome teeth (4) elaters Flagellated male gametes are present in [CBSE'07] (1) Zygnema, Pinus and Hydrilla (2) Fucus, Marsilea and Calotropis (3) Riccia, Dryopteris and Cycas (4) Anthoceros, Funaria and Spirogyra In gymnosperms, the pollen chamber represents [CBSE'07] (1) a cavity in the ovule in which pollen grains are stored after pollination (2) an opening in the megagametophyte through which the pollen tube approaches the egg (3) the microsporangium in which pollen grains develop (4) a cell of the pollen grain in which the sperms are formed. In which one of the following, male and female gametophytes do not have free living independent existence? [CBSE'08] (1) Pteris (2) Funaria (3) Polytrichum (4) Cedrus Which one of the following is heterosporous ? [CBSE'08] (1) Dryopteris (2) Salvinia (3) embryo (4) Equisetum Select one of the following pairs of important features distinguishing Gnetum from Cycas and Pinus and showing affinities with angiosperms [CBSE'08] (1) absence of resin duct and leaf venation (2) presence of vessel elements and absence of archegonia (3) perianth and two integuments (4) embryo development and apical meristem Which one of the following plants is monoecious? [CBSE'09] (1) Pinus (2) Cycas (3) Papaya (4) Marchantia Which one of the following has haplontic life cycle? [CBSE'09] (1) Polytrichum (2) Ustilago (3) Spirogyra (4) Funaria Some hyperthermophilic organisms that grow in highly acidic (pH=2) habitats belong to [CBSE'10] (1) eubacteria and archaea (2) cyanobacteria and diatoms (3) protists and mosses (4) liverworts and yeasts

102 78.

79.

80.

81.

82.

83.

84.

85.

BIOLOGY Algae have cell wall made up of [CBSE'10] (1) cellulose, galactans and mannans (2) hemicellulose, pectins and proteins (3) pectins, cellulose and proteins (4) cellulose, hemicellulose and pectins. Male and female gametophytes are independent and free -living in: [CBSE PMT 2010] (a) Mustard (b) Castor (c) Pinus (d) Sphagnum Algae have cell wall made up of: [CBSE PMT 2010] (a) cellulose, galactans and mannans (b) hemicellulose, pectins and proteins (c) pectins, cellulose and proteins (d) cellulose, hemicellulose and pectins Some hyperthermophilic organisms that grow in highly acidic (pH2) habitats belong to the two groups: [CBSE PMT 2010] (a) Eubacteria and archaea (b) Cyanobacteria and diatoms (c) Protists and mosses (d) Liverworts and yeasts In the diagram given above, some of the algae have been labelled as ‘A’, ‘B’, ‘C’, ‘D’ and ‘E’. These algae are respectively identified as : [Kerala PMT 2010] (a) Dictyota, Polysiphonia, Porphyra, Fucus and Laminaria (b) Porphyra, Dictyota, Laminaria, Fucus, and Polysiphonia (c) Dictyota, Polysiphonia, Porphyra, Laminaria and Fucus (d) Fucus, Porphyra, Dictyota, Polysiphonia, and Laminaria Identify the alga which exhibits diplontic life cycle. [Kerala PMT 2010] (a) Spirogyra (b) Chlamydomonas (c) Fucus (d) Volvox Which of the following pteridophytes is heterosporous in nature? [Kerala PMT 2010] (a) Psilotum (b) Adiantum (c) Equisetum (d) Salvinia Consider the following statements regarding gymnosperms and choose the correct option. (A) In gymnosperms, the male and female gametophytzes have an independent existence (B) The multicellular female gametophyte is retained within the megasporangium (C) The gymnosperms are heterosporous Of these statements [Kerala PMT 2010] (a) (A) and (B) are true but (C) is false

86.

87.

88.

89.

90.

91.

92.

93.

(b) (A) and (C) are true but (B) is false (c) (B) and (C) are false but (A) is true (d) (B) and (C) are true but (A) is false Pick out wrong statement: [Kerala PMT 2010] (a) double fertilization is unique to gymnosperms and monocotyledons (b) Sequoia, a gymnosperm, is one of the tallest trees (c) phaeophyceae members possess chlorophyll a, c, carotenoids and xanthophylls (d) moss is a gametophyte which consists of two stages namely, protonema stage and leafy stage In angiosperms, functional megaspore develops into [CBSE'11] (1) embryo sac (2) ovule (3) endosperm (4) pollen sac Select the correct match from the options given below. [Kerala PMT 2011] (A) Phaeophyceae Mannitol (B) Rhodophyceae Dictyota (C) Chlorophyceae Non-motile gametes (D) Rhodophyceae r-Phycoerythrin (a) A, B & C (b) B, C & D (c) A & C (d) C & D In angiosperms, functional megaspore develops into [CBSE PMT 2011M] (a) embryo sac (b) ovule (c) endosperm (d) pollen sac Heterocysts are present in [JIPMER-2011] (a) Riccia (b) Ulothrix (c) Albugo (d) Nostoc In gymnosperms, the pollen chamber represents [JIPMER-2011] (a) a cell in the pollen grain in which the sperms are formed (b) a cavity in the ovule in which pollen grains are stored after pollination (c) an opening in the mega gametophyte through which the pollen tube approaches the egg (d) the microsporangium in which pollen grains develop Which of the following Pteridophytes belong to class Pteropsida? [Kerala PMT 2011] (a) Equisetum and Psilotum (b) Lycopodium and Adiantum (c) Selaginella and Pteris (d) Pteris and Adiantum Cycas and Adiantum resemble each other in having: [CBSE PMT 2012] (a) Seeds (b) Motile Sperms (c) Cambium (d) Vessels

PLANT KINGDOM

103

94.

Which one of the following is a correct statement? [CBSE PMT 2012] (a) Pteridophyte gametophyte has a protonemal and leafy stage (b) In gymnosperms female gametophyte is free-living (c) Antheridiophores and archegoniophores are present in pteridophytes. (d) Origin of seed habit can be traced in pteridophytes 95. Which one of the following is common to multicellular fungi, filamentous algae and protonema of mosses [CBSE PMT 2012] (a) Diplontic life cycle (b) Members of kingdom plantae (c) Mode of Nutrition (d) Multiplication by fragmentation 96. Read the following five statements (A - E) and answer the question. [CBSE PMT 2012M] (A) In Equisetum the female gametophyte is retained on the parent sporophyte. (B) In Ginkgo male gametophyte is not independent. (C) The sporophyte in Riccia is more developed than that in Polytrichum. (D) Sexual reproduction in Volvox is isogamous. (a) Two (b) Three (c) Four (d) One 97. Which one of the following pairs is wrongly matched? [CBSE PMT 2012M] (a) Ginkgo -Archegonia (b) Salvinia - Prothallus (c) Viroids - RNA (d) Mustard - Synergids 98. Sporocarp is a reproductive structure of [AIIMS 2012] (a) Some algae (b) Some aquatic ferns having sori (c) Angiosperms having spores (d) Bryophytes 99. The heterosporous pteridophyte belonging to the class lycopsida is [Kerala PMT 2012] (a) Selaginella (b) Psilotum (c) Equisetum (d) Pteris 100. Consider the following statements with respect to algae. [Kerala PMT 2012] A. Fusion between one large, non-motile female, gamete and a smaller, motile male gamete is termed as oogamous. B. Fusion of two gametes dissimilar in size is termed as oogamous. C. Fusion of two gametes similar in size is called anisogamous. D. In chlorophyceae the major pigments are chlorophyll a and b , and the food is stored as starch.

E.

101.

102.

103.

104.

105.

106.

107.

In rhodophyceae the major pigments are chlorophyll a and d , and the food is stored as mannitol. Of the above statements (a) A and E alone are correct (b) C and E alone are correct (c) A and B alone are correct (d) A and D alone are correct Consider the following statements with respect to gymnosperms and angiosperms. [Kerala PMT 2012] A. Double fertilization is an event unique to gymnosperms. B. Angiosperms range in size from microscopic Wolffia to tall trees of Sequoia. C. In gymnosperms the seeds are not covered. D. In gymnosperms the male and female gametophytes have an independent free living existence. Of the above statements (a) A and B alone are correct (b) C alone is correct (c) B and C alone are correct (d) C and D alone are correct Choose the correct order of colours with respect of pigments, chlorophyll, phycoerythrin and fucoxanthin. [Kerala PMT 2012] (a) Green, red and brown (b) Brown, green and red (c) Red, green and brown (d) Green, brown and red (e) Brown, red and green The green alga rich in proteins used as food supplements even by space travellers is [Kerala PMT 2012] (a) Chlamydomonas (b) Volvox (c) Spirogyra (d) Chlorella Which of the following is a phaeophycean alga? [Kerala PMT 2012] (a) Gelidium (b) Polysiphonia (c) Porphyra (d) Laminaria Which of the following is a character of rhodophyceae? [Kerala PMT 2012] (a) Major pigments are chlorophyll-a and chlorophyll-b. (b) Commonly called brown algae. (c) Stored food materials are mannitol and laminarin. (d) Flagellum is absent. The amphibians of the plant kingdom are [Kerala PMT 2012] (a) gymnosperms (b) bryophytes (c) pteridophytes (d) fungi (e) algae Which one of the following is a saprophytic bryophyte? [JIPMER-2012] (a) Riccia fluitans (b) Buxbaumia aphylla (c) Funaria hygrometrica (d) Sphagnum

104

BIOLOGY

108. Iodine is obtained from

[JIPMER-2012]

(a) Laminaria

(b) Chlorella

(c) Polysiphonia

(d) Porphyra

109. Which of the following is called amphibians of plant kingdom? [AFMC 2012] (a) Bryophytes

(b) Pteridophytes

(c) Gymnosperms

(d) Algae

110. Which of these is not a character of Bryophytes? [Kerala PMT 2013] (a) The main plant body is haploid. (b) They possess multicellular sex organs. (c) They need water for sexual reproduction. (d) They colonise rocks and are of great ecological significance. 111. I. II.

In Rhodophyceae, food is stored in the form of mannitol and laminarin. The ovules of Gymnosperms are not enclosed by ovary wall.

III. Salvinia is heterosporous. IV. In the diplontic life-cycle, the free living gametophyte represents the dominant phase. Of the above statements

[Kerala PMT 2013]

(a) II and III are correct but I and IV are wrong. (b) II and IV are correct but I and III are wrong. (c) III and IV are correct but I and II are wrong. (d) I and II are correct but III and IV are wrong. 112. The diagram represents the life cycle pattern of an angiosperm. Choose the correct combination of labelling numbered as 1 to 5. [Kerala PMT 2013]

(a) (b) (c) (d) (e)

1. Anther 2. Ovary 3. Microspore 4. Zygote 5. Embryo 1. Embryo 2. Zygote 3. Anther 4. Ovary 5. Microspore 1. Ovary 2. Anther 3. Microspore 4. Zygote 5. Embryo 1. Anther 2. Ovary 3. Zygote 4. Embryo 5. Microspore 1. Zygote 2. Embryo 3. Anther 4. Ovary 5. Microspore

113. Besides paddy fields cyanobacteria are also found inside vegetative part of : [AIPMT (NEET) 2013] (a) Cycas (b) Equisetum (c) Psilotum (d) Pinus 114. Isogamous condition with non-flagellated gametes is found in : [AIPMT (NEET) 2013] (a) Spirogyra (b) Volvox (c) Fucus (d) Chlamydomonas 115. Read the following statements (A-E) and answer the question which follows them. [AIPMT (NEET) 2013] 1. In liverworts, mosses and ferns gametophytes are free-living 2. Gymnosperms and some ferns are heterosporous. 3. Sexual reproduction in Fucus, Volvox and Albugo is oogamous 4. The sporophyte in liveworts is more elaborate than that in mosses 5. Both, Pinus and Marchantia are dioecious How many of the above statements are correct? (a) Two (b) Three (c) Four (d) One 116. Which of the following is not correctly matched for the organism and its cell wall degrading enzyme? [AIPMT (NEET) 2013] (a) Plant cells-Cellulase (b) Algae-Methylase (c) Fungi-Chitinase (d) Bacteria-Lysozyme 117. Coralloid roots of Cycas is distinguished from angiosperm roots by [AIIMS 2013] (a) absence of pith (b) having xylem tissue (c) absence of algal zone (d) presence of algal zone 118. Which one of the following shows isogamy with nonflagellated gametes? [AIPMT 2014] (a) Sargassum (b) Ectocarpus (c) Ulothrix (d) Spirogyra 119. Which one of the following is wrong about Chara? [AIPMT 2014] (a) Upper oogonium and lower round antheridium. (b) Globule and nucule present on the same plant. (c) Upper antheridium and lower oogonium. (d) Globule is male reproductive structure. 120. Which of the following is responsible for peat formation? [AIPMT 2014] (a) Marchanita (b) Riccia (c) Funaria (d) Sphagnum 121. An alga which can be employed as food for human being is: [AIPMT 2014] (a) Ulothrix (b) Chlorella (c) Spirogyra (d) Polysiphonia

PLANT KINGDOM 122. In which of the ffollowing gametophyte is not independent free living ? [AIPMT 2015] (a) Marchantia (b) Pteris (c) Pinus (d) Funaria 123. Read the following five statements (A to E) and select the option with all correct statements : [AIPMT 2015] (A) Mosses and Lichens are the first organisms to colonise a bare rock. (B) Selaginella is a homosporous pteridophyte (C) Coralloid roots in Cycas have VAM (D) Main plant body in bryophytes is gametophytic, whereas in pteridophytes it is sporophytic (E) In gymnosperms, male and female gametophytes are present within sporangia located on sporophyte

105 (a) (B), (C) and (D) (b) (A), (D) and (E) (c) (B), (C) and (E) (d) (A), (C) and (D) 124. Male gemetes are flagellated in : [AIPMT 2015] (a) Anabaena (b) Ectocarpus (c) Spirogyra (d) Polysiphonia 125. Which one of the following statements is wrong? [AIPMT 2015] (a) Agar - agar is obtained from Gelidium and Gracilaria (b) Chlorella and Spirulina are used as space food (c) Mannitol is stored food in Rhodophyceae (d) Algin and carragen are products of algae

106

BIOLOGY

EXERCISE - 3 | Test Yourself 1.

2.

3.

4.

5.

6.

Phycology is the study of

9.

(1) algae

(2) fungi

Which one of the following is not a character of brown algae?

(3) bacteria

(4) all the above

(1) Presence of chlorophyll a & b

Group of algae in which sexual reproduction is absent

(2) It remains attached to substratum

(1) cyanophyceae

(2) bacillariophyceae

(3) Presence of chlorophyll a and c

(3) chlorophyceae

(4) None of these

(4) Presence of fucoxanthin

Mannitol is the stored food in (1) Chara

(2) Porphyra

(3) Fucus

(4) Gracillaria

10.

(1) Most algae are photosynthetic.

Red tide is caused by (1) Noctiluca

(2) Gymnodinium

(3) Gonyaulax

(4) All of these

Iodine is obtained from the members of (1) green algae

(2) brown algae

(3) red algae

(4) blue-green algae

(2) Algae can be classified according to their pigments. (3) All algae are filamentous. (4) Spirogyra does not produce zoospores. 11.

(1) They both respire and release CO2.

(A) In chlorophyceae the stored food material is starch and the major pigments are chlorophyll-a and d.

(3) They both reproduce asexually.

(2) They both are found in the same habitat.

(4) They both have same type of pigments. 12.

(C) In rhodophyceae, floridean starch is the stored food and the major pigments are chlorophyll-a, d and phycoerythrin. (1) A is correct, but B and C are wrong

13.

(2) A and B are correct, but C is wrong (3) A and C are correct, but B is wrong (4) C is correct, but A and B are wrong Which of the following genera belong to the same class of algae ?

14.

(1) Chara, Fucus, Polysiphonia (2) Volvox, Spirogyra, Chlamydomonas (3) Porphyra, Ectocarpus, Ulothrix (4) Sargassum, Laminaria, Gracilaria 8.

Which one of the following consider as the best evidence to show that two species of algae are closely related ?

Consider the following statements regarding the major pigments and stored food in the different groups of algae and choose the correct option

(B) In phaeophyceae, laminarin is the stored food and major pigments are chlorophyll-a and b.

7.

Which one of the following statements concerning the algae is wrong ?

External fertilization occurs in majority of (1) algae

(2) fungi

(3) liverworts

(4) mosses

15.

Algae are in the same group of plants as (1) mosses

(2) liverworts

(3) fungi

(4) ferns

Which of the following pigments is present in all algae? (1) Chlorophyll a

(2) Chlorophyll b

(3) Chlorophyll c

(4) Chlorophyll d

Sexual reproduction in algae results in the formation of (1) oospore

(2) zoospore

(3) zygote

(4) zygospore

Spirogyra has a (1) haplontic life cycle (2) diplontic life cycle (3) haplobiontic life cycle (4) diplobiontic life cycle

PLANT KINGDOM 16.

17.

18.

19.

20.

21.

107

Alginates (alginin), used as highly efficient gauze in internal operations are obtained from cell walls of

(3) Thallus like plant body, presence of root and autotrophic nutrition

(1) Cyanophyceae

(2) Phaeophyceae

(3) Rhodophyceae

(4) All of these

(4) Thallus like plant body, lack of vascular tissues and autotrophic nutrition

‘Diatomite’ is obtained from

28.

(1) Myxophyceae

(2) Bacillariophyceae

(1) ciliated sperms

(2) green colour

(3) Phaeophyceae

(4) Rhodophyceae

(3) protonema

(4) some are still aquatic

An important antibiotic of algal origin is (1) Griseofulvin

(2) Chlorellin

(3) Streptomycin

(4) All of these

29.

(3) Western Ghats

Which alga is used in biological research? (1) Acetabularia

(2) Chlorella

(3) Chara

(4) All of these

30.

‘Water bloom’ is generally caused by (1) green algae

(2) blue-green algae

(3) red algae

(4) brown algae

31.

26.

27.

(2) fungi

(3) bryophytes

(4) pteridophytes

Bryophytes having

(4) small sporophyte phase and generally parasitic on gametophyte 32.

(1) Motile sperms

A bryophyte suddenly started reproducing parthenogenetically. The number of chromosomes of the second generation compared to parent plant will be

(2) Presence of archegonium

(1) same

(2) one-half

(3) Water is essential for fertilization

(3) double

(4) triple

Which is not the characteristic feature of bryophyta ?

(4) Independent autotrophic sporophyte

25.

(1) algae

(3) dominant phase of gametophyte which produces spores

(3) great ecological importance

24.

Sporophyte dependent upon gametophyte is found in

(2) dominant phase of sporophyte which is parasitic

(2) no value at all

23.

(4) Eastern Ghats

(1) sporophyte having longer duration

Bryophytes have

(4) a lot of aesthetic value

Which place in India is called “The Golden Mine of Liverworts” ? (1) Eastern Himalayas (2) Western Himalayas

(1) great economic value

22.

The evidence for aquatic origin of bryophytes is

33.

Along the sea-coast which of the following is least likely to be found? (1) Brown algae

(2) Red algae

(3) Mosses

(4) All the above

34.

First land inhabiting plants are (1) angiosperms

(2) gymnosperms

(3) bryophytes

(4) pteridophytes

35.

In Funaria (moss) spore germinates to produce (1) protonema

(2) prothallus

(3) proembryo

(4) embryo

Mosses are indicator of (1) air pollution

(2) water pollution

(3) radiation pollution

(4) soil pollution

Which one of the following is heterosporous ?

Gametophytic generation is dominant in

(1) Adiantum

(2) Equisetum

(1) pteridophyta

(2) bryophyta

(3) Dryopteris

(4) Salvinia

(3) angiosperms

(4) gymnosperms

36.

Which one of the following is of considerable economic importance ? (1) Riccia

(2) Funaria

(3) Marchantia

(4) Sphagnum

Bryophytes resemble algae in the following aspects (1) Filamentous body, presence of vascular tissues and autotrophic nutrition (2) Differentiation of plant body into root, stem and leaves and autotrophic nutrition

Which statement is true ? (1) Spores and gametes are invariably diploids. (2) Spores and gametes are invariably haploids. (3) Only gametes are invariably haploids. (4) Only spores are invariably diploids.

37.

Which is the most important group on earth ? (1) Mosses

(2) Tracheophyta

(3) Bryophyta

(4) Liverworts

108 38.

39.

BIOLOGY 46.

“Botanical snakes” are (1) algae

(2) fungi

(1) biciliate and coiled

(3) bryophytes

(4) pteridophytes

(2) multiciliate and sickle-shaped

Heterosporous pteridophytes always produce

(3) multiflagellate and coiled

(1) monoecious gametophytes

(4) biciliate and sickle-shaped

(2) dioecious gametophytes

47.

(3) homothallic gametophytes (4) None of the above 40.

In pteridophytes, phloem is without

48.

(1) sieve cells (2) sieve tubes

49.

(3) companion cells

(2) has association with nitrogen-fixing Rhizobium (3) has association with nitrogen-fixing cyanobacteria

43.

44.

45.

(1) sporophyll

(2) frond

(3) leaf petiole

(4) leaf node

The shape of sporangium in fern is (1) biconvex

(2) circular

(3) biconcave

(4) plano-convex

In fern, sporangia are borne on the (2) abaxial side of leaf

Azolla is used as a biofertilizer because it

(3) adaxial side of leaf

(1) multiplies very fast to produce massive biomass

42.

New leaf of ferns is called

(1) margin of leaf

(4) Both (2) and (3) 41.

The sperm of fern is

(4) only on the tip of leaf 50.

Which of the following venation is characteristic of fern ?

(4) has association with mycorrhiza

(1) parallel

(2) reticulate

The gametophyte of fern bears

(3) dichotomous

(4) open furcate

(1) true roots

(2) Antheridia

(3) archegonia

(4) Both (2) and (3)

The first plants to appear after a forest fire are the ferns, this is because of the survival of their

51.

52.

In fern, spores are formed in (1) sporangium

(2) oogonium

(3) archegonium

(4) stomium

Physiological heterospory is seen in

(1) spores

(2) leaves

(1) Chlamydomonas

(2) Rhizopus

(3) fronds

(4) rhizomes

(3) Selaginella

(4) Lycopodium

The number of spores in the sporangium of fern is

53.

In gymnosperms, the ovule is naked because

(1) 16

(2) 32

(1) ovary wall is absent

(3) 64

(4) 128

(2) integuments are absent

Which one of the following is correct ?

(3) perianth is absent

(1) Protonema of moss and prothallus of Dryopteris are sporophytic.

(4) nucellus is absent

(2) Protonema of moss and prothallus of Dryopteris are gametophytic. (3) Moss protonema is sporophytic, Pteris prothallus is gametophytic but plant body of Pteris and Funaria are gametophytic. (4) Plant body of moss is gametophytic while Dryopteris is both gametophytic and sporophytic.

54.

55.

Gymnosperms do not have (1) trees

(2) shrubs

(3) lianas

(4) herbs

In gymnosperms pollination is exclusively by (1) animals

(2) wind

(3) water

(4) insects

PLANT KINGDOM 56.

109

What is the similarity between gymnosperms and angiosperms ?

64.

(1) Phloem of both have companian cells. (2) Endosperm is formed before fertilization in both.

57.

58.

65.

63.

(4) None of these

Which one of the following is mismatched ? Visible

(4) Both have leaves, stem and roots.

(2) Kryptos

–

Concealed

A typical gymnospermous plant has 8 chromosomes in leaf cells. What will be number of chromosomes in the cells of its gametophyte ?

(3) Gymno

–

Naked

(4) Bryo

–

Liverworts

(1) 16

(2) 8

(3) 4

(4) 24

Cycas resembles angiosperms in having

(4) ovules

62.

(3) Selaginella

–

66.

67.

(3) motile sperms

61.

(2) Funaria

(1) Phaneros

(2) vessels

60.

(1) Riccia

(3) Origin of ovule and seed is similar in both.

(1) circinate vernation in leaves

59.

In which of the following secondary growth takes place ?

Which of the following contain xylem vessel ?

68.

Clamp connections are found in (1) phycomycetes

(2) ascomycetes

(3) basidiomycetes

(3) deuteromycetes

Which one of the following is not commercially produced by yeast? (1) Enzyme

(2) Vitamin

(3) Hormone

(4) Riboflavin

Secondary mycelium of mushroom produces umbrella like structure called as

(1) Bryophyte

(2) Pteridophyta

(1) primary mycelium

(2) tertiary mycelium

(3) Both (1) and (2)

(4) Angiosperm

(3) pileus

(4) gills

69.

Which is not a monocot ?

Eutrophication is the result of

(1) Rose

(2) Orchids

(1) bryophyte

(2) algae and aquatic plants

(3) Palms

(4) Banana

(3) gymnosperm

(4) pteridophyte

Which of the following is / are grouped under phanerogams ?

70.

Identify the algae known for a biological activity called bioluminescence.

(1) Angiosperms

(2) Gymnosperms

(1) Spirogyra

(2) Chlorella

(3) Pteridophytes

(4) Both (1) and (2)

(3) Cyclotella

(4) Noctiluca

Tap roots are commonly found in (1) gymnosperms

(2) angiosperms

(3) dicots

(4) monocots

Which of the following is considered as more evolved ? (1) Dicot plant

(2) Monocot plant

(3) Data are incomplete (4) Both (1) and (2)

71.

Which of the following algae are suitable for human consumption? (1) Laminaria and Fucus (2) Gracilaria and Chondrus (3) Porphyra and Spirogyra (4) Rhodymania and Porphyra

110

BIOLOGY

ANSWER KEY 1. 6. 11. 16. 21. 26. 31.

EXERCISE 1 : NCERT BASED QUESTIONS (1) 2. (2) 3. (2) 4. (1) 5. (1) 7. (3) 8. (2) 9. (1) 10. (3) 12. (3) 13. (1) 14. (2) 15. (2) 17. (2) 18. (1) 19. (1) 20. (1) 22. (2) 23. (4) 24. (2) 25. (4) 27. (1) 28. (2) 29. (1) 30. (1)

(1) (1) (3) (2) (2) (1)

EXERCISE 2 : WINDOW TO COMPETITIVE EXAMS 1. 6. 11. 16. 21. 26. 31. 36. 41. 46. 51. 56. 61. 66. 71. 76. 81. 86. 91. 96. 101. 106. 111. 116. 121.

(4) (1) (4) (3) (4) (2) (1) (1) (4) (1) (2) (1) (1) (3) (3) (2) (1) (1) (4) (1) (2) (2) (1) (2) (2)

2. 7. 12. 17. 22. 27. 32. 37. 42. 47. 52. 57. 62. 67. 72. 77. 82. 87. 92. 97. 102. 107. 112. 117. 122.

(1) (2) (2) (2) (1) (1) (2) (3) (3) (2) (2) (1) (3) (3) (4) (1) (3) (1) (4) (1) (1) (2) (1) (4) (3)

3. 8. 13. 18. 23. 28. 33. 38. 43. 48. 53. 58. 63. 68. 73. 78. 83. 88. 93. 98. 103. 108. 113. 118. 123.

(4) (3) (4) (4) (2) (2) (1) (3) (3) (2) (4) (3) (4) (3) (2) (1) (3) (5) (2) (2) (5) (1) (1) (4) (2)

4. 9. 14. 19. 24. 29. 34. 39. 44. 49. 54. 59. 64. 69. 74. 79. 84. 89. 94. 99. 104. 109. 114. 119. 124.

(2) (4) (3) (4) (2) (4) (3) (3) (1) (4) (4) (3) (1) (4) (2) (4) (4) (1) (4) (1) (4) (1) (1) (3) (2)

5. 10. 15. 20. 25. 30. 35. 40. 45. 50. 55. 60. 65. 70. 75. 80. 85. 90. 95. 100. 105. 110. 115. 120. 125.

(2) (3) (3) (2) (2) (2) (1) (4) (3) (1) (1) (4) (4) (3) (1) (1) (5) (4) (4) (4) (4) (5) (2) (4) (3)

EXERCISE 3 : TEST YOURSELF 1. 5. 6. 11.

(1)

2.

(1)

3.

(3)

4.

(4)

(2) Kelps like Fucus and Laminaria (members of Phaeophyceae) are rich source of iodine. (4) 7. (2) 8. (1) 9. (1) 10. (3) (4)

12.

(3)

13. 14.

(1) (4)

15.

(1)

16. 21. 26.

(2) (3) (4)

27. 32.

(4) (1)

33.

(1)

38. 39. 44.

45. 49.

50. 51. 56. 61. 62. 63. 64. 65. 70.

Because algae and fungi are the members of thallophyta. Zygote secreting a thick wall which acts as perennating spore (zygospore) and helps in perennation, dispersal and multiplication. Life cycle of Spirogyra is haplontic as dominant phase in life cycle is haploid (n) and diploid phase is represented only by zygospore. 17. (2) 18. (2) 19. (4) 20. (2) 22. (4) 23. (3) 24. (3) 25. (2) Sphagnum is used as fuel. It has the capacity to retain water for long periods and as such used to cover the plant roots during transportation. 28. (1) 29. (2) 30. (3) 31. (4) The number of chromosomes of the second generation will be same because no reduction division take place. 34. (1) 35. (4) 36. (2) 37. (2)

(4) Botanical snake : The leaves of “Ophioglossum” pteridophyte is like hood of black snake cobra. (2) 40. (3) 41. (3) 42. (4) 43. (4) (3) The number of spores per sporangium are fixed in every species and 64 is the maximum number of spores in sporangium. (2) 46. (3) 47. (2) 48. (1) (1) Sporangia develop in groups called sori. Sori develop on the lower surface of leaves and leaflets, laterally or marginally. (4) (1) 52. (3) 53. (1) 54. (4) 55. (2) (4) 57. (3) 58. (4) 59. (4) 60. (1) (4) (3) In dicots tap roots and in monocots adventitious roots is present. (2) (4) Secondary growth takes place in angiosperms because cambium are present (except monocots). (4) 66. (3) 67. (3) 68. (3) 69. (2) (4) 71. (4)

Chapter

4

Animal Kingdom (Part-I & II) Part-I : Animal Kingdom While going through the chapter pay special attention to the following – Terms and definitions – 1. Parazoa 2. Paurometabola 3. Filter feeders 4. Pseudocoelomate 5. Metagenesis 6. Malacology 7. Hexapoda 8. Botryoidal Tissue 9. Entomology 10. Living fossil 11. Flame cell 12. Paedogenesis Common Names – 1. Hook worm 2. Jelly fish 3. Venus flower basket 4. Sea Mouse 5. Sea Hare 6. Portueguese Man of war 7. Ship worm 8. Cuttle fish 9. Aristotle Lantern 10. Sea anemone Infective stages – 1. Tetranucleated cyst 2. Embryonated egg 3. Sporozoite 4. Bladderworm larva 5. Metacercaria 6. Trophozoite Differences – 1. Bilateral and Biradial symmetry 2. Schizocoel and Enterocoel 3. Blind Sac and Cell aggregate body plan 4. Strobilization and Metamerism Larvae – 1. Trochophore 2. Tornaria 3. Planula 4. Amphiblastula 5. Rhabditiform 6. Miracidium 7. Glochidium 8. Nauplius Animal Kingdom covers about 35-phyla, of which 11 are considered to be major phyla. In major phyla, 10 are from Non-chordates and 1 from chordates. The 11-major phyla are 1.

Phylum Protozoa : single celled (solitary or colonial)Eukaryotes

2.

Phylum Porifera : Sponges

3.

Phylum Cnidaria : Jelly fishes and sea anemones

4.

Phylum Ctenophora* : Comb jellies

5.

Phylum Platyhelminthes : Flat warms

6.

Phylum Aschelminthes : Round worms or thread worms.

7.

Phylum Annelida : Segmented worms (Earthworm, Leech etc.)

(*As Ctenophora includes less than 100 species, it is generally considered as a Minor Phylum with Rotifera, Phoronida, Brachiopoda and Gastrotricha etc.).

At a Glance               

Grade of organization Body wall Body plan Coelom Protostomes and deuterostomes Anamniota and amniota Protozoa Porifera Cnidaria (coelenterata) Ctenophora Platyhelminthes Aschelminthes Annelida Arthropoda Mollusca

 Echinodermata  Hemichordata  Chordata  Cephalochordata       

Urochordata Vertebrata Pisces

Amphibia Reptilia Aves

Mammalia

112

BIOLOGY 8.

Phylum Arthropoda : Jointed legged-invertebrates

9. 10. 11.

Phylum Mollusca : Snails, bivalves, octopus etc. Phylum Echinodermata : Sea star, Brittle star, Sea lily etc. Phylum Chordata : Protochordates and vertebrates From 1 - 10 are Non-chordates (Invertebrates). Connecting Concepts Protozoans are single celled Eukaryotes (classified in Kingdom Protista). The porifers to In parazoans ‘animal pole’ of the chordates, all multi-cellular, are called metazoans (placed in Kingdom Animalia). The metazoans egg (zygote) develops into Endoderm are further differentiated into Parazoans and Eumetazoans. The group ‘Parazoa’ includes porifers, and ‘Vegetal pole’ into ectoderm. In having cellular grade of organization, and ‘Eumetazoa’ includes Coelenterates (Cnidarians) to Eumetazoans it is just reverse. chordates. The following account will be useful in understanding complexity, the basis of classification and the terminology used in higher forms. Grade or Level of organization - There are 5-grades of organization in animals. 1. Sub-cellular / Protoplasmic grade of organization - This level of organization is present in protozoans or single celled organisms. The different functions of the body are carried out by different organelles of the cell. In Amoeba and Paramecium, for example, the osmoregulation is carried out by contractile vaccuole and the locomotion by pseudopodia and cilia respectively. 2. Cellular grade of organization - This occurs in porifers where individual function is performed by a particular cell. The choanocytes, for example, by flagellar beating create water current for filter feeding; the thesocytes store reserve food material; the scleroblasts form spicules and myocytes are related with the contractile functions, and so on. 3. Tissue / Cell-tissue grade of organization - It has developed in Cnidaria and Ctenophora where specific tissues, like nervous tissue, gonadal tissue and other such structures have been developed. 4. Organ / Tissue-organ grade of organization - It is found in flat warms (Platyhelminthes) where various types of tissues have been organized to form organs, like brain, excretory organs etc. 5. System/Organ-system grade of organization - From Aschelminthes to Chordata, all have organ system - grade of organization. They have developed various systems, like digestive, reproductive, respiratory and circulatory etc. upto various degree of complexity.

Body Wall In metazoans the body developes from two or three germ layers i.e., ectoderm and endoderm, or the ectoderm, mesoderm and endoderm. 1. Diploblastic Body Wall - eg. Porifers and Cnidarians The body of the organism developes from two germ layers, i.e., ectoderm and endoderm, cemented together by mesoglea, a non-cellular layer. 2. Triploblastic Body Wall - eg. Platyhelminthes to Chordates The body of such animals develop from all three germ layers, i.e., ectoderm, mesoderm and endoderm.

Symmetry

Fig. 4.1 : Biradial symmetry

Some of the protozoans like Amoeba, Entamoeba, and most of the porifers are assymmetrical. But the higher forms have a specific symmetry. There are 4-major types of symmetry in animal kingdom. 1. Radial symmetry - eg. Cnidarians (except Anthozoans) and Echinoderms. In Cnidarians body is cylindrical, and if cut longitudinally through any radius, the two halves will be morphologically identical. The right and left, or the dorsal and ventral sides, in such symmetry are not differentiated. The radial symmetry is advantageous to sessile (attached) animals as they can feed from all directions. 2. Bilateral symmetry - eg. Platyhelminthes to Molluscs, and all chordates. The body of such animals can be differentiated into right and left halves because they show lateral - symmetry. The body can be cut longitudinally (sagittal section) into two equal

ANIMAL KINGDOM (PART-I & II) 3.

4.

113

halves only through one axis, i.e., dorsoventral. Biradial symmetry - eg. Anthozoans (Cnidarians) and Ctenophores Such animals show similar parts on either side of the body axis, such that, each of the four sides of the body is identical to the opposite side but is different from the adjacent side. It is different from tetraradial symmetry. Moreover, the internal organization of such animals is always bilateral. Spherical symmetry - eg. Some protists (Volvox) The body in such organisms is ball-shaped or spherical and both longitudinal and equational cut can produce to similar halves.

Body Plan There are 3-types of body plans, mainly depending upon the presence or absence, or the complexity, of the gut. 1. Cell-aggregate Body Plan - eg. Porifers The gut is not differentiated and the digestion is wholly intracellular. The whole body consists of a group of well differentiated cells. 2. Blind sac Body Plan - eg. Cnidarians, Ctenophores and Platyhelminthes The gut cavity has a single, ‘mouth’ opening. The anal opening is absent. The alimentary (a) (b) canal is, therefore, a blind sac. The undigested waste in such cases is also removed through Fig. 4.2 : (a) ‘Blind sac’ body plan; the same opening. (b) ‘Tube-within-tube’ 3. Tube-within-Tube Body Plan - eg. Aschelminthes to Chordates body plan The gut is complete, tubular and more complex with separate mouth and anal openings.

Coelom It is a body cavity present between the body wall and gut. On the basis of body cavity the animals can be differentiated into three categories. 1. Acoelomates - eg. Porifers, Cnidarians and Platyhelminthes In such animals, either the gut is not differentiated (eg. Porifers) or if it is differentiated (eg. Gastrovascular cavity of Cnidarians or incomplete gut of Platyhelminthes) then there is no cavity between body wall and the gut. In Platyhelminthes, the space between ectoderm and endoderm is filled with mesodermal tissue. 2. Pseudocoelomates - eg. Aschelminthes (Nematodes) and Rotifers When the body cavity, in between body wall and the gut, is lined by mesoderm, only on one side, i.e., towards body wall, it is called Pseudocoel. Such cavity represents persistant blastocoel. The gut cavity in such animals is not muscular (mesoderm absent around gut) and the organs also lie loose (mesenteries absent). 3. Eucoelomates - eg. Annelids to Chordates The eucoelomate animals have ‘true coelon’, i.e., a body cavity lined with mesoderm on both the sides. The mesodermal / muscular lining allows the organs to move independently. The organs in true coelon are held in place by mesenteries. On the basis of origin the true coelon is of 2-types. (a) Schizocoel - eg. Annelids, Arthropods and Molluscs Such coelom developes by the splitting of mesodermal segments. (b) Enterocoel - eg. Echinoderms and Chordates This type of coelom developes by pouching or outpocketing of the archenteron (cavity of gastrula).

Connecting Concepts The Haemocoel (in open blood vascular system) is present in all Arthropods, and a few annelids and molluscs. Such blood filled cavity is persistent blastocoel. The true coelom, in such cases, is greatly reduced. (Please remember that haemocoel is not a true coelom).

114

BIOLOGY ectoderm

pseudocoelom

ectoderm

mesoderm

mesentery

endoderm

endoderm coelom

mesoderm digestive cavity (a)

(b)

(c)

Fig. 4.3 : (a) Acoelomate; (b) Pseudocoelomate; (c) Eucoelomate

Protostomes and Deuterostomes - eg. All Eucoelomates In Protostomes (eg. Annelids, Arthropodes and Molluscs) the mouth appear at the site of blastopore (Gk. protos - first, stoma - mouth) and Anus developes later, opposite to mouth opening. In Deuterostomes (eg. Echinoderms and chordates) the anus developes at the site of blastopore and mouth developes later, as a second opening, opposite to the anal opening (Gk. Deuteros - second, stoma - mouth). 1.

2.

3.

4.

Protostomes

Deuterostomes

Blastopore (opening of the archenteron cavity of gastrula) is associated with the formation of mouth. The pattern of Cleavage in embryo is spiral i.e. the daughter cells of a new tier lie obliquely (spirally), at the junction of previous cells. (Due to large amount of yolk the cleavage in arthropods is highly modified, i.e. being superficial meroblastic. The fate of cleavage is determinate or fixed. The separated cells at 4-celled stage cannot form complete embryos, since the structure to be developed by missing cells will not be formed. Coelom is true – Schizocoel (type)

Blastopore is associated with the formation of Anus.

blastopore Check Point 1. Differentiate between: (i) Schizocoel and Enterocoel (ii) Protostomes and Deuterostomes (iii) Diploblastic and Triploblastic condition (iv) Parazoa and Eumetazoa (v) Metagenesis and Metamorphosis

The pattern of cleavage in embryo is radial i.e., the daughter cells of a new tier lie vertically at the top or bottom of the previous cells.

The fate of the cleavage cells is indeterminate. The separated cells at 4-celled stage can form complete (though smaller) embryos as the individual cells have no definite fate. Coelom is true– ‘Enterocoel’ (type) mouth

8-cell stage

top view

side view

spiral and determinate cleavage

primitive gut

schizocoelom archenteron

anus

Fig. 4.4 : PROTOSTOMES

coelom formed by the splitting of the mesoderm

ANIMAL KINGDOM (PART-I & II) blastopore

8-cell stage

top view

115 anus

archenteron enterocoelom

side view primitive gut

radial and indeterminate cleavage

mouth

coelom formed by an outpocketing of primitive gut

Fig. 4.5 : DEUTEROSTOMES

Anamniota and Amniota Amongst higher vertebrates (eg. Reptiles, Birds and Mammals) the development of the eggs is either outside the body (oviparous) and the eggs are Cleidoic (shelled or box-like), or it is inside the body (Ovoviviparous or viviparous), and the eggs are non-cleidoic. All such animals have extra embryonic membranes, i.e., amnion, chorion and allantois (yolk sack also) either to face terrestrial environment or for the formation of placenta. Such animals are called amniotes (with amnion). The lower vertebrates, without amnion, or other extra-embryonic membranes are, therefore, called Anamniotes. The Anamniotes include cyclostomes, fishes and amphibians.

PHYLUM PROTOZOA      

Protos—first, Zoan—animal, First animal phylum Study of protozoans called Protozoology Father of protozoology – Antony von Leeuwenhoek Term Protozoa was assigned by Goldfuss Protozoa belongs to Kingdom Protista of Haeckel Single -celled, solitary or colonial, eukaryotes

Important characters     

      

Size ranges from 1µ to 5000µ Aquatic – fresh water or marine forms, or endoparasites Grade of organization- protoplasmic or subcellular Locomotion by cilia, flagella or pseudopodia, or absent Skeleton – may or may not be present; if present then either calcareous or siliceous .Foraminifers have external shell of CaCO3 ( ex. Polystomella), whereas Radiolarians have internal plates of silica Osmoregulation by contractile vacuole in fresh water protozoans (isotonic to 0.8 % NaCl solution). C.V. absent in parasitic and most of the marine forms. Symmetry—radial, bilateral or absent (assymetrical) Nutrition—Holozoic or holophytic. Digestion intracellular within food vacuole. Reserve food material- Glycogen or Starchlike bodies Respiration – exchange of gases occurs through plasma membrane Excretion –excretory product NH3 (Ammonotelic). Excretion occurs through general body surface or plasmalemma. Blood and nervous tissue absent. Sensory structure stigma (eye spot) present in Euglena Reproduction – Asexual or Sexual. Asexual by budding, spore formation , binary fission or multiple fission. Sexual by Conjugation ((Paramecium) or gamete formation ((Plasmodium)

Check Point 1.

2.

What are locomotory structures in the following protozoans: Trypanosoma, Babesia, Paramecium, Opalina, Euglena, Leishmania Name the diseases caused by Entamoeba histolytica, Leishmania donavani, Plasmodium, Trypanosoma gambience

116

BIOLOGY

Euglena

Trypanosoma

Polystomella

Amoeba

Paramecium Fig. 4.6

CLASSIFICATION Basis of classification – Locomotory structures 1.

Sub Phylum Sarcomastigophora

(i)

Super Class Mastigophora (Flagellata) — 

Locomotory structures- flagella



Most primitive class



Binary fission –longitudinal

Two subdivisions- Phytomastigophora and Zoomastigophora Phytomastigophora Green Chloroplast present Mostly free living Reserve food material ––starch (paramylon bodies) Flagella- 1 to 2 ex. Euglena, Volvox, Noctiluca and Ceratium Noctiluca –shows bioluminescence, called Burning of sea

Zoomastigophora Non green Chloroplast absent Mostly parasites Reserve food material –Glycogen Flagella 1 to many e x . Tr y p a n o s o m a , L e i s h m a n i a , Giardia, Trichomonas, Trichonympha, Proterospongia, Mastigamoeba

T. brucei—digenetic parasite, primary host-cattle and secondary host - a fly; Disease- Nagana T. cruzi—digenetic parasite, primary host- man and secondary host - dipteran fly; Disease- Chagas T.evansi T.evansi—digenetic parasite, primary host –horse and secondary host - Horse fly(Tabanus); Disease- Surra (skin disease) Trichomonas - T. tenax aggrevates pyrrhoea, T. vaginalis causes leucorrhoea. Leishmania donovani donovani— a digenetic parasite, primary host- man and secondary host - Sand fly(Phlebotomus ( (Phlebotomus ); Disease- Kala azar(Dumdum fever) L. tropica tropica—causes Oriental sore or Delhi boil / Skin Leishmaniasis Giardia— a bilaterally symmetrical form, commonly called ‘Grand old man of intestine’; Giardia causes Diarrhoea Trichonympha - It is a symbiotic protozoan in the gut of termites, for cellulose digestion.

ANIMAL KINGDOM (PART-I & II) (ii)

117

Super Class Sarcodina (Rhizopoda)

Locomotory structures-Pseudopodia ( false legs)



Free living or parasitic forms



Includes Heliozoans, foraminifers, radiolarians and amoebids

ex. Amoeba, Entamoeba, Polystomella, Arcella, Pelomyxa and Babesia (a RBC parasite, transmitted through tick and causes Texas fever in cattles) Entamoeba histolytia - a monogenetic parasite in colon (large intestine) of man; causes Amoebiasis or Amoebic dysentry. Infective stage - Tetranucleated cyst. Mode of infection - contaminated food and water. E. gingivalis (or buccalis) - a monogenetic parasite in the pockets, between teeth and gums; aggrevates pyrrhoea. Infective stage - Trophozoite. Mode of infection - Mouth to mouth kissing. E. coli - a commensal of colon. 2.

Subphylum Ciliophora (Class Ciliata) – 

The biggest and the most advanced class of protozoa



Binary fission – Transverse



Nuclei dimorphic, Micronucleus- reproductive and Macronucleus- vegetative in function.

ex. Paramecium, Vorticella and Rectal ciliates. Rectal ciliates –found in the rectum of frog and toad, include Balantidium, Nyctotherus and Opalina. Opalina has multinucleated condition. (micro- and macro- nuclei not differentiated). Though the locomotory structures in Opalina are cilia, but due to multinucleated condition, it is sometimes included in superclass Opalinata. 3.

Subphylum Sporozoa 

Locomotory structures absent



Members most specialized for parasitic mode of life.



Exclusively endoparasites (contractile vacuole absent)

ex. Plasmodium, Monocystis and Eimeria Monocystis- endoparasite in the seminal vesicle of earthworms, feeding on sperms Eimeria- causes coccidiosis in poultry birds 4.

Subphylum Cnidospora 

Spore formation throughout life



Spores contain polar capsule, and coiled filament for attachment



Trophozoite - multinucleated

ex. Nosema, Myxidium (Nosema bombysis causes ‘Pebrine’ disease in silk worm, Bombyx mori).

PHYLUM PORIFERA 

Pore bearing animals



2-types of pores, Ostia- incurrent pores, Osculum- excurrent pore; Ostium act as mouth and osculum as anus. A sponge thus has many ‘mouths’ but one ‘anal’ opening



Term porifera was given by Grant, but Animal - nature of sponges was established by Ellis.



Porifers are multicellular animals (most primitive metazoans).

Connecting Concepts The group Metazoa is divided into Parazoa and Eumetazoa. Porifers belong to parazoa as ectoderm in these animals develops from vegetal pole and the endoderm develops from animal pole. In eumetazoans it is just reverse.

118

BIOLOGY 

Commonly called sponges, and study of sponges is called, ‘Parazoology’



All aquatic- mostly marine, and free living (not parasites)



All Sessile (attached to substratum) i.e., the locomotory structures are absent in adults.



Cellular grade of organization



Maximum regeneration power present



Cell aggregate body plan



Radially symmetrical or asymmetrical



Skeleton consists of spicules or spongin fibres



Body wall diploblastic, mesoderm absent



Mesoglea- non-cellular and jelly like



Body cavity – Spongocoel or Paragastric cavity



Coelom absent – acoelomate animals



Canal system present- a characteristic feature of porifers



Respiration – aerobic and through general body surface



Excretion – Ammonotelic and excretion through general body surface



Nutrition – all filter- feeders, Digestion - intracellular

  

(The animals which create water current with ciliary or flagellar beating and pick-up the food particles from it, are called filter feeder). Blood absent Nervous tissue absent Reproduction- Asexual and sexual both. Mostly bisexual. Asexual reproduction by budding or by gemmule formation (in fresh water forms).In sexual reproduction the development is indirect. Larva is Parenchymula or Amphiblastula

Body wall  

 

Ectoderm consists of Pinacocyte cells – thin and polygonal Endoderm consists of funnel shaped Choanocyte cells or Collar cells. The collar is formed by a number of microvilli. Choanocytes are the characteristic cells of porifers. These cells create water current for filter feeding. Mesoglea contains wandering cells called Amoebocytes Amoebocytes are of 6-7 types: 1. Archeocytes – undifferentiated and totipotent cells which can transform into any type of amoebocytes. 2. Myocytes- Contractile cells present around openings. They are formed from Pinacocytes. 3. Collenocytes- connective tissue type cells 4. Thesocytes – food storing cells 5. Scleroblasts- skeleton (spicules) forming cells, or spongioblasts - forming spongin fibres. 6. Germ cells- for reproduction

Canal system It circulates water for feeding , respiration, excretion , reproduction etc. 3- types Ascon type, Sycon type and Leucon type 1.

Ascon type- It is the simplest canal system in which water circulates from osculum

ostia Outside  → Spongocoel → Outside

2.

Sycon type- It consists of Radial canal or Flagellated chamber, lined with Choanocytesthe flagellated cells. The water circulates from

ANIMAL KINGDOM (PART-I & II)

119 apopyle

ostia prosopyle → → Incurrent canal  Outside   → Radial canal  osculum

Spongocoel → Outside 3.

Leucon type (Rhagon type) – It is the most complicated canal system , and water circulates from ostia

prosopyle

inner apopyle Outside  → Incurrent canal  → Radial canal  → outer apopyle

osculum

Excurrent canal  → Spongocoel → Outside Rhagon type of canal system is present in the larvae of animals which have Leucon type of canal system in adults. ENDOSKELETON –consists of spicules or spongin fibres Spicules- Calcareous ( calcium carbonate) or Siliceous( silica). Calcareous spicules are monoaxon or triaxon type while siliceous are 6- rayed, 4- rayed or amphidisc type. Examples of porifers : Spongilla (fresh water sponge), Euspongia (Marine Bath Sponge) and Sycon (Scypha)

Leucosolenia

Euplectella

Sycon

Connecting Concepts

Euspongia

Spongilla Fig. 4.7

*Classification - It is based on skeleton (not canal system) 1.

Class Calcarea  Spicules calcareous type and monoaxon or triaxon in nature  All marine  Canal system Ascon or Sycon type ex. Leucosolenia(simplest sponge), Clathrina, Grantia and Sycon(Scypha) In Leucosolenia (Olynthus type sponge) the larva is Amphiblastula while in Clathrina it is Parenchymula. In Sycon again it is Amphiblastula

2.

Class Hexactinellida ( Hyalospongia)—  Commonly called glass sponges( semitransparent type)  All marine  Canal system Leucon type  Spicules siliceous and 6- rayed. ex. Euplectella (Venus flower basket) –a wedding gift and symbol of ‘Union till death’ or ‘Till death do us apart’. Hyalonema- (Glass rope sponge)

3.

Class Demospongia –  Marine or fresh water forms

* For NEET, only salient features- up to Phylum level, are to be studied.

In young stages of Euplectella when sieve plate of osculum has not been formed, the young crustaceans, Spongicola, (male and female) enter into its body. Later when sieve plate developes they cannot escape and remain there till death. Hence, it is a symbol of union till death.

120

BIOLOGY  Canal system Leucon type  Spicules , if present , siliceous but not 6-rayed  Spongin fibres present or absent ex. Cliona-Boring sponge, bores in molluscan shells and is detrimental to pearl industry Chalina – dead man’s finger; Euspongia- common bath sponge (spicules absent and spongin fibres present) ; Spongilla- common fresh water sponge, Ephydatia- also a fresh water sponge. Hippospongia - Horse sponge. The fresh water sponges also produce Gemmules for asexual reproduction.

PHYLUM CNIDARIA (COELENTERATA)                 

Check Point 1. Fill in the blanks with suitable words: (i) Alternation of generation in hydrozoans is called ................................................... (ii) The characterstic cells of Cnidarians are ........................... (iii) ...................................... is called Venus flower basket. (iv) The members of class ................. of Cnidaria show Biradial symmetry. (v) Larvae in Aurelia are ................. and ..................

Term Coelenterata (also called Cnidaria) is given by Leuckart Characteristic point – the presence of Nematoblasts or Cnidoblasts (Stinging cells) Radially or Biradially symmetrical Aquatic- mostly marine Sessile or free-swimming in nature Cell- tissue grade of organization Blind-sac body plan Locomotory structures- Tentacles Body wall- Diploblastic ( Ectoderm and endoderm with mesoglea) Body cavity – Coelenteron or Gastrovascular cavity Coelom absent ––Acoelomate Solitary or colonial. Colony monomorphic, dimorphic or polymorphic Respiration- aerobic, through general body surface Excretion- through general body surface, excretory product- NH3 (ammonotelic) Digestion- partly extracellular (in coelenteron, hence called Gastrovascular cavity) and partly intracellular (in nutritive cells). Undigested food material is removed through mouth. Nervous tissue developed for the first time- in the form of network of neurons(nonpolarized).The brain and nerves are absent. Reproduction- asexual or sexual or both. Asexual by budding. In sexual reproduction , development is direct or indirect. Larva Planula or, Planula and Ephyra. Two main forms— polyp and medusa MEDUSA POLYP 1. Umbrella or cup-shaped Tubular 2. Tentacles solid Tentacles hollow or solid 3. Tentaculocysts (Balancing struc) present Tentaculocysts absent 4. Reproductive form Mainly feeding form 5. Always free swimming Sessile or free swimming 6. Only sexual reproduction present Asexual or sexual reproduction 7. Dioecious forms Monoeceous or dioecious forms Examples of coelenterates : Adamsia (Sea anemone), Pennatula (sea pen), Gorgonia (Sea fan), Physalia (portuguese man of war)

Aurelia (Medusa Form)

Cnidoblast

Adamsia (Polyp Form)

* For NEET, only salient features- up to Phylum level, are to be studied.

Hydra wth bud

ANIMAL KINGDOM (PART-I & II)

Physalia

121

Obelia Fig. 4.8

Gorgonia

* Classification – This phylum is divided into 4-Classes 1. CLASS HYDROZOA—  Fresh water or marine forms  Polyp forms or polyp and medusa forms. If polyp and medusa both forms present, there is an alternation of generation called Metagenesis (It is not true alternation of generation as both the forms are diploid)  Polyp stage- without pharynx  Mesoglea thin  Germ cells derived from ectoderm only  Nematoblasts or stinging cells also derived from ectoderm ex. Hydra- a fresh water form with direct development. Obelia- It is commonly called sea fur and shows metagenesis. It has indirect development with Planula larva. Physalia- commonly called Portuguese man of war- with polymorphic colony showing different type of zooids (individuals) under one pneumatophore. 2. CLASS SCYPHOZOA—  All marine forms  Only medusa form present (Metagenesis absent)  Mesoglea very thick and jelly like , so called jelly fishes  Germ cells develop from endoderm  Nematoblasts present in both ectoderm and endoderm  Tentaculocysts present  Asexual reproduction absent  All forms dioecious ex. Aurelia- common jelly fish. In Aurelia besides Planula , the Ephyra larva is also present 3. CLASS CUBOZOA —  All marine forms  Medusae, as compared to polyps, are for longer duration  Medusae are squarish (not circular), so called Cubozoans  Eyes most complicated for detecting light. ex. : Chironex (sea wasp) - contains deadly poisonous nematocysts which are fatal for human also. 4. CLASS ANTHOZOA OR ACTINOZOA—  It is the largest class of Cnidarians  All marine forms  Only polyp form present (Medusoid Medusoid stage completely lacking lacking), so metagenesis absent  Polyp has pharynx  Mesenteries are also present  Germ cells develop from endoderm  Nematoblasts present in both ectoderm and endoderm  Symmetry- Biradial  Most of the forms secrete exoskeleton of corals. The coral of solitary form is called Corallium but of colonial forms – Coral reef reef. CORAL REEFS – 3 types

122

BIOLOGY 1. 2.

Fringing reef reef—when the coral reefs are close to sea shore Barrier reef – When the coral reefs are away from the sea shore. ex. The coral reef of Australia—It is the largest coral reef covering about 2000 km. area. 3. Atoll reef reef—When the reef is in the form of a ring surrounding water body called Lagoon ex. Sea anemone (Adamsia ( or Metridium), Sea pen (Pinnatula ( ), Sea fan (Gorgonia), Pipe coral (Tubipora)) and Mushroom coral ((Fungia), Red coral, Moonga (Corallium rubrum).

PHYLUM CTENOPHORA   

     

          

A minor phylum with less than 100 species Ctenophores are colourful, jelly-fish-like ( similar to medusa form of Cnidarians), transparent animals with well -marked Bioluminescence. Commonly called Comb-jellies because of comb plates ( 8 ) or paddle plates or ciliary plates, for locomotion – characteristic feature of ctenophores. They are also known as Sea Goose berries or Sea walnuts (because of their shape) . Free swimming (Pelagic), exclusively marine and solitary forms. Symmetry – Biradial and tetramerous. (In NCERT books, it is mentioned as Radial Symmetry) Acoelomate (coelom absent). Tissue grade of organization. Blind sac body plan. Mouth, at one end, opening into endodermal gastrovascular cavity through pharynx, and the sensory organ at opposite end. Nematocysts absent, but tentacles ( generally one pair ) bear adhesive cells called Colloblast or Lasso cells for capturing the prey, ((Euchlora rubra, however, lacks colloblast but contains nematocysts ). Body unsegmented, body wall is Diploblastic but advanced type Epidermis is ciliated and the mesenchyma/mesoglea contains muscle fibres, connective tissue and amoeboid cells. Polymorphism absent. Statocyst, a balancing organ, present. Carnivores, feeding on eggs and larvae of crustaceans and mollusks. Skeletal, respiratory, excretory and circulatory systems are absent. Brain absent, but a diffuse network of neurons present. Reproduction - only sexual type. Asexual reproduction absent, but great power of regeneration present. All bisexual (hermaphrodite), gonads endodermal in origin . Fertilization external or internal. Cleavage complete, determinate and dissymmetrical. Development indirect and the larva, Cydippid, Cydippid is present ( Planula larva is absent). The alternation of generation (metagenesis) is also absent Some ctenophores show ‘Dissogeny’, in which both larvae and adults become sexually mature. Paedogenesis is common

Taxonomic position   

Some zoologists still include Cnidaria and Ctenophora (Acnidaria) in Phylum Coelenterata. Ctenophores are also known as missing links between Cnidaria and Platyhelminthes. They are also considered to be intermediate between radiata and bilateria. Ctenophores perhaps represent a blind off- shoot which has not given rise to higher forms. Some features however, indicate their common origin with Cnidaria. Examples of ctenophors : Ctenoplana, Beroe, Pleurobrachia

* For NEET, only salient features- up to Phylum level, are to be studied.

ANIMAL KINGDOM (PART-I & II)

123

(a) (b) Fig. 4.9 : (a) Pleurobrachia; (b) Beroe

*Classification – 2- classes 1. Tentaculata  Adults with two aboral tentacles or oral lobes. eg. Cestus (Venus’s girdle), Ctenoplana, Pleurobrachia 2. Nuda  Tentacles or oral lobes absent in both adults and larval forms. e.g., Beroe

PHYLUM PLATYHELMINTHES Τerm Platyhelminthes is given by Gegenbaur Dorsoventrally- flattened animals. Commonly called Flat worms. Tissue- organ level of body organization Cephalization appeared for the first time Bilaterally symmetrical Acoelomate Body wall Triploblastic ( Body develops from 3- germ layers) Excretory structures –Flame cells ( Protonephridia or Solenocytes), developed for the first time  Aquatic or terrestrial  Free-living or parasite  Blind sac body plan- Mouth present but anal opening absent  Alimentary canal incomplete and branched. Digestion extracellular  Respiration- aerobic in free living forms but anaerobic in parasitic forms  Locomotion by suckers or ciliated skin  Nervous tissue well developed. Brain present  Blood or Blood vascular system absent  Reproduction- asexual, by transverse fission, or sexual . Fertilization self or cross. Development direct or indirect Examples : Planaria, Taenia (Tapeworm) Fasciola (liver fluke)        

Planaria * CLASSIFICATION — 3- classes 1. CLASS TURBELLARIA

Tapeworm

Liver Fluke

Fig. 4.10 :

* For NEET, only salient features- up to Phylum level, are to be studied.

Blood Fluke

124

BIOLOGY Commonly called flat worms Body unsegmented Locomotion by gliding or crawing with the help of ciliated epidermis. The epidermis also contains small rod-shaped bodies, called Rhabdites of uncertain function.  Aquatic or terrestrial and Free living  Suckers absent  Intestine branched  Bisexual (monoecious)  Regeneration present and is morphallaxis type  Asexual reproduction by transverse fission  In sexual reproduction – development direct or indirect ( Muller’s larva) ex. Planaria (Dugesia ( )—Fresh water form. Mouth in the middle of the body. Eye spots in the head. Development direct Bipalium—Terrestrial and burrowing CLASS TREMATODA :  Commonly called Flukes  Body unsegmented  Suckers present  Endoparasites  Intestine branched  Unisexual (Blood fluke) or bisexuals  Asexual reproduction absent  Regeneration absent  Development indirect in sexual reproduction ex. Blood fluke (Schistosoma)- Its female individual lies in the gynaecophoric canal of male. It is a digenetic parasite ((primary primary host - Human/other mammal; secondary host snail), and causes Schistosomiasis or Bilharzia. Liver fluke ((Fasciola hepatica) – It is endoparasite in the liver of sheep or goat etc. Shows Heterogenesis or Polyembryony 5-types of larval stages—1.Miracidium, 2.Sporocyst, 3.Redia, 4.Cercaria and 5.Metacercaria Fasciola hepatica is a digenetic parasite, primary host is sheep or goat and secondary host is a mollusc- Planorbis or Limnaea. (Miracidium is the infective stage for Planorbis, whereas Metacercaria is the infective stage for sheep). CLASS CESTODA:  Commonly called Tape worms  Body segmented. The segmentation is false and called Strobilization. The segments are called proglottids.  Suckers present for attachment  Endoparasite  Mouth as well as gut is lacking. Digested food is absorbed through skin (osmotroph) and the Scolex is, therefore, not called ‘Head’.  Bisexual (Monoecious)  Regeneration absent  Asexual reproduction lacking  Development indirect ex. Taenia solium (Pork tapeworm)- a digenetic parasite, primary host - man and secondary host - pig. Larva- Bladderworm or Cysticercus (Infective stage for human is cysticercus larva, and for pig it is onchosphere stage. Mode of infection - through improperly cooked pork.) Taenia saginata (Beef tapeworm) - Primary host - Man and secondary host - cattle, and   

2.

3.

Check Point 1.

Write the names of primary and secondary hosts of the following parasites: (i) Wuchereria bancrofti (ii) Fasciola hepatica (iii) Taenia solium (iv) Dracunculus medinensis (v) Plasmodium (vi) Trypanosoma gambience

* NEMATODA is considered to be a class of phylum Aschelminthes , or a (minor) phylum, if Aschelminthes is taken to be a superphylum.

ANIMAL KINGDOM (PART-I & II)

125

Echinicoccus (Dog tapeworm)

PHYLUM ASCHELMINTHES 

              

Aschelminthes is a heterogenous group and includes Nematoda, Rotifera, Acanthocephala, Gastrotricha and Nematophora, all pseudocoelomate groups Nematoda* is the largest group of Aschelminthes and shows following features : Commonly called ROUND WORMS or THREAD WORMS- all True worms. Cylindrical, triploblastic and bilaterally symmetrical Body unsegmented Free living (ex. Rhabditis) or parasites (in animals as well as plants). Anguina and Heterodera are plant nematodes of wheat and potato crop respectively. Pseudocoelomate (Pseudocoelom is persistent blastocoel) Tube within tube body plan (Alimentary canal complete with mouth and anal opening) Excretory structures – Rennette cells Respiratory and circulatory system absent. Number of cells in different parts of the body, throughout life, is fixed. This numerical constancy of cells/nuclei in the body organs, is called Eutely. Since the number of cells remains constant, the growth in the body occurs by increase in the size/volume of the cells. Such growth is called Auxetic growth. Asexual reproduction and regeneration absent Unisexual (Dioceous). Sexual dimorphism prominent Sperms amoeboid (Tail absent) Clearage determinate and spiral. Development indirect. Larva – Rhabditiform or Rhabditoid (resembling a free-living form - Rhabditis) ex. Ascaris (Round worm)- It is endoparasite in small intestine of human, particularly children. It is a monogenetic parasite. Infective stage for human is Embryonated egg, or egg having II instar larv. Ancylostoma duodenale (Hook worm) - It is monogenetic parasite of small intestine. Infective stage is larva or Juvenile, which pierces through the soft skin. Oxyuris or Enterobios vermacularis (Pin worm or seat worm) – It is monogenetic parasite of human intestine. Infective stage eggs, and infection occurs through contaminated food and water. Wuchereria bancrofti (Filaria worm) – This worm is a digenetic parasite of lymph (not intestine). Primary host – man, secondary host-female Culex. Infective stage –microfilariae, and disease Filariasis or Elephantiasis. Dracunculus medinensis (Guinea worm or serpent worm) – Male forms rarely found. It is Viviparous and subcutaneous parasite. Digenetic , Primary host- man , secondary host- Cyclops (crustacean- an arthropod). Other important nematodes are Loa loa (Eye worm), Trichinella spiralis (Muscle worm) and Trichuris trichura (whip worm).

(a) (b) Fig. 4.11 : (a) Male Ascaris; (b) Female Ascaris

(a)

(b)

PHYLUM ANNELIDA       

Body segmented. Segments ring –shaped True segmentation (Metamerism* ) present. Number of segments fixed, new segments not added and old ones not removed. Segments (true) called metameres. Term Annelida – by Lamarck Aquatic or terrestrial Free living or parasite Triploblastic and bilaterally symmetrical (c) Locomotory structures – Setae and Parapodia Fig. 4.12: (a) Nereis; (b) Aphrodite;

* For NEET, only salient features- up to Phylum level, are to be studied.

(c) Leech

126

BIOLOGY      

 

Body plan – TUBE WITHIN TUBE Eucoelomate – true coelom (Schizocoel) present Alimentary canal well differentiated with mouth and anal opening Respiration through gills or branchie , cirri and skin Excretory structure- Nephridia Blood vascular system present and has developed for the first time. Blood pigment is dissolved in plasma.The RBCs are absent. The blood vascular system is OPEN OR CLOSED TYPE. Out of 4-major types of respiratory (blood) pigments, i.e. Haemoglobin, Haemoerythrin, Chlorocruonin and Haemocyanin, the first three are present in Annelida. Haemocyanin is absent in annelids but is present in molluscs and arthropods. Nervous system includes CNS, PNS and ANS. Ventral nerve cord is ganglionated. Unisexual or bisexual forms. Reproduction sexual only. Fertilization external or internal. Development direct or indirect. If indirect the larva is Trochophore. Examples : Pheretima (Earthworm), Hirudinaria (Leech), Nereis (sand worm

* CLASSIFICATION—3- classes 1. CLASS POLYCHAETA : poly- many; chaetae- setae  All marine  Locomotory structures- parapodia  Head differentiated. Eyes present on head. Clitellum absent  Carnivorous  Blood vascular system – closed type  Unisexual (Dioecious). Fertilization external in water.Development indirect- larva Trochophore ex. Neanthes or Nereis (Rug worm or clam worm or sand worm), in breeding season called Heteronereis. Chaetopterus (Paddle worm) – shows bioluminescence, Aphrodite (Sea mouse), Arenicola (Lug worm) Sabella, Polygordius. (Aphrodite ( is also the name of a Greek Goddess of beauty, love and fertility). (Polygordius, due to absence of Parapodia, is also classified in a separate class, i.e. Archiannelida). 2. CLASS OLIGOCHAETA : oligo- few, chaetae- setae  Terrestrial  Parapodia absent . Head not differentiated. Eyes lacking  Soilivorous  Clitellum present throughout life  Bisexual forms. Fertilization external but in cocoon. Development direct- larva absent. ex. Pheretima (Earthworm), Lumbricus (European earthworm), Megascolex (South Indian earthworm), and Tubifex (it lives in muddy or highly polluted water. It can tolerate very low level of oxygen, and hence is used as an indicator of water pollution. It is bright-red in colour and is commonly called as ‘Blood worm’.) 3. CLASS HIRUDINEA : Hirudin – an anticoagulant in saliva, present  Setae and parapodia absent  Aquatic- mostly marine  Head not differentiated. Eyes 5-pairs  Sanguivorous – blood sucking. Ectoparasites on vertebrates  BVS- is OPEN TYPE, and is called Haemocoelomic system.  Clitellum develops only during breeding season  Bisexual. Fertilization internal and development direct. ex. Hirudinaria (Leech)- Number of segments in leeches is 33. Leeches also have Botryoidal tissue—supposed to be excretory in nature ; Hirudo (European leech); Pontobdella- ectoparasite on fishes. *Besides Annelida, the metameric segmentation is also shown by the members of phylum Arthropoda and phylum Chordata.

ANIMAL KINGDOM (PART-I & II)

127

PHYLUM ARTHROPODA            

Arthros – jointed , podos – legs, i.e. animals with jointed legs or appendages Term Arthropoda – by Von Siebold It is the largest phylum of the animal kingdom, covering about 80 % of the animals Aquatic, terrestrial or aerial (only non-chordates which can be aerial). Exoskeleton of Chitin- a polysaccharide of N-acetylglucosamine Periodic removal of exoskeleton called Ecdysis or moulting- essential for growth Metamerically segmented Blood vascular system Open type (Capillaries –nt, Haemocoel +nt) . Blood pigment present or absent (insects). If present it is Haemocyanin (having Cu instead of Fe) Respiratory structures- Gills, Book lungs and Tracheal tubes Excretory structures- Green glands (Antennal glands), Coxal glands and Malpighian tubules Nervous system very well developed. Eyes simple or Compound Unisexual (Dioecious) with well marked sexual dimorphism. Fertilization internal. Development mostly indirect. Examples : Scorpion, Prawn, Mosquitoes, Honeybee, Silkworm. Butterfly, Lac insect, Limulus (king crab)

Butterfly

Silverfish

Grasshopper

*CLASSIFICATION — 4- subphyla 1.

Subphylum ONYCHOPHORA : Onychos- claws, phoros- bearing ex. Peripatus (Walking worm) – a living connecting link between Annelida and Arthropoda. The presence of excretory ducts and unjointed legs, like parapodia, are annelidan characters, and the presence of antennae and tracheal respiration are arthropodan characters.

Scorpion

(Onychophora is no longer a subphylum, but has now been raised to phylum level.) 2.

Subphylum TRILOBITA : Tri – three. Body 3- lobed, ex. Giant arthropods – all extinct

3.

Subphylum CHELICERATA : 2- classes A.

Class MEROSTOMATA : order – Xiphosurida

Spider

ex. Limulus (King crab or Horse Shoe crab) – a living fossil with compound eyes. B.

Class ARACHNIDA : Arachne – spider, oid – like 

Chelicerae – 1 pair, comparable to mandibles



Pedipalps – 1 pair, comparable to maxillae



Walking legs – 4 pairs



Body is diffentiated into Prosoma (cephalothorax) and Opisthosoma.



Antennae absent. Eyes simple



Excretory structures – Coxal glands



Respiration by book lungs



Free living or parasites

ex. Scorpion – It is carnivorous (feeding on insects) and has abdominal sting with neurotoxic poison; Sexual dimorphism is indistinct. Mating is after courtship dance. In post mating, the female devours the male. It is viviparous animal and produces dozens of young ones.

Prawn

Crab

Centipede

Spider – web secreted by abdominal glands Ticks and Mites – both ectoparasite on mammals. The disease Scabies (Washerman’s disease) is caused by mites (Sarcoptes). The tick is transmitting agent for fever like Colorado Tick fever, Typhus fever and Rocky mountain spotted fever etc. 4.

Limulus

Subphylum MANDIBULATA : mandibles present, includes 4 – classes A.

CLASS CRUSTACEA : Crusta – a hard covering of exoskeleton on cephalothorax,

* For NEET, only salient features- up to Phylum level, are to be studied.

Peripatus Fig. 4.13

128

BIOLOGY called Carapace 

Aquatic and respiration through gills



Number of legs variable (generally 5- pairs)



Antennae 2- pairs



Excretory organs- Green glands (present at the base of antenna, hence also called Antennal glands).



Compound eyes present



Development mostly indirect



Various types of larvae present in the group, like Nauplius (First and the most common larva), Zoea, Megalopa, Phyllosoma and Alima etc.

ex. Palaemon (Prawn) - Nauplius and Metanauplius larva, Astacus (Cray fish) - Larva absent, Cancer (Crab) - Zoea and Megalopa larva, Eupagarus(Hermit crab),Squilla Alima larva, Sacculina (parasite on crab) - Nauplius, Kentrogen and Cypris larva, Cyclops (Secondary host for Guinea worm) - Nauplius larva, Daphnia (Water flea), Shrimp, Woodlice etc. B.

CLASS CHILOPODA : 

Commonly called Centipedes



1- pair of legs per segment



Body differentiated into head and abdomen (Thorax absent)



Metameric segmentation prominent



Eyes simple



Carnivorous and poisonous



Development direct

ex. Scolopendra C.

CLASS DIPLOPODA : 

Commonly called Millipedes



2- pairs of legs per segment



Body differentiated into head , thorax and abdomen



Eyes absent



Herbivorous and non- poisonous



Development direct

ex. Julus D.

CLASS INSECTA (Hexapoda) : 

Study of insects is called Entomology



Body divisible into head , thorax and abdomen



Antennae 1- pair



Compound eyes present



Wings present or absent . If present then 1- pair or 2- pairs



Legs 3- pairs, so called Hexapods



Blood pigment absent (Haemocyanin is present in other arthropods)



Respiration through tracheal tubes



Excretion through Malpighian tubules



Development direct or indirect, if indirect larvae- Caterpillar, Maggot, Grub etc.

ex. Butterfly, housefly, honey bee, wasp, louse , termite, moth, mosquito, dragon fly,Bed

ANIMAL KINGDOM (PART-I & II)

129

bug, Flea, Cicada, Silverfish ((Lepisma) and Chironomous fly etc. Cicada - The males produce louder and shrill sound, audible from kilometers away. Embryonic development takes upto 17 years in completion and hence, is commonly called “Seventeen-years-locust”. A valley in Kerala is called ‘Silent Valley’ because of the absence of this insect. (According to present classification, Insecta, Chilopoda and Diplopoda have been included in subphylum Uniramia, and Crustacea has been raised from class to subphylum level). MOUTH PARTS IN INSECTS : 1.

SPONGING TYPE – e.g. House fly (Mandibles absent)

2.

SIPHONING TYPE- e.g. Butterflies and moths (Mandibles absent)

3.

CUTTING present)

4.

CHEWING AND LAPPING TYPE- e.g. Honey bee

AND CHEWING TYPE-

e.g. Cockroach, grasshopper, termites, ants etc.(Mandibles

5.

PIERCING AND SUCKING TYPE- e.g. Female Mosquitoes, louse, flea and bed bug. In male mosquitoes the mouth parts are sucking type only, by which they feed on flower nectar. METAMORPHOSIS IN INSECTS : 1. AMETABOLA insects – metamorphosis absent. The young ones resemble adult Eggs  → Young  → Adult ex. Lepisma (Silver fish) 2. PAUROMETABOLA insects - gradual metamorphosis Eggs  → Nymph  → Adult ex. Cockroach , Grasshopper, Locusts etc. 3. HEMIMETABOLA insects – incomplete metamorphosis. Habitat of young ones is different from adults. Eggs  → Naiads  → Adult ex. Dragon flies (Naiads aquatic but adults aerial) 4. HOLOMETABOLA insects – complete metamorphosis Eggs  → Larva  → Pupa  → Adult ex. House flies, Butterflies, Mosquitoes etc. The larvae in house flies, Butterflies and Mosquitoes are respectively Maggot, Caterpillar and Wriggler. 5. HYPERMETABOLA insects – various forms of larvae Eggs  → Larva(1)  → Larva(2)  → –  → Pupa  → Adult ex. Blister beetle

Check Point 1. What are respiratory and excretory structures in the followings (i) Crab (ii) Mosquito (iii) Nereis (iv) Spider (v) Starfish (vi) Liver fluke (vii) Pila (viii) Ascaris

PHYLUM MOLLUSCA              

Molluscus – soft bodied Term Mollusca – by Johnston Study of molluscs – Malacology Study of molluscan shells – Conchology IInd largest phylum of animal kingdom. This phylum includes squid which is the largest and the most intelligent invertebrate. Aquatic or terrestrial Triploblastic , bilaterally symmetrical and eucoelomate(Schizocoelic coelom) Body unsegmented and differentiated into Head, visceral mass and foot Visceral mass covered with a fleshy flap called Mantle or Pallium Skeleton of shells or plates of CaCO3 Excretion by Metanephridia or Organ of Bojanus Respiration by gills or ctenidia in aquatic forms and by pulmonary sac in terrestrial forms Blood vascular system Open or Close type, Blood pigment –Haemocyanin; Heart myogenic Locomotory structure – foot (or arms - modified from foot)

* For NEET, only salient features- up to Phylum level, are to be studied.

Pelia

Pearl Oyster Fig. 4.14 :

130

BIOLOGY  

Octopus

Nervous system – annelidan type Mostly dioecious forms; development indirect/direct. Examples : Pila (apple snail) Unio, Pinctada (pearl oyster), Octopus (devil fish), Loligo (squid), Sepia (cuttle fish), Aplysia (sea hare), Dentalium (tusk shell),Chaetopleura (chiton)

*CLASSIFICATION : 6- classes 1. Class Monoplacophora :  Single exoskeleton plate  All marine 

Body segmented (Exceptional case)



Eyes and tentacles absent

ex. Neopilina galaethea – a connecting link between annelids and molluscs, and an important Living Fossil 2.

Class Amphineura (Polyplacophora) : 

Two pairs of ventral nerve cords giving a ladder shaped appearance to the nervous system



All marine



Many exoskeleton plates



Head well differentiated



Development indirect, larva – Trochophore

Sepia

Unio Fig. 4.15

ex. Chiton – 8- exoskeleton plates 3.

Class Gastropoda : 

Foot on stomach



Head well differentiated



Eyes and tentacles well developed



Shell coiled and adult-body asymmetrical



Visceral mass coiled showing Torsion



Marine, fresh water or terrestrial forms



Development indirect. Larva – Trochophore, or Veliger

ex. Pila (Apple snail) – a fresh water snail ; Helix (Garden snail) ; Aplysia (Sea hare) – shell absent Limax (Slug) – shell absent; Patella, Doris (sea lemon), Planorbis (Secondary host of Fasciola hepatica) 4.

Class Pelecypoda or Bivalvia : 

Double (Two) shell plates



Fresh water or marine forms



Head, eyes and tentacles not differentiated



Development indirect. Larva – Glochidium

ex. Unio , Mytilus , Clam , Teredo (Ship worm), Oysters – Indian pearl oyster ––Pinctada vulgaris , Solen (razor shell). Pearl is secreted by the shell glands present in the mantle. The pearl industry is the oldest Industry of Japan 5.

Class Scaphopoda : 

Foot – boat shaped



All marine



Larva – Trochophore

ex. Dentalium (Elephant tusk shell)

ANIMAL KINGDOM (PART-I & II) 6.

131

Class Cephalopoda : 

Foot onto head



Foot modified into arms and siphon



Shell internal or absent



Eyes well developed and resemble vertebrate- eyes



Blood vascular system closed type



Development direct (Larval stage lacking)

ex. Octopus (Devil fish) – 8 arms present and shell absent ; Sepia (Cuttle fish) – 10 arms (2 long and 8 short ), shell internal called ‘cuttle bone’; Loligo (Squid) – 10 arms- the largest invertebrate ; Nautilus – has external ornamental shell Octopus, Sepia and Loligo secrete blue –black ink to defend from predator. Sepia and Loligo also show jet-propulsion movement for locomotion.

PHYLUM ECHINODERMATA              

Spiny- skinned animals (Echino- spines, derma- skin) Exclusively marine Endoskeleton mesodermal- consisting of ossicles and spicules Symmetry in adults - Radial, generally pentamerous; in larvae-bilateral. Body unsegmented Eucoelomate. Coelom- Enterocoel (a chordate character) Locomotory structures- tube feet Respiration – by gills or branchiae, tube feet and respiratory tree Excretory system absent. Excretion by wandering amoebocytes Blood vascular system- called Haemal system, reduced and Open type Water vascular system or Ambulacral system present and helps in locomotion. The opening of the system is called Madreporite Cephalization absent and brain is not differentiated Dioecious but sexual dimorphism absent Fertilization external in water. Development indirect. Larvae bilaterally symmetrical Example : Asterias (star fish), Echinus (Sea urchin), Antedon (Sea lily), Ophiura (brittle star), Sea cucumber. Check Point

Fig. 4.16 :

Asterias

Ophiura

Echinus

*CLASSIFICATION : 5- classes (suffix – idea) - The Extinct classes have not been included. 1. CLASS ASTEROIDEA : e.g. Asterias (Star fish or Sea star)  Pentamerous symmetry  Mouth on oral or ventral side. Anal opening on aboral or dorsal side  Madreporite dorsal  Pedicellariae present and remove dirt particles from the body surface  Digestion out side body and stomach revertible  Two types of larvae. I- Bipinnaria and II- Brachiolaria 2. CLASS OPHIUROIDEA : e.g. Ophiothrix (Brittle star) * For NEET, only salient features- up to Phylum level, are to be studied.

1. To which phyla these terms/ names are associated? (i) Comb-jellies (ii) True worms (iii) Tornaria (iv) Eutely (v) Parapodia (vi) Aristotle’s Lantern (vii) Holometabola (viii) Corals

132

BIOLOGY

3.

4.

5.

Fig. 4.17 : Balanoglossus

 Mouth and madreporite both ventral  Anal opening absent  Arms distinct from the central disc  Show Autotomy of arms, so called Brittle stars  Larva – Pluteus CLASS ECHINOIDEA : e.g. Echinus (Sea urchin), Clypeaster (sand dollar)  Locomotion by movable spines (Arms absent)  Jaw apparatus called Aristotle’s Lantern  Larva- Echinopluteus CLASS HOLOTHUROIDEA : e.g. Holothuria or Cucumaria (Sea cucumber)  Arms absent , but presence of 5- tentacles show pentamerous symmetry  Respiratory tree for respiration  Autotomy by Evisceration (Removal of visceral organs - alimentary canal)  Larva – Auricularia CLASS CRINOIDEA : e.g. Antedon (Sea lily or Feather star)  Mostly sessile , so mouth aboral or dorsal  Water vascular system and Madreporite absent  5- arms, each divided into two branches- just like lily flower  Larva – Pentacrinoid or Doliolaria

ANIMAL KINGDOM (PART-I & II)

133

PHYLUM HEMICHORDATA While going through the chapter pay special attention to the following – Terms and definitions – 1. Neoteny 3. Ophidology 5. Cleidoic (eggs) 7. Ornithology 9. Catadromous (fishes)

2. 4. 6. 8.

Homeotherm Ratitae Amniota Ungulates

Taxonomic Groups – 1. Chiroptera 3. Prototheria 5. Primates 7. Gymnophiona 9. Chondrichthyes

2. 4. 6. 8.

Impennae Lacertilia Cotylosauria Perissodactyla

Animals / Larvae– 1. Sphenodon 3. Phrynosoma 5. Latimaria 7. Herdmania

2. 4. 6.

Platypus Axolotl larva Chameleon

2. 4. 6.

Lateral line organ Pineal eye Remiges

Structures – 1. Preen gland 3. Wish bone 5. Blubber

Previously placed in phylum Chordata, but now shifted to Non- chordata. The structure previously thought to be a notochord is now known to be a buccal diverticulum- an ectodermal structure. 2-classes – Nerve cord Notochord 1. Enteropneusta - ex. Balanoglossus 2. Pterobranchia - ex. Rhabdopleura (Sessile and colonial) Balanoglossus (Acorn worm or Tongue worm) – Post-anal part  It is a connecting link between Non-Chordata and Chordata Gill slits  Its body is divisible into 3- regions, i.e. Proboscis, Collar and Trunk Typical Chordate  Coelom – Enterocoel  Nervous system dorsal and tubular – a chordate character  Pharyngeal gill- slits present – also a chordate character  Development indirect. Larva – Tornaria.

Part-II : Animal Kingdom

Amphioxus

PHYLUM CHORDATA     

Presence of notochord at some stage of life cycle Presence of dorsal tubular nervous system Presence of pharyngeal gill slits at some stage of life cycle Endostyle or thyroid gland present Eyes develop from nervous epithelium and not skin – epithelium Phylum Chordata is divided into 3- subphyla 1. Cephalochordata 2. Urochordata 3. Vertebrata

Ascidia Fig. 4.18

134

BIOLOGY Cephalochordates and Urochordates are called Protochordates or Acraniates, while Vertebrates are also called Craniates.

Subphylum Cephalochordata Notochord extends into cephalic or head region All marine Excretion by protonephridia (having Solenocytes) Pharyngeal gill slits present in adults Coelom - Enterocoel Development mostly direct Amphioxus represents all the 3-chordate characters in adult-stage. The notochord in this animal extends from head to tail. e.g. Branchiostoma or Amphioxus (Lancelet)

Salpa

ot .c om

      

Subphylum Urochordata or Tunicata

og

bl

y.

em

Doliolum

Outer covering of Tunicin- a type of cellulose, secreted in the presence of Vanadium All marine Blood vascular system – Open type Many forms sessile – ONLY CHORDATES WHICH CAN BE SESSILE Coelom secondarily absent Excretory system lacking Unisexual or bisexual forms Asexual reproduction by budding in many forms Development direct or indirect Some forms show Neoteny (Retention of larval characters in adults) and Alternation of generation It includes three classes o Ascidiacea – Sessile tunicates, solitary or colonial. ex. : Herdmania (sea squirt) – Its tadpole larva shows retrogressive metamorphosis. o Thaliacea – Pelagic tunicates, reproduce asexually by budding. ex. : Salpa and Doliolum. o Larvacea – Transparent and free floating, adults shows neoteny, and have two gill-slits only. ex. : Oikopleura.

sp

         

ht tp

s:

//n

ee tm

Fig. 4.19

ed

Petromyzon

ic

al

ac

ad



Subphylum Vertebrata or Craniata  Presence of Brain box or Cranium  Presence of Hepatic portal system  Fins or appendages or limbs paired  Heart ventral in position  Post anal tail present VERTEBRATA is further divided into 2- groups I. Agnatha II. Gnathostomata I. Agnatha (Jawless vertebrates) : 1. Class Ostracodermi :  First vertebrate group (appeared in Ordovician)  Armoured fishes, but all extinct 2. Class Cyclostomata :  All Ectoparasite on fishes  Mouth circular  Gills 6- 14 pairs  Scales on body absent  Fins unpaired (paired appendages absent)  Internal ear with two semi-circular canals e.g. Petromyzon (Lamprey) – gills 7 pairs with 7-pairs of external gill slits, unisexual, development indirect, larva – Ammocoete Myxine (Hag fish) – gills 6- pairs with only 1-pair of external gill slits, bisexual,

ANIMAL KINGDOM (PART-I & II)

135

development direct (Cyclostomes are marine but migrate to fresh water for spawning) II. Gnathostomata : - jawed vertebrates, 2- super classes 1. Superclass Pisces :  Members do not have Pentadactyle (Five- fingered) plan  All aquatic (fishes) 2. Superclass Tetrapoda :  Members have paired pentadactyle limbs  Includes classes Amphibia, Reptilia, Aves and Mammalia

Superclass Pisces           





Includes jawed fishes Study of fishes is called Ichthyology Aquatic, mostly marine Poikilothermic or cold blooded Locomotion by fins Fins of 2- types, paired and unpaired. Paired or lateral fins include Pectoral and Pelvic fins, and unpaired or median fins include dorsal fin, caudal fin, ventral fin and anal fin etc. Exoskeleton of ecto-mesodermal scales Respiration by gills (5-7 pairs) Excretion by mesonephros or opisthonephros kidney Blood vascular system – closed type , with single circulation. Heart 2- chambered with deoxygenated blood only (Venous heart). Cranial nerves 10- pairs. Only internal ear present (for balancing only). Eye lids absent. Internal nostrils absent except in lung –fishes. Lateral line organ having neuromast cells present for detecting water vibrations (Rheoreceptor) Skull monocondylic (one occipital condyle in cranium). Centrum (of vertebrae) amphicoelous. Ribs present. Jaw suspensorium – Hyostylic (lower jaw articulates with Hyomandibular bone of upper jaw.) Unisexual. Fertilization mostly external in water. Development direct. Developmental stages Fish- fry and Fingerlings

CLASSIFICATION : 3- Classes 1. Class PLACODERMI : Armoured jawed fishes with fused bony scales (All forms extinct) 2. Class CHONDRICHTHYES : Subclasses Elasmobranchi and Holocephali 3. Class OSTEICHTHYES or Teleostomi CLASS CHONDRICHTHYES 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12.

Cartilagenous fishes (Endoskeletoncartilaginous) Mostly marine Total 5 % of all fishes Placoid scales present in skin Mouth ventral Gill-slits 5-pairs Operculum or gill cover absent Tail heterocercal (with unequal lobes) Pelvic fins in males form Claspers for transferring sperms into female-body Amongst largest fishes Scroll valve present in intestine Air bladder absent

CLASS OSTEICHTHYES (TELEOSTOMI) 1.

Bony fishes (Bony endoskeleton)

2. 3. 4.

Fresh water or marine forms Total 95 % of all fishes Cycloid, Ganoid or Ctenoid scales present Mouth terminal Gill-slits 4-pairs. Operculum present Tail homocercal (with equal lobes) Claspers absent

5. 6. 7. 8. 9. 10. 11. 12.

Average to small- sized fishes Scroll valve absent Air bladder or swim bladder present (for buoyancy or respiration, as

136

BIOLOGY

13. 14. 15. 16.

Kidney opisthonephros Ampullae of Lorenzini (Thermoreceptor) present in snout region Oviparous, Ovoviviparous or Viviparous Mermaid purse (Egg case) present in oviparous fishes

13. 14.

accessory respiratory organ/lungs, or as a sound producing organ) Kidney mesonephros Ampullae of Lorenzini absent

15. 16.

Oviparous Such egg cases absent

CHONDRICHTHYES e.g. SHARKS – Scoliodon (Dog fish)-a viviparous fish with high smelling power, Pristis (Saw fish) ; Chimaera (King of Herrings or Rat fish) - presence of operculum make them special. RAYS- Trygon (Sting ray), Torpedo (Electric ray) and SCATES – Raja OSTEICHTHYES e.g. Latimeria (Coelacanth fish)- fleshy lobed finned fish (group - Crossopterygi) and a living fossil, considered to be a connecting link between fishes and amphibians, Hippocampus (Sea horse)- shows parental care, Exocoetus (Flying fish), Anabas (Climbing perch) - due to accessory respiratory structure it can survive outside water for several days. Echeneis or Remora (Sucker fish), Gambusia (Minnow) – feeds on mosquito larvae, Labeo rohita (Rohu), Mystus cinghala (Singhara), Clarias batracus (Magur), Eel, Salmon, Acipencer etc.

Check Point 1. Explain why? (i) Scoliodon is called a Dog-fish. (ii) Amphibians are called Poikilothermic. (iii) Trouts are called ‘Anadromous fishes’. (iv) The metamorphosis in tadpole larva of Herdmania is called retrogressive. (v) The fishes have not been included in ‘Tetrapoda’.

Pristis

Catla

Scoliodon

Trygon

Hippocampus

Torpedo

Fig. 4.20

Frog

Ichthyophis Fig. 4.21

Teleostomi also includes LUNG FISHES (Group Dipnoi)- They form connecting link between Fishes and Amphibians. These fishes have gills and lungs both for respiration. The lungs are the modification of air bladder and arise dorsally from oesophagus. The skull is cartilaginous and notochord persists throughout life. Lung fishes have internal nostrils. All are fresh water-forms. There are only three genera of lung fishes in the world, Protopterus- African ; Lepidosiren – American; Neoceratodus –Australian MIGRATION IN FISHES - 2- types 1. Anadromous fishes - During breeding season they migrate from sea to fresh water e.g. Sturgeon (Acipencer) and Salmon (Trout). → Fresh water Sea  2. Catadromous fishes – During breeding season their migration is from fresh water to sea e.g. Anguilla (Eel ). → Sea Fresh water 

ANIMAL KINGDOM (PART-I & II)

137

CLASS AMPHIBIA            

It is the smallest class of vertebrates None marine, but are either terrestrial/amphibious or fresh water forms The body is differentiated into Head, Trunk and Tail (The ‘neck’ is absent in all amphibians). However, in most of the terrestrial or amphibious forms the tail is also absent. Cold blooded or Poikilothermic Undergo aestivation (summer sleep) or hibernation (winter sleep) Alimentary canal has cloacal opening Kidney- Mesonephros type (mostly ureotelic) Respiration- Cutaneous, Branchial or Pulmonary Heart – 3-chambered with sinus venosus, BVS – closed type and the Systemic arch is paired. Both renal and hepatic portal systems well developed. paired Exoskeleton lacking in most of the forms Dioceous (unisexual), fertilization mostly external Oviparous, extra-embryonic membranes absent. Examples : Frog ((Rana tigrina), Toads ((Bufo), Tree frog ((Hyla) Salamander and Ichthyophis (limb less amphibian)

*CLASSIFICATION – 2-subclasses Sub Class 1 - Stegocephalia : All extinct forms. Commonly called Stem-amphibians (Labyrinthodonts). They had dermal bony plates, and larger teeth. Sub Class 2 - Lissamphibia : Dermal bony plates absent and teeth simpler and smaller. The living forms are represented by 3-orders. 1. Order APODA (GYMNOPHIONA): (Gr., Gymnos – naked)  Legs absent, so called limbless- amphibians  Tail vestigial or reduced  Fossorial (Burrowing) with vestigial eyes.  Exoskeleton consists of scales embedded in the skin  Copulatory organ present , so fertilization internal ex. Uraeotyphlus (Blind worm) and Ichthyophis – both show parental care 2. Order URODELA (CAUDATA) : (L., Cauda – tail)  Tail well developed  Legs present and equal –sized  Gills persist in adults for respiration  Exoskeleton lacking  Copulatory organ absent and fertilization external ex. Ambyostoma (Salamander)- larva called Axolotl shows neoteny (Retention of larval characters in adults) and Paedogenesis (reproduce in larval stages) in the deficiency of iodine; Necturus (Mud puppy), Siren (Mud eel), Triturus (Newt), Amphiuma (Congo eel), Proteus (Blind Salamander) 3. Order ANURA (SALIENTIA) : (L., Saliens – Leaping)  Limbs present, but hind limbs longer than fore limbs, for leaping.  Webbed –toes in hind limbs  Tail absent in adults but present in larval stages  Gills absent in adults  Fertilization external ex. Rana tigrina (Indian Bull frog), R. pipiens (Leopard frog), Bufo (Toad), Alytes (Mid-wife toad)- shows parental care, Hyla (Tree frog) and Rhacophorus (Flying frog), Pipa (Surinam Toad), Bombinator (Fire bellied Toad), Xenopus.

* For NEET, only salient features, up to class level, are to be studied.

Salamander

Toad Fig. 4.22

Check Point 1. What are common names of the followings? Herdmania, Amphioxus, Exocoetus, Anabas, Hippocampus, Myxine, Uraeotyphlus, Rhacophorus, Alytes, Hyla, Rana tigrina, Petromyzon, Chelone, Hemidactylus, Sphenodon and Ornithorhyncus.

138

BIOLOGY

CLASS REPTILIA   

Study of reptiles is called Herpetology Study of lizards is called Saurology Study of snakes is called Ophidology or serpentology

General characters      

   

Poikilothermic or cold- blooded True land or terrestrial vertebrates Exoskeleton consists of scales Respiration pulmonary Kidney metanephros Heart incompletely 4- chambered (Completely 4- chambered in Crocodiles and Alligators). Systemic arch paired. Both right and left systemic arches are communicated through Formen of Panizzae. Alimentary canal opens through cloaca Cranial nerves 12- pairs, Olfactory structure – Jacobson’s organ, Columella auris present in ear. Lizards have external , middle and internal ear but snakes have only internal ear Fertilization internal, oviparous having Cleidoic (shelled or box like) eggs Extra embryonic membranes, i.e. Amnion, Chorion and Allantois, present ( group Amniota ). Larvae absent (Development direct) Examples : Tortoise (Testudo), Turtle (Chelone), Garden lizard (Calotes), Wall lizard ( (Hemidactylus ), Girgit (Chameleon), Crocodile, Alligator etc.

Wall Lizard

Krait

Cobra

Chameleon

Calotes

Tortoise

Fig. 4.23

Turtle

Heloderma

Crocodile

*CLASSIFICATION : Basis temporal fossa in the skull 1. ANAPSIDA : Temporal opening/fossa absent Order COTYLOSAURIA (Stem reptiles) – ex. Seymouria (extinct) Order CHELONIA- Teeth absent but jaw plate present, sternum – lacking ex. Testudo (Tortoises – fresh water forms) and Tryonix (Turtles- marine forms) 2. PARAPSIDA : Temporal opening/fossa lateral (one on either side) – all forms extinct 3. SYNAPSIDA : Temporal opening/fossa - one (Fused) on either side; Mammals like reptiles, all extinct forms. ex. Pelycosaurus 4. DIAPSIDA : Temporal opening/fossa two pairs (one pair on either side) * For NEET, only salient features, up to class level, are to be studied.

ANIMAL KINGDOM (PART-I & II) Diapsida is divided into 3- orders A. Rhyncocephalia : ex. Sphenodon punctatum (Tuatara) – A living fossil of New Zealand having 3rd eye (pineal eye) functional in youngs B. Crocodilia : Heart – 4 chambered, teeth – thecodont and muscular diaphragm (all three mammalian characters) present. ex. Crocodile (Narrower snout and fourth mandibular tooth visible), Alligator (Broader and rounded snout - found in North America and China; not in India) and Gavialis (narrow and very long snout) C. Squamata : Divided into two suborders i.e. Lacertilia and Ophidia a. LACERTILIA (lizards) - ex. Hemidactylus (Wall lizard), Draco (Flying lizard), Calotes(Garden lizard), Chameleon (Girgit)- Tongue protruded, Tail prehensile, Asynchronous vision, and colour changing ability present. Heloderma (Gila monster)- only poisonous lizard, found in Mexico. Varanus (Monitor lizardcalled Gho), Uromastix (Spiny- tailed lizard), Mabouiya-a viviparous lizard; Anguis (European) and Ophiosaurus (Indian) - Glass snakes (Both limb-less lizards); and Phrynosoma (Horned toad)- a lizard with hygroscopic skin b. OPHIDIA (Snakes)- Eye lids fixed, Nictitating membrane absent, right lung very long and functional (left lung rudimentary), tympanum absent, urinary bladder also absent, limbs and girdles absent (in Python and Sand boa the hind limbs are present), sternum absent. Poisonous snakes- Naja (Cobra)- neurotoxic poison, Enhydrina and Hydrophis – both sea Snakes and deadly poisonous, Bungarus (Krait), Crotalus (Rattle snake) and Viper- haemotoxic poison, Loreal pit of Pit-Viper is a thermoreceptor. (Viper is a viviparous snake). Non- poisonous snakes : Python (Ajgar), Eryx johni (Sand boa or double headed snake), Natrix (Pond snake), Zamenis or Ptyas (Rat snake or Dhaman), Dendrophis (Tree snake), Typhlops (Blind snake).

139

Bustard

Albatross

CLASS AVES    

Study of birds is called Ornithology Study of birds-nest is called Nidology Bird man of India- Dr. Salim Ali (a famous ornithologist of India) Study of bird’s migration is called Phenology IMPORTANT CHARACTERS:  Homeothermic / Endothermic / Warm- blooded  Body temperature is the highest amongst vertebrates (40- 45°C )  Exoskeleton- ectodermal and consists of Beak, Feathers and Claws  Characteristic feature of birds – presence of feathers  Fore –limbs modified into wings- so bipedal  Body streamlined (faces least air resistance during flight)  Stomach absent but crop and gizzard present  Respiration – Pulmonary ( through Lungs). Lungs inelastic and are supplemented with Air- sacs, Residual air absent  Sound box is called Syrinx and is present at the base of trachea  Kidney – metanephros. Urinary bladder absent. Uricotelic  Heart – 4 chambered. Richest blood amongst vertebrates (with maximum RBC per mm 3 ). Only right systemic arch present  Cranial nerves – 12 –pairs, olfactory lobes reduced. Eyes telescopic with Pecten, attached to choroid. Middle ear with single ear ossicle. Nictitating membrane present in eyes  Uropygeal glands (Preen glands) present in the skin of the tail region – for feather dressing  Gut opens through cloaca

Vulture

Penguin

Owl

Ostrich

Fig. 4.24

140

BIOLOGY In adult females the ovary and oviduct of the right side degenerate. Oviparous – Eggs cleidoic  Extra-embryonic membranes – Amnion, Chorion and Allantois present (group Amniota). Allantois acts as urinary bladder in the embryo. Development is direct.  Bones spongy and pneumatic. Marrow canal absent  Skull monocondylic and vertebrae have heterocoelous centrum  Few vertebrae of thoracic region, all vertebrae of lumber and sacral region and few vertebrae of caudal region fuse to form SYNSACRUM  Posterior Caudal vertebrae fused to form pygostyle  Two clavicles fused with interclavicle to form a fork shaped bone called Furcula or Wish bone or Bone of merry thoughts  Carpals and metacarpals fused to form Carpometacarpus or Wing bone  Tarsals and metatarsals fused to form Tarsometatarsus  Ribs double- headed with uncinate process  Sternum keeled (not flat) for attachment of flight muscles. Example : Pigeon (Columba), Crow (Corvus), ), Parrot ((Psittacula), Peacock ((Pavo cristatus), Penguin ((Aptenodytes), Vulture ((Neophron), Ostrich (Struthio) *CLASSIFICATION : 2 – subclasses 1. Archeo-ornithes : primitive birds – all extinct, ex. Archeopteryx lithographica and Archeornis ( (Archeopteryx was discovered from Bavaria (Germany) by Andreas Wagner in lime stone rocks of Jurassic period)  Toothed birds  Sternum flat, furcula absent  Wing bone absent  Feathers present 2. Neo-ornithes : 4- super orders A. Palaeognathae (Ratitae) : Birds with primitive jaws Ratitae group includes all flight- less birds. ex. Ostrich (African), Rhea (American-ostrich), Cassowary and Emu (Australian) and Kiwi (Newzealand) B. Impennae : ex. Penguins ( Antarctica or south- pole bird) Fore-limbs modified into flippers C. Odontognathae : Fish eating toothed birds – all extinct D. Neognathae : modern birds Arctic tern – migratory bird (Migrates from North to south pole), Humming bird (Smallest one), Swift (Fastest-Flying bird)- hibernates also. Pea fowl ((Pavo Pavo cristatus)order Galliformes; The Male is called Pea cock - our national bird; Koel or Coccoo ( (Eudynamis ) – a brood parasite of crow’s nest, it is male that has melodius sound; Great Indian Bustard – highly endangered bird of Rajasthan, Albatross (Largest bird); Vulture- carnivorous bird, Eagle and Hawk Hawk- both predator birds 

Check Point 1. Fill in the blanks, each with a suitable word. (i) ............................. is a covering of cellulose-like material in Urochordates. (ii) Retention of larval characters in adults is called ......................... (iii) Living jaw-less vertebrates belong to class ........................ (iv) Study of fishes is called .................... (v) Limb-less amphibians belong to order .................... (vi) ...................is the study of birds. (vii) Human belongs to order ..................... (viii) The order ....................contains egg laying mammals. (ix) Flight-less birds belong to group .................... (x) The scientific name of our national bird is ................ (xi) In birds the sound box is called ................. (xii) The tortoises and turtles belong to order ................ (xiii) Study of birds is called ..............

Check Point

1. Name the followings : (i) The Rheoreceptor organ in fishes (ii) The larva of Petromyzon (iii) The chordates that reproduce by budding. (iv) Cutaneous glands in birds for feather dressing (v) The structure modified to lungs in the members of Dipnoi. (vi) A homologue structure of thyroid in protochordates. (vii) Excretory structures in Type of feet Cephalochordates Perching type - adapted for fastening the foot to a branch/perch, ex. Sparrow, Crow (viii) The poisonous lizard of the Raptorial type - adapted for snatching or robbing food, ex. Owl, Vulture, Kite and Eagle etc. world. Wading type - adapted for walking on water surface, ex. Jacana and Heron (ix) The paired fins in fishes. (x) African and American lung Cursorial type - adapted for running, ex. Ostrich, Great Indian Bustard, Rhea and fishes. Emu etc. (xi) The group that includes Scantorial type - adapted for climbing, ex Wood pecker and Parrot Reptiles, Birds and Mammals. (xii) The mammal that has volant Feathers in birds adaptations. (xiii) A living fossil of New Zealand. Epidermal (β-keratin), for insulation and flight. The assemblage of feathers is called (xiv) Subcutaneous fat layer in Plumage. whales. 3-types (xv) The bone formed by the fusion of clavicles and interclavicles in birds. * For NEET, only salient features, up to class level, are to be studied.

ANIMAL KINGDOM (PART-I & II) 1.

141

FLIGHT FEATHERS : also called Quill feathers  Rachis or shaft present  Barbs and barbules interlocked vane rachis

barbs

barbules barb barbules calamus

after shaft calamus

or quill Flight Feather

calamus Down Feather

Filoplume

Fig. 4.25

3- types

2.

3.

A.

Remiges – feathers of wings;

B.

Rectrices – feathers of tail for steering the flight or for break

C.

Coverts- feathers for filling gap between Remiges and Rectrices

DOWN FEATHERS : for insulation in young birds 

Rachis absent



No interlocking of barbs and barbules

FILOPLUMES : minute hair like with unknown function

Platypus

Beaks in Birds 1.

Seed eating beak – Short and stout. ex. : Sparrow

2.

Insect eating beak – Small and delicate. ex. : Swift and Swallow

3.

Fruit eating beak – Sharp, strong and hooked. ex. : Parrot

4.

Fish catching beak – Long, powerful and sharply pointed. ex. : Herons and King Fisher

5.

Mud straining beak – Broad and flat with serrated border (acting as sieve). ex. : Duck

6.

Flower probing beak – Very long, narrow and pointed. ex. : Humming bird

Echidna

CLASS MAMMALIA 

Homeothermic or endothermic or warm blooded



Exoskeleton includes Hairs, Horns, Hoofs, Claws, Nails, Antlers and Scales etc.



Muscular diaphragm between thorax and abdomen



7- cervical vertebrae in general



Amphiplatyon or Acoelous - centrum in vertebrae



Ribs double- headed without uncinate process



Ear ossicles -3, Malleus, Incus and Stapes

Panda

Blue Whale Fig. 4.26

142

BIOLOGY

Sea Lion



Cheek bone or Zygomatic arch present



Sweat glands, Mammary glands and Sebaceous glands present



Kidney – metanephros type, main excretory product – Urea



Respiration pulmonary only



Teeth – thecodont , diphyodont and heterodont



Heart 4- chambered, only left systemic arch present



Cranial nerves -12- pairs. Corpus callosum and Pons varolli present in brain



Amniotes, having extra embryonic membranes- Amnion, Chorion and Allantois



Mostly viviparous, development direct. Placenta generally present (The above characteristics represent Eutherians) Examples : Duck-billed platypus (Ornithorhynchus), Kangaroo (Macropus), Flying fox ( (Pteropus ), Monkey (Macaca), ), Dog (Canis), Cat ((Felis), Horse ((Equus cabalus), Dolphin ( (Delphinus ) Blue whale ((Balaenoptera), Tiger ((Panthera tigris)

Loris

*CLASSIFICATION : 1. Kangaroo

Dolphin

3- subclasses

PROTOTHERIA : order Monotremata 

Egg laying mammals



Uterus and vaginal tube absent



Placenta absent



Pinna absent



Mammary glands, without teats, and functional in both the sexes



Teeth absent in adults, only horny jaws present



Corpus callosum absent but pons varolli present



Cloaca present

Ex. Ornithorhyncus (Duck- billed Platypus)- Truly oviparous and is the only poisonous mammal, having poison gland in thigh. Tachyglossus (Echidna or Spiny ant eater)Ovoviviparous, having yolky eggs. Development internal but placenta absent Pteropus

Fig. 4.27

2.

METATHERIA (Marsupials) : 

Pouched mammals



Uterus and vagina paired



Pinna present



Mammary glands with teats and functional in females only



Teeth monophyodont



Corpus callosum absent



Mainly yolk sac placenta (Vitellochorion placenta) present



Viviparous , birth of premature young ones

ex. Macropus (Kangaroo ), Didelphis (Opossum), Koala (Teddy bear) The adults of Kangaroo and Cow are of the same sizes, but a newly born Kangaroo is bean * For NEET, only salient features, up to class level, are to be studied.

ANIMAL KINGDOM (PART-I & II) sized (~1 g in weight), whereas, the newly born calf weighs ~45 Kg. 3.

EUTHERIA : 

True placental mammals



Uterus and vaginal tube single



Viviparous



Pinna present



Mammary glands with teats and functional in females



Teeth diphyodont



Corpus callosum present



Placenta true or Allantochorion type



Divided into 16-orders

Important orders – A.

Primates – Lemurs, Loris, Tarsiers, Monkeys, Apes and Human

B.

Insectivora (includes smallest mammals) – Hedge hog, Mole (Talpa) and shrews

C.

Lagomorpha – Rabbit (Oryctolagus), ), Hare ((Lepus)

D.

Proboscidia – Elephant

E.

Cetacea – Whales, Dolphins and Porpoises, Blue whale- the largest mammal but without teeth, and feeds on planktons; its subcutaneous fat is called blubber and its jaw plate called Baleen; Sperm whale or toothed whale - feeds of fishes. Ambergris is obtained from its intestine; Dolphins –very intelligent and have echolocation system, Porpoises

F.

Carnivora – Terrestrial ((Fissipedia) - Dog, Tiger, Lion, Cat; Aquatic ((Pinnipedia) Seal , Walrus and Sea Lion.

G.

Sirenia – Sea cows (gp. Manatee)- have 6-9 neck vertebrae

H.

Artiodactyla – even-toed (2 or 4 toes) ungulates or hoofed animals with 4-chambered stomach. Horns generally present. ex. Cows, Buffaloes, Sheep, Deer, Antilope, Goat, Camel, Pig, Giraffe and Hippopotamus etc. (except Pig, all are cud-chewing or ruminants).

I.

Perissodactyla – odd- toed (1 or 3 toes) ungulates or hoofed animals with simple stomach and without horns. ex. Rhino, Horse, Zebra and Ass etc.

J.

Chiroptera – Bats , also have echolocation system (Fruit eating flying foxes and insectivorus bats)

K.

Rodentia – The largest order of mammals including Rats, Squirrel, Guinea pig, Porcupine.

143

144

BIOLOGY

EXERCISE - 1 | NCERT BASED QUESTIONS 1.

2.

3.

4.

5.

6.

7.

8.

9.

The members of following phylum represent cellular level of organization (1) Cnidaria (2) Porifera (3) Protozoa (4) Both (1) and (2) Mark the incorrect statement for the phyla, Platyhelminthes to Echinodermata. (1) All groups represent organ/organ – system level of organization (2) All are triploblastic (3) All are bilaterally symmetrical (4) None of these When any plane passing through the central axis of the body divides the organism into two identical halves, the organism is called (1) Radially symmetrical (2) Bilaterally symmetrical (3) Asymmetrical (4) Metamerically segmented In Platyhelminthes (1) The embryonic layers, ectoderm and endoderm, are separated by mesoglea (2) The body is asymmentrical (3) There is tissue level of organization (4) The body cavity is absent The organisms belonging to following phylum are (true) coelomate (1) Arthropoda (2) Aschelminthes (3) Ctenophora (4) Platyhelminthes Which of the following is a fresh water sponge? (1) Sycon (2) Euspongia (3) Spongilla (4) Pleurobrachia Comb jellies belong to (1) Porifera (2) Cnidaria (3) Ctenophora (4) Corals The members of the following phylum are mostly marine and asymmetrical (1) Ctenophora (2) Coelenterata (3) Porifera (4) Echinodermata Given are the four matches of phyla with their characteristic cells A. Coelenterata - Nematocytes B. Porifera - Choanocytes C. Ctenophora - Solenocytes D. Platyhelminthes - Nephrocytes

10.

11.

12.

13.

14.

15.

16.

17.

18.

Mark the option that has both correct matches (1) A, B (2) B, C (3) C, D (4) B, D Which of the following is commonly called ‘Pearl oyster’ (1) Limulus (2) Pinctada (3) Dentalium (4) Chaetoplenura Following organism is triploblastic, bilaterally symmetrical and marine, and respires through gills (1) Echinus (2) Hirudinaria (3) Balanoglossus (4) Physalia The phenomenon of metagenesis occur in (1) Taenia (2) Aurelia (3) Obelia (4) Musca Which of the following organism is correctly matched with its common name ? (1) Aurelia -comb jelly (2) Adamsia -sea anemone (3) Ancylostoma - pin worm (4) Aplysia - sea mouse The members of following phylum are exclusively marine, radially symmetrical and diploblastic (1) Porifera (2) Echinodermata (3) Ctenophora (4) Hemichordata Given below are four statements regarding Aschelminthes A. They are bilaterally symmetrical and triploblastic B. They are dioecious C. All are plants or animals’ parasites D. They are acoelomate Mark the option that has both the correct statements (1) A, B (2) A, C (3) B, C (4) B, D Which statement regarding Nereis is wrong ? (1) It has nephridium for excretion (2) It is metamerically segmented (3) It is monoecious (4) It has parapodia for swimming In chordates the notochord is (1) Mesodermal and dorsal to nerve cord (2) Endodermal and dorsal to nerve cord (3) Mesodermal and ventral to nerve cord (4) Endodermal and ventral to nerve cord Which set has the two members of the same phylum ? (1) Cuttle fish and jelly fish (2) Tape worm and earthworm (3) Dog fish and dolphin (4) Sea mouse and sea lion

ANIMAL KINGDOM (PART-I & II) 19.

20.

21.

22.

23.

24.

25.

26.

27.

Following is an oviparous mammal (1) Delphinus (2) Ornithorhynchus (3) Macropus (4) Elephas Which of the following feature of bony fish is missing in cartilaginous fishes (1) Operculum (2) Placoid scales (3) Poekilothermic (4) Paired fins Mark the correct match of the animal and its common name (1) Trygon – dog fish (2) Ascidia – lancelet (3) Pterophyllum – flying fish (4) Myxine – hagfish Which of the following is a limbless amphibian (1) Salamander (2) Ichthyophis (3) Pristis (4) Cucumaria Chelone is commonly known as (1) Garden lizard (2) Tortoise (3) Flying lizard (4) Turtle Which of the following is the exclusive feature of the birds (1) 4 – chambered heart (2) Homoeothermic (3) Fore limbs modified into wings (4) Prsence of feathers Sea horse is (1) A marine mammal (2) A marine fish (3) Hippopotamus (4) Antelope Sharks do not have (1) Teeth (2) Claspers (3) Air bladder (4) Ventral mouth Which of the following animal is cold blooded and has 4 - chambered heart (1) Salamander (2) Ornithorhynchus (3) Crocodile (4) Calotes

145 28.

29.

30.

31.

32.

33.

34.

35.

36.

The following group is not a subphylum of Chordata (1) Urochordata (2) Tetrapoda (3) Cephalochordata (4) Vertebrata Salpa and Doliolum belong to (1) Cephalochordata (2) Hemichordata (3) Tunicata (4) Cyclostomata Lamprey is not a fish since it does not have (1) Closed blood vascular system (2) Fins (3) Body scales (4) Cranium and vertebral column Following chordata is not a vertebrate (1) Branchiostoma (2) Petromyzon (3) Salamander (4) Bufo The scientific name of Ostrich is (1) Neophron (2) Aptenodytes (3) Pavo (4) Struthio The members of which group do not exhibit metamerism (1) Pisces (2) Aves (3) Arthropoda (4) Mollusca The cyclostomes are (1) Marine and non migratory (2) Fresh water form and non migratory (3) Marine and migrate to fresh water for spawning (4) Fresh water form and migrate to sea for spawning Which of the follwing is not a chordate character (1) Presence of paired pharyngeal gill slits (2) Ventral heart (3) Solid and ventral nerve cord (4) Presence of post anal tail Crocodile and penguin are similar to Whale and Dogfish in which one of the following features ? [CBSE Final ‘10] (1) Possess a solid single stranded central nervous system (2) Lay eggs and guard them till they hatch (3) Possess bony skeleton (4) Have gill slits at some stage

146

BIOLOGY

EXERCISE - 2 | Window to Competitive Exams 1.

2.

3.

4.

5.

6.

7.

8.

9.

10.

11.

12.

Besides Annelida and Arthropoda metamerism is found in [CBSE ‘95] (1) Cestoda (2) Acanthocephala (3) Chordata (4) Mollusca Organisms attached to substratum generally possesses [CBSE ‘95] (1) Asymmetrical body (2) Radial symmetry (3) One single opening of digestive canal (4) Cilia on the surface to create water current. Jelly fishes belong to class [CBSE ‘89; RPMT ‘95] (1) Hydrozoa (2) Scyphozoa (3) Anthozoa (4) None of the above. The component unit of compound eye of insects is called [MAHE ‘95] (1) Eyelets (2) Fenestrae (3) Ocelli (4) Ommatidia An insect without mandibles is [EAMCET ‘95] (1) Musca (2) Aphid (3) Anopheles (4) Blatta Pasteurella/Yersinia pestis (causal agent of Bubonic Plague) is transmitted by [BHU ‘80; EAMCET ‘95] (1) Cimex (2) Xenopsylla (3) Pediculus (4) Aedes Which one belongs to the class of sea Hare? [MP ‘95] (1) Sea Cow (2) Snail (3) Sepia (4) Sea Squirt Flame cells are main excretory structures of [CPMT ‘86, ‘98 ; BHU ‘92 ; RPMT ‘95] (1) Coelenterates (2) Platyhelminthes (3) Annelida (4) Echinodermata Which is secondary/intermediate host of Hookworm ? [Bihar ‘95] (1) Bed Bug (2) Sandfly (3) Mosquito (4) None Which one spreads through contaminated food. [EAMCET ‘95] (1) Taenia (2) Schistosoma (3) Ascaris (4) Fasciola Amphioxus belongs to [EAMCET ‘95] (1) Craniata (2) Hemichordata (3) Urochordata (4) Cephalochordata Branch of biology dealing with study of fishes is [Bihar ‘89, ‘95] (1) Fishery (2) Fisheries (3) Ichthyology (4) Piscology

13.

14.

15.

16.

17.

18.

19.

20.

21.

22.

23.

24.

Electric organs occur in [MP ‘95] (1) Sharks (2) Goldfish (3) Porpoises (4) Rays Which one is migratory fish [EAMCET ‘95] (1) Shark (2) Ribbon fish (3) Salmon (4) Carp Shagreen is skin of [EAMCET ‘95] (1) Cod fish (2) Sole fish (3) Shark (4) Whale Frog belongs to order [Orissa ‘95] (1) Apoda (2) Anura (3) Urodela (4) Caudata Marsupial Kangaroo is [HP ‘95] (1) Viviparous (2) Oviparous (3) Ovoviviparous (4) A distinct category Poison glands of snake are modified [EAMCET ‘95] (1) Linguals (2) Sublinguals (3) Maxillaries (4) Parotids Preen gland occurs in [RPMT ‘95] (1) Reptilia (2) Aves (3) Pisces (4) Mammalia True Coelom is cavity between alimentary canal and body wall enclosed by [CBSE ‘96] (1) Ectoderm and endoderm (2) Mesoderm and ectoderm (3) Ectoderm on both sides (4) Mesoderm on both sides Which is universal for sponges ? [CBSE ‘96] (1) Marine (2) Calcareous spicules (3) Radial symmetry (4) High regenerative Power Male and female Cockroaches can be distinguished externally through [CBSE ‘91; Punjab ‘94, ‘97; RPMT ‘95, ‘98; CPMT ‘96] (1) Anal styles in male (2) Anal cerci in Male (3) Anal style and antennae in females (4) Both (2) and (3) Which is unrelated [RPMT ‘96] (1) Sea Cucumber (2) Sea Star (3) Sea Urchin (4) Sea Squid Which ones possess larval stages? [DPMT ‘96] (1) Cockroach and Housefly (2) Housefly and Butterfly (3) Cockroach and Honey Bee (4) Grasshopper and Dragonfly.

ANIMAL KINGDOM (PART-I & II) 25.

26.

27.

28.

29.

30.

31.

32.

33.

34.

35.

36.

The infective stage of Ascaris is [CPMT ‘94, ‘96] (1) Fertilized egg (2) Embryonated egg (3) Rhabditoid larva (4) Adult Ascaris Which is an exclusive chordate character (1) True coelom [EAMCET ‘96] (2) Pharyngeal gill slits (3) Bilateral symmetry (4) Triploblastic Lateral line system occurs in [BHU ‘96] (1) Star fish (2) Jelly fish (3) Dog fish (4) All the above Flying Frog is [Bihar ‘96] (1) Rhacophorus (2) Hyla (3) Pipa (4) Alytes One of the following is not a trait of prototherians [RPMT ‘96] (1) Egg laying (2) Absence of teats over mammary glands (3) Absence of corpus callosum (4) Presence of testes outside the abdominal cavity Which one is not a snake ? [RPMT ‘96] (1) Blind snake (2) Glass snake (3) Rattle snake (4) Viper Living fossil lizard of New Zealand (Sphenodon) belongs to [CPMT ‘96] (1) Rhyncocephalia (2) Squamata (3) Chelonia (4) Crocodilia Which one is not a specific trait of birds (Aves)? [RPMT ‘96] (1) Bipedal locomotion (2) Toothless beak (3) Wings (4) Feathers. Coelom produced by splitting of mesoderm is [CPMT ‘97] (1) Hydrocoel (2) Enterocoel (3) Schizocoel (4) Pseudocoel A sponge harmful to oyster industry is [BHU ‘84; AFMC ‘97] (1) Spongilla (2) Euspongia (3) Hyalonema (4) Cliona Which is not a member of class insecta [CPMT ‘91; AFMC ‘96; KCET ‘97] (1) Musca (2) Cockroach (3) Louse (4) Spider Structure common to Housefly and Cockroach is [CPMT ‘97] (1) Chitinous exoskeleton (2) Two pairs of wings (3) Filamentous antennae (4) Sponging mouth parts

147 37.

38.

39.

40.

41.

42.

43.

44.

45.

46.

47.

48.

49.

50.

Dengue fever is spread by [AFMC ‘97] (1) Anopheles (2) Aedes (3) Culex (4) Musca Which is absent in arthropoda ? [JIPMER ‘97] (1) Compound eye (2) Chitinous exoskeleton (3) Closed blood vascular system (4) Malpighian tubules Mature larva of Housefly is [CPMT ‘97] (1) Caterpillar (2) Wriggler (3) Grub (4) Maggot. On the basis of Metamorphosis, Butterfly, Housefly and Mosquito are [CPMT ‘97] (1) Ametabola (2) Holometabola (3) Hemimetabola (4) Paurometabola The animal which does not show any larval stage is [CMPT ‘83 ; MP ‘88 ; Punjab ‘97] (1) Pheretima posthuma (2) Asterias (3) Musca domestica (4) Butterfly Which one is a link between chordates and nonchordates? [CET Chd ‘97] (1) Tadpole larva (2) Sphenodon (3) Balanoglossus (4) Petromyzon Extinct bird, Dodo, belonged to [CET Chd ‘97] (1) Australia (2) India (3) Indonesia (4) Mauritius Limulus belongs to group [BHU ‘98] (1) Insecta (2) Crustacea (3) Merostomata (4) Onychophora Yellow fever is transmitted by [BHU ‘92 ; MP ‘98] (1) Culex (2) Aedes (3) Anopheles (4) Bed Bug. Millipede (Julus) and Centipede (Scolopendra) are both included under [RPMT ‘98] (1) Arachnida (2) Myriapoda (3) Scaphopoda (4) Pelecypoda Isinglass (gelatine-like substance) is obtained from [EAMCET ‘95; MP ‘98] (1) Air bladder of fishes (2) Scales of fishes (3) Liver of Frog (4) Cartilage of shark Which is viviparous [JIPMER ‘86, ‘98] (1) Bony Fish (2) Shark (3) Lung Fish (4) Frog Reproduction in larval stage is known as [BHU ‘98] (1) Paedogenesis (2) Parthenogenesis (3) Neoteny (4) None of the above Dicondylic skull with 10-pairs of cranial nerves occur in [RPMT ‘98] (1) Pisces (2) Amphibia (3) Reptilia (4) Mammalia

148 51.

52.

53.

54.

55.

56.

57.

58.

59.

60.

61.

62.

63.

64.

BIOLOGY Renal portal system is absent in [BHU ‘98] (1) Amphibians (2) Reptiles (3) Birds (4) Both (1) and (2) Sense organs of Aurelia are [AIIMS ‘99] (1) Tentilla (2) Tentaculocyst (3) Nematocyst (4) Otolith Statocysts are sense organs of [EAMCET ‘99] (1) Paramecium (2) Ascaris (3) Medusa of Obelia (4) Taenia solium Sponge structure corresponding to mouth of other animals is [BHU ‘99] (1) Incurrent canal (2) Ostium (3) Osculum (4) Excurrent canal An enterocoelomate invertebrate group is [EAMCET ‘99] (1) Annelida (2) Echinodermata (3) Arthropoda (4) Mollusca Arthropoda is characterized by [JK ‘99] (1) Triploblastic, bilateral symmetry and abdominal appendages (2) Bilateral symmetry and pair of wings (3) Acoelomate and radial symmetry (4) Exoskeleton, metmeric segmentation and jointed appendages. Enterobius infection occurs through [Punjab ‘99] (1) Mosquito (2) Contamination (3) Inoculation (4) Piercing Closed circulatory system occurs in [MAHE ‘99] (1) Earthworm (2) Cockroach (3) Grasshopper (4) Pila Which one is not deuterostome group [AFMC ‘99] (1) Chordata (2) Cephalochordata (3) Annelida (4) Echinodermata Annelida is advanced over Nematoda in having (1) Closed circulation [Punjab ‘99] (2) Metameric segmentation (3) True coelom (4) All the above The Group where adults are degenerated while larvae are well developed is [EAMCET ‘99] (1) Tunicata (2) Agnatha (3) Amphibia (4) Cephalochordata Vestigial hind limbs occur in [EAMCET ‘83, ‘99] (1) Krait (2) Russel’s Viper (3) Python (4) Cobra The Bull Frog of India is [CBSE ‘92; KCET ‘98; JIPMER ‘99] (1) Rana tigrina (2) R. sylvatica (3) R. pipiens (4) R. esculenta Skull of bird is [Punjab ‘99] (1) Dicondylic (2) Monocondylic (3) Amphicondylic (4) Tricondylic

65.

66.

67.

68.

69.

70.

71.

72.

73.

74.

75.

76.

77.

Radial symmetry occurs in [CET Chd ‘97, (1) Porifera and Coelenterata AFMC 2000] (2) Coelenterata and Echinodermata (3) Coelenterata and Platyhelminthes (4) Arthropoda and Mollusca Ephyra is young stage/larva of [AFMC 2000] (1) Obelia (2) Sea Anemone (3) Physalia (4) Aurelia Characteristic cells of Hydra are [AMU 2000] (1) Trichocysts (2) Nematocysts (3) Cnidoblasts (4) Sporocysts Deuterostomes are [Kerala 2000] (1) Platyhelminthes (2) Echinoderms (3) Arthropods (4) Annelids The adults are radially symmetrical but larvae exhibit bilateral symmetry in [Punjab ‘98; Bihar 2000] (1) Mollusca (2) Hemichordata (3) Echinodermata (4) Cephalochordata Deuterostomate and enterocoelomate invertebrate is [MP 2000] (1) Pila (2) Ascaris (3) Aphrodite (4) Asterias Echinoderms are headless, brainless and heartless. Yet they are placed at the top of invertebrates because of presence of [MP 2000] (1) Enterocoel (2) Exclusive marine forms (3) High power of regeneration (4) Great power of reproduction Eye of which molluscan group resembles vertebrate eye [CBSE ‘92 ; AFMC 2000] (1) Bivalvia (2) Gastropoda (3) Pelecypoda (4) Cephalopoda Which among the following is a social insect [CPMT 2000] (1) White Ants (2) Locusts (3) Bed Bugs (4) Mosquitoes Antennae are absent in [AMU 2000] (1) Housefly (2) Mosquito (3) Silkworm (4) Tick Which organism resides in lymph nodes ? [AIIMS 2000] (1) Taenia (2) Wuchereria (3) Plasmodium (4) Fasciola Dropping of gravid proglottides by cestodes is [MP 2000] (1) Autophagy (2) Autotomy (3) Apoptosis (4) Apolysis Cercaria stage of Fasciola hepatica leads to (1) Sporocyst (2) Redia [AMU 2000] (3) Miracidium (4) Metacercaria

ANIMAL KINGDOM (PART-I & II) 78.

79.

80.

81.

82.

83.

84.

85.

86.

87.

88.

89.

90.

Which is not characteristic of all chordates [CBSE 2000] (1) Dorsal nerve cord (2) Diaphragm between thorax and abdomen (3) Coelom (4) Pharyngeal gill slits Scoliodon is called Dog Fish because of its [MP 2000] (1) Carnivorous nature (2) Long Mouth (3) Power of smell (4) All of these Surinam Toad is [RPMT 2000] (1) Pipa (2) Alytes (3) Bufo (4) Bombinator Neoteny is found in [RPMT ‘95, Kerala 2000] (1) Axolotl (2) Hyla (3) Salamander (4) Tadpole Which is correct ? [CBSE 2000] (1) Platypus lays eggs (2) Camel has biconcave RBCs (3) Rat has cloaca (4) Bat has feathers Sound box of birds is called [Punjab 2000] (1) Pygostyle (2) Larynx (3) Syrinx (4) Synsacrum National Bird of India is [AIIMS ‘96; RPMT 2000] (1) House sparrow (2) Peacock (3) Hornbill (4) Black Swan Characteristic free swimming larva of coelenterates is [CPMT 2000; BHU’01] (1) Onchosphere (2) Hydrula (3) Planula (4) Amphiblastula Amphiblastula is larva of [AFMC ‘01] (1) Leucosolenia (2) Sycon (3) Both (4) Clathrina Which one is correct pairing [MAHE ‘01] (1) Hydra - Anthozoa (2) Paramecium - Arachnida (3) Plasmodium - Sporozoa (4) Amoeba – Ciliata. Black water fever is caused by [CPMT ‘01] (1) Plasmodium malariae (2) P. ovule (3) P. falciparum (4) P. vivax. Veliger larva occurs in phylum [DPMT ‘01] (1) Mollusca (2) Echinodermata (3) Arthropoda (4) Cnidaria What is characteristic of deuterostomes [DPMT ‘01] (1) Spiral cleavage, blastopore becoming mouth (2) Radial cleavage, blastopore becoming anus (3) Spiral cleavage, blastopore becoming anus (4) Radial cleavage, blastopore becoming mouth

149 91.

92.

93.

94.

95.

96.

97.

98.

99.

100.

101.

102.

103.

Mouth parts of Housefly are [MP ‘87; CPMT ‘93, ‘98; EAMCET ‘95; UA ‘01] (1) Sponging Type (2) Siphoning Type (3) Piercing and sucking (4) Biting and chewing type Which one occurs in molluscs but not in echinodermates [AFMC ‘01] (1) Exoskeleton (2) Tube feet (3) Kidney (4) None of the above Characteristic of class Crustacea is [AIIMS ‘01] (1) Cephalothorax, biramous appendages and gills (2) Head and thorax, book lungs and chitinous exoskeleton (3) Cephalothorax, book lungs and chitinous exoskeleton (4) Head and thorax, biramous appendages and book lungs. An arthropod belonging to onychophora which possesses nephridia is [BHU ‘01] (1) Limulus (2) Peripatus (3) Daphnia (4) Lepisma Common feature amongst Silver Fish, Crab, Cockroach and Honey Bee is [AFMC ‘01] (1) Poison glands (2) Jointed legs (3) Compound eyes (4) Metamorphosis In Cockroach, coelom is [EAMCET ‘01] (1) Schizocoel (2) Enterocoel (3) Pseudocoel (4) Absent Book lungs occur in [DPMT ‘01] (1) Earthworms (2) Insects (3) Arachnids (4) Mammals Ancylostoma infection spreads through (1) Contaminated Food [AFMC ‘01] (2) Bite of mosquito (3) Skin (4) Blood One of the following is pseudocoelomate [DPMT ‘01] (1) Tapeworm (2) Liver fluke (3) Hookworm (4) Jelly fish Ascaris larva is called [CBSE ‘92 ; Bihar ‘01] (1) Cysticercus (2) Rhabditiform (3) Hexacanth (4) Onchosphere. Animals with metameric segmentation, bilateral symmetry and closed circulatory system belong to phylum [AMU ‘01] (1) Annelida (2) Echinodermata (3) Arthropoda (4) Mollusca Elasmobranchs generally lack[Punjab ‘98; Wardha ‘01] (1) Gill slits (2) Operculum (3) Notochord (4) Placoid scales The most Ancient vertebrates are [CPMT ‘01] (1) Ostractoderms (2) Placoderms (3) Cyclostomes (4) Choanichthyes

150 104. Which of the following is a living fossil [HP ‘01] (1) Latimeria (2) Lamprey (3) Shark (4) Eel. 105. An indigenous fish used in biological control is [MP ‘01] (1) Catla (2) Lebistes (3) Gambusia (4) Aplocheilus 106. Venom of Cobra affects [AFMC ‘01] (1) Respiratory system (2) Nervous system (3) Circulatory system (4) Digestive system 107. Midwife Toad is [UA ‘01] (1) Bufo (2) Rana (3) Pipa (4) Alytes 108. A nonpoisonous snake is [DPMT ‘83; RPMT ‘95; BHU ‘96; CPMT ‘01] (1) Viper (2) Python (3) Bungarus (4) Sea snake 109. Amniota includes [DPMT ‘82, ‘85; Punjab 2000; Wardha ‘01] (1) Reptiles and mammals (2) Birds and mammals (3) Reptiles and birds (4) Reptiles, birds and mammals 110. Order insectivora belongs to [KCET ‘01] (1) Mammalia (2) Insecta (3) Arthropoda (4) Echinodermata 111. Sea Cows belongs to [MP ‘01] (1) Sirenia (2) Cetacea (3) Lagomorpha (4) Proboscidia 112. Which one is not a coelenterate ? [MP ‘02] (1) Sea Fan (2) Jelly fish (3) Sea Cucumber (4) Sea Pen 113. Protista contains [Orissa ‘02] (1) Euglena, Dinoflagellates and Yeast (2) Amoeba, Paramaecium, Hydra (3) Euglena, Paramaecium, Mushroom (4) Amoeba, Paramaecium and Dinoflagellates. 114. Common Bath sponge is [CPMT ‘86, ‘93; CBSE ‘95; MP ‘02] (1) Spongilla (2) Euspongia (3) Leucosolenia (4) Sycon 115. Larva like stage of Hydra is [RPMT ‘02] (1) Planula (2) Hydrula (3) Scyphula (4) Olynthus 116. Animal group with pseudocoelom is [Kerala ‘02; CPMT ‘02; DPMT ‘02] (1) Echinoderms (2) Molluses (3) Aschelminthes (4) Annelids 117. Diagnostic feature of insects is [CPMT ‘90 ; CET Chd 2000; MP ‘02] (1) Three pairs of legs

BIOLOGY

118.

119.

120.

121.

122.

123.

124.

125.

126.

127.

128.

129.

(2) A pair of compound eyes (3) Chitinous exoskeleton (4) Segmented body Cray Fish belongs to [BHU ‘98; AMU ‘02] (1) Pisces (2) Mollusca (3) Arthropoda (4) Anthozoa Peripatus is connecting link between [BHU ‘82; CPMT ‘86; Bihar ‘95 ; AFMC ‘02] (1) Annelida and Arthropoda (2) Mollusca and Arthropoda (3) Annelida and Mollusca (4) Coelenterata and Platyhelminthes. Which is an insect [CPMT ‘02] (1) Mite (2) Prawn (3) Moth (4) Scorpion Silver Fish belongs to [DPMT ‘02] (1) Insecta (2) Mollusca (3) Chordata (4) Echinodermata Star Fish belongs to [CBSE ‘92 ; KCET ‘98 ; BHU ‘02] (1) Asteriodea (2) Ophiuroidea (3) Holothuroidea (4) Crinoidea Aristotle’s Lantern occurs in [DMPT ‘83, 02 ; CPMT ‘91 ; BHU ‘98 ; RPMT ‘02] (1) Sea Urchin (2) Asterias (3) Brittle Star (4) Feather Star Acarology is study of [MP ‘02] (1) Coral reefs (2) Mullusca (3) Fossils (4) Ticks and Mites Coelom filled with muscular and connective tissues or botryoidal tissue occurs in [CPMT ‘87, ‘88, ‘91; DPMT ‘02 ; BHU ‘02] (1) Ascaris (2) Nereis (3) Pheretima (4) Hirudo Pseudocoelom develops form [CPMT ‘02] (1) Blastopore lip (2) Archenteron (3) Embryonic mesoderm (4) Blastocoel Syncytial epidermis occurs in [CPMT ‘87, ‘89, ‘90; BHU ‘94, ‘01 ; DPMT ‘99, ‘01; Bihar ‘02 ] (1) Ascaris (2) Hydra (3) Taenia (4) Leucosolenia Bilateral symmetry, blastopore forming mouth and true coelom occur in [Vellore ‘02] (1) Echinodermata (2) Chordata (3) Annelida (4) Platyhelminthes Which one is correct [Orissa ‘02] (1) Flatworms are eucoelomates (2) Fishes are radially symmetrical (3) Birds are poikilothermic (4) Earthworm is metamerically segmented.

ANIMAL KINGDOM (PART-I & II) [MAHE ‘02] 130. Which is true ? (1) Chordates have ventral hollow nerve cord (2) All vertebrates have open circulatory system (3) All chordates are vertebrates (4) All vertebrates are chordates. 131. Notochord occurs in the embryonic stage in [CBSE ‘02] (1) Some chordates (2) All chordates (3) All vertebrates (4) Some vertebrates 132. Animals devoid of respiratory, excretory and circulatory organs are [Haryana ‘93, DPMT 02] (1) Tapeworms (2) Sponges (3) Threadworms (4) Liver Fluke 133. Stenohaline fishes are [MP ‘02] (1) Marine fishes only (2) Those which tolerate narrow range of salinity (3) Those which tolerate wide range of salinity (4) Fresh water fishes only. 134. Which one has a brood pouch for caring of eggs? [AMU ‘02] (1) Anabas (2) Scoliodon (3) Hippocampus (4) Cuttle fish 135. Which one has heterocercal tail [RPMT ‘02] (1) Dipnoi (2) Bony fish (3) Cartilaginous fish (4) All the above 136. Which is vestigial in Python [BHU ‘02] (1) Scales (2) Hind limbs (3) Teeth (4) Nose 137. A limbless amphibian is [CPMT ‘91; BHU ‘95; Kerala ‘02] (1) Hyla (2) Ichthyophis (3) Alytes (4) Bufo 138. Urinary bladder is absent in [AMU ‘02] (1) Amphibians (2) Mammals (3) Lizards (4) Aves 139. Bat, Whale and Human share the following trait [MAHE ‘02] (1) Hair (2) Placenta (3) Nocturnal (4) Position of mammary glands 140. In which set all the animals belong to Mammalia [Orissa ‘02] (1) Lion, Bat, Whale, Ostrich (2) Lion, Penguin, Bat and Hippopotamus (3) Kangaroo, Hippopotamus, Penguin and Whale (4) Kangroo, Bat, Whale and Hippopotamus 141. The character which differentiates mammals from birds is [RPMT ‘02] (1) Seven cervical vertebrae (2) Parental care (3) One aortic arch (4) Metanephric kidney

151 142. Most animals domesticated by humans belong to [BHU ‘02] (1) Carnivora (2) Rodentia (3) Lagomorpha (4) Ungulata 143. Archaeopteryx is connecting link between [BHU ‘98; Kerala 2000, ‘02] (1) Reptiles and birds (2) Reptiles and mammals (3) Fishes and reptiles (4) Chordates and nonchordates 144. Sycon belongs to a group of animals which are best described as [CBSE ‘03] (1) Unicellular or acellular (2) Multicellular without any tissue organization (3) Multicellular with a gastrovascular system (4) Multicellular having tissue organization but no body cavity. 145. Which one of the following is a matching pair of an animal and certain phenomenon it exhibits [CBSE ‘03] (1) Pheretima – Sexual dimorphism (2) Musca – Complete metamorphosis (3) Caraucius – Mimicry (4) Taenia - Polymorphism 146. During its life cycle, Fasciola hepatica (Liver Fluke) infects its intermediate host and primary host at the following larval stages respectively. [CBSE ‘03] (1) Redia and Miracidium (2) Cercaria and Redia (3) Metacercaria and Cercaria (4) Miracidium and Metacercaria 147. Entamoeba differs from Amoeba in not having [BHU ‘05’ AMU ‘05; Orissa ‘05] (1) Nucleus

(2) Pseudopodia

(3) Ectoplasm (4) Contractile vacuole 148. Trochophore larva occurs in [BHU ‘95; ‘05; (1) Annelida and Porifera Orissa ‘05] (2) Coelenterata and Annelida (3) Mollusca and Coelenterata (4) Annelida and Mollusca. 149. From the following statements select the wrong one. [CBSE’05] (1) Prawn has two pairs of antennae (2) Nematocysts are characteristic of the Pylum Cnidaria (3) Millepedes have two pairs of appendages in each segment of the body (4) Animals belonging to Phylum Porifera are exclusively marine

152 150. In contrast to Annelids the Platyhelminths show: [CBSE’05] (1) Absence of body cavity (2) Bilaterial symmetry (3) Radial symmetry (4) Presence of pseudocoel 151. Which of the following unicellular organism has a macronucleus for trophic function and one or more micronuclei for reproduction? [CBSE’05; AMU ‘05] (1) Euglena (2) Amoeba (3) Paramecium (4) Trypanosoma 152. Tube feet is the locomotory organ in [BHU ‘05] (1) star fish (2) jelly fish (3) silver fish (4) scoliodon 153. Flame cells are excretory organ of [BHU ‘05] (1) Planaria (2) Hydra (3) Hydrilla (4) cockroach 154. Which of the statement is false [Kerala ‘05] (1) Male round worm is smaller than female (2) Earth worm are hermaphrodite (3) Echinoderm are protostomous coelomates (4) Human teeth are comparable to scales of shark 155. Ospharidium is meant for [CPMT ‘05] (1) excretion (2) nutrition (3) selection and rejection of food (4) grinding of food 156. Which one of following feature is possessed by crustaceans and not by insects? (1) paired limbs [CPMT ‘05] (2) two pairs of antenna (3) chitinous exoskeleton (4) bilateral symmetry 157. Elephantiasis causing organism belongs to [MAHE ‘05] (1) aschelminthes (2) platyhelminthes (3) cnidaria (4) porifera 158. Trochophore larva is found in [CPMT ‘05] (1) Chiton (2) Nereis (3) Aphrodite (4) All of these 159. Slipper animalcule is [MAHE ‘05] (1) Paramecium (2) Trypanosoma (3) Entamoeba (4) protozoa 160. Symmetry in cnidaria is [Orissa ‘05] (1) radial (2) bilateral (3) pentamarous (4) spherical 161. Leeches are usually [JK ‘05] (1) herbivorous (2) insectivorous (3) carnivorous (4) sanguivorous 162. Excretory organs in Taenia are [JK ‘05] (1) flame cells (2) nephridia (3) nephrons (4) kidneys 163. Body cavity lined by mesoderm is called [JK ‘05] (1) coelenteron (2) pseudocoel (3) coelom (4) blastocoel

BIOLOGY 164. Match the following column I with column Ii and choose the correct combination from the options given [Kerala ‘05] Column I Column II A. earthworm I. Gizzard B. cockroach II. Caecum C. frog III. Clitellum D. rat IV. Cloaca (1) A-I, B-II, C-IV, D-III (2) A-III, B-I, C-IV, D-II (3) A-II, B-I, C-III, D-IV (4) A-III, B-I, C-II, D-IV 165. In which of the following binary fission is not seen? [Orissa ‘05] (1) Plasmodium (2) Amoeba (3) Euglena (4) Paramecium 166. Which one of the following features is common in silverfish, scorpion, dragonfly and prawn? [AIIMS ‘05] (1) Three pairs of legs and segmented body (2) Chitinous cuticle and two pairs of antennae (3) Jointed appendages and chitinous exoskeleton (4) Cephalothorax and tracheae 167. Feeding in sponges takes place through [CPMT ‘05] (1) choanocytes (2) nurse cells (3) ostia (4) osculum 168. Sea fan belongs to [CPMT ‘05] (1) echinodermata (2) crinoidea (3) mollusca (4) coelentrata 169. Which insect is called ‘Horn Beetle’? [CPMT ‘05] (1) Tribolium (2) Corcyra (3) Trogoderma (4) none of these 170. What distinguishes an insect from a crustacean? (1) number of appendages (2) number of eyes (3) presence of wings (4) arrangement of nerve cord 171. Sea anemone belongs to the phylum [BCECE ‘05] (1) porifera (2) echinodermata (3) coelenterata (4) protista 172. Which one incorrect [Orissa ‘05] (1) shell fish - Pisces (2) Silver fish - Arthropoda (3) Cuttle fish - Mollusca (4) Star fish - Echinodermata 173. Enterocoelous coelom is found in [Orissa ‘05] (1) deuterostomia (2) astomia (3) protostomia (4) blastostomia 174. A list of animals is given below. Identify the animals with open circulatory system and choose the correct answer? [Kerala ‘05] (i) ascidia (ii) cockroach (iii) earthworm (iv) prawn (v) silverfish (vi) snail (vii) squid (1) (ii), (iv), (vi) (2) (i), (ii), (iv), (vi) (3) (iii), (iv), (v), (vii) (4) (ii), (iv), (v), (vi)

ANIMAL KINGDOM (PART-I & II) 175. Notochord occurs all through the length of body and throughout life in [EAMCET ‘01; BHU ‘05] (1) Hemichordata (2) Urochordata (3) Cephalochordata (4) Vertebrata 176. An egg laying mammal is [CBSE ‘92, ‘93; KCET ‘98; AIIMS ‘01; JK ‘05] (1) Kangaroo (2) Platypus (3) Koala (4) Whale 177. Which one of the following characters is not typical of the class Mammalia? [CBSE’05] (1) Thecodont dentition (2) Alveolar lungs (3) Ten pairs of cranial nerves (4) Seven cervical vertebrae 178. Match item in column A with those given in column B [Kerala ‘05] Column A Column B A. limbless reptile 1. lamprey B. jawless vertebrate 2. salamander C. amphibian 3. snake D. cartilaginous fish 4. shark E. flightless bird 5. ostrich (1) A-1, B-2, C-3, D-4, E-5 (2) A-2, B-1, C-3, D-4, E-5 (3) A-3, B-1, C-2, D-4, E-5 (4) A-4, B-2, C-3, D-1, E-5 179. A muscular transverse partition in mammals that separates thorax from abdomen is called (1) diaphragm (2) pharynx [JK ‘05] (3) stomach (4) duodenum 180. Zoological name of common Indian Krait is (1) Bungarus coeruleus [Orissa ‘05] (2) Ophiophagus hannah (3) Viper russeli (4) Naja naja 181. Which of the following feature is not common between Newt & Hemidactylus? [CPMT ‘05] (1) body is divisible into head, neck, trunk and tail (2) head with pair of eyes and tympanic membrane (3) trunk has 2 pair of limbs for locomotion (4) heart is 3-chambered 182. Right aortic arch is present in [MAHE ‘05] (1) reptiles only (2) mammals only (3) birds only (4) both birds and mammals 183. Which one of the following features is present at some stage in the life history of all chordates? [CPMT ‘05] (1) blood flowing forward in dorsal blood vessel (2) pharyngeal gill slits (3) a ventral hollow nerve cord (4) heart lying dorsally

153 184. Which of the following respires by gills? [JK ‘05] (1) whale (2) turtle (3) frog (4) prawn 185. Carapace is present on the dorsal surface of [BHU ‘05] (1) elephant (2) tortoise (3) python (4) alligator 186. Exoskeleton is absent in [BHU ‘05] (1) scoliodon (2) frog (3) rabbit (4) fowl 187. Ruminants belongs to order [BHU ‘05] (1) proboscida (2) artiodactyla (3) marsupials (4) edentata 188. Neoteny refers to [Kerala ‘05] (1) develoment of gonads (2) pre-adult animal (3) metamorphosis (4) retention of larval or embryonic trait in the adult body 189. Presence of Carapace can be observed in [AMU ‘05] (1) Hemidactylus (2) Testudo (3) Naja (4) Bufo 190. The following are endothermic vertebrates [AMU ‘05] I. Didelphis II. Delphinus III. Tachyglossus IV. Pteropus Amongst these in which pair, the broad transverse band of nerve tissue connecting internally the two cerebral hemispheres is either poorly developed or absent (1) I and III (2) I and II (3) II and IV (4) III and V 191. Pelagic tunicate which exhibits Neoteny is [EAMCET ‘05] (1) Amblystoma (2) Salpa (3) Oikolpleura (4) Botryllus 192. Which of the below given has a raft like keel, a preen gland and a penis? [EAMCET ‘05] (1) Dromnius (2) Passer (3) Struthio (4) Tinamus 193. Match the following : [EAMCET ‘05] List I List II A. Echidna 1. Ophidia B. Echinus 2. Teleostei C. Echeneis 3. Platyhelminthes D. Echis 4. Echinoidea E. Echinococcus 5. Prototheria (1) A-5, B-1, C-2, D-4, E-3 (2) A-5, B-1, C-3, D-4, E-2 (3) A-5, B-4, C-2, D-3, E-1 (4) A-5, B-4, C-2, D-1, E-3 194. In which one of the following sets of animals do all the four give birth to young ones? [CBSE ‘06] (1) Platypus, Penguin, Bat, Hippopotamus (2) Shrew, Bat, Cat, Kiwi (3) Kangaroo, Hedgehog, Dolphin, , Loris (4) Lion, Bat, Whale, Ostrich

154 195. Annual migration does not occur in the case of [CBSE ‘06] (1) Siberian crane (2) Salamander (3) Arctic tern (4) Salmon 196. All mammals without any exception are characterized by [AIIMS’06] (1) viviparity and biconcave red blood cells (2) extra-abdominal testes and a four chambered heart (3) heterodont teeth and 12 pairs of cranial nerves (4) a muscular diaphragm and milk producing glands 197. A lizard- like member of reptilia is sitting on a tree with its tail coiled around a twig. This animal could be [AIIMS’06] (1) Hemidactylus showing sexual dimorphism (2) Varanus showing mimicry (3) garden lizard (Calotes) showing camouflage (4) Chamaeleon showing protective colouration 198. Animals having a built in thermostat to maintain constant body temperature are known as [BHU’06] (1) biothermic (2) poikilothermic (3) oligothermic (4) homoeothermic 199. Monkey or birds are [HPMT’06] (1) insectivorous (2) frugivorous (3) sanguivorous (4) deterivorous 200. Which of the following is a polygamous palaeognathae member with a syrinx? [JK’06] (1) Archaeopteryx (2) Dromius (3) Rhea (4) Tinamus 201. Which one of the following is a protostomian? [JK’06] (1) Pristis (2) Trichinella (3) Amphioxus (4) Echinus 202. Match the followings [JK’06] Set-I Set-II 1 Latimeria (i) Discontinuous Distribution 2 Zygaena (ii) Remora 3 Echeneis (iii) Aestivation 4 Protopterus (iv) Ureotelic 5 Dipnoi (v) Rhipidistia (1) 1 - (iv), 2 - (v), 3 - (ii), 4 - (i), 5 - (iii) (2) 1 - (v), 2 - (iv), 3 - (ii), 4 - (i), 5 - (iii) (3) 1 - (v), 2 - (iv), 3 - (ii), 4 - (iii), 5 - (i) (4) 1 - (v), 2 - (iv), 3 - (iii), 4 - (ii), 5 - (i) 203. Endostyle is similar to the following in [Orissa’06] (1) parathyroid (2) thymus (3) thyroid (4) thalamus 204. Epidermal scale is the characteristic feature of class reptilia. Which of the following class is without epidermal scale? [Orissa’06] (1) Pisces (2) Aves (3) Mammalia (4) Amphibia

BIOLOGY 205. Mammals have [CPMT’06] (1) dorsal have (2) hollow brain (3) ventral spinal cord (4) ventral brain 206. Totipotent cells of sponges are [CPMT ‘93; ‘06] (1) Thesocytes (2) Archaeocytes (3) Myocytes (4) Chromocytes. 207. The pathogen and the vector of the malarial parasite respectively are [CPMT’06] (1) Plasmodium & Anopheles (2) Trypanosoma & Culex (3) Leishmania & sand fly (4) Wuchereria & Culex 208. Which one of the following has an open circulatory system ? [CBSE ‘06] (1) Periplaneta (2) Hirudinaria (3) Octopus (4) Pheretima 209. Two common characters found in centipede, cockroach, and crab are [CBSE ‘06] (1) Jointed legs and chitinous exoskeleton (2) Green gland and tracheae (3) Book lungs and antennae (4) Compound eyes and anal cerci 210. Biradial symmetry and lack of cnidoblasts are the characteristics of [CBSE ‘06] (1) Ctenoplana and Beroe (2) Aurelia and Paramecium (3) Hydra and starfish (4) Starfish and sea anemone 211. Metameric segmentation is the characteristic of (1) Echinodermata and Annelida [CBSE ‘06] (2) Annelida and Arthropoda (3) Mollusca and Chordata (4) Platyhelminthes and Arthropoda 212. Which one of the following is a matching set of a phylum and its three examples ? [CBSE ‘06] (1) Platyhelminthes-Planaria, Schistosoma, Enterobius (2) Mollusca - Loligo, Teredo, Octopus (3) Porifera - Spongilla, Euplectella, Pennatula (4) Cnidaria - Bonellia, Physalia, Aurelia 213. What is common about Trypanosoma, Noctiluca, Monocystis and Giardia ? [CBSE ‘06] (1) They have flagella (2) They produce spores (3) These are all parasites (4) These are all unicellular protists 214. Which of the following animal can successful reproduce without utilizing the process of meiosis? [KCET’06] (1) Amoeba (2) Hydra (3) tapeworm (4) sycon

ANIMAL KINGDOM (PART-I & II) 215. When children play bare footed in pools of dirty water and flood water, they may suffer from disease like [AIIMS’06] (1) leptospirosis and bilharzia (2) malaria, amoebic dysentery & leptospirosis (3) bilharzia, infective hepatitis and diarrhoea (4) guinea worm inflection, elephantiasis and amoebic dysentery 216. Which one of the following animals is correctly matched with its one characteristic and the taxon? [AIIMS’06] animal Characteristic taxon (1) millipede ventral nerve cord Arachnida (2) duckbill platypus oviparous Mammalia (3) silverfish pectoral & Chordata pelvic fins (4) sea anemone triploblastic cnidaria 217. Polyp phase is absent in [BHU’06] (1) Hydra (2) Aurelia (3) Physalia (4) Obelia 218. Changes that allow the conversion of larva into adult is called [BHU’06] (1) metagenesis (2) alternation (3) metamorphosis (4) metastasis 219. Which of the following cell type is capable of giving rise to other cell types in sponges? [BHU’06] (1) thesocytes (2) pinacocytes (3) cnidocytes (4) archaeocytes 220. In which of the following animals, respiration occurs without any respiratory organ? [BHU’06] (1) frog (2) fish (3) cockroach (4) earthworm 221. The characterstic larva of phylum ‘coelenterata’ is [BHU’06] (1) planula (2) cysticercus (3) rhabdiform (4) wriggler 222. ‘Turbellarians’ are free living [BHU’06] (1) nematodes (2) cestodes (3) flat worms (4) trematodes 223. Among the following the colonial insects are [BHU’06] (1) locusts (2) mosquitoes (3) white ants (4) bed bug 224. In mollusca, eye is present over a stalk called [BHU’06] (1) ostractum (2) operculum (3) ommatophore (4) osphradium 225. Pseudocoelom occurs in [AMU’06] (1) Ascaris (2) Taenia solium (3) Fasciola hepatica (4) Planaria 226. Gemmules thought to the internal bud in sponges (1) sexual reproductive body [HPMT’06] (2) asexual reproductive body (3) collection of spermatocyte (4) collection of egg

155 227. An example for animal with triaxial symmetry (1) Obelia (2) Metridium [JK’06] (3) Cucumaria (4) Pheretima 228. Match the following [JK’06] 1 Euplectella (i) Phytomastigophora 2 Echinoderis (ii) Echinoidea 3 Echinus (iii) Ophidia 4 Echis (iv) Echinodera 5 Euglena (v) Hexactinellida (1) 1 - (v), 2- (iv), 3 - (ii), 4 - (i), 5 - (iii) (2) 1 - (iv), 2- (v), 3 - (ii), 4 - (iii), 5 - (i) (3) 1 - (v), 2- (iv), 3 - (i), 4 - (ii), 5 - (iii) (4) 1 - (v), 2- (iv), 3 - (ii), 4 - (iii), 5 - (i) 229. The following are the features associated with cnidaria [JK’06] (I) radial symmetry (II) presence of gastrovascular cavity (III) animals are in either of the two forms-polyp and medusa or both (IV) alternation of generations in their history Which of the above are true of Metridium? (1) all (2) only (I), (II) and (IV) (3) only (I), (II) (4) only (II) & (III) 230. All triploblastic animal have primarily (1) bilateral symmetrical [Orissa’06] (2) true coelom (3) reproduction with sexual dimorphism (4) regeneration power 231. Which is exclusively marine phylum? [Orissa’06] (1) porifera (2) polychaeta (3) echinodermata (4) mollusca 232. Which of the following classes exhibit polymorphism? [Orissa’06] (1) hydrozoa (2) scyphozoa (3) calcaria (4) polychaeta 233. Gut parasite belongs to class? [Orissa’06] (1) Trematoda (2) cestoda (3) both (1) and (2) (4) None of these 234. Which is incorrect? [Orissa’06] (1) nematocyst- cnidaria (2) colloblast-ctenophora (3) trichocyst-mastigophora (4) choanocyte-porifera 235. Most appropriate word for protozoans is [Orissa’06] (1) cellular (2) unicellular (3) acellular (4) multicellular 236. Platyhelminthes are generally parasites; which of the following class is exempted? [Orissa’06] (1) Trematoda (2) monopostnocotyla (3) turbellaria (4) cestoda

156 237. Commercial pearl is formed by [Orissa’06] (1) oyster (2) octopus (3) lamellidens (4) none of these 238. Bioluminescence is exhibited by [Orissa’06] (1) Chlorella (2) Hirudinaria (3) Chlamydomonas (4) Ceratium 239. Which is incorrect? [Orissa’06] (1) oligochaete- Pheretima (2) hirudina-Hirudo (3) nematoda-Ascaris (4) polychaete- Lumbricus 240. Which one is mismatched? [Orissa’06] (1) Hydra vulgaris- sea water (2) Hydra gangetica- fresh water (3) Obelia-sea water (4) Physalia- sea water 241. Which of the following is not related to porifers? [CPMT’06] (1) choanocytes (2) myocytes (3) cnidoblasts (4) thesocytes 242. Which of the following is a pseudocoelomate animal? [Kerala’06] (1) Aurelia (2) Planaria (3) Nereis (4) Wuchereria 243. The internal buds of fresh water sponges are other wise called [Kerala’06] (1) choanocyte (2) gemmule (3) osculum (4) blastula 244. Which one belongs to dipnoi [DPMT ‘02; Orissa ‘06] (1) Lung fish (2) Latimeria (3) Scoliodon (4) Petromyzon 245. A poisonous lizard is [MP ‘86; RPMT ‘96; AMU ‘06] (1) Heloderma (2) Ancistrodon (3) Chamaeleon (4) Varanus 246. An exclusive mammalian trait is [CPMT ‘87; BHU ‘94; RPMT ‘02; AIIMS ‘02; KCET ‘06] (1) Diaphragm (2) 4-chambered heart (3) Thecodont dentition (4) Vivipary 247. Retrogressive metamorphosis is seen in [Orissa’06] (1) Herdmania (2) Gambusia (3) frog (4) butterfly 248. Which of the following statement is true? [Kerala’06] (1) All living members of class cyclostomata are parasites on some fishes (2) there are about 2,000 species in the class Osteichthyes (3) Ciona belongs to the subphylum cephalochordata (4) Arthropods are diplobastic animals

BIOLOGY 249. Which of the following statements is/are not true? [Kerala’06] 1 in urochordata, notochord is present in larval tail. 2 in cephalochordata, notochord extends from head to tail region. 3 Branchiostoma belongs to hemichordata 4 only one class of living members, class Cyclostomata represents the super class agnatha (1) 1, 2, 4 only (2) 3, 4, 1 only (3) 3 only (4) 1, 4 only 250. Which of the following statements are true/false? [Kerala’06] 1 in Torpedo the electric organs are capable of generating strong electric shock to paralyze the prey 2 bony fishes use pectoral, pelvic, dorsal, anal and caudal fins in swimming 3 amphibian skin is moist and has thick scales 4 birds are poikilothermous animals 5 the most unique mammalian characteristic is the presence of milk producing mamary glands by which the yound ones are nourished (1) 1, 2 and 3 are true; 4, 5 are false (2) 1, 2 and 5 are true; 3 and 4 are false (3) 1, 4 and 5 are true; 2 and 3 are flase (4) 1, 2 and 4 are flase; 3 and 5 are true 251. Which one of the following is a matching pair of a body feature and the animal possessing it? [CBSE’07] (1) Ventral heart Scorpion (2) Post-anal tail Octopus (3) Ventral, Central Leech nervous system (4) Pharyngeal gill chamaeleon slits absent in embryo 252. What is true about Nereis scorpion, Cockroach and Silver fish? [CBSE’07] (1) They all belong to the same phylum (2) They all have jointed paired appendages (3) They all possess dorsal heart (4) None of them is aquatic 253. Which of the follwing pairs are correctly matched? [CBSE’07] Animals Morphological features (A) Crocodile 4 - Chambered heart (B) Sea Urchin Parapodia (C) Obelia Metagenesis (D) Lemur thecodont (1) Only A and B (2) A, C and D (3) B, C and D (4) Only A and D 254. What is common between parrot, platypus and kangaroo? [CBSE’07] (1) Ovoparity (2) Homoiothermy (3) Toothless jaws (4) Functional Post-anal tail 255. Which one of the following is NOT a characteristic of phylum Annelida ? [CBSE ‘08] (1) Ventral nerve cord (2) Closed circulatory system (3) Segmentation (4) Pseudocoelom

ANIMAL KINGDOM (PART-I & II) 256. Which one of the following groups of three animals each, is correctly matched with their one characteristic morphological feature ? [CBSE ‘08] Animals Morphological feature (1) Cockroach, Metameric Locust, Taenia segmentation (2) Liver fluke, Sea Bilateral anemone, Sea symmetry cucumber (3) Centipede, Prawn, Jointed Sea urchin appendages (4) Scorpion, Spider, Ventral solid Cockroach central nervous system 257. Which one of the following phyla is correctly matched with its two general characteristics ? [CBSE ‘08] (1) Mollusca Normally oviparous and development through a trochophore or veliger larva (2) Arthropoda Body divided into head, throax and abdomen and respiration by tracheae (3) Chordata Notochord at some stage and separate anal and urinary openings to the outside. (4) Echinodermata Pentamerous radial symmetry and mostly internal fertilization 258. Ascaris is characterized by : [CBSE ‘08] (1) presence of true coelom and metamerism (metamerisation) (2) absence of true coelom but presence of metamerism (3) presence of neither true coelom nor metamerism (4) presence of true coelom but absence of metamerism 259. Which one of the following groups of animals is bilaterally symmetrical and triploblastic ? [CBSE ‘09] (1) Sponges (2) Coelenterates (Cnidarians) (3) Aschelminthes (round worms) (4) Ctenophores 260. Which one of the following pairs of animals comprises ‘jawless fishes’ ? [CBSE ‘09] (1) Guppies and hag fishes (2) Lampreys and eels (3) Mackerals and Rohu (4) Lampreys and hag fishes 261. The intermediate host of Schistosoma is (1) snail (2) mosquito [BHU’09] (3) housefly (4) sheep 262. Which one of the following kinds of animals are triploblastic ? [CBSE ‘10] (1) Corals (2) Flat worms (3) Sponges (4) Ctenophores

157 263. Which one of the following statements about certain given animals is correct ? [CBSE ‘10] (1) Flat worms (Platyhelminthes) are coelomates (2) Round worms (Aschelminthes) are pseudocoelomates. (3) Molluses are acoelomates (4) Insects are pseudocoelomates 264. One example of animals having a single opening to the outside that serves both as mouth as well as anus is : [CBSE ‘10] (1) Fasciola (2) Octopus (3) Asterias (4) Ascidia 265. Which one of the following statements about all the four of Spongilla, Leech, Dolphin and Penguin is correct ? [CBSE ‘10] (1) All are bilaterally symmetrical (2) Penguin is homoiothermic while the remaining three are poikilothermic (3) Leech is a fresh water form while all others are marine (4) Spongilla has special collared cells called choanocytes, not found in the remaining three. 266. Phylum mollusca can be distinguished from other invertebrates by the presence of [DPMT’10] (1) Bilateral symmetry and exoskeleton (2) A mantle and gills (3) Shell and non-segmented body (4) A mantle and non-segmented body 267. Air bladder is present in [DPMT’10] (1) Chondricthyes (2) Star fishes (3) Actinopterygii (4) Flying fishes 268. Crocodile and penguin are similar to Whale and Dogfish in which one of the following features? [AIPMT Final ‘10] (1) Possess a solid single stranded central nervous system (2) Lay eggs and guard them till they hatch (3) Possess bony skeleton. (4) Have gill slits at some stage 269. The figure shows four animals (a), (b), (c) and (d). Select the correct answer with respect to a common characteristics of two of these animals. [CBSE’11 Final] (a)

(b)

(c)

(d)

(1) (a) and (d) have cnidoblasts for self-defence (2) (c) and (d) have a true coelom (3) (a) and (d) respire mainly through body wall (4) (b) and (c) show radial symmetry 270. Which one of the following animal phyla does not possess a coelom ? [WB-JEE’11] (1) Platyhelminthes (2) Annelida (3) Mollusca (4) Echinodermata

158 271. Which one of the following statements is totally wrong about the occurrence of notochord while the other three are correct [AIPMT Final ‘11] (1) It is absent throughout life in humans from the very beginning (2) It is present throughout life in Amphioxus (3) It is present only in larval tail in Ascidians (4) It is replaced by a vertebral column in adult frog 272. Which one of the following groups of animals is correctly matched with its one characteristic feature without even a single exception? [AIPMT’11] (1) Mammalia : give birth to young ones (2) Reptilia : possess 3-chambered heart with one incompletely divided ventricle (3) Chordata : possess a mouth provided with an upper and a lower jaw (4) Chondrichthyes : possess cartilaginous endoskeleton 273. Match the name of animal (column I) with one characteristic (column II) and the phylum/ class (column III) to which it belongs [AIPMT (NEET)’13] Column I Column II Column III (1) Petromyzon Ectoparasite Cyclostomata (2) Ichthyophis Terrestrial Reptilia (3) Limulus Chitinous exoskeleton Pisces (4) Adamsia Radially symmetrical Porifera 274. Which of the following are correctly matched with respect to their taxonomic classification? [AIPMT (NEET)’13] (1) Flying fish, cuttle fish, silver fish – Pisces (2) Centipede, millipede, spider, scorpion – Insecta (3) House fly, butterfly, TseTse fly, Silverfish- Insecta (4) Spiny ant eater, sea urchin, sea cucumber – Echinodermata 275. Which group of animals belongs to the same phylum? [AIPMT (NEET)’13] (1) Malarial parasite, Amoeba and Mosquito (2) Earthworm, Pinworm and Tapeworm (3) Prawn, Scorpion and Locusta (4) Sponge, sea anemone and star fish 276. One of the representatives of phylum Arthropoda is [AIPMT (NEET)’13] (1) Cuttle fish (2) Silver fish (3) Pufferfish (4) Flying fish 277. Which of the following animals lack alimentary canal (complete digestive system)? [AMU’13] (1) Earthworm (2) Jelly fish (3) Insects (4) Fishes 278. Name the character of phylum Aschelminthes which differentiates it from all other phyla of kingdom Animalia: [AMU’13] (1) Parasitic mode (2) Round in shape (3) Pseudocoelomate (4) Bilateral symmetry

BIOLOGY 279. Which of the following is an oviparous mammal? [AMU’13] (1) Balaenoptera (2) Delphinus (3) Pteropus (4) Ornithorhynchus 280. Torsion is the characteristic of: [AMU’13] (1) Gastropoda (2) Pelecypoda (3) Cephalopoda (4) Amphineura 281. The sound producing organ of the bird is called as: [AMU’14] (1) Syrinx (2) Larynx (3) Trachea (4) Glottis 282. A type of metamorphosis in insects with four developmental stages, i.e. eggs, larva, pupa and adult is [AMU’14] (1) Hemimetabolous (2) Paurometabolous (3) Holometabolous (4) Ametabolous 283. Select the taxon mentioned that represents both marine and fresh water species [AIPMT’14] (1) Echinoderms (2) Ctenophora (3) Cephalochordata (4) Cnidaria 284. Which one of the following living organisms completely lacks a cell wall? [AIPMT’14] (1) Cyanobacteria (2) Sea- fan (Gorgonia) (3) Saccharomyces (4) Blue- green algae 285. Planaria possess a high capacity of [AIPMT’14] (1) Metamorphosis (2) Regeneration (3) Alternation of generation (4) Bioluminescence 286. A marine cartilaginous fish that can produce electric current is: [AIPMT’14] (1) Pristis (2) Torpedo (3) Trygon (4) Scoliodon 287. The embryo sac of a typical dicotyledonous plant at the time of fertilization is [UP CPMT 2015] (1) 8 cells (2) 7 cells (3) 6 cells (4) 5 cells 288. Advantage of cleistogamy is (1) More rigorous offspring (2) No dependence on pollinators (3) Vivipary (4) Higher genetic variability

[UP CPMT 2015]

289. Wind pollination is common in [UP CPMT 2015] (1) Orchids (2) Legumes (3) Lilies (4) Grasses 290. The antigenic material(s) in the pollen wall that causes allergy is/are contributed by [UP CPMT 2015] (1) Exine (2) Pollen cytoplaym (3) Intine

(4) Exine and intine

ANIMAL KINGDOM (PART-I & II)

159

EXERCISE - 3 | Test Yourself 1.

2.

3. 4.

5.

6.

7. 8.

9. 10. 11.

12.

The members of the following group have exclusively open blood vascular system (1) Mollusca (2) Arthropoda (3) Both of these (4) Annelida Hemichordates have now been placed with the nonchordates, close to echinoderms, because true (1) Notochord is absent (2) Pharyngeal gill-slits are lacking (3) Dorsal nerve cord is absent (4) Heart is lacking Which of the following animal has compound eyes? (1) Octopus (2) Spider (3) Chameleon (4) Palaemon Peripatus has (1) Unjointed legs like parapodia (2) Jointed legs like arthopod-appendages (3) No legs (4) Well developed compound eyes Which one of the following mollusc is reared in fresh water for producing pearls? (1) Pinctada (2) Haliotis (3) Anodonta (4) Planorbis What is the correct about Cephalopods : (1) All have equal number of arms (2) All have internal shell (3) All are marine (4) Larval stages present Which of the following animal is deuterostome (1) Asterias (2) Sting ray (3) Lamprey (4) All of the above Which one is incorrect : (1) Silver fish is an insect (2) Wings to female Blatta orientalis are vestigial (3) Metamorphosis of insect is regulated by ecdysone (4) House-fly has siphoning type of mouth parts Which one is not aquatic (1) Wriggler (2) Maggot (3) Tadpole (4) Veliger What is absent in Arachnids : (1) Chelicerae (2) Pedipalp (3) Antenna (4) Eyes The body plan in the members of Aschelminthes is (1) Blind sac type, as in Platyhelminthes (2) Blind sac type, as in annelids (3) Tube— within –tube type, as in molluscs (4) Cell aggregate type, as in sponges. Which of the following feature is not applicable to all echinoderms? (1) Free moving (2) Marine (3) Eucoelomate (4) Mesodermal skeleton

13.

14.

15.

16.

17.

18.

19.

20. 21.

22.

On the basis of following feature the sponges can be differentiated from the coelenterates (1) Diploblastic body wall (2) Canal system (3) Asexual reproduction by budding (4) Acoelomate Shipworm is a (1) True worm (2) An annelid damaging wooden ships (3) A boring sponge (4) A bivalved mollusc In which set both the animals are true- worms? (1) Bladder worm and Ring worm (2) Tape worm and Hook worm (3) Pin worm and Flat worm (4) Round worm and Filaria worm Aristotle’s lantern which is a masticating organ of Echinoderms occurs in : (1) Echinoidea (2) Ophiuroidea (3) Holothuroidea (4) Asteroidea Which one of the statement is correct : (1) Arachnids have compound eyes (2) Arachnids (scorpion) has four pairs of legs (3) Arachnids have larva in their life cycle (4) None of the above The larvae of Echinoderms are (1) Asymmetrical (2) Radially symmetrical (3) Bilaterally symmetrical (4) Both (2) & (3) Which of the following has two hosts (1) Trypanosoma gambiense (2) Entamoeba histolytica (3) Ascaris lumbricoides (4) None of the above In which class of Echinodermata, Pluteus larva is formed (1) Crinoidea (2) Echinoidea (3) Asteroidea (4) Holothuroidea Which of the following character is related with the leech but not with the Earthworm? (1) Sanguivorous (2) Botryoidal tissue (3) 33 – segments in the body (4) All of these Aristotle Lantern is present in (1) Echinus and is a masticatory organ (2) Starfish and is a excretory structure (3) Octopus for jet propulsion (4) Sea Urchin and is a locomotory structure

160 23.

24.

25.

26.

27.

28. 29.

30.

31.

32. 33. 34.

35.

BIOLOGY Mark incorrect matching of excretory structures (1) Insects- Malpighian tubules (2) Prawn- Green glands (3) Starfish- Nephridia (4) Flukes-Flame cells The respiratory pigment in the following animal is haemocyanin (1) Earthworm (2) Cockroach (3) Pila (4) All of these Which one of the followings is never found in non-chordates (1) Dorsal Heart (2) Red blood corpuscles (3) Bilateral Symmetry (4) Solid nerve cord Neopilina is a connecting link between Annelida and Mollusca and belongs to the class: (1) Aplacophora (2) Polyplacophora (3) Monoplacophora (4) Gastropoda Which one of the following has closed circulatory system : (1) Cuttle fish (2) Silver fish (3) Cray fish (4) None of the above The excretory organ of Crustacean is called (1) Hepatopancreas (2) Green gland (3) Malpighian tube (4) None of the above Which group of protozoan shows nuclear dimorphism : (1) Vorticella, Didinium (2) Paramecium, Monocystis (3) Trichonympha, Trypanosoma (4) Opalina, Paramecium Scyphozoan medusae are more commonly known as (1) Sea anemones (2) Jelly fishes (3) Corals (4) Portuguese man of war Bombyx mori, a silk moth, is a (1) Holometabola insect like mosquito (2) Hemimetabola insect like bedbug (3) Holometabola insect like cockroach (4) Hemimetabola insect like butterfly Which of the following is a segmented mollusc?. (1) Chiton (2) Neopilina (3) Both of these (4) None of these Which of the following is a digenetic parasite? (1) Hook worm (2) Filarial worm (3) Pin worm (4) Round worm Platyhelminthes are (1) Triploblastic and acoelomate (2) Diploblastic and coelomate (3) Triploblastic and pseudocoelomate (4) Diploblastic and acoelomate Which one of these is not a typical character of class Nematoda (1) Non-living cuticle (2) Pseudocoel (3) Syncytial epidermis (4) Exclusively parasites

36. 37. 38.

39.

40. 41. 42.

43.

44. 45.

46.

47.

48.

49.

Dracunculus medinensis is commonly called (1) Hookwork (2) Seat worm (3) Pin worm (4) Guinea worm Transfer of Taenia to secondary host occurs in the form of (1) Cysticercus (2) Hexacanth (3) Onchosphere (4) Sporocyst Which pair of species belongs to the same genus (1) americana & orientalis (2) histolytica & proteus (3) coli & proteus (4) histolytica & coli Bilateral symmetry, segmentation, coelom and open circulatory system are the characters of (1) Arthropoda (2) Mollusca (3) Annelida (4) Platyhelmenthes Segmentation of body is not represented in : (1) Cray fish (2) Frog (3) Grasshopper (4) Starfish ‘Coral reefs’ are produced by the members of (1) Demospongia (2) Anthozoa (3) Scyphozoa (4) Hexactinellida Respiratory, Blood vascular and Skeletal systems are absent in the members of phylum. (1) Annelida (2) Porifera (3) Platyhelminthes (4) Echinodermata Which of the following animal is free swimming as a larva and sedentary as an adult (1) Jelly Fish (2) Sycon (3) Hydra (4) Ascaris Which of the following is a parasitic insect? (1) Housefly (2) Tick (3) Blatta (4) Flea Sub- kingdom Parazoa includes (1) Radially symmetrical animals like jelly fishes (2) All sessile, marine and colonial animals (3) Animals with cell aggregate body plan (4) Free swimming and acoelomate animals Triploblastic with organ system body plan, coelomate and unsegmented animals are seen in: (1) Echinodermata (2) Arthropoda (3) Ctenophora (4) Both (1) & (3) Planaria, Taenia and Blood Fluke (1) All are coelomate (2) All are found in gut (3) All are flat worms (4) Both (2) and (3) Which of the following is not the characteristic of Nematoda : (1) Cephalisation absent (2) Acoelomate (3) Eutely (4) Sexual dimorphism Prominent Gemmule in a sponge is : (1) An external bud (2) An internal bud (3) A Collection of choanocytes (4) A Sexual phase

ANIMAL KINGDOM (PART-I & II) 50.

51. 52.

53.

54.

55.

56. 57.

58.

59.

60. 61. 62.

63.

64.

Which one of the larva is found in the life history of fresh watered Molluscs : (1) Trochophore (2) Veliger (3) Glochidium (4) None of the above Parapodia are locomotory strucutres in (1) Arthropoda (2) Coelenterata (3) Echinodermata (4) None of these Mark the wrong combination (1) Taenia- Cercaria larva (2) Star Fish- Bipinnaria larva (3) Balanoglossus -Tornaria larva (4) Neries- Trochophore larva Which of the following animal is triploblastic but does not have coelom (1) Earthworm (2) Leucosolenia (3) Roundworm (4) Tapeworm Mark the right combination (1) Sycon - Water vascular system (2) Sea urchin - Canal System (3) Hook work - Pseudocoel (4) Cray Fish - Nematoblasts Which of the following animal has ‘Tube Tube within Tube’ body plan (1) Round worm (2) Liver fluke (3) Jelly fish (4) None of these Sedentary Echinoderms belong to (1) Crinoidea (2) Echinoidea (3) Ophiuroidea (4) Holothuroidea The animal in which the space between the body wall and the gut is filled with a parenchymatous tissue is called (1) Enterocoelomate (2) Schizocoelomate (3) Haemocoelomate (4) None of the above Identify a round worm which is digenetic and has Culex as secondary host : (1) Ancylostoma (2) Dracunculus (3) Trichuris (4) None of the above If earthworm, insect and snail are placed together, with which single word we can represent them : (1) Acoelomates (2) Deuterostomes (3) Protostomes (4) Enterocoelic The larvae produced by sporocyst of Fasciola are called (1) Redia (2) Miracidium (3) Cercaria (4) Matacercaria Which one of these animals is a ‘Deuterostome’ (1) Sea star (2) Sea Pen (3) Sea Fan (4) Sea mouse Which of the following animal cannot be differentiated into right and left halves? (1) Octopus (2) Ascaris (3) Hydra (4) All of these Which of the following animal is not metamerically segmented? (1) Millipede (2) Earthworm (3) Taenia (4) House fly Nauplius is the larva of (1) Cephalopods (2) Pelecypods (3) Crustaceans (4) Arachnids

161 65. 66.

67.

68.

69.

70. 71.

72.

73. 74.

75.

76.

In Ascaris the sperms are: (1) Immobile (2) Flagellated (3) Tailed (4) Ameoboid What is common to Hydra and Planaria : (1) Diploblastic condition (2) Tentacles (3) Blind sac body plan (4) None of these Which one of the set of animals have tracheae as respiratory organ : (1) King crab-scorpion-house fly (2) Crab-centipede-cockroach (3) Spider-cyclops-mosquito (4) Bedbug-sandfly-silk worm Whcih of the following animals has well developed nervous tissue but no brain : (1) Leucosolenia (2) Cockroach (3) Hydra (4) Both (1) & (3) The right sequence of larvae in the life history of liver fluke is : (1) Cercaria, Sporocyst, Redia, Miracidum and Metacercaria (2) Sporocyst, Redia, Miracidium, Cercaria and Metacercaria (3) Miracidium, Sporocyst, Redia, Cercaria and Metacercaria (4) Miracidum, Sporocyst, Cercaria, Redia and Metacercaria Cellulose degestion in termites is carried out by (1) Trichonympha (2) Trichomonas (3) Monocystis (4) Babesia Which set has both hermaphrodite animals? (1) Hydra and Star fish (2) Earthworm and Ascaris (3) Tape worm and Leech (4) Liver fluke and Prawn What is common amongst tape worm, planaria and liver fluke? (1) All segmented (2) All endoparasite (3) All coelomate (4) None of these. Which of the following is not a gut parasite? (1) Taenia (2) Oxyuris (3) Fasciola (4) All of these Notochord in Chordates is a flexible rod of tissue which lies: (1) In the dorsal region but ventral to nerve cord (2) In the ventral region but dorsal to nerve cord (3) In the dorsal region and dorsal to nerve cord (4) None of these In which of the following set both the animals belong to the same phylum? (1) Octopus and Leech (2) Scoliodon and Whale (3) Hag fish and Jelly fish (4) None of these The most characteristic feature of birds is: (1) Four-chambered heart (2) Present of wings (3) Bipedal locomotion (4) Presence of feathers

162 77.

In which group, the notochord is limited to a certain part only : (1) Urochordata (2) Cephalochordata (3) Hemichordata (4) All of the above 78. One of the following is a representative of Ratitae: (1) Hesperornis (2) Penguin (3) Kiwi (4) Archeopteryx 79. Which of the following shows close affinity with Dinosaurs (1) Heloderma (2) Crocodile (3) Turtle (4) Seymouria 80. Which of the following statement is correct? (1) All chordates are vertebrates (2) Few chordates are vertebrates (3) All vertebrates are chordates (4) All chordates are protochordates 81. The members of which chordate group can reproduce asexually by budding. (1) Tunicata (2) Cyclostomata (3) Cephalochordata (4) Ctenophora 82. Which of the following is not a lung fish? (1) Neoceratodus (2) Acipenser (3) Lepidosiren (4) Protopterus 83. Which of the following is the smallest toxonomic group of animals haveing cranium, vertebral column, ventral herat, pulmonary respiration and two pairs of limbs : (1) Gnathostomata (2) Tetrapoda (3) Vertebrata (4) Chordata 84. Identify one pinnipedia from the following (1) Bear (2) Sea lion (3) Whale (4) Sea cow 85. Hippopotamus is called “Horse of the river, it : (1) Belongs to perissodactyla (2) Has 4 ch ambered stomach (3) Is odd toed hoofed animal (4) All of the above correct 86. Petromyzon is commonly called as: (1) Hag fish (2) Blind worm (3) Lamprey (4) Acorn Worm 87 . The flying fish, Exocoetus, can glide in air with the help of modified (1) Air bladder (2) Pectoral fin (3) Tail Fin (4) Pelvic fin 88. Amphibians are not found in: (1) Ponds (2) Lakes (3) Rivers (4) Sea 89. The larva of petromyzon is known as (1) Axolotle (2) Tornaria (3) lamprey (4) None of the above 90. Which one of the following is a Metatherian (1) Tachyglossus (2) Ornithorhynchus (3) Macropus (4) All of the above 91. Birds differ from bats in the absence of (1) 4-chambered heart (2) Homeothermy (3) Diaphragm (4) Feathers

BIOLOGY 92. 93. 94.

95. 96.

97.

98.

99. 100. 101.

102.

103.

104. 105. 106.

Group Amniota does not include the members of (1) Amphibia (2) Pisces (3) Cyclostomata (4) All of these Heterocercal tail and placoid scales are found in (1) Labeo (2) Catla (3) Mystus (4) Scoliodon Ampullae of Lorenzini in dog fish are (1) Thermoreceptors (2) Rheoreceptors (3) Balancing structures (4) Auditory Structures Jacobson’s organ is concerned with (1) Smell (2) Burrowing (3) Touch (4) Vision Which of the following teeth are lophodont in elephant (1) Canine and premolar (2) Premolar and incisor (3) Incisor and canine (4) Premolar and molar Name the only protochordate with all basic chordate structures : (1) Amphioxus (2) Herdmania (3) Lamprey (4) Balanoglossus Following fish can move short distances on land because of the presence of gill chambers in mouth (1) Latimeria (2) Sting ray (3) Anabas (4) Exocoetus Axolotl is the larva of (1) Ambyostoma (2) Alytes (3) Varanus (4) Uromastix To which of the following order does Frog belong: (1) Urodela (2) Anura (3) Lagomorpha (4) Gymnophiona Which one of the following pair is correctly matched (1) Sphenodon - New Zealand (2) Ostrich - New Zealand (3) Kiwi - Australia (4) All of the above Birds possess : (1) Right ovary (2) Left aortic arch (3) One Urinary bladder (4) None of these Elasmobranchi is the group that includes : (1) Bony fishes (2) Lung fishes (3) Cartilaginous fishes (4) Lampreys and hag fishes Which of the following is a chordate but not a vertebrate? (1) Sea horse (2) Sea squirt (3) Sea hare (4) Sea cow Lung fishes belong to: (1) Elasmobranchi (2) Teleostomi (3) Dipnoi (4) Holocephali Both bats and whales are classified as mammals because both (1) Have 4 – chambered heart (2) Have Pinna (3) Give birth to young ones (4) Endothermic

ANIMAL KINGDOM (PART-I & II) 107. ‘Pigeon milk’ is secreted in the (1) Uropygeal gland of pigeon (2) Crop gland of female pigeon (3) Crop glands of male and female pigeon (4) Mammary glands of the pigeon 108. Foremen of Panizzae is associated with (1) Brain of Reptile (2) Kidney of Reptile (3) Heart of Reptile (4) Skeleton of Amphibia 109. Limbless Amphibians belong to the order : (1) Gymnophiona (2) Urodela (3) Anura (4) Caudata 110. The adult birds usually have single: (1) Kidney (2) Lung (3) Ovary (4) Urinary Bladder 111. The mammals which use echolocation device for hearing include Dolphins and the members of order: (1) Edentata (2) Chiroptera (3) Rodentia (4) Insectivora 112. Double headed ribs are present in: (1) Reptiles (2) Mammals (3) Birds (4) Both (2) and (3) 113. The study of birds migration is known as (1) Ornithology (2) Oology (3) Phenology (4) Nidology 114. Just as mammalia is to chordata, so is : (1) Cetacea to vertebrata (2) Ophidia to snakes (3) Periplaneta to insecta (4) Trematoda to platyhelminthes 115. Which of the following statement is not true for Agnatha : (1) They include hag fishes and lampreys (2) They have notochord through out their lives (3) They are known s cyclostomes (4) They have unpaired fins only 116. Which of the following animal is truly oviparous? (1) Bat (2) Sclay ant eater (3) Tachyglossus (4) Ornithorhyncus 117. Sea cows and sea lions belong to: (1) Same order Sirenia (2) Same order cetacea (3) Sirenia and Carnivora respectively (4) Cetacea and Sirenia respectively 118. Mark the snake whose venom is haemotoxic (1) Cobra (2) Krait (3) Hydrophis (4) Viper 119. The main difference between Gymnophiona and Urodela is that Urodels : (1) Have two atria & one ventricle (2) Have smooth moist skin (3) Respire by lungs in adult stage (4) Have a cloaca

163 120. Which one of the following characters does not relate to Amphibians : (1) Dicondylar skull (2) Amphicoelus centrum (3) 10 pairs of cranial nerves (4) None of the above 121. A pigeon in the absence of down feathers will not be able to (1) Keep the body warm (2) Fly for long distance (3) Protect against ectoparasite (4) Show sexual dimorphism 122. Which of the following bird is a brood parasite? (1) Crow (2) Dove (3) Humming bird (4) Eudynamis 123. The larvae of the following group show retrogressive metamorphosis (1) Urodela (2) Lacertilia (3) Anura (4) Ascidia 124. Which of the following is a poisonous mammal? (1) Ornithorhyncus (2) Sperm whale (3) Pteropus (4) Pangolin 125. Structure present in all adult vertebrates is : (1) Notochord (2) Dorsal tubular nerve cord (3) Pharyngeal gill slits (4) Renal portal system 126. Petromyzon is not a true fish because of (1) Absence of median fins (2) Presence of suctorial mouth (3) Absence of paired fins and true jaws (4) Absence of operculum 127. Post anal tail is present in : (1) Cobra (2) Earthworm (3) Scorpion (4) All of the above 128. Which of the following is a vertebrate but not a member of Tetrapoda? (1) Petromyzon (2) Bat (3) Pigeon (4) Amphioxus 129. Didelphis (Opossum) is (1) An egg laying mammal (2) A marsupial (3) A true placental mammal (4) Not a mammal 130. Following is the national animal of India: (1) Tiger (2) Lion (3) Cheetah (4) Leopard 131. All birds, without exception (1) Are Omnivorous (2) Have feathers and fly (3) Form nests and care them (4) Have calcareous shelled egg 132. Which one of the following statements is true as regard to a certain mammal and its feature : (1) Bats have feathers (2) Platypus is oviparous (3) Elephant is ovoviviparous (4) Camel has biconcave RBCs

164 133. Two chief feat features of mammals which distinguish them from other vertebrates are : (1) Hairy skin and oviparity (2) Hairy skin and mammary glands (3) Mammary glands and teeth (4) Pinna and teeth 134. The bat differs from bird in having: (1) Wings (2) Four-chambered heart (3) Feathers (4) Sweat glands 135. Which of the following is a non-poisonous snake? (1) Rattle snake (2) Glass snake (3) Rat snake (4) Sea snake 136. The first adult chordate that exhibits all major chordate characteristics belongs to (1) Tunicata (2) Hemichordata (3) Cephalochordata (4) Cyclostomata 137. Tunicin is the basic material of exoskeleton is : (1) Echinoderms (2) Cephalochordates (3) Hemichordates (4) None of the above

BIOLOGY 138. Birds have : (1) Amphiplatyon centrum and monocondylic skull (2) Hetroceoelus centrum and monocondylic skull (3) Hetrocoelus centrum and Dicondylic skull (4) Amphiplatyon centrum and Dicondylic skull 139. The mammals have hair but, they are absent in orders : (1) Proboscida & Cetacea (2) Ceatacea & Sirenia (3) Proboscida & Sirenia (4) All of the above 140. All the animals of the following set have Diapsid skull (1) Crocodile, Turtle and Seymouria (2) Natrix, Draco and Tortoise (3) Sphenodon, Crocodile and Viper (4) Calotes, Cobra and Pelycosaurus 141. Which of the following is a fossil placoderm : (1) Cephalaspis (2) Climatius (3) Latimaria (4) None of the above 142. In lancelet (1) Notochord is present in larva and absent in adult (2) Notochord is absent throughout (3) Notochord is present throughout the body (4) Notochord is partially replaced by vertebral column 143. Point out the toothless reptile from the following (1) Alligator (2) Monitorlizard (3) Tortoise (4) Sea snake

ANIMAL KINGDOM (PART-I & II)

165

ANSWER KEY EXERCISE 1 : NCERT BASED QUESTIONS 1. 6. 11. 16. 21. 26. 31. 36.

(2) (3) (3) (3) (4) (3) (1) (4)

2. 7. 12. 17. 22. 27. 32.

(3) (3) (3) (3) (2) (3) (4)

3. 8. 13. 18. 23. 28. 33.

(1) (3) (2) (3) (4) (2) (4)

4. 9. 14. 19. 24. 29. 34.

(4) (1) (3) (2) (4) (3) (3)

5. 10. 15. 20. 25. 30. 35.

(1) (2) (1) (1) (2) (3) (3)

EXERCISE 2 : WINDOW TO COMPETITIVE EXAMS 1. 6. 11. 16. 21. 26. 31. 36. 41. 46. 51. 56. 61. 66. 71. 76. 81. 86. 91. 96. 101. 106. 111. 116. 121. 126. 131. 136. 141. 146. 151. 156. 161. 166. 171. 176.

(3) (2) (4) (2) (4) (2) (1) (1) (1) (2) (3) (4) (1) (4) (1) (4) (1) (3) (1) (1) (1) (2) (1) (3) (1) (4) (2) (2) (1) (4) (3) (2) (4) (3) (3) (2)

2. 7. 12. 17. 22. 27. 32. 37. 42. 47. 52. 57. 62. 67. 72. 77. 82. 87. 92. 97. 102. 107. 112. 117. 122. 127. 132. 137. 142. 147. 152. 157. 162. 167. 172. 177.

(2) (2) (3) (1) (1) (3) (3) (2) (3) (1) (2) (2) (3) (3) (4) (4) (1) (3) (3) (3) (2) (4) (3) (1) (1) (1) (2) (2) (4) (2) (1) (1) (1) (1) (1) (3)

3. 8. 13. 18. 23. 28. 33. 38. 43. 48. 53. 58. 63. 68. 73. 78. 83. 88. 93. 98. 103. 108. 113. 118. 123. 128. 133. 138. 143. 148. 153. 158. 163. 168. 173. 178.

(2) (2) (4) (4) (4) (1) (3) (3) (4) (2) (3) (1) (1) (2) (1) (2) (3) (3) (1) (3) (1) (2) (4) (3) (1) (3) (2) (4) (1) (4) (1) (4) (3) (4) (1) (3)

4. 9. 14. 19. 24. 29. 34. 39. 44. 49. 54. 59. 64. 69. 74. 79. 84. 89. 94. 99. 104. 109. 114. 119. 124. 129. 134. 139. 144. 149. 154. 159. 164. 169. 174. 179.

(4) (4) (3) (2) (2) (4) (4) (4) (3) (1) (2) (3) (2) (3) (4) (3) (2) (1) (2) (3) (1) (4) (2) (1) (4) (4) (3) (2) (2) (4) (3) (1) (2) (4) (4) (1)

5. 10. 15. 20. 25. 30. 35. 40. 45. 50. 55. 60. 65. 70. 75. 80. 85. 90. 95. 100. 105. 110. 115. 120. 125. 130. 135. 140. 145. 150. 155. 160. 165. 170. 175. 180.

(1) (3) (3) (4) (2) (2) (4) (2) (2) (2) (2) (4) (2) (4) (2) (1) (3) (2) (2) (2) (2) (1) (2) (3) (4) (4) (3) (4) (2) (1) (3) (1) (1) (1) (3) (1)

181. 186. 191. 196. 201. 206. 211. 216. 221. 226. 231. 236. 241. 246. 251. 256. 261. 266. 271. 276. 281. 286.

(4) (2) (3) (4) (2) (2) (2) (2) (1) (2) (3) (3) (3) (1) (3) (4) (1) (4) (1) (2) (1) (2)

182. 187. 192. 197. 202. 207. 212. 217. 222. 227. 232. 237. 242. 247. 252. 257. 262. 267. 272. 277. 282. 287.

(3) (2) (4) (4) (3) (1) (2) (2) (3) (2) (1) (1) (4) (1) (3) (1) (2) (3) (4) (2) (3) (1)

183. 188. 193. 198. 203. 208. 213. 218. 223. 228. 233. 238. 243. 248. 253. 258. 263. 268. 273. 278. 283. 288.

(2) (4) (4) (4) (3) (1) (4) (3) (3) (4) (2) (4) (2) (1) (2) (3) (2) (4) (1) (3) (4) (2)

184. 189. 194. 199. 204. 209. 214. 219. 224. 229. 234. 239. 244. 249. 254. 259. 264. 269. 274. 279. 284. 289.

(4) (2) (3) (2) (4) (1) (1) (4) (3) (1) (3) (4) (1) (3) (2) (3) (1) (2) (3) (4) (2) (4)

185. 190. 195. 200. 205. 210. 215. 220. 225. 230. 235. 240. 245. 250. 255. 260. 265. 270. 275. 280. 285. 290.

(2) (1) (2) (3) (2) (1) (1) (4) (1) (1) (3) (1) (1) (2) (4) (4) (4) (1) (3) (1) (2) (4)

EXERCISE 3 : TEST YOURSELF 1.

(2)

2.

(1)

3.

(4)

4. 5. 6. 11.

(1) (3) (3) (3)

12.

(1)

13. 14. 15.

(2) (4) (4)

16. 21. 22 23 24

(1) (4) (1) (3) (3)

In open blood vascular system, the capillaries are absent and haemocoel is present. The structure which was earlier considered to be a notochord was found to be a buccal diverticulum. Compound eyes are present in only two groups of Arthropoda (Insecta and Crustacea). Peripatus has tracheal system for respiration. Pinctada also produces pearls, but is a marine form. 7. (4) 8. (4) 9. (2) 10. (3) In tube-within – tube body plan, the mouth as well as anal openings are present. The echinoderms of class Crinoidea are mainly sessile. The scientific name of ship worm is Teredo. The members of Aschelminthes (or Nematoda) are called true worms. 17. (2) 18. (3) 19. (1) 20. (2) Echinus is commonly called sea urchin. Star fish has nephrocytes for excretion. Besides Mollusca, the haemocyanin is also present in arthropods (except insects).

166

BIOLOGY

25. 30. 31.

(2) (2) (1)

32.

(2)

33.

(2)

34. 35. 40. 41.

(1) (4) (4) (2)

42. 43. 44. 45. 46. 51.

(3) (2) (4) (3) (1) (4)

52. 53. 54. 55.

(1) (4) (3) (1)

56. 61. 62.

(1) (1) (3)

63.

(3)

64. 69. 71.

(3) (3) (3)

72. 73.

(4) (3)

74.

(1)

75.

(2)

76. 77. 80. 81.

(4) (1) (3) (1)

82. 83. 86 87.

(2) (2) (3) (2)

26.

(3)

27.

(1)

28.

(2)

29.

(1)

Silk moth shows complete metamorphosis as it has larval and pupal stages. Neopilina is a connecting link between Annelida and Mollusca. The primary and secondary hosts of filarial worm are human and female Culex mosquito Platyhelminthes are first triploblastic animals. 36. (4) 37. (3) 38. (4) 39. (1) Coral reefs are formed by exoskeleton of calcium carbonate secreted by colonial coelenterate. The free swimming larva of Sycon is Amphiblastula. Tick is also an ectoparasite but not an insect. Parazoa includes porifers (sponges). 47. (3) 48. (2) 49. (2) 50. (3) Parapodia are the locomotory structures in the members of phylum Annelida. The larva of Taenia is Cysticercus or Bladder worm. Hook worm is a nematode (Aschelminthes). All groups higher than Platyhelminthes have tube-within tube body plan. 57. (4) 58. (4) 59. (3) 60. (1) Sea star (star fish) belongs to phylum Echinodermata. The animals with radial symmetry can not be differentiated into right and left sides. The segmentation in Taenia is false, and is called Strobilization 65. (4) 66. (3) 67. (4) 68. (3) 70. (1) Earthworm and liver fluke are also hermaphrodite or bisexual animals. All the three animals are acoelomate. Fasciola hepatica (liver fluke) is an endoparasite in the liver of sheep and goats. In case of vertebrates the notochord is replaced by vertebral column. Scoliodon (a fish) and whale (a mammal) both belong to phylum Chordata. Wings are present in insects and birds also. 78. (3) 79. (4) Some of the chordates are Invertebrates also. Tunicates (Ascidians) reproduce asexually by budding. Acipenser (sturgeon) is an anadromous bony fish. 84. (2) 85. (2) The scientific name of hag fish is Myxine.

88

(4)

89. 92.

(4) (4)

93. 94. 98. 99. 100. 101. 104.

(4) (1) (3) (1) (2) (1) (2)

105.

(3)

106.

(3)

107. 110. 111. 112.

(3) (3) (2) (4)

113. 116. 117. 118. 119. 122.

(3) (4) (3) (4) (2) (4)

123.

(4)

124.

(1)

125. 128.

(2) (1)

129. 130. 131. 134.

(2) (1) (4) (4)

135.

(3)

136.

(3)

137. 140.

(4) (3)

141.

(2)

Amphibians can be terrestrial, amphibious or fresh water forms. 90. (3) 91. (3) Amniota, having amnion, includes the members of classes Reptilia, Aves and Mammalia. These are the characteristics of cartilaginous fishes. 95. (1) 96. (4) 97. (1) Anabas is commonly called climbing perch. Axolotl larva shows Neoteny and Paedogenesis. Order Anura belongs to sub class Salientia. 102. (4) 103. (3) Sea squirt or Herdmania belongs to Tunicata (Protochordata). Dipnoi means having two types of breathing mechanisms. Presence of four-chambered heart and the endothermic condition are also shared by birds. Pinna are absent in whales. 108. (3) 109. (1) Urinary bladder is absent in birds. Chiroptera includes bats. Unlike the ribs of mammals, the birds have uncinate process in their ribs. 114. (4) 115. (2) The common name of Ornithorhyncus is Platypus. The rest three snakes have neurotoxic- venom. 120. (2) 121. (1) Eudynamis is commonly called as cuckoo. It lays eggs in the nest of crow. The tadpole larva of Herdmania has more advanced characters than the adult form. Ornithorhyncus or platypus has poison glands in the thigh region. 126. (3) 127. (1) Tetrapoda includes amphibians, reptiles, birds and mammals only. Opossum is found in South America. The scientific name of tiger is Panthera tigris. 132. (2) 133. (2) Sweat glands or sebaceous glands are present in mammals only. The common rat snake (Zamenis) is different from rattle snake, the later is poisonous. Amphioxus or Branchiostoma is the representative of Cephalochordata. 138. (2) 139. (4) Each member of Diapsida has two temporal fossa in the skull. Turtles and tortoises belong to Anapsida. 142. (3) 143. (3)

Chapter

5

Morphology of Flowering Plants While going through the chapter pay special attention to the following – Terms – 1. Calyptra 2. Napiform 3. Moniliform 4. Buttress root 5. Rhizome 6. Corm 7. Stolon 8. Sucker 9. Runner 10. Offset 11. Phylloclades 12. Cladodes Differences – (i) Phylloclades and cladodes. (ii) Hypogynous, perigynous and epigynous flower. (iii) Racemose and cymose inflorescence. (iv) Etaerios of berries, achenes, drupes and follicles.  

  

Angiosperms are flowering, fruit bearing, spermatophytic plants that are well adapted for land. These plants are the most advanced and evolved group that exists today. Angiosperms appeared in lower cretaceous period of mesozoic era but flourished in tertiary period of coenozoic era. They all have enclosed seeds and bear flowers. The flowering plants vary in size and ranging from small grasses to tall Eucalyptus or giant banyan trees. Angiosperms lack archegonium which is replaced by pistil. They have double fertilization and endosperm is triploid. The male gametes are nonmotile and carried by pollen tube to avoid dependence on water for fertilization. These plants have been broadly classified into monocots and dicots. Monocots are more advanced than dicots and have probably evolved from primitive dicots.



Plant morphology refers to the study of external form and structure of plants.



There are two major systems in flowering plants i.e., root system and shoot system.

THE ROOT

At a Glance 

Root Types of roots  Regions of roots  Modi�ication of roots Stem  Underground modi�ications of stems  Sub-aerial modi�ications of stems  Aerial modi�ication of stems Leaf  Types of leaves  Phyllotaxy  Modi�ications of leaves In�lorescence  Racemose and cymose in�lorescence Flower  Parts of �lower  Aestivation  Placentation Fruit  Classi�ication of fruit Seed  Monocot and dicot seeds Description of fabaceae, solanaceae, and liliaceae families 





 

  

Connecting Concepts

 In few hydrophytes root cap is absent and instead root pockets are The main characteristics of root are as following : present. A root pocket differs from a  It is the underground system, usually below the soil and originates from the radicle. cap in its mode of development. In  Generally it is positively geotropic, negatively phototropic and positively hydrotropic. Pandanus (screwpine), multiple root  The roots grow in downward direction for the purpose of anchorage and absorption of caps are present.

water and nutrients from the soil.



It lacks nodes, internodes, leaves and buds.



Unicellular hair and a terminal root cap or calyptra is present.

168

BIOLOGY The roots may be absent in some hydrophytes, but when present they are poorly developed and lack hair. Functions of root



  Connecting Concepts

The primary functions of root are fixation of plant firmly in soil, absorption of water and conduction of mineral nutrients. Roots also prevent soil erosion. The secondary or special functions of root include food storage, providing additional mechanical support, photosynthesis, respiration and vegetative multiplication, etc.

 In a hydrophyte Podostemon, root performs the function of assimilation Types of Roots and reproduction. It is a plant that is  Roots are divided into two types: all root.

(i)

 Roots are absent in some angiosperms, e.g., Utricularia, Wolffia, (ii) Balanophora, Cuscuta, etc. (i)

Tap roots Adventitious roots Tap root : Tap root or primary root develops from the radicle. It form lateral branches or secondary roots which are further branched to form tertiary roots. Thus tap root along with its branches, i.e., secondary and tertiary roots from tap root system. It is generally found

Tertiary roots Secondary roots

Lateral roots

in dicotyledons. (ii) Adventitious roots : These roots develop from any part of the plant instead of radicle. Adventitious root can be originate from base of stem, leaf, nodes and internodes.

}

Primary root A

B

Fig. 5.1 Root (A) Tap root (B) Fibrous or adventitious root

(a) Root arising from the base of the stem, e.g., maize, wheat, rice, onion, etc. (b) Roots arising from the leaf, e.g., Bryophyllum, Pogostemon etc. (c) Roots developing from the nodes and internodes of the stem, e.g., Ficus (banyan), Pothos (money plant), etc.

Regions of the Root 

A typical root can be differentiated into five distinct regions namely region of root cap, meristematic region, region of elongation, region of root hair and mature region. The first three regions take up little space whereas the last region forms the major part of the



root. Root cap (calyptra): Root cap is derived from calyptrogen. It covers root tip and protects it against friction from soil particles. Root cap being rich in starch grains responsible for geotropic response. Root cap is absent in epiphytes, parasites, hydrophytes and mycorrhizal roots.

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

Region of active cell division or meristematic region: This region is only 1 mm long. The growing point produces new cells for root cap and basal parts. It is, therefore, the zone of cell division. The cells of this region are thin and non-vacuolated.



Region of elongation: This region is 4-8 mm long behind the tip. The cells elongate rapidly due to vacuolization. This zone is responsible for growing of root in length.



Region of root hair: This region is 1-6 cm long. Outer cells just above the region of elongation give rise to lobular unbranched unicellular root hairs for increasing the absorptive area. Root hairs are absent in parasitic and mycorrhizal roots.



Region of cell maturation: The outermost layer of this region has thick walled or impermeable cells. So this region cannot help the root in water absorption. Its only function is to anchor the plant firmly in the soil. Lateral roots also arise from the interior of this region.

Modification of Roots 

Roots are modified to carry out some special functions, other than normal functions assigned to them like storage of food, additional mechanical support, photosynthesis, respiration and vegetative multiplication, etc.

Fig. 5.2 Zones or regions of a typical root

Modified tap root Tap roots are modified for the purpose of storage of food and are, therefore, fleshy and swollen. The modified tap roots are classified according to the shape they assume. 

Fusiform: It is a spindle-shaped root. It is swollen in the middle and tapering at both the ends e.g., radish ((Raphanus sativus).



Napiform: It is much swollen at the upper end and abruptly tapering towards the lower end e.g., turnip ((Brassica rapa) and beet.



Conical: The conical root is broadest at the top (base) and gradually tapering towards the lower end. The hypocotyl does not contribute to the swollen root e.g., carrot ((Daucus carota).



Tuberous: T Tap root is irregularly swollen except at the base, e.g., 4 o’clock plant (Mirabilis jalapa).



Nodulated (tuberculated roots): In legumes, the roots are symbiotically associated with the nitrogen-fixing bacterium, Rhizobium leguminosarum. This results in the formation of several nodules in the branches of the roots. Nodules are pinkish due to pigment leghaemoglobin which carry oxygen and provide anaerobic environment in nodules for nitrogenase enzyme to fix nitrogen.

(A)

(B)

(C)

Fig. 5.4 (A) Napiform root of Turnip (B) Tuberous root of Mirabilis. (C) Nodulated root of a legume.

Fig. 5.3 (A) conical root of Carrot. (B) fusiform root of Radish.

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BIOLOGY

Modified adventitious roots 

Tuberous : These roots arise from nodes of stem and one root out of bunch become tuberous and fleshy for storage of food, e.g., Sweet potato ((Ipomoea batatas).



Fasciculated : Fasciculated roots arise in bunches (fascicles) from lower nodes of stem and become thick and fleshy for storage of food, e.g., Asparagus, Dahlia.

Fig. 5.5 Tuberous roots of Ipomoea batatas ((sweet potato)

Fig. 5.6 Fasciculated roots of Dahlia



Beaded or Moniliform roots : Due to food storage these roots swells at different places forming a beaded structure e.g., Vitis, Momordica and some grasses.



Nodulose : In these roots terminal portions swell up, e.g., Curcuma amada.

 

Fig. 5.7 Moniliform

Fig. 5.8 Nodulose roots

roots of Grass

of Curcuma amada

Annular: In these roots swelling at different places takes place in such a way that it looks like stack of rings, e.g., Psychortia. Prop roots: Some plants are profusely branched and branches are thick and heavy. From these branches roots arise and hang downwards in the air and later penetrate the soil and function as prop (for support) to the branch, e.g., Ficus bengalensis (Banyan).

Fig. 5.9 Annular roots

Fig. 5.10 Prop roots of Banyan

of Psychortia



Stilt roots: In some plants roots arise from lower nodes of stem and enter the soil and become stronger. They protect the plant against winds, e.g., sugarcane, maize, screwpine.

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171

Climbing roots : In Pothos, Piper beetle, adventitious roots arise from nodes and help the plant in climbing. These roots produce a viscous substance which dries in the air and so the roots get attached to substratum. Buttress roots : These are horizontal roots arise from basal part of main stem and spread in different directions in the soil. They are irregular, thick, broad, like planks of wood, e.g., Bombax, Ficus.

Internode

Node Stilt root

Climbing roots

Fig. 5. 11 Stilt roots of sugarcane Fig. 5.12 Climbing roots of Piper beetle

 

Fig. 5.13 Root buttress of Bombax

Contractile roots : Underground stem of plants, like Chrocus and Onion roots are meant for keeping storage stems at a proper depth in the soil. Their apical part contracts and fixes the plant in the soil. Sucking roots: Parasitic plants like , Cuscuta roots arise from the stem and enter the host plant developing contact with xylem and phloem of the host stem. Such roots are called haustoria (= sucking roots) Host plant

Flower bud Parasite plant

Original position

Contractile roots

Haustoria (A)

Fig. 5.14 Contractile roots of Chrocus





Stem of host (B)

Fig. 5.15 Sucking root of Cuscuta

Epiphytic or Hygroscopic roots :These aerial hanging roots present in epiphytes (plants growing on other plants for space only). These roots have a spongy tissue called velamen (outside the cortex). Cell of velamen are dead and have pores for the absorption of atmospheric moisture. Root cap and root hairs are absent, e.g., Orchids. Floating root : These are adventitious roots present in some floating plants like Jussiaea. Spongy aerial roots filled with air help the plant in floating. Epiphyte plant

Clinging roots Floating roots

Support Aerial roots

Fig. 5.16 An orchid showing: epiphytic and clinging roots

Fig. 5.17 Floating roots of Jussiaea

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BIOLOGY  

Assimilatory or Photosyntheitc roots : Roots of some plants develop chlorophyll and perform photosynthesis, e.g., Trapa, Tinospora Reproductive roots : In sweet plants, Asparagus, Dahlia vegetative buds arise on adventitious roots which after separation from parent plant form new plants.



Mycorrhizal roots : Roots of some plants which grow in humus soil have fungal hyphae. Root of such plants do not have root hair and fungal hypae function as root hair, e.g., Pinus.



Roots thorns : Plants like Pothos, roots near the soil become hard like thorns. These thorns serve as protective organ.



Clinging roots : These roots arise from node of a stem and pierce the stem of host plant and thus help in fixing the plant to the host Orchid and Ivy.

Fig. 5.18 Assimilatory roots of Trapa

Root thorns

Adventitious root buds

Clinging roots

Fig. 5.19 Reproductive roots of Trichosanthes

Fig. 5.20 Mycorrhizal roots of Pinus

 

Fig. 5.21 Root thorns of Pothos

Fig. 5.22 Clinging roots of Ivy

Leaf roots : In some plants adventitious roots are produced on the margin of leaves, e.g., Bryophyllum and Bignonia. Pneumatophores: Pneumatophores or respiratory roots are short, vertical and negatively geotropic (grow in an upward direction). It occur in certain halophytes, which grow in saline marshes (mangroves). They bear numerous minute pores or special lenticels (pneumatothodes) in their terminal parts that help in taking atmospheric oxygen which is completely absent in the saline water e.g., Rhizophora, Heritiera (‘sundari’), Avicennia (‘bina’). Stem

Pneumatophores

Adventitious leaf buds

Fig. 5.23 Leaf root of Bryophyllum

Fig. 5.24 Leaf root of Rhizophora

SHOOT SYSTEM It is an aerial system, usually above the soil and originates from the plumule. It consists of stem, branches, leaves, flowers, fruits and seeds. Characteristic features of the stem • It is a direct prolongation of the plumule. 

•

It is negatively geotropic and positively phototropic.

•

It bears branches, leaves and flowers.

•

It is distinguishable into nodes and internodes. It lacks a terminal cap.

MORPHOLOGY OF FLOWERING PLANTS •

A node is formed at the place from where a leaf arises i.e., the place of origin of a leaf on the stem apex is differentiated as the node.

•

The space between two successive nodes is called internode.

•

The branches and leaves arise from the nodes. It often bears multicellular hairs.

•

The growth of shoot system is accomplished by buds. The buds may be vegetative or flowering.

173

Functions of stem Stem facilitates conduction of water, mineral and food material. It also produces and supports leaves and reproductive structure.

Modifications of Stem 

The stem and branches of certain plants undergo various types of modifications to perform special type of functions such as: (a) perennation by underground modifications; (b) vegetative propagation by sub-aerial modifications and (c) specialised functions by aerial modifications.

Underground modifications of stems    







Some perennial herbs develop their stems underground for the purpose of perennation during unfavourable conditions. The stem produces aerial branches every year when conditions become favourable. The underground stems are usually very thick as a result of heavy deposit of food within them and hence they also act as storage organs. Besides they also help in vegetative propagation by means of their buds. These stems are non-green and leafless like roots but differ from them in the following way : • Presence of nodes and internodes, scale-leaves, axillary and terminal buds. • Absence of root hair and root cap. The various types of underground modifications of stem are as follows : Rhizome : Rhizomes are colourless and apparently leafless and, therefore can be mistaken as roots. • It is a thick and prostrate stem. It grows horizontally forward under soil surface. Fig. 5.25 Rhizome of Ginger • Nodes and internodes are very distinct. • Generally branched. • Bears several axillary and terminal buds. Bud • It bears adventitious roots all over. • E.g., Musa (plaintain), Canna, Zingiber (ginger), Curcuma (turmeric), ferns etc. Lateral bud Corm : Node Internode • It is highly swollen vertical stem. Adventitious • Nodes and internodes are not very distinct. roots • Generally unbranched. Fig. 5.26 Corm of Crocus • Bears few axillary and terminal buds. • Adventitious roots are borne by basal nodes only. • E.g., Saffron (Crocus), Colocasia, Dioscorea, Colchicum, Gladiolus and ‘Zamikand’ ( (Amorphophallus ), and Fressia. Tuber : Shoot • Irregularly shaped swollen stem. New shoot • Stores plenty of food. • It is differentiated into nodes and internodes. The ‘eyes’ on potato tuber indicate Axillary bud – Eye axillary buds at the nodes. Roots • It bears scaly leaves. The leaves do not store food. Tuber • Axillary buds arise at the nodes. Fig. 5.27 Tuber of potato • Does not bear roots. • Eg., Solanum tuberosum (potato).

174

BIOLOGY 

Bulb : • It is characterised by having a discoid stem. • Does not store food. • Since it is highly reduced, nodes and internodes are not distinct. • It bears large and fleshy scaly leaves which store food. • Axillary buds arise in the axil of fleshy leaves. • Bears several fibrous root. •

The bulbs are of two types, scaly or imbricate (garlic) and tunicate (onion). Outer scaly Outer scaly leaves leaves Scale leaves Scale leaves Fleshy Fleshy leaves leaves Apical Apical bud bud Axillary Axillary bud bud Stem Stem

Connecting Concepts  The odour in onion and garlic is due to allyl sulphonate, called allocinin and eye tearing is due to volatile thiosulphonates. The anticancerous substance in garlic is gernium.  When the runners are with thick internodes, they are called sobole.

Fig. 5.28 Bulb of onion

Bulbets Bulbets (Foodininfleshy) Fleshy) (Store food Leaves leaves

Fig. 5.29 Bulb of Garlic

Sub-aerial modifications

These are horizontally growing branches which grow either just above the surface (sub-aerial) or just below the surface of the soil. They are produced for the purpose of vegetative propagation. The various types of sub-aerial modifications are runner, sucker, stolon and offset.  Runner : Such plants have long and thin internodes and branches creep over the surface of soil. Such branches develop adventitious roots at nodes on lower side. When long branches break up by any method they form new plants. In this way large Runner  number of new plants are formed. e.g., Doob grass, Oxalis, Hydrocotyle. Soil  Sucker : This stem also arises from the axillary branch arising from the node of underground New plant Adventitious stem. Such a branch moves obliquely or sometimes grows horizontally under the surface from axillary roots bud of soil and then comes out of the soil growing obliquely upwards. Fig. 5.30 Strawberry  Adventitious roots arise from the nodes of underground portion of stem. Branches break up from the parent plant, thus forming a new independent plant, e.g., Chrysanthemum, Rose, Mint.  Stolon : Branches of some plants arise from nodes of underground portions of stem and grow in the horizontal direction. After growing for sometime the apical region of the branches comes out of the soil, grows into air and roots arise from lower side of nodes.  It is like a runner with the difference that the stolon grows horizontally below the soil Soil surface while the runner grows above the surface of soil, e.g., Colocasia, Strawberry. New suckers  Offset : This stem is like a runner but the internodes are thicker and shorter.  Branches arise all around the main stem. Apex of each branch gets curved upwards bearing Old sucker of a group of leaves at the apex and a bundle of adventitious roots below. the parent plant Fig. 5.31 Chrysanthemum  The branches break off from the parent and become an independent plant, e.g., Pistia, Eichhornia (Water hyacinth). Stolon Parent plant Scale leaves Daughter rosette

Soil

Adventitious roots

Roots Fig. 5.32 Blackberry

Fig. 5.32 Houseleek (water plant)

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175

Aerial modifications

Connecting Concepts

The aerial modifications help the plants to survive during unfavourable conditions by storing food, propagation and providing support and protection. Some aerial modifications are stem thorn, stem tendrils, phylloclade or cladophyll, cladode, bulbil and prickles.  Stem tendrils : Tendrils are thread-like sensitive structures which can coil around a support and help the plant in climbing. They may be branched or unbranched.

 Thorn, spikes and prickles are sharp, pointed, straight or curved, hard structures performing similar function. Thorns are modified stem while spikes are modified leaf or leaf part. Both of them have cortex and vascular supply. Prickles are epidermal outgrowth of stem that do not have vascular supply.

Fig. 5.34 Types of stem tendrils

 

Stem thorn : They are stiff, sharp structures which have lost their growing point and become hard e.g., Citrus, Bougainvillea, Duranta, Pomegranate, Alhagi, etc. Phylloclades : They are flattened e.g., Opuntia, or cylindrical (e.g., Casuarina, Euphorbia) green stems of unlimited growth which have taken over the function of photosynthesis. Formation of phylloclades helps the plant to grow in dry habitats because transpiration is less by the stem. In some cases phylloclades store water, mucilage and latex.

Thorn Leaves modified as spines Phylloclade

Cladodes Roots

Fig. 5.35 Stem thorn

  

Cladodes : They are green stems of limited growth (usually one internode long) which have taken over the function of photosynthesis from the leaves. The true leaves are reduced to scales or spines. In Ruscus aculeatus cladodes are leaf like in appearance with spiny tip, ovate outline and roughly parallel veins. In Asparagus the cladodes are slightly flattened, fleshy, straight or curved pointed structure which develop in clusters in the axils of scale leaves.

LEAF 



Fig. 5.36 Phylloclade of Opuntia

A leaf is green, dorsoventrally flattened, exogenous lateral outgrowth that arises from a node of the stem or a branch. The leaf is a specialised organ of photosynthesis, transpiration and gaseous exchange. Leaf generally bears a bud in its axil called axillary bud which later develops into a branch.

Scaly leaf (A)

Fig. 5.37 (A) Cladodes of Asparagus

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BIOLOGY Connecting Concepts

Parts of leaf or phyllopodium

 Dicot leaf is dorsiventral and The leaf is distinguishable into three parts namely leaf base, petiole and lamina. horizontal in position. Monocot leaf is  Leaf Base: It is the point of attachment of the leaf petiole to the stem. In some leguminous isobilateral and vertical in position.

 Lamina Stipule

 e Axillary Leaf bud base Fig. 5.38 Parts of a leaf ol Peti



plants, leaf base is swollen which is called pulvinus. Stipules : Stipules are a pair of lateral outgrowths arising from the leaf base in most of the dicots. Sometimes a stipule is an appendage of the leaf base itself. Their main role is to protect the young axillary buds. A leaf may have stipules (stipulate) or may not have any stipule (exstipulate). Petiole : It is the stalk of the leaf. When a distinct petiole is present, the leaf is said to be petiolate, and sessile when it is absent. An intermediate condition called sub-sessile is seen when a poorly defined petiole is present. The petiole may be tendrillar in Clematis, Nepenthes, swollen in Eichhornia and winged in Citrus. Lamina : Lamina is usually flattened green photosynthetic part of leaf. Its upper surface is called adaxial while lower surface is called abaxial.

VENATION Venation is the arrangement of the veins and the veinlets in a leaf. It is of two types : VENATION

Reticulate Venation

Parallel Venation

The veins are arranged in a net like

The veins are arranged parallel

manner, e.g., Dicots.

to each other, e.g., Monocots.

Reticulate Network

Pinnate (Peepal leaf) (A)

Palmate (Canna leaf) (B)

Fig. 5.39 (A) Reticulate venation (B) Parallel venation

Types of the leaves A leaf may be simple or compound depending upon the incision of lamina.  Simple leaf : In simple leaf lamina is not divided completely into distinct leaflets.  Compound leaf : In compound leaf, incision of leaf blade goes down to the rachis so the leaf is broken up into number of segments called leaflets. The compound leaves are of two typespinnate and palmate. • Pinnate. These are feather like leaves. The segmentation of the leaf-blade is towards the mid-rib, so that the leaflets are borne laterally by midrib or rachis. • Palmate. They are fan-like having leaflets which are borne at the tip of the petiole. In palmate compound leaves the segmentation (A) (B) of the leaf extends from the apical margin to the petiole so that the leaflets are articulated Fig. 5.40 Compound leaves to the tip of the petiole like fingers on a (A) Pinnately compound leaf palm. (B) Palmately compound leaf

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Phyllotaxy

Connecting Concepts

 Ptyxis is the manner of folding of an individual leaf in bud condition, e.g., circinate ptyxis (folding or rolling of leaf from apex to base as in ferns).  Leaf duration  Caducous: The leaves falling off soon Opposite: In opposite Whorled or Alternate acyclic or after their formation, e.g., Opuntia. phyllotaxy, two leaves occur at  Deciduous (Annual): Falling off Verticillate: spiral : Only one leaf each node. It is of two types : under unfavourable conditions or at the is borne at each node – Decussate : When the When more than two end of growing season e.g., Mulberry, successive pairs of leaves in alternate manner leaves occur at a Poplar. arise at right angles to the e.g., mustard, node, the phyllotaxy  Persistent (Evergreen): Leaves preceeding pair, the sunflower plants. remain on the plant for more than one is said to be whorled, phyllotaxy is said to be year, fall off individually at different opposite decussate, e.g., e.g. Nerium, times so that the plant gives an Calotropis, Ocimum etc. Alstonia etc. evergreen look, e.g., Eucalyptus. – Superposed: When the  In Lathyrus aphaca (wild pea) whole successive pairs of leaves leaf while in Pisum sativum (sweet pea) on a branch arise in one the apical leaflets are modified into vertical plane, the phyllotaxy is said to be tendrils. In Goloriosa leaf tip modifies opposite superposed e.g., while petiole in Clematis, terminal Quisqualis psidium. leaflets in Narvelia, stipules in Smilax, etc.  Sometimes other parts of leaf also Modifications of Leaves modify into spines, e.g., apex of leaf  Leaf tendrils : The leaves or their portions may become modified into tendrils in various in Phoenix and Yucca, leaf margin in Argemone, both apex and margin in plants. Tendrils help in climbing, e.g., Smilax, Clematis, Nepenthes. Aloe barbedense, stipules in Acacia, Leaflet Zizyphus jujube, etc.

The arrangement of mature leaves on the stem or its branches is called phyllotaxy. Different arrangements of leaves are meant so that every leaf get maximum amount of sunlight. It is of three types: 

tendril

Pinnately compound leaf

Whole leaf tendril Leafy stipules Weak stem

Leaf stipules

Phyllode Fig. 5.41 Types of leaf tendrils (A) Whole leaf tendril of Lathyrus aphaca (B) Leaflet tendril of Lathyrus odoratus





 

Leaf spines: In a number of plants, leaves or their parts are modified into spines either to escape transpiration (Opuntia, Asparagus,etc.) or for protection (Barberry).

Spiny apex Marginal spines

Phyllode: In Acacia auriculiformis (Australian acacia), Parkinsonia, etc., the leaf or lamina sheds and the petiole modifies into leaf like structure. It also performs the function of synthesis of food. Scale-leaves: In onion, scale-leaves store food and water and are, therefore, thick and fleshy.

Fig. 5.43 Phyllode of Acacia

Base Lid Collar (A)

Tendril

(B)

Fig. 5.42 Leaf spines

Pitcher: The leaf-blade is modified into a pitcher-like (A) Aloe (B) Argemone structure. The pitcher is provided with a lid which itself is an outgrowth of the leaf-apex. The petiole is modified into a tendrilar structure to hold the pitcher in a vertical manner.

Pitcher

Fig. 5.44 Leaf pitcher of Nephenthes

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BIOLOGY



Connecting Concepts

•

Non-insectivorous pitchers : Leaves are modified into non-insectivorous pitchers in which adventitious root enters and absorbs the accumulated humus, e.g., Dischidia rafflesianz.

•

Insectivorous pitchers : Leaf is modified for the purpose of capturing insects. e.g., Nepenthes, Sarracenia, Cephalotus, Heliamphora.

Leaf Bladder : In bladderwort (Utricularia), which is a submerged floating hydrophyte, some of the leaf segments get modified into tiny bladders. The bladder like structure is meant for catching the aquatic insects, etc. for their nitrogen content.

THE INFLORESCENCE

 Families named after inflorescences: Umbelliferae (umbel inflorescence) An inflorescence is the mode of arrangement of flowers on peduncle or mother axis. Inflorescence and Amentiferae (Amentum or Catkin makes flower more conspicuous to pollinating agents to facilitate cross pollination. Air inflorescence).

pollination also becomes easier as large number of pollens are shed from a group of flowers in

 Inflorescence called flower: inflorescence. Cauliflower (compound corymb), Sunflower (capitulum), Euphorbia There are two types of inflorescence i.e., racemose and cymose. (cyathium).

Racemose (Indeterminate or Indefinite) Inflorescences The main axis of racemose inflorescence has indefinite growth because there is no terminal flower. The flowers are borne laterally in acropetal succession, i.e., oldest flowers are borne at the base and younger ones are borne near the tip. The prominent racemose inflorescence are as follows : (A) Main Axis Elongated (Racemose with long peduncle) (i) Raceme : Main axis is elongated and flowers are pedicellate, e.g., Larkspur, Mustard, Radish. Flowers (stalked) Fruit

Flowers (sessile)

Leaf

Stem (A)

(B)

(C)

Fig. 5.45 (A) Raceme of Mustard (B) Spike of Achyranthes aspara, (C) Catkin of Mulberry

(ii) Spike : Main axis is elongated but flowers are sessile, e.g., Achyranthes. (iii) Catkin : Pendulous spike which bears naked pistillate or staminate flowers (but not both e.g., Mulberry). (iv) Spadix : Spike with fleshy axis and having both male and female flowers. It is surrounded by a large bract (usually brightly coloured) called spathe, e.g., Palm, Colocasia. Musa (banana) produces compound or mixed spadix.

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179

(v) Spikelet : A very small spike with one or a few flowers (florets). Each spikelet bears at its base two minute bracts called empty glumes, slightly higher up, it bears a third bract called flowering glume or fertile glume or lemma or lower palea. Opposite to the lemma it bears a small glume called upper or superior palea. Each flower of the spikelet remains enclosed by a lemma and palea, e.g., Family-Gramineae (wheat, rice, bamboo). Feathery Stigma Gynoecium Spathe Sterile portion of spadix

Androecium Lodicule Inferior palea or lemma (Fertile glume)

Male flowers

Second empty glume Superior Palea

Neuter flowers Rachilla (axis)

Female flowers

(A)

First empty glume

(B)

(C)

Fig. 5.46 (A) and (B) Spadix of Colocasia antiquorum (C) Spikelets of wheat

(B) Main Axis Shortened (Racemose with short peduncle) (i) Corymb : The main axis is comparatively short, and the lower flowers have much longer pedicels than the upper ones so that all the flowers are brought more or less to the same level, e.g., Candytuft ((Iberis). (ii) Umbel : The main axis is very much reduced and all flowers appear to be originating from the same point. The younger flowers are in the center and older ones towards the periphery. The flowers are usually bracteate e.g., Hydrocotyle (or Centella) (Indians pennywort), Prunus.

(A) Fig. 5.47 Corymb of Prunus cerasus (old)

(B)

Fig. 5.48 (A) Umbel of Prunus cerasus (young) (B) Outline plan

180

BIOLOGY (C) Main Axis Flattened (Racemose with flattened) Capitulum (= Head) : The receptacle is flattened and bears numerous sessile and small florets in a centripetal manner, i.e., youngest Stigma in the center and older towards the periphery. Style Individual florets are bracteate. Also the whole Anther cluster of florets is surrounded by a whorl of Corolla bracts collectively called involucre. Two kinds of florets can be recognized on the receptacle. Calyx (i) Ray florets : Arranged on the periphery Ovary of receptacle having distinct yellow Disc floret Ray floret colour and strap shaped petals. These Fig. 5.49 Capitulum of sunflower florets are female or sterile and are always with disc and ray florets zygomorphic. They may be arranged in one or more whorls. (ii) Disc florets : Placed in the center and are bisexual and actinomorphic.

Cymose Inflorescence The growth of the main axis is definite because the growing point of peduncle is used up in the formation of a flower. Further growth of flowering axis is continued by one or more lateral branches which also end in flower. The flowers are borne in a basipetal (centrifugal) succession i.e. the oldest flower is borne at the top and the younger ones are lateral. The cymose inflorescence are of the following types : A.

Uniparous (= Monochasial cyme) : A single lateral branch arises from the peduncle of old flower which terminates in a flower. Another lateral branch arise on the first lateral branch also terminates in a flower. Monochasial cyme can be of two types : (a) Helicoid cyme (or one-sided) Cyme : The main axis ends in a flower. Its lateral branches arise from the main axis on one side again ends in a flower. This branch gives rise to another lateral branch on the same side, i.e. all the lateral branches arise either on left side or right side forming a sort of helix, e.g. Myosotis palnstris, Drosera. It has two types : (i) Drepanium : All flowers in one plane. (ii) Bostryx : Flowers are borne in different planes. (b) Scorpoid cyme : In this case the lateral branches arise alternately on left and right sides e.g., Heliotropium, Ranunculus. It has two types : (i) Rhipidium : It is scorpioid cyme in which flowers occur in one plane. (ii) Cincinnus : Flowers are borne in different planes. 1

5 4

5

3 2 1

3

2

4 3 2 1

A

A

B B Fig. 5.50 A. Helicoid cyme outline plan, Fig. 5.51 A. Scorpoid cyme outline plane B. Myosotis palustris B. Ranunculus bulbosus

B.

Biparous cyme (= Dichasial cyme) : In biparous cyme the main axis bears a terminal flower and stops growing. This main axis bears two bracts at a node from which arise two branches, one on each side which also terminate in flowers. (Thus there are 3 flowers – oldest in the center). From the pedicel of each lateral flowers further branching may arise repeatedly, e.g., Stellaria media, Spergula arvensis, Dianthus chinensis.

MORPHOLOGY OF FLOWERING PLANTS C.

181

Multiparous cyme (= Polychasial cyme) : The main axis bears a single terminal flower and below it more than two lateral branches arise at a node. They also bear terminal flowers. The oldest flowers are in the center and terminates the main axis. In Hamelia this simple polychasial cyme become biparous and ultimately uniparous during further branching. In Calotropis there is umbellate cyme, i.e., groups of multiparous cymes in which main axis becomes very much short (Fig B) Flowers 2

Buds

2

3

3

3

3

1

Leaf A

C

B

Fig. 5.52 A. Dichasial cyme Dianthus chinensis, B. Polchasial cyme Hamelia, C. Cymose hand of Acacia

D.

E.

Cymose Head : In Acacia nilotica (Keekar) and Albizzia lebbek, the main axis is condensed to a circular disc. It bears sessile flowers (or sub sessile). The oldest flower is in the center and youngest towards the periphery of the disc (centrifugal). The flowers form a compact globose head. Scapigerous head : In Allium cepa (Onion) the leafless flowering axis is known as scape. It bears cluster of flowers that form a head which is covered by one or more bracts called spaths. This head of flowers has many umbellate cymes.

THE FLOWER  





Connecting Concepts

The flower is the most characteristic structure of the angiosperms. It is a complex unit consisting typically of those parts which directly or indirectly contribute to the process of reproduction. Flower is highly modified and condensed shoot meant essentially for the sexual reproduction of the plant. It develops on the axis called mother axis or peduncle. A flattened peduncle is called receptacle. The stalk of flower is called pedicel and its upper swollen part is called thalamus. Bracts : It is a leaf like structure at the base of pedicel in whose axil a flower arises. The flower is described as bracteate when the bract is present. It is called ebracteate when the bract is absent. Symmetry : A flower may be symmetrical or asymmetrical. Asymmetrical

Symmetrical

Flowers which cannot be divided into equal halves by any radial plane are said to be asymmetrical, e.g., Cassia, Canna, etc.

A symmetrical flower can be cut into two equal halves radially. Such flowers are of two types

Actinomorphic

Flower are radially symmetrical i.e., divisible into two equal halves by any radial plane.



Zygomorphic

Flower are bilaterally symmetrical i.e., divisible into two equal halves by a single vertical plane.

Sex : On the basis of sex, the flowers are divided into three categories :

 Smallest Flower : Wolffia (Duck weed).  Largest Flower : Rafflesia arnoldi (1 m diameter)  Edible Style and Stigma : Crocus (Kesar).

182

BIOLOGY •

• •

Unisexual : When the flowers possess only one essential whorl, they are unisexual. They may be staminate (male) or pistillate (female). The unisexual plants are of two types : (i) Monoecious : When staminate and pistillate flowers are borne on the same plant, the condition is described as monoecious e.g., Cucurbitaceae. (ii) Dioecious : When staminate and pistillate flowers are borne on different plants, the condition is described as dioecious, e.g., Morus, Carica, Borassus. Bisexual : When both the essential whorls are present in the same flower, it is described as bisexual e.g., Cruciferae, Malvaceae etc. Polygamous : When some flowers are unisexual and some bisexual, they are collectively described as polygamous.

Position of the Flower : 

There are three possibilities about the position (attachment) of the floral whorls with respect to the ovary: Hypogynous When the calyx, corolla and androecium arise below the o v a r y, t h e f l o w e r i s described as hypogynous. The ovary thus becomes superior, e.g., Cruciferae, Liliaceae.

Epigynous

Perigynous When the sepal, petals and stamens appear to be arising from middle of the ovary, the flower is descried as perigynous. In these flowers, the ovary is semi-inferior, e.g., Saxifraga.

When the sepals, petals and stamens appear to be arising from the top of the ovary, the flower is described as epigynous. In these flowers, the ovary is inferior, e.g., Myrtaceae, (Callistemon), Umbelliferae ( Coriandrum ), Compositae, Cucurbitaceae, etc.

Corolla

Fig. 5.53 (a) Hypognous, (b) Perigynous and (c) Epigynous

Parts of flower An angiospermic flower is consists of two whorls of accessory or helping structure (Calyx and Corolla) and two whorls of reproductive or essential organs (androecium and gynoecium). Calyx

 Coloured sepals known as petaloid  are present in garden nasturtium. In dicotyledons usually the number of sepals is five and in monocotyledons usually three.

The outermost non-essential but protective whorl of the flower is the calyx. It is represented by the sepals. There are two conditions regarding calyx. Polysepalous Sepals are free.

Gamosepalous Sepals are wholly or partially united.

Corolla





The corolla constitutes the second or inner nonessential attractive whorl of the flower. It consists of petals which are variously coloured. The bright colour of the petals combined with the scent of essential oils present in some flowers make them highly attractive to insects which act as agents for pollination. It is polypetalous, if the petals are free and gamopetalous, if there is any degree of cohesion.

a

gm

Sti

Style

Anther Filam ent

Pistil



Stamen

Connecting Concepts

Ovary Petal

Locule

Sepal Ovule Placenta

Thalamus Pedicel

Fig. 5.54 A flower in L.S., showing position of different whorls on thalamus

MORPHOLOGY OF FLOWERING PLANTS

183

Perianth 

When there is no distinction between calyx and corolla, the whorl is described as perianth. It consists tepals (e.g., lily flower)..

Aestivation 

It is the arrangement of sepals/petals in relation to one another in a floral buds. It is four types: •

Valvate : Sepals/petals meet by their edges but don’t overlap.

•

Twisted : Sepals/petals overlap one another.

•

Imbricate : One sepal/petal completely external, one is completely internal and rest overlap one another.

•

Quincuncial : In this case, 2 sepals/ petals are external, two internal and rest overlap one other.

•

Vexillary : Butterfly shaped corolla consists of 5 petals. Odd posterior petal is called as standard. It is largest and outermost. It overlaps a pair of smaller lateral petals called wings or alae. Alae in turn overlap a boat shaped keel or carina.

Androecium  

It constitutes the third whorl of the flower. It is the male reproductive organ consisting of stamen. Each stamen is distinguishable into anther and filament joined by a connective. Each anther consists of two anther lobes and each lobe contains two pollensacs. The pollen grains are produced in pollensac.

Fusion of stamen

C

B

A D

E

Fig. 5.55 Types of Aestivation: (A) Valvate, (B) Twisted,

Fusion of stamen may be of following types : (a) Monadelphous stamens : When all the filaments are united into a single bundle but anthers are free, e.g., china rose. (b) Diadelphous stamens : When the filaments are united in two bundles and the anthers remain free, e.g., pea, bean, gram. (c) Polyadelphous stamens : When the filaments are united into more than two bundles but anthers are free, e.g., castor ((Ricinus), lemon (Citrus). (d) Syngenesious stamens : When the anthers are united into a bundle but the filaments are free, e.g., sunflower. (e) Synandrous stamens : When anthers as well as filaments of stamens are united throughout their whole length, e.g., Colocasia and most Cucurbits.

B

C

D

A

E Fig. 5.56 Cohesion of stamens

A. Monadelphous, B. Diadelphous, C. Polyadelphous, D. Synandrous, E. Syngenesious

(C) Imbricate, (D) Quincuncial, (E) Vexillary

184

BIOLOGY Adhesion 

Fusion among members of different whorls is described as adhesion. It may be epipetalous (fusion of stamens with petals), epiphyllous (stamens are fused with tepals).



Ocimum (labiatae) has four stamens, two of the which are long and two short. This condition is called didynamous condition. In cruciferae family, e.g., mustard, radish, etc., of the six stamens four are longer and in inner whorls and two in outer whorl are shorter, condition is known as tetradynamous condition.

Gynoecium It is the female reprod reproductive part of the flower. It constitutes the inner essential whorl of the flower comprising carpels.



It is distinguishable into a basal ovule bearing region (ovary), a terminal pollen receiving region (stigma), joined by a style.

om



.c

Placentation

The ovules are attached on the inner surface of the ovary walls on one or more cushions called placenta. The manner of arrangement of placentae inside the ovary is called placentation. Differents kinds of placentation are as follows :

sp

ot



Marginal : Single chambered ovary ovule are borne on margin on it, as in Pea (Leguminosae).

•

Parietal : Single chambered ovary ovules are borne on periphery as in Cruciferae family.

•

Axile : Several chambered ovary having placenta on the central axis. Ovules are attached to it as in China rose.

•

Free-Central: The ovary is one-chambered. The placenta arises from the base of the ovary in the form of a swollen central axis. The ovules are borne all over the surface of the placenta, as in Primulaceae, (e.g. Dianthus and Primrose).

ac

ad

em

y.

bl

og

•

Basal: The ovary is one chambered. The placenta is very small and arises directly

al

•

//n

ee tm ed

ic

on the thalamus. Only one ovule is borne at the base of the ovary, as in sunflower, marigold (compositae). Ovary wall Dorsal suture Locule Ventral suture Placenta Placenta Central Ovule axis

s:

B

tp ht

Ovule

Locule

Locule

Locule

Ovule

Ovule

D

C

Ovary wall

Ovary wall

A

Septum

Placenta

Septum

Central axis

Ovules E

F

Fig. 5.57 Different types of placentations A. Marginal (L.S), B. Parietal, C. Axile, D. Free central, E. Basal, F. SuperficialTHEFRUIT

MORPHOLOGY OF FLOWERING PLANTS

185

Fruit is a mature or ripened ovary, developed after fertilization. There is a dual effect of fertilization on ovary. After syngamy ovule is changed into the seed and after ripening succulent parenchyma and ovary wall is changed into the pericarp. The pericarp may be dry or fleshy. It is differentiated into outer epicarp, middle mesocarp and inner endocarp.

  



The fruit is very useful for plants as it protects the seeds and helps in the dispersal of seeds.



If fruit is developed from the ovary, the fruit is known as the true fruit.



But sometimes some other floral parts participate in the formation of fruit, such fruits are known as false fruits, e.g., thalamus in apple is modified to form fruit.

Hipanthium

Amphisarca Caryopsis Capsule

Double samara

Carcerulus Cypsella Silicula

Balausta

Regma Samara Siliqua

Hesperidium

Cremocarp Nut Follicle

Pepo

Etaerio of drupes Berry Lomentum

Schizocarpic (Splitting) Indehiscent (Achenial) Dehiscent (Capsular)

Dry

Achene

Drupe

Etaerio of berries

Etaerio of achenes Pome Succulent (or fleshy)

Legume or pod

Sorosis Etaerio of follicles

II. Aggregate fruits (Etaerio) I. Simple fruit

Classification of Fruits

Syconus

If a fruit is formed without fertilization of the ovary, it is called a parthenocarpic fruit.

III. Composite fruits (Multiple)



186

BIOLOGY

Classification of Fruits Morphologically fruits are classified as I. Simple fruits : These fruits develop from monocarpellary ovary or multicarpellary syncarpous ovary. II. Aggregate fruits (Etaerio) : These fruits develop from the multicarpellary apocarpous ovary. III. Composite fruits (Multiple): These fruits develop from the complete inflorescence.

I. Simple Fruits Persistent Calyx Pericarp

These fruits can be divided into two types : 1. Dry fruits : In these fruits pericarp is not distinguished into three layers. Stalk 2. Succulent fruits (Fleshy fruits) : In these fruits, pericarp is generally distinguished into Seeds three layers, epicarp, mesocarp and endocarp. Mesocarp is fleshy or fibrous. 1.

Fig. 5.58 Legume of Pea

Dry fruits Dry fruits are divided into the following three groups : (A) Dehiscent fruits (Capsular fruits) : In these fruits, the pericarp bursts automatically after ripening and seeds get dispersed. (B) Indehiscent fruits (Achenial fruits) : These fruits do not dehisce after ripening and seeds remain inside the pericarp. (C) Schizocarpic fruits (Splitting fruits) : These fruits, after ripening are divided into one seeded segment, but these segments do not rupture further. In this way this group of fruits is intermediate between dehiscent and indehiscent fruits.

(A) Dehiscent or Capsular Fruits : Hairy seeds Ventral suture Fig. 5.59 Follicle of Madar

Pericarp

Seeds

Replum

m

a

Fig. 5.60 Siliqua of Mustard

They are simple, dry, multi-seeded dehiscent fruits. Depending upon the mode of dehiscence, capsular fruits are of five types – pod, follicle, siliqua, silicula and capsule. 1. Pod or Legume : It is multi-seeded, unilocular fruit derived from superior monocarpellary pistil having marginal placentation. At maturity the fruit dehisces by both dorsal (non-seed bearing) and ventral (seed bearing) sutures e.g., pea, bean. 2. Follicle : It is similar to legume in being multi-seeded, simple, unilocular, dry fruit formed from superior monocarpellary pistil having marginal placentation. The mature fruit splits up by one suture only e.g., larkspur. The dehiscent suture may be ventral or dorsal. 3. Siliqua : It is a bilocular, simple dry multi-seeded fruit which develops from a bicarpellary pistil having parietal placentation and a false septum or replum between the two placentae. At maturity, fruit dehisces by both the sutures into two valves which spread outwardly from base to the apex. It exposes the replum bearing the attached seeds, e.g., mustard. 4. Silicula : The dehiscent fruit is similar to siliqua but is few seeded, short and flat. At maturity the fruit wall breaks open to form two valves for exposing the replum bearing the seeds, e.g., Iberis amaria (Candytuft), Capsella bursa-pastoris, (Shephard’s Purse). Midrib ig

Valves

St

Valves

Pericarp

Seeds Pericarp

Pedicel

Per sis caly tent x Pedicel

Rectum Sepal Fig. 5.61 Silicula of Capsella

Pedicel Fig. 5.62 Capsule fruits : (i) Bhindi (ii) Datura

5.

Capsule : It is a simple, dry multi seeded dehiscent fruit which dehisces by methods other than the ones found in legume, follicle, silicula. etc., Antirrhinum, poppy, cotton (Gossypium), ), lady’s Finger ((Abelmoschus), Datura.

MORPHOLOGY OF FLOWERING PLANTS 2. (i)

187

Succulent or Fleshy Fruits Succulent fruits can be divided into the following types : Pome : • It is a false fruit as it, develops from the fleshy thalamus. True fruit remains inside the swollen thalamus. • Fleshy swollen thalamus of these fruits is the edible e.g., Pyrus malus (apple), Pyrus communis (pear) and Eriobotrya japonica (lokat).

Fig. 5.63 Pome of Apple (i) L.S.

(ii)

Drupe (Stony fruits) : • These fruits develop from mono or multicarpellary, syncarpous, superior ovary. These fruits are having one or many seeded. • Epicarp of these fruits forms the rind of fruits. Mesocarp is fleshy or fibrous and endocarp is hard and stony. • In Mangifera indica (mango), peach and cherry the fleshy mesocarp is the edible. • In coconut, mesocarp is fibrous which forms the coir on drying, seed and oily endosperm are the edible part. • In almond and walnut the edible part is seed especially its cotyledons.

Fig. 5.64 Drupe (i) Mango (ii) Peach

(iii) Berry : • These fruits develop from mono or multicarpellary, syncarpous ovary. Ovary is superior and sometimes inferior. • Placement is axile or parietal. • Epicarp in these fruits makes the ring of fruit. Mesocarp is fleshy and endocarp is thin like a membrane, e.g., tomato, papaya, cheeku, Areca catechu (Areca nut = Areca palm = Supari) brinjal, Psidium guajava, banana, date palm, grape. Date palm, and Areca catechu (areca nut) are single seeded berry. Epicarp

Epicarp

Seeds Mesocarp Endocarp Seeds (i)

(ii) Fig. 5.65 Berry - (i) Tomato (ii) Papaya

188

BIOLOGY Placenta

Seeds Epicarp Mesocarp Endocarp Central cavity Rind

Fig. 5.66 Pepo in Cucurbits

Hard persistent calyx Pericarp

(iv) Pepo : • These fruits resemble berries, but these develop from inferior ovary with parietal placentation. • Epicarp makes a hard rind. • This type of fruits is specially found in family Cucurbitaceae, e.g., Bottle gourd, Cucumis sativus (Cucumber), Cucumis melo (Muskmelon). (v) Hesperidium : • These fruits develop from multicarpellary, syncarpous, superior ovary having axile placentation. • Many oil glands are present in the epicarp. Mesocarp is in the form of white, fibrous part fused with epicarp. Membranous endocarp forms distinct chambers. Many edible unicellular juicy hairs are present on the inner side of endocarp. • All citrus fruits are hesperidium e.g., Orange, Lemon.

Juicy testa of seeds Fig. 5.68 Balausta of pomegranate

Seeds

Fig. 5.69 Hesperidium of orange (i) T.S

Hard pericarp

Fig. 5.60 Amphisarca of wood apple

(iv) Balausta : • These fruits develops from multilocular, syncarpous, inferior ovary. • Testa (outer covering of the seed) is fleshy and edible. Tegmen (inner convering of the seed) is hard. • Seeds are dispersed in the fruit. Pericarp is rough and leathery e.g., Pomegranate. (vii) Amphisarca : • These fruit develops from multicarpellary, syncarpous, multi-chambered superior ovary. • Epicarp is hard. Mesocarp and endocarp are fleshy having seeds. Mesocarp, endocarp and swollen placenta are eaten, i.e., Aegle marmelos (Wood apple). (viii) Hipanthium : • It is a false fruit as the edible part is fleshy thalamus but it differs from pome, as it develops from a multicarpellary, apocarpous, semi-inferior ovary e.g., Rose.

Aggregate Fruits (Etaerio) Fruitlets (Follicles) Fig. 5.61 Etaerio of follicles in Michelia

(i)

On the basis of the nature of individual fruitlet the aggregate fruits are of the following types : Etaerio of follicles : • In such fruits, each carpel develops into a fruitlet which is known as follicle. •

Achenes

Many follicles (fruitlets) make an etaerio which are arranged on the enlarged thalamus in a bunch, e.g., etaerio developed from two follicles. Calotropis and Catharanthus (Vinca).

• Etaerio developed from many follicles, e.g., Michelia. (ii) Etaerio of achenes : • Each fruitlet is an achene, e.g., Narvelia, Clematis. • Spongy thalamus Fig. 5.70 Etaerio of achenes in lotus

Achenes are hairy. In Rose, many achenes are present on a saucer (cup) like thalamus. In Lotus, thalamus becomes spongy and some achenes are embedded in it.

•

The thalamus is fleshy and becomes red on maturation and is the edible part in Strawberry.

MORPHOLOGY OF FLOWERING PLANTS

189

(iii) Etaerio of berries : •

It is an aggregate fruit consist of small berries e.g., in custard apple, many berries are developed on fleshy thalamus.

Thalamus Seed Mesocarp

Apical parts of berries fuse with each other and make a common rind, e.g., Polyalthea, Anona squamosa (Custard apple, Sharifa). (iv) Etaerio of drupes : •

•

In this type of fruit, many small drupes, developed from different carpels are arranged collectively (in groups) on the fleshy thalamus, e.g., Rubus idaeus (Raspberry). A drupelet

Fruitlets Fig. 5.71 Etaerio of berries in Anona squamosa

Thalamus Seed Persistent calyx (i)

(ii)

Fig. 5.72 (i) Etaerio of drupes in Rubus, (ii) L.S. of the etaerio

Crown of scale leaves

Composite Fruits (Multiple Fruits) These fr fruits develop from the whole inflorescence. They are of two types : (i) Sorosis : These fruits develop from spike, spadix or catkin inflorescence. In Artocarpus integrifolia (Jack fruit = Kathal) pistillate flowers are developed very close to each other around the rachis. Bracts, perianth and seeds become succulent and are used for eating. In Ananas sativus (Pine apple) too, rachis, bracts and perianth are the edible parts. In Morus alba (Mulberry) fleshy perianth present around the dry achenes is eaten up. (ii) Syconus : It develops from hypanthodium infloresence. Receptacle becomes fleshy and many achenes develop from the pistillate flowers. Rachis (Fleshy receptacle) of these fruits is edible part, e.g., Ficus carica (Fig = Anjeer). Fig. 5.73 Sorosis

Female flower

Gall flower

Male flower

Fig. 5.74 Syconus of Ficus carica L.S. of fruit and three types of flowers

Indehiscent or Achenial Fruits These fruits develop from single ovuled ovary having basal placentation, and so are single seeded. (i) Achene : These fruits develop from monocarpellary superior ovary. These fruits are unilocular and one seeded and pericarp is free from the seed coat. e.g., Ranunculus species, Clematis gouriana, Naravelia zeyliana. (ii) Nut : These fruits are also unilocular and one seeded and these are developed from bi-or multicarpellary syncarpous, superior ovary. Pericarp in these fruits becomes hard and stony, e.g., Litchi chinensis, Anacardium (Cashew nut), Oak, Trapa bispinosa. In Litchi the single seed is covered by a white transluscent fleshy and edible aril.

Fig. 5.75 Achene of Naravelia

190

BIOLOGY Pericarp Oil duct Cotyledon Radicle

Stalk Leathery pericarp Seed

Swollen fruit stalk

Fleshy aril

Leathery pericarp

(i)

(ii)

Fig. 5.76 Nuts (i) Litchi (ii) Anacardium (cashew nut)

(iii) Samara : Pericarp of these fruits becomes flat like wings and thus help in the dispersal of fruits by wind, e.g., Holoptelea indica (Chilbi). In some fruits, the calyx becomes wing like. Such samara like fruits are termed as samaroid e.g. Hopea, Sal (Shorea robusta). Pedicel Winged Pericarp

Hairy pappus

Seed

(i)

(ii) Fig. 5.77 Samara of Holoptelea

Fig. 5.78 Cypsela

(iv) Cypsela : These fruits develop from bicarpellary, syncarpous, inferior ovary. These are unilocular and one seeded. Pericarp is free from the seed coat. Persistent hairy calyx called ‘pappus’ are attached with the fruits. Pappus helps in parachute mechanism for fruit dispersal by wind. It is usually present in family Compositae, e.g., Helianthus annus (Sunflower), Tagetes erects (Marigold), Cosmos, Taraxacum. (v) Caryopsis : These fruits develop from monocarpellary, superior ovary. These fruits are unilocular and one-seeded. Pericarp of these fruits is inseparably fused with the seed coat. These fruits are present in family Gramineae, e.g., Wheat, Rice, Maize. So the grains of these plants are not seeds but in reality the fruits. This is considered as most advanced kind of dry fruit. Style

Remnants of style

Embryo

Starchy endosperm Aleurone layer

Base of style

Seed and fruit coverings Epithelium Coleoptile Plumule Radicle

Spathe

Endosperm (ii)

Coleorhiza Scutellum (Cotyledon) Kernel stalk

(iii)

(i) Fig. 5.79 Maize (i) Cob of Maize, (ii) Single grain (Caryopsis) of Maize (iii) L.S. of Maize grain

MORPHOLOGY OF FLOWERING PLANTS Fruits Apple, Pear Banana Cashewnut Coconut Cucumber Date palm Fig Jack fruit Grapes Guava Litchi Wheat, maize Mango Pea, Gram Orange, Papaya Pineapple Pomegranate Tomato Mustard

Type Pome Berry Nut Drupe Pepo Berry Synconus Sorosis Berry Berry Nut Caryopsis Drupe Legume Hesperidium Berry Sorosis Balausta Berry Siliqua

191 Edible Parts Fleshy thalamus Mesocarp Cotyledons, fleshy thalamus Endosperm Mesocarp, endocarp, seeds Pericarp Thalamus Bracts, perianth & seeds Pericarp and placenta Thalamus and pericarp Aril Endosperm Mesocarp Cotyledons Juicy placentae Mesocarp Bracts, receptacle Seed coat Pericarp and placentae Seed

THE SEED          

Connecting Concepts

Seed is the ripened ovule which contains an integumented embryo or miniature plant with adequate reserve food for future development of the embryo. Seeds are the characteristic feature of spermatophytes (Gymnosperms and Angiosperms) A seed may have one or two coverings called seed coats develops from integuments of oracle. The outer seed coat is called testa, while the inner one is named as tegmen. The surface of the seed possesses a fine pore at one end is called micropyle. The testa ensures survival of seeds. The micropyle of ovule permits the entry of water needed at the time of germination. Just behind the micropyle hilum is present. It is a scar left on the seed coat when it is detached from the fruit wall. With in the seed coat there is the embryo, consisting of an embryonal axis and two cotyledons. The cotyledons are often fleshy and full of reserve food materials. At the micropylar end of the embryonal axis, bears the radicle and the other end contains plumule are present. In some seeds such as castor, the endosperm is persistent which formed as a result of double fertilisation. Endosperm is a food storing tissue. There are two types of seeds i.e., albuminous and exalbuminous. • Albuminous (endospermic) seeds : In these seeds food is stored in the endosperm., e.g., corn, wheat, castor, onions, etc. • Exalbuminous (non-endospermic) seeds : They usually store reserve food material in cotyledons. In these seeds, the endosperm is used up and not present in mature seeds, e.g., bean, gram and pea. Seed coat

Cotyledon Plumule

Hilum Radicle Micropyle

Fig. 5.80 Seed and structure of dicotylendonous seed

 Spermology : Study of Seeds.  Smallest and Lightest Seed : Orchids with 0.004 mg weight  Largest and Heaviest Seed : Lodacea moildivica (Double Coconut) with 6 kg weight  Dicot Seed Without Cotyledons : Cuscuta.

192

BIOLOGY

Structure of Monocotyledonous seed 

The maize grain shows structure of a typical monocotyledonous seeds. In maize grain the seed coat is fused with the pericarp.



The major part of the grain is occupied by a large endosperm which is rich in starch.



The endosperm has one to three layered peripheral protein layer called aleurone layer which separates the embryo with endosperm. The embryo consists of a cotyledon and an embryonal axis. The cotyledon is also called scutellum in cereals. It is laterally attached to the embryonal axis.



The lower end of the axis is called the radicle which has a protective sheath termed coleorhiza.



The upper end of the axis is called the plumule which is covered by coleoptile.

Fig. 5.81 Structure of a monocotylendous seed

Structure of Dicotyledonous seed 

A dicotyledonous seed contains the seed coats, two cotyledons and an embryonal axis



The embryonal axis is attached to the cotyledons for absorbing nutrition from them.



The embryonal axis consists of two ends- the radicle and plumule. The former gives rise to root system and later to the shoot system.



The portion of embryonal axis between the radicle and the point of attachment of the cotyledons is called hypocotyl, whereas the portion between the plumule and cotyledon is called the epicotyl.



Most of the dicotyledonous seeds are exalbuminous.



They lack endosperm at maturity since their endosperm is consumed by the developing cotyledons.



A few dicotyledons like castor, bean and rubber have albuminous seeds. Their cotyledons are thin and papery.

SEMITECHNICAL DESCRIPTION OF A TYPICAL FLOWERING PLANTS Symbols For Floral Formula (A) Bracts (Br) Br

Bracteate

Ebr

Ebracteate

(B)

Symmetry of the flower

⊕

Actinomorphic

% or

Zygomorphic

(C)

Sex

MORPHOLOGY OF FLOWERING PLANTS Staminate (male) Pistillate (female) Hermaphrodite (D)

Calyx (K)

K4

4 sepals, polysepalous (Sepals free)

K(4)

4 sepals, gamosepalous (Sepals fused)

(E)

Corolla (C)

C4

4 petals, polypetalous

K2+2

4 sepals in 2 whorls of 2 each

C(4)

4 petals, gamopetalous

(F)

Perianth (P)

P6

6 tepals, polytepalous

P(3)+(3)

6 tepals, gamotepalous

(G)

Androecium (A)

A6

6 stamens, polyandrous

A0 A∝ A10 A1+(9)

Stamens absent Stamens indefinite Stamens 10, monoadelphous Stamens 10, diadelphous

C2+2

P3+3

A2+4

4 petals in 2 whorl of 2 each

6 tepals, in 2 whorls of 3 each

6 stamens in 2 whorls of 2 and 4 each

Epipetalous Epiphyllous (H) Gynoecium (G) G0 Gynoecium absent G2 2 carpels, apocarpous G(2) 2 carpels, syncarpous G(2–) Bicarpellary, syncarpous, inferior G(2) Bicarpellary, syncarpous, superior  Apocarpous : Gynoecium consisting of two to many free carpels. Each carpel forms its own pistil.  Syncarpous : Gynoecium consisting of two to many carpels fused laterally forming a compound pistil.

Description of Some Important Families

FABACEAE OR LEGUMINOSAE It is commonly called as pulses family. It is 4th largest (after compositae, orchidaceae and gramineae) and 2nd most valuable (after gramineae) family of plant kingdom that provides maximum timber. Habit – Annual or biennial, herb, shrub or tree. Root – Tap root system. Stem – Erect or creeping, solid or weak. Leaf – Alternate or whorled, stipulate, compound, reticulate venation. This family is subdivided into three subfamilies.

193

194

BIOLOGY Characters

Papilionaceae

1. Habit Mostly herbs 2. Inflorescence Generally raceme or panicle. 3. Flower Bracteate, bracteolate, zygomorphic, hermaphrodite, pentamerous and hypogynous. 4. Calyx Sepals 5, gamosepalous, valvate or imbricate, odd sepal anterior. 5. Androecium Stamens 10, usually diadelphous (9) + 1or (5+5), monadelphous (10 or 9) (Crotolaria), anthers dithecous, introrse. 6. Gynoecium Monocarpellary, superior ovary unilocular with marginal placentation 7. Fruit Legume

Connecting Concepts

8. Floral Formula

Br.  + 2 + (2)

Caesalpiniaceae

Mimosaceae

Shrubs Generally raceme or panicle. Bracteate, zygomorphic, hermaphrodite, pentamerous, hypogynous.

Trees Globose head or spike.

Sepals 5, polysepalous or gamosepalous, imbricate or valvate, odd sepal anterior. Stamens 18, 5+5, polyandrous, 4 + 3 stamens fertile, 3 staminodes, anther dithecous, introrse.

Sepals 5 or 4 gamopetalous, valvate, odd petal posterior.

Same as Papilionaceae.

Same as Papilionaceae.

Legume or Lomentum.

Lomentum ((Acacia)

Bracteate, sessile, actinomorphic, hermaphrodite, pentamerous, hypogynous.

Stamens indefinite, polyandrous ((Acacia) or monadelphous anthers dithecous, introrse.

K5 or (5) C1 Br.  K5 or (5) C5 A1 + (9) G1 A10 or 5 + 5 G1.

 The main characters of Leguminosae or fabaceae family are : 9. Floral Figure  Polypetalous condition.  Single carpel condition).

(monocarpellary

 Perigynous condition and marginal placentation.

Fig. 5.82 Floral Diagram of Pisum sativum (Garden pea)

Fig. 5.83 Floral Diagram of Cassia fistula (Amaltas)

Fig. 5.84 Floral Diagram of Acacia arabica (Kiker)

Economic Importance of Papilionaceae family Plants used as food :  Pulses—Various kinds of pulses are obtained from the plants of this family e.g., garden pea—edible pea (Pisum sativum), chick pea or gram (Cicer arietinum), Lobia (Vigna inensis), Arhar (Cajanus cajan), Masoor (Lens esculenta), Urd (Phaseolus mungo), Mung (P. aureus).  Pulses are rich in proteins that contain all amino acids but poor in methionine, lysine and tryptophan. It also provides fodder, fibre, timber and oil.  Ground nut (Arachis hypogea)—Its embryo is used in preparation of vegetable oil. Soyabean (Glycine max)—It is rich in protein.  Sesbania, Trifolium is used as fodder. 

Sem (Dolichos lablab), Lobia (Vigna sinensis), Pea (Pisum sativum) are used as vegetables. Leaves of Trigonella are also used as vegetable.

MORPHOLOGY OF FLOWERING PLANTS Plants used in medicines :  Roots of Glycyrrhiza glabra (liquorice = mulaithi) are used in sore throat.  Glycyrrhizin, a glycoside in root, is 50 times sweeter than sugar. Seeds of Psoralea corylifolia (Babchi/khatmi) are used in leucoderma.  Gangetium—Roots are used in diarrhoea, cough.  Clitoria ternata ternata—Leaves and flowers are used in snake bite.  Desmodium asthma, snake and scorpion bite. Soil fertility : Roots of plants of this family are nodulated that contain nitrogen fixing bacteria Rhizobium.  Crotolaria, Sesbania, Cyamopsis are used as green manure. Sesbania rostrata contain two nitrogen fixing bacteria i.e., Rhizobium in root nodules and Aerorhizobium in their stem nodules. Fibre yielding plants : The secondary phloem of stem of Crotolaria juncea (sun hemp) provides fibre. Ornamental plants :  Sesbania grandiflora  Butea monosperma : These plants are having deep red flower known as fire of the forest.  Lathyrus odoratus (sweet pea-wild pea) : These plants are having variously coloured flowers. Miscellaneous uses : (i) Crotolaria juncea (Sun hemp) : Fibres from phloem and pericycle of stem (bast fibres) are obtained, used for making ropes, mats, etc. It is also important ‘Green manure’ crop. (ii) Indigofera tinctoria (Indigo or Neel) : Indigo dye used in dyeing and printing cotton, is obtained from this plant. (iii) Astragalus gummifer : ‘Gum tragacanth’, which is commercially used as emulsifier, in cosmetics, in confectionary and in textile industry. (iv) Desmodium gyrans (Indian Telegraph plant): The plant shows spontaneous leaf movement. (v) Abrus precatorius : Seeds of this plant are Jewellers for weighing purpose. Each seed is having constant weight of 1.75 grains. Leaf juice is used for cure of leucoderma (skin disease).

Economic Importance of Caesalpiniaceae family (I) Food plants (i) Bauhinia variegata (Kachnar) : Flower buds are used as vegetable. (ii) Tamarindus indica (Imli) : The fruits are used as condiment. (II) Medicinal plants Cassia fistula (Senna or Amaltas) : The pulp of fruits as well as leaves are laxative and hence used in ‘churns’. (ii) Saraca indica (Ashok) : One of the most sacred trees of India and its bark is used in troubles of manstruation. (III) Ornamental plants: (i)

(i) Cassia fistula (Amaltas)-Beautiful yellow flowers. (ii) Delonix regia (Gulmohar)-Scarlet flowers. (iii) Saraca indica (Ashok or Sita Ashok) – Orange flowers used for decoration of temples. (iv) Parkinsonia aculeata (Vilayati Kiker) – Fragrant yellow flowers are grown on road sides, railway platforms, etc. as ornamental plant. (IV) Others (i) Caesalpinia sappan (Sappan) : Heart wood of this provides a red orange dye, which is source of ‘Gulal’ used in Holi festival. (ii) Haematoxylon campechianum (Log wood) : A dye called haematoxylin is obtained from wood of this plant, which is used as a stain in anatomical preparation.)

195

196

BIOLOGY (V) Economic importance of Mimosaceae Family Important plants of this family as well as their uses are : 1. Acacia arabica (Kiker or Babool)– ‘Gum arabic’ is obtained from its bark. Tannin is also obtained from its bark. 2. Acacia catechu (Kattha)– ‘Kattha’ is obtained from its wood. Lac insects survive on this plant. 3. Albizzia lebbek (Siris)–A special type of gum called ‘Sresh’ is obtained from the bark. 4. Pithcolobium dulce (Ingadulce of Jangal jalebi or Raintree)–Hedge plant. Juicy aril surrounding the seed is edible. 5. Mimosa pudlca (Touch me not or chui-mui)–Shows seismonastic movements. 6. Leucaena leucophloea (White popinae)–This tree is grown under social forestry nowadays.

SOLANACEAE 

It is a large family commonly called as ‘potato family’.

Vegetative characters : 

Plants mostly, herbs, shrubs and small trees.



Stem : herbaceous rarely woody, aerial; erect, cylindrical, branched, solid or hollow, hairy or glabrous, underground stem in potato (Solanum tuberosum).



Leaves : alternate, simple, rarely pinnately compound, exstipulate; venation reticulate.

Floral characters : 

Inflorescence – Axillary, solitary or cymose in Datura.



Flower – Ebracteate, actinomorphic, hermaphrodite, pentamerous and hypogynous.



Calyx – Sepals 5, gamosepalous, valvate, persistent.



Corolla – Petals 5, gamopetalous, valvate or twisted.



Androecium – Stamens 5, epipetalous anthers.



Gynoecium – Bicarpellary, syncarpous, ovary superior, bilocular, many ovules in each locule.



Fruit – Generally berry, capsule in Datura.



Floral Formula – EBr.⊕



Floral diagram.

Fig. 5.85 Floral diagram

Connecting Concepts

K(5)

G(2)

Economic Importance

 Distinguishing features of solanaceae (i) family

(ii)  Petioles of leaves attached to stem (iii) for some distance. (iv)  Generally 5,persistant sepals. (v)

Solanum tuberosum (Potato) : Most important stem vegetable (tubers) in the world. Solanum melongena (Egg plant or Brinjal) : Fruits are source of vegetable. Lycopersicon esculentum (Tomato) : Fruits are source of vegetable and salad. Capsicum annuum (Chillies or Red Pepper) : Fruits are source of spices. C. frutescens (Shimla Mirch): Fruits are used as vegetable.

 5 stamens having filaments of Medicinal plants unequal lengths.  Ovary obliquely placed with swollen (i) placenta.

Atropa belladona : Alkaloid atropine is extracted from the roots forms belladona drug. (ii) Datura stramonium : Alkaloids atropine, hyoscyamine and hyocine and drug stramonium is obtained from dried leaves used in the treatment of asthma. Seeds of this plant is deadly poisonous. (iii) Hyoscyamus niger (Henbane) : Dried leaves and flowering tops yield drug henbane which is used in treatment of asthama and whooping cough.

MORPHOLOGY OF FLOWERING PLANTS

197

(iv) Withania somnifera : Drug Agandh used in rheumatism, female troubles and cough are obtained from the root of this plant. (v) Nicotiana tabacum (tobacco) : Alkaloid nicotine extracted from this plant which is used as antispasmodic sedative. Fermented leaves of this plant are source of tobacco used for smoking, chewing and snuffing. Its seeds provide oil, which is used in paints and varnishes. Ornamental plants : (i) Petunia alba, P. hybrida : Flowers of different colours like white, pink, etc. (ii) Cestrum nocturnum (Night Jasmine or Rat Ki Rani) (iii) C. diurnum (Day Jasmine or Din Ka Raja) (iv) Nicotiana alata. (v) Brunfelsia hopeana (Yesterday, today, tomorrow plant) (vi) Schizanthus (Butterfly flower). (vii) Salpiglossis, etc. Others (i)

Solanum nigrum (Night shade plant or Makoa).

Floral diagram of solanum nigrum (Makai) :

 Distinguishing liliaceae family.

LILIACEAE It is commonly called as lily family. Habit—Usually perennial herb as Polygonatum, sometimes small shrubs as Ruscus. Root—Adventitious, fibrous. Stem—Erect or climbing as Smilax, branched or unbranched, herbaceous. Leaf— Exstipulate, alternate or whorled, parallel venation. Leaf Inflorescence—Raceme, umbel or sometimes solitary. Flower—Pedicellate, bracteate, hermaphrodite. actinomorphic, trimerous, hypogynous. Perianth— Six (3 + 3) perianth in two whorls, imbricate aestivation,. Androecium— Six (3 + 3) stamens in two whorls. Gynoecium—Tricarpellary, syncarpous, superior ovary, axile placentation, trilocular, two or more ovules in each locule. Fruit—Capsule or rarely berry. Floral formula — Br. ⊕

Connecting Concepts

 Plants herbs.

are

features generally

of

perennial

 Trimerous flowers.  6 tepals (units of perianth) in 2 whorls of 3 each.  6 stamens in 2 whorls of 3 each, antiphyllous, i.e., opposite the tepals.  Tricarpellary, syncarpous gynoecium, trilocular ovary with axile placentation.

P3 + 3 A 3 + 3 G(3)

Economic Importance Plants used as food : Allium cepa, A. sativum and Asparagus racemosus are used as vegetables. Plants used in medicines : Leaves of Allium cepa (onion) are used in dental and ear troubles. The leaves of Allium sativum (lahasun) are used in cough and fever. The leaf extract of Crinum latifolium (sukhdarshan) is used in ear pain. Bulb and leaf of Crinum asiaticum are used in urinary troubles. Aloe is also used in skin prolbem. Ornamental plants: Dracaena terniflora, Yucca spp. Lilium candidum, Gloriosa superba (Glory lily), etc. Other commercial uses : Colchicine, an alkaloid obtained from Colchicum autumnale is used to induce polyploidy in plants.

the

Fig. 5.86 Floral diagram

198

BIOLOGY

EXERCISE - 1 | NCERT BASED QUESTIONS 1.

2.

3.

4.

5.

6.

7.

8.

9.

Most plants are green in colour because (1) the atmosphere filters out all the colours of the visible light spectrum except green. (2) green light is the most effective wavelength region of the visible spectrum in sunlight for photosynthesis. (3) chlorophyll is least effective in absorbing green light. (4) green light allows maximum photosynthesis. Floral features are chiefly used in angiosperms identification because (1) flowers are of various colours. (2) flowers can be safely pressed. (3) reproductive parts are more stable and conservative than vegetative parts. (4) flowers are good materials for identification. In a cereal grain the single cotyledon of embryo is represented by (1) scutellum (2) plumule (3) coleoptile (4) coleorhiza Function of stem is (1) bearing leaves and branches (2) conduction of water & minerals (3) conduction and storage of food (4) All of the above Main function of leaf is (1) manufacture of food (2) exchange of gases (3) both 1 and 2 (4) none of the above Arrangement of leaves on a stem is (1) venation (2) vernation (3) inflorescence (4) phyllotaxy A modification of leaf is (1) phyllode (2) phylloclade (3) cladode (4) corm Pneumatophores are found in (1) the vegetation which is found in marshy and saline lake (2) the vegetation which found in saline soil (3) xerophytes (4) epiphytes Pulses yielding family of plants is (1) poaceae (Graminae) (2) cucurbitaceae (3) liliaceae (4) papilionaceae

10. Tetradyanamous conditions occur in (1) cruciferae (2) malvaceae (3) solanaceae (4) liliaceae 11. Occurrence of different types of leaves on the same plant is (1) heterophylly (2) heterotrophy (3) heteronasty (4) All of the above 12. A modification of bud that can bear leaves, flowers, fruits & branches is (1) thorn (2) spine (3) prickle (4) trichome 13. Flower is complete when it has (1) calyx, corolla, androecium & gynoecium (2) calyx & corolla (3) androecium & gynoecium (4) corolla, androecium & gynoecium 14. A plant with both male & female flowers is (1) monoecious (2) dioecious (3) unisexual (4) bisexual 15. Aleurone layer helps in (1) storage of food in endosperm (2) protection of embryo (3) utilization of stored food (4) All of the above 16. Choose the correct option for A, B and C.

(1) A - zone of elongation, B - zone of meiosis, C - zone of mitosis (2) A - zone of maturation, B - zone of meristematic activity, C - zone of elongation (3) A - zone of mitosis, B - zone of elongation, C - zone of root cap (4) A - region of maturation, B - region of elongation, C - meristematic activity

MORPHOLOGY OF FLOWERING PLANTS

199

17. Which one of the following option is incorrect?

21. Chosse the correct combinations.

(1) Tap roots of carrot, turnip and adventitious root of sweet potato, get swollen and store food. (2) Pneumatophores help to get oxygen for respiration. (3) Pneumatophore is found in the plants that grow in sandy soil. (4) A, B and C are underground roots but D grows vertically upwards. 18. Which of the following option is correct?

A

B

C

D

(1) Lamina Axillary bud Stipule Leaf base (2) Lamina Stipule Axillary bud Leaf base (3) Lamina Axillary bud Stipule Pedicel (4) Leaflet Axillary bud Stipule Leaf base 19. Choose the correct option for A and B.

(1) A-Cymose, B-Racemose (2) A-Racemose, B-Cymose (3) A- Racemose, B - Racemose (4) A- Cymose, B - Cymose 20. Which option is correctly matched with the diagrams?

(1) (2) (3) (4)

A-Valvate, B-Twisted, C-Imbricate, D-Vexillary A-Vexillary, B-Valvate, C-Twisted, D-Imbricate A-Imbricate, B-Vexillary, C-Valvate, D-Twisted A-Twisted, B-Imbricate, C-Vexillary, D-Valvate

I. Hypogynous flower II. Perigynous flower III. Epigynous flower (1) A-I, B-II, C-III (2) A-I, B-III, C-II (3) A-III, B-II, C-I (4) A-III, B-I, C-II 22. Which is the correct combination? Column I Column II Column III A.

Mariginal

I.

p. Sunflower, Marigold

B.

Axile

II.

q. Dianthus, Primrose

C.

Parietal

III.

r. Musatrd, Argemone

D.

Free Central IV.

s. China rose, Tomato, Lemon

E.

Basal

t. Pea

V.

(1) A- V, t; B -II, s; C -I, r; D -III, q; E -IV, p (2) A - I, t; B - II, s; C - III, r; D - IV, p; E - V, q (3) A - V, p; B - II, s; C - I, q; D - III, r; E - IV, t (4) A - V, p; B - III, q; C - II, s; D - I, t; E - IV, r 23. Choose the correct option for A and B.

(1) A - Pinnately compound leaf, B - Palmately compound leaf (2) A - Palmately compound leaf, B - Pinnately compound leaf (3) A- Pinnately compound leaf, B - Pinnately compound leaf (4) A - Palmately compound leaf, B - Palmately compound leaf

200

BIOLOGY

24. Identify the phyllotaxy.

27. Which one of the option is correct? Seed coat

C

Raphe A

D E

B Seed

(1) A - Hilum, B - Micropyle, C - Radicle, D - Cotyledon, E - Plumule

(1) A-Alternate, B - Opposite, C - Whorled (2) A- Whorled, B - Opposite, C -Alternate (3) A-Alternate, B - Whorled, C - Opposite (4) A-Whorled, B -Alternate, C - Opposite 25. Which one of the following option is correct?

(2) A - Hilum, B - Micropyle, C - Plumule, D - Cotyledon, E - Radicle (3) A - Micropyle, B - Hilum, C - Plumule, D - Cotyledon, E - Radicle

A

(4) A - Hilum, B - Micropyle, C - Plumule, D - Radicle, E - Cotyledon

Stigma Style

28. Identify A, B, C, D and E parts of a typical structure of monocotyledonous seeds.

Anther B

Seed opened

Ovary

Filament

Corolla-petals C Calyx-sepals

Pedicel

D

A (1)

Gynoecium

(2)

Gynoecium

B

C

D

Megasporophyll Ovule Thalamus Stamen

Seed

(3) Microsporophyll

Stamen

Ovule Thalamus

(4)

Stamen

Ovule Thalamus

Gynoecium

26. Choose the correct option.

Thalamus

(1) A- Endosperm, B - Embryo, C - Scutellum, D - Coleorrhiza, E - Coleoptile (2) A- Embryo, B - Endosperm, C - Scutellum, D - Coleoptile, E - Coleorrhiza (3) A - Endosperm, B - Embryo, C - Scutellum, D - Coleoptile, E - Coleorrhiza (4) A - Embryo, B - Endosperm, C - Scutellum, D - Coleorrhiza, E - Coleoptile 29. Which one is the correct answer for cohesion of stamens in the given diagram

(1) (2) (3) (4)

I II Epicarp, Mesocarp, Seed, Endocarp Epicarp, Mesocarp, Ovule, Endocarp Epicarp, Mesocarp, Ovary, Endocarp Epicarp, Mesocarp, Embryo, Endocarp

(1)

Monoadelphous

(2)

Diadelphous

(3)

Polyadelphous

(4)

Synandrous

MORPHOLOGY OF FLOWERING PLANTS

201

30. Which one is correct option for the species belong to given families respectively?

Pisum sativum (pea)

Solanum nigrum (makoi)

Allium cepa (onion)

(1) Liliaceae, Compositae, Malvaceae (2) Fabaceae, Solanaceae, Liliaceae (3) Compositae, Malvaceae, Liliaceae (4) Solanaceae, Fabaceae, Liliaceae 31. Matching the following and choose the correct option Column I Column II A. Bud in the I. Pitcher plant axil of leaf and Venus fly trap B. Outer layer of II. Cacti seed coat C. Spines III. Testa (modified leaves) D. Leaves modiied IV. Simple leaf to catch insects E. Fleshy leaves V. Garlic and onion with stored food (1) (2) (3) (4)

A

B

C

D

E

I V IV IV

II IV III II

III III II III

IV II I I

V I V V

32. Choose the correct combinations. Column I Column II A. Gamosepalous I. Flower of lily B. Polysepalous II. Sterile anther C. Gamopetalous III. Free petals D. Polypetalous IV. Free sepals E. Epiphyllous V. Fused petals F. Staminode VI. Fused sepals (1) (2) (3) (4)

33. Matching the following and choose the correct option. ColumnI Column II A. Coleorrhiza I. Grapes B. Food storing tissue II. Mango C. Parthenocarpic fruit III. Maize D. Single seeded fruit IV. Radicle developing from monocarpellary superior ovary E. Membranous seed coat V. Endosperm (1) A - III, B-I, C -IV, D - II, E - V (2) A - IV, B-II, C - V, D - I, E - III (3) A - V, B-I, C - III, D - IV, E - II (4) A - IV, B - V, C - I, D - II, E - III 34. Which is the correct combinations ? Column I Column II (Members of Fabaceae) (Economic importance) A. Gram, sem, moong, I. Medicine soyabean B. Soyabean,groundnut II. Ornamental C. Indigofera III. Fodder D. Sunhemp IV. Fibres E. Sesbania, Trifolium V. Dye F. Lupin, Sweet potato VI. Edible oil E. Mulaaithi VII. Pulses (1) A - I, B - II, C - III, D - IV, E - V, F - VI, G - VII (2) A-VII, B - VI, C - V, D -IV, E - III, F - II, G-I (3) A - II, B - IV, C - VI, D - I, E - III, F - V, G - VII (4) A - I, B - III, C - V, D - VII, E - II, F - IV, G - VI 35. Which of the following statement (s) is/are incorrect? I.

Calyx and corolla are reproductive organs of a flower.

II.

Zygomorphic flower can be divided into two equal radial halves in any radial plane.

III. Flowers without bracts are termed as bracteate. IV. Parthenocarpic fruit is formed after fertilization of the ovary.

A

B

C

D

E

F

V.

IV IV VI VI

V V IV IV

III III V V

I I III III

VI II I II

II VI II I

VI. Radical buds develop on roots. (1) (3)

In legumes, seed is non-endospermic. I, II, III, IV III, IV, VI

(2) I, II, V, (4) IV, V, I

202

BIOLOGY

EXERCISE - 2 | Window to Competitive Exams 1. 2. 3. 4. 5.

6.

7. 8.

9. 10. 11.

12. 13. 14.

Buttress roots are found in [CBSE'95] (1) Sorghum (2) banyan (3) Terminalia (4) Pandanus Which one of the following is a true fruit? [CBSE'96] (1) Apple (2) Pear (3) Cashew nut (4) Coconut Which part of the coconut produces coir? [CBSE'96] (1) Seed coat (2) Mesocarp (3) Epicarp (4) Pericarp Haustorial roots are present in [BHU'97] (1) Cactus (2) Acalypha (3) Zea mays (4) Cuscuta Which plant will lose its economic value if its fruits are produced by induced parthenocarpy? [CBSE'97] (1) Grape (2) Pomegranate (3) Banana (4) Orange Heterospory and seed habit are related to a structure called [CBSE'97] (1) spathe (2) bract (3) petiole (4) ligule The embryo in sunflower has [CBSE'98] (1) one cotyledon (2) two cotyledons (3) many cotyledons (4) no cotyledon Which one of the following is correct ? [AMU'98] (1) Malvaceae-Cotton (2) Leguminosae-Mango or Sunflower (3) Cucurbitaceae-Orange (4) Brassicaceae-Wheat The plant bearing clinging roots, is [CBSE'99] (1) Trapa (2) orchid (3) screw pine (4) Podostemon Most reduced form of stem is found in [AIIMS'2000] (1) bulb (2) rhizome (3) tuber (4) corm Reserve food is mainly found in [AIIMS'2000] (1) underground stems (2) underground modified tap roots (3) underground modified adventitious roots (4) all of the above In Opuntia, spines are modification of [AIIMS'2000] (1) stem (2) root (3) leaf (4) flower The edible part of cauliflower is [AIIMS'2000] (1) inflorescence (2) leaf (3) flower (4) stem If both the anthers and filaments are fused together to form a compact structure with sigmoid appearance the condition is termed as [AMU'2000] (1) syngenesious (2) androecious (3) syngynandrous (4) synandrous

15.

16.

17.

18.

19.

20.

21.

22.

23. 24.

25.

There are certain plant species which flower only once in their life span [AMU'2000] (1) polygamous (2) polycarpic (3) monocarpic (4) pericarpic An angiospermic plant produces unisexual and bisexual flowers on the same plant, the condition termed as (1) dioecious [AMU'2000] (2) trioecious (3) polygamous (4) andro-gynoecious Removal of seed coat in dormant seeds, by mechanical method is called [AFMC'2000] (1) separation (2) vernalization (3) emasculation (4) scarification If a fruit is developed from bicarpellary, bilocular with one ovule in each locule and pendulously attached and the wall of the ovary possess vittae, the fruit is designated as [AMU'2000] (1) caryopsis (2) cypsela (3) cremocarp (4) capsule Roots of which plant contains an oxidising agent? [CBSE'01] (1) Carrot (2) Soyabean (3) Mustard (4) Radish Fibrous root system is better adopted than tap root system for [BHU'01] (1) transport of organic matter (2) absorption of water and minerals (3) storage of food (4) anchorage of plant to soil Tetradynamous stamens are found in family [CBSE'95, 01] (1) malvaceae (2) solanaceae (3) cruciferae (4) liliaceae Bicarpellary gynoecium and oblique ovary occur in [CBSE'01] (1) mustard (2) banana (3) Pisum (4) brinjal Clove is [AIIMS'01] (1) flower bud (2) axillary bud (3) thalamus (4) ovule Edible part of banana is [CBSE'01] (1) epicarp (2) mesocarp and less developed endocarp (3) endocarp and less developed mesocarp (4) epicarp and mesocarp Which one is correct pair? [CBSE'01] (1) Tomato - Thalamus (2) Maize - Cotyledons (3) Guava - mesocarp (4) Date palm - Mesocarp

MORPHOLOGY OF FLOWERING PLANTS 26.

27.

28. 29.

30. 31. 32.

33.

34. 35.

36. 37. 38. 39.

In which of the following plants, leaf apex changes into tendril ? [AFMC'02] (1) Gloriosa (2) Smilax (3) Pisum sativum (4) Australian Acacia Match the following and choose the correct option List I List II [AFMC'02] I. Acicular (A) Grass II. Linear (B) Nerium N III. Lanceolate (C) Banana IV. Oblong (D) Pine (1) I-D, II-A, III-B, IV-C (2) I-D, II-A, III-C, IV-B (3) I-D, II-B, III-C, IV-A (4) I-D, II-C, III-B,IV-A A bract can be differentiated from bracteole by its (1) size (2) position [AMU'02] (3) function (4) colour If the anther is attached to the filament along the whole length, such condition is [BHU'02] (1) adnate (2) dorsifixed (3) basifixed (4) versatile In an exalbuminous seed, the food is stored within (1) endosperms (2) cotyledons [AMU'02] (3) seed coat (4) pericarp Haploid endosperm is found in [AMU'02] (1) wheat (2) gram (3) gymnosperm (4) algae Family leguminosae is divided on the basis of [AMU'02] (1) gynoecium (2) corolla (3) aestivation of calyx and corolla (4) corolla and androecium Pneumatophores are helpful in [AMU'03] (1) protein synthesis (2) respiration (3) carbohydrate metabolism (4) transpiration The modified stem of Opuntia is [BHU '03] (1) phyllode (2) phylloclade (3) cladode (4) staminode Branches of stem are [AMU'03] (1) exogenous in origin (2) endogenous in origin (3) partly exogenous and partly endogenous (4) superficial Spine, thorn and prickle are [BHU'03] (1) homologous (2) synonymous (3) analogous (4) protecting structures Which of the following can produce flowers and leaves? (1) Thorn (2) Spine [BHU'03] (3) Prickle (4) Phyllode Leaves arise from which part of plant? [AFMC'03] (1) Rhizome (2) Stem (3) Internode (4) Node In a tripinnate compound leaf, the leaf-lets develop on [BHU'03] (1) primary rachis (2) secondary rachis (3) tertiary rachis (4) petiole

203 40.

41. 42. 43.

44.

45. 46. 47.

48. 49. 50.

51.

52.

53.

Stipules are found in [AMU'03] (1) all dicots (2) all dicots and some monocots (3) some dicots and monocots (4) all dicots and monocots Capitulum inflorescence is a modification of (1) raceme (2) panicle [AMU'03] (3) spike (4) cyme Cyathium inflorescence is a modification of (1) racemose (2) cymose [AMU'03] (3) spike (4) capitulum Juicy hair–like structures observed in the lemon fruit develop from [CBSE'03] (1) mesocarp and endocarp (2) exocarp (3) mesocarp (4) endocarp The root differs from stem in having [AMU'04] (1) nodes and internodes (2) axillary buds (3) multicellular hairs (4) unicellular hairs A root-cap is usually absent in the roots of [AMU'04] (1) hydrophytes (2) epiphytes (3) parasites (4) all of the above An example of nodular root is [BHU'04] (1) Opuntia (2) leguminous plants (3) sugarcane (4) mango In Cuscuta the nodes give rise to special roots which penetrate the host tissue upto [BHU'04] (1) cortex (2) phloem (3) epidermis (4) pericycle New banana plants develop from [BHU'04] (1) rhizome (2) sucker (3) stolon (4) seed An offset is present in plants which are [BHU'04] (1) terrestrial (2) amphibious (3) aquatic (4) all of the above A number of leaflets arranged alternately or in opposite manner is known as [BHU'04] (1) simple leaf (2) pinnately compound leaf (3) palmately compound leaf (4) none of the above Inflorescence having verticels of small flowers borne in condensed dichasial cyme is characteristic of [AMU'04] (1) Ocimum (2) Hibiscus (3) Helianthus (3) Brassica An incomplete flower is [AMU'04] (1) always unisexual (2) always bisexual (3) either unisexual or bisexual (4) imperfect A flower having all the sepals and petals of the same size is [AMU'04] (1) actinomorphic (2) zygomorphic (3) asymmetric (4) either actinomorphic or zygomorphic

204 54. 55. 56. 57. 58. 59.

60.

61. 62.

63. 64.

65. 66.

67.

68.

69.

BIOLOGY Glumes are modified [AMU'04] (1) androecium (2) gynoecium (3) petals (4) bracts Mango juice is extracted from [CBSE'89, 02, 04] (1) epicarp (2) mesocarp (3) endocarp (4) pericarp and thalamus Fleshy fruits are [AMU'04] (1) indehiscent (2) dehiscent (3) schizocarpic (4) All of these The anthers in solanaceae are [AMU'04] (1) monothecus, introse (2) dithecus, extrose (3) dithecus, introse (4) monothecus, extrose Tuberous roots are found in [AMU'05] (1) Beta vulgaris (2) Daucus carota (3) Ipomoea batatas (4) Raphanus sativus In a twiner normally the climbing organ is a [BHU'05] (1) wire like stem (2) spring like tendril (3) woody curved hook (4) strong pointed spine When gynoecium is present in the top most position of thalamus, the flower is known as [AMU'05] (1) inferior (2) epigynous (3) perigynous (4) hypogynous Maize grain is [AFMC'05] (1) seed (2) embryo (3) ovule (4) fruit The primary function of underground modified stem is (1) perennation [BHU'06] (2) storage (3) vegetative propagation (4) reproduction In Nepenthes, the pitcher is a modification of [BHU'06] (1) whole leaf (2) petiole (3) leaf-base (4) lamina Main function of leaf is [BHU'06] (1) exchange of gases (2) increase the beauty of a tree (3) manufacturing of food (4) nerve impulse induction Basically a verticillaster inflorescence is a type of (1) cymose (2) racemose [AMU'06] (3) raceme (4) panicle What type of placentation is seen in sweet pea? [CBSE'06] (1) Axile (2) Free central (3) Marginal (4) Basal Long filamentous threads protruding at the end of the young cob of maize are [CBSE'2000, 06] (1) styles (2) ovaries (3) hairs (4) anthers In hypogynous flowers the ovary occurs at [AMU'06] (1) the highest position (2) the lower position (3) intermediate position (4) lateral position Aril represents the edible part of [CBSE'97, 99, 05, 06] (1) banana (2) litchi (3) mango (4) apple

70.

71.

72.

73. 74. 75.

76. 77.

78. 79.

80. 81. 82. 83.

Pineapple (ananas) fruit develops from [CBSE'06] (1) a multipistillate syncarpous flower (2) a cluster of compactly borne flowers on a common axis (3) a multilocular monocarpellary flower (4) a unilocular polycarpellary flower A simple fruit develops from [AMU'06] (1) multicarpellary syncarpous pistil (2) mono-or multicarpellary syncarpous pistil (3) multicarpellary apocarpous pistil (4) multicarpellary apo-& syncarpous pistil Pentamerous, actinomorphic flowers, bicarpellate ovary with oblique septa and fruit a capsule of berry, are characteristic features of [CBSE'06] (1) brassicaceae (2) solanaceae (3) liliaceae (4) asteraceae Root hairs are ontogenetically [AMU'07] (1) exogenous (2) endogenous (3) Both (1) and (2) (4) none of these Sucker is a subaerial stem modification seen in [BHU'07] (1) Hydrocotyle (2) Chrysanthemum (3) Pistia (4) Launea In a raceme the flowers are [AMU'07] (1) arranged in a basipetal succession (2) arranged in acropetal succession (3) bisexual (4) monosexual Geocarpic fruits are produced by [AFMC'07] (1) carrot (2) onion (3) ground nut (4) watermelon Apomixis is [AIIMS'07] (1) formation of seeds by fusion of gametes . (2) formation of seeds without syngamy and meiosis. (3) formation of seeds with syngamy but no meiosis. (4) none of the above. Replum is present in the ovary of flower of [CBSE'08] (1) lemon (2) mustard (3) sunflower (4) pea Which is the mo-st active part of root used in water absorption ? [AMU'09] (1) Root cap (2) Maturation zone (3) Meristematic zone (4) Zone of elongation An example of axile placentation is [CBSE'09] (1) Dianthus (2) lemon (3) marigold (4) mustard A perianth bearing flower is [AMU'09] (1) monochlamydous (2) dichlamydous (3) achlamydous (4) metachlamydous Epipetalous stamens are found in [AMU'09] (1) cruiferae (2) solanaceae (3) liliaceae (4) mimosaceae Aggregate fruit develops from [AIIMS'09] (1) syncarpous ovary (2) multicarpellary, syncarpous ovary (3) unilocular ovary (4) multicarpellary, apocarpous ovary

MORPHOLOGY OF FLOWERING PLANTS 84. 85.

86.

87.

88.

89.

90.

91.

Wheat grain is a type of a [AFMC'09] (1) berry (2) nut (3) caryopsis (4) legume (pod) The floral formula [CBSE PMT 2009]

is that of: (1) Soyabean (2) Sunhemp (3) Tobacco (4) Tulip An example of axile placentation is: [CBSE PMT 2009] (1) Dianthus (2) Lemon (3) Marigold (4) Argemone The characteristic type of placentation found in the members of caryophyllaceae is [Kerala PMT 2009] (1) parietal (2) marginal (3) basal (4) free central Which of the following statements are correct? [Kerala PMT 2009] (i) when a fruit develops from the inflorescence, it is composite (ii) mesocarp is the edible part in apple (iii) gynobasic style is seen in Ocimum (iv) hypanthodium is a special type of inflorescence found in Euphorbia species (1) (i) and (iv) are correct (2) (i) and (iii) are correct (3) (i) and (ii) are correct (4) (ii), (iii) and (iv) are correct Which one of the following represents the floral characters of poaceae? [Kerala PMT 2009] (1) pedicellate, bracteate, bisexual, tetramerous, actinomorphic, complete and superior ovary (2) pedicellate, bracteate, bisexual, pentamerous, zygomorphic, complete and superior ovary (3) sessile, bracteate, bracteolate, incomplete, uni- or bisexual, perianth modified into lodicules, stamens three, syncarpous, superior ovary and feathery stigma (4) bracteate, unisexual actinomorphic, stamens five and inferior ovary Select the characters which are not applicable to the family solanaceae? [Kerala PMT 2009] (i) epipetalous and syngenesious anthers (ii) bicarpellary and syncarpous ovary (iii) oblique ovary with axile placentation (iv) stamens six, arranged in two whorls (v) bicarpellary, syncarpous and inferior ovary (1) (ii) and (iii) only (2) (i), (iv) and (v) only (3) (ii), (iv) and (v) only (4) (i) and (iii) only Match column I with II and choose the right option [Kerala PMT 2009] I II 1. Artemisia A. Fibre 2. Astragalus B. Insecticide 3. Phormium C. Rat poison 4. Chrysanthemum D. Medicine 5. Withania E. Vermifuge F. Gum

205

92.

93.

94.

95. 96. 97. 98. 99.

100. 101.

102.

103.

104.

(1) 1 - D, 2 - C, 3 - F, 4 - B, 5 - E (2) 1 - B, 2 - E, 3 - D, 4 - C, 5 - A (3) 1 - C, 2 - E, 3 - A, 4 - F, 5 - D (4) 1 - E, 2 - F, 3 - A, 4 - B, 5 - D Which one of the following is an example of subaerial modification of stem? [Kerala PMT 2009] (1) Agave (2) Oxalis (3) Asparagus (4) Tridax (e) Polyalthia Multicostate parallel type of venation is found in the leaves of [Kerala PMT 2009] (1) grasses and palms (2) banana and Canna (3) castor and china rose (4) mango and peepal

The above inflorescence is a [Kerala PMT 2009] (1) cyatnium (2) dichasial cyme (3) umbel (4) panicle The leaves are modified into spines in [Kerala PMT 2009] (1) Nepenthes (2) Opuntia (3) Australian Acacia (4) Utricularia In unilocular ovary with a single ovule the placentation is (1) Marginal (2) Basal [CBSE'10] (3) Free Central (4) Axile Keel is characteristic of the flowers of [CBSE'10] (1) gulmohur (2) Cassia (3) Calotropis (4) bean Ovary is half-inferior in the flowers of [CBSE'10] (1) guava (2) plum (3) brinjal (4) cucumber The technical term used for the androecium in a flower of China rose ((Hibiscus rosa sinensis) is [CBSE'10] (1) monoadelphous (2) diadelphous (3) polyandrous (4) polyadelphous Which of the following is a false fruit ? [AFMC'10] (1) Apple (2) Coconut (3) Plum (4) Mango A fruit, developing from an inflorescence is called [AFMC'10] (1) etaerio (2) composite fruit (3) achene (4) berry In unilocular ovary with a single ovule the placentation is: [CBSE PMT 2010] (1) Marginal (2) Basal (3) Free Central (4) Axile Keel is characteristic of the flowers of:[CBSE PMT 2010] (1) Gulmohur (2) Cassia (3) Calotropis (4) Bean Ovary is half-inferior in the flowers of:[CBSE PMT 2010] (1) guava (2) plum (3) brinjal (4) cucumber

206

BIOLOGY

105. The technical term used for the androecium in a flower of China rose ((Hibiscus rosa sinensis) is:[CBSE PMT 2010] (1) Monadelphous (2) Diadelphous (3) Polyandrous (4) Polyadelphous 106. Which of the following is wrongly matched? [Kerala PMT 2010] (1) Indigofera dye (2) Sesbania fodder (3) Petunia fumigatory (4) Aloe medicine 107. Which one of the following floral formulae represents the mustard plant? [Kerala PMT 2010] (1)

K2+2 C4A2+4 G(2)

(2)

P3+3 C4A3+3 G(3)

(3)

K(5)C(5)A(5) G(2)

(4)

K2+2 C4 A2+4 G(2)

108. The monocotyledonous seed consists of one large and shield shaped cotyledon known as [Kerala PMT 2010] (1) aleurone layer (2) scutellum (3) coleoptile (4) hilum 109. Flowers are zygomorphic in [CBSE'11] (1) mustard (2) gulmohur (3) cotton (4) Datura 110. If a fruit is developed from bicarpellary, syncarpous, superior ovary with parietal placentation and unilocular when young but becoming bilocular with age and also pod-like in appearance is termed as [AFMC'11] (1) lomentum (2) silicula (3) siliqua (3) cypsela 111. Which of following type of anther is found in malvaceae? [AIIMS'11] (1) Monothecous (2) Dithecous (3) Polythecous (4) Without thecous 112. Which one of the following statements is correct ? [CBSE PMT 2011] (1) In tomato, fruit is a capsule (2) Seeds of orchids have oil-rich endosperm (3) Placentation in primose is basal (4) Flower of tulip is a modified shoot 113. What would be the number of chromosomes of the aleurone cells of a plant with 42 chromosomes in its root tip cells? [CBSE PMT 2011] (1) 42 (2) 63 (3) 84 (4) 21 114. The correct floral formula of chilli is :[CBSE PMT 2011] (1)

(2)

(3)

(4)

115. Flowers are zygomorphic in : [CBSE PMT 2011] (1) mustard (2) gulmohur (3) ioruato (4) Datura

116. The ovary is half inferior in flowers of[CBSE PMT 2011] (1) peach (2) cucumber (3) cotton (4) guava 117. Which one of the following diagrams represents the placentation in Dianthus? [CBSE PMT 2011M] (1)

(2)

(3)

(4)

118. Whorled, simple leaves with reticulate venation are present in [CBSE PMT 2011M] (1) Calotropis (2) Neem (3) China rose (4) Alstonia 119. Sweet potato is homologous to [CBSE PMT 2011M] (1) Potato (2) Colocasia (3) Ginger (4) Turnip 120. If a fruit is developed from bicarpellary, syncarpous, superior ovary with parietal placentation and unilocular when young but becoming bilocular with age and also pod-like in appearance is termed as [AFMC 2011] (1) lomentum (2) silicula (3) siliqua (4) cypsela 121. Typical floral formula of Ranunculaceae is [AFMC 2011] 

(1) ⊕ OK C A ∝ G−∝ + 5 5 

C A ∝ G− 1 (2) ⊕ OK + (5) (6) 9+1 

C A G (3) ⊕ OK + (5) (6) (∝) − 

122. 123. 124. 125. 126. 127.

(5 −8)

(4) ⊕ OK 2+ 2 C4 A 4+ 2 G− (2) + Catkin inflorescence is found in [JIPMER-2011] (1) wheat (2) oat (3) mulberry (4) fig Epigynous flowers are present in [JIPMER-2011] (1) mustard (2) brinjal (3) china rose (4) cucumber In Dianthus, placentation is [JIPMER-2011] (1) basal (2) free central (3) axile (4) marginal The term ‘keel’ is used for special type of [JIPMER-2011] (1) sepals (2) petals (3) stamens (4) carpels Coffee and Quinine are obtained from the [JIPMER-2011] (1) Leguminosae (2) Asteraceae (3) Rubiaceae (4) Poaceae Study the following statements and select the correct option [Kerala PMT 2011] (1) Buds are present in axil of leaflets of the compound leaf. (2) Pulvinus leaf-base is present in some leguminous plants. (3) In Alstonia, the petioles expand, become green and synethesize food. (4) Opposite phyllotaxy is seen in guava.

MORPHOLOGY OF FLOWERING PLANTS (1) (2) and (4) are correct but (1) and (3) are wrong. (2) (1) and (3) are correct but (2) and (4) are wrong. (3) (1) and (4) are correct but (2) and (3) are wrong. (4) (2), (3) and (4) are correct but (1) is wrong. 128. Select the correct match. [Kerala PMT 2011] (1) Colchicum autumnale Solanaceae (2) Petunia Solanaceae (3) Gloriosa Fabaceae (4) Trifolium Liliaceae 129. Match the following and choose the correct combination from the options given below. [Kerala PMT 2011] Column I (Placentation Types) A Basal B Free central C Parietal D Axile E Marginal

130.

131.

132.

133.

1 2 3 4 5

Column II (Represented in) Dianthus Pea Lemon Marigold Argemone

(1) A – 1, B – 2, C – 3, D – 4, E – 5 (2) A – 2, B – 3, C – 4, D – 5, E – 1 (3) A – 4, B – 1, C – 5, D – 3, E – 2 (4) A – 4, B – 3, C – 5, D – 1, E – 2 The plant having monadelphous stamens and axile placentation is [Kerala PMT 2011] (1) lemon (2) pea (3) tomato (4) china rose Which of the following plants have long slender and coiled stem tendrils developed from axillary buds? [Kerala PMT 2011] (1) grapevine and pumpkins (2) Australian Acacia and watermelon (3) Bougainvillea and cucumber (4) Strawberry and grapevine Select the correct statements. [Kerala PMT 2011] (1) From the region of elongation, some of the epidermal cells form root hairs (2) Pneumatophores are seen in Rhizophora. (3) Adventitious roots are seen in the banyan tree. (4) Maize and sugarcane have prop roots. (1) A & D (2) A, C & D (3) C & D (4) B & C Match the following and select the correct combination from the options given below. [Kerala PMT 2011] Column I (Stem Modifications) A Underground stem B Stem tendril C Stem thorns D Flattened stem E Fleshy cylindrical stem (1) (2) (3) (4)

1 2 3 4 5

Column II (Found in) Euphorbia Opuntia Potato Citrus Cucumber

A – 1, B – 2, C – 3, D – 5, E – 4 A – 2, B – 3, C – 4, D – 5, E – 1 A – 3, B – 4, C – 5, D – 1, E – 2 A – 3, B – 5, C – 4, D – 2, E – 1

207 134. The following diagrams represent the types of aestivation in corolla. Identify the correct combination of labelling. [Kerala PMT 2011]

(1) A – Valvate, B – Twisted, C – Vexillary, D – Imbricate (2) A – Valvate, B – Vexillary, C – Twisted, D – Imbricate (3) A – Vexillary, B – Imbricate, C – Twisted, D – Valvate (4) A – Valvate, B – Twisted, C – Imbricate, D – Vexillary 135. Which of the following plants has the floral characters like zygomorphic flower, vexillary aestivation, diadelphous androecium and marginal placentation? [Kerala PMT 2011] (1) Pisum (2) Belladonna (3) Brinjal (4) Asparagus 136. From the options given below, find out the correct floral formula for a flower having the following characters namely actinomorphic, bisexual, five united sepals, five united petals, stamens five and epipetalous, bicarpellary, syncarpous with superior ovary. [Kerala PMT 2011] (1)

K(5)C(5)A(5) G(2) (2)

K(5)C(5)A(5) G(2)

(3)

K(5)C(5)A(5) G(2) (4)

K(5)C(5)A(5) G(2)

137. Placentation in tomato and lemon is [CBSE'2012] (1) Parietal (2) Free central (3) Marginal (4) Axile 138. Cymose inflorescence is present in : [CBSE'2012] (1) Solanum (2) Sesbania (3) Trifolium (4) Brassica 139. Phyllode is present in : [CBSE'2012] (1) Asparagus (2) Euphorbia (3) Australian Acacia (4) Opuntia 140. The gynoecium consists of many free pistils in flowers of (1) Aloe (2) Tomato [CBSE'2012] (3) Papaver (4) Michelia 141. How many plants in the list given below have composite fruits that develop from an inflorescence? Walnut, poppy, radish, fig, pineapple, apple, tomato, mulberry (1) Four (2) Five [CBSE'2012] (3) Two (4) Three 142. The coconut water and the edible part of coconut are equivalent to : [CBSE'2012] (1) Endosperm (2) Endocarp (3) Mesocarp (4) Embryo 143. Vexillary aestivation is characteristic of the family (1) Fabaceae (2) Asteraceae [CBSE'2012] (3) Solanaceae (4) Brassicaceae

208 144. Which one of the following organisms is correctly matched with its three characteristics? [CBSE'2012M] (1) Pea: C3 pathway, Endospermic seed, Vexillary aestivation (2) Tomato: Twisted aestivation, Axile placentation, Berry (3) Onion: Bulb, Imbricate aestivation, Axile placentation (4) Maize: C3 pathway, Closed vascular bundles, Scutellum 145. How many plants in the list given below have marginal placentation? Mustard, Gram, Tulip, Asparagus, Arhar, Sun hemp, Chilli, Colchicine, Onion, Moong, Pea, Tobacco, Lupin (1) Four (2) Five [CBSE'2012M] (3) Six (4) Three 146. Placentation in tomato and lemon is [CBSE PMT 2012] (1) Parietal (2) Free central (3) Marginal (4) Axile 147. Cymose inflorescence is present in : [CBSE PMT 2012] (1) Solanum (2) Sesbania (3) Trifolium (4) Brassica 148. Phyllode is present in : [CBSE PMT 2012] (1) Asparagus (2) Euphorbia (3) Australian Acacia (4) Opuntia 149. The gynoecium consists of many free pistils in flowers of [CBSE PMT 2012] (1) Aloe (2) Tomato (3) Papaver (4) Michelia 150. How many plants in the list given below have composite fruits that develop from an inflorescence Walnut, poppy, radish, fig, pineapple, apple, tomato, mulberry [CBSE PMT 2012] (1) Four (2) Five (3) Two (4) Three 151. The coconut water and the edible part of coconut are equivalent to : [CBSE PMT 2012] (1) Endosperm (2) Endocarp (3) Mesocarp (4) Embryo 152. Vexillary aestivation is characteristic of the family [CBSE PMT 2012] (1) Fabaceae (2) Asteraceae (3) Solanaceae (4) Brassicaceae 153. Which one of the following organisms is correctly matched with its three characteristics? [CBSE PMT 2012M] (1) Pea: C 3 pathway, Endospermic seed, Vexillary aestivation (2) Tomato: Twisted aestivation, Axile placentation, Berry (3) Onion: Bulb, Imbricate aestivation, Axile placentation (4) Maize: C 3 pathway, Closed vascular bundles, Scutellum

BIOLOGY 154. How many plants in the list given below have marginal placentation? Mustard, Gram, Tulip, Asparagus, Arhar, Sun hemp, Chilli, Colchicine, Onion, Moong, Pea, Tobacco, Lupin [CBSE PMT 2012M] (1) Four (2) Five (3) Six (4) Three 155. Prickles of rose are [AIIMS 2012] (1) Modified leaves (2) Modified stipules (3) Exogenous in origin (4) Endogenous in origin 156. Aril is the edible part of [AFMC 2012] (1) apple (2) litchi (3) banana (4) mango. 157. Wheat is which of the following types of fruit? [AFMC 2012] (1) Berry (2) Nut (3) Caryopsis (4) Legume (pod) 158. In Ruscus, the stem is a (1) phyllode (2) cladode (3) offset (4) sucker 159. Ginger is an underground stem. It is distinguished from root because [JIPMER-2012] (1) it lacks chlorophyll (2) it stores food (3) it has nodes and internodes (4) it has xylem and vessels 160. Choose the specific characters of the flowers of Canna. [Kerala PMT 2012] (1) Actinomorphic and radial symmetry (2) Irregular and bilateral symmetry (3) Irregular and zygomorphic (4) Irregular and asymmetric 161. The distinct features of fabaceae are [Kerala PMT 2012] (1) zygomorphic, diadelphous and monocarpellary (2) actinomorphic, monadelphous and monocarpellary (3) zygomorphic, monadelphous and pentacarpellary (4) zygomorphic, polyadelphous and tricarpellary (e) zygomorphic, diadelphous and bicarpellary 162. Find out the pairs, which are correctly matched with respect to aestivation of petals. [Kerala PMT 2012] I. Valvate Calotropis II. Twisted Bean III. Imbricate Cassia IV. Vexillary China rose (1) II and IV (2) I and II (3) I and III (4) III and IV 163. Find out the correctly matched pair. [Kerala PMT 2012] Placentation types Represented in (1) Marginal Tomato (2) Axile Pea (3) Parietal Primrose (4) Basal Marigold

MORPHOLOGY OF FLOWERING PLANTS 164. Match the following and choose the correct combination from the options given. [Kerala PMT 2012] Column I Column II (Family) (Androecium formula) A. Brassicaceae 1. A3+3 B. Fabaceae 2. A(5) C. Solanaceae 3. A(9) + 1 D. Liliaceae 4. A2 + 4 (1) A – 4; B – 3; C – 2, D – 1 (2) A – 1; B – 2; C – 3, D – 4 (3) A – 2; B – 3; C – 4, D – 1 (4) A – 3; B – 4; C – 1, D – 2 165. In China rose the flowers are : [AIPMT 2013] (1) Actinomorphic, epigynous with valvate aestivation (2) Z y g o m o r p h i c , h y p o g y n o u s w i t h i m b r i c a t e aestivation (3) Zygomorphic, epigynous with twisted aestivation (4) Actinomorphic, hypogynous with twisted aestivation 166. Among bitter gourd, mustard, brinjal, pumpkin, china rose, lupin, cucumber, sunhemp, gram, guava, bean, chilli, plum, petunia, tomato, rose, withania, potato, onion, aloe and tulip how many plants have hypogynous flower?[AIPMT 2013] (1) Ten (2) Fifteen (3) Eighteen (4) Six 167. Among flowers of Calotropis, tulip, Sesbania, Asparagus, Colchicine, Sweet pea, Petunia, Indigofera, Mustard, Soyabean, Tobacco and groundnut how many plants have corolla with valvate aestivation? [NEET Kar. 2013] (1) Five (2) Six (3) Seven (4) Eight 168. How many plants among China rose, Ocimum, sunflower, mustard, Alstonia, guava, Calotropis and Nerium (Oleander) have opposite phyllotaxy? [NEET Kar. 2013] (1) Two (2) Three (3) Four (4) Five 169. In a cymose inflorescence the main axis (1) Terminates in a flower [NEET Kar. 2013] (2) Has unlimited growth (3) Bears a solitary flower (4) Has unlimited growth but lateral branches end in flowers 170. Inflorescence is racemose in [NEET Kar. 2013] (1) Soyabean (2) Brinjal (3) Tulip (4) Aloe 171. Which of the following are not characteristic features of fabaceae? [AIIMS 2013] (1) Tap root system, compound leaves and raceme inflorescence. (2) Flowers actinomorphic, twisted aestivation and gamopetalous. (3) Stamens 10, introrse, basifixed, dithecous. (4) Monocarpellary, ovary superior and bent stigma. 172. Consider the following statements regarding the root system of angiosperms. [Kerala PMT 2013] I. In monocots, the fibrous root system arises from the base of the stem.

209

173.

174.

175.

176.

177.

II. The region of elongation is called the root hair region. III. In sweet potato, the adventitious roots get swollen and store food. IV. The stems of maize and sugarcane have supporting roots called prop roots. (1) I and II are correct but III and IV are wrong. (2) II and III are correct but I and IV are wrong. (3) II and IV are correct but I and III are wrong. (4) I and III are correct but II and IV are wrong. I. Pulvinus leaf base is present in some leguminous plants. II. Whorled phyllotaxy is seen in Calotropis. III. In Australian acacia, the petioles expand, become green and synthesise food. IV. A bud is present in the axil of leaflets of the compound leaf. Of the above statement [Kerala PMT 2013] (1) I and IV are correct but II and III are wrong. (2) II and III are correct but I and IV are wrong. (3) I and III are correct but II and IV are wrong. (4) III and IV are correct but I and II are wrong. When one is a fodder plant, the other is a medicinal plant. They are [Kerala PMT 2013] (1) Sesbania and belladonna (2) Trifolium and Petunia (3) Lupin and Colchicum (4) Aloe and Trifolium Stem tendrils are seen in [Kerala PMT 2013] (1) Citrus and Bougainvillea (2) Citrus and Watermelon (3) Cucumber and Pumpkins (4) Opuntia and Bougainvillea Match the following and choose the correct combination from the options given. [Kerala PMT 2013] Column I Column II (Position of floral parts) (Represented in) on thalamus) (1) Hypogynous (1) Ray florets of sunflower (2) Perigynous (2) Brinjal (3) Epigynous (3) Peach (1) A-2, B-1, C-3 (2) A-1, B-2, C-3 (3) A-3, B-2, C-1 (4) A-2, B-3, C-1 Which one of the following is correct explanation for the floral formulas [Kerala PMT 2013] %O K(5) C1+2+(2) A(9)+1 GI? + (1) Zygomorphic, bisexual, sepals five and gamosepalous, petals five and papilionaceous, anthers ten and monadelphous ovary superior and monocarpellary. (2) Zygomorphic, unisexual, sepals five and gamosepalous, petals five and polypetalous, anthers nine united and one free, ovary superior and monocarpellary.

210

178.

179. 180.

181.

182. 183.

184.

185.

BIOLOGY (3) Zygomorphic, bisexual, sepals five and gamosepalous, petals five and papilionaceous, anthers ten and diadelphous, ovary superior and monocarpellary. (4) Zygomorphic, bisexual, sepals five and united, petals five and united, anthers ten and diadelphous, ovary superior and monocarpellary. Which of the following is the characteristic feature of androecium of Pisum sativum? [Kerala PMT 2013] (1) Ten stamens, diadelphous and dithecous anther. (2) Five stamens, diadelphous and monothecous anther. (3) Five stamens, epipetalous and dithecous anther. (4) Six stamens, epipetalous and dithecous anther. Placenta and pericarp are both edible portions in: (1) Apple (2) Banana [AIPMT - 2014] (3) Tomato (4) Potato When the margins of sepals or petals overlap one another without any particular direction, the condition is termed as: [AIPMT - 2014] (1) Vexillary (2) Imbricate (3) Twisted (4) Valvate Which one of the following statements is correct? [AIPMT - 2014] (1) The seed in grasses is not endospermic. (2) Mango is a parthenocarpic fruit. (3) A proteinaceous aleurone layer is present in maize grain. (4) A sterile pistil is called a staminode. An example of edible underground stem is: (1) Carrot (2) Groundnut [AIPMT - 2014] (3) Sweet potato (4) Potato An aggregate fruit is one which develops from: [AIPMT - 2014] (1) Multicarpellary syncarpous gynoecium (2) Multicarpellary apocarpus gynoecium (3) Complete inflorescence (4) Multicarpellary superior ovary Placenta and pericarp are both edible portions in: [AIPMT 2014] (1) Apple (2) Banana (3) Tomato (4) Potato When the margins of sepals or petals overlap one another without any particular direction, the condition is termed as: [AIPMT 2014] (1) Vexillary (2) Imbricate (3) Twisted (4) Valvate

186. Which one of the following statements is correct? [AIPMT 2014] (1) The seed in grasses is not endospermic. (2) Mango is a parthenocarpic fruit. (3) A proteinaceous aleurone layer is present in maize grain. (4) A sterile pistil is called a staminode. 187. An example of edible underground stem is:[AIPMT 2014] (1) Carrot (2) Groundnut (3) Sweet potato (4) Potato 188. An aggregate fruit is one which develops from: [AIPMT 2014] (1) Multicarpellary syncarpous gynoecium (2) Multicarpellary apocarpus gynoecium (3) Complete inflorescence (4) Multicarpellary superior ovary 189. Leaves become modified into spines in :- [AIPMT 2015] (1) Pea (2) Onion (3) Silk Cotton (4) Opuntia

K C A G 190. ⊕ O + (5) (5) 5 (2) is the floral formula of [AIPMT 2015] (1) Sesbania (2) Petunia (3) Brassica (4) Allium 191. Keel is the characteristic feature of flower of : [AIPMT 2015] (1) Indigofera (2) Aloe (3) Tomato (4) Tulip 192. Perigynous flowers are found in :[AIPMT 2015] (1) Cucumber (2) China rose (3) Rose (4) Guava 193. In ginger vegetative propagation occurs through: [AIPMT 2015] (1) Offsets (2) Bulbils (3) Runners (4) Rhizome 194. Flowers are unisexual in: [Re-Test AIPMT 2015] (1) Cucumber (2) China rose (3) Onion (4) Pea 195. Which one of the following fruits is parthenocarpic? [Re-Test AIPMT 2015] (1) Apple (2) Jackfruit (3) Banana (4) Brinjal 196. Axile placentation is present in [Re-Test AIPMT 2015] (a) Lemon

(b) Pea

(c) Argemone

(d) Dianthus

MORPHOLOGY OF FLOWERING PLANTS

211

EXERCISE - 3 | Test Yourself 1.

2.

3.

Rearrange the following zones are seen in the root and choose the correct option (A) Root hair zone (B) Zone of meristems (C) Rootcap zone (D) Zone of maturation (E) Zone of elongation (1) C,B,E,A,D (2) A,B,C,D,E (3) D,E,A,C,B (4) E,D,C,B,A Roots develop from parts of the plant other than radicle are called (1) tap roots (2) fibrous roots (3) adventitious roots (4) nodular roots Matching the following and choose the correct option A. B. C. D. E.

4.

5.

6.

7. 8.

Column – I Column – II Tubercular storage I. Tinospora roots Pneumatophores II. Heritiera Haustoria III. Asparagus Prop-roots IV. Viscum Assimilatory roots V. Screwpine

(1) A–II, B–III, C–IV, D–V, E–I (2) A–III, B–IV, C–V, D–I, E–II (3) A–III, B–I, C–II, D–V, E–IV (4) A–III, B–II, C–IV, D–V, E–I Respiratory roots and viviparous reproduction are the characteristic of (1) hydrophytes (2) xerophytes (3) mesophytes (4) mangroves Which of the following groups of plants are propagated through underground root? (1) Bryophyllum & Kalanchoe (2) Ginger, potato, onion & zamikand (3) Pistia, Chrysanthemum & pineapple (4) Sweet potato, Asparagus, tapioca & Dahlia Lateral root branches arise from parent root by the formation of roots primordia by division of (1) pericycle cell opposite to protoxylem (2) endodermis cell opposite to protoxylem (3) cortical cells opposite to protoxylem (4) pericyle cells lying between two protoxylem Root hair arises from (1) pericycle (2) endodermis (3) cortex (4) epiblema A hydrophyte with swollen petiole and with a single vascular bundle in the root is (1) Jussiaea (2) Trapa (3) Ceratophyllum (4) Potamogeton

9.

10.

11.

12. 13.

14.

15.

16.

Parts of two plants were observed. Structure-A develops aerially and produces roots when comes in contact with the soil. Structure-B develops from underground part of the stem, grows obliquely, becomes aerial and produces roots on its lower surface. Identify A and B. (1) Sucker, stolon (2) Stolon, runner (3) Stolon, sucker (4) Runner, stolon Identify the correct order of the following four zones in the root from apex to base. I. Mineral absorption zone II. Meristematic zone III. Maturation zone IV. Water absorption zone (1) II, III, IV, I (2) IV, III, II, I (3) II, IV, I, III (4) I, II, IV, III Starch is accumulated in large quantities in potato tuber because (1) it is useful for storage. (2) tubers respire slowly. (3) starch is synthesized in tubers. (4) translocated sucrose is polymerized here. Which is not a stem modification (1) Rhizome of ginger (2) Corm of Colocasia (3) Pitcher of Nepenthes (4) Tuber of potato Ginger is a stem which can be differentiated from root because it (1) grows parallel to ground. (2) stores food. (3) lacks chlorophyll. (4) has nodes and internodes. In humid climate, presence of spines in shrubs is (1) to reduce transpiration. (2) to defend against mammal herbivory. (3) to defend against wood cutters. (4) to check seed predation by birds. Potato and sweet potato (1) have edible parts which are homologous organs. (2) have edible parts which are analogous organs. (3) have been introduced in India from the same place. (4) are two species of the same genus. Which of the following statements is/are true? I. If the stem is joined with solid nodes and hollow internodes, it is called caudex. II. In Tridax, the stem is decumbent. III. Corm is a condensed form of rhizome growing more or less in vertical direction. IV. Sucker is an underground modification of stem. V. Biparous type of cymose branching is seen in Saraca. (1) I, IV and V only (2) II and III only (3) II, III and V only (4) III and IV only

212 17.

18.

19.

20.

21.

22.

BIOLOGY Which one of the following statement is correct? 1. Bulb of Allium cepa is a modified stem. 2. Cloves of Allium sativum are fleshy scale leaves. 3. Corm of Colocasia is a modified root. 4. Tendril in Vitis vinifera is a modified axillary bud. Match the following columns Column I Column II. A. Opuntia I. Stem thorns B. Asparagus II. Phylloclades C. Citrus III. Cladodes A B C (1) I II III (2) II III I (3) III II I (4) II I III Venation is a term used to describe the pattern of arrangement of (1) floral organs (2) flower in infloresence (3) veins and veinlets in a lamina (4) all of them Phyllotaxis is (1) mode of leaf arrangement on stem (2) types of roots (3) arrangement of sepals and petals in a flower (4) type of ovary Isobilateral leaf is found in (1) dicots (2) monocots (3) hydrophytes (4) xerophytes Chosse the correct combinations List-I List-II (A) Entire leaf modified (i) Clematis into a spine (B) Leaf except stipules (ii) Citrus modified into a tendril (C) Stipules modified into (iii) Euphorbia a tendril (D) First leaf of axillary (iv) Lathyrus bud modified into a spine

23.

A B C D (1) (iii) (iv) (i) (ii) (2) (iii) (i) (iv) (ii) (3) (ii) (iii) (i) (iv) (4) (iv) (ii) (i) (iii) 1/3 spiral phyllotaxy (called Tristichous) means (1) 3 rows of alternate rows (2) In one circle, there are 3 leaves (3) The angular divergence between 2 leaves is 120° (4) All of these

24.

25.

26.

27.

28.

A unipinnate compound leaf can be differentiated from a branch having simple leaves by (1) presence of terminal bud in compound leaf (2) absence of veins in the leaflets (3) presence of buds in the axils of leaflets (4) presence of buds in the axils of leaves Which statement is true about the habitat of leaves? (1) Leaves of aquatic plants have large air spaces. (2) Leaves of shaddy plants are large and thin. (3) The leaves which are submerged in water have multiple layer of epidermis. (4) None of the above. The main difference between thorns and prickles is in having (1) endogenous origin (2) vascular supply (3) bark (4) all of these In an inflorescence where flowers are borne laterally in an acropetal succession, the position of the youngest floral bud shall be (1) proximal (2) distal (3) intercalary (4) any where Select the correct option A B C D E

29.

List I Spike Capitulum Dichasial cyme Multiparous cyme Verticillaster

I. II. III. IV. V.

List II Bougainvillea Coleus Adhatoda Zinnia Asclepias

(1) A – III, B – IV, C – I, D – V, E – II (2) A – III, B – I, C – IV, D – V, E – II (3) A – II, B – IV, C – I, D – V, E – III (4) A – IV, B – II, C – V, D – I, E – III Find out the correct sequence of labelling of diagram given below

(1) A – spike, B – raceme, C – dichasial cyme, D – monochasial cyme (2) A – raceme, B – spike, C – monochasial cyme, D – dichasial cyme (3) A – dichasial cyme, B – monochasial cyme, C – raceme, D – spike (4) A – spike, B – dichasial cyme, C – monochasial cyme, D – raceme (5) A – raceme, B – dichasial cyme, C – spike, D – monochasial cyme

MORPHOLOGY OF FLOWERING PLANTS 30.

31.

Which of the following statements are correct? (i) When a fruit develops from the inflorescence, it is composite. (ii) Mesocarp is the edible part in apple. (iii) Gynobasic style is seen in Ocimum. (iv) Hypanthodium is a special type of inflorescence found in Euphorbia species. (1) (i) and (iv) are correct (2) (i) and (iii) are correct (3) (i) and (ii) are correct (4) (ii), (iii) and (iv) are correct (5) (ii) and (iv) are correct Given inflorescence is a

213 40.

41.

42.

43.

32. 33.

34.

35. 36.

37.

38.

39.

(1) cyathium (2) dichasial cyme (3) umbel (4) verticillaster Opening of flowers in the cymose inflorescence is (1) acropetal (2) centrifugal (3) basipetal (4) centripetal Most prominent function inflorescence is of (1) dispersal of seeds. (2) formation of more fruit. (3) formation of pollen grains. (4) dispersal of pollens. In a plant, the peduncle is elogated and it bears pedicillate flowers. The older flowers lie towards the base and the younger ones near the apex. The inflorescence is (1) raceme (2) corymb (3) umbel (4) head Polyadelphous condition is related to (1) calyx (2) androecium (3) corolla (4) gynoecium The perianth is the term used when (1) androecium and gynoecium are similar (2) androecium and calyx are similar (3) corolla and gynoecium are similar (4) calyx and corolla are similar Maturation of male and female sex organs at different time in a flower is called (1) apogamy (2) polygamy (3) dichogamy (4) herkogamy A monocarpic plant is one which (1) has only one carpel. (2) flowers once in a life-time. (3) produces only one seed. (4) produces only one fruit. Gynoecium with fused carpels is (1) syncarpous (2) apocarpous (3) syngenecium (4) none of these

The character of flower which is represented by floral formula but not by floral diagram is (1) aestivation (2) placentation (3) position of gynoecium (4) adhesion of stamen In monoadelphous condition, stamens have (1) filaments of all united in one group but anthers are free. (2) filaments united in groups but all anthers are free. (3) anthers are fused but filaments are free. (4) both anthers and filaments are fused. In which aestivation in which members of a whorl lie close but do not overlap (1) vexillary (2) valvate (3) imbricate (4) twisted The correct sequence of types of corolla in the following figures is

(1) A – Caryophyllaceous, B – papilionaceous, C – bilabiate, D – tubular, E – bell- shaped (2) A – papilionaceous, B – bilabiate, C – tubular, D – bell-shaped, E – caryophyllaceous (3) A – bilabiate, B – papilionaceous, C– caryophyllaceous, D – bell-shaped, E – tubular (4) A – caryophyllaceous, B – bilabiate, C– papilionaceous, D – tubular, E – bell-shaped 44.

A flower is zygomorphic when (1) any transverse section divides it into two equal halves. (2) only one transverse section divides it into two equal halves. (3) every vertical section passing through its centre divides it into two equal halves. (4) only one vertical section passing through its centre divides it into two equal halves.

45.

When the anthers mature earlier than the stigma of ones own flower, the condition is known as (1) herkogamy (3) heterostyly

(2) (4)

protandry heterogamy

214 46.

BIOLOGY Consider the following statements. I. In racemose inflorescence, the flowers are borne in a basipetal order. II. Epigynous flowers are seen in rose plant. III. In brinjal, the ovary is superior. Of these statements (1) (I) and (II) are true but (III) is false (2) (I) and (III) are true but (II) is false (3) (I) and (II) are false but (III) is true (4) (I) and (III) are false but (II) is true

53.

54.

Diadelphous stamens are the characteristic features of (1) ranunculaceae

(2)

fabaceae

(3) poaceae

(4)

malvaceae

The flower in the adjacent diagram is

47. (1) homochlamydous, unisexual and hypogynous (2) homochlamydous, bisexual and epigynous (3) dichlamydous, bisexual and epigynous

Types of placentation ‘A’, ‘B’ ‘C’ and ‘D’ respectively represent (1) basal, axile, parietal and free central (2) free central, parietal, basal and axile (3) axile, basal, parietal and free central

(4) heterochlamydous, bisexual and epigynous 55.

(1) Dioecious condition, gamopetalous corolla and multiple fruit.

(4) parietal, axile, free central and basal 48.

A tetradynamous androecium has

(2) Actinomorphic flowers, free stamens and endospermic seeds.

(1) outer whorl of four smaller stamens and inner whorl of two larger stamens. (2) outer whorl of two larger stamens and inner whorl of four smaller stamens.

(3) Perennial life span, dichlamydous flower and simple fruit.

(3) outer whorl of four larger stamens and inner whorl of two smaller stamens.

(4) Simple leaves, monoecious condition and apocarpous pistil.

(4) outer whorl of two smaller stamens and inner whorl of four larger stamens 49.

50.

51.

Which one of the following sets of characters denote that plant possess all advanced morphological characters?

56.

Column I A. Pollen grains B. Pollen sacs C. Stamens

Trimerous flower, superior ovary and axile placentation is characteristics of (1) liliaceae

(2)

cucurbitaceae

(3) solanaceae

(4)

compositae

Match the following and choose the correct combination.

B

C

(1) I

II

III

one carpel

(2) II

I

III

three carpels

(3) III

I

II

(4) I

III

II

Gynoecium in the members of family—leguminosae is composed of (1) two carpels

(2)

(3) five carpels

(4)

In a flower, there are five unequal petals. The posterior petal is the largest. The two anterior petals are partially fused to form a boat-shaped structure. The two lateral petals are smaller than the posterior petal. Which one of the following characters is not associated with such a flower?

A

57.

Choose the correct option Ovary

(1) The aestivation of the petals is descendingly imbricate.

Petal Sepal

Sepal

(3) The pollination is by piston mechanism.

Thalamus

(4) The number of carpels is more. Which one of the following statement is not correct?

Stamen

Stamen

(2) The odd sepal is anterior.

52.

Column II I. Microsporangia II. Microspores III. Microsporophylls

(A)

Ovary Thalamus

(B)

(1) A plant that bears male, female and bisexual flowers is polygamous.

(1) A is primitive and B is advanced.

(2) An actinomorphic flower can be dissected into two equal halves from any plane.

(2) A is advanced and B is primitive.

(3) Superior ovary is found in hypogynous flowers. (4) That portion of the flower towards the bract is called the posterior portion.

(3) Both are advanced flower structures. (4) Both are primitive flower structures.

MORPHOLOGY OF FLOWERING PLANTS 58.

59.

Seed dormancy can be broken or its duration can be reduced by (1) scarification of seed coat (2) layering of seeds (3) change in the light, pressure and temperature (4) all of the above The given figure represents Anacardium (cashewnut). Which is the correct statement?

215 64.

65.

66.

(1) The upper part is a false fruit. (2) The upper part is a true fruit. (3) The lower part is a seed. (4) There is no fruit at all. 60.

61.

62.

63.

Which of the following correctly represents the type of fruits given below

(A) (B) (C) (D) (E) (1) A–Berry ; B–Caryopsis ; C–Drupe ; D–Sorosis; E–Aggregate (2) B–Berry ; C–Caryopsis; D–Drupe ; A–Sorosis ; E–Aggregate (3) B–Berry ; C–Caryopsis ; D–Drupe ; E–Legume ; A Aggregate (4) A–Beccate ; C–Caryopsis ; D–Drupe ; B–Sorosis ; E–Composite (5) B–Berry ; C–Caryopsis ; D–Drupe ; A–Sorosis ; E–Legume Two dry fruits (A & B) were observed. Both developed from unilocular ovaries of monocarpellary gynoecia. In fruit A, pericarp and seed coat are free. It liberated the seeds only after the disintegration of the pericrap. Fruit B dehisced dorsiventrally liberating the seeds. In the following, the former in the pair represents A and latter B. To which types of fruits A and B respectively belong? (1) achene and legume (2) nut and follicle (3) cypsella and silliqua (4) pyxidium and septicidal capsule Dorsiventral dehiscence takes place in I. legume II. follicle III. siliqua IV. capsule (1) I and III (2) I and II (3) II and III (4) II and IV The mature seeds of plants such as gram and peas, possess no endosperm, because (1) these plants are not angiosperms. (2) there is no double fertilization in them. (3) endosperm is not formed in them. (4) endosperm gets used up by the developing embryo during seed development.

67.

68.

69.

70.

71.

Endosperm, a product of double fertilization in angiosperms is absent in the seeds of (1) gram (2) orchids (3) maize (4) castor The placenta is attached to the developing seed near the (1) testa (2) hilum (3) micropyle (4) chalaza Match the following and choose correct option Group A Group B A. Aleurone layer i. Without fertilization B. Parthenocarpic fruit ii. Nutrition C. Ovule iii. Double fertilization D. Endosperm iv. Seed (1) A-i, B-ii C-iii, D-iv (2) A-ii, B-i, C-iv, D-iii (3) A-iv, B-ii, C-i, D-iii (4) A-ii, B-iv, C-i, D-iii Essential requirement for seed germination are (1) H2O and O2 (2) O2 and light (3) H2O and high temperature (4) scarification and vernalisation Choose the correct optionColumn I Column II A Apple I. Outer portion of receptacle B Coconut II. Fleshy thalamus C Jack fruit III. Thalamus & pericarp D Guava IV. Endosperm E Pineapple V. Bract, perianth & seeds (1) A – II, B – III, C – IV, D – V, E – I (2) A – V, B – III, C – I, D – IV, E – II (3) A – II, B – III, C – I, D – V, E – IV (4) A – II, B – IV, C – V, D – III, E – I (5) A – V, B – IV, C – III, D – II, E – I Why is vivipary an undesirable character for annual crop plants? (1) It reduces the vigour of plant. (2) The seeds cannot be stored under normal conditions for the next season. (3) The seeds exhibit long dormancy. (4) It adversely affects the fertility of the plant. Seeds of gram are (1) exalbuminous and epigeal (2) exalbuminous and hypogeal (3) albuminous and epigeal (4) albuminous and hypogeal The most appropriate definition of a seed is (1) A seed is an integumented sporangium with a single functional spore. (2) A seed is an integumented indehiscent megasporangium with a functional megaspore. (3) A seed is an integumented bud containing an egg. (4) None of the above.

216 72.

73.

74.

75.

76.

77.

78.

79.

BIOLOGY Seeds are regarded products of sexual reproduction because they (1) can be stored for long time. (2) are result of fusion of pollen tube. (3) are result of fusion of gametes. (4) give rise to new plants. Scutellum is a/an (1) protective covering of radicle (2) protective covering of plumule (3) endosperm of gymnosperms (4) shield-shaped cotyledon Which of the following plants is used to extract the blue dye? (1) Trifolium (2) Indigofera (3) Lupin (4) Cassia The correct floral formula of Liliaceae is O (1) Br Br⊕⊕++ P3+3 A3+3 G (3)  O (2) Br Br⊕⊕++ P3+3 A3+3 G (3) O (3) †⊕⊕++ P3+3 A3+3 G (3) OO ⊕⊕+++ PP33++33AA33++33GG(6) (4) ††⊕ (3)

Flower of fabaceae is (1) complete, zygomorphic, pentamerous (2) complete, actinomorphic, trimerous (3) incomplete, zygomorphic, trimerous (4) incomplete, actinomorphic, pentamerous Which of the following is correct with reference to flowers of family solanaceae? (1) Pentamerous, actinomorphic, unisexual, hypogynous (2) Pentamerous, zygomorphic, bisexual, epigynous (3) Pentamerous, bisexual, actinomorphic, hypogynous (4) Trimerous, actinomorphic, bisexual, hypogynous Which of the following represents the floral characters of Liliaceae? (1) Six tepals, zygomorphic, six stamens, bilocular ovary, axile placentation (2) Tetramerous, actinomorphic, polyphyllous, unilocular ovary, axile placentation (3) Trimerous, actinomorphic, polyandrous, superior ovary, axile placentation (4) Bisexual, zygomorphic, gamophyllous, inferior ovary, marginal placentation Choose the floral formula



O ⊕ (1) % %++ K 5 A10 G1 O (2) %⊕ % ++ K (5) C5 A10 G1 O (3) %⊕ % ++ K (5) C1+ 2+(2) A(9)+1 G1 O (4) %⊕ % ++ K5 C1+ 2+(2) A(9)+1 G1

80.

The floral formula of solanaceae is (1)

82.

(2) (3) (4) Br % K(5) C(5) A(10) G1 When placenta forms a ridge along the ventral suture of the ovary and the ovules are borne on this ridge forming two rows, the type of placentation is termed as (1) marginal (2) axile (3) parietal (4) free central Match the following

83.

List-I List-II (1) Spongy aril (I) Jussiaea (2) Multiple epidermis (II) Pistia (3) Respiratory roots (III) Nerium (4) Root pockets (IV) Sagittaria (V) Nymphaea A B C D (1) I III II V (2) II I IV III (3) IV II III I (4) V III I II Match the following-

81.

84.

(A)

List-I Coleorhiza

(B)

Apogamy

(C)

Indusium

(D)

Caudex

List-II (I) D e v e l o p m e n t o f sporophyte directly from gametophyte without intervention of gametes (II) D e v e l o p m e n t o f gametophyte directly from sporophyte without the involvement of reduction division. (III) An unbranched columnar stem with a crown of leaves. (IV) Protective covering of radicle (V) Protective structure of a sorus.

A B C D (1) V II IV I (2) IV I V III (3) III V II IV (4) II III I V Which of the following are not characteristic features of fabaceae? (1) Tap root system, compound leaves and raceme inflorescence. (2) Flowers actinomorphic, twisted aestivation and gamopetalous. (3) Stamens 10, introrse, basifixed, dithecous. (4) Monocarpellary, ovary superior and bent stigma.

MORPHOLOGY OF FLOWERING PLANTS

217

ANSWER KEY EXERCISE 1 : NCERT BASED QUESTIONS 1.

(3)

2.

(3)

3.

(1)

4.

(4)

5.

(1)

6.

(4)

7.

(1)

8.

(1)

9.

(4)

10.

(1)

11.

(1)

12.

(1)

13.

(1)

14.

(1)

15.

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(3)

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23.

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24.

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27.

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28.

(3)

29.

(2)

30.

(2)

31.

(3)

32.

(3)

33.

(4)

34.

(2)

35.

(1)

EXERCISE 2 : WINDOW TO COMPETITIVE EXAMS

141. (4)

142. (1)

143. (1)

144. (3)

145. (3)

146. (4)

147. (1)

148. (3)

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150. (4)

151. (1)

152. (1)

153. (3)

154. (3)

155. (3)

156. (2)

157. (3)

158. (2)

159. (3)

160. (4)

161. (1)

162. (3)

163. (4)

164. (1)

165. (4)

166. (2)

167. (3)

168. (2)

169. (1)

170. (1)

171. (2)

172. (4)

173. (3)

174. (1)

175. (3)

176. (4)

177. (3)

178. (1)

179. (3)

180. (2)

181. (3)

182. (4)

183. (2)

184. (3)

185. (2)

186. (3)

187. (4)

188. (2)

189. (4)

190. (2)

192. (3)

193. (4)

194. (1)

195. (3)

1.

(3)

2.

(4)

3.

(2)

4.

(4)

5.

(2)

191. (1)

6.

(4)

7.

(2)

8.

(1)

9.

(2)

10.

(1)

196. (1)

11.

(4)

12.

(3)

13.

(1)

14.

(4)

15.

(3)

16.

(3)

17.

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18.

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20.

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21.

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23.

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24.

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25.

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26.

(1)

27.

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28.

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29.

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30.

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31.

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33.

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34.

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35.

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37.

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38.

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(1)

100. (1)

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(1)

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(1)

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133. (4)

134. (4)

135. (1)

136. (2)

137. (4)

138. (1)

139. (2)

140. (4)

EXERCISE 3 : TEST YOURSELF 1.

(1)

2.

(3)

4.

(4)

Halophytes

3. or

Raxburghiana,

(4) mangroves

like

Sonneretia

Rhizophora, etc.,

have

pneumatophores and vivipary. 5.

(4)

6.

(1)

7.

(4)

8.

(2)

9.

(3)

Stolons are special kind of runners, which initially grow upwards like ordinary branches and then arch down to develop new daughter plants on coming in contact with the soil. Sucker is a sub-aerial branch, that arise from the main stem. Initially, it grows horizontally below soil surface and later grows obliquely upward.

10.

(1)

11.

(1)

Starch is insoluble in water but it is useful for storage. During night, it is stored in various storage organs but it is mainly found in underground stems (or tubers), in the seeds of cereals (e.g., wheat, maize, rice, etc) and in fleshy roots.

12.

(3)

13.

(4)

14.

(2)

15.

(2)

Potato is a modification of stem and sweet potato is a modification of root.

16.

(2)

In caudex, only the terminal bud functions and lateral buds remain dormant. eg, palms. Decumbent stems have branches which after growing horizontally for some length, grow vertically

218

BIOLOGY upwards, eg, Tridax, Portulaca. Sucker is grow

32.

(2)

33.

(2)

34.

(1)

35.

(2)

36.

(4)

obliquely upward from the main stem producing

37.

(3)

38.

(2)

39.

(1)

40.

(3)

41.

(1)

roots from the underground nodes, eg, Mentha.

42.

(2)

43.

(1)

44.

(4)

45.

(2)

46.

(3)

Saraca shows helicoid type of uniparous cymose

47.

(3)

48.

(4)

49.

(1)

50.

(2)

51.

(4)

branching.

52.

(4)

53.

(2)

54.

(3)

55.

(1)

56.

(2)

57.

(1)

58.

(4)

59.

(1)

60.

(4)

61.

(1)

17.

(1)

18.

(2)

19.

(3)

20.

(1)

21.

(2)

In isobilateral leaf, both adaxial and abaxial surface

62.

(1)

63.

(4)

64.

(2)

65.

(4)

66.

(2)

are uniform in colour and show similar structure.

67.

(1)

68.

(4)

69.

(2)

70.

(2)

71.

(2)

Both surface receive light. e.g., Monocots (Maize).

72.

(3)

73.

(4)

74.

(2)

75.

(2)

76.

(1)

80.

(1)

81.

(1)

22.

(1)

23.

(4)

24.

(4)

25.

(1)

26.

(4)

77.

(3)

78.

(3)

79.

(3)

27.

(2)

28.

(1)

29.

(2)

30.

(2)

31.

(1)

82.

(4)

83.

(2)

84.

(2)

Chapter

6

Anatomy of Flowering Plants While going through the chapter pay special attention to the following – Terms and definitions – (i) Promeristem (ii) Dermatogen (iii) Periblem (iv) Plerome (v) Idioblast (vi) Aerenchyma (vii) Prosenchyma (viii) Phellem (ix) (x) Epiblema (xi) Laticiferous tissue (xii) Differences – (1) Meristematic tissue and permanent tissue (2) Promeristem, primary meristem and secondary meristems (3) Apical, intercalary and lateral meristems (4) Dermatogen, periblem and plerome (5) Parenchyma, collenchyma and sclerenchyma (6) Amphicribral and amphivasal vascular system (7) Dorsiventral and isobilateral leaf (8) Spring and autumn wood (9) Heart wood and sapwood

Phelloderm Trichomes



N. Grew. Father of plant anatomy and used the term tissue for the first time.

   

K.A. Chaudhary. Indian plant anatomist. Anatomy deals with internal organization of plants as observed after section cutting. Nageli is regarded as Father of Modern Anatomy. The internal structure of most plants (except some lower plants) is complex and different types of cells form the plant body. These cells are in groups to form tissue which, perform definite function.



THE TISSUE 

A group of structurally similar or dissimilar cells that perform a common function and have a common origin is called a tissue. A plant is made up of different kinds of tissues. The complex tissues are, however, composed of different kinds of cells and they perform different types of functions.



Each tissue has a specific function to perform and different types of tissues of a plant body function in co-ordination with one another.

At a Glance            

Tissue

Types of tissue

Meristematic tissues

Different types of meristematic tissue Simple permanent tissue

Complex permanent tissue Special permanent tissue Epidermal tissue system Ground tissue system

Vascular tissue system

Anatomy of monocotyledonous and dicotyledonous stems, root and leaf Secondary growth in dicotyledonous stems and roots.

220

BIOLOGY

Kinds of Plant Tissues 

Plant tissues are broadly classified on the basis of stages of development into two categories: •

Meristematic tissue : They have the ability to divide.

•

Permanent tissue : They have lost the ability to divide.

MERISTEMATIC TISSUE 

Cells which are capable of active cell division are called meristematic cells. These tissues are found in growing regions of plants. e.g., meristem at apex of stem, root, leaf primordia and vascular cambium, etc.



The chief characteristics of meristematic cells are: •

The cells of meristem are always living.

•

Meristematic cells are simple, immature, and isodiametric (same length, width and height, mostly rounded/ oval/ polygonal or rectangular).

•

They retain power of division.

•

They are without intercellular spaces.

•

They have dense cytoplasm with prominent nuclei.

•

Only cellulosic primary cell wall is present.

•

They have no reserve food material and further no ER and plastids in them.

•

Vacuole is small or absent.

Classification of Meristematic Tissues 



Meristematic tissues may be classified on the basis of : •

Mode of origin and development and

•

Position in the plant body.

Meristems based on origin and development On this basis meristems can be divided into following three types.

Fig. 6.1 L.S. of axis showing the positions of meristems.

•

Promeristem (primordial meristem) : These are group of cells which represent primary stages of meristematic cells. They are present in a small region at the tips of radicle and plumule. They give rise to primary meristems.

•

Primary meristem : Primary meristems originate from promeristem that continue to divide to form different tissues. These cells are always in active state of division and give rise to primary permanent tissues for growth in length as well as width e.g., apical meristems, intercalary meristems, lateral meristems (intra-fascicular cambium in the vascular bundle of dicot stem).

•

Secondary meristems : Secondary meristems developed from primary permanent tissue. They are not present from the beginning of the formation of an organ but develop at a later stage by differentiation and acquire power of division. e.g., interfascicular cambium in stem, cambium in roots and also cork cambium (phellogen).

ANATOMY OF FLOWERING PLANTS 

221

Meristematic tissues based on position in plant body On the basis of position, the meristematic tissues can be divided into the following three types: •

Apical meristem

•

Intercalary meristem

•

Lateral meristem



Apical meristem. It is situated at the shoot apex and the root apex. It includes both the Connecting Concepts promeristem and the primary meristem. Apical meristems give rise to primary permanent  To propagate virus free plants tissues which bring about the elongation of the stem and the root. This meristem is apical through tissue culture techniques in stem and subterminal in roots due to presence of root cap (calyptra). The cells of this apical meristem is used. region are small, unspecialized and divide to cause primary growth of stem and root. It is never used up during the growth. Leaf primordia grow into leaf by activity of apical meristems.



Intercalary meristem. These tissues are found in between the permanent tissues. These tissue are actually parts of the apical meristem which get detached from it during the growth of stem and root in length. Intercalary meristem is present at the base of internodes, e.g, in grasses (Gramineae) or at the base of leaves, e.g., in Pinus or at the base of nodes, e.g., mint or Mentha (Labiatae).



Lateral meristem. These meristems are present along the lateral sides of stem and roots. Lateral meristem divides only periclinally or radially and is responsible for increase in girth or diameter. It includes vascular cambium and cork-cambium.

Meristem on the basis of functions The first formed meristem (promeristem) gets differentiated into following three regions –  Protoderm or Dermatogen: It is the outermost layer meant for producing the single layered epidermis, hairs, velamen, stomata i.e., epidermal tissue system.  Ground meristem or Periblem: It produces hypodermis, cortex and endodermis or ground tissue system. 

Procambium or Plerome: It is the innermost part of the meristem. It gives rise to the stele which comprises primary vascular tissues and ground tissues like pith, medullary rays and the pericycle. PROMERISTEMS AND THE TISSUE SYSTEM Meristem

Dermatogen

Permanent region Epidermis

dermatogen periblem plerome

Fig. 6.2 L.S. of root showing zonation.

plerome periblem dermatogen

Tissue system Epidermal tissue system

calyptrogen Hypodermis Periblem

Plerome

Cortex

Stele

General cortex Endodermis 1. Pericycle 2. Pith rays 3. Pith Vascular bundle 1. Phloem 2. Cambium 3. Xylem

root cap Ground tissue system

Fig. 6.3 L.S. of root apex.

Vascular tissue system

PERMANENT TISSUES 

Permanent tissues are formed as a result of division and differentiation in meristematic tissues.



These tissues are composed of mature, living or dead cells that have lost their ability to divide.

222

BIOLOGY 

The cells of these tissue may be thin-walled or thick-walled. The thin walled tissues are generally living whereas the thick -walled tissues may be living or dead.



They have undergone growth and differentiation to attain a permanent position, function, shape and size. They are called primary permanent tissues if they are derived from apical meristem and called secondary permanent tissues when derived from lateral meristem.



Permanent tissues are of two types : (i) Simple tissue (ii) Complex tissue

Simple Permanent Tissue 

These tissues are a collection of similar cells that perform a common function. These tissues are of 3 types: (a) Parenchyma (b) Collenchyma (c) Sclerenchyma

Parenchyma 

It is simplest, unspecialized, most primitive, most abundant permanent tissue (found in all organs of the plant).



Parenchyma cells are living, thin-walled, isodiametric (all sides equal) and appear oval or spherical in shape. Sometimes they become polygonal as a result of pressure of the neighbouring cells.



The spherical parenchyma cells are loosly arranged with large intercellular spaces.

Nucleus

 Intercellular space 

Vacuoles



Cytoplasm

Fig. 6.4 Parenchyma

Entire mesophyll of the leaf, cortex and pith of the roots and the stems are parenchymatous. The cell wall is thin and made up of cellulose. It helps in storage of food, conduction of substances, provides turgidity to softer parts of plants. Chlorenchyma (parenchymatous cells having chloroplasts) participates in photosynthesis. It is present in mesophyll cells of leaves and differentiated into palisade parenchyma and spongy parenchyma. It is also present in cortex of young stem. • Palisade parenchyma: It is a type of chlorenchyma in which cells are elongated. In heliophytes (sun loving), more layers of palisade parenchyma are found as compared to sciophytes (shade loving). • Spongy parenchyma: It is also a type of chlorenchyma with cells of irregular shapes and sizes, thus leaving numerous intercellular spaces.



Aerenchyma : A parenchyma with well developed intercellular spaces which forms a connected system throughout the entire plant is known as aerenchyma. It is common in submerged hydrophytes.



Prosenchyma : Elongated fibre like thick walled parenchyma for rigidity and strength.



Guard cells are modified parenchyma with chloroplasts.

Functions    

The main function of parenchyma is storage of food. Parenchyma always retains its meristematic character. It becomes meristematic during wound healing, formation of adventitious roots, grafting, etc. Photosynthesis, respiration, secretion, assimilation, etc are some of the important processes which occur in parenchymatous cells. In fleshy stems and leaves, parenchyma cells function as water storage tissue e.g. Opuntia, Euphorbia.



In hydrophytes, aerenchyma makes the plants buoyant due to the presence of air and also gaseous exchange is facilitated.



Chlorenchyma (parenchymatous cells that develop chloroplasts) participates in photosynthesis.

ANATOMY OF FLOWERING PLANTS 

Xylem and phloem parenchyma are meant for storage and lateral conduction of water/ food.



Sometimes such cells start to divide e.g., Cork cambium, root cambium, and help the plant in secondary growth and formation of cork.

223

Collenchyma  

Thickening on corners due to deposition of It is living mechanical tissue, found beneath the epidermis (i.e., hypodermis) of herbaceous cellulose and pectin

Collenchymatous cells are longer than parenchyma cell. dicot stem.



The intercellular spaces in this tissue are absent because in intercellular spaces at the corner of cells thickenings of cellulose and pectin develop due to which the cell wall become rigid and thick at corners.



They are absent in dicot roots, monocots and underground parts.

Functions 

It provides mechanical support to the organs and due to its peripheral position in stems and resists bending and pulling action of wind.



Due to presence of pectin in cell wall, collenchyma can hold large amount of water.



When chloroplasts are present it takes part in photosynthesis.

Fig. 6.5 Collenchyma

Sclerenchyma 

These are dead, mechanical tissue and act as skeleton in plants.



It develops either from the procambium or secondarily from parenchyma due to secondary wall deposition.



It is hardest plant tissue, made up of highly thick walled cells in which nucleus and cytoplasm are absent. This uniform thicknening is made up of mainly lignin and cellulose or both. Cotton and flax fibres are rich in cellulose whereas jute and coir fibres are rich in lignin.



Two types of cells are included in sclerenchyma i.e., sclerenchymatous fibres and stone cells (sclereids).



Sclerenchymatous fibres:



•

Fully developed fibres are long and tapering at the ends.

•

In some cases the cell becomes so much lignified that the lumen is greatly reduced.

•

They provide great strength and flexibility.

•

The fibres are present in hypodermis of monocot stem, pericycle of many dicots, secondary wood, vascular bundle sheath of monocot stems, and hypodermis of many leaves.

Stone cells (Sclereids): •

They are lignified, extremely thick walled so that the lumen of the cells is almost obliterated.

•

It provides grittiness to fleshy fruits.

•

They form part of seed coat in some members of leguminoseae. They also provide mechanical strength to a softer tissue.

Functions 

The main function of sclerenchyma is to provide mechanical strength.



Sclereids provide grittiness in the pulp of many fruits like guava, pear, sapota, stiffness and hardness to seedcoat, nut and endocarp of walnut and coconut.



In leaves, sclerenchyma provides rigidity and saves it from collapsing.

Fig. 6.6 Sclerenchyma

224

BIOLOGY

COMPLEX PERMANENT TISSUES 

A complex tissue can be defined as a collection of different types of cells performing a common function.



Xylem and phloem are the complex permanent tissues found in vascular tissue of all vascular plants.



Xylem is mainly responsible for conduction of water and minerals from the roots to the top of plants (unidirectional).



It also provides mechanical support to the plant. Phloem mainly carries food. Both xylem and phloem are assemblage of living and dead cells and may be primary or secondary in origin.

Simple perforation plate

Xylem (Wood) 

Xylem is water conducting tissue. It is also known as hadrome.



Xylem is made of 4 types of cells i.e., tracheids, tracheae (vessels), xylem fibres and xylem parenchyma.



Only xylem parenchyma is living and all other three are dead tissues.



Both tracheids and vessels are thick-walled. V Vessels and tracheids are called tracheary elements because they conduct sap.

Simple Tracheids perforation • The cells are long, tubular with tapering, chisel like ends. The cell wall is lignified. plate Thickening in wall may be scalariform, annular, reticulate and pitted. Tracheids are generally with bordered pits.

Border pits Tracheids

Vessels Fig. 6.7 Xylem

Connecting Concepts  Vessels are generally upto 10 cm in length but longest vessels are found in Eucalyptus and oak (Quercus), which are from 2 metre to 5 metre in length.  Vesselless angiosperms : Although vessels are characteristic features of angiosperms but there are certain angiosperms where vessels are absent. Such vesselless angiosperms belong to families : 1. Winteraceae (e.g., Wintera). 2. Tetracentraceae

•

The tracheids are dead (without cytoplasm and nucleus) at maturity.

•

The tracheids form a long row placed one above the other.

•

The main function of tracheids is to conduct water but due to their thick and hard walls they also provide mechanical support.

Tracheae (Xylem vessels) • Tracheae differ from tracheids in being cell fusions arising through the dissolution of end walls. • Thus, vessel is syncytial (multicellular) in origin. Vessels are also called septaless tracheids. • Vessels is an elongated tube like structure that is composed of row of cells placed one above the other with their transverse walls absent. • The walls of vessels are lignified and less thicker than tracheids. The lumen is wider than tracheids. • The thickenings may be annular, spiral, scalariform and reticulate etc. • A wood with xylem vessels is called heteroxylous or porous wood. Wood (Xylem) fibres • They are long, narrow and tapering at both ends.

(e.g., Tetracentron). 3. Trochodendraceae

•

The walls are lignified.

•

They provide only mechanical support.

Wood (Xylem) parenchyma • These are thin walled (cellulose) living cells.  Besides, vessels are absent in stem and leaves of Yucca and Dracaena. • They are present in primary as well as secondary xylem. (e.g., Trochodendron).

 There are some non-angiosperms where vessels are present, e.g., some  species of Selaginella, two species of Pteridium, (pteridophytes) and order Gnetales of gymnosperms (e.g.,  Gnetum, Welwitschia and Ephedra).

•

They store food material and also involved in short distance lateral transport of sap.

The first formed xylem is called protoxylem and the later formed xylem is called metaxylem. The vessels and tracheids of protoxylem are small and have annular or spiral thickenings on their secondary walls. In protoxylem, lignification occurs before the completion of elongation.

ANATOMY OF FLOWERING PLANTS 

    

225

Vessels and tracheids of metaxylem are bigger and have scalariform, reticulated and pitted thickenings on their secondary walls (pitted thickenings are common). In metaxylem, lignification occurs after the completion of elongation. Fibres often occurs in metaxylem. Depending upon position of protoxylem, xylem can be exarch, endarch or mesarch Exarch (centripetal): Xylem matures from outside to inside and protoxylem lies towards the outside of vascular bundle, e.g., roots. Endarch (centrifugal): Xylem matures from inside to outside and protoxylem lies towards the innerside of vascular bundle, e.g., stem. Mesarch : Protoxylem lies in the middle of metaxylem, e.g., ferns. Secondary xylem is derived from cambium during secondary growth. It has axial or vertical system (tracheids, vessels, xylem fibres and xylem parenchyma) and ray or horizontal system (ray parenchyma). It is neither exarch or endarch and not differentiated into proto or metaxylem. That is why, it is difficult to distinguish secondary xylem of root from stem after secondary growth.

Phloem (Bast)   

Phloem is also a conducting tissue that transports food materials, usually from leaves to other part of the plants (bidirectional). It is a complex tissue made up of 4 kinds of cells in angiosperms, these are sieve elements, companion cells, phloem fibres, phloem parenchyma. Phloem of gymnosperms have albuminous cells and sieve cells. They lack sieve tubes and companion cells.

Sieve element •

•

• •

The sieve elements in angiosperms are sieve tubes arranged one above the other in distinct linear rows and have sieve plates (oblique or transverse perforated septa) on their end walls. These are associated with companion cells. A mature sieve element possesses a peripheral cytoplasm and a large vacuole but lacks nucleus. The functions of sieve tubes are controlled by the nucleus of companion cells. In gymnosperms and pteridophytes, the sieve elements have sieve plates to their lateral walls. Companion cells are absent and there is no distinct arrangement of sieve cells in linear rows – such sieve elements are called sieve cells. During winter, in temperate plants the pores in sieve plate get temporary plugged by insoluble carbohydrate called callus to prevent transport of food. The callus is soluble and disappears when contents of the sieve tube are dilute. At the advance of spring, this substance dissolves and the pores open again. On injury, sieve tubes collapses and sealed off by callose and protein.

Companion cells • • • • •

Companion cell is a long, narrow, thin walled cell that is usually attached to the lateral side of sieve tube. It contains cytoplasmic contents and a large nucleus. They are supposed to help in maintaining pressure gradient in sieve tubes. They are absent in gymnosperms and pteridophytes. In gymnosperms, companion cells are replaced by parenchyma cells called albuminous cells (or strasburger cells). Companion cells are absent in protophloem. The companion cells and sieve tubes maintain close cytoplasmic connections with each other through fine pits which are present between their common longitudinal walls.

Phloem fibres •

These are sclerenchymatous dead cells that provide mechanical strength. They have thick wall with simple pits.

•

These are absent in leaves, roots and primary phloem.

Connecting Concepts  In primary phloem of herbaceous plants, a single companion cell is associated with a single sieve tube element whereas in phloem of woody plants, many companion cells are associated with a single sieve tube element.  Austrobaileya is an angiosperm without companion cell.

226

BIOLOGY •

The fibres from secondary phloem are commercially important as they are used for making ropes and coarse textile.

Phloem parenchyma • These cells are living, thin walled parenchyma cells that store food, latex, tannin, crystals, etc.



•

They are intermingled with sieve tubes.

•

They are absent in monocots and in some dicots (e.g., Ranunculus).

The first formed primary phloem consists of narrow sieve tubes and referred as protophloem and the later formed phloem has bigger sieve tubes and referred as metaphloem. A B Sieve tube Sieve plate Sieve pore

Sieve tube

Phloem fibres Phloem parenchyma cells Companion cell

Callose Sieve plate Fig. 6.8 Phloem

Connecting Concepts

SPECIAL TISSUES

 Water-secreting glands or hydathodes or Water-stomata :  Many plants like Garden Nasturtium, Colocasia, Pistia and Eichhornia possess special structures, which exude impure  water in the form of small drops (Guttation).  This guttation is through certain pores called hydathodes, which are present at the margins of the leaf. These are always open and large in size.





Connecting Concepts

These tissues perform special functions i.e., secretion and excretion in plants. They are found in pith, cortex, xylem and phloem. These tissues are of two types i.e., glandular tissue and laticiferous tissue. Glandular tissues A gland is a specialized group of cells that are endowed with the capacity to secrete or excrete products, e.g. secretion of resin gum, oil and latex. These are of two types: • External glands : These generally occur in the epidermis of stem and leaves as glandular outgrowth, e.g., glandular hair, as in Urtica dioica stinging hairs, nectar secreting and enzyme secreting glands e.g. Drosera, Nepenthes etc. • Internal glands: These are of several types, e.g., oil glands in Citrus, Eucalyptus, resin glands in Pinus, Cedrus, water secreting glands. Laticiferous tissues are mainly composed of thin walled, elongated, branched and multinucleate tube like structures that contain colourless milky or yellow coloured juice called latex. They are scattered throughout the ground tissue of the plant and contain stored organic matter in the form of starch, rubber, tannins, alkaloids, mucilage enzymes, protein, etc.

THE TISSUE SYSTEM Each system usually consists of only one tissue or an association of tissues which perform a

 In Hevea (rubber), laticifers occur in common function. There are three main tissue systems : secondary phloem and in papaya, both • Epidermal tissue system in xylem and phloem.

•

Fundamental or ground tissue system

•

Vascular tissue system

ANATOMY OF FLOWERING PLANTS

227

The Epidermal Tissue System 

This forms the outer covering of plant. It is in direct contact with the external environment.



It performs manifold function, e.g., protection, absorption, excretion, secretion, gaseous exchange and control of transpiration, etc.



Epidermal tissue system includes :



Epidermis: It is the outermost layer of all organs of primary plant body.





•

Epidermis is protective in function.

•

It is made up of elongated, compactly arranged single layer of cells.

•

However, in leaf of Nerium, it is multi layered.

•

The outer wall of epidermal cell is thick, inner is thin and radial walls are thick above and thin below.

•

Epidermis of root differs in origin, structure and function and called as epiblema or piliferous layer.

•

Cells constituting epidermal cells are parenchymatous with little quantity of cytoplasm with large vacuole.

•

The outer wall of epidermal cells contain a fatty substance called cutin and form cuticle on the epidermis. Cuticle prevents the loss of water. It is absent in roots.

Stomata: Stomata are tiny pores that are found on the epidermis of leaves, stem and some fruits. •

Stomata are absent in roots.

•

Stomata helps in gaseous exchange at the time of respiration and photosynthesis.

•

Stomata are composed of two bean-shaped epidermal cell called guard cells which encloses stomatal pore.

•

In grasses, guard cells are dumb bell shape. The two guard cells attached to each other at both ends.

•

Unlike other epidermal cells, the guard cells have chloroplasts and the outer walls of guard cells (away from the stomatal pore) are thin and the inner walls (towards the stomatal pore) are highly thickened.

•

The guard cells may be surrounded by varying number of specialized epidermal cells called subsidiary cells or accessory cells. The guard cells control the opening and closing of stomata, which in turn, regulate the loss of water from the leaves to the atmosphere through transpiration.

•

The stomatal aperture, guard cells and the surrounding subsidiary cells are together called stomatal apparatus.

•

In dicot leaves, stomata are scattered whereas in monocots, these are arranged in rows. Further in dicots these are present generally on lower epidermis whereas in monocots, on both surfaces.

•

In free floating hydrophytes, stomata are present on upper epidermis, whereas in submerged hydrophytes, these are absent or non-functional (in algae and fungi stomata are totally absent.)

•

In xerophytes, stomata are of sunken type so as to reduce water loss by transpiraiton.

Epidermal appendages (trichomes and epidermal hairs): •

Numbers of hairs are found on epidermis.

•

The root hairs are unicellular and represent the extention of epidermal cells.

•

On stems, epidermal hairs are called trichomes.

•

In shoot system, they are usually multicellular. They may be soft or stiff, branched or unbranched. Sometimes they are secretory.

Check Point Give the alternate name for the following tissue – (i) Dermatogen (ii) Periblem (iii) Plerome (iv) Piliferous layer (v) Bast

228

BIOLOGY •

They help in retarding the rate of transpiration.

•

Root hairs help in absorption of water and minerals from soil.

Ground (Fundamental) Tissue System 

All tissues except epidermis and vascular bundle constitute the ground tissue.



It consists of simple tissues such as parenchyma, collenchyma and sclerenchyma.



In dicot stems, roots and monocot roots (in which vascular bundles are in a ring), the ground tissues constitute the following parts :



Cortex : It is differentiated into the following tissues. •

Hypodermis : Generally one or two layers of continuous or discontinuous tissue present below epidermis, is called hypodermis.

•

In dicot stem, hypodermis is collenchymatous and in monocot stem, sclerenchymatous. It is protective in function.

•

General cortex : It is few to many layered thick and in most of the cases, it is thinwalled and parenchymatous with intercellular spaces. The cells of cortex contain starch grains, oil, tannins and crystals of various types.

•

Sometimes in young stem, chloroplasts develop in cortical cells, which is called chlorenchyma. In hydrophytes, cortex is aerenchymatous (with air cavities).

•

It provides mechanical support and stores food material.

•

Endodermis : Endodermis is single layered structure which separates cortex from stele.

•

The cells of endodermis are barrel-shaped without inter-cellular spaces, living and containing starch. (Hence it is known as starch sheath).

•

Radial and tangential walls of endodermal cells possess thickenings of lignin, suberin and cutin in the form of strips or bands, which are known as casparian bands or casparian strips (as it were discovered by Caspar).

•

A well defined endodermis is constant feature of roots (not in stem).

•

There are thick-walled and thin-walled cells in endodermis. Thin-walled cells are known as passage cells or transfusion cells, which are present opposite protoxylem.

•

It acts as a watertight dam between vascular and nonvascular regions, stores starch, serve as protective layer and maintains root pressure.

Connecting Concepts  Orchids root : In the aerial roots of orchids, outer most layer is made up of multilayered velamen tissue, which are large, dead cells with fibrous thickenings. These contain air in dry conditions and absorb moisture when atmosphere is wet. Outermost layer of velamen is limiting membrane having cuticle and inner to velamen is exodermis (outermost layer of cortext), which is have thick and thin-walled cells. Thin-walled cells are called passage cells. The main function of aerial root of orchid is to absorb moisture and so they are known as hygroscopic roots.

Connecting Concepts



 In Smilax root, pericycle is multilayered and sclerenchymatous. Pericycle is present in most of the roots except in roots of parasitic plants and hydrophytes.

Pericycle : It is single or few layered parenchymatous or rarely sclerenchymatous cells. •

In some cases like sunflower stem, pericycle is heterogenous, i.e., composed of parenchyma and sclerenchyma.

•

Sclerenchymatous pericycle is mechanical in function whereas parenchymatous pericycle is storage in function.

•

In angiosperms, pericycle gives rise to lateral roots.

The Vascular Tissue System 

The central cylinder of the shoot or root surrounded by cortex is called stele. The varying number of vascular bundles formed inside the stele constitutes vascular tissue system.



Each vascular bundle is made up of xylem and phloem with or without cambium.



The vascular bundles in dicot stems and roots as well as monocots roots are arranged in a ring while in monocot stem they are scattered in general ground tissue.

ANATOMY OF FLOWERING PLANTS

229

Elements of a vascular bundle 

Xylem : In dicot and monocot stem, the development of xylem takes place towards periphery i.e., protoxylem is formed towards center and metaxylem towards the periphery. This is called centrifugal xylem and this condition is called endarch condition.



Phloem: In stem, the phloem is away from the center towards the periphery and situated above the xylem. The phloem parenchyma is absent in monocots.



Cambium: A thin strip of primary meristem is present in between xylem and phloem in dicotyledonous stems. It is called vascular cambium. In monocot stem, cambium is absent. •

In roots, the xylem and phloem are not aggregated in a common vascular bundle but form separate strips that alternate each other.

Phloem

Types of Vascular Bundles

Cambium

There are three types of vascular bundle i.e., radial, conjoint and concentric. 

Radial: It is the most primitive type of vascular bundle. In this type of vascular bundles, alternate strands of phloem and xylem are present on different radii. This type of vascular bundle is found in roots.

the inner side. If cambium is present in between the phloem and the xylem, it is called open and if the cambium is absent, it is called closed.

• 

Collateral open

Outer phloem Outer Conjoint : Here, xylem and phloem are present on the same radius. This type of vascular cambium Xylem bundle is found in stems and leaves. Inner cambium • Such vascular bundles are of two types i.e., collateral and bicollateral. Inner phloem • Collateral : It has one patch of phloem on the outer side and one patch of xylem on

• 

Xylem closed

Phloem

Xylem

Bicollateral

Amphivasal

Phloem

Bicollateral : It has an outer and an inner phloem as well as an outer and inner cambium. The xylem occurs in the middle of the vascular bundle.

Concentric: In this vascular bundle, either xylem surrounds the phloem or phloem surrounds the xylem. Concentric vascular bundles are of two types— •

Amphicribral (hadrocentric or centroxylic) : The xylem is surrounded by phloem, e.g., Ferns.

•

Amphivasal (leptocentric or centrophloic) : The phloem is surrounded by xylem, e.g., Dracaena, Yucca.

ANATOMY OF DICOTYLEDONOUS AND MONOCOTYLEDONOUS PLANTS

Xylem Amphicribral

Radial

Fig. 6.9 Types of Vascular Bundles

Connecting Concepts

 The root hairs are not permanent Main characterstics of internal structure of root are :structures. Active life span is upto 7  On outer side, there is single layered epiblema or piliferous layer or rhizodermis, which days. Aferwards they shrivel. The older epiblema cells then become cutinised bears unicellular root hairs. and suberised.

•

Cuticle and stomata are absent. (Root hair arise from epiblema).



Inner to epiblema is multilayered cortex.



Inner to cortex is present single layered distinct endodermis or starch sheath with distinct casparian strips or bands.



Inside the endodermis, there is present distinct pericycle.



Vascular bundles in root are radial.



Xylem is exarch or centripetal.



Phloem is made of sieve tubes, companion cells and phloem parenchyma. (Phloem parenchyma is absent in monocot root).



In the centre, pith is well developed or ill defined.

Connecting Concepts  Bicollateral vascular bundles are found in families Cucurbitaceae, Solanaceae and Myrtaceae.

230

BIOLOGY

DICOTYLEDONOUS ROOTS Connecting Concepts

Internally, a dicotyledonous root exhibits the following five zones in a transverse section :  Epidermis or piliferous layer :

 Reasons for Identification of dicot root. (i) Presence of root hairs.

•

It is the outer protective layer of very compact cells. It is single layered.

•

The epidermis or epiblema of roots lack both the cuticle and guard cells. Stomata are completely absent.

(ii) Endodermis with casparian strips.



(iii) Absence of pith.

It produces a number of unicellular root hairs.



Cortex : The cortex is well developed in the roots. The cells of the cortex are multilayered parenchymatous with large intercellular spaces.

(iv) Radial vascular bundles less than eight. (v) Exarch xylem.







Endodermis : •

It is innermost layer of the cortex.

•

The cells of the endodermis are barrel shaped.

•

They have thickened strips on radial and transverse walls. The thickened strip has deposit of lignin, suberin or cutin known as casparian strip.

•

Casparian strips do not allow water and mineral ions to pass through it.

•

There are few thin-walled cells in the endodermal layer. They are called passage cells. They are present opposite to protoxylem elements to permit an easy passage of water.

Pericycle : •

It is outer boundary of stele.

•

It is single-layered or multilayered and consists of parenchyma cells. It gives rise to lateral roots as well as cork cambium.

•

It gets lignified in older roots in monocotyledons. The pericycle is absent in some aquatic plants and parasites.

Stele : All tissues on the innerside of the endodermis such as pericycle, vascular bundles and pith constitute the stele are usually two to four xylem and phloem patches constituting radial vascular bundle. Later, a cambium ring develops between the xylem and phloem. •



Xylem is exarch.

Pith : It is either absent or very small and centrally placed. •

The parenchymatous cells which lie between the xylem and the phloem are called conjuctive tissue. Root hair

Epiblema

Root hair Epiblema Cortex Cortex Endodermis Pericycle Endodermis Pericycle

Phloem Protoxylem Metaxylem Pith

Phloem Metaxylem Protoxylem

(a)

Pith (b)

Fig. 6.10 (a) T.S. of young root of Gram (dicotyledonous roots) (b) T.S. of Maize (monocotyledonous roots)

ANATOMY OF FLOWERING PLANTS

231

MONOCOTYLEDONOUS ROOTS

Connecting Concepts

Anatomy of monocot root is very much similar to dicot roots but they do not undergo any  Reasons for monocot root. secondary growth.

Identification

of

(i) Presence of root hairs.



Epiblema or piliferous layer : It is a single layer of thin-walled parenchyma cells. It has (ii) Endodermis with passage cells. several unicellular hairs.



Cortex : It is similar to that of dicot root.



Endodermis : It is similar to that of dicot root.



Pericycle : It is also similar to that of dicot root. In old roots the cells become lignified.



Vascular bundles : Like dicot roots they are also radial and exarch. The number of vascular bundles, however is more than six (polyarch). Phloem is made up of sieve tubes and companion cells. Phloem fibres are rare. Phloem parenchyma is absent. Protoxylem is in contact with pericycle. Metaxylem is towards the inner side. Xylem is formed of vessels and xylem parenchyma. Fibres and tracheids are very few.



Pith : It is large and well developed.



Monocotyledonous roots do not undergo any secondary growth.

(iii) Presence of pith.

(iv) Radial vascular bundles more than eight. (v) Exarch xylem. (vi) Occurrence of exodermis.

Difference between dicot and monocot roots : S.No. Dicot Roots 1. Epiblema persistent.

Monocot Roots Epiblema degenerates alongwith shrivelling of root hairs.

2.

An exodermis is absent.

3.

Secondary growth occurs in older roots.

An exodermis is formed from outer layers of cortex after the degeneration of epiblema. Secondary growth is absent.

4.

Endodermis does not develop thickenings. Endodermis develops thickenings in older parts of the root.

5.

Passage cells are absent.

6.

Pericycle remain parenchymatous.

7.

9.

Pericycle has three functions – formation Pericycle produces only lateral roots. of lateral roots, vascular cambium and cork cambium. The number of vascular bundles is 2–6. The number of vascular bundles is more than 6, usually several. Xylem is diarch to hexarch. Xylem is polyarch.

10.

Phloem parenchyma is present.

11.

Xylem vessels are polygonal in outline.

8.

12. 13. 14.

Passage cells are present. thin

walled Pericycle becomes thick walled in older roots.

Phloem parenchyma is absent.

Xylem vessels are rounded or oval in outline. Conjunctive tissue remains thin walled Conjunctive tissues becomes thick walled and parenchymatous. and sclerified. Conjunctive tissue forms the major part Conjunctive tissue does not form any part of the vascular cambium. of the vascular cambium. Pith is small or lacking.

Pith is quite large and well developed.

Connecting Concepts  In Maize and Allium the outermost layer of the cortex possesses casparian strips on the anticlinal walls of the cells. After the shrivelling of epiblema and root hairs, the outer one (Smilax) or many (Maize) layers of the cortex become suberised and thick walled and form special layer called exodermis. In Pineapple and some grasses., sclerenchyma also develops inner to exodermis to provide extra support.

232

BIOLOGY

Fig. 6.11 Comparison of the T.S. of monocot and dicot

Main features of internal structure of stem are : • Cuticle is usually developed. •

Hairs are multicellular.

•

Vascular bundles are conjoint, collateral or bicollateral or even concentric. Further vascular bundles may be open or closed.

•

Xylem is endarch (centrifugal), i.e., protoxylem is towards pith and metaxylem towards periphery. Table : Differences between internal structure of root and stem

1.

Root Stem Outer layer is epiblema or piliferous Outer layer is epidermis and usually with layer or rhizodermis without cuticle. cuticle.

2.

Root hairs are unicellular.

3.

Chlorenchyma (parenchyma with In young stem usually chlorenchyma is present. chlorophyll) is absent in root. However, absent in mature stem.

4.

Endodermis or starch sheath is well Endodermis is usually ill developed. developed.

5.

Vascular bundles are radial.

Vascular bundles are conjoint, collateral or bicollateral or concentric.

6.

Xylem is exarch or centripetal.

Xylem is endarch or centrifugal.

Hairs are multicellular.

DICOTYLEDONOUS STEM A young stem of sunflower exhibits typical features of a dicotyledonous plant. Internally, it is differentiated into the following parts :  Epidermis: It is single layered and consists of thin-walled parenchyma cells. The cells are flattened and lack intercellular spaces. Epidermis produces a number of multicellular hairs. There is a thick cuticle above the epidermis that reduces loss of water from surface of stem. 

Cortex: It lies immediately below epidermis. Cortex is several layered and is differentiated into three regions: an outer hypodermis, middle cortical layers and an inner endodermis. •

Hypodermis: The hypodermis is composed of 4 or 5 layers of collenchymatous cells. They are living cells and contain chloroplasts. Hypodermis provides mechanical strength to plants, stores food and helps in photosynthesis.

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233

•









Cortical layer: Cortical layer lies between hypodermis and endodermis. It is made up of loosely arranged parenchymatous cells with intercellular spaces. Inside cortex number of oil ducts are present which are surrounded by protoplasmic glandular cells. Main functions of cortical layers are storage of food and carry out photosynthesis. • Endodermis: It is innermost layer of cortex that separates the vascular tissue from cortical cell. It is a single layer of barrel-shaped cells which have conspicuous casparian strips. The cells of the endodermis are rich in starch grains and the layer is also referred to as the starch sheath. Pericycle : It lies between the cortex and the vascular tissue. It is made up of both sclerenchymatous and parenchymatous cells. It is homogeneous and sclerenchymatous in Cucurbita. Sclerenchymatous cell forms a semilunar patches and placed above the phloem. Sclerenchymatous cells provide mechanical support and parenchymatous cells store food. Vascular bundles : The vascular bundles of dicotyledonous stems are always arranged in the form of a ring. They are conjoint and open. The structure of the phloem and the xylem is typical. The larger metaxylem is on the outer side and the smaller protoxylem elements Connecting Concepts to the inner side i.e. the development of the xylem is centrifugal (endarch).  In sunflower stem, sclerenchymatous Primary medullary rays : The ground tissue found in between the vascular bundles is patches of pericycle present outside the called medullary ray. It is madeup of parenchymatous cells and involved in radial conduction vascular bundle known as bundle caps. of food and water. Pith or medulla: Pith is the ground tissue present in the centre. It is made up of large parenchymatous cells with intercellular spaces. Its main function is storage of food.

Connecting Concepts  In some dicot stems, scattered vascular bundles are present (instead of in a ring). e.g., in Pepromea, Piper, Piper Thallictrum, Anemone, Nymphaea, etc.

Fig. 6.12 (a) Diagrammatic representation of T.S. of sunflower stem (b) Detailed structure of a portion of T.S. of sunflower stem

MONOCOTYLEDONOUS STEM The monocotyledonous stems are characterized by lack of differentiation of the ground tissue into cortex, pericycle, pith and by presence of the scattered vascular bundles. The details of its anatomy are as follows : 

Epidermis : It is a single layer of thin-walled parenchyma cells. A thick cuticle is present on the outer surface of epidermis.



Hypodermis : The hypodermis consists of two or three layers of thick-walled sclerenchyma cells.



Ground tissue : The entire mass of parenchymatous tissue within the hypodermis is called the ground tissue which consists of thin-walled spherical cells. The cells enclose large intercellular spaces.

 In root, there is radial arrangement of xylem and phloem strands and further xylem in root is exarch (i.e., protoxylem towards periphery). In stem, vascular bundles are conjoint and collateral and xylem is endarch (i.e., protoxylem towards centre). Inspite of these differences in arrangement, vascular continuity is maintained between root and shoot. The change from exarch condition of xylem in root to endarch condition in stem occurs in a specific region of axis, called transition zone or transition region. It is generally hypocotyl region (at base, near its middle or in upper part) in which this change or transition occurs.

234

BIOLOGY Vascular bundles : They are scattered all over in the ground tissue. Vascular bundle is surrounded by sclerenchymatous bundle sheath. Vascular bundles are collateral and closed. Peripheral vascular bundles are generally smaller than the centrally located ones. The phloem parenchyma is absent. The xylem consists of tracheids and four large vessels which are arrange in the form of the letter Y . Examples are Oxalis, Marsilea, grasses, etc. Cuticle Epidermis Sclerenchyma Cuticle

Parenchyma

(a)

Bundle sheath Protophloem Metaphloem Metaxylem Protoxylem Lysigenous cavity

Ground tissue

Vascular bundle

Epidermis Hypodermis Vascular bundles

Gr ound tissue



(b) Fig. 6.13 (a) Diagrammatic representation of T.S. of maize stem (b) Detailed structure of a portion of T.S. of maize stem

Differences between internal structure of monocot stem and dicot stem Monocot stem 1. Epidermis with comparatively smaller cells. 2. Hairs are generally absent 3. Hypodermis is sclerenchymatous. 4. Cortex is generally absent, but from hypodermis to centre of stem ground tissue is present. 5. Endodermis is absent. 6. Pericycle is absent. 7. Medullary rays are absent. 8. Pith is absent. 9. Vascular bundles : (a) Scattered V. B. (b) V.B. are conjoint, collateral and closed. (c) There is difference in the size of V.B. in the centre and at periphery, i.e., V.B. in centre are larger in size and towards periphery are smaller. (d) Bundle sheath is present around vascular bundle in monocot stem. (e) Oval vascular bundles. (f) Phloem parenchyma is absent. (g) Xylem vessels are ‘Y’ or ‘V’ shaped.

Dicot stem Epidermis is made of comparatively larger cells. Multicellular hairs are present. Hypodermis is collenchymatous. Cortex is made of many layered parenchymatous cells. Endodermis is present but usually poorly developed. Pericycle is made of one or many layers of cells. Medullary rays are present between vascular bundles. Pith is present. (a) V.B. are arranged in a ring. (b) V.B. are conjoint, collateral and open. (c) V.B. are of same size.

(d) Bundle sheath is absent. (e) Wedge shaped vascular bundles. (f) Pholem parenchyma is present. (g) Xylem vessels are radial.

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235

DORSIVENTRAL (DICOTYLEDONOUS) LEAF

Connecting Concepts 

In dorsiventral leaf, above and

These are found in dicots. These are generally horizontal and sunlight falls on their upper below the largest V.B., there are present surface (ventral surface or adaxial surface). parenchymatous or collenchymatous The important anatomial features of dorsiventral leaves are :  

mass of cells which do not contain chloroplast.

Upper epidermis : It is single-layered. It is covered with a thick cuticle. It has more  stomata than the lower epidermis.

In some dicot leaves multilayered upper epidermis is present, e.g., in Mesophyll: It is differentiated into an upper palisade parenchyma and spongy Ficus, Piper, Nerium as well as Begonia. parenchyma. The cells of the palisade parenchyma are cylindrical in shape and are Cuticle is well developed on upper compactly arranged. They have chloroplasts and, therefore, photosynthesise. They also epidermis.

check transpiration. The spongy parenchyma are loosely arranged with large intercellular spaces. They also contain chloroplasts and carry out photosynthesis. 

Vascular bundle : There is one prominent vascular bundle and several small ones. The size of the vascular bundles are dependent on the size of the veins. The veins vary in thickness in the reticulate venation of the dicot leaves. It has phloem towards the lower (abaxial) side and xylem towards the upper (adaxial) side. The vascular bundle is enclosed by thick walled bundle sheath.



Lower epidermis : It is single layered and has less stomata or may be absent. Parenchyma Cuticle Upper Epidermis Palisade Parenchyma Bundle sheath Xylem Phloem Spongy parenchyma Sub-stomatal cavity Stoma Fig. 6.14 T.S. of dicot, leaf of mango

ISOBILATERAL (MONOCOTYLEDONOUS ) LEAF These are found in monocots and are generally vertical. In transverse section, following structure is seen :  Upper epidermis : It is composed of large-sized parenchyma cells. Stomata are also present in this layer. A thick cuticle is present outside the epidermis. Bulliform cells may be present in grasses. When the bulliform cells in the leaves have absorbed water and are turgid, the leaf surface is exposed. When they are flaccid due to water stress, they make the leaves curl inwards to minimise. There are also known as motor cells e.g., in Psamma, Poa, Agropyron, Amophilla. 

Mesophyll : It is composed of round, oval or cylindrical cells. There is no differentiation into palisade and spongy parenchyma.



All the cells of the mesophyll are alike.



They are loosely arranged. They have large number of chloroplasts. In sciophytes, there may be no spongy parenchyma and the entire mesophyll may consist of only palisade parenchyma.



Vascular bundles : The vascular bundles are of uniform size. Like the dorsiventral leaves, they have phloem on the lower side and xylem on the upper side.



Vascular bundles are conjoint, collateral and closed.



Lower epidermis : Like the upper epidermis, the cells of the lower epidermis are singlelayered and composed of compactly arranged parenchyma cells. Stomata are also present in the lower epidermis.

236

BIOLOGY

Check Point Fill in the blanks 1. The cambium ring of dicot stem cut off cells towards pith, mature into _________ while towards periphery mature into _________. 2. In sciophytes, there may be no _________ and entire mesophyll consists of _________. 3. Vascular bundles of isobilateral leaf are _________ , _________ and _________. 4. _________ cells of grasses check transpiration by rolling inwards. 5. The cambium of dicot stem are more active on _________ side.

Fig. 6.15 T.S. of maize leaf

Table : Differences between dicot and monocot leaf Dicot leaf

Monocot leaf

1. Dorsiventral

Isobilateral.

2. Hypostomatic

Amphistomatic.

3. Motor cells or bulliform cells are absent. Bulliform cells are present in upper epidermis. 4. Mesophyll is differentiated into palisade Mesophyll not differentiated and all cells are and spongy parenchyma. like spongy parenchyma. 5. Above and below large vascular Sclerenchymatous cells patches are present bundles, patches of parenchymatous or above and below the large vascular bundles. collenchymatous cells are present. Connecting Concepts

SECONDARY GROWTH

 Anamolous or abnormal  secondary growth in some monocot stems, e.g., in Yucca, Dracaena, Aloe, Sensiviera and Agave, etc. 

Growth of stems and roots in length due to activity of primary (apical) meristems is called as primary growth.



Secondary growth occurs due to addition of secondary tissues (secondary cortex, secondary phloem and secondary xylem) formed by the activity of vascular cambium in the stelar region inside pericycle and cork cambium in the extrastelar regions (region outside pericycle i.e., cortex).

In most dicot stems and roots, in later stage lateral meristems (vascular cambium and the cork-cambium) become active and cause increase in the thickness. This is called as secondary growth.

Secondary Growth in dicot stem 

The vascular bundles in dicot stem are conjoint, collateral and open and are arranged in a ring.



Secondary growth is initiated by vascular cambium. Initially cambium is limited only to the vascular bundles called as intra fascicular cambium (present between phloem and xylem).



The parenchymatous cells of the medullary rays lying with the fascicular cambium become meristematic and give rise to the interfascicular cambium.



The interfascicular and the fascicular cambium join with one another to form a complete cambium ring.

ANATOMY OF FLOWERING PLANTS

237

(B)

(A)

(D) Fig. 6.16 Diagrams showing the activity of cambium ring



  



The cambial ring because becomes active and begins to cut off new cells, both towards the inner and the outer sides. The cells cut off towards pith, mature into secondary xylem and the cells cut off towards periphery mature into secondary phloem. The cambium is generally more active on the inner side than on the outer. As a result, the amount of secondary xylem produced is more than secondary phloem and soon forms a compact mass. The primary and secondary phloems get gradually crushed due to the continued formation and accumulation of secondary xylem. The primary xylem however remains more or less intact, in or around the centre. At some places, the cambium forms a narrow band of parenchyma, which passes through the secondary xylem and the secondary phloem in the radial directions. These are the secondary medullary rays.

Connecting Concepts  Rhytidome. The layer of cork cambium or phellogen becomes inactive after sometimes and successive phellogen layers develop in deeper tissues and all the dead cells outside the innermost layer of cork cambium or phellogen constitute rhytidome.

 Tyloses. These are balloon-like structures which are produced due to The activity of vascular cambium fluctuates with change in climate and under the control ingrowth of adjacent xylem parenchyma cells into the lumen of xylem vessels of a series of physiological and environmental factors. through pits.

Formation of Annual Rings or Growth Rings  





The cambium is more active during spring and summer season due to more requirement of food dissolved in water, high temperature, longer duration of sunshine, etc., hence cambium forms large-sized secondary xylem elements. This type of secondary xylem is called the spring wood or early wood. During autumn and winter season, the cambium is less active and it forms smaller, thicker and narrow xylem vessels. This is called the autumn wood or late wood. The spring wood is lighter in colour and has a lower density whereas the autumn wood is darker and has a higher density. The periodical activity of the cambium, thus results in distinct growth layers or rings of secondary xylem. These are called growth rings. The growth rings of spring wood and autumn wood produced in a year constitute an annual ring.

 The age of tree can be determined by counting annual rings in oldest or basal portion of tree trunk. Calculation of age of the tree by counting annual rings is called dendrochronology.

Wood     

W Wood is cellular and contains all tissues inner to cambium i.e., xylem and pith. The secondary- xylem is much larger in amount and constitutes the main bulk of woody stems. It is without phloem. Amount of cellulose in wood is 20-50% and remaining part is lignin and hemicellulose. Maximum part of dicot wood is made up of vessels and fibres. Wood of palms and bamboos (poorman wood) has no secondary xylem. It grows by primary meristem only.

Check Point Name the cells/tissues which constitute the following (i) Phellem (ii) Phelloderm (iii) Phellogen (iv) Inter fascicular cambium (v) Bark

238

BIOLOGY 

There are two types of wood i.e., soft wood and hard wood.



The gymnospermic wood is called softwood and the angiospermic wood is called hardwood.



Hardness and softness depend on the content of xylem fibres and xylem rays in the wood.



Soft wood : It is nonporous, homoxylous gymnospermic wood rich in tracheids and xylem parenchyma, vessels and fibres are absent and resin canals are present. This wood is good for cabinet or fancy work, e.g, Deodar (Cedrus), Pine (Pinus).



Hard wood : It is porous, heteroxylous angiospermic wood rich in vessels and fibres, tracheids and xylem parenchyma are fewer, xylem rays are multiseriate and resin canals are absent. This wood is good for construction work e.g., Teak (Tectona grandis), Sal (Shorea), Shisham (Dalbergia). Hard wood is of following two types: •

•

Ring porous wood: The woods of plants in temperate (cold) region have distinct annual rings. The vessels of the spring wood elements are much larger than those of the autumn wood. This type of wood is called the ring porous. Ring porous wood is specialised and conduct more water as they are formed early during the development when need for water is great, e.g., Cassia, Dalbergia (Shisham), Quercus (oak). Diffuse porous wood: In this type of wood, all the vessels are of uniform diameter and there is only a gradual change in the size of the elements the wood. This wood is found in plants of tropical (hot) climate e.g., Acer, Betul.

Heartwood and Sapwood     

In a very old stem the secondary xylem elements in the inner part turn darker in colour and is called the heartwood or duramen. It consists of dead elements which have a deposit of gums, resins, oils, tannins in their walls and lumens. The heartwood is, therefore, very strong and durable and imparts great amount of mechanical strength to the stem. The sapwood or alburnum is the light coloured peripheral part of the secondary xylem. It consists of dead tracheids, vessels, and fibres and some living cells. The sapwood elements continue to perform the function of conducting water and solutes etc. They also give mechanical support to the stem.

growth ring

pith

Fig. 6.17 Hard wood and Sap wood

Cork Cambium • • •

In hypodermis or outer cortical cells, a layer becomes meristematic which is known as cork cambium or phellogen. This phellogen also divides off cells both on its outer side and inner side. The cells cut off on outer side are phellem or cork cells and cells cut off on inner side are phelloderm or secondary cortex.

ANATOMY OF FLOWERING PLANTS    



239

The phellem or cork cells are dead and have deposition of a fatty substance called suberin. Phellem, phellogen and phelloderm collectively constitute periderm. The function of periderm is protective (because at maturity epidermis ruptures and hence protection function is performed by periderm). Bark is the loose term and is used to define all the tissues, outside vascular cambium. Bark = periderm + cortex + pericycle + primary and secondary phloem. Bark that is formed early in the season is called early or soft bark. Towards the end of the season, late or hard bark is formed. Lenticels are some loosely arranged areas in the periderm. Lenticels are characteristics of woody stem. They help in gaseous exchange and transpiration.

SECONDARY GROWTH IN DICOT ROOTS Dicotyledonous roots like the dicotyledonous stems increase in thickness as a result of addition of secondary tissues cut off by the cambium and the cork cambium. Origin and activity of the cambium ring  The first event in secondary growth of a dicotyledonous root is the origin of the cambium.  The cells of the conductive tissue just inside the phloem and just outside the xylem become meristematic. In order to make this cambium ring circular the wavy band of cambium becomes active only in those parts which lie on the inner side of the phloem patches.  These cambium strips cut off secondary xylem elements only on the inner side as a result of which the primary phloem are gradually pushed on to the outer side.  This sort of unequal behaviour of the cambium results in the conversion of its wavy band into a circular ring of cambium.  Once the cambium assumes a circular outline it becomes uniformly meristematic and starts cutting off cells both on the inner and the outer sides.  Except in the regions of the medullary rays the inner cells get modified into secondary xylem and the outer cells into those of the secondary phloem. Origin and activity of the cork cambium  Addition of secondary tissues in the central part of the root exerts lot of pressure on the peripheral tissues which get ruptured.  A new meristem, known as cork-cambium, develops in the single-layered pericycle to replace the lost peripheral part of the root.  The cork-cambium or the phellogen is few layers in thickness and composed of thin-walled rectangular cells. It cuts off cells on both the outer and the inner sides. The cells on the outer side are modified into brown-coloured suberized cork cells and on the inner side remain thin-walled and parenchymatous. It is termed secondary cortex.  The cork and the secondary cortex are also known as phellem and phelloderm respectively. Due to activity of cork cambium, pressure builds up on the remaining layers of phellogen and ultimately these layers die and slough off.  The bark of a root is comparatively thinner. Lenticels are fewer in number. Medullary ray Formation of Cortex Periderm Primary cambium phloem Epidermis Secondary Primary phloem xylem Cambium 

Secondary xylem Primary phloem

(a)

Primary xylem

(b)

Fig. 6.18 (a)-(b). Digrams showing secondary growth in dicot root

240

BIOLOGY

EXERCISE - 1 | NCERT BASED QUESTIONS 1.

What is true about a monocot leaf? (1) Reticulate venation (2) Absence of bulliform cells (3) Mesophyll not differentiated into palisade and spongy tissues (4) Well differentiated mesophyll

2.

Which is correct about transport or conduction of substances? (1) Organic food moves up through phloem. (2) Inorganic food moves up through phloem. (3) Inorganic food moves upwardly and downwardly through xylem. (4) Organic food moves upwardly and downwardly through phloem.

3.

4.

Which is not true about sclereids? (1) These are parenchyma cells with thickened lignified walls. (2) These are elongated and flexible with tapered ends. (3) These are commonly found in the shells of nuts and in the pulp of guava, pear, etc. (4) These are also called stone cells.

Which of the following statements is true? (1) Vessels are multicellular with narrow lumen. (2) Tracheids are multicellular with narrow lumen. (3) Vessels are unicellular with wide lumen. (4) Tracheids are unicellular with wide lumen.

6.

In barley stem vascular bundles are (1) closed and scattered (2) open and in a ring (3) closed and radial (4) open and scattered

7.

Heartwood differs from sapwood in (1) presence of rays and fibres (2) absence of vessels and parenchyma (3) having dead and non conducting elements (4) being susceptible to pests and pathogens The cork cambium, cork and secondary cortex are collectively called (1) phelloderm (2) phellogen (3) periderm (4) phellem

Identified A, B and C of root apex.

root cap (1) (2) (3) (4) 10.

Vessels are found in (1) all angiosperms and some gymnosperms (2) most of angiosperms and few gymnosperms (3) all angiosperms, all gymnosperms and some pteriodophyta (4) all pteridophyta

5.

8.

9.

A – Vascular structure, B – Protoderm, C – Root cap A – Cortex, B – Endodermis, C – Root cap A – Cortex, B – Protoderm, C – Root cap A – Tunica, B – Protoderm, C – Root cap

Choose the correct option –

(1) A – Leaf primordium, B – Shoot apical meristem, C – Axillary bud (2) A – Leaf primordium, B – Shoot apical meristem, C – Apical bud (3) A – Root hair primordium, B – Root apical meristem, C – Axillary bud (4) A – Root hair primordium, B – Root apical meristem, C – Terminal bud 11.

Function of companion cells is (1) providing energy to sieve elements for active transport. (2) providing water to phloem. (3) loading of sucrose into sieve elements by passive transport. (4) loading of sucrose into sieve elements.

12.

A tissue is a group of cells which are (1) similar in origin, but dissimilar in form and function. (2) dissimilar in origin, form and function. (3) dissimilar in origin, but similar in form and function. (4) similar in origin, form and function.

ANATOMY OF FLOWERING PLANTS 13.

14.

15.

16.

17.

Root apex is subterminal because it is (1) covered by root hairs

(2) covered by root cap

(3) covered by epidermis

(4) under the soil

241 19.

Choose the correct option for A and B –

When xylem and phloem are on same radii, the vascular bundles are said to be (1) radial

(2) conjoint/collateral

(3) concentric

(4) exarch/centripetal

Apical, intercalary and lateral meristems are differentiated on the basis of (1) origin

(2) function

(3) position

(4) development

Wood is (1) primary phloem

(2) primary xylem

(3) secondary xylem

(4) secondary phloem

(1) A – Tracheid, B – Vessel (2) A – Vessel, B – Tracheid (3) A – Fibre, B – Tracheid

Trees at sea do not have annual rings because (1) soil is sandy. (2) there is climatic variation.

(4) A – Fibre, B – Sclereid 20.

Which is the correct option for A, B and C ?

(3) there is no marked climatic variation. (4) there is enough moisture in the atmosphere. 18.

Identify the types of simple tissue indicated by A, B, C and D.

(1) A – Sieve tube, B – Phloem parenchyma, C – Companion cell (2) A – Vessel, B – Phloem parenchyma, C – Companion cell (3) A – Sieve tube, B – Phloem parenchyma, C – Phloem fibre (4) A – Sieve tube, B – Companion cell, C – Phloem parenchyma 21. (1) A – Parenchyma, B – Collenchyma, C – fibre (Sclerenchyma), D – Sclereid (Sclerenchyma) (2) A – Collenchyma, B – Parenchyma, C – fibre (Sclerenchyma), D – Sclereid (Sclerenchyma) (3) A – Parenchyma, B – Collenchyma, C – Sclereid (Sclerenchyma), D – fibre (Sclerenchyma) (4) A – Collenchyma, B – Parenchyma, C – Sclereid (Sclerenchyma), D – fibre (Sclerenchyma)

Which one of the following option is true about bulliform/ motor cell ? (1) It is seen in grasses. (2) It is large-sized, thin-walled colourless, vacoulate cells on the adaxial surface. (3) It helps in rolling of leaf to minimise water loss when it is flaccid. (4) All

242 22.

BIOLOGY The given diagrams show stomatal apparatus in dicots and monocots. Which one is correct option for A, B and C?

25.

(1) (2) (3) (4)

(1) A – Epidermal cells; B – Subsidiary cells; C – Guard cells (2) A – Guard cells; B – Subsidiary cells; C – Epidermal cells (3) A – Guard cells; B – Epidermal cells; C – Guard cells (4) A – Epidermal cells; B – Subsidiary cells; C – Guard cells 23.

26.

Radial; Conjoint closed; Conjoint open Conjoint closed; Conjoint open; Radial Conjoint open; Conjoint closed; Radial Bicollateral; Concentric; Radial

Choose the correct option for T.S. of monocot root. A B

Which one of the following statement is false ? (i)

Epidermal cell has small amount of cytoplasm and a large vacuole.

C D

(ii) Waxy cuticle layer is absent in roots.

E

(iii) Root hairs are unicellular, while stem hairs / trichomes are multicellular.

F

(iv) Trichomes may be branched or unbranched, soft or stiff and prevent transpiration. (v) Guard cells are dumbell shaped in dicots and beanshaped in monocots (e.g. grass).

24.

Identify types of vascular bundles.

(1) I

(2) IV

(3) III

(4) V

Which option is true about heart wood/duramen ? (i)

It does not help in water and mineral conduction.

(ii) It is dark coloured but soft. (iii) It has tracheary elements filled with tannins, resins, gums, oil, etc. (iv) It is a peripheral part. (v) Sensitive to microbes and insects, hence least durable. (1) I, III

(2) II, III

(3) IV, V

(4) III, IV

G H I J

(1) A – Root hair, B – Epiblema, C – Cortex, D – Endodermis, E – Passage cell, F – Pericycle, G – Pith, H – Phloem, I – Metaxylem, J – Protoxylem (2) A – Root hair, B – Epiblema, C – Cortex, D – Endodermis, E – Passage cell, F – Pith, G – Pericycle, H – Metaxylem, I – Phloem, J – Protoxylem (3) A – Root hair, B – Epiblema, C – Cortex, D – Endodermis, E – Pericycle, F – Passage cell, G – Phloem, H – Pith, I – Protoxylem, J – Metaxylem (4) A – Root hair, B – Cortex, C – Epiblema, D – Pericycle, E – Endodermis, F – Pith, G – Passage cell, H – Phloem, I – Protoxylem, J – Metaxylem

ANATOMY OF FLOWERING PLANTS 27.

243

Choose the answer for dicot root in which these alphabets have been correctly matched with the parts which they indicate.

29.

Choose the correct option for T.S. of monocot stem. A B

E B

C A

D E F

D F

(1) A – Epidermis, B – Hypodermis, C – Vascular bundles, D – Phloem, E – Xylem, F – Ground tissue (2) A – Cuticle, B – Epidermis, C – Sclerenchymatous sheath, D – Sclerenchymatous hypodermis, E – Parenchymatous sheath, F – Phloem, (3) A – Cuticle, B – Epidermis, C – Sclerenchymatous hypodermis, D – Sclerenchymatous sheath, E – Parenchymatous sheath, F – Phloem, (4) A – Cuticle, B – Epidermis, C – Sclerenchymatous hypodermis, D – Sclerenchymatous sheath, E – Parenchymatous Sheath, F – Protoxylem

C

(1) A – Epiblema, B – Root hair, C – Cortex, D – Endodermis, E – Pith, F – Pericycle (2) A – Cortex, B – Pith, C – Epiblema, D – Endodermis, E – Root hair, F – Pericycle (3) A – Epiblema, B – Endodermis, C – Cortex, D – Root hair, E – Pith, F – Pericycle (4) A – Cortex, B – Epiblema, C – Pith, D – Endodermis, E – Root hair, F – Pericycle 28.

30.

Column-I Column-II A. Spring wood or I. Lighter in colour early wood B. Autumn wood or II. Density high late wood III. Density low IV. Darker in colour V. Larger number of xylem elements VI. Vessels with wider cavity VII. Lesser number of xylem elements VIII. Vessels with small cavity Which of the following combination is correct ? (1) A – II, IV, VII, VIII; B – I, III, V, VI (2) A – I, II, VII, VIII; B – III, IV, V, VI (3) A – I, III, V, VI; B – II, IV, VII, VIII (4) A – I, III, VII, VIII; B – II, IV, V, VI

31.

T.S. of dicot leaf passing through the midrib is given below, certain parts have been indicated by alphabets. Choose the correct option.

T.S. of dicot stem is given below, certain parts have been indicated by alphabets. Choose the correct option. A

B C D E F G H I (1) A – Epidermis, B – Epidermal hairs, C – Parenchyma, D – Starch Sheath, E – Hypodermis (collenchyma), F – Vascular bundle, G – Bundle cap, H – Medulla or pith, I – Medullary rays (2) A – Epidermal hairs, B – Epidermis, C – Hypodermis (collenchyma), D – Parenchyma, E – Starch sheath, F – Bundle cap, G – Vascular bundle, H – Medullary rays, I – Medulla or pith (3) A – Epidermal hairs, B – Epidermis, C – Hypodermis (collenchyma), D – Starch sheath, E – Parenchyma, F – Vascular bundle, G – Bundle cap, H – Medulla or pith, I – Medullary rays (4) A – Epidermal hairs, B – Epidermis, C – Parenchyma, D – Hypodermis (collenchyma), E – Starch sheath, F – Vascular bundle, G – Bundle cap, H – Medulla or pith, I – Medullary rays

H G F

A

B

C D E

244

BIOLOGY (1) A – Epidermis, B – Spongy parenchyma, C – Palisade parenchyma, D – Stomata, E – Guard cells, F – Phloem, G – Metaxylem, H – Protoxylem

(1) A – Phellem, B – Phellogen, C – Medullary rays, D – Secondary xylem, E – Secondary phloem, F – Cambium ring (2) A – Phellem, B – Phellogen, C – Medullary rays, D – Secondary phloem, E – Secondary xylem, F – Cambium ring (3) A – Phellogen, B – Phellem, C – Medullary rays, D – Secondary xylem, E – Secondary phloem, F – Cambium ring (4) A – Phellem, B – Phellogen, C – Cambium ring, D – Secondary xylem, E – Secondary phloem, F – Medullary rays

(2) A – Epidermis, B – Palisade parenchyma, C – Spongy parenchyma, D – Sub-stomatal cavity, E – Stoma, F – Phloem, G – Metaxylem, H – Bundle sheath (3) A – Epidermis, B – Palisade parenchyma, C – Spongy parenchyma, D – Stomata, E – Guard cells, F – Epidermis, G – Xylem, H – Phloem (4) A – Epidermis, C – Palisade parenchyma, C – Spongy parenchyma, D – Stomata, E – Guard cells, F – Phloem, G – Metaxylem, H – Protoxylem 32.

T.S. of monocot leaf is given below, certain parts have been indicated by alphabets. Which one is the correct option?

34.

Which one of the followings option is correct for a lenticel? A

A

B

B

C

C D

D E G

F

E

(1) A – Adaxial epidermis, B – Xylem, C – Mesophyll, D – Sub-stomatal cavity, E – Abaxial epidermis, F – Phloem, G – Stoma

(1) A – Pore, B – Secondary cortex, C – Cork cambium, D – Cork, E – Complimentary cells (2) A – Pore, B – Cork cambium, C – Secondary cortex, D – Cork, E – Complimentary cells (3) A – Pore, B – Cork, C – Complimentary cells, D – Cork cambium, E – Secondary cortex (4) A – Pore, B – Complimentary cells, C – Cork, D – Cork cambium, E – Secondary cortex

(2) A – Adaxial epidermis, B – Abaxial epidermis, C – Xylem, D – Sub-stomatal cavity, E – Stoma F – Mesophyll, G – Phloem (3) A – Adaxial epidermis, B – Phloem, C – Mesophyll, D – Sub-stomatal cavity, E – Abaxial epidermis, F – Xylem, G – Stoma (4) A – Adaxial epidermis, B – Xylem, C – Stoma, D – Sub-stomatal cavity, E – Abaxial epidermis, F – Phloem, G – Mesophyll 33.

35.

Which one is correct option for old typical dicot root?

Choose the correct answer for A to F. A B

C

D E F

(1) A – Primary phloem, B – Vascular cambium, C – Secondary phloem, D – Primary xylem (2) A – Secondary phloem, B – Vascular cambium, C – Primary phloem, D – Primary xylem (3) A – Primary phloem, B – Primary xylem, C – Secondary phloem, D – Vascular cambium (4) A – Secondary phloem, B – Primary xylem, C – Primary phloem, D – Vascular cambium

ANATOMY OF FLOWERING PLANTS

245

EXERCISE - 2 | Window to Competitive Exams 1.

Branches of botany dealing with the internal organization of plants known as [CBSE'97] (1) physiology (2) ecology (3) anatomy (4) cytology

2.

The protective tissue in the plant body consists of [CBSE'97] (1) xylem, phloem and cambium (2) epidermis, cork and bark (3) sclerenchyma, prosenchyma and collenchyma (4) All of the above

3.

At maturity which of the following is enucleate? [CBSE'97] (1) Sieve cell (2) Companion cell (3) Palisade cell (4) Cortical cell

4.

5.

A leaf primordium grows into the adult leaf lamina by means of [CBSE'98] (1) apical meristem (2) lateral meristem (3) marginal meristems (4) at first by apical meristem and later largely by marginal meristems Bamboo and grasses elongate by the activity of (1) apical meristems [CBSE'98] (2) lateral meristems (3) secondary meristems (4) intercalary meristems

6.

Maximum growth in root occurs (1) at its tip (2) towards light (3) behind the apex (4) towards apex

7.

Collenchyma differs from sclerenchyma in (1) having sclereids (2) having thick walls (3) having inside lumen (4) retaining protoplasm at maturity

8.

9.

10.

11.

What happens during vascularization in plants? [CBSE'2000] (1) Differentiation of procambium is immediately followed by the development of secondary xylem and phloem. (2) Differentiation of procambium followed by the development of xylem and phloem. (3) Differentiation of procambium , xylem and phloem occurs simultaneously. (4) Differentiation of procambium followed by the development of primary phloem and then by primary xylem.

12.

Cambium of root is an example of [CBSE'2000] (1) apical meristem (2) intercalary meristem (3) primary meristem (4) secondary meristem

13.

Loading of phloem is related to [CBSE'01] (1) increase of sugar in phloem (2) elongation of phloem cell (3) separation of phloem parenchyma (4) strengthening of phloem fibre

14.

Porous wood contains (1) vessels (3) fibres

15.

Meristem helps in (1) absorption of water (2) growth of plants (1) absorption of minerals (4) transpiration

16.

Xylem in angiosperms consists of how many types of elements? [CBSE'02] (1) 4 (2) 3 (3) 2 (4) 1

17.

Axillary bud and terminal bud are derived from the activity of [CBSE'02] (1) lateral meristem (2) intercalary meristem (3) apical meristem (4) parenchyma

18.

Main function of lenticel is (1) transpiration (2) (3) gaseous exchange (4)

19.

Four radial vascular bundles are found in [CBSE'02] (1) dicot root (2) monocot root (3) dicot stem (4) monocot stem

[CBSE'98]

[CBSE'98]

Which of the following meristems is responsible for extrastelar secondary growth in dicotyledonous stem? (1) Intrafascicular cambium [CBSE'98] (2) Interfascicular cambium (3) Intercalary meristem (4) Phellogen Transition of radial vascular bundle in root to conjoint vascular bundle in stem occurs in which zone? [CBSE'99] (1) Epicotyl (2) Hypocotyl (3) Meristem (4) At base of stem Girdling experiment cannot be performed in sugarcane because [CBSE'99] (1) vascular bundles are scattered (2) vascular bundles are in a ring (3) it is unbranched (4) it is delicate cannot withstand injury

(2) (4)

[CBSE'01] tracheids parenchyma [CBSE'02]

guttation bleeding

[CBSE'02]

20. In the monocot root, we obseve (1) suberized exodermis, polyarch xylem , pith (2) exodermis, endarch, tetrach closed bundles (3) conjoint, collateral, open, polyarch vascular bundle (4) suberized exodermis, casparian strip, passage cells, cambium

246 21.

BIOLOGY Mesophyll is usually differentiated in [CBSE'02] (1) monocot leaf (2) isobilateral leaf (3) dorsiventral leaf (4) both ‘1’ and ‘2’

22. The lacunae in vascular bundles of monocot stems are [CBSE'03] (1) metaxylem (2) mucilage canal (3) lysigenous water cavity (4) large-sized vessel 23.

The cells of the quiescent centre are characterised by [CBSE'03] (1) dividing regularly to add to tunica (2) having dense cytoplasm and prominent nuclei (3) having less cytoplasm and small nuclei (4) dividing regularly to add to the corpus

24.

The apical meristem of the root is present [CBSE'03] (1) in all the roots (2) only in radicals (3) only in tap roots (4) only in adventitious roots

25.

Chlorenchyma is known to develop in the (1) pollen tube of Pinus [CBSE'03] (2) cytoplasm of Chlorella (3) mycelium of a green mould such as Aspergillus (4) spore capsule of a moss

26.

Cambium activity is highest in (1) autumn (2) spring (3) winter (4) rain

[CBSE'03]

27.

The sugarcane plant has (1) dumb-bell shaped guard cells (2) pentamerous flowers (3) reticulate venation (4) capsular fruits

[CBSE'04]

28. Grafting is successful in dicots but not in monocots because the dicots have [CBSE'05] (1) vascular bundles arranged in a ring (2) cambium for secondary growth (3) vessels with elements arranged end to end (4) cork cambium 29.

A common structural feature of vessel elements and sieve tube elements are [CBSE'06] (1) pores on lateral walls (2) presence of p-protein (3) enucleate condition (4) thick secondary walls

30. Tyloses are [CBSE'06] (1) lactiferous channels (2) compound sieve plates (3) specialized secretory cells (4) tracheal plugs which clog the lumen of vessels or tracheids 31. Endodermis is a part of (1) pericycle (3) cortex 32.

(2) medulla (4) epidermis

(3) central region of style through which the pollen tube grows towards the ovary (4) endodermis of roots facilitating rapid transport of water from cortex to pericycle 33. At maturity which of the following is non-nucleated? [CBSE'08] (1) sieve cell (2) companion cell (3) palisade cell (4) cortical cell 34. The lenticel may show the deposition of (1) cutin (2) pectin (3) lignin (4) suberin 35.

Vascular tissues in flowering plants develop from: (1) phellogen (2) plerome [CBSE'08] (3) periblem (4) dermatogen

36.

Which one of the following is resistant to enzyme action? (1) Cork (2) Wood fibre [CBSE'08] (3) Pollen exine (4) Leaf cuticle

37.

Palisade parenchyma is absent in leaves of (1) mustard (2) soyabean [CBSE'09] (3) gram (4) sorghum

38.

The annular and spirally thickened conducting elements generally develop in the protoxylem when the root or stem is [CBSE'09] (1) elongating (2) widening (3) differentiating (4) maturing

39.

One of the primary function of the ground tissue in a plant is [CBSE'09] (1) photosynthesis (2) to protect the plant (3) to anchor the plant (4) water and sugar conduction

40. Gaseous exchange between air and internal tissues of old stem takes place through [CBSE'09] (1) pits (2) stomata (3) lenticels (4) sieve plates 41.

Duramen is (1) bark (3) sap wood

42.

Anatomically fairly old dicotyledonous root is distinguished from the dicotyledonous stem by [CBSE PMT 2009] (1) absence of secondary phloem (2) presence of cortex (3) position of protoxylem (4) absence of secondary xylem

43.

The annular and spirally thickened conducting elements generally develop in the protoxylem when the root or stem is: [CBSE PMT 2009] (1) elongating (2) widening (3) differentiating (4) maturing

44.

Palisade parenchyma is absent in leaves of: [CBSE PMT 2009] (1) mustard (2) soybean (3) gram (4) sorghum

[CBSE'06]

Passage cells are thin walled cells found in [CBSE'07] (1) phloem elements that serve as entry points for substance to transport to other plant parts (2) testa of seeds to enable emergence of growing embryonic axis during seed germination

[CBSE'08]

(2) periderm (4) heart wood

[CBSE'9]

ANATOMY OF FLOWERING PLANTS 45.

In barley stem vascular bundles are: [CBSE PMT 2009] (1) closed and scattered (2) open and in a ring (3) closed and radial (4) open and scattered

46.

Reduction in vascular tissue, mechanical tissue and cuticle is characteristic of: [CBSE PMT 2009] (1) mesophytes (2) epiphytes (3) hydrophytes (4) xerophytes

47.

Alburnum is otherwise known as [Kerala PMT 2009] (1) periderm (2) sapwood (3) heart wood (4) bark (5) cork cambium

48.

At maturity the sieve plates become impregnated with [Kerala PMT 2009] (1) cellulose (2) pectin (3) suberin (4) lignin (5) callose

49.

50.

51.

52.

53.

Consider the following statements and choose the correct option. [Kerala PMT 2009] (1) The thread-like cytoplasmic strands, running from one cell to other is known as plasmodesmata. (2) Xylem and phloem constitute the vascular bundle of the stem. (3) The first form xylem elements are described as metaxylem. (4) Radial vascular bundles are mainly found in the leaves. (1) (1) is true, but (2), (3) and (4) are wrong (2) (2) is true, but (1), (3) and (4) are wrong (3) (3) is true, but (1), (2) and (4) are wrong (4) (4) is true, but (1), (2) and (3) are wrong (5) (1) and (2) are true, but (3) and (4) are wrong Which of the following is not a part of epidermal tissue system? [Kerala PMT 2010] (1) Companion cells (2) Trichomes (3) Root hair (4) Guard cells (5) Subsidiary cells Which of the following statements is true? [Kerala PMT 2010] (1) The collenchyma occurs in layers below the epidermis in monocotyledonous plants (2) Sclerenchyma cells are usually dead and without protoplasts (3) Xylem parenchyma cells are living and thin walled and their cell walls are made up of lignin (4) The companion cells are specialized sclerenchymatous cells (5) Phloem fibres are generally present in the primary phloem In woody trees, the exchange of gases between the outer atmosphere and the internal tissue of the stem takes place through [Kerala PMT 2010] (1) aerenchyma (2) stomata (3) pneumatophores (4) lenticels (5) trichomes The chief water conducting elements of xylem in gymnosperms are: [CBSE PMT 2010] (1) vessels (2) fibres (3) transfusion tissue (4) tracheids

247 54.

Which one of the following is not a lateral meristem? [CBSE PMT 2010] (1) Intrafascicular cambium (2) Interfascicular cambium (3) Phellogen (4) Intercalary meristem

55.

Heartwood differs from sapwood in: [CBSE PMT 2010] (1) presence of rays and fibres (2) absence of vessels and parenchyma (3) having dead and non -conducting elements (4) being susceptible to pests and pathogens

56. The cork of commerce comes from [CBSE'10] (1) Quercus suber (2) Quercus incana (3) Quercus ithaburensis (4) All of these 57.

Diffuse porous wood are characteristic of plants growing in [CBSE'10] (1) tropics (2) alpine region (3) temperate climate (4) cold winter regions

58.

The chief water conducting elements of xylem in gymnosperms are [CBSE'10] (1) vessels (2) fibres (3) transfusion tissue (4) tracheids

59.

Which one of the following is not a lateral meristem? (1) Intrafascicular cambium [CBSE'10] (2) Interfascicular cambium (3) Phellogen (4) Intercalary meristem

60.

Grittiness of fruit in pears is due to (1) presence of Silica (2) presence of stone cells / sclereids (3) presence of raphids (4) formation of cystolith

61.

Ground tissue includes [CBSE'11] (1) all tissues external to endodermis (2) all tissues except epidermis and vascular bundles (3) epidermis and cortex (4) all tissues internal to endodermis

62.

In land plants, the guard cells differ from other epidermal cells in having [CBSE'11] (1) cytoskeleton (2) mitochondria (3) endoplasmic reticulum (4) chloroplasts

63.

Some vascular bundles are described as open because these [CBSE'11M] (1) are surrounded by pericycle but not endodermis. (2) are capable of producing secondary xylem and phloem. (3) possess conjunctive tissue between xylem and phloem. (4) are not surrounded by pericycle.

64.

A vascular bundle in which the protoxylem is pointing to the periphery is called [CBSE'98, 11] (1) endarch (2) exarch (3) radial (4) closed

65.

Which of the following bast fibres is of great commercial value? [CBSE'11] (1) Jute (2) Flax (3) Hemp (4) All of these

[CBSE'10]

248

BIOLOGY

66.

Abnormal secondary growth is observed in (1) Dracaena (2) wheat (3) ginger (4) rice

[CBSE'11]

67.

Ground tissue includes [CBSE PMT 2011] (1) all tissues external to endodermis (2) all tissues except epidermis and vascular bundles (3) epidermis and cortex (4) all tissues internal to endodermis

68.

In land plants, the guard cells differ from other epidermal cells in having : [CBSE PMT 2011] (1) cytoskeleton (2) mitochondria (3) endoplasmic reticulum (4) chloroplasts

69.

The cork cambium, cork and secondary cortex are collectively called [CBSE PMT 2011] (1) phelloderm (2) phellogen (3) periderm (4) phellem

70.

71.

72.

73.

74.

75.

Which one of the following is wrongly matched? [CBSE PMT 2011] (1) Root pressure - Guttation (2) Puccinia - Smut (3) Root - Exarch protoxylem (4) Cassia - Imbricate aestivation Function of companion cells is [CBSE PMT 2011M] (1) providing energy to sieve elements for active transport (2) providing water to phloem (3) loading of sucrose into sieve elements by passive transport (4) loading of sucrose into sieve elements Some vascular bundles are described as open because these [CBSE PMT 2011M] (1) are surrounded by pericycle but not endodermis (2) are capable of producing secondary xylem and phloem (3) possess conjunctive tissue between xylem and phloem (4) are not surrounded by pericycle In Kranz anatomy, the bundle sheath cells have [CBSE PMT 2011M] (1) thin walls, many intercellular spaces and no chloroplasts (2) thick walls, no intercellular spaces and large number of chloroplasts (3) thin walls, no intercellular spaces and several chloroplasts (4) thick walls, many intercellular spaces and few chloroplasts Grafting experiments are not possible in monocotyledonous plants because they [AFMC 2011] (1) have conjoint vascular bundles (2) have less number of vascular bundles (3) have scattered vascular bundles (4) lack cambium cells in the vascular bundles Monocot leaves possess [AFMC 2011] (1) Intercalary meristem (2) Lateral meristem (3) Apical meristem (4) Mass meristem

76.

The term ‘bark’ refers to [JIPMER-2011] (1) phellem, phelloderm and vascular cambium (2) periderm and secondary xylem (3) cork cambium and cork (4) phellogen, phellem, phelloderm and secondary phloem

77.

The quiescent centre in root meristem serves as a [JIPMER-2011] (1) site for storage of food, which is utilised during maturation (2) reservoir of growth hormones (3) reserve for replenishment of damaged cells of the meristem (4) region for absorption of water

78.

In the sieve elements, which one of the following is the most likely function of P- proteins? [JIPMER-2011] (1) Deposition of callose on sieve plates (2) Providing energy for active translocation (3) Autolytic enzymes (4) Sealing off mechanism on wounding

79.

In dicotyledonous roots, the initiation of lateral roots takes place in [Kerala PMT 2011] (1) endodermal cells (2) cortical cells (3) epidermal cells (4) procambial cells (5) pericycle cells.

80.

In grasses, certain adaxial epidermal cells along the veins modify themselves into large empty, colourless cells called [Kerala PMT 2011] (1) bulliform cells (2) companion cells (3) guard cells (4) subsidiary cells (5) albuminous cells

81.

Meristematic tissue in vascular bundle is [JIPMER-2012] (1) phellem (2) procambium (3) interfascicular cambium (4) fascicular cambium

82.

Vessels and companion cells are found in [JIPMER-2012] (1) angiosperm (2) pteridophytes (3) bryophytes (4) thallophytes

83.

The common bottle cork is a product of : [CBSE PMT 2012] (1) Dermatogen (2) Phellogen (3) Xylem (4) Vascular Cambium

84.

Companion cells are closely associated with : [CBSE PMT 2012] (1) Sieve elements (2) Vessel elements (3) Trichomes (4) Guard cells

85.

Closed vascular bundles lack [CBSE PMT 2012] (1) Ground tissue (2) Conjunctive tissue (3) Cambium (4) Pith

86.

Water containing cavities in vascular bundles are found in [CBSE PMT 2012] (1) Sunflower (2) Maize (3) Cycas (4) Pinus

ANATOMY OF FLOWERING PLANTS 87.

Gymnosperms are also called soft wood spermatophytes because they lack : [CBSE PMT 2012] (1) Cambium (2) Phloem fibres (3) Thick-walled tracheids (4) Xylem fibres

88.

As compared to a dicot root, a monocot root has [CBSE PMT 2012M] (1) many xylem bundles. (2) relatively thicker periderm. (3) inconspicuous annual rings. (4) more abundant secondary xylem.

89.

The common bottle cork is a product of : [CBSE'2012] (1) Dermatogen (2) Phellogen (3) Xylem (4) Vascular Cambium

90.

Companion cells are closely associated with : [CBSE'2012] (1) Sieve elements (2) Vessel elements (3) Trichomes (4) Guard cells

91.

Closed vascular bundles lack [CBSE'2012] (1) Ground tissue (2) conjunctive tissue (3) Cambium (4) Pith

92.

Water containing cavities in vascular bundles are found in: [CBSE'2012] (1) Sunflower (2) Maize (3) Cycas (4) Pinus

93.

Gymnosperms are also called soft wood spermatophytes because they lack : [CBSE'2012] (1) Cambium (2) Phloem fibres (3) Thick-walled tracheids (4) Xylem fibres

94. As compared to a dicot root, a monocot root has (1) many xylem bundles. [CBSE'2012M] (2) relatively thicker periderm. (3) inconspicuous annual rings. (4) more abundant secondary xylem. 95.

Assertion : Thick cuticle is mostly present in disease resistant plants. Reason : Disease causing agents cannot grow on cuticle and cannot invade the cuticle. [AIIMS 2012] (1) If both Assertion and Reason are correct and Reason is the correct explanation of Assertion. (2) If both Assertion and Reason are correct, but Reason is not the correct explanation of Assertion. (3) If Assertion is correct but Reason is incorrect. (4) If Assertion is incorrect but Reason is correct.

96.

Age of a tree can be estimated by : (1) biomass [AIPMT (NEET) 2013] (2) number of annual rings (3) diameter of its heartwood (4) its height and girth

97.

Lenticels are involved in : (1) Gaseous exchange (3) Photosynthesis

98.

Interfascicular cambium develops from the cells of : [AIPMT (NEET) 2013] (1) Xylem parenchyma (2) Endomermis (3) Pericycle (4) Medullary rays

[AIPMT (NEET) 2013] (2) Food transport (4) Transpiration

249 99.

Which of the following statements is not true for stomatal apparatus? [NEET Kar. 2013] (1) Inner walls of guard cells are thick (2) Guard cells invariably possess chloroplasts and mitochondria (3) Guard cells are always surrounded by subsidiary cells (4) Stomata are involved in gaseous exchange

100. Meristematic tissue responsible for increase in girth of tree trunk is [NEET Kar. 2013] (1) Apical meristem (2) Intercalary meristem (3) Lateral meristem (4) Phellogen 101. Which of the following statement(s) is/are true? [AIIMS 2013] (A) Uneven thickening of cell wall is characteristic of sclerenchyma. (B) Periblem forms cortex of the stem and the root. (C) Tracheids are the chief water transporting elements in gymnosperms. (D) Companion cell is devoid of nucleus at maturity. (E) The Commercial cork is obtained from Quercus suber. (1) A and D only (2) B and E only (3) C and D only

(4) B, C and E only

102. Assertion : In stem, pericycle take active part in secondary growth. Reason : In dicots, pericycle has the capacity to produce lateral roots. [AIIMS 2013] (1) If both Assertion and Reason are correct and Reason is the correct explanation of Assertion. (2) If both Assertion and Reason are correct, but Reason is not the correct explanation of Assertion. (3) If Assertion is correct but Reason is incorrect. (4) If Assertion is incorrect but Reason is correct. 103. In one tissue, the cells are isodiametric, walls are thin and made up of cellulose and the other consists of long, narrow cells with thick and lignified cell walls. They are [Kerala PMT 2013] (1) Parenchyma and sclerenchyma (2) Parenchyma and sclerenchyma (3) Sclerenmchyma and collenchyma (4) Collenchyma and parenchyma (5) Sclerenchyma and parenchyma 104. Match Column I with Column option. Column I (A) Bulliform cells 1. (B) Pericycle 2. (C) Endarch xylem 3. (D) Exarch xylem 4. (E) Bundle sheath cells 5. (1) A-3, B-5, C-4, D-1, E-2 (2) A-2, B-5, C-1, D-3, E-4 (3) A-2, B-4, C-1, D-3, E-5 (4) A-3, B-1, C-5, D-2, E-4 (5) A-5, B-4, C-2, D-1, E-3

II and choose the correct [Kerala PMT 2013] Column II Initiation of lateral roots Root Grasses Dicot leaf Stem

250

BIOLOGY

105. Consider the following statements. [Kerala PMT 2013] (A) Xylem transports water and minerals. (B) Gymosperms lack sieve tubes and companion cells in phloem. (C) The first formed primary xylem is called metaxylem. (D) Phloem fibres (bast fibres) are made up of collenchymatious cells. Of the above statements (1) (A) and (C) alone are correct (2) (A) and (B) alone are correct (3) (C) and (D) alone are correct (4) (A) and (D) alone are correct (5) (B) and (C) alone are correct 106. The term bark refers to [Kerala PMT 2013] (1) Primary and secondary phloem only. (2) Periderm, secondary phloem and vascular cambium only. (3) Secondary xylem and cambium only. (4) Periderm only. (5) Periderm and secondary phloem only. 107. You are given a fairly old piece of dicot stem and a dicot root. Which of the following anatomical structures will you use to distinguish between the two?[AIPMT - 2014] (1) Secondary xylem (2) Secondary phloem (3) Protoxylem (4) Cortical cells 108. Tracheids differ from other tracheary elements in: [AIPMT - 2014] (1) having casparian strips (2) being imperforate (3) lacking nucleus (4) being lignified 109. Transmission tissue is characteristic feature of : [AIPMT 2015] (1) Solid style (2) Dry stigma (3) Wet stigma (4) Hollow style 110. A major characteristic of the monocot root is the presence of : [AIPMT 2015] (1) Scattered vascular bundles (2) Vasculature without cambium (3) Cambium sandwiched between phloem and xylem along the radius (4) Open vascular bundles 111. In a ring girdled plant: (1) The root dies first (2) The shoot and root die together (3) Neither root nor shoot will die (4) The shoot dies first

[AIPMT 2015]

112. Vascular bundles in monocotyledons are considered closed because: [AIPMT 2015] (1) Cambium is absent (2) There are no vessels with perforations (3) Xylem is surrounded all around by phloem (4) A bundle sheath surrounds each bundle 113. Read the different components from (1) to (4) in the list given below and tell the correct order of the components with reference to their arrangement from outer side to inner side in a woody dicot stem. (A) Secondary cortex (B) Wood (C) Secondary phloem (D) Phellem The correct order is: (1) (A), (B), (D), (C) (2) (D), (A), (C), (B) (3) (D), (C), (A), (B) (4) (C), (D), (B), (A) 114. No vessels are found in the wood of: (1) Pine (2) Eucalyptus (3) Teak (4) Shesham

[AMU’s 2015]

115. The increase in length of petiole results from the division of : [AMU’s 2015] (1) Apical meristem (2) Laterial meristem (3) Intercalary meristem (4) Phellogen 116. Age of a tree can be estimated by (1) Biomass (2) Number of annual rings (3) Diameter of its heartwood (4) Its height and girth.

[UPC PMT 2015]

117. Lenticels are involved in (1) Gaseous exchange (2) Food Transport (3) Photosynthesis (4) Transpiration

[UPC PMT 2015]

118. Bicollatcral vascular bundles occur in which of the following families? [UPC PMT 2015] (1) Cruciferae (2) Cactaceae (3) Solanaceae (4) Gramineae 119. Which of the following genera shows vessels in xylem? (1) Gnetum (2) Cycas (3) Pimus (4) Marsilea

ANATOMY OF FLOWERING PLANTS

251

EXERCISE - 3 | Test Yourself 1.

2.

3.

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Which of the following statement(s) is/are true ? (A) Uneven thickening of cell wall is characteristic of sclerenchyma. (B) Periblem forms cortex of the stem and the root. (C) Tracheids are the chief water transporting elements in gymnosperms. (D) Companion cell is devoid of nucleus at maturity. (E) The Commercial cork is obtained from Quercus suber. (1) A and D only (2) B and E only (3) C and D only (4) B, C and E only Match the followings and choose the right combination A. Endodermis i. Companion cells B. Stomata ii. Lenticels C. Sieve tube iii. Palisade cells D. Periderm iv. Passage cells E. Mesophyll v. Accessory cells (1) A–iv, B–v, C–ii, D–i, E–iii (2) A–v, B–iii, C–i, D–ii, E–iv (3) A–iv, B–v, C–i, D–ii, E–iii (4) A–ii, B–v, C–iii, D–iv, E–i Which one of the following is the earliest event towards a good graft? (1) Production of plasmodesmata in the cells at the interface of stock and scion. (2) Coordinated differentiation of vascular tissue between the stock and scion. (3) Regeneration of cortex and epidermis over the union of stock and scion. (4) Production of callus tissue between the cells of stock and scion. The quiescent centre in root meristem serves as a (1) site for storage of food, which is utilized during maturation. (2) reservoir of growth hormones. (3) reserve for replenishment of damaged cells of the meristem. (4) region for absorption of water. If there is more than one tunica layer in a stem apex, which among the following is most likely to happen? (1) All the layers will develop into epidermal cells. (2) Only the outer layer will develop into epidermal cells. (3) All the layers will develop into cortex. (4) Inner layer develops into cortex. Match the followings and choose the correct option. A. Meristem i. Photosynthesis, storage B. Parenchyma ii. Mechanical support C. Collenchyma iii. Actively dividing cells D. Sclerenchyma iv. Stomata E. Epidermal tissue v. Sclereids

7.

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(1) A–i, B–iii, C–v, D–ii, E–iv (2) A–iii, B–i, C–ii, D–v, E–iv (3) A–ii, B–iv, C–v, D–i, E–iii (4) A–v, B–iv, C–iii, D–ii, E–i Cells of tissue are living, show angular wall thickening and provide mechanical support. The tissue is (1) xylem (2) sclerenchyma (3) collenchyma (4) epidermis How many shoot apical meritsems are likely to be present in a twig of a plant possessing, 4 branches and 26 leaves? (1) 26 (2) 1 (3) 5 (4) 30 A plant tissue when stained showed the presence of hemicellulose and pectin in cells wall of its cells. The tissue is (1) collenchyma (2) sclerenchyma (3) xylem (4) meristem Which one of the following cell types always divides by anticlinal cell division? (1) Fusiform initial cells (2) Root cap (3) Protoderm (4) Phellogen Which of the following is not true difference between a stem and a root? (1) The largest xylem vessel lies towards outside in stem and inside in root. (2) The xylem and phloem tissues are arranged on the same radii in stem while they alternate in root. (3) Pith is widest tissue in dicot root and cortex is widest in dicot stem. (4) None of the above The axillary buds arise (1) endogenously from the pericyle (2) exogenously from the tissues of the main growing point (3) endogenously from the cambial tissues (4) exogenously from the innermost cortex The angiosperms have (1) tracheae and sieve tubes (2) tracheids, tracheae and sieve tubes (3) tracheae, sieve cells and sieve tubes (4) tracheids, tracheae and sieve cells Specialised parenchyma cells which store tannins, oils and crystals of calcium oxalate are called (1) sclereids (2) idioblasts (3) stone cells (4) conjunctive tissue

252 15.

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BIOLOGY Vessels differ from tracheids (1) in being derived from single cell (2) in having vertical rows of cells with dissolved cross walls (3) in being living (4) in the conduction of water Parenchymatous tissue is characterised by the (1) presence of uniform thickening (2) presence of thickening in the corners (3) presence of intercellular spaces (4) presence of lignified walls Tyloses thickenings are seen in (1) phloem cells (2) ray parenchyma only (3) collenchyma (4) ray parenchyma and xylem cells The xylem fibres are classified into (1) protoxylem and metaxylem (2) primary and secondary fibres (3) fibre tracheids and fibres (4) long and short fibres Lignin is the important constituent in the cell wall of (1) phloem (2) parenchyma (3) xylem (4) cambium Active division takes place in the cells of (1) xylem (2) phloem (3) cambium (4) sclerenchyma Vascular cambium of the root is an example of (1) apical meristem (2) intercalary meristem (3) secondary meristem (4) root apical meristem Tissue composed of non-parenchymatous cells and have isodiametric or irregular shape is called (1) sclereids (2) sclerenchyma fibres (3) sieve tubes (4) None of the above Laticiferous vessels instead of laticiferous cells are found in (1) Ficus (2) Calotropis (3) Poppy (4) Nerium Plant tissues, which are actively growing have water content of (1) 40 – 50% (2) 65 – 70% (3) 20 – 40% (4) 85 – 95% The calyptrogen of the root apex forms (1) rhizoids (2) root nodule (3) root hairs (4) root cap Consider the following statements and choose the correct option– (i) The thread like cytoplasmic strands, running from one cell to other is known as plasmodesmata. (ii) Xylem and phloem constitute the vascular bundle of the stem. (iii) The first form xylem elements are described as metaxylem.

27.

28.

(iv) Radial vascular bundles are mainly found in the leaves. (1) (i) is true, but (ii), (iii) and (iv) are wrong (2) (ii) is true, but (i), (iii) and (iv) are wrong (3) (iii) is true, but (i), (ii) and (iv) are wrong (4) (i) and (ii) are true, but (iii) and (iv) are wrong Match the following and choose the correct combination A. Xylem vessels i. Store food materials B. Xylem tracheids ii. Obliterated lumen C. Xylem fibre iii. Perforated plates D. Xylem parenchyma iv. Chisel-like ends (1) A–iv, B–iii, C–ii, D–i (2) A–iii, B–ii, C–i, D–iv (3) A–iii, B–iv, C–ii, D–i (4) A–i, B–ii, C–iii, D–iv The following diagrams show the types of secondary thickenings in the xylem vessels. Identify the types labelled from A to F. Choose the correct option from those given

E

A

29.

30.

31.

B

C

D

F

(1) A – spiral, B – annular, C – reticulate, D – scalariform, E – pitted with border, F – pitted, simple (2) A – annular, B – spiral, C – scalariform, D – reticulate, E – pitted with border, F – pitted, simple (3) A – annular, B – spiral, C – scalariform, D – reticulate, E – pitted, simple, F – pitted with border (4) A – spiral, B – annular, C – scalariform, D – reticulate, E – pitted with border, F – pitted, simple A transverse section of stem is stained first with safranin and then with fast green following the usual schedule of double staining for the preparation of a permanent slide. What would be the colour of the stained xylem and phloem? (1) Red and green (2) Green and red (3) Orange and yellow (4) Purple and orange Cork is impervious to water due to (1) silica in cell well (2) CaCO3 in cell wall (3) suberin in cell wall (4) cuticle in cell wall A vesselless piece of stem possessing prominent sieve tubes would belong to (1) Pinus (2) Eucalyptus (3) Grass (4) Trochodendron

ANATOMY OF FLOWERING PLANTS 32.

33.

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35. 36.

37. 38.

39. 40.

41.

In a vascular bundle, if xylem vessels develop in a centripetal fashion, the xylem is likely to be (1) mesarch (2) centrarch (3) endarch (4) exarch All the following statements regarding sieve tube elements are true except (1) their end walls have perforated sieve plates which become impregnated with lignin at maturity. (2) they possess peripheral cytoplasm as well as a large vacuole. (3) distinct proteinaceous inclusions, the P-proteins are seen evenly distributed throughout the lumen. (4) long, slender, tube-like structures arranged in longitudinal series. Presence of vessel in the wood is (1) a primitive character (2) an advance character (3) a vestigeal character (4) None of the above DNA content of quiescent zone is (1) high (2) low (3) very high (4) balanced There is no distinction between tunica and corpus layers in the stem apices of (1) some pteridophytes (2) some gymnosperms (3) all pteridophytes (4) all angiosperms The commercial jute fibres are obtained from (1) interxylary fibres (2) xylem fibers (3) phloem fibers (4) None of these The vessel elements of angiosperms differ from other elements of xylem in having (1) simple pits on their radial walls (2) bordered pits on their lateral walls (3) simple and bordered pits on their end walls (4) simple perforation on their end walls The cell wall of sclerenchyna is rich in (1) lipid (2) cellulose (3) lignin (4) Both (2) and (3) Which one of the following statements pertaining to plant structure is correct? (1) Cork have no stomata, but lenticels carry out transpiration. (2) Passage cells help in transfer of food from cortex to phloem. (3) Sieve elements possess cytoplasm but not nuclei. (4) The shoot apical meristem has a quiescent centre. Match the Column I with Column II and choose the correct combination A. Radial vascular bundle i. Cucurbita pepo B. Collateral vascular bundle ii. Dracaena C. Bicollateral vascular iii. Root of angiosperms D. Bundle E. Amphivasal vascular iv. Sunflower stem bundle v. Fern

253

42.

43.

44.

45.

46.

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48.

(1) A–iii, B–iv, C–i, D–v, E–ii (2) A–ii, B–iii, C–i, D–v, E–iv (3) A–iii, B–iv, C–v, D–i, E–ii (4) A–iv, B–v, C–i, D–ii, E–iii (5) A–iii, B–i, C–ii, D–iv, E–v A bicollateral vascular bundle has the following arrangement of tissues (1) Outer phloem – outer xylem – middle cambium – inner xylem – inner phloem (2) Outer cambium – Outer phloem – middle xylem – inner phloem – inner cambium (3) Outer phloem – Outer cambium – middle xylem – inner cambium – inner phloem (4) Outer xylem – Outer cambium – inner cambium – inner xylem Identify the correct statement (1) Because of marked climatic variations, plants growing near the sea shore do not produce annual rings. (2) The age of the plant can be determined by its height. (3) Healing of damaged tissue is because of the activity of sclerenchyma cells. (4) Grafting is difficult in monocot plants as they have scattered vascular bundles. A concentric amphivasal (leptocentric) vascular bundle is one in which (1) centrally located phloem is surrounded by the xylem or xylem surrounds phloem. (2) centrally located xylem is surrounded by phloem. (3) xylem is flanked by phloem on the interior and exterior side only. (4) phloem is flanked by the xylem on interior side only. The distinct cavities (lacunae) found in a mature vascular bundle of maize stem are formed due to (1) disruption of protoxylem as well as lysis of adjacent xylem parenchyma. (2) disruption of protoxylem alone. (3) lysis of xylem parenchyma. (4) dissolution of common wall between a few metaxylem elements and their consequent coalition. Match the following and choose the correct option A. Cuticle i. guard cells B. Bulliform cells ii. outer layer C. Stomata iii. waxy layer D. Epidermis iv. empty colourless cell (1) A–iii, B–iv, C–i, D–ii (2) A–i, B–ii, C–iii, D–iv (3) A–iii, B–ii, C–iv, D–i (4) A–iii, B–ii, C–i, D–iv Which one is a tissue system? (1) Parenchyma (2) Xylem (3) Epidermis (4) Phloem Epiblema of roots is equivalent to (1) pericycle (2) endodermis (3) epidermis (4) stele

254 49.

50.

51. 52.

53.

54.

55.

56.

BIOLOGY A conjoint and open vascular bundle will be observed in the transverse section of (1) monocot root (2) monocot stem (3) dicot root (4) dicot stem Epidermis is absent in (1) root tip and shoot tip (2) shoot bud and floral bud (3) ovule and seed (4) petiole and pedicel When we peel the skin of a potato tuber, we remove (1) periderm (2) Epidermis (3) cuticle (4) leaves Match the names of the structures listed under column-I with the functions given under column-II, choose the answer which gives the correct combination of the alphabets of the two columns : Column-I Column-II (Structure) (Function) A. Stomata (i) Protection of stem B. Bark (ii) Plant movement C. Cambium (iii) Secondary growth D. Hydathode (iv) Transpiration (v) Guttation (1) A – (v), B – (iii), C – (i), D – (iv) (2) A – (i), B – (iv), C – (v), D – (iii) (3) A – (ii), B – (iv), C – (i), D – (iii) (4) A – (iv), B – (i), C – (iii), D – (v) Which one of the following statement is true about lenticels? (1) These are made of green living cells, which can change their size. (2) These are made of non-green, living cells, which can change their size. (3) These are made of dead cells, which can change their size. (4) These are made of dead cells, which cannot change their size. Bicollateral conjoint vascular bundles have (1) xylem and phloem, which are arranged in an alternate manner on different radii. (2) xylem and phloem, which are situated at the same radius and it has two groups of phloem along the two sides of xylem (inside and outside). (3) xylem and phloem in same radius but it has only one group phloem outside the xylem. (4) phloem surrounds the xylem tissues. A stele with a central core of xylem surrounded by phloem is called (1) protostele (2) siphonostele (3) solenostele (4) dictyostele The length of different internodes in a culm of sugarcane is variable because (1) size of leaf lamina at the node below each internode (2) intercalary meristem (3) shoot apical meristem (4) position of axillary buds

57.

58.

59.

60.

61.

62.

63.

The large, empty and colourless cells present at intervals on the upper surface of grass leaf are called (1) bulliform cells (2) palisade parenchyma (3) spongy parenchyma (4) accessory cells In root, pericycle gives rise to (1) lateral root and cork cambium (2) cortex and pith (3) epidermis and vascular bundles (4) xylem and phloem Adventitious roots in a dicot stem originate from (1) radicle (2) pericycle or interfascicular parenchyma (3) cortex (4) None of these Raphides are found in (1) Citrus (2) Colocasia (3) Nerium (4) Mango Pith is absent in (1) protostele (2) siphonostele (3) solenostele (4) cladosiphonostele Choose the correct statement (s) (A) In a dicot root, the vascular bundles are collateral and endarch (B) the inner most layer of cortex in a dicot root is endodermis (C) In a dicot root, the phloem cells are separated from the xylem by parenchymatous cells known as the conjunctive tissue. Of these statements given above (1) A is true, but B and C are false (2) B is true, but A and C are false (3) A is false, but B and C are true (4) C is false, but A and C are true In the diagram of T.S. of Stele of Dicot Root, the different parts have been indicated by alphabets; choose the answer in which these alphabets correctly match with the parts they indicate

(1) A – Endodermis C – Metaxylem E – Phloem (2) A – Endodermis C – Protoxylem E – Phloem

B – Conjunctive tissue D – Protoxylem F – Pith B – Pith D – Metaxylem F – Conjunctive tissue

ANATOMY OF FLOWERING PLANTS

64.

65.

66.

67.

68.

69.

70.

(3) A – Pericycle B – Conjunctive C – Metaxylem tissue D – Protoxylem E – Phloem (4) A – Endodermis B – Conjunctive tissue C – Protoxylem D – Metaxylem E – Phloem F – Pith Which one of the following statements is correct ? (1) Ring porous vessels are specialised and are used for conducting more water for a shorter period only, when tyloses occur early in the vessels. (2) Although diffuse porous vessels are not so specialized as ring porous vessels, they conduct more water at all periods and through new xylem vessels added gradually during development. (3) Diffuse porous vessels carry more water and also faster because of a greater number of small vessels having greater capillary force. (4) Ring porous vessels conduct more water as they are formed early during development, when the need for water is great. In a dicotyledonous stem, the sequence of tissues from the outside to the inside is (1) phellem – pericycle – endodermis – phloem (2) phellem – phloem – endodermis – pericycle (3) phellem – endodermis – pericycle – phloem (4) pericycle – phellem – endodermis – phloem In the monocot root we observe (1) Conjoint, collateral, open polyarch vascular bundle (2) Exodermis, endarch, tetrarch closed vascular bundles (3) Suberized exodermis, casparian strip, passage cells, cambium (4) Suberized exodermis, polyarch xylem, pith In a vertical section of a dorsiventral leaf, the protoxylem in its midrib bundle (1) faces the dorsal epidermis of the leaf (2) faces the ventral epidermis of the leaf (3) is not distinct (4) is surrounded by metaxylem Collenchymatous hypodermis is characteristics of (1) dicot stem (2) monocot stem (3) monocot as well as dicot stem (4) hydrophytes Kranz anatomy is found in (1) monocots (2) dicots (3) both (1) and (2) (4) None of these For a critical study of secondary growth in plants, which one of the following pairs is suitable? (1) Sugarcane and sunflower (2) Teak and pine (3) Deodar and fern (4) Wheat and maiden hair fern

255 71.

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Which of the following statement(s) is/are not true? (A) Cork cambium is also called phellogen. (B) Cork is also called phellem (C) Secondary cortex is also called periderm. (D) Cork cambium, cork and secondary cortex are collectively called phelloderm. (1) C and D only (2) A and B only (3) B and C only (4) B and D only A nail is driven into the trunk of a 30 year old tree at a point 1 meter above the soil level. The tree grows in height at the rate of 0.5 meters a year. After three years, the nail will be (1) 1 metre above the soil (2) 1.5 metres above the soil (3) 2 metres above the soil (4) 2.5 metres above the soil Interfascicular cambium and cork cambium are formed due to (1) cell division (2) cell differentiation (3) cell dedifferentiation (4) redifferentiation Phellogen and phellem respectively denote (1) cork and cork cambium (2) cork cambium and cork (3) secondary cortex and cork (4) cork and secondary cortex A piece of wood having no vessels (trachea) must be belong to (1) teak (2) mango (3) pine (4) palm What is the fate of primary xylem in a dicot root showing extensive secondary growth ? (1) It is retained in the centre of the axis. (2) It gets crushed. (3) It may or may not get crushed. (4) It gets surrounded by primary phloem. Identify the correct order of components with reference to their arrangement from outer side to inner side in a woody dicot stem : I. Secondary cortex II. Autumn wood III. Secondary phloem IV. Phellem (1) II, III, I, IV (2) III, IV, II, I (3) IV, I, III, II (4) I, II, IV, III Why is cambium considered a lateral meristem? (1) Because it gives rise to lateral branches. (2) Because it causes growth in girth. (3) Because it increases height and diameter of a plant. (4) Because it adds bulk to a plant. The cross section of a trunk of tree shows 50 annual rings, the age of tree is (1) 25 years (2) 50 years (3) 100 years (4) 50 months

256 80.

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BIOLOGY A nectar secreting gland cell characteristically contains (1) granular cytoplasm filling the cell and a small nucleus (2) granular cytoplasm lining a central vacuole and a small nucleus (3) granular cytoplasm filling the cell and a large conspicuous nucleus (4) vacuolated cytoplasm but with a large nucleus Pair the species with the type of wood. Species Type of wood A. Tectona grandis I Softwood B. Cedrus deodara II Hardwood C. Shorea robusta D. Dalbergia sissoo A B C D (1) I II II I (2) I I II II (3) II I II II (4) II I I II Which one of the tissue is formed in stems from cells cut off by the cambium on its inner side? (1) Wood fibres (2) Bast fibres (3) Sieve tube (4) Companion cells After two or three years of the secondary growth, the cortex in dicot root (1) remains intact (2) is completely sloughed away (3) is largely lost (4) is converted into cork As secondary growth proceeds, in a dicot stem, the thickness of (1) sapwood increases (2) heartwood increase (3) both sapwood and heartwood increases (4) both sapwood and heartwood remains the same

85.

The trees growing in desert will (1) show alternate rings of xylem and sclerenchyma (2) have only conjunctive tissue and phloem formed by the activity of cambium (3) show distinct annual rings (4) not show distinct annual rings

86.

Removal of ring wood of tissue outside the vascular cambium from the tree trunk kills it because (1) water cannot move up (2) food does not travel down and root become starved (3) shoot become starved (4) annual rings are not produced

87.

Sap wood is converted into heart wood (1) by degeneration of protoplast of living cells (2) by formation of tylosis (3) by deposition of resins, oil, gums (4) All of the above

88.

89.

Vascular tissues in flowering plants develop from (1) periblem

(2) dermatogen

(3) phellogen

(4) plerome

Youngest layer of secondary xylem in wood of dicot stem is located just (1) outside the cambium (2) inside the cambium (3) outside pith

90.

(4) inside the cortex

Tissue(s) present in an annual ring is/ are (1) secondary xylem and phloem (2) primary xylem and phloem (3) secondary xylem only (4) primary phloem and secondary xylem

ANATOMY OF FLOWERING PLANTS

257

ANSWER KEY EXERCISE 3 : TEST YOURSELF

EXERCISE 1 : NCERT BASED QUESTIONS 1.

(3)

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New cells form a mass of parenchymatous cells

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Quiescent centre have low rate of cell division.

21.

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Because tunica shows only anticlinal division and

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(1)

EXERCISE 2 : WINDOW TO COMPETITIVE EXAMS 1.

(3)

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34.

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35.

(2)

36.

(3)

37.

(4)

38.

(4)

39.

(1)

40.

(3)

41.

(4)

42.

(3)

43.

(4)

44.

(4)

45.

(1)

46.

(3)

47.

(2)

48.

(5)

49.

(5)

50.

(1)

51.

(2)

52.

(4)

53.

(4)

54.

(4)

55.

(3)

56.

(1)

57.

(1)

58.

(4)

59.

(4)

60.

(2)

61.

(2)

62.

(4)

63.

(2)

64.

(2)

65.

(4)

66.

(1)

67.

(2)

68.

(4)

69.

(3)

70.

(2)

71.

(4)

72.

(2)

73.

(2)

74.

(4)

75.

(1)

76.

(4)

77.

(3)

78.

(4)

79.

(5)

80.

(1)

81.

(4)

82.

(1)

83.

(2)

84.

(1)

85.

(3)

86.

(2)

87.

(4)

88.

(1)

89.

(2)

90.

91.

(3)

92.

(2)

93.

(4)

94.

(1)

95.

96.

(2)

97.

(1)

98.

(4)

99.

(3)

known as callus.

its is responsible for surface growth. 6.

(2)

7.

(3)

8.

(3)

9.

(1)

10.

(4)

11.

(3)

12.

(4)

13.

(2)

14.

(2)

15.

(2)

16.

(1)

17.

(4)

A bladder like structure are formed during the secondary growth and blocks the continuity of the conducting system. It is known as tyloses which found in xylem cells and ray parenchyma.

18.

(3)

19.

(3)

20.

(3)

Cambium represents lateral meristem of plant which has actively dividing cells.

21.

(3)

22.

(1)

23.

(3)

24.

(4)

25.

(4)

26.

(4)

27.

(3)

28.

(2)

29.

(1)

30.

(3)

31.

(4)

32.

(4)

33.

(1)

34.

(2)

35.

(2)

36.

(4)

37.

(3)

Commercial jute fibres are obtained from phloem. These are sclerenchymatous because of their presence in phloem they are called phloem fibres. They are used in making ropes.

38.

(4)

39.

(4)

40.

(3)

41.

(1)

42.

(3)

(1)

43.

(4)

44.

(1)

45.

(2)

46.

(1)

47.

(3)

(1)

48.

(3)

49.

(4)

50.

(1)

51.

(1)

52.

(4)

(3)

100. (3)

53.

(3)

54.

(2)

101. (4)

102. (3)

103. (2)

104. (4)

105. (2)

106. (5)

107. (3)

108. (2)

109. (1)

110. (2)

are present on the same radius and one xylem patch

111.

(1)

112. (1)

113. (2)

114. (1)

115. (3)

is present in between the two phloem patch, e.g.,

116.

(2)

117. (1)

118. (3)

119. (1)

In bicollateral vascular bundle, xylem and phloem

Cucurbita.

258

BIOLOGY

55.

(1)

56.

(2)

57.

(1)

58.

(1)

59.

(2)

70.

(2)

71.

(1)

72.

(1)

73.

(1)

74.

(2)

60.

(3)

61.

(1)

62.

(3)

63.

(4)

64.

(4)

75.

(3)

76.

(1)

77.

(3)

78.

(2)

79.

(2)

65.

(3)

66.

(4)

67.

(1)

68.

(1)

80.

(3)

81.

(3)

82.

(1)

83.

(3)

84.

(3)

69.

(3)

Kranz type anatomy occurs in both monocot leaves

85.

(4)

The trees growing in desert will not show distinct

(e.g., Sugarcane. Maize and Sorghum etc.) and some

annual rings because climatic variations (autumn

dicot leaves (e.g., Amaranthus-edulis, Atriplex rosea

and spring seasons) are absent in deserts.

etc).

86.

(2)

87.

(4)

88.

(4)

89.

(2)

90.

(3)

Chapter

7

Animal Tissues (Histology) & Cockroach, Earthworm and Frog Part-I : Animal Tissues (Histology) While going through the chapter pay special attention to the following Terms and definitions – 1. Histology 4. Mast cells 7. Sesamoid bone 10. Nissl granules

2. 5. 8. 11.

Clasmatocytes Polycythemia Eosinophilia Glisson’s capsule

3. 6. 9. 12.

Perineurium Crenation Neurilemma Trichology

Differences – 1. Apocrine and Holocrine glands 2. Ciliated Epithelium and Brush bordered Epithelium 3. Ligaments and Tendons 4. Investing bone and Replacing bone 5. Haversian canal and Volkman’s canal 6. Sickle cell anaemia and Thalassaemia 7. Stratified and Pseudostratified Epithelium 8. Granulocytes and Agranulocytes 9. Sensory nerves and motor nerves 10. Red pulp and white pulp 11. Integument and skin Tissues– 1. Squamous Epithelium 2. 3. Transitional Epithelium 4.

Areolar tissue Fluid connective tissue 5.

Structures – 1. Sudorific glands 4. Paccinian cor corpuscles

Ruffini’s end bulbs Chromatophores

2. 5.

3.

Adipose tissue Kupffer cells

 The study of tissues is called Histology.  Founder of Histology - Marcello Malpighii.  Term ‘tissue’ was given by Bichat.  Term ‘Histology’ was given by Mayer. Tissue It is a group of similar cells (of similar embryonic origin) along with intercellular substances, which performs a specific function. 4-major types of tissue – 1. Epithelial Tissue 2. Connective Tissue 3. Nervous or Neural Tissue 4. Muscular Tissue

At a Glance  Epithelial tissue  Simple epithelium  Compound epithelium  Glands  Connective tissue  Proper connective tissue  Skeletal connective tissue  Fluid connective tissue  Nervous tissue  Muscular tissue  Organ histology  Liver  Spleen  Pancreas  Gut (alimentary canal)  Integument  Mammallian skin  Frog’s skin  Cockroach  External features  Mouth parts  Digestive system  Excretory system  Blood vascular system  Respiration  Nervous system & sensory organs  Reproductive system  Development  Earthworm  External features  Bodywall and coelom  Locomotion  Nutrition  Respiration  Excretory system  Blood vascular system  Nervous system  Reproductive system  Frog  External morphology  Internal morphology and physiology  Development and metamorphosis  Biological importance

260

BIOLOGY

1. EPITHELIAL TISSUE 

It is Ectodermal, Mesodermal or endodermal in origin.



Its cells are compactly arranged. The intercellular material (matrix) is either absent or negligible.



It covers the body surface, or lines the body cavity. One surface of the this tissue is generally free.



The cells rest upon a non-cellular basement membrane which is secreted by epithelial cells.



It is not nourished by blood, so non-vascularized.



The structures like Cilia, Flagella and Desmosomes (cell junctions) are usually associated with such tissue.



Term ‘epithelium’ was introduced by Ruysh.

.

Types of Epithelial Tissue 1. 2.

Simple Epithelium Compound Epithelium - (i) Transitional Epithelium (ii) Stratified epithelium

1. Simple Epithelium This epithelium is one-celled thick, and can be of 3-basic types (a) Squamous epithelium •

It is also called as Pavement epithelium or Tessellated epithelium.

•

The cells resemble floor - tiles. The length and breadth of the cells is more than the thickness of the cells.

Such epithelium is generally present in places where diffusion occurs. eg. Alveolar Epithelium, Inner lining of bowman’s capsule, Capillary epithelium (Endothelium), Coelomic epithelium ((Peritonium), Pleural membrane (covering of lungs) and eyelens epithelium. Cuboidal epithelium

•

(b)

The cells are cubical having similar length, breadth and height (thickness) eg. Germinal epithelium, Follicular epithelium of thyroid gland, Lining of DCT, Ascending limb (thick) of Henley and collecting tubule of kidney. Columnar epithelium

•

(c)

•

The height (thickness) of the cells is more than the length or the breadth

•

Such epithelial lining is generally glandular or secretory. eg. Lining of Acini (exocrine part) of Pancreas, lining of gall bladder, Stratum germinativum of skin and Lining of stomach and intestine.

Specialized epithelium (i)

Pseudostratified Epithelium •

Epithelium is single cell thick but appears to be double layered due to different heights of the cells, and position of nuclei in them.

• (ii)

The majority of the cells are ciliated, whereas certain cells, in between, are nonciliated. The non-ciliated cells secrete mucus. eg. Epithelium of Trachea and bronchi Sensory Epithelium -

•

These cells are innervated (have neurons) and receive various types of stimuli. eg.Retina, Schenedarian membrane (olfactory) and lining of membranous labyrinth. (iii) Brush-bordered Epithelium •

The cells contain microvilli which increase the surface area for absorption.

•

The microvilli may be short and regular (eg. Lining of Ileum and PCT ) or long and irregular (called stereocilia) - eg. Epididymis.

ANIMAL TISSUES (HISTOLOGY) & COCKROACH, EARTHWORM AND FROG

261

(iv) Ciliated Epithelium •

All surface-cells are ciliated.

•

The Cilia help in movement of sperms in Vas deferens, oviduct or fallopian tube, or in movement of mucus from trachea into Pharynx.

Simple squamous

Simple cuboidal

Pseudostratified and ciliated (columnar)

Transitional

Simple columnar

Stratified squamous (non-keratinized)

Fig. 7.1 : Types of Epithelia

2. Compound Epithelium I.

Transitional Epithelium • • •

It is 2-6 cells thick. Basement membrane is absent. It occurs in the areas where stretching is required eg. Epithelium of Urinary bladder, Ureter and Pelvis.

II. Stratified Epithelium • This epithelial layer is more than 6 cells thick.. • Basement membrane is present but single. • The name of the epithelium is according to the ‘cells’ of the top layer. (a) Stratified Squamous Epithelium • It is the most common stratified epithelium. • The cells of the top layer are squamous. • Such epithelium occurs in the region where protection is required, or where there is sufficient wear and tear of the tissue. eg. Buccal cavity (cheek epithelium), skin, pharynx, oesophagus, vaginal epithelium, urethra, conjunctiva and cornea. (b) Stratified Cuboidal Epithelium It is present in the ducts of mammary glands and sweat glands. (c) Stratified Columnar Epithelium It mainly occurs in the embryonic tissue and is poorly developed in adults.

Glands They are epithelial in origin and therefore, may develop from any of the 3-germ layers. They can be Exocrine or Endocrine type ; Unicellular (ex. Goblet glands) or multicellular type. The exocrine glands, on the basis of secretion, are of 3-types – 1. Merocrine glands • Also known as Eccrine glands. • The secretion from these glands is watery. • The secretion diffuses out of the cells without cell injury eg. Salivary glands and sweat glands.

Check Point 1. Answer the followings : (i) Who is the founder of histology? (ii) Which epithelium does not have basement membrane? (iii) What type of epithelium do the alveoli have? (iv) Which type of glands release their secretion outside the cell without any cell-injury? (v) From which germ layer/s do the exocrine glands arise? (vi) Which type of epithelium is present in buccal cavity? (vii) Which epithelium lines the oviduct? (viii) Which part of respiratory tract has pseudostratified epithelium

262

BIOLOGY

Merocrine

Apocrine

Holocrine

Fig. 7.2 : Types of Exocrine glands (illustrating mode of secretion)

2.

Apocrine glands •

The secretion in such glands accumulate in the apical part of the cells and this part is later on pinched off. Due to this the size of the cells is reduced.

These cells grow again and accumulate the secretory product eg. Mammary glands, and sweat glands of armpit and thigh pit, which produce brownish pigment with the sweat. (The mammary glands are considered to be the modification of Apocrine sweat glands.) Holocrine glands

•

3.

•

The secretion from the cells of such glands is oily.

•

The secretion comes out of the cells only after the cell - disintegration eg. Sebaceous glands.

Cell Junctions The cells of epithelial and other tissues are held together by various types of cell junctions, that can be categorized into 3- main groups (I) Adhesive junctions The cells of epithelial tissue, and even cardiac muscles are difficult to separate due to the presence of adhesive junctions. Such junctions are of 2-types (a) Adherens junctions (b) Desmosomes (a) Adherens junctions (Zonulae adherens) - Such junctions are common in epithelial living of intestine where they form a ‘belt’ encircling the apical portion of cells and binding them to surrounding cells. Such junctions are formed by calcium -dependant-linkages of cadherin (protein) molecules and cement the cells for providing a pathway for signals from cell exterior to the cytoplasm. (b) Desmosomes (Maculae adherens) - These are disc-shaped adhesive junctions found in varieties of tissues, like skin, uterine cervix and cardiac muscles, which are subjected to mechanical stress. Desmosomes also contain cadherins for binding the cells. (II) Tight junctions (Zonulae occludens) In simple /single layered epithelium the cells are adhered tightly to one another to form a thin cellular sheet. Such junctions seal the extracellular space and block the diffusion of solutes through the paracellular pathway. The adjoining membrane make contact at certain points rather than being fused over a large surface area. The tight junctions, serve as a barrier to the free diffusion of water and solutes from the extra cellular compartment on one side of an epithelial sheet to that on the other side. The tight junctions, also act as ‘fences’ to block the diffusion of integral proteins. The proteins that form the structural component of tight junctions are Claudin and Occludin. The tight junction also make the skin impermeable to water . The junction between endothelial cells of blood capillaries also form the blood brain barrier which prevents the substances from passing from blood into the brain. Such blood brain -barrier also prevents the access of many drugs to CNS. (III) Gap junctions Such junctions are specialized for intercellular communication and are composed of integral membrane protein - Connexin, forming molecular pipelines between adjacent cells. Such gap junction channels can be opened or closed like gated channels. The stimulation of cardiac or smooth muscle cells involves gap junctions. The impulse from SAN of heart also flows from one cardiac muscle cell to another through gap junctions causing the cells to contract in synchrony. The similar gap junctions are responsible for peristalsis wave in smooth muscles. The gap junctions allow the passage for ATPs / Cyclic AMP / Coenzymes / Sugars / Phosphates and amino acid etc.

ANIMAL TISSUES (HISTOLOGY) & COCKROACH, EARTHWORM AND FROG

Plasmodesmata Unlike animal cells, the plant cells are separated from one another by cell wall. Hence, plant cells lack cell adhesion molecules or specialized cell junctions found in animal cells /tissues. Most of the plant cells are, however, connected to one another by Plasmodesmata (sign - Plasmodesma) The plasmodesmata are cytoplasmic channels that pass through the cell walls of adjacent cells. They contain desmotubule derived from smooth ER of the two cells. Like gap junction between animal cells, the plasmodesmata also serve as site for cell-to-cell communication as substances pass through the annulus surrounding the desmotubule. Unlike gap-junctions, whose pipe lines have a fixed opening, the plasmodesmata pore is capable of dialation. (The plant viruses spread from one cell to another through plasmodesmata by encoding a ‘movement protein’ that interacts with the wall of plasmodesmata to increase the diameter of the pore).

II CONNECTIVE TISSUE •

It is mesodermal in origin.

•

It binds and supports body parts.

•

The cells are loosely arranged, i.e. the intercellular matrix is well developed.

•

Basement membrane is absent.

•

It is nourished with the blood / lymph. Connective Tissue

Proper connective Tissue Loose con. T.

Specialized connective Tissue

Dense con.T.

Areolar Adipose Mucons Dense con. T. con. T. con. T. Regular con. T.

Skeletal con. T.

Dense Irregular Bone con. T.

Fluid con. T.

Cartilage Blood

Lymph

1. Proper Connective Tissue A. (a)

Loose connective Tissue-

Areolar tissue •

It consists of three prominent types of cells - Fibroblast cells, Mast cells and Macrophages.

•

Mast cells secrete heparin (anticoagulant), histamine and serotonin (5-hydroxy tryptamine – 5HT). (A major amount of heparin is, however, secreted from liver.)

•

Histamine is a vasodilator and lowers B.P. It is also involved in allergic reactions.

•

Serotonin is a vasoconstrictor and increases blood pressure.

•

The macrophages. also known as Clasmatocytes, are phagocytic cells. They are modified monocytes (WB.C.)

•

The fibroblast cells produce white and yellow fibers. These cells are the largest cells of the Areolar tissue.

263

264

BIOLOGY

Fig. 7.3 : Areolar (Loose) Connective Tissue

1. 2. 3. 4.

White fibres These fibres are of collagen protein. Unbranched fibres. Present in bundles. Less resistant to chemicals and produce.

5. Provide toughness. (b)

Yellow fibres These fibres are of elastin protein. Branched fibres. Solitary fibres. More resistant to chemicals gelatin on heating. Provide elasticity.

Adipose tissue. •

It contains closely packed cells (adipocytes) containing fat globules. They are modified Fibroblasts.

•

The Intercellular matrix is negligible.

•

The Adipocytes are two of types - 1. Monolocular, and 2. Multilocular / polylocular. Monolocular cellls stroe white fat. This fat provides lesser energy (9 Kcal/gm).

•

The multiocular cells contain brown fat which provides 20 times more energy than the white fat. Brown fat is present in hibernating animals and newly born human infants.

•

Adipose tissue provides insulation to the body-heat, cushions the body organs as a shock absorber, and is the source of reserve food material, occupying minimum space. eg. Hump in camels, tail in merino sheep, blubber in whale and elephant, and paniculus adiposes (thin and subcutaneous layer) in human.

Blood vessels

Nucleus

Monolocular adipocytes Fat globule

Cytoplasm

(A)

(B) Fig. 7.4 : (A) Adipocyte, (B) Adipose tissue

(c)

Mucous connective tissue. In this tissue, also called Wharton’s jelly, the matrix is jelly like (gelatinous), slippery (due to mucopolysaccharides) and semi-solid. eg. Cock’s comb, Vitrous humour and Umbilical cord.

ANIMAL TISSUES (HISTOLOGY) & COCKROACH, EARTHWORM AND FROG (B) Dense (Fibrous) connective tissue (a) Dense Regular connective Tissue It contains a large number of protein fibres, and is of the following types (i)

White fibrous connective tissue. It contains collagen fibres and provides strength or toughness to the tissue. eg. Duramater (Outer covering of brain ), scleroid coat of eye, renal capsule of kidney, periosteum (covering of bone ) and perichondrium (covering of cartilage). (The dermis, from which leather is obtained, contains abundant collagen-fibres). The Tendons, which connect the muscles to bones, consist of purely white (collagen) fibres.

(ii) Yellow fibrous connective tissue It contains elastin fibres and provides elasticity to the tissues eg Wall of Arteries and lungs. The Ligaments contain both yellow (mainly) and white fibres and provide bone to bone attachment. Sprain is caused by the excessive pulling of ligaments. (b) Dense Irregular Connective TissueIn such tissue the fibroblasts are present and the fibres (mostly white/ collagen) are oriented irregularly. Ex Dermis part of skin.

2. Specialized Connective Tissue A.

Skeletal Connective Tissue This tissue includes bones and cartilages The study of bones is called Osteology and the study of cartilage is called Chondrology. BONES 1. Outer covering (white fibrous connective tissue) of bones is called periosteum 2. Bone forming cells are called osteoblasts 3. Bone Protein is ‘Ossein’

CARTILAGE Outer covering (white fibrous connective tissue) of cartilage is called perichondrium.

Cartilage forming cells are called chondroblasts. Cartilage protein is ‘Chondrin’. (The sugar in cartilage is chondriotin sulphate) 4. Osteocytes (bone cells) are solitary Chondrocytes (cartilage cells) are in groups of 2’s or 3’s 5. Osteocytes are arranged on Chondrocytes are scattered in matrix. lamellae Canaliculi

Periosteum

Perichondrium Chondroblast

Outer Osteoblast Lacuna

Chondrocyte

Lamellae Osteocyte Canaliculi Inner Osteoblast

Lacuna Nucleus

Lacuna

Matrix

Marrow cavity

(A)

(B)

Fig. 7.5 : (A) T.S. bone of Frog, (B) An osteocyte, (C) C.S. Hyaline Cartilage

(C)

265

266

BIOLOGY (a)

Articular cartilage on articular surface Epiphyseal line Spongy bone

Marrow cavity

Haversian canal

blood vessels, vessels and lymphatics

Lamellae

Haversian canal

Lamellae

Periosteun Volkman's canal

Check Point 1. State two distinguishing features between: (i) Ligaments and Tendons (ii) Investing bone and cartilaginous bone (iii) Hyaline cartilage and fibrous cartilage (iv) Bone and cartilage (v) Plasma and lymph (vi) RBCs and WBCs (vii) Chief cells and oxyntic cells

BONE : Composition : Inorganic material (Salts of calcium & magnesium etc) = 45% Organic Material (Ossein and Collagen etc.) = 35% Water = 20% Calcium phosphate, in the form of Hydroxyapatite is the maximum mineral (salt) and makes about 80% of the inorganic material. Calcium carbonate is only 12-13%. (1) If a bone is kept in dilute HCl for a few days, it gets decalcified and only organic material is left. Such a bone becomes flexible and elastic. (2) If a bone is heated to redness, the organic matter is burnt and only inorganic matter (salt) is left. Such a bone becomes brittle. (3) If a bone is kept in KOH there is no effect on organic or inorganic matter. The muscles, if attached, are however removed. Types of bones 1. Replacing bone (cartilaginous bone) - When the ossification (deposition of bony material) occurs in cartilage and it is replaced by a bone, such bone is called replacing bone eg. Most of the bones of human and frog’s body. 2. Investing, dermal or membranous bone - When the ossification occurs directly in the connective tissue and the bone is formed without the development of the cartilage, such bone is called Investing bone. eg. Few bones of cranium. 3. Sesamoid bone - When the ossification occurs in a ligament or a tendon ( both fibrous connective tissue), the bone is called sesamoid bone. eg. Patella (Knee Cap). The Patella is formed by the ossification of tendons. Each long bone consist of two parts - 1. Epiphysis (articulating end) 2. Diaphysis (shaft) The Diaphysis in the center contains marrow canal with red/yellow bone marrow. The bone around the Marrow canal is compact whereas at epiphysis it is spongy with trabeculae.

Compact bone Spongy bone Epiphyseal line

Articular cartilage on articular surface (A)

Lacunae with bone cells

Canaliculi

(B)

Interstitial lamellae

(C)

Fig. 7.6 : (A) Structure of a Typical long bone, (B) Cross Section of a mammalian bone (Diagrammatic), (C) Longitudinal section of a mammalian bone (Diagrammatic)

The compact bone in mammals consist of a large number of Haversian systems. Haversian system (Osteon) is the unit of mammalian bone. It consists of - Haversian Canal (longitudinal), Circular lamellae, Lacunae with osteocytes and Volkman’s canal, the latter connecting the haversian canal transversely or obliquely. (In non-mammals the haversian system is lacking and the unit of bone is called ‘Osteon’. In birds, the bones are spongy and pneumatic, without marrow canal).

ANIMAL TISSUES (HISTOLOGY) & COCKROACH, EARTHWORM AND FROG (b)

1.

2.

3.

B. (a)

(i)

CARTILAGE : The matrix of cartilage contains proteoglycans and glycosaminoglycans, the latter including Hyaluronic acid and Chondroitin sulphate (sugar). The cartilages are of 3-types. Hyaline Cartilage • It is semitransparent or slightly bluish. • Its perichondrium is prominent. • The fibres are not visible. eg. Thyroid, cricoid and arytenoid cartilages of Larynx, Hyoid apparatus of frog, Endoskeleton of Elasmobranchi and tadpole, tracheal rings, Epiphysis (articular cartilage) etc. (In frog, the deposition of calcium salts in Hyaline cartilage forms calcified cartilage. The examples of such cartilage in frog are pubis and Supra-scapula.) Elastic Cartilage • It contains yellow fibres. • It never forms calcified cartilage. • It is elastic in nature. eg. Pinna, Epiglottis, Nose-tip and Eustachian Tube. Fibrous Cartilage • It is the Toughest cartilage. • The perichondrium is present. • Both the white and yellow fibres are well developed. eg. Inter-vertebral disc in mammalian vertebrae, and pubic symphysis in pelvic girdle. (The relaxing of pubic symphysis by the relaxin hormone helps in easy birth.) (The central and softer part of each intervertebral disc is called Nucleus pulposus).

Fluid Connective Tissue It includes blood and lymph BLOOD • Study of blood is called Haematology • Blood is 8% of the body weight ( 4 litre in a person of 50 kg.) • Osmotic pressure is equivalent to 7-8 atmospheric pressure . pH 7.4 (slightly alkaline) • Specific Gravity - 1.003 (slightly heavier than water) • Viscosity - 3-5 times than that of water. • Blood consist of - (i) Plasma, (ii) Formed (blood) elements Plasma • 55% of the blood. • It consists of 7-8% proteins, 2-3% of salts, digestive and excretory products etc., and 90% water. • The proteins mainly include albumin, globulin and Fibrinogen • Albumin is the maximum protein (3-4%) in the plasma but has minimum molecular weight. It maintains colloidal osmotic pressure of the blood. • Globulin protein can be α, β or γ type. It makes 2 to 3% of plasma proteins. The α and β-globulin bind with the hormones to transport them. The γ-globulins form antibodies. • Fibrinogen is about 0.3% and helps in blood clotting. • Remaining 2-3% of the blood plasma contains salts, hormones, digestive end products, like amino acids, fatty acids, glycerol etc., and excretory products like Urea, Uric Acid, Hippuric acid etc. It also contains bilirubin (bile pigment) which imparts yellow colour to the plasma. Following are the normal values of some important components of blood plasma. 1. Glucose - ~ 100 mg per 100 ml. 2. Cholesterol - 120-220 mg per 100 ml. 3. Bilirubin - ~0.5 mg per 100 ml. 4. Urea - 20-30 mg per 100 ml

267

Check Point 1. Fill in the blanks with suitable words/ statements: (i) ....................... cells form epithelium of thyroid follicles. (ii) Term ‘Tissue’ was coined by ....................... (iii) The two or more cells thick-epithelium is called ....................... (iv) Where wear-tear is required, the type of epithelium is ....................... (v) Mammary glands are the modification of ....................... type of glands. (vi) Histologically blood is .......................... (vii) .......................... cartilage occurs in epiglottis and pinna. (viii) Sesamoid bones are formed by the ossification of .......................... (ix) Increase in number of RBCs is called .......................... (x) .......................... is the largest blood element in human.

268

BIOLOGY

Blood

Plasma (55%)

(ii)

Check Point 1. Name the following structures: (i) Graveyard of RBCs (ii) Digestive gland which is endocrine gland also (iii) Part of the gut having Brunner’s glands (iv) Caloreceptors in the skin (v) ‘Jack of all trades’ (vi) A WBC with 2- 7 lobed nucleus (vii) Blood element that shows Rouleaux phenomenon (viii) Bone containing Haversian system (ix) Blood element that shows diapedesis (x) To which blood cell the term ‘eosinophilia’ is associated

Formed Elements (45%)

RBC Blood Elements / Formed Elements

WBC

Platelets

•

They constitute 45% of the blood and consist of RBCs, WBCs and Platelets.

•

1.

•

Number of RBC in males = 5.0 - 5.5 million/mm3 ; in females = 4.5 - 5.0 million/mm3

•

Increase in number of RBC is known as Polycythemia. It occurs at higher altitude.

•

Decrease in number of RBC or amount of haemoglobin is known as Erythropenia/ Anemia.

•

Erythropoesis, the production of RBC, in foetus occurs in Yolk Sac (in early life), liver (in middle foetal life) and in bone marrow, in last stages of foetal development.

•

The Yolk sac, Liver and Bone marrow are, therefore, called erythropoetic organs. In early childhood the RBCs are produced in bone marrow of all the bones, but at the age of 20 years, they are produced only in sternum (Breast bone), ribs, vertebrae and ilium bones of hip girdle. The longer bones are now meant for support only as they contain inactive yellow bone marrow (fatty). The process of erythropoesis is stimulated by erythropoetin hormone of kidney, and the vitamins (folic acid and B12) of B-complex.

•

The mother cells of RBCs are nucleated erythroblast. Following is the sequence of development of erythrocytes. Erythrocytes (Mature RBCs)

Red blood Corpuscles (RBCs) or Erythrocytes.

Reticulocytes (Young RBCs)

Normoblasts

(Nucleated RBCs)

Erythroblasts (Mother cells - Nucleated RBCs)

•

RBCs in mammals are Non-nucleated ((Enucleated Enucleated), Enucleated ), circular and biconcave. In camels and Llama the RBCs are, however, oval and biconvex. In lower vertebrates, like frog, the RBCs are nucleated. Amongest mammals the RBCs are smallest in musk deer. The Enucleated condition of mammalian RBCs is advantageous for accommodating more haemoglobin. The biconcave shape of RBCs is suitable for faster saturation of haemoglobin.

•

The size of human RBCs ranges from 7-8µ in diameter and is ~2µ in thickness.

•

Endoplasmic reticulum, ribosomes, Golgi bodies and mitochondria are absent in mammalian RBCs. As mitochondria are absent in RBCs, the aerobic respiration is not possible. The RBCs, therefore, respire anaerobically and transport oxygen very faithfully.

•

In slow moving blood the RBCs pile-up due to surface tension, just like the pile of coins. This is known as Rouleaux phenomenon.

ANIMAL TISSUES (HISTOLOGY) & COCKROACH, EARTHWORM AND FROG



•

The osmotic concentration of the protoplasm of RBCs is equivalent (Isotonic) to 0.8 - 0.9% NaCl solution. If RBCs are placed in a hypotonic solution (with osmotic concentration < 0.8% NaCI solution) the RBCs swell-up due to endosmosis. If the solute concentration is very low, or if RBCs are placed in distilled water, they burst. This rupturing of RBCs to release Haemoglobin is called Haemolysis or laking of RBCs. The shrinkage of RBCs, when placed in hypertonic solution is called Crenation.

•

Life span of RBCs in human is ~120 days (4 months). The worn-out RBCs are destroyed in Spleen and liver. The spleen is, therefore, also known as graveyard of RBCs.

269

Composition of RBCs •

The amount of cytoplasm in RBC is very little. The main component of RBCs is haemoglobin. The Haemoglobin is a conjugated protein, containing protein (globin) and a non-protein pigment (Haem). Its molecular weight is ~67000 Dal.

•

Connecting Concepts (The Haem is also present in Myoglobin of muscles and cytochrome ‘C’ enzyme of In chlorophyll the porphyrin is attached to Mg2+, and not Fe2+. The respiratory chain)

•

Haemoglobin forms 34% of wet RBCs and 90% of dry RBCs, by weight.

•

The amount of Haemoglobin is ~15gm/100 ml of blood (~750gm in the body having 5 litre of blood)

•

1 molecule of haemoglobin contains 4 haems and 1 globin. Each haem is formed by 1- porphyrin and 1- iron atom (Fe2+ - Ferrous form).

•

1 molecule of haemoglobin, therefore, contains 4 - Fe2+ and carries 4 molecules of oxygen.

term haem, therefore, can not be used for the pigment present in chlorophyll.

Connecting Concepts

Leghaemoglobin, different from Haem Haem above haemoglobin, is present in the 2+ root nodules of legumes. The ‘globin’ 1 Haem = 1 Porphyrin + 1 Fe Globin part of it is surprisingly synthesized by plant while ‘haem’ is synthesized Haem Haem • by Rhizobium. The leg haemoglobin, • Each molecule of globin consist of 4 polypeptide chains, 2-α chains and 2-β chains. like animals’ haemoglobin, has high affinity for O2 and thus protects Each α chain has 141 amino acids; while each β chain has 146 amino acids. the enzyme ‘Nitrogenase’, which, othewise will be inactivated by • The decrease in amount of haemoglobin is called Anaemia. O2. This enzyme (Nitrogenase), in Types of Anaemia legumes, catalyzes the reduction of N2 to NH3. (i) Nutritional Anaemia

(ii)

•

It is due to deficiency of iron in the food.

•

It is also known as microcytic anaemia as the size of RBCs becomes smaller.

• Copper is essential element for the absorption of iron in the body. Megaloblastic Anaemia •

It develops due to deficiency of folic acid and vitamin B12.

• As the RBCs do not divide, their size increases but number decreases. (iii) Pernicious Anaemia •

It is due to the deficiency ofvitamin-B12 only, and can be fatal also.

•

In this anaemia the myelin sheath (of neurons) is also not formed and the mental abnormality develops.

•

The size of RBC is more because of the decrease in the rate of cell division. Such macrocytic or megaloblastic anaemia, with mental disorder, is injurious and is, therefore, called pernicious anaemia. (iv) Sickle cell Anaemia •

It is hereditary (autosomal recessive) disorder in which β chain of the globin is affected. At 6th position in each β chain, the glutamic acid (amino acid) is replaced by valine. Such abnormal haemoglobin is called sickle haemoglobin and the RBCs become Sickle shaped. Such RBCs are not capable of carrying sufficient oxygen to the tissues.

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BIOLOGY (v)

2.

Connecting Concepts



In Leukemia or blood cancer the number of WBCs increases to more than 25,000 and abnormal corpuscles are released into the blood. A deletion of a part of longer arm of 22nd autosome (Philadelphia chromosome) is related to such cancer.

Thalassaemia • It is also an autosomal recessive disorder. • In this case either α chain or β chain of the globin is not synthesized causing minor thalassaemia (α chain not formed) or major thalassaemia (β chain not formed) . ((For details refer chapter in Vol. 2) White Blood Corpuscles (WBCs) or Leucocytes • They are all nucleated. • They lack haemoglobin, so are white. • They are wandering cells and move with the help of pseudopodia. They can come out of the capillaries through intercellular spaces of endothelium. This movement of WBCs, out of capillaries, is called Diapedesis. • They form defence system of the body. Total number of Leucocytes (TLC) – • The normal number ranges from 6000 - 9000 / mm3 • (The ratio between the number of WBCs and RBCs is 1 : 700.) •

Increase in number of WBCs is called Leucocytosis, while decrease in number of WBCs is called Leucopenia. Leucocytes (WBC)

Granulocytes or Polymorphonuclear Leucocytes

Agranulocytes or Monomorphonuclear Leucocytes

Lymphocytes  1.

(a)

Monocytes

Acidophils

Basophils

Neutrophils

WBCs are of 2-types Agranulocytes These cells lack cytoplasmic granules (groups of lysosomes - containing various types of enzymes) and are of two types - (a) Lymphocytes, (b) Monocytes Lymphocytes •

These cells are of two sizes, i.e. 7-8µ and 12-15µ.

•

They have rounded nucleus.

•

They are formed in lymphatic tissues and bone marrow.

•

Their number is higher in lymph than in the blood.

•

They are of 2-types, i.e., T-cells and B-cells (for details refer Chapter 8 in Vol. 2)

•

Their mother cell are called lymphoblasts.

• They (B-cells) synthesize antibodies and are, therefore, important for immune system. (b) Monocytes •

2.

They are the largest / biggest WBCs, or the largest blood elements in human body (size ranges from 15-20 µ) µ • Nucleus of these cells is kidney shaped. • They are formed in bone marrow and connective tissue, from monoblasts, the mother cells. • They are Phagocytic cells. In connective tissue they become large eating - machines, called macrophages. Granulocytes These cells contain cytoplasmic granules, and are produced from myeloblasts, the mother cells. The size of granulocytes ranges from 12-15µ.

ANIMAL TISSUES (HISTOLOGY) & COCKROACH, EARTHWORM AND FROG They are of 3-types - (a) Acidophils

(b) Basophils

271

(c) Neutrophils

side Surface

erythrocyte (no nucleus)

lymphocyte

monocyte

mononuclear leucocytes

acidophil

basophil

neutrophil

polymorphonuclear leucocytes or granulocytes

Human Blood Cells Fig. 7.7 : Human Blood Cells

(a)

Acidophils • They take-up acidic stain (eg. eosine) and so are also called as Eosinophils or oxyphils. • They have bilobed nucleus. • They produce antitoxins against allergens, the chemicals that cause allergy. • The increase in number of acidophils during allergy or parasitic infection is called Eosinophilia. (b) Basophils • They take-up basic stain (eg. methylene blue). • They have ‘s’ shaped, indistinct nucleus. • They produce heparin and histamine and are, therefore, also known as Mast cells of the blood. (c) Neutrophils • They take-up neutral stain (eg. neutral red ). • The nucleus in these cells is 2-7 lobed (polymorphs). The term ‘polymorph’can be used for all granulocytes due to more than I-lobed nucleus. • They are phagocytic cells. (About 5% of the neutrophils in females show Barr body as Drum-stick.) Differential leucocyte count (DLC) – 1. Neutrophils 60-65% (Maximum in number) 2. Lymphocytes 20-30% 3. Monocytes 4-8% 4. Acidophils 1-4% 5. Basophils 0-1 % (Minimum in number) The neutrophils and monocytes are phagocytic cells and increase during bacterial and viral infection. The acidophils increase during allergy or parasitic infections. Life span of Leucocytes  Life span of granulocytes (acidophils, basophils and neutrophils) is 4-8 hours.  The life span of monocytes in blood is 10-20 hours. In connective tissue they can survive for months.  The lymphocytes, as memory cells, may survive for years. 3. Platelets (Thrombocytes) • They are the smallest blood elements (cell fragments), and their size ranges from 3-4µ. • They are non-nucleated ( enucleated) and irregular in shape. • Their mother cells are called megakaryocytes. • Their number ranges from 3-4 lakhs/mm3 (0.3 - 0.4 million/mm3) • Their life span is 2-5 days. • The increase in number of platelets (thrombocytes) is called Thrombocytosis. • Their decrease is called Thrombocytopenic purpura. • They release thromboplastin or thrombokinase for blood clotting.

Connecting Concepts WBCs are the only nucleated elements in mammalian blood. In frog, the RBCs and thrombocytes are also nucleated.

272

BIOLOGY (b)

LYMPH The extra cellular fluid (ECF), Interstitial fluid or tissue fluid is ~20% of the body weight (14 litre in a person of 70 Kg.). This fluid mainly includes lymph and plasma Lymph + Plasma = ECF (~11 ltr) (~3 ltr)

(~14 Itr)

(The ECF when flows in lymphatic vessels, is called lymph.) Blood has both intracellular fluid (inside blood corpuscles) and extra cellular fluid (as plasma). (Intracellular fluid (ICF) makes about 40% of the body weight (28litres in a person of 70 kg.). Thus ICF is twice of ECF.) •

The 50% of the lymph is produced in liver.

•

Lymph contains more lymphocytes and less protein than blood. It is generally represented as ‘Blood minus RBCs’ or ‘Plasma plus WBCs’

•

Lymph contains fibrinogen and, therefore, can clot like plasma.

•

Lymph differs from plasma, in having WBCs, and from ‘Serum’, in having bothfibrinogen & WBCs.

•

Lymph helps in exchange of gases or nutrients between blood and cells /tissues.

•

The absorption of fat products also occurs through lymph of Lacteals of intestinal villi.

III NERVOUS TISSUE •

This tissue is purely ectodermal in origin.

•

The nervous tissue first appeared in the members of Coelenterata (Cnidaria) and there the nerve cells are non-polarized.

•

Nervous tissue has least regeneration power.

•

The structural and functional unit of nervous tissue is Neuron or Nerve cell (The number of neurons in human nervous system is ~1012, i.e. 1 trillion).

Structure of neuron It consists of three parts. 1.

Dendrites (Dendrons)

2.

Cyton (Cell body or Perikaryon)

3. Axon In polarized fibres the nerve impulse travels from dendrite to cyton, and from cyton to axon. The neurons are of 3-types. 1.

Unipolar or Pseudo unipolar neurons In such neurons, single process arises from the cell body and bifurcates to form axon and dendtrite. eg. Neurons of dorsal root ganglion of spinal cord.

2.

Bipolar Neurons In such neurons, two processes, one dendrite and one axon, arise from the cell body (cyton) eg. Neurons of Retina and membranous labyrinth (Internal ear).

ANIMAL TISSUES (HISTOLOGY) & COCKROACH, EARTHWORM AND FROG

Muscle

A

A

A C

C

C D

D

D

Multipolar Pseudounipolar Bipolar neuron neuron neuron Different type of neurons Fig. 7.8 : Different type of neurons

3.

Multipolar Neurons Such neurons have one axon and two or more dendrites. More than 99% of the neurons are multipolar type. The neurons are surrounded by various types of supporting cells or packing cells called Neuroglia. The number of glia cells is 30-40 times the number of neurons but they are so small that they make up only half of the volume of Neural Tissue. The glia cells around the neurons of peripheral nervous system are called Schwann cells. The glia cells of central nervous system are of 3-different types. 1. Astrocytes - These are star shaped cells forming blood-brain barrier for transportation of nutrients from blood to the brain (CNS). 2. Microglia - These are phagocytic cells and remove debris from the nervous tissue. 3. Oligodendrocytes - They secrete myelin-sheath around many nerve fibres, together. Structure of Neuron • Cyton or cell body contains groups of ribosomes and rough endoplasmic reticulum, called Nissl granules. Such granules are also present in the dendrites but absent in axon. They help in protein synthesis. The presence of Nissl granules is the characteristic feature of neurons. • The centrosome is absent in the cyton and hence, the neurons can not divide. • The cytoplasm and the cell membrane of axon are called axoplasm and axolemma respectively Cyton Axon hillock C.N.S.

Axoplasm Schwann cell P.N.S.

Terminal Buttons

Myelin sheath Axon

Dendrites

Oligodendrocyte Nissl's granules (glia cell)

Neurilemma Node of Ranvier

Internode

Structure of a (multipolar) neuron

Fig. 7.9 : Structure of a (multipolar) neuron

•

The long fibre (eg. Axon / dendrite) may be grey (non-myelinated) or white (myelinated). The myelin sheath in PNS is secreted by Schwann cells. (The myelinated fibres are also known as Medullated fibres.)

•

The covering formed by Schwann cells around axon is called Neurilemma.

273

274

BIOLOGY •

Due to discontinuous myelin sheath around axon ( in myelinated fibres ), the fibres are differentiated into nodes and internodes. At nodes the myelin sheath is absent but neurilemma is present.

Ganglia - The Ganglion is a group of cytons or cell bodies. In brain (CNS) such groups of cytons are called nuclei. Nerves - The nerve is a group of axons (mainly). In brain such groups of axons are called tract. Structure of a nerve - The outermost connective tissue-covering of the nerve is called Epineurium. There are several bundles of neurons embedded in the epineurium. Such bundles are known as nerve fasciculi. Each nerve fasciculus has a connective tissue covering called Perineurium. Individual neuron is also surrounded by connective tissue covering called Endoneurium. So from outer to inner the connective tissue coatings in a nerve are Epineurium

Perineurium

Endoneurium

Epineurium Perineurium Endoneurium Axon (Neuron)

Fasciculi Blood vessels T. S. Fig. of a7.10 nerve : T. S. of a nerve Type of nerves On the basis of their nature/function, the nerves are of 3-types. 1.

Sensory nerves - The impulse in such nerves is carried from receptor ( skin, retina etc ) to the CNS eg. Optic Nerve.

2.

Motor nerves - Such nerves carry impulses from CNS to the effector organ (Muscle/glands) eg. Trochlear Nerve.

3.

Mixed nerves - In such nerves, some fibres carry impulses towards CNS and others away from CNS. eg. Vagus Nerve. C

C

N D C

S

A

Sensory nerve

C A

N A

C

D

S

D

Motor nerve

A

C

Mixed nerve

Fig. 7.11 : Type of Nerves (D - Dendrites, C - Cyton, A - Axon)

MUSCULAR TISSUE   

It is Mesodermal in origin (exception - iris muscles - ectodermal). It forms 40 - 50% of the body weight in human. Total Number of muscles in human body = 639.

C

D

N S

ANIMAL TISSUES (HISTOLOGY) & COCKROACH, EARTHWORM AND FROG In human body 

The largest/ biggest muscle is Gluteus maximus (hip muscle).



The longest muscle is Sartorius (back muscle).



The strongest muscle is Masseter (Jaw muscle).



The longest smooth muscle is Rectus abdominis.



The shortest muscle is - Stapedial muscle.

Special/Important muscles 

Auricular muscles – in pinna (not in auricles)



Papillary muscles – In ventricles of heart (not in pupil)



Rectus muscle – In eyeball (not in rectum)



Gastronemius muscle – In Shank (Calf) region (not in stomach).



Intercostal muscles – In between ribs



Bicep and Triceps – In upper arm.



Quadricep – In thigh region.



Segmental muscles (Vestigial in human) – on either side of vertebral column.



Pectoralis major and pectoralis minor – Flight muscles in birds, or chest muscles in mammals.

In muscles the structural and functional units are different. The structural unit of muscular tissue is muscle fibre or muscle cell.

Nucleus Sarcolemma

Myofibril

Sarcosome

Sarcoplasm A muscle fibre (or Muscle cell)

Fig. 7.12 : A muscle fibre (or Muscle cell)

The important components of muscle fibre are : Sarcolemma – Plasma membrane of the muscle fibre. Sarcoplasm – The protoplasm of the muscle fibre. Myofibrils – Sub unit of muscle fibre. Sarcosome – The mitochondria of muscle fibre. The Number of nuclei varies in different muscle fibres. The skeletal muscles of the vertebrates also contain an energy rich compound, i.e. Phosphogen or creatine phosphate. (In case of majority of higher invertebrates, it is Arginine phosphate). Types of muscles —

(A)

(B)

(C)

Fig. 7.13 : (A) Cardiac muscle, (B) Striated or skeletal muscle, (C) Visceral muscle

275

276

BIOLOGY CARDIAC MUSCLE

SKELETAL MUSCLE

1.

Present in myocardium of the heart.

2.

Sarcolemma is ill 2. defined Muscle fibres cylindrical 3. but branched with intercalated discs at the junctions. Faintly striated 4.

3.

4.

5. 6. 7. 8.

Involuntary in nature Contraction slow but rhythmic Fibres with 1 to 2 nuclei Fatigue does not develop.

1.

Attached to skeleton, except the diaphragm and tongue- muscles.

VISCERAL MUSCLE 1. Present in visceral organs like gut, blood vessels and urinary bladder. 2. Ill defined

Sarcolemma well defined. Muscle fibres cylindrical, 3. Muscle fibres fusiform unbranched and inor spindle shaped, bundles unbranched and solitary.

5. 6.

Fibres Striated or striped (dark and light bands present) Voluntary in nature Contraction quick

4. Unstriated (Dark and light bands absent), so called smooth muscles. 5. Involuntary in nature 6. Contraction slow

7. 8.

Fibres multinucleated Fatigue develops

7. Fibres uninucleated 8. Fatigue does not develop

Antagonistic sets of skeletal muscles – 1. Flexor and Extensor muscles – Flexor (eg. Bicep) is for bending and extensor (eg. Tricep) is for straightening, the arms at elbow. 2. Sphincter and Dialator muscles Sphincter reduces while dialator increases the diameter of the opening (eg. Circular and radial muscles of iris) 3. Adductor and Abductor muscles Adductor draws the limbs towards the body axis while abductor takes them away. 4. Levator and Depressor muscles Levator takes the body part vertically upward whereas the depressor brings it down. 5. Protractor and Retractor muscles Protractor takes organs forward from its normal position while retractor brings them back (eg. Muscles of lower jaw for to-and-fro movement). 6. Pronator and Supinator – Pronator brings palm backward and downward whereas supinator brings it forward and upward Skeletal Muscle fibresIn birds and mammals (Homeotherms) these fibres are functionally of two types – 1. 2. 3. 4. 5.

RED MUSCLE FIBRES* Thin fibres Myoglobin present

WHITE MUSCLE FIBRES Thick fibres Myoglobin absent

Mitochondria – many Mitochondria – few Contraction slow Contraction fast Fatigue develops slowly Fatigue develops early eg. Flight muscles in kite and back eg. Flight muscles in house sparrow and muscles in human eyelid muscles in human

* Since such muscle (fibres), having plenty of mitochondria, utilize large amount of oxygen (stored in them) for the production of ATPs, they are also known as Aerobic Muscles.

ANIMAL TISSUES (HISTOLOGY) & COCKROACH, EARTHWORM AND FROG Smooth Muscles fibres In birds and mammals (warm blooded animals) these fibres are also functionally of two types – MULTI UNIT TYPE All the muscle fibres contract independently as a separate unit. eg. Muscles fibres of hair roots and the wall of blood vessels

SINGLE UNIT TYPE All muscle fibres contract together as a single unit eg. Muscle fibres of Urinary bladder, gut and uterus.

ORGAN HISTOLOGY 1. Liver •

It is the largest gland of the body and weighs 1-2 kg.

•

It has maximum regeneration power (Compensatory regeneration).

•

It is endodermal in origin and lies in right side of the abdominal cavity.

•

In human, the liver is 4-lobed (Left Lobe, Right Lobe, Quadrate Lobe and Caudate Lobe). In Frog and Rabbit it is 3 and 5 lobed respectively. The gall bladder is attached to the right lobe of the liver.

•

The structural and functional unit of liver is lobule. villi

mucosa

submucosa muscularis externa serosa

lacteal – usually collapsed in fixed material smooth muscle fibres goblet cells columnar epithelium – mucous membrane lamina propria crypts of Lieberkühn – intestinal gland Paneth cells muscularis mucosa blood vessel circular muscle layer connective tissue sympathetic ganglion of Auerbach's plexus longitudinal muscle layer Fig. 7.14 : T.S. ileum

•

Each lobule is surrounded by a connective tissue covering, called Glisson’s capsule (In human the Glisson’s capsule is not developed). In the center of lobule there is a branch of hepatic vein, also known as intra-lobular vein. In between adjacent lobules there are Interlobular ducts or portal canals containing branches of hepatic artery, lymphatic vessel, bile duct and hepatic portal vein. The hepatic cells (hepatocytes) are arranged in sheets, each 2-cells-thick. Amongst the sheets of hepatic cells there are blood lacunae and sinuses (sinusoids). The phagocytic cells, Kupffer Cells, lie in Glisson’s capsule and at the border of sinuses.

277

278

BIOLOGY

Polygonal lobule Portal canal/Interlobular duct Liver cords (usually one or two cell thick) Sinusoids (small sinuses) Central vein (Br. of hepatic vein) or Intralobular vein Hepatic artery Bile duct Hepatic portal vein

Fig. 7.15 : C. S. human liver

Functions : (i) Phagocytosis - Kupffer cells are phagocytic cells and remove pathogens and toxic material from the blood. (ii) Excretion - Liver is not excretory organ but synthesis of urea, uric acid, creatinine etc. occurs in liver. The bilirubin (excretory product) is also formed in liver. (iii) Storage - It stores vitamin A, D, B12 , Iron (as ferritin), blood and glycogen etc. (iv) Haemopoesis - In foetus, the liver is a haemopoetic organ and produces RBCs, WBCs and platelets. (v) Production - It produces bile juice, which is later on concentrated in Gall bladder, and heparin, an anticoagulant. It also produces many plasma proteins like albumin, prothrombin and Angiotensinogen. About 50% of the body lymph is produced in liver. It synthesizes fatty acids, cholesterol and phospholipids also. (vi) It is also the seat of various metabolic reactions like Glycogenesis, Glycogenolysis, Gluconeogenesis, Deamination, Cori-cycle etc. It is also important site for β-oxidation of fatty acids and degradation of cholesterol to form cholic acid of bile. It is the busiest organ of the body. It receives both oxygenated and deoxygenated blood. The blood supply to liver in human is ~1500 ml per minute.(1000 ml. from hepatic portal vein and 500 ml. from hepatic artery).

2. Spleen •

It is mesodermal in origin.

•

It lies close to fundic stomach, in the left hand side of the abdominal cavity. (In frog it is close to large intestine).

•

Spleen is the largest lymphatic organ (15 cm. in diameter and 150 g. in weight)

•

Unlike other lymphatic organs, it is not differentiated into cortex and medulla.

•

The lymphatic sinuses and lymphatic vessels are also lacking in this organ.

It consists of outer red-pulp (containing RBCs) and inner white-pulp (lacking RBCs). The nodules (germinal centres) in the white pulp synthesise lymphocytes. Functions – (i) Biological filter - It removes pathogens, like bacteria, and foreign material from the blood. Its phagocytic cells belong to Reticulo-endothelial system. (ii) Blood Bank - It is called blood bank and stores blood in Frog. In human the maximum blood is, however, stored in liver. (iii) Haemopoetic organ - In human foetus and adult Frog, the blood elements are manufactured in spleen. It also stores RBCs. (iv) Graveyard of RBCs - The worn out RBCs, whose life span is completed, are dumped in this organ. (v) Immunological functions - It is the centre for lymphocyte production, which produce plasma cells and hence antibodies. It plays important role in immunity. •

ANIMAL TISSUES (HISTOLOGY) & COCKROACH, EARTHWORM AND FROG

3. Pancreas • • • • • •

•

It, like liver, is endodermal in origin. It is the IInd largest digestive gland, only next to liver, in the body (~ 15 cm in size) It lies in the coil of duodenum in the abdominal cavity. It is a Heterocrine (mixed) gland, containing both exocrine and endocrine parts. On the basis of structure, it is a compound tubulo-alveolar gland gland. Its exocrine part consists of a large number of Acini (sing. Acinus) which produce pancreatic juice. (The endocrine part i.e., Islets of Langarhans, has been discussed with hormonal coordination, in Chapter 19). Pancreatic duct, before opening into duodenum, joins Common bile duct and forms Ampulla of Vater, having ‘sphincter of Oddi’ at the common opening.

Gall bladder

a-cells

Cystic duct Hepatic duct

Common bile duct

Acini

Ampulla of Vater Sphincter of Oddi

b-cells d-cells

Duodenum

Aciner cells

Pancreatic duct Common pancreatic (Duct of Wirsung) bile duct (A)

(B)

Fig. 7.16 : (A) Bill, Hepatic and Pancreatic ducts, (B) C. S. pancreas

Types of Exocrine glands : On the basis of structure the exocrine glands can be differentiated into 2 - broad categories, i.e. simple glands and compound glands (i) Simple glands - In such glands the duct (non-secretory part) is unbranched unbranched. (a) Simple Unbranched glands - Their secretory part is also unbranched. (i) Tubular Uncoiled -ex. Crypts of Lieberkuhn. Coiled - ex. Sweat glands. (ii) Alveolar - ex. Mucous and poison glands in Frog’s skin.

Simple coiled Tubular

Simple branched Tubular

Simple alveolar

Simple glands

Simple Compound branched tubular alveolar

Compound alveolar

Compound tubuloalveolar

Compound glands

Fig. 7.17 : Types of exocrine glands

(b) Simple Branched glands - Their secretory part is branched. (i) Tubular - ex. Gastric glands. (ii) Alveolar - ex. Sebaceous glands and Meibomian or Tarsal glands. (ii) Compound glands - In such glands the duct (non-secretory part) is branched branched. (a) Tubular - ex. Non lactating mammary glands, Brunner’s glands. (b) Tubulo-alveolar - ex. Lactating mammary glands, parotid (salivary gland) and Pancreas etc. (c) Alveolar - Sub-maxillary salivary glands

279

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BIOLOGY

4. Gut (Alimentary Canal) There are following 4-coatings (from inner to outer) in gut lining. (i)

Tunica mucosa - It is differentiated into Epithelium, Lamina propria and muscularis mucosa. It contains digestive glands. The epithelium in most part of the gut is simple columnar type. The Lamina Propria contains lymphatic tissue (GALT - Gut Associated Lymphatic Tissues) and various types of cells, like Lymphocytes, Plasma cells, Eosinophils etc. It, however, lacks Blood vessels and nerves.

(ii) Tunica sub-mucosa - It consists of connective tissue with blood vessels, nerve fibres and nerve plexuses (eg. Meissner’s plexus). (iii) Tunica muscularis - It usually contains an inner layer of circular muscles and outer layer of longitudinal muscles. The Auerbach’s plexuses are usuaIly present between these two layers of smooth muscles. (iv) Tunica externa - It consists of a thin layer of connective tissue covered with Visceral epithelium or Serosa (formed from coelomic mesoderm or peritoneum) and is attached to mesenteries. Inner circular muscle layer Outer longitudinal muscle layer

Epithelium Lamina propria Mucosa Muscularis mucosae Submucosa Muscularis externa

Meissner's plexus Auerbach's plexus Serosa Fig. 7.18 : General Plan of alimentary canal

(A) Oesophagus •

The epithelium or mucous membrane of Tunica mucosa is formed by stratified squamous cells.

•

Tunica submucosa is thin.

•

Tunica muscularis has voluntary (striated) muscles (upper 1/3rd part), voluntary and involuntary muscles (middle 1/3rd part) and involuntary (smooth) muscles (lower 1/3rd part).

(B) Stomach •

When stomach is empty the tunica mucosa forms longitudinal folds, called Rugae.

•

The gastric glands in Tunica mucosa are simple tubular and branched. The neck of the glands contain mucus secreting cells; the body of the glands has chief (Zymogen) and parietal (Oxyntic) cells. The cells at the bottom are Argentaffin (enterochromaffin). The latter are endocrine cells of the stomach.

•

The chief cells produce digestive enzymes.

•

The parietal cells secrete intrinsic factor of Castle and HCl. (for detailed functions please refer ‘Animal Nutrition’, Chapter 12)

•

Tunica muscularis of stomach contains inner oblique, middle circular (thickest) and outer longitudinal layer of smooth muscles.

ANIMAL TISSUES (HISTOLOGY) & COCKROACH, EARTHWORM AND FROG Rugae Columner epithelium Gastric pits Lamina propria Cardiac glands Muscularis mucosa Adipose tissue Blood vessels Circular muscle layer Connective tissue

mucosa

sub-mucosa muscularis externa

Longitudinal muscle & oblique muscle layer

serosa (A)

surface epithelium of gastric mucosa

gastric pit

mucoid neck cells middle third - neck

mucoid material chief or peptic cells parietal or oxyntic cells

lower third-secretes pepsinogen and dilute hydrochloric acid (B)

Fig. 7.19 : (A) T. S. stomach, (B) Fundic (Gastric) gland

I.

(C)

(D)

II. (E)

(F)

Small Intestine : • This part is characterized by the presence of villi of various shapes. • In small intestine tunica mucosa consists of 4-types of cells. 1. Enterocytes or absorptive cells - They have microvilli to form brush bordered epithelium and increase the surface area for absorption. They also secrete digestive enzyme. 2. Goblet Cells - These are single celled, egg shaped glands and secrete mucus. 3. Paneth Cells - They secrete digestive enzymes, for digesting the wall of bacteria. 4. Argentaffin cells - They are endocrine cells. Duodenum • The Lamina Propria is thick, having lymphatic nodules, called Peyer’s Patches. • The crypts of Lieberkuhn are present in mucosa part. . • The characteristic mucus secreting cells of duodenum, the Brunner’s glands, are embedded in submucosa part. These glands, however, open into crypts of Lieberkuhn. • The Tunica mucosa is thrown into leaf shaped villi. • Tunica muscularis does not have oblique muscles. • The Goblet cells are also few in number. Ileum • Its villi are tubular. • The Goblet cells are more in number. • Brunner’s glands are absent. • The crypts of Lieberkuhn, with abundant paneth cells, are present. • The Peyer’s patches are also present in Lamina propria. • Tunica mucosa is thrown into circular folds, (Plica circularis) called ‘Folds of Kerckring’. Large Intestine • The villi are absent in this part of intestine. Colon (large intestine) • The crypts of Liberkuhn are present. • The mucus secreting cells, goblet cells, are innumerable. • Paneth cells are absent. • The longitudinal muscles of Tunica muscularis form 3-longitudinal bands, called Teniae Coli, to make colon sacculated. Anal canal • Tunica muscularis is formed by striated or voluntary muscles. • The crypts of Lieberkuhn and villi are absent. • The mucous membrane is thrown into longitudinal folds, called ‘Rectal columns of Morgagni’.

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BIOLOGY

INTEGUMENT It is the part of body wall and consists of skin and its derivatives (glands and exoskeleton) BODY WALL Integument

Skin

Epidermis

Musculature

Peritoneum

Skin Derivatives

Dermis

Glands

Exoskeleton

The skin is ectomesodermal in origin and consists of epidermis (ectodermal) ectodermal) and dermis ectodermal (mesodermal). mesodermal mesodermal). MAMMALLIAN SKIN 1 Epidermis - It is stratified squamous epithelium and, from inner to outer, consists of following layers (i) Stratum germinativum or stratum Malpighii (Inner most) (ii) Stratum spinosum (iii) Stratum granulosum (iv) Stratum lucidum (v) Stratum corneum (outer / top most). (i) Stratum germinativum (Stratum Malpighii) • It is simple columnar epithelium. • It is the only meristematic layer in epidermis (the mitotic divisions are faster during night). • All other layers, cutaneous glands, and the exoskeleton develop from this layer. • The pigment bearing cells, melanocytes, are present in between these cells. (ii) Stratum spinosum • It is a prickly layer with polyhedral cells bearing minute spine like structures. (iii) Stratum granulosum • Its polygonal cells contain granules of keratohyalin protein. (iv) Stratum lucidum • Due to degeneration of nuclei, the cells are non-nucleated. These cells also have eleidin (a transparent protein and precursor of keratin), that makes the layer lustrous / shiny. • It is prominent and thick in heel. (v) Stratum corneum • It consists of squamous cells. • Its cells are dead, flat, non-nucleated and contain keratin protein (keratinized). The dead cells make the skin germ proof. The keratin is important for water proofing.

Stratum Corneum Stratum lucidum Stratum Granulosum Stratum Spinosum Stratum Malpighii Dermal papilla Sensory structure Blood vessels

Hair shaft Hair follicle Melanocyte Sebaceous gland Arrector pili muscle Hair bulb Hair papilla Adipose tissue

Sweat gland Fig. 7.20 : V. S. mammalian skin

ANIMAL TISSUES (HISTOLOGY) & COCKROACH, EARTHWORM AND FROG Derivatives 1. Sweat glands •

They are also known as sudorific glands.

•

Structurally they are simple, unbranched/branched, coiled and tubular.

•

They are merocrine (mainly) or apocrine (in axilla and pubis) and produce watery secretion, which diffuses out of the cells without cell injury.

•

The sweating by evaporation helps in cooling of the body.

In Rabbit the sweat glands are concentrated on lips; in deer on base of tail; in dogs / cats on paws. In human they are maximum on palm and sole and are absent on lips and glans penis. Sebaceous glands

•

2.

3.

•

These glands secrete sebum which is germicidal due to the presence of lysozymes.

•

They are holocrine glands and release oily secretion into hair follicles.

•

Structurally they are simple, branched and alveolar type.

•

They are absent on sole/palm.

• The cells of these glands synthesize vitamin D with the help of UV radiation. Exoskeleton •

There are various forms of exoskeleton in mammals, like hoofs, horns, nails/claws, scales/ spines and hair etc.

•

All develop from stratum germinativum of epidermis and hence, are ectodermal in origin. (The antlers are bony structures and not skin derivatives. They are formed from mesoderm).

•

The outer layer of exoskeleton is keratinized and contains dead cells.

•

Mammalian hair, the ectodermal structures, are covered with cuticle. They are differentiated into outer cortex and inner medulla. The pigment (melanin) is present in cortex.

•

The hair coat in mammals is called Pelage. Due to the absence of medulla in human, the hair are hollow or tubular. These hair are absent on palm/sole, lips, glans-penis, and teats etc. (Study of hair is called Trichology).

•

The greying of hair occurs due to degeneration of melanin.

•

The contraction of arrector pili muscles causes hair erection (Goose flesh).

• II.

Each hair grows at the base of shaft (hair root) which is called hair bulb. The hair papilla receives blood and nerve supply. Dermis -

•

It is differentiated into outer papillary layer and inner reticular layer. The papillary layer is compact with finger like projections, the papillae, whereas the reticular layer consists of loose connective tissue which merges with the sub-cutaneous fat.

•

Below dermis, there is a thin layer of fat, called Paniculus adiposes.

•

The leather in mammals is produced from dermis part of the skin.

•

Sensory Structures - Most of the sensory structures in the skin are ‘encapsulated dendrites’ and are embedded in dermis. They all are ectodermal in origin. Meissner’s Corpuscles - They are sensory for touch (Thigmoreceptors). Merkel’s Discs - They are also sensory for touch or soft pressure. Paccinian Corpuscles - They are sensory for pressure. ((Baro receptors) Krause end bulbs - They are sensory for cold ((Frigidoreceptors). End bulbs of Ruffini - They are sensory for warmth (Caloreceptors) Free nerve endings - They are sensory for pain ((Algesireceptors) Due to variety of functions, eg. protection, temp. regulation, sensory, minimizing water loss etc., the skin is called ‘Jack of all trades’.

(i) (ii) (iii) (iv) (v) (vi)

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BIOLOGY

Frog’s Skin The epidermis (ectodermal) is thin and contains 2-layers only; inner Stratum Malpighii or stratum germinativum and outer Stratum corneum.



The Stratum Malpighii is simple columnar epithelium and due to cylindrical cells, is also known as Stratum cylindericum. It is the only meristematic layer in skin.



Stratum corneum consists of stratified Squamous epithelium.



The exoskeleton in frog is absent.



The dermis (mesodermal) is differentiated into outer stratum spongiosum and inner stratum compactum.



The stratum spongiosum contains loose connective tissue and pigment bearing cells, the chromatophores. The chromatophores are of 3-types (i) Melanophores - They contain blue/black/brown pigments. (ii) Lipophores /Xanthophores - They contain red/orange/yellow pigments. (iii) Guanophores /Irridocytes - They are colourless or transparent. Due to colour changing ability (metachrosis), the frog resembles with the background (camouflage). The stratum compactum has closely packed white fibres. It also contains nerve fibres and blood vessels. The frog can be skinned easily as its skin is not fused with the musculature. There are partitions filled with the lymph in between skin and musculature. Such skin can not yield leather. Glands - There are 2-types of glands in the skin of frog. Both develop from stratum malpighii and hence are ectodermal in origin.

ot .c om



sp



og



ad

em

y.

bl



Poison gland

ht tp

s:

//n

ee tm

ed

ic

al

ac

Stratum Corneum Stratum Malpighii Chromatophores

Mucous glands Stratum spongiosum

Blood vessels

Stratum copactum

Lymph spaces

Musculature

Fig. 7.21 : V. S. Frog’s skin

(i)

Mucous glands - They are simple alveolar, and are distributed all over the body. They secrete mucus which keeps the skin moist for Cutaneous respiration. The secretion also makes the skin slippery for escaping from the predators. (ii) Poison glands - They are also simple alveolar type and are mainly concentrated on the shoulders. (In toad these glands together form parotid glands on shoulders) Frog can absorb water through skin but cannot regulate its body temperature. The sweat glands are lacking. The vitamin D can also not be synthesized in its skin. The subcutaneous storage of fat is also absent.

ANIMAL TISSUES (HISTOLOGY) & COCKROACH, EARTHWORM AND FROG

Part-II : Cockroach, Earthworm and Frog While going through the chapter pay special attention to the following – Terms and definitions – 1. Typhlosole 2. Holonephridia 3. Nephrostome 4. Phaosome 5. Mosaic image 6. Ecdysis 7. Paurometabola 8. Metachrosis Differences – 1. Blatta orientalis and Periplanata americana 2. Anal style and Anal cerci 3. Ocelli and Ommatidia 4. Aspiration and Inspiration 5. Blood and Haemolymph 6. Apposition and Superposition (Image) 7. Prostomium and Peristomium Structure / Parts – 1. Elytra 4. Stomodeal Valve 7. Corpora allata 10. Corpora Bigemina

2. 5. 8.

Notum Peritrophic membrane Gonapophyses

3. 6. 9.

Arolium Alary muscles Bidder’s Canal

COCKROACH Taxonomic position Phylum Class Order Genus Species

-

Arthropoda Insecta Dictyoptera Periplanata americana



There are two main types of cockroaches in India, i.e. Periplanata and Blatta.



The term Periplanata was given by Burmeister and the term Blatta was given by Linnaeus.



The most common cockroach in India is Periplanata americana. Blatta orientalis is found in oriental region but is less common in India. Blatta orientalis

Periplanata americana

1. It is oriental and Indian cockroach. 2. 3.

4. 5. 6.

It is american cockroach but is cosmopolitan in distribution. It is black, so called Black-beetle. It is dark brown in colour. In males the wings cover half of the Wings are larger and cover whole of the body, whereas in females the wings are abdomen rudimentary It can not fly. It can fly. Legs do not have arolium ((pulvillus) for Arolium or pulvillus is present at the terminal end of each leg. moving on the smooth surface. Diploid chromosome number Diploid chromosome number (2n) = 48. (2n) = 34

BODY STRUCTURE Like other insects the body of cockroach is also differentiated into 3-parts, i.e. head, thorax and abdomen.

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BIOLOGY

Head 

    

The head consists of 6-segments (fused) and is downwardly directed ((Hypognathous). The exoskeleton plates on the head are Vertex (epicranium), Frons, Gena and Clypeus. Vertex has an inverted Y-Shaped epicranial suture. The antennae (1 pair) are many segmented and differentiated into 3-regions, i.e. scape, pedicel and flagellum. There is one pair of compound eyes, one on either side of the head. Each eye is sessile and contains about 2,000 visual units (Ommatidia). There is 1-pair of simple eyes (ocelli), also which are vestigial and do not form images. The mouth parts in cockroach are Cutting and Chewing type (Mandibulate). They consist of upper lip (Labrum), lower lip (Labium), mandibles, maxillae and hypo-pharynx. The hypo-pharynx (tongue), mandibles and labrum are unjointed structures whereas maxillae and labium are jointed structures. The jointed structures are based on ‘Biramus plan’.

Labrum Mandible

Mandible

Duct of Salivary galnd

C S

Hypopharynx para glossa

Labial palp (3-Segtd) prementum Maxilla mentum (1st) Submentum

Glossa Maxilla (1st)

Cardo Stipe Lacinia Galea Maxillary palp (5 segtd)

Labium Fig. 7.22 : Mouth parts of cockroach (Cutting and Chewing type)



Each maxilla (1st maxilla) consists of two podomeres, cardo and stipe. The 2-branches (rami) which arise from stipe, are maxillary palp and lacinia-galea. The maxillary palp is 5-jointed and is sensory for smell (olfactory receptor).



Labium is formed by the fusion of two 2nd maxillae. Each half of labium has 3-podomeres, i.e. prementum, mentum and sub-mentum. The two rami are, outer labial palp and inner glossa-paraglossa. The labium palp is three segmented and is sensory for taste (gustatoreceptor). The glossa and paraglossa of labium are together called Ligula.



(Lingula is a living fossil and belongs to a minor phyla, Brachiopoda) Forewings (Elytra /tegmina) Epicranial suture Hind wings (Membranous) Antenna vertex Compd eye

neck Anal cercus

Ocellus Frons Clypeus Labrum

Abdomen (10-segmented)

Gena 3-pairs of walking legs

Fig. 7.23 : External features of Periplaneta americana (Diagrammatic)

ANIMAL TISSUES (HISTOLOGY) & COCKROACH, EARTHWORM AND FROG

Thorax 

It is differentiated into prothorax, mesothorax and metathorax.



The exoskeleton of each segment is called Sclerite and consists of dorsal plate (Tergum/ Notum), ventral plate (Sternum) and lateral plates (Pleuron)



There are 2-pairs of wings in cockroach. The 1st pair of wings is attached to mesothorax. It is leathery and protective, called Tegmina or Elytra. The 2nd pair of wings is attached to metathorax. It is membranous and is used in flight.



Each thoracic segment has one pair of legs. Because of 3-pairs of legs (6-in number), the insects are called hexapods.

Coxa

Trochanter Femur

Tibia with tibial spines Tarsus with 5-tarsomere Pretarsus Arolium (Pulvillus) Claw Fig. 7.24 : Leg of cockroach



Each leg is differentiated, from proximal to distal part, into 5-regions, i.e Coxa, Trochanter, Femur, Tibia and Tarsus. Coxa is attached to pleuron. The Tibia consists of tibial spines and is the longest part of the leg. Tarsus has 5-tarsomere. The last tarsomere has a pretarsus with arolium, and two claws.

Abdomen 

It consists of 10-segments. One pair of 15-segmented Anal Cerci arise from 10th segment and perceive ground borne vibrations.



In males there is one pair of unsegmented Anal Styles, arising from 9th segment. The abdomen in males is narrower than female.



In females the anal styles are absent and abdomen is broader. Thus sexual dimorphism is prominent in cockroach. 7 8 9

Sternum (only 9-sterna visible)

6 7

Anal cercus (from 10th)

Sternum (Only 7 sterna visible) Anal cercus (from 10th)

Anal style (from 9th) Female

Male

Abdomen of Cockroach (ventral view) Fig. 7.25 : Abdomen of Cockroach (ventral view)

DIGESTIVE SYSTEM In cockroach the alimentary canal is well differentiated and consists of 3-regions, i.e. Fore gut (Stomodaeum), Mid-gut (Mesenteron) and Hind-gut (Proctodaeum)

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BIOLOGY Salivary gland Reserviour

Pharynx

Crop

Oesophagus

Gizzard Hepatic caeca (8) Mesenteron (mid gut) Ileum

Rectum Anus Anal cercus

Fig. 7.26 : Alimentary canal canal ofofcockroach Alimentary cockroach

Check Point 1. Answer the followings: (i) Who proposed the term ‘Blatta’ for cockroach? (ii) How many segments constitute the head? (iii) What is mosaic image? (iv) What is the visual unit in compound eye of cockroach? (v) Which is the longest component of the leg? (vi) How many sterna are visible in female cockroach? (vii) What is the number of hepatic caecae? (viii) Which part of gut is called proctodaeum? (ix) What is scientific term for moulting?

Foregut 

The stomodaeum includes mouth, buccal cavity, oesophagus, crop and gizzard. It is ectodermal in origin.



There is one pair of salivary glands in cockroach. Each gland is bi-lobed. The saliva before release onto hypo-pharynx in buccal cavity, is stored in reservoir.



The crop mainly stores the food material.



The gizzard is an organ for mastication. It consists of 6-cuticular plates alternating with 6-muscular pads of longitudinal muscles.



The valve between gizzard and mid-gut is called Stomodaeal valve which allows only the fine particles of food material into mid-gut.

Mid-gut 

It is endodermal in origin. The anterior part of mid-gut consists of 4-pairs of hepatic caeca



The lining of mid-gut secretes Peritrophic membrane which protects the soft lining of mid-gut from the injury by spiniferous food. It is a temporary membrane and is removed after the food passes into hind-gut.



The digestive enzymes are secreted from hepatic caeca and the lining of mid-gut.

Hind-gut 

Like foregut it is also ectodermal in origin.



At the junction of mid-gut and hind-gut there are 60-150 blind Malpighian tubules for excretion.



The hind-gut is differentiated into ileum, colon and rectum. The rectum stores undigested waste. It also contains 6–rectal pads.

Food and digestion 

Cockroach is omnivorous and feeds upon every type of food material, like paper, leather, kitchen waste etc.



Saliva contains amylase enzyme for the digestion of starch.



The enzymes secreted from hepatic caeca and mid-gut are proteolytic, lipolytic and sucrolytic in nature.

ANIMAL TISSUES (HISTOLOGY) & COCKROACH, EARTHWORM AND FROG   

The digested food material is absorbed through mid-gut and hepatic caeca (hepatic caeca increase the surface area for absorption). In hindgut, only water and minerals are absorbed. The undigested waste passes out from rectum through the anal opening.

EXCRETORY SYSTEM 1. 2.

Primary excretory organ – Malpighian tubules Accessory excretory organs – Fat bodies, skin and reproductive organs

Malpighian tubules     

They are blind tubes between mid-gut and hindgut. Their number ranges from 60 to 150. They take excretory matter from haemocoel and pour that into the mid-gut, from where it passes outside with the faecal matter. The malpighian tubules can be compared with the septal nephridia of the earthworm as both are adapted for water conservation. The major excretory matter in cockroach is Uric acid (Uricotelic animal)

Accessory excretory organs (a)

Fat body – • It is single and multi-lobular and is present around visceral organs. • It consist of four types of cells, i.e. Trophocytes, Mycetocytes, Urate cells and Oenocytes. • The trophocytes store the reserve food material. Mycetocytes contain bacteria which are useful in synthesis of glycogen, amino acids and vitamins. The urate cells form uric acid. The oenocytes help in moulting. (The fat body is analogous to liver of the vertebrates.) (b) Skin and reproductive organs – • The excretory matter from the skin is removed through moulting (Ecdysis). The uric acid is also removed through the covering of spermatophore.

BLOOD VASCULAR SYSTEM  



The blood vascular system in cockroach is Open type, the capillaries are absent and haemocoel is well developed. The body cavity (Haemocoel) is differentiated into three sinuses due to the presence of two perforated diaphragms. The dorsal sinus, around heart, is called pericardial sinus, ventral sinus, around ventral nerve cord, is called perineural sinus while middle sinus, around visceral organs, is called peri-visceral sinus. The coelom (schizocoel) schizocoel) is reduced schizocoel in Cockroach. Since the blood pigment is absent the blood in cockroach is called haemolymph. The oxygen is carried to the tissues directly through the tracheal system.

Anterior aorta

10th Alary Muscles Heart (13-chambered) Pericardial sinus

Perivisceral sinus Dorsal & ventral diaphragm (perforated)

Ventral nerve cord (A)

Perineural sinus

11th

10th

Ostia (Valves open)

11

12th

12

13th

13th

Diastole stage

Systole stage (B)

Fig. 7.27 : (A) Blood vascular system of cockroach, (B) Systole & Diastole phases in working of heart

Ostia (Valve closed) Alary muscles

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BIOLOGY

Heart    

 

Cockroach has single, mid-dorsal and 13-chambered heart (3-chambers in thoracic region and 10 in abdominal region), present in pericardial sinus. Except last chamber, all other chambers have 1-pair of ostia each (total 12-pairs). Each ostium has valves. The heart remains suspended in the pericardial sinus with the help of Alary muscles (12-pairs). The chambers of heart are pulsating and show rhythmic diastole and systole stages. During diastole ostia open and the blood enters into the heart. During systole the ostia are closed and blood passes from posterior to anterior side through dorsal aorta. The deoxygenated blood from peri-visceral sinus and perineural sinus passes into pericardial sinus through perforated diaphragm. The function of blood (haemolymph) is the transportation of excretory and nutritive materials only. (Blood has no role in respiration / transportation of gases).

RESPIRATORY SYSTEM  

 



This system consists of tracheal tubes which are ectodermal in origin. Each tracheal tube is internally lined with cuticle, called intima which prevents collapsing of the tracheal tubes. (Both, tracheal tube of Cockroach and trachea of human have noncollapsable wall). There are 6-longitudinal tracheal ducts, 2-dorsal, 2-ventral and 2-lateral. The lateral longitudinal ducts have openings called Spiracles. The number of spiracles in cockroach is 10-pairs (2-pairs in thoracic and 8-pairs in abdominal region). The thoracic pairs of spiracles are present on pleuron between prothorax - mesothorax, and mesothorax - metathorax. Except 1st pair of abdominal Spiracles, which are present on tergum, all other 7-pairs of spiracles also lie on pleura. Each spiracle opens into a chamber called atrium. After atrium the tracheal tube ramifies into fine branches of tracheae, and then tracheoles. The tracheoles do not have intima lining.

Process of respiration (a)

Resting stage • During this stage the abdominal movements are absent and the requirement of oxygen is less. All the 10-pairs of spiracles remain open during both, inspiration and expiration. • During resting stage the tissue fluid is also drawn into tracheoles and the oxygen diffuses into the tissues after it is dissolved in tissue fluid. (b) Active stage • During this stage the abdominal movements become active and the oxygen requirement is also increased. • The tissue fluid is not drawn into the tracheoles. Oxygen passes directly to the tissue. • During inspiration all the 10-pairs of spiracles remain open, whereas during expiration all spiracles except 1st and 3rd pairs, are closed. (This means that 1st pair of thracic and 1st pair of abdominal spiracles remain always open).

NERVOUS SYSTEM All 3-types of nervous system, CNS, PNS and ANS, are present in cockroach. CNS (Central nervous system) –  It consists of a nerve ring and a ganglionated, double/paired ventral nerve cord. The nerve ring is formed by a dorsal supra-oesophageal ganglion, a ventral sub-oesophageal ganglion and a pair of circum oesophageal connectives. Each ganglion is formed by the fubion of 3-pairs of (cephalic) ganglia. The supra-oesophageal ganglion forms the brain of the cockroach.

ANIMAL TISSUES (HISTOLOGY) & COCKROACH, EARTHWORM AND FROG 

The ventral nerve cord is paired and solid but unlike earthworm, it is neither fused, nor enclosed in a common sheath. It contains 9-pairs of ganglia (3-pairs in thoracic region and 6-pairs in abdominal region). The 6th abdominal ganglion present in 7th segment, is the largest (representing many fused ganglia), and supplies nerves to the muscles of the rest of the segments.

PNS and ANS 

The nerves arising from brain and ganglia of the ventral nerve cord comprise the PNS (Peripheral nervous system). The ANS (Autonomous nervous system) is also known as Visceral nervous system or Stomogastric nervous system because it mainly supplies the anterior part of alimentary canal.



The important ganglia of ANS are Frontal ganglion, Ingluvial ganglion, on crop, and proventricular ganglion, on gizzard.

ENDOCRINE SYSTEM There are 3-types of endocrine glands in cockroach 1. Corpora cardiaca •

It is a paired gland. Each gland is present below brain on either side of the ventral nerve cord.

•

2.

The hormones produced from brain (neuro-hormones) accumulate in corpora cardiaca before they are released into the body. These hormones regulate metabolism of the body including heart beat, breathing mechanism, peristalsis etc. Corpora Allata -

•

These bodies ( 1-pair ) are attached to corpora cardiaca, close to brain, on either side of ventral nerve cord.

They produce Juvenile hormone (JH), also called as Neotinin. This hormone maintains Juvenile (nymphal/larval) characters and prevents metamorphosis, or changing of nymph into adult, or larva into pupa. Prothoracic gland -

•

3.

•

It is single and lobular gland present in the dorsal side of prothoracic segment.

•

It secretes moulting hormone, called Ecdysone. It is steroid in nature. It controls ecdysis or moulting which is primarily meant for growth. Hence, the ecdysone is also known as Growth hormone.

SENSORY ORGANS The sensory structures in cockroach include 1-pair of compound eyes, 1-pair of antenna and 1-pair of anal-cerci. The anal cerci remain in touch of ground and perceive ground-borne vibrations.

Compound eyes 

The functional unit of compound eye is Ommatidium. There are about 2000 ommatidia in each compound eye of Cockroach.



Each compound eye is differentiated into outer Diopterical region and inner Receptor region.



Each ommatidium on eye surface is represented by a hexagonal corneal facet.



Diopterical region consists of a crystalline cone, surrounded by 4-cone cells, and is separated from adjacent ommatidia by iris pigment.



The receptor region consists of a transversely striated Rhabdome, surrounded by 7-retinal cells, and is separated from adjacent ommatidia by retinal pigment.



The nerve fibres from each ommatidia form optic ganglion and pass to the brain through optic nerve.

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BIOLOGY Corneal facet Corneagen cell Iris pigment Cone cells (4) Crystalline cone

Corneal facet Diopterical region

Retinal cells (7) Rhabdome

Receptor region Optic nerve

Retinal pigment

Optic ganglion (A) (B)

Basement membrane Nerve fibre

Fig. 7.28 : (A) Compound eye in section (Diagrammatic), (B) Two-Ommatidia

Image formation

The image in case of compound eyes is formed in pieces. Such image is called Mosaic image. Each compound eye forms as many images in pieces as is the number of ommatidia before the object. In insects there are 2-types of images, i.e. Apposition image and Super position image.

Apposition image 

Check Point 1. What is the function of: (i) Elytra in cockroach (ii) Peritrophic membrane in cockroach (iii) Alary muscles (iv) Juvenile hormone in insects (v) Collaterial gland in cockroach (vi) Anal cerci in abdomen (vii) Maxillary palp (viii) Arolium in Periplanata (ix) Gizzard in cockroach (x) Sclerite in abdomen

  

Such image is formed in diurnal insects (active during day time), e.g. Butterfly, bee and housefly. As there is bright light outside, only the direct rays form the image on rhabdome. The pigmented sheath, being contractile elongate in such cases and oblique rays are prevented to form the image. Such image is sharp and clear as there is no overlapping of images.

Super position image     

Such image is formed in nocturnal insects (active at night), e.g.– Mosquito, moth etc. As there is dim-light around, the direct as well as oblique rays form the image on rhabdome The pigmented sheaths shorten to allow the oblique rays to reach the rhabdome. Since there is overlapping, the image formed is blurred. Though, the cockroach is a nocturnal insect, but it forms Apposition image because the pigmented sheath in the eye are non-contractile.

REPRODUCTIVE SYSTEM Check Point 1. How can you differentiate between? (i) Male and female cockroach (ii) Simple and compound eyes (iii) Anal style and anal cerci (iv) Females of Blatta and Periplanata (v) Superposition image and apposition image (vi) Blood and haemolymph (vii) Mushroom gland and phallic gland (viii) Seminal vesicle and spermatheca

The sexual dimorphism is prominent in cockroach, i.e. the male and female individuals can be distinguished externally. The male cockroach has a narrower abdomen and contains 1-pair of anal style arising from 9th segment. The number of sterna (sing. sternum) visible in male are 9, where as in female, only 7-sterna are visible. 1. Male reproductive system It consist of following structures 1. Testes - 1 pair 5. Male gonopore - Single 2. Vas deferens - 1 pair 6. Genital chamber - Single 3. Ejaculatory duct - Single 7. Gonapophyses - Three 4. Seminal vesicles - 1 pair 8. Reproductive glands - Mushroom glands and Conglobate (Phallic) gland • Each testis is trilobed and is present in abdomen, in segments number 4th , 5th and 6th. • Two vas deferens, arising from testes, join to form a common ejaculatory duct. • Two seminal vesicles are present at the base of ejaculatory duct and store the sperms. • The genital chamber has three phallomeres or gonapophysis to handle spermatophore and also to help in the transfer of sperms.

ANIMAL TISSUES (HISTOLOGY) & COCKROACH, EARTHWORM AND FROG The mushroom gland, also known as Uricose gland or Utricular gland, is a bunch of tubules secreting a fluid which hardens to form a Spermatophore. The conglobate gland or phallic gland is single and opens into genital chamber. It releases pheromones as sex attractant.

• •

4

5

5

6

6 Vas deferens 7

7 8

8 9

9 male genital pore (gonopore)

10

Opening of genital chamber

10

Male

Germarium

Testis

4

Mushroom gland

Conglobate gland Gonapophyses (Phallomere) (3)

4

5

5

6

6

Ovary (with 8-ovarioles)

Oviduct

Seminal vesicle

Ejaculatory duct

4

7

7

left 8 collaterial gland Female 9 gonopore Gonapophyses (6)

Genital chamber Anal style (from 9th segt.)

8 9

10

10 Female

Common oviduct (vagina)

Spermatheca (1-bilobed) Genital chamber Brood Oothecal chamber pouch

Opening of brood pouch

Reproductive systems of cockroach

Fig. 7.29 : Reproductive systems of cockroach

2.

Female reproductive system It consists of following structures – 1. Ovaries - 1 pair 3. Vagina - Single 5. Spermatheca - Single 7. Gonapophyses - 3 pairs

2. 4. 6. 8.

Oviducts - 1 pair Female gonopore - Single Brood pouch - Single Collaterial glands - 1 pair

•

Each ovary contains 8-ovarioles. Each ovariole is differentiated into distal Germarium and proximal Vitellarium. Towards vitellarium the eggs are matured and yolk deposition is completed.

•

The 2-oviducts join to form common oviduct or vagina which opens into brood pouch through single gonopore.

•

Single but bilobed spermatheca is present near female gonopore. It stores sperms after mating.

•

The Gonapophyses help in handling of the spermatophore for transferring the sperms into spermatheca and later removal of it from the (female) body.

•

Brood pouch is formed by 7th, 8th and 9th segments and is differentiated into proximal genital chamber and distal oothecal chamber.

•

Out of the two collaterial glands, the left one is larger. Both the glands open into brood pouch. The secretion of collaterial glands forms ootheca.

Breeding season and fertilization 

In cockroach the breeding season is March to September.



Spermatophore is formed from the secretion of mushroom gland around sperms in ejaculatory duct. The lining of ejaculatory duct produces second covering around spermatophore. Later, when the spermatophore passes out from the male’s body the secretion of conglobate gland forms third covering around it.



8-eggs are released from each ovary, one from each ovariole, and in all, 16-eggs are released into the genital chamber.



During mating, the spermatophore, with the help of male gonapophyses is transferred into female body. The gonapophyses of the female body fix up the spermatophore against the spermathecal opening. All sperms from spermatophore are transferred into the spermatheca. The empty spermatophore is thrown out by female gonapophyses.

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BIOLOGY 

The fertilization of the eggs occurs in genital chamber by the sperms released from spermatheca.

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The secretion of collaterial glands forms ootheca around the fertilized eggs. All eggs are arranged in 2-rows (of 8-eggs each). The ootheca formation occurs in oothecal chamber of brood pouch.

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This ootheca is placed by female cockroach in dark and warm region. The placement of ootheca is called oviposition.

Development 

Cockroach is a Paurometabola insect, showing gradual metamorphosis.



The development stages are nymphs (16-in number) which are released from ootheca.

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The nymphs are immature, smaller in size and wingless. They undergo 5-6 moultings (each stage called Stadium) to form adult.

*EARTHWORM Taxonomic position Phylum Annelida Class Oligochaeta Order Opisthopora/Haplotaxida Genus Pheretima Species posthuma  It is metamerically segmented with 100-120 segments (metameres), each separated by inter segmental groove. The number of segments remains fixed throughout life, i.e. neither new segments are added, nor the old ones are removed.  It is burrowing (fossorial).  The skin is light brown due to the presence of Porphyrin pigment which is derived from chlorophyll, taken by the young animal with the soil.  The dorsal side of the body can be distinguished by the presence of a prominent dorsal blood vessel. The ventral side contains two pairs of prominent genital papillae, one pair in each segment number, 17th and 19th.  The first segment, called Peristomium, bears mouth on the ventral side. The hood like projection of peristomium is called prostomium.  The male genital apertures (gonopores) are two (one pair), present on ventral side of 18th segment.  Female genital aperture is single and is present Prostomium st in mid-ventral side of 14th segment. 1 Mouth (1 )  Spermathecal pores are four pairs and are present Peristomium 3 in inter-segmental grooves of segments 5/6, 6/7, 5 7/8 and 8/9. 7 Spermathecal pores  The anal opening is present in the last segment. 9

(5/6, 6/7, 7/8, 8/9)

The body of the earthworm can be differentiated into 11 Setae 3-regions – 13 1. Pre-clitellar region (1st to 13th segments) Female genital pore (single) 15 (14) 2. Clitellar region (14th, 15th and 16th segments). Clitellum (14, 15, 16) th 3. Post-clitellar region (17 to last segment). 17 Genital papillae (17,19) (As the number of total segments ranges from 100 19 Male genital pore (paired) to 120, the number in post-clitellar region may be 21 (18) different in different earthworms. The number of segments in preclitellar region and clitellar Antero-ventral view of Pheretima posthuma region is fixed xed.) Fig. 7.30 * Study of Earthworm is not included in NEET Syllabus.

ANIMAL TISSUES (HISTOLOGY) & COCKROACH, EARTHWORM AND FROG

295

Septae     

They are the partitions between adjacent segments in inter-segmental grooves. The septae are absent from segments 1st to 4th. The presence of continuous-coelomic fluid in these segments make them turgid, to help in burrowing. Septae are also absent between 9th and 10th segments. In rest of the segments ( up to 14th ) the septae are non-porous. From 14 th / 15th segments all the septae are porous and coelomic fluid, acting as hydrostatic skeleton, is interconnected.

BODY AND COELOM   

Bodywall consist of 4-layers, i.e. cuticle, epidermis, circular muscles and longitudinal muscles. Earthworm is Eucoelomate, having schizocoel, lined with somatic/parietal mesoderm on the outside and visceral/splanchnic mesoderm in the inner side. Coelom contains coelomic fluid, acting as hydrostatic skeleton. This fluid oozes out from the body through dorsal pores in inter-segmental grooves, one per segment, from 12/13th to the last of the body.

LOCOMOTION  

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 

It is carried out by body wall musculature (circular muscles and longitudinal muscles). The setae are chitinous structure present in setigerous sac and are produced from formative cells. They are embedded in the body wall and can move with the help of protractor and retractor muscles. Coelomic fluid, forming hydrostatic skeleton, and the setae help in locomotion. To begin with, the circular muscle of anterior part contract and the part increases in length. It is followed with the contraction of longitudinal muscles and the diameter of the region increases. To prevent retraction of the anterior segments the setae are inserted into the ground. This process of alternate contraction of circular and longitudinal muscles extends posteriorly and the whole body moves. This process of locomotion, called ‘Thinning and thickening process’ was described by Gray and Lissman.

NUTRITION  

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Earthworm is soilivorous/detritivorous or omnivorous. The alimentary canal is complete and highly specialized. It consists of following parts – 1. Mouth and buccal cavity 2. Pharynx 3. Oesophagus 4. Gizzard 5. Stomach 6. Intestine 7. Rectum 8. Anus The pharynx (segments 3rd and 4th) is suctorial and is differentiated into two chambers, dorsal chamber and ventral chamber. Pharyngeal gland or salivary gland is present in the dorsal side of pharynx. Salivary glands secrete saliva into the dorsal chamber. The chromophil cells of pharyngeal gland/salivary gland are analogous to the chief cells of vertebrate stomach, as they secrete proteolytic enzymes, just like pepsin, which digest food in acidic medium in the presence of humus acid of the soil. Gizzard (segment 8th – 9th) is a masticatory organ and helps in cutting down the food material due to muscular movements. It has cuticular lining. The longitudinal muscles in gizzard are absent. Stomach extends from 9th to 14th segment. In earthworms, other than Pheretima posthuma, there are calciferous glands in stomach to neutralize the acidic medium. Intestine is the longest and widest part of the alimentary canal and extends from 15th segment to the last. It is meant for digestion and absorption of the food material. One pair of intestinal caeca arise from 26th segment and extend forward up to 22/23rd segment. These caeca, also called hepatic caeca, secrete amylase for carbohydrate (starch) digestion. The other enzymes secreted from intestinal lining are cellulase, chitinase, lipase, trypsin etc.

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30

Peristomium (1st segment) Mouth rd

th

Pharynx (3 & 4 ) oesophagus th

th

gizzard (8 & 9 ) stomach

th

Intestine (From 15 )

Intestinal or Hepatic caeca th rd (26 to 22/23 ) Typhlosole

Alimentary canal Fig. 7.31

296

BIOLOGY Connecting Concepts

T Typhlosole , is the dorsal ingrowth in the form of a fold in the major part of intestine and increases surface area for absorption. It is analogous to the villi of the ileum of vertebrate’s intestine.



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Intestine is differentiated into 3-parts, namely 1. Pre-typhlosolar region (15th to 26th segment) 2. Typhlosolar region (27th to leaving last 25 segments) 3. Post-typhlosolar region (last 25 segments) The post typhlosolar region (last 25 segments), also known as rectum, is for the storage of undigested waste, which is removed from the gut in the form of ball-shaped castings.

RESPIRATION   

EXCRETORY SYSTEM

Connecting Concepts In the larvae of polychaetes the nephridia are simple, called protonephridia, and don’t have nephrostome. In earthworm they are called metanephridia and contain Nephrostome also. In integumentary and pharyngeal nephridia, the nephrostome has become secondarily absent. The septal nephridia are truly metanephridia.

Earthworm respires through moist skin (cutaneous respiration). The skin is kept moist by coelomic fluid oozing out through dorsal pores. Because of the cylindrical shape the ‘surface area to volume ratio’ is higher in earthworm. There is no specialized respiratory or breathing structure in the body.



The excretory structures in earthworm are nephridia (metanephridia). They are ectodermal in origin and are of 3-types – 1. Integumentary Nephridia 2. Pharyngeal Nephridia 3. Septal Nephridia

1. Integumentary Nephridia • •

• • •

They are present in the skin/integument of segments number 3rd to last. They are maximum in clitellar region (14, 15 and 16th segments ). The term ‘Forest of nephridia’ is used for these nephridia in clitellar region, as their number ranges from 2000-2500 per segment. The number of these nephridia in other segments is 200-250 per segment. They are the simplest nephridia and do not have nephrostome. The excretory matter is taken from blood and is poured outside the body through nephridiopores. That is why such nephridia are called Exonephric nephridia or Exteronephric nephridia.

2. Pharyngeal Nephridia • • 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

Pharynx Pharyngenal nephridia Duct of Ph. nephridia

Integumentary Nephridia Clitellum Septal Excretory canal Septal Nephridia Supra intestinal duct

Fig. 7.32structures : Excretory structures in Excretory in Pheretima Pheretima

• • • • •

They are present near pharynx in segments number 4th, 5th and 6th only. There is one pair of tuft/bunch per segment. Each tuft has about 100 nephridia (200 nephridia per segment). Out of 3-types of nephridia the pharyngeal nephridia are minimum in number. They too lack nephrostome and are, therefore, simple in structure. Like integumentary nephridia they also take excretory matter from the blood. These nephridia pour the excretory matter into pharynx through nephridial ducts. Such nephridia are called Endonephric nephridia or Enteronephric nephridia.

3. Septal Nephridia • • • • • •

They are attached to intersegmental septae, from 15/16th septa, to the last. They are called typical nephridia or Holonephridia as they are complete and contain nephrostome. The number of these nephridia ranges from 80-100 per segment. They collect excretory matter from blood as well as coelom, from latter through nephrostome. The excretory matter is poured through septal excretory canal and supra intestinal duct, into intestine. Such nephridia are also known as Endonephric nephridia or Enteronephric nephridia since the excretory matter goes outside through the gut.

ANIMAL TISSUES (HISTOLOGY) & COCKROACH, EARTHWORM AND FROG (Both pharyngeal and septal nephridia pour the excretory product into gut for water absorption, and are thus adapted for water conservation.) Each septal nephridium consists of following parts – 1. Nephrostome 2. Twisted lobe (proximal and distal limb) 3. Straight lobe 4. Terminal duct The route of excretory product through septal nephridia is – Nephrostome → proximal limb → distal limb → straight lobe → distal limb → proximal limb → terminal duct The excretory product in earthworm is urea (ureotelic). In rains, due to plenty of water, the major excretory product becomes ammonia. The chloragogen cells, present in the visceral mesoderm of gut and coelomic fluid of the body, synthesize urea and other excretory materials like chloragogue formed by the metabolism of haem. The chloragogen cells also store reserve food material, and are, therefore, comparable(analogous) to vertebrate liver.

BLOOD VASCULAR SYSTEM (BVS)      

BVS in earthworm is closed type. Hemoglobin is dissolved in plasma and RBCs are absent. WBCs or phagocytic cells are present. The blood is synthesized in blood glands in segments 4th, 5th and 6th The pharyngeal nephridia and blood glands occur together in the same segments, i.e., 4th, 5th and 6th. The lymph glands which produce phagocytic cells and release them into coelomic fluid, are 1 pair per segment (from 26th to last). They are dorso-lateral in position. The blood vascular system in earthworm can be studied in 2-parts-

1. BVS in first 13-Segments It consist of following prominent structures (i) Dorsal blood vessel (DBV). (ii) Supra-oesophageal blood vessel (SOBV) (iii) Ventral blood vessel (VBV) (iv) Lateral Oesophageal blood vessel (LOBV) (v) Hearts (vi) Anterior loops. (i) Dorsal Blood Vessel • It is single or unpaired and prominent blood vessel in the mid-dorsal side of the body. • It is distributive in nature and supplies blood to the anterior part of the gut, i.e. buccal cavity, pharynx oesophagus, stomach and gizzard. • It has one pair of valve per segment and is comparable to the veins of vertebrates or heart of cockroach. • The direction of blood-flow is from posterior to anterior side. • It is connected to ventral blood vessel through two pairs of false and two pairs of true hearts. (ii) Supra-Oesophageal Blood Vessel • It is also single or unpaired blood vessel, present in segments number 9th to 13th only. • It is collective in nature and collects the blood from anterior part of alimentary canal. • The valves are absent in this blood vessel. • It receives blood from LOBV through anterior loops. (iii) Ventral Blood Vessel • It is also single or unpaired vessel present in the mid-ventral side of the body. • It is distributive in nature. • It supplies blood to nephridia, body-wall, septae and reproductive organs. • The direction of blood flow is from anterior to posterior side. • The valves are absent. • It receives blood from dorsal blood vessel through false and true hearts.

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BIOLOGY (iv)

Lateral Oesophageal Blood Vessel • It is paired and lateral in position. • It is collective in nature, and collects the blood from skin, excretory organs, reproductive organs etc. • The direction of blood flow is from anterior to posterior side. • Valves are absent. False Hearts

6

7

8

True Hearts

9

Ant. Loops 10 11

12

13

Intestinal blood vessels 14

15

16

17

DBV

DBV

–CV

SOBV

INTE STINE LOBV LOBV VBL

VBV SNBV

Blood Vascular system in Pheretima (DBV- Dorsal Blood vessel, VBV-Ventral blood vessel, SOBV-Supraoesophageal Blood Vessel, LOBV - Lateral oesophageal blood vessel, CV- Commissural vessel)

Fig. 7.33 : Blood Vascular System

(v)

1.

2.

(vi)

Hearts• There are 4-pairs of hearts (8 in number) in earthworm. • They are of 2-types – Lateral hearts • They are also known as false hearts. • They are 2-pairs in number, 1 pair each in segments, 7th and 9th. • They connect dorsal blood vessel to ventral blood vessel. • The direction of blood blow is from dorsal to ventral side. • There are 4-pairs of valves per lateral heart. Lateral oesophageal hearts • They are also known as true hearts. • They are also 2-pairs in number, 1 pair each in segments, 12th and 13th. • They connect dorsal blood vessel and supra oesophageal blood vessel to ventral blood vessel. • Direction of blood flow is from dorsal to ventral side. • Each heart has 3-pair of valves, 1 pair at each opening of dorsal/ventral and supra oesophageal blood vessels. Anterior loops • There are 2-pairs of anterior loops ( 4 in number ). • They are non-pulsating in nature and are present in segments, 10th and 11th. • They connect supra-oesophageal blood vessel to lateral oesophageal blood vessel. • The direction of blood flow is from ventral to dorsal side (LOBV to SOBV) • Valves are absent.

2. BVS After 13-Segments egments The blood vascular system from 14th to the last segment consists of following important vessels. (i) Dorsal blood vessel (DBV) (ii) Ventral blood vessel (VBV) (iii) Subneural blood vessel (SNBV) (iv) Commissural vessels (v) Intestinal vessels

ANIMAL TISSUES (HISTOLOGY) & COCKROACH, EARTHWORM AND FROG (i)

Dorsal blood vessel • After 13-segments, it becomes collective in nature and collects blood from alimentary canal, excretory organs and reproductive organs. (Since DBV collects blood from about 100 segments (14th to last) it is mainly collective in nature). • The supra-oesophageal blood vessel, collecting blood from anterior part of the gut, is absent after 13th segment. (ii) Ventral blood vessel • It is same throughout the body. (iii) Sub-neural blood vessel• Two LOBV unite after 13th segment to form single blood vessel which runs posteriorly below the ventral nerve cord, and is so called sub-neural blood vessel. • The sub-neural blood vessel is connected to dorsal blood vessel through commissural vessels. (iv) Commissural vessels • They are 2 (1 pair) per segment and are present after 15th segment to the last. • They connect dorsal blood vessel to sub-neural blood vessel. • The blood flow is from ventral to dorsal side. (v) Intestinal blood vessels • They are 2-pairs per segment. • They are collective in nature and pour the blood into dorsal blood vessel.

NERVOUS SYSTEM Earthworm contains central nervous system (CNS), peripheral nervous system (PNS) as well as autonomous nervous system (ANS)  The central nervous system consists of a nerve ring and a paired ventral nerve cord.  The nerve ring is formed by supra-pharyngeal ganglia, circum-pharyngeal connectives and subpharyngeal ganglia. The ring is present around pharynx.  Supra pharyngeal ganglia form the brain of the earthworm.  The ventral nerve cord is paired but fused to appear as single, and is enclosed in a common sheath. It is ganglionated, having 1-pair of ganglia (fused) per segment.  Above ventral nerve cord there are 4-giant nerve fibers, having greater diameter, for conducting the impulses at a faster pace. Sensory Structures –  The Sensory structures in skin are thigmoreceptors.  The dorsal side of anterior segments, particularly peristomium and prostomium, contains photoreceptor cells. Each photoreceptor cell has a lens like structure, called phaosome. These cells do not form the image but detect the presence of light.

REPRODUCTIVE SYSTEM  

Earthworm is bisexual (monoecious) or hermaphrodite. Both male and female reproductive systems are present in antero-ventral side of the body.

Male Reproductive System It consists of following parts 1. Testes - 2-pairs (10th and 11th segments) 2. Testes sac - 2 (10th and 11th segments) 3. Vas deferens - 2-pairs. 4. Seminal vesicle - 2-pairs (11th and 12th segments) 5. Prostate gland - 1-pair (17th to 20th segments) 6. Genital aperture - 1 pair (18th segment)  Testes are present in the testes sac. They produce spermatocytes which enter into seminal vesicles. The maturation of sperms occurs in seminal vesicles (not testes).

299

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BIOLOGY Sperms from seminal vesicle pass into vas deferens through spermatic funnel. The sperms with the secretion of prostate gland are released through male genital apertures as spermatic fluid. The accessory glands, for adhesive secretion, open into genital papillae in segments number 17th and 19th

  1 2 3 4 5 6 7 8 9 10 11 12 13

 Spermathecae (6, 7, 8 & 9)

Testes Sac (10 & 11)

It consists of following parts Ovaries - 1-pair (13th segment) Oviducts - 1-pair 3. genital aperture - Single (14th segment) 4. Spermathecae- 4 pairs (6th, 7th, 8th and 9th segments)  Each ovary consists of a number of ovarioles, and is attached to the septa of 12th/13th segment.  The eggs pass through oviducal funnel and oviduct, and are released through single genital aperture in 14th segment.  The spermathecae are differentiated into outer ampulla and inner diverticulum, and open in intersegmental groove in 5th/6th , 6th/7th, 7th/8th and 8th/9th segments. In earthworm ((Pheretima) the sperms, of the other earthworm, are stored in the diverticulum part of the spermathecae.

Seminal vesicle (11 & 12) 1. Ovary (13) 2. Female genital pore (14)

14 15 16 17 18 19

Female Reproductive System

Testes (10 & 11)

Vas deferentia Prostate gland (17 - 20) Male genital pore (18) Genital papillae (17, 19)

20 21 22

Reproductive system in Pheretima

Fig. 7.34

Breeding and fertilization    

  

It occurs before dawn, during rainy season. Earthworm is protandrous and self fertilization is absent. Fertilization is cross and reciprocal. The two earthworms get attached in the antero-ventral side with the help of genital papillae. The male genital apertures of one earthworm face the first pair of spermathecal opening of 5th/6th segment of the other earthworm. During mating the sperms of one earthworm are transferred into the diverticulum of spermathecae of the other earthworm, and vice-versa. The eggs are released through female genital aperture in 14th segment (anterior Clitellar region). The epithelium of clitellum secretes cocoon. This cocoon contains unfertilized eggs. 18th

5/6

5/6

Eggs 5/6

5/6

Sperms

Cocoon with fertilized eggs

Fig. 7.35 : Clitellum secretes cocoon

•

•

Now earthworm wriggles backwardly and comes out of the cocoon through its anterior end. When the cocoon comes around the openings of spermathecae, the sperms are released over the eggs and the eggs get fertilized in the cocoon. Thus, the fertilization is external but in cocoon. The epidermal glands also secrete albumin which is stored in the cocoon as a reserve food material for developing embryo.

ANIMAL TISSUES (HISTOLOGY) & COCKROACH, EARTHWORM AND FROG

Development In earthworm the development is direct, i.e. without larva formation. Out of 2 - 20, usually 4 - embryos are matured in the cocoon, and rest are used as food.

 

Economic Importance Earliest use of earthworm is in Unani and Ayurvedic medicines for the treatment of gout. Earthworms are also used as a bait for fishing. They are natural ploughmen and make the soil porous. They enrich the soil (increase the fertility) by adding excretory and faecal matter. The ‘vermicompost’ is in high demand, these days.

    

* FROG Taxonomic position Phylum Chordata Class Amphibia Order Anura Genus Rana Species tigrina  Rana tigrina is commonly called as Indian Bull-frog.  It is amphibious, and can be found in ponds/shallow water bodies, and in terrestrial conditions. Its close relative, Toad ((Bufo melanostictus) is largely terrestrial.  It is cold blooded or Poikilothermic and shows summer-sleep (Aestivation) and winter-sleep (Hibernation) in extreme temperatures.  Its body colouration shows camouflage. (Its colour changing ability is called Metachrosis)  It is insectivorous/carnivorous.

External Morphology The body of the frog is streamlined, well adapted for swimming, leaping and burrowing. It skins is slimy, moist without exoskeleton or scales. Skin contains mucus and poison glands, the latter are concentrated on shoulders. The chromatophores in the skin help in camouflage. Eyes are dorso-laterally placed on head. Frog has 3-eye lids, i.e. upper eye-lid, lower eye-lid and third eye-lid (Nictitating membrane), the later covering the eye-ball during swimming. External ear is absent in frog. The tympanum/ear drum is present near the eyes. The body of the frog is divisible into head and trunk. The neck is absent. The trunk has 1-pair of shorter fore limbs and 1-pair of longer hind limbs. Each hand has 4-fingers (digits) whereas each foot has 5-toes (digits). (The thumb, pollex pollex, or the first finger in hand is absent in frog.)

    

Internal Morphology (Anatomy) and physiology (a)

(b)

Digestive system • Due to carnivorous nature, the alimentary canal of frog is short. The posterior most part of the gut is cloaca. Urine also passes through cloacal opening. • Due to absence of Uvula, the buccal cavity and pharynx are not differentiated. The buccopharynx contains numerous maxillary teeth. The teeth in frog are Homodont (similar type), Acrodont (fused with the Jaw-bones) and Polyphyodont (many sets of teeth). The teeth are, however, absent in lower-jaw. Besides upper-jaw, the teeth are also present in vomer bone of olfactory capsule, in the roof of bucco-pharynx. The teeth in frog are not used for cutting the food material, but are used for preventing the escape of the prey. The tongue in frog is bifid at the tip and is free behind. It is used for capturing prey (insects). Respiratory system • Frog respires through skin (Cutaneous respiration), bucco-pharyngeal lining and through lungs (Pulmonary respiration). During aestivation and hibernation the only mode of respiration is cutaneous.

* Study of Earthworm is not included in NEET Syllabus.

301

302

BIOLOGY •

(c)

The lungs are hollow, non-lobular and positive pressure type. The pulmonary respiration has 3-phases, i.e. Aspiration, Inspiration and Expiration. During aspiration sternohyal muscles of lower-jaw contract and air through nostrils is filled into bucco-pharynx. During inspiration the lower-jaw is raised (due to contraction of petrohyal muscles) and nostrils are closed. The air is forced into the lungs (+ve pressure lungs). In expiration the air comes out of the body through nostrils.

Blood vascular system •

In frog BVS is closed type and has double circulation, though not as efficient as in birds and mammals.

•

The heart is 3-chambered (2-atria and 1-ventricle). The dorsal side of the heart has a triangular structure, called Sinus venosus which receives deoxygenated blood from 2-precavals and 1-postcaval. It pours the blood into right atrium. On the ventral side of the heart there is a prominent Structure, called Conus arteriosus which arises from the ventricle. Conus arteriosus is differentiated into proximal Pylangium (bulbous arteriosus) and distal Synangium (ventral aorta). The Pylangium contains cardiac muscles and is the part of the heart. It also contains a fold-like Spiral valve which divides it into Rt- ventral chamber, Cavum aorticum, and Lt-dorsal chamber, Cavum Pulmocutaneum. Each branch of ventral aorta contains 3-arches i.e. Pulmocutaneous (Dorsal), Systemic (middle) and common carotid (ventral).

•

The SA node is present in the wall of sinus venosus and not in the right atrium, as in mammals.

•

As there is single ventricle (inter-ventricular septum absent), the bicuspid and tricuspid valves are not differentiated and blood of the 2-atria is mixed in ventricle.

•

The AV node and Bundle of His are absent in frog.

•

There are 2-types of portal systems in the body of frog, i.e. Hepatic portal system (between gut and liver) and Renal portal system (between posterior abdominal parts and kidney). carotid (ventral) systemic

pulmonary veins aortic trunks

pulmocutaneous (dorsal)

anterior vena cavae or precaval

VA

right atrium

right atrium spiral valve

BA

conus arteriosus

semilunar valves

sinus venosus

Atrioventricular valves

ventricle

ventricle posterior vena cavae or post caval DORSAL

left atrium

VENTRAL

FRONTAL SECTION

Fig. 7.36 : Heart of Frog (BA-Bulbous arteriosus or Pylangium, VA-Ventral aorta or Synangium)

Renal portal System : 

The femoral vein, arising from outer thigh region, after entering abdomen, bifurcates to form outer renal portal vein and inner pelvic vein.



The renal portal vein terminates into kidney whereas the pelvic veins of two sides join to form Anterior Abdominal Vein. The anterior abdominal vein finally terminates into liver.



The Sciatic vein that arises from inner thigh region joins renal portal vein and pours its blood into that.

ANIMAL TISSUES (HISTOLOGY) & COCKROACH, EARTHWORM AND FROG LIVER Anterior abdominal vein Left Kidney

Right kidney

Pelvic vein Renal portal vein Sciatic vein Femoral vein

Fig. 7.37 : Renal portal system

(d)

(e)

Nervous system • Frog has all 3-types of nervous system, i.e. CNS (brain and spinal cord), PNS (Cranial nerves and spinal nerves) and ANS (SNS and PSNS). • The cranial and spinal nerves in frog are 10-pairs each. However, in Rana tigrina the number of spinal nerves is 9-pairs. • In brain the cerebral hemispheres are less developed than in the mammals. The corpus callosum, connecting two cerebral hemisphere internally in mammals, is absent in frog. • The mid brain consist of 2 optic lobes (Corpora bigemina). Both lobes are hollow with optocoel. • Hind brain consists of cerebellum and medulla oblongata. The pons is absent in frog. Sensory organs • The eye-ball in frog is cartilaginous. The colour vision is lacking due to absence of cones in retina. In place of lacrymal and meibomian glands, there are Harderian glands in frog. • The sensory part for hearing in the internal ear of frog is Pars basilaris & Pars lagena. The Cochlea and Organ of Corti are absent. The round window (Fenestra rotundus) between middle and internal ear is also absent. • In olfactory capsule the Septo-maxillary bone is the smallest bone of the frog’s body.

ENDOSKELETON Skull : It consists of 2-parts. (i) Neurocranium (ii) Splanchnocranium (i) Neurocranium : It forms Cranium (enclosing brain) and sensory capsules (enclosing sense organs). (A) Cranium - It forms brain-box and is mainly differentiated into (i) Occipital region (ii) Parietal region (iii) Frontal region premaxillary teeth maxillary teeth cartilaginous nasal capsule or olfactory chamber

premaxilla

septomaxillary external naris nasal Diamond shaped area of sphenethmoid

internal nairs vormer vomerine teeth palatine foramen for venerve parasphenoid

maxilla frontoparitals orbital fossa

pterygoid

pterygoid

foramina for II nerve

quadratojugal

squamosal

VI nerve

prootic

quadrate cartilage

auditory capsule

fenestra ovalis exoccipital

occipital condyle

(A)

foramen magnum

exoccipital

occipital condyles

(B)

Fig. 7.38 : (A) Skull (Dorsal, view), (B) Shull (Ventral view)

V & VII nerves quadratojugal columella fenestra ovalis

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BIOLOGY (i)

Occipital region - It is formed by 2-exoccipitals enclosing Foramen Magnum. Each exoccipital has 1-occipital condyle (skull - Dicondylic).

(ii) Frontal & Parietal regions are fused to form Fronto-Parietal bone (dorsally) and Parasphenoid (ventrally). The parasphenoid is unpaired (single) and inverted ‘T’shaped bone. In the middle of two bones, i.e. Frontoparietal and parasphenoid, there is another unpaired bone in the anterior side; it is sphenethmoid, with only a diamondshaped area visible. (B) Sensory Capsules - It includes optic capsule, auditory capsule and olfactory capsule. (i)

Optic capsule - No specific bone.

(ii) Auditory capsule - It includes Columela auris (in the middle ear) and prootic (around internal ear or membranous labyrinth) (iii) Olfactory capsule - It consists of Nasal (dorsal), vomer (ventral), having vomerine teeth, and Septomaxillary (anterior). (The septomaxillary is the smallest bone in the Frog’s body). (ii)

Splanchnocranium - It forms visceral skeleton, i.e. lower jaw, upper jaw, suspensorium and Hyoid apparatus. (A) Upper Jaw Each half (ramus) of upper jaw consists of 6-bones, 3-in outer margin ((premaxilla, maxilla and quadratojugal), 2-in inner margin ((Palatine quadratojugal), Palatine and pterygoid) pterygoid and 1-in dorsal side (squamosal). squamosal squamosal). The premaxilla and Maxilla (bones) contain teeth ((Acrodont, Homodont and Polyphyodont type). Quadratojugal is comma-shaped (Quadrate-a cartilage and jugal-a bone), the palatine is rod-shaped and pterygoid is tri-radiate. The squamosal is also tri-radiate but hammershaped.

mentomeckelian

dentary angulosplenial

(B) Lower jaw Each half (ramus) of lower jaw consists of 3-bones ((Angulosplenial, Dentary and Mentomeckelian) and 1-cartilage (Meckel’s cartilage). The two halves are attached at Mentomeckelian. The teeth in lower jaw of frog are absent.

coronary process articular facet for quadrate

The lower jaw (through Angulosplenial) articulates with quadratojugal and forms ‘Autostylic type’ of suspensorium. The quadratojugal is called ‘Bone of suspensorium’.

Fig. 7.39 : Lower jaw

(The occipitals, sphenethmoid, Mentomeckelian and auditory capsule - bones in frog are cartilaginous or replacing bones, and the rest of the skull bones are investing or dermal bones.) (C) Hyoid apparatus It consists of ‘Body of hyoid’, Anterior cornua, posterior cornua and Alar processes. The whole hyoid apparatus, except post cornua, is cartilaginous. The post cornua are bony (replacing bone) and guard ‘glottis’ opening. VERTEBRAL COLUMN : Total number of vertebrae = 10 (i)

Cervical = 1 (1st)

(ii)

Thoracic = 6 (2nd to 7th)

(iii) Lumber = 1 (8th)

(iv)

Sacral = 1 (9th)

(v)

Caudal = 1 (10th)

1st (Atlas) - It is ring shaped with reduced centrum. The prezygapophyses and transverse processes are absent. Ant. side (towards skull) has two facets for occipital condyles (skull - Dicondylic) 2nd to 7th (Typical vertebrae) - Their centrum is procoelous, pre and post zygapophyses present, and the transverse processes are well developed. 8th vertebrum - It has amphicoelous centrum. The rest features are similar to typical vertebrum. 9th Vertebrum - Its has acoelous Centrum with double convexity on post side. 10th (Urostyle) - Its Centrum is rod-shaped. It is sword-shaped (formed by the fusion of several caudal vertebrae of tadpole). It is the longest vertebrum with 2-concavity on anterior side for fitting with 2-convexity of 9th vertebrum.

ANIMAL TISSUES (HISTOLOGY) & COCKROACH, EARTHWORM AND FROG Sternum : It consists of 4-components. From anterior to post side, they are - Episternum (cartilaginous), Omosternum (inverted ‘Y’-shaped and bony), Mesosternum (rod-shaped and bony) and xiphisternum (cartilage). GIRDLES : Pectoral girdle : It is arc shaped and mainly consists of replacing bones. The two halves of pectoral girdle are fused with sternum to protectt lungs and heart ((Remember that ribs are absent in Frog).

clavicle suprascapula scapula

episternum omosternum precoracoid

coracoid glenoid cavity epicoracoid

mesosternum xiphisternum

Fig. 7.40 : Pectoral girdle and sternum

Each half of pectoral girdle consists of (i) Coracoid (ii) Scapula - The universal bone of pectoral girdle, with acromian process. (iii) Glenoid cavity (between coracoid and scapula) for articulation of head of Humerus. (iv) Clavicle - Collar bone (an investing bone) (v) Suprascapula - a calcified cartilage Pelvic girdle : • Each half (called Innominate bone) consists of Ilium (the longest), Ischium and Pubis (The pubis is the smallest component, and is of caleified cartilage). • Acetabulum cavity (for articulation of head of Femur) is formed by the participation of all the 3-bones. • Obturator foraman is absent. facet for 9th vertebra ilium iliac crest

articular surface for urostyle

iliac crest

acetabulum

ischium

acetabulum

ischium

(A)

ilium

(B) Fig. 7.41 : (A) Pelvic girdle, (B) Innominate bone

pubis

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BIOLOGY

Limb Bones (1)

Fore Limbs : Each fore-limb has 23-bones (i) Humerus (1) - characterized by deltoid ridge. (ii) Radio-ulna (1) - the two-bones fused. Ulna characterized by Olecranon process. (iii) Carpals (6) - arranged in 2-rows of 3-each. (iv) Metacarpals (5) (v) Phalanges (10) - Thumb/pollex absent, phalangeal formula = 02233

(2)

Hind Limbs : Each hind limb has 25 bones (i)

Femur (1) - stretched ‘S’-shaped, Trochanter absent.

(ii) Tibio-fibula (1) - Longest bone of Frog’s body, with nutrient foramen in the middle. Tibia has a small cnemial crest in the anterior side. (iii) Tarsals (4) - Arranged in 2-rows. Proximal tarsals well developed and also called as Astragalus or Tibiale (thin & curved) and Calcanium or Fibulare (thick and straight). (iv) Metatarsals (5) (v)

Phalanges (14) - Hallux or great toe present, phalangeal formula = 22343 (ring-finger is the longest one). Regarding joints in Frog, the ‘Pivotal joint’ is absent (since axis vertebrum/odontoid process is lacking).

maxilla orbital fossa frontoparitals

premaxillae nasal squamosal atlas phalanges metacarpals carpals radio-ulna

suprascapula

humerus

typical vertebrae 8th vertebra 9th vertebra urostyle

femur

tibio-fioula calcaneum astragalus

calcar distal tarsals metatarsals phalanges

Fig. 7.42 : Endoskeleton (Dorsal view)

ANIMAL TISSUES (HISTOLOGY) & COCKROACH, EARTHWORM AND FROG (g)

(i)

Excretory system 

The kidneys in frog are mesonephros. Such kidney is not differentiated into cortex and medulla.



Each kidney has 4-5 pairs of renal artery and veins.



The nephrons or uriniferous tubules are not differentiated into PCT, DCT and Henle’s loop.



The major excretory product in frog is urea (Ureotelic).

Reproductive system 

The sexual dimorphism in frog is prominent during breeding season. The male frog differs from female frog in the following features. 1.

Male frog has nauptial pad at the base of first finger (actually second finger, as pollex thumb is absent)

2.

Males have vocal sacs for amplification of sound.

3.

The colour pattern of the male is also different from the female body. Ostium Fat bodies

Fat body

Oviduct Vasa efferentia Left testis Adrenal gland Kidney

Right testis

Kidney

Ovary

Adrenal gland Ureter

Urinogenital duct Rectum

Urinary bladder

Rectum

Ovisac

Urinary bladder Cloaca

Cloaca Cloacal aperture

Cloacal aperture

Fig. 7.43 : Urinogenital system in Frog. A- Male, B- Female

(i)

(ii)

Male reproductive system • The testes are attached to kidney through fold of peritoneum, called mesorchium. • The sperms from testes pass through vas efferentia (10-12 in number) and are released into Bidder’s canal, a collecting duct of the kidney. (It is because, the vas-deferens is absent in frog). • The mesonephric duct (or Wolffian duct) of kidney is, therefore, also known as urino-genital duct. Faecal matter, urine and sperms, all are released through cloacal opening. Female reproductive system • The ovaries are also close to kidney, but unlike testes, are not functionally connected to it. The oviducts open separately into cloaca.

Development 



The Frog is spontaneous or seasonal ovulator, i.e. the Ovulation occurs according to the season. (Rabbit is Induced or Reflex ovulator, i.e. copulation induces ovulation). The eggs (2000 - 4000) are laid in spawn. The eggs in frog are mesolecithal and telolecithal. The animal hemisphere of the egg is pigmented due to presence of melanin and shows camouflage. The eggs are at secondary oocyte stage with one polar body. Each egg is covered by an inner non-living, vitelline membrane and outer jelly, the latter secreted from oviducts.

307

308

BIOLOGY 

The jelly is protective (shock absorber), distasteful, adhesive and non-conductor of heat. It is light in weight and keeps the eggs floating on water surface to ensure them sufficient oxygen and sunlight. The jelly also contains ‘Fertilizin’ for the attachment of sperms.



The copulation (without copulatory organ in male) is false and is called Amplexus.



The Fertilization is external (in water). After fertilization, due to movement of melanin particles there develops a ‘Gray crescent’, opposite to the sperm entrance point. The 1st cleavage occurs through the middle of Gray crescent to establish bilateral symmetry.



The cleavage is unequal holoblastic ((first and second cleavages are, however, equal holoblastic).

Polar bodies Animal hemisphere

Gray crescent Vegetal hemisphere Jelly coats (3) Vitelline membrane Fig. 7.44 : Fertilized egg of Frog



The development is indirect. The larva is tadpole.



The important stages of development are – Zygote → Morula → Blastula → Gastrula → Neurula → Tail-bud stage → Gill bud-stage → External gill stage → Internal gill stage ( mature tadpole). Animal hemisphere

Animal hemisphere

Cortical layer

Region of sperm entrance

Notochord Ectoderm

Endoderm Region of gray crescent, future dorsal lip and anus

Vegetal hemisphere

Vegetal hemisphere

(a) Entire

(b) Sagittal Section

Archenteron

Gastral mesoderm

(A)

Yolk plug

Lateral blastopore lip

(B)

Fig. 7.45 : (A) Blastula, (B) Gastrula Neurocoel

Hindgut

Midgut

Notochord Foregut rudiment of eye

Neurenteric canal Rectum Proctodeum

Yolk

Optic vesicle Head mesenchyme Oral evogination Heart mesenchyme Liver diverticulum

external gills

myotomes

olfactory pit mandibular arch stomodaeum

Fig. 7.46 : Neurula

oral sucker or cement gland

gill clefts

cloacal aperture

tail fin

ANIMAL TISSUES (HISTOLOGY) & COCKROACH, EARTHWORM AND FROG eye

3 external gills

myotomes

olfactory pit olfactory pit mouth with horny jaws oral opercular fold sucker

cloacal aperture

tail fin

mouth with horny jaws

(A)

eye

myotomes

tail fin

hindlimb operculum spiracle (B)

cloacal aperture

Fig. 7.47 : (A) Ext. gill stage (B) Tadpole



Mature tadpole has pronephros kidney, cartilaginous skeleton and respires through skin and internal gills (4-pairs). The blood vascular system is fish like. The heart is 2-chambered. The alimentary canal is coiled like a spring. It is herbivore. The fore limbs and hind limbs are developed, but the fore limbs are not visible due to the presence of operculum over gills. The excretory product is ammonia.

Metamorphosis 

It occurs in the presence of thyroxine hormone. In deficiency of thyroxine or iodine the tadpole increases in size and does not undergo metamorphosis.



The emergence of fore limbs out of operculum is the first sign of metamorphosis.



The nervous system is least affected and blood vascular system is most affected during metamorphosis.



The important destructive/regressive changes in metamorphosis are – (i) Shedding of horny jaws and teeth, (ii) Resorption of tail by autolysis, (iii) Disappearance of cloacal tube, lateral line organ, operculum, spiracle and internal gills.

Biological importance of frog 

It is used in laboratory for teaching and research.



Being insectivorous it protects the crops from insect-pests and saves the expenditure on insecticides.



Its muscular legs are used as food / pickle.



Froglets or tadpoles can be used as fish baits.



Frog also forms an important link in ecosystem and maintains ecological balance.

309

310

BIOLOGY

EXERCISE - 1 | NCERT BASED QUESTIONS 1.

2.

3.

4.

5.

6.

7.

8.

9. 10.

Out of the four basic types of tissues, which is not the one ? (1) Muscular tissue (2) Skeletal tissue (3) Neural tissue (4) Epithelial tissue The outside or inside lining of a body organ is formed by (1) Epithelial tissue (2) Neural tissue (3) Muscular tissue (4) Variable and differs from organ to organ The epithelium of air sacs of lungs and the walls of blood vessels is (1) Simple cuboidal epithelium (2) Simple squamous epithelium (3) Stratified squamous epithelium (4) Simple columnar epithelium The function of following epithelium is not secretion and absorption (1) Simple cuboidal epithelium (2) Simple columnar epithelium (3) Simple squamous epithelium (4) Brush bordered epithelium The inner surface of hollow tubes, like bronchioles and fallopian tubes, have (1) Brush bordered epithelium (2) Stratified squamous epithelium (3) Ciliated epithelium (4) Simple cuboidal epithelium Goblet glands are (1) Unicellular exocrine glands of intestine (2) Unicellular endocrine glands of intestine (3) Multicellular exocrine glands of gut (4) Multicellular endocrine glands of gut The epithelium of following structure provides protection against chemical and mechanical stresses (1) Skin (2) Pharynx (3) Buccal cavity (4) All of these Which of the following type of cell junction is not found in animal tissues (1) Desmosome (2) Tight junction (3) Gap junction (4) Plasmodesmata Following is the most abundant tissue in animals (1) Epithelial tissue (2) Neural tissue (3) Muscular tissue (4) Connective tissue Dermis of skin has (1) Loose connective tissue (2) Dense regular c.t. (3) Dense Irregular c.t. (4) Epithelial tissue

11.

12.

13.

14.

15.

16.

17.

18.

19.

20.

Mast cells are associated with (1) Exocrine glands (2) Endocrine glands (3) Areolar connective tissue (4) Neural tissue Tendons and ligaments are the example of (1) Areolar connective tissue (2) Adipose tissue (3) Dense regular con.tissue (4) Loose conn. tissue In all connective tissues except the following, the cells secretes the fibres of collagen or elastin protein (1) Bone (2) Cartilage (3) Areolar connective tissue (4) Fluid connective tissue The fibres of the following muscles are fusiform and do not show striations (1) Skeletal muscles (2) Cardiac muscles (3) Both of these (4) Smooth muscles The chondrocytes of connective tissue are (1) Fibre secreting cells (2) Bone forming cells (3) Cartilage cells (4) Bone eating cells Muscles of intestine and blood vessels are (1) Involuntary and smooth (2) Voluntary and smooth (3) Involuntary and striated (4) Voluntary and striated Intercalated discs are the communication junctions between the cells of (1) Cardiac muscles (2) Striped muscles (3) Adipose tissue (4) Nerve and Striated muscles Neuroglia are (1) Excitable cells of neural tissue (2) Supporting and non-excitable cells of neural tissue (3) Two to three times in volume of neural tissue (4) Protective and excitable cells of neural tissue The following are the major proteins of plasma (1) Globulin, Bilirubin and fibrinogen (2) Haemoglobin, fibrinogen and albumin (3) Globulin, albumin and Haemoglobin (4) Albumin, globulin and fibrinogen Consider the following three statements and mark the right options A. The plasma without clotting factors is called semen B. Thymus is called the graveyard of RBCs C. Thrombocytes are the cell fragments produced from

ANIMAL TISSUES (HISTOLOGY) & COCKROACH, EARTHWORM AND FROG megakaryocytes (1) Only A is correct (2) Both A and C are correct (3) Both B and C are correct (4) Only C is correct 21. Albumin in plasma helps in (1) Osmotic balance (2) Defense mechanism (3) Blood clotting (4) Nourishing the blood elements 22. RBCs in human are (1) Biconcave and nucleated (2) Biconvex and nucleated (3) Bivoncave and enucleated (4) Biconvex and enucleated 23. The most and the least abundant leucocytes are respectively (1) Neutrophils and basophils (2) Lymphocytes and monocytes (3) Lymphocytes and basophils (4) Neutrophils and monocytes 24. Histamine, serotonin and heparin are secreted by (1) Thrombocytes (2) Lymphocytes (3) Monocytes (4) Basophils 25. B and T forms, responsible for the immune response are the type of (1) Thrombocytes (2) Lymphocytes (3) Eosinophils (4) Granulocytes 26. Read the following statements and mark the right option A. A healthy person has 12 to 16 g. of haemoglobin per 100 ml of blood B. The number of platelets in a normal individual is 1.5 lac to 3.5 lac per mm3 of blood C. Eosinophils are involved in allergic reactions (1) Only B is correct (2) Only B and C are correct (3) Only A and C are correct (4) All A, B and C are correct 27. The haemoglobin content per 100 ml of blood of a normal healthy human adult is (1) 5 - 11 g (2) 25 - 30 g (3) 17 - 20 g (4) 12 - 16 g *28. Following pores are present in segments number 5th to 9th only (1) Female genital pores (2) Spermathecal pores (3) Male genital pores (4) Nephridiopores *29. Read the following statements and mark the right option A. The numebr of segments inthe body of earthworm is 100-120 B. Prostomium is the first segment and contains mouth C. Clitellum is present in segments numbered 14 to 16. (1) A and B are correct (2) B and C are correct (3) A and C are correct (4) All, A, B and C are correct

* Asteric Qs. not included in NEET Syllabus.

311

*30. Intestinal setae in earthworm – intestine project from (1) 15th segment (2) 18th segment (3) 21st segment (4) 26th segment *31. Setae in earthworm are present in (1) All the segments of body (2) All segments except 1st and last (3) In cliteller sements only (4) All segments except 1st, last and clitellum *32. The blood glands that produce haemoglobin and blood cells, in earthworm, are located in (1) 14th to 16th segments (2) Typhlosolar region (3) 6th to 9th segments (4) 4th to 6th segments *33. Pharyngeal nephridia in earthworm occur in segments number (1) 3rd to last (2) 15th to last th th (3) 4 to 6 only (4) 1st to 13th only *34. Given below are four statements (A to D) regarding reproductive system of earthworm A. Testes are two pairs and are present in segments number 10th and 11th B. Male genital aperture is anterior to female genital aperture C. Accessory glands secrete cocoon D. Ovaries are attached to 12/13th septa which two of the above statements are correct? (1) A & B (2) B & C (3) A & D (4) C & D 35. Fore wings in cockroach arise from (1) Mesothorax and are dark and leathery (2) Prothorax and are called tegmina (3) Mesothorax and are transparent and membranous (4) Prothorax and are transparent and membranous 36. Genital or brood pouch in female cockroach is formed by (1) 7th, 8th and 9th sterna (2) 9th and 10th terga, 9th sterna (3) 9th and 10 terga only (4) 9th and 10th sterna only 37. Which statement regarding anal cerci and anal style in cockroach is correct? (1) Anal cerci are absent but anal styles are present in male (2) Anal cerci are absent and anal styles are present in female (3) Anal styles are absent and anal cerci are present in male (4) Anal styles are absent and anal cerci are present in female 38. At the junction of mid gut and hind gut in cockraoch is / are present (1) Gizzard (2) 6 to 8 blind caecae (3) 100 to 150 filamentous Malpighian tubules (4) Crop

312 39.

40.

41.

42.

BIOLOGY Consider the following 3-statements regarding cockraoch and mark the correct option A. Head is formed by the fusion of 6-segments B. Mouth parts are biting and chewing type C. Crop is the part of mid gut (1) Only B is correct (2) Only B and C are correct (3) Only A and B are correct (4) Only C is correct Mark the incorrect statement regarding the anatomy of cockroach (1) BVS is open type with colourless haemolymph (2) Spiracles are ten pairs (3) Fat body, Nephrocytes and uricose glands are accessory excretory structures (4) There are 9-ganglia on ventral nerve cord of abdomen Read the following statements (A–D) and mark the option that has both the correct statements A. Each eye consists of about 2000 ommatidia B. Each testis lies in 4th to 6th abdominal segments C. Each ovary has 16 ovarioles D. Spermathecae are two and are present in 6th abdominal segment (1) A & B (2) B & C (3) C & D (4) A & C Mark the incorrect statement for cockroach (1) Nymph undergoes 3-4 moults to reach adult form (2) Spermatophore is the bundle of sperms discharged during copulation

* Asteric Qs. not included in NEET Syllabus.

*43.

*44.

*45.

*46.

(3) Each ootheca has 14 to 16 eggs (4) Its development is paurometabolous A female frog has (1) Copulatory pad (2) Neck (3) Vocal sac (4) Cloaca In frog the gaseous exchange during hibernation takes place through (1) Skin (2) Buccal cavity (3) Lungs (4) Buccal cavity and longs both The right atrium in frog receives the blood directly from (1) Conus arteriosus (2) Pulmonary veins (3) Vena cava (4) Sinus venosus Which statements regarding frog is incorrect (1) Ureter in males acts as a Urinogenital duct (2) It is ureotelic (3) It has both renal and hepatic portal system (4) Vas efferentia from testes open into epididymis/ vas deferens

ANIMAL TISSUES (HISTOLOGY) & COCKROACH, EARTHWORM AND FROG

313

EXERCISE - 2 | Window to Competitive Exams 1. 2.

3.

4.

5.

6.

7.

8. 9.

10.

11.

Compound squamous epithelium is found in (1) Stomach (2) Intestine [BHU ‘95] (3) Trachea (4) Pharynx In mammals the Glisson’s capsules are found in [Haryana ‘95] (1) Liver (2) Pancreas (3) Spleen (4) Lungs Keratinized stratified squamous epithelium is found in [AMU ‘95] (1) Trachea (2) Epidermis (3) Mouth cavity (4) Lining of blood vessels Cingulum of earthworm is concerned with [CPMT ‘88, ‘89, ‘92, ‘95] (1) Copulation (2) Cocoon formation (3) Burrowing (4) Spermatogenesis In earthworm, setae are totally absent (1) In clitellum [RPMT ‘95] (2) In the first segment (3) In Clitellum and the last segment (4) In Clitellum, first and last segments One of the following is common in earthworm and cockroach [CPMT ‘94; AFMC ‘95] (1) Double solid and ventral nerve cord (2) Presence of Nephridia (3) Equal body segments (4) None of the above The part of cockroach having both exoskeleton and endoskeleton (tentorium and apodemes) is [RPMT ‘95] (1) Head (2) Thorax (3) Abdomen (4) Both (1) and (2) Young one of the cockroach is called (1) Naid (2) Grub [RPMT ‘95] (3) Nymph (4) Maggot The functional units of compound eye of an insect are called [MAHE ‘95] (1) Fenestrae (2) Ocelli (3) Radula (4) Ommatidia RBCs count is carried out by [Orissa ‘95] (1) Sphygmomanometer (2) Haemoglobinometer (3) Haemocytometer (4) Electrocardiograph Which one of the following cellular components of the blood is responsible for the production of antibodies? [CBSE ‘96] (1) Thrombocyte (2) Lymphocyte (3) Monocyte (4) Erythrocyte

12.

13.

14.

15.

16.

17.

18.

19.

20.

21.

22.

Brunner’s glands are found in [CPMT ‘96] (1) Liver (2) Mucosa of intestine (3) Submucosa of first part of small intestine (4) Mucosa of duodenum What is the percentage of haemoglobin in wet RBC? [CPMT ‘96] (1) 3% (2) 33% (3) 10% (4) 60% Peyer’s patches contain [MP ‘96] (1) Mucus (2) Sebum (3) RBCs (4) Lymphocytes The blood cell which shows phagocytosis is (1) Monocyte (2) Basophil [PCS ‘96] (3) Eosinophil (4) Platelet Vitamin K is required for: [EAMCET ‘96] (1) Formation of thromboplastin (2) Synthesis of prothrombin (3) Conversion of fibrinogen to fibrin (4) Conversion of prothrombin to thrombin In the blood generally [EAMCET ‘96] (1) WBCs are more in number than RBCs (2) Red blood corpuscles are more in number than white blood corpuscles (3) Platelets are less in number than WBCs (4) Red blood corpuscles are less in number than platelets The largest lymphatic organ in vertebrates is [Orissa ‘96] (1) spleen (2) pancreas (3) liver (4) none Nephridia of earthworm are analogous to [CBSE ‘96] (1) Trichocyst of Paramecium (2) Tracheae of insects (3) Flame cells of Taenia (4) Gills of fish Typhlosole of Pheretima can be found in [CPMT ‘96] (1) Oral cavity (2) Gizzard (3) Stomach (4) Intestine In which segments the clitellum is present in earthworm ? [BHU ‘96] (1) 16 segments (2) 17-19 segments (3) 14-16 segments (4) 5-6 segments Pharyngeal glands are rich in chromaphil cells in earthworm which secrete [RPMT ‘96] (1) Alkaline salts to reduce the acidity of humus food (2) Mucus (3) Protease enzyme (4) Both (2) and (3)

314 23.

24.

25. 26.

27. 28. 29.

30.

31. 32.

33. 34.

35.

36.

BIOLOGY Spermathecal pores of Pheretima can be traced in segments [CPMT ‘96] (1) 5/6, 6/7, 7/8 and 8/9 (2) 6/7, 7/8, 8/9 and 9/10 (3) 1/2, 2/3, 3/4 and 4/5 (4) 14/15, 15/16 16/17 and 17/18 Ten pairs of spiracles with trachea for respiration are present in [BHU ‘96] (1) Ticks and mites (2) All arthropods (3) Housefly (4) Cockroach Longest podomere of cockroach’s leg is [Bihar ‘96] (1) Coxa (2) Trochanter or femur (3) Tibia (4) Tarsus Metamorphosis takes about ————— in cockroach [RPMT ‘96] (1) 10 – 12 months (2) One month (3) 5 – 13 Weeks (4) Two years Transitional epithelium is found in [AMU ‘97] (1) Lungs (2) Liver (3) Urinary bladder (4) Stomach The lining of bone marrow cavity is called [AIIMS ‘97] (1) Endosteum (2) Endomyosium (3) Periosteum (4) Endothelium Stratum germinativum is an example of which kind of epithelium? [CBSE ‘97] (1) Cuboidal (2) Ciliated (3) Columnar (4) Both (I) and (3) Basement membrane is made up of [CBSE ‘97] (1) Epidermal cell only (2) Endodermal cell (3) Cell product of epithelial cell (4) Both (1) and (2) Heparin is secreted by [BHU ‘97] (1) Liver cell (2) Mast cell (3) Both (1) and (2) (4) Kidney The epithelium which lines the inner surface of the stomach of rabbit is made up of [CPMT ‘89; AFMC 97] (1) Squamous epithelium (2) Stratified epithelium (3) Pseudostratified epithelium (4) Columnar epithelium Which of the following is not a granulocyte? [CBSE ‘97] (1) Lymphocyte (2) Neutrophil (3) Basophil (4) Eosinophil Epiphyseal plates help in the [BHU ‘97] (1) Formation of the bone (2) Thickening of the bone (3) Elongation of the bone (4) None of these Which of the following is helpful for erythropoiesis? [BHU ‘97] (1) Fe2+ (2) Mg2+ (3) Cu2+ (4) Ca2+ Red bone marrow occurs in membraneous bones such as [CPMT ‘97] (1) All flat bones of skull, vertebrae, sternum and ribs (2) only in centrum of vertebrae (3) only in centrum of vertebrae and skull (4) none of these

37. 38.

39.

40.

41. 42.

43.

44.

45. 46.

47.

48.

49.

50.

The typhosole of earthworm is related with [BHU ‘97] (1) Excretion (2) Respiration (3) Reproduction (4) Absorption Earthworm has [CET Chd. ‘97] (1) Open circulatory system (2) Closed circulatory system (3) Unique circulatory system (4) No circulatory system Who wrote a memoir on the earthworm to describe its all structure and function ? [CPMT ‘91; BHU ‘97] (1) Darwin (2) Beni Prasad (3) K.N. Behl (4) Lamarck Saliva of cockroach is rich in the following enzymes [RPMT ‘97] (1) Amylase (2) Pytalin (3) Zymase (4) All above The heart of cockroach is [RPMT ‘97] (1) Myogenic (2) Neurogenic (3) Neuro-myogenic (4) None of the above They perform excretion in cockroach [RPMT ‘97] (1) Malpighian tubules, urate cells and uricose glands (2) Cells of mesenteron (3) Cells of gizzard (4) All above The wings are either rudimentary or vestigial in [CPMT ‘97] (1) Female cockroach of Blatta orientalis (2) Male cockroach of Blatta orientalis (3) Female cockroach of Periplaneta americana (4) Male cockroach of Periplaneta americana Secretions of corpora allata in insects help in [RPMT ‘97] (1) Growth (2) Metamorphosis (3) Peristalisis (4) Both (1) and (2) Collagen fibres of connective tissue are (1) Yellow (2) White [RPMT ‘98] (3) Red (4) Transparent The non-excitable, variously shaped and found between neurons are [KCET ‘98] (1) Dendrites (2) Nissl bodies (3) Glial cells (4) Schwann cell The longest cells in human body are [BHU ‘98] (1) Nerve cells (2) Bone cells (3) Leg muscle cells (4) Heart-muscle cells Non-elastic but flexible tissue which serves to attach the muscles to the bone is [KCET ‘98] (1) Lymph. (2) Ligament (3) Tendon (4) Adipose Ciliated epithelium lines the [RPMT ‘98] (1) Tracheal and fallopian tube (2) Bile duct and ureter epithelium (3) Trachea and oesophagus (4) Pharyngeal and stomach mucosae During blood clotting, platelets release [EAMCET ‘98] (1) Thrombokinase (2) thrombin (3) fibrinogen (4) prothrombin

ANIMAL TISSUES (HISTOLOGY) & COCKROACH, EARTHWORM AND FROG 51.

52.

53.

54.

55.

56.

57.

58.

59.

60.

61.

62.

63.

64.

65.

Fluid part of blood after removal of corpuscles is [BCECE ‘97; MP 98] (1) Plasma (2) Lymph (3) serum (4) Vaccine Humoral antibodies are produced by [BHU ‘98] (1) B-cells (2) T-cells (3) globins (4) Plasma cells Which are not true cells in the blood? [EAMCET ‘98] (1) platelets (2) monocytes (3) basophils (3) neutrophils Ligaments and tendons are formed of (1) Epithelial tissue [MP MP ‘96; AFMC ‘99] (2) Muscular tissue (3) Cartilage (4) Connective tissue Example of loose connective tissue is [CPMT ‘99] (1) Areolar tissue (2) Adipose tissue (3) Both (1) and (2) (4) None The component of blood which prevents its coagualtion in the blood vessels is [AIIMS ‘99] (1) plasma (2) heparin (3) thrombin (4) haemoglobin Tendon is made up of [CBSE ‘99] (1) inelastic connective tissue fibres (2) elastic connective tissue fibres (3) inelastic and elastic connective tissue fibres (4) only collagen fibres pH of human blood is [MP ‘99] (1) 7.4 (2) 6.2 (3) 9.0 (4) 7.5 - 8.0 Tendons are made up of following proteins [CBSE ‘99] (1) Collagen (2) Elastin (3) Keratin (4) All above Ligament is made up of mainly [CBSE ‘99] (1) Collagen protein (2) Elastin protein (3) Keratin protein (4) All above Lymph is colourless because [MP ‘99] (1) WBCs are absent (2) WBCs are present (3) Haemoglobin is absent (4) RBCs are absent Brush bordered epithelium is found in [CPMT ‘99] (1) stomach (2) small intestine (3) fallopian tube (4) trachea Lymph glands (nodes) form [MP ‘99] (1) antibodies (2) antigens (3) lymph (4) hormones Megakaryocytes [MP 2000] (1) produce leucocytes (2) are called bone cells (3) are carriers of oxygen (4) produce blood platelets Process from osteoblasts are called [MP 2000] (1) Lamellae (2) Canaliculi (3) Dendrites (4) Haversian canals

66.

67.

68.

69.

70.

71.

72.

73.

74.

75.

76.

77.

315

The lining of marrow cavity is called [AIIMS ‘97; Haryana 2000] (1) Epiosteum (2) Periosteum (3) Endosteum (4) Sarcolemma Which of the following vertebrate tissues would be an excellent source of collagen? [PCS 2000] (1) Liver (2) Nerve (3) Muscle (4) Tendon If frog’s long bone (femur) is treated with dilute HCI [CBSE 2000] (1) It becomes hard and brittle (2) It becomes soft and flexible (3) It will break into pieces (4) It becomes calcified What type of cartilage forms the whole of the adult skeleton of cartilaginous fishes? [Kerala 2000] (1) Elastic (2) Hyaline (3) Typical (4) Fibrous Adam’s apple represents [Punjab 2000] (1) Cartilage of larynx (2) thyroid cartilage of trachea (3) Both above (4) None above In polycythemia the number of red cells increases greatly. This causes adverse effects due to (1) decreased blood volume [PCS 2000] (2) increased circulation time (3) increased viscosity of blood (4) increased availability of oxygen The polysaccharide portion of a proteoglycan present in the matrix of cartilage is known as [CBSE 2000] (1) ossein (2) cartilin (3) casein (4) chondroitin What are the functions of goblet cells? (1) Production of HCl [MP 2000] (2) Production of mucus (3) production of enzymes (4) Production of hormone Which cartilage is present in trachea, larynx and bronchi? [AFMC 2000] (1) hyaline (2) elastic (3) fibrous (4) calcified In Pheretima, the Septa are absent between (1) 5/6 and 7/8 segments [CPMT 2000] (2) First four segments (3) 5/6 and 10 and 11 segments (4) 7/8 and 8/9 segments In earthworm arrangement of blood vessels is [BHU ‘94, 2000] (1) Same throughout the body (2) Different in first 13 segments (3) Different in last 13 segments (4) Different in middle 13 segments Blood vessel in earthworm which has valves is [AIIMS 2000] (1) Dorsal (2) Ventral (3) Lateral (4) Integumentary

316 78.

79.

80.

81.

82. 83. 84.

85.

86.

87. 88.

89.

90.

BIOLOGY Entero-nephridia of earthworm helps in [CBSE 2000] (1) Nutrition (2) Respiration (3) Excretion (4) Osmoregulation Cockroach and Ascaris are similar in one of the following cases [CBSE 2000] (1) Dorsal tubular nerve cord (2) Nephridia (3) Sexual dimorphism (4) Pseuocoel The abdomen of cockroach is composed of segments [Haryana 2000] (1) 6 (2) 12 (3) 10 (4) 11 Following is not the cell of areolar tissue [Karnataka ‘01] (1) Plasma cell (2) Adipose cell (3) Macrophage (4) Schwann cell Formation of blood is termed [AFMC ‘01] (1) anaemia (2) haemolysis (3) plasmolysis (4) haemopoiesis An example of merocrine gland is [MP ‘01] (1) pineal gland (2) salivary gland (3) mammary gland (4) sebaceous gland This one is the characteristic of epithelial tissue [Karnataka ‘01] (1) Tissues are highly vascularized (2) These cells never produce glands (3) The cells will have a rapid rate of cell division (4) Large intercellular spaces are seen between cells Increase in capillary permeability is induced by [EAMCET ‘01] (1) Heparin (2) Histamine (3) Gastrin (4) Fibrin The following are required for blood clotting in mammals [MP MP ‘01] (1) K+ and vitamin K (2) Ca2+ and vitamin A (3) Ca2+ and vitamin K (4) K+ and vitamin E This is not the cell of areolar tissue [KCET ‘01] (1) Macrophages (2) Schwann cell (3) Plasma cell (4) Adipose cell The function of blood glands in Pheretima is [EAMCET ‘01] (1) Maintenance of blood volume (2) Maintenance of blood circulation (3) Production of RBC (4) Production of phagocytes Coelom in cockroach is [EAMCET ‘01] (1) Enterocoel (2) Schizocoel (3) Pseudocoel (4) None In medullated nerve fibres nodes of Ranvier are (1) area of swelling on axons [Orissa ‘02] (2) areas found in stomach wall (3) area where myelin sheath is absent on neuron (4) nodes formed in striated muscles

91. 92. 93.

94.

95.

96.

97.

98.

99.

100.

101.

102. 103. 104.

Spleen [Orissa ‘02] (1) Forms blood (2) forms hormones (3) helps in digestion (4) all Mammary gland is a modified [MP ‘02] (1) Endocrine gland (2) Eccrine gland (3) Merocrine gland (4) Apocrine gland Least capacity of regeneration in mammals is found in [CPMT ‘90, 02] (1) Nervous tissue or brain (2) Endothelium of blood vessels (3) Skeletal tissue of bones (4) Epithelial tissue of skin The difference between blood and lymph is [Orissa ‘02] (1) blood has WBC while lymph has RBC (2) blood has dissolved salt while lymph has no cells (3) blood has RBC and WBC while lymph has no cell (4) blood has RBC and WBC while lymph has only WBC Sebaceous glands in the skin of mammals are (1) Simple coiled tubular gland [Kerala ‘02] (2) Simple tubular gland (3) Compound tubular gland (4) Simple branched alveolar gland Lining of trachea is made up of [Kerala ‘02] (1) Simple squamous epithelium (2) Stratified epithelium (3) Pseudostratified epithelium (4) Stratified cuboidal epithelium Lymph contains [CBSE ‘02] (1) Everything like blood except RBC and few blood proteins (2) Serum and WBC (3) WBC and RBC (4) Blood Plasma The outer covering of non-myelinated neurons in brain is [MAHE ‘02] (1) neurilemma (2) Axolemma (3) Sarcolemma (4) Oolemma The end of long bones are covered with [Bihar ‘01; CBSE ‘02] (1) Muscles (2) Cartilage (3) Ligaments (4) Epithelium The protein present in the matrix of cartilage is [CBSE 2000; AFMC ‘02] (1) Chitin (2) Chondrin (3) Ossein (4) Chondriotin The lining of salivary and pancreatic duct is made up of [Punjab ‘02] (1) Squamous epithelium (2) Cuboidal epithelium (3) Ciliated epithelium (4) Pseudostratified epithelium Histamine is secreted by [Kerala ‘02; AFMC ‘02] (1) Mast cells (2) Fibroblast (3) Histiocytes (4) Melanocytes Stratum corneum is absent in [BHU ‘02] (1) Fish (2) Frog (3) Reptiles (4) Birds Kupffer cells are [BHU ‘02] (1) Phagocytic (2) Nutritive (3) Secretive (4) Excretory

ANIMAL TISSUES (HISTOLOGY) & COCKROACH, EARTHWORM AND FROG 105. Epithelial tissues arise from [MP ‘02] (1) Ectoderm (2) Endoderm (3) Mesoderm (4) All the above 106. Fallopian tube is lined by following epithelium [IPU ‘02] (1) Ciliated (2) Pseudostratified (3) Cuboidal (4) Columnar 107. The cell used for the filtration for urine formation are [BVP ‘02] (1) Squamous epithelium (2) Columnar epithelium (3) Cuboidal epithelium (4) Ciliated epithelium 108. Connective tissue is [Orissa ‘02] (1) ectodermal in origin without intercellular spaces (2) Mesodermal in origin without interecellular spaces (3) ectodermal in origin without intercellular spaces (4) mesodermal in origin with intercellular spaces 109. Which of the following statements is correct for node of Ranvier of nerve? [CBSE ‘02] (1) Covered by myelin sheath (2) Neurilemma is discontinuous (3) Myelin sheath is discontinuous (4) Both neurilemma and myelin sheath are discontinuous 110. What will happen if ligaments are cut or broken? (1) No movements at joints [CBSE ‘02] (2) Bones will become fixed (3) Bones will become unfixed (4) Bone will move freely at joints 111. A bipolar neuron has [Karnataka ‘02] (1) 1 dendrite and 1 axon (2) 2 axons and 2 dendrite (3) 2 dendrites and 1 axon (4) 2axons and 1 dendrite 112. In female Pheretima posthuma pharyngeal nephridia are present in [Vellore ‘02] (1) 3, 4, 5 (2) 7, 8, 9 (3) 4, 5, 6 (4) 5, 6, 7 113. Salivary duct of cockroach opens at [Vellore ‘02] (1) Hypopharynx (2) Mandibular region (3) Labium (4) Ist maxilla 114. Haemoglobin A consists of [Jharkhand ‘03] (1) 1α chain and 1β chain (2) 2α chains and 1β chain (3) 2α chains and 2β chains (4) 1α chain and 2β chains 115. Life span of human RBCs is [MP ‘01; CPMT ‘03] (1) 120 days (2) 20 days (3) 9 days (4) 90 days 116. Which is the principal cation in the plasma of the blood? [CBSE ‘99; Punjab ‘03; Jharkhand ‘03] (1) Sodium (2) Potassium (3) Magnesium (4) Calcium 117. The covering layer of a bone is called as [Vellore ‘03] (1) epimysium (2) ependyma (3) periosteum (4) endosteum

317

118. Which one of the following contains the largest quantity of extracellular material? [CBSE ‘03] (1) Areolar tissue (2) Striated muscle (3) Stratified epithelium (4) Myelinated nerve fibres 119. Nasal epithelium is made up of [Vellore ‘03] (1) columnar epithelium (2) glandular epithelium (3) keratinized epithelium (4) transitional epithelium 120. In which of the following tissue is the matrix not a product of synthesis of its cells? (1) Vascular tissue [Karnataka ‘03] (2) Osseous tissue (3) Loose connective tissue (4) Adipose tissue 121. The most appropriate definition for neuroglial cells is that they are [Kerala ‘03] (1) sensory cells (2) secretory cells (3) nonsensory supporting cells (4) sensory and supporting cells 122. Body cavity of cockroach is [MAHE ‘03] (1) Haemocoel (2) Pseudocoel (3) Coelenteron (4) Coelom 123. How the male cockroach can be distinguished from the female cockroach ? [MAHE ‘03] (1) Presence of anal cirri in female cockroach (2) Presence of anal styles in male cockroach (3) Absence of anal style in male cockroach (4) Absence of anal cirri in male cockroach 124. You are required to draw blood from a patient and to keep it in a test tube for analysis of blood corpuscles and plasma. You are also provided with the following four types of test tubes. Which of them will you not use for the purpose? (1) Chillled test tube [CBSE ‘04] (2) Test tube containing heparin (3) Test tube containing sodium oxalate (4) Test tube containing calcium bicarbonate 125. Compound saccular gland is (1) sweat gland [CPMT ‘01; AMU ‘05] (2) sebaceous gland (3) mammary gland (4) crypt of Lieberkuhn 126. Mammary gland of eutherians is modified [CPMT ‘92; MAHE ‘05; Orissa ‘05] (1) Sweat gland (2) mucous gland (3) Sebaceous gland (4) None above 127. Intervertebral disc is made up of (1) Elastic cartilage [AIIMS ‘95; Kerala ‘05] (2) Fibrous cartilage (3) Calcified cartilage (4) Hyaline cartilage

318 128. The RBCs of camel are [Orissa ‘95; MAHE ‘05] (1) Oval and non-nucleated (2) Oval and nucleated (3) Circular, biconcave and non-cucleated (4) Circular, biconvex and nucleated 129. Sprain is caused due to the excessive pulling of [Kerala 2000; AIIMS 2000; Orissa ‘05] (1) Muscles (2) Tendons (3) Ligaments (4) All above 130. Four healthy people in their twenties got involved in injuries resulting in damage and death of a few cells of the following. Which of the cells are least likely to be replaced by new cells? [CBSE’05] (1) Liver cells (2) Neurons (3) Malpighian layer of the skin (4) Osteocytes 131. Pseudostratified epithelium is found in [AMU ‘05] (1) Oesophagus (2) Respiratory tract (3) Urinary tract (4) Kidney 132. Pacinian corpuscles are abundantly found in [MAHE ‘05] (1) skin (2) blood (3) tissue (4) kidney 133. Nerve cells do not possess [MAHE ‘05] (1) neurilemma (2) sarcolemma (3) dendrite (4) axon 134. Which of the following statements are wrong? [Kerala ‘05] (i) Leucocytes disintegrate in the spleen and liver. (ii) RBC, WBC and blood platelets are produced by bone marrow. (iii) Neutrophils bring about destruction and detoxification of toxins of protein origin. (iv) The important function of lymphocytes is to produce antibodies. (1) (i) and (ii) only (2) (i) and (iv) only (3) (i) and (iii) only (4) (ii) and (iii) only 135. The progenitors that are formed in bone marrow and differentiate elsewhere are : [EAMCET ‘05] (1) Pre-NK cell (2) Pre-Erythroblast (3) Pre-T Cell (4) Myeloblast 136. The hump of camel is made up of which of the following tissues? [AMU ‘05] (1) areolar tissue (2) adipose tissue (3) epithelial tissue (4) muscular tissue 137. Match the items in colum A with column B and choose the correct answers given below [Kerala ‘05] Column A Column B 1. neuron A. ossein 2. bone matrix B. nissl bodies 3. RBC of man C. antibodies 4. lymphocytes D. non-nucleated. (1) 1 - D, 2 - B, 3 - C, 4 - A (2) 1 - D, 2 - A, 3 - C, 4 - B (3) 1 - D, 2 - B, 3 - A, 4 - C (4) 1 - B, 2 - A, 3 - D, 4 - C

BIOLOGY 138. Heparin is synthesised in [BHU ‘05] (1) liver (2) kidney (3) saliva (4) pancreas. 139. Thousand of year old mummies are still in their condition as they were before due to the non destruction of (1) yellow elastin fibres [BHU ‘05] (2) white elastin fibres (3) collagen fibres (4) veins 140. Erythrocyte maturing factor is [AMU ‘05] (1) folic acid (2) cyanocobalmine (3) vitamin B2 (4) vitamin C 141. Nerve cells do not divide because they do not have [BHU ‘05] (1) nucleus (2) centrosome (3) golgi body (4) mitochondria. 142. Which of the following is phagocytic ? (1) monocyte (2) R.B.C [BHU ‘05] (3) eosinophil (4) basophil 143. Abnormal fall in the total count of WBCs in the human blood is called [Manipur ‘05] (1) anaemia (2) polycythemia (3) leucopenia (4) leukaemia 144. Choose the odd pair out in the following [KCET ‘05] (1) areolar connective tissue - collagen (2) epithelium -keratin (3) neuron - melanin (4) muscle fibre -actin. 145. Which of the following tissue originates exclusively from the ectoderm of the embryo ? [KCET ‘05] (1) muscular tissue (2) epithelial tissue (3) nervous tissue (4) connective tissue 146. Which of the following structures are derivatives of the endoderm? [KCET ‘05] (1) alimentary canal and respiratory structures (2) muscles and blood (3) excretory and reproductive structures (4) skin and nerve cord. 147. Fat is present in which part of a neuron [AMU ‘05] (1) cyton (2) node of Ranvier (3) dendron (4) axon 148. During cold the hairs are raised and brought up in a more or less vertical position by [JK ‘05] (1) sebaceous glands (2) hair follicles (3) capillary plexus (4) arrector pilli 149. Leucopenia is the condition where [Orissa ‘05] (1) leucocytes decrease below 5000 per cubic mm of blood (2) bone marrow is destroyed (3) total number of lymphocyte decreases from 2% to 0.5% (4) leucocytes increase to about 6000

ANIMAL TISSUES (HISTOLOGY) & COCKROACH, EARTHWORM AND FROG 150. Clitellum of Pheretima is primarily concerned with [CPMT ‘85, ‘88, ‘89; BCECE ‘05] (1) Copulation (2) Excretion (3) Sexual dimorphism (4) Production of cocoons 151. Which one of the following groups of structures/ organs have similar function? [AIIMS ‘05] (1) Typhlosole in earthworm, intestinal villi in rat and contractile vacuole in Amoeba. (2) Nephridia in earthworm, Malpighian tubules in cockroach and urinary tubules in rat. (3) Antennae of cockroach, tympanum of frog and clitellum of earthworm (4) Incisors of rat, gizzard (proventriculus) of cockroach and tube feet of starfish. 152. The labrofrontal nerves in Cockroach originate from : [EAMCET ‘05] (1) Sub oesophageal ganglia (2) Supra oesophageal ganglia (3) Antennary nerves (4) Frontal ganglia 153. The mouth parts of cockroach are of (1) piercing and sucking type [Manipur ‘05] (2) chewing and lapping type (3) biting and chewing type (4) siphoning type 154. Which structure of man is similar to spiracle of cockroach? [Orissa ‘05] (1) nostril (2) bronchiole (3) lungs (4) alveoli 155. Blood of which of the following is colourless? [Haryana ‘05] (1) earthworm (2) leech (3) cockroach (4) frog 156. Earthworms have how many segments? [Haryana ‘05] (1) 85 – 400 (2) 100 -200 (3) 20 - 95 (4) 115 - 120 157. Spiracles found in cockroach are [MAHE ‘05] (1) 2 pairs in thorax and 10 pair in abdomen (2) 2 pairs in thorax and 6 pairs in abdomen (3) 2 pairs in thorax and 8 paris in abdomen (4) 2 pairs in thorax and 4 pairs in abdomen. 158. Blood of earthworm is [Orissa ‘05] (1) red is colour, due to dissolved haemoglobin in plasma (2) red in colour, due to dissolved haemoglobin in corpuscles (3) blue in colour, due to dissolved haemocyanin in plasma (4) blue in colour, due to dissolved haemocyanin in corpuscles. 159. Conglobate gland is present in [Orissa ‘05] (1) male cockraoch (2) female cockroach (3) earthworm (4) Hydra 160. In earthworm the dorsal wall of the intestine from the 26th segment to 95th segment forms a median internal fold called [Kerala ‘05] (1) trochophore (2) typhlosole (3) clitellum (4) trachea

319

161. The diagram represents the reproductive organ of male cockroach. Choose the correct combination of labelling [Kerala ‘05]

C

A B D

162.

163. 164. 165.

166.

167.

168.

169.

(1) A – 8th sternum, B - anal cercus, C - 10th tergum, D anal style (2) A - 10th tergum, B - anal cercus, C - anal style, D - 8th sternum (3) A - anal style, B - anal cercus, C - 10th tergum, D- 8th sternum (4) A - anal cercus, B - 8th sternum, C - 10th tergum. D - anal style. Chloragogen cells resemble the following in function [CPMT ‘05] (1) collared cells (2) flame cells (3) plasma cells (4) mesophyll cells Gizzard of cockroach is a part of [Haryana ‘05] (1) respiratory system (2) digestive system (3) immune system (4) circulatory system In earthworm, fertilization occurs in [CPMT ‘05] (1) ovary (2) oviduct (3) cocoon (4) vasa efferentia The following are associated with Pheretima. Match them [EAMCET ‘05] List I List II 1. Yellow cells A. Primardial germ cells 2. Oval sphinctered pores B. Totipotent 3. Basal cells C. Deamination 4. Parietal layer D. The septum between 14/15 (1) 1-C, 2-D, 3-B, 4-A (2) 1-C, 2-B, 3-D, 4-A (3) 1-C, 2-A, 3-B, 4-D (4) 1-D, 2-A, 3-B, 4-C The number of pairs of valves in lateral oesophageal hearts of pheretima is (1) 1 (2) 2 [EAMCET ‘05] (3) 3 (4) 4 The gland whose secretion facilitates the attachment of two earthworms during Copulation is loacted in the segment : [EAMCET ‘05] (1) 14th (2) 18th (3) 19th (4) 22nd The number of segments on the anal cerci of cockroach is [EAMCET ‘05] (1) 12 (2) 15 (3) 18 (4) 10 Tendons and ligaments are [CPMT ‘03; BHU ‘06] (1) nerve tissue (2) epithelial tissue (3) muscular tissue (4) fibrous connective tissue

320 170. The largest gland of human body is [BHU ‘06] (1) Thyroid (2) Pituitary (3) Pancreas (4) Liver 171. Areolar connective tissue joins [CBSE ‘06] (1) integument with muscles (2) bones with muscles (3) bones with bones (4) fat body with muscles 172. Mast cells secrete [CBSE ‘06] (1) Myoglobin (2) Histamine (3) Hemoglobin (4) Hippurin 173. People living at sea level have around 5 million RBC per cubic millimeter of their blood whereas those living at an altitude of 54 00 metres have around 8 million. This is because at high altitude [CBSE ‘06] (1) atmospheric O2 level is less and hence more RBCs are needed to absorb the required amount of O2 to survive (2) there is more UV radiation which enhances RBC production (3) people eat more nutritive food, therefore more RBCs are formed (4) people get pollution - free air to breathe and more oxygen is available 174. In which of the following disorders, blood has a defective haemoglobin? [KCET ‘06] (1) haemophilia (2) haematuria (3) haematoma (4) sickle cell anaemia 175. The type of epithelial cells which line inner surface of fallopian tubes, bronchioles and small bronchi are known as [AIIMS’06] (1) squamous epithelium (2) columnar epithelium (3) ciliated epithelium (4) cubical epithelium 176. Which one of the following pairs of the kind of cells and their secretion is correctly matched? [AIIMS’06] (1) oxyntic cells—a secretion with pH between 2.0 and 3.0 (2) alpha cells of islets of Langerhans—secretion that decreases blood sugar level (3) kupffer cell—a digestive enzyme that hydrolyses nucleic acids (4) sebaceous glands—a secretion that evaporates for cooling 177. Which of the following is secreted by mast cell? (1) histamine (2) heparin [BHU’06] (3) serotonin (4) all of these 178. Kupffer cells are present in (1) Liver (2) small intestine (3) Pancreas (4) Thyroid gland 179. In rabbit, end of a long bone is connected to another by [BHU’06] (1) tendon (2) ligaments (3) muscle (4) cartilage 180. Which of the following is a transparent tissue? [BHU’06] (1) tendon (2) fibrous cortilage (3) hyaline cartilage (4) all of these 181. Which leucocyte releases heparin and histamine in the blood? [Kerala’06] (1) eosinophil (2) basophil (3) neutrophil (4) lymphocytes

BIOLOGY 182. Graveyard of blood is [AMU’06] (1) spleen (2) liver (3) kidney (4) thymus 183. Sickle cell anaemia is caused due to substitution of [HPMT’06] (1) valine at 6th position at β chain of Hb (2) glutamic acid at 6th position in β chain of Hb by valine (3) glutamic acid at 6th position in α chain of Hb (4) valine at 6th position in β chain of Hb by glutamic acid 184. The largest lymph organ of the body is [JK’06] (1) the cervical node (2) the spleen (3) the axillary node (4) inguinal node 185. Liver is able to manufacture vitamin [Orissa’06] (1) A (2) B (3) K (4) D 186. Spleen is referred to as [Orissa’06] (1) temporary endocrine gland (2) grave yard of RBC (3) largest gland (4) store house of WBC 187. Pernicious anaemia is due to [Orissa’06] (1) Low RBC count (2) death of WBC (3) defective RBC maturation (4) destruction of young RBC 188. Concentration of glucose in blood is [Orissa’06] (1) 0.5% (2) 2% (3) 0.1% (4) 8% 189. Liver and pancreas of frog and rabbit are derived from [CPMT’06] (1) ectoderm (2) mesodern (3) endodern (4) both (2) and (3) 190. Match the following simple epithelia tissues in column I with their occurrence in column II and choose the correct combination from the options given. [Kerala’06] Column I Column II a. squamous 1. intestinal glands b. cuboidal 2. trachea c. columnar 3. ovary d. ciliated 4. blood vessels e. pseudo stratified 5. bronchioles (1) a–1,. b–2, c–4, d–3, e–5 (2) a–5,. b–4, c–2, d–1, e–3 (3) a–4,. b–5, c–1, d–2, e–3 (4) a–4,. b–3, c–1, d–5, e–2 191. Match the following [Kerala’06] a. neutrophil 1. single large necleus b. eosinophil 2. 2 to 3 tobed nucleus c. basophil 3. kindney shaped nucleus d. lymphocyte 4. 2 to 7 lobed nucleus e. monocyte 5. bilobed nucleus (1) a–4,. b–1, c–3, d–5, e–2 (2) a–2,. b–5, c–1, d–4, e–3 (3) a–4,. b–5, c–2, d–1, e–3 (4) a–2,. b–4, c–5, d–3, e–1

ANIMAL TISSUES (HISTOLOGY) & COCKROACH, EARTHWORM AND FROG 192. In the given diagram, parts labelled as ‘a’, ‘b’, ‘c’, ‘d’, and ‘e, respectively represent [Kerala’06] e c a b d

193.

194.

195.

196.

197.

198.

199.

(1) stratum granulosum, sweat gland, stratum germinativum, sebaceous gland and stratum corneum. (2) stratum granulosum, sebaceous gland, stratum germinativum, sweat gland and stratum corneum. (3) stratum germinativum, sweat gland, stratum lucidium, sebaceous gland and stratum ocrneum. (4) stratum germinativum, sebaceous gland, stratum lucidium, sweat gland and stratum corneum. larger and fragile RBC with less haemoglobin is due to the deficiency of [Kerala’06] (1) Castle’s intrinsic factor (2) factor III (3) Hageman factor (4) cephalin In earthworm, female genital opening is present in the segment [CPMT 2000; EAMCET ‘01; BHU ‘06] (1) 10 (2) 13 (3) 14 (4) 18 In cockroach alary muscles are associated with [AMU ‘93; CPMT ‘94; HPMT ‘06] (1) Heart & blood circulation (2) Trachae & spiracles (3) Wings and locomotion (4) Feeding and vision Tadpoles of frog can be made to grow as giant sized tadpoles, if they are [AIIMS’06] (1) administered antithyroid substance like thiourea (2) administered large amounts of thyroxine (3) reared on a diet rich in egg yolk (4) reared on a diet rich in both egg yolk and glucose Which of the following can be absorbed by hepatic caeca? [GCET’06] (1) glucose and amino acid (2) glucose and lipid (3) lipid (4) glucose In frog heart, there are cardiac muscles which consist of fibres called [BHU’06] (1) Purkinje fibres (2) myonemes (3) telodendria (4) columnae carnae In Pheretima, septa are absent between which segments? [BHU’06] (1) 3/4 and 9/10 (2) 4/5 and 8/9 (3) 5/ 6 and 7/8 (4) 7/8 and 6/7

321

200. In earthworm, neurons are [BHU’06] (1) sensory (2) associated (3) motor (4) all of these 201. In cockroach, larval and nymphal characters are maintained by [BHU’06] (1) ecdysone (2) salivary glands (3) parotid gland (4) juvenile hormone 202. Which structure is absent in male cockroach? [AMU’06] (1) labium (2) phallomeres (3) spermatheca (4) none of these 203. The typhlosole in earthworm intestine is found is [HPMT’06] (1) 30 - 100 segments (2) 21 - 95 segments (3) 20 - 80 segments (4) 26 - 95 segments 204. Spending the dry hot period in an inactive state by an animal is [HPMT’06] (1) camouflage (2) hibernation (3) aestivation (4) mullerian mimicry 205. Parotid glands are located below [JK’06] (1) the floor of the mouth (2) the external acoustic meatus (3) the tongue (4) the eye 206. During hibernation frog respires through (1) gills (2) lungs [Orissa’06] (3) integument (4) tympanum 207. Incorrect statement about earthworm is [CPMT’06] (1) to help in cross fertilization, ovaries mature earlier (2) female genital pore is present on 14th segment (3) male genital papilla occur on 17th & 19th segment (4) metameric segmentation present 208. Metamorphosis in tadpole can be increased by treatment of water with [CPMT’06] (1) NaCl (2) thyroxine (3) iodine (4) GH 209. Circulatory system in earthworm is [CPMT’06] (1) open type with haemoglobin in plasma (2) closed type with haemoglobin in RBC’s (3) open type with haemoglobin in RBC’s (4) closed type with haemoglobin in plasma 210. Select the false statement [Kerala’06] (1) in rats the teeth are heterodont and thecodont (2) in female rat, the urinary and genital apertures are located above anus (3) in female rats, six pairs of nipples are present on the ventral surface of the trunk (4) in rats, 12 pairs of cranial nerves and 33 pairs of spinal nerves are present 211. Male cockroach and female cockroach can be differentiated by [CPMT’06] (1) ocelli (2) anal cerci (3) anal styles (4) both (2) and (3) 212. Bidder’s canal is present in [CPMT’06] (1) female frog (2) male frog (3) female rabbit (4) male rabbit

322 213. In the 4th, 5th and 6th segments of earthworm, lying above pharyngeal mass and connected with pharyngeal glands are found small, red coloured follicular bodies called [Kerala’06] (1) septal glands (2) blood glands (3) salivary glands (4) nephridia 214. The correct sequence of arrangements of segments in the leg of cockroach is [Kerala’06] (1) tibia, trochanter, femur, tarsus and coxa (2) trochanter, coxa, tibia, femur and tarsus (3) coxa, femur, trochanter, tibia and tarsus (4) coxa, trochanter, femur, tibia and tarsus 215. Which one of the following mammalian cells is not capable of metabolising glucose to carbon-dioxide aerobically? [CBSE’07] (1) Red blood cells (2) White blood cells (3) Unstriated muscle cells (4) Liver cells 216. In which one of the following preparation are you likely to come across cell junctions most frequently? [CBSE’07] (1) Hyaline cartilage (2) Ciliated apithelium (3) thrombocytes (4) Tendon 217. Which one of the following pairs of structures distinguishes a nerve cell from other types of cell? [CBSE’07] (1) Nucleus and mitochondria (2) Perikaryon and dendrites (3) Vaculoes and fibres (4) Flagellum and medullary sheath 218. Which type of white blood cells are concerned with the release of histamine and the natural anticoagulant heparin? [CBSE’08] (1) Monocytes (2) Neutrophils (3) Basophils (4) Eosinophils 219. The most active phagocytic white blood cells are: (1) Neutrophils and monocytes (2) Neutrophils and eosinophils (3) Lymphocytes and macrophages (4) Eosinophils and lymphocytes 220. The haemoglobin in a human foetus [CBSE’08] (1) has higher affinity for oxygen than that of an adult (2) has a lower affinity for oxygen than that of the adult (3) its affinity of oxygen is the same as that of an adult (4) has only 2 protein subunits instead of 4 221. There is no DNA in [CBSE’09] (1) Hair root (2) An enucleated ovum (3) Mature RBCs (4) A mature spermatozoan 222. Which one of the following is correct pairing of a body part and the kind of muscle tissue that moves it? [CBSE’09] (1) Iris - Involuntary smooth muscle (2) Heart wall - Involuntary unstriated muscle (3) Biceps of upper arm - Smooth muscle fibres (4) Abdominal wall - Smooth muscle 223. The cell junction called tight, adhering and gap junctions are found in [CBSE’09] (1) Neural tissue (2) Muscular tissue (3) Connective tissue (4) Epithelial tissue 224. Compared of blood our lymph has : [CBSE’09] (1) more RBCs and less WBCs (2) no plasma (3) plasma without protein (4) more WBCs and no RBCs

BIOLOGY 225. Globulins contained in human blood plasma are primarily involved in : [CBSE’09] (1) clotting of blood (2) defence mechanisms of body (3) osmotic balance of body fluids (4) oxygen transport in the blood 226. Sickle cell anemia is [CBSE’09] (1) Characterized by elongated sickle like RBCs with a nucleus (2) an autosomal linked dominant trait (3) caused by substitution of valine by glutamic acid in the beta globin chain of haemoglobin (4) caused by a change in a single base pair of DNA 227. The kind of tissue that forms the supportive structure in our pinna (extranal ears) is also found in [CBSE’09] (1) tip of the nose (2) vertebrae (3) nails (4) ear ossicles 228. The epithelial tissue present of the inner surface of bronchioles and fallopian tubes is [CBSE’09] (1) Squamous (2) Cuboidal (3) Glandular (4) Ciliated 229. Which two of the following changes (a-d) usually tend to occur in the plain dwellers when they move to high altitudes (3,500 m or more)? (a) Increase in red blood cell size. (b) Increase in red blood cell production. (c) Increase breathing rate. (d) Increase in thrombocyte count 230. Which one of the following is the true description about an animal concerned ? [CBSE’08] (1) Cockroach - 10 pairs of spiracles (2 pairs on throax and 8 pairs on abdomen) (2) Earthworm - The alimentary canal consists of a sequence of pharynx, oesophagus, stomach, gizzard and intestine (3) Frog - Body divisible into three regions -head, neck and trunk (4) Rat- Left kidney is slightly higher in position than the right one 231. Earthworms have no skeleton but during burrowing, the anterior end becomes turgid and acts as a hydraulic skeleton. It is due to [CBSE’08] (1) Setae (2) Coelomic fluid (3) Blood (4) Gut peristalsis 232. If a live earthworm is pricked with a needle on its outer surface without damaging its gut the fluid that comes out is : [CBSE’09] (1) slimy mucus (2) excretory fluid (3) coelomic fluid (4) haemolymph 233. Which one of the following correctly describes the location of some body parts in earthworm Pheretima? [CBSE’09] (1) Two pairs of tastes in 10th and 11th segments. (2) Two pairs of accessory glands in 16-18 segments. (3) Four pairs of spermathecae in 4-7 segments. (4) One pair of ovaries attached at intersegmental septum of 14th and 15th segments Changes occuring are : [CBSE’10] (1) (a) and (b) (2) (b) and (c) (3) (c) and (d) (4) (a) and (d)

ANIMAL TISSUES (HISTOLOGY) & COCKROACH, EARTHWORM AND FROG 234. The kind of epithelium which forms the inner walls of blood vessels is : [CBSE’10] (1) squamous epithelium (2) cuboidal epithelium (3) columnar epithelium (4) ciliated columnar epithelium 235. Mature erythrocytes cannot utilize glucose because they lack [DPMT’ 10] (1) Golgi complex (2) Enzymes (3) Mitochondria (4) Nucleus 236. Hyaline cartilage does not have [DPMT’ 10] (1) Fibres (2) Lacunae (3) Cells (4) Blood capillaries 237. In which one of the following organisms its excretory organs are correctly stated? [CBSE’ 10, Final] (1) Humans - Kidneys, sebaceous glands and tear glands (2) Earthworm - Pharyngeal, integumentary and septal nephridia (3) Cockroach - Malpighian tubules and enteric caeca (4) Frog - Kidneys, skin and buccal epithelium 238. The ciliated columnar epithelial cells in humans are known to occur in [CBSE’ 11] (1) Fallopian tubes and urethra (2) Eustachian tube and stomach lining (3) Bronchioles and Fallopian tubes (4) Bile duct and oesophagus 239. The cells lining the blood vessels belong to the category of [CBSE’ 11, Final] (1) Columnar epithelium (2) Connective tissue (3) Smooth muscle tissue (4) Squamous epithelium 240. The type of muscles present in our [CBSE’ 11, Final] (1) Thigh are striated and voluntary (2) Upper arm are smooth and fusiform in shape (3) Heart are involuntary and unstriated (4) Intestine are striated and involuntary 241. Graveyard of RBCs is [DPMT’ 11] (1) Liver (2) Spleen (3) Kidney (4) Lymph glands 242. Blood cells involved in inflammatory reactions are [DPMT’ 11] (1) Basophils (2) Neutrophils (3) Eosinophils (4) Monocytes 243. Cardiac muscles are [WB-JEE’ 11] (1) Striated and voluntary (2) Striated and involuntary (3) Smooth and voluntary (4) Smooth and involuntary 244. Which one of the following cells is not a phagocytic cell ? [WB-JEE’ 11] (1) Macrophage (2) Monocyte (3) Neutrophil (4) Basophil 245. Which of the following organs in earthworm neutralizes humic acid present in humus? [DPMT’ 11] (1) Typhosole (2) Calciferous glands (3) Intestinal caecum (4) Gizzard

323

246. Fertilized eggs of P. americana are encased in [DPMT’ 11] (1) Ootheca (2) Cocoon (3) Genital chamber (4) Phallomere 247. One very special feature in the earthworm pheretima is that [CBSE’ 11] (1) It has a long dorsal tubular heart (2) Fertilisation of eggs occurs inside the body (3) The typhlosole greatly increases the effective absorption area of the digested food in the intestine (4) The S-shaped setae embedded in the integument are the defensive weapons used against the enemies 248. Which of the following is correctly stated as happens in the common cockroach? [CBSE’ 11] (1) The food is ground by mandibles and gizzard (2) Malpighian tubules are excretory organ projecting out from the colon (3) Oxygen is transported by haemoglobin of blood (4) Nitrogenous excretory product is urea 249. Which one of the following structures in Pheretima is correctly matched with its function? [CBSE’ 11, Final] (1) Setae-defence against predators (2) Typhlosole - storage of extra nutrients (3) Clitellum - secretes cocoon (4) Gizzard - absorbs digested food 250. The breakdown of detritus into smaller particles by earthworm is a process called [CBSE’ 11, Final] (1) Mineralisation (2) Catabolism (3) Humification (4) Fragmentation 251. Frogs differ from humans in possessing [CBSE’ 11, Final] (1) Nucleated red blood cells (2) Thyroid as well as parathyroid (3) Paired cerebral hemispheres (4) Hepatic portal system 252. Consider the following four statements (A-D) related to the common frog, Rana tigrina, and select the correct option stating which ones are true (T) and which ones are false (F). [CBSE’ 11, Final] Statements: (A) One dry land it would die due to lack of O2 if its mouth is forcibly kept closed for a few days. (B) It has four chambered heart. (C) On dry land it turns uricotelic from ureotelic. (D) Its life history is carried out in pond water. Options : (1) A-F; B-F; C-T; D-T (2) A-F; B-T; C-T; D-F (3) A-T; B-F; C-F; D-T (4) A-T; B-T; C-F; D-F 253. People who have migrated from the planes to an area adjoining Rohtang Pass about six months back [CBSE’ 12] (1) Suffer from altitude sickness with symptoms like nausea, fatigue, etc (2) Have the usual RBC count but their haemoglobin has very high binding affinity to O2 (3) Have more RBCs and their haemoglobin has a lower binding affinity to O2 (4) Are not physically fit to play games like football

324

BIOLOGY

254. Select the correct statement from the ones given below with respect to Periplaneta americana [CBSE’ 12] (1) There are 16 very long Malpighian tubules present at the junctions of midgut and hindgut (2) Grinding of food is carried out only by the mouth parts (3) Nervous system located dorsally, consists of segmentally arranged ganglia joined by a pair of longitudinal connectives (4) Males bear a pair of short thread like anal styles 255. Pheretima and its close relatives derive nourishment from [CBSE’ 12] (1) Soil insects (2) Small pieces of fresh fallen leaves of maize etc (3) Sugarcane roots (4) Decaying fallen leaves and soil organic matter 256. Compared to those of humans, the erythrocytes in frog are [CBSE’ 12] (1) Very much smaller and fewer (2) Nucleated and without haemoglobin (3) Without nucleus but with haemoglobin (4) Nucleated and with haemoglobin 257. Compared to those of humans, the erythrocytes in frog are [2012] (a) Without nucleus but with haemoglobin (b) nucleated and with haemoglobin (c) very much smaller and fewer (d) nucleated and without haemoglobin. 258. Select the correct statement from the ones given below with respect to Periplaneta americana. [2012]

260. The supportive skeletal structures in the human external ears and in the nose tip are examples of [2012M] (a) ligament (b) areolar tissue (c) bone (d) cartilage 261. The four sketches (1, 2, 3 and 4) given below, represent four different types of animal tissues. Which one of these is correctly identified in the options given, along with its correct location and function? [2012M]

(a) Nervous system located dorsally, consists of segmentally arranged ganglia joined by a pair of longitudinal connectives.

262. What external changes are visible after the last moult of a cockroach nymph? [AIPMT (NEET)’13] (1) Mandibles become harder (2) Anal cerci develop (3) Both fore and hind wings develop (4) Labium develops 263. Histology deals with the study of: [AMU’13] (1) Structures which can be discerned with naked eye (2) Tissues (3) Cells (4) Changes in form and structure during developemt 264. Originating in bone marrow, circulating in blood for 1-2 days, migrating to connective tissue and forming macrophages, is a characteristic of: [AMU’13] (1) Eosinophils (2) Basophils (3) Monocytes (4) Lymphocytes 265. In cockroach the flow of haemolymph is: [AMU’13] (1) Heart- head haemocoel- perivisceral sinus- pericardial sinus- ostia- heart (2) Heart- pericardial sinus- head haemocoel- perivisceral sinus- ostia- heart (3) Heart- head haemocoel- perivisceral sinus- ostiapericardial sinus- heart (4) Heart- ostia- perivisceral sinus- pericardial sinus- head haemocoel- heart

(b) Males bear a pair of short thread like anal styles. (c) There are 16 very long Malpighian tubules present at the junctions of midgut and hindgut. (d) Grinding of food is carried out only by the mouth parts. 259. Given below is the diagrammatic sketch of a certain type of connective tissue. Identify the parts labeled A, B, C and D, and select the correct answer from the given option. [2012M]

(a) (b) (c) (d)

Part-A

Part-B

Part-C

Part - D

Macro-

Fibro-

Collagen

Mast cells

phage

blast

fibres

Mast

Macro-

Fibroblast

cell

phage

Macro-

Collagen

phage

fibres

Mast

Collagen

cell

fibres

Collagen fibres

Fibroblast

Mast cell

Fibroblast

Macrophage

(1)

(2)

(3)

(4)

Tissue

Location Function

(a)

(2) Glandular epithelium

Intestine

Secretion

(b)

(3) Collagen fibres Cartilage Attach skeletal muscles to bones

(c)

(4) Smooth muscle Heart tissue

(d)

(1) Columnar epithelium

Heart contraction

Nephron Secretion and absorption

ANIMAL TISSUES (HISTOLOGY) & COCKROACH, EARTHWORM AND FROG 266. Identify the tissue shown in the diagram and match with its characteristcs and its location [NEET Kar. 2013]

(a) Skeletal muscle, shows striations and closely attached with the bones of the limbs (b) Smooth muscles, show branching, found in the walls of the heart (c) Cardiac muscles, unbranched muscles, found in the walls of the heart (d) Striated muscles, tapering at both-ends, attached with the bones of the ribs 267. Select the correct option with respect to cockroaches [NEET Kar. 2013] (a) The fore wings are tegmina which are used in flight (b) Malpighian tubules convert nitrogenous wastes into urea (c) Males bear short anal styles not present in females (d) Nervous system comprises of a dorsal nerve cord and ten pairs of ganglione 268. Histology deals with the study of: [AMU’13] (1) Structures which can be discerned with naked eye (2) Tissues

269.

270.

271.

272.

325

(3) Cells (4) Changes in form and structure during developemt Originating in bone marrow, circulating in blood for 1-2 days, migrating to connective tissue and forming macrophages, is a characteristic of: [AMU’13] (1) Eosinophils (2) Basophils (3) Monocytes (4) Lymphocytes In cockroach the flow of haemolymph is: [AMU’13] (1) Heart- head haemocoel- perivisceral sinus- pericardial sinus- ostia- heart (2) Heart- pericardial sinus- head haemocoel- perivisceral sinus- ostia- heart (3) Heart- head haemocoel- perivisceral sinus- ostiapericardial sinus- heart (4) Heart- ostia- perivisceral sinus- pericardial sinus- head haemocoel- heart Choose the correctly matched pair: [AIPMT’14] (1) Tendon- specialized connective tissue (2) Adipose tissue- Dense connective tissue (3) Areolar tissue- Loose connective tissue (4) Cartilage- Loose connective tissue Choose the correctly matched pair: [AIPMT’14] (1) Inner lining of salivary ducts- ciliated epithelium (2) Moist surface of buccal cavity- glandular epithelium (3) Tubular part of nephrons- cuboidal epithelium (4) Inner surface of bronchioles- squamous epithelium

326

BIOLOGY

EXERCISE - 3 | Test Yourself 1.

2.

3.

4.

On histological basis mark the odd one out

9.

(1) Bone

(2) Tendon.

(1) Casein

(2) Ossein

(3) Muscle

(4) Blood

(3) Chondroitin

(4) Chondrin

Which of the following is the example of mucous connective tissue? (1) Peyer’s patches

(2) Cock’s comb

(3) Hump ofc:amel

(4) All of these

Which of the following are bone forming cells? (1) Osteocytes

(2) Osteoblasts

(3) Osteoclasts

(4) None of these

Sweat (Sudorific) glands in mammals are

10.

11.

12.

6.

(4) Endometrium

The term red pulp and white pulp are associated with (1) Spleen

(2) Liver

(3) Thymus

(4) None of these

Lamina propria in the gut is the part of

(4) Tunica adventitia 13.

Which of the cartilage is different from rest of the other (1) Cartilage at tip of nose

(2) Endothelium

(2) Cartilage in the wall of Eustachian tube

(3) Muscular tissue

(4) Blood

(3) Cartilage in ear pinna

In order to study the efficiency of stereocillia one can refer to

(4) Cartilage at nasal septum 14.

(2) Cartilagenous bone

(3) Epididymis

(3) Endochondral bone

(4) All of the above Epithelium present in cornea & oesophagus is (1) Glandular

(4) Replacing bone 15.

(2) Longitudinal canals in compact bone

(3) Stratified columnar

(3) Transverse canals in compact bone

(4) Ciliated epithelium (1) Follicular epithelium of thyroid gland

Volkman’s canals in mammalian bones are (1) Present in cancellous part

(2) Stratified squamous

Which epithelial layer is mesodermal in origin?

Which one of the bone is different from the rest (1) Investing bone

(2) Ependymal epithelium

8.

(3) Ependyma

(1) Areolar tissue

(1) Fallopian tube

7.

(2) Peritoneum

(3) Tunica mucosa

(3) Simple and Coiled Which of the following connective tissue is devoid of fibres?

(1) Endothelium

(2) Tunica muscularis

(2) Simple and Alveolar (4) Compound and Coiled

The epithelial lining of uterus is called

(1) Tunica submucosa

(1) Compound and Tubular

5.

Sugar in the matrix of hyaline cartilage is

(4) None of these 16.

What is true about leucocytes?

(2) Stratum Malpighii

(1) Their sudden fall in number is indicative of blood cancer

(3) Lining of sweat glands

(2) They are produced in thymus

(4) None of these

(3) They can squeeze out through the capillary walls (4) They are enucleated

ANIMAL TISSUES (HISTOLOGY) & COCKROACH, EARTHWORM AND FROG 17.

Stratum germinativum in the skin consists of

(3) Covering formed by Schwann cells

(1) Simple columnar epithelium

(4) Connective tissue covering of nerve fasciculus

(2) Stratified squamous epithelium (3)

26.

Simple squamous epithelium

(4) None of these’ 18.

Newly born child is more resistant to cold because of the presence of (1) Thick dermis

(2) Blubber

(3) Brown fat

(4) White fat

19. . Lack of blood supply and presence of the noncellular basement membrane are the characteristics of the

27.

28.

(1) Muscular tissue (2) Fluid connective tissue

20.

21.

29.

(3) Ribosomes

(4) All of these

Pseudostratified epithelium is always (1) Double layered

(2) Multilayered

(3) Single layered

(4) None of the above

The vascular connective tissue contains no (1) Fibres

(2) Matrix

(3) Both (1) and (2)

(4) Cells

Bipolar neurons (2) Have two dendrites

Blood brain barrier is made up of

(3) Are maximum in the brain

(1) Astrocytes

(2) Oligodendrocytes

(4). Are found in retina

(3) Microglia

(4) Neurons

30.

Mark the correct statement

All are the functions of liver except

(1) Blood can clot but plasma cannot

(1) Deamination and urea formation

(2) Plasma can clot but lymph cannot

(2) Synthesis of Gamma-globulins

(3) Lymph can clot but serum cannot

(3) Synthesis of Heparin

(4) Plasma and Serum both cannot clot 31.

Both the epithelial lining of the following set are similar in nature

RBC-count (approximately 5 million in human blood) is taken per (1) Decilitre

(2) Cubic milimetre

(3) Cubic centimetre (4) Litre of blood 32.

At higher altitudes

.

(3) Endocardial epithelium and.eye-lens lining

(1) The number and size of erythrocytes increases

(4) All of these

(2) Only size of erythrocytes increases’

.

Which epithelial layer does not have basement membrane

(3) Only the number of erythrocytes increases

(1) Transitional

(2) Stratified

(3) Pseudost~atified

(4) Sensory

(4) Either the number or the size of erythrocytes increases

The erythrocytes resemble mature platelets as both

33.

(1) Help in blood clotting (2) Are produced from the same mother cells (3) Are of the same size (4) Are non- nucleated 25.

(2) Mitochondria

(4) Nervous tissue

(2) Buccal epithelium and PCT -layer

24.

(1) Centrosome

(1) Are present in dorsal root ganglion of spinal cord

(1) Alveolar epithelium and vaginal epithelium

23.

Following organelle/organelles is/are absent in neurons .

(3) Epithelial tissue

(4) Synthesis of Bile 22.

327

Neurilemma is the name for (1) Plasma membrane of Axon (2) Coating formed by mylein sheath

34.

Young and non-nucleated RBC is called (1) Normoblast

(2) Erythroblast

(3) Erythrocyte

(4) Reticulocyte

Diploic bone is (1) Spongy bone found in ribs (2) Spongy bone found in skull (3) Shaft of long bone. (4) All of the above

328 35.

BIOLOGY Lymphocytes are seen in large numbers at the site of inflammation because :

44.

(1) Their function is phagocytic

(1) Collagen fibres.

(2) Elastin fibres

(2) Their function is to form and carry antibodies

(3) Reticular fibres

(4) None of these

(3) They prevent clotting of blood at that site

45.

(4) All of the above 36.

The amount of haemoglobin in a healthy person is approximately. (1) 15 g/l00 ml of blood

46.

40.

41.

Heparin, an anticoagulant present in human blood, is chemically (1) Glycoprotein

(2) Nucleoprotein

(3) Protein

(4) Carbohydrate

Which of the following term is not related to RBCs? (1) Rouleaux

(2) Diapedesis

(3) Crenation

(4) All of these

Among the followings which blood element is more numerous in human? (1) Lymphocyte

(2) Eosinophil

(3) Monocyte

(4) Basophil

(4) Mast cells.

The longitudinal channels in the long bones are:

(4) Vertebro-arterial canals. 47.

48.

49.

Which of the following tissue has minimum intercellular material: (1) Epithelial tissue

(2) Nervous tissue

(3) Muscular tissue

(4) Blood

According to the latest theory which one of the following clotting factor has been discarded (1) Accelerin

(2) Proconvertin

(3) proaccelerin

(4) PTC factor

The fine branches of vagus nerve within the wall of intestine to control peristalsis, form (1) Meissner’s plexus (2) Auerbach plexus

(1) Basophils

(2) Acidophils

(4) Folds of Kerckring

(3) Lymphocytes

(4) Neutrophils.

(3) Markel’s discs 50.

Match the column I with column II and mark the answer Column B

The camel’s hump is composed ofa tissue which provides water when oxidized. It is: (1) Skeletal tissue

(2) Areolar tissue

(3) Adipose tissue

(4) Muscular tissue.

(A) Reticulocyte

(1) Clotting

(B) Vitamin K

(2) RBC

(C) Calcium ion

(3) Bone marrow

(1) Ciliated epithelium

(D) Erythropoesis

(4) Muscle contraction

(2) Columnar epithelium

51.

(2) A - 1, B - 3, C - 2, D - 4 (3) A - 2, B - 2, C - 3, D - 1

(4) Stratified epithelium 52.

(4) A - 3, B - 4, C - 2, D - 1 Best source to obtain areolar connective tissue for histology is (1) Periosteum

(2) Perimycium

(3) Perichondrium

(4) Epimycium

The term histology was introduced by (1) Ruysch

(2) Bichat

(3) Mayer

(4) Marcello Malpighii

Urethra, Vagina and Oesophagus have a common inner lining of:

(3) Cuboidal epithelium

(1) A - 2, B - 1, C - 4, D - 3

43.

(3) Fibroblasts

In persons, suffering from allergies and parasitic infections, the number of the following blood elements rises.

Column A

42.

(2) Histiocytes

(3) Eustachian canals

(4) 15 mg/ml of blood

39.

(1) Macrophages

(2) Haversian canals

(3) 15 g/litre of blood

38.

The following cells of Areolar connective tissue are modified to form adipocytes

(1) Volkmann’s canals

(2) 15 mg/l00 ml of blood

37.

Which of the following type of fibres are most resistant to chemicals

53.

Haversian system is present in: (1) Ilium of frog

(2) Radius of Rabbit

(3) Femur of lizard

(4) Humerus of bird.

If a tendon gets ossified to form bone, such type of bone is called: (1) Membranous bone (2) Sesamoid bone (3) Dermal bone

54.

(4) Replacing bone

Glands in a vertebrate body originate from: (1) Ectoderm only (2) Mesoderm only

ANIMAL TISSUES (HISTOLOGY) & COCKROACH, EARTHWORM AND FROG

55.

(3) Ectoderm or endoderm

C.

Chief cells

III. HCI

(4) Ectoderm, Mesoderm or Endoderm

D.

Hepatic cells

IV. Proenzymes

Erythrocytes

(1) A-II, B-1, C-IV, D-III

(1) Produce erythropoietin

(2) A-III, B-II, C-I, D-IV

(2) Carry out glycolysis by means of TCA cycle

(3) A-III, B-1, C-IV, D-II

(3) Are the smallest blood elements

(4) A-I, B-II, C-IlI, D-IV

(4) Use ATP as energy source 56.

58.

66.

(1) Fibrinogen

(2) Lymphocytes

(1) Connective tissue (2) Epithelial tissue

(3) Both of these

(4) None of these

The blood is

.

(4) Muscular tissue.

.

Increase in the number of RBCs is called (1) Erythropoesis

(2) Haemopoesis

(3) Haematocrit

(4) None of these

Anaemia, due to a defect in a polypeptide chain of globin is called (1) Sickle cell anaemia

67.

(1) Ectodermal in origin (2) Mesodermal in origin (3) Ecto- and mesodermal in origin (4) Endodermal in origin 68.

(2) Megaloblastic anaemia (3) Thalassaemia

69.

(4) Pernicious anaemia 59.

60.

(1) 2

(2) 3

(3) 4

(4) 5

Both the structure of which set have similar type of epithelial lining

70.

(4) 12 and 13

Dorsal blood vessel in earthworm is

How many testes are present in earthworm

(1) Small intestine and Oesophagus

(1) One pair

(2) Two pairs

(2) Bowman’s capsule and Alveoli

(3) Four pairs

(4) Single

71.

Oxygen is circulated to various tissues of earthworm by (1) Plasma

Nissl’s granules are present in

(2) Plasma and blood corpuscles

(1) Glia cells

(2) Axon

(3) Tracheal system, as haemoglobin is absent

(3) Cyton

(4) Both (2) and (3)

(4) None of these

Gastric glands are

72.

Blood from seminal vesicle in earthworm is collected by (1) Supra oesophageal vessel (2) Lat. oesophageal vessel

(3) Simple branched tu tubular type

(3) Dorsal vessel

(4) None of these

65.

(3) 6, 7, 8, 9

(4) None of these

(2) Simple branched alveolar type

64.

(2) 17, 19

(3) Collective in first 13 segments

(1) Simple tubular type

63.

(1) 4, 5, 6

(2) Distributive completely

(4) All of these

62.

Accessory glands in earthworm occur in segments

(1) Distributive after 13 segments

The subunits present in haemoglobin are

(3) Salivary duct and Oviduct 61.

The blood differs from plasma in having

Cilia, Flagella and microvilli are associated with the’ (3) Nervous tissue.

57.

329

(4) Subneural vessel

Mark the odd one out (1) Lymphocytes

(2) Basophils

(3) Acidophils

(4) Thrombocytes

73.

As compared to other segments, clitellum has (1) More endonephric nephridia (2) More pharyngeal nephridia

Which blood element has a kidney shaped nucleus

(3) More exonephric nephridia

(1) Reticulocyte

(2) Lymphocyte

(4) None of these

(3) Thrombocyte

(4) Monocyte

Match the cells of column I with column II

74.

Which set is similar in segmental position (1) Male genital pore and genital papillae

Column I

Column II

(2) Blood glands and septal nephridia

A.

Oxyntic cells

I.

Mucus

(3) Anterior loops and testes

B.

Goblet cells

II.

Bile

(4) None of these

330 75.

76.

BIOLOGY Typhlosole in earthworm arises after

85.

(1) Intestinal cecae

(1) Absent

(2) Clitellum

(2) Reduced

(3) 25th segment

(3) Called Hoemocoel

(4) All of these

(4) well developed

What change would have occured, if earthworm had wriggled out of its cocoon through its posterior end, instead of anterior

86.

(1) It would have taken lesser time (2) Cocoon would have remained open

77.

78.

87.

Hepatic caeca in cockroach are present in between

(3) Proventriculus and Mesenteron

(1) Gonopores

(2) Dorsal pores

(4) Oesophagus and Gizzard

(3) Nephridiopores

(4) Spiracles

88.

Which cockroach is most common in India

One of the following is not the characteristic of Leech

(1) Blatta orientalis

(1) Ectoparasite and Sanguivorous

(2) Periplaneta americana

(2) Open blood vascular system

(3) Blattela germanica

(3) Monoecious form

(4) None of these 89.

Gizzard (Proventriculus) in cockroach lies between (1) Oesophagus and stomach

Nephrostome in Holonephridia

(2) Crop and mesenteron (3) Mesenteron and ileum (4) Oesophagus and crop 90.

Parasitic castration in earthworm is caused by (1) Monocystis

(2) Babesia

(3) Eimeria

(4) Trypanosoma

(2) Crystalline cone (3) Corneal facet (4) Pigmented sheath 91.

(2) Last 13 segments

The part of cockroach’s eye, which is comparable to retina of vertebrate’s eye, is (1) Rhabdome

Non-porous septa in earthworm are present in (1) First 13 segments

Ootheca of cockroach contains

(3) Intestinal region

(1) 8-eggs (4 in each row)

(4) Typhlosolar region

(2) 16-eggs (8 in each row)

The number of spiracles in cockroach is

(3) 16 eggs (4 in each row)

(1) Six pairs

(2) 13 (3 + 10) pairs

(4) 8 eggs in a single row

(3) 10 only

(4) 20 only

92.

The term ‘Atrium’ in cockroach is related to

In cockroach, Ecdysone is secreted from

(1) Respiratory system

(1) Corpora cardiaca (2) Prothoracic gland

(2) Circulatory system

(3) Corpora allata 84.

(4) 10th

Coelom in earthworm communicates to exterior through

(4) Opens into supraintestinal excretory duct

83.

(3) 3rd

(2) Mesenteron and Intestine

(3) Opens into septal excretory canal

82.

(2) 2nd

(4) Cocoon would have been emptied

(2) Is absent

81.

(1) 1st

(1) Gizzard and Intestine

(1) Opens into coelom

80.

Which pair of spiracles in cockroach (number from anterior side) is valve-less and lies on dorsal sclerite

(3) Fertilization would not have occured

(4) Trochophore larva in life cycle 79.

In cockroach the true coelom is

(4) None of these

Arrangement of tarsus (S), femur (F), trochanter (T), tibia (B) and coxa (C) in cockroach leg is (1) TCFSB

(2) FTSCB

(3) CTFBS

(4) CFTBS

(3) Reproductive system (4) Compound eye

ANIMAL TISSUES (HISTOLOGY) & COCKROACH, EARTHWORM AND FROG

331

ANSWER KEY 1. 6. 11. 16. 21. 26. 31. 36. 41. 46.

EXERCISE 1 : NCERT BASED QUESTIONS (2) 2. (1) 3. (2) 4. (3) 5. (1) 7. (4) 8. (4) 9. (4) 10. (3) 12. (3) 13. (4) 14. (4) 15. (1) 17. (1) 18. (2) 19. (4) 20. (1) 22. (3) 23. (1) 24. (4) 25. (4) 27. (4) 28. (2) 29. (3) 30. (4) 32. (4) 33. (3) 34. (3) 35. (1) 37. (4) 38. (3) 39. (3) 40. (1) 42. (1) 43. (4) 44. (1) 45. (4)

(3) (3) (3) (4) (2) (4) (1) (4) (4)

EXERCISE 2 : WINDOW TO COMPETITIVE EXAMS 1. 6. 11. 16. 21. 26. 31. 36. 41. 46. 51. 56. 61. 66. 71. 76. 81. 86. 91. 96. 101. 106. 111. 116. 121. 126. 131. 136. 141. 146. 151. 156. 161. 166. 171. 176.

(1) (1) (2) (2) (3) (1) (3) (1) (2) (3) (1) (2) (3) (3) (3) (2) (4) (3) (1) (3) (2) (1) (1) (1) (3) (1) (2) (2) (2) (1) (2) (4) (1) (3) (1) (1)

2. 7. 12. 17. 22. 27. 32. 37. 42. 47. 52. 57. 62. 67. 72. 77. 82. 87. 92. 97. 102. 107. 112. 117. 122. 127. 132. 137. 142. 147. 152. 157. 162. 167. 172. 177.

(1) (4) (3) (2) (4) (3) (4) (4) (1) (1) (4) (4) (2) (4) (4) (1) (4) (2) (4) (1) (1) (1) (3) (3) (1) (2) (1) (4) (1) (4) (2) (3) (2) (3) (2) (4)

3. 8. 13. 18. 23. 28. 33. 38. 43. 48. 53. 58. 63. 68. 73. 78. 83. 88. 93. 98. 103. 108. 113. 118. 123. 128. 133. 138. 143. 148. 153. 158. 163. 168. 173. 178.

(2) (3) (2) (1) (1) (1) (1) (2) (1) (3) (1) (1) (1) (2) (2) (4) (2) (4) (1) (2) (1) (4) (1) (1) (2) (1) (2) (1) (3) (4) (3) (1) (2) (2) (1) (1)

4. 9. 14. 19. 24. 29. 34. 39. 44. 49. 54. 59. 64. 69. 74. 79. 84. 89. 94. 99. 104. 109. 114. 119. 124. 129. 134. 139. 144. 149. 154. 159. 164. 169. 174. 179.

(2) (4) (4) (3) (4) (3) (3) (3) (2) (1) (4) (1) (4) (2) (1) (3) (3) (2) (4) (2) (1) (3) (3) (1) (4) (3) (3) (1) (3) (1) (1) (1) (3) (4) (4) (2)

5. 10. 15. 20. 25. 30. 35. 40. 45. 50. 55. 60. 65. 70. 75. 80. 85. 90. 95. 100. 105. 110. 115. 120. 125. 130. 135. 140. 145. 150. 155. 160. 165. 170. 175. 180.

(4) (3) (1) (4) (3) (3) (1) (2) (2) (1) (3) (2) (2) (1) (2) (3) (2) (3) (4) (2) (4) (3) (1) (1) (3) (2) (3) (1) (3) (4) (3) (2) (1) (4) (3) (3)

181. 186. 191. 196. 201. 206. 211. 216. 221. 226. 231. 236. 241. 246. 251. 256. 261. 266. 271.

(2) (2) (3) (1) (4) (3) (3) (2) (3) (4) (2) (1) (2) (1) (1) (4) (1) (1) (3)

182. 187. 192. 197. 202. 207. 212. 217. 222. 227. 232. 237. 242. 247. 252. 257. 262. 267. 272.

(1) (3) (4) (4) (3) (1) (2) (2) (1) (1) (3) (2) (1) (3) (1) (2) (3) (3) (3)

183. 188. 193. 198. 203. 208. 213. 218. 223. 228. 233. 238. 243. 248. 253. 258. 263. 268.

(2) (3) (1) (1) (4) (3) (2) (3) (4) (4) (1) (3) (2) (1) (3) (2) (2) (2)

184. 189. 194. 199. 204. 209. 214. 219. 224. 229. 234. 239. 244. 249. 254. 259. 264. 269.

(2) (3) (3) (1) (3) (4) (4) (1) (4) (2) (1) (4) (4) (3) (4) (1) (3) (3)

185. 190. 195. 200. 205. 210. 215. 220. 225. 230. 235. 240. 245. 250. 255. 260. 265. 270.

(1) (4) (1) (4) (2) (2) (1) (1) (2) (1) (3) (1) (2) (4) (4) (4) (1) (1)

EXERCISE 3 : TEST YOURSELF 1. 1. 2. 3. 4. 5. 6. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 21.

(2) 2. (1) 3. (2) 4. (3) 5. (3) (3) The rest three are connective tissues. (2) Cock’s comb is also known as Wharton’s jelly. (2) Osteoclasts are bone eating cells. (3) Most of the sweat glands are eccrine type. (4) Endothelium and Muscular tissue are not connective tissues. (3) 7. (2) (4) Mesodermal epithelium can be pericardium or endothelium. (3) Chondrin is the protein of cartilage. (4) (1) Red pulp contains RBC which are absent in white pulp. (3) Tunica mucosa has three regions. The lamina propria is the middle one. (4) (1) Investing bone is also known as Dermal bone or Membranous bone. (3) This canal connects Haversian canals. . (3) The squeezing out of WBC is called Diapedesis. (1) (3) Brown fat provides 20- times more energy than white fat. (3) 20. (1) (2) γ-globulins (antibodies) are synthesized by Lymphocytes.

332 22. 23. 24. 25. 26. 29. 30. 31. 32. 33. 36. 37. 38. 39. 40. 41. 43. 44. 45. 46. 47. 48. 49. 50. 51. 52. 53.

BIOLOGY (3) Both epithelia are of simple squamous type. (1) This epithelium is present in urinary bladder and ureter. (4) The size of RBC is 7 - 8 µ and of platelets 3 - 5µ. . (3) Neurilemma is also present in non-myleinated fibres. (1) 27. (3) 28. (1) (4) In retina these neurons are present between sensory layer and ganglionic layer. (3) The fibrinogen is present in plasma and lymph but is absent in serum (2) (3) The increase in number of RBC is called polycythemia. (4) 34. (2) 35. (2) (1) (4) Heparin is sulphated polysaccharide. (2) WBCs show diapedesis. (1) Lymphocytes are 20-40% of WBCs. Neutrophils (not in options) are 50- 70%. (2) Acidophils or Eosinophils produce antitoxins against allergens. (1) 42. (2) (3) Marcello Malpighii is known to be the founder of Histology. (2) Though collagen fibres are stronger but less resistant to chemicals. (3) (2) (1) The cells of epithelial tissue are compactly arranged. (1) Accelerin (Factor VI) is actually formed from Proaccelerin (Factor V). (2) (3) Meissner’s plexus is a fine net work of parasympathetic fibres, in the submucosa of intestine. (4) Such areas have maximum wear and tear. (2) Haversian system is present in the bones of mammals only. (2) Sesamoid bone is formed by the ossification of ligaments or tendons.

54. 55. 56. 57. 58. 59. 60. 61. 62. 63. 64. 66. 67. 68. 69. 70. 71. 72. 73. 74. 75. 76. 77. 80. 83. 85. 87. 90. 92.

(4) All glands are epithelial in origin.\ (4) In RBCs, the TCA cycle is absent because of the absence of mitochondria. (2) (4) It is called polycythemia. . (1) In this disorder Glutamic acid in β- chain is replaced by Valine. (3) Each sub-unit contains one haem and one polypeptide chain. (2) Both structures have simple squamous epithelium. (3) They are the groups of ribosomes, and extend into dendrites also. (3) (4) Rest three elements are WBCs. (4) 65. (3) (2) The lymphocytes are also present in lymph. (2) Blood is a fluid connective tissue. (2) Accessory glands open into genital papillae. (4) DBV is distributive in first 13 segments and collective after 13 segments. (2) (1) Haemoglobin is dissolved in plasma. (2) (3) ‘Forest of nephridia’ is the term used for such nephridia in clitellum. (3) Both, anterior loops and testes are present in segment numbers 10th and 11th. (4) Typhlosole starts from segment number 27th. (3) Fertilisation occurs when sperms are released from spermetheca into cocoon. (2) Dorsal pores start from 12th segment. (1) Monocystis is the parasite of seminal vesicle. (2) Ecdysone is also known as moulting hormone. (2) Haemocoel is a blood filled cavity, and not a coelom. (3) Proventriculus is also known as Gizzard. (1) Rhabdome receives the image and is the part of receptor region of ommatidium. (1) Spiracles open into ‘atrium’ before forming tracheal tubes and tracheoles.

Chapter

8

Cell : The Unit of Life At a Glance

While going through the chapter pay special attention to the following – Terms – (i) Nucleoid (ii) Mesosome (iii) Heterophagosome (iv) Telolysosome (v) Subunit of parson (vi) Plastidome (vii) Plasmodesmata (viii) Nucleosome (ix) Diplosome (x) Polytene chromosome (xi) Lampbrush chromosome (xii) Chromatophores Differences – (1) Cytology and cell biology (2) Nucleus and nucleoid (3) Gram positive and Gram negative bacteria (4) Centrosome and centriole

All living organisms are constituted of structural and functional units called cell.

 



Cell Theory Prokaryotic cell  Cell wall and its modi�ication  Ribosomes and Inclusion Bodies  Genetic material Eukaryotic cell  Cell wall  Cell membrane  Endoplasmic reticulum  Golgi apparatus  Lysosomes  Ribosomes  Vacuoles  Nucleus  Plastids  Mitochondria  Cytokelton



Cytology is the study of form and structure of cells as well as their organelles with the Connecting Concepts help of microscope. These days cytology has been replaced by cell biology.  Microscopes are the instruments Cell biology is the branch of biology that deals with the study of structure, biochemistry, meant for viewing small things due to their magnification and resolving physiology, reproduction, evolution and genetics of cells. A number of biochemical powers. Resolving power is the ability to distinguish two closely placed objects techniques are used in the study of cell biology.



Robert Hooke in 1665 coined the term ‘cell’ and saw dead cell of cork.



Some organisms are composed of a single cell known as unicellular organisms while others, like us, composed of many cells, are called multicellular organisms.



All life begins as a single cell.



Cells are grouped into tissue, tissues into organ and organs into organ system, resulting in the division of labour.



All cells interact and cooperate with each other and remain partly dependent on each other.



Anton von Leeuwenhoek first saw and described a live cell.



Robert Brown later had discovered the nucleus.



Every cell has its own life span. The old & worn out cells are continuously replaced by new cells.



CELL THEORY 

Cell theory was proposed by Schleiden and Schwann in 1855 to explain the concept of the cellular nature of living organism.



But they did not explain as how new cells are formed. Rudolf Virchow in 1858 made a generalization “omnis cellula e cellula” i.e., all cells comes from pre-existing cells.

as distinct. Resolving power of naked eye is 100 µm, compound microscope is 0.25 – 0.3 µm, and electron microscope is 2Å.  Compound or Light Microscope : It consists of a reflector, objective lens, and eye lens. Its resolving power depends upon wavelength of light and numerical aperture of objective lens Numerical aperture is multiple of refractive index of medium (n) and sine of angle subtended by optical axis and outer ray covered by objective (sin θ). Magnification is multiplication of magnifying power of objective lens and eye piece.  Electron Microscope : It is a large sized instrument with an internal vacuum, high voltage (50,000 - 100,000 volts), a beam of electrons, a cathode filament of tungsten, electromagnets for focussing magnification and projection, and fluorescent screen or photographic plate for observation. Electron microscope has a very high resolving power and magnification. Detailed structures of larger cell organelles could be known only with the help of electron microscope.

334

BIOLOGY The three fundamental facts of the cell theory are as follows:

Check Point



All living organisms (animals, plants and microbes) are made up of cells and cell products i.e., cell is the structural unit of life.



All metabolic reactions in unicellular and multicellular organisms take place in cell i.e., cell is the functional unit of life.



Cells originate only from pre-existing cells, i.e., no cell can originate spontaneously or de novo

Exceptions to cell theory : i.

Fill in the blanks 1. In prokaryotic cells, ______ chromosome present in the center of cell in a region called ______ . 2. ______ and ______ are membrane less organelles. 3. ______ is the smallest cell 4. Active cells have surface volume ratio. 5. WBC, perform ______.

Viruses are acellular and do not have a cellular components. But posses genetic material and show multiplication.

ii. In some organisms, the body is not differentiated into cells through it may have numerous nuclei (coenocytes, e.g., Rhizopus). iii. Protozoans and some thallophytes have a uninucleate body (e.g., Acetabularia) which cannot be divided into cells. They are acellular. iv. Bacteria and cyanobacteria do not have nucleus and membrane bound organelles. v. RBCs and sieve tube cells are the cells without nucleus. vi. Protoplasm is replaced by nonliving materials in the surface cells of skin and cork. 

Significance of cell theory : Cell theory is one of the fundamental generalisation of biology.

AN OVERVIEW OF CELL A typical cell possesses three major elements — outer envelope, genetic material and cytoplasm. 

Outer Envelope: A cell is surrounded by an outer membrane called plasma membrane or plasmalemma. It isolates the cell interior. A distinct cell wall lies on its outerside in plant cells. Cell wall provides protection, rigidity and shape to cells.



Genetic Material: It represents hereditary material that not only controls the functioning of the cell but also contains information for forming the whole organism. Genetic material is DNA. In eukaryotes it is enclosed inside the nucleus as chromatin material. The latter appears as chromosomes during cell division. In prokaryotes, the genetic material lies freely inside the cytoplasm as coiled structure called nucleoid.



Cytoplasm: It is semifluid matrix that occupies the interior of cell between nuclear region and outer envelope. Cytoplasm is the area of major cellular or life activities which keep the cell in living state. Certain functions are associated with special cytoplasmic structures called organelles. Organelles are of three types (i) Membraneless, e.g., ribosomes, centrioles, (ii) Single Membraneous, e.g., endoplasmic reticulum, Golgi complex, lysosomes, microbodies, sphaerosomes. (iii) Double Membraneous, e.g., mitochondria, plastids (in plant cells).

Size & Shape 

Cells differ greatly in size, shape and activities. For example, Mycoplasma, the smallest cell, are only 0.3µm in length while bacteria could be 3 to 5µm. The largest isolated single cell is the egg of an ostrich, Acetabularia, a unicellular green alga is about 10 cm in length.



Cell of alga Caulerpa may be upto one metre. Among multicellular organisms, human red blood cells are about 7.0 µm in diameter, nerve fibres are the longest, upto 90 cm to few metres.

CELL : THE UNIT OF LIFE 

The upper limit or cell size or cell volume is determined by number of factors like : (i) Metabolic Activity : Metabolically active cells are small in size while less active ones are large, e.g., sperm (active) and egg (passive). (ii) Nucleocytoplasmic Ratio: Nucleus controls the metabolic activities of the cytoplasm. A higher nucleocytoplasmic ratio provides more efficient metabolic working. (iii) Surface Volume Ratio : Active cells possess a higher surface : volume ratio. This occurs in small cells, elongated cells and cells with surface invaginations or ingrowths like microvilli of absorptive cells.



Cells also vary greatly in their shape.



They may be disc-like, polygonal, columnar, cuboid, thread like, or even irregular.



The shape of the cell may vary with the function they perform. e.g., RBCs are biconcave to pass through capillaries and carry O2; WBCs are irregular to perform phagocytosis, nerve cells are long to conduct impulses, sperms have tail for motility etc.

Types of cells 

There are two basic types of cells i.e., prokaryotic cells and eukaryotic cells. They are differentiated on the basis of organisation of biomembranes, variety of cytoplasmic organelle and complexity of nuclear material.

PROKARYOTIC CELLS 

Prokaryotic cells are morphologically most primitive cells.



A single membrane surrounds the cell. It is without membrane bound nucleus.



Prokaryotic cells are devoid of membrane bound organelles like plastids, mitochondria and advanced (9 + 2) flagella.



They reproduce asexually by transverse binary fission or budding.



Prokaryotic cells are represented by bacteria, cyanobacteria (blue green algae), Mycoplasma and PPLO (pleuro-pneumonia like organisms).



Bacteria are unicellular organisms with prokaryotic cellular organisation. They were first discovered by Anton van Leeuwenhoek (1676) in pond water and tartar of teeth. The bacteria are the simplist living organisms reproduce by fission and are mostly pathogenic on human beings.



Bacteria are found in almost all places like hot springs, beneath the icebergs, in the intestine of man, deep in the soil, in sea water etc.

Size and Shape 

Prokaryotic cells vary greatly in their size from 1 to 10 µm in diameter. The smallest bacterium is Dialister pneumosintes (0.15 to 0.3 µm in diameter) and the largest bacterium is Spirillum volutans (500 µm).



Bacteria greatly vary in their shape also. The four basic shapes of bacteria are coccus (spherical forms) bacillus (rod-shaped), vibrio (comma-shaped) and spirillum (spiralshaped). Some bacteria assume different forms in their life cycle. They are said to be pleomorphic The prokaryotic cells have following important features:

Cell envelope & Its Modifications 

There are two types of bacteria i.e., gram positive and gram negative. A stain called Gram stain (a stain developed by C. Gram in 1884) is used to distinguish these two major bacterial classes.



Gram-positive bacteria: These bacteria are stainable by the Gram stain (e.g., Diplococcus pneumoniae, etc.). The cell wall of Gram-positive bacteria contains polysaccharides and mucopeptides. They extensively linked to one another to provide considerable strength to the wall e.g., Pneumococcus, Streptococcus, Bacillus, Clostridium, Mycobacterium, Streptomyces. Gram-negative bacteria: These are not stained by Gram stain (e.g., Escherichia coli, etc.).



335

336

BIOLOGY The cell walls of Gram-negative bacteria contain a similar network but have in addition an outer layer of lipids, complex with protein and polysaccharides. The wall of gram-negative bacteria is more complex e.g., Salmonella, Pseudomonas, Escherichia, Haemophilus, Helicobacter, Vibrio, Rhizobium. In both gram positive and gram negative bacteria the murein (constituent of cell wall) can be dissolved by lysozyme.

Connecting Concepts  Schizomycetes: Bacteria were previously called schizomycetes or fission fungi.

 Bacteriology: The science associated  with study of various aspects of bacteria is called bacteriology. Outer

Coverings

 Father of Bacteriology: Robert Koch Bacterial cell is covered by an (A) outer slime layer or capsule, (B) a middle cell wall and (1843 - 1910).  Presence or absence of capsule is (C) an inner cell membrane. genetically fixed. The Slime Layer or Capsule  Capsulated bacteria form smooth  colonies. They are known as S-type bacteria which are highly virulent.

 Non-capsulated bacteria form rough colonies and known as R-type bacteria.

Outside to the cell wall of most bacteria occurs a viscous gelatinous loose sheath called slime. When components of this layer are compactly arranged, it is called capsule. • Capsule serves as additional protective layer to the bacterial cell. • Capsulated bacteria are usually non-flagellated.

Cell Wall 

The plasma membrane is covered by a strong, rigid cell wall.



Apart from protection, it prevents the cell from getting ruptured due to very high osmotic and turgor pressure inside.



Cell wall is made of polysaccharides, proteins and lipids.



In the cell wall of bacteria there are 2 important sugar derivatives which are not found anywhere in biological world, i.e., NAG and NAM (N-acetyl glucosamine and N-acetyl muramic acid).

Plasma Membrane Connecting Concepts



 Cell walls of Gram-ve is thin, hard, less homogeneous, more complex multi  layered. It contain 10% peptidoglycan and is not destroyed by Penicillin. Cell wall of Gram +ve bacteria is thick, more homogenous and single layered, lipids are almost absent but contain 60-90% peptidoglycan. These bacteria are destroyed by Penicillin.

The plasma membrane is semi-permeable in nature and interacts with the outside world. This membrane is structurally similar to that of the eukaryotes.

 Outer layer of Gram-ve bacteria is made of lipopolysaccharides and Gram +ve bacteria is teichoic acid.  Gas Vacuoles : They are also called pseudovacuoles or air vacuoles. Gas vacuoles occur in prokaryotes. A gas vacuole is not a single structure but is a group of large number of submicroscopic polygonal gas vesicles. Each gas Fig. 8.1 A prokaryote cell of bacteria vesicle is surrounded by an extra-thin protein membrane. Gas vacuoles store Ribosomes & Inclusion Bodies metabolic gases, provide mechanical The cytoplasm of bacterial cells lack most of the membrane-delimited cellular organelles of strength, regulate buoyancy and dilute  the intensity of harmful radiations. eukaryotic cells, such as endoplasmic reticulum, Golgi complex, mitochondria, lysosomes,

centrioles, etc. Prokaryotic cells contain following structures :



Ribosomes : Bacterial ribosomes are slightly smaller than the ribosomes of eukaryotes (70S) It occurs freely in the cytoplasm.

CELL : THE UNIT OF LIFE •

337

Prokaryotic ribosomes are made of two subunits - 50S and 30S units which when present together form 70S prokaryotic ribosomes.

•

Several ribosomes may attach to a single m-RNA and form a chain called polyribosomes or polysome. Mesosomes • In some bacteria (e.g., Bacillus subtilis) the plasma membrane form certain invaginations or in foldings called mesosomes in the cytoplasm. •

The mesosomes have various functions, viz., respiratory, secretory etc.

•

Mesosomes play role in separation of two daughter nucleoids and in the formation of a new cell plate during cell division.

•

In some prokaryotes like cyanobacteria, there are other membranous extensions in the cytoplasm called chromatophores. It contains pigments known as bacteriochlorophyll that differ somewhat from the comparable pigments of eukaryotes.

Vacuoles : There are no true, fluid-filled vacuoles.

Connecting Concepts Inclusion bodies : Reserve materials in prokaryotic cells are stored in the form of inclusion  Depending upon the mode of respiration and their capability to bodies.

perform alternate mode of respiration,

These are not bounded by any membrane and lie free in the cytoplasm, e.g., phosphate bacteria are of six types : granules, cyanophycean granules and glycogen granules. Genetic Material •

In bacteria, a true nucleus with nuclear envelope, nucleolus and histone protein is absent. It is represented by a single-naked, double stranded, circular, ring like highly folded supercoiled DNA with no free ends. Such a nucleus without nuclear envelope is called nucleoid. Nucleoid is also called as nuclear body, prochromosome, chromatin body, prokaryotic chromosome, genophore, incipient nucleus, or bacterial chromosome.

1. Obligate Aerobes : The bacteria can perform only aerobic respiration. They are killed under anaerobic conditions, e.g., Bacillus subtilis. 2. Obligate Anaerobes : The bacteria can perform only anaerobic respiration. They cannot tolerate aerobic conditions, e.g., Clostridium acetobutylicum.

3. Facultative Anaerobes : These bacteria are normally aerobes which can switch over to anaerobic mode of respiration when oxygen is not available, e.g., Clostridium tetani.

•

Prokaryotic cells are haploid. They have much less amount of DNA.

•

Many prokaryotes have extra chromosomal, circular DNA molecules called plasmids.

•

The plasmid DNA confers certain unique phenotypic characters to such bacteria like fertility factor, nif genes, resistance factors and colicinogenic factors. Plasmids 4. Facultative Aerobes : The bacteria which can get associated temporarily with nucleoid are known as episomes. are normally anaerobes but can perform Plasmid DNA is used as vector in genetic engineering. aerobic respiration in the presence of

•

oxygen, e.g., purple non sulphur bacteria like Rhodobacter.



Respiration may be aerobic or anaerobic.



Nutrition may be autotrophic or heterotrophic.



Locomotion occurs by flagella that protrude from an intracellular “basal granule” through bacteria continue to perform anaerobic the plasma membrane and cell-wall. respiration or fermentation even in the Bacterial flagellum is composed of three parts - filament, hook and basal body. The presence of oxygen. They are called filament is the longest portion and extends from the surface projecting outside. aerotolerant anaerobes.

 

Many gram-negative bacteria bear many short, tubular and non motile structures on their cell wall. They are termed pilli and fimbriae depending on the length. It does not play a role in motility. The pilli are elongated tubular structures made of a special protein. The fimbriae are small bristle like fibres sprasting out of the cell.



If pilli participate in conjugation of bacteria, it is termed sex-pilli. In a few pathogenic strains of bacteria pilli are responsible for recognizing and attaching to the host and to rocks in streams.



Mitotic apparatus is not formed during cell division.



Both transcription and translation occur in the cytoplasm. mRNA does not require processing.

EUKARYOTIC CELLS

5. Aerotolerant Anaerobes : Lactic acid

6. Anaerotolerant Aerobes : The aerobic bacteria continue to respire aerobically even in the absence of free oxygen by using oxygen of oxidised salts like nitrate, e.g., denitrifying bacteria.

338

BIOLOGY 

Eukaryotic cells are characterized by extensive compartmentalisation of cytoplasm the presence of membrane bound organelles. The eukaryotic cells occur in all protists, fungi, plants and animals. Eukaryotic cells are typically composed of plasma membrane, cytoplasm and its organelles, viz., mitochondria, endoplasmic reticulum, Golgi complex, etc., and a true nucleus.



All eukaryotic cells are not identical. Plant and animal cell are different as the former possess cell wall, plastids and a large central vacuole which are absent in animal cells. On the other hand, animal cells have centrioles which are absent in almost all plant cells.

Fig. 8.2 Eukaryotic cell

Cell Components A eukaryotic cell consists of the following components: (A) Cell wall and plasma membrane, (B) Cytoplasm and, (C) Nucleus.

Cell Wall

 

The cell wall is a non-living, semi-rigid, external protective covering of the cell. Plant cells are characterized by the presence of a cell wall. Cell wall is entirely lacking in animals. It is made up of cellulose secreted by the cell itself. Primary and secondary cell walls are mainly composed of cellulose polysaccharide.



Lignin and suberin may be present in secondary cell wall.

 



The cell wall mainly consists of two parts i.e., •



microfibrils (consisting of cellulose and rarely of chitin) and

• ground substance or matrix. The cell wall is differentiated into 3 layers, viz, the middle lamella, the primary wall and the secondary wall.



Middle lamella : It is outermost layer of plant cell wall and act as cement between adjacent cells. It is chiefly composed of calcium pectate. In woody tissues it is highly lignified.



Primary wall : It is thin, single layered and first formed wall that is present on both sides of middle lamella. Primary wall is capable of growth and extension. It is composed of pectic substances, hemicellulose (glucose, xylulose, mannose, glucuronic acid), lipid and a loose network of cellulose microfibrils.



Secondary wall : It is very thick, rigid and loose the capacity of growth. It is formed in mature cells. It consists of three layers termed as S1, S2, S3. S2 is thickest and S3 is thinnest

CELL : THE UNIT OF LIFE

339

layer. Secondary wall is made up of hemicellulose and cellulose mainly. The cellulose Connecting Concepts microfibrils of the secondary wall are embedded in the matrix composed of hemicellulose,  The cell wall varies in thickness from lignin, pectin etc. 0.1µm to 10 µm in different cell.  Generally in most of the cases, cell wall is present from the very beginning but in slime fungi (myxomycetes) cell Plasmodesmata are cytoplasmic bridges between two adjacent cells which connects the wall is present for a very short time.

Plasmodesmata 

neighbouring cells.

 In fungi, cell wall is made up of chitin



Plasmodesmata are characteristic of multicellular plants that enables the solutes to (polymer of N-aetyl glucosamine). move considerable distances through the pits without crossing differentially permeable  Lomasomes : They are vesicular and membranes. membranous structures usually present



Plasmodesmata produces a living system called symplast.

Functions of Cell Wall 

The cell wall provides mechanical strength.



It acts as a barrier against entry of viral, bacterial and fungal pathogens.



It helps in transport of materials and metabolites in and out of the cell.



between cell wall and plasmalemma of plant cells. Their definite function is not known but probably they help in cell wall elaboration. They are mainly found in fungi.

 In fleshy fruits during ripening the pectic substances of the middle It withstand the turgor pressure which develops within a cell due to high osmotic lamella are dissolved by the proteolytic enzymes. The cells are, therefore, pressure. lossened and fruit becomes soft.

Cell Membrane 

 Tertiary wall are present in tracheids of gymnosperms. It is a purely cellulosic The term cell membrane was coined by Nageli and Crammer in 1855. In 1931 C.B. Plowe in nature.

had given the term plasma membrane or plasmalemma.  

 Deposition of Cell wall :

The cell membrane is a living, thin, elastic and semipermeable, membranous covering 1. Lignin : It is a polysaccharide of plant and animal cells. It is also called as biological membrane or biomembrane. which deposits mostly in xylem cells Plasmalemma occurs in both prokaryotes and eukaryotes. Intracellular biomembranes are and makes them hard and lignified. found in eukaryotic cells around most cell organelles as well as inside some cell organelles Due to deposition xylem tracheids (e.g., thylakoids in chloroplasts). take up different forms, e.g., annular

thickening, spiral thickening, scalariform thickening.



Endoplasmic reticulum is also lined by membranes.



Some membranes have specific names, e.g., tonoplast around vacuole, nuclear envelope 2. Suberin : It is a derivative of fatty around nucleus.



Double membrane covering is present around nucleus, mitochondria and plastids.

acids deposited on cork cells. Suberin is impermeable to water.



Cell membrane is composed of lipids that are arranged in a bilayer.

3. Cutin : It is a wax-like fatty substance.



Also, the lipids are arranged with the polar head towards the outer sides and the hydrophobic It is deposited on the epidermal cells in the form of cuticle which reduces tails towards the inner side.



This ensures nonpolar tail of saturated hydrocarbons protected from the aqueous environment. xerophytes, thin in mesophytes and The lipid component of the membrane mainly consists of phosphoglycerides. absent in hydrophytes.

 

loss of water. Cuticle is very thick in

Later, biochemical investigation clearly revealed that the cell membranes also possess 4. Silica : In some plants silica particles protein and carbohydrate. are deposited in cell wall which give a rough touch, e.g., Equisetum and The ratio of protein and lipid varies considerably in different cell types.



In human beings, the membrane of the erythrocyte has approximately 52 per cent protein Saccharum munja. 5. Mucilage : Some cells are slippery and 40 per cent lipids.



It is about 75 – 100Å thick.

Chemical organization of membrane Unit membrane model of plasma membrane  

6. Crystal of calcium oxalate and calcium carbonate are deposited in cell Unit membrane model was proposed by Robertson in 1959. wall in members of cucurbitaceae and According to this model, all biomembranes from prokaryotes to eukaryotes have similar moraceae.

structure. 

to touch due to secretion of mucilage, e.g., blue-green algae. The cells can withstand extremes of temperature, i.e., very low or very high.

The unit membrane is 75 Å thick and it consists of a bimolecular lipid leaflet sandwiched

340

BIOLOGY between outer and inner layers of protein organized in the β-pleated sheet configuration (protein-phospholipid – phospholipids- protein). 

Drawback of unit membrane model - This model does not explain the permeability and elasticity of plasma membrane.

Fluid mosaic model of plasma membrane Check Point 1. Name the following organelle. (i) Ribosomal factory (ii) Power house of the cell (iii) Scavanger of cell (iv) Kitchen of the cell

Connecting Concepts



S.J.Singer and G. Nicolson in 1972 proposed the most accepted model of membrane structure only after the advent of electron microscope in 1950.



According to this model the lipid bilayer is a semifluid in which the proteins are dispersed to give mosaic appearance to the whole membrane.



The concept of fluidity in this model implies that components of membrane i.e., lipids, proteins and oligosaccharides are held in their positions by means of non-covalent interactions.



Fluidity of plasma membrane is due to phospholipids which is rich in unsaturated fatty acids. Phospholipids form the main component of cell membrane because it provides structural framework to the membrane.



Lipids are amphipathic, i.e., they are structurally asymmetric with polar hydrophilic and non-polar hydrophobic groups. On the outer side of some of the lipids sugar chains are attached to their polar heads and hence are known as glycolipids.



Two kinds of proteins are found in the membrane the peripheral or extrinsic protein and the integral or intrinsic proteins.

 In lipid part, plasma membrane also contains cholesterol. Cholesterol molecules are more rigid than the phospholipids and therefore presence of cholesterol confers stability of eukaryotic membranes. Prokaryotic membranes lack cholesterol.  However, in some bacteria pentacyclic sterol like molecules called as hopanoids are present. Hopanoids stabilize the bacterial membrane.

•

Peripheral or extrinsic proteins : The peripheral proteins are completely external and are loosely attached to the polar heads of the lipid on both the surfaces. Extrinsic proteins can freely move in plasma membrane. They function as carrier for transport of material. They constitute 20- 30% of total proteins.

•

Integral or intrinsic proteins : These proteins are tightly held to phospholipids. Small integral proteins partially project from either surface of the membrane while the larger ones embedded in the entire thickness of the membrane and project from one or both the surfaces of the plasma membrane. Intrinsic proteins form channels which provide a rapid passage to water soluble materials across the plasma membrane. They constitute 70% of total proteins.

Check Point State True or False. 1. Acetabularia is unicellular organism. 2. Golgi complex is double membrane organelle. 3. Flagella in prokaryotic has (9+0) arrangement while those in eukaryotes has (9+2) arrangement.. 4. RBCs and sieve tube cells cells are without nucleus. 5. Unicellular prokaryotic cells are more advanced.

Fig. 8.3 Fluid-mosaic model of cell membrane

Functions 

One of the most important function of plasma membrane is the transport of the molecules across it. The membrane is selectively permeable to some molecules present on either side of it. Many molecules can move freely across the membrane without any requirement of energy. This is called as passive transport.

CELL : THE UNIT OF LIFE

341



Neutral molecules move by simple diffusion along the concentration gradient i.e., from higher concentration to lower concentration. Movement of water by diffusion is called osmosis.



As the polar molecules cannot pass through the nonpolar lipid bilayer, they require carrier protein of the membrane to facilitate their transport across the membrane.



A few ions or molecules are transported across the membrane against their concentration gradient, i.e., from lower to higher concentration. Such type of transport is called as active transport because it is energy dependent process in which ATP is utilised, e.g., Na+/K+ pump.

Protoplasm 

Protoplasm is present in all living cells and performs all vital functions of a cell, hence, J. Huxley defined it as ‘Physical basis of life’. Dujardin (1835) discovered it and named it as ‘Sarcode’. Purkinje (1837) renamed it as ‘Protoplasm’.



Protoplasm is a complex, granular, elastic, viscous and colourless substance. •

Protoplasm is considered to be a “polyphasic colloidal system”.

•

The main consituent of protoplasm is water. Various soluble substanes such as glucose, minerals, etc., remain dissolved in water and form a true solution.

•

In this solution various larger insoluble organic compounds such as fatty acids, proteins and some carbohydrates are suspended in the form of colloidal particles.

•

The true solution acts as a dispersion medium whereas different colloidal particles such as proteins and lipids, etc., constitue dispersed phase.

•

Some emulsions or suspensoids are also present and hence protoplasm is a complex colioidal system of many phases.

•

The colloidal particles present in protoplasm such as enzymes provide a large surface area for various chemical reactions to occur and also have a characteristic property of adsoption. The large protein molecules are hydrophilic in nature and adsorb water molecules.

•

Protoplasm show sol gel interconverssion.

•

Some of the proteinaceous constituents of the protoplasm coagulate at high temperature (app. at 60ºC or above) which results in the death of the cells.

•

The exact chemical composition of protoplasm cannot be analyse as it undergoes continuous changes and its composition is not, therefore, constant.

•

The approximate constitution of plant protoplasm is as follows : Water

–

about 90%

Proteins

–

7.2%

Carbohydrates –

2.0%

Fats

–

1.0%

Minerals

–

DNA and RNA – •

1.0% in traces

Maximum water content in protoplasm is found in hydrophytes, i.e., 95%, whereas minimum in seeds, spores (dormant organs), i.e., 10–15%. In animals water is less (about 65%) and proteins are more (about 15%).



Inorganic matter is found in ionic state. Main cations are calcium, potassium, magnesium and iron. The main anions are nitrates, sulphates, bicarbonates and chlorides. These mineral elements specifically influence the vital activities of the cell and play an important role in the osmosis between the cell and its environment.



Among the organic substances, glucose, fructose and sucrose are the main carbohydrates found in the protoplasm. They provide energy for many cellular activities. Lipids are also found in the protoplasm to liberate energy and integral part of membranes.

342

BIOLOGY 

Proteins (64% of total solid substances) form the most significant part of protoplasm.



Most of the chemical reactions in protoplasm are carried out by the help of enzymes which are proteins.



Different types of pigments, latex, vitamins, growth regulators, enzymes and alkaloids are also found in protoplasm and play specific roles in the cell.



pH varies in different cells. Even in one cell it varies from time to time. (from 5.2-8.5) but pH of a normal cell can be considered as 7.

Endomembrane System Connecting Concepts



 GERL. – A complex of Golgi appartus, endoplasmic reticulum and lysosome.

Each membranous organelle is distinct in terms of its structure and function. Many of these are considered together as an endomembrane system because their functions are coordinated. Endomembrane system includes endoplasmic reticulum, Golgi complex, lysosomes and vacuoles.

The Endoplasmic Reticulum (ER) 

Garnier (1897) firstly observed and named them as ergastoplasm. Porter and Kallman (1952) coined the term endoplasmic reticulum.



Endoplasmic reticulum is also called as ‘endoskeleton of the cell’ or ‘endomembranous system of the cell’. ER is diffused cell organelle in the cytoplasm of all eukaryotic cells.



The endoplasmic reticulum is bounded by a single unit membrane. The membrane of endoplasmic reticulum is supposed to be originated by pushing of plasma membrane in the matrix. The membrane of endoplasmic reticulum is found to be continuous with the nuclear membrane and plasma membrane.



Endoplasmic reticulum is vast reticulum or network of inter-connected tubules and vesicles. Hence, ER divides the intracellular space into two distinct compartments i.e. luminal (inside ER) and extra luminal (cytoplasm) compartments.

•

ER consists of three shapes i.e., cisternae, tubules and vesicles.

Fig. 8.4 Endoplasmic reticulum

CELL : THE UNIT OF LIFE

343 Check Point Fill in the blanks with suitable word/ words 1. The longest cell of human body is ______. 2. Movement of ______ across the selective permeable membrane is osmosis. 3. Chromatophores containing ______ found in ______. 4.

Fig. 8.5 Endoplasmic reticulum : Cisternae, vesicles and tubules



•

Cisternae – These are long, flattened and unbranched units arranged in stacks. It is 40-50 nm thick.

•

Tubules – These are long, isolated and branched units of 50-200 nm thickness.

•

Vesicles – They are 25-500 nm in diameter.

Structure of ER and Golgi body is similar but in ER cisternae, tubules and vesicles are isolated in cytoplasm and do not form complex as in Golgi body.

Types of ER There are two types of endoplasmic reticulum i.e., 

Smooth or agranular ER : They do not have attached ribosomes on their surface. The SER is well developed in those cells which are actively concerned with the synthesis and secretion of steroid hormone. It is also concerned with the synthesis of lipid etc. The SER is present in glycogen storing cells of the liver, intestinal cells, adipose cells, spermatocytes, leucocytes and muscle cells. The ER of the muscle cells is called sarcoplasmic reticulum.



Rough or granular ER : They bear ribosomes on their surface. The cells which are active in protein synthesis have RER in abundance. Ribosomes attached to the ER membrane by their larger sub-units.

Functions 

Mechanical support : The endoplasmic reticulum forms the framework of the cytoplasmic matrix and it provides mechanical support to it.



Intracellular exchange : It also acts as an intracellular circulatory system and it circulates various substances into and out of the cells by the membrane flow mechanism.



Lipid secretion : Lipid is synthesized by SER, stored into Golgi complex before finally being incorporated into cytoplasm as lipid droplet and extruded outside of cell. The major lipids synthesized by SER are phospholipids and cholesterol.



Detoxification : SER is concerned with detoxification of drugs and steroids.



Formation of nuclear membrane : Fragmented vesicles of disintegrated nuclear membrane and ER elements arrange around chromosomes to form a new nuclear membrane.

Golgi Apparatus 

Golgi apparatus or Golgi complex is a stack of flattened, membrane bound, parallely arranged organelles that occur in the association of endoplasmic reticulum in the cytoplasmic matrix.



Camillo Golgi (1898) first detected these structures as densely stained reticular structures near the nucleus.



The Golgi bodies of plants are called dictyosomes because of their apparent net like structure.



Each Golgi complex is composed of many lamellae, tubules, vesicles and cisternae of 0.5 µm to 1.0 µm in diameter. The membranes of Golgi complex are made of lipoproteins and these are supposed to be originated from the membranes of endoplasmic reticulum.

5.

______ can dissolve the bacterial cell wall. The thickness of biological membrane is ______.

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BIOLOGY Connecting Concepts



 Biogenesis : Nucleus is essential for maintenance and formation of Golgi apparatus. In all probability, new Golgi  apparatus develops from division of the pre-existing one. Other possibilities are by invagination of plasmalemma, evagination of nuclear envelope and from endoplasmic reticulum.  Maturing face of Golgi apparatus having acid phosphatase and specialised to produce lysosomes.  Around Golgi body, ground substance is present in which cell organelles (ribosomes) are absent, it is called ‘zone of exclusion’.

Various enzymes like transferase, adenosine diphosphatase, thiamine phosphatase, glucose6-phosphatase etc. are found in Golgi body of which thiamine phosphatase is marker enzyme of Golgi body. Golgi body is present in all cells of eukaryotes but absent in mature RBCs of mammals, sieve tubes, bryophytes etc. Golgi body consists of following parts; •

Cisternae or saccules : The cisternae are the most conspicuous part of Golgi body. These are plate like unbranched membranous structures slightly concave. The saccules lie in parallel array.

•

One Golgi body usually have 3 to 8 cisternae in a stack in animal cells and 10 to 20 cisternae in plant cells. Mono cisternal Golgi body is found in fungi.

•

Each cisternae has two faces – Convex or the forming face and concave or the maturing face. The concave and the convex faces of the organelles are entirely different, but interconnected.

•

Tubules : These are parallel fibrous intercisternal elements of a diameter of 70-80Å, that connect cisternae to each other.

•

Vesicles : These are spherical structure of a diameter of 600Å. They arise by budding from tubules and are filled with secretory material.

Fig. 8.6 Golgi complex

Functions 

The Golgi apparatus principally performs the function of packaging materials to be delivered either to the intra-cellular targets or secreted outside the cell.



Materials to be packaged in the form of vesicles from the ER fuse with the forming face of the Golgi apparatus and move towards the maturing face. This explains, why the Golgi apparatus remains in close association with the endoplasmic reticulum.



A number of proteins synthesised by ribosomes on the endoplasmic reticulum are modified in the cisternae of the Golgi apparatus before they are released from its maturing face.



Golgi apparatus is the site of formation of glycoproteins and glycolipids.



Golgi body has secretory function also.



In plant cells the Golgi complex is known as dictyosome. It secretes necessary materials for cell wall formation during cell division.



Vesicles of Golgi body secrete Ca++ and Mg++ pectates that forms middle lamella between two plant cells.



Golgi bodies form acrosome during spermiogenesis.



Formation of lysosome is collective function of Golgi body and ER.



Golgi body recycles and reprocess membrane fragments which reach the cytoplasm by endocytosis.

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Connecting Concepts

Fig. 8.7 Secretion of Golgi complex

Lysosomes

 Acid hydrolases are divided into 6 categories i.e., protease, galactosidase, phosphatase, nuclease, sulphatase, esterase.  Stabilizers are more active in healthy



Lysosomes were discovered by Christian de Duve (1955) in liver cells and called it cells. Destabilizers or labilizers e.g., ““pericanalicular dense bodies”. Novikoff called it lysosome. progesterone, testosterone, vitamins A,



Lysosomes are tiny spheroid or irregular-shaped, membrane bounded vesicles.



D, E, K, and UV radiations etc. are also present in lysosomal membrane. These Lysosomes are originated by Golgi complex and contain many hydrolytic enzymes increase the chances of autolysis.

(amylases, lipases, proteases, carbohydrases) optically active at the acidic pH.    

 Crinophagy : It is conversion of complex and inactive hormones into simple These enzymes are capable of digesting carbohydrates, proteins, lipids and nucleic and active ones through lysosomes. acids. In endocrine glands, lysosome digests Lysosomes are popularly called “suicide bags”. They are also called as lytic bags, scavenger the excessive secretory granules of hormones. Release of thyroxine of cell or disposal units. hormone from thyroglobulin stored They occur in all the animal cells except RBCs. in thyroid follicles is carried out by lysosomal protease.

Lysosome exhibits polymorphism since they are of 4-types. •

•

Primary lysosomes or storage granules or protolysosome : Vesicles of Golgi bodies contain enzymes are called primary lysosome. Lysosomes are filled with 40 different types of digestive enzymes. It stores acid hydrolases in inactive form that becomes active in acidic medium.

 Spherosomes or plant lysosomes :

These are lysosomes of plants that contain several hydrolytic enzymes. They are discovered by Dangeared. The term spherosomes was given by Parner. These are major site of lipid synthesis and storage in plant cell Lysosomal membrane contains stabilizers eg., cortisone, cholesterol, chloroquine (98%). Spherosomes arise directly from etc. These stabilizers stabilize the lysosomal membrane by preventing its rupture endoplasmic reticulum.

and preventing autolysis.

•

Secondary lysosomes or Heterophagosome : Secondary lysosomes are formed when primary lysosome fuses with phagosome. They are also known as digestive vacuoles.

•

Autophagic vacuoles or Cytolysosome : Primary lysosomes become autophagic when they start engulfing and digesting the cell organelles. They are formed in starvation condition.

•

Residual bodies or Telolysosomes : The secondary lysosomes as well as the autophagic vacuoles containing undigested matter are called residual bodies. These may be eliminated by exocytosis.

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BIOLOGY Functions They are primarily meant for digestion. It may be intracellular or extracellular digestion. Connecting Concepts



Cellular digestion : Digestion of whole cell through lysosomal enzymes. Some times all lysosomes of a cell burst to dissolve the cell completely. Old cells and unwanted organs of embryo are  removed by autolysis. Cathepsin of lysosome digests the tail of tadpole  during metamorphosis.

Intracellular digestion – It is of two types •

Heterophagy: They help in the digestion of food material which comes in the cell by pinocytosis and phagocytosis.

•

Autophagy: During starvation lysosomes engulf and digest old or worn out cell organelles.

Extracellular digestion – Lysosomes of osteoclasts (bone eating cells) dissolve unwanted parts of bones. Extracellular digestion by lysosomes also occur in fungi. Defence – They are abundant in leucocytes for defence against microbes etc.

Lysozyme : It is enzyme with antiseptic properties due to its action on bacterial cell walls. Besides lysosomes, it is present in saliva, tears, nasal mucus, gastric juice, milk, egg white and many tissues. Anthyocyanins : Pigments are responsible for the different colours of flowers, i.e., violet, purple, blue, red or brown. Anthocyanins also occur in coloured roots, e.g., beet root, in coloured stems, e.g., balsam stem and in some variegated leaves of Croton, Amaranthus. Anthocyanins act as a shield for chloroplast and protoplasm against strong sunlight. They also act as insect attractants during pollination. Anthocyanins are soluble in water and alcohol and extracted on boiling in water. These pigments change their colour with change in pH of cell sap, e.g., red in acidic medium and blue in alkaline.

Fig. 8.8 Formation of lysosomes and intracellular digestion in them.

Vacuoles The cytoplasm of many plants and some animal cells (i.e., ciliate protozoans) contains numerous small or large-sized, hollow, liquid-filled structures called vacuoles.  The solution of vacuoles is known as vacuolar sap. It contains many dissolved solutes such as organic acids, soluble carbohydrates, soluble nitrogenous compounds as nitrates, enzymes, tannins, chlorides, phosphates, amino acids, alkaloids and anthocyanin pigments.  In plant cells, the vacuoles can occupy up to 90 percent of the volume of the cell. The vacuole is bound by a single membrane called tonoplast.  In a young cell, vacuoles are absent or smaller vacuoles are present. As the cell enlarges, these smaller vacuoles fuse and form a large central vacuoles at maturity. So in a mature cell the protoplasm is present as a thin layer, pushed towards the wall of the cell. This thin layer of protoplasm is called as primordial utricle. Functions 



 

The main functions of vacuoles are storage, transmission of the materials and the maintenance of internal pressure of the cell. These vacuoles contain water, phenol, flavonoids, anthocyanins (blue and red pigment), alkaloids and storage products, such as sugars and proteins. In Amoeba the contractile vacuole is important for osmoregulation. In protista food vacuoles are formed by engulfing the food particles.

Ribosomes 

Ribosomes are amembraneous, smallest cell organelle and thus they can be seen only with electron microscope.



Ribosomes are first observed by Robinson and Brown in 1953.



Palade observed them in animal cells (1953) and named them ribosomes in 1955.

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347



Ribosomes are small, spherical structures. Either they are found attached with the Connecting Concepts membrane of endoplasmic reticulum to form granular or RER or found free floating in  Organelle ribosomes occur in the cytoplasm.



Except mammalian RBC all living cells have ribosomes.



Protein synthesis take place on both forms of ribosomes.

Types of Ribosomes There are two types of ribosomes viz., prokaryotic ribosome and eukaryotic ribosome:

two semi-autonomous organelles as mitoribosomes in the matrix of mitochondria and plastidoribosomes inside the matrix or stroma of plastids (e.g., leucoplasts, chloroplasts).  Centrifugation separation techniques are based upon the behaviour of particles in an applied centrifugal field. The particles are suspended in a specific liquid medium, held in tubes or bottles, which are placed in a rotor. The rotor is placed centrally on the drive shaft of a centrifuge. Particles which differ in density, shape or size can be separated since these sediment at different rates in the centrifugal field. The sedimentation rate of a particle is proportional to the centrifugal field applied.



Prokaryotic or 70S ribosomes : It is found in prokaryotes as well as in chloroplasts and mitochondria of higher organisms. It is called 70S because the sedimentation coefficient of the complete ribosome is 70S (smaller subunit is 30S and bigger subunit is 50S). Sedimentation coefficient is indirectly the measure of density and size.



Eukaryotic or 80S ribosomes : In eukaryotes, each ribosome is 80S, composed of a smaller subunit 40S and a larger subunit 60S. The ribosomes remain attached with the membranes of endoplasmic reticulum by the 60S subunits with the help of ribophorins. The 40S subunits occur on the larger unit and form a cap-like structure.



The two subunits come together only during protein synthesis. Normally they are separate. Union or separation of the two subunits is related to Mg++ concentration—united at concentration of 1—2 mM, form dimers above it and dissociate below it (0.5 mM in  Theodor Svedberg prokaryotes and 0.3 mM in eukaryotes). The subunits may break if Mg++ concentration the technique of is reduced further.

developed analytical ultracentrifugation for which he got the Nobel prize in 1926. He used this technique to estimate the mass of haemoglobin as 68,000 daltons. In his honour the unit of sedimentation coefficient is named as Svedberg unit (S) which is proportional to molecular weight of sedimenting particles  In ribosomes, 60% RNA is double stranded or helical.  Out of the total RNA contents of a cell, 70-75% is present in ribosomes.

 Special proteins called chaperons assist freshly synthesised polypeptides Ribosome is formed of RNA and protein. So these are also known as ribonucleoprotein in their proper folding. They also help in particle (RNP). transport of proteins into various cell In prokaryotes, ribosomes are synthesised in the cytoplasm while in eukaryotes it occurs organelles like mitochondria, nucleus in the nucleolus. and chloroplasts.

Fig. 8.9 Form of ribosomes and its subunits

 

Functions 

They are the sites of protein synthesis.



Cytoplasmic ribosomes synthesize structural proteins (peripheral or extrinsic proteins of plasma membrane), proteins found in microbodies, chloroplast and mitochondria and proteins of cytosol such as enzymes of glycolysis or proteins of cytoskeleton, i.e., cytoplasmic ribosomes synthesize proteins which are used inside the cell.



One the other hand, ‘ribosomes attached on ER’ synthesize proteins for transport (i.e., used outside the cell), integral or intrinsic proteins of membrane and proteins of organelles like Golgi complex, lysosomes and plant vacuoles.

Cytoskeleton 

An elaborate network of filamentous proteinaceous structures present in the cytoplasm is collectively referred as cytoskeleton.

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BIOLOGY

Connecting Concepts  Intermediate filaments are unbranched, made up of structural proteins, i.e., keratin, vimentin and desmin. Intermediate filaments are about 10 nm in thickness and are larger than microfilaments. These filaments help the nucleus in maintaining its position in the cell and often interconnect the nucleus envelope with the cell membrane.



Microtubule, microfilament and intermediate filaments along with ER form cytoskeleton.



The cytoskeleton in a cell are involved in many functions such as mechanical support, motility, maintenance of shape of the cell.

Microtubules 

Microtubules are discovered by De Roberties and Franchi in 1953.



These are hollow structures, consist of tubulin protein.



Each protein dimer is made up of α and β monomers. The diameter of microtubules is 25nm.



Microtubules are found in centrioles, cilia, flagella and spindle fibres. In plants, microtubules are often found associated with cell wall.

Functions

 Immotile cilia: Cilia and flagella may  not be able to vibrate due to (i) Absence of central fibrils. (ii) Deficiency of dynein arms. In human beings the immotile cilia  syndrome leads to chronic bronchitis, sinusitis and infertility. 

They form cytoskeleton that maintains the shape of the cell and also provide support to the cell. They help in transport of cell wall material from Golgi body to outside of cell. During cell division they become distinct and form spindle fibres. They form motile elements of cilia and flagella

Microfilaments 

Microfilaments are non-living, solid and consists of actin protein.



Microfilaments were discovered by Pelvitz in 1974.



These are absent in cell organelles.



The microfilaments are 4-6 nm in diameter. They occur next to plasma membrane where they form a web in ectoplasm.

Functions 

They help in streaming movement of cytoplasm or cyclosis.



They help in gliding amoeboid motion shown by Amoebae, leucocytes and macrophages.



They help in muscle contraction.

Cilia and flagella 

Cilia and flagella are contractile filamentous or hair-like outgrowths of the cytoplasm, which help in cell movement, excretion, secretion and transportation.



Cilia and flagella are similar in structure but cilia is smaller than flagella. They are found in eukaryotic cells (except slime mould) and prokaryotic cells.



Both structures of microtubular framework enclosed by an extension of the plasma membrane.



The ciliary apparatus of cilia and flagella consists of 2 parts viz., shaft, and basal body. •

Shaft : Shaft or cilium projects out of the cell surface. It consists of two parts i.e., an outer covering called sheath and basic framework core is called axoneme. Axoneme posses a number of microtubules running parallel to the long axis.

•

Basal granules or kinetosomes : Both cilium and flagellum emerge from centriolelike structure called the basal bodies. The cilia and flagella are chemically consist of tubulin and dynein proteins and adenosine triphosphate (ATP).

•

The axoneme usually has nine pairs of doublets of radially arranged peripheral microtubules and pair of centrally located microtubules. Such an arrangement of axonemal microtubules is referred to as the 9 + 2 array.

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Centrosomes and Centrioles

Check Point



Centrosome is an organelle usually containing two cylindrical structures called centrioles.



They are surrounded by amorphous pericentriolar materials. Both the centrioles in a centrosome lie perpendicular to each other in which each has an organisation like the cartwheel.



The centriole appears as two cylinders at right angle to each other during the anaphase and telophase. A pairs of centrioles form a diplosome that are located at one pole of interphasic cell outside the nuclear envelope of animal cells. The cytoplasm surrounding the centriole is called ‘centrosphere’ or ‘kinoplasm’. Centriole and centrosphere together are called as centrosome.



Centrioles duplicate before cell division so that dividing cell has a pair of centrioles at each pole.



They are made up of nine evenly spaced peripheral fibrils of tubulin. Each of the peripheral fibril is a triplet. The adjacent triplets are also linked. The central part of the centriole is also proteinaceous and called the hub, which is connected with tubules of the peripheral triplets by radial spokes made of protein.



The centrioles form the basal body of cilia or flagella and spindle fibres that give rise to spindle apparatus during cell division in animal cells.



It has (9 + 0) pattern.



Centriole is not covered by any membrane. Plasma membrane

1. Give the sepecific scientific terms for the following : (a) Cluster of ribosomes found in cytoplasm. (b) Extensive infoldings of inner membranes of mitochondria (c) Stacks of closely packed thylakoids (d) Stalked particles on the inner membrane of mitochondria.

Peripheral microtubules (doublets)

Central sheath

Interdoublet bridge

Radial spoke

Central microtubule

Fig. 8.10 Diagrammatic representation of internal structure of centriole

Microbodies 

Microbodies are single membrane bound, minute spherical structures that contain various enzymes.



These are present in both plant and animal cells.



Microbodies are of two types i.e., peroxisomes and glyoxysomes.

Peroxisomes     

Peroxisomes are the smallest membrane bound cell organelles having a diameter of 0.1 µ. Connecting Concepts It is discovered by Tolbert. These organelles were named peroxisomes because these are  Luciferase enzyme, generating light in fire flies, is also present in the sites of formation of hydrogen peroxide (H2O2). peroxisomes. H2O2 is a highly reactive and toxic oxidizing agent. Peroxisomes are found only in C3 plants as photorespiration take place in C3 plants. These are also reported in animal cells, i.e., liver and kidney cells. The peroxisome contains several enzymes such as amino transferase, glycolate oxidase, glyoxylate reductase, peroxidase and catalase, etc. (Catalase destroys H2O2 produced during the conversion of glycolate to glyoxylate). Catalase enzyme is present in high concentration in these organelles.

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BIOLOGY

Glyoxysomes  

Glyoxysomes were discovered by Beevers in 1961 from castor endosperm. These are small, spherical vesicles enclosed by a single unit membrane.



Glyoxysomes are generally found in cells of yeast, Neurospora and in germinating fatty seeds where fat is being converted into carbohydrates, i.e., glyoxylate cycle (gluconeogenesis).

Nucleus 

Nucleus is centrally located, spherical and largest component of all the eukaryotic cell.



Robert Brown (1831) for the first time described and termed the prominent body within the cell as nucleus.



Later the material of the nucleus stained by the basic dyes was given the name chromatin by Flemming.

Connecting Concepts

Except mature mammalian RBC and sieve cell of phloem, every living cell has nucleus.  Nucleus is the ‘controlling centre of  cell’ is proved by J. Hammerling (1934),  Coenocytes are formed by repeating karyokinesis in plants and syncytium condition by grafting experiments on two species is formed by fusion of cells in animal cells and multinucleate form in slime moulds are of unicellular green alga Acetabularia, called plasmodium. i.e., A. mediterrranea and A. crenulata. The body of alga is divided into three Structure of nucleus parts - rhizoid, stalk and cap.  Nucleus is present in rhizoid. The cap of Acetabularia crenulata has loose rays while that of Acetabularia mediterranea is umbrella- like. It was observed that if the stalk of one species is grafted on the rhizoid of another species, then the cap formed is similar to that species to which the rhizoid belongs. It proves that the shape of the cap is determined by the nucleus which is present in rhizoid.

A typical nucleus consists of four structures: (i) nuclear membrane, (ii) nucleoplasm (iii) chromatin and (iv) the nucleolus. 

Nuclear membrane or karyotheca : The nucleus is bounded by two unit membranes which are separated by a 100-500Å wide perinuclear space. The nuclear membranes are also known as karyotheca or nuclear envelope or nucleolemma.



The outer membrane usually remains continuous with the endoplasmic reticulum and also bears ribosomes on it.



At a number of places the nuclear envelope is interrupted by minute pores, which are formed by the fusion of its two membranes. These nuclear pores are the passages through which movement of RNA and protein molecules take place in both directions between the nucleus and the cytoplasm.

 Binucleate condition is present in Paramaecium.  Below the nuclear envelope, a filamentous network of protein called nuclear lamina is present. Its function is to attach chromosomes to nuclear envelope and to help in the growth of nuclear envelope.

Fig. 8.11 Nucleus

Nucleoplasm 

The fluid filled in nucleus is known as nucleoplasm or karyolymph.



The chemical composition of nucleoplasm is similar to cytoplasm but it contains high concentration of nucleotides in the form of DNA and RNAs. Nucleoplasm is the site of enzyme activities and the synthesis of DNA, RNA and ribosomal subunits takes place here. Nucleolus and chromatin material are present in nucleoplasm.



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351

Chromatin 

      



In interphasic nucleus, the genetic material (DNA) is seen as the thread like structure called chromatin or chromatin fibres. During cell divisions (mitosis and meiosis) chromatin fibres become condensed to form thick structures called chromosomes. E. Strasburger (1875) discoverd these distinct structures during cell division. Waldeyer (1888) gave the term chromosomes (Chroma-colour+soma-body) to them because they get stained with basic dyes like basic fuchsine and acetocarmine. In all eukaryotes, the nucleus contains definite number of chromosomes having definite size and shape. Electron microscopic studies show that chromatin fibres consist of a string of bead like repeating units called nucleosomes. The nucleosomes are similar in all eukaryotes. The size of chromosome can be measured at metaphase during mitosis. The smallest chromosome is of 0.25 µ observed in fungi and birds, while the largest in some plants like Trillium is of 30 µ. Nucleosome consists of string of DNA coiled around a core octamer of 8 histone molecules. Neighbouring nucleosomes are connected by linker DNA or spacer DNA which is more exposed to the enzyme. The chromatin fibres are fundamentally consist of large molecules of deoxyribonucleic acid (DNA) and many nucleoproteins. The proteins are of two types i.e., basic histones and non-histone proteins. Histones are structural proteins and non-histones are functional proteins.

Connecting Concepts  The unit of measurement of DNA is a picogram (10–12g). A diploid cell of human being is having 5-6 picogram of DNA (174 cm) and the total amount of DNA in a human being is estimated to be about 100 g having a length of 2.5 × 1010 km.  Histones are rich in basic amino acids. DNA and histones are associated to form nucleoprotein complex. Histones are of five types : H1 Lysine rich H2A   Slightlylysine rich H2B 



H3   Arginine rich H4 

 Histones isolated from different organisms show similarity. They have regulatory function, i.e., responsible for gene activities.  Non-histones proteins: It show great variability and also perform regulatory role.

(a)

(b)

(c)

(d)

Fig. 8.12 Types of chromosomes based on the position of centromere (a) Telocentric (b) Acrocentric (c) Sub-metacentric (d) Metacentric

    

Every chromosome essentially has a primary constriction or the centromere on the sides of which disc shaped structures called kinetochores are present. Based on the position of the centromere, the chromosomes can be classified into four types. The metacentric chromosome has middle centromere forming two equal arms of the chromosome. The sub-metacentric chromosome has centromere nearer to one end of the chromosome resulting into one shorter arm and one longer arm. In case of acrocentric chromosome the centromere is situated close to its end forming one extremely short and one very long arm, whereas the telocentric chromosome has a terminal centromere.

Structure of chromosome 

Each chromosome consists of two coiled filaments throughout its length, called chromonemata. Chromonemata have bead-like structures called chromomers, which are thought to be the gene-bearing portions of chromosomes.



Each chromosome is made of two arms known as chromatids. The two chromatids are connected at the centromere or primary constriciton.

352

BIOLOGY 

The chromonemata are bounded by a sheath called pellicle. Pellicle is present only at metaphase when nucleolus disappears.



Besides primary constriction (centromere), in some chromosomes there is present secondary constriction also and due to this a small portion is pinched off from chromosome body. This portion is known as satellite or trabant. The chromosomes are known as SAT chromosomes. (SAT : ‘Sine Acid Thymonucleinico’ having thymonucleic acid).



Sometimes two satellites are present in a chromosomes, these chromosomes are called Tandem SAT-chromosomes.



SAT -chromosomes are used as marker chromosomes.



The ends of the chromosomes are called telomeres ( which do not unite with any other structure and thus help in maintaining the individuality of chromosomes.

Heterochromatin and Euchromatin 

These terms were coined by Emil Heitz (1928).



Chromosomes are stained with basic dyes like acetocarmine or feulgen (basic fuchsine), two types of regions are distinguished: (a) Heterochromatic region : This region gets dark stain during interphase. This region is generally present towards the end of chromosome and near primary constriction or centromere. This is a genetically inactive region having less amount of DNA. (b) Euchromatin region : This region gets light stain during interphase. This portion is genetically active and rich in DNA.

Giant Chromosomes They are of two types, polytene chromosome and lampbrush chromosome. Polytene Chromosomes : Polytene chromosomes were first reported by E.G. Balbiani in 1881. Fig. 8.13 (A) Structure of a chro-  mosomes (B) A mitotic metaphase chromosomes

They are quite common in salivary glands of insects and are, therefore, popularly called salivary gland chromosomes.



Polytene chromosomes also occur in other organs of insects, antipodal cells (of embryo sac).



The chromosomes can reach a length of 2000 µm and contain 1000 ((Drosophila) to 16000 (Chironomus) times DNA as compared to the ordinary somatic chromosomes.

Connecting Concepts

 The chromosomes in eukaryotes are of two types :   (i) Autosomes : These are more in number and not related with sex of individual. But determine other body  characters.  (ii) Sex chromosomes or Heterosomes or Odd chromosomes or Idiosomes : These chromosomes are concerned with sex. These are of ‘X’ and ‘Y’ type. ‘X’ chromosomes is partly euchromatic and partly heterochromatic whereas ‘Y’ chromosome is heterochromatic. In human males there are X and Y chromosomes whereas in females there are two ‘X’ chromosomes.

Polytene chromosomes are multistranded. They are permanently in prophase stage. The giant chromosomes are formed by somatic pairing between homologous chromosomes and repeated replication (endomitosis) of their chromonemata. All the polytene chromosomes may remain attached to one another at a common point called chromocentre.



Polytene cells cannot divide further. They ultimately die. The adult organs develop from some small-size diploid cells lying nearby.



In certain developmental stages the polytene chromosomes bear conspicuous swellings called chromosome puffs or Balbiani rings.



In the region of a puff or Balbiani ring, the DNA stands uncoil, become active and produce number of copies of messenger or mRNA. The mRNAs may remain temporarily stored in the puff.



Puffs are not permanent. At different physiological or developmental stages different bands uncoil to produce puffs. Puffs are withdrawn after the completion of the stage.



By correlating puffs with different physiological or developmental processes scientists have been able to locate genes on the polytene chromosomes and prepare chromosome maps.

CELL : THE UNIT OF LIFE Lampbrush Chromosomes    

353 Connecting Concepts

 Genome : A haploid set of Lampbrush chromosomes occur in diplotene stage of vertebrate oocytes, spermatocytes chromosomes is called genome (i.e., of Drosophilla and giant nucleus of unicellular alga Acetabularia. number of chromosomes in a gamete), The lampbrush chromosomes are larger than polytene chromosomes. e.g, if a pollen grain of an Angiospermic plant has 8 chromosomes and the stem, Lampbrush chromosomes occur in pairs. The pair consists of homologous chromosomes which are joined at certain contact points leaf and root cells have 16 chromosomes its genome will be 8.

called chiasmata.

 Karyotypes : For cytological studies



Each chromosome has a main axis made of DNA which bear rows of large number of when the morphology of chromosomes chromomeres.



Many of the chromomeres give out lateral projections or loops.

  

of a species is considered as a whole, it called karyotype. Karyotype include (i) Number of chromosomes, (ii) Diameter The lateral loops provide lampbrush like appearance to the chromosome pair. Loops are uncoiled or expanded parts of a chromomere with one to several transcriptional and length of each chromosomes, (iii) Total length of chromosomes, (iv) Ratio units. of short and long arms, (v) Contribution Lateral loops take part in rapid transcription of mRNA meant for synthesis of yolk and of each chromosomes in the total length other substances required for growth and development of meiocytes. of chromosomes.  Idiogram : When the karyotype of any species are represented by a diagram then such diagrams are called idiograms.  Nucleolus is absent in lower genera like yeast and some algae, undifferentiated embryonic cells. Even certain mammalian cells (like reticulocytes, erythrocytes and spermatozoa) lack nucleolus in them. Its absence in lower genera proposes its relatively late development in evolution.

Fig. 8.14 Lampbrush chromosome

Nucleolus 

Nucleolus is a conspicuous, darkly stained spherical body found in nucleoplasm.



The content of nucleolus is continuous with the rest of the nucleoplasm as it is not a membrane bound structure.

 

Nucleolus was first described by Fontana (1781) but name was given by Bowman. The nucleolus is attached to nuclear organizing region (NOR) in the particular nuclear organizing chromosome. It is composed of large amount of ribosomal proteins and ribosomal RNA. The nucleolus stores the rRNA molecules which are synthesized by nucleolar organizer region of DNA (called rDNA). It is site of active ribosomal RNA synthesis. Nucleolus is known as ribosomal factory. Large and more numerous nucleoli are present in cells actively carrying out protein synthesis.

  

Functions of Nucleus  Nucleus is considered as controlling centre of the cell.  Nucleus contains genetic information for reproduction and development of the organism.  Nucleus maintains cell structure and brings about its growth by directing the synthesis of structural proteins.

354

1.

2.

BIOLOGY

Check Point



Nucleus brings about cell multiplication when needed.

Where would the following structures found in a cell ? (a) Microtubules (b) Thylakoids (c) F0 –F1 complex (d) Ribosomes (e) Nucleolus. Which of the following found exclusively in plant cells, animal cells and in both ? (i) Nucleus (ii) Centrosomes (iii) Golgi Bodies (iv) Leucoplasts (v) Cell coat



Nucleus takes part in formation of ribosomes.



Nucleus regulates cell metabolism by directing the synthesis of functional proteins (enzymes).

Connecting Concepts

Plastids 

Plastids are found in plants and few protists ((Euglena). They may be colourless (leucoplastids) or coloured (chromoplastids and chloroplasts).



The term plastid was first used by Haeckel.



The diameter of plastid varies from 4 μm to 6 μm. The variation in size is due to variation in intensity of light available.



On the basis of their pigments plastids are classified into three types i.e., leucoplast, chromoplast and chloroplast.



All types of plastids arise from protoplastids, a sac like non-lamellar structures.

 Plastid inheritance is independent  Different types of plastids may transform from one form to another. But chromoplasts of nuclear inheritance. It has been never transform to chloroplasts. observed in Mirabilis jalapa (4o’clock plant). Leucoplasts or leucoplastids  Interchangeable characteristics of Plastids.

•

Leucoplasts are found in underground parts of plants, internal parts of herbaceous stems and deep tissues of plants where sunlight is not available.

Young ovary (colourless) Leucoplast

•

It is devoid of pigments and internal lamellar structure.

Young fruits (green) → Chloroplasts

•

The leucoplasts usually have storage function.

Mature fruits (red)→ Chromoplasts

•

On the basis of type of food they store; leucoplasts may be called as amyloplast (starch), e.g., potato tuber, wheat and rice grain, aleuroplast (proteins) e.g., maize or elaioplast (oil droplets and fats) e.g., endosperms cells of castor seeds.

In tomato :

In carrot root : Leucoplast → Chromoplast

Connecting Concepts  Different types of chromoplast are present in algae and bacteria. (a) Rhodoplasts : In red algae (rhodophyceae). Chl-a is present along with Chl-d, R-phycoerythrin and R-phycocyanin (phycobilin); pigments forms rhodoplasts. (b) Phaeoplasts : These plastids are found in brown algae (phaeophyceae). Fucoxanthin (brown pigment) is present along with Chl-a and Chl-c. (c) Chromatophores : These are present in blue-green algae and bacteria. Chlorophyll-a, C-phycocyanin and C-phycoerythrin are present in chromatophores of blue-green algae while in chromatophores of photosynthetic bacteria, bacteriochlorophyll (C55 H74O6N4Mg) or chlorobium chlorophyll is present.

Chromoplast •

The colour of flowers, fruits and algae is due to chromoplasts.

•

Chromoplast contains different types of pigments like carotenes, xanthophylls etc.

•

In flowers these plastids help in pollination and in fruits these plastids help in dispersion of seeds because different colours attract insects and birds.

•

Red pigment of chromoplasts i.e., lycopene gives red colour to red chillies and red tomatoes. Lycopene is a type of carotene. Yellowish - orange colours of fruits are due to α-carotene, β-carotene, γ-carotene. β-carotene is precursor of vitamin A. Carrots is the richest source of β-carotene.

Chloroplasts •

Schimper (1983) called green plastids, the chloroplastids. The term chloroplast was proposed by Erera.

•

In plants the chloroplasts are the largest organelle of the cell.

•

Majority of the chloroplasts of the green plants are found in the mesophyll cells of the leaves.

•

These are lens-shaped, oval, spherical, discoid or even ribbon-like organelles having variables length (5-10 mm) and width (2-4 mm).

•

Their number varies from 1 per cell of Chlamydomonas, a green alga to 20-40 per cell in the mesophyll cells of higher plants.

CELL : THE UNIT OF LIFE

355 Connecting Concepts  Shapes, size and number of chloroplasts vary from species to species. Shape may be : (a) Cup-shaped Cup-shaped, Chlamydomonas.

e.g.,

Chlorella,

(b) Girdle-shaped, e.g., Ulothrix. (c) Star-shaped, Zygnema.

Fig. 8.15 Ultrastructure of chloroplast

•

or

stellate,

e.g.,

(d) Spiral-shaped or scalariform, e.g., Spirogyra.

Chloroplast is double membranous structure. Outer membrane posses integral proteins called porins, which make the membrane permeable to solutes of molecular (e) Reticulate or net-like, weight as high as 10,000 daltons. The inner membrane is relatively impermeable. Cladophora, Oedogonium (f) Discoid, Discoid e.g., Vaucheria. Each chloroplast has two parts i.e., grana and stroma.

e.g.,

 In higher plants chloroplasts may



Stroma : The matrix of the chloroplast is known as stroma. It is the enzymatic part of be ovoid, spheroid or disc-shaped but chloroplast. Stroma contains proteins, DNA, ribosomes and fewer amounts of enzymes. mostly they are lens-shaped.



Dark reaction of photosynthesis occurs in this fraction.



Grana : In chloroplast several membranes are arranged in the form of stacks of coins.  In shade plants (sciophytes), 20 to 50 membranous sac like structure called thylakoids. These thylakoids are stacked chloroplasts are larger. In light plants one above the other to form grana. (heliophytes) chloroplasts are smaller.



There are 40 to 100 grana in one chloroplast. Due to presence of chlorophyll in granum  The number of plastid is also variable. lamella, the light reaction of photosynthesis takes place in granum.



Photosynthetic pigment form photosynthetic unit called quantosomes. Each quantosome of many algae, e.g., Chlamydomonas, contains 230 chlorophyll molecules. Park and Biggins discovered quantosomes. Ulothrix, Chlorella.



The granal thylakoids produce 4-8 projections from their margin called stroma thylakoid or fret channel. Fret channels are interlinked with the each other. Weier proposed the  Two to fourteen in Spirogyra.  In higher plants 20-40 chloroplasts concept of grana with interconnecting fret system.



Pigments of chloroplasts

 Size : Generally the size ranges between 4µ-8µ.

 Single chloroplast is found in cells

 Two chloroplast in Zygnema.

(i)

Chlorophyll-a (C55H72O5N4Mg)

(ii) Chlorophyll-b (C55H70O6N4Mg) (iii) Chlorophyll-c (C55H32O5N4Mg) (iv) Chlorophyll-dd (C54H70O6N4Mg) (v) Chlorophyll-e Carotenes   Carotenoids Xanthophyll  Functions (vi)



The chloroplasts help in the biosynthesis of food stuffs by the process of photosynthesis.



Chloroplast help in maintaining balance of CO2 and O2 in the atmosphere.

Mitochondria 

Kolliker (1850) was first to describe muscle mitochondria of insects as sarcosomes. Altmann(1886) called them bioplasts. It was Benda (1897) who introduced the term ‘mitochondrion’ to designate thread like granules. Michaelis (1900) found that they could be stained by Janus Green B.

per cell have been reported.

 The quantasome of bacteria is having only 50 chlorophyll molecules.  Stroma contains osmophilic droplets called plastoglobuli that stores lipids.  Genetic system of chloroplast is called plastidome. DNA in chloroplast is called ctDNA or plastidial DNA.

356

BIOLOGY Connecting Concepts



 Though chloroplasts and mitochondria are under the overall  control of the nucleus of the cell, they possess a great degree of functional  autonomy: 1. They have its own DNA. The DNA is naked. They can show both replication  and transcription. 2. They manufacture some of its  own proteins, enzymes and other biochemicals. As 70S ribosomes are present which can help in translation of coded information contained in mRNAs which was transcribed over chloroplast DNA.

Mitochondria are also called powerhouse of cells. They are large-sized, rounded or rodlike, double-membranous structures. The mitochondria occur singly or in groups and their shape and size (0.5μ to 0.2μ) vary from cell to cell and depend on physiological activity of cell. Total mitochondria in a cell are called as chondriosome. Mitochondria is considered as semi-autonomous organelle because it has separate protein synthesizing machinery independent of nuclear control. The mitochondria are bounded by two membranes i.e., outer membrane and inner membrane. Outer membrane : The outer membrane forms the continuous limiting boundary of the organelle. It bears many non stalked particles known as subunits of parsons. Outer membrane also contains carrier protein that is similar to bacterial porins (proteins) found in gram negative bacteria.

3. New chloroplasts or new mitochondria arise either from division of pre-existing ones or the division of their precursors known as proplastids or promitochondria. In animal cell cristae are plate like while in plant cells these are tubular and called tubuli or microvilli.

Fig. 8.16 Three dimensional structure of mitochondrion

Inner membrane : Inner membrane folded in finger-like projections in the lumen of the mitochondria, known as cristae which increase the surface area.  Inner membrane has less phospholipids and cholesterol as compared to outer membrane.  Many enzymes are found in inner membrane that are involved in ATP synthesis (oxidative phosphorylation). Oxidative phosphorylation is O2 dependent.  Cristae contain different components of respiratory chain phosphorylation. The enzyme system associated with cristae includes a number of dehydrogenases and cytochromes.  The inner membrane bears large number of oxysomes or F0-F1 particle facing the matrix. ATP synthesis occurs in head region of oxysome because of presence of ATPase enzyme. The inner membrane divides mitochondria into two chambers: • Peri-mitochondrial space – The space between outer and inner mitochondrial membrane is known as perimitochordrial space and filled with fluid. • Inner chamber – Inside the inner membrane, relatively dense material called mitochondrial matrix is present. It contain double stranded circular DNA, RNA and ribosomes of 70S types. • Single mitochondria is present in Chlorella fusca (green alga), Microsterias (alga), Trypanosoma, Microsomonas (Protozoans). • Generally, the number of mitochondria varies from 50-50,000 per cell. In some protozoans the number reaches upto 5,00,000. • Largest mitochondria are found in Rana pipens (20-40μ) • Smallest mitochondria are found in yeast ( 1000 Daltons as molecular weight.) The average carbohydrate requirement in adult is ~ 400g per day which provides about 50-70% of total energy.  Essential elements in the constitution of carbohydrate – C. H. O  General Formula – *Cx ( H2O)y (Containing more than one-OH groups). The polyhydroxy aldehydes or ketones can also be called as saccharides  80% of dry weight of plant is carbohydrate. 3-categories/classes : 1- Monosaccharides 2- Oligosaccharides 3- Polysaccharides (1) MONOSACCHARIDES They are simplest carbohydrates, with 3 to 7 carbon atoms. All are reducing sugars with free aldehyde (– CHQ) or ketone (– CO) groups. (i) 3-carbons – TRIOSES (C3H6O3) – e.g. Glyceraldehyde (aldose) and Dehydroxyacetone (ketose) (Acetic acid (CH3COOH/ C2H4O2)and Lactic acid are not considered as carbohydrates) (ii) 4-carbons – TETROSES (C4 H8 O4) – e.g. Erythrose - an aldose (forms raw-material for lignin) (iii) 5-carbons – PENTOSES (C5 H10 O5) – e.g. Ribose (present in RNA, ATP and vit. B2), Xylose and Arabinose - all aldoses, Ribulose - a ketose. (iv) 6-carbons – HEXOSES (C6 H12 O6) – e.g. Glucose, Galactose, Mannose (All aldosesugars) and Fructose (Ketose-sugar). Alcohol of mannose, called Mannitol, is found in brown algae. (v) 7-carbons – HEPTOSES (C7H14O7) – e.g. Glucoheptose ((Both Pentoses and Hexoses may occur in Ring form and Open chain) Glucose – It is called Blood sugar or Grape sugar and occurs in 2-forms, i.e. D-form ( (Dextro -) and L-form ((Levo-). All naturally occurring sugars are in D-form. It is an aldose sugar. Fructose – It is called Fruit sugar. It is most common sugar in plants. It is sweetest amongst naturally occurring sugars. It is a ketose sugar. (2) OLIGOSACCHARIDES They contain 2 to 10 monosaccharide molecules. (A) Disaccharides – They contain 2-monosaccharides (i) Maltose - It is malt sugar and is formed during germination of starchy seeds. It is a reducing sugar. It contains 2 α - glucose units (with α - 1,4-linkage/glycosidic bond)

BIOMOLECULES : ENZYMES, MINERALS & VITAMINS 6

6

CH2OH 1

4 2

+ 4 OH H O

(α-D-glucose)

CH2OH 5

5 1

3

6

CH2OH

5

5 3

6

CH2OH

383

2

(α-D-glucose)

1

4 3

2

O

1

4 3

2

+ H2O

α(1 4) Glycosidic bond

Maltose

Fig. 9.1 : α-1,4-Glycosidic bond

(3)

1. 2. 3.

4.

(4)

(ii) Lactose - It is milk sugar. It is also reducing sugar. It contains 1α-glucose and 1β-galactose (with β–1,4-linkage/glycosidic bond). Lactose is maximum in human milk. The galactose, produced from milk digestion, is also the constitutent of AgarAgar. (iii) Sucrose - It is the sugar of sugar cane and sugar beet. It is non-reducing sugar as it does not have free aldehyde or ketose groups. It contains 1 α-glucose and 1 β-fructose units. (α - 1- 2 linkage/glycosidic bond) The equimolecular mixture of glucose and fructose is called Invert Sugar which is sweeter than sucrose. (iv) Trehalose - It is a disaccharide (α 1-1 linkage) present in micro-organisms. It is also a non-reducing sugar. (v) Cellobiose - It contains 2 β-glucose units (β 1-4 linkage). It cannot be digested by mammalian enzymes. (B) Trisaccharides - They contain 3 monosaccharides, ex. Raffinose - 1 glucose + 1 fructose + 1 galactose (C) Dextrin – It is also an oligosaccharide and is formed during starch-digestion. POLYSACCHARIDES • They are formed by joining of Monosaccharides (Monomers) by Glycosidic bonds between 1-4 carbon atoms. (In a polysaccharide chain the right end is called ‘reducing end’ and the left end is called non-reducing end) • They are non-reducing and mostly insoluble in water. Two types 1. Storage polysaccharides – e.g. Glycogen and Starch 2. Structural polysaccharides – e.g. Cellulose and Chitin Glycogen - It is present in animals (also called animal starch). It is a branched chain compd. and has about 30 α-glucose units. It gives ‘red colour’ with iodine solution. Starch - It is present in plants. The natural starch contains a mixture of amylose (1020%) and amylopectin (80-90%), latter branched and insoluble in water. It also contains all α-glucose. (Amylose in starch is responsible for ‘deep blue colour’ with iodine) Cellulose- It contains all β-glucose. It is most abundant organic compound in biosphere It is a fibrous polysaccharide and forms cell wall in plants. It forms roughage in human food. It is straight chain (unbranched) compound. It form 25 to 50% of wood and about 90% of cotton. Each molecule of cellulose contains about 6000 units of monosaccharides (glucose) and hence is Homoglycan hexosan. Rayon, an artificial and regenerated fibre, is produced from cellulose. Chitin - It forms exoskeleton, mainly in arthropods. It is also present in the cell wall of fungi. Its unit is β-N- Acetylglucosamine. It is a homopolymer. The polysaccharide Agar has more than one type of Monosaccharide units (hence Heteroglycan). The polysaccharide Inulin (Dahlia starch) is a polymer of fructose ( (Homoglycan ) with β-1,2 linkage. CONJUGATED or COMPLEX CARBOHYDRATES – They contain carbohydrate with non-carbohydrate units 1. Glycoproteins – e.g., Blood antigens, Collagen, Lens protein, Blood protein, Hormones like FSH, LH, TSH, hCG, and in cell membranes. 2. Glycolipids - e.g., Blood antigens, nerve fibres and cell membranes

Check Point 1. Fill in the blanks with suitable word/words : (i) ............. elements constitute 93% of protoplasm. (ii) The maximum organic compound in nature is ............. (iii) ............. is a common ketose sugar. (iv) In maltose the glycosidic bond is formed between ............. and ............. carbons. (v) Amongst the naturally occurring sugars ............. is the sweetest one. (vi) ------------------- is the storage polysaccharide. (vii) -------------------is a disaccharide with 2 β-glucose units. (viii) The polymer of fructose is ---------------. (ix) ---------------- is the pentose sugar of nucleic acid. (x) A straight chain polysaccharide.

Connecting Concepts  In ruminants (e.g. cows, sheep etc.) the cellulose is digested by bacteria and protozoans in stomach, whereas in other herbivores (e.g. Rabbit) it is digested by bacteria in large intestine. Termites digest cellulose of wood with the help of Trichonympha (a symbiotic protozoan).

384

BIOLOGY 3.

Mucopolysaccharides – e.g., Heparin. Hyaluronic acid, Synovial fluid, Vitrous humour, Cell wall in bacteria and Mucilages ( Galactose and mannose). They are also present in Bhindi (Lady’s finger) and Isabgol Glucose Test – Benedict’s test, Fehling’s test.

LIPIDS The term ‘Lipid’ was given by a German biochemist, Wilhem Bloor (1943) for fats & fat-like substances. Lipids are non-polymers, micromolecules. They provide about 30% of calories in daily diet. Their requirement is about 50g. in daily diet (in adult of 60 Kg.) Lipogenesis, i.e. synthesis of lipids, occurs in liver and adipose tissue Excess of fat in diet is harmful Fat prevents rapid emptying of stomach The rise of blood fat after meal is called Lipaemia Essential constituients (elements) – C, H, O 3 classes - 1. Simple lipids 2. Compound lipids 3. Derived lipids SIMPLE LIPIDS (Homolipids) - They are esters of fatty acids with various alcohols a. Neutral Fats - e.g. Oil, Butter, Margarine, Ghee etc.  Esters of fatty acids with glycerol.  3-fatty acids are attached to a C-atom of glycerol (forming triglyceride) by Ester linkage (a weak bond, which is broken on heating).  Specific gravity of solid fat is 0.86. that’s why fatty people float easily in water.  The fats that are liquid at room temp. (200 C) are called OILS, i.e. Ground nut oil, Mustard oil, Til oil and Safflower oil. The oils contain Unsaturated fatty acids which on hydrogenation form saturated fatty acids or GHEE.  They are all straight chain compounds and are also called as Neutral Fats.



om

       

Fattyacid

Glycerol (Head)

Fattyacid

Three fatty acids (Tail)

or

ed

ic

al

ac

ad

G L Y C E R O L

em

y.

bl

og

sp

ot

.c

(1)

Fattyacid

tm

Fig. 9.2 : Triglyceride (neutral fat) molecule

tp s:

//n ee

H

H

H – C – OH

H OOC . R

H – C – OOCR

H – C – OH

H OOC . R

H – C – OOCR

H – C – OH

H OOC . R

H – C – OOCR

ht

H 1-glycerol

H 3-fatty acids

1-Triglyceride

Fig. 9.3

b.

Waxes - e.g. Paraffin, Bee wax, Sebum  Esters of fatty acids with alcohol, higher than glycerol. ((Alcohol in waxes have only one hydroxyl group compared to 3-in glycerol glycerol)  All are straight chain compounds  They form water proof coating on skin, hair, leaves and fruits etc.  Bacteria that cause Leprosy and Tuberculosis also produce a wax (wax-D) that contributes to their pathogenicity.

BIOMOLECULES : ENZYMES, MINERALS & VITAMINS

385

Bee-wa (Hexacosyl palmitate), produced by honey bees, is a combination of Bee-wax palmitic acid (fatty acid) with Hexacosonol (alcohol).  Sebum is a mixture of waxes and triacylglycerols. It prevents the growth of certain bacteria on skin. It also prevents the loss of water from the skin. c. Sterols - e.g. Ergosterol and Cholesterol  It is a 4 - ringed structure ( 3-cyclohexane ring and 1-cyclopentane ring )  Cholesterol is found only in animals. Ergosterol is found in plants Fig. 9.4 : Ring structure of steroid  Cholesterol is the precursor of steroid hormones (e.g. Testosterone, progesterone and cortisol) and Bile salts (of cholic acid). It is abundant in nerve tissue and gall-stones.  Sterols are NOT straight chain compounds. COMPOUND LIPIDS (Heterolipids) - Lipids with non-lipid part (also called, Conjugated lipids) A. Phospholipids - e.g. Lecithin (present in cell membranes and detergents) Check Point They are constructed like a neutral fat, except that in place of 3rd fatty acid, there 1. Differentiate between : is a phosphate group. The phosphate group with glycerol becomes polar head (i) Phospholipid and glycolipid (Hydrophilic) of the molecule while hydrocarbon chains of fatty acids become the (ii) Oil and Ghee (iii) Sterols and waxes non-polar tails (Hydrophobic). When phospholipid molecules are placed in water, (iv) Saturated and unsaturated they form double layer in which the polar heads face outward and non-polar tails face fatty acids. each other. This property of phospholipid produces separation between 2-solutions, (v) Essential and non-essential same is the case of plasma membrane of cell. fatty acids. The monolayer of phospholipid reduces surface tension of water. This is important to (vi) Chitin and keratin (vii) Aldose and ketose inflate alveoli. The children who cannot produce phospholipids/ lecithin (here called (viii) First class and second class surfactant) in their alveoli at birth, suffer from ‘Respiratory distress syndrome’ proteins and need a lot of effort to overcome surface tension of water layer on alveoli. Such (ix) Melting and Annealing of DNA infants are kept in ICU till they start producing lecithin. (x) Kwashiorkar and Marasmus (xi) Achiral and chiral amino acids B. Sphingolipids – They are also present in cell membranes and are comparable to (xii) Good and bad cholesterol phospholipids except that sphingosine is present instead of glycerol. Each sphingolipid molecule has a hydrophilic (water soluble) ‘head’, and one-longer and one-shorter hydrocarbon tails. 

(2)

heads in hydrated protein layer hydrocarbon chains of one layer attracted to those of the other layer

Fig. 9.5 : Phospholipid bilayer

hydrocarbon chains sphingosine phosphorylated (head)

Sphingolipid

hydrocarbon chains sphingosine

oligosaccharide of galactose or glucose

Glycolipid

Glycolipids – They are similar to sphingolipids except that oligosaccharide (of glucose/ galactose) is bonded to sphingosine instead of the phosphoric acid. The oligosaccharide (head) is water soluble. Hence, their properties are similar to sphingolipids. ex. A & B antigens in ABO system of blood group. Galactocerebroside is the main glycolipid in the myelin sheath. DERIVED LIPIDS - e.g. Monoglycerides, Diglycerides, Steroids, Terpenes and Carotenoids etc. They are formed by hydrolysis of fats. C.

(3)

FATTY ACIDS They usually contain even number of carbon atoms. (eg. 14 C, 16C and 18C etc) a. Unsaturated fatty acids  They have one or more double bonds between C-atoms  e.g. Oleic acid (one double bond), Linoleic acid (2-DB), Linolenic acid ( 3-DB) and Arachidonic acid (4-DB). The first 3-fatty acids are 18-C, compounds whereas Arachidonic acid is a 20-C, compound.

386

BIOLOGY (Prostaglandins (Pr Prostaglandins, which participate in allergy, inflammatory and other reactions, are derivatives of Arachidonic acid) (Unsaturated fatty acid-chains bend at double-bond and do not fit closely together, resulting in lowering of Melting point, and hence are liquid at room temperature-e.g. oils) b. Saturated fatty acids  They do not have double bonds between carbon atoms  e.g.Acetic acid, Propionic acid, Butyric acid, Palmitic acid, Stearic acid etc. Essential fatty acids –  They are not synthesized in the body  All are Polyunsaturated (with more than 1-double bond), so called PUFA (Poly unsaturated fatty acids).  e.g. Linoleic acid ( in corn, pea and cotton), Linolenic acid (In Linsid oil and pea nut oil). (Margarine has high content of polyunsaturates. Mustard oil is one of the most unsaturated oil; sunflower oil is rich in linoleic acid; and coconut oil has minimum fatty acid content) (Arachidonic acid can, however, be synthesized in body from linolenic acid) Human body - fat contains 50% Oleic acid, 25% Palmitic acid, 10% Linoleic acid and 5% Stearic acid. Connecting Concepts

The carbon atoms of fatty acids are numbered starting from the carboxylic (–COOH) group. However, the carbon atoms may be numbered, starting from methyl group, as Omega (ω) 1, 2, 3 etc. 6

5

4

3

2

1

C H3 − C H 2 − C H 2 − C H 2 − C H 2 − C OOH ω1

ω2

ω3

ω4

ω5

A saturated fatty acid Amongst unsaturated forms (with double bonds), there are 3-families of Omega (ω) fatty acids. 1. ω3 -family eg. Linolenic acid 2. ω5-family eg. Linoleic acid and Arachidonic acid 3. ω9-family eg. Oleic acid Linolenic acid (a 18-C compound) belongs to ω3 family since its first ‘double bond’ begins from ω3 carbon. CH3 − CH 2 − CH = CH − CH 2 − − − − − − − − − − − − − − − − − − − COOH ω3

The omega (ω)-3 unsaturated fatty acids, present abundantly in fish oil, are of great nutritional value, and are required for proper mental growth especially of the ‘grey matter’. Test for Lipids - (1) Grease Spot Test (2) Sudan III (black) or Sudan red test Functions  Poor conductor of heat (For Insulation)  Shock absorber  Food storage (Its primary function) Metabolism of fats β-oxidation : It is the conversion of fatty acids into Acetyl Co-A. The fatty acids through Acetyl Co-A enter Kreb’s cycle. The glycerol enters Kreb’s cycle at PGAL. The oxidation of fatty acids requires more 02 ( R.Q. = 0.7). In shortage of carbohydrates or oxygen, the ketone bodies are formed.

BIOMOLECULES : ENZYMES, MINERALS & VITAMINS Problem : How many ATPs will be produced in β-oxidation and complete oxidation of palmitic acid (16-C, compound) (i) 2-ATP are used in conversion of Palmitic acid into palmitoyl Co-A. (ii) 1 mol. of Palmitoyl Co-A (16-C, compound) produces 8 mol. of Acetyl Co-A (2-C, compound), and 7 molecules (due to 7-cleavages), each of FADH2 and NADH. (iii) Each FADH2 produces 2-mol. of ATPs, and each NADH produces 3-mol. of ATPs. (iv) So, total ATPs produced will be (I) 2 ATPs × 7 = 14 ATPs (II) 3 ATPs × 7 = 21 ATPs TOTAL : 35 ATPs (v) Since 2-ATPs are used in the conversion of palmitic acid into palmitoyl Co-A [see Step (i)]. So net. ATPs produced will be = 35 – 2 = 33 ATPs Ans. For short cut = [(No. of cleavages × 5) – 2] (No. of cleavages = One less than half the number of carbon atoms in the fatty acid) On complete oxidation each acetyl Co-A will produce 12-ATPs, and net production of ATPs (on complete oxidation of Palmitic acid) will be = 33 ATPs + (12 ATPs × 8) = 33 + 96 = 129 ATPs Ans.

Fat Metabolic Disorders 1. 2.

Gaucher’s disease - Autosomal recessive. The liver and spleen are enlarged. Erosion of long bones and Mental retardation occur. Tay Sach’s disease (Infantilc amaurotic idiocy) - Autosomal recessive. Mental retardation, Blindness and Death by the age of 3 years.

PROTEINS Term ‘protein’ was given by Berzelius and Mulder. The proteins are all Heteropolymers (The homopolymers have only one type of monomer)  The proteins provide ~15% of calories in daily diet, with requirement of Ig protein per kg. body weight (60 g. in 60 Kg. person).  Most abundant protein of vertebrates is Collagen (> 30%)  Proteins are most diverse chemicals (Macromolecules) in the living organisms.  Proteins contain C, H, O, N. Some contain S (Sulphur) and P (Phosphorus) also. The structural unit of protein is Amino acid acid.  They are polymers and contain more than 100 amino acids, with one or more polypeptide chains.  They are synthesized in the body from 20-types of amino acids only.  Amongst proteins , The ‘Collagen’is the most abundant protein of animal word; while ‘RubisCO’ (Ribulose Bisphosphate Carboxylase - Oxygenase ) is the most abundant protein of Biosphere. First Class proteins –  They have high biological value and contain all essential amino acids, e.g. Animal proteinslike Milk, Egg, fish and mutton etc. Second Class proteins –  They have low biological value and are deficient in one or more essential amino acids, e.g. Vegetable proteins like Glutein in wheat ( Lysine absent), Zein in Maize (Lysine and Tryptophan absent). Soyabean and Rice, however, have 1st class Protein. Structure of Proteins – The proteins may have Primary, Secondary, Tertiary or Quaternary structures.  

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In Primary structure only Peptide bonds are present between amino acids. The first (or left) amino acid is called N-terminal (–NH2) amino acid, and the last (or right) amino acid is called C-terminal (–COOH gp.) amino acid . Such proteins are not functional proteins.

H

O

+ N – C – COOH

H2 N – C – C R

H R

OH

H H

H O H2 N – C – C R

R N – C – COOH + H2O H H

Peptide bond Fig. 9.6 : Peptide or Amide bond

In Secondary structure, besides peptide bonds, Hydrogen bonds are also present in polypeptide chain. Such proteins may have helical or pleated structures. (A) α-helix (right handed screw) – It is the most common form and is also known as 3.613 helics, since each turn of the helic has ~3.6 amino acids, and a 13-member ring is formed by H-bonding. All amino acids in such polypeptide chain have L-configuration and, it therefore can result in stable helics only if it is Rt-handed. eg. : Keratin in exoskeleton of mammals. (B) Pleated structure – In this structure the polypeptide chains are held side by side by H-bonds- resembling pleated folds of drapery. Such structure is known as β- pleated sheet. The polypeptide chain may be parellel or antiparallel. e.g. Keratin protein in birds (β sheets parallel) and silk protein (fibroin) with antiparallel β sheets. 3. The Tertiary structure may result from further folding and coiling, and may be stablized by S-S (disulphide) bond, Hydrophobic bonds and Ionic bonds. Such proteins are 3-D structures and have two major molecular shapes, i.e. Fibrous and globular. Fibrous proteins – Silk, collagen, elastin and keratin Globular proteins – Albumin, Globulin and Protamine 4. In Quaternary structure, more than one polypeptide chains are involved to form a large multiunit protein. e.g. Haemoglobin. ((In Proteins the peptide bonds and disulphide bonds are strong bonds whereas hydrogen bonds and hydrphobic bonds are weak bonds.) Types of Proteins – Simple proteins, Conjugated proteins and Derived proteins 1. Simple Proteins  Composed of amino acids only.  Soluble or insoluble in water.  Structurely 2-types – Globular and fibrous.  Simple proteins include Albumins, Globulins, Protamines, Prolamines, Lectins and Scleroproteins. The Albumins and Protamines are water soluble. The Albumins are coagulated by heat while protamines are not coagulated. Protamines contain large number of arginine and lysine amino acids, and so are strongly basic. Prolamines are rich in proline but lack lysine. The fibrous proteins (scleroproteins) include collagen and Keratin etc. 2. Conjugated Proteins  Formed by the binding of simple protein with a non-protein part ((Prosthetic group)  They are classified on the basis of prosthetic group. (i) Glycoproteins – Proteins combined with carbohydrates. (When the carbohydrate content is more than 10%, the viscosity is increased and such conjugated proteins are called Proteoglycans or mucoproteins). e.g. Hormones, FSH, LH, TSH and HCG, Blood group antigens, Serum protein etc. (ii) Lipoproteins – Proteins combined with lipids, e.g. Cell membrane and chylomicrons, LDL (Low density Lipoproteins) and HDL (High density lipoproteins) etc. (The cholesterol is carried in soluble form as HDL & LDL). The HDL is ‘good cholesterol’ for health. Its normal value in human plasma is 30-70 mg/100 ml. (less than 30 mg/100 ml. is risky for cardio-vascular problems). The LDL (Low Density Lipoprotein) is ‘bad cholesterol’. Its normal value in human plasma is 80-170 mg/100 ml. (more than 160 mg/100 ml is risky). 2.

BIOMOLECULES : ENZYMES, MINERALS & VITAMINS (iii) Nucleoproteins – Proteins attached to nucleic acids, e.g. Histones in chromosomes ((Histones are basic proteins, i.e. rich in basic amino acids – lysine and arginine). (iv) Phosphoproteins – Proteins containing phosphorous as prosthetic group, e.g. Casein of milk and Vitellin of egg –yolk. (v) Metalloproteins – Proteins with metal ions, e.g. Tyrosinase (copper), Carbonic anhydrase (zinc), Cytochrome (iron), Insulin (zinc) and Trypsin etc. (vi) Chromoproteins - Proteins with pigment or coloured prosthetic group, e.g. flavoproteins (yellow), haemoglobin (red), visual pigment (purple) etc. 3. Derived Proteins - They are produced during hydrolysis of proteins, eg. Proteoses and Peptones. Tests for proteins (1) Biuret Test  NaOH and CuSO4 solutions give reddish – violet colour with proteins  It is test for peptide link (CO – NH)  It is the test for all proteins, peptones and peptides (2) Xanthoproteic Test  Concentrated HNO3 gives yellow colour with the proteins.  It is the test for proteins which have at least one aromatic amino acid acid. (3) Millon’s Test is also used for proteins. Functions of Proteins  Formation of cells and tissues for growth  Repairing of tissues  Formation of hormones  For muscle contraction (eg. Actin , Myosin)  Formation of enzymes  Help in blood clotting  For transport (eg. Haemoglobin, transferrin)  For defence against infections (antibodies).  Form hereditary material – Nucleoproteins  For storage (eg. Myoglobin and Ferritin)  For support (eg. Collagen and Elastin) Protein Deficiency Disorders (a) Kwashiorkar – It occurs in children of below 5-years age and is due to protein deficiency. The symptoms include Tissue oedema (pot-bellied), dark skin, reddish hair and mental retardation. (b) Marasmus – It is due to protein and calorie deficiency. There is No oedema, No dark pigmentation but muscle – wasting occurs. It develops in children of age 1-2 years. It is primarily a Starvation disease. Both Kwashiorkar and Marasmus are PEM (Protein Energy Malnutrition) diseases.

AMINO ACIDS  

The amino acids are ‘structural units ‘as well as’ digestive end products’ of proteins. Chemically they are substituted methanes. All contain atleast 1-Amino group and 1- carboxylic group. R |

H 2 N − C α − COOH |

H

Basic structure of an Amino acid (‘L’−form)

 

Most of the amino acids are amphoteric in nature (with one amino group and one carboxylic group). The ionizable nature of amino (–NH2) and carboxylic (–COOH) groups into NH3+ and COO– make the amino acid ‘Zwitterionic form’.

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Amino acids are of 2 types 1.

STANDARD AMINO ACIDS The standard amino acids (only α-amino acids) are the ones which participate in protein formation and are of L-form. The non-standard do not form proteins, but participate in many important metabolic reactions. The Standard amino acids are 20 in number. Except ‘Glycine’ all other amino acids are Levorotatory – A. Essential Amino acids  The essential amino acids can not be synthesized in the body and are, therefore, required in daily diet.  They are TEN in number, out of which TWO are semiessential, i.e. Arginine (Arg) and Histidine (His). (Arginine is essential only in infants and children).  The other EIGHT, very essential, amino acids are 1. Isoleucine (Ile) 2. Leucine (Leu) 3. Lysine (Lys) 4. Methionine (Met) 5. Phenylalanine (Phe) 6. Threonine (Thr) 7. Tryptophan (Trp) 8. Valine (Val) Tryptophan is the most complex amino acid and has ‘Indole ring’. B. Non-essential Amino acids –  They can be synthesized in the body.  The non-essential amino acids are also TEN in number. They are 1. Alanine (Ala) 2. Asparagine (Asn) 3. Aspartic acid (Asp) 4. Cysteine (Cys) 5. Glutamic acid (Glu) 6. Glutamine (Gln) 7. Glycine (Gly) 8. Proline (Pro) 9. Serine (Ser) 10. Tyrosine (Tyr) Aspartic acid and Glumatic acid are acidic amino acids with two carboxylic groups and one amino group. The Asparagine and Glutamine are their amides. Arginine, Lysine, Histidine are basic amino acids with two amino groups and one carboxylic group. The 20-amino acids can also be categorized on the basis of side chain ‘R’, as (i) Hydrophilic or Polar Amino acids 1. Asparagine 2. Cysteine 3. Glutamine 4. Glycine 5. Serine 6. Threonine 7. Tyrosine (ii) Hydrophobic or Non-polar Amino acids 1. Alanine 2. Isoleucine 3. Leucine 4. Methionine 5. Tryptophan 6. Proline 7. Phenylalanine 8. Valine (iii) Acidic Amino Acids 1. Aspartate (Aspartic Acid) 2. Glutamate (Glutamic Acid) (iv) Basic Amino acids 1. Arginine 2. Histidine 3. Lysine ((Arginine Arginine is the most and Histidine is the least basic amino acid acid))  Glycine is the simplest amino acid. It is sweet in taste and acts as a Neurotransmitter also. The side chain in glycine is represented by H (Hydrogen) atom (not alkyl group). Due to 2-opposite H-atoms this amino acid is symmetrical or Achiral. All other amino acids are assymetrical or chiral, and can exist as D- and L-stereoisomers.  Phenylalanine, Tyrosine and Tryptophan contain benzene ring and so are Aromatic amino acids. (Tyrosine is formed in the body from Phenylalanine).  Proline, a cyclic amino acid, is also called as Imino acid.  Serine and Threonine are hydroxyl amino acids.  The amino acids Cysteine and Methionine, contain Sulphur.

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The different amino acids are attached through – CO-NH bond, called Peptide bond or Amide bond bond.  More than 200 amino acids are known in nature. Important peptides – GLUTATHIONE – It is a tripeptide (with 3 amino acids) having Glycine, Glutamic acid and Cysteine OXYTOCIN AND VASOPRESSIN – They have 9-amino acids each BRADYKININ – It has 9-amino acids. It is most potent pain-producing substance whch mediates prostaglandins. ANGIOTENSIN – Angiotensin-I with 10 amino acids and Angiotensin-II with 8 amino acids are vaso constrictors. 

2.

NON-STANDARD AMINO ACIDS - e.g. Ornithine, Histamine, Citrulline, Thyroxine etc.

NUCLEIC ACIDS (DNA & RNA)   

They are ‘Informational molecules’ of universal occurrence. Present in all cells and viruses. They are ‘polymers of nucleotides’ and hence Macromolecules. (The structural unit of nucleic acids is Nucleotide).

Chemical Structure of Nucleic Acid The nucleic acid on hydrolysis yields 1–Pentose Sugar, 2-types of heterocyclic nitrogenous bases ((Purines and Pyrimidines) and phosphoric acid. Nucleic Acid

Check Point

Purines

Pyrimidines

DNA

Adenine and Guanine

Cytosine and Thymine

RNA

Adenine and Guanine

Cytosine and Uracil

6

5

1N 2

NH2

N7

O N

N

N

8

N 4 N 9 3 Purine Ring

1. Name the followings: (i) Most abundant protein in the body. (ii) Blood protein with quaternary structure. (iii) Semi-essential amino acids. (iv) Acidic amino acids. (v) Metal ions in tyrosinase. (vi) Imino acid (vii) Two aromatic amino acids (viii) High energy bond in ATP (ix) RNA with clover leaf structure (x) Left handed DNA

N N

N

NH2

Adenine

N

N

Guanine

I. PURINES NH2

4 3N

5

O

N

O CH3

N

N

2

6 N 1 Pyrimidine Ring

O

O

N Cytosine

N

O

Thymine

N Uracil

Fig. 9.7 : II. Pyrimidines

Following are the important differences between DNA & RNA DNA RNA 1.

Double stranded

1.

Generally single stranded

2.

Sugar-Deoxyribose

2.

Sugar-Ribose

3.

Pyrimidines - Cytosine and Thymine 3.

Pyrimidines – Cytosine and Uracil

4.

Cytosines are equal to Guanines

4.

Cytosines are not equal to Guanines (being single stranded)

5.

Base pairs usually 100 to 5000

5. Base pairs in millions

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BIOLOGY

5 CH2OH

O

H

4 H H 3 OH

1 H OH 2 OH

Ribose (Sugar)

5 CH2OH

O

4 H H 3

H 1 H OH 2

OH

H

Deoxyribose (Sugar)

Fig. 9.8 : Sugars in Nucleic Acids

Connecting Concepts

DEOXYRIBONUCLEIC ACID (DNA)

 Mitochondrial DNA (mt DNA) is Mainly localised in nucleus. circular and contains about 16,500   Small amount of D.N.A. is also present in Mitochondria and Chloroplast. nucleotides. It has information for synthesis of 2 – rRNA and 22-tRNA. It is inherited from mother through female Nucleosides gamete. It also has low mutation The combination of pentose sugar with nitrogenous bases (Purines or pyrimidines) is called rate but does not show genetic nucleoside. recombination.

i.

ii.

Nucleosides of purines Adenine – Adenosine Guanine – Guanosine Neucleosides of pyrimidines Cytosine – Cytidine Thymine ( in DNA ) – Thymidine Uracil (in RNA) – Uridine

Nucleotides Phosphate ester of a neucleoside is called neucleotide. Each nucleotide consists of nitrogenous base, pentose sugar and one or more phosphate groups. i.

Neucleotides of purines Adenosine + 1-phosphate group – Adenosine Monophosphate (AMP) or Adenylic acid Adenosine + 2-phosphate groups – Adenosine Diphosphate (ADP) Adenosine + 3-Phosphate groups – Adenosine Triphosphate (ATP) Guanosine + 1-phosphate group – Guanosine Monophosphate (GMP) or Guanylic acid

ii.

Nucleotides of Pyrimidines Cytidine + 1-phosphate group - Cytidine Monophosphate (CMP) or Cytidylia acid Cytidine + 2-phosphate groups – Cytidine Diphosphate (CDP) Cytidine + 3-phosphate groups – Cytidine Triphosphate (CTP) Thymidine + 1 Phosphate gp. - Thymidine monophosphate or Thymidylic acid Uridine + 1 phosphate gp. - Uridine monophosphate or Uridylic acid In case of Deoxyribose sugar (of DNA) the above names are preceded by ‘d -’ , i.e. dAMP – Deoxy Adenosine Monophosphate dTDP – Deoxy Thymidine Diphosphate Nucleic acids (DNA & RNA) are polymers of the nucleotides (Nucleoside monophosphate) The nucleotides are acids and are negatively charged at neutral pH. The carbons of pentose sugars are primed as 1’ , 2’ , 3’ , to distinguish them from the carbons of nitrogenous bases.

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Connecting Concepts

ATP (Adenosine Triphosphate) is also a nucleotide. It contains 1-Adenine base, 1-Ribose sugar and 3-phosphate bonds. It is energy-rich compound, and is also called as ‘energy currency’. Its II and III bonds are energy rich bonds, each releasing 31 kJ energy per mol. PO4

III

II

PO4

PO4

I

5

C

O

Adenine

4

1 3

2

Fig. 9.9 : ATP molecule

Nucleotides are joined together by phosphodiester linkage between 5’ and 3’ carbon atoms of pentose sugar. The chain of nuclic acid is abbreviated from 5’ end to 3’ end, in left to right order. A O

3'

T

4'

1' 2'

P

C O

4'

4'

G 3'

2' 1' O

3'

G

P

3' Sugar 5' P

5'

2 nm DNA double helical structure

5' Sugar 3' P

4'

C

4'

P

3'

5'

5'

5' end O

P

P

3' end P

3'

1 complete turn with 10 base pairs = 3.4 nm

5' 3'

O

5'

5'

2 Anti-parallel strands

3'

Nitrogenous bases

3' Sugar 5' 5' 3'

Major groove

P

5' Sugar 3'

P

Sugarphosphate back bone

5'

P

5'

4'

Minor groove

3'

3'

Hydrogen bonds

O

5'

2 antiparallel strands with nitrogenous bases

Representation in short-form

– Phosphodiester linkage; A – Adenine (Purine); T – Thymine (Pyrimidine); G – Guanine (Purine); C – Cytosine (Pyrimidine); Fig. 9.10

Edwin Chargaff reported that net amount of adenine was equal to thymine (A = T) and amount of Guanine was equal to cytosine ( G = C ). This means that total number of purines is equal to the total number of pyrimidines (A + G = T + C ). As the base composition in DNA of different species varies, the AT/CG ratio also varies from species to species. AT/CG ratio = 1.52 in human and 0.93 in E .coli.

Double Helical Structure of DNA To explain base equivalence ( A / T, G / C ) and other properties of DNA, Watson and Crick (1953), based on X-ray diffraction studies, proposed double helical structure of DNA. Such structure has 2 right handed helical polynucleotide chains (strands) around a central axis resembling a spiral staircase. The two strands of helical are anti parallel, means 5’  3’ Phosphodiaester bonds (Sugar-phosphate groups) are oriented in opposite direction in 2-strands, i.e., the 5’ end of one strand is opposite to the 3’ end of the other strand. The bases are held like steps (rungs) of spiral staircase by hydrogen bonds. The phosphodiaester bonds (with sugar) form rails or the sides of ladder. These bonds connect 2-nueleotides Between A & T, there are 2 hydrogen bonds (A = T ) and in between C & G there are 3 hydrogen bonds (C ≡ G). The C ≡ G base pair has more stability, due to triple bond, as compared to the A = T base pair.  The diameter of double helical structure of DNA is 2 nm ( 20 Å )

394

BIOLOGY Total distance from 1 base pair to another base pair (step or rise)= 0.34 nm (3.4 Å) Total base pairs in 1 complete turn (pitch) = 10 (in B-type DNA) The distance covered in 10- steps or 10 base pairs or 1 complete turn ((Pitch) = 3.4 nm (34 Å) On the bases of number of base pairs and right or left handedness of helicals the DNAs are of more than 12-forms .The main forms or types of DNA are

  

Types of DNA Type of Helics No. of Base pairs per turn Properties A – Type Rt. Handed 11 B – Type Rt. Handed 10 Most stable and most common form. (Described by Watson and Crick.) C – Type Rt. Handed 1 9 C & D types occur under 3 artificial Conditions D – Type Rt. Handed 8 Lt. Handed Z – Type 12 (6-nucleotides) Sugar phosphate rail is ZigRepeating unit dinucleotide Zag hence named ‘Z’ DNA. Pitch 45Å, diameter 18Å. On heating, the 2-strands of DNA separate from each other (called Melting), and on cooling they again hybridize (called Annealing). The temperature at which the 2-strands separate completely is known as its melting temperature (Tm) which is specific for each sequence. If one sample of DNA has more Tm, this means it has more C ≡ G pairs (having stronger bonds, i.e. 3-hydrogen bonds, difficult to break ).

RIBONUCLEIC ACID (RNA) 1.

2.

3.

It has single helical structure and is mainly of 3-types. m -RNA ( Messenger RNA )  ~ 5% of total RNA  Base sequence complementary to one DNA strand  Length varies according to the length of the polynucleotide used.  Generally exists for a short time.  Life span 1-4 minutes (shortest life)  Number of Nucleotides generally more than 1500, so it is the longest RNA. r -RNA ( Ribosomal RNA )  80% of total RNA.  Base sequence similar in all organism.  Synthesized in nucleolar organizing region (NOR) of the DNA.  Life span several days (longest life)  Most stable RNA The enzyme Ribozyme is also a r-RNA) t -RNA ( Transfer RNA )  15% of total RNA.  Average 80 nucleotides per molecule  Smallest of all RNAs  More than 20 different t-RNA may be present in a given cell.  Easily soluble, so called soluble RNA (s -RNA) also  Transfers amino acid from cytoplasm to the ribosomal machinery.  Acquires Clover leaf structure by folding upon itself. The unusual bases present in tRNA are Dihydrouracil, Pseudouridine and Hypoxanthine etc. ((Feulgan, Aceto-carmine and Aceto-orcein are nuclear stains. Feulgan stain (reaction) is specifically for DNA, as it stains ‘deoxyribose’ sugar).

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Part-II : Enzymes While going through the chapter pay special attention to the following – Definitions – 1. Holoenzyme 4. Co-factor

2.

Km value

Differences – 1. Competitive and non- competitive inhibition 3. Exoenzymes and Endoenzymes Terms – 1. Feed back inhibition

2.

Turn over number

3.

Immobilized enzyme

2.

Hydrolases and lyases

3.

Apoenzyme

Velocity

Velocity

Buchner, a German bio-chemist, discovered enzymes in yeast, and stated that living nature of the cells is not essential for the enzymatic activity. Kuhne coined the term ‘enzyme’ (means in yeast). J. Sumner isolated first enzyme (Urease) in pure crystalline form from Jack beans. Properties of enzymes –  Northrop discovered that all enzymes are proteins. However, RNA, can also act as enzyme, called ribozyme.  Enzymes are oligodynamic, i.e. they are required in small amounts.  They are metabolic regulators.  They act as catalysts in biological reactions and are, therefore, called Biocatalysts.  They are pH specific, substrate specific and temperature specific. The optimum temperature for enzymatic action is ~370C. At 00C the enzymes are inactivated while at 600C or above most of the enzymes are denatured and their enzymatic activity is lost. (The optimum pH for most of the enzymes is 7; but for Pepsin/Rennin and Alkaline phosphotase (in Kidney) it is 2 and 10 respectively). It must be remembered that pH is a log value and a change of 1 on pH scale will cause a 10 fold change in H+, while a change of 2 in pH will produce 100 fold change in H+).  They can not start a chemical reaction but can regulate the velocity of reaction.  They are reusable.  They can not change equilibrium point of a reversible reaction.

0°C

37°C

6

50°C

Temp. Fig. 9.11 : Effect of temperature on Enzyme velocity

8

pH Effect of pH on Enzyme velocity

Enzymes versus Inorganic Catalysts – (1) Similarities  Both can not start a chemical reaction.  Both are oligodynamic.  Both are reusable.  Both can not change equilibrium point of the reaction.

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BIOLOGY (2)

Dissimilarities  Enzymes are complex (protein) compounds while the catalysts are simple and inorganic in nature.  Enzymes are pH, temperature and substrate specific while the catalysts are not so specific.  The activity of the enzymes can be regulated but catalysts’ activity can not be regulated.

Important terms Proenzymes - They are inactive form of the enzymes, eg. Pepsinogen, Trypsinogen Isoenzymes - Two enzymes with similar structure and catalytic activity but differing in some of their chemical properties, e.g. LDH (Lactic acid dehydrogenase or lactate dehydrogenase) and Aldolases LDH is of two types –‘M’ type (in muscles), and ‘H’ type (in heart). The LDH changes lactic acid into pyruvic acid. (3) Lysozymes - These are germicidal enzymes present in sebum, tears, milk and saliva etc. They destroy bacteria by hydrolyzing their cell wall of polysaccharides . (4) Exo-enzymes and endo-enzymes - The enzymes which work outside the cells (eg. digestive enzymes) are exo-enzymes while the enzymes working inside the cells (eg. respiratory enzymes) are called endo-enzymes. (5) Holoenzymes - These enzymes are conjugated proteins. Their non-protein part is called Co-factor.  The co-factor can be inorganic or organic in nature. The organic factor, if permanently attached to the enzymes, is called Prosthetic group and if temporarily attached (only during reaction), is called Co-enzyme :  Haem is a prosthetic group in catalases and peroxidases. NAD and NADP are coenzymes. FAD is co-enzyme in flavo-proteins or yellow enzymes.  Most of the co-enzymes are derivatives of vitamin B & C.  The protein part of holoenzymes is called Apo-enzyme (6) Flavo proteins (Yellow enzymes) – They are holoenzymes with co-factor of Riboflavin (vitamin-B2) (7) Immobilized enzymes - These enzymes are used in industries. They are protected from the action of proteases by attaching them to a solid support or a jelly, or binding them with a covalent bond, or incorporating them into artificial cells. Turn over number – The number of substrate molecules which can be catalyzed by a single molecule of an enzyme in a unit time. A maximum turn over number (36-milion mol. /minute) is of Carbonic anhydrase. The turn over number depends upon the number of active sites. Structure of enzymes The enzymes are tertiary proteins. Active site- It is a specific region in the structure of enzyme to which a substrate (reactant) binds. The Active site has a specific type and number of amino acids. It is a small site and covers nearly 5% of the total area in most of enzymes. In certain cases metal (co-factor) may also participate in the formation of such sites. Theories about enzymatic action – (i) Emil Fisher’s Lock and key hypothesis– According to this theory the active site of enzyme acts as a lock while substrate acts as a key. Fisher believed that active site is rigid or non-flexible. (ii) Koshland’s Induced fit theory – The active site, according to this theory, is flexible, i.e a change can be induced by the substrate, in the configuration of the active site. Enzymatic action –  The energy required for a chemical reaction to proceed is called Activation energy.  The enzymes lower the activation energy. (Remember that enzymes cannot start the chemical reaction) (1) (2)

Connecting Concepts  Primary proteins have only peptide bonds. The secondary proteins with helical or pleated structures, have hydrogen bonds also. The tertiary proteins are formed by further coiling or folding of the polypeptide chain. This form is established by disulphide (S – S) bond.

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With the increase in concentration of substrate the enzymatic velocity also increases. At a certain value all the active site of the enzyme- molecules are saturated and the increase in substrate concentration does not increase the velocity of the enzymatic reaction. (The concentration of substrate at which the velocity of enzymatic action reaches half of its maximum value, is called Km value or Michaelis constant). Higher is the affinity of an enzyme for a substrate the lower is its Km value, 1 i.e. Km value ∝ affinity





Reaction without enzyme

A

Vmax

Reaction with enzyme

½Vmax

Velocity

B C

S

P

D Lowering of Activation Energy by enzyme

Km Substrate Cone (m.mol/lit.) Effect of substrate concentration on Enzyme velocity

S - Substrate

P - Product

C = Energy level of Substrate D = Energy level of Product C to A = Active energy in the absence of enzyme C to B = Active energy in the presence of enzyme A to B = Lowering of activation energy due to enzyme

Fig. 9.12

Inhibition of enzymatic action (1)

(2)

By denaturation If enzyme is heated to 600C or above the tertiary conformation of the enzyme (active site) changes and the property of the enzyme is lost. By competitive inhibition –  A chemical, similar in configuration to the substrate, competes for the active site of the enzyme. eg. Malonate (Malonic acid) competes with Succinate (Succinic acid) for the active site of Succinate dehydrogenase. The malonate is here competitive inhibitor for the synthesis of Fumarate (Fumaric acid) from succinic acid. Succinate dehydrogenase

Succinic acid → Fumaric acid (Succinate)

(3)

(Fumarate)

(The methanol toxicity is similarly averted by ethanol, a competitive inhibitor, for the enzyme alcohol dehydrogenase).  Sulpha drugs compete with PABA (Para amino benzoic acid) for the active site of enzyme present in bacteria. Due to the use of Sulphonamide drugs, like Prontosil, the product- folic acid (a component of vitamin-B complex) is not synthesized by bacteria and the effect, like an antibiotic, is antibacterial. By non-competitive inhibition –  Here the chemical does not compete with the substrate for active site. It binds with the enzyme at the site other than active site.  The inhibitor changes the configuration of the active site or the 3-D shape of the enzyme. eg. Cyanides stop the functioning of the respiratory enzymes by binding with the Iron of the prosthetic group. Ions of Heavy metals (like Hg, Ag and Cu) combine with the disulphide/thiol thiol group and break that to change the 3-D shape of the enzyme, or denature it.

Check Point 1. Differentiate between : (i) Lock and Key theory and Induced fit theory of enzymeaction. (ii) Co-enzyme and co-factor. (iii) Biocatalyst and Inorganic catalyst. (iv) Exo-enzymes and Endoenzymes. (v) Competitive and Noncompetitive inhibition of enzymatic action. (vi) Active site and allostearic site (vii) Isoenzymes and lysozymes (viii) Lyases and ligases

398

BIOLOGY (4)

Allosteric inhibition (Feed back inhibition)–  Allosteric enzymes have Allosteric site with the active site. The chemical binds to this well defined Allosteric site and inhibits the chemical reaction. The inhibitor in such reactions is one of the product of a long chain of enzymatic reactions and hence this inhibition is also known as feed back inhibition e.g. Hexokinase. Binds to Allosteric site Hexokinase

Glucose + ATP

Glucose 6- Phosphate + ADP Fig. 9.13

Connecting Concepts  Each type of enzyme has a specific 4 -integers EC number – 1st Integer designates one of the six major classes of enzymes. The 2nd integer indicates a sub-class. The 3rd integer indicates a classification of the bond or the group transferred. The 4th is a specific serial number.  The 4-integer EC number for Arginase is 3.5.3.1 [it is hydrolase (3), and a non-peptide (5)]. The explanation of the last two integers of the EC number are beyond the scope of this book.

Classification of enzymes (a) On the basis of the substrate – (1) Proteases (Proteolytic enzymes) –They act on proteins/ peptides, eg. Pepsin, trypsin and polypeptidase (2) Carbohydrases (Sucrolytic enzymes) – They acton carbohydrates, eg. Amylase, maltase and sucrase. (3) Lipases (Lipolytic enzymes) - These act on lipids or fats, eg. Steapsin. (b) On the basis of the type of reactions* (1) Oxido-reductases – eg. Oxidase (like Cytochrome oxidase), dehydrogenase (like Alcohol dehydrogenase) (2) Transferases – eg. Phosphorylase, transaminase and hexokinase. (3) Hydrolases – Cause Enzymatic breakdown with the addition of water, eg. Amylase, urease, lipase. (4) Lyases – Cause Enzymatic breakdown without the addition of water, eg. Decarboxylases, Deaminases (5) Isomerases – eg. Aldolases. (6) Ligases (synthetases) – eg. DNA and RNA ligases. (For synthesis of complex molecule from the simpler ones.) *Out of about 2,500 different enzymes named so far, the most abundant group is oxidoreductase. The correct order is 1>2 >4 >3 >6 >5. Enzymes are named according to the classification designed by Enzyme Commission (EC) of the IUPAC ((International Union of pure and applied chemistry). This classification is based on the type of reaction which they catalyze.

BIOMOLECULES : ENZYMES, MINERALS & VITAMINS

399

Part-III : Minerals & Vitamins While going through the chapter pay special attention to the following – Vitamin derivatives 1. FAD 3. Co-enzyme A

2. 4.

NADP T.P.P.

Deficiency disorders 1. Nyctalopia 4. Beri – Beri

2. 5.

Pernicious anaemia Scurvy

3. 6.

Pellagra Rickets

Common names – 1. Anti- haemorrhagic vitamin 2. Vitamin PP 3. Extrinsic factor of Castle The minerals, water and vitamins do not provide energy but help in energy production and maintain proper metabolism of the body. They are called Micro nutrients or Protective principles of food. Their deficiency causes various disorders or diseases.

MINERALS

(a)

(b)

The essential elements or minerals required by animals or human body are 21. On the basis of amount required they can be classified as Macro or major elements/ minerals – 7 Sodium, Potassium Calcium, Magnesium, Phosphorus, Sulphur and Chlorine. The daily requirement of each of these elements is more than 100 mg. Micro elements or Trace elements/ minerals – 14 Iron, Manganese, Iodine, Zinc, Cobalt, Copper, Selenium, Molybdenum, Fluorine, Chromium, Nickel, Barium, Lithium and Bromine. The functions of last 5- elements are not fully understood. In plants the essential elements or minerals are 20. Out of which 10 are required in macro and 10 in micro doses. Sodium, Iodine, Flourine and Selenium, the essential and important minerals in human or animals, are not at all essential for plants. Following disorders are, however, caused due to excess of (certain) minerals I. Siderosis - Due to deposition or excess of Iron (as oxide) II. Wilson’s disease - Due to excess copper, and causes brain damage III. Fluorosis - Due to excess fluorine, and produces yellow patches on teeth.

* VITAMINS   

  

Term ‘vitamin’ was given by Casimir Funk. The Vitamins are organic compounds which are neither carbohydrates, nor proteins nor fats. They are also known as Accessory food factors, and are required in small amounts (in micro grams or IU = International Units [1 IU = 0.3 micrograms (0.3 µg)]).Vitamin C is however, required in macro doses. They are not pH specific. They have no calorific value. They are also called growth regulators or metabolic regulators. Vitamins can be classified into 2- categories - (i) Fat soluble vitamins (ii) Water soluble vitamins

* Vitamins are not included in NEET Syllabus.

400

BIOLOGY (1)

FAT SOLUBLE VITAMINS – Vitamin-A, D, E and K 

They are taken as precursors or pro-vitamins.



For their absorption, the fat is essential in diet.



They can be stored in the body.



Their deficiency disorders are not easily corrected.

Vitamin-A 

Chemical name -

Retinol (A1) and Dehydroxy retinol (A2)



Common name -

Bright Eye Vitamin/ anti infection vitamin/ antixerophthalmic factor



Sources -

Cod/ Shark liver oil, Yellow fruits (Papaya, mangoes) and vegetables (like Carrot), Butter, Ghee and Egg. This vitamin is formed in liver from yellow and red carotenoid pigments β-carotenes.



Functions -

1.

Vitamin A helps in synthesis of Rhodopsin ( visual pigment of rod-cells )

2.

It maintains secretory nature of epithelial lining.

a.

Phrynoderma –rough and keratinized epithelium of skin, respiratory tract and urinogenital tract.

b.

Xerophthalmia – dry eye condition later causing Keratomalacia (def. of vitamin-A1)

c.

Night blindness or Nyctalopia – Inability to see in dim light (def. of vitamin-A2)



Connecting Concepts  Calciferol - a prohormone, synergistic to parathormone, increases the amount of calcium in blood while calcitonin (hormone) decreases the amount of calcium in blood.

Deficiency disorders-

Vitamin - D 

Chemical name -

Calciferol (a steroid ). D2 – Ergocalciferol of plant origin, and D3 – Cholecalciferol of animal origin, the latter is most abundant.



Common name -

Anti-rachitic vitamin/ Poor man’s vitamin/ sunshine vitamin.



Source -

Fish liver oil, Liver, Egg, Milk, Ghee (Commercially this vitamin is obtained from a fungus, Ergot). In human skin this vitamin is synthesized from 7-dehydrocholesterol, an intermediate of cholesterol biosynthesis.



Functions -

Helps in absorption of calcium ions from intestine and is important for the growth and maintenance of bones and teeth.



Deficiency disorders-

1.

Rickets (Bow-legged) in children

2.

Osteomalacia in adults (bones become weak and soft)

(Osteoporosis, also a bone disorder, is caused due to hypersecretion of parathormone or PTH)

BIOMOLECULES : ENZYMES, MINERALS & VITAMINS

401

Vitamin - E Tocopherol



Chemical name -



Common name -

Anti-sterlity vitamin/vitamin of beauty.



Source -

Vegetable oils - Wheat germ oil, sunflower oil, cotton seed oil ((Remember Remember that fish liver oil is devoid of vitamin-E ).



Functions -

It is antioxidant and prevents the oxidation of unsaturated fatty acids. It boosts immune system and reduces the risks of Myocardial infarction by reducing the oxidation of LDL (low density lipo- proteins)



Deficiency disorders -

1.

Sterility (in rats)

2.

Anemia, as RBCs become fragile.

3.

Muscle Degeneration.

Vitamin - K

2.



Chemical name -



Common name -



Source -



Functions -



Deficiency disorders -

K1 - Phylloquinone (a haphthoquinone derivative with a long Connecting Concepts isoprene chain), K2 - Menaquinone.  Ubiquinone or Co-enzyme Q, is Anti-haemorrhagic-Vitamin/coagulation-vitamin also a quinone-derivative with a (Vit-K is Koagulation vitamin- a German word) long isoprene chain. This co-enzyme participates in Electron transport Leafy vegetables (for Vit-K1) chain (ETC) and is reduced to (vit. K2 is synthesized in intestine by micro flora) semiquinone (QH) and finally to A synthetic and water soluble form of this vitamin, which is quinol (QH2). It accepts electrons commercially used, is Menadione. from NADH and FADH2. Its deficiency is associated with several mental It helps in synthesis of Prothrombin and blood clotting factors disorders. No. VII , IX and X. 1. Haemorrhage and delayed blood clotting.

WATER SOLUBLE VITAMINS – Vitamins-B & C  Not taken as provitamin.  Fat in diet is not essential for their absorption.  Not stored in the body except vitamin B12.  Deficiency disorders are easily corrected. Vitamin-B complex – (i) Thiamine (Vitamin-B1) Common name – Anti Beri-Beri vitamin/ Aneuritic vitamin. Connecting Concepts Source – Husk of cereals (whole wheat flour or brown bread).  Chronic alcoholics generally develop thiamine deficiency, and hence Remember that polished rice lacks thiamine. polyneuritis and other disorders. Functions – Acts as co-enzymes (TPP-Thiamine pyrophosphate) in decarboxylation reactions in carbohydrate metabolism. Deficiency disorders – Beri-Beri (a Singhalise word, meaning weakness) with the symptoms of anorexia (loss of appetite), dyspepsia (indigestion with abdominal discomfort) and weakness. The Beri-Beri has 2-forms (1) Dry Beri-Beri - It causes extreme emaciation (weakness) and no Oedema. (2) Wet Beri-Beri - It produces Oedema (accumulation of tissue fluid). Polyneuritis – swelling at nerve endings. The deficiency of thiamine (vit. B1) also causes Fatigue, headache, mental depression and Heart enlargement.

402

BIOLOGY (ii) Riboflavin (Vitamin-B2 or Vit. G) Source -

Milk (Lactoflavin), liver (hepatoflavin) and eggs (Ovoflavin)

Functions -

Acts as co-enzymes (FAD/FMN) in flavo-proteins for oxidative phophorylation.

Deficiency disorders-

Cheilosis (cracks at the end of lips) Photophobia (hypersensitivity to light) Glossitis (fissure on tongue and atrophy of papillae)

Connecting Concepts  Some amount of the vitamin B3 is synthesized from amino-acid Tryptophan. People using maize as staple food are deficient in Niacin because maize does not have this amino acid in usable form.

(iii) Niacin or Nicotinic acid (Vit. B3)

The term ‘Nicotinic acid’ has nothing in common with Nicotine of Tobacco, and therefore, this term is not widely used. Common name -

Vitamin-PP (Pellagra preventive)

Functions -

Acts as co-enzymes in hydrogen transport as (i)

NAD/ DPN/ Co-enzymes-I

(ii) NADP/ TPN/ Co-enzymes-II Deficiency disorders -

Pellagra (rough & scaly skin with dark pigmentation) Diarrhoea, Nausea and vomiting. (Black tongue in dogs.)

(iv) Pantothenic Acid (Vit. B5)

Pantos (Gk word ) means everywhere, shows that the vitamin is widely distributed in nature. Functions -

Acts as a component of Co-enzyme-A.

Deficiency disorders-

Burning foot syndrome and inhibition of fatty acid synthesis. Anemia due to reduced haem synthesis.

(v) Pyridoxine (Vitamin-B6) -

Acts as a co-enzyme (pyridoxal phosphate) in protein metabolism or amino acid metabolism. Deficiency disorder -

Convulsions (Fits) or epilepsy due to non- synthesis of GABA (an inhibitory neurotransmitter)

(vi) Biotin (Vitamin B7 or Vit. H) Common name -

Anti egg – white injury factor.

Functions -

Acts as a co-enzymes in carboxylation reaction. Affinity of avidin (protein of egg-white) to biotin is greater than antigen-antibody reaction, hence it is used in ELISA test also. Good for healthy hair.

Deficiency disorders -

Hair falling and allergy from egg –white.

(vii) Folic acid or Pteroglutamic acid (Vitamin-B9) Folium (Lt word) means leaves of vegetables. Source -

Green leafy vegetables. Milk is a poor source of this vitamin.

Functions -

It participates in the synthesis of nitrogenous bases of nucleic acid, and thus stimulates cell division.

Deficiency disorders -

Megaloblastic or macrocytic anaemia – few but large sized RBCs appear in blood. Impairment of antibodies synthesis.

BIOMOLECULES : ENZYMES, MINERALS & VITAMINS (viii) Cyanocobalamine (Vitamin-B12) –

It is most complex vitamin and contains cobalt. Common name -

Antipernicious anaemia factor/ Extrinsic factor of Castle.

Source -

It is absent in plant products but is present in animal products like – Milk, Egg, fish, liver, meat etc. (In curd Lactobacillus bacteria can synthesize this vitamin). It is also synthesized by microflora of the gut (colon). A blue-green alga (Spirulina) is also known to contain this vitamin.

Functions -

Reduction of deoxyribose from ribose sugar for the formation of DNA from RNA.

403 Check Point 1. Match the items of column I with the items of column II : Column I Column II 1. Pteroglutamic A. Polyneuritis Acid 2. Niacin B. Pernicious anaemia 3. Thiamine C. Osteomalacia 4. Pyridoxine D. Megaloblastic anaemia 5. Calciferol E. Convulsions F. Pellagra G. Osteoporosis

Synthesis of myelin sheath. Deficiency disorder -

(ix) Choline Source Functions -

Vitamin-C– Chemical name Common name -

Source

-

Functions-

Deficiency disorders -

Megaloblastic or macrocytic anaemia, better called Pernicious (injurious) anaemia. This anaemia is associated with mental disorder, since the myelin sheath breaks down interrupting conduction of nerve impulses. Milk, Egg, Liver and vegetables. It is lipotropic factor and forms the part of phospholipids (essential constituent of cell membrane) Prevents fat deposition (neutral fat and cholesterol) in liver. Helps in the synthesis of acetylcholine (the most common neurotransmitter). (B4-Adenine & B8-Adenylic acid are not considered as Vitamins)

Check Point 1. Fill in the blanks : (i) ................... is antiviral vitamin. (ii) ................. prevents blackening of cut-fruits. (iii) The term ‘vitamin’ was coined by ................. (iv) Anorexia, dyspepsia and muscular weakness are the symptoms vitamin .................... deficiency. (v) Deficiency of vitamin ............... causes nyctalopia. (vi) The vitamin .....................is tryptophan derivative (vii) ...................is cobalt containing vitamin (viii) The commercial name of ................. is menadione (ix) Chemical name of vitamin C is .................. . (x) Tocopherol is the chemical name of vitamin ............. .

Ascorbic acid Anti-scurvy vitamin/anti-ageing vitamin/anti-rabies vitamin/ anti-cancer vitamin/anti-viral vitamin. ((Anti-viral nature of vitamin-C was discovered by Linus Pauling, who received Nobel prize for this discovery). Amla, Citrus fruits, Goose berries, Guava and green chilly. (James Lind discovered that citrus fruits can cure Scurvy.) Helps in synthesis of collagen fibres for healing. Connecting Concepts A strong reducing agent (antioxidant).  St. Gyorgyi received nobel prize Prevents blackening of banana and colour-changing of cut for establishing the relationship fruits. between the hormones of adrenal cortex and vitamin-C. Promotes synthesis of hormones of adrenal cortex. Scurvy (spongy and bleeding gums). Capillaries rupture due to lack of cementing material and healing is delayed.

404

BIOLOGY

EXERCISE - 1 | NCERT BASED QUESTIONS 1.

2.

3.

4.

5.

6.

7.

8.

9.

10.

The amino group and carboxylic group of an amino acid are attached to (1) Amino group to alpha carbon and carboxylic group to beta carbon (2) Carboxylic group to alpha carbon and amino group to beta carbon (3) Both amino and carboxylic groups to alpha carbon (4) Both amino and carboxylic groups to beta carbon. The amino acids that occur in protein are (1) Only essential types (2) Only non essential types (3) Of ten types (4) Of twenty types The ‘R’ group in following amino acid is a methyl group (1) Glycine (2) Serine (3) Tyrosine (4) Alanine Which of the following is not an aromatic amino acid (1) Valine (2) Tyrosine (3) Phenylalanine (4) Tryptophan Mark the incorrect statement (1) Lecithin is a common phospholipid (2) Glycerol is a simple lipid (3) Gingerly oil remains oil in winters also (4) Palmitic acid is an 18 carbon compound Thymidine is a (1) Purine nucleotide (2) Purine nucleoside (3) Pyrimidine nucleotide (4) Pyrimidine nucleoside According to weight percentage the first three elements in human body are (1) C > H > O (2) C > O > N (3) O > N > C (4) O > C > H Guanylic acid is a (1) Nucleoside of purine (2) Nucleoside of pyrimidine (3) Nucleotide of purine (4) Nucleotide of pyrimidine Mark the incorrect statement in the followings (1) The metabolic pathway in which acetic acid is converted into cholesterol is an endothermic one (2) Without metabolism there can not be a living state (3) All living systems are in a state of equilibrium (4) All of these In the composition of cellular mass, arrange the componentsproteins(P), carbohydrates(C), Lipids(L) and Nucleic acids(N) in decreasing order of mass percentage (1) C > N > P > L (2) P > N > C > L (3) P > C > L > N (4) P > N > L > C

11.

12.

13.

14.

15.

16.

17.

18.

19.

20.

Which of the following is a homopolymer (1) Collagen (2) Trypsin (3) Cellulose (4) Chitin Which is the most adundant protein in biosphere (1) Collagen (2) RuBisCO (3) Myosin (4) Haemoglobin Mark the correct statement regarding carbohydrate (1) Inulin is a polymer of fructose (2) The right end in a polysaccharide chain is the reducing end (3) Unlike starch the cellulose does not hold iodine (4) All of these The quaternary structure of protein has minimum (1) One polypeptide chain (2) Two polypeptide chains (3) Three polypeptide chains (4) Four polypeptide chains In a polypeptide the first amino acid is represented as (1) N- terminal on left hand (2) N- terminal on right hand (3) C- terminal on left hand (4) C- terminal on right hand The bond between phosphate and hydroxyl group of sugar in nucleic acid is (1) Glycosidic bond (2) Peptide bond (3) Ester bond (4) None of these One full turn of DNA helical contains (1) 3.4 base pairs (2) 10 base pairs (3) 30 base pairs (4) 20 base pairs Read the following four statements (A to D) and mark the option that has both correct statements A. Blood conc. of glucose in a normal healthy man is 4.5 to 5.0 mM B. In proteins only left handed helices are observed C. The pitch of B- DNA is 3.4 Angstrom D. At each step of ascent the strand of DNA turns 36 degree (1) A, B (2) B, C (3) C, D (4) A, D The 3’ - 5’ phosphodiester linkages inside a polynuleotide chain serve to join [CBSE Final ‘10] (1) One DNA strand with the other DNA strand (2) One nucleoside with another nucleoside (3) One nucleotide with another nucleotide (4) One nitrogenous base with pentose sugar The nucleic acids that behave like enzymes are called (1) Nucleases (2) Abozymes (3) Riboses (4) Ribozymes

BIOMOLECULES : ENZYMES, MINERALS & VITAMINS 21.

22.

23.

24.

25.

A pocket or crevice of an enzyme into which substrate fits, is called (1) Active site (2) Apoenzyme (3) Epitope (4) Coenzyme Mark the correct statement (1) Most of the enzymes get damaged above 40° C (2) The rate of chemical reaction or decreases by half for every 10°C change in either direction (3) The enzyme Carbonic Anhydrase accelerates the rate of hydration of CO2 by about 10 million times (4) All of these Km in enzymatic reaction is (1) The temp. in Kelvin at which reaction velocity is half of the maximum (2) The value at which all enzyme molecules are saturated (3) The conc. of substrate for Vmax. (4) None of these The inhibition of succinic dehydrogenase by malonate is an example of (1) Non-competitive inhibition (2) Competitive inhibition (3) Denaturation of enzyme (4) Allostearic inhibition The class of enzymes that catalyze the removal of a group from a substrate without addition of water, leaving double bonds, is (1) Transferases

(2) Dehydrogenases

(3) Hydrolases

(4) Lyases

405 26.

27.

The prosthetic group of an enzyme is called (1) Coenzyme

(2) Apoenzyme

(3) Cofactor

(4) None of these

Mark the correct statement (1) NAD & NADP are coenzymes that are derivative of vitamin B (2) Catalytic activity is lost when the cofactor is removed from enzyme (3) In carboxypeptidases the metallic ions are of zinc (4) All of these

28.

What is ture regarding peroxidases and catalases (1) Both have coenzymes, derivative of vitamin B (2) Both have haem that becomes associated during catalytic reaction (3) They have no cofactor (4) They have haem as prosthetic group

29.

Three of the following statements about enzymes are correct and one is wrong. Which one is wrong? [CBSE Final ‘10] (1) Enzymes require optimum pH for maximal activity (2) Enzymes are denatured at high temperature but in certain exceptional organisms they are effective even at temperatures 80°-90°C (3) Enzymes are highly specific (4) Most enzymes are proteins but some are lipids

406

BIOLOGY

EXERCISE - 2 | Window to Competitive Exams 1. 2.

3. 4.

5. 6.

7. 8.

9. 10.

11. 12.

13.

Which one is not protein? [RPMT ‘95] (1) Myosin (2) Actin (3) Albumin (4) Haematin Which one of the following is connected by two hydrogen bonds? [BCECE ‘95] (1) Adenine and Guanine (2) Adenine and Thymine (3) Thymine and Guanine (4) Cytosine and Guanine Maximum iron occurs in [RPMT ‘95] (a) Bone cells (2) Protein (c) WBC (4) RBC A nucleoside differs from nucleotide in not having [MP ‘95] (1) Phosphate (2) Sugar (3) Nitrogen base (4) Phosphate and sugar The casein of milk is a [MAHE ‘95] (1) Lipid (2) Carbohydrate (3) Protein (4) Steroid Which of the following sets contains polysaccharides? [CBSE ‘96] (1) Glucose, fructose, lactose (2) Starch, glycogen, cellulose (3) Sucrose, maltose, cellulose (4) Galactose, starch, sucrose Basic unit of protein molecule is [CPMT ‘96] (1) Amino acid (2) Ammonia (3) Ascorbic acid (4) Urea Nucleosides will not yield the following on hydrolysis [DPMT ‘96] (1) Purines (2) Phosphoric acid (3) Pentose sugar (4) Pyrimidines Purine base of RNA is [CBSE ‘96] (1) Guanine (2) Thymine (3) Uracil (4) Cytosine Unique property of ATP is [CPMT ‘96] (1) It resembles RNA (2) It is stored in our body (3) It stores energy in its phosphate bonds (4) none above The constitutent of natural silk is [CBSE ‘96] (1) Nitrogen (2) Phosphorous (3) Calcium (4) Iron One of the following is most diverse molecule of the cell [CBSE ‘96] (1) Water (2) Fat (3) Protein (4) Carbohydrate Amino acids are to proteins as [Punjab ‘96] (1) Pepsin to pepsinogen (2) Sucrose to sucrase (3) Nucleotides to nucieic acid (4) Actin to myosin

14.

15.

16. 17.

18. 19.

20.

21. 22. 23.

24.

25.

26.

Nitorgenous base present in DNA but not in RNA is [RPMT ‘96] (1) Cytosine (2) Uracil (3) Thymine (4) Guanine Pernicious anaemia is caused due the deficiency of vitamin [CPMT ‘88; RPMT ‘96] (1) Thiamine (2) Cobalamine (3) Asorbic acid (4) Calciferol Which one is the correct match ? [DPMT ‘96] (1) Calcium-beriberi (2) Iodine-tooth decay (3) Iron-haemophilia (4) Phosphorus-bone fragility Deficiency of copper causes [MP ‘96] (1) Pellagra (2) Anaemia and damage to CNS (3) Influenza (4) Xerophthalmia A vitamin which is steroid in nature is (1) A (2) B [BCECE ‘96] (3) C (4) D Which ratio is constant for DNA of a particular species? [BCECE ‘97] (1) A + G/T + C (2) A + T/G + C (3) A + C/T + G (4) A + U/C + G Cytidine is [MAHE ‘97] (1) Nucleoside (2) Nucleotide (3) Essential amino acid (4) Nonessential amino acid Two rings are there in [Punjab ‘97] (1) Guanine (2) Thymidine (3) Uracil (4) Cytosine The storage protein is [Punjab ‘97] (1) Tubulin (2) Keratin (3) Starch (4) Glutein The Unit which is formed by sugar and base of β-glycosidic bond is called [MP ‘97] (1) Nucleoside (2) Nucleotide (3) Glycoside (4) Purine In an experiment it was found that adenine constitutes 31% and guanine 19%. The quantity of cytosine in this DNA is likely to be [CET Chd ‘97] (1) 19% (2) 40% (3) 31% (4) 50% Which amino acid has no asymmetrical carbon atom? [AFMC ‘97] (1) Glycine (2) Threonine (3) Proline (4) Histidine One of the following is a polysaccharide [DPMT ‘97] (1) Chitin (2) Glucose (3) Sucrose (4) Maltose

BIOMOLECULES : ENZYMES, MINERALS & VITAMINS 27.

28. 29.

30. 31. 32. 33.

34. 35. 36.

37.

38.

39.

40.

41.

t-RNA is a polymer of [MP ‘97] (1) Deoxyribonucleosides (2) Ribonucleosides (3) Ribonucleotides (4) Deoxyribonucleotides A + G = C + T, then it is [MAHE ‘97] (1) ssRNA (2) dsRNA (3) ssDNA (4) dsDNA Base pairs in DNA are joined by [Punjab ‘97] (1) Disulphide linkage (2) Hydrogen bonding (3) Peptide bonding (4) Glycosidic bonding RNA is [BCECE ‘97] (1) Nucleoside (2) Nucleotide (3) Polynucleotide (4) Protein Number of base pairs are 12 in [MP ‘97] (1) A-DNA (2) B-DNA (3) Z-DNA (4) All above Z-DNA is [Punjab’97] (1) Left handed (2) Right handed (3) Single stranded (4) Double stranded Proteins in silk fibre are [KCET ‘97] (1) Fibrin and serine (2) Chondrin and mucin (3) Fibroin and sericine (4) Collagen and elastin Vitamin B2 is used in coenzyme [AIIMS ‘97] (1) NAD (2) FMN (3) TPP (4) Pyridoxal phosphate Lactose is composed of [CBSE ‘98; RPMT ‘98] (1) Glucose + Glucose (2) Glucose + Fructose (3) Glucose + Galactose (4) Fructose + Galactose Linoleic acid is unsaturated fatty acid and its content is highest in [BHU ‘98] (1) coconut oil (2) sunflower oil (3) groundnut oil (4) cotton oil Burning foot syndrome is due to deficiency of [Punjab ‘98] (1) Vitamin D (2) Vitamin A (3) Vitamin B3 (4) Vitamin B5 Identify the protein that does not contain any metal [CBSE ‘99] (1) Phytochrome (2) Cytochrome (3) Glycoprotein (4) Ferritin Biotin and pantothenic acid belong to the category of [CBSE ‘99] (1) Amino acids (2) Pyrimidines (3) Vitamin B group (4) Steroids Which is mismatched ? [CBSE ‘99] (1) Vitamin K – Beri-beri (2) Vitamin C – Scurvy (3) Vitamin A – Xerophthalmia (4) Vitamin D - Rickets Vitamin E prevents [MAHE ‘99] (1) Formation of vitamin D in skin (2) Secretion of superfluous enzymes (3) Keratinisation of epidermal cells (4) Absorption of harmful enzymes

407 42.

43.

44.

45.

46.

47.

48.

49.

50.

51.

52.

53.

54.

55.

56.

The simplest amino acid is [AFMC 2000] (1) Glycine (2) Proline (3) Leucine (4) Tryptophan Histones are [CPMT 2000] (1) Acidic proteins (2) Basic proteins (3) Mucoproteins (4) Glycoproteins The number of molecule of fatty acids present in one molecule of fat is [BHU 2000] (1) 1 (2) 3 (3) 2 (4) 4 Steroids are important constituent of [MAHE 2000] (1) Cell membrane (2) Sex hormones (3) Enzymes (4) All above The primary structure of protein is made up of [Punjab 2000] (1) Hydrogen bonds (2) Ionic bonds (3) Peptide bonds (4) None above ATP molecule is a [CBSE 2000] (1) Nucleosome (2) Nucleoside (3) Nucleotide (4) Deoxyribose sugar Which of the following amino acids is essential for metabolism? [CBSE 2000] (1) Serine (2) Creatinine (3) Phynylalanine (4) Aspartic acid The acidic character of DNA and RNA is due to [MAHE 2000] (1) Purine (2) Pyrimidine (3) Phosphoric group (4) Sugars Substance forming 80% of cytoplasm is plant cells is [CPMT ‘81, 84; AFMC 2000] (1) Proteins (2) Fat (3) Water (4) Minearls Which amino acids are required for synthesis of haemoglobin? [Punjab 2000] (1) Glu (2) His (3) Lys. (4) All of the above Cholesterol is produced by [MP 2000] (1) liver (2) gastric gland (3) pancreas (4) small intestine Xerophthalmia in children and night blindness in adults is caused by the deficiency of [CPMT ‘89, JK 2000] (1) Vitamin A (2) Vitamin B (3) Vitamin C (4) Vitamin K Loss of appetite, gastrointestinal disorders and muscular weakness are deficiency symptoms of [BVP 2000] (1) Vitamin B (2) Vitamin A (3) Vitamin E (4) Vitamin C Which one of the vitamins can be synthesized by gut bacteria ? [CBSE ‘97; JIPMER 2000] (1) K (2) B1 (3) D (4) C. Which of the following is required for the development of erythrocytes? [AFMC 2000] (1) Vitamin A (2) Vitamin B12 (3) Vitamin E (4) Vitamin K

408 57.

58. 59.

60.

61.

62. 63.

64. 65.

66. 67.

68. 69. 70.

BIOLOGY Which vitamin is required for the synthesis of rhodopsin? [MP 2000] (1) C (2) B2 (3) D (4) A Which is not a micronutrient? [Haryana 2000] (1) Zn (2) Ca (3) Cu (4) Mo Which one of the following glycosidic linkage is found in maltose? [Kerala ‘01] (1) β 1 4 (2) α 1, 4 (3) β 1, 6 (d) α 1, 6 Which statement is correct for biomolecules? [RPMT ‘01] (1) DNA is a polymer of ribonucleotides (2) All carbohydrates breakdown into glucose (3) Sequence of amino acids determines primary protein structure (4) RNA is single stranded and contains different purine bases other than in DNA Which of the following is a basic amino acid? [DPMT ‘01] (1) Leucine (2) Lysine (3) Methionine (4) Aspartic acid The length of one full turn of DNA is [Kerala ‘01] (1) 3.4 Å (2) 34.0 Å (3) 20.0 Å (4) 2.0 Å Fehling’s solution is used for detection of [CBSE ‘01] (1) Glucose (2) Starch (3) All types of carbohydrates (4) Fats Example of hexose sugar is [BCECE ‘01] (1) mannose (2) galactose (3) arabinose (4) both (1) and (2) Vitamin K is required for [CBSE ‘93; CET Chd 2000; BHU ‘01] (1) Change of prothrombin to thrombin (2) Synthesis of prothrombin (3) Change of fibrinogen to fibrin (4) Formatioin of thromboplastin Whch is not available from plants [DPMT ‘01] (1) Riboflavin (2) Cyanocobalamine (3) Thiamine (4) Vitamin C Which one is correctly matched [CBSE ‘01] (1) Vitamin E - Tocopherol (2) Vitamin D – Riboflavin (3) Vitamin B – Calciferol (4) Vitamin A – Thiamine Which of the following is a trace element? [MP ‘01] (1) S (2) Fe (3) Cu (4) Mg The most basic amino acid is [AIIMS ‘02] (1) Arginine (2) Histidine (3) Glycine (4) Glutamine Unsaturated fatty acids have [Kerala ‘02] (1) Palmitic acid (2) Oleic acid (3) High melting point (4) One or more double bonds

71. 72.

73.

74.

75.

76.

77.

78. 79. 80.

81. 82.

83. 84.

85.

Which of the following is conjugated protein?[AMU ‘02] (1) Keratin (2) Albumin (3) Collagen (4) Haemoglobin If all the peptide bonds of a protein are broken down, then what would remain? [RPMT ‘02] (1) Amino acids (2) Peptides (3) Polypeptides (4) Oligopeptides A peptide chain assumes secondary structure through the formation of [Orissa ‘02] (1) interchain ionic bond (2) intrachain hydrogen bond (3) peptide bond (4) intrachain disulphide linkage Which of the following sugar is not found in plants? [Orissa ‘02] (1) sucrose (2) glucose (3) lactose (4) fructose Osmotically inactive chief stored material in animal body is [BHU ‘02] (1) lipid (2) protein (3) glycogen (4) phosphogen Non-reducing sugars have [Punjab ‘02] (1) Free CHO group and bound CO group (2) Free CO group and bound CHO group (3) Both CO and CHO free groups (4) Neither free CO nor free CHO group Which of the following is not an amino acid? [AMU ‘02] (1) Arginine (2) Lysine (3) Thymine (4) Tryptophan Which of these amino acid is hydrophilic? [AIIMS ‘02] (1) Histidine (2) Phenylalanine (3) Glycine (4) Lysine Monosaccharides found in nucleolus is [CMCL ‘02] (1) Hexose (2) Pentose (3) Tetrose (4) Erythrose The proteins associated with nucleic acids are [Kerala ‘02] (1) Scleroproteins (2) Albumins (3) Histones (4) Globulins Uridine monophosphate is found in [Kerala ‘02] (1) Centrosome (2) Lysomome (3) RNA (4) DNA Nucleosides are [BHU 2000; BVP ‘02] (1) Purine and pyrimidines only (2) Purine/pyrimidine and sugar (3) Purine/Pyrimidine, sugar and phosphate (4) Sugar and Phosphate. Which of the following is a reducing sugar? [CBSE ‘02] (1) Glucinol (2) Galactose (3) β galactosidase (4) None of these Distance between 200 nitrogen base pairs in DNA is [MAHE ‘02] (1) 68mm (2) 680 Å (3) 68 nm (4) 68000 Å The length of DNA segment is 340 Å. How many base pairs are present in it? [Wardha ‘02] (1) 100 (2) 34 (3) 10 (4) 340

BIOMOLECULES : ENZYMES, MINERALS & VITAMINS 86.

87.

88.

89. 90.

91.

92.

93. 94.

95. 96. 97.

98.

99.

In a DNA molecule thymine is 20% then guanine is? [CBSE ‘02] (1) 20% (2) 30% (3) 60% (4) 40% According to Watson and Crick how many base pairs are there in each turn of the helix of DNA? [Haryana ‘02] (1) 10 (2) 11 (3) 12 (4) 13 Chargaff’s rule is applicable to [KCET ‘02] (1) Single stranded DNA (2) Double stranded DNA (3) Single stranded RNA (4) Single stranded DNA and RNA Distance between two DNA strands is [CMCL ‘02] (1) 20 Å (2) 34 Å (3) 3.4 Å (4) 2 Å In ATP, the high energy bond is the one which links (1) Adenine with phosphate [KCET ‘02] (2) Adenine with ribose (3) Ribose with phosphate (4) Phosphate to phosphate Cellulose is [Jharkhand ‘02] (1) Heptose polysaccharide (2) Pentosan polysaccharide (3) Hetero polysaccharide (4) Hexose polysaccharide Which particular fatty acid is not synthesized in human body [AMU ‘02] (1) Stearic acid (2) Linoleic acid (3) Cholesterol (4) None of these Purines in RNA are [Jharkhand ‘02] (1) uracil and cytosine (2) thymine and cytosine (3) thymine and uracil (4) adenine and guanine Physiologically vitamin E is known to be (1) anti-inflammatory [IAS ‘02] (2) a powerful antioxidant (3) an important co-enzyme (4) anti-hypertensive factor Antisterility vitamin is [MP ‘02] (1) Vit. E (2) Vit. D (3) Vit. A (4) Vit. B12 Which one does not belong to vit. B group [MP ‘02] (1) Riboflavin (2) Nicotinic acid (3) Tocopherol (4) Cyanocobalamine Which one is essential for DNA replication or cell division [MP ‘02] (1) Vit. E (2) Folic acid (3) Vit. K (4) Vit. D Excessive bleeding from an injury is due to deficiency of [CBSE ‘02] (1) Vitamin A (2) Vitamin B (3) Vitamin K (4) Vitamin E Match the pair in which deficiency results in swollen lips, thick pigmented skin of hands and legs and irritability [BHU ‘02] (1) Iodine – goitre (2) Thiamine – beri beri (3) Niacin – Pellagra (4) Protein – Kwashiorkar.

409 100. Vitamin nicotinamide can be synthesized in our body from [AIIMS ‘02] (1) Tyrosine (2) Tryptophan (3) Valine (4) Phenylalanine 101. Which one is rich in Magnesium [JIPMER ‘02] (1) Milk (2) Meat (3) Soyabean (4) Egg. 102. Osteomalacia in adults is caused due to the deficiency of [Kerala ‘02] (1) Vitamin D (2) Vitamin C (3) Vitamin A (4) Vitamin K 103. Riboflavin deficiency causes which disease? [PCS ‘02] (1) Scurvy (2) pellagra (3) Beriberi (4) Cheilosis 104. Which of the following does not yield glucose on hydrolysis? [AMU ‘03] (1) starch (2) Maltose (3) cellulose (4) hemicellulose 105. Starch is made up of [Jharkhand ‘03] (1) Fructose (2) cellobiosc (3) amylopectin (4) amino acids 106. During protein denaturation which of the following is disrupted? [DPMT ‘03] (1) Secondary structure (2) 3D structure (3) Peptic bond (4) AA sequence 107. The tertiary structure of the proteins containing the amino acid cysteine is achieved through [Kerala ‘03] (1) hydrogen bonds (2) disulphide bonds (3) van der Waals’ force (4) ionic bond 108. Which of the following statements is wrong? [Jharkhand ‘03] (1) Sucrose is a disaccharide (2) Cellulose is a polysaccharide (3) Glycine is a sulphur containing amino acid (4) Uracil is a porimidine 109. Which one of the following is not a fibrillar protein? [Kerala ‘03] (1) Elastin (2) Collagen (3) Myosin (4) Albumin 110. Scleroproteins are [Kerala ‘03] (1) Keratin (2) Collagen (3) Both (1) and (2) (4) Glycoproteins 111. A doctor advises a patient to include yellow fruits, carrots and butter in his diet. What deficiency disease to you think the patient is suffering from? (1) Night blindness [JK ‘03] (2) Colour blindness (3) Kwashiorkor disease (4) Marasmus disease 112. The set of three elements included fully in mcronutrients is [Orissa ‘03] (1) Na, Cu, Mg (2) Fe, Zn, Cu (3) Fe, K, Ca (4) Mn, Ni, P 113. Major population of India is suffering from anaemia due to the deficiency of [CMC Vellore ‘03] (1) Mg (2) Fe (iron) (3) Vitamin B1 (4) Vitamin B12

410

BIOLOGY

114. Which one is incorrectly matched [CBSE ‘03] (1) Vit C – scurvy (2) Vit. B2 - Pellagra (3) Vit. B12 – Pernicious anaemia (4) Vit. B6 – Loss of apotite 115. The helical structure of protein is stabilized by [CBSE ‘04] (1) Ester (2) Peptide bonds (3) Disulphide bonds (4) hydrogen bonds 116. The richest sources of vitamin B12 are [CBSE ‘04] (1) Carrot and chicken’s breast (2) Goat’s liver and Spirulina (3) Chocolate and green gram (4) Rice and hen’s egg 117. In the percentage of adenine in a double stranded DNA molecule is 20, the percentage of guanine is [AIIMS ‘83; Haryana ‘05] (1) 80% (2) 20% (3) 30% (4) 40% 118. Cellulose is a [CPMT ‘91; MAHE ‘05] (1) Disaccharide (2) Pentosan Polysaccharide (3) Homoglycan pentosan (4) Homoglycan hexosan 119. Nucleotides are building blocks of nucleic acids. Each nucleotide is a composite molecule formed by: [CBSE ‘05] (1) base-sugar-phosphate (2) base-sugar-OH (3) (base-sugar-phosphate)n (4) sugar-phosphate 120. Which of the following is found in DNA ? [CPMT ‘05] (1) adenine (2) cytosine (3) uracil (4) thymine 121. The alcohol obtained on fat metabolism is [BCECE ‘05] (1) methanol (2) ethanol (3) glycerol (4) all of these 122. Which is a reducing sugar [BCECE ‘05] (1) cellulose (2) starch (3) sucrose (4) maltose 123. The following diagrams represent the nitrogenous bases of nucleic acid molecules. Identify the correct combination [Kerala ‘05] NH2 NH O O 2 O O C N C CH C C N C CH33 C C N C CH C HN HN N C CH HN HN CH CH HC C C C HC CH CH C C C CH CH NH N O O NH NH N NH O O NH NH C B A C B A O O C C

HN HN22

HN HN

C C

C C

C C

N N CH CH NH NH

N N D D

NH2 NH 2 C C

O O

125.

126.

127.

128.

129.

130.

131.

132.

133.

134.

N N

CH CH

C C

CH CH NH NH E E

124.

135.

(1) A - uracil, B - adenine, C-thymine, D-guanine E- cytosine (2) A - uracil, B-guanine, C-cytosine, D-adenine, E-thymine (3) A - uracil, B - guanine, C-thymine, D-adenine, E-cytosine (4) A-thymine, B-guanine, C-uracil, D-adenine, E - cytosine. Maltose consiss of which one of the following? [MAHE ‘05] (1) β- glucose and β -galactose (2) α- glucose and α- fructose (3) α-sucrose and β- glucose (4) glucose and glucose Which is protein in nature? [Haryana ‘05] (1) polyethylene (2) silk and wool (3) cellulose (4) teryliene The type of linkage present in carbohydrates is [CPMT ‘05] (1) peptide (2) glycosidic (3) amide (4) phosphate bonds Which is soluble RNA? [CPMT ‘05] (1) hnRNA (2) rRNA (3) mRNA (4) tRNA t Low calorie and low cholesterol is found in [Orissa ‘05] (1) soyabean oil (2) pea nut oil (3) sesam oil (4) safflower oil Which is false? [Haryana ‘05] (1) A/T is equal to one (2) A + G = C + T (3) A + T = C + G (4) C/G is equal to one How many pair of nucleotides are present in one helix of β- DNA? [Haryana ‘05] (1) 10 (2) 12 (3) 5 (4) 6 In a DNA molecule, nucleosides contain, [Manipur ‘05] (1) nitrogenous base + pentose sugar (2) nitrogenous base + pentose sugar + phosphoric acid (3) nitogenous base only (4) pentose sugar + phosphoric acid In RNA, the thymine is replaced by [JK ‘05] (1) guanine (2) adenine (3) uracil (4) cytosine. Monomer of nucleic acid is [BCECE ‘05] (1) nitrogen bases (2) nucleotide (3) nucleoside (4) sugar The protein present in wheat grain is [Orissa ‘05] (1) glutenin (2) glycogen (3) zymase (4) albumin Which of the follwing amino acids is not optically active? [BHU ‘05] (1) glycine (2) valine (3) leucine (4) isoleucine.

BIOMOLECULES : ENZYMES, MINERALS & VITAMINS

142.

143. 144.

145.

Velocity (v)

136. Which of the following statements regarding enzyme inhibition is correct? [CBSE’05] (1) Competitive inhibition is seen when a substrate competes with an enzyme for binding to an inhibitor protein. (2) Competitive inhibition is seen when the substrate and the inhibitor compete for the active site on the enzyme. (3) Non-competitive inhibition of an enzyme can be overcome by adding large amount of substrate. (4) Non-competitive inhibitors often bind to the enzyme irreversibly. 137. The catalytic efficiency of two different enzymes can be compared by the [CBSE ‘05] (1) formation of the product (2) pH optimum value (3) Km value (4) molecular size of the enzyme 138. Enzymes, vitamins and hormones can be classified into a single category of biological chemicals, because all of these [CBSE ‘05] (1) help in regulating metabolism (2) are exclusively synthesized in the body of a living organism as at present (3) are conjugated proteins (4) enhance oxidative metabolism 139. The given graph shows the effect of substrate concentration on the rate of reaction of the enzyme green -gram -phosphatase. What does the graph indicate ? [AIIMS ‘05]

411

146. O Substrate Concentration (s)

(1) The rate of enzyme reaction is direcly proportional to the substrate concentration (2) Presence of an enzyme inhibitor in the reaction mixture (3) Formation of an enzyme-substrate complex (4) at higher substrate-concentration the pH increases. 140. Vitamin needed for blood coagulation is [BHU ‘86; JIPMER ‘86; MP ‘94, ‘99; Haryana ‘05] (1) E (2) D (3) K (4) C 141. Which group of three of the following five statements (a-e) contain is all three correct statements regarding beri-beri? [CBSE ‘05] (a) a crippling disease prevalant among the native population of sub-Saharan Africa; (b) a deficiency disease caused by lack of thiamine (vitamin B1) (c) a nutritional disorder in infants and young children when the diet is persistently deficient in essential protein;

147.

148.

149.

150.

(d) occurs in those countries where the staple diet is polished rice; (e) the symptoms are pain from neuritis, paralysis, muscle wasting, progressive oedema, mental deterioration and finally heart failure; (1) b, d and e (2) a, b and d (3) a, c and e (4) b, c and e Which of the following vitamins is water soluble as well as anti-oxidant? [BHU ‘05] (1) vit B1 (2) vit A (3) vit D (4) vit C Fat soluble vitamin is [BCECE ‘05] (1) A (2) B (3) C (4) B12 Which pair is essential for the growth of fish in water? [BHU ‘05] (1) calcium and phosphorus (2) phosphates and carbonates (3) sulphate and carbonates (4) nitrates and sulphates Match the following nutritional vitamin deficiencies in column I with the causes/deficiencies in column II and choose the correct option from the answer key. [Kerala ‘05] Column I Column II A. Kwashiorkar p. Iron B. General anaemia q. Menadione C. Dermatitis r. Protein D. Marasmus s. Pyridoxine E. Bleeding t. Biotin (1) A = p, B = t, C = q, D = r, E =s (2) A = t, B = q, C = r, D = s, E = p (3) A = t, B = r, C = s, D = p, E = q (4) A = r, B = s, C = p, D = t, E = q The deficiency of which vitamin is known to cause abortion in early pregnancy of rat? [EAMCET ‘05] (1) Retinol (2) Calciferol (3) Tocopherol (4) Napthoquinone How Many of the twenty two amino acids are essential amino acids for children? [Kerala’06] (1) 6 (2) 8 (3) 10 (4) 11 Name the elements which occur in nucleic acid macromolecule [Kerala’06] (1) C, H, O, N, S (2) C, H, O, N, P (3) C, O, P, S (4) C, O, N, S The similarity between RNA and DNA is [CBSE 2000; KCET’06] (1) Both are made up of same pyrimidines (2) Both have same thymidine bases (3) Both have same sugars (4) Both are nucleotide polymers One turn of the helix in a B-form DNA is approximately [CBSE ‘06] (1) 0.34 nm (2) 3.4 nm (3) 2 nm (4) 20 nm

412 151. Antiparallel strands of a DNA molecule means that [CBSE ‘06] (1) the phosphate groups of two DNA strands, at their ends. share the same position (2) the phosphate groups at the start of two DNA strands are in opposite position (pole) (3) one strand turns clockwise (4) one strand turns anti-clockwise 152. Paraffin wax is [BHU’06] (1) ester (2) acid (3) monohydric alcohol (4) cholesterol 153. Which is the most abundant protein on earth? [AMU’06] (1) lignin (2) Rubisco R (3) cellulose (4) pectin 154. Phosphodiester bond is present in [AMU’06] (1) ATP (2) ADP (3) cAMP (4) none of these 155. A sample of DNA is found to have the base composition (mole ratio) of adenine = 40, T = 22, G = 21 and cyto = 17. This [HPMT’06] (1) DNA is circular duplex (2) DNA is linear duplex (3) DNA is single stranded (4) DNA has high melting point 156. In maltose the glucose residues are linked by [HPMT’06] (1) β 1 - 4 linkage (2) α 1 - 4 linkage (3) α 1 - 6 linkage (4) α 1 - 2 linkage 157. The rule that in a DNA the amount of adenine equals to that of the thymine and that of guanine equals to that of cytosine, is known as [JK’06] (1) Allen’s rule (2) Jordan’s role (3) Chargaff’s rule (4) Stahl’s rule 158. The bonds associated with the secondary structure of protein molecules are [JK’06] (1) peptide bonds (2) phosphodiester bonds (3) hydrogen bonds (4) energy rich bonds 159. Which of the following forms the backbone of a fat molecule? [JK’06] (1) glycerol (2) glutamic acid (3) galactose (4) guanine 160. An example of ketose sugar is [JK’06] (1) ribose (2) xylose (3) Erythrose (4) fructose 161. The scientist who first established the protein nature of the biocatalysts is [JK’06] (1) Pasteur (2) Summer (3) Haldane (4) Robertson 162. Common immediate source of energy is [Orissa’06] (1) AMP (2) ATP (3) ADP (4) GTP 163. Match the items in column I with items in column II and choose the correct answer [Kerala’06] Column I Column II a. triglyceride 1. animal hormones b. membrane lipid 2. feathers and leaves c. steroid 3. phospholipids d. wax 4. fat stored in form of droplets

BIOLOGY

164.

165.

166.

167.

168. 169.

170.

171.

172.

173.

(1) a–4, b–3, c–1, d–2 (2) a–2, b–3, c–4, d–1 (3) a–3, b–4, c–1, d–2 (4) a–4, b–1, c–2, d–3 An organic substance bound to an enzyme and essential for its activity is called [CBSE ‘06] (1) Holoenzyme (2) Apoenzyme (3) Isoenzyme (4) Coenzyme Allosteric modulation is due to the inhibition action of enzyme by [Kerala’06] (1) competitive inhibition (2) substrate concentration (3) products of reaction (4) enzyme concentration Km of enzyme can be expressed as [HPMT’06] (1) the substrate concentration at 1/2 of maximum velocity of enzyme action (2) the substrate concentration at maximum velocity of enzyme action (3) half of maximum velocity of enzyme at unit substrate concentration at infinite velocity of enzyme action (4) substrate concentration at infinite velocity of enzyme action In an enzyme catalysed reaction the energy of activation of reactant is [HPMT’06] (1) lowered (2) increased (3) remains unchanged (4) equal to free energy Dentine is secreted by [Orissa’06] (1) odontoblast (2) ameloblast (3) osteoblast (4) chondroblast Pellagra is caused due to the deficiency of [CBSE ‘96; CPMT ‘96; MP ‘98; AMU ‘06] (1) Ascorbic Acid (2) Nicotinic acid (3) Pantothenic acid (4) Folic acid Nyctalopia is caused by deficiency of vitamin [BHU ‘82; CPMT ‘88; HPMT ‘06] (1) E (2) A (3) D (4) B12 Which one is correctly matched? [Kerala’06] (1) vitamin E - thiamine (2) vitamin B1 -tocopherol (3) vitamin A - calciferol (4) vitamin B12 - cyanocobalamine Examination of blood of a person suspected of having anemia, shows large, immature, nucleated erythrocytes without hemoglobin. Suppelementing his diet with which of the following, is likely to alleviate his symptoms? [CBSE ‘06] (1) Folic acid and cobalamine (2) Riboflavin (3) Iron compounds (4) Thiamine Vitamin -D is synthesised in skin by the action of sunlight on [BHU’06] (1) cholesterol (2) 7-hydroxy cholesterol (3) cephalin cholesterol (4) all of these

BIOMOLECULES : ENZYMES, MINERALS & VITAMINS [AMU’06] 174. Yeast and algae are main sources of (1) vitamin B complex (2) vitamin C (3) minerals (4) vitamin K 175. The two polynucleotide chains in DNA are: [CBSE’07] (1) semiconservative (2) parallel (3) discontinuous (4) antiparallel 176. Which one of the following vitamin is water-soluble? [CBSE’07] (1) Vitamin A (2) Vitamin B (3) Vitamin E (4) Vitamin K

413 177. Which one of the following is a fat-soluble vitamin and its related deficiency disease? (1) Calciferol Pellagra [CBSE’07] (2) Ascorbic acid Scurvy (3) Retinol Xerophthalmia (4) Cobalamine Beri-beri 178. Which one of the following pairs of nitrogenous bases of nucleic acids, is wrongly matched with the category mentioned against it ? [CBSE’08] (1) Adenine, Thymine - - Purines (2) Thymine, Uracil - - pyrimidines (3) Uracil, Cytosine - - pyrimidines (4) Guanine, Adenine - - purines

179. The figure given below shows the conversion of a substrate into product by an enzyme. In which one of the four options (1-4) the components of reaction labelled as A, B, C and D are identified correctly? [CBSE’ 10, Final] A (1) Potential energy (2) Transition state (3) Potential energy (4) Activation energy with enzymes

B Transition state Potential energy Transition state Transition state

C Activation energy with enzymes Activation energy without enzymes Activation energy with enzymes Activation energy without enzymes

180. Three of the following statements about enzymes are correct and one is wrong. Which one is wrong? [CBSE’ 10] (1) Enzymes require optimum pH for maximal activity (2) Enzymes are denatured at high temperature but in certain exceptional organisms they are effective even at temperatures 80°-90°C (3) Enzymes are highly specific (4) Most enzymes are proteins but some are lipids 181. “All enzymes are proteins.” This statement is now modified because an apparent exception to this biological truth is [DPMT’ 10] (1) Arylsulfatase (2) Dehydrogenase (3) Ribozyme (4) Nitroreductase 182. The curve given below show enzymatic activity with relation to three conditions (pH, temperature and substrate concentration) [CBSE’ 11] What do the two axises (x and y) represent?

Y-axis

X-axis

(1) (2) (3) (4)

x-axis Enzymatic Enzymatic Temperature Substrate

y-axis activity Temperature activity pH Enzyme Activity Enzymatic Activity

D Activation energy without enzymes Activation energy with enzymes Activation energy without enzymes Potential energy

A C B

D substrate (s) Product (P) Progress of reaction

183. In the DNA molecule : [CBSE’08] (1) there are two starands which run antiparallel-one in 5’ → 3’ direction and other in 3’ → 5’ (2) the total amount of purine nucleotides and pyrimidine nucleotides is not always equal (3) there are two strands which run parallel in the 5’ → 3’ direction. (4) the proportion of Adenine in relation to thymine varies with the organism. 184. In DNA, the complimentary bases are [CBSE’08] (1) Uracil and adenine; cytosine and guanine (2) Adenine and thymine; guanine and cytosine (3) Adenine and thymine; guanine and uracil (4) Adenine and guanine; thymine and cytosine 185. A competitive inhibitor of succinic dehydrogenase is : (1) Malate (2) Malonate [CBSE ‘08] (3) Oxaloacetate (4) α - ketoglutarate 186. A particular enzyme molecule interacts with a specific substrate molecule is explained by [DPMT’ 10] (1) Enzyme-substrate concept (2) Activation energy concept (3) Destroyed and re-synthesized concept (4) Lock and key concept 187. Which of the following vitamins has some physiological effects similar to those of parathormone? [DPMT’ 10, 11] (1) Vitamin A (2) Vitamin D (3) Vitamin C (4) Vitamin B

414 188. Osteomalacia is a deficiency disease of [WB- JEE’ 11] (1) Infants due to protein energy malnutrition (2) Adults due of protein energy malnutrition (3) Adults due to Vitamin D deficiency (4) Infants due to Parathormone deficiency 189. Transition state structure of the substrate formed during an enzymatic reaction is [AIPMT (NEET)’13] (1) Transient but stable (2) Permanent but unstable (3) Transient and unstable (4) Permanent and stable 190. A phosphoglyceride is always made up of [AIPMT (NEET)’13] (1) Only a saturated fatty acid esterified to a glycerol molecule to which a phosphate group is also attached (2) Only an unsaturated fatty acid esterified to a glycerol molecule to which a phosphate group is also attached (3) A saturated or unsaturated fatty acid esterified to a glycerol molecule to which a phosphate group is also attached (4) A saturated or unsaturated fatty acid esterified to a phosphate group which is also attached to a glycerol molecule 191. The macromolecule chitin is [AIPMT (NEET)’13] (1) Nitrogen containing polysaccharide (2) Phosphorus containing polysaccharide (3) Sulphur containing polysaccharide (4) Simple polysaccharide 192. The essential chemical components of many coenzymes are [AIPMT (NEET)’13] (1) Proteins (2) Nucleic acids (3) Carbohydrate (4) Vitamins 193. The amino acid alanine is [AMU’13] (1) Monoamino monocarboxylic amino acid (2) Sulphur containing amino acid (3) Monoaminodicarboxylic amino acid (4) Basic amino acid 194. Which of the following statement is false with respect to prosthetic groups? They are [AMU’13] (1) Proteins (2) Non- proteins (3) Tightly bound to enzymes (4) Metal compounds 195. Which of the following statement is not correct? [AMU’13] (1) Starch is a polymer of α- glucose (2) Starch is made up of amylose and amylopectin (3) Amylose is linear structure consisting of several glucose residues joined 1, 4- glycosidic linkages (4) Amylopectin is a straight chain with several glucose residues joined only 1, 4- glycosidic linkages 196. Individual subunits of polysaccharides are linked by: [AMU’13] (1) Glycosidic bonds (2) Phosphodiester bonds (3) Peptide bonds (4) Hydrogen bonds

BIOLOGY 197. Sucrose is made up of: [AMU’13] (1) Glucose- galactose (2) Glucose- fructose (3) Glucose- glucose (4) Fructose- fructose 198. Which of the following is a protein deficiency disease? [AMU’13] (1) Osteomalacia (2) Kwashiorkor (3) Pellagra (4) Rickets 199. Which structural level enables the proteins to function as enzymes? [AMU’14] (1) Primary (2) Secondary (3) Tertiary (4) Quaternary 200. An organic non- protein cofactor which is easily separable from the apoenzyme is called: [AMU’14] (1) Prosthetic group (2) Coenzyme (3) Alloenzyme (4) All the above 201. Which biomolecules other than proteins can be catabolized by human and apes for the production of uric acid? [AMU’14] (1) Carbohydrates (2) Lipids (3) Nucleic acids (4) Vitamins 202. The substrate of an enzyme is: [AMU’14] (1) The reactant of the reaction catalyzed by the enzyme (2) Competitive inhibitor of the enzyme (3) Uncompetitive inhibitor of the enzyme (4) Prosthetic group of the enzyme 203. Which of the following statements regarding enzymes is not true? [AMU’14] (1) Enzymes lower the activation energy of a reaction (2) Enzymes speed up the attainment of equilibrium of the reaction (3) Enzyme change the value of equilibrium constant of the reaction (4) All the above 204. Human haemoglobin contains: [AMU’14] (1) Secondary structure (2) Tertiary structure (3) Quaternary structure (4) All the above 205. Fish proteins are considered nutritionally superior to the most vegetable proteins because they are rich in: [AMU’14] (1) All the 20 amino acids (2) Essential amino acids (3) Peptide bonds (4) Polypeptides 206. Select the option which is not correct with respect to enzyme action: [AIPMT’14] (1) Substrate binds with enzyme at its active site (2) Addition of lot of succinate does not reverse the inhibition of succinic dehydrogenase by malonate (3) A non- competitive inhibitor binds the enzyme at a site distinct from that which binds the substrate (4) Malonate is a competitive inhibitor of succinic dehydrogenase

BIOMOLECULES : ENZYMES, MINERALS & VITAMINS 207. Which one of the following statements is incorrect? [AIPMT’15] (1) A competitive inhibitor reacts reversibly with the enzyme to form an enzyme- inhibitor complex (2) In competitive inhibition, the inhibitor molecule is not chemically changed by the enzyme (3) The competitive inhibitor does not affect the rate of breakdown of the enzyme – substrate complex (4) The presence of the competitive inhibitor decreases the Km of the enzyme for the substrate 208. In sea urchin DNA, which is double stranded, 17% of the bases were shown to be cytosine. The percentage of the other three bases expected to be present in this DNA are: [AIPMT’15] (1) G 34%, A 24.5 %, T 24.5 % (2) G 17 %, A 16.5 %, T 32.5 % (3) G 34%, A 33 %, T 33 % (4) G 8.5 %, A 50 %, T 24.5 % 209. The chitinous exoskeleton of arthropods is formed by the polymerization of [RE-TEST AIPMT’15] (1) D- glucosamine (2) N- acetyl glucosamine (3) Lipoglycans (4) Keratin sulphate and chondroitin sulphate 210. Which of the following biomolecules does have phosphodiester bond? [RE-TEST AIPMT’15] (1) Monosaccharides in polysaccharide (2) Amino acids in polypeptide (3) Nucleotides in nucleic acid (4) Fatty acids in a diglyceride 211. The amino acid, Phenyl alanine is poorly soluble in water, because its side chain or R group is: [UPCPMT’15] (1) Hydrophilic (2) Heterocyclic chain (3) Aromatic and Non- polar (4) Aromatic and polar 212. Number of nucleotide bases in a spiral of ds DNA is: [UPCPMT’15] (1) 5 (2) 10 (3) 20 (4) 40

415 213. Which one of the following is not protein? [UPCPMT’15] (1) Actin (2) Albumen (3) Haematin (4) Myosin 214. Adjacent nucleotides are joined by a: [AMU’15] (1) Covalent bond (2) Phosphodiester bond (3) Ionic bond (4) Peptide bond 215. Cellulose is the polymer of: [AMU’15] (1) α-D Glucose (2) β-D Glucose (3) α-D Fructose (4) β-D Fructose 216. Which of the following is a disaccharide? [AMU’15] (1) Glucose (2) Lactose (3) Starch (4) Galactose 217. Which of the following cannot be attributed to glycogen? [AMU’15] (1) Homopolysaccharide (2) Heteropolysaccharide (3) Branched chain molecule (4) Stored in liver and muscle 218. The given organic compound is a diagrammatic representation of: [KERALA’15]

(1) Lecithin (2) Adenosine (3) Adenylic acid (4) Uridine 219. Which of the following statements about the structure of proteins is true? [KERALA’15] (1) The sequences of amino acids in a protein represent the secondary structure (2) The helices of proteins are always left handed (3) The adult human haemoglobin consists of two subunits (4) Proteins are heteropolymers containing strings of amino acids 220. The moiety present at the 5’ end of ribose sugar in a polynucleotide is: [KERALA’15] (1) OH (2) CH2 (3) Phosphate (4) Adenine

416

BIOLOGY

EXERCISE - 3 | Test Yourself 1.

2.

3.

4.

5.

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The most abundant organic compound in the biosphere is (1) Protein (2) Nucleic acid (3) Water (4) Cellulose Grape sugar is (1) Sucrose (2) Glucose (3) Fructose (4) None of these Starch, cellulose and glycogen are all carbohydrates. The property which they all share is (1) Branched structure (2) α – 1,4 linkage (3) Polymers of glucose (4) Originate from plant sources Mark the odd one out (1) Ribose (2) Mannose (3) Galactose (4) Raffinose Which of the following in not an aromatic amino acid (1) Thereonine (2) Tyrosine (3) Tryptophan (4) Phenylalanine Framework elements of protoplasm are : (1) C H N (2) H N O (3) O C N (4) C H O In human body how much % part of total water is present as intracellular fluid (1) 55 % (2) 35% (3) 80 % (4) 75 % Which of the following is formed by deamination of Adenine (1) Xanthine (2) Hypoxanthine (3) Uracil (4) Guanine A lipid having tetra cyclic structure is (1) Wax (2) Sterol (3) Neutral fat (4) Phospholipid Which of the following is an antifertility steroid? (1) Estradiol (2) Diosgenin (3) Progesterone (4) Stilbesterol Which of the following is an indispensable amino acid, and contains sulphur (1) Cysteine (2) Methionine (3) Phenylalanine (4) Lysine Which of the following is a polysaccharide but is not the polymer of glucose. (1) Starch (2) Keratin (3) Chitin (4) Cellulose

13.

14.

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22.

Basic amino acids have more amino groups than carboxylic groups. Which of the following set has both basic amino acids? (1) Glutamic acid and Glycine (2) Histidine and Lysine (3) Arginine and Valine (4) None of these Which of the following is a nuclear stain (1) Neutral red (2) Janus green (3) Sudan red (4) Acetocarmine β-oxidation of a 18 –C fatty adid yields (1) 38 ATP (2) 27 ATP (3) 33 ATP (4) More than 40 ATP The high energy bonds of ATP are present between (1) C – N (2) C – C (3) O – P (4) C – O In structure the keratin of mammalian hairs is (1) α−helical like silk fibroin (2) β−pleated like silk (3) α−helical unlike silk fibroin (4) β−pleated unlike silk Which of the following type of bond gives protein a secondary structure? (1) Peptide bond (2) Disulphide bond (3) Hydrogen bond (4) Hydrophobic and Vaander Val forces Which of the following sugar exists in both open chain and ring form (1) Pentose only (2) Pentose and Hexose only (3) All monomers having 3 to 7 carbon atoms (4) Hexose only Palmitic acid and stearic acid are (1) Saturated fatty acids so essential for the body (2) Saturated F. acids so non-essential for the body (3) Unsaturated F acids so essential for the body (4) Unsaturated F acids so non-essential for the body Which of the following is a standard but non-essential amino acid? (1) Methionine (2) Tyrosine (3) Ornithine (4) Isoleucine 5-bromouracil base is analogous to (1) Adenine (2) Gaunine (3) Thymine (4) Cytosine

BIOMOLECULES : ENZYMES, MINERALS & VITAMINS 23.

24.

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Which of the following classes of biomolecules are known to have catalytic properties : (1) Protein and lipid (2) Protein and RNA (3) Protein and carbohydrate (4) Carbohydrate and lipid Feulgen reaction is based on whch unique component of DNA (1) Thymine (2) Deoxyribose (3) Adenine (4) H3PO4 Which of the following statement is true? (1) Cellulose and Glycogen both have β−glucose (2) Glycogen has α−glucose and Cellulose has β−glucose (3) Glycogen and Cellulose both have α−glucose (4) Cellulose has α - glucose and Glycogen has β−glucose Iron combines with Porphyrin to form Haem pigment. Such Haem molecule is present in haemoglobin and (1) Cytochrome (2) Catalase (3) Myoglobin (4) All of these Mark the correct combination of organic compound and its test (1) Proteins – Biuret test and Millon’s test (2) Lipid- Benedict test and Fehling test (3) Sugars – Sudan III test (4) All of these Keratin and Collagen are (1) Globular proteins (2) Conjugated proteins (3) Scleroprotein (4) Not Proteins Fructose is a (1) Reducing sugar like maltose (2) Non reducing sugar like glucose (3) Reducing sugar like sucrose (4) Non-reducing sugar like lactose Which mineral element is most abundant in extra cellular fluid (1) Na+ (2) K+ (3) Mg+2 (4) Zn+ An example of fructosan is : (1) Inulin (2) Cellulose (3) Starch (4) Glycogen In which from animal stores maximum amount of food : (1) Glycogen (2) Starch (3) Lipid (4) Glucose Erythrose sugar is (1) Tetrose (2) Pentose (3) Hexose (4) Polysaccharide Amongst the naturally occurring sugars which is the sweetest one (1) Glucose (2) Saccharine (3) Fructose (4) Sucrose

417 35.

36.

37.

38.

39.

40.

Which is the least sweetest sugar (1) Lactose (2) Sucrose (3) Fructose (4) Galactose Maximum element (by weight) in the protoplasm, is (1) Carbon (2) Hydrogen (3) Oxygen (4) Nitrogen Which of the following is not a protein? (1) Keratin (2) Wool (3) Chitin (4) Collagen Which carbohydrate does not change the colour of Benedict solution (1) Sucrose (2) Glucose (3) Fructose (4) Galactose Most of the proteins present in protoplasm show following type of configuration (1) Primary (2) Secondary (3) Tertiary (4) Quaternary With reference to double stranded DNA, The following ratio is always constant for all species A+T G+C (1) (2) G+C A+T (3) Both (1) and (2)

41.

42.

43.

44.

45.

46.

47.

(4)

A+G T+C

Which of the following component is minimum in the cellular pool? (1) Water (2) Protein (3) Lipid (4) Carbohydrate Which of the following is not a Hexose sugar? (1) Fructose (2) Mannose (3) Galactose (4) Arabinose About 93% of cellular material is composed of three elements which are (1) Carbon, Nitrogen & Hydrogen (2) Carbon, Oxygen & Hydrogen (3) Carbon, Nitrogen & Oxygen (4) Oxygen, Hydrogen & Calcium Which of the following macromolecule is the most diversephysically & chemically? (1) Nucleic acid (2) Protein (3) Polysaccharide (4) Lipid Amongst the natural materials the largest amount of cellulose occurs in (1) Wood (2) Cotton (3) Jute (4) Cereals Following compound is not a true lipid (1) Glycolipid (2) Lecithin (3) Cholesterol (4) Cephalin Prostaglandins are : (1) Derivaives of PUFA (2) Simple lipid (3) Wax (4) Carbohydrate

418 48.

49.

50.

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53.

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55.

56.

57.

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BIOLOGY Most abundant mineral element in human body is (1) K+ (2) Mg+2 (3) Na+ (4) Ca+2 Peppermint(Menthol) and Camphor are chemically (1) Proteins (2) Sugars (3) Lipids (4) Glycoproteins Which of the following is not a polyunsaturated fatty acid? (1) Linolenic acid (2) Oleic acid (3) Arachidonic acid (4) Linoleic acid ATP is (1) Nucleotide with ribose sugar (2) Nitrogenous base (3) Nucleoside with deoxyribose sugar (4) Nucleoside with ribose sugar The smallest RNA is (1) m RNA (2) t RNA (3) r RNA (4) A monomer The radius of DNA helix is (1) 10 A0 (2) 20 A0 (3) 10 nm (4) 20 nm Most complex amino acid is : (1) Glutamine (2) Tryptophan (3) Tyrosine (4) Phenylalanine In quaternary configuration of protein, disulphide bond may form between following amino acids (1) Methionine and serine (2) Tyrosine and valine (3) Methionine and crysteine (4) Proline and cysteine Except glycine all amino acids in protein are (1) Dextrorotatory (2) Laevorotatory (3) Non-rotatory (4) Both (1) and (2) The pairing of A = T, and G ≡ C is the universal phenomenon of DNA. From this we can deduce all the followings except (1) A+ T = G + C (2) Ratio of A: T is one (3) Guanine equals Cytosine (4) Nitrogenous bases in the two strands are complementary Cellobiose is (1) Monosaccharide (2) Disaccharide (3) Polysaccharide (4) Not a carbohydrate Which of the following is non-reducing sugar (1) Glycogen (2) Trehalose (3) Sucrose (4) All of these Mark the odd pair in the followings (1) Amino acid – protein (2) Nucleotide – DNA (3) Glycerol – fatty acid (4) Monosaccharide – cellulose

61.

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64.

65.

66.

67.

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70.

The differences between RNA and DNA are because of different (1) Sugar and phosphate (2) Base and sugar (3) Phosphate and base (4) Sugar only A co-enzyme is (1) An enzyme that occurs in different tissues but performs the same function (2) Inorganic substance that help digestive enzymes (3) Organic and non- protein in nature that help in activating the metabolic enzymes (4) Protein part of a holoenzyme For better enzymatic action (1) The value of Km should be low (2) Affinity of the substance should be low (3) The value of the Km should be high (4) None of these is true In which of the following type of enzymatic reaction, the inhibitor substance binds with the active site (1) Allostearic (2) Competitive (3) Non-competitive (4) All of these Enzymes are generally absent in (1) Viruses (2) Fungi (3) Algae (4) Bacteria Enzymes in the body are synthesized in (1) Glandular epithelium (2) Gut lining (3) All living cells (4) None of these Most enzymes consist of two parts i.e. (1) Holoenzyme and Prosthetic group (2) Enzyme and coenzyme (3) Apoenzyme and enzyme (4) Apoenzyme and Co-factor Below freezing point an enzyme is (1) Unaffected (2) Inactivated (3) Slightly inactivated (4) Killed Ribozyme is (1) Enzyme whose cofactor is RNA (2) RNA with enzyme activity (3) Enzyme by which RNA is formed (4) A conjugated protein having ribose sugar Substrate concentration at which an enzyme attains half of its maximum velocity is (1) Half life of enzyme (2) Km-constant of enzyme (3) Concentration ratio (4) None

BIOMOLECULES : ENZYMES, MINERALS & VITAMINS 71.

72.

73.

74.

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76.

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78.

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Buchner discovered a complex enzyme system from yeast cells. His enzyme was : (1) Amylase which induces digestion of cellulose (2) Zymase complex which induces synthesis of vitamins (3) Zymase complex which induces synthesis of ethanol (4) Catalytic RNA like Ribozyme An example of competitive inhibition of an enzyme is the inhibition of (1) Succinic dehydrogenase by malonic acid (2) Cytochrome oxidase by cyanide (3) Hexokinase by glucose 6- phosphate (4) Carbonic anhydrase by carbon- di- oxide Sulpha drugs are antibacterial and prevent the synthesis of folic acid. This type of enzymatic inhibition is (1) Allostearic inhibition (2) Competitive inhibition (3) Non-competitive- inhibition (4) None of these Enzymes generally have (1) Same pH and temperature optima (2) Same pH but different temperature optima (3) Different pH but same temperature optima (4) Different pH and Different temperature optima Following type of enzymes are used in industries (1) Allostearic enzymes (2) Immobilised enzymes (3) Holo -enzymes (4) Yellow enzymes Turn over number of enzyme depends upon (1) Size of enzyme molecule (2) Number of the active sites (3) Concentration of substrate molecule (4) Molecular weight of enzyme Abzymes are (1) Abnormal enzymes (2) Enzymes acting on antibodies (3) Antibodies acting as enzymes (4) Enzymes which are non-protein in nature Co-enzyme is (1) Always a protein (2) Often a metal (3) Always an inorganic compound (4) Often a Vitamin LDH catalyses lactic acid to pyruvic acid. It is an example of (1) Isozyme (2) Lysozyme (3) Coenzyme (4) Transferase Which of the following is the best evidence for the lock and key theory of enzymatic action (1) All isolated enzymes have been identified as proteins (2) Enzymes are formed in living organisms only

419

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87.

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92.

(3) Compounds similar in structure to the substrate inhibit the reaction (4) Enzymes determine the direction of a reaction The term enzyme was coined by (1) Kuhne (2) C. Funk (3) Starling (4) Karlson The Km value of the enzyme is the value of the substrate concentration at which the reaction reaches to (1) Zero (2) 2 Vmax (3) ½ Vmax (4) ¼ Vmax If a chemical does not bind with the active site and is also not the end product of the other enzymatic reaction, but still inhibits the enzymatic reaction. Such inhibition is called (1) Non- competitive inhibition (2) Allostearic inhibition (3) Competitive inhibition (4) None of these Which one of the following vitamins serves as a coenzyme in transamination and decarboxylation of amino acid metabolism (1) Pantothenic acid (2) Folic acid (3) Pyridoxine (4) Thiamine The coenzyme–I is derived from (1) Pantothenic acid (2) Vit P-P (3) Pyridoxine (4) None of these Vitamin-C is an example of : (1) Amino Sugar (2) Sugar alcohol (3) Sugar acid (4) Polysaccharide The vitamin that promotes the synthesis of collagen fibres and helps in healing, is (1) Vitamin A (2) Vitamin C (3) Vitamin K (4) Vitamin E Which of the vitamin inhibits the oxidation of unsaturated fatty acids and vitamin A (1) Vitamin K (2) Vitamin E (3) Vitamin C (4) Folic acid Most of the animals (not human) can synthesize following vitamin from glucose (1) Vitamin C (2) Vitamin B1 (3) Vitamin B12 (4) Vitamin A Which of the followings set of food items is rich in potassium (1) Sea weed, onion and sea fish (2) Banana, date and potato (3) Milk, eggs and pulses (4) Egg yolk, liver and nuts Which vitamin acts as coenzyme in hydrogen transport? (1) Pantothenic acid (2) Thiamin (3) Niacin (4) Pyridoxine Which of the following is a vitamin? (1) Thymine (2) Thiamin (3) Thymitin (4) Threonine

420 93.

94.

95.

96.

97.

BIOLOGY Which of the following mineral is required in the food as macro-element (1) Iodine (2) Iron (3) Magnesium (4) Cobalt Which of the following vitamin is not having coenzyme activity (1) Cholecalciferol (2) Tocopherol (3) Menadione (4) All the above A person comes to the doctor with complain of muscle wasting, weakness and difficulty in walking. He used polished rice in diet. What is the probable diagnosis (1) Dry beri-beri (2) Wet beri-beri (3) Scurvy (4) Pellegra Nicotinic acid occurs in (1) Fresh tobacco leaves (2) Fresh meat and eggs (3) Cereals and Citrus fruits (4) Fresh Carrot and peaches Persons having maize as a staple food develop the symptoms of

(1) Beri-Beri (2) Pellagra (3) Night Blindness (4) Anemia 98. A person, suffering from cheliosis, will require (1) Thiamine (2) Riboflavin (3) Pantothenic acid (4) Nicotinic acid 99. Which of the following mineral is the component of the maximum number of enzymes, including the fastest working enzyme also (1) Zn (2) Mg (3) Cu (4) Mn 100. Antibody synthesis is impaired in the deficiency of (1) Vitamin C (2) Folic acid (3) Menadione (4) Niacin 101. Heart enlargement and paralysis can occur due to the deficiency of the following vitamin (1) Vitamin E (2) Vitamin B1 (3) Vitamin B6 (4) Vitamin B12 102. Humans can synthesize following vitamin/s (1) B12 (2) Folic acid (3) A and D (4) All of these

BIOMOLECULES : ENZYMES, MINERALS & VITAMINS

421

ANSWER KEY EXERCISE 1 : NCERT BASED QUESTIONS 1. 6. 11. 16. 21. 26.

(3) (4) (3) (3) (1) (3)

2. 7. 12. 17. 22. 27.

(4) (4) (2) (2) (4) (4)

3. 8. 13. 18. 23. 28.

(4) (3) (4) (4) (4) (4)

4. 9. 14. 19. 24. 29.

(1) (3) (2) (3) (2) (4)

5. 10. 15. 20. 25.

(4) (2) (1) (4) (4)

EXERCISE 2 : WINDOW TO COMPETITIVE EXAMS 1. 6. 11. 16. 21. 26. 31. 36. 41. 46. 51. 56. 61. 66. 71. 76. 81. 86. 91. 96. 101. 106. 111. 116. 121. 126. 131. 136. 141. 146. 151. 156. 161. 166. 171. 176. 181. 186. 191. 196.

(4) (2) (1) (4) (1) (1) (3) (2) (3) (3) (4) (2) (2) (2) (4) (4) (3) (2) (4) (3) (4) (1) (1) (2) (3) (2) (1) (2) (1) (3) (1) (2) (2) (1) (4) (2) (2) (2) (1) (1)

2. 7. 12. 17. 22. 27. 32. 37. 42. 47. 52. 57. 62. 67. 72. 77. 82. 87. 92. 97. 102. 107. 112. 117. 122. 127. 132. 137. 142. 147. 152. 157. 162. 167. 172. 177. 182. 187. 192. 197.

(2) (1) (3) (2) (4) (3) (1) (3) (1) (3) (1) (4) (2) (1) (1) (3) (2) (1) (2) (2) (1) (2) (2) (3) (4) (4) (3) (3) (4) (3) (1) (3) (2) (1) (1) (3) (2) (3) (4) (2)

3. 8. 13. 18. 23. 28. 33. 38. 43. 48. 53. 58. 63. 68. 73. 78. 83. 88. 93. 98. 103. 108. 113. 118. 123. 128. 133. 138. 143. 148. 153. 158. 163. 168. 173. 178. 183. 188. 193. 198.

(4) (2) (3) (4) (1) (4) (3) (3) (2) (3) (1) (2) (1) (3) (2) (3) (2) (2) (4) (3) (4) (3) (2) (4) (1) (4) (2) (1) (1) (2) (2) (3) (1) (1) (2) (1) (4) (3) (1) (2)

4. 9. 14. 19. 24. 29. 34. 39. 44. 49. 54. 59. 64. 69. 74. 79. 84. 89. 94. 99. 104. 109. 114. 119. 124. 129. 134. 139. 144. 149. 154. 159. 164. 169. 174. 179. 184. 189. 194. 199.

(1) (1) (3) (2) (1) (2) (2) (3) (2) (3) (1) (2) (4) (1) (3) (2) (2) (1) (2) (3) (4) (4) (2) (1) (4) (3) (1) (2) (1) (4) (4) (1) (4) (2) (1) (1) (3) (3) (1) (3)

5. 10. 15. 20. 25. 30. 35. 40. 45. 50. 55. 60. 65. 70. 75. 80. 85. 90. 95. 100. 105. 110. 115. 120. 125. 130. 135. 140. 145. 150. 155. 160. 165. 170. 175. 180. 185. 190. 195. 200.

(3) (3) (2) (1) (1) (3) (3) (1) (2) (3) (1) (3) (2) (4) (3) (3) (1) (4) (1) (2) (3) (3) (4) (3) (2) (1) (1) (3) (4) (2) (3) (4) (3) (2) (4) (2) (4) (3) (4) (2)

201. 206. 211. 216.

(3) (2) (3) (2)

202. 207. 212. 217.

(1) (2) (3) (2)

203. 208. 213. 218.

(3) (3) (3) (3)

204. 209. 214. 219.

(3) (2) (2) (4)

205. 210. 215. 220.

(2) (3) (2) (3)

EXERCISE 3 : TEST YOURSELF 1.

(4)

2.

(2)

Common fruit sugar is fructose.

3.

(3)

Starch and glycogen are polymers of α− glucose while cellulose is the polymer of β-glucose

4.

(4)

Raffinose is a tri-saccharide while other three are mono-saccharides.

5.

(1)

Threonine is a hydroxy- amino acid and does not have benzene ring.

6. 9.

(4) (2)

7. (1) 8. (2) Sterol has three- hexane and one Pantene- rings.

10.

(2)

Diosgenin is obtained from Yam plant.

11.

(2)

Cysteine also contains sulphur but is a non-essential amino acid.

12.

(3)

Chitin is the polymer of acetyl- glucosamine.

13.

(2)

Arginine is also a basic amino acid.

14. 17.

(4) (3)

15. (1) 16. (3) Silk fibroin has β-pleated structure.

18.

(3)

Disulphide bond, hydrophobic bond and hydrophilic bonds are present in tertiary structure of protein.

19.

(2)

20.

(2)

These two acids do not have double bonds.

21.

(2)

Ornithine (amino acid) is not a standard amino acid.

22. 27.

(3) (1)

23. (2) 24. (2) 25. (2) Sudan III test is used for lipids.

28.

(3)

Sclero-proteins are also known as fibrous proteins.

29.

(1)

Amongst disaccharides the sucrose is a non-reducing one.

30.

(1)

31.

33.

(1)

Erythrose is a monosaccharide with four carbon atoms.

34.

(3)

Saccharine is a synthetic compound and not a sugar.

35.

(1)

Lactose is maximum in human milk.

36.

(3)

Oxygen is about 63% in the protoplasm.

37

(3)

Chitin is a polysaccharide.

38.

(1)

39.

(1)

(3)

32.

40.

26.

(4)

(3)

(4)

422

BIOLOGY

41

(4)

Carbohydrate is about 1% in cellular pool.

73

(2)

Sulpha drugs compete for PABA.

42

(4)

Arabinose like ribose is a pentose sugar.

74

(3)

43.

(2)

44

(2)

Even in a small protein of only 100 amino acids, the 20 different amino acids may combine in 20100 different ways.

Respiratory enzymes work at almost the same pH but digestive enzymes generally work at different pH.

75

(2)

45

(2)

Cotton contains about 90% cellulose.

Immobilised enzymes are covalently attached to solid support, or present in artificial cells for protection from proteolytic enzymes.

46.

(3)

47.

76

(2)

Carbonic anhydrase has maximum turn over number.

49

(3)

Menthol and camphor are terpenes (complex lipids)

77

(3)

The non-protein enzymes are ribozymes.

50

(2)

Oleic acid is an unsaturated one, but it is not polyunsaturated as it has only one double bond.

78

(4)

Co-enzymes are always organic in nature.

79

(1)

51

(1)

Adenosine of ATP contains sugar (ribose) and adenine (a purine- base).

Isozymes are similar in structure but some of their chemical properties are different.

80

(3)

52

(2)

t-RNA is also known as soluble RNA or adaptive RNA.

Another key with similar configuration can open the same lock.

81.

(1)

82.

53

(1)

The diameter of DNA helix is 2 nm (= 20 Å)

84

(3)

54.

(2)

55.

85

(2)

This vitamin is also called as B6.

57

(1)

We can, however, predict that A+G = T+C.

86.

(3)

87.

58

(2)

Cellobiose contains two β-glucoses.

88

(2)

Vitamin-E is an antioxidant vitamin.

59

(4)

Trehalose is a non reducing disaccharide, present in micro organisms.

89.

(1)

60

(3)

As in other cases, the fatty acid is not a polymer of glycerol.

90

(2)

Onion and Sea-fish etc. are iodine-rich.

91

(3)

Niacin forms NAD and NADP (co-enzymes).

61

(2)

The special base- pair and the sugar in RNA is Uracil and ribose respectively.

92

(2)

Thymine is a nitrogenous base (Pyrimidine) and thymitin is the hormone of thymus.

62.

(3)

93

(3)

63

(1)

Iron is placed between micro and macro elements but is classified in micro- elements.

94.

(4)

95.

96

(2)

Nicotinic acid is vitamin Niacin and is not related to Nicotine (tobacco).

97

(2)

Maize protein lacks Tryptophan amino acid due to which Niacin is not formed.

98.

(2)

99.

100

(2)

Folic acid helps in the synthesis of nitrogenous bases which regulate cell division.

101 102

(2) The deficiency of vitamin-B1 causes polyneuritis. (3) Vitamin-B12 and folic acids are synthesized by microflora of intestine and not by the cells of human body.

(1)

(3)

48.

(4)

56. (2)

The Km value is inversely proportional to its affinity of enzyme with the substrate.

64

(2)

65.

(1)

66

(3)

The enzymes may be respiratory or digestive.

67.

(4)

68.

69

(2)

r - RNA has enzymatic activity (Cech and Altman, 1989-Nobel prize )

70.

(2)

71.

72

(1)

Malonic acid resembles succinic acid in molecular configuration.

The inhibitory substance resembles the substrate in configuration.

(2)

(3)

(3)

83. (1)

The vitamin P-P is pellagra preventive vitamin. (2)

(1)

(1)

10

G1 G

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Cell Cycle and Cell Division At a Glance

While going through the chapter pay special attention to the following – Terms and Definition – (1) Synaptonemal complex (3) Terminalization (5) Bouquet stage (7) G0 stage (9) Karyochorosis (11) Disjunction (13) Interkinesis (15) Heterotypic division Differences – (1) Cytokinesis and Karyokinesis

 (2)

Chiasmata

(4) (6) (8) (10) (12) (14)

Brachymeiosis Tetrad Asters Recombinase enzyme Bivalents Homotypic division

Cell cycle

     





 

Cytokinesis in plants and animals





 

G1 Phase S Phase

G2 Phase

Mitotic Phase Prophase

Metaphase Anaphase

Telophase

Signi�icance of mitosis

Meiosis



  

Interphase

Mitosis



(2)

Phases of cell cycle

Signi�icance of meiosis

New cells arise from the pre-existing cells by process known as cell division. Cell division is an important phenomenon that occurs in all living organisms. In unicellular organisms, cell division directly produces two individual thus, it is a method of reproduction in these organisms. In multicellular organisms, life begins from a single cell zygote or fertilized egg, which divides & redivides to form a complete organisms. Each parent cell give rise to two daughter cells each time they divide. These newly formed daughter cells themselves grow and divide, giving rise to a new cell population that is formed by the growth and division of a single parental cell and its progeny.

CELL CYCLE 

Cell cycle is a genetically controlled series of changes that occur in a newly formed cell by which it duplicates its genome, synthesises other constituents, undergoes growth and divides to form two daughter cells.



Connecting Concepts Although cell growth (in terms of cytoplasmic increase) is a continuous process, DNA  The main reason for cell division synthesis occurs only during one specific stage in the cell cycle.



The replicated chromosomes (DNA) are then distributed to daughter nuclei by a complex ratio or karyoplasmic ratio which is series of events during cell division. These events are themselves under genetic control.



Cell cycle consists of two basic phases, states or periods. There is a long non-dividing mass of cell. It gets disturbed due to growing I-phase (Inter-phase) and a short-dividing M-phase. Both have substages. continuous cell growth. Further cell M-phase is the period or phase of actual cell division. division is also necessary for continuity

is to maintain the nucleocytoplasmic

ratio between nucleus and cytoplasmic

of organism or species.

424

BIOLOGY

Phases of Cell Cycle

Connecting Concepts



Interphase : The resting phase or stage between the two mitotic divisions is called inter-mitotic phase or interphase. During interphase, cell prepares for division by undergoing both cell growth and DNA replication in an orderly manner.



Most of DNA, RNA and protein are made during interphase, so it is the period when metabolic activity is greatest.

 Time interval between two successive divisions is called generation  time.  Nerve cells do not divide after birth and, therefore interphase last  throughout the life of the individual.  In G1 phase a cell can undergo three processes. (a) in S-phase (b) enter in quiescent stage or G0 phase. (c) Stop cell cycle and undergo (i) differentiation. The deciding factor is availability of energy rich compounds and mitogens. The point where this decision is made is known as check point. Once this check point is crossed, the cell will divide even under unfavourable conditions.  Go phase: Some cells in the adult animals do not appear to exhibit division (e.g., heart cells) and many other cells (ii) divide only occasionally. These cells that do not divide further exit G1 phase to enter an inactive stage is called quiescent stage (G0) of the cell cycle. Cell in this stage remain metabolically active but no longer proliferate unless depending on the requirement of the organism.

The interphase is the longest phase of the mitotic cycle, last more than 95% of the duration of cell cycle. It has three sub-phases: G1, S and G2 which occurs in this order followed by M phase. Different eukaryotic cells vary in the length of time taken to complete an entire cell cycle; they also differ in the relative proportions of time allotted to each of the four stages. Thus, in continuously dividing cells, an individual cell passes through the following four phases of cell cycle. G1 phase: (G stands for gap) : In this phase synthesis of substrate and enzyme necessary for DNA synthesis take place. Therefore, G1 is marked by the transcription of rRNA, tRNA, mRNA and synthesis of different types of proteins. It corresponds to the interval between mitosis and initiation of DNA replication. During G1 phase the cell is metabolically active and continuously grows but does not replicate its DNA. •

Time taken for completion of this phase is about 30–40% of the total cell cycle (mitotic cycle).

•

Decision of cell division occurs during this phase.

S phase: During S or synthesis phase, replication or duplication of chromosomal DNA and synthesis of histone proteins takes place. During this time the amount of DNA per cell doubles. •

Time taken for completion of this phase is 30–50% of total cell cycle.

•

If the initial amount of DNA is denoted as 2C then it increases to 4C. However, there is no increase in the chromosome number; if the cell has diploid or 2n number of chromosomes at G1, even after S phase the number of chromosomes remains the same, i.e., 2n. In animal cells, during the S-phase, DNA replication begins in the nucleus and the centriole duplicates in the cytoplasm.

•

In contrast, in rapidly growing bacteria DNA synthesis occurs from the time a cell originates to the time it gives rise to daughter cells by division. Likewise, in simple eukaryotes such as yeast, DNA synthesis takes place throughout the interphase and ceases only during the brief period of nuclear and cell division (i.e., M phase).

•

Once the cell entered in S phase, it would proceed to division without any interruption.

(iii) G2 phase: It is the post-DNA synthesis phase. •

Time taken for completion of this phase is 10–20% of a total cell cycle.

•

During the G2 phase, proteins are synthesized for mitosis while cell growth continues.

(iv) M-phase or mitotic phase or meiotic phase : It is actual cell division phase followed by G2 phase. •

Time taken for completion of this phase is 5–10% of the total cell cycle and hence it is shortest of all the 4-phases.

•

It is final phase of cell cycle. It consists of karyokinesis (division of nucleus) and cytokinesis (division of cell protoplasm) to form two daughter cells.

CELL CYCLE AND CELL DIVISION

425

G1 G

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





 Various phases of cell cycle are

In animals, mitotic cell division is only seen in the diploid somatic cells. While plants can controlled by proteins cyclins and cyclin dependent kinases (CDKs or cdc kinases) show mitotic divisions in both haploid and diploid cells.

MITOSIS 

Connecting Concepts

Flemming (1882) coined the term mitosis. However , mitosis was first observed in plants by E. Strasburger (1875) and in animals by W. Flemming (1879). It is also called as equational division as the number of chromosomes in the parent and progeny cells is the same. So mitosis increase in number of cells without any change in genetic constitution. It is a continuous process but for convenience it is usually divided into several stages or phases, viz., prophase, metaphase, anaphase, telophase and cytokinesis. Parent cell

Prophase Metaphase

Anaphase

Chromatin condenses into chromosomes. Nuclear envelope disappears Chromosomes align at the equatorial plate. Sister chromatids separate. Centromeres divide. Telophase Chromatin expands. Cytoplasm divides. Two daughter cells

that take part in phosphorylation and dephosphorylation

 Mitosis is also known as somatic division because it takes place during formation of somatic or body cells. Mitosis is studied in plants in the regions of meristems, e.g. stem tip, root tip. In animals it is studied in bone marrow, skin, base of nails, etc.  Mitosis is centric in animal cells and acentric (without participation of centrosome) in plants.  The agents which stimulate cell division are called mitogens, e.g., cytokinins, some steroids, platelet derived growth factor (PDGF), lymphokines.  There are some agents which inhibit cell division. They are called mitotic poisons, e.g., azides, cyanides, colchicine.  Besides mitogens, cells are stimulated to divide in achieving a particular size, critical decrease in surface volume ratio and critical decrease in nucleocytoplasmic ratio.

 The rate of cell division is not the same in various stages of life cycle. Fertilised Prophase egg or zygote divides repeatedly to form a large number of cells, upto 6 ×1012  The prophase is the first and the longest phase of the mitosis. cells. Later on divisions are get slow The prophase includes five events: down and restricted in certain regions  The beginning of prophase is indicated by the onset of chromosome coiling and like meristematic regions in plants, condensation. As a result, chromosomes become distinctly visible as thin threads inside bone marrow and germinal tissue in the nucleus. At the same time, the cell becomes spheroid, more refractile, and viscous. animals. Fig. 10.2 Mitosis

426

BIOLOGY Connecting Concepts



 Time taken by phases of cell cycle varies in different organisms and also in  different tissues of same organisms, e.g., in Vicia faba (Broad bean or Bakla) Phases of cell cycle Duration (i)

G1-phase

12 hrs

(ii)

S-phase

6 hrs

(iii) G2-phase

12 hrs

(iv) M-phase or mitotic phase

1 hr

The two pairs of centrioles formed by duplication during ‘S’ phase of interphase, separate and migrate to occupy positions on opposite sides of the nucleus.



Initiation of spindle formation begins during prophase, although the spindle is not fully functional until metaphase. Microtubules (proteinaceous components) of cell cytoplasm help in this process.



Cells at the end of prophase do not have Golgi complex, endoplasmic reticulum, nucleolus and the nuclear envelope.

Metaphase

 Therefore, cell cycle here is of 31  hrs (Interphase—30 hrs and mitotic phase—1 hr).   In meiotic cell G2 phase is either absent or very short i.e. meiotic division (M-phase) occurs just after completion of DNA-synthesis (S-phase).

Each prophase chromosome is composed of two coiled identical filaments, the sister chromatids, which are held together by a centromere.



 In amitosis, nucleus elongates, constricts in the middle and divides directly into two daughter nuclei. Chromatin does not condense to form chromosomes. Spindle apparatus is not  formed. Nuclear division is followed by  cytokinesis. It occurs through cleavage or constriction, e.g., cartilage cells, meganucleus of Paramoecium, cells of foetal membranes and endosperm. As  amitosis does not distribute chromatin, it leads to structural and functional irregularities.

At metaphase complete disintegration of the nuclear envelope, alignment of chromosome and formation of the spindle apparatus takes place. The spindle apparatus is a microtubular structure that extends from pole to pole. Those cells that have centrioles typically also have asters, which are fibres radiating out in all directions from the poles. Each of the astral and spindle fibres is actually bundles of microtubules. Small disc-shaped structures at the surface of the centromere are called kinetochores. These are the sites of attachment of spindle fibres. During metaphase all the chromosome align to center of cell, the chromosomes become attached to some of the spindle fibres by their kinetochores. 97% tubulin protein (protein of microtubules) and 3% RNA are present in spindle fibres. Spindle microtubules are polar, their + ends are fast growing facing equator while –ve ends are slow growing face poles. Alignment of chromosome due to contraction of chromosome or kinetochore fibre is called congression. The two sister chromatids by virtue of their kinetochores and attached fibres are pulled towards opposite poles. Because they are held together at the centromere, there is pull in both directions at once, resulting in oscillatory movements that eventually align all chromosomes in one plane. This plane is called equatorial plane or metaphasic plane.

 A spindle fibre consists of 4–20  microtubules formed of protein tubulin.

The fibres of spindle which connect to the chromosomes are called the chromosomal fibres; those that extend without interruption from one pole to the other are the continuous fibres.

 In dividing animal cells, the spindle  bears asters at the two poles. Such a spindle is called amphiaster or centric. In plant cells spindle is acentric or  anastral.

Centromeres of all chromosomes are present over the equator, whereas its arms project in different directions. Morphology of chromosome can be observed and studied, clearly under the microscope in metaphase.

 In many protists, fungi and algae, the Anaphase nuclear envelope does not degenerate It is phase of shortest duration. during mitosis. Instead, spindle is  formed inside the nucleus. It is called  Mitotic anaphase begins with centromere division. The two daughter chromatids, now free intranuclear mitosis or karyochorosis. from each other, move towards their respective poles.



Because they are being pulled by their kinetochores, the chromatids would assume V- shape, L- shape, J-shape or I-shape in metacentric, submetacentric, acrocentric and telocentric chromosome respectively.



At the same time as the chromatids move toward their poles, the poles themselves move further apart. The chromosomes move due to shortening of chromosomal fibres and the poles are pushed apart by lengthening (or stretching) of continuous or pole-to-pole fibres.



Now, the two sister chromatids are separate structures. These are the chromosomes of future daughter nuclei.

CELL CYCLE AND CELL DIVISION

Telophase

427 Connecting Concepts  Shape of chromosome are studied



In telophase, two diploid sets of daughter chromosomes gathered at opposite poles. Start in anaphase. to uncoil and become mass of chromatin. Their identity is lost as discrete elements.



The nucleolus condense and reappear. The spindle fibres disperse. The nuclear envelope in 10 minutes to several hours. is assembled around the chromatin mass and endoplasmic reticulum reform again thus Further on increasing the surrounding temperature, lesser the time taken in forming two daughter nuclei.

 Cell complete their mitotic division

division.  A deadly disease cancers is due to uncontrolled cell division. Carcinogens are cancer causing agents which are UV radiation and chemicals like benzpyrene, aflatoxin, mustard gas etc.

Fig. 10.3 Different stages in the mitotic division of a plant cell

Cytokinesis 

Karyokinesis (division of nucleus into two) is followed by cytokinesis i.e., division of cytoplasm into two daughter cells, which starts towards the middle of anaphase and is completed simultaneously by the end of telophase.



Plant cells : Wall formation starts in the centre of the cell and grows outward to meet the existing lateral walls (centrifugal). In the equatorial region middle part of spindle persists and gets interdigitated with microtubules to form a complex structure called phragmoplast. The vesicle of dictyosome (Golgi complex) and the membranous elements of the ER accumulate in the region of the equator and fuse to form the cell plate dividing it into two equal or unequal daughter cells.



At the time of cytoplasmic division, organelles like mitochondria, Golgi complex, lysosomes and plastids get distributed between the two daughter cells.



Animal cells : A furrow appears in the cell membrane at the equator and progresses from the periphery to centre (centripetal). It also occurs in some lower plant.

428

BIOLOGY

SIGNIFICANCE OF MITOSIS 

Mitosis is necessary for the maintenance and perpetuation of life.



It helps in the maintaining the amount of DNA and RNA in the cell.



Mitotic divisions of vegetative or somatic cells are responsible for growth and development of organism.



The old decaying and dead cells of body are replaced by mitosis.



In certain organisms, mitosis is involved in asexual reproduction.



The gonads and the seed cells depend on the mitosis for the increase in their number.



The cleavage of egg and division of blastula during embryogenesis are mitotic divisions.



Mitotic divisions in the apical and lateral cambium, results in a continuous growth of plants throughout their life.

MEIOSIS

Connecting Concepts  Brachymeiosis is unusual meiosis occur in ascus of certain fungi (Pyronema confluens). In this type of division a reduction division followed by the two usual mitotic division occurs to restore the haploid condition in fungi in which double fertilization has produced a tetraploid primary ascus nucleus.



Farmer and Moore (1905) – coined the term meiosis.



Meiosis is characterized by two successive divisions of the cytoplasm and nuclei (meiosis I and meiosis II). These haploid cells either become or give rise to gametes.



Meiosis ensures the production of haploid phase in the life cycle of sexually reproducing organisms whereas fertilisation restores the diploid phase. Thus, meiosis is required to run the reproductive cycle of eukaryotes.



Meiosis involves two sequential cycles of nuclear and cell division called meiosis I and meiosis II but only a single cycle of DNA replication.



Meiosis involves pairing of homologous chromosomes and recombination between them.



Four haploid cells are formed at the end of meiosis II. Meiotic events can be grouped under the following phases: Meiosis I Prophase I Metaphase I Anaphase I Telophase I

Meiosis II Prophase II Metaphase II Anaphase II Telophase II

Meiosis I 

Meiosis starts after an interphase which is not very different from that of a mitotic interphase.



It is the actual reduction division and known as heterotypic division as it converts a diploid cell into haploid cells. In meiosis I, the two chromatids of a chromosome often become different due to crossing over.



The first stage of both meiosis I and II is prophase. The prophase of first meiotic division is very significant because most cytogenetical events such as synapsis, crossing over, etc., occur during this phase.

Prophase I The first prophase is the longest stage of the meiotic division. It includes following substages: Leptotene 

During this stage, the chromosomes become gradually visible under the light microscope. The compaction of chromosomes continues throughout leptotene.



The chromosomes at this stage take up a specific converge toward one side of the nucleus, where the centrosome lies (the bouquet stage).



The centriole duplicates and each daughter centriole migrates towards the opposite poles of the cells. On reaching at the poles, each centriole duplicates again and thus, each pole of cell possesses two centrioles or a single diplosome.

CELL CYCLE AND CELL DIVISION

429

Zygotene 

Leptotene stage is followed by zygotene. In this stage, the pairing of homologous chromosomes takes place. In homologous chromosome pair one chromosome comes from the mother (by ova) and one from father (by sperm) are attracted towards each other and their pairing takes place. The pairing of the homologous chromosomes is known as synapsis forming bivalents.

Synaptonemal Complex 

The pairing of the homologous chromosomes is very specific i.e. it brings alleles of homologous chromosome exactly opposite to each other.



Moses in 1956 discovered synaptonemal complex, which is paired homologous chromosomes held together by nucleoproteins.



This complex extends along the whole length of the paired chromosomes and is usually anchored at either end to the nuclear envelope.



Synaptonemal pairing produces an opportunity for crossing over that occurs during pachytene and thus facilitates the genetic recombination. The paired homologous chromosome is called bivalent.

Pachytene

Connecting Concepts  Number of bivalents is half the number of individual chromosomes. Bivalents are actually tetrads but the individual chromatids of the two chromosomes are not clear due to the presence of nucleoprotein core between them. Depending upon the area of initiation, synapis can be procentric (starting from centromeres), proterminal (pairing beginning from telomeric regions and proceeds inward) and intermediate ( = random pairing starts at several points). Pairing proceeds from the starting regions towards other parts in a zipper like manner.



This stage is characterised by the appearance of recombination nodules, the sites at which crossing over occurs between non-sister chromatids of the homologous  In males of Drosophila chromosomes. melanogaster an unusual type of meiosis



Crossing over is the exchange of genetic material between two homologous chromosomes. occurs in which synaptonemal complex It is also an enzyme-mediated process and the enzyme involved is called recombinase. (SC) formation and recombination



Crossing over leads to recombination between homologous chromosomes which is is called achiasmatic meiosis and is completed at the end of pachytene but become linked at the site of crossing over. exceptional, as nearly all eukaryotes

do not occur. This type of meiosis

along with Drosophila females require SC formation and recombination for At diplotene further thickening and shortening of chromosome takes place. The synaptic successful completion of meiosis.

Diplotene 

forces between paired homologues come to an end (synaptonemal complex appears to be  Chiasmata was first seen by dissolved) and chromatid become clear and the bivalents are now called tetrads. Johannsen. 

The chromatids of the paired homologous chromosomes physically joined at one or more  Disjunction is the process of separation of homologous discrete points having X-shaped structure called chiasmata.



In oocytes of some vertebrates, diplotene can last for months or years and form lampbrush chromosomes.



The nucleolus is also diminished but still persists. No nuclear membrane can be seen at this stage.

Diakinesis 

The final stage of meiotic prophase I is diakinesis. At this stage the bivalent chromosomes become more condensed and evenly distributed in the nucleus.



Ordinarily the only distinction between diplotene and diakinesis is the more contracted state of bivalents at diakinesis.



The nucleolus detaches from the nucleolar organizer and ultimately disappears. The nuclear envelope breaks down.



During diakinesis the chiasmata moves from the centromere towards the ends of the chromosomes and the intermediate chiasmata diminish. This type of movement of the chiasmata is known as terminalizaton. The chromatids still remain connected by the terminal chiasmata.

chromosome.

Check Point 1. Give term for each of the following. (a) The period between two successive mitotic divisions. (b) Process of cell division by which the chromosome number is halved. (c) Point at which two sister chromatids are held together. (d) Phase in the cell cycle when protein and RNA are synthesised. (e) Nuclear division.

430

BIOLOGY

Metaphase I  

At metaphase I spindle fibres attach themselves to chromosomes and chromosomes align at the equator. The centromere of each chromosome is directed towards the opposite poles. The repulsive forces between the homologous chromosomes increase greatly and the chromosomes become ready to separate.

Anaphase I 

  

At anaphase I, homologous chromosome pair (one chromosome is from mother and other is from father) with its two chromatids moves towards the opposite poles of the cell and separate from each other. This separation cause two groups of haploid chromosomes at the poles. Due to crossing over, the two chromatids of a chromosome do not resemble with each other in the genetical terms. The chromosomes with single or few terminal chiasmata usually separate more frequently than the longer chromosomes containing many chiasmata.

Telophase I     Connecting Concepts



In telophase, the nuclear membrane and nucleolus reappear. The chromosomes become uncoil. After the karyokinesis, cytokinesis occurs and two haploid cells are formed. This is called diad of cells. Both cells pass through a short resting phase or interphase. During interphase, no DNA replication occurs, so chromosomes at the second prophase are the same double-stranded structures that disappeared at the first telophase. The stage between the two meiotic divisions is called interkinesis and is generally shortlived. Interkinesis is followed by prophase II, which is a much simpler prophase than prophase I.

 In Trillium both telophase I and Meiosis II prophase II are omitted and anaphase I  The first meiotic division is followed by a second meiotic division with or without the directly leads to metaphase II.

Check Point 1. Name the stage of cell division (a) Crossing over occur between homologous chromosome. (b) Stage of synapsis of homologous chromo-some. (c) Stage of initiation of cytokinesis. (d) Movement of daughter chromosome towards pole. (e) Stage of reappearance of nucleoi.

intervening interphase. The second meiotic division is actually the mitotic division known as homotypic division which divides each haploid meiotic cell into two haploid cells.  The second meiotic division includes following four stages: Prophase II  The nuclear membrane and the nucleolus disappear. The chromosomes with two chromatids become short, thick and compact.  At this stage each centriole divides into two and thus, two pairs of centrioles are formed. Each pair of centrioles migrates to the opposite pole.  The microtubules get arranged in the form of spindle at the right angle of the spindle of first meiosis. Metaphase II  The chromosomes get arranged on the equator of the spindle. The microtubules of the spindle are attached with the kinetochores of the chromosomes.  The centromere divides into two and thus each chromosome produces two daughter chromosomes. Anaphase II The daughter chromosomes move towards the opposite poles due to stretching of internal microtubules of the spindle. Telophase II





The chromatids migrate to the opposite poles and now known as chromosomes. The endoplasmic reticulum forms the nuclear envelope around the chromosomes and nucleolus reappears due to synthesis of ribosomal RNA (rRNA) and ribosomal protein. After the karyokinesis, cytokinesis follows resulting in the formation of tetrad of cells i.e., four haploid daughter cells.

CELL CYCLE AND CELL DIVISION

Fig. 10.4 Different stages in the meiotic division of a plant cell

SIGNIFICANCE OF MEIOSIS 

Meiosis is the mechanism by which conservation of specific chromosome number of each species is achieved across generations in sexually reproducing organisms.



It also increases the genetic variability in the population of organisms from one generation to the next by crossing over. The variations are the raw materials of the evolutionary process.

431

432

BIOLOGY

EXERCISE - 1 | NCERT BASED QUESTIONS 1.

Which one of the following is correct option for A, B and C.

4.

B 2N

A C

Mother cell A Meiosis Meiosis Mitosis Mitosis

(1) (2) (3) (4)

5.

C N 2N N 2N

Identify the phases from the graph given below that shows the change in DNA content during various phases (A to D) of mitotic cell cycle. DNA content

2.

B N 2N N 2N

4C 2C

A

B C D

6.

7.

Time

(1)

A G2

B G1

C S

D M

(2)

G2

S

M

G1

S

G1 G2

M

M

G1

S

G2

(3) (4) 3.

Choose and labelled the diagram from the given options.

8.

9.

(ii)

(i) ]

(iv)

10.

(iii)

(1) (i) Chromatid, (ii) Centriole, (iii) Centromere, (iv) Chromosome (2) (i) Chromosome, (ii) Centriole, (iii) Centromere, (iv) Chromatid (3) (i) Chromatid, (ii) Centromere, (iii) Centriole, (iv) Chromosome (4) (i) Chromosome, (ii) Centromere, (iii) Centriole, (iv) Chromatid

11.

12.

Choose the correct statement with respect to mitosis. (1) Chromosomes move to the spindle equator and get aligned along equatorial plate in metaphase (2) Chromatids separate but remain in the centre of the cell in anaphase (3) Chromatids start moving towards opposite poles in telophase (4) Golgi complex and endoplasmic reticulum are still visible at the end of prophase Meiosis I is reductional division. Meiosis II is equational division due to (1) pairing of homologous chromosomes (2) crossing over (3) separation of chromatids (4) disjunction of homologous chromosomes In meiosis, the daughter cells differ from parent cell as well as amongst themselves due to (1) segregation, independent assortment and crossing over (2) segregation and crossing over (3) independent assortment and crossing over (4) segregation and independent assortment Best stage to observe shape, size and number of chromosomes is (1) interphase (2) metaphase (3) prophase (4) telophase Meiosis is evolutionary significant because it results in (1) genetically similar daughters (2) four daughter cells (3) egg and sperm (4) recombinations During cell division, the spindle fibres attach to the chromosome at a region called (1) chromocentre (2) kinetochore (3) centriole (4) chromomere Synapsis occurs between (1) mRNA and ribosomes (2) spindle fibres and centromere (3) two homologous chromosomes (4) a male and a female gamete In cell cycle, DNA replication takes place in (1) G1 phase (2) G2 phase (3) mitotic metaphase (4) S phase A contractile centriole forms during cytokinesis in (1) animals

(2) higher plants

(3) fungi

(4) algae

CELL CYCLE AND CELL DIVISION 13.

The diagram below shows a cell undergoing meiosis assume that crossing over occurs only at the chiasma indicated.

433 17.

Which of the following gametes will NOT be formed from this cell?

14.

15.

(1)

(2)

(3)

(4)

18.

(1) (2) (3) (4) 19.

20. Which of the following diagram is correct for one of the cell at the end of meiosis?

16.

(1)

(2)

(3)

(4)

Centromere is required for (1) movement of chromosomes towards poles (2) cytoplasmic cleavage (3) crossing over (4) transcription

(1) Metaphase (2) Anaphase of mitosis (3) First anaphase of meiosis (4) Second anaphase of meiosis The diagram shows the nuclear contents of a cell.

Which one of the following option is right?

Which one is the right option for the given diagram?

(1) Metaphase (mitosis) (2) Anaphase II (meiosis) (3) Metaphase-I (meiosis) (4) Anaphase (mitosis) A cell undergoing in Prophase I.

The diagram shows a cell whose diploid chromosome number is four. Which one of the following option shows correct stage of cell

21.

22.

Number of pairs of homologous chromosomes 3 3 6 6

Number of chromatids

Number of centromeres

6 12 6 12

12 6 12 6

Reason of ch chromosomal movement in anaphase is (1) astral rays (2) centrioles (3) kinetochore (4) kinetochore and spindle fibres Chromosome exhibit high level of coiling at which phase of karyokinesis ? (1) Prophase (2) Metaphase (3) Telophase (4) Interphase In meiosis (1) division of nucleus twice but replication of DNA only once (2) division of nucleus twice and replication of DNA twice (3) division of nucleus once and replication of DNA is also once (4) division of nucleus once and DNA - replication is twice Gap between meiosis - I and II is called (1) interphase (2) interkinesis (3) diakinesis (4) metakinesis

434 23.

BIOLOGY In the diagram, a cell undergoing meiosis

Which one of the diagrams below shows the next stage in the process?

III. Pairing between homologous (C) Anaphase chromosomes takes place IV. Crossing between homologous (D) Metaphase chromosomes I II III IV (1) A B C D (2) B C D A (3) D C B A (4) C A D B 26. Which of the following events correctly indicates the stages of mitosis? DNA replication

24.

(1)

(2)

(3)

(4)

27.

The following diagram is of a typical cell cycle.

X

Y

G0

e as Ph

ph

Pr o

M

as

e

esis Cytokin se pha e Telo phas ase a h An etap M

Z

Mark the correct option. (1) X - G1; Y - S; Z - G2 (2) X - G2; Y - S; Z - G1 (3) X - G0; Y - S; Z - G2 (4) X - G1; Y - G2; Z - G0 25.

Match the following and choose the correct option. Column I Column II I. Chromosomes are moved (A) Pachytene to spindle equator II. Centromere splits and (B) Zygotene chromatids apart

(1) (2) (3) (4) 28.

Breakdown of nuclear membrane Metaphase Prophase Interphase Metaphase

Division of centromere

Anaphase (1) Interphase Anaphase (2) Interphase Anaphase (3) Telophase Prophase Anaphase (4) Different events that occur during different phases are given below. (A) Centromere splits, chromatids separate and move to opposite poles and they now called chromosome (B) Chromosomes cluster at opposite poles, decondensation of chromosome, reappearance of nuclear membrane, GB, ER and nucleolus (C) Chromosomal replication (D) Kinetochores attach to spindle fibres and chromosome are arranged at equatorial plate (E) Spiration of chromosomes / condensation of chromosomal materials Which of the following option correctly identifies each of the phases described? Interphase

Prophase

Metaphase

Anaphase

Telophase

C C C C

E D E A

D E D D

A A B E

B B A B

Match the following and choose the correct option. Column I Column II I. Terminalization of chiasmata A. Zygotene II. Synapsis B. Diplotene III. Crossing over C. Metaphase I IV. Dissolution of Synaptonemal D. Diakinesis complex V. Best stage for the study of E. Pachytene chiasmata VI. Nuclear membrane and nucleolus disappear VII. Tetrads are arranged on equatorial line

CELL CYCLE AND CELL DIVISION

29.

(1) A - II, B - V, C - VII, D - I, IV, VI, E - III (2) A - II, B - III, C - VII, D - I, IV, VI, E - V (3) A - II, B - VII, C - III, D - I, IV, V, E - VI (4) A - II, B - I, C - IV, D - V, III, E - VI Chiasmata are formed as a result of (1) exchange of parts of paired homologous chromosome (2) exchange of part of unpaired non- homologous chromosome

435

30.

(3) duplication of parts of paired homologous chromosome (4) loss of parts of unpaired non-homologous chromosome Which of the following statement is correct ? (1) DNA is synthesized throughout the cell-cycle. (2) Cell division is inhibited by cytokinin. (3) Chromosome are condensed at S-stage. (4) Only extra chromosomal DNA is replicated at any stage of cell cycle.

436

BIOLOGY

EXERCISE - 2 | Window to Competitive Exams 1.

2.

3.

4.

5.

6. 7.

8.

9.

During the mitosis of human hyla cells the longest period is [CBSE'96] (1) Gap-1-phase (2) S-phase (3) Gap-2-phase (4) M-phase In a cell cycle the RNA synthesis, needed in protein synthesis, occurs in [AMU'96] (1) synthetic period (2) post mitotic gap period (3) premitotic gap period (4) prophase Lampbrush chromosomes occur during [CBSE'96] (1) prophase of mitosis (2) diplotene of meiosis (3) metaphase of meiosis (4) interphase During meiosis [AMU'96] (1) cytokinesis may take place (2) cytokinesis may not take place (3) cytokinesis may or may not take place (4) all of the above Colchicine is employed to diploidize a haploid cell as it [CBSE'96] (1) inhibits mitosis (2) inhibits formation of mitotic spindle (3) allows replication of DNA twice in one cell cycle (4) inhibits formation of centromere Which one is stored in G1-phase? [AMU'96] (1) ATP (2) Tubulin (3) Histone (4) All the above In leptotene, the chromosomes are [CBSE'96] (1) attached to nuclear envelope by one end. (2) attached to nuclear envelope by both ends directly. (3) attached to nuclear envelope by both ends through attachment plate. (4) Both (2) and (3) How many mitotic divisions are needed for a single cell to make 128 cells? [CBSE'97] (1) 7 (2) 14 (3) 28 (4) 64 During which stages (or prophase I substages) of meiosis do you expect to find the bivalents and DNA replication respectively? [AMU'97] (1) Pachytene and interphase (between two meiotic divisions) (2) Pachytene and interphase (just prior to prophase I) (3) Pachytene and S phase (of interphase just prior to prophase I) (4) Zygotene and S phase (of interphase prior to prophase I)

10.

11.

12.

13.

14.

15.

16.

17.

18. 19.

During cell division in apical meristem the nuclear membrane appears in [CBSE'97] (1) metaphase (2) anaphase (3) telophase (4) cytokinesis At the end of prophase, nucleolus disappears because of [AMU'97] (1) its enzymatic dissolution into its macromolecules (2) its dispersion into cytoplasm (3) its dispersion into nucleoplasm (4) its poor stainability A drug called colchicine is shown to interfere specially with spindle microtubules formation during mitosis. This would result in [AMU'98] (1) dehydration of chromosomes (2) despiralization of chromosomes (3) arrest of chromosome movements (4) arrest of centrioles movements How many mitotic divisions are needed for a single cell to make 256 cells? [AMU'98] (1) 8 (2) 16 (c) 32 (4) 64 The stage of meiosis where centromere separate [BHU'98] (1) metaphase I (2) metaphase II (3) anaphase I (4) anaphase II Microtubule is involved in the [CBSE'98] (1) cell division (2) muscle contraction (3) membrane architecture (4) DNA recognition A bacterium divides every 35 minutes. If a culture containing 105 cells per ml is grown for 175 minutes, what will be the cell concentration per ml after 175 minutes? [CBSE'98] (1) 5 × 105cells (2) 35 × 105cells (3) 32 × 105cells (4) 175 × 105cells The shape of chromosomes is usually observed at [AMU'98] (1) metaphase-I of meiosis (2) anaphase-I of meiosis (3) metaphase of mitosis (4) anaphase of mitosis Phragmoplast is the precursor of [BHU'98] (1) chloroplast (2) chromoplast (3) cell plate (4) leucoplast Decision of G0-phase occurs [AMU'98] (1) towards the end of G1-phase (2) before the G1-phase (3) at the end of telophase (4) towards the end of cytokinesis

CELL CYCLE AND CELL DIVISION 20.

21.

22.

23.

24.

25.

26.

27.

28.

29.

30.

31.

32.

33.

Chromatin fibres are observed only in the [CBSE'98] (1) prophase (2) metaphase (3) telophase (4) interphase How many meiotic divisions are required to produce 100 pollen grains ? [AFMC'99] (1) 25 (2) 50 (3) 100 (4) 125 At which phase of meiosis are there two cells, each with sister chromatids aligned at the spindle equator [Pune CET'98; BHU'99] (1) Anaphase II (2) Metaphase II (3) Metaphase I (4) Anaphase I Lateral loops of lampbrush chromosomes are thin at the [AMU'99] (1) middle (2) end (3) some places (4) beginning Which phases of cell division is arrested in oogonia of vertebrate ? [CBSE'99] (1) Anaphase II (2) Interphase (3) Diplotene (4) Both prophase I and II The correct sequence of cell cycle is [AMU'01] (1) S, Gl, G2, M (2) S, M, Gl, G2 (3) Gl, S, G2, M (4) M, Gl, G2, S Which event involves in crossing over? [AMU'01] (1) Chromosomes thickening (2) Exchange of genetic material (3) Pairing of chromosomes (4) Addition of chromosomes The point at which crossing over occurs is called as [BHU'01] (1) chiasmata (2) centromere (3) chromosome (4) gene loci Synaptonemal complex is formed during [CBSE'01] (1) meiosis (2) amitosis (3) mitosis (4) cytokinesis Four daughter cells formed after meiosis are [PMT'01] (1) genetically similar (2) genetically different (3) anucleate (4) multinucleate Which cell division is found during cleavage? [Rajasthan PMT'01] (1) Amitosis (2) Mitosis (3) Closed mitosis (4) Meiosis During cell cycle, RNA and non-histone proteins are synthesised in [CPMT'02] (1) S-phase (2) G0-phase (3) G2-phase (4) M-phase Best material for the study of mitosis in laboratory is [CBSE'02] (1) anther (2) root tip (3) leaf tip (4) ovary In mitosis, duplication of chromosomes occurs during [BHU'02] (1) interphase (2) prophase (3) metaphase (4) telophase

437 34.

35.

36.

37.

38.

39.

40.

41.

42.

43.

44. 45.

Crossing over helps in [AFMC'02] (1) pure line selection (2) inducing mutation (3) inducing polyploidy (4) recombination between the genes During pachytene stage of meiosis, the chromosomes appear [BHU'02] (1) single stranded (2) four stranded (3) six stranded (4) eight stranded If a diploid cell is treated with colchicine then it becomes [CBSE'02] (1) triploid (2) tetraploid (3) diploid (4) monoploid The stage at which cytokinesis begins in plant cells is [CBSE'02] (1) anaphase (2) telophase (3) G0 phase (4) interphase Reorganisation of genetic material or genetic recombination occurs during [CBSE'02] (1) metamorphosis (2) organogenesis (3) mitosis (4) meiosis G0 phase is [AMU'03] ' '03] (1) phase after G2 (2) phase after M phase in which daughter cell enters new cell cycle (3) arrest of cell cycle on the onset of differentiation (4) all of the above Which of the following stage during meiosis is concerned with DNA replication? [AFMC'03] (1) Interphase (2) Prophase (3) Metaphase (4) Anaphase In meiosis division is [BHU'03] (1) Ist reductional and IInd equational (2) Ist equational and IInd reductional (3) both reductional (4) both equational Pairing of homologous chromosome occurs at which stage? [BHU'03] (1) Zygotene (2) Leptotene (3) Metaphase (4) Pachytene Karyokinesis differ from cytokinesis because it involves [PM PMT'03] (1) division of cytoplasm (2) division of the nucleus and cytoplasm (3) division of the nucleus (4) division of the cell L-shaped anaphasic chromosomes are [AMU'03] (1) acentric (2) isobrachial (3) dicentric (4) submetacentric In mitotic metaphase the limbs of the chromosomes occur [CBSE'03] (1) on the equator (2) in different directions (3) in divaricate condition (4) All the above

438 46.

47.

48.

49.

50. 51.

52.

53.

54.

55.

BIOLOGY In the somatic cell cycle [CBSE'04] (1) In G1 phase DNA content is double the amount of DNA present in the original cell (2) DNA replication takes place in S-phase (3) a short interphase is followed by a long mitotic phase (4) G2 phase follows mitotic phase Which one of the following precedes reformation of the nuclear envelope during M phase of the cell cycle? [CBSE'04] (1) Decondensation of chromosomes and reassembly of the nuclear lamina (2) Transcription of chromosomes and reassembly of the nuclear lamina (3) Formation of the contractile ring and formation of the phragmoplast (4) Formation of the contractile ring and transcription of chromosomes In which phase, proteins for spindle fibre formation are synthesised? [AMU'04] (1) G1-phase (2) G2-phase (3) S-phase (4) Anaphase Cells in G0-phase of cell cycle [WB-JEE'04] (1) exit cell cycle (2) enter cell cycle (3) suspend cell cycle (4) terminate cell cycle Meiosis can be observed in [AMU'04] (1) tapetal cells (2) megaspores (3) microspores (4) spore mother cells Significance of meiosis lies in [AMU'04] (1) reduction of chromosome number to one half (2) maintaining consistancy of chromosome number during sexual reproduction (3) production of genetic variability (4) all of the above If you are provided with root-tips of onion in your class and are asked to count the chromosomes, which of the following stages can you most conveniently look into? [CBSE'04] (1) Metaphase (2) Telophase (3) Anaphase (4) Prophase Which one occurs once in life cycle ? [AMU'04] (1) Replication of DNA (2) Replication of chromosomes (3) Meiosis (4) Mitosis It is very difficult to stop cell division when the cell has entered [CBSE'04] (1) G1-phase (2) G2-phase (3) S-phase (4) prophase In which stage of the cell cycle histone proteins synthesized in a eukaryotic cell? [CBSE'05] (1) During G2 stage of prophase (2) During S-phase (3) During entire prophase (4) During telophase

56.

57.

58.

59.

60.

61.

62.

63.

64.

65.

66.

67.

In mitosis nucleolus and nuclear membrane disappear at [BHU'05] (1) interphase (2) prophase (3) metaphate (4) telophase Among the following which one is longest phase in prophase of meiosis ? [AMU'05] (1) Leptotene (2) Zygotene (3) Pachytene (4) Diplotene In meiosis, the daughter cells are not similar to that of parent because of [AFMC'05] (1) crossing over (2) synapsis (3) both (1) and (2) (4) none of these Cytokinesis in plants takes place by the formation of [BHU'05] (1) sphaeroblasts (2) equatorial cell plate (3) idioblasts (4) cell budding Meiosis II performs [CBSE'06] (1) separation of sex chromosomes (2) synthesis of DNA and centromere (3) separation of homologous chromosomes (4) separation of chromatids Colchicine prevents the mitosis of cells at which of the following stage ? [AMU'06] (1) Anaphase (2) Metaphase (3) Prophase (4) Interphase If we ignore the effect of crossing over, how many different haploid cells arise by meiosis in a diploid cell having 2n = 12 ? [AFMC'06] (1) 8 (2) 16 (3) 32 (4) 64 Strasburger is famous for [AMU'06] (1) discovery of cell division (2) proposing the term nucleoplasm (3) proposing the term cytoplasm (4) all of these Spindle fibre is made up of [BHU'06] (1) tubulin (2) humulin (3) intermediate filament (4) flagellin Dinomitosis is characterised by [AMU'06] (1) intranuclear spindle (2) absence of spindle (3) absence of chromosome movement (4) All the above In bouquet stage the chromosomes converge at a point near [AMU'06] (1) Golgi apparatus (2) centrosome (3) middle of nucleus (4) roughly their middle In which of the following stage, the chromosome is single, thin and like long thread? [AMU'07] (1) Leptotene (2) Zygotene (3) Pachytene (4) Diakinesis

CELL CYCLE AND CELL DIVISION 68.

69.

70.

71.

72.

73.

74.

75.

Segregation of Mendelian factor (Aa) occurs during [CBSE'08] (1) diplotene (2) anaphase I (3) zygotene/pachytene (4) anaphase II The exchange of genetic material between chromatids of paired homologous chromosomes during first meiotic division is called [CBSE'08] (1) transformation (2) chiasmata (3) crossing over (4) synapsis Chiasmata are formed during meiosis [AMU'08] (1) before metaphase I (2) after metaphase I (3) during prophase II (4) during metaphase II When synapsis is complete all along the chromosome, the cell is said to have entered a stage called [AFMC'08] (1) zygotene (2) pachytene (3) diplotene (4) diakinesis Match List I and List II and select the correct answer using the code given below in the lists [AMU'08] List I List II (Phase of meiosis) (Event that occurs) A. Prophase I Crossing over occurs B. Metaphase I Sister chromatids migrate to opposite poles C. Anaphase I Homologous chromosome line up at equator in pairs (1) A, B and C are correct (2) A and B are correct, C is false (3) A is correct, B and C are false (4) A and C are correct, B is false Chromosome duplication without nuclear division refers to [AMU'08] (1) meiosis (2) mitosis (3) androgenesis (4) endomitosis The stage at which cleavage or cytokinesis begins in animal cells is [CBSE'08] (1) anaphase (2) telophase (3) G0 phase (4) interphase Given below is a schematic break-up of the phases / stages of cell cycle. A

B

C

Mitosis

439 76.

77.

78.

79.

80.

81.

82.

83.

Gl, G2 and S phases are seen in which phase of cell cycle? [AFMC'09] (1) metaphase (2) prophase (3) anaphase (4) interphase Genome is [CBSE'09] (1) genes of haploid set of chromosomes. (2) genes of diploid set of chromosomes. (3) a single chromosome (4) None of the above Given below is a schematic break-up of the phases / stages of cell cycle:

Which one of the following is the correct indication of the stage/phase in the cell cycle? [CBSE PMT 2009] (1) C - Karyokinesis (2) D - Synthetic phase (3) A - Cytokinesis (4) B - Metaphase Synapsis occurs between: [CBSE PMT 2009] (1) mRNA and ribosomes (2) spindle fibres and centromere (3) two homologous chromosomes (4) a male and a female gamete The non-sister chromatids twist around and exchange segments with each other during [Kerala PMT 2009] (1) diplotene (2) diakinesis (3) leptotene (4) pachytene At Gl stage which phenomenon takes place ? [AFMC'10] (1) DNA synthesis (2) RNA synthesis (3) Reverse transcription (4) All of the above During mitosis ER and nucleolus begin to disappear at [CBSE'10] (1) late prophase (2) early metaphase (3) late metaphase (4) early prophase Which stages of cell division do the following figures A and B represent respectively? [CBSE'10]

Interphase D

Which one of the following is the correct indication of the stage/phase in the cell cycle? [CBSE'09] (1). C - Karyokinesis (2) D - Synthetic phase (3) A - Cytokinesis (4) B - Metaphase

A

B

440

84.

85.

BIOLOGY Fig. A Fig. B (1) Metaphase Telophase (2) Telophase Metaphase (3) Late Anaphase Prophase (4) Prophase Anaphase During mitosis ER and nucleolus begin to disappear at: [CBSE PMT 2010] (1) late prophase (2) early metaphase (3) late metaphase (4) early prophase Which stages of cell division do the following figures A and B represent respectively? [CBSE PMT 2010]

91.

92.

93.

86.

87.

88.

89.

90.

Fig. A Fig. B (1) Metaphase Telophase (2) Telophase Metaphase (3) Late Anaphase Prophase (4) Prophase Anaphase During meiosis I, the bivalent chromosomes clearly appear as tetrads during [Kerala PMT 2010] (1) diakinesis (2) diplotene (3) leptotene (4) pachytene Many cells function properly and divide mitotically even though they do not have [AIIMS'11] (1) plasma membrane (2) cytoskeleton (3) mitochondria (4) plastids Select the correct option with respect to mitosis. [CBSE PMT 2011] (1) Chromatids separate but remain in the centre of the cell in anaphase. (2) Chromatids start moving towards opposite poles in telophase. (3) Golgi complex and endoplasmic reticulum are still visible at the end of prophase. (4) Chromosomes move to the spindle equator and get aligned along equatorial plate in metaphase At metaphase, chromosomes are attached to the spindle fibres by their: [CBSE PMT 2011M] (1) satellites (2) secondary constrictions (3) kinetochores (4) centromere Colchicine prevents the mitosis of cells at which of the following stage ? [AFMC 2011] (1) Anaphase (2) Metaphase (3) Prophase (4) Interphase

94.

95.

96.

97.

From a diploid condition of 2n, with condition can arise’ due to non disjunction of chromosome [AFMC 2011] (1) 3n (2) 5n (3) 2n + 1 (4) n Which one of the following precedes re-formation of the nuclear envelope during M-phase of the cell cycle? [JIPMER-2011] (1) Decondensation from chromosome and reassembly of the nuclear lamina (2) Transcription from chromosome and reassembly of the nuclear lamina (3) Formation of the contractile ring and formation of the phragmoplast (4) Formation of the contractile ring and transcription from chromosomes Select the correct match. [Kerala PMT 2011] (1) S phase - DNA replication (2) Zygotene - Synapsis (3) Diplotene - Crossing over (4) Meiosis - Both haploid and diploid cells (E) Gap 2 phase - Quiescent state (1) A & B (2) C & D (3) C & E (4) A, C & E The stage between two meiotic divisions is called [Kerala PMT 2011] (1) interphase (2) cytokinesis (3) interkinesis (4) karyokinesis During gamete formation, the enzyme recombinase participates during [CBSE'2012] (1) Metaphase - I (2) Anaphase - II (3) Prophase - I (4) Prophase - II Given below is the representation of a certain event at a particular stage of a type of cell division. Which is this stage? [CBSE'2012]

(1) Prophase I during meiosis (2) Prophase II during meiosis (3) Prophase of Mitosis (4) Both prophase and metaphase of mitosis Identify the meiotic stage in which the homologous chromosomes separate while the sister chromatids remain associated at their centromeres? [CBSE'2012] (1) Metaphase I (2) Metaphase II (3) Anaphase I (4) Anaphase II

CELL CYCLE AND CELL DIVISION 98.

99.

100.

101. 102. 103.

104.

105.

Which chromosome may lost during cell division? [AIIMS 2012] (1) Giant chromosome (2) Acentric chromosome (3) Polycentric chromosome (4) Telocentric chromosome Assertion : Interphase is resting stage. Reason : The interphase cell is metabolically inactive. [AIIMS 2012] (1) If both Assertion and Reason are correct and Reason is the correct explanation of Assertion. (2) If both Assertion and Reason are correct, but Reason is not the correct explanation of Assertion. (3) If Assertion is correct but Reason is incorrect. (4) If Assertion is incorrect but Reason is correct. G 1, G 2 and S phases are seen in which phase of cell cycle? [AFMC 2012] (1) Metaphase (2) Prophase (3) Anaphase (4) Interphase. Miotic spindle have main protein [JIPMER-2012] (1) tubulin (2) myosin (3) tropomyosin (4) dynein Crossing over occurs in [JIPMER-2012] (1) zygotene (2) leptotene (3) pachytene (4) diplotene Find the correctly matched pairs and choose the correct option. [Kerala PMT 2012] A. Leptotene - The chromosomes become invisible B. Zygotene - Pairing of homologous chromosomes C. Pachytene - Dissolution of the complex synaptonemal takes place D. Diplotene - Bivalent chromosomes appear as tetrads E. Diakinesis - Terminalization of chiasmata takes place (1) A and B are correct (2) B and D are correct (3) B and E are correct (4) B and C are correct Which of the following events are not characteristic features of telophase? [Kerala PMT 2012] A. Chromosome material condenses to form compact mitotic chromosomes. B. Nucleolus, Golgi complex and ER reform C. Nuclear envelope assembles around the chromosome clusters. D. Centromeres split and chromatids separate. E. Chromosomes cluster at opposite, spindle poles and their identity as discrete element is lost. (1) A, B and D only (2) A and D only (3) B and C only (4) C, D and E only A stage in cell division is shown in the figure. Select the answer which gives correct identification of the stage with its characteristics. [AIMPT 2013]

441

(1) Late anaphase

106.

107.

108.

109.

Chromosomes move away from equatorial plate, Golgi complex not present (2) Cytokinesis Cell plate formed, mitochondria distributed between two daughter cells (3) Telophase Endoplasmic reticulum and nucleolus not reformed yet (4) Telophase Nuclear envelop reforms, golgi complex reforms The complex formed by a pair of synapsed homologous chromosomes is called [AIMPT 2013] (1) Kinetochore (2) Bivalent (3) Axoneme (4) Equatorial plate During the metaphase stage of mitosis spindle fibres attach to chromosomes at [NEET Kar. 2013] (1) Centromere (2) Kinetochore (3) Both centromere and kinetochore (4) Centromere, kinetochore and areas adjoining centromere During meiosis I, the chromosomes start pairing at [NEET Kar. 2013] (1) Leptotene (2) Zygotene (3) Pachytene (4) Diplotene A stage of mitosis is shown in the diagram. Which stage is it and what are its characteristics? [NEET Kar. 2013]

(1) Late prophase – chromosomes move to spindle equator (2) Metaphase – spindle fibres attached to kinetochores, centromeres split and chromatids separate (3) Metaphase – chromosomes moved to spindle equator chromosomes made up of two sister chromatids (4) Anaphase – centromeres split and chromatids separate and start moving away

442

BIOLOGY

110. The stage of meiosis where centromere separate [AIIMS 2013] (1) metaphase I

(2) metaphase II

(3) anaphase I

(4) anaphase II

111. Which of the following events takes place during anaphase stage of mitosis? [Kerala PMT 2013] I.

Spindle fibres attach to kinetochores of chromosomes.

II.

Centromeres split and chromatids separate.

III. Chromatids move to opposite poles. IV. Nucleolus, Golgi complex and ER reform. (1) I and II only

(2) II and III only

(3) III and IV

(4) I and IV only

112. During which phase(s) of cell cycle, amount of DNA in a cell remains at 4C level if the initial amount is denoted as 2C? [AIPMT - 2014] (1) G0 and G1

(2) G1 and S

(3) Only G2

(4) G2 and M

113. In ‘S’ phase of the cell cycle:

[AIPMT 2014]

(1) Amount of DNA doubles in each cell. (2) Amount of DNA remains same in each cell. (3) Chromosome number is increased. (4) Amount of DNA is reduced to half in each cell. 114. The enzyme recombinase is required at which stage of meiosis: [AIPMT 2014] (1) Pachytene

(2) Zygotene

(3) Diplotene

(4) Diakinesis

115. Select the correct option : I A "Synapsis aligns homologous chromosomes" B "Synthesis of RNA and protein" C "Action of enzyme recombinase" D "Centromeres do not separate but chromatids move towards opposite poles"

[AIPMT 2015] (i)

II Anaphase-II

(ii)

Zygotene

(iii)

G2-phase

(iv)

Anaphase-I

(v)

Pachytene

A B C D (1) (ii) (iii) (v) (iv) (2) (i) (ii) (v) (iv) (3) (ii) (iii) (iv) (v) (4) (ii) (i) (iii) (iv) 116. A somatic cell that has just completed the S phase of its cell cycle, as compared to gamete of the same species, has: [AIPMT 2015] (1) same number of chromosomes but twice the amount of DNA (2) twice the number of chromosomes and four times the amount of DNA (3) four times the number of chromosomes and twice the amount of DNA (4) twice the number of chromosomes and twice the amount of DNA 117. In human females, meiosis-II is not complete until? [Re-Test AIPMT 2015] (1) fertilization (2) uterine implantation (3) birth (4) puberty

CELL CYCLE AND CELL DIVISION

443

EXERCISE - 3 | Test Yourself 1.

2.

3.

4.

5.

6.

7.

8.

9.

The number of DNA in chromosome at G2 stage of cell cycle is (1) one (2) two (3) four (4) eight “G0” state of cells in eukaryotic cell cycle denotes (1) check point before entering the next phase (2) pausing in the middle of a cycle to cope with a temporary delay (3) death of a cell (4) exit of cells from cell cycle G2 phase of mitosis takes (1) 50% time of cell cycle (2) 25 to 33% time of cell cycle (3) 12 to 16% time of cell cycle (4) 4% time of cell cycle In eukaryotic cell cycle, cell fusion experiments show that (1) when an S-phase cell is fused with a G1-phase cell, G1-phase cell is stimulated to synthesize DNA (2) when an S-phase cell is fused with a G1-phase cell (3) when a G1-phase cell is fused with a G1 phase cell, DNA synthesis is induced in both G1 and G2 phase cells (4) when a G1-phase cell is fused with an M-phase Cell division can not be stopped in which phase of the cell cycle ? (1) G1-phase (2) G2 phase (3) S-phase (4) Prophase Chromosome number can be doubled by using which of the following? (1) Indole acetic acid (2) GA (3) Zeatin (4) Colchicine Interphase nucleus is enclosed by (1) non-porous, nuclear membrane (2) porous, double layered nuclear membrane (3) non-porous, double layered, discontinuous nuclear membrane (4) a single porous unit membrane Most cytogenic activities occur during (1) interphase (2) telophase (3) prophase (4) anaphase Mitosis occurs in (1) haploid individuals (2) diploid individuals (3) Both (1) and (2) (4) in bacteria only

10.

11.

12.

13.

14.

15.

16.

17.

Which is not the character of mitosis? (1) Leptotene (2) Zygotene (3) Pachytene (4) All of the above Mitosis is the process by which eukaryotic cells (1) expose the genes for protein synthesis (2) become specialized in structure and function (3) multiply (4) grow Chromosome start separating at which stage of mitosis (1) Early metaphase (2) Late metaphase (3) Early anaphase (4) Early telophase Period of active mitosis ranges from (1) 10 minutes to a few hours (2) a few hours to a one day (3) one day to a week (4) less than a minute Anastral mitosis is found in (1) animals (2) higher plants (3) bacteria (4) cyanobacteria What is the correct sequence of the steps given here ? Also work out the process depicted in the steps ? I. Homologous chromosomes move towards opposite poles of the cell; chromatids do not separate. II. Chromosomes gather at the two poles of the cell and the nuclear membranes reform. III. Homologous chromosomes pair and exchange segments. IV. The chromosomes align on a central plate. V. The haploid cells separate completely. (1) The correct sequence is III→IV→I→II→V and the process is meiosis-I (2) The correct sequence is II→I→V→IV→III and the process is mitosis (3) The correct sequence is IV→I→III→II→V and the process is meiosis-I (4) The correct sequence is II→V→IV→I→II and the process is mitosis-I A cell plate is laid down during (1) cytokinesis (2) karyokinesis (3) interphase (4) None of these Congression is a phenomenon of (1) movement of sister chromatids towards the poles (2) pairing of homologous chromosomes (3) separation of paired chromosomes (4) bringing the chromosomes on equator of spindle apparatus

444 18.

19.

20. 21.

22.

23.

24.

25. 26.

27.

28.

BIOLOGY The major event that occurs during the anaphase of mitosis, which brings about the equal distribution of chromosomes is (1) replication of the genetic material (2) splitting of the chromatids (3) splitting of the centromeres (4) condensation of the chromatin What type of cell division takes place in the functional megaspore initially in angiosperms ? (1) Homotypic without cytokinesis (2) Reductional without cytokinesis (3) Somatic followed by cytokinesis (4) Meiotic followed by cytokinesis The anaphase promoting complex is activated by (1) M cdk cyclin (2) G1 cdk cyclin (3) S cdk cyclin (4) transcription factor An egg cell has 5 pico gram of DNA in its nucleus. How much amount of DNA will be at the end of G2-phase of mitosis? (1) 2.5 pico gram (2) 5 pico gram (3) 5 g (4) 20 pico gram Cleavage is a unique form of mitotic cell division in which (1) there is no growth of cells (2) the nucleus does not participate (3) no spindle develops to guide the cells (4) the plasma membranes of daughter cells do not separate A plant cell has 12 chromosomes at the end of mitosis. How many chromosomes would it have in the G2-phase of its next cell cycle? (1) 6 (2) 8 (3) 12 (4) 24 In animal cells, cytokinesis involves (1) the separation of sister chromatids (2) the contraction of the contractile ring of micro filament (3) depolymerisation of kinetochore microtubules (4) a protein kinase that phosphorylates other enzymes Which of the following serves as mitotic spindle poison ? (1) Ca2+ (2) Mg2+ (3) Tubulin (4) Colchicine The two chromatids of a metaphase chromosome represent (1) replicated chromosomes to be separated at anaphase (2) homologous chromosomes of a diploid set (3) non-homologous chromosomes joined at the centromere (4) maternal and paternal chromosomes joined at the centromere The proteins involved in the movement of chromosomes towards the poles during cell division are (1) actin (2) myosin (3) tubulin (4) elastin In meiosis-I, bivalent is an association of (1) four chromatids and four centromeres (2) two chromatids and one centromere (3) two chromatids and one centromere (4) four chromatids and two centromeres

29.

30.

31.

32.

33.

34.

35.

36.

37.

38.

There are three genes a, b, c. Percentage of crossing over between a and b is 20%, b and c is 28% and a and c is 8%. What is the sequence of genes on chromosome? (1) b, a, c (2) a, b, c (3) a, c, b (4) None of these Characteristic of meiosis is (1) two nuclear and two chromosome divisions (2) two nuclear and one chromosome division (3) one nuclear and two chromosome divisions (4) one nuclear and one chromosome division The number of chromosomes becomes half in (1) anaphase-I (2) anaphase-II (3) telophase-I (4) telophase-II Arrange the following events of meiosis in the correct sequence. (a) Terminalisation (b) Crossing over (c) Synapsis (d) Disjunction of genomes The correct sequence is (1) d, c, b, a (2) c, b, a, d (3) b, a, d, c (4) a, d, c, b Which type of chromosomes segregate when a cell undergoes meiosis? (1) Homologous chromosomes (2) Non-homologous chromosomes (3) Both (1) and (2) (4) centric and acentric chromosomes During cell division, sometimes there will be failure of separation of sister chromatids. This event is called (1) interference (2) complementation (3) non-disjunction (4) coincidence When number of chromosomes is already reduced to half in the first reductional division of meiosis, where is the necessity of second meiotic division? (1) The division is required for the formation of four gametes (2) Division ensures equal distribution of haploid chromosomes (3) Division ensures equal distribution of genes on chromosomes (4) Division is required for segregation of replicated chromosomes Alleles of different genes that on the same chromosomes may occasionally separated by a phenomenon known as (1) pleiotropy (2) epistasis (3) continuous variation (4) crossing over Meiosis in AaBb will produce gametes (1) AB, aB, Ab, ab (2) AB, ab (3) Aa, bb (4) Aa, Bb Condensation of chromosomes occurs in (1) prophase I (2) prophase II (3) anaphase (4) metaphase

CELL CYCLE AND CELL DIVISION 39. 40. 41.

42.

43.

44.

45.

46.

47.

48.

49.

50.

Which of the following stage is affected by colchicum? (1) Metaphase (2) Prophase (3) Interphase (4) Anaphase Which type of cell division occurs in the gonads? (1) Mitosis only (2) Meiosis (3) Both (1) and (2) (4) Amitosis and meiosis How many ATP is required during anaphase to move chromosomes from equator to the poles? (1) 38 ATP (2) 5 ATP (3) 30 ATP (4) 76 ATP An anaphase chromosome contains (1) 1 DNA molecule (2) 3 DNA molecule (3) 2 DNA molecule (4) 4 DNA molecule During cell division, sometimes there will be failure of separation of sister chromatids. This event is called (1) interference (2) complementation (3) concidence (4) non-disjunction A cell in prophase of mitosis can be distinguished from a cell in prohase-I of meiosis by (1) The presence of only half as many chromosomes in the meiotic cell (2) The formation of tetrads in the meiotic cell (3) The presence of twice as many chromosomes in the meiotic cell (4) None of the above The number of chromatids in a chromosome at anaphase is (1) 2 in mitosis and 1 in meiosis (2) 1 in mitosis and 2 in meiosis (3) 2 each in mitosis and meiosis (4) 2 in mitosis and 4 in meiosis Cell division in blue-green algae is more or less similar to that in (1) red algae (2) green algae (3) brown algae (4) bacteria “Endomitosis” refers to (1) division of nucleus without chromosomal division (2) division of chromosome without nuclear division (3) division of cytoplasm (4) none of the above Which of the following will show simple cell division? (1) Microspore mother cells (2) Megaspore mother cells (3) Archesporial cells (4) All the above In animal cell cytokinesis takes place by (1) cell furrow method (2) cell plate method (3) both (1) and (2) (4) no cytokinesis takes place In cancer cells (1) meiosis takes place (2) mitosis takes place (3) sometimes meiosis and sometimes mitosis take place (4) cell division stops

445 51.

52.

53.

54.

55.

56.

57.

58.

59.

60.

61.

62.

Which one of the following forms the spindle apparatus during cell division? (1) Chromosome (2) Centrosome (3) Ribosome (4) Chondriosome During cell division in apical meristem nuclear membrane reappears in (1) interphase (2) telophase (3) prophase (4) S phase Which of the following cell division is found in prokaryotic cells? (1) Mitosis (2) Meiosis (3) Amitosis (4) All the above If nucleus represents its large size in proportion to cytoplasm of cell, it indicates that (1) cell is dying (2) the nucleolus is in resting phase (3) the nucleus has entered S-phase of interphase (4) cell is about to die An acrocentric chromosome at metaphase will be (1) condensed and lie near the equator (2) irregularly shaped and lie at one of the poles (3) condensed and lie at poles (4) coiled and get atached to spindle fibre Which is not true for anaphase? (1) Golgi body and ER are reformed (2) Chromosomes move to opposite poles (3) Spindle poles move farther apart (4) Centromeres split and chromatids separate The role of meiosis is (1) formation of gametes (2) bringing haplophase (3) bringing diplophase (4) completing life cycle For viewing diakinesis which one of the folowing would be a suitable material (1) Onion root tip (2) Leaf of Dichanthium (3) Rat tail (4) Flower bud Bivalents in meiosis are (1) tetrad (2) pairs of non-homologous chromosomes (3) pairs of several chromatids (4) pairs of homozygous chromosomes Repulsion of homologous chromosomes takes place in (1) zygotene (2) leptotene (3) diakinesis (4) diplotene The spindle fibre contracts in (1) metaphase I (2) anaphase II (3) prophase II (4) telophase II Recombination of genes occur at (1) prophase in mitosis (2) prophase I in meiosis (3) prophase II in meiosis (4) metaphase II in meiosis

446 63.

64.

65.

66.

67.

68.

69.

70.

71.

BIOLOGY The second division in meiosis is called (1) equational division (2) reduction division (3) multiplied division (4) None of the above If at the end of meiosis, the 4 daughter cells have 4 chromosomes, how many chromosomes were in the mother cell? (1) 8 (2) 16 (3) 2 (4) 4 The number of chromosome groups at the equatorial plate in metaphase-I of meiosis in a plant with 2n = 50 shall be (1) 50 (2) 25 (3) 30 (4) 100 Terminalization occurs in which stage (1) Pachytene (2) Diplotene (3) Zygotene (4) Diakinesis If a cell has a chromosome number after first meiosis equal to 48. The chromosome number in the daughter cells after the completion of meiosis will be (1) 48 (2) 24 (3) 12 (4) 36 If for a species 2n = 16, then during Ist prophase and IInd prophase of meiotic division of a cell, how many tetrads and diads will be formed (1) 4 and 4 (2) 8 and 4 (3) 8 and 8 (4) 4 and 8 Mitotic index means (1) rate of mitotic division (2) ratio of mitotic and meiotic division (3) ratio of dividing and non-dividing cells (4) none of the above In which of the following meiosis takes place? (1) Pollen grains (2) Pollen tube (3) Pollen mother cells (4) Generative cells Which of the following structure form cell plate at the end of nuclear division ?

72.

73.

74.

75.

76.

77.

78.

(1) Microtubules (2) Vesicles (3) Endoplasmic reticulum (4) Golgi body The force responsible for the terminalization at the time of cell division is (1) chemostatic (2) galvanostatic (3) electrostatic (4) none of the above In an organism, if the normal diploid number of chromosomes is 8, how many chromatids are present in each daughter cell at the end of meiosis I (1) 2 (2) 4 (3) 8 (4) 16 The study of chromosomes at meiotic diplotene shows that (1) the intimately paired chromosomes repel each other and begin to separate (2) the pairing of homologous chromosomes which had initiated in the earlier stage is completed (3) the homologous chromosomes remain united by chiasmata (4) none of above The points at which crossing over has taken place between homologous chromosomes are called (1) protein axis (2) synaptonemal complexes (3) chiasmata (4) centromeres How many meiotic division would be required to produce 101 female gametophytes in an angiosperm? (1) 101 (2) 26 (3) 127 (4) None of these Crossing over occurs (1) single strand stage (2) two strand stage (3) four strand stage (4) eight strand stage Recombination is involved in the process of (1) cytokinesis (2) spindle formation (3) crossing over (4) chromosome duplication

CELL CYCLE AND CELL DIVISION

447

ANSWER KEY EXERCISE 1 : NCERT BASED QUESTIONS 1. 6. 11. 16 . 21. 26.

(4) (1) (4) (1) (1) (2)

2. 7. 12. 17. 22. 27.

(3) (2) (1) (3) (2) (1)

3. 8. 13. 18. 23. 28.

(1) (4) (4) (2) (2) (1)

4. 9. 14. 19. 24. 29.

(1) (2) (1) (4) (1) (1)

5. 10. 15. 20. 25. 30.

(3) (3) (2) (2) (3) (4)

3.

(3)

4.

5.

(3)

Cell division can not be stopped after S-phase. The S-phase is the synthesis phase, in which the cell synthesises a replica of its genome, i.e., DNA replication occurs.

6.

(4)

7.

8.

(1)

Interphase is the period between the end of one cell division to the beginning of next cell division. During this phase, the cell is metabolically very active and prepares itself for the division.

9.

(3)

10.

(4)

Leptotene, zygotene, pachytene, diplotene and diakinesis all are successive stages of meiosis.

11.

(3)

12.

16.

(1)

During cytokinesis in plant cells, spindle fibres do not degenerate and forms phragmoplast and cell plate.

17.

(4)

18.

(3)

Anaphase is characterised by spliting of the centromeres and separation of chromatids. Chromatids move to opposite poles from the equatorial plates.

19. 24.

(1) (2)

20. 25.

27.

(3)

The spindle apparatus formed during cell division is composed of microtubules radiating in all directions. The microtubules are chemically composed of tubulin protein (α-tubulin, β-tubulin).

28.

(4)

29.

(1)

33.

(1)

34.

(3)

35.

(4)

The first meiotic division leads to reduction of chromosome number to half and the second meiotic division segregate the replicated chromosomes.

36.

(4)

37.

39.

(1)

Colchicine is obtained from Colchicum autumnale plant, which inhibits the formation of spindle fibers in metaphase.

EXERCISE 2 : WINDOW TO COMPETITIVE EXAMS 1. 6. 11. 16. 21. 26. 31. 36. 41. 46. 51. 56. 61. 66. 71. 76. 81. 86. 91. 97. 102. 107. 112. 117.

(1) (1) (2) (3) (1) (2) (3) (2) (1) (2) (4) (2) (2) (2) (2) (4) (2) (4) (3) (1) (3) (2) (3) (1)

2. 7. 12. 17. 22. 27. 32. 37. 42. 47. 52. 57. 62. 67. 72. 77. 82 . 87. 92. 98. 103. 108. 113.

(2) (3) (3) (3) (2) (1) (2) (1) (1) (2) (1) (3) (4) (1) (3) (1) (4) (4) (2) (2) (3) (2) (1)

3. 8. 13. 18. 23. 28. 33. 38. 43 48. 53. 58. 63. 68. 73 . 78. 83. 88. 93. 99. 104. 109. 114.

(2) (1) (1) (3) (4) (1) (1) (4) (3) (2) (3) (1) (4) (2) (2) (2) (3) (4) (1) (3) (2) (3) (1)

4. 9. 14. 19. 24. 29. 34. 39. 44. 49. 54. 59. 64. 69. 74. 79. 84. 89. 94. 100. 105. 110. 115.

(3) (4) (4) (2) (3) (2) (4) (3) (4) (3) (3) (2) (1) (3) (1) (3) (4) (3) (3) (3) (4) (4) (1)

5. 10. 15. 20. 25. 30. 35. 40. 45. 50. 55. 60. 65. 70. 75. 80. 85. 90. 95. 101. 106. 111. 116.

(2) (3) (1) (4) (3) (3) (2) (1) (2) (4) (2) (4) (2) (1) (2) (4) (3) (2) (3) (1) (2) (2) (2)

EXERCISE 3 : TEST YOURSELF 1.

2.

(2)

(4)

The duplication of DNA takes place in ‘S’ stage of interphase after that cell reaches in G2 phase. That is why the strand of DNA in G2 phase will be two. When cells are not to divide after G1 phase and start undergoing differentiation into specific types of cells such cells are said to be in G0 phase/G0 state.

(2)

(2)

(3)

(1) (4)

(1)

13.

21. 26.

30.

38.

(1)

(4) (1)

(2)

14.

22.

31.

(2)

(1)

(1)

15.

23.

32.

(1)

(4)

(2)

(1)

448

BIOLOGY

40.

(3)

Mitosis and meiosis both type of cell division occurs in gonads. Mitosis during growth and development and meiosis during gametogenesis.

60.

(4)

In meiosis, crossing over takes place in pachytene, after that chromosome get repel in diplotene.

61.

(2)

62.

41. 46.

(3) (4)

42. 47.

66.

(4)

Diakinesis is the last stage of prophase-I in which cross over separates called terminalization.

50.

(2)

Due to rapid mitotic divisions hypertrophy takes place in cancerous cells.

67.

(1)

68.

51. 56.

(2) (1)

52.

70.

(3)

Pollen grain formed from pollen mother cells by meiosis.

57.

(2)

The most important role of meiosis is to maintain haploid phase.

71.

(2)

72.

73.

(3)

58.

(4)

59.

(1)

Because each chromosome bears two chromatids and at the end of meiosis-I chromosome number becomes halved i.e. 4 and number of chromatids are 4 × 2 = 8.

74.

(3)

75.

(1) (2)

(2)

43. 48.

53.

(4) (3)

(3)

44. 49.

54.

(2) (1)

(3)

45.

55.

(2)

(1)

Bivalent formation occurs in pachytene of meiosis. Two chromatids of homologous chromosome (Bivalent) later on forms a cross and then show a tetravalent or tetrad stage.

(2)

(3)

63.

69.

(1)

64.

(1)

65.

(2)

(3)

(3)

(3)

76.

(1)

77.

(3)

78.

(3)

11

Chapter

Transport in Plants At a Glance

While going through the chapter pay special attention to the following – Terms and definitions – 1. Diffusion pressure 3. Reverse osmosis 5. Pressure potential 7. Turgor pressure Differences between – 1. Transpiration & evaporation Flow Charts – 1. Types of membranes

2. 4. 6. 8.

Membrane permeability Solute potential Casparian strips Scotoactive stomata

 

Introduction Means of transport  Diffusion 

 

2.

Open & closed stomata



Types of transpiration.

  





Plants lack both interstitial fluid as well as a regular circulation system. Even then they have to move (transport) various types of substances (gases, minerals, water, hormones, photosynthates and organic solutes) not only to short distance (from one cell to another or from one tissue to another) but also to very long distances such as water from roots to tops of plants or photosynthates from leaves to tips of roots. Substances move over short distances through diffusion and active transport supplemented by cytoplasmic streaming. The movement over longer distances occur through the vascular system, the xylem & the phloem. Such type of movement is called translocation.



One of the important aspect of translocation is its direction. In rooted plants, transport of water & minerals through xylem is unidirectional (which occurs from roots to stems), and transport of organic compounds & mineral nutrients is multidirectional. Organic compounds (synthesized in leaves) are exported to all other parts including every living cell, growing points, fruits and storage organs. From storage organ they are later re-exported. Mineral nutrients are primarily picked up by roots. They are passed out upwardly to leaves, stem and growing regions through vascular system (xylem and phloem).



Senescent organs and leaves pass out most of their nutrients, especially the minerals, before falling down from the plant.



Plant hormones and other chemical stimuli are transported in very small amounts. Therefore, a complex traffic of materials is going on in flowering plants, some moving to different directions, some passing out in polarized manner, with most organs, receiving some substances and giving out some others.



Active transport

Comparison of different transport processes

Plant water relations Water potential



2.

Facilitated diffusion (passive symports & antiports)

Osmosis

Plasmolysis Imbibition

Long distance transport of water  How do plants absorb water 

Water movement up a plant  

 

Transpiration pull

Transpiration Uptake & transport of mineral ions  Uptake of mineral ions 



Root pressure

Translocation of mineral ions

Phloem Transport

450

BIOLOGY Connecting Concepts

MEANS OF TRANSPORT

Diffusion pressure of pure water is maximum. Its value at 20ºC is 1336.40 Diffusion  Diffusion is passive and may be from one part of the cell to the other, or from cell to cell, atm.  DPD (Diffusion pressure deficit) is the reduction on the diffusion pressure of water over its pure state. DPD is the  water absorbing capacity of a solution. Therefore, DPD can also be called as suction pressure (SP).



It is related with osmotic pressure (OP), turgor pressure (TP) & wall  pressure (WP), in the following ways. DPD/SP = OP –WP



but, WP = TP So DPD = OP – TP



In fully turgid cells, turgor pressure is equal to osmotic pressure. Hence  diffusion pressure deficit is zero in such case. OP = TP (in turgid cell) DPD = 0 In fully plasmolysed cells, the value of TP becomes zero due to decrease in TP & increase of OP.



or over short distances, like, from the inter-cellular spaces of the leaf to the outside. No energy expenditure takes place. Diffusion is a random movement of individual molecules from a region of higher concentration to a region of lower concentration. It is a slow process and independent of living system. Larger the difference in concentration, more rapid is the flow of molecules. Uptake and distribution of water, gases and solutes occur in plants as a result of diffusion. Diffusion is common in gases and liquids, but diffusion in solids rather than of solids is more likely. E.g. diffusion of CO2 from atmosphere to leaves.

Diffusion rates are affected by concentration gradient, membrane permeability, temperature and pressure. Diffusion pressure, DP (term coined by Meyer, 1938), is the pressure exerted by the tendency of the particles to diffuse from the area of higher concentration to the area of their lower concentration. Diffusion pressure is directly proportional to the concentration of particles of the diffusing substance and temperature. The extent to which a membrane permits or restricts the movement of a substance is called membrane permeability. It depends on the membrane composition and chemical nature of the solute.

TP = 0 So, SP/DPD = OP (in plasmolysed cell) Thus, it is obvious DPD of plant cell is not directly proportional to their OP & concentration of cell sap but depends on both OP & TP.

Flow Chart 11.1 Types of membranes

TRANSPORT IN PLANTS

451

Facilitated Diffusion     



 

Rate of diffusion depends on the size of substances; the smaller substances diffuse faster. Diffusion of substance also depends on its solubility in lipids. Lipid soluble substances diffuse faster. The substance that have a hydrophobic moiety, find it difficult to pass through membrane. The movement of such molecules are facilitate, for which proteins provide site at which such molecule cross membrane. This is called as facilitated diffusion. In facilitated diffusion the concentration gradient must be present. The special proteins that help in movement of substances across the membranes do not require expenditure of ATP energy. Facilitated diffusion is sensitive to inhibitors which reacts with protein side chains. Facilitated diffusion cannot cause net transport of molecules from a low to a high concentration – this would require input of energy. Transport rate reaches a maximum when all of the protein transporters are being used (saturation). Facilitated diffusion is very specific, it allows cell to select substances for uptake. Some protein channels present on membrane are always open; others can be controlled. The porins are proteins that form huge pores in the outer membranes of the plastids, mitochondria and some bacteria. Fig. 11.1 shows an extra cellular molecule bound to the transport protein; the transport protein then rotates and releases the molecule inside the cell. Water channels are made up of eight different types of aquaporins, which are membrane protein for passive transport of water soluble substance.

Fig. 11.1 Facilitated diffusion

Passive symports and antiports  Few transport proteins or carriers proteins permit diffusion only if two types of molecules move together.(fig. 11.2)  In symport, both molecules cross the membrane in the same direction.  In antiport, both molecules cross the membrane in opposite directions.  In uniport, molecule moves across a membrane independent of other molecule.

Fig. 11.2 Facilitated diffusion

Check Point Give a scientific term for the following. (i) The movement of molecules from region of their higher concentration to the region of lower concentration. (ii) The extent to which a membrane permits or restricts the movement of a substance. (iii) Type of membranes allow selective passage of solutes along with solvent through them using different mechanism. (iv) The movement over longer distances occur through the xylem & phloem. (v) The reduction on the diffusion pressure of water over its pure state. (vi) Both the molecules cross the membrane in opposite direction. (vii) Proteins that form huge pores in the outer membranes of the plastids, mitochondria & some bacteria.

452

BIOLOGY Active Transport 

Active transport uses energy to pump molecules against a concentration gradient.



Active transport is carried out by membrane bound proteins. Hence, different proteins in the membrane play a major role in both active as well as passive transport.



Cells undergoing active transport bear abundant mitochondria to provide ATP, needed to power active transport. Pumps are protein which can transports the substances.



Active transport shows uphill transport because in this case movement can occur from lower to higher concentration.



Carrier proteins are highly specific like enzymes for substances to be carried across the membrane.



Inhibitors can inhibit the process by reacting with protein side chain.



When all the protein carriers are in use or saturated with substances to be carried, transport rate reaches its maximum. Table 11.1 : Comparison of different transport mechanism Property

Simple diffusion

Facilitated transport

Active transport

1. Requires special membrane proteins

No

Yes

Yes

2. 3. 4. 5.

No No No No

Yes Yes No No

Yes Yes Yes Yes

Highly selective Transport saturates Uphill transport Requires ATP energy

PLANT WATER RELATION 

Water is essential for all physiological activities of plants.



Water acts as an excellent solvent and help in the uptake and distribution of mineral nutrients and other solutes.



The protoplasm of the cells is nothing but water in which different molecules are dissolved and (several particles) suspended. A watermelon has over 92 percent water; most herbaceous plants have only about 10 to 15 percent of its fresh weight as dry matter. Of course, distribution of water within a plant varies – woody parts have relatively very little water, while soft parts mostly contain water. A seed may appear dry but it still has water – otherwise it would not be alive and respiring.



Terrestrial plants take up huge amount water daily but most of it is lost to the air through evaporation from the leaves, i.e., transpiration.



A mature corn plant absorbs three liters of water in a day while mustard plant absorbs water equal to it weight in 5 hours for growth & productivity.



Water plays an important role in many useful reactions within the cells.



Water is useful for maintaining the turgidity of cells which is essential for cell enlargement, growth & development.



Water is used to regulate the heat in plants through transpiration, guttation, evaporation.

Water Potential 

The term water potential was proposed by Slatyer & Taylor.



The term water potential is used in the place of DPD (diffusion pressure deficit) & SP (suction pressure). The difference between free energy of water in a system & free energy of pure water at atmospheric pressure is also called water potential. Water potential is defined as the chemical potential of water divided by the partial molal water (i.e. the volume of 1 mol of water). It is a measure of the free energy associated with water per unit volume (Jm–3)



TRANSPORT IN PLANTS 

453

Water potential (Ψw) is a concept fundamental to understanding water movement. Solute potential (Ψs) and pressure potential (Ψp) are the two main components that determine water potential.



Water molecules possess kinetic energy. In liquid and gaseous form they are in random motion that is both rapid and constant.



The greater the concentration of water in a system, the greater is its kinetic energy or ‘water potential’. Hence, it is obvious that pure water will have the greatest water potential.



If two systems containing water are in contact, random movement of water molecules will result in net movement of water molecules from the system with higher energy to the one with lower energy. Thus, water will move from the system containing water at higher water potential to the one having low water potential.



This process of movement of substances down a gradient of free energy is called diffusion.



Water potential is denoted by the Greek symbol Psi or Ψ and is expressed in pressure units such as bars or pascals (Pa). (1 MPa = 10 bars)



By convention, the water potential of pure water at standard temperatures, which is not under any pressure, is taken to be zero. If some solute is dissolved in pure water, the solution has fewer free water and the concentration of water decreases, reducing its water potential. Hence, all solutions have a lower water potential than pure water, the magnitude of this lowering due to dissolution of a solute is called solute potential or osmotic potential or Ψs.



Ψs is always negative. The more the solute molecules, the lower (more negative) is the Ψs. For a solution at atmospheric pressure, the water potential Ψw = (solute potential) Ψs.



If a pressure greater than atmospheric pressure is applied to pure water or a solution, its water potential increases. It is equivalent to pumping water from one place to another.



Pressure can build up in a plant system when water enters a plant cell due to diffusion causing a pressure built up against the cell wall, it makes the cell turgid; this increases the pressure potential.



Pressure potential is usually positive (and operates in plant cells as wall pressure and turgor pressure) though in plants negative potential or tension in the water column in the xylem plays a major role in water transport up a stem. Pressure potential is denoted as ψ w. = ψ s + ψ p Water potential of a cell is affected by both solute and pressure potential. The relationship between them is as follows : ψ w = ψs + ψp



Problem – Movement of water between two adjacent cells : Suppose A and B are two adjacent plant cells where osmotic movement of water can occur. Cell A has osmotic potential (Ψs) of –16 bars and pressure potential of 8 bars. The cell B has osmotic potential of –12 bars and pressure potential of 2 bars. Using the relationship between water potential, pressure potential & osmosis /suction potention, Identify the direction of the movement of water.

Cell A Ψs = –16 Ψp = 8

Ψ = Ψs +Ψp = 2 – 16 + 8 = – 8

Cell B Ψs = –12 Ψp = 2

Ψ = Ψs + Ψp = – 12 + 2 = –10

Since water moves from higher water potential to lower potential, the flow of water will be from cell A to B (i.e. – 8 bar to – 10 bars).

Check Point Fill in the blanks. (i) The water potential of pure water is __________. (ii) When plant absorbs water from the soil, the water potential of the root cell is_________than the soil. (iii) Water potential is the sum of two opposing forces in plant cell ______ & _______. (iv) A water melon has over _____% of water. (v) Water potential is denoted by _______ symbol____or____ . (vi) Ψ is always________. (vii) Water potential (Ψp) can be calculated by ______+_______. (viii) Solute potential is also called ______ potential. (ix) The amount by which the water potential is reduced as a result of the presence of solute is called________ . (x) If a pressure greater than atmospheric pressure is applied to pure water or a solution, its water potential________.

Connecting Concepts  The lower the water potential in a plant cell or tissue, the greater is its ability to absorb water. Conversely, the higher the water potential, the greater is the ability of the tissue to supply water to other more desiccated cells & tissues. Thus, the water potential is used to measure water deficit & water stress in the plant cells & tissues.  Trambe (1867) use copper ferrocyanide and developed semipermeable membrane to show its utility in the osmosis of plant physiology. First time Pfeffer in (1887) developed osmoscope by using semipermeable membrane.

454

BIOLOGY

Osmosis 

The term osmosis was coined by Abby Nollet (1978).



Osmosis is a kind of diffusion that plays a role in the movement of water into & within plants. In plants, it is the diffusion of water from higher concentration to lower concentration across a semi–permeable or differentially–permeable membrane.



Diffusion continues across the membrane until an equilibrium is obtained.



The net direction and rate of osmosis depends on pressure and concentration gradient.



Osmosis can also be defined as “the diffusion of water from its pure state into the solution when the two are separated by semipermeable membrane or it is the diffusion of water or solvent from a dilute solution to a concentrated solution through a semipermeable membrane”.



A solution which can cause the osmotic entry of water into it is said to be osmotically active solution.



Common experiment for demonstrating osmosis is thistle funnel experiment and potato osmoscope. (i) Thistle funnel experiment - In the experiment sucrose solution is taken in funnel which is separated from water through semi-permeable membrane. Water will move into funnel till the equilibrium is reached. Pressure

Thistle funnel

h Sucrose solution

Beaker

• •• • • Water (a) Water will diffuse across the membrane

Membrane

• • •• •

(b) Pressure can be applied to stop the water movement into the funnel

Fig. 11.3 A demonstration of osmosis theory ‘Thistle funnel experiment’.

Connecting Concepts  Saline plants have higher osmotic pressure : Species indigenous to saline soil usually have relatively high osmotic pressure. Such soils are rich in soluble salts & the high osmotic pressure found in species native to such soil result from the absorption of relatively large quantities of mineral salt. In fact, the highest recorded osmotic pressure for any species of plant (202.5 atm) was found in the saltbush Atriplex confertifolia a saline soil species.

 





The experiment proves that the sugar solution is an osmotically active solution & can absorb water when it is separated from the water by a semipermeable membrane. (ii) Potato osmoscope - Experiment useful for demonstrating osmosis by using living tissue is potato osmoscope. When the tuber is placed in water, the cavity in the potato tuber containing a concentrated sugar, solution collects water due to osmosis.The entry of water into the sugar solution proves that sugar solution is osmotically active. The cytoplasm of the cells of the tuber that lie between the sugar solution & the water acts as a single semipermeable membrane. Types of osmosis - Depending upon the movement of water into or outside of the cell. Osmosis is of two types-endosmosis & exosmosis. The osmotic flow of water into a cell, when it is placed in a solution, whose solute concentration is less than that of the cell sap, is called endosmosis. Eg. swelling of raisins when they are placed in water. The osmotic outflow of water from a cell, when it is placed in a solution, whose solute concentration is more than that of the cell sap is called exosmosis. Eg. shrinkage of grapes when they are placed in concentrated sugar solution. Reverse osmosis is the expulsion of pure water from a solution through a semipermeable membrane under the influence of external pressure higher than the OP (osmotic potential) of solution. Reverse osmosis is used in removing salts from saline water as well as extra purification of water.

TRANSPORT IN PLANTS 

Osmotic pressure (term proposed by Pfeffer) is the pressure required to prevent the entry of water into a solution. Osmotic pressure is a positive value. Pure solvent has no osmotic pressure.



When solute is added to pure solvent it develops osmotic pressure.



Osmotic pressure and osmotic potential are numerically equal, but osmotic potential has a negative sign.

455

Ψs = – π [when Ψs = Osmotic potential of solution; π = osmotic pressure].



Osmotic pressure can be calculated by OP – CRT, where, C is molar concentration of solution, R is gas constant & T is absolute temperature.



The value of osmotic pressure is related to number of particles & not molecules.



Osmosis depends on two factors (i)

Concentration of dissolved solutes in a solution.

(ii) Pressure difference. Significance of osmosis •

Responsible for absorption of water by roots.

•

Responsible for cell to cell movement of water throughout the plant.

•

Responsible for turgidity of plant organs.

•

Responsible for opening & closing of stomata.

•

Responsible for resistance of plant to drought, frost, etc.

Problem : Refer the given figure in which two chambers P & Q containing solutions having different concentrations are separated by a semi-permeable membrane. And answer the following questions.

(i)

Which chamber has a lower water potential?

(ii)

In which direction will osmosis occur ?

(iii)

Which solution has a higher solute potential ?

(iv)

At equilibrium which chamber will have lower water potential.

(v)

If one chamber has a Ψ of –2000 kPa & other –1000 kPa, then which is the chamber that has the higher Ψ and what is it ?

Solutions : (i)

Chamber Q has lower concentration of water hence possesses lower water potential.

(ii)

Osmosis will occur from higher Ψ to lower Ψ so it will occur from chamber P to chamber Q.

(iii)

The solution in chamber Q has higher solute concentration, hence possesses higher solute potential (Ψs).

(iv)

At equilibrium water potential in both the chambers (i.e. on both side of the semipermeable membrane) will be equal.

(v)

Chamber P has higher water potential (Ψ) which is – 1000 kpa

Check Point State True or False. (i) Osmosis involves the selectively permeable membrane. (ii) Osmosis can operate in any medium. (iii) An animal cell placed in pure water will swell up & burst. (iv) Swelling of wooden door during rainy season is due to endosmosis. (v) Bacteria cannot survive in highly salted pickles because they become plasmolysed & death occurs. (vi) To demonstrate the phenomenon of osmosis one may used boiled & peeled potato. (vii) Term plasmolysis was coined by Nollet (1978). (viii) Osmotic pressure & osmotic potential are numerically equal, but osmotic potential has a negative sign. (ix) When the protoplast just begin to contract away from the cell wall, it is called evident plasmolysis. (x) The value of TP becomes zero during incipient & evident plasmolysis.

Connecting Concepts  Leaf of Tradescantia is used for demonstration of plasmolysis in laboratory because their cells contain anthocyanin pigments.

456

BIOLOGY

Plasmolysis 

The shrinkage of the protoplast of a living cell from its cell wall due to exosmosis under the influence of a hypertonic solution is called plasmolysis. Water moves out; it is first lost from the cytoplasm and then from the vacuole. The water when drawn out of the cell through diffusion into the extracellular (outside cell) fluid causes the protoplast to shrink away from the walls. The cell is said to be plasmolysed. The movement of water occurred across the membrane moving from an area of high water potential (i.e., the cell) to an area of lower water potential outside the cell.



The stage of plasmolysis, when the protoplast just begins to contract away from the cell wall is called incipient plasmolysis.



The stage when the cell wall has reached its limit of contraction and the protoplast has detached from cell wall attaining spherical shape is called evident plasmolysis. If a cell with incipient plasmolysis is placed in a hypertonic solution it will show more plasmolysis.



When the cells are placed in a hypotonic solution (higher water potential or dilute solution as compared to the cytoplasm), water diffuses into the cell causing the cytoplasm to build up a pressure against the wall, that is called turgor pressure (TP) . The pressure exerted by the protoplasts due to entry of water against the rigid walls is called pressure potential Ψp. Because of the rigidity of the cell wall, the cell does not rupture. This turgor pressure is ultimately responsible for enlargement and growth of cells.



When the cell (or tissue) is placed in an isotonic solution, there is no net flow of water towards inside or outside. If the external solution balances the osmotic pressure of the cytoplasm it is said to be isotonic. When water flows into the cell and out of the cell and are in equilibrium, the cells are said to be flaccid.



The swelling up of a plasmolysed protoplast due to endosmosis under the influence of a hypotonic solution or water is called deplasmolysis. Deplasmolysis is possible only immediately after plasmolysis otherwise the cell protoplast becomes permanently damaged. The value of TP (turgor pressure) becomes zero at the time of limiting plasmolysis and below zero during incipient and evident plasmolysis.

Fig. 11. 4 Plasmolysis and deplasmolysis (a) Normal cell (b) Plasmolysed cell (c) Deplasmolysed cell and increased turgor pressure

Connecting Concepts

Significane of plasmolysis

 Isotonic solution : When concentration  of outer solution (in which cell in placed) is equal to concentration of cell sap, called as isotonic solution and there is no flow of  water.  Hypotonic solution : When concentration of outer solution is lower  than concentration of cell sap, called as hypotonic solution and the water diffuses into cell to make it turgid.



The OP of a cell can be measured by plasmolysis. The OP of a cell is roughly equal to the OP of a solution that causes incipient plasmolysis in the cell. Salting of pickles, meat, fishes etc and addition of sugar to jams, jellies, cut fruits etc., prevent their decay by microbes as the latter get killed due to plasmolysis or due to high concentration of salt or sugar. By salting, the weeds can be killed from tennis courts and the growth of plants can be prevented in the cracks of walls. Plasmolysis is helpful in determining whether a particular cell is living or dead as

 Hypertonic solution : When plasmolysis does not occur in a dead or non living cell. concentration of outer solution is higher than concentration of cell sap, Imbibition called as hypertonic solution and the  The process of absorption of water by hydrophilic surfaces of a substance without forming water diffuses from the cell.

a solution is called imbibition. It is a type of diffusion by which movement of water takes place along a diffusion gradient. The solid particles which adsorb water or any other liquid are called imbibants. The liquid which is imbibed is known as imbibate.



Examples of imbibition are adsorption of water by seeds, dry wood, starch cellulose, agar, gelatin, gum etc.

TRANSPORT IN PLANTS Characteristics of imbibition

457 Check Point



Significance of turgidity in plants The phenomenon of imbibition has three important characteristics – volume change, (1) It provides stability to a cell. production of heat & development of imbibitional pressure.



Volume change : During the process of imbibition, imbibants increase in volume. It has organelles (mitochondria plastids been observed that there is an actual compression of water. This is due to arrangement of and microbodies) fully distended. water molecules on surface of imbibant and occupy less volume than the same molecules This is essential for plants to live and do when are in free state in the normal liquid, e.g, if a dry piece of wood is placed in water, grow normally. they swell and increases in its volume. (3) Turgor pressure helps in cell enlargement, consequently in Production of heat : As the water molecules are adsorbed on the surface of the imbibant, stretching of the stems and in their kinetic energy is released in the form of heat which increases the temperature of the keeping leaves erect and fully medium. It is called heat of wetting (or heat of hydration), e.g., during kneading, the flour of expanded. wheat gives a warm feeling due to imbibition of water and consequent release of heat.





(2) Turgidity keeps the cell and their

(4) The turgid cells provide mechanical

Development of imbibitional pressure : Imbibition pressure can be defined as the support necessary for the non maximum pressure that an imbibant will develop when it is completely soaked in pure woody tissues (maize, sugarcane, water. Imbibition pressure is also called as the matric potential (Ψm) because it exists banana etc.) due to the presence of hydrophilic substance in the cell which include organic colloids (5) Loss of turgidity leads to wilting of and cell wall. leaves and drooping of shoots. (6) The opening and closing of stomata are regulated by the turgidity of the Nature of imbibant : Proteins are the strongest imbibants of water, starch less strong, guard cells. cellulose being the weakest. (7) Leaf movements (seismonastic movement) of many plants (such Surface area of imbibant : If more surface area of the imbibant is exposed and is in as bean, sensitive plant Mimosa contact with liquid, the imbibition will be more. pudica) are controlled by loss and Temperature : Increase in temperature causes an increase in the rate of imbibition. gain of cell turgor. (8) Due to turgor pressure plumule and Degree of dryness of imbibant : If the imbibant is dry it will imbibe more water than a radicles force out from seeds at the relatively wet imbibant. time of seed germination.

Factors influencing the rate of imbibition      

Concentration of solutes : Increase in the concentration of solutes in the medium decreases imbibition.

pH of imbibant : Proteins, being amphoteric in nature, imbibe least in neutral medium. Towards highly acidic or highly alkaline pH, the imbibition increases till a maximum is reached, there after it starts slowing down.

Significance of imbibition 

The water is first imbibed by walls of root hairs and then absorbed.



Water is absorbed by germinating seeds through the process of imbibition and helps in rupturing of seeds coat (made up of cellulose).



The water moves into ovules which are ripening into seeds by the process of imbibition.

LONG DISTANCE TRANSPORT OF WATER 

Transport of substances over longer distances through the vascular tissue, i.e., xylem and phloem, is called translocation. It occurs through mass flow.



Mass flow is the movement of substances in bulk or en masse from one point to another as a result of pressure differences between the two points. It is a characteristic of mass flow that substances, whether in solution or in suspension, are swept along at the same pace. This is unlike diffusion where different substances move independently depending on their concentration gradients.



Bulk flow can be achieved either through a positive hydrostatic pressure gradient (e.g., a garden hose) or a negative hydrostatic pressure gradient (e.g., suction through a straw). The direction of translocation is essentially unidirectional in case of water (from root to stem, leaves, flowers and fruits) and multidirectional in case of minerals and organic solutes. Organic compounds are synthesized in leaves.

458

BIOLOGY

How do plant absorbs water 

 

Connecting Concepts



 Casparian strips is a band of radial  cell walls in the endodermis that is impregnated with the wax like,  hydrophobic substance called suberin. Suberin acts as a barrier to water and  solute movement.  Cytoplasmic streaming : Also called cyclons is an autonomous vital movement that occurs continuously in the cytoplasm of eukaryotic cells  around the central vacuole. It can be  observed in the cells of Hydrilla (an aquatic plant) leaf.  The movement of chloroplast due  to cytoplasmic streaming can be seen  under the microscope. 

 Check Point 1. 2. 3. 4. 5.

6. 7. 8.

Tissues associated with translocation are_______. Organic compounds are synthesized in ________. ________ coined the term apoplast & symplast. Symplastic movement occurs from cell to cell through ________. ________ breaks the continuity of the apoplast pathway & forces the water & solutes to cross the endodermis by passing through ________. The hyphae have large surface area for ________. From soil, root hairs absorbs water by ________. The direction of translocation is ________in case of water & ________ in case of mineral & organic solutes.





Water may be absorbed through almost any surface of a plant but most of the absorption of water & mineral salts occur in terminal portion of roots. Because of excessive branching of roots there are numerous root tips that helps in obtaining water & minerals from the soil. In higher plants, water is absorbed through root hairs. From soil, root hairs absorbs water by diffusion. The water moves through root cortex and to xylem elements. Roots hairs are thin-walled and they increases absorption area. Water is absorbed along with mineral solutes, by the root hairs, purely by diffusion. Once water is absorbed by the root hairs, it can move deeper into root layers by two distinct pathways: (a) apoplast pathway (b) symplast pathway Munch coined the term apoplast & symplast. Apoplastic movement of water occurs exclusively through cell wall and intercellular spaces; without crossing any membrane. It is continuous throughout the plant, except at the casparian strips of the endodermis in the roots. This movement is dependent on the gradient. The apoplast does not provide any barrier to water movement and water movement is through mass flow. As water evaporates into the intercellular spaces or the atmosphere, tension develop in the continuous stream of water in the apoplast, hence mass flow of water occurs due to the adhesive and cohesive properties of water. Symplastic movement occurs from cell to cell through plasmodesmata. During symplastic movement, the water travels through the cells – their cytoplasm; intercellular movement is through the plasmodesmata. Movement is relatively slower and aided by cytoplasmic streaming. Major proportion of water flow in the root cortex occurs via the apoplast. Beyond cortex the apoplastic water movement is blocked by casparian strip. Beyond endodermis, water is forced to move through the cell membrane – or the symplast. Once the water reaches root xylem, transpiration drives water to move to the leaves through the stem. Mycorrhizal water absorption : Some plant have additional structures associated with them that help in water & minerals absorption. In mycorrhiza a large number of fungal hyphae are associated with young root and also extend into soil. The hyphae have large surface area for absorption. The hyphae absorbs water and minerals and handed over them to root. Root provides the fungus with sugar and nitrogenous compound. Some plants have an obligate association with the mycorrhizae. For example, Pinus seeds cannot germinate and establish without the presence of mycorrhizae. Plasmodesmata

Epidermis

Plasma membrane

Cortex

Endodermis

Pericycle

Xylem = apoplast Cell Wall = symplast

Casparian strip

Fig. 11.5 Absorption of water (pathway of water movement in root)

TRANSPORT IN PLANTS

Fig. 11.6 Symplastic & apoplastic pathways of water & ion absorption & movement in roots.

Mechanism of water absorption 

Two distinct mechanism which are independently operated in the absorption of water in plants are active absorption and passive absorption.



Renner (1912,1915) coined the term active and passive water absorption.



Active absorption : Active absorption takes place by the activity of root itself, particularly root hairs. The factor responsible for water absorption is present within the roots. It utilizes metabolic energy. •

There are two theories of active absorption- osmotic & non osmotic theory.

•

Osmotic theory was proposed by Atkins (1916) and Priestley (1922). It is purely a physical process, which does not directly require expenditure of energy.

•

In this type of absorption, the OP of cell sap of root hair is higher than that of OP of soil water. DPD & suction pressure in root hair becomes higher than soil water. Therefore water enters though the plasma membrane by osmotic diffusion. As a result, the OP, suction pressure & DPD of root hair now becomes lower, while TP is increased. Non-osmotic theory was proposed by Thimann (1951) and Kramer (1959). It has been observed that absorption of water still occurs, if the concentration of cell sap in the root hair is lower than that of the soil water, or water is absorbed against concentration gradient (i.e., from higher DPD to lower DPD). Such type of water absorption occurs on the expense of energy obtained from respiration.

•

Fig. 11.7 Passive absorption of water through root hair



Passive absorption : It was the most common and rapid method of water absorption. The factor responsible for water absorption is present somewhere else than roots. It accounts for about 98% of the total water uptake by plant. •

According to this theory, the forces responsible for absorption of water originate not in the cells of roots but in the cells of transpiring shoots. The root cells remain passive.

459

460

BIOLOGY Connecting Concepts

Water movement up a plant (Ascent of sap)

 Ringing experiments were proposed  by Malpighi & Stephen Hales to demonstrate the ascent of sap takes place through xylem vessels.  Root pressure theory is not acceptable because root pressure is  absent in gymnosperms & actively  transpiring plants, though ascent of sap occurs in them.



The water absorbed by plants is also called sap because it is actually a dilute solution of minerals. Ascent of sap or translocation of water is usually upward movement of water or sap from root towards the top of the plant. It occurs through tracheary elements of xylem. The rate of ascent of sap is 10–75 cm/min. Path of ascent of sap : It is now well established that the ascent of sap takes place through xylem. In herbaceous plants almost all the tracheary elements participate in the process, but in large woody trees the tracheary elements of only sap wood are functional. Further, it has been proved experimentally that sap moves up the stem through the lumen of xylem vessels and tracheids and not through their walls. Several theories have been put forward to explain the mechanisms of ascent of sap. Two main theories are - root pressure theory and cohesion tension - transpiration pull model. Root pressure theory

Check Point Fill in the blanks. (i) The upward transport of water along with dissolved minerals from roots to the aerial parts of the plant is called __________. (ii) Root hair absorbs water from soil through_____. (iii) Most accepted theory of ascent of sap is_______. (iv) Root pressure is maximum when transpiration is_____________ and absorption is _________.



When ion from the soil actively transported into vascular tissue of root, water follows (its potential gradient) and pressure increases inside the xylem. This positive pressure is called as root pressure and can be responsible for pushing up water to small heights in the stem.



The term root pressure was coined by Stephen Hales. Root pressure can be measured by manometer.



Root pressure theory was proposed by Priestley (1916). This theory explains mechanism of ascent of sap in herbs.



According to this theory the water which is absorbed by the root-hairs from the soil collects in the cells of the cortex. The cortical cells become fully turgid. In such circumstances the elastic walls of the cortical cells, exert pressure on their fluid-contents and force them towards the xylem vessels. Due to this loss of water, these cortical cells become flaccid, again absorb water, become turgid and thus again force out their fluid contents. Thus, the cortical cells of the root carry on intermittent pumping action, as a result of which considerable pressure is set up in the root. This pressure forces water up the xylem vessels.



Effects of root pressure is also observable at night and early morning when evaporation is low, and excess water collects in the form of droplets around special openings of veins near the tip of grass blades, and leaves of many herbaceous parts. Such water loss in its liquid phase is known as guttation (term coined by Bergerstein).



Guttation takes place through hydathodes (are stomata like pores generally present at the top margin of the leaves of those plants that grows in moist shady place).



Root pressure, only provide a modest push in the overall process of water transport. They obviously do not play a major role in water movement in tall trees. The greatest contribution of root pressure may be to re-establish the continuous chains of water molecules in the xylem which often break under the enormous tensions created by transpiration. Root pressure does not account for the majority of water transport; most plants meet their need by transpiratory pull. Cohesion - Tension Transpiration Pull model



This is the most widely accepted theory put forward by Dixon and Jolly in 1894, and further supported by Renner (1911,1915), Curtis and Clark (1951), Bonner and Golston (1952), Kramer and Kozlowski (1960).

TRANSPORT IN PLANTS

461



It is also known as Dixon’s cohesion theory, or cohesion tension theory.



This theory relies upon the following factors (i)

formation of continuous water column (in xylem vessel).

(ii)

cohesive force between the water molecules.

(iii) transpiration pull brings about the ascent of sap. Evaporation of water from the leaf to atmosphere decreases the water potential of the epidermal cells.



Water moves from adjacent cells along water potential gradient.



Water lost from the leaf cells is, in turn replaced by water moving from the xylem elements in leaf veins. Thus, it forms a continuous water column from root to leaves due to cohesive and adhesive properties of water molecules.



Uptake of water in this way is also referred to an transpirational pull. Transpiration pull is a force developed in mesophyll cells due to transpiration. This tension or pull results in upward movement of water.



In this way the water rises due to the transpiration pull and the cohesive power of water molecules from the lowest parts of the roots to the highest peaks of the trees. The osmotic pressure in the transpiring leaf cells often reaches to 30 atmospheres whereas only 20 atmospheres are needed to raise the water to the tops of highest known trees.

Give a scientific term (i) The osmotic pressure of cell sap of root hair is higher than that of DP of soil water. (ii) The most common and rapid method of water absorption. (iii) Tissue concerned with ascent of sap in plants. State true or false. (i) Ascent of sap will be maximum during night. (ii) Root pressure is sufficient for the transport of water in slowly transpiring herbaceous plants. (iii) Ascent of sap was demonstrated by girdling experiment in plant. (iv) Transpiration pull is a force developed in spongy cells due to transpiration.

Vessels and tracheids



Check Point

Fig. 11.8 Path of ascent of sap showing transpiration pull

Connecting Concepts

 Potomoter - An instrument for measuring the rate of transpiration by Loss of water in the form of water vapour from plant through the small pores (stomata) shoots by measuring the rate of their water absorption. present on leaves is called transpiration.

TRANSPIRATION  

Maximum transpiration occurs in mesophytic plants. About 98% of water absorbed by  Porometer - An instrument for measuring the degree of stomatal land plants evaporates from the aerial parts & diffuse into the atmosphere. opening.

462

BIOLOGY Table 11.2 : Differences between transpiration and evaporation Transpiration

Evaporation

(1)

It is a physiological process and occurs in plants.

It is physical process and occurs on any free surface.

(2)

The water moves through the epidermis Any liquid can evaporate. The living with its cuticle or through the stomata. epidermis and stomata are not involved.

(3)

Living cells are involved.

(4)

Various forces (such as vapour pressure, Not much forces are involved. diffusion pressure, osmotic pressure, etc.) are involved.

(5)

It keeps the surface of leaf and young stem wet and protects from sun burning.

It can occur from both living and nonliving surfaces.

It causes dryness of the free surface.

Flow Chart 11.2 Types of transpiration Connecting Concepts

Structure of Stomata 

Types of stomata (i) Barley or cereal type (dumbbell shaped, e.g. maize, wheat). Open for a few hours during the day. (ii) Alfalfa or leucerne type (e.g.  pea, bean, grape) : Remain open throughout the day, close at night. (iii) Potato type (e.g. potato, cucurbita,  banana) : Open throughout day & night but close for a few hours in case of water deficiency. (iv) Equisetum type (e.g. emergent hydrophytes) : Remain open & seldom close.

Stomata are minute pores present on leaf epidermis. Besides the loss of water vapour in transpiration, exchange of oxygen and carbon dioxide in the leaf also occurs through pores called stomata (sing. : stoma). Normally stomata are open in the day time and close during the night. Stoma (stomatal pore) is bordered by kidney shaped guard cells. Guard cells are surrounded by epidermal cells called subsidiary cells. The inner wall of each guard cell, towards the pore or stomatal aperture, is thick and elastic. When turgidity increases within the two guard cells flanking each stomatal aperture or pore, the thin outer walls bulge out and force the inner walls into a crescent shape. The opening of the stoma is also aided due to the orientation of the microfibrils in the cell walls of the guard cells. Cellulose microfibrils are oriented radially rather than longitudinally making it easier for the stoma to open. When the guard cells lose turgor, due to water loss (or water stress) the elastic inner walls regain their original shape, the guard cells become flaccid and the stoma closes.

TRANSPORT IN PLANTS 

463

Dorsiventral leaf (dicot) have more stomata on lower surface while isobilateral or (monocot) have equal number of stomata on both the surface.

Fig. 11.9 A stomal aperture with guard cells



Scotoactive stomata opens in dark & close during day time. These occur in succulents. Table 11.3 Difference between activities during opening & closing of stomata. Stomata open

Stomata close

1. Stomata opens in day time (light).

Stomata close in night time (darkness).

2. Photosynthesis occurs.

No photosynthesis occurs

3. Osmosis of water into the guard cell.

Osmosis of water out of the cell.

4. Guard cells become turgid.

Guard cells become flaccid.

5. Glucose collects in the guard cells causing Glucose concentration drops. an increase in concentration of the cell sap.

6. Guard cells start to swell.

Guard cells start to shrink.

7. The outer wall stretches more than thick

Reverse changes occur.

inner wall due to turgor.

8. Pore forms between the guard cells stoma. Closes pore between the cells. 9. Effect – Increases rate of gaseous exchange & transpiration.

Effect – No gaseous exchange or transpiration.

Fig. 11.10 Stomatal apparatus

464

BIOLOGY

MAIN THEORIES ABOUT THE MECHANISM OF STOMATAL MOVEMENT (i) Guard cell photosynthesis theory : Given by Schwendenes (1881) and also accepted by Von Mohl (1856).

Chloroplast in guard cell (Photosynthesis in day time) Formation of sugar in guard cell

Osmotic concentration in guard cell increases

Induces water absorption from adjacent cells

Guard cells turgids

Stomata open (ii)

Starch hydrolysis theory : First given by Llyod. Formulated by J.D. Sayre (1923) & Modified by Steward (1964).

In Day time

In Night time (dark)

TRANSPORT IN PLANTS (iii)

465

Malate or K+ ion pump theory : Proposed by Levitt (1974) & elaborated by Raschke

(1975) & Bowling (1976).

During Day time





During Night time

The transpiration driven ascent of xylem sap depends on the following physical properties of water. •

Cohesion – mutual attraction between water molecules.

•

Adhesion – attraction of water molecules to polar surfaces (such as the surface tracheary elements).

Check Point

1. of (i)

State True & False. In darkness, high pH & high CO2 concentration govern the closing of stomata. • Surface tension – water molecules are attracted to each other in the liquid phase more (ii) Stomata function as a turgor operthan to water in the gas phase. ated valves. (iii) The walls of kidney shaped guard • They give water high tensile strength, i.e., an ability to resist a pulling force, and cells are thickened on the outer capillarity, i.e., the ability to rise in thin tubes. side. The process of photosynthesis requires water. The system of xylem vessels from the root to (iv) In barley or other cereals, guard the leaf vein can supply the needed water. As water evaporates through the stomata, since cells of stomata are kidney shaped.

the thin film of water over the cells is continuous, it results in pulling of water, molecule (v) by molecule, into the leaf from the xylem. Also, because of lower concentration of water vapour in the atmosphere as compared to the substomatal cavity and intercellular spaces, water diffuses into the surrounding air. This creates a ‘pull’. (vi)

Measurements reveal that the forces generated by transpiration can create pressures sufficient to lift a xylem sized column of water over 130 metres high.

2.

Stomatal opening depend upon the availability of + ions from the adjacent epidermal cells. Excessive rate of transpiration lead to faster growth of plants. Name two plants in which dumb bell shaped guard cells are found.

466

BIOLOGY

Fig. 11.11 : Water movement in the leaf. Evaporation from the leaf sets up a pressure gradient between the outside air and the air spaces of the leaf. The gradient is transmitted into the photosynthetic cells and on the water-filled xylem in teh leaf vein.

Connecting Concepts

Factors Affecting transpiration

 Anti-transpirants : The chemical substances which reduce transpiration External factor (by increasing leaf resistance to Humidity – When humidity is high, the rate of transpiration is low. water vapour diffusion) without  affecting gaseous exchange, are called  Temperature – Rate of evaporation doubles with rise in temperature by 10°C. But high anti-transpirants’. Anti-transpirants temperature reduces transpiration. are of two types - metabolic inhibitors and film forming  Wind speed – High wind speed increases transpiration. anti-transpirants.



 Metabolic inhibitors : Reduce transpiration by causing partial closure of stomata without influencing other metabolite processes, the most important of these inhibitors are phenyl  mercuric acetate (PMA), and abscissic acid (ABA).

Light : Light affects the rate of transpiration due to its effect on temperature and photosynthesis. During daytime stomata open wide but during night they close. Thus increased temperature and presence of wide open stomata increase the rate of transpiration. Light is the most important factor in the regulation of transpiration. Maximum opening of stomata occurs in red light (660 nm), followed by blue light (445 nm) and no opening occurs in green light, UV light and far red light.

 Film forming anti-transpirants : Internal factors Check transpiration by forming a thin  Leaf area : If leaf area is more, transpiration is faster. However, the rate of transpiration transparent film on the transpiring per unit area is more in smaller leaves than in larger leaves due to high number of stomata surface. They are sufficiently permeable in a small leaf. Number of stomata per unit area of leaf is called stomatal frequency. to carbon dioxide and oxygen to allow photosynthesis and respiration, but S = I × 100 here, I = Stomatal index. prevent movement of water vapour E+S through them. The important chemicals S = No. of stomata per unit area. of this group are silicon emulsion, E = No. of epidermal cells in unit area. colourless plastic resins and low viscosity waxes.



Leaf structure : The anatomical features of leaves like sunken or vestigial stomata: presence of hair, cuticle or waxy layer on the epidermis,: presence of hydrophilic substances such as gums, mucilage etc. in the cells; compactly arranged mesophyll cells etc. help in reducing the rate of transpiration.



Root-shoot ratio : According to Parker (1949), the rate of transpiration is directly proportional to the root-shoot ratio.



Age of plants : Germinating seeds show a slow rate of transpiration. It becomes maximum at maturity. However, it decreases at senescence stage.



Orientation of leaves : If the leaves are arranged transversely on the shoot they lose more water because they are exposed to direct sunlight. If placed perpendicularly they transpire at slower rate.

TRANSPORT IN PLANTS

Significance of transpiration The advantages and disadvantages of transpiration are discussed below: Advantages •

Transpiration is important for plants because it directly influences the absorption of water from the soil.

•

Transpiration exerts a tension or pull on water column in xylem which is responsible for the ascent of sap.

•

Transpiration helps in the movement of water and minerals absorbed by the roots to the other parts of the plant.

•

The evaporation of water during transpiration contributes the cooling of leaves (and also the surrounding air) and protects leaves from heat injury particularly under conditions of high temperature and intense sunlight.

Disadvantages •

Transpiration often results in water deficit which causes injury to the plants by desiccation.

•

Rapid transpiration causes mid-day leaf water deficit (temporary wilting). If such condition continues for some time, permanent water deficit (permanent wilting) may develop, which causes injury to plants.

•

Many xerophytes have to develop structural modifications to reduce transpiration. These modifications are extra burden on plants.

•

Excessive rate of transpiration leads to stunted growth of plants.

•

Since approximately 90 percent of absorbed water is lost through transpiration, the energy used in absorption and conduction of water goes waste.

•

Inspite of various disadvantages the plant cannot avoid transpiration due to their peculier structure of leaves which is basically meant for gaseous exchange during respiration & photosynthesis. Therefore, transpiration is also regarded as ‘necessary evil’ by Curtis (1926) or unavoidable evil by Steward (1959).

Transpiration and Photosynthesis 

Transpiration has more than one purpose; it •

creates transpiration pull for absorption and transport of plants.

•

supplies water for photosynthesis.

•

transports minerals from the soil to all parts of the plant.

•

cools leaf surfaces, sometimes 10 to 15 degrees, by evaporative cooling.

•

maintains the shape and structure of the plants by keeping cells turgid.



An actively photosynthesizing plant has need for water. Photosynthesis is limited by available water which can be swiftly depleted by transpiration. The humidity of rainforests is largely due to this vast cycling of water from root to leaf to atmosphere and back to the soil.



The evolution of the C4 photosynthetic system is probably one of the strategies for maximising the availability of CO2 while minimising water loss.

UPTAKE & TRANSPORT OF MINERAL NUTRIENTS 

Plants obtain their supply of carbon and most of their oxygen from CO2 of atmosphere, hydrogen from water. Minerals are picked up individually from the soil.

467

468

BIOLOGY

Uptake of Mineral ions       

  

Minerals exist in the soil as ions which cannot directly cross the cell membranes. The concentration of ions is some 100 times more in root interior than in the soil. Ions are absorbed from the soil by both passive and active transport. The movement of ions from soil to interior of root is against concentration gradient and requires an active transport. Specific ion pumps occur in the membrane of root hairs, which pumps mineral ions from soil to cytoplasm of epidermal cells of root hairs. Energy is provided by ATP, respiratory inhibitors like cyanide which inhibit ATP synthesis, generally reduce the ion uptake. The ions are again checked and transported inwardly by transport proteins present over the endodermal cells. Endodermis allows the passage of ions inwardly but not outwardly. It also controls the quantity and type of ions to be passed into xylem. Inward flow of ions from epiblema to xylem is along the concentration gradient. The collection of ions in the xylem is responsible for water potential gradient in the root that helps in osmotic entry of water as well as its passage to xylem. In the xylem, minerals are carried up alongwith the flow of xylem solution through transpirational stream. In leaves, the cells absorb the minerals selectively through membrane pumps.

Translocation of Mineral ions  

    

Generally xylem transports inorganic nutrients while phloem transports organic nutrients. But in xylem sap, nitrogen travels as inorganic ions, as well as organic form (amino acids) and related compounds. Small amounts of P and S are passed in xylem as organic compounds. There is also exchange of materials between xylem and phloem. They reach the area of their sink (utilization), namely young leaves, developing flowers, fruits and seeds, apical and lateral meristems and individual cells for storage. Minerals are unloaded at fine vein endings through diffusion, picked up by cells through active uptake. There is remobilization of minerals like nitrogen, sulphur, phosphorous and potassium from older senescing parts. Elements incorporated in structural components are, however, not remobilised, e.g., calcium. The remobilised minerals become available to young growing leaves and other sinks. Nickel has prominent role in remobilization.

TRANSPORT IN PHLOEM    



It is the long distance movement of organic substances from the source or supply end (region of manufacture or storage) to the region of utilization or sink. But the source and sink may be reversed depending on the season or need of the plants. Sugar stored in roots may be mobilised to become a source of food in the early spring when the buds of trees act as sink and require energy for their growth and development. Since, the source-sink relationship is variable, the direction of movement of organic solutes in phloem can be upwards or downwards i.e., bidirectional. bidirectional

This contrasts with that of the xylem where the movement is always unidirectional, i.e., upwards. Hence, unlike one-way flow of water in transpiration, food in phloem sap can be transported in any required direction so long as there is a source of sugar and a sink able to use, store or remove the sugar.

TRANSPORT IN PLANTS 

Phloem sap is mainly water and sucrose, but other sugars, hormones and amino acids are also transported or translocated through phloem.

The pressure flow or mass flow hypothesis  













The accepted mechanism for the translocation of sugars from source to sink is called the pressure flow hypothesis. It was put forward by Munch (1930). According to this hypothesis, organic substances move from the region of high osmotic pressure to the region of low osmotic pressure in a mass flow due to the development of a gradient of turgor pressure. As glucose is prepared at the source (by photosynthesis), it is converted to sucrose (a disaccharide). The sugar is then moved in the form of sucrose into the companion cells and then into the living phloem sieve tube cells by active transport. This process of loading at the source produces a hypertonic condition in the phloem. Water in the adjacent xylem moves into the phloem by osmosis. As osmotic pressure builds up the phloem sap will move to areas of lower pressure. At the sink, osmotic pressure must be reduced. Again active transport is necessary to move the sucrose out of the phloem sap and into the cells which will use the sugar - converting it into energy, starch, or cellulose. As sugars are removed, the osmotic pressure decreases and water moves out of the phloem. To summarise, the movement of sugars in the phloem begins at the source, where sugars are loaded (actively transported) into a sieve tube. Loading of the phloem sets up a water potential gradient that facilitates the mass movement in the phloem. Phloem tissue is composed of sieve tube cells, which form long columns with holes in their end walls called sieve plates. Cytoplasmic strands pass through the holes in the sieve plates, so forming continuous filaments. As hydrostatic pressure in the phloem sieve tube increases, pressure flow begins, and the sap moves through the phloem. Meanwhile, at the sink, incoming sugars are actively transported out of the phloem and removed as complex carbohydrates. The loss of solute produces a high water potential in the phloem, and water passes out, returning eventually to xylem. A simple experiment, called girdling, was used to identify the tissues through which food is transported. On the trunk of a tree a ring of bark up to a depth of the phloem layer, can be carefully removed. In the absence of downward movement of food the portion of the bark above the ring on the stem becomes swollen after a few weeks. This simple experiment shows that phloem is the tissue responsible for translocation of food; and that transport takes place in one direction i.e., towards the roots.

Fig. 11.12 Pathway and mechanism of phloem translocation

469 Check Point 1. Element which has prominent role in remobilization is _________. 2. Minerals exists in the soil in _________ form. 3. Inward flow of ions from epiblema to xylem is_________ the concentration gradient. 4. The direction of phloem transport is___________ . 5. Tissue responsible for translocation of food is _________. 6. The hypothesis accepted for the translocation of sugar from source to sink is _________.

470

BIOLOGY

EXERCISE - 1 | NCERT BASED QUESTIONS 1.

Active and passive transports across cell membrane differ in

(1) (2) (3) (4)

(1) passive transport is non-selective. (2) passive transport is along the concentration gradient while active transport is due to metabolic energy. (3) active transport is more rapid. (4) passive transport is confined to anions while active transport in confined to cations. 2.

1.

2. 3. 4.

4.

Needs carrier protein Uphill transport Transport saturates Needs ATP energy

Yes

Yes

No

Yes

Yes

No

No

No

No

No

Yes

A boy is studying transport of a certain type of molecules into cell. He finds that transport slows down when the cells are poisoned with a chemical that inhibits energy production. Under normal circumstances the molecules studied by the boy is probably transported by (1) simple diffusion (2) osmosis (3) active transport (4) facilitated diffusion The figure shows facilitated diffusion. Identify the process occuring at I, II and III.

III

Co-port Antiport Symport Uniport

Symport Uniport Co-port Antiport

Antiport Symport Antiport Symport

If a plant cell is immersed in water, the water continues to enter the cell until the (2) concentration of the salts is the same inside the cell as outside.

Simple Facilitated Active Diffusion Diffusion Transport Yes

II

(1) cell bursts.

The table below shows the comparison of different transport process. Identify the correct comparison. Property

3.

5.

I

(3) concentration of water is the same inside the cell as outside. (4) diffusion pressure deficit is the same inside the cell as outside. 6.

“Osmosis is the diffusion of a solution of a weaker concentration when both are separated by semipermeable membrane above”. What is the error in the statement ? (1) The movement of solvent molecule is not specified. (2) There is no mention of DPD. (3) Behaviour of semipermeable membrane is not specified. (4) The exact concentration of solutions are not indicated.

7.

Osmosis means movement of (1) solute from low concentration to higher. (2) solute from higher concentration to low. (3) solvent from low concentration of solution to higher concentration of solution. (4) solvent from higher concentration of solution to low concentration of solution.

8.

9.

A plant cell placed in pure water will (1) expand until the osmotic potential or solute potential reaches that of water. (2) becomes more turgid until the pressure potential of cell reaches its osmotic potential. (3) become more turgid until the osmotic potential reaches that of pure water. (4) becomes less turgid until the osmotic potential reaches that of pure water. Imbibition causes (1) increase in the volume of imbibant but no pressure development. (2) decrease in the volume of imbibant and pressure develops.

TRANSPORT IN PLANTS

10.

11.

12.

(3) no change in volume of imbibant but pressure develops. (4) volume of imbibant increases and pressure develops. During osmosis, water moves through a membrane From To (1) Low water potential High water potential (2) High solute Low solute concentration concentration (3) High osmotic Low osmotic potential potential (4) A hypotonic solution A hypertonic solution (less solute) (more solute) Osmosis cannot be demostrated by a potato osmoscope using a solution of NaCl instead of sugar, because the potato tissue is (1) permeable to sodium ion (2) permeable to chloride ion (3) permeable to salt solution (4) impermeable to salt solution Study the experiment shown below.

471

16.

17.

18.

19.

13.

14. 15.

After a few days, which of the following will have occurred? (1) A rise in level X and Y. (2) A drop in level X and level Y. (3) A rise in level X and a drop in level Y. (4) A drop in level X and a rise in level Y. How water potential Ψ is affected by the presence of solutes and insoluble colloids? (1) Ψ is increased. (2) Ψ is decreased. (3) Remains unchanged. (4) Increased for solutes and decreased for colloids. Water potential is equal to (1) Ψs + O.P. (2) Ψs = T.P. (3) Ψp + Ψw (4) Ψs + Ψp Study the figure and choose the correct statement regarding this.

20.

21.

(1) Kinetic energy (K.E.) of H2O in A solution > K.E. of water in B solution. (2) K.E. of water in B solution > K.E. of water in A solution. (3) K.E. of water in A solution = K.E. of H2O in B solution. (4) Water potential has nothing to do with K.E. of water in a solution. Seeds when soaked in water, they imbibe because of (1) OP inside the seed is low. (2) OP of water is high. (3) DPD of seed is very much low. (4) Water potential gradient between the seed coat and water. Which of the following statement is not correct? (1) Plants absorb excess quantity of water. (2) Plants take small quantity of mineral salts through soil water. (3) Plant absorb only one thing at a time-water or inorganic salts (4) None of the above Plants die from prolonged water-logging because (1) soil nutrients become very dilute. (2) root respiration stops. (3) cell sap in the plants becomes too dilute. (4) nutrients leach down due to excess water. The pathway of water from soil upto the secondary xylem is (1) Soil → root hair → cortex → endodermis → pericycle → protoxylem → metaxylem. (2) Metaxylem → protoxylem → pericycle → cortex → endodermis → soil → root hair. (3) Cortex → root hair → endodermis → pericycle → protoxylem → metaxylem. (4) P e r i c y c l e → s o i l → r o o t h a i r → c o r t e x → endodermis → protoxylem → metaxylem Water moving through the apoplast from the soil to stele cells must crosses a plasma membrane in the cells of (1) root hairs (2) cortex (3) endodermis (4) vessel The primary difference between the apoplast and the symplast is that the (1) apoplast is non-living spaces in cell walls. (2) apoplast relies on active transport. (3) symplast is nonliving spaces in cell wall. (4) apoplast prevents passive diffusion.

22.

23.

The casparian strip prevents water and minerals from entering the stele through the (1) plasmodesmata (2) apoplast (3) symplast (4) xylem vessel Root pressure is maximum, when (1) transpiration is low and absorption is high.

472

24.

BIOLOGY (2) transpiration is high and absorption is low. (3) both transpiration & absorption are high. (4) both transpiration & absorption are low. When a plasmolysed cell is placed in water or hypotonic solution, what happens? (1) TP of cell decreases.

(2) OP & TP increases (3) OP decreases, TP increases 32.

(4) OP & TP decreases Given below is the diagram of stomatal apparatus. In which of the following all of the three parts labelled as A, B and C are correctly identified?

(2) TP of cell becomes zero. (3) TP increases. 25.

(4) Water potential of cell decreases.

A B

The speed of water absorption will be greater if

C

Subsidiary cell

(1) the difference between osmotic pressure of soil water and that of xylem vessels is always less. (2) the difference between osmotic pressure of soil water and that of xylem vessels is always more.

(1) A - Microfibril, B - Stomatal aperture, C - Guard cell

(3) the osmotic pressure of soil water is always more than that of xylem vessels.

(3) A - Stomatal aperture, B - Guard cell, C - Microfibril

(2) A - Microfibril, B - Guard cell, C - Stomatal aperture (4) A - Guard cell, B - Stomatal aperture, C - Microfibril

(4) the osmotic pressure of soil water is always less than that of xylem vessels. 26.

Stomata open and close due to (1) circadian rhythm (2) genetic clock (3) pressure of gases inside the leaves (4) turgor pressure of guard cells

27.

33.

An adaptation for better gaseous exchange in plant leaves is presence of (1) hair on lower surface (2) multiple epidermis

34.

(3) waxy cuticle (4) stomata on lower surface away from direct sun rays 28.

Transpiration from plants would be most rapid when (1) there is lot of humidity in atmosphere. (2) the air is more humid. (3) there is excess rain fall. (4) environmental conditions are dry.

29.

Increase in CO2 concentration around leaf results in (1) rapid opening of stomata. (2) partial closure of stomata.

35.

(Q. 33 and 34) Direction : In the following questions more than one of the answer given may be correct. Select the correct answer and mark it according to the code. Code : (1) a, b & c are correct. (2) a, b are correct. (3) b, d are correct. (4) a, c are correct. Which of the following is true regarding guttation? (a) Occurs through stomata (b) Occurs through hydathodes (c) Loss of pure water (d) Occurs mostly during night and early morning Which of the following statement is correct? (a) A mature corn plant absorbs about 3 litres of water in a day. (b) Water is often limiting for plant growth & productivity in both agricultural & natural environment. (c) In 5 hours, a mustard plant absorbs water equal to its own weight. (d) A dry alive & respiring seeds has no water at all. Match the name of the activities listed under column I with the description of activity given under column II. Column I A. Transpiration B. Guttation C. Exudation

(3) complete closure of stomata. (4) no effect on stomatal opening. 30.

31.

D. Fermentation

Which of the following wall of guard cells is thick? (1) Outer

(2) Inner

(3) Sidewall

(4) All the three

In case of open stomata, identify the changes takes place in the guard cell. (1) OP increase, TP decreases

(1) (2) (3) (4)

Column II Anaerobic respiration in yeast II. Active absorption of water III. Loss of water vapour from plant parts IV. Loss of liquid water from leaves. V. Loss of water from injured plant parts. I.

A-I; B-II; C-III; D-V A-II; B-I; C-IV; D-III A-III; B-IV; C-V; D-I A-IV; B-V; C-II; D-III

TRANSPORT IN PLANTS 36.

37. 38.

39.

According to transpiration-cohesion theory water is pulled upward through the xylem. The cause of the pull is (1) guttation (2) root pressure (3) transpiration (4) condensation Bidirectional translocation of minerals takes place in (1) xylem (2) phloem (3) parenchyma (4) cambium Multidirectional flow of a variety of organic and inorganic solutes occurs through (1) xylem (2) vascular tissue (3) phloem (4) root A botanist discovered a mutant plant that was unable to produce materials that form casparian strip. This plant would (1) unable to transport water or solutes to the leaves. (2) unable to use its sugar as a sugar sink. (3) able to exert greater root pressure than the normal plant.

473

40.

(4) unable to control amounts of water and solutes it absorbs. Which of the following statements are correct? I. No energy is expanded directly by the plant to translocate water. II. The mechanisms of water transport from the soil through the plant body to the atmosphere include diffusion, bulk flow and osmosis. III. Water moves in the root via the apoplast, transmembrane, and symplast pathway. IV. The cohesion tension theory explains water transport in phloem. (1) I, II, III, IV (2) I, II and III (3) III & IV (4) Only IV

474

BIOLOGY

EXERCISE - 2 | Window to Competitive Exams 1.

2.

3.

4.

5.

6.

7.

8.

9.

10.

The movement of mineral ions into plant root cells as a result of diffusion is called [CBSE’96] (1) osmosis (2) active absorption (3) passive absorption (4) endocytosis Water potential in the leaf tissue is positive (+) during [CBSE’97] (1) excessive transpiration (2) low transpiration (3) excessive absorption (4) guttation With increase in the turgidity of a cell surrounded by water the wall pressure will [CBSE’97] (1) increase (2) decrease (3) fluctuate (4) remain unchanged Seed increase in its volume by the adsorption of water through [BHU'97] (1) osmosis (2) diffusion (3) imbibition (4) plasmolysis If a cell A with D.P.D. 4 bars is connected to cell B, C, D whose O.P. and T.P. are respectively 4 and 4, 10 and 5 and 7 and 3 bars, the flow of water will be [CBSE’98] (1) A and D to B and C (2) A to B,C and D (3) B to A, C and D (4) C to A, B and D Turgor pressure become equal to the wall pressure when [BHU'98] (1) water leaves the cell. (2) water enter the cell. (3) no exchange of water takes place. (4) solute goes from cell into water. Water potential of actively absorbing cells is [CBSE'99] (1) always +ve (2) always –ve (3) always 0 (4) always >1 In soil, the water available for root absorption is [Manipur PMT'06, Orissa'06, CBSE'91, 99] (1) gravitational water (2) capillary water (3) hygroscopic water (4) combined water Process by which water enters in the roots due to diffusion, is termed as [AMU'99] (1) osmosis (2) endocytosis (3) active absorption (4) passive absorption What will be the direction of movement of water, when a solution A having water potential of –9 bars and another solution B –4 bars is separated by a semipermeable membrane? [AMU'2000] (1) B to A (2) A to B (3) Both directions (4) None of these

11.

12.

13.

14.

15.

16.

17.

18.

19.

20.

Which of the following is not performed by root hairs ? [AMU'2000] (1) Water uptake (2) Oxygen uptake (3) Mineral uptake (4) CO2 uptake When water moves through a semi-permeable membrane then which of the following pressure develops? [CBSE’01] (1) O. P. (2) S. P. (3) T. P. (4) W. P. A fibrous root system is best adapted to perform which one of the following functions? [AMU'01] (1) Storage of food. (2) Anchorage of the plant into the soil. (3) Absorption of water and minerals from the soil. (4) Transport of water and organic food. The plants may face wilting due to use of excess fertilizers because of [AMU'02] (1) endosmosis (2) exosmosis (3) imbibition (4) transpiration The rate of transpiration in plants is dependent upon [AMU'97, 02] (1) temperature and soil (2) light and temperature (3) wind, temperature and light (4) light, temperature, atmospheric humidity and wind When a cell is fully turgid, which of the following will be zero ? [AMU'02] (1) Wall pressure (2) Osmotic pressure (3) Turgor pressure (4) Water potential Exchange of substances between individual cells and their environments taken place by [BHU'02] (1) osmosis (2) active transport (3) diffusion (4) All of these Stomata of a plant open due to [CBSE’03] (1) influx of calcium ions (2) influx of potassium ions (3) efflux of potassium ions (4) influx of hydrogen ions Water stomata are found in [AMU'03] (1) plants lacking normal stomata. (2) plants inhabiting dry regions. (3) plants inhabiting humid region. (4) all plants. Which part of root absorbs both water and minerals? (1) Zone of cell differentiation [AMU'03] (2) Zone of cell formation (3) Zone of cell elongation (4) Terminal portion of root

TRANSPORT IN PLANTS 21.

22.

23.

24.

25.

26.

27.

28.

29.

30.

31.

The osmotic parameter determining the flow of water from one cell to another is [AMU'03] (1) O.P. (2) D.P.D. (3) T.P. (4) hydrostatic pressure Solution outside a cell has higher concentration than cytoplasm. Then the solution is [AMU'03] (1) isotonic (2) acidic (3) hypotonic (4) hypertonic Which one of the following doesn’t help in molecule transport? [BHU'03] (1) Diffusion (2) Osmosis (3) Surface tension (4) Active transport Movement of ions or molecules in a direction opposite to that of prevailing electrochemical gradient is known as [CBSE'2000, BIHAR CECE'04] (1) diffusion (2) active transport (3) pinocytosis (4) brownian movement Guttation is the result of [Orissa'09, CBSE'11M, AMU'04] (1) diffusion (2) transpiration (3) osmosis (4) root pressure The membrane which allows passage of certain substances more readily than others is termed as [AMU'4] (1) permeable (2) selectively permeable (3) semipermeable (4) impermeable Who proposed the “Cohesion Theory” of ascent of sap? [AMU'04] (1) Strasburger (2) Godlewski (3) Western (4) Dixon and Jolly If water enters in a cell, the pressure exerted by its swollen protoplast is [AMU'04] (1) turgor pressure (2) D.P.D. (3) osmotic pressure (4) imbibition Starch is insoluble in water, yet it is accumulated in large quantities in potato tuber because [UP CPMT'04] (1) it is useful for storage. (2) starch is synthesised in tubers. (3) tubers respire slowly. (4) translocated sucrose is polymerised here. Which of the following theories of ascent of sap was proposed by an eminent Indian scientist J.C. Bose? [Kerala CET'04] (1) Pulsation theory (2) Relay pump theory (3) Transpiration pull theory (4) Root pressure theory Guard cells control [Bihar CECE'04] (1) closing and opening of stomata (2) photosynthesis (3) intensity of light entering leaves (4) change in green colour

475 32.

33.

34.

35.

Which one of the following statements is correct? [J & K PMT'04] (1) DPD = OP – WP (2) DPD = OP + WP (3) DPD = WP – OP (4) DPD = WP + OPD Which one of the following are responsible for opening and closing of stomata ? [J & K PMT'04] (1) Rise in pH of guard cells causes hydrolysis of starch. (2) Cytokinins and cyclic AMP are required. (3) Abscisic acid promotes closure. (4) All of the above. Passive absorption of mineral salts is not dependent upon [J & K PMT'04] (1) diffusion (2) osmosis (3) donnan equilibrium (4) ionic exchange. Match the theories given in column I with the name of scientists listed in column II. Choose the answer which gives the correct combination of the alphabet. [Karnataka CET'04] Column I (a) Relay Pump Theory (b) Transpiration Cohesion Theory (c) Mass Flow Theory (d) Pulsation Theory

Column II (I) (II)

Stocking Sir J. C. Bose

(III) (IV) (V)

Godlewski Dixon and Jolly Ernest Munch

(1) a–III,b–II,c–V,d–I (2) a–II,b–I,c–V,d–III (3) a–III,b–IV,c–V,d–II (4) a–IV,b–III,c–I,d–II 36.

37. 38. 39.

40.

Potometer works on the principle of [CBSE’05] (1) osmotic pressure (2) amount of water absorbed equals the amount transpired (3) root pressure (4) potential difference between the tip of the tube and that of the plant When stomata open, the pH of guard cells [AMU'05] (1) increases (2) decreases (3) remains same (4) Both (1) and (2) Water lost in guttation is [AMU'05] (1) pure water (2) impure water (3) in vapour form (4) Either (1) or (2) Wilting occurs when [AMU'04,05] (1) rate of transpiration is higher than absorption. (2) rate of absorption is higher than transpiration. (3) there is excess root pressure. (4) there is high relative humidity in air. A cell when dipped in 0.5 M sucrose solution has no effect but when the same cell will be dipped in 0.5 M NaCl solution, the cell will [AMU'05] (1) increase in size (2) decrease in size (3) will be turgid (4) will get plasmolysed

476 41.

42.

43.

BIOLOGY Wilting in plant occurs due to [AMU'01, 05] (1) blockage of xylem (2) blockage of phloem (3) Both (1) and (2) (4) increased transpiration Casparian strip is made up of [HPPMT'05,Kerala'05] (1) lignin (2) pectin (3) suberin (4) cellulose Match the following [Kerala'05] Column I

44.

Column II

(a) Hypotonic (I) Water (b) Hypertonic (II) Sucrose (c) Solute (III) Lower tonicity (d) Solvent (IV) Higher tonicity (1) a–I,b–II,c–III,d–IV (2) a–III,b–II,c–I,d–IV (3) a–III,b–IV,c–II,d–I (4) a–III,b–II,c–IV,d–I The following figure shows the stomatal apparatus. Identify the parts labelled as a, b, c, dd. Choose the correct answer from the following. [Karnataka CET'05]

a

b c

d

45.

46.

47.

(1) a–subsidiary a cell, b–chloroplasts, c–stoma, d–guard d cells (2) a–guard cell, b–stoma, c–chloroplast, d–subsidiary d cells (3) a–guard cell, b–chloroplast, c–stoma, d–subsidiary d cells (4) a–subsidiary cell, b–stoma, c–chloroplast, d–guard d cell. In which of the following plants, there will be no transpiration ? [Karnataka CET'05] (1) Aquatic submerged plants (2) Plants living in deserts (3) Aquatic plants with floating leaves (4) Plants growing in hilly regions. Identify the correct statements from the following. [A.P.M.E.E.'05] (A) Accumulation of K+ ions in the guard cells does not require energy. (B) A high pH favours stomatal opening. (C) Movement of chloride ion into guard cells as in response to the electric differential created by K+ ions. (D) With entry of several K+ ions and chloride ions, water potential of guard cells increases. The correct combination is (1) (A) and (C) (2) (A) and (B) (3) (B) and (C) (4) (C) and (D) The value of osmotic potential (π) and pressure potential ( ) of cells a, b, c, d are given below (p [A.P.M.E.E.'05] Cells

48.

49. 50. 51. 52.

53.

54.

55. 56. 57.

58.

59.

Cells π P – 1.0 0.5 a b – 0.6 0.3 c – 1.2 0.6 d – 0.8 0.4 Identify the correct sequence that shows the path of movement of water from the following (A) d c a b (B) b d a c (C) b c d a b a d (D) c Force developed in cortex of root which pushes water into xylem of root soil is [Orissa'05] (1) diffusion (2) osmotic pressure (3) turgor pressure (4) root pressure. Guttation occurs through [Orissa'05] (1) lenticels (2) hydathodes (3) periderm (4) stomata Sunken stomata are found in leaves of [Orissa'05] (1) Trifolium (2) Lemna (3) Nerium (4) Lilium Transpiration is mainly a process of [Orissa'05] (1) osmotic pressure (2) imbibition (3) diffusion (4) respiration. Stomata open in the day time due to [Wardha'05] (1) increase in water potential (2) decrease in water potential (3) decrease in pH (4) light If two solutions have the same osmolarity. They are said to be [J.K.C.M.E.E.'05] (1) hypotonic (2) hypertonic (3) isotonic (4) none of these The potential energy of water is referred as [J.K.C.M.E.E.'05] (1) water potential (2) osmotic potential (3) gravity potenital (4) pressure potential. In tall trees, water is absorbed due to [Manipal'05] (1) root pressure (2) capillary action (3) transpiration pull (4) photosynthesis Wilting in plants occurs due to [Manipal'05] (1) endosmosis (2) exosmosis (3) difusion (4) imbibition The term ‘water potential’ was given by [AMU'01, BV'06] (1) Dixon and Jolly (2) Prof. R.C. Sirohi (3) J.C. Bose (4) Slatyer and Tayler The translocation of organic solutes in sieve tube members is supported by [CBSE’06] (1) P-proteins. (2) mass flow involving a carrier and ATP. (3) cytoplasmic streaming. (4) root pressure and transpiration pull. Conversion of starch to organic acids is required for [CBSE'92, MP PMT'10, RP PMT'06] (1) stomatal opening (2) stomatal closing (3) stomatal formation (4) stomatal activity

TRANSPORT IN PLANTS 60.

61.

62.

63.

64.

65.

66.

67.

68.

69.

Who proposed a theory about ascent of sap ? [C.E.T. Chd.'06] (1) Mc Clung (2) J. C. Bose (3) A. leming (4) J. Lederberg Which is incorrect ? [C.E.T. Chd.'06] (1) Diffusion is movement of particles from low electrochemical potential to high electrochemical potential. (2) Rate of diffusion is directly proportional to concentration. (3) Rate of diffusion is inversely proportional to distance (4) Example of diffusion is opening of a bottle of scent in one corner. In a turgid cell which will be zero? [C.E.T. Chd.'06] (1) Turgor pressure (2) Wall pressure (3) Suction pressure (4) Osmotic pressure Action spectrum of transpiration consists of [C.E.T. Chd.'06] (1) Green and ultraviolet (2) Orange and red (3) Blue and far-red (4) Blue and red Influx of K+ ions of subsidiary cells into guard cells and efflux of H+ ions from guard cells lead to [C.O.M.E.D -K’s'06] (1) closing of stomata (2) opening of stomata (3) exosmosis (4) plasmolysis Upward movement of water through xylem is best explained by [C.O.M.E.D -K’s'06] (1) cohesion (2) pulsation (3) capillary (4) root pressure Translocation of carbohydrates in phloem occurs in the form of [C.O.M.E.D -K’s'06] (1) starch (2) fructose (3) maltose (4) surcose Which of the following is used as antitranspirant? [K.C.E.T.'06] (1) Calcium carbonate (2) Phenyl mercuric acetate (3) Cobalt chloride (4) Naphthol acetic acid. Water is lost in liquid state in some plants through hydathodes. These hydathodes [K.C.E.T.'06] (1) remain always open (2) do not show any specificity in opening and closing (3) remain closed at night (4) remain closed during day The rate of transpiration will be very less in a situation where [K.C.E.T.'06] (1) environment is very hot and dry (2) relative humidity is very high (3) ground water is sufficiently available (4) wind is blowing with a very high velocity.

477 70.

71.

72. 73.

74.

Identify the correct relationship with reference to water potential of a plant cell? [K.C.E.T.'06] (1) ψw = ψm – (ψs + ψp) (2) ψw = ψm – ψs – ψp (3) ψw = ψm + ψs + ψp (4) ψw = ψm + (ψs – ψp) Passive absorption of water by root system is the result of [K.C.E.T.'06] (1) tension on the sap due to transpiration. (2) osmotic force in the shoot system. (3) force created in the cells of the root. (4) increased respiratory activity in root cells. Upward movement of water in plants is called (1) sucking (2) ascent of sap [Orissa'06] (3) translocation (4) none of these Oozing out of water drops from injured edges or tips is called [Orissa'06] (1) oozation (2) bleeding (3) guttation (4) transpiration Match List – I with List – II and find out the correct answer from the code given below. [P.M.T. Manipur'06] List – I List – II

(a) Diffusion (b) Osmosis

(i) (ii)

hydrophoilic substances

(c) Imbibition

(iii) semipermeable membrane

shrinkage of protoplasm

(d) Plasmolysis (iv) free movement of ions and gases

75.

76.

77. 78.

79.

(1) a – (ii), b – (i), c –(iv), d – (iii) (2) a – (iv), b – (iii). c – (i), d – (ii) (3) a – (iii), b – (i), c – (iv), d – (ii) (4) a – (ii), b – (iii), c – (iv), d – (i) Lenticels and hydathodes are small pores with one of the following common attribute [A.M.U. P.M.D.C'06] (1) They allow exchange of gases. (2) Their opening and closing is not regulated. (3) They always remain closed. (4) They are found on the same organ of plants. Osmotic pressure of a solution is [BHU'07] (1) greater than pure solvent. (2) less than pure solvent. (3) equal to pure solvent. (4) less than or greater than pure solvent. Root hair absorbs water from soil through [BHU'07] (1) turgor pressure (2) ion exchange (3) osmosis (4) DPD Osmosis involves [BHU'04, BHU Screening07] (1) flow of water without a membrane. (2) flow of solute from a semipermeable membrane. (3) flow of solvent (H2O) through a semi-permeable membrane. (4) None of the above. Cause of guttation is [Karnataka CET 07] (1) atmospheric pressure (2) DPD (3) root pressure (4) vapour pressure

478 80.

81.

82.

83.

84.

85.

86.

87.

88.

89.

BIOLOGY Which of the following experiment is called physiologica demonstration of osmosis ? [Karnataka C.E.T'07] (1) Potometer (2) Bell jar experiment (3) Thistle funnel whose mouth is tied with egg membrane. (4) Thistle funnel whose mouth is tied with parchment paper. When the concentration of the soil solutes is low, the absorption of water is [Karnataka C.E.T'07] (1) increased (2) decreased (3) remain normal (4) stopped Munch hypothesis is based on [Karnataka C.E.T'07] (1) translocation of food due to turgor pressure (TP) gradient. (2) translocation of food due to imbibition force. (3) translocation of food due to TP gradient and imbibition force. (4) None of these The metal ions involved in opening and closing of stomata is [Karnataka C.O.M.E.D. -K’s'07] (1) Fe+++ (2) Cu++ + (3) K (4) Mg++ What will be the effect of accumulation of K+ ions in guard cells ? [Gujarat C.E.T'07] (1) Loss of turgidity (2) Exosmosis (3) Water potential increases (4) Water potential decreases The rate of transpiration of a plant would gradually increase if [H.P.P.M.T'07] (1) the relative humidity increases. (2) the relative humidity decreases. (3) the relative humidity remains unchanged. (4) the water potential gradient remains unchanged. Absorption of diffusible ions by cells against concentration gradient is called [H.P.P.M.T'07] (1) passive absorption (2) active absorption (3) osmosis (4) donnan equilibrium A cell swells up when kept in [U.P. - C.P.M.T'07] (1) hypotonic solution (2) hypertonic solution (3) isotonic solution (4) any of the three If flowers are cut and dipped in dilute NaCl solution then (1) endo-osomosis occurs [U.P. - C.P.M.T'07] (2) transpiration is low (3) no bacterial growth takes place (4) absorption of solute inside flower cell takes place. Phenomenon of plasmolysis occurs when [Orissa J.E.E'07] (1) cells are kept in hypertonic solution (2) cells are kept in hypotonic solution (3) cells are kept in hypotonic solution (4) none of the above

90.

91.

92.

93.

94.

95. 96.

97.

98.

Osmotic pressure of a solution is usually measured in [Manipur'007] (1) Kelvin (2) Joule (3) Pascal (4) Newton Dry wooden stakes, if driven into a small crack in a rock and then soaked, can develop enough pressure to split the rock. Such a pressure is built up through the phenomenon of [Punjab P.M.T'07] (1) imbibition (2) prop roots (3) turgor pressure (4) buttress roots Two cells A and B are contiguous. Cell A has osmotic pressure 10 atm, turgor pressure 7 atm and diffusion pressure deficit 3 atm. Cell B has osmotic pressure 8 atm, turgor pressure 3 atm and diffusion pressure deficit 5 atm. The result will [CBSE'07] (1) no movement of water. (2) equilibrium between the two. (3) movement of water from cell A to B. (4) movement of water from cell B to A. Carbohydrates are commonly found as starch in plant storage organs. Which of the following five properties of starch (A-E) make it useful as a storage material? [CBSE’08] (A) Easily translocated (B) Chemically non-reactive (C) Easily digested by animals (D) Osmotically inactive (E) Synthesized during photosynthesis The useful properties are (1) (B) and (C) (2) (B) and (D) (3) (A), (C) and (E) (4) (A) and (E) The rupture and fractionation do not usually occur in the water column in vessel/tracheids during the ascent of sap because of [CBSE’08] (1) lignified thick walls (2) cohesion and adhesion (3) weak gravitational pull (4) transpiration pull The lowest water potential is found in [AMU'08] (1) leaves (2) xylem (3) root hair (4) phloem Opening of stomata is not affected by [D.P.M.T'08] + (1) N2 (2) K ions (3) starch (4) None of these A leaf peeling of Tradescantia is kept in a medium having 10% NaCl. After a few minutes if we observe the peel under the microscope, we are likely to see [K.C.E.T'08] (1) the cells bursting out (2) entry of water into the cell (3) exit of water from the cell (4) diffusion of NaCl into the cell. The energy source responsible for upward flow of water lies in ............... [C.O. M.E.D. - K’s'08] (1) A T P (2) solar heat (3) sucrose (4) light

TRANSPORT IN PLANTS 99.

100.

101.

102.

103.

104.

105.

106.

107.

108.

479

A plant cell elongates due to ............... [C.O. M.E.D. - K’s'08] (1) production of more cytoplasm (2) increased nucleoplasm content (3) taking up of water (4) secondary growth In a fully turgid cell .......... [C.O. M.E.D. - K’s'08] (1) ψs will be negative and ψp will be positive. (2) ψp will be negative and ψs will be positive. (3) Both ψp and ψs will be positive. (4) Both ψs and ψp are negative. Which of the following is provided to plant by fungi present in mycorrhiza? [Gujarat C.E.T'08] (1) Carbonate (2) Phosphate (3) Chloride (4) Nitrate. Primary and secondary active transport both [W.B.'08] (1) generate ATP. (2) use ATP directly. (3) can move solutes against their concentration gradient. (4) include the passive movement of glucose molecule. In which method of transport in plasma membrane does not require carrer molecule ? [W.B.'08] (1) Active transport (2) Simple diffusion (3) Facilitated diffusion (4) Na+ – K+ pump. Root pressure is higher when [Orissa'08] (1) Transpiration is very low and absorption is high (2) Transpiration is very high and absorption is high (3) Transpiration is low and absorption is low (4) Transpiration is high and absorption is low. When stomata close which of the following events does not occur? [Orissa'08] (1) Guard cells become flaccid. (2) Sugar is converted to starch. (3) O.P. of the guard cells decreases. (4) Accumulation of O2 takes place. The phenomenon of plasmolysis is evident when cells are kept in [Orissa'08] (1) hypotonic solution (2) hypertonic solution (3) isotonic solution (4) none of the above Osmosis is diffusion of [Orissa'08] (1) solute (2) free energy (3) water (4) solute and solvent Study the following table showing the components of water potential in closely arranged mesophyll cells namely p, q, r. [E.A.M.C.E.T'08] Cell p q r

Osmotic potential (MPa) – 0.21 – 0.22 – 0.23

Pressure potential (MPa) 0.05 0.02 0.05

109.

110.

111.

112.

113.

114.

115.

Identify two of the following which show correct direction of water movement between two cells. (a) p q (b) q r (c) r p (d) r q The correct pair is (1) a, b (2) b, c (3) a, d (4) b, d In photoactive plants, during daytime the following ionic flux of guard cell directly involves the expenditure of energy [E.A.M.C.E.T'08] (1) outward movement of malate. (2) outward movement of protons. (3) inward movement of potassium ions. (4) inward movement of chloride. Which of the following statements is/are not true? [Kerala P.M.T'08] (a) In CAM plants stomata open during dark and remain closed during the day. (b) Role of Na+ in stomatal opening is now universally accepted. (c) The water potential of root cells is higher than the water potential of soil. (d) Capilliarity theory is the most accepted theory of water movement through plants. (e) The walls of xylem vessels made up of lignocellulose have strong affinity for water molecules. (1) b, c and e only (2) b, c and d only (3) a, b and c only (4) b and c only Most accepted theory for ascent of sap is [CPMT'08] (1) pulsation theory (2) transpiration pull theory (3) capillary theory (4) root pressure theory Which of the following theory gives the latest explanation for the closure of stomata ? [CPMT'08] (1) Munch theory (2) ABA theory (3) Starch glucose theory (4) Active K+ transport theory Guard cells help in [Orissa '09, CBSE'09] (1) transpiration (2) guttation (3) fighting against infection (4) protection against grazing A cell, when kept in sugar solution, gets dehydrated. Then solution is [AMU'09] (1) hypotonic (2) hypertonic (3) isotonic (4) none of these Which of the following cells are not related to the structure of stomata? [Gujarat C.E.T'09] (1) Epidermal cells (2) Guard cells (3) Sclerenchymatous cells (4) Accessory cells.

480 116. What happens when concentration of solutes decreases in guard cells ? [Gujarat C.E.T'09] (1) Water potential decreases (2) Water potential increases (3) Osmotic pressure increases (4) None of these 117. Which of the following is appropriate for mass-flow hypothesis ? [Gujarat C.E.T'09] (1) Large amount of ions are also absorbed along with the absorption of water. (2) As suction pressure increases, absorption of water increases and alongwith water, absorption of ion also increases. (3) Transpiration pull is responsible for absorption of ions. (4) All the given options. 118. The translocation sugars in angiosperms occurs in the form of [C.E.T. Chd.'09] (1) glucose (2) sucrose (3) fructose (4) lactose 119. Which one of the pathways of water movement involves cell wall and intercellular spaces ? [C.O.M.E.D - K’s'09] (1) Vacuolar pathway (2) Protoplast pathway (3) Symplast pathway (4) Apoplast pathway. 120. The efflux of K+ and Cl– will cause [C.O.M.E.D - K’s'09] (1) closure of stomata (2) opening of stomata (3) increased turgidity (4) imbibition 121. Vein loading of sucrose into companion cell is due to [C.O.M.E.D - K’s'09] (1) active transport (2) passive transport (3) turgor pressure (4) diffusion 122. Stoma opens when [K.C.E.T.'09] (1) guard cells swell due to a decrease in their water potential. (2) guard cells swell up due to an increase in their water potential. (3) guard cells swell by endosmosis due to efflux of potassium ions. (4) guard cells swell by endosmosis due to influx of hydrogen ions (protons). 123. Transpiration facilitates [K.C.E.T.'09] (1) electrolyte balance (2) absorption of water by roots (3) opening of stomata (4) excretion of minerals. 124. Which of the following would be in insignificant amount in xylem sap ? [K.C.E.T.'09] (1) Sugar (2) Phosphate (3) Water (4) Nitrates

BIOLOGY 125. Water potential of pure water and its solution are [Manipur'09] (1) 0 and 1 (2) 0 and 0 (3) 0 and more than one (4) 0 and less than 1. 126. Bacteria cannot survive in a highly salted pickle because [Manipur'09] (1) salt inhibits reproduction of bacteria. (2) they become plasmolysed and death occurs. (3) nutrients in pickle cannot support life. (4) enough light is not available for photosynthesis. 127. The force of cohesion develops due to [M.H.T.C.E.T'09] (1) attraction between similar molecules (2) attraction between different molecules (3) surface tension at the interface (4) All the above. 128. Major loss of water in transpiration occurs through [M.H.T.C.E.T'09] (1) cuticle (2) bark (3) hydathodes (4) stomata 129. Guard cells help in: [CBSE PMT 2009] (a) transpiration (b) guttation (c) fighting against infection (d) protection against grazing 130. Cohesion theory of water movement in plants was put forth by [Kerala PMT 2009] (a) Melvin Calvin (b) F. F. Blackman (c) T. W. Englemann (d) Henry Dixon (e) Hans A. Krebs 131. Select the correct events leading to the opening of the stomata [Kerala PMT 2009] (A) decline in guard cell solutes (B) lowering of osmotic potential of guard cells (C) rise in potassium levels in guard cells (D) movement of water from neighbouring cells into guard cells (E) guard cells becoming flaccid (a) A and E only (b) B, C and D only (c) A, C and D only (d) B, D and E only (e) C and E only 132. Na+ / K+ pump in a cell is an example of [AMU'10] (1) osmosis (2) diffusion (3) passive transport (4) active transport 133. Stomatal opening or closing is due to [AMU'10] (1) change in the turgidity of guard cells (2) the inner wall of each guard cell is thick and elastic. (3) cellulose microfibrils of guard cells are oriented radially. (4) All of the above

TRANSPORT IN PLANTS 134. Process of water exudation through hydathodes is known as [AMU'10] (1) guttation (2) transpiration (3) evaporation (4) bleeding 135. According to Steward’s starch hydrolysis theory, which one of the following is the principal reason for the opening of stomata during daytime? [Karnataka C.E.T'10] (1) Influx of K+ ions into guard cells under the influence of ABA hormone. (2) Conversion of sugar into starch in guard cells (3) Efflux of K+ ions from guard cells under the influence of ABA hormone. (4) Photosynthetic utilization of CO2 in guard cells. 136. Cell A and cell B are adjacent plant cells. In cell A ψs = – 20 bars and ψp = 8 bars. In cell B, ψs = – 12 bars and ψp = 2 bars. Then [Karnataka C.E.T 2010] (1) water moves from cell A to cell B. (2) there is no movement of water between cell A and cell B. (3) water moves from cell B to cell A. (4) equal amount of water is simultaneously exchanged between cell A and cell B. 137. Which one of the following is a driving force for the process of passive absorption of water in roots? [Karnataka C.E.T'10] (1) The increase in imbibitional pressure in root cells (2) Root pressure (3) Activity of aquaporions (4) Transpiration in leaves 138. Which of the following scientists proposed the mechanism of opening and closing of stomata related to the active K+ exchange? [C.O.M.E.D. - K'10] (1) Lloyd (2) Scarth (3) Sayer (4) Levitt 139. Transpiration-Cohesion tension theory operates in ........ [C.O.M.E.D. - K'10] (1) Active absorption (2) Active and passive absorption (3) Passive absorption (4) Apoplastic movement 140. Water absorption by root hairs occurs until [C.O.M.E.D. - K'10] (1) concentration of water in the cell sap is higher. (2) salt concentration in soil is higher. (3) they are separated from soil by a selectively permeable membrane. (4) water potential is lower 141. In a fully turgid cell the .......... is zero. [Orissa'10] (1) OP (2) WP (3) TP (4) DPD 142. Which of the following is not purpose of transpiration ? [Kerala'10] (1) Supplies water for photosynthesis. (2) Maintains shape and structure of plants. (3) Helps in translocation of sugar from source to sink. (4) Transports minerals from the soil to all parts of the plants.

481 143. Plasmolysis occurs when the cell is placed in [H.P.P.M.T'10] (1) isotonic solution (2) hypotonic solution (3) hypertonic solution (4) none of the above 144. Which is not related to transpiration pull? [M.H.T. C.E.T'10] (1) Capillarity (2) Adhesion (3) Cohesion (4) Ascent of sap 145. Stomata open in response to [M.H.T. C.E.T'10] (1) decrease in O.P. (2) increase in osmotically active sugar (3) rise in K+ level (4) increase in water potential 146. Solute potential of a solution is always [D.P.M.T'10] (1) = 0 (2) < 0 (3) > 0 (4) between 0.1 to 1.0 147. Simultaneous movement of two molecules across a membrane in the same direction is known as [D.P.M.T'10] (1) antiport (2) uniport (3) symport (4) biport 148. A negative effect of transpiration is [Gujarat C.E.T'10] (1) development of water stress. (2) increase in mineral absorption. (3) maintenance of leaf temperature. (4) causing cooling. 149. Attraction of water molecules to polar surfaces is known as [Kerala PMT 2010] (a) cohesion (b) capillarity (c) surface tension (d) tensile strength (e) adhesion 150. Which of the following is not a purpose of transpiration? [Kerala PMT 2010] (a) Supplies water for photosynthesis (b) Helps in translocation of sugars from source to sink (c) Maintains shape and structure of the plants (d) Cools leaf surfaces (e) Transports minerals from the soil to all parts of the plant 151. When water enters in roots due to diffusion, it is termed as [BHU'06,11] (1) osmosis (2) passive absorption (3) active absorption (4) imbibition 152. “Active absorption of water by roots from the soil is mainly affected by [C.O.M.E.D-K’s.'11] (1) Tension in cell sap due to transpiration (2) Osmotic concentration of cell sap (3) Hydrophobic nature of root hair (4) Typical tissue organisation.

482 153. The first process by which water enters into the seed coat when a seed is placed in suitable environment for germination is [Karnataka C.E.T '07, UPCPMT'07, Orissa Jee'11] (1) absorption (2) imbibition (3) osmosis (4) active transport. 154. The root cap is not used in absorption of water due to [Orissa J.E.E'11] (1) presence of root hairs (2) absence of root hairs (3) its presence in elongation zone (4) None of these 155. Root pressure is due to [Orissa J.E.E'11] (1) passive transport (2) active transport (3) gravitation (4) None of these 156. Which one of the following is not related to guttation [K.C.E.T.'11] (1) Water is given out in the form of droplets. (2) Water given out is impure. (3) Water is given out during daytime. (4) Guttation is of universal occurrence. 157. The force responsible for upward conduction of water against gravity comes from [K.C.E.T.'11] (1) transpiration (2) translocation (3) respiration (4) photosynthesis 158. Stomatal opening is affected by [D.P.M.T.'11] (1) nitrogen concentration, carbon dioxide concentration and light. (2) carbon dioxide concentration, temperature and light. (3) nitrogen concentration, light and temperature. (4) carbon dioxide concentration, nitrogen concentration and temperature. 159. Which of the following is the most acceptable theory for movement of water through plants? [D.P.M.T.'11] (1) Cohesion theory (2) Passive transport (3) Root pressure (4) Capillarity 160. When a cell is plasmolysed, It becomes [J & K C.E.T.'11] (1) flaccid and its TP becomes zero. (2) turgid and its TP becomes zero. (3) turgid and TP becomes equal to OP. (4) flaccid and DPD becomes zero. 161. The factor most important in regulating transpiration is [J & K C.E.T.'11] (1) wind (2) temperature (3) light (4) relative humidity 162. Sunken stomata are usually found in [J & K C.E.T.'11] (1) phanerograms (2) insectivorous plants (3) C3 plants (4) CAM plants 163. The cause of opening or closing of the stomata mainly depends upon change in the turgidity of [H.P.P.M.T.'11] (1) microfibrils (2) guard cells (3) epidermal cels (4) xylem 164. The difference between osmotic pressure and turgor pressure is [Wardha'11] (1) DPD (2) transpiration pull (3) osmotic potential (4) solute potential

BIOLOGY 165. Opening of stomata is due to [Wardha'11] (1) Influx of K+ into guard cells. (2) Low pH of guard cells. (3) High osmolarity. (4) All the above. 166. One cell is kept in 1 m solution of sucrose and another cell in 1 M solution of NaCl. The water potential of the cells kept in [C.O.M.E.D-K’s.'11] (1) Sucrose solution will be greater (2) NaCl solution will be greater (3) Both will be equal (4) Sucrose solution will be lower and NaCl would be greater 167. Guttation is the result of : [CBSE PMT 2011M] (a) diffusion (b) transpiration (c) osmosis (d) root pressure 168. Two cells A and B are contigous. Cell A has osmotic pressure 10 atm, turgor pressure 7 atm and diffusion pressure deficit 3 atm. Cell B has osmotic pressure 8 atm, turgor pressure 3 atm and diffusion pressure deficit 5 atm. The result will be [JIPMER-2011] (a) movement of water from cell B to A (b) no movement of water (c) equilibrium between the two (d) movement of water from cell A to B 169. Select the correct statement. [Kerala PMT 2011] (a) absorption of water by seeds and dry wood is example of facilitated diffusion. (b) the apoplast is the system of interconnected protoplasts. (c) pinus seeds cannot germinate and establish without the presence of mycorrhizae. (d) the translocation in phloem is unidirectional whereas in the xylem it is bidirectional. (e) in plants, the water loss in its liquid phase is known as transpiration. 170. The process by which water is absorbed by solids like colloids causing them to increase in volume is called [Kerala PMT 2011] (a) osmosis (b) plasmolysis (c) imbibition (d) diffusion (e) facilitated diffusion. 171. Root hair absorbs water from soil through [JIPMER-2012] (a) turgor pressure (b) ion exchange (c) osmosis (d) DPD 172. A cell, when kept in sugar solution, gets dehydrated. Then solution is [AFMC 2012] (a) hypotonic (b) hypertonic (c) isotonic (d) none of these 173. If a stem is girdled [AIIMS 2012] (a) Root dies first (b) Shoot dies first (c) Both die together (d) None of the above would die

TRANSPORT IN PLANTS 174. Assertion : The antibodies separted from serum are homogenous. Reason : Monoclonal antibodies are homogenous immunological reagents. [AIIMS 2012] (a) If both Assertion and Reason are correct and Reason is the correct explanation of Assertion. (b) If both Assertion and Reason are correct, but Reason is not the correct explanation of Assertion. (c) If Assertion is correct but Reason is incorrect. (d) If Assertion is incorrect but Reason is correct. 175. The ability to rise in thin tubes and the ability to resist a pulling force are respectively referred to as [Kerala PMT 2012] (a) tensile strength and capillarity (b) adhesion and capillarity (c) cohesion and adhesion (d) cohesion and capillarity (e) capillarity and tensile strength 176. Consider the following statements with reference to facilitated transport. [Kerala PMT 2012] A. Requires ATP energy. B. Transport saturates. C. Highly selective. D. Requires special membrane properties. E. Uphill transport. Of the above statements (a) A, B and C are relevant but D and E are irrelevant (b) B, C and E are relevant but A and D are irrelevant (c) C, D and E are relevant but A and D are irrelevant (d) A, D and E are relevant but B and C are irrelevant (e) B, C and D are relevant but A and E are irrelevant 177. Which of the following is not a purpose of transpiration? [Kerala PMT 2012] (a) Helps in absorption and transport in plants. (b) Prevents loss of water. (c) Maintains shape and structure of plants by keeping the cell turgid. (d) Supplies water for photosynthesis. (e) Cools leaves surfaces. 178. Which of the following criteria does not pertain to facilitated transport? [AIPMT (NEET) 2013] (1) High selectivity (2) Transport saturation (3) Uphill transport (4) Requirement of special membrane proteins 179. Chamber A and B are separated by a semi-permeable membrane. Study the given figure and choose the right option. [Kerala PMT 2013]

483

180.

181.

182.

183.

184.

(a) Chamber A has higher water potential and water will move from A to B. (b) Chamber B has lower solute potential and water will move from A to B. (c) Chamber A has higher solute potential and water will move from B to A. (d) Chamber B has lower water potential and water will move from B to A. (e) Chamber B has higher solute potential and water will move from B to A. Select the matched ones. [Kerala PMT 2013] (i) Guttation - water loss in its liquid phase (ii) Adhesion - mutual attraction between water molecules (iii) Imbibition - absorption of water by dry wood (iv) Hypotonic solution - cells shrink (a) (i), (ii) and (iii) only (b) (ii) and (iv) only (c) (iii) and (iv) only (d) (ii), (iii) and (iv) only (e) (i) and (iii) only Assertion : During zygotene, chromosomes show bivalent stage. Reason : Bivalent is half the number of chromosomes. [AIIMS 2013] (a) If both Assertion and Reason are correct and Reason is the correct explanation of Assertion. (b) If both Assertion and Reason are correct, but Reason is not the correct explanation of Assertion. (c) If Assertion is correct but Reason is incorrect. (d) If Assertion is incorrect but Reason is correct. Assertion : Upward movement of water is called ascent of sap. Reason : Upward movement of water occurs through xylem and phloem. [AIIMS 2013] (a) If both Assertion and Reason are correct and Reason is the correct explanation of Assertion. (b) If both Assertion and Reason are correct, but Reason is not the correct explanation of Assertion. (c) If Assertion is correct but Reason is incorrect. (d) If Assertion is incorrect but Reason is correct. Water potential of pure water and its solution are [AIIMS 2013] (a) 0 and 1 (b) 0 and 0 (c) 0 and more than one (d) 0 and less than 1. The hydrostatic pressure developed within a plant cell through osmosis and/or imbibition when exerted on its wall is: [UPCPMT 2015] (1) Wall Pressure (2) Osmotic pressure (3) Suction pressure (4) Turgor pressure

484

BIOLOGY

EXERCISE - 3 | Test Yourself A RBC and a plant cell (with thick cell wall) are placed in distilled water. The solute concentration is the same in both the cells. What changes would be observed in them?

7.

(1) Both plant cell and RBC would not undergo any change.

After a few days, which of the following will have occurred?

(2) The RBC would increase is size and burst while the plant cell would remain about the same size.

(1) A rise in level X and a drop in level Y. (2) A drop in level X and a drop in level Y.

(3) The plant cell would increases in size and burst while the RBC would remain about the same size. (4) Both plant cell and RBC would decrease in size and collapse.

(3) A rise in level X and a rise in level Y. (4) A drop in level X and a rise in level Y. 8.

ot sp og

Pressure Potential (MPa) 0.44 0.34 0.27

m

A B C

Osmotic Potential (Mpa) –0.87 –0.92 –0.68

bl

Cell

.c

The osmotic potential and pressure potential of three cells (A, B, C) located in different parts of an actively transpiring plant are given below.

Based on Munch’s pressure-flow hypothesis, which of the following conditions would increase the rate of translocation?

y.

2.

Refer the experiment given below

om

1.

(4) B, C, A

Which of the following helps in the absorption of water and mineral salts? (2) Anabaena

ed

(1) Mycorrhiza (3) Nostoc

(4) None of these

By which of the following active uptake of water is affected?

m

4.

ca

(3) C, A, B

la

(2) A, C, B

ic a

3.

(1) A, B, C

de

Identify these three cells as root hair, root cortical and leaf mesophyll cells respectively.

(1) An increase in the humidity in the outside air. (2) A decrease in phloem unloading at the sink.

ee t

(1) Transpirational power of the root hairs. (2) Typical tissue organization.

(3) An increase in sucrose production at the source.

//n

(3) Tension due to transpiration. When different types of molecules in a fluid move together in response to a pressure gradient, this is called

tp

5.

s:

(4) Osmotic concentration of the cell sap of the leaves.

(2) facilitated diffusion

(3) joined response

(4) pressured movement

ht

(1) bulk flow

6.

Ringing experiment is related with (1) ascent of sap (2) translocation of food (3) mineral nutrition (4) Both (1) & (2)

(4) A decrease in photosynthesis. Direction (Q. 9 to 11) : In the following questions, more than one of the answers given may be correct. Select the correct answer & mark them according to the codes given below. Codes : (1)

a, b & c are correct.

(2) a & b are correct.

(3)

b & d are correct.

(4) a & c are correct.

9.

Diffusion pressure in directly proportion to (a) concentration

(b) density of particles

(c) temperature

(d) mass of particles.

TRANSPORT IN PLANTS 10.

11.

485

The properties, which make xylem suitable for the long distance transport of water & solutes are (a) no living content is so less resistance to flow. (b) tubes are rigid so do not collapse. (c) five tubes are necessary to prevent water columns from collapsing. (d) long tubes are formed by collapsing short tubes.

16.

(1) They increase the speed of transport across a membrane. (2) They concentrate solute molecules on one side of the membrane.

Stomatal movement is affected by

(3) They have specific binding sites for molecules they transport.

(a) CO2 concentration (b) growth hormone (c) atmospheric humidity(d) day length. 12.

At the endodermis, water movement through the apoplast pathway is obstructed by which alphabet? Endodermis A

Which of the following is not true of the carrier molecules involved in facilitated diffusion?

(4) They may undergo conformational change upon binding of solutes. 17.

Study the figure in which two chambers, A & B containing solutions are separated by a semi-permeable membrane.

Symplastic path

Solute molecules

Water

Apoplastic path

13.

14.

15.

B D

C Pericycle

Semi-permeable membrane

(1) A (2) B (3) C (4) D If turgor pressure becomes equal to osmotic pressure (1) water leaves the cell. (2) water enters the cells. (3) no exchange of water takes place. (4) solute pass out of the cell. Match the terms of column I with the appropriate terms of column II. (i)

Column I K+ pump theory

(a)

(ii) (iii) (iv) (v)

Plasmolysis Imbibition Guttation Osmosis

(b) (c) (d) (e)

Column II Semi-permeable membrane Hydathodes Stomatal movement Exosmosis Hydrophilic colloids

(1) (i)-(c); (ii)-(d); (iii)-(e); (iv)-(b); (v)-(a) (2) (i)-(a); (ii)-(b); (iii)-(c); (iv)-(d); (v)-(e) (3) (i)-(b); (ii)-(c); (iii)-(e); (iv)-(a); (v)-(d) (4) (i)-(d); (ii)-(e); (iii)-(b); (iv)-(c); (v)-(a) Which of the following statements are true for diffusion? (I) It is a fast process. (II) It depends on a living system. (III) It is very important to plants since it is the only means for gaseous movement within the plant body. (IV) The rate of diffusion of gases is faster than liquid or solutes. (1) All are correct. (2) Only II is correct. (3) I and II are correct. (4) III & IV are correct.

Identify the incorrect statement. (1) Movement of solvent molecules will take place from chamber A to B. (2) Movement of solute will take place from chamber A to B. (3) Presence of a SPM is a prerequisite for this process to occur. (4) The direction and the rate of osmosis depend upon both the pressure gradient and concentration gradient 18.

Which of the following is true about apoplast (the transport route through intercellular spaces and cell wall)? (1) Cell membrane is involved. (2) Minerals movement is regulated by membranes. (3) Plasmodesmata are involved. (4) Water and solutes can move by bulk flow.

19.

Which one of following statement is incorrect? (1) Movement through the apoplast does not involve crossing the cell membrane. (2) Water is absorbed along with mineral solutes, by the root hairs, purely by diffusion. (3) Apoplastic movement is dependent on the gradient. (4) Symplast is the system of adjacent cell wall.

20.

As various ions from the soil are actively transported into vascular tissues of root. Water follows and increases the pressure inside the xylem. This positive pressure is called (1) mass pressure

(2) root pressure

(3) osmotic potential (4) None of those

486 21.

22.

23.

24.

25.

26.

27.

BIOLOGY Which of the following is a difference between transport by xylem and transport by phloem? (1) Active transport moves xylem but not phloem sap. (2) Transpiration moves phloem sap but not xylem sap. (3) Xylem sap moves up; phloem sap moves up and down. (4) Xylem moves from sugar source to sink but phloem does not. Which of the following is not a part of the transpiration cohesion – adhesion mechanism of ascent of sap? (1) The loss of water from the mesophyll cells, which initiate a pull of water molecules from the neighboring cells. (2) Hydrophilic wall of narrow tracheids and xylem vessel that help to raise the column of water against the force of gravity. (3) Reduction of water potential in the surface film of mesophyll due to transpiration. (4) The active pumping of water into the xylem of root. Which of the following plant factors affects transpiration? (1) Number and distribution of stomata, number of open stomata, temperature. (2) Temperature, light, humidity, wind speed. (3) Canopy structure, water status of plant, number and distribution of stomata and number of stomata open (%). (4) Canopy structure, number and distribution of stomata and humidity of air. Arrange the following events in a correct order that explains the mass flow of materials in the phloem? (A) Water diffuses into the sieve tube elements. (B) Leaf cells produce sugar by photosynthesis. (C) Solutes are actively transported into the sieve elements. (D) Sugar is transported from cell to cell in the leaf. (E) Sugar moves down the stem. (1) B-D-C-A-E (2) B-D-A-C-E (3) A-B-C-D-E (4) D-B-A-C-E A cell is plasmolysed after being kept in a hypertonic solution. What will be present between cell wall and plasmalemma? (1) Isotonic solution (2) Hypertonic solution (3) Both (1) and (4) (4) Hypotonic solution Water will be absorbed by root hairs when (1) concentration of salt in the soil is high. (2) concentration of solutes in the cell sap is high. (3) plant is rapidly respiring. (4) they are separated from soil by a permeable membrane. Who proposed that the upward and downward movement of materials take place? (1) Sacks (2) Boehm (3) Dixon (4) Curtis

28.

29.

30.

31.

32.

33.

Addition of a solute to pure water causes (1) negative water potential. (2) more negative water potential. (3) positive water potential. (4) more positive water potential. Water will move from the root hairs through cortex if the water potentials are (1) root hairs = 0; Cortex = 0; Xylem = 0 (2) root hairs = 0; Cortex = – 1; Xylem = –2 (3) Root hairs = –2; Cortex = –1; Xylem = 0 (4) root hairs = 0; Cortex = + 1; Xylem = + 2 All the statements are correct except (1) mycorrhizal fungi form a network around the young root and they penetrate the root cells. (2) mycorrhizae helps the plant to absorb water and minerals. (3) root provides sugar and nitrogenous organic compounds to the mycorrhizae. (4) Pinus seed can germinate and establish without mycorrhizae. According to the pressure flow model, during fruit development, photosynthesizing leaves would be the ......... and the fruit would be ................ . (1) sink, sink (2) sink, source (3) source, sink (4) source, source What mechanism explains the movement of sucrose from source to sink ? (1) Evaporation of water and active transport of sucrose from sink. (2) Osmotic movement of water into the sucrose loaded sieve tube cells creating a higher hydrostatic pressure into the source than in the sink. (3) T Tension created by differences in hydrostatic pressure in the source and sink. (4) Active transport of sucrose through the sieve tube membranes driven by proton pump. Which the following shows the correct explanation of the given figures? Pure Water

Very salty H2O

Salty water

Cell

Cell

Cell

A

B

C

(1) Cell “A” will lose H2O, Cell “B” will gain H2O, Cell “C” neither gain nor loses H2O. (2) Cell “A” neither gain nor loses H2O, Cell “B” will gain H2O, Cell “C” will lose H2O. (3) Cell “A” will gain, Cell “B” neither gain nor loses H2O, Cell “C” lose H2O. (4) Cell “A” will gain H2O, Cell “B” will lose H2O, Cell “C” neither gain nor loses H2O.

TRANSPORT IN PLANTS

38.

39.

(1) Passive absorption (2) Active absorption (3) Root absorption 40.

41.

(4) Salt absorption

In many thin leaved mesophytes the stomata open during the day time and close at night. This comes under (1) Alfalfa type

(2) Potato type

(3) Bean type

(4) Barley type

What are aquaporins ? (1) Cytoplasmic connections between cortex cells.

0.1

(4) Water W specific channels in membranes that may regulate the rate of osmosis.

time/min

0

pressure/MPa

– 0.1

Q R

– 0.2

What are the correct labels for the graph? P

43.

Q

R

(1) (2)

ψ

ψp

ψs

ψ

(3)

ψs

ψp

ψp

ψ

ψs

ψp

ψs

ψ

(4)

The diagram below represents those parts of a plant which are associated with the transfer of materials during day light. D to atmosphere A E

B root hair cell

storage cell root cells

C

44.

Which one of the arrow indicates mass flow of organic solutes ? (1) A (2) B and C (3) D (4) E Which one of the following graphs most closely represents the relationship between the rate of transpiration of a mesophytic leaf and the atmospheric humidity ?

(1)

(2) Openings in the lower epidermis of leaves through which water vapor escapes (3) Openings into root hairs through which water enters

P

rate of transpiration

37.

The graph shows the relationship between ψ (water potential), ψs(solute potential) and ψp (pressure potential) for a plant cell placed in pure water. 0.2

relative humidity/%

(2)

(3)

relative humidity/%

(4)

relative humidity/%

rate of transpiration

36.

42.

rate of transpiration

35.

In part A of a plant, sugars are actively transported into the phloem tissue. In part B, sugars are actively transported out of the phloem. Which way will the phloem sap move under these conditions? (1) From A to B. (2) From B to A. (3) First from A to B; then, once the pressure builds up, from B to A. (4) First from B to A; then, once the pressure builds up, from A to B. Which of the following characteristics applies to both xylem and phloem transport ? (1) Follows a water potential gradient (2) Involves only living cells (3) Can occur in both directions (4) Involves active transport of solute with passive movement of water. Which of the following cell types would be the third cell type a sugar molecule is likely to encounter on its route from its site of production in a chloroplast to its site of storage in the root ? (1) Mesophyll cell (2) Companion cell (3) Sieve tube element (4) Parenchyma The productivity of a crop declines when leaves begin to wilt mainly because (1) the chlorophyll of wilting leaves decomposes. (2) flaccid mesophyll cells are incapable of photosynthesis. (3) stomata close, preventing CO2 from entering the leaf. (4) photolysis, the water-splitting step of photosynthesis, cannot occur when there is a water deficiency. Imagine cutting a live twig from a tree and examining the cut surface of the twig with a magnifying glass. You locate the vascular tissue and observe a growing droplet of fluid exuding from the cut surface. This fluid is probably (1) phloem sap (2) xylem sap (3) guttation fluid (4) fluid of the transpiration stream Which one of the following is a rapid type of absorption?

rate of transpiration

34.

487

relative humidity/%

488 45.

BIOLOGY In cells A, B, C, D potentials are as given below. Cell A B C D

46.

47.

Solute potential – 15.0 bars – 25.0 bars – 30.0 bars – 35.0 bars

Pressure potential 5.0 bars 15.0 bars 20.0 bars 25.0 bars

Water will move from (1) A to B (2) B to A (3) A to B to C to D (4) Remain stationary Transpiration rate is measured in an apple plant on both surfaces of leaves. It will be higher on (1) lower surface (2) upper surface (3) None of the two surface (4) Both (1) and (2) What facilitates the movement of K+ into epidermal cells of the root ? (1) Cotransport through a membrane protein. (2) Bulk flow of water into the root. (3) Passage through selective channels, aided by the membrane potential created by proton pumps. (4) Active transport through a potassium pump.

48.

Which of the following regulates stomatal opening and closing ? (1) Abscisic acid levels (2) Light levels (3) Carbon dioxide concentrations (4) All of the above 49. Proton pumps in the plasma membranes of plant cells may (1) generate a membrane potential that helps drive cations into the cell through their specific carriers. (2) be coupled to the movement of K+ into guard cells. (3) drive the accumulation of sucrose in sieve-tube members. (4) be involved in all of the above 50. If the external solution balances the osmotic pressure of cytoplasm, it is said to be (1) isotonic (2) hypotonic (3) atonic (4) hypertonic

TRANSPORT IN PLANTS

489

ANSWER KEY EXERCISE 1 : NCERT BASED QUESTIONS 1. 6. 11. 16. 21.

(3) (2) (3) (3) (2)

2. 7. 12. 17. 22.

(2) (3) (1) (2) (2)

3. 8. 13. 18. 23.

(2) (3) (2) (2) (2)

4. 9. 14. 19. 24.

(4) (4) (3) (4) (4)

5. 10. 15. 20. 25.

EXERCISE 3 : TEST YOURSELF (1) (1) (4) (3) (3)

1.

(2)

2.

5. 6.

(3) Water potentials of the given cells are Ψw = Ψs + Ψp A = – 0.87 + 0.44 = – 0.43 B = – 0.92 + 0.34 = – 0.58 C = –0.68 + 0.27 = – 0.41 As water moves from greater water potential to less, root hair, root cortical and leaf mesophyll cells are C,A,B respectively. (1) In mycorrhiza, fungal members help in absorption of mineral and water. (3) The rate of absorption of water is almost directly proportional to the rate of transpiration. (1) (4) 7. (1) 8. (3) 9. (4) 10. (1)

11.

(1)

13.

14.

(3) Movement of water (solvent) depends on diffusion pressure deficit, which is D.P.D = O.P – T.P If O.P. = T.P. So D.P.D = O So no movement takes place. Water moves towards low D.P.D to high D.P.D. (1)

15.

(4)

EXERCISE 2 : WINDOW TO COMPETITIVE EXAMS 1. 6. 11. 16. 21. 26. 31. 36. 41. 46. 51. 56. 61. 66. 71. 76. 81. 86. 91. 96. 101. 106. 111. 116. 121. 126. 131. 136. 141. 146. 151. 156. 161. 166. 171. 176. 181.

(3) (3) (4) (4) (2) (2) (1) (2) (4) (3) (3) (2) (1) (4) (1) (2) (1) (2) (1) (4) (2) (2) (2) (2) (1) (2) (2) (3) (4) (2) (1) (4) (2) (1) (3) (5) (2)

2. 7. 12. 17. 22. 27. 32. 37. 42. 47. 52. 57. 62. 67. 72. 77. 82. 87. 92. 97. 102. 107. 112. 117. 122. 127. 132. 137. 142. 147. 152. 157. 162. 167. 172. 177. 182.

(4) (2) (1) (4) (4) (4) (1) (1) (3) (2) (2) (4) (3) (2) (2) (3) (1) (1) (3) (3) (3) (3) (4) (2) (1) (1) (4) (4) (3) (3) (2) (1) (4) (4) (2) (2) (3)

3. 8. 13. 18. 23. 28. 33. 38. 43. 48. 53. 58. 63. 68. 73. 78. 83. 88. 93. 98. 103. 108. 113. 118. 123. 128. 133. 138. 143. 148. 153. 158. 163. 168. 173. 178. 183.

(1) (2) (2) (2) (3) (1) (4) (2) (3) (2) (3) (1) (4) (1) (2) (3) (3) (2) (2) (2) (2) (3) (1) (2) (2) (4) (4) (4) (3) (1) (2) (4) (2) (4) (1) (3) (4)

4. 9. 14. 19. 24. 29. 34. 39. 44. 49. 54. 59. 64. 69. 74. 79. 84. 89. 94. 99. 104. 109. 114. 119. 124. 129. 134. 139. 144. 149. 154. 159. 164. 169. 177. 179. 184.

(3) (3) (2) (3) (2) (1) (2) (1) (3) (2) (1) (1) (2) (2) (2) (3) (4) (1) (2) (3) (1) (2) (2) (4) (1) (1) (1) (3) (1) (5) (2) (1) (1) (3) (4) (1) (4)

5. 10. 15. 20. 25. 30. 35. 40. 45. 50. 55. 60. 65. 70. 75. 80. 85. 90. 95. 100. 105. 110. 115. 120. 125. 130. 135. 140. 145. 150. 155. 160. 165. 170. 175. 180.

(3) (1) (4) (4) (4) (1) (3) (2) (1) (3) (3) (2) (1) (3) (2) (3) (2) (3) (3) (1) (4) (2) (3) (1) (4) (d) (4) (4) (3) (2) (2) (1) (4) (3) (5) (5)

3. 4.

16. 18.

12.

(2)

Diffusion is a slow process and it does not depend on a living system. (2) 17. (2)

19. 20.

(4) The apoplastic movement of water occurs exclusively through the intercellular spaces & walls of the cells. The apoplast does not provide any barrier to water movement and water movement is through mass flow. (4) Symplast is the system of interconnected protoplasts. (2)

21.

(3)

25.

(2) During plasmolysis, plasma membrane shrink along with cytoplasm, so by open pores of cell wall hypertonic solution will be filled between cell wall and plasma membrane. (2) The absorption of water still occurs when concentration of outer soil water is more than root hair cell sap. (4) According to Curtis upward conduction of food also takes place through phloem. This view is based upon ringing experiments.

26. 27.

22.

(4)

23.

(3)

24.

(1)

490 28.

29. 31. 34.

35. 36.

37. 39.

40.

BIOLOGY (1) The pure water, at atmospheric pressure has zero water potential. The addition of any solute particles reduces the free energy of water. Thus, the water potential will be negative. (2) 30. (4) (3) 32. (2) 33. (4) (1) Sap will flow from high to low pressure areas in the plant. Adding sugars to the sap causes water to enter the phloem, thus increasing pressure. Removing sugars causes water to leave the phloem, thereby reducing pressure. (1) Choices b, c, and d are true for phloem transport only. (3) Sugar molecules diffuse through the symplast of mesophyll cells, are pumped into the apoplast near a vein, re-enter the symplast of a companion cell, and then move into a sieve tube element. (3) 38. (1) (1) In actively transpiring plants absorption of water takes place due to the forces developed at the transpiring surface of the plant, i.e., transpiration pull. In this type the cells of the root do not play any part, hence it is known as passive absorption. This is the most common & rapid method of water absorption. (1) In many thin leaved mesophytes the stomata open during the day time and close at night. This comes under alfalfa type.

41.

(4)

42.

(3) Pure water has the highest water potential as zero. As water enters the cells, solute potential becomes less negative and the pressure potential is usually positive. As water enters the cell, the volume of protoplast increases, causing the pressure potential to rise from zero MPa. (4) The palisade cells in the leaf contain chlorophyll which can capture light energy to manufacture organic solutes through photosynthesis. These organic nutrients are then transported via the phloem to other parts of the plant. (2) With increasing humidity, the rate of transpiration decreases linearly, because the high saturation of water vapour in the atmosphere prevents the evaporation of more water from the leaf interior to the exterior. (4) Water potentials of all the four cells are equal. (1) Stomata are found only on lower surface. (3) (4) Abscisic acid, light, and carbon dioxide levels all regulate stomatal opening and closing. (4) 50. (1)

43.

44.

45. 46. 47. 48. 49.

12

Chapter

Mineral Nutrition At a Glance

While going through the chapter pay special attention to the following – Terms and definitions – (1) Tank farming, (2) Critical concentration, (3) T Toxic concentration. Flow charts – 1.

 

Introduction



Essential Mineral Elements



Division of essential elements



Tables –



1.

Role of essential elements

2.

Deficiency symptoms and its causing elements

  



All living organisms require macromolecules like carbohydrates, proteins, fats and minerals for the development.



Various chemical substances that provide nourishment to living organism are called nutrients.



In addition to carbon, hydrogen and oxygen plants require a variety of mineral elements for their survival.

  

Methods to study the mineral requirements of plants

Major role of nutrients

Mechanism of absorption of Elements Translocation of Solutes

Soil as reservoir of essential elements Metabolism of Nitrogen

 



Division of essential elements

Nitrogen cycle

Biological nitrogen �ixation

Types of Nutrition in Plants

Connecting Concepts

 Aeroponics is a system of growing Absorption of minerals and their utilization by plant is called mineral nutrition. plants with their roots bathed in Only the green plants (called autotrophs) can prepare their own food from simpler nutrient mist (a cloud of moisture in substances, rest of the living organisms depend on them directly or indirectly for food. air). The rooted plants are placed in a All non-green plants and animals including human beings are heterotrophs. Autotrophic special type of boxes with their shoot green plants obtain their nutrition from inorganic substances present in soil in the form of exposed to air and roots inside the box bearing nutrient mist. minerals, known as mineral elements or mineral nutrients.

METHODS TO STUDY THE MINERAL REQUIREMENT OF PLANTS 

In 1860, Julius von Sachs, a prominent German botanist, demonstrated for the first time that plants could be grown to maturity in a defined nutrient solution in complete absence of soil. This technique of growing plants in a nutrient solution is known as hydroponics or soilless growth.



After a series of experiments in which the roots of the plants were immersed in nutrient solutions and wherein an element was added/ removed or given in varied concentration, a mineral solution suitable for the plant growth was obtained.



By this method, essential elements were identified and their deficiency symptoms discovered.



Hydroponics has been successfully employed as a technique for the commercial production of vegetables such as tomato, seedless cucumber and lettuce.

 The method has been successfully used in growing Citrus and Olive.  Sand culture : Here plants are grown in inert sand + nutrient solution. Main advantage is that roots get natural environment and proper aeration.

492

BIOLOGY 

It must be emphasised that the nutrient solutions must be adequately aerated to obtain the optimum growth.

Funnel for adding water and nutrients

Cotton

Aerating tube

Nutrient solution Fig. 12.2 Hydroponic is a technique of plant production in which plants grown in a tube filled with nutrient solution circulating by pump and  returns to the reservoir due to gravity. Inset shows a plant’s roots bathed in aerated nutrient solution. 





Connecting Concepts

Fig. Diagram of a typical set-up for Fig. 12.1 Diagram of a typical set-up for nutrient nutrient solution culture solution culture

Because the plants are grown in large tanks, the process of soilless cultivation is also called as tank farming. Hydroponic culture solution was first prepared by Knop. The famous nutrient solutions are Knop solution, Hoagland solution, Arnon’s solution and Sach’s solution Hydroponic or soilless culture helps in knowing– •

the essentiality of mineral nutrients.

•

the deficiency symptoms developed due to non-availability of particular nutrients.

•

toxicity of plant when element is present in excess.

•

the possible interaction among different elements present in plants.

•

the role of essential elements in the metabolism of plants.

Hydroponic is useful in areas having thin, infertile and dry soils. They conserve water, can regulate pH optimum for a particular crop, control pests and disease, avoid problems by weeding, reduces labour cost etc.

ESSENTIAL MINERAL ELEMENTS

 Ash analysis: The plant tissue is  subjected to a very high temperature (550-600°C) in an electric muffle furnace and is reduced to ash. The plant ash left behind forms a very small proportion of plants dry weight ranging  from 2 to 10% only. Analysis of plant ash shows that about 92 mineral elements  are present in different plants. Out of these 30 elements, 16 elements are necessary for plants and are called essential elements.



Essential mineral elements are those elements which are required by plants for normal growth and development and without which plants cannot complete their life cycle. E.g. C, H, O, N, P, K, S, Mg, Ca, Fe, B, Mn, Cu, Zn, Mo, Cl. Elements which are present in a plant body and are not so required by plants are called non-essential elements. E.g. Na, Si, Al, Se, Sr, V. The criteria for essentiality of an element are given below: •

The element must be absolutely necessary for supporting normal growth and development. In the absence of the element the plants do not complete their life cycle or set the seeds.

•

The requirement of the element must be specific and not replaceable by any element.

•

The element must be directly involved in the metabolism of plants.

•

Out of 105 elements discovered so far only 20 elements have been found to be essential for plant growth and development.

Criteria of essentiality was proposed by Arnon and Stout and are popularly known as Arnon’s criteria of essentiality.

Function

Mostly involved in the functioning of enzymes, cofactors or metal activators. E.g. copper, molybdenum, zinc, boron, chlorine, nickel, manganese.

–

–

Essential elements that alter the osmotic potential of a cell E.g. Potassium plays an important role in the opening and closing of stomata.

2. Zn2+ is an activator of alcohol dehydrogenase and Mo of nitrogenase during nitrogen metabolism.

1. Mg 2+ activates ribulose bisphosphate carboxylase, oxygenase and phosphoenol pyruvate carboxylase.

Essential elements that activate or inhibit enzymes E.g

Essential elements as components of energy related chemical compounds E.g. Mg in chlorophyll, Phosphorous inATP.

Essential elements as components of biomolecules E.g. C, H, O, N.

Divided into four categories

Needed by plant body in relatively small amounts or trace amount (equal or less than 0.1 mg per gram dry matter).

Micro nutrients –

Secondary nutrients E.g. Ca, Mg, S

Macro nutrients broken down into 2 groups

amounts (10 m mole kg –1 of dry matter). Usually involved in the synthesis of organic molecules and development of osmotic potential. E.g. Carbon, hydrogen, oxygen, nitrogen phosphorus, sulphur, potassium, calcium, magnesium and iron. Oxygen is the most abundant element in the plant body as well as in other organism. Of these, C, H and O are mainly obtained from CO2 and H2O while others are absorbed from soil as mineral nutrition.

Needed by plant body in large

Primary nutrients E.g. N, P, K

–

–

–

–

–

Macro nutrients

Quantity

Divided on the basis of

Essential Elements

Flow chart : Division of Essential Elements

MINERAL NUTRITION 493

494

BIOLOGY

Major role of nutrients 

Check Point (i)

(ii)

(iii) (iv) (v)

(vi)

The practice of growing plants in nutrients enriched water without soil is called __________. The system of growing plants with their roots bathed in nutrient mist (a cloud of moisture in air) is called __________. Soilless culture was demonstrated by __________ in 1860. Plants which synthesize their own food is called __________. Ultilization of various absorbed ions by a plant for its growth and development is called __________. The essential elements which are required by plants in large amounts are called __________ and those required in very small amount by the plants are called __________.

S. no.

1.

Various elements perform the following major roles in the plants, like V • Construction of the plant body : The elements particularly C, H and O construct the plant body entering into the constitution of cell wall and protoplasm. They, are therefore, referred to as framework elements. Besides, these (C, and O) N, N P and S, Mg and Fe also enter in the constitution of protoplasm. They are, described as protoplasmic elements. • Maintenance of osmotic pressure : Various minerals present in the cell sap in organic or inorganic form maintain the osmotic pressure of the cell. • Maintenance of permeability of cytomembranes : The minerals, particularly Ca++, K+ and Na+ maintain the permeability of cytomembranes. • Influence of pH of the cell sap : Different cations and anions influence on the pH of the cell sap. • Catalysis of biochemical reaction : Several elements particularly Fe, Ca, Mg, Mn, Zn, Cu, Cl act as metallic catalyst in biochemical reactions. • Toxic effects : Minerals like Cu, As, etc. impart toxic effect on the protoplasm under specific conditions. • Balancing function : Some minerals or their salts act against the harmful effect of the other nutrients, thus balancing each other. Table 12.1: Role of essential (macro & micro) element and their deficiency symptoms. Name of element (location)

Form in Functions which they are absorbed Nitrogen NO2–, Major constituent of (Required in large NO3– or proteins, nucleic acids, amount, especially NH4+ vitamins and minerals. in growing parts of plants)

2.

Phosphorous (Young tissues, withdrawn from the older metabolically less active cells)

3.

Potassium (Abundant in meristematic tissues, buds, leaves and root tips)

In the (i) Constituent of cell form of membrane, nucleic phosphate acids, nucleotides and ions some proteins. – (H2PO4 , (ii) Required for all or phosphorylation 2– HPO4 ) reactions. K+

(i) Determine cationanion balance in cell. (ii) Involved in protein synthesis, closing & opening of stomata. (iii) Activation of enzyme. (iv) Maintenance of turgidity of cells.

Deficiency symptoms

Chlorosis (loss of chlorophyll and yellowing of leaves), stunting of plants, dormancy of lateral buds, inhibition of cell division, late flowering, purple colouration of shoot axis, wrinkling of cereal grains. Delay in seed germination, reduced growth, purple or red spots on leaves, dark green leaves, premature fall of leaf and flower buds. Scorched leaf tips, shorter internodes, chlorosis in interveinal, loss of apical dominance, loss of cambial activity, plastid disintegration, increased rate of respiration.

MINERAL NUTRITION 4.

Calcium [Required by meristematic tissue and differentiating tissue. Used in mitotic spindle during cell division.]

495 Ca2+ (Calcium ions)

(i) (ii)

(iii) (iv) (v)

5.

Magnesium divalent (All the leaves Mg2+ of the plants, withdrawn from ageing leaves and directed to developing seeds).

6.

Sulphur SO42– (Stem and root tips, young leaves, Remobilized during senescence)

7.

8.

Involved in normal functioning of cell membrane. Activate certain enzymes and regulates metabolic activities. Used in synthesis of cell wall (middle lamella). Help to stabilize the structure of the chromosomes. Conversion of toxic oxalic acid to calcium oxalate.

Stunted growth, necrosis (death of tissue) of meristematic regions, chlorosis along the margins of young leaves, wither tip disease, premature flower abscission, blossoms end rots of tomato.

(i) Activate enzymes in respiration, photo -synthesis, DNA and RNA synthesis. (ii) Constituents of the porphyrin ring of chlorophyll structure. (iii) Maintain ribosome structure. (i) Constituent of amino acids like cystine and methionine. (ii) Main constituent of several coenzymes, vitamins (thymine, Co-A and ferredoxin, biotin) (iii) It is also, the component of allyl sulphide (onion, garlic) and sinigrin (mustard).

Chlorosis between leaf veins, necrosis on older leaves. Premature leaf abscission, reduced growth.

Iron Fe3+ (Required in (ferric larger amounts ions) than other micronutrients, in leaves and seeds)

(i)

Chlorosis-initiates in intravenous regions and then in the complete leaf, growth reduced, inhibition of chloroplast formation.

Manganese Mn2+ (All tissues collect along the leaf veins)

(i)

(ii) (iii) (iv)

(ii)

Constituent of ferredoxin and cytochromes. Involves in electron transfer. Activates catalase Helps in formation of chlorophyll. Necessary for photo -lysis of water. Activate enzymes involved in photosynthesis, respiration and N2 metabolism.

Chlorosis of younger leaves, stunted growth, anthocyanin accumulation, leaf curl, less juice content in citrus, yellow disease of tea, marsh spots (peas).

Interveinal chlorosis, grey spots on leaves, legume, cotyledons with brownish spot (marsh spot disease).

496

BIOLOGY Zinc (All tissues)

Zn2+

10. Copper (All tissues)

Cu2+

11. Boron (Leaves and seeds)

BO33– and B4O72–

9.

12. Molybdenum MoO22+ (All tissues, particularly in roots)

13. Chlorine (All tissues)

Cl– (Chloride ions)

(i)

Activates various enzymes like carboxy-lases. (ii) Necessary for synthesis of auxin. (i) Essential for overall metabolism in plants. (ii) Associated with certain enzymes involved in redox reactions. Necessary for uptake and utilization of Ca2+, membrane function, pollen germination, cell elongation, cell differentiation, carbohydrate translocation.

(i) Essential component of several enzymes like nitrogenase and nitrate reductase. (ii) Involved in nitrogen metabolism including nitrogen fixation. (i) Determine solute concentration (with Na+ and K+) and anion-cation balance in cells. (ii) Required for cell division in leaves and roots. (iii) Essential for photolysis of water.

Malformed leaves, interveinal chlorosis, stunted growth, white bud (maize) and sickle leaf of Cocoa. Tip necrosis of young leaves (e.g. citrus). In fruit trees, shoot die back, leaves fall off, bark becomes rough and splits. Death of root and shoot tips, loss of apical dominance, abscission of flowers, small size of fruits, absence of root nodules in leguminous plants, stunted growth. Drought rot of apples and water core in turnip, disintegration of internal tissues leading to brown heart disease of beets and top sickness of tobacco. Mottled chlorosis with marginal necrosis, infolding lamina or upper half of lamina fall down (whiptail disease in cauliflower and scald of beans) Bronze colour in leaves, leaf wilting, chlorosis, necrosis, reduce fruiting.

Deficiency symptoms of essential elements 

The concentration of the essential element below which plant growth is retarded is termed as critical concentration.



The element is said to be deficient when present below the critical concentration.



Since each element has one or more specific structural or functional role in plants, in the absence of any particular element, plants show certain morphological changes. These morphological changes are indicative of certain element deficiencies and are called deficiency symptoms.

MINERAL NUTRITION 

The deficiency symptoms vary from element to element and they disappear when the deficient mineral nutrient is provided to the plant. However, if deprivation continues, it may eventually lead to the death of the plant.



The parts of the plants that show the deficiency symptoms also depend on the mobility of the element in the plant.



For element that are actively mobilised within the plants and exported to young developing tissues, the deficiency symptoms tend to appear first in the older tissues. For example, nitrogen, potassium and magnesium are visible first in the senescent leaves. In the older leaves, biomolecules containing these elements are broken down, making these elements available for mobilising to younger leaves.



The deficiency symptoms tend to appear first in the young tissues whenever the elements are relatively immobile and are not transported out of the mature organs, for example, sulphur and calcium.

Toxicity of micronutrients 

In higher amount, micronutrients become toxic. Mineral ion concentration which reduces dry weight of tissue by 10% is called toxic concentration.



Critical toxic concentration varies for different micronutrients as well as different plants.



For example, Mn2+ is toxic beyond 600 µg g–1 for Soyabean and beyond 5300 µg g–1 for Sunflower. Toxic effects may be due to direct excess of the micronutrient or its interference in the absorption and functioning of other nutrients. Manganese toxicity (brown spots surrounded by chlorotic veins) is due to (i) Reduction in uptake of iron and magnesium. (ii) Inhibition of binding of magnesium to specific enzymes. (iii) Inhibition of calcium translocation into shoot apex. Therefore, excess of manganese causes deficiency of iron, magnesium and calcium. The toxicity symptoms of Mn are actually combined deficiency symptoms of Fe, Mg and Ca.

Table 12.2 : Deficiency symptoms and the mineral elements whose deficiency causes these symptoms are given below Deficiency symptoms 1.

2.

3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13.

Mineral elements whose deficiency causes these symptoms Chlorosis (loss of non-development N, K, Mg, S, Fe, Mn, Zn, Mo of chlorophyll causing yellowing of leaves). Stunted plant growth (retardation of N, K, Ca, S, Zn, B, Mo, Cl growth resulting rosette appearance of the plant) Purple colouration of shoot axis/leaves N, P, Mg, S, Mo Necrosis of leaves (localised death of Ca, Mg, Cu, K leaf tissue) Premature fall of leaves/buds P, Mg, Cu Inhibition of cell division N, K, S, Mo Wrinkling of cereal grains, dormancy of N, S, Mo lateral buds, and late flowering Die back of stem/leaves K, Cu Wilted leaves Cl Death of root and shoot tips B Bushy habit of shoot, K Scorched leaf tips Interveinal chlorosis Fe Whiptail disease of leaves Mo

497 Check Point Find out the true statements from the following. (i) Ca2+, Mg 2+ and K+ minimize the toxic effect of heavy elements. (ii) Essentiality of nitrogen was established by Hoagland. (iii) Iron is essential as electron acceptor. (iv) The common symptom of nitrogen deficiency in plants is chlorosis. (v) Sulphur is a constituents of the porphyrin ring of chlorophyll structure. (vi) Copper is responsible for marsh spot disease. (vii) Deficiency symptoms also depends on the mobility of the element in the plant. (viii) Toxic effect may be due to the direct excess of the micronutrient or its interference in the absorption and functioning of the other nutrients. (ix) Mineral salt absorption is dependent on water absorption. (x) Boron and potassium is responsible for Die back of stem/leaves. (xi) Cytochrome pump theory of mineral absorption (active) was proposed by Lundegardh. (xii) Soil not only supplies minerals but also harbours nitrogen fixing bacteria, other microbes.

498

BIOLOGY Connecting Concepts

Three theories have been discussed to explain the passive absorption of ions. 1. Diffusion (Mass flow) : According to this hypothesis, as the flow of water into the plant increases due to transpiration pull, the uptake of ions into the plant also increases. This occurs due to passive absorption of ions by free diffusion into the apparent free space of a tissue. 2. Ion exchange : Both anions and cations have a tendency to get absorbed on the surface of the cell wall. These absorbed ions exchange with the ions present in the soil solution. Ionic exchange occurs through carbonic acid exchange and contact exchange theory. 3. Donnan equilibrium (given by F.G. Donnan, 1927) : Donnan equilibrium is said to be reached when the product of anions and cations in the internal solutions becomes equal to the product of the anions and cations in the external solution.

MECHANISM OF ABSORPTION OF ELEMENTS 

Elements are absorbed from the soil solution in the form of ions. They are chiefly absorbed through the meristematic regions of the roots near the tips. Mineral salt absorption is independent of water absorption.



Uptake of mineral ions, can be divided in two main phases. •

In the first phase, uptake of mineral ions occurs freely between external solution and free space or outer space (intercellular space and cell wall) of cell. It is passive absorption. Briggs and Robertson (1957) demonstrated the passive absorption of ions by root system.

•

In the second phase, ions are taken into the inner space (cytoplasm and vacuole). This entry or exit is active, as it requires metabolic energy. Hence, it is called active absorption.



Movement of ions into the cells is called influx while movement of ions out of cell is called efflux.



Energy used in these mechanisms comes from metabolic activities, especially respiration. Mineral absorption is mainly active process. Hoagland (1944) indicated active ion absorption and their (ions) accumulation against concentration gradient in green algae Nitella and Valonia. Following evidences show the involvement of metabolic energy in the absorption of mineral salts : (i) Higher rate of respiration increases the salt accumulation inside the cell. (ii) Respiratory inhibitors check the process of salt uptake. (iii) By decreasing oxygen content in the medium, the salt absorption is also decreased. Active transport is necessary for living cells because certain substances must be concentrated and others must be excluded. Active uptake of minerals by roots mainly depends on availability of oxygen.



It has now been accepted that the active absorption of mineral salts involves the operation of a carrier compound present in the plasma membrane of the cells (carrier concept). In addition, there are two theories have been suggested in relation to active mineral absorption. These are cytochrome-pump theory (proposed by Lundegardh, 1950, 1954) and protein lecithin carrier concept (proposed by Bennet-Clark, 1956).



The process of mineral absorption is influenced by the following factors : •

Temperature : The rate of absorption of salts and minerals is directly proportional to temperature.

•

The absorption of mineral ions is inhibited when the temperature has reached its maximum limit, perhaps due to denaturation of enzymes.

•

Light : When there is sufficient light, more photosynthesis occurs. As a result more food energy becomes available and salt uptake increases.

•

Oxygen : A deficiency of O2 always causes a correspond decrease in the rate of mineral absorption. It is probably due to unavailability of ATP. The increased oxygen tension helps in increased uptake of salts.

•

pH : It affects the rate of mineral absorption by regulating the availability of ions in the medium. At normal physiological pH monovalent ions are absorbed more rapidly whereas alkaline pH favours the absorption of bivalent and trivalent ions.

•

Interaction with other minerals : The absorption of one type of ions is affected by other type. The absorption of K+ is affected by Ca++, Mg++ and other polyvalent ions. It is probably due to competition for binding sites on the carrier. However, the uptake of K+ and Br becomes possible in presence of Ca++ions. There is mutual competition in the absorption of K,Rb and Cs ions.

MINERAL NUTRITION

499

TRANSLOCATION OF SOLUTES (MINERAL SALTS) 

By radio-isotopes, it has been proved that inorganic substances move up the plant through xylem. These substances move along with water by transpiration pull.



The rate at which inorganic solutes are translocated through xylem corresponds to the rate of translocation of water. After absorption of minerals by roots, ions are able to reach xylem by two pathways apoplast and symplast pathway.

SOIL AS RESERVOIR OF ESSENTIAL ELEMENTS 

Soil provides anchorage, air, water and minerals to the plants growing in it.



Majority of the nutrients that are essential for the growth and development of plants become available to the roots due to weathering and breakdown of rocks. These processes enrich the soil with dissolved ions and inorganic salts. Since they are derived from the rock minerals, their role in plant nutrition is referred to as mineral nutrition.



Soil consists of a wide variety of substances. Soil not only supplies minerals but also harbours nitrogen-fixing bacteria, other microbes.



Since deficiency of essential minerals affect the crop-yield, there is often a need for supplying them through fertilizers.



Both macro-nutrients (N, P, K, S, etc.) and micro-nutrients (Cu, Zn, Fe, Mn, etc.) form components of fertilizers and are applied as per need.

METABOLISM OF NITROGEN 

Nitrogen occurs in environment as oxides, organic amines etc. Nitrogen content in the environment is 78.8 % by volume.



Plant can not absorb nitrogen in molecular form. It is absorbed by plants in nitrate (NO3– ) and ammonium (NH4+) form.

Nitrogen cycle 

Nitrogen is the most critical element. Apart from carbon, hydrogen and oxygen, nitrogen is the most prevalent element in living organisms.



Nitrogen is found in essential compounds like proteins, nucleic acids, growth regulators and many vitamins.



Plants compete with microbes for the limited nitrogen that is available in soil. Thus, nitrogen is a limiting nutrient for both natural and agricultural eco-systems.



Nitrogen exists as two nitrogen atoms joined by a very strong triple covalent bond (N ≡ N).



N2 gas of atmosphere is converted into ammonia by process of nitrogen-fixation.



In nature, lightening and ultraviolet radiation provide enough energy to convert nitrogen to nitrogen oxides (NO, NO2, N2O). Industrial combustions, forest fires, automobile exhausts and power-generating stations are also the sources of atmospheric nitrogen oxides.



A regular supply of nitrogen to the plants is maintained through nitrogen cycle. Nitrogen cycle is regular circulation of nitrogen amongst living organism.



Nitrogen cycle consists of four processes called nitrogen fixation, ammonification, nitrification and denitrification.

Nitrogen Fixation •

Nitrogen fixation is the conversion of inert atmospheric nitrogen or dinitrogen (N2) into utilizable compounds of nitrogen like nitrate, ammonia and amino acids, etc. There are two methods of nitrogen fixation – abiological and biological.

•

Physical or abiological nitrogen fixation occurs in atmosphere in four steps.

Check Point Fill in the blanks (i)

Nitrogen cycle consists of four process ______,_______, ______, and _______.

(ii) Complete the following equations. (a) Protein  R – NH2  ? + NH3. (b) 2NO2 + ?  HNO2 + ?. ? (c) 2HNO2 + O2  2HNO3. ? (d) N ≡ ?  NH3 (iii) The enzyme involved in biological nitrogen fixation is __________. (iv) The conversion of nitrates and nitrites in soil into atmospheric N2 is called ______________.

500

BIOLOGY (i)

Conversion of nitrogen into nitric oxide due to lightening. Lightening

N 2 + O 2  → 2NO (Nitrogen oxide) (ii) Oxidation of nitrogen oxide into nitrogen dioxide 2NO + O 2  → 2NO 2 (Nitrogen dioxide) (iii) Nitrogen dioxide reaches the soil in the form of nitrous and nitric acid when dissolved in rain water. 2NO 2 + H 2 O  → HNO 2 + HNO3 (iv) These reacts with alkali of soil and form nitrates (absorbable form). HNO3 + Ca or K Salts  → Ca or K nitrates __________ • On industrial scale abiological fixation occurs by Habers – Bosch nitrates process at high pressure and temperature. 450°C N 2 + 3N 2  → 2NH3 (Ammonia) 200 atm

•

Conversion of gaseous nitrogen into nitrogenous compound by living organism like bacteria, cyanobacteria is called biological nitrogen fixation.

Ammonification •

The nitrogenous organic compounds in the dead bodies of plants and animals are converted into ammonia or ammonium ions in the soil. This is carried out by ammonifying bacteria. Ammonia is toxic to the plants but ammonium ions can be safely absorbed by the higher plants.

•

Ammonification occurs due to ammonifying bacteria, e.g., Bacillus mycoides, B. yugaris and B. ramosus, etc.

•

Ammonification is a mineralisation process.

•

→ Ammonia Protein (from dead cells)  → Amino acids 

microbial decomposition

microbial decomposition

(NH3) + Organic acid (ROH).

•

Organic acid released in this process are used by micro-organisms for their own metabolism.

•

Some of this ammonia volatilises and re-enters the atmosphere but most of it is converted into nitrate.

•

If ammonia is not absorbed directly by plants then it is converted to nitrate through the process of nitrification.

Nitrification •

The conversion of NH3 in soil into nitrates (–NO3) and nitrites (–NO2) is called nitrification. It is done by nitrifying bacteria, e.g., Nitrosomonas, Nitrosococcus (convert NH3 into nitrites) and Nitrobacter (convert nitrites into nitrates). Nitrosomonas Nitrosococcus Nitrobacter 2HNO 2 + O 2 → 2HNO3

2NH3 + 3O 2  → 2HNO2 + 2H 2 O •

Nitrifying bacteria are chemoautotrophs and are benefitted by utilizing energy released in oxidation, which is used in chemosynthesis. At soil temperature 30°C – 35°C in alkaline soils and with sufficient moisture and aeration the activity of ammonifying and nitrifying bacteria is found to be maximum.

•

The nitrate thus formed is absorbed by plants and is transported to the leaves. In leaves, it is reduced to form ammonia that finally forms the amine group of amino acids.

Denitrification •

The conversion of nitrates and nitrites in soil into atmospheric N2 is called denitrification, which is done by denitrifying bacteria, e.g., Micrococcus denitrificans and Bacillus denitrificans, Pseudomonas & Thiobacillus.

MINERAL NUTRITION

501

•

Denitrification is also called dissimilatory nitrate reduction.

•

Denitrification occurs in four steps – NO3−  → NO −2  → NO  → N 2 ↑ (Molecular form) Nitrates are reduced to nitrites by the enzyme nitrate reductase. The nitrites are reduced to ammonia by nitrite reductase. The ammonia is so formed is enzymatically incorporated in amino acids.

•

Denitrification does not occur to any significant degree in well aerated soils with moderate amount of nitrates and organic matter. It occurs in water logged anaerobic soils with a high organic matter content.

Ammonification

Nitrification

Denitrification

•

Fig 12.3 Nitrogen cycle

Biological Nitrogen Fixation 

The process of fixing atmospheric nitrogen into the usable (inorganic nitrogenous compound) form by living organism is called biological nitrogen fixation.



The enzyme, nitrogenase which is capable of nitrogen reduction is present in prokaryotes. Such microbes are called N2 - fixers. Nitrogenase

N ≡ N  → NH3 The bacteria may be free living (asymbiotic) or symbiotic. (i)

Free living nitrogen fixing bacteria. Azotobacter, Beijernickia (both aerobic) and Bacillus, Klebsiella, Clostridium (anaerobic).

(ii) Free living nitrogen fixing cyanobacteria. Many free living blue-green algae (BGA) or cyanobacteria perform nitrogen fixation, e.g., Anabaena, Nostoc, Calothrix, Lyngbia, Aulosira, Cylindrospermum, Trichodesmium. Cyanobacteria are mainly responsible for maintaining the fertility and productivity of rice fields. For example, Nostoc, Anabaena, Cylindrospermum are active in sugarcane and maize fields. (iii) Symbiotic nitrogen fixing cyanobacteria. Anabaena and Nostoc species are common symbionts in lichens, Anthoceros, Azolla and Cycas roots are other symbionts.

502

BIOLOGY



   

Connecting Concepts

(iv) Symbiotic nitrogen fixing bacteria. Rhizobium is nitrogen fixing bacterial symbiont of papilionaceous roots. Sesbania rostrata has Rhizobium in root nodules and Aerorhizobium in stem nodules. Frankia is symbiont in root nodules of several nonlegume plants like Casuarina (Australian Pine). The most prominent among them is the legume-bacteria relationship. Species of rodshaped Rhizobium has such relationship with the roots of several legumes such as alfalfa, sweet clover, sweet pea, lentils, garden pea, broad bean, clover beans, etc. The most common association on roots is as nodules. These nodules are small outgrowths on the roots. The microbe, Frankia, also produces nitrogen-fixing nodules on the roots of non-leguminous plants (e.g., Alnus). Nodules act as the site for N2 fixation. It contains leghaemoglobin (a pink pigment) and enzyme nitrogenase (Mo-Fe protein). Both Rhizobium and Frankia are free-living in soil, but as symbionts, can fix atmospheric nitrogen.

Nodule Formation 

 Leghaemoglobin : It is an oxygen scavenger and protects the nitrogen fixing enzyme nitrogenase of the  bacteroids. It is located in the bacteroid membrane. Because of this, nodules appears pink in colour and those which do not contain it generally fix less nitrogen. It is a unique protein and is chemically similar to the haemoglobin. The formation of leghaemoglobin and nitrogen fixing capacity appears to be an outcome of the symbiotic interaction. It acts as the oxygen carrier and restricts the entry of oxygen to the bacteria. If it does not do so, the nitrogen fixing enzyme, the nitrogenase, which is extremely sensitive to oxygen will rapidly degraded by the oxygen.

Nodule formation involves a sequence of multiple interactions between Rhizobium and roots of the host plant. Principal stages in the nodule formation are summarised as follows: • Rhizobia multiply and colonise the surroundings of roots and get attached to epidermal and root hair cells. • When root hair of leguminous plants comes in contact with Rhizobium, it curves or deformed by the chemical substance secreted by the bacteria and result in nodule formation. • The Rhizobia enter the root hair by invading root tissue and reproduce in cortex cell. • Simultaneously the division of cortex cell takes place due to which nodules are formed in the root. • The bacteria living in such nodules gets carbohydrate from host cell and also convert the absorbed atmospheric nitrogen into ammonia. •

It is believed that a combination of cytokinin produced by infected bacteria and auxin produced by plant cell stimulate cell division and extension leading to nodule formation.

•

The formation of root nodules and nitrogen fixation occur under the control of plant nod genes and bacterial nod, nif and fix gene cluster. Hook

Soil particles Root hair

Infection thread containing bacteria

Bacteria Bacteria (a)

(b)

(c)

Mature nodule (d)

Fig. 12.4 Development of root nodules in soyabean

(a) Rhizobium Rhi bacteria contact a susceptible root hair, divide near it. (b) Upon successful infection of the root hair cause it to curl. (c) Infected thread carries the bacteria to the inner cortex. The bacteria get modified into rod-shaped bacteroids and cause inner cortical and pericycle cells to divide. Division and growth of cortical and pericycle cells lead to nodule formation. (d) A mature nodule is complete with vascular tissues continuous with those of the root.

MINERAL NUTRITION 

503

Nitrogen fixation requires the components: (a) a strong reducing agent (FAD). (b) ATP



(c) the enzyme system. During this process, the N2 atmospheric(dinitrogen) is reduced by the addition of hydrogen atoms to ammonia. N2 + 8e– + 8H+ + 16 ATP

2NH3 + H2 + 16ADP + 16Pi N2

Substrate ( molecular nitrogen gas)

N

N

N

N

N

H

H

N

N N

H2

H2

N N

H H

N

H

N N

Reduction

Reduction

Binding of

REDUCTION

Enzyme nitrogenase

H

substrate

H

H

Product H

H N

8H2

H H H H H H

N H

N

Ammonia

N N

H

N

Release of product

Nitrogenase

Fig. 12.5 Steps of conversion of atmospheric nitrogen to ammonia by nitrogenase enzyme complex found in nitrogen fixing bacteria.

Check Point

Synthesis of Amino Acids   

Amino acids are the initial product of nitrogen assimilation. Most of plant can assimilates nitrate as well as ammonium ion (NH4+). NH4+ is used to synthesis of amino acid in plants. The two process for synthesis of amino acid are: • Reductive amination - Ammonia reacts with α-Ketoglutaric acid to form glutaric acid glutamate → Glutamate + NADP + • α-Ketoglutarate + NH4 + + NADPH +  dehydrogenase H2O • •



Transamination - It involves transfer of amino group of one amino acid to keto group of keto acid by the transaminase enzyme.

Fill in the blanks 1. Pigment present in the root nodules of legumes is __________ 2. The best known symbiotic nitrogen fixing bacteria is __________ 3. Leghaemoglobin acts as an ____________ and restricts the admission of _____________ to the bacteria. 4. ___________ is a nitrogen fixing 5.

amino acid1 + α- Keto acid2 → α- Keto acid1 + amino acid2

Glutamic acid is the main amino acid from which the transfer of NH2, the amino group takes place and other (17) amino acids are formed through transamination.

Amides 

Amides contain more nitrogen than amino acids and are the structural part of most protein



Amides are double aminated keto acid, e.g. Asparagine and glutamine. They are formed from two amino acids, namely aspartic acid and glutamic acid, respectively, by addition of another amino group to each. The hydroxyl part of the acid is replaced by another NH2– radicle. Since amides contain more nitrogen than the amino acids, they are transported to other parts of the plant via xylem vessels. In addition, along with the transpiration stream the nodules of some plants (e.g., soyabean) export the fixed nitrogen as ureides. These compounds also have a particularly high nitrogen to carbon ratio.

6.

symbiont of papilionaceous roots. The primary amino acid from which other 17 aminoacids are formed through the process of transamination is __________. Different methods of nitrogen fixation occurring in nature are __________ and __________.

504

BIOLOGY

TYPES OF NUTRITION IN PLANTS 

Generally plants are autotrophic in their mode of nutrition, but there are some examples which are heterotrophic in their mode of nutrition. These plants are unable to manufacture their own food due to lack of chlorophyll or some other reasons.



Examples of heterotrophic nutrition are parasites, saprophytes, carnivorous or insectivorous plants, and symbiotic plants.

Parasites 

These obtain either their organic food prepared by other organisms or depend upon other plants only for water and minerals with the help of which they can synthesize their own food.



Parasites can be classified into two categories : total parasites and semiparasites (or partial) parasites.

Total parasites 

These plants never possess chlorophyll. Hence, they always obtain their food from the host. They may be attached to branches, stem (stem parasites) or roots (root parasites) of the host plants. • Total stem parasite: Cuscuta is a rootless, yellow coloured, slender stem with small scale leaves, which twines around the host. The parasite develops haustoria (small adventitious sucking roots) which enter the host plant forming contact with xylem and phloem of the host. It absorbs prepared food, water and minerals from the host plant. • Total root parasite : Total root parasites are common in the families like Orobanchaceae, Rafflesiaceae, Balanophoraceae, etc. Orobanche, Rafflesia and Balanophora are some of the common root parasites.

Semi parasite or partial parasite •

• • •

Such parasitic plants have chlorophyll and, therefore, synthesize their organic food themselves. But they fulfil their mineral and water requirements from their host plants. These are of two types : Partial stem parasites and Partial root parasites. Partial stem parasites : The well known example of partial stem parasite is Viscum album (mistletoe) which parasitizes a number of shrubs and trees. Partial root parasites : The common example of partial (semi-parasite) root parasite is Santalum album (Sandal wood tree) which is an evergreen partial root parasite grows in South India. It grows on the roots of Dalbergia sisso, Eucalyptus. Like other partial parasites, it also has green leaves and absorbs only minerals and water from the host plants.

Saprophyte 

These plants live upon dead organic matter and are responsible for conversion of complex organic substances into simple inorganic substances (minerals), e.g., some bacteria, some fungi (Yeast (Yeast, Mucors, Penicillium, Agaricus), few algae (Polytoma), few bryophytes ((Buxbaumia, Hypnum and Splanchnum), few pteridophytes (like Botrychium) and some angiosperms (Monotropa and Neottia) also.

Carnivorous or Insectivorous Plants 

These plants are autotrophic in their mode of nutrition but they grow in marshy or muddy soils, which are generally deficient in nitrogen and in order to fulfil their nitrogen requirement, these plants catch small insects. The organs and specially leaves of these plants are modified variously to catch the insects.

MINERAL NUTRITION

505



These plants have glands secreting proteolytic enzymes which breakdown complex proteins into simple nitrogenous substances, which inturn are absorbed by these plants.



Some of these plants are as follows:

Tentacles

•

Drosera (Sundew) : It is a herbaceous plant having spathulate or lunate leaves. The leaves are covered by glandular hair with a swollen tip. These long special hair are generally referred to as ‘tentacles’. Similar tentacles are also found in Drosophyllum.

•

Utricularia (Bladderwort) : It is submerged floating aquatic herb which lacks roots. Some of the species of Utricularia also occur in moist soil. The leaves are dissected into fine segments and appear like roots. Some of the leaf segments are modified into (B) pear-shaped sacs called bladders or utricles. Nepenthes (Pitcher plant) : It is an endangered species. In this plant the leaf base is winged, petiole is tendrillar and the lamina is modified into pitcher. Other insectivorous (A) plants having leaf pitchers are Sarracenia, Cephalotus, Heliamphora, etc. Fig. 12.6 Insectivorous plant : Winged Drosera (A) Complete plant, petiole (B) One leaf

•

Lid

Tendrillar petiole

Pitcher Fig. 12.7 Insectivorous plant : Nepenthes (Pitcher plant) A pitcher plant with pitcher

•

Dionea (Venus fly trap) : It is a small herbaceous plant found mainly in America. The plant has a rosette of radiating leaves. The petiole is winged and photosynthetic.

•

Sarracenia (Pitcher plant; Devil’s boot) : This pitcher plant is found in the temperate Winged regions. It has a very reduced stem which bears a rosette of leaves. The leaves are petiole modified into pitchers. It can easily be distinguished from Nepenthes on the basis of its trumpet-shaped sessile pitchers. The pitchers of Sarracenia lack digestive enzymes Fig. 12.8 Insectivorous plant : and here the insects are decomposed by bacteria.

•

Pinguicula (Butterwort) : It is a herbaceous plant having a basal rosette of ovate leaves.

Glands

Flower

Insect catching leaves

Trigger hairs

Digestine glands (A)

(B)

Fig. 12.9 (A) Pinguicula (Butter wort,) (B) Aldovanda : An open leaf

•

Aldrovanda (Water flea trap) : It is also a rootless, submerged aquatic plant (bog plant) recalling the habit of Utricularia.

Leaf lamina

Dionea (Venus fly trap)

506

BIOLOGY

Symbiotic Plant 

Sometimes two different species of organisms spend much or all of their live in close physical association, deriving mutual benefits. Such an association is known as symbiosis and each organism is known as symbiont.



Symbiotic association may be between two higher plants or between a higher plant and a lower plant. Some common examples of symbiosis are lichen and mycorrhiza.



Lichens is a special group of plants, when an alga and fungus live together and are mutually benefitted (alga provides food and fungus provides water, and minerals.



The fungus component of the lichens, called mycobiont, is generally a member of Ascomycetae or occasionally Basidiomycetae. The algal component of the lichen is known as phycobiont and is generally a member of Chlorophyceae (e.g., Trebouxia) or Cyanophyceae (e.g., Nostoc, Gloeocapsa).



Mycorrhiza is a mutually beneficial association between a fungus and the root of higher plant. In such association the fungal mycelium forms a mantle over the root surface and some of the hyphae penetrate between cortical cells and metabolites are transferred in both directions (i.e. from fungus to the root cells vice-versa).

MINERAL NUTRITION

507

EXERCISE - 1 | NCERT BASED QUESTIONS 1.

The major role of minor elements inside living organisms is to act as (1) binder of cell structure (2) co-factors of enzymes (3) building blocks of important amino acids (4) constituent of hormones 2. Which element is required in comparatively least quantity for the growth of plant? (1) Zn (2) N (3) P (4) Ca 3. Which mineral nutrients are called critical element for crops? (1) N, P, K (2) C, H, O (3) N, S, Mg (4) K, Ca, Fe 4. Which one is an essential mineral, not constituent of any enzyme but stimulates the activity of many enzymes? (1) Zn (2) Mn (3) K (4) Mg 5. Which of the following does NPK denote? (1) Nitrogen, Potassium, Kinetin (2) Nitrogen, Protein, Kinetin (3) Nitrogen, Protein, Potassium (4) Nitrogen, Phosphorus, Potassium 6. Which of the following is not caused by deficiency of mineral nutrition? (1) Necrosis (2) Chlorosis (3) Etiolation (4) Shortening of internodes 7. Generally plants absorbed N2 in the form of (1) NO2– (2) NO3– (3) N ≡ N (4) HNO2 8. Minerals absorbed by roots move to the leaf through (1) xylem (2) phloem (3) sieve tubes (4) none of these 9. Passive absorption of minerals depend on (1) temperature (2) temperature and metabolic inhibitor (3) metabolic inhibitor (4) humidity 10. Nitrifying bacteria (1) oxidize ammonia to nitrates. (2) convert free nitrogen to nitrogen compounds. (3) convert proteins into ammonia. (4) reduce nitrates to free nitrogen. 11. All of the following statements concerning the Actinomycetous filamentous soil bacterium Frankia are correct except, the Frankia (1) can induce root nodules on many plant species. (2) cannot fix nitrogen in the free-living state.

12.

13.

14.

15.

(3) like Rhizobium, usually infects its host plant through root hair deformation and stimulates cell proliferation in the host’s cortex. (4) forms specialized vesicles in which the nitrogenase is protected from oxygen by a chemical barrier involving triterpene hopanoids. The function of leghaemoglobin in the root nodules of legumes is (1) inhibition of nitrogenase activity (2) oxygen removal (3) nodule differentiation (4) expression of nif gene Study the following statements. I. It is a component of chlorophyll. II. It helps to maintain ribosome structure. III. It is a activator for Rubisco and Pepco. IV. It activates the enzymes of respiration and photosynthesis. V. It is involved in synthesis of nucleic acids. Which of the following mineral performs the above functions ? (1) Ca+2 (2) Mg+2 (3) Mn+2 (4) Cl – Which of the following is a component of vitamin (thiamine, biotin), Acetyl CoA, cysteine, methionine and ferrerdoxin? (1) Fe (2) S (3) Co (4) K Match the column-I with column-II (1) (2) (3) (4)

Column-I Mg S I Mn

p. q. r. s.

Column-II Found in some amino acids Structural component of chlorophyll Not important for plants Required for photolysis of water

(1) A-q, B-p, C-r, D-s (2) A-p, B-q, C-r, D-s (3) A-p, B-r, C-s, D-q (4) A-q, B-r, C-p, D-s 16. Which of the following statements are correct ? I. Solution culture/Hydroponics contains all essential minerals except one, the usefulness of which is to be determined. II. Na, Si, Co and Selenium are beneficial element required by higher plants. III. Zn is the activator of nitrogenases while Mo is the activator of alcohol dehydrogenase. IV. Zn is needed for auxin synthesis. (1) All of these (2) I, II, III (3) I, II, IV (4) None of these

508

BIOLOGY

17. Match the Column-I containing minerals with the functions given in Column-II. Column-I I. K II. Mo III. P IV. Mn

A. B. C. D. E.

Column-II Stomatal opening Constituent of cell membrane Photolysis of water Free ion Component of nitrogenase and nitrate reductase

I

II

III

IV

(1)

A, D

E

B

C

(2)

A, E

D

C

B

(3)

A ,E

D

B

C

(4)

D

A

C

B, E

Atmospheric N2

18. Micronutrients are needed in very small amounts because (1) most of them are mobile in the plants. (2) they mainly function as cofactors of enzyme. (3) they play minor role in plant health. (4) only meristems need these nutrients. 19. Which one of the following statements can best explain the term critical concentration ? (1) Essential element concentration below which the plant growth is reduced. (2) Micronutrient concentration below which plant growth becomes stunted. (3) Essential element concentration below which plant remains in the vegetative phase. (4) Essential element below which chlorosis occurs. 20. Nitrogen fixation is a process of (1) converting nitrogen in the air to form a usable form by plants. (2) recycling nitrogen from organic matter in the soil. (3) absorbing nitrogen from the soil. (4) conversion of NO3 to N2 . 21. Reaction carried out by N2 metabolising microbes include – (i) 2HN + 3O  → 2NO + 2H + + H O (ii)

3 2NO 2−

2

2 − + O 2  → 2NO3

23. The different steps in a nodule formation are given below. I. A mature nodule establishes a direct vascular connection with the host for exchange of nutrients. II. Root hair curls and the bacteria invade the root hair. III. Rhizobium bacteria contact a susceptile root hair, divide near it IV. The infection thread is produced carrying the bacteria and grows into the cortex of the root. V. The bacteria get modified into rod-shaped bacteroids and cause inner cortical layer and pericycle to divide to form nodule. The correct sequence is (1) I, II, IV, V (2) III, II, IV, V, I (3) III, II, IV, I, V (4) I, III, V, II, IV 24. Refer the figure given below and select the option which gives correct words for all the four blanks A, B, C and D.

2

Which of the following statements about these reactions is incorrect ? (1) Step (i) is carried out by Nitrosomonas or Nitrococcus. (2) Step (ii) is carried out by Nitrobacter. (3) Both steps (i) and (ii) can be called nitrification. (4) Bacteria carrying out these steps are usually photoautotrophs. 22. Which of the following expression describes nitrogen fixation ? (1) N2 + 3H2 → 2NH3 (2) 2NH4+ + 2O2 + 8e– → N2 + 4H2O (3) 2NH3 → N2 + 3H2 (4) 2N2 + glucose → 2 amino acids

Biological Industrial Electrical N2 fixation N2 fixation N2 fixation Denitrification A

NO2 Soil 'N' Pool

NO3 (Uptake)

B

C

Decaying biomass D

A

B

C

D

(1)

K

Ammonification Animal biomass

Plant biomass

(2)

NH3

(3)

CO2

(4)

CHO

Ammonification Plant biomass Denitrification Animal biomass Nitrification Plant biomass

Animal biomass Plant biomass Animal biomass

(Directions Q.25 to Q.27) : In the following questions more than one answer given may be correct. Select the correct answer and mark them according to the codes given below. Code : (1) a, b & c are correct. (2) a & b are correct. (3) b & d are correct. (4) a & c are correct. 25. Passive mineral absorption take place by (a) facilitated diffusion (b) carrier ions (c) donnan equilibrium (d) protein-lecithin 26. The deficiency symptoms of nitrogen in plants are (a) Inhibition of protein synthesis. (b) delaying of flowering. (c) inhibition of chloroplast formation. (d) dormancy of lateral buds.

MINERAL NUTRITION

509

27. Hydroponics (a) is useful in areas having thin; infertile and dry soils. (b) can regulate pH optimum for a particular crop. (c) increases labour cost. (d) increases problem of weeding. 28. The given diagram shows hydroponic/soilless plant production. Plants are grown in a tube or trough placed on a slight incline. The arrows indicate the direction of flow of nutrient solution.

30.

31.

32. Nutrient solution

Pump

Nutrient solution is sent to the elevated end of the tube from the reservoir by ___________ and it flows back to the reservoir due to ________________. (1) pump, pump (2) gravity, Gravity (3) pump, gravity (4) gravity, Pump 29. The diagram shows the development of root nodule in soyabean. II

I

III

33.

34.

Soil particles

35.

Root hair D A

B

C

Identify A, B, C & D. (1) A-Rhizobial bacteria; B-Cortex cell; C-Outer cortex; D-Infection thread (2) A-Rhizobial bacteria; B-Cortex cell; C-Inner cortex and pericycle cells; D-Infection thread

(3) A-Rhizobial bacteria; B-Endodermal cell; C-Inner endodermis; D-Infection thread (4) A-Nitrosomonas bacteria; B-Cortex cell; C-Inner cortex and pericyle cells; D-Infection thread. Which of the following statements about Rhizobium legume nodule formation is not true ? (1) Rhizobium can only fix nitrogen after it becomes a bacteroid within a root cortex cell. (2) Rhizobium induces invagination of root hairs. (3) Within an infection thread, Rhizobium is still extracellular to the plant. (4) The infection thread can fuse with any root cell of an appropriate legume species. A gardner purchases a commercial fertilizer. The label says that it is 10-20-10. This label refers to the (1) percentage of nitrogen, phosphate and potassium. (2) percentage of nitrogen, carbon and oxygen. (3) rate at which nitrogen is released from the fertilizer. (4) ratio of organic to inorganic matter in the fertilizer. Which of the following element is present in chlorophyll molecule ? (1) Iron (2) Copper (3) Manganese (4) Magnesium The plants make glucose from (1) stem and root (2) water and oxygen (3) water and minerals (4) water and carbon dioxide Which of the following element is a constituent of protein ? (1) Sulphur (2) Potassium (3) Lead (4) Phosphorus Which of the following is the correct name of the process leading to the form of fixed nitrogen preferred by most plants ? (1) Nitrogen fixation (2) Nitrification (3) Reduction (4) Nitrate reduction

510

BIOLOGY

EXERCISE - 2 | Window to Competitive Exams 1.

Mycorrhiza is a symbiotic relationship between roots of higher plants and [CBSE'95] (1) virus (2) fungi (3) bacteria (4) blue green algae 2. The association between blue-green algae and fungi occurs in [CBSE'95] (1) lichens (2) symbiosis (3) cannibism (4) mycorrhiza 3. Which one of the following is a micronutrient for plants? [CBSE'96] (1) Calcium (2) Magnesium (3) Manganese (4) Nitrogen 4. Which one of the following is not an essential element for plants ? [CBSE'96] (1) Potassium (2) Iron (3) Iodine (4) Zinc 5. Which of the following is not caused by deficiency of mineral nutrition? [CBSE'97] (1) Necrosis (2) Chlorosis (3) Etiolation (4) Shortening of internodes 6. Fall of immature leaf is due to the deficiency of [AFMC'97] (1) sulphur (2) phosphorus (3) sodium (4) zinc 7. Uptake of mineral ions against concentration gradient is called [AMU'98] (1) active absorption (2) passive absorption (3) negative absorption (4) none of the above 8. Chlorosis is produced in leaves due to deficiency of Fe, Mg, Mn, N or S. Of these essential elements those that are exclusive constituents of the chlorophyll molecule are [AMU'98] (1) Fe and S (2) N and S (3) Mg and S (4) Mg and N 9. Nickel is a component of enzyme [BHU'98] (1) urease (2) amylase (3) nitrogenase (4) nitrate reductase 10. The deficiency symptom of which of the following element is found first in mature leaves? [BHU'98] (1) Nitrogen (2) Calcium (3) Magnesium (4) Iron 11. The plants grown in magnesium-deficient but urea sprayed soil would show [CBSE'2000] (1) deep green foliage (2) early flowering (3) yellowing of leaves (4) loss of pigments in petals 12. Various fungi are known to accumulate considerable quantities of divalent metals. It includes [BHU'2000] (1) Cd (2) Zn (3) Pb (4) All of these

13. Passive absorption of minerals depend on [CBSE'01] (1) temperature (2) temperature and metabolic inhibitor (3) metabolic inhibitor (4) humidity 14. Enzyme involved in nitrogen assimilation is [CBSE PMT'01] (1) nitrogenase (2) nitrate reductase (3) transferase (4) transaminase 15. Which aquatic fern performs nitrogen fixation? [CBSE'01] (1) Azolla (2) Nostoc (3) Salvia (4) Salvinia 16. Insectivorous plants grow in [AMU'01] (1) calcium deficient soil (2) carbon deficient soil (3) magnesium deficient soil (4) nitrogen deficient soil 17. Fertilizers providing N, P, K all essential elements to plants are called [BHU'01] (1) complete fertilizers (2) incomplete fertilizers (3) manure (4) compost 18. The major portion of the dry weight of plants comprises of [CBSE'03] (1) carbon, hydrogen and oxygen (2) nitrogen, phosphorus and potassium (3) calcium, magnesium and sulphur (4) carbon, nitrogen and hydrogen 19. The major role of minor elements inside living organisms is to act as [CBSE'03] (1) binder of cell structure. (2) co-factors of enzymes. (3) building blocks of important amino acids. (4) constituent of hormones. 20. Which one of the following mineral elements plays an important role in biological nitrogen fixation ? [BHU'09,10, AIEEE'04, AFMC'02, DPMT'07, CBSE'03] (1) Molybdenum (2) Copper (3) Manganese (4) Zinc 21. Boron in green plants assists in [CBSE'03] (1) sugar transport (2) activation of enzymes (3) acting as enzyme cofactor (4) photosynthesis 22. Grey spots of oat are caused by deficiency of [CBSE'03] (1) Fe (2) Cu (3) Zn (4) Mn 23. A small aquatic plant was put in each of the petridishes -X, Y & Z, containing different culture solutions. After six weeks the plant in dish X had the same number of leaves as it had previously & were all small and yellowish. Plant

MINERAL NUTRITION

511

in dish Y had more leaves of normal size and dark green colour. Plants in dish Z had more leaves of normal size but very pale. Which of the following show the element missing in the culture? [AMU'03] X Y Z (1) Magnesium Phosphorus Nitrogen (2) Phosphorus Magnesium Nitrogen (3) Phosphorus Nitrogen Magnesium (4) Magnesium Nitrogen Phosphorus 24. Hydroponics is the method of [JK'11, AFMC'03] (1) water conservation. (2) plant development in water without soil. (3) plant development without soil. (4) plant development in saline soil. 25. A free living nitrogen-fixing cyanobacterium which can also form symbiotic association with the water fern Azolla is [CBSE'04] (1) Tolypothrix (2) Chlorella (3) Nostoc (4) Anabaena 26. Which of the following is/are not an essential

micro.nutrient? (1) Boron (2) Nickel and cadmium (3) Molybdenum

(1) (2) (3) (4)

35.

36.

[AMU'04]

(4) Zinc 27. Nitrogen fixing symbiont of Azolla is [AIEEE'04] (1) Azotobacter (2) Anabaena (3) Agrobacterium (4) Chlorella 28. The appearance of yellow edges over leaves is due to the deficiency of the mineral element [KCET'04] (1) Calcium (2) Magnesium (3) Potassium (4) Sulphur 29. Which one of the following is a free living aerobic and nonphotosynthetic nitrogen fixing bacterium ? [J&K'04] (1) Azotobacter (2) Rhizobium (3) Anabaena (4) Clostridium 30. Passive absorption of mineral salts is not dependent upon [J&K'04] (1) diffusion (2) osmosis (3) donnan equlibrium (4) ionic exchange 31. The deficiencies of micronutrients, not only affects growth of plants but also vital functions such as photosynthetic and mitochondrial electron flow. Among the list given below, which group of three elements shall affect most, both photosynthetic and mitochondrial electron transport? [CBSE'05] (1) Co, Ni, Mo (2) Ca, K, Na (3) Mn, Co, Ca (4) Cu, Mn, Fe 32. Which of the following can fix atmospheric nitrogen ? [CBSE'95, HPPMT'05] (1) Albugo (2) Cystopus (3) Saprolegnia (4) Anabaena 33. Which of the following gene clusters in bacteria is responsible for nitrogen fixation? [Kerala'05] (1) nod, nod nif, nif fix (2) nod, nod nif, nif nfx (3) nod, nod nix, nfx (4) ndx, nif, nif fix 34. Match the words of column I with the phrases in column II. Choose the answer which gives the correct combination. [Kerala'05]

37.

38.

39. 40.

41.

42.

43.

44.

45.

Column I Column II Magnesium (p) Found in some amino acids Sulphur (q) Not important for plants Iodine (r) Structural component of chlorophyll Manganese (s) Component of sugar (t) Required for enzyme activity

(1) (1) – (r), (2) – (s), (3) – (q), (4) – (p) (2) (1) – (r), (2) – (p), (3) – (q), (4) – (s) (3) (1) – (r), (2) – (p), (3) – (q), (4) – (t) (4) (1) – (s), (2) – (r), (3) – (p), (4) – (t) The macronutrient which is an essential component of all organic compounds, yet not obtained by plants from soil is [Kerala'05] (1) nitrogen (2) carbon (3) phosphorus (4) magnesium Identify the correct order of the following four zones in the root from apex to base [APMEE'05] (1) Mineral absorption zone (2) Meristematic zone (3) Maturation zone (4) Water absorption zone The correct order is (1) (2), (1), (4), (3) (2) (4), (3), (2), (1) (3) (2), (4), (1), (3) (4) (1), (2), (4), (3) Bacteria which reduce nitrates in soil to nitrogen are [Orissa'05] (1) Nitrosomonas (2) Pseudomonas (3) Rhizobium (4) Clostridium Symbiotic nitrogen fixation in nonleguminous plant is carried out by [Orissa'05] (1) Azotobacter (2) Bradyrhizobium (3) Clostridium (4) Frankia N2 fixation is [Orissa'05] (1) N2 → NH3 (2) N2 → NO3 (3) N2 → Amino acid (4) Both (1) and (2) Insectivorous plants live in a soil that is usually deficient in [Orissa'05] (1) nitrate (2) chloride (3) potassium (4) magnesium Which of the following is a free living nitrogen fixing bacterium? [DPMT'09, HPPMT'05, J&K CMEE'05] (1) Rhizobium (2) Anabaena (3) Pseudomonas (4) Azotobacter Conversion of ammonia into nitrates through Nitrosomonas is called [HPPMT'05, J&K CMEE'05] (1) nitrogen fixation (2) nitrification (3) denitrification (4) ammonification Which of the following pigment is essential for nitrogen fixation by leguminous plants ? [HPPMT'05] (1) Anthocyanin (2) Phycocyanin (3) Phycoerythrin (4) Leghaemoglobin The component of nitrogenase and nitrate reductase is [Orissa'05] (1) N (2) Mo (3) Co (4) no specific component A mineral not essential for plants is [CET Chd'06] (1) sodium (2) potassium (3) zinc (4) iron

512

BIOLOGY

46. Dieback disease occurs in deficiency of [CET Chd'06] (1) potassium (2) copper (3) boron (4) iron 47. Deficiency of which of the following can cause yellowing of intravenous region of leaves ? [Gugarat CET'06] (1) Calcium (2) Potassium (3) Copper (4) Phosphorus 48. If the size of fruits diminishes in plants, which mineral ion should be added to soil ? [Gugarat CET'06] (1) Copper (2) Calcium (3) Boron (4) Chlorine 49. Which of the following contains copper ? [BV'06] (1) Quinone (2) Plastoquinone (3) Plastocyanin (4) None of these 50. Brown heart disease in cauliflower is due to the deficiency of [BV'06] (1) iron (2) copper (3) boron (4) phosphorus 51. The atmospheric nitrogen is fixed in the soil in the form of [BV'06] (1) nitrite (2) nitrate (3) ammonia (4) hydroxylamine 52. Which of the following is not essential macro-element for the growth the plants? [BV'06] (1) N (2) Zn (3) Ca (4) K 53. Sulphur is component of [RPMT'06] (1) protein (2) DNA (3) RNA (4) Both (2) an (3) 54. Match the following and choose the correct combination from the options given. [Kerala'06] a. b. c. d.

55. 56.

57.

58.

59.

Column I Potassium Sulphur Molybdenum Zinc

I II III IV

Column II Constituent of ferredoxin Involved in stomatal movement Needed in the synthesis of auxin Component of nitrogenase

(1) a-II, b-I, c-IV, d-III (2) a-I, b-II, c-III, c-IV (3) a-IV, b-III, c-II, d-I (4) a-I, b-III, c-IV, d-II Premature leaf fall is due to deficiency of [Kerala'06] (1) phosphorus (2) nitrogen (3) calcium (4) potassium Name of elements which occur in nucleic acid marcromolecule ? [Kerala'06] (1) C, H, O, N, S (2) C, O, N, S (3) C, O, P, S (4) C, H, O, N, P A plant requires magnesium for [CBSE'07] (1) protein synthesis (2) chlorophyll synthesis (3) cell wall development (4) holding cells together. Which one of the following elements is not an essential micronutrient for plant growth? [CBSE'07] (1) Zn (2) Cu (3) Ca (4) Mn Which one of these do plants require for the formation of ATP? [AFMC'2000, BHU'2007] (1) N, Ca (2) N, P (3) N, Cu (4) K

60. The process of decay of dead organic matter is known as [BHU'07] (1) denitrification (2) gibberellin (3) nitrogen fixation (4) ammonification 61. Molybdenum causes [BHU'07] (1) mottling (2) reclamation (3) wilting (4) chlorosis 62. An essential element is that which [Karnataka CET'07] (1) is found in plant ash. (2) is available in the soil. (3) improves health of the plant. (4) is irreplaceable and indispensable for growth of plants. 63. Which element is required in the germination of pollen grain? [Gujarat CET'07] (1) Chlorine (2) Potassium (3) Boron (4) Calcium 64. During nitrification, which bacteria converts ammonia to nitrite ? [HPPMT'07] (1) Nitrobacter (2) Pseudomonas (3) Nitrosomonas (4) Mycobacterium 65. An example of phosphate solubilizing symbiotic association is [HPPMT'07] (1) Azolla (2) Rhizobium (3) Pseudomonas (4) Mycorrhiza 66. Element which regulates stomatal movement is [J&K'07] (1) sodium (2) potassium (3) sulphur (4) phosphorus 67. “Mottled chlorosis’’ on the leaves occur due to the deficiency of [J&K'07] (1) nitrogen (2) potassium (3) sulphur (4) phosphorus 68. Enzyme nitrogenase is responsible for [J&K'07] (1) nitrification (2) nitrite reduction (3) nitrate reduction (4) nitrogen fixation 69. The mineral present in cell wall is [MPPMT'07] (1) Na (2) K (3) Ca (4) Mg 70. Nitrifying bacteria are able to [MPPMT'07] (1) convert atmospheric nitrogen into soluble form. (2) convert ammonia to nitrate. (3) convert ammonia to nitrogen. (4) convert nitrate to nitrogen. 71. Zn, Mo, Fe, Cu are [DPMT'07, Punjab PMT'07] (1) trace elements (2) non-essential elements (3) macro-elements (4) None of these 72. Which of the following element is very essential for uptake and utilization of Ca2+ and membrane function? [Kerala CET'07] (1) Phosphorus (2) Molybdenum (3) Manganese (4) Boron 73. N2 + 8e– + 8H+ + 16 ATP → 2NH4 + H2 + 16ADP + 16Pi The above equation refers to [Kerala CET'07] (1) ammonification (2) nitrification (3) nitrogen fixation (4) denitrification 74. Which of the following is not a microelement for plants ? [Orissa'07] (1) Cu (2) B (3) Zn (4) Ca

MINERAL NUTRITION

513

75. Which of the following is a microelement ? [Orissa'07] (1) Potassium (2) Phosphorus (3) Manganese (4) Magnesium 76. The most abundant minerals of a living cell are [Punjab PMT'07] (1) C, H, O, N, Fe (2) C, H, O, N, P (3) C, H, Fe, Mg, Ca (4) C, H, O, K, Na 77 . Nitrite is converted into nitrate by [Punjab PMT'07] (1) Nitrosomonas (2) Nitrobacter (3) Pseudomonas (4) Clostridium 78. Leghaemoglobin helps in [Punjab PMT'07] (1) Nitrogen fixation (2) Protecting nitrogenase from O2 (3) Destroys bacteria (4) Transport of food in plants 79. Essential elements of plants are obtained from [AMU'08] (1) soil (2) soil and water (3) water and atmosphere (4) soil, water and atmosphere 80. The deficiency disease, ‘Dieback of shoots’ of plants is caused by the deficiency of [AMU'08] (1) boron (2) zinc (3) manganese (4) copper 81. Oxides of nitrogen and fluorides are responsible for [AMU'08] (1) reduction in crop yield (2) chlorosis and necrosis of leaf (3) curling and discolouration of petals (4) yellowing and shedding of leaves 82. Nitrification is the process of conversion of [DPMT'08] (1) NH3 (2) NO2 (3) NO3 (4) All of these 83. Which one of the following plant functions as symbiotic nitrogen fixing plant ? [DPMT'08] (1) Cycas (2) Azolla (3) Moss (4) Marchantia 84. Which of the following option shows correct co-relation between Column-I, II and III. [Gujarat CET'08] Calumn-I (1) Calcium

(I)

(2) Boron

(II)

(3) Phosphorus (III) (4) Chlorine

(IV)

(e) Manganese

(V)

(1) (2) (3) (4)

Column-II Required for ionicbalance. Essential for constitution of nucleic acid Required for absorption of calcium. Required to activate respiratory enzyme. Required for synthesis of bipolar spindle.

Column-III (i) Grey blot on leaves. (ii) Fruit-yield decreases.

85. Which of the following is a symbiotic nitroger fixer? [CBSE'09] (1) Azotobacter (2) Frankia (3) Azolla (4) Glomus 86. Appearance of brown spots surrounded by chlorotic veins is a prominent toxicity symptom of [AMU'09] (1) Mn (2) Mo (3) Mg (4) Zn 87. Which of the following is not an essential element? [AFMC'09] (1) Iron (2) Manganese (3) Zinc (4) Iodine. 88. Azotobacter and Beijerinckia are the examples of [BHU'09] (1) symbiotic nitrogen-fixers (2) non-symbiotic nitrogen-fixers (3) ammonifying bacteria (4) disease causing bacteria 89. Which of the following is a nitrogen fixing bacterium ? [BHU'09] (1) Rhizobium leguminosarum (2) Cannabis sativa (3) Linum usitatissimum (4) Mycobacterium leprae 90. The enzyme responsible for the reduction of molecular nitrogen to the level of ammonia in leguminous root nodule is [Kerala'09] (1) nitrogenase (2) nitrite reductase (3) nitrate reductase (4) hydrogenase 91. Study the following lists. [EAM CET'09] (1) (2) (3) (4)

92.

(iii) Red blots on leaves. (iv) Fruit-size diminishes. (v)

Young root tip begin to die.

(a-I-iv), (b-II-v), (c-III-iii), (d-IV-i), IV-i), (e-V-ii) IV (a-V-v), (b-IV-iv), (c-III-i), (d-III-iii), (e-I-ii) (a-IV-iii), (b-I-iv), (c-V-v), (d-III-ii), (e-II-i) (a-V-v), (b-III-iv), (c-II-iii), (d-I-ii), (e-IV-i)

93.

94.

95.

List I Photolysis of water Diazotrophy Cytochrome 'c' oxidase Biosynthesis of IAA

(i) (ii) (iii) (iv) (v)

List II Zinc Copper Manganese Molybdenum Boron

Identify the correct match. (1) a – iii, b – iv, c – ii, d – i (2) a – v, b – ii, c – iii, d – iv (3) a – iii, b – ii, c – i, d – iv (4) a – iv, b – i, c – iii, d – ii Manganese is required in: [CBSE PMT 2009] (1) plant cell wall formation (2) photolysis of water during photosynthesis (3) chlorophyll synthesis (4) nucleic acid synthesis Which one of the following pairs is wrongly matched? [CBSE PMT 2009] (1) Alcohol - nitrogenase (2) Fruit juice - pectinase (3) Textile - amylase (4) Detergents - lipase Which of the following is a symbiotic nitroger fixer? [CBSE PMT 2009] (1) Azotobacter (2) Frankia (3) Azolla (4) Glomus The enzyme responsible for the reduction of molecular nitrogen to the level of ammonia in leguminous root nodule is [Kerala PMT 2009] (1) nitrogenase (2) nitrate reductase (3) nitrite reductase (4) hydrogenase

514 96.

97.

98.

99.

100.

101.

102. 103.

104.

105.

106.

107.

BIOLOGY Which one of tthe following is an amide involved in nitrogen assimilation by plants? [Kerala PMT 2009] (1) Glutamate (2) Alanine (3) Asparagine (4) Serine The minerals involved in the photolysis of water are [Kerala PMT 2009] (1) manganese (2) calcium (3) magnesium (4) chloride (1) A and B only (2) A, B and D only (3) A, B and C only (4) C and D only Which one of the following is not a micronutrient? [CBSE'10] (1) Molybdenum (2) Magnesium (3) Zinc (4) Boron Which of the following is a free living aerobic nonphotosynthetic nitrogen-fixer? [CBSE'97, Orrissa'10] (1) Rhizobium (2) Azotobacter (3) Azospirillum (4) Nostoc Which one of the following is free-living, anaerobic nitrogen - fixer ? [CBSE'10] (1) Beijernickia (2) Rhodospirillum (3) Rhizobium (4) Azotobacter Micronutrients are needed in amounts equivalent to [AMU'10] (1) 8 m mole / kg of dry matter (2) 18 m mole / kg of dry matter (3) 25 m mole / kg of dry matter (4) 30 m mole / kg of dry matter Denitrification is carried out by [AMU'10] (1) Nitrosomonas (2) Pseudomonas (3) Nitrobacter (4) Nitrococcus Plant obtains nitrogen from soil in the form of [AFMC'10] (1) nitrite (2) nitrate (3) ammonia (4) hydroxylamine Manganese is required in [CBSE'09, 10M] (1) plant cell wall formation (2) photolysis of water during photosynthesis (3) chlorophyll synthesis (4) nucleic acid synthesis Leguminous plants are able to fix atmospheric nitrogen through the process of symbiotic nitrogen fixation. Which one of the following statements is not correct during this process of nitrogen fixation ? [CBSE'10] (1) Leghaemoglobin scavanges oxygen and is pinkish in colour. (2) Nitrogenase is insensitive to oxygen. (3) Nodules act as sites for nitrogen fixation. (4) The enzyme nitrogenase catalyses the conversion of atmospheric N2 to NH3. Necrosis or death of tissue particularly leaf tissue, is due to the deficiency of [Kerala'10] (1) N, K, Mg, Fe, Mn, Zn and Mo (2) Ca, Mg, Cu and K (3) N, K, S (4) N, K, Mg and Fe Match the following and choose the correct combination from the options given. [Kerala'10]

Column I (1) (2) (3) (4)

108. 109.

110.

111.

112.

114.

115.

116.

117.

Column II I II III IV

Chlorophyll Nitrogenase Methionine Auxin

(1) a – I, b – II, c – III, d – IV (2) a – III, b – IV, c – I, d – II (3) a – III, b – I, c – II, d – IV (4) a – II, b – IV, c – I, d – III A nitrogen fixing blue-green alga is [Kerala'10] (1) Ulothrix (2) Spirogyra (3) Anabaena (4) Rhizobium An element playing important role in nitrogen fixation is: [CBSE PMT 2010] (1) Molybdenum (2) Copper (3) Manganese (4) Zinc Which one of the following is not a micronutrient? [CBSE PMT 2010] (1) Molybdenum (2) Magnesium (3) Zinc (4) Boron One of the free -living, anaerobic nitrogen - fixer is: [CBSE PMT 2010] (1) Beijernickia (2) Rhodospirillum (3) Rhizobium (4) Azotobacter Match the following and choose the correct combination from the options given. [Kerala PMT 2010] A B C D

113.

Sulphur Zinc Magnesium Molybdenum

Column I Sulphur Zinc Magnesium Molybdenum

1 2 3 4

Column II Chlorophyll Nitrogenase Methionine Auxin

(1) A – 1, B – 2, C – 3, D – 4 (2) A – 3, B – 4, C – 1, D – 2 (3) A – 3, B – 1, C – 2, D – 4 (4) A – 2, B – 4, C – 1, D – 3 Necrosis, or death of tissue particularly leaf tissue, is due to the deficiency of [Kerala PMT 2010] (1) N, K, S (2) N, K, Mg and Fe (3) Mn, Zn and Mo (4) Ca, Mg, Cu and K Which of the following is a bacterium involved in denitrification? [Kerala PMT 2010] (1) Nitrococcus (2) Nitrosomonas (3) Pseudomonas (4) Nitrobacter Which one of the following elements in plants is not remobilised? [AMU'09,10, CBSE'11] (1) Phosphorus (2) Calcium (3) Potassium (4) Sulphur Which one of the following is not an essential mineral element for plants while the remaining three are? [CBSE'11M] (1) Iron (2) Manganese (3) Cadmium (4) Phosphorus A prokaryotic autotrophic nitrogen fixing symboint is found in [CBSE'11] (1) Alnus (2) Cycas (3) Cicer (4) Pisum

MINERAL NUTRITION 118. ‘Whip-tail’ disease in cauliflower is due to deficiency of [AMU'07, AFMC'11] (1) manganese (2) magnesium (3) molybdenum (4) nitrogen 119. An example of micronutrient is [AMU'08, J&K PMT'11] (1) calcium (2) potassium (3) zinc (4) sulphur 120. Function of leghaemoglobin (a red pigment) in root nodules of leguminous plants is to regulate [AMU'11] (1) O2 supply in cells. (2) CO2 supply in cells. (3) production of phenolic compounds. (4) the Mo supply in cells. 121. Which of the following is not an essential element for plants ? [AMU'11] (1) Aluminium (2) Copper (3) Iron (4) Zinc 122. Which of the following is a bacterium involved in denitrification ? [Kerala'10 MP PMT'10 JK PPMT'11] (1) Nitrococcus (2) Azotobacter (3) Pseudomonas (4) Nitromonas 123. Necrosis in crops is due to the deficiency of [DMPT'11] (1) Ca, K, S and Mo (2) N, S, Fe and Zn (3) N, K, S and Mo (4) Mg, S, Mn and Ca 124. In root nodules of legumes, leghaemoglobin is important because it [DMPT'11] (1) transports oxygen to the root nodule. (2) acts as an oxygen scavenger. (3) provides energy to the nitrogen fixing bacterium. (4) acts as a catalyst in transamination. 125. Leghaemoglobin is [DMPT'11] (1) an oxygen carrier in human blood. (2) an oxygen scavenger in root nodules. (3) a proteins used as food supplement. (4) a plants protein with high lysine content. 126. Denitrification is carried by bacteria [HPPMT'11] (1) Pseudomonas and Thiobacillus (2) Nitrosomonas and Nitrococcus (3) Nitrosomonas and Nitrobacter (4) Pseudomonas and Nitrococcus 127. Enzyme nitrogenase contains element [Wardha'11] (1) potassium (2) zinc (3) molybdenum (4) manganese 128. A prokaryotic autotrophic nitrogen fixing symboint is found in : [CBSE PMT 2011] (1) Alnus (2) Cycas (3) Cicer (4) Pisum 129. Which one of the following elements in plants is not remobilised? [CBSE PMT 2011] (1) Phosphorus (2) Calcium (3) Potassium (4) Sulphur 130. Nitrifying bacteria : [CBSE PMT 2011] (1) oxidize ammonia to nitrates (2) convert free nitrogen to nitrogen compounds (3) convert proteins into ammonia (4) reduce nitrates to free nitrogen 131. The function of leghaemoglobin in the root nodules of legumes is : [CBSE PMT 2011] (1) inhibition of nitrogenase activity (2) oxygen removal (3) nodule differentiation (4) expression of nif gene

515 132. Which one of the following is not an essential mineral element for plants while the remaining three are [CBSE PMT 2011M] (1) Iron (2) Manganese (3) Cadmium (4) Phosphorus 133. Which one of the following is essential for photolysis of water ? [CBSE PMT 2011M] (1) Manganese (2) Zinc (3) Copper (4) Boron 134. ‘Whip-tail’ disease in cauliflower is noted due to deficiency of [AFMC 2011] (1) manganese (2) magnesium (3) molybdenum (4) nitrogen 135. A plant require magnesium (Mg) for [JIPMER-2011] (1) holding cells together (2) protein synthesis (3) chlorophyll synthesis (4) cell wall development 136. Which of the following minerals activate the enzymes involved in respiration? [Kerala PMT 2011] (1) Nitrogen and phosphorus (2) Magnesium and manganese (3) Potassium and calcium (4) Sulphur and iron 137. Select the correct match. [Kerala PMT 2011] (1) Nitrosomonas Nitrite to nitrate (2) Thiobacillus Dentrification (3) Nostoc Free-living nitrogen-fixer (4) Azotobacter Anaerobic nitrogen-fixer (1) A and B (2) C and D (3) B and C (4) B and D 138. Which one of the following microbes forms symbiotic association with plants and helps them in their nutrition? [CBSE'12] (1) Azotobacter (2) Aspergillus (3) Glomus (4) Trichoderma 139. A nitrogen-fixing microbe associated with Azolla in rice fields is [AMU'12] (1) Spirulina (2) Anabaena (3) Frankia (4) Tolypothrix 140. Best defined function of Manganese in green plants is : [CBSE'2012] (1) Photolysis of water (2) Calvin cycle (3) Nitrogen fixation (4) Water absorption 141. Which one of the following is correctly matched ? [CBSE'2012] (1) Passive transport of nutrients - ATP (2) Apoplast - Plasmodesmata (3) Potassium - Readily immobilisation (4) Bakane of rice seedlings - F. Skoog 142. Which one of the following is wrong statement? [CBSE'2012] (1) Anabaena and Nostoc are capable of fixing nitrogen in free living state also. (2) Root nodule forming nitrogen fixers live as aerobes under free-living conditions. (3) Phosphorus is a constituent of cell membranes, certain nucleic acids and cell proteins. (4) Nitrosomonas and Nitrobacter are chemoautotrophs.

516 143. For its activity, carboxypeptidase requires [CBSE'2012M] (1) zinc (2) iron (3) niacin (4) copper 144. Read the following four statements (A-D). (1) Both, photophosphorylation and oxidative phosphorylation involve uphill transport of protons across the membrane. (2) In dicot stems, a new cambium originates from cells of pericycle at the time of secondary growth. (3) Stamens in flowers of Gloriosa and Petunia are polyandrous. (4) Symbiotic nitrogen-fixers occur in free-living state also in soil. How many of the above statements are correct? [CBSE'2012M] (1) Two (2) Three (3) Four (4) One 145. For its action, nitrogenase requires [CBSE'2012M] (1) Mn2+ (2) light (3) high input of energy (4) super oxygen radicals 146. Best defined function of Manganese in green plants is : [CBSE PMT 2012] (1) Photolysis of water (2) Calvin cycle (3) Nitrogen fixation (4) Water absorption 147. Which one of the following is correctly matched ? [CBSE PMT 2012] (1) Passive transport of nutrients - ATP (2) Apoplast - Plasmodesmata (3) Potassium - Readily immobilisation (4) Bakane of rice seedlings - F. Skoog 148. Which one of the following is wrong statement? [CBSE PMT 2012] (1) Anabaena and Nostoc are capable of fixing nitrogen in free living state also. (2) Root nodule forming nitrogen fixers live as aerobes under free-living conditions. (3) Phosphorus is a constituent of cell membranes, certain nucleic acids and cell proteins. (4) Nitrosomonas and Nitrobacter are chemoautotrophs. 149. For its activity, carboxypeptidase requires [CBSE PMT 2012M] (1) zinc (2) iron (3) niacin (4) copper 150. Read the following four statements (A-D). (1) Both, photophosphorylation and oxidative phosphorylation involve uphill transport of protons across the membrane. (2) In dicot stems, a new cambium originates from cells of pericycle at the time of secondary growth. (3) Stamens in flowers of Gloriosa and Petunia are polyandrous. (4) Symbiotic nitrogen-fixers occur in free-living state also in soil. How many of the above statements are correct? [CBSE PMT 2012M] (1) Two (2) Three (3) Four (4) One

BIOLOGY 151. For its action, nitrogenase requires [CBSE PMT 2012M] (1) Mn2+ (2) light (3) high input of energy (4) super oxygen radicals 152. Excessive loss of water causes wilting of leaves, it can be prevented by : [AIIMS 2012] (1) Keeping the plant in bright light (2) Spraying the plant with alcohol (3) Applying vaseline on the leaf surface (4) Adding high amounts of fertilizers to the soil 153. Which one of the following elements is not an essential micronutrient for plant growth? [AIIMS 2012] (1) Ca (2) Mn (3) Zn (4) Cu 154. Which element plays an important role in nitrogen fixation? [AIIMS 2012] (1) Mn (2) Mo (3) Zn (4) Cu 155. Which of the following is not an essential element? [AFMC 2012] (1) Iron (2) Manganese (3) Zinc (4) Iodine. 156. Which of the following is not caused by deficiency of mineral? [JIPMER-2012] (1) Chlorosis (2) Etiolation (3) Shortening of internodes (4) Necrosis 157. What will happen when we inoculate Rhizobium in wheat field? [JIPMER-2012] (1) No increase in production (nitrogen content of soil remains same) (2) A lot of increase in production (nitrogen content of soil increases) (3) Fertility of soil decreases (4) Fertility of soil increases 158. Nitrifying bacteria are able to [JIPMER-2012] (1) convert atmospheric nitrogen into soluble forms (2) convert ammonia to nitrate (3) ammonia to nitrogen (4) nitrate to nitrogen 159. The mineral activates the enzyme catalase and the other is a constituent of the ring structure of chlorophyll. These minerals are respectively [Kerala PMT 2012] (1) iron and magnesium (2) iron and manganese (3) magnesium and manganese (4) calcium and magnesium 160. Find out the correctly matched pair. [Kerala PMT 2012] Nutrients Functions (1) Zinc - Helps to maintain the ribosome structure (2) Magnesium - Needed during the formation of mitotic spindle (3) Calcium - Plays a role in the opening and closing of stomata. (4) Manganese - Needed in the splitting of water to liberate oxygen during photosynthesis

MINERAL NUTRITION 161. The first stable product of fixation of atmospheric nitrogen in leguminous plants is : [AIPMT (NEET) 2013] (1) Ammonia (2) NO3– (3) Glutamate (4) NO2– 162. Which two distinct microbial processes are responsible for the release of fixed nitrogen as dinitrogen gas (N2) to the atmosphere? [NEET Kar. 2013] (1) Anaerobic ammonium oxidation, and denitrification (2) Aerobic nitrate oxidation, and nitrite reduction (3) Decomposition of organic nitrogen, and conversion of dinitrogen to ammonium compounds (4) Enteric fermentation in cattle, and nitrogen fixation by Rhizobium in root nodules of legumes 163. Which of the following elements is a constituent of biotin? [NEET Kar. 2013] (1) Sulphur (2) Magnesium (3) Calcium (4) Phosphorus 164. Match column-I and Column-II and choose the correct option given below the columns. [AIIMS 2013] Column-I Column-II (Element) (Function) A. Calcium 1. Required for ionicbalance. B. Boron 2. Essential for constitution of nucleic acid C. Phosphorus 3. Required for absorption of calcium. D. Chlorine 4. Required to activate respiratory enzyme. E. Manganese 5. Required for synthesis of mitotic spindle. (1) A → 1; B → 2; C → 3; D → 4; E → 5 (2) A → 5; B → 4; C → 3; D → 2; E → 1 (3) A → 4; B → 1; C → 5; D → 3; E → 2 (4) A → 5; B → 3; C → 2; D → 1; E → 4 165. Consider the following statements, [Kerala PMT 2013] (i) Sulphur is present in two amino acids-cysteine and valine. (ii) Low level of N, K, S and Mo causes an inhibition of cell division. (iii) The microbe that produces nitrogen fixing nodules on the roots of non-leguminous plant “Alnus” is Frankia. (iv) Denitrification is carried by the bacteria Nitrosomonas and Nitrobacter. Of the above statements (1) (i) and (ii) alone are correct (2) (i) and (iii) alone are correct (3) (ii) and (iii) alone are correct (4) (ii) and (iv) alone are correct

517 166. The mineral involved in carbohydrate translocation, the mineral required for maintaining ribosome structure and the one required for the activation of the enzyme nitrogenase are respectively [Kerala PMT 2013] (1) Manganese, Boron and Calcium (2) Calcium, Magnesium and Molybdenum (3) Boron, Manganese, and Molybdenum (4) Boron, Magnesium and Molybdenum 167. Deficiency symptoms of nitrogen and potassium are visible first in: [AIPMT 2014] (1) Senescent leaves (2) Young leaves (3) Roots (4) Buds 168. Minerals known to be required in large amounts for plant growth include : [AIPMT 2015] (1) calcium, magnesium, manganese, copper (2) potassium, phosphorus, selenium, boron (3) magnesium, sulphur, iron, zinc (4) phosphorus, potassium, sulphur, calcium 169. Which one gives the most valid and recent explanation for stomatal movements ? [AIPMT 2015] (1) Potassium influx and efflux (2) Starch hydrolysis (3) Guard cell photosynthesis (4) Transpiration 170. ‘Die back’ disease is caused by the deficiency of : [AMU’s 2015] (1) Zinc (2) Copper (3) Manganese (4) Boron 171. The enzyme nitrogenase is a: [AMU’s 2015] (1) Cu - Fe protein (2) Ni - Fe protein (3) Mo - Fe protein (4) Ni - Cu protein 172. The element related with nitrogen metabolism is: [AMU’s 2015] (1) Manganese (2) Megnesium (3) Zinc (4) Molybdenum 173. Which of the following enzymes is associated with the conversion of nitrite into nitrous in the cytosol. [UP CPMT 2015] (1) Nitrate reductase (2) Nitrite reductase (3) Glutamine synthase (4) Glutamine 174. Which one of the following mineral elements plays in important role in photosynthetic oxygen evolution? [UP CPMT 2015] (1) Manganese (2) Magnesium (3) Molybdenum (4) Boron

518

BIOLOGY

EXERCISE - 3 | Test Yourself 1.

In plant nutrition elements are classified as major or minor depending on (1) their availability in the soil. (2) their relative production in the ash obtained after burning the plants. (3) the relative amounts required by the plants. (4) their relative importance in plant growth. 2. Aeroponic is also called as (1) soilless cultivation of plants (2) parthenocarpy (3) vivipary (4) phytotron 3. In plants a common symptom caused by deficiency of P, K, Ca and Mg is the (1) bending of leaf tip. (2) formation of anthocyanin. (3) poor development of vasculature. (4) appearance of dead necrotic areas. 4. Yellowing of tea leaf takes place by the deficiency of (1) chlorine (2) potassium (3) oxygen (4) sulphur 5. Essential macroelements are (1) absorbed from soil. (2) manufactured during photosynthesis. (3) produced by enzymes. (4) produced by growth hormones. 6. Which of the following is not macro-nutrient ? (1) C (2) P (3) S (4) Zn 7. Rapid deterioration of root and shoot tip occurs due to the deficiency of (1) calcium (2) phosphorus (3) nitrogen (4) carbon 8. Micro-nutrients are (1) less important in nutrition than macro-nutrients. (2) as important in nutrition as macro-nutrients. (3) may be omitted from culture media without any detrimental effect on the plant. (4) called micro because they play only minor role in nutrition. 9. Which of the following mineral assists in sugar transport in plants ? (1) B (2) Ca (3) Za (4) K 10. Active uptake of minerals by roots mainly depends on the (1) availability of oxygen (2) light (3) temperature (4) availability of carbon dioxide 11. The plant ash is an indication of. (1) organic matter of plant. (2) waste product. (3) mineral salts absorbed by plants. (4) None of the above

12. Nif genes occur in (1) Rhizobium (2) Aspergillus (3) Penicillium (4) Streptococcus 13. Chlorosis, etiolation and albinism are caused by the deficiency of (1) iron, light and certain genes. (2) zinc, iron and magnesium. (3) magnesium, iron, zinc, light and certain genes. (4) magnesium, zinc and light. 14. Which of the following statement is incorrect ? (1) Plants take very little amount of mineral elements from soil. (2) Plants absorb one thing at a time either water or mineral salt. (3) Root hair absorb water and minerals together. (4) Mineral absorption primarily takes place by active method. 15. Which one of the following is not a free living nitrogen fixing bacteria ? (1) Bacillus polymyxa (2) E.coli (3) Rhodospeudomonas (4) Anabaena 16. Which of the following statements are correct ? (1) Every mineral element that is present in a cell is needed by the cell. (2) Although the functions of essential elements are diverse, they can be grouped into 5 general categories. (3) Nitrogen as a nutrient element is highly immobile in the plants. (4) Deficiencies of essential elements disrupt plant growth and development. 17. The conversion of ammonia to ammonium ion occurs (1) on the ribosomes of cyanobacteria. (2) spontaneously when ammonia is in water. (3) on the dry surfaces of soil particles. (4) on the endoplasmic reticulum of green algae. 18. The given diagram shows a typical setup for hydroponic technique. Select the option which gives correct labelling for A, B and C.

Cotton

B

A

C

MINERAL NUTRITION A (1) Funnel for adding water and nutrients (2) Funnel for adding water only (3) Funnel for adding nutrients only (4) Funnel for adding water and nutrients

519 B

C

Aerating tube Aerating tube Aerating tube Aerating tube

Nutrient solution Nutrient solution Water Water

19. The most important use of potassium is that it (1) provides red colour to fruit. (2) aids photosynthesis. (3) influences enzymatic activity, which regulates many plant processes. (4) helps in the formation of the cambium. 20. Which element is required for the activity of nitrate reductase ? (1) Mo (2) Zn (3) Fe (3) Cu 21. Under anaerobic conditions, denitrifying bacteria such as Pseudomonas could convert (1) nitrates to ammonia (2) nitrite to nitrates (3) nitrates to nitrites (4) nitrates to molecular nitrogen 22. The translocation of food materials in plants takes place by (1) epidermis (2) phloem (3) xylem (4) pith 23. Who proved for the first time that the plants contain a large number of minerals and micro-elements ? (1) De Saussure (1804) (2) Leibeg (1840) (3) Glauber and Mayton (1650) (4) Arnon and Stout (1929) 24. Minerals are known to enter the plant root by means of a number of mechanisms, including all except one of the following. Which one of the following is NOT a mechanism for moving minerals into roots? (1) Foliar feeding (2) Active transport + (3) Proton (H ) pump (4) Cation exchange 25. If a plant is deficient in __________, it will not be able to make DNA. (1) Phosphorus (P) (2) Manganese (Mn) (3) Iron (Fe) (4) Sulphur (S) 26. The most abundant gas in our atmosphere cannot be utilized by plants directly in its atmospheric form and is, therefore, captured by certain bacteria that live symbiotically in the nodules of roots. What is this gas? (1) Oxygen (2) Nitrogen (3) Neon (4) Hydrogen

27. Soil can easily become deficient in_________ because these ions are negatively charged and do not stick to negatively charged clay particles. (1) Nitrate (2) Calcium (3) Ammonium (4) Magnesium 28. Legume's roots have swellings called nodules that (1) produce antibiotics that protect the plant from soil bacteria. (2) provide a steady supply of sugar to the host plant. (3) increases the surface area for water uptake. (4) contain nitrogen-fixing bacteria. 29. White bud condition in maize is produced due to the deficiency of (1) zinc (2) boron (3) molybdenum (4) iron 30. In plants a common symptom caused by deficiencies of P, K, Ca and Mg is the (1) formation of anthocyanin. (2) bending of leaf tip. (3) poor development of vasculature. (4) appearance of dead necrotic areas. 31. Carnivorous plants are often found in acidic and nutrientpoor environments. The main selective pressure for carnivory is (1) lack of nitrogen and phosphorus sources. (2) lack of iron and calcium sources. (3) incomplete ion exchange. (4) all of the above. 32. Enzyme catalyzed reactions can be inhibited by (1) Zn2+ (2) Mg2+ 2+ (3) Hg (4) Cu2+ 33. An example of parasitic plant that is also strictly epiphytic is (1) Cuscuta (2) Viscum (3) Orobanche (4) Drosera 34. Which of the following element is necessary for translocation of sugars in plants ? (1) Boron (2) Molybdenum (3) Manganese (4) Iron 35. Which of the following statements about the cycling of nutrients is not true ? (1) Nitrogen is fixed into organic form by bacteria. (2) Some chemosynthetic autotrophs use H2S to synthesize organic compounds. (3) Heterotrophs must obtain their organic compounds directly from autotrophs. (4) Carbon, hydrogen and oxygen first become part of living material via an autotroph. 36. Which pigment is essential for nitrogen fixation by leguminous plants ? (1) Phycocyanin (2) Leghaemoglobin (3) Phycoerythrin (4) Myoglobin 37. The example of a saprophyte is (1) Nepenthes (2) Utricularia (3) Santalum (4) Monotropa

520 38. A boy notice that the young leaves of his tomato plants are very yellow. What type of deficiency does this suggest ? (1) Nitrogen (2) Carbon (3) Water (4) Iron 39. The dodder (Cuscuta) is a (1) total stem parasite (2) total root parasite (3) partial root parasite (4) partial stem parasite 40. Which of the following groups contain no species that are able to fix nitrogen ? (1) Cyanobacteria in the ocean and fresh water. (2) Soil bacteria including Rhizobium. (3) Cyanobacteria in lichens. (4) Aerobic bacteria in the genera Bacillus and Pseudomonas. 41. Which of the following is an example of insectivorous plants ? (1) Cuscuta C (2) Nepenthes N (3) Rafflesia (4) Orobanche 42. Which of the following statements about nitrification is not true ? (1) Nitrobacter oxidizes nitrite to nitrate. (2) Nitrosomonas and Nitrosococcus convert ammonium ions to nitrite. (3) Nitrification reactions are energy-producing (exergonic) reactions. (4) Heterotrophic plants are more directly dependent on the nitrifying bacteria for usable nitrogen than autotrophic plants. 43. A trace element essential for plant growth and radioisotope, which is used in cancer therapy is (1) cobalt (2) calcium (3) sodium (4) iron 44. Which of the following characteristics defines an element as essential for a particular species? (1) It has to be added as fertilizer to achieve maximum seed production. (2) If it is missing, a plant cannot grow or reproduce normally. (3) If it is present in high concentration, plant growth increases. (4) If it is absent, other nutrients may be substituted for it. 45. Where does most nutrient uptake occur in roots ? (1) At the root tip, where root tissue first encounters soil away from the zone of nutrient depletion. (2) At the Casparian strip, where ions must enter the symplast prior to entering xylem cells. (3) In the symplastic and apoplastic pathways. (4) In root hairs, in the zone of maturation. 46. Ion exchange is an important process that facilitates the uptake of nutrients by plants. Which of the following statements about ion exchange is false ? (1) Ion exchange is most important in soils with high clay content. (2) Clay particles have a permanent negative charge.

BIOLOGY (3) Mineral cations bind more strongly to clay particles than do protons. (4) Negative ions such as phosphate, nitrate, and sulfate are leached from the soil 47. Plant need nutrients from their environment. Which of the following is a nonmineral nutrient obtained from the soil ? (1) Carbon (2) Oxygen (3) Nitrogen (4) Phosphorus 48. Which of the following statements about nitrogen fixation is false ? (1) Nitrogenase is only catalytic under anaerobic conditions. (2) The energy for nitrogen fixation can be provided by either photosynthesis or respiration. (3) In nitrogen fixation, nitrogen is reduced by the addition of three successive pairs of hydrogen atoms. (4) Most nitrogen fixing microbes are aerobic. 49. Which of the following is not a correct pairing of a macronutrient and the major functions it performs in the life of a plant ? (1) Potassium-enzyme activation, water balance, ion balance. (2) Calcium-activity of membranes and cytoskeleton, second messenger. (3) Sulphur-in proteins and coenzymes. (4) Iron-in active sites of many redox enzymes and electron carriers. 50. The mode of catching insects in Drosera plants is by means of (1) sensitive glandular hairs which secrete a sweet, viscous, shining substance. (2) specially sensitive trigger hairs. (3) leaves which are modified into pitcher. (4) leaf segments modified into bladder. 51. Pitcher is a modification of (1) leaf blade (2) leaf apex (3) petiole (4) none of these 52. Which one is a semiparasitic angiospermic plant? (1) Cuscuta

(2) Moss capsule

(3) Cassytha

(4) Penicillium

53. Venus fly trap is provided with (1) glandular hairs (2) sensitive trigger hairs (3) segmented leaf (4) none of the above

MINERAL NUTRITION

521

ANSWER KEY EXERCISE 1 : NCERT BASED QUESTIONS 1. 6. 11. 16. 21. 26. 31.

(2) (3) (2) (3) (4) (3) (1)

2. 7. 12. 17. 22. 27. 32.

(1) (2) (2) (1) (1) (2) (4)

3. 8. 13. 18. 23. 28. 33.

(1) (1) (2) (2) (2) (3) (4)

4. 9. 14. 19. 24. 29. 34.

(3) (1) (2) (1) (2) (2) (1)

5. 10. 15. 20. 25. 30. 35.

(4) (1) (1) (1) (4) (4) (2)

151. (3) 156. (2) 161. (1) 166. (4) 171. (3)

(2) (4) (3) (4) (1) (2) (4) (1) (4) (2) (2) (4) (4) (2) (1) (2) (4) (1) (1) (3) (1) (2) (2) (3) (1) (1) (2) (2) (3) (1)

2. 7. 12. 17. 22. 27. 32. 37. 42. 47. 52. 57. 62. 67. 72. 77. 82. 87. 92. 97. 102. 107. 112. 117. 122. 127. 132. 137. 142. 147.

(1) (1) (4) (1) (4) (2) (4) (2) (2) (2) (2) (2) (4) (2) (4) (2) (4) (4) (2) (2) (2) (2) (2) (2) (3) (3) (3) (3) (3) (3)

3. 8. 13. 18. 23. 28. 33. 38. 43. 48. 53. 58. 63. 68. 73. 78. 83. 88. 93. 98. 103. 108. 113. 118. 123. 128. 133. 138. 143. 148.

(3) (4) (1) (1) (1) (3) (1) (4) (4) (3) (1) (3) (3) (4) (3) (2) (2) (2) (1) (1) (2) (3) (4) (3) (2) (2) (1) (3) (1) (3)

4. 9. 14. 19. 24. 29. 34. 39. 44. 49. 54. 59. 64. 69. 74. 79. 84. 89. 94. 99. 104. 109. 114. 119. 124. 129. 134. 139. 144. 149.

(3) (1) (1) (2) (2) (1) (3) (4) (2) (3) (1) (2) (3) (3) (4) (4) (4) (1) (2) (2) (2) (1) (3) (3) (2) (2) (3) (2) (3) (1)

5. 10. 15. 20. 25. 30. 35. 40. 45. 50. 55. 60. 65. 70. 75. 80. 85. 90. 95. 100. 105. 110. 115. 120. 125. 130. 135. 140. 145. 150.

(3) (1) (1) (1) (4) (2) (2) (1) (1) (3) (1) (4) (4) (2) (3) (4) (2) (1) (1) (2) (2) (2) (2) (1) (2) (1) (3) (1) (3) (3)

(3) (1) (1) (1) (4)

153. 158. 163. 168. 173.

(1) (2) (1) (4) (1)

154. 159. 164. 169. 174.

(2) (1) (1) (1) (1)

155. 160. 165. 170.

(4) (4) (3) (4)

EXERCISE 3 : TEST YOURSELF 1.

(3)

2.

(1)

3.

(4)

4.

(4)

5. 6. 7.

(1) (4) (1)

8.

(2)

9.

(1)

10. 11.

(1) (3)

12.

(1)

13.

(3)

EXERCISE 2 : WINDOW TO COMPETITIVE EXAMS 1. 6. 11. 16. 21. 26. 31. 36. 41. 46. 51. 56. 61. 66. 71. 76. 81. 86. 91. 96. 101. 106. 111. 116. 121. 126. 131. 136. 141. 146.

152. 157. 162. 167. 172.

Major elements are required by plants in quantity of more than 1 milligram/gram dry matter and minor elements are required in quantity of less than 1 milligram/gram of dry matter. Aeroponic plants are grown with their roots bathed in nutrient mist. This method has been successfully used in growing Citrus and olive plants. Necrosis caused by deficiency of minerals appears at specific regions of leaves like tips, margins, interveinal, etc. It usually occurs after chlorosis, e.g., K, P, Ca, Mg, Mn, Cl. Reduced meristematic activity and chlorotic leaves produce tea yellow disease of tea plants. Zn is microelement. Meristematic regions found is stem, leaf and root tips are greatly affected by the absence of calcium because it is not rapidly translocated to these regions. Ultimately they die and thus stop the growth of these organs. Micro-nutrients are present in less amount in plants but they are as important as macro-nutrients. Boron is absorbed by the plants as borate, it is involved in the transport of carbohydrates (sugar). The ash that is left after burning any dry part of the plant, contains only mineral elements and is called plant ash. Nif gene is present in Rhizobium. It is responsible for the synthesis of enzyme nitrogenase which can fix atmospheric nitrogen. Rhizobium leguminosarum bacteria is found symbiotically associated in the root nodules of leguminous plant. 14. (2) 15. (4) 16. (4) 17. (2)

522

BIOLOGY

18. 23.

(1) (2)

24.

(1)

25.

(1)

26.

(2)

27.

(1)

28.

(4)

29.

(1)

30.

(4)

31.

(1)

32.

(4)

33.

(2)

19. (3) 20. (1) 21. (4) 22. (2) Leibeg (1840), is known as the father of biochemistry. He was the first to record mineral/ elements in the plant ash. Potassium is accumulated by passive transport. Some solutes are pumped across membranes using active transport. The role of proton pumps in the transport process of plant cells is a specific application of chemiosmosis, a transmembrane proton gradient that links energy-releasing processes to energy-consuming ones like active transport. Phosphorus is an important component of nucleic acids. Despite the fact that the atmosphere consists 80% nitrogen gas, plants cannot use the element in that form and frequently suffer from nitrogen deficiency. NO3–, is negatively charged and not tightly bound to soil particles. Legume roots have swellings called nodules that contain nitrogen-fixing bacteria of the genus Rhizobium. Due to acute deficiency of zinc, leaves are completely chlorotic called as white bud. In plants a common symptom caused by deficienies of P, K, Ca and Mg is the appearance of dead necrotic areas on the leaves and petioles. Carnivory supplements has insufficient nitrogen and phosphorus availability. Elements like Cu, Fe, Mn, Mo etc., act as cofactors of different enzymes, hence enzyme catalyzed reactions can be inhibited by Cu2+ deficiency. 34.

(1)

35.

(3)

Some heterotrophs, like the carnivores, can obtain organic compounds by consuming other heterotrophs.

36.

(2)

Leghaemoglobin is an oxygen scavenger. The enzyme that catalyses the fixation of nitrogen functions under anaerobic conditions. Leghaemoglobin combines with oxygen and protects Nitrogenase.

37.

(4)

Monotropa is commonly known as Indian pipe. it grows on humus rich soil of pine forests. The aerial part of the plant is not green and bears a few scale leaves at the base of shoot. The underground part of the plant is associated with endotropic mycorrhiza.

38.

(4)

An iron deficiency is suspected in a plant. If the older leaves are yellow, a nitrogen deficiency would be suspected because nitrogen is easily relocated in the plant while iron is not.

39. 42.

(1) (4)

40. (4) 41. (2) Heterotrophic plants are less dependent on nitrogen obtained from nitrification since they receive some nitrite and nitrate through their parasitic or carnivorous nutritional modes.

43.

(1)

44. 49.

(2) (4)

Cobalt stimulates growth of legumes such as beans, clover and alfalfa. This stimulation of growth by cobalt is due to its use, not by the plant itself, but by nitrogen-fixing bacteria that live in roots of plants. 45. (4) 46. (3) 47. (3) 48. (4) 50. (1) 51. (1) 52. (3) 53. (2)

13

Chapter

Photosynthesis At a Glance

While going through the chapter pay special attention to the following – Terms & defination – 1. Quantasome 2. Photosystem 3. Action & Absorption spectrum 4. Quantum yield Differences – 1. Chlorophyll ‘a’ & ‘b’ 2. Light reaction & dark reaction 3. Photosystem I & II 4. Cyclic & Non-cyclic photophosphorylation 5. C3 & C4 Plants Flowchart – 1. Mechanism of Photosynthesis. 





Early Experiments Site of photosynthesis Photosynthetic Pigments

  





•

It is also responsible for the release of oxygen into the atmosphere by green plants.

The process of photosynthesis can also be defined as the transformation of photonic energy (i.e. light or radiant energy) into chemical energy (locked in high energy bonds of carbohydrate molecules) by the green parts of the plants.



The simplest equation for photosynthesis in higher plants and algae is given belowLight Chlorophyll

6CO 2 + 12H 2O    → C6 H12O6 + 6O 2 ↑ +6H 2O Photosynthesis is an anabolic or constructive process.

Absorption & Action spectra Light Reaction 

Transfer of energy



Drop





System





Electron Transport

Photolysis of water

Photophosphorylation Chemiosmotic

hypothesis

Dark Reaction  

 

Emerson’s Effect & Red Two pigment system



Photosynthesis is important due to two reasons: It is the primary source of all food on earth.

Carotenoids



Green plants capture energy from sun and convert it into chemical energy (food) with the help of CO2 taken from atmosphere, water from soil and releases oxygen. This food is consumed by other animals. So they are called as heterotrophs. Thus, photosynthesis is the single most important biological process required for human existence. During photosynthesis photoautotrophs utilize only 0.2% of the solar energy, incident on the earth surface. •

Chlorophyll

Mechanism of Photosynthesis

Photosynthesis is the process by which plants and other organisms, such as algae and some bacteria synthesize their own food in presence of light. So, they are called as autotrophs.





  

Calvin Cycle C4 Cycle

 CAM Photorespiration Factors affecting photosynthesis

524

BIOLOGY

Experimental proves regarding requirements of photosynthesis

Some experiments proves that some factors are essential for photosynthesis like chlorophyll, light, CO2 etc. Chlorophyll : Take a fresh variegated leaf of Coleus C or Croton C plants growing in bright sunlight. Trace the outline of the leaf and its non green parts on a tracing paper. Boil the leaf in 70% alcohol till it decolorize. Take out the leaf and wash it with water. Immerse the leaf in iodine solution. The green chlorophyll containing parts of the leaf turn blue, while the non green parts remain pale. This shows that chlorophyll is essential for photosynthesis.

Fig. 13.1 Experiment to demonstrate that chlorophyll is essential for photosynthesis.

Light : Take two leaves es – a variegated leaf or a leaf that was partially covered with black

paper, and one that was exposed to light. On testing these leaves for starch it was clear that photosynthesis occurred only in the green parts of the leaves in the presence of light.

Fig. 13.2 Experiment to demonstrate that light is essential for photosynthesis. CO2 : (Moll’s half leaf experiment) Take a leaf, in which a part of a leaf is enclosed in a test tube containing some KOH solution (which absorbs CO2), while the other half is exposed to air. The setup is then placed in light for some time. On testing for starch later in the two halves of the leaf, it was found that the exposed part of the leaf showed positive result for starch while the portion that was in the tube, tested negative. This concluded that CO2 was required for photosynthesis.

Connecting Concepts Fill in the blanks. 1. Moll’s half leaf experiment shows that ______ is essential for photosynthesis. 2. ________plotted the action spectrum of photosynthesis. 3. John Priestley termed the impure air as________ and the pure air as ________. 4. Purple and green sulphur bacteria use ________as the hydrogen donar. 5. __________ showed that the process of photosynthesis takes place in chloroplast and results in the synthesis of starch.

Split cork Wide mouth bottle KOH solution

Bluish part c Potted plant (destarched)

b a

Colourless parts (A)half leaf experiment Fig. 13.3 Moll’s

(B)

PHOTOSYNTHESIS

525

EARLY EXPERIMENTS / HISTORY OF PHOTOSYNTHESIS 

It is important to know about simple experiments that led to a gradual development in the understanding of the process of photosynthesis.



Joseph Priestley (1733-1804)









•

He performed a series of experiments (1770), that revealed the essential role of air in the growth of plants.

•

He observed that a candle burning in a closed space gets extinguished soon. Similarly, a mouse would suffocate soon in a closed space.

•

He concluded that a burning candle or an animal that breathes the air, somehow damage the air.

•

But when he placed a mint plant in the same bell jar, the mouse stayed alive and the candle continued to burn.

•

So, Priestley hypothesized that plants restore in the air whenever breathing animals and burning candles remove.

•

He termed the impure air as ‘phlogiston’ and the pure air as ‘dephlogiston’.

Jan Ingenhousz (1730-1799) •

He conducted a similar experiment with an aquatic plant, one kept in bright sunlight and the other in the dark.

•

He showed that in the plant that is kept in light, small bubbles were formed around the green parts, while no bubbles appeared in the plant kept in the dark.

•

Later these bubbles have been identified as oxygen bubbles.

•

He concluded that plants purify air only in presence of light.

Julius von Sachs •

He showed that the green substance (chlorophyll) is located in special bodies (chloroplasts) within plant cell.

•

He provided evidence (1854) for the production of glucose when plants grow and glucose is stored in the form of starch.

T. W. Engelmann (1843-1900) •

He determined the action spectrum of chlorophyll by using green alga, Cladophora.

•

He split the light using a prism into its component parts and illuminated a green alga, Cladophora, placed in a suspension of aerobic bacteria.

•

The bacteria were used to detect the sites of oxygen evolution.

•

He observed that the bacteria accumulated mainly in the region of blue and red light of the split spectrum. A first action spectrum of photosynthesis was thus described.

(a)

(b)

(c)

(d)

Cornelius von Niel (1897-1985) •

Based on his experiments with purple and green bacteria, he (a microbiologist) made a contribution, a milestone, in the understanding of photosynthesis.

•

He demonstrated that photosynthesis is essentially a light-dependent reaction in which hydrogen from a hydrogen-donor reduces carbon dioxide to carbohydrates. Light

2H 2 A+CO 2 → 2A+CH 2O+H 2O • • • •

In green plants, water (H2O) is the hydrogen donor and is oxidized to oxygen. Purple and green sulphur bacteria use H2S as the hydrogen donor.

He inferred that the oxygen evolved by green plants during photosynthesis comes from water (H2O) and not from carbon dioxide (CO2). This was later proved by using radioactive isotopes of oxygen (H218O). Light

6CO 2 + 12H 2O → C6 H12O6 + 6H 2O + 6O 2

Fig. 13.4 Priestley’s experiment

526

BIOLOGY Connecting Concepts

SITE OF PHOTOSYNTHESIS

 Chloroplast was first described by  Leeuwenhock (1679) and they are believed to be the site of photosynthesis  when Sach’s (1862) found starch grains inside chloroplast during photosynthesis.

Photosynthesis occur in green parts of the plants mostly in leaves and to a lesser extent in green stem or floral parts. In leaves, photosynthesis occurs particularly in specialized cells called mesophyll cells These cells contain chloroplast, which is the actual sites for photosynthesis. It fixes CO2 into carbohydrates.



Chloroplast are green coloured plastids. The entire process of photosynthesis is completed in each chloroplast.



Chloroplast are double membrane bound organelle. The space limited by the inner membrane of the chloroplast is called the stroma.



A number of organised flattened membranous sacs (called the thylakoids) are present in the stroma. Thylakoids are arranged in stacks like the piles of coins called grana.



The internal space of the thylakoid is the lumen, which is the site of oxidations of water as well as source of oxygen evolved, during photosynthesis. Lumen also serve as a reservoir for proton which are pumped across the membrane of the thylakoid during electron transport.



The thylakoids in the chloroplast contain most of the machinery for the photochemical reaction of photosynthesis. They contain pigments for capturing solar energy.



The stroma of the chloroplast contains enzymes required for the synthesis of carbohydrates & proteins.

A leaf Vascular bundle

Mesophyll cells

Cuticle Upper epidermis

Lower epidermis Substomatal Xylem Phloem cavity Outer Inner Thylakoid membrane membrane

Guard cell

Cuticle Nucleus

Vacuole Chloroplasts Stroma lamellae

Stroma

Fig.13.5 The functional organization of a leaf

PHOTOSYNTHETIC PIGMENTS 

Pigments are substances that absorb light of specific wavelengths in the visible region due to presence of conjugated double bonds in their structures.



Most of the photosynthesis takes place in the blue and red regions of the spectrum.



Photosynthetic unit can be defined as number of pigment molecules required to affect a photochemical act, that is the release of a molecule of oxygen. Park and Biggins (1964) gave the term quantasome for photosynthetic units which is equivalent to 230 chlorophyll molecules.



The quantasomes are mainly present in grana lamellae.



The various contents of quantasome are -

PHOTOSYNTHESIS





(i) Chlorophyll-a (ii) Chlorophyll-b (iii) Carotenoids (xanthophylls, carotene) A chromatographic separation of the leaf pigments shows that the colour of leaves is due to four pigments i.e. chlorophyll - a (bright or blue green in the chromatogram), chlorophyll - b (yellow green), xanthophylls (yellow) and carotenoids (yellow to yellow-orange). Chlorophyll is the major or principle pigment and carotenoids are the accessory pigment in photosynthesis.

Chlorophyll   

527

Connecting Concepts

 When central Mg atom is replaced by Chlorophyll is the main pigment, useful in photosynthesis. Fe, the chlorophyll becomes a pigment called ‘cytochrome’ which is used in Chlorophyll shows porphyrin structure. It is a large molecule composed of four 5-membered rings called pyrrole rings and a photosynthesis (photophosphorylation) central core of magnesium. A side chain, called the phytol chain extends from one of and respiration both.

the pyrrole ring.

Porphyrin ring (light absorbing 'head' of molecule)

Fig. 13.6 Structure of Chlorophyll and Carotene



Phytol chain is composed of insoluble carbon and hydrogen atoms and helps to anchor chlorophyll molecules with the thylakoids.



Chlorophyll is a green pigment because it does not absorb green light, but reflects green light, so gives green colour to the leaves.



In plants, mainly two kinds of chlorophyll (chlorophyll - a and chlorophyll - b) are present.



Chlorophyll - a is two or three times more in quantity than chlorophyll - b and acts as the reaction centre.



On absorbing light, the chlorophyll - b molecule is excited and transfers its energy to chlorophyll - a which converts the light energy into electrical energy. Thus, act as reaction centre.

528 Check Point

BIOLOGY 

Write one term for the following. 1.

Actual sites of photosynthesis.

2.

An amorphous, gel like and enzyme

Chlorophyll - a is a bluish-green while chlorophyll - b is olive-green. Both are soluble in organic solvents like alcohol, acetone etc. Chlorophyll - a (C55H72O5N4Mg) possesses –CH3 (methyl group), which is replaced by –CHO (an aldehyde) group in chlorophyll - b (C55H70O6N4Mg). Table 13.1 Differences between Chlorophyll - a & Chlorophyll - b.

rich material present within the

1.

Chlorophyll - a Chlorophyll - b Appears red in reflected light & bluish Appears brownish red in reflected light green in transmitted light. & yellow green in transmitted light.

2.

Emperical formula is C55H72O5N4 Mg. Emperical formula is C55H70O6N4 Mg.

3.

Mostly present in PS I.

Mostly present in PS II.

4.

Activated by red zone of light.

Activated by blue zone of light.

5.

Soluble in petroleum, ether solvent.

Soluble in methyl alcohol solvent.

6.

At the C-3 position of 2nd pyrrole ring, At the C-3 position of 2nd pyrrole ring, methyl (–CH3) group is present. aldehyde (–CHO) group is present.

chloroplast. 3.

Pigment which absorb light strongly in blue violet range.

4.

Term given by Parks and Biggins.

5.

Pigment mostly present in PS-II.

6.

Pigment which does not absorb green light but reflects green light.

7.

In photosynthesis, which chlorophyll molecules absorbs light energy directly.

Carotenoids 

The pigments which absorb light & transmit it to the chlorophyll reaction centre are called carotenoids.



They are sometimes called lipochromes due to their fat soluble nature. They are lipids and found in non-green parts of plants. Light is not necessary for their biosynthesis. Carotenoids mainly absorb violet, indigo and blue (maximum absorption occurs at blue region) wavelength of spectrum in higher plants and transfer it to chlorophyll - a and thus act as accessory pigments. They protect the chlorophyll molecules from photo-oxidation by picking up nascent oxygen and converting it into harmless molecular stage. Carotenoids can be classified into two groups namely-carotenes and xanthophyll.

 

Carotenes: They are orange red in colour and have general formula C40H56. They are isolated from carrot. They are found in all groups of plants i.e., from algae to angiosperms. Some of the common carotenes are α, β, γ and δ carotene; phytotene, lycopene, neurosporene etc. The lycopene is a red pigment found in ripe tomato and red pepper fruits. The β-carotene on hydrolysis gives vitamin A, hence the carotenes are also called provitamin A. β-carotene is black yellow pigment of carrot roots. (ii) Xanthophylls : They are yellow coloured carotenoid, also called xanthols or carotenols. They contain oxygen also along with carbon and hydrogen and have general formula C40H56O2. Lutein (C40H56O2) is a widely distributed xanthophyll and responsible for yellow colour in autumn foliage. Fucoxanthin (C40 H56O6) is another important xanthophyll present in phaeophyceae (brown algae). Carotenoids act as antenna complexes and harvest light from different regions of the spectrum other than chlorophyll-a, which is then funneled into the reaction centre for conversion into electrical energy. The accessory pigments and reaction centres together form photosystem. (i)





Best photosynthesis takes place in red light and then in blue light and in green light it is nil.

PHOTOSYNTHESIS

529

Absorption & Action Spectra

Connecting Concepts

If a pigment absorbs light energy, energy may be dissipated as heat or it may be emitted  The first action spectrum of immediately as a longer wavelength (the phenomenon is called flourescence) or this energy photosynthesis was studied by T.W. Engelmann (1882) using green alga may trigger a chemical reaction, as in photosynthesis.



If we study the effect of different wavelengths of light on photosynthesis and plot it on a graph paper taking wavelength of light on one hand and the rate of photosynthesis on the other it is called action spectrum of photosynthesis. Action spectra for photosynthesis and other photobiological processes help identify the pigment involved. Because these spectra often closely match the absorption spectrum of any pigment that participate.



If we take alcoholic or acetone solution of chlorophyll-a, in a test tube and provide different wavelengths of light to it and then study the transmitted light, we find that dark bands appear in red and blue regions of spectrum (in red-wider and in blue, narrow). If we plot a graph taking wavelength of light and absorption on a graph we call it absorption spectrum.



If the action spectrum of photosynthesis and absorption spectrum of chlorophyll ‘a’ solution, overlap, it is a clear indication that photosynthesis takes place only on these wavelengths absorbed by chlorophyll-a, i.e., only these wavelengths of light participate in photosynthesis, by exciting the chlorophyll molecules. Absorbance of light by chloroplast pigments



Chlorophyll b Carotenoids Chlorophyll a

Rate of photosynthesis (measured by O2 release)

Fig. 13.7 Graph showing the absorption spectrum of chlorophyll a and b

Fig. 13.8 Graph showing action spectrum of photosynthesis

Light absorbed

Rate of photosynthesis Absorption

400 500 600 700 Wavelength of light in nanometres (nm) Fig. 13.9 Graph showing action spectrum of photosynthesis superimposed on absorption spectrum of chlorophyll a

Spirogyra and oxygen seeking bacteria.

 In this case actual rate of photosynthesis in terms of oxygen evolution or carbon dioxide utilization is measured as a function of wavelength.

530

BIOLOGY

MECHANISM OF PHOTOSYNTHESIS  

Photosynthesis is actually oxidation - reduction process in which water is oxidized and CO2 is reduced to carbohydrates. The mechanism studied for photosynthesis demonstrated the existence of two phases (i)

Light phase (photochemical reaction or light reaction or Hill’s reaction or light dependent reaction).

(ii) Dark phase (biosynthetic phase or Blackman’s reaction or light independent phase or purely chemical reaction).  

 

The reduction of CO2 to carbohydrates needs assimilatory powers, i.e., ATP and NADPH2. Actual reduction of CO2 to carbohydrates is independent of light, i.e., occurs in presence or absence of light, but production of assimilatory powers (ATP and NADPH2) needs light and is light dependent. During light stage energy from sunlight is absorbed and converted to chemical energy which is stored in ATP and NADPH + H+. During dark stage carbohydrates are synthesized from carbon dioxide using the energy stored in the ATP and NADPH formed in the light dependent reactions. Table 13.2 : Differences between light & dark reaction

1.

Light reaction It is a light dependent process.

Dark reaction It does not require light.

2.

Involves photosystems - I & II.

No photosystem is required.

3.

Photolysis of water takes place & O2 is Photolysis of water does not take place. liberated. CO2 is absorbed.

4.

Occurs within chloroplast.

5.

ATP & NADPH is produced & they are Glucose is produced. Reduced NADP is used to drive the dark reaction. oxidized.

the

grana

of

the Occurs within chloroplast.

the

stroma

of

the

Light Reaction Check Point State true or false. 1.

Light phase is also called Blackman’s

2.

ATP and NADPH2 are required for the



The reaction of light phase requires light & hence called photochemical reaction.



Light reaction occurs in grana fraction of chloroplast and in this reaction are included those activities, which are dependent on light. Assimilatory powers (ATP and NADHP2) are mainly produced in this light reaction.



Transfer of energy, Emerson effect, two pigment systems, Electron transport system photolysis of water, cyclic & non-cyclic photophosphorylation), chemiosmotic hypothesis are the various events & component of light phase.

reaction. reduction of CO2 to carbohydrates. 3.

Light reactions occurs within the grana of the chloroplast.

4.

Emerson enhancement effect and red drop are the evidences in favour

Transfer of energy 

When photon of light energy falls on chlorophyll molecule, one of the electrons pair from ground or singlet state passes into higher energy level called excited singlet state. It comes back within 10–9 seconds.



This light energy, absorbed by chlorophyll molecule before coming back to ground state, appears as radiation energy, while that coming back from excited singlet state is called fluorescence and is temperature independent.

of photorespiration. 5.

Quantum requirement in photosynthesis is 8.

6.

Reaction centre of PSI is P700.

PHOTOSYNTHESIS

531

Emerson effect & Red drop 

R. Emerson and C.M. Lewis (1943) observed that the quantum yield of photosynthesis decreases towards the far red end of the spectrum (680 nm or longer) while determining the quantum yield of photosynthesis in Chlorella by using monochromatic light of different wavelengths. Quantum yield is the number of oxygen molecules evolved per light quantum absorbed. Since this decrease in quantum yield is observed at the far region or beyond red region of spectrum is called red drop.



Emerson et al. (1957) further observed that photosynthetic efficiency of light of 680 nm or longer is increased if light of shorter wavelengths (less than 680 nm) is supplied simultaneously. When both short and long wavelengths were given together the quantumyield of photosynthesis was greater than the total effect when both the wavelengths were given separately. This increase in photosynthetic efficiency (or quantum yield) is known as Emerson effect or Emerson enhancement effect. Quantum yield in combined beam – Quantum yield in red beam Quantum yield in far red beam

y

E=

Wavelength in m Fig.13.10 Red drop & Emerson’s enhancement effect in Chlorella



Therefore, rate or yield of photosynthesis is measured in terms of quantum yield On the other hand quantum requirement is defined as, “Number of quanta of light required for evolution of one molecule of O2 in photosynthesis”.



Quantum requirement in photosynthesis = 8 i.e., 8 quanta of light are required to evolve one molecule of O2.



Hence, quantum yield =

1 = 0.125 (i.e., a fraction of 1) 8

Transfer of energy

•

Photosystem (PS)-II Reaction centre is P 680

Two pigment system

Involves the following process

Photosystem (PS)-I • Reaction centre is P 700

Emerson effect and red drop

•

•

•

Light Phase Light dependent Involves photosystems (PS I and II) Occurs in grana of chloroplast.

•

•

•

•

•

•

•

•

Mechanism of ATP synthesis given by Mitchell (1961).

Chemiosmotic Hypothesis

Non-cyclic Photophosphorylation Found in green plants Involves both PS I and II. Flow of electrons is unidirectional ATP’s synthesized at one steps only.

Occurs in two ways

Photophosphorylation

Found in bacteria Involves only PS I. Flow of electrons is cyclic ATP’s synthesized in two steps

Cyclic Photophosphorylation

Photolysis of water

Divided into

Electron Transport system (formulated by Robert Hill)

Divided into two phases

Mechanism of Photosynthesis

Flow chart : Mechanism of Photosynthesis

Given by Kortschak in sugarcane (or C4 plants).

• •

Given by Melvin Calvin in C3 plants.

Dicarboxylic acid cycle (C4)

Involves two main pathway

Dark Phase Light Independent Does not involves photosysthesis Occurs in stroma of chloroplast.

Calvin cycle (C3)

•

•

•

532 BIOLOGY

PHOTOSYNTHESIS

533

Two Pigment System 

The discovery of Emerson’s effect clearly indicates that the photosynthetic pigments are organised into the discrete photochemical light harvesting complexes (LHC), called photosystem I and photosystem II.



Light reaction of photosynthesis involves participation of two separate pigment system i.e. PS I and PS II.



These are named in the sequence of their discovery, and not in the sequence in which they function during the light reaction. The LHC are made up of hundreds of pigment molecules bound to proteins. Each photosystem has all the pigments (except one molecule of chlorophyll a) forming a light harvesting system also called antennae. These pigments help to make photosynthesis more efficient by absorbing different wavelengths of light. The single chlorophyll a molecule forms the reaction centre. The reaction centre is different in both the photosystems. Table 13.3 Comparison of photosystem I and photosystem II 1.

2.

3.

4. 5. 6. 7. 8.

Photosystem I (PS - I) PS I lies on the outer surface of non appressed parts of the thylakoids (both grana & stroma thylakoids) It is not related with photolysis of water. In this system molecular oxygen is not evolved. Its reaction or photocenter is a special chlorophyll molecule called P700. Pigments absorb longer wavelengths of light (>680 nm). It participates both in cyclic and noncyclic photophosphorylation. It receives electrons from photosystem II. Main function is ATP synthesis.

Photosystem II (PS - II) PS II lies on the inner surface of the appressed parts of thylakoids (grana thylakoids). As the result of photolysis of water, molecular oxygen is evolved. Its reaction center is P680. Pigment absorbs shorter wavelength of light ( 1 156. The respiratory process of yeast is [MP PMT '10] (1) rarely anaerobic (2) anaerobic (3) purely aerobic (4) both aerobic and anaerobic 157. Which of the following processes of Krebs cycle is associated with both the processes of decarboxylation and dehydrogenation ? [Gujarat CET '10] (1) Succinate → Fumarate, Fumarate → Malate (2) Malate → Oxaloacetate, Succinate → Fumarate (3) α-ketoglutaric acid → Succinate, Malate → Oxaloacetate (4) Isocitrate → α-ketoglutaric acid, → α-ketoglutaric acid → Succinate. 158. How many ATP molecules can be produced through oxidative phosphorylation of 2NADH2 and 3 FADH2. [Gujarat CET '10] (1) 15 (2) 24 (3) 6 (4) 12 159. The energy - releasing metabolic process in which substrate is oxidised without an external electron acceptor is called: [CBSE PMT 2010] (a) glycolysis (b) fermentation (c) aerobic respiration (d) photorespiration 160. Which of the following is a 4-carbon compound? [Kerala PMT 2010] (a) oxaloacetic acid (b) phosphoglyceric acid (c) ribulose bis phosphate (d) phosphoenol pyruvate (e) citric acid 161. Oxidation of one molecule of NADH gives rise to [Kerala PMT 2010] (a) 3 ATP molecules (b) 12 ATP molecules (c) 2 ATP molecules (d) 1 ATP molecule (e) 8 ATP molecules 162. When tripalmitin is used as a substrate in respiration, the R.Q. is [Kerala PMT 2010] (a) > 1 (b) 1.0 (c) 0.9 (d) (e) 0.7 163. Pyruvate (pyruvic) dehydrogenase is used in converting [BHU'11] (1) pyruvate to glucose (2) glucose to pyruvate (3) pyruvic acid to lactic acid (4) pyruvate to acetyl coA

BIOLOGY 164. When proteins are respiratory substrate, RQ will be [HP PMT '11] (1) 0.7 (2) 1.0 (3) 0.9 (4) More than one 165. Cytochrome oxidase contain [BHU'11] (1) Fe (2) Mg (3) Zn (4) Cu 166. In respiration, pyruvic acid is [COMED-K's '11] (1) one of the products of Krebs cycle. (2) broken into two carbon fragment and CO2. (3) formed only when oxygen is available. (4) a result of protein breakdown. 167. The activity of succinate dehydrogenase is inhibited by [AFMC'11] (1) pyruvate (2) glycolate (3) malonate (4) phosphoglycerate 168. In mitochondrial electron transport system, for every two pairs of electrons that pass from NADH molecules through a sequential series of cytochrome enzymes to molecular oxygen generate [AM'11] (1) 3 ATP (2) 4 ATP (3) 6 ATP (4) 2 ATP 169. During alcoholic fermentation by yeast two molecules of glucose produce [AMU'11] (1) 2 molecules of ethanol + 2 molecules of CO2 (2) 4 molecules of ethanol + 4 molecules of CO2 (3) 6 molecules of ethanol + 6 molecules of CO2 (4) 3 molecules of ethanol + 3 molecules of CO2 170. The biological oxidation of Krebs cycle involves [Orissa JEE '11] (1) CO2 (2) NO2 (3) O2 (4) SO2 171. The number of ATP produced when a molecule of glucose undergoes fermentation is [K-CET'11] (1) 2 (2) 4 (3) 36 (4) 38 172. Which one of the following reactions is an example of oxidative decarboxylation? [K-CET '11] (1) Conversion of succinate to fumarate. (2) Conversion of fumarate to malate. (3) Conversion of pyruvate to acetyl CoA. (4) Conversion of citrate to isocitrate. 173. Enzymes of TCA cycle are present in [Orissa '10, 11] (1) ribosome (2) chloroplasts (3) mitochondria (4) nucleus 174. During respiration pyruvic acid is formed by [MP PMT '11] (1) Krebs cycle (2) TCA cycle (3) Glycolysis (4) None of these 175. RQ (Respiration Quotient) value is less than 1 in [MP PMT '11] (1) proteins (2) organic acids (3) carbohydrates (4) None of these

RESPIRATION IN PLANTS

183. An enzymes of TCA cycle are located in the mitochondrial matrix except one which is located in inner mitochondrial membrane in eukaryotes and in cytosol in prokaryotes. This enzyme is [AIIMS 2012] (a) Succinate dehydrogenase (b) Lactate dehydrogenase (c) Isocitrate dehydrogenase (d) Malate dehydrogenase 184. Consider the following statements with respect to respiration. [Kerala PMT 2012] A. Glycolysis occurs in the cytoplasm of the cell. B. Aerobic respiration takes place within the mitochondria. C. Electron transport system is present in the outer mitochondrial membrane. D. C51H98O6 is the chemical formula of Tripalmitin, a fatty acid. E. Respiratory quotient = Of the above statements (a) A, B and D alone are correct (b) B, C and D alone are correct (c) C, D and E alone are correct (d) B, D and E alone are correct (e) A, C and E alone are correct 185. Which of the metabolites is common to respiration mediated breakdown of fats, carbohydrates and proteins? [AIPMT (NEET) 2013] (1) Fructose 1, 6 - bisphosphate (2) Pyruvic acid (3) Acetyl CoA (4) Glucose - 6 - phosphate 186. The three boxes in this diagram represents the three major biosynthetic pathways in aerobic respiration. Arrows represents net reactants or products. [AIPMT (NEET) 2013] 1

glucose

176. EMP pathway occurs in the [Bihar CECE'06, Orissa Jee'07, HP PMT '11] (1) cytoplasm (2) mitochondrion (3) chloroplast (4) lysosome 177. A eukaryotic cell can synthesize only 38 ATP instead of 40 ATP if the protons of cytosolic NADH + H+ are transported into mitochondrial by [AFMC 2011] (a) malate - aspartate shuttle (b) glycerol phosphate shuttle (c) ATPase (d) permease 178. The activity of succinate dehydrogenase is inhibited by [AFMC 2011] (a) pyruvate (b) glycolate (c) malonate (d) phosphoglycerate 179. Select the wrong statement [Kerala PMT 2011] (a) when tripalmitin is used as a substrate in respiration, the R.Q. is 0.7. (b) the intermediate compound which links glycolysis with Kreb’s cycle is malic acid. (c) one glucose molecule yields a net gain of 36 ATP molecules during aerobic respiration. (d) one glucose molecule yields a net gain of 2 ATP molecules during fermentation. (e) the scheme of glycolysis was given by Embden, Meyerhof and Parnas. 180. Which of these steps in Kreb’s cycle indicates substrate level phosphorylation? [Kerala PMT 2011] (a) conversion of succinic acid to α-ketoglutaric acid. (b) conversion of succinic acid to malic acid. (c) conversion of succinyl CoA to succinic acid. (d) conversion of malic acid to oxalo acetic acid. (e) conversion of citric acid to α-ketoglutaric acid. 181. In the electron transport system present in the inner mitochondrial membrane, complexes I and IV are respectively [Kerala PMT 2011] (a) NADH dehydrogenase and FADH2 (b) FADH2 and NADH dehydrogenase (c) NADH dehydrogenase and cytochrome oxidase complex (d) NADH dehydrogenase and ATP synthase (e) cytochrome bc 1 complex and NADH dehydrogenase. 182. In the electron transport chain during terminal oxidation, the cytochrome, which donates electrons to O2 is [AIIMS 2012] (a) Cytochrome-b (b) Cyto-C (c) Cyto-a3 (d) Cyto.-f

607

9 10

5 Pathway A

2 4

Pathway B 3

6 7 8

Pathway C

11 12

Arrows numbered 4, 8 and 12 can all be : (1) ATP (2) H2O (3) FAD+ or FADH2 (4) NADH 187. 2(C51H98O6) + 145O2 → 102CO2 + 98H2O + Energy The RQ of above reaction is [AIIMS 2013] (a) 1 (b) 0.7 (c) 1.45 (d) 1.62

608 188. Assertion : The inner membrane of mitochondria contains systems involving electron transport. Reason : The mitochondrial matrix contains enzymes of Kreb’s cycle. [AIIMS 2013] (a) If both Assertion and Reason are correct and Reason is the correct explanation of Assertion. (b) If both Assertion and Reason are correct, but Reason is not the correct explanation of Assertion. (c) If Assertion is correct but Reason is incorrect. (d) If Assertion is incorrect but Reason is correct. 189. In the process of oxidative phosphorylation one molecule of NADH and one molecule of FADH2 produces [Kerala PMT 2013] (a) 2 and 3 molecules of ATP respectively. (b) 18 and 36 molecules of ATP respectively. (c) 36 and 18 molecules of ATP respectively. (d) 3 and 2 molecules of ATP respectively. (e) 2 and 36 molecules of ATP respectively. 190. Which of the following stages of aerobic respiration takes place in the matrix of the mitochondrion? [Kerala PMT 2013] I Oxidative decarboxylation of pyruvic acid II Glycolysis III Krebs cycle IV Oxidative phosphorylation (a) I and II only (b) II and III only (c) III and IV only (d) I and III only (e) I and IV only

BIOLOGY 191. Which of these statements about glycolysis is true? [Kerala PMT 2013] (a) In aerobic organisms, it is the only process in respiration. (b) In this process glucose undergoes complete oxidation to form pyruvic acid. (c) Enzyme hexokinase catalyses the phosphorylation of glucose to glucose-6 phosphate. (d) ATP is utilised in the conversion of PEP to pyruvic acid. (e) NADH + H+ is formed when 1-3 bisphosphoglyceric acid is converted to 3-phosphoglyceric acid. 192. Select the reaction of Krebs cycle resulting in substrate level phosphorylation [Kerala PMT 2013] (a) Conversion of succinic acid to malic acid. (b) Conversion of malic acid to oxaloacetic acid. (c) Conversion of succinyl - Co A to succinic acid. (d) Conversion of citric acid to a ketoglutaric acid. (e) Condensation of acetyl group with oxaloacetic acid and water to yield citric acid. 193. In which one of the following processes CO 2 is not released? [AIPMT - 2014] (1) Aerobic respiration in plants (2) Aerobic respiration in animals (3) Alcoholic fermentation (4) Lactate fermentation

RESPIRATION IN PLANTS

609

EXERCISE - 3 | Test Yourself 1. 2.

3.

Mechanism of aerobic respiration was discovered by (1) Kreb’s (2) Calvin (3) Hatch and Slack (4) Pasteur Degradation of sugar and fat to acetyl CoA will not take place if the following organelle is not present in a eukaryotic cell. Identify the organelle. (1) Golgi apparatus (2) Mitochondrion (3) Ribosome (4) Nucleus The given figure shows the fate of glucose during aerobic and anaerobic respiration. Identify the end products that are formed at stages indicated as A, B, C and D. Identify the correct option from those given below. Glucose A

7.

8.

9. 10. 11.

Pyruvic acid

Presence of Oxygen

Absence of Oxygen

Kreb’s Cycle B

4.

5. 6.

12.

Fermentation

C

Yeast

Lactic acid

D

(1) A = ETS, B = pyruvic acid, C = ethyl alcohol and carbon dioxide, D = lactic acid. (2) A = glycolysis, B = carbon dioxide and water, C = bacteria, D = ethyl alcohol and carbon dioxide. (3) A = pyruvic acid, B = carbon dioxide and water, C = ethyl alcohol and lactic acid, D = fungi. (4) A = ETS, B = ethyl alcohol and carbon dioxide, C = lactic acid, D = carbon dioxide and water. If a starved plant is provided with glucose, the rate of respiration would (1) decrease (2) increase (3) become constant (4) first rise and than fall In plants, energy is produced during the process of (1) transpiration (2) respiration (3) photosynthesis (4) water absorption Enzymes related with cristae are related with (1) anaerobic respiration (2) aerobic respiration (3) CO2 formation (4) reduction of pyruvic acid

13.

14.

15.

16.

17.

In oxidative phosphorylation, oxidation and phosphorylation take place simultaneously and form (1) NADP (2) DPN (3) pyruvic acid (4) ATP The formula for the process of glycolysis is (1) C6H12O6 → 2C3H3O3 + 4H (2) C6H12O6 + 6CO2 → 6CO2 + 6H2O (3) 6H2O + 6CO2 → 6CO2 → 6O2 (4) None of the above The oxidation of one NADH2 yields (1) 18 ATP (2) 6 ATP (3) 3 ATP (4) 2 ATP Which of the following process occurs in glycolysis ? (1) Oxidation (2) Reduction (3) Hydrogenation (4) Fixation Most of the energy in the cell is liberated by oxidation of carbohydrate when (1) pyruvic acid is converted into CO2 and H2O. (2) pyruvic acid is converted into acetyl CoA. (3) sugar is converted into pyruvic acid. (4) glucose is converted in alcohol and CO2. Largest amount of phosphate bond energy is produced in the process of respiration during (1) anaerobic respiration (2) glycolysis (3) Kreb’s cycle (4) None of the above In how many steps, CO2 is released in aerobic respiration of pyruvic acid ? (1) One (2) Six (3) Three (4) Twelve The formation of acetyl coenzyme-A from pyruvic acid is the result of its (1) reduction (2) dehydration (3) dephosphorylation (4) oxidative decarboxylation Cytochrome helps in (1) oxidation of glucose (2) release of energy (3) electron transport (4) growth Aerobic respiration which yields maximum ATP molecules is completed on (1) mitochondria (2) general cytoplasm (3) general cytoplasm and mitochondria (4) somewhere else Mineral activator needed for the enzyme carboxylase of TCA cycle is (1) Mg++ (2) Fe+++ ++ (3) Mo (4) Mn++

610 18.

19.

20.

21.

22.

23.

24.

25.

26.

27.

28.

29.

BIOLOGY In an electron transport chain in terminal oxidation the cytochrome which donates electrons to O2 is (1) cytochrome b (2) cytochrome c (3) cytochrome a3 (4) cytochrome a The correct sequence of electron acceptor in ATP synthesis is (1) Cyt a3, a, b, c (2) Cyt b, c, a, a3 (3) Cyt b, c, a3, a (4) Cyt c, b, a, a3 Which of the following is important in electron transport system ? (1) Ubiquinone (2) Acetyl CoA (3) Tricarboxylic acid (4) Ferricyanide Which can accept a hydride ion during electron transduction system ? (1) FADH, NADH (2) FAD+, NADP+ + (3) FAD , NADH (4) FADH, NAD+ Which of the following is not an intermediate of Kreb’s cycle ? (1) Acetyl Co-A (2) Citric acid (3) Succinic acid (4) Lactic acid In which of the following process 36 ATP molecules are produced by per hexose molecule ? (1) Glycolysis (2) Kreb’s cycle (3) Direct oxidation pathway (4) None of the above In pentose phosphate pathway which process is lacking ? (1) Kreb’s cycle (2) Glycolysis (3) Oxidative phosphorylation (4) None of the above RQ of fatty substances is generally (1) unity (2) less than one (3) greater than one (4) zero Which of the following is non-enzymatic phosphorylation ? (1) Formation of fructose 1, 6-diphosphate. (2) Formation of dihydroxyacetone phosphate. (3) Formation of 1, 3-diphosphoglyceraldehyde. (4) All of the above In the process of respiration in plants 180 gms of sugar plus 192 gms of oxygen produce (1) large amount of CO2, no water and no energy. (2) 132 gms of CO2, 54 gms of water and 337 kcals of energy. (3) 264 gms of CO2, 108 gms of water and 674 kcals of energy. (4) 528 gms of CO2, 216 gms of water and 1348 kcals of energy. How many ATP will be produced during the production of 1 molecule of acetyl CoA from 1 molecule of pyruvic acid ? (1) 3 ATP (2) 5 ATP (3) 8 ATP (4) 38 ATP R.Q. is highest when respiratory substance is (1) fat (2) malic acid (3) glucose (4) protein

30.

31.

32.

Fermentation is cond conducted by (1) all fungi (2) all bacteria (3) some fungi and some bacteria (4) all micro-organisms What will happen to glycolytic pathway if a cell runs completely out of ATP ? (1) Glycolysis will speed up. (2) Glycolysis will be slow down. (3) Glycolysis will stop as first and third steps need ATP input. (4) Glycolysis will increase as energy will be supplied by NADH2. Refer the figure and answer the question. Glucose

ATP

ADP Glucose-6 – Phosphate P

R

Q

NAD + NADH + H + S 2 × 3 PGA 2 × 2 PGA

H2O PEPA ADP ATP 2 × C3H4O3

Choose the correct names of P, Q, R, and S. P (1) (2) (3) (4) 33.

(1) (2) (3) (4)

Q

1,3 di PGA 3 PGA1d Fr. 1,6 di P Fr.6 P

3 PGAld 1,3 di PGA Fr. 6 P Fr. 1,6 di P

R

S

Fr.1,6 di P Fr. 1,6 di P 3 PGAld 3 PGAld

Fr. 6 P Fr.6 P 1,3 di PGA 1,3 di PGA

At the end of glycolysis X is the net energy gain from one molecule of glucose via Y, but there is also energy stored in the form of Z. Identify X, Y and Z from the given options. X

Y

Z

1ATP 2ATPs 2ATPs 2ATPs

Oxidative phosphorylation Oxidative phosphorylation Substrate level phosphorylation Substrate level phosphorylation

NADH + H+ NADH + H+ NADPH + H+ NADH + H+

34. In Kreb’s cycle, the first product is citric acid which is a 6-carbon compound. It is formed by a condensing irreversible reaction between (1) OAA and pyruvic acid (2) OAA and acetyl coenzyme A (3) pyruvic acid and acetyl coenzyme A (4) OAA and citrate synthetase

RESPIRATION IN PLANTS 35.

36.

37.

38.

39.

611

All of the following processes can release CO2 except (1) alcohol fermentation (2) oxidative decarboxylation and Kreb’s cycle (3) oxidative phosphorylation (4) α-Ketoglutaric acid → succinic acid Which of the following is not true for oxidative phosphorylation? (1) It uses oxygen as the initial e– donor. (2) It involves the redox reactions of electron transport chain. (3) It involves an ATP synthase located in the inner mitochondrial membrane. (4) It depends on chemiosmosis. The electron carrier molecules and cytochrome (1) are reduced as they pass electrons on to the next molecule. (2) transfer electrons between the electron carrier complexes. (3) shuttle protons to ATP synthase. (4) are found in outer mitochondrial membrane. Which of the following statement(s) is/are incorrect ? I. Proton channel of oxysome / complex V / ATP synthase is located in F1. II. Metabolic water is water produced in terminal oxidation / produced in respiration. III. CoQ accepts electron from NADH dehydrogenase (complex I) and also can accept electron from FADH2/ succinate Q-reductase / complex II. IV. Cytochrome c is a small protein attached to outer surface of the inner mitochondrial membrane and acts as mobile carrier for transfer of electrons between complex I (Cyt bc, complex) and III. V. Complex IV refers to cytochrome c oxidase (cyt a, a3 and 2 Cu per centre). VI. If a cell is treated with a drug that inhibits ATP synthase, the pH of mitochondrial matrix will increase. (1) I, II, III (2) III, V, VI (3) I and IV (4) Only III Which of the following diagram represents ATP synthesis in mitochondria through chemiosmosis? I.M. = Inner membrane; M = Matrix ; O.C. = Outer Chamber ADP + iP 2e– ATP

(1) 2e– OC

M

ADP + iP 2e– ATP

(2) 2e– OC

M IM

OC

M IM ADP + iP 2H+ ATP

(4) 2H+ OC

M IM

40.

Which of the following statement is false? I. Fermentation is partial breakdown of glucose but aerobic respiration is the complete breakdown of glucose in CO2 + H2O. II.

NADH + H +  → NAD + Very slow Fermentation

+ → NAD + III. NADH + H  Aerobic respiration Very slow

IV. In respiratory pathway glycerol changes into NDAH. (1) None of the above (2) All of the above (3) IV (4) III and IV The figure indicates the interrelationship among metabolic pathways. Now identify A to D.

41.

A Fatty acids and glycerol

Carbohydrates

C

Simple sugars e.g. Glucose

Amino acids

Glucose 6-phosphate Fructose 1,6 bisphosphate B

Glyceraldehyde 3-phosphate

Pyruvic acid D H2O

(1) (2) (3) (4) 42.

IM IM

ADP + iP 2H+ ATP

(3) 2H+

Krebs' cycle

CO 2

A B C D Protein Acetyl CoA Fat DHAP Fat DHAP Protein Acetyl CoA Acetyl CoA Fat DHAP Protein Fat DHAP Acetyl CoA Protein 2(C51H98O6) + 145O2 → 102CO2 + 98H2O + Energy The RQ of above reaction is (1) 1 (2) 0.7 (3) 1.45 (4) 1.62

612 43.

BIOLOGY The diagram below refers to mitochondnrial electron transport chain. Identify P, Q, R, S, T. Inner Mitochondria Q P Membrane

46.

R

T

2H 2H MN F

S

47.

–

2e FeS T

UQH2

FeS 2e– UQ

T

–

48.

2e Cyt b 2e– FeS –

2e UQ

T

2e– Cyt c1

T

49.

½O2 –

2e Cyt c Cyta-a3

+

2H H2O

(1) P - Matrix; Q - Outer membrane R - FMNH2; S - NAD2; T – 2H (2) P - Outer chamber; Q - Matrix; R - NADH + H+; S - NAD+; T – 2H+ (3) P - Outer membrane; Q - Cristae; R - NAD+; S - NAD+; T – 2H+ (4) P - Cristae; Q - Outer chamber; R - NADH + H+; S - NAD+; T - 2H+ 44. In mitochondria, protons accumulate in the (1) outer membrane (2) inner membrane (3) intermembrane space (4) matrix Direction (45 to 46) : In the following questions more than one of the answer given may be correct. Select the correct answer and mark the answer according to the codes given. Codes : (1) (a), (b) and (c) are correct. (2) (a) and (b) are correct. (3) (b) and (d) correct. (4) (a) and (c) are correct. 45. ATP (a) has high energy containing first phosphate bond. (b) is produced by oxidative phosphorylation and photophosphorylation. (c) acts as energy mediator in the cell. (d) has low energy containing second and third phosphate bond.

50.

51.

52.

During Kreb’s cycle (a) acetyl Co-A combines with 4 carbon oxaloacetic acid to produce 6 carbon citric acid. (b) malic acid undergoes reduction to produce oxaloacetic acid. (c) in presence of Mn2+ and dehydrogenase enzyme, α-ketoglutaric acid is converted into succinyl CoA. (d) in presence of α-ketoglutaric acid dehydrogenase enzyme, α-ketoglutaric acid is converted into oxaloacetic acid. Which one of the following attaches phosphate groups to sugar molecules ? (1) Adenosine diphosphate (ADP) (2) Adenosine triphosphate (ATP) (3) Glucose-1-phosphate (4) Phosphorylase Which of the following types of mammalian cell does not carry out oxidative phosphorylation? (1) Cardiac muscle cells (2) Erythrocytes (3) Neurons (4) Oxyntic cells Where are the enzymes located which are involved in the chemical reactions which occur during glycolysis? (1) In the fluid matrix of cytoplasm. (2) In the mitochondrial matrix. (3) In the nuclear sap. (4) On the cristae of a mitochondria. Six tubes containing preparations from animal tissue were set up as shown in the table. Tube contents A. glucose + homogenised cells B. glucose + mitochondria C. glucose + cytoplasm lacking organelles D. pyruvic acid + homogenised cells E. pyruvic acid + mitochondria F. pyruvic acid + cytoplasm lacking organelles After incubation, in which three tubes would carbon dioxide be produced? (1) A, B and C (2) A, D and E (3) C, D and F (4) C, E and F What is the final pathway followed by all carbon atoms derived from carbohydrates, lipids and proteins when they are oxidised during respiration? (1) Calvin cycle (2) Electron transport system (3) Krebs cycle (4) Ornithine cycle The diagram shows stalked particles on part of a crista membrane in a mitochondrion.

a inner membrane sphere b matrix c base

What occurs in each of the numbered regions?

RESPIRATION IN PLANTS

613

a 1.

ADP synthesis ADP synthesis ATP synthesis ATP synthesis

2. 3. 4. 53.

b

c

Electron transport Glycolysis

Krebs cycle

Krebs cycle

Electron transport Glycolysis

Krebs cycle

Krebs cycle

56. 57.

58.

The diagram summarises the pathway of glucose breakdown. Hexose A Triose phosphate B Pyruvate

C

lactate

Acetyl CoA

54.

55.

D 6C compound E H 2 O + CO2 When two steps result in a net increase of ATP? (1) A and C (2) A and D (3) B and D (4) B and E Which of the following pathways outlines the order of events during aerobic cellular respiration? first → last (1) glucose → triose phosphate → pyruvate → Krebs cycle → CO2 + H2O + ATP (2) glucose → triose phosphate → pyruvate → Krebs cycle → CO2 + H2O + ADP + Pi (3) glucose → hexose phosphate → pyruvate → Krebs cycle → CO2 + H2O + ADP + Pi (4) glucose → hexose phosphate → pyruvate → Krebs cycle → ethanol + CO2 + ATP The diagram shows the reversible conversion of pyruvate to lactate by the enzyme lactate dehydrogenase. NAD reduced CH3 NAD CH3

C=O

59.

60.

61.

62.

CHOH

NAD COO – reduced lactate NAD What would be the effect of inhibition of lactate dehydrogenase in a mammalian cell under anaerobic conditions? (1) A decrease in cell pH, due to the accumulation of lactic acid. (2) A decrease in glycolysis, due to the lack of NAD. (3) An increase in ATP production, due to increased amounts of reduced NAD. (4) An increase in the activity of the Krebs cycle, due to increased amounts of pyruvate. COO – pyruvate

63.

All are products of anaerobic respiration except (1) ethyl alcohol (2) lactic acid (3) fumaric acid (4) butyric acid Which of the following substances is not an essential component of the tricarboxylic acid cycle? (1) FAD (2) Succinyl CoA (3) NADP (4) Citric acid Certain organism are allowed to respire anaerobically for some time. If they are transferred to an oxygen containing medium, the rate of aerobic respiration of these organisms is always faster as compared to the rate of respiration of organisms which are given O2 since the beginning. This might be due to which one of the following reasons? (1) Due to faster rate of oxidation, the end products accumulate in the aerobic organisms reduces the rate of its respiration. (2) In anaerobically respiring animals, there are extra enzymes to increase the rate of the oxidation. (3) In anaerobically respiring animals, the end product produced is common with that of aerobic respiration and therefore the rate of oxidation is hastened. (4) In aerobically respiring organisms, an intermediate product of anaerobic respiration is further oxidized. In some succulent plants like Opuntia the R.Q. is zero because (1) CO2 is released without any absorption of O2. (2) O2 is absorbed but CO2 is not released. (3) there is often compensation point in these plants due to thick phylloclades. (4) none of the above. Hexose monophosphate shunt does not take place when (1) oxygen is not enough. (2) glucose is the substrate. (3) NAD is available. (4) NAD is not available due to shortage of oxygen. Fermentation is essentially glycolysis plus an extra step in which pyruvic acid is reduced to form lactic acid or alcohol and CO2. This last step (1) removes poisonous oxygen from the environment. (2) extracts a bit more energy from glucose. (3) enables the cell to recycle NAD+. (4) inactivates toxic pyruvic acid. A microbiologist discovered a new antibiotic that slowed the growth of bacteria by interfering with cellular respiration. She found that bacteria treated with the antibiotic produced about 15 ATP molecules for every glucose molecule they consumed. Which of the following hypothesis could explain the antibiotic’s effect? The treated bacteria (1) cannot perform glycolysis. (2) have partially crippled electron transport chains. (3) cannot produce NADH. (4) have to rely atleast partially on biosynthesis for their ATP. The major reason that glycolysis is not as energy productive as respiration is that (1) NAD+ is regenerated by alcohol or lactate production, without the high-energy electrons passing through the electron transport chain.

614

64.

65.

BIOLOGY (2) it is the pathway common to fermentation and respiration. (3) it does not take place in a specialized membranebound organelle. (4) pyruvate is more reduced than CO2; it still contains much of the energy from glucose. The electron carrier molecules Q and cytochrome c (1) are reduced as they pass electrons on to the next molecule. (2) contain heme prosthetic groups. (3) shuttle protons to ATP synthetase. (4) are mobile carriers that transfer electrons between the electron carrier complexes. Which of the following reactions is incorrectly paired with its location ? (1) ATP synthesis/inner membrane of the mitochondrion. (2) Fermentation/cell cytosol

66.

67.

(3) Glycolysis/cell cytosol (4) K Krebs cycle/cristae of mitochondrion Which of the following conversions represents a reduction reaction ? (1) Pyruvate → acetyl CoA (2) C6H12O6 → 6CO2 (3) NADH + H+ → NAD+ + 2H (4) Acetaldehyde (C2H4O) → ethanol (C2H6O) Electron transport chain is inhibited by (1) rotenone and amytal (2) antimycin-A (3) cyanide (CN – ), azide (N3 –) and carbon monoxide (CO) (4) all of the above

RESPIRATION IN PLANTS

615

ANSWER KEY 1. 6. 11. 16. 21. 26. 31. 36. 41.. 46. 51. 56. 61.

EXERCISE 1 : NCERT BASED QUESTIONS (2) 2. (2) 3. (2) 4. (2) 5. (3) 7. (2) 8. (3) 9. (3) 10. (1) 12. (3) 13. (3) 14. (3) 15. (1) 17. (4) 18. (2) 19. (3) 20. (1) 22. (2) 23. (3) 24. (1) 25. (4) 27. (2) 28. (1) 29. (2) 30. (3) 32. (2) 33. (4) 34. (4) 35 (2) 37 . (2) 38. (3) 39. (3) 40. (1) 42. (2) 43. (3) 44. (4) 45. (1) 47. (4) 48. (3) 49. (1) 50. (2) 52. (3) 53. (2) 54. (2) 55. (4) 57. (2) 58. (3) 59. (1) 60. (4) 62. (3) 63. (2) 64. (2) 65.

66.

(1)

67.

(1)

68.

(4) (4) (4) (2) (3) (4) (4) (1) (1) (2) (3) (3) (2)

(2)

EXERCISE 2 : WINDOW TO COMPETITIVE EXAMS 1. 6. 11. 16. 21. 26. 31. 36. 41. 46. 51. 56. 61. 66. 71. 76. 81. 86. 91. 96. 101. 106. 111. 116. 121. 126. 131. 136. 141. 146. 151. 156.

(4) (4) (1) (1) (1) (2) (3) (2) (4) (3) (2) (3) (2) (3) (2) (4) (1) (2) (4) (4) (2) (3) (2) (2) (2) (2) (1) (2) (5) (1) (3) (4)

2. 7. 12. 17. 22. 27. 32. 37. 42. 47. 52. 57. 63. 67. 72. 77. 82. 87. 92. 97. 102. 107. 112. 117. 122. 127. 132. 137. 142. 147. 152. 157.

(4) (3) (1) (1) (2) (4) (2) (1) (3) (2) (2) (3) (2) (3) (2) (1) (1) (4) (3) (1) (2) (3) (1) (2) (4) (1) (2) (3) (4) (2) (1) (4)

3. 8. 13. 18. 23. 28. 33. 38. 43. 48. 53. 58. 63. 68. 73. 78. 83. 88. 93. 98. 103. 108. 113. 118. 123. 128. 133. 138. 143. 148. 153. 158.

(1) (4) (2) (1) (4) (3) (3) (2) (2) (3) (2) (3) (1) (3) (1) (2) (4) (1) (1) (3) (2) (2) (3) (4) (4) (2) (4) (2) (2) (1) (4) (4)

4. 9. 14. 19. 24. 29. 34. 39. 44. 49. 54. 59. 64. 69. 74. 79. 84. 89. 94. 99. 104. 109. 114. 119. 124. 129. 134. 139. 144. 149. 154. 159.

(4) (4) (3) (2) (4) (4) (1) (2) (2) (2) (1) (1) (3) (2) (3) (3) (2) (2) (1) (1) (1) (4) (2) (2) (2) (1) (1) (2) (1) (1) (1) (2)

5. 10. 15. 20. 25. 30. 35. 40. 45. 50. 55. 60. 65. 70. 75. 80. 85. 90. 95. 100. 105. 110. 115. 120. 125. 130. 135. 140. 145. 150. 155. 160.

(4) (2) (1) (3) (3) (1) (4) (3) (4) (3) (4) (1) (4) (2) (3) (4) (2) (1) (1) (4) (4) (2) (4) (2) (2) (4) (3) (3) (4) (3) (1) (1)

161. 166. 171. 176. 181. 186. 191.

(1) (2) (1) (1) (3) (1) (3)

162. 167. 172. 177. 182. 187. 192.

(5) (3) (3) (2) (3) (2) (3)

163. 168. 173. 178. 183. 188. 193.

(4) (3) (3) (3) (1) (2) (4)

164. 169. 174. 179. 184. 189.

(3) (2) (3) (2) (1) (4)

165. 170. 175. 180. 185. 190.

(1) (3) (1) (3) (3) (4)

EXERCISE 2 : WINDOW TO COMPETITIVE EXAMS 6. (a) 19. (a) 178. (3) 179. (1) 3. (c) 1. (1) 2. (2) Because Kreb’s cycle occurs in matrix of mitochondria. 3. (2) 4. (2) 5. (2) Oxidation of organic compounds by respiration, resulting in the release of chemical energy, water and CO2. 6. (2) 7. (4) 8. (1) C6H12O6 is glucose and C3H4O3 is pyruvic acid. 9. (3) The oxidation of one NADH2 yields 3 ATP and one FADH5 yields 2 ATP molecules. 10. (1) 11. (1) 12. (3) Largest amount is ATP is produced during aerobic respiration (38 ATP). It includes 8 ATP in glycolysis and 30 ATP in kreb’s cycle. 13. (3) In aerobic respiration, CO2 is produced at 3 step : (i) During acetyl Co-A formation. (ii) During formation of α-ketogluatric acid in Kreb’s cycle. (iii) During succinic acid formation in Kreb’s cycle. 14. (4) 15. (3) 16. (1) 17. (1) 18. (3) Cytochrome a3 is terminal cytochrome of ETC. It has Fe+++ and Cu++ both. With Fe+++, it picks up electrons and through Cu+ it passes electrons to oxygen. 19. (2) These are arranged in order of their increasing redox potential and electron flow through the chain in step wise manner from the more electronegative compound to the more electropositive O2. On the basis of redox potential cytochrome acceptor order is cyt b, c, a, a3. 20. (1) Ubiquinone enzyme and cytochrome are not bound to stalked particles but act as mobile electron carriers between the complexes. 21. (2) 22. (4) 23. (3) The complete oxidation of one glucose molecule forms 12NADPH which are equivalent to 36 ATP molecules. 24. (2) Because in PPP, glucose 6-phosphate is directly oxidized without entering glycolysis.

616 25. 27.

BIOLOGY

31. 36. 41. 46.

(2) 26. (3) (3) Reaction of respiration is C6H12O6 + 6O2 → 6CO2 + 6H2O + 674 kcal In this reaction considering molecular weight of each element, we get C6H12O6 = 6 times 12 + 12 times 1 + 6 times 16 = 180 gm O2 = 6 times 32 = 192 gm Now we consider products of this reaction i.e. 6CO2 and 6H2O 6CO2 = 6 (12 + 32) = 264 gm 6H2O = 6 (2 + 16) = 108 gm (1) During acetyl CoA formation by pyruvic acid, only one NADH2 is formed by which 3 molecules of ATP are formed. (2) Because malic acid is an organic acid, which after oxidation produces more CO2, due to which the value of R.Q. is four. (3) Fermentation is anaerobic breakdown of carbohydrates into alcohol, organic acids with the help of microorganisms (fungi, bacteria). (3) 32. (4) 33. (4) 34. (2) 35. (3) (1) 37. (2) 38. (3) 39. (3) 40. (3) (2) 42. (2) 43. (2) 44. (3) 45. (2) (4)

47.

(3)

The enzyme phosphorylase attaches an inorganic phosphate molecule to sugar molecules, forming glucose 48-phosphate. This process occurs during glycolysis.

48.

(2)

Oxidative phosphorylation is the addition of a phosphate group to ADP using the energy gained from electron transfer along a chain of electron carriers. This process generates energy in the form of ATP, and is absent in erythrocytes.

28.

29.

30.

49.

50.

51.

(1)

(2)

(3)

Glycolysis occurs in the cytosol, where the glucose molecule is converted into two molecules of the three-carbon compound, pyruvate. The enzymes are located here. Glucose and pyruvic acid serve as sources of substrates which the homogenised cells can oxidise in glycolysis and Krebs cycle respectively. Mitochondria however, can only oxidize pyruvic acid via the Krebs cycle. The Krebs cycle is a complex of nine reactions where two molecules of acetyl CoA are oxidized to CO2.

52.

(3)

53.

(4)

54.

(1)

55.

(2)

56.

(3)

57.

(3)

58.

(4)

59.

(2)

The electron transport system occurs in 3, and is coupled to proton transport across the inner membrane (1), generating the proton-motive force, powering ATP synthesis. Krebs cycle occurs in the matrix, where two molecules of acetyl CoA are oxidized. ATP formation occurs both at 2, where glyceraldehyde-3-phosphate is converted to pyruvate; and at 5, where the six-carbon compound, citrate, releases water and CO2 in the Krebs cycle. Glucose is converted to hexose phosphate, which is broken down to triose phosphate, which is subsequently converted to pyruvate. Pyruvate enters the Krebs cycle, producing carbon dioxide, reduced NAD and ATP. Reduced NAD enters the electron transport chain, where oxygen is reduced to water and ATP is produced. One of the functions of the electron transport chain and the conversion of pyruvate to lactate is the regeneration of NAD from reduced NAD. NAD is needed in glycolysis. Fumaric acid is not a product of anaerobic respiration. It is an intermediate compound of aerobic respiration (Krebs cycle). NADP is a coenzyme of dehydrogenases participating in photosynthesis and pentose phosphate pathway. In TCA cycle the coenzyme is either NAD or FAD. Anaerobic respiration produces pyruvic acid which is the raw material for aerobic oxidation. So if the organism was already producing pyruvic acid it will hasten the rate of Krebs cycle. In succulent plants like Opuntia there is an incomplete oxidation of the carbohydrates resulting in the formation of organic acids. CO2 is not released. 2C6H12O6 + 3O2 → 3C4H6O5 + 3H2O + 386 kcal. R.Q.=

60.

61. 62.

63.

(3)

CO 2 0 = = 0 O2 3

When oxygen is available NADH2 produced in EMP-Krebs cycle pathway is released in the form of NAD. When there is shortage of oxygen NAD is not available and NADP takes up its place. (3) The last step regenerates NAD+ from NADH and H+. (2) Without the electron transport system, there is the net production of only 2 ATP. With a fully functional electron transport system, an additional 36 ATP may be produced. (4) 64. (4) 65. (4) 66. (4) 67. (4)

15

Chapter

Plant Growth and Development While going through the chapter pay special attention to the following – Terms & definitions – 1. Relative growth rate 2. Absolute growth rate 3. Plasticity Flow charts – 1. Growth in unicellular & multicellular animals 2. Germination of seeds to its senescence 3. Role of auxin in cell enlargement Tables – 1. Growth & Development 2. A brief detail on plant hormones, their functions & locations Name of bioassays of phytohormones – auxin, cytokinin, gibberellin, ethylene & ABA. Check points – For topicwise revision.

At a Glance            

Introduction Growth

Plant Growth Generally is Indeterminate Growth is Measurable Phases of Growth Growth Rates

Conditions for Growth

Differentiation, De-differentiation & Re-differentiation Development

Plant Growth Regulators

Discovery of Plant Growth Regulators

Physiological Effects of Plant Growth Regulators



Growth occurs when new cells and tissues are formed by cell division followed by cell enlargement.



(ii) Gibberellin Development is a process in which cells change form & functions to form the specialized (iii) Cytokinin tissues, organ & structure required during the life cycle of plant. It commences with the first cell division after fertilization of the ovule & continues through seed development, seed (iv) Ethylene germination, the development of the seedlings to the mature plant, flowering & production (v) Abscisic Acid of next generation of ovules. It also include the processes of cell death & senescence. During  Photoperiodism this period, a complex body organisation is formed that produces roots, leaves, branches,  Vernalization flowers, fruits & seeds & finally dies.  Seed Dormancy

Fig. 15.1 Germination and seedling development in bean.

(i) Auxin

618

BIOLOGY

GROWTH 

Growth is a characteristic cteristic ffeature of all living organisms.



Growth is the final product of successful metabolism i.e., during growth, anabolic process dominate over the catabolic process.



Growth of plants is generally confine to the meristems i.e., shoot tip and root tip. Growth is a quantitative phenomenon and can be measured in relation to time.



Growth is defined as a “permanent or irreversible increase in dry weight, size or volume of a cell and organ or organism”.



The growth in living organisms is intrinsic which results in the addition of living protoplasm due to metabolic activities in the living cells.



The growth that takes place between seedlings emergence & flower initiation in a plant is called vegetative growth. Vegetative growth takes place in vegetative parts of the plants. Reproductive growth constitutes initiation of flowering, development of sex organs, fertilization and seed formation.

Plant Growth Generally is Indeterminate 

Plant growth is unique because plants retain the capacity for unlimited growth throughout their life. This ability of plants is due to the presence of meristems at certain locations in their body. The cells of such meristems have capacity to divide and self perpetuate. These cells later form plant body when they loose the capacity of dividing.



Some plant structures are determinate others are indeterminate. A determinate structures grows to a certain size and then stops, eventually undergoing senescence & death (e.g. leaves, flowers and fruits). On the other hand, the vegetative stems and roots are

Shoot apical meristem

indeterminate structures. They grow by meristems that continuously replenish themselves. When an indeterminate vegetative meristem becomes reproductive (i.e., begins to form a

Shoot

Root

Vascular cambium

flower), it becomes determinate. 

There are three meristematic regions in plant i.e., apical, intercalary and lateral.



Apical meristems : The two important growing points are present in the root apex and stem apex called root apical meristem and shoot apical meristems respectively.

Vascular cambium

They are responsible for the elongation of the plant parallel to its axis. Such growth is known as primary growth. Primary growth results in the formation of tissue of a plant, the increase in the length of the plant, and the differentiation of various appendages.

Root apical meristem Fig.15.2 Diagrammatic representation of locations of root apical meristem, shoot apical meristem and vascular cambium. Arrows exhibit the direction of growth of cells and organ.



Intercalary meristems : Intercalary meristems are actually a part of apical meristems, which get separated from the apex by intervening permanent tissues. These meristems are of a temporary nature. In some plants, increase in length is due to intercalary meristems, e.g., bamboo, mint etc.

PLANT GROWTH AND DEVELOPMENT 

619

Lateral meristems : The lateral meristem (cambium) add new tissues for growth in thickness. It causes increase in girth of the organs in which they are active. This type of growth is called as secondary growth.

 Direct method: The length of plant and plant organ is measured directly with the help of ordinary measuring scale at a particular interval of time.

Growth In Unicellular plants • Growth occurs all over the body. • It is not restricted to a region.

Multicellular plants Growth is restricted to some specific region (called meristems).

On the basis of meristem, it is of three types.

Apical meristem • Terminal in position. • Responsible for apical growth. • E.g., root & shoot apices. • Also called primary growth.

Intercalary meristem • Responsible for localized growth. • At bases of nodes or internodes. • E.g., bamboo, mint.

Connecting Concepts  Methods employed to measure primary growth.

 Horizontal or travelers microscope: It is used to measure growth in fields.  Auxanometer : This equipment is used for precise measurement of plant growth. An auxanometer is used to measure the growth of a plant in terms of shoot length. It is of two types – (i) Arc auxanometer : A thread is tied to the growing tip of potted plant, and at the other end, a weight is tied after passing the thread over a pulley. The needle attached in the centre of the pulley will show the deflection, which can be read on the graduated arc to find out the increase in length of the plant.

Lateral meristem or cambium The actual growth in length • Divide radially The distance • Responsible for lateral Radius of pulley travelled by pointer or secondary growth. = Length off pointer measured from the centre of pulley

(ii) Pfeffer’s auxanometer : The Pfeffer’s auxanometer consists of two wheels i.e., Flow Chart 15.1 Growth in Unicellular & Multicellular plants. one small and one big. Smaller wheel is attached to the central axis of bigger Growth is Measurable wheel. A thread that is tied to the stem tip  The growth in plants can easily be measured in terms of increase in surface area (e.g., is hanged on small wheel. A small weight leaf), in length or girth (e.g., pollen tube), increase in weight (both fresh and dry), and is tied on the other end of this thread. On volume of an organ of plant. the bigger wheel a thread is hanged and its both ends are tied with small weights.  The increase in number of cells (especially in algae, yeast and bacteria) also gives an idea A pointer is attached to this thread which about the rate of growth. is made to contact a smoked paper.



Single maize root apical meristem can give rise to more than 17,500 new cells per hour, As plant grows and the two wheels watermelon may increase in size upto 3,50,000 times. move downward the pointer moves

in such a way that a spiral line goes on forming on the smoke paper. The Phases of Growth perpendicular distances between two  The period of growth is generally divided into three phases i.e., merismatic or formative adjoining marking indicates the hourly (phase of cell division), elongation (phase of cell elongation) and maturation (phase growth of plants.



The primary work on growth measurement was done by Sachs (1873).

of cell maturation).



 Crescograph : It is a sensitive devise, devised by J.C. Bose. It records primary Meristematic phase : This phase is also called formative phase. It has constantly growth very accurately. It magnifies dividing cells and is restricted to the apical meristems, both at the root and shoot tips. The growth upto 10,000 times giving meristematic cells in the growth tips are thin walled. They have very dense protoplasm information of growth per second.

with very small vacuoles. The cells are isodiametric and do not have intercellular spaces. They have large nuclei which are centrally located. Some elongation of the cells takes place during cell division but very small compared to that of phase of elongation. 

Elongation phase : It lies just behind the formative phase and is aimed at the enlargement of cells. The rich amount of solutes, present in these cells, cause absorption of water. As

620

BIOLOGY water diffuses into cell certain solutes are also absorbed. This further increases the growing cell’s osmotic pressure, which is essential for maintaining a high turgor pressure. The turgor pressure stretches the wall of growing cell. During cell enlargement, a large vacuole appears in the centre and the protoplasm occupies the peripheral region of cell.



Some explanations have been given to explain the cell wall elongation. According to one theory new particles of cellulose are deposited between the particles of the old wall. This process is known as intussusception. The another theory says that new cell wall particles are deposited on the inner surface of the old wall by the process known as apposition. Maximum elongation occurs in conducting tissue and fibres. Maturation phase : During this phase, the cells start maturing and differentiating to obtain a permanent shape and size such as fibres, tracheids, vessels, sieve tubes, cork cells, collenchyma, sclereids etc. The time interval from the formative phase to maturation phase is called the grand period of growth.

GROWTH RATES 

Growth rate refers to increase in growth per unit time.



Growth rate shows two types of increases i.e., arithmetic and geometrical.

Arithmetic growth •

•

In this type of growth, the rate of growth is constant and increase in growth occurs in arithmetic progression. After mitosis, only one daughter cell continues to divide while the other takes part in differentiation and maturation, e.g., root elongation at constant rate. Mathematically, it is expressed as Lt = L0 + rt where, Lt = length at time ‘t’; L0 = length at time ‘zero’; r = growth rate; t = time of growth. On plotting the growth against time, a linear curve is obtained.

Fig.15.3 Constant linear growth, a plot of length L against time t.

Geometrical growth •

In this type of growth every cell divides. Number of cells are initially small so that initial growth is slow. Later on, there is rapid growth at exponential rate. It is called log or exponential growth.

•

Plotting the growth against time will give a typical sigmoid or S-curve.

•

A sigmoid curve is a characteristic of living organism growing in natural environment. It is typical for all cells, tissues and organ of a plant.

• (i)

It has three phases : Lag phase : In this phase the rate of growth is slow. More time is needed for less growth.

PLANT GROWTH AND DEVELOPMENT

621

(ii) Log (or Exponential) phase : The growth rate becomes more and more rapid. The rate of growth reaches its maximum value. (iii) Stationary phase (or Steady state) : When the nutrients become limiting, growth slows down. This phase is indicated by the maturity of growth system. Mathematically exponential growth is expressed as W1 =W W0 ert where, W1 = final size (weight, height, number etc.) W0 = initial size at the beginning of the period e = base of natural logarithms r = growth rate t = time of growth Here, r is relative growth rate and is also the measure of the ability of the plant to produce new plant material, referred to as efficiency index. Hence, the final size of W1 depends on the initial Fig.15.4 An idealised sigmoid growth curve typical of cells in culture, size,W W0. and many higher plants and plant Quantitative comparisons between growth of living system can be done by following organs. methods: (i) Absolute growth rate : Measurement and comparisons of total growth per unit time is called the absolute growth rate. (ii) Relative growth rate : The growth of the given system per unit time is expressed on a common basis e.g., per unit initial parameter called the relative growth rate. Two leaves (A and B) have grown by 5 cm2 in one day. Initial size of leaf A was 10 cm2 while that of leaf B was 15 cm2, though their absolute growth is the same, relative rate of growth is faster in leaf A because of initial small size (Refer Fig. 15.5). B1

Check Point

A1

1. 2

10 cm

55 cm 2 2. 3.

50 cm 2

5 cm 2

B 4.

A

Fig. 15.5 Diagrammatic comparison of absolute and relative growth rates. Both leaves A and B have increased their area by 5 cm2 in a given time to produce A1, B1 leaves.

Which growth (arithmetic or geometrical) shows sigmoid or S-shaped growth curve? In which phase, rate of growth becomes more & more rapid? The measurement & the comparison of total growth per unit time is called__________. Two leaves P and Q of different sizes of area, shows exact absolute increase in the area in a given time. (True or False)

Conditions for Growth  





The proper growth of plant is influenced by supply of nutrients, water, oxygen, suitable temperature and light. Supply of nutrients : These inorganic nutrients are required for the synthesis of nitrogenous components for increased synthesis of protoplasm and carbohydrates as a source of energy. The ratio of carbohydrates & nitrogenous compounds regulates the specific pattern of growth in plants. In presence of more nitrogenous compounds than carbohydrates the production of protoplasm is more, vegetative growth is vigorous and shoot is large in comparison to root. When carbohydrates are more than nitrogenous compounds there is less synthesis of protoplasm & more of mechanical tissue. Temperature : The growth of plants increase with increase in temperature to the optimum range (28° to 30°C) after which the growth declines because protoplasm coagulates above 45°C temperature. Light : Light is not essential during the initial stages of the growth, but is required for further growth. Light controls many physiological processes like photosynthesis, transpiration, tissue differentiation, pigment formation, seed germination etc. There is a stimulating effect of light on plant growth. Growth generally favoured by darkness, neverthless, light is indespensible because of its role in manufacture of food.

Connecting Concepts  If temperature is low in night so as to reduce respiration and high in daytime so as to increase photosynthesis, there will be a high gain of photosynthetic product, which will result in increased rate of growth. This is why tubers of potato and other vegetables and fruits growing on hills are much larger than those of plains.

622

BIOLOGY



Some seeds (called photoblastic seeds) germinate only in presence of light, e.g., Viscum alba. Seeds of lettuce and tobacco require red light of 660 nm for their germination. Growth in absence of light results in etiolation (i.e., plants grow in length but have thin stems with narrow leaves and poorly developed root system). Water : It maintains the turgidity of growing cells and provides medium for enzymatic reactions.



Oxygen : It is required for respiration and release of energy, thus indispensable for growth.



Gravity : Vector of gravity determines the direction of shoot and root growth. Direction of light also determines the orientation of leafy shoots.



Other factors : Excess of salts, mineral deficiency & other stress factors have a detrimental effects on growth.

DIFFERENTIATION, DE-DIFFERENTIATION AND RE-DIFFERENTIATION Differentiation 

Differentiation is maturation of cells derived from apical meristems of root and shoot.



Differentiation is applied to the qualitative differences between cells, tissues and organs.



During differentiation cell undergo few to major anatomical and physiological changes both in their cell walls and protoplasm. For example, vegetative bud is transformed into flowering bud or a cambial cell differentiates to produce xylem or phloem cell. Also, in the formation of tracheary element the cells loose their protoplasm. They also develop a very strong, elastic lignocellulosic secondary cell wall to carry water to long distances even under extreme tension.

Check Point Fill in the blanks (i) Two examples of plasticity are _______ and _______. (ii) When _______ are more than _______ there is less synthesis of protoplasm and more of mechanical tissue. (iii) Growth in absence of light results in _______.

De-differentiation 

The living differentiated cells loose their capacity of division. These cells may regain their capacity to divide under certain conditions. This phenomenon is called as de-differentiation.



Such de-differentiated tissues can act as meristem, for example, interfascicular vascular cambium and cork cambium.

Re-differentiation 

The products of de-differentiated cells which lose the capability to divide but mature to perform specific functions are called re-differentiated cells. Secondary xylem and secondary phloem form inter fascicular vascular cambium, secondary cortex & cork are the examples of re-differentiated tissues.



The growth and differentiation in plant is open, i.e., it can be indeterminate or determinate. The final structure at maturity of a cell is determined by location of cell, e.g., cells positioned away from root apical meristem differentiated as root-cap while those pushed to periphery mature as epidermis.

DEVELOPMENT 

Development is a term that includes all changes that an organisms goes through during its life cycle from germination by the seeds to senescence.



In different phases of growth, plants follow different pathways and form different kinds of structures in response to environment. The ability to change under the influence of internal or external stimuli is called plasticity, e.g., heterophylly in cotton, coriander and larkspur. Occurrence of different types of structures on same plant in different growth phases or under different environmental conditions is known as heterophylly. On the other hand, difference in shapes of leaves produced in air and those produced in water in buttercup also represent the heterophyllous development due to environment.



Thus, Growth, differentiation and development are closely related events in the life of a

PLANT GROWTH AND DEVELOPMENT

623

plant. Development includes both growth and differentiation. There are two factors i.e., intrinsic and extrinsic, that controls the development in plants. Intrinsic factors includes both intracellular (genetic) and intercellular (growth regulators) factors. Extrinsic factors includes nutrition, light, temperature, water, oxygen etc.

Meristematic cell ↓

Cell Division ↓

Table 15.1 : Difference between Growth and Development Growth 1. It is irreversible and permanent increase in size or shape or mass accompanied by an increase of dry weight of an organism. 2. It is a process of cell division & enlargement accompanied by an increase in weight.

Plasmatic Growth ↓

Development It is an integrated & complex metabolic activities which include increase in volume and differentiation in form and structure.

Differentiation ↓

Cell Elongation ↓

Cell Maturation

It can be estimated by qualitative change of the body parts.

↓

Mature cell ↓

Senescence

PLANT GROWTH REGULATORS 

  

Growth and most of the physiological activities in plants are regulated by the action and interaction of some chemical substances present in them. These substances are called plant hormones or phytohormones. Plant hormone is a chemical substance which may be translocated to another region, for regulating one or more physiological reactions when present in low concentration. All phytohormones are growth regulators but all growth regulators are not phytohormones. Plant growth regulators are grouped into two categories based on the nature of their actions :

↓

Cell death.

Flow chart : 15.2 Germination of seeds to its senescence

(i) •

Plant growth promoters, e.g. auxins, cytokinins, gibberellins. They promote growth activities like cell division, cell enlargement, flowering, fruiting Juvenile and seed formation, etc.

(ii) •

Plant growth inhibitors, e.g., abscisic acid (ABA) and ethylene. They play an important role in plant response to wounds and stresses of biotic and abiotic origin.

•

They are involved in growth inhibiting activities such as dormancy and abscission.

Discovery of Plant Growth Regulators

Adult

Terrestrial habitat (a)

AUXIN 

Auxin was the first plant hormone to be discovered. Charles Darwin and his son Francis Darwin observed that the coleoptiles of Oat ((Avena sativa) and canary grass ((Phalaris canariensis) responded to unilateral illumination by growing towards the light source (phototropic curvature or phototropism).



After a series of experiments, it was concluded that the tip of the coleoptile was the site of production of a substance, that caused the bending of coleoptile.



F.W. Went isolated auxin from the tips of coleoptiles of oat ((Avena sativa) seedlings.



Auxin was first isolated from human urine. Kogl and Haagen smith (1931) isolaled 3 chemicals from human urine. They were named as auxin-a, auxin-b and heteroauxin. Kogl et-al (1934) found that heteroauxin is the real plant auxin and is chemically indole 3-acetic acid or IAA.



Auxin compounds produced by the growing apices of the stems and roots, from where they migrate to the regions of their action. Auxin transport is basipetal in stem & acropetal in roots.

Water habitat (b) Fig. 15.6 Heterophylly in (a) larkspur, and (b) buttercup

624

BIOLOGY 

Auxins like indole-3-acetic acid (IAA) and indole 3-butyric acid (IBA) have been isolated from plants. They are naturally occurring plant hormones.



Naphthalene acetic acid (NAA) and 2, 4-dichlorophenoxy acetic acid (2, 4-D) are synthetic auxins.



F. Skoog had reported that auxin is inactivated under the influence of X-rays & gamma radiations & ultraviolet light brings about inactivation of 1AA.



Avena curvature test (given by F.W. Went) & split pea stem curvature test are the bioassays that are generally used for auxins. Avena coleoptile curvature test (Bioassay) It involves extraction of auxins from the coleoptile tip in an agar block by placing the cut tip on the latter. The auxin containing agar block is now placed on one side of the decapitated stump of the coleoptile. An agar block without auxin is placed on another decapitated coleoptile with auxin agar block bends on to the side opposite to which agar block is placed. However no curvature is observed in the control coleoptile. The curvature occurs due to rapid growth of the side of the coleoptile on which agar block is placed. This curvature can be measured by exposing the curved coleoptile to a photographic plate. The amount of auxin in the agar block is directly proportional to the degree of curvatures.

Tip of the seedling removed and placed on agar

Ordinary agar block Auxin-agar block

Agar blocks Seedling A

B

C

Auxin caused growth on one side causing coleoptile to bend E F D

No curvature G

Fig. 15.7 Bioassay of auxin A : Avena coleptile B : Cut tip of the coleoptile is placed on agar block. C : Auxin-agar block is placed on the decapitated tip. D-E : Curvature of the coleoptile takes place on the side opposite to which agar block is placed. F-G : Control set showing decapitated coleoptile with ordinary agar block (note that no curvature takes place).

Gibberellin 

Gibberellin are named after fungus Gibberella fujikuroi which produces foolish seedling disease of rice or Bakanae disease by a Japanese plant pathologist E. Kurosawa (1926). He reported the symptoms of the disease in infected rice seedlings by treating them with filtrates of the fungus.

PLANT GROWTH AND DEVELOPMENT 

The active substances were later identified as the gibberellic acid.



Yabuta, Hayashi & Kahnbe first isolated the activated principle toxin secreted by the fungus which was called Gibberellin by them.



There are more than hundred gibberellins reported from various higher plants and fungi They are denoted as GA1, GA2, GA3 and so on. All GAs are acidic.



GA3 was the first gibberellin to be discovered and remains the most intensively studied form of GAs.



Gibberellins are present in parts of higher plants including shoots, roots, leaves, flower, anther & seeds. Reproductive parts contain more or higher concentration of gibberellins than the vegetative part.



Gibberellins are synthesized from a precursor compound mevalonic acid (derived from acetyl CoA).



Techniques used for the bioassay of gibberellins are dwarf pea elongation technique, barley endosperm digestion technique and dwarf corn test.



Compounds that inhibits the action of gibberellin are antigibberellins or gibberellins retardants, e.g. Phosphon D, Amo1618, Cycocel (CCC) etc.

Cytokinin 

F. Skoog and his co-workers observed that from the internodal segments of tobacco stem, the callus (a mass of undifferentiated cells) proliferated only if, in addition to auxins the nutrients medium was supplemented with one of the following : extracts of vascular tissues, yeast extract, coconut milk or DNA.



Skoog and Miller later identified and crystallized the cytokinesis-promoting substance and called it kinetin.



Cytokinins were discovered as kinetin (a modified form of adenine, a purine) from the autoclaved herring sperm DNA.



Kinetin does not occur naturally in plants. Search for natural substances with cytokininlike activities led to the isolation of zeatin from corn-kernels and coconut milk.



Later several naturally-occurring cytokinins and synthetic compounds with cell division promoting activity have been identified.



Natural cytokinins are synthesized in plants in regions where rapid cell division occurs; e.g. root apices, developing shoot buds, young fruits, etc.



Some of the bioassays for cytokinins are – •

Excised radish cotyledon enlargement test.

•

Chlorophyll preservation test or delay in senescence test.

•

Tobacco pith culture.

Ethylene 

Ethylene is a naturally occurring volatile hormone. A Russian Physiologists Dimitry N. Neljubow (1876 – 1926) first established that the ethylene affects plant growth.



Denny (in 1924) observed that ethylene is highly effective in inducing fruit ripening. Burg (1962) established that ethylene is the only gaseous growth regulator. Ethylene is a natural product of metabolism in plants. It is synthesized in plants from amino acid methionine.



Ripened oranges released a volatile substance that hastened the ripening of the stored bananas; later this volatile substance was identified as ethylene, a gaseous PGR. Crocker (1930) reported presence of ethylene from plant organ and named it as gaseous hormone.



Ethylene is synthesized in large amounts by the tissues undergoing ripening fruits and senescence.



Bioassays for ethylene are – triple pea test & pea stem swelling test.

625

Check Point 1.

Which plant hormone is determined by Avena curvature test? 2. NAA is a synthetic or natural hormone ? 3. Fill in the blanks. (i) The first auxin was isolated from _______. (ii) The auxin shows _______ movement in shoot & _______ movement in root. (iii) The most common naturally occurring cytokinin is ______ isolated from unripe maize grains. (iv) _______ is the only gaseous growth hormone. (v) Carns & Addicott extracted two substances – _______ from old cotton balls and _______ from young cotton balls.

626

BIOLOGY Abscisic Acid 

ABA was first identified and chemically characterized by Frederick T Addicott & his co-workers (Carns) in 1963 from young cotton fruits and named as abscission-I and another more active compound as Abscission-II. Abscission-II was named as Abscisic acid (ABA)



Robinson and Warming 1964, extracted the substance that is responsible for dormancy in Acer. They named this substance as dormin. Later it was found that Abscission-II and dormin were identical compound for which Addicott suggested the name abscisic acid. ABA is general inhibitor of growth and metabolism.



Abscisic acid (ABA) is a naturally occurring growth regulator that is found in all vascular plants and some mosses. It is absent in bacteria, algae, most of fungi and liverworts. Lunaric acid, an analogue of ABA is reported to be present in algae and some liverworts.



Site of synthesis of abscisic acid is many parts of the plant but more inside the chloroplasts of green cells.



Bioassays for abscisic acid are rice seedling growth inhibition test & inhibition of amylase synthesis in barley endosperm.

Physiological Effects of Plant Growth Regulators AUXIN 

There are several physiological effects of auxin in plants. The major functions of auxin are as follows.



Cell enlargement : Auxin promotes elongation and growth of stems and roots & enlargement of many fruits by stimulating cell enlargement. Auxin causes softening of cell wall, loosening of cell wall microfibrils & increases the membrane permeability as well as endosmosis. Auxin stimulation

Increase in cell membrane permeability

More salt entry

Stretching of cell wall resulting in cell enlargement

Endosmosis i.e. entry of water

Increase in osmotic pressure

Flow chart 15.3 : Sequential steps in the cell enlargement due to auxin stimulation

Connecting Concepts



Cell division in cambium – Auxin has been found to be responsible for initiating and promoting cell division in certain tissue such as cambium. The reactivation of the cambium in the growing season is apparently triggered by IAA moving from the developing shoot buds. The degree of cambial activity is directly proportional to the auxin concentration.



Flower initiation – Auxin generally inhibits flowering but in case of pineapple and litchi, foliar spray of dilute solution of auxins (2, 4-D, NAA) induces early flowering. In pineapple, flowering and fruiting is so much erratic that the pickers have to visit the field again and again to collect fruits as they ripen. After spraying of auxins the whole crop flowers with amazing uniformity. Auxin, like IAA have a feminising effect (formation of female flowers) on some plants.



Apical dominance –The phenomenon of apical dominance can be seen in most of the vascular plants in which, in the presence of apical bud, growth of lateral buds (formed just below the apex) is suppressed. At the removal of apical bud, the lateral buds grow vigorously. It shows that apical bud suppresses the growth of lateral bud (axillary bud) just below it. This is known as apical dominance. It is widely used in tea plantation & hedge making.

 Hitchock & Zimmerman for the first time showed that flowering in Nicotiana can be stimulated by auxin.

Apical dominance is due to presence of high concentration of auxins in apical buds.

PLANT GROWTH AND DEVELOPMENT

(a)

627

(b)

Fig. 15.8 Apical dominance in plants : (a) A plant with apical bud intact, (b) A plant with apical bud removed Note the growth of lateral buds into branches after decapitation













 

Control of abscission : The he formation of aabscission layer often results in the premature fall of leaves, flower and fruit. Auxin controls the preharvest drop of fruit such as apple, pear and citrus by retardation of abscission i.e., by delaying the formation of separation layer at the base of petiole. Parthenocarpy : Auxin induces the formation of parthenocarpic fruits. Parthenocarpy refers to development of seedless fruit that occurs without pollination and fertilization. (After pollination and fertilization the ovule is converted into seed and ovary into fruit). It has been observed that the carpels producing parthenocarpic or seedless fruits (e.g. banana, grapes etc.) have a higher internal production of auxins. Prevention of lodging : Lodging (i.e., fall down due to an excessive elongation and softening of the cells in the basal internodes) of some crop plants like oats and flex is prevented by the treatment of naphthalene acetamide (NAAM) that makes the plant stiff, woody and erect. NAAM initiates cell division in the cambium and hence increases the amount of xylem to strengthen the basal part of stems. Weed control : Weeds are unwanted plant growing in the field along with the crop. Auxin is used as weed killers because of following reasons: • They are selective herbicidal in action. • Toxic residues of auxins disappear quickly from the soil. • Auxins are effective in very low concentration. • They are not harmful to human beings and animals. • It is used to prepare weed-free lawns by gardeners.

Plant tissue differentiation – Plant tissue can form shoots, roots or an undifferentiated mass of tissues depending upon the relative amounts of auxin & cytokinin. High auxin to cytokinin ratio favour the root development in tissue culture whereas high cytokinin to auxin ratio favour shoot development. The intermediate concentration results in the formation of undifferentiated cells. Shortening of internodes : In apple and pear, there are two types of branches. The fruits are borne by dwarf ‘spurs’. If the terminal shoots are treated with high concentration of NAA, their elongation is prevented and they become dwarf shoots. These dwarf shoots can also bear fruits. Few auxins are used in prolonging the life of storage products like corm, tuber, rhizomes etc, e.g., NAAM. According to Cholodny-Went theory auxins are responsible for phototrophism & geotropism.

Gibberellin 

Connecting Concepts

 Agent orange – Mixture of two phenoxy herbicides in ester form, 2, 4, D & 2, 4, 5 -T (dioxin) is given the name agent orange, which was used by USA in Vietnam war for defoliation of forests (i.e., in chemical warfare). Phenoxy agents work by mimicking a plant They are widely used as weedicides or herbicides. 2, 4-D, widely used to kill dicotyledonous growth hormone, IAA. When sprayed weeds, does not affect mature monocotyledonous plants. 2, 4-D is a selective weed killer on broad leaf plants they induce rapid as it is toxic to broad leaved plants & in low concentration it is useful in preventing uncontrolled growth eventually killing preharvest fruit drop of orange and apple. them.

Stem elongation –The most typical and striking effect of gibberellin is on the elongation of stem. The internodes increase in length. The elongation effect is enhanced if auxin is also present.

628

BIOLOGY

Connecting Concepts



Seed germination – Some light sensitive seeds [e.g., Lactuca sativa (Lettuce), barely etc] can germinate in complete darkness when treated with gibberellin.



During seed germination, especially of cereals, gibberellins stimulate the production of some messenger RNA and then hydrolytic enzymes such as proteases, amylases, lipases. These enzymes solubilise the reserve food of the seed & thus help to mobilise the same to the embryo for its growth.



Breaking dormancy – Gibberellins takes part in breaking of natural dormancy of seeds, buds & underground plant parts. In this function gibberellin acts antagonistically to abscisic acid (ABA).



Bolting & flowering –Gibberellin causes the plants (like beet, cabbage, etc) to bolt and flower. In many plants, in first year of growth internode remains short and leaves are developed in the form of rosette where a large number of broad leaves remain attached to a very short axis. Just before reproduction internodes grow strikingly and starts flowering. This phenomenon is known as bolting. Usually such plants require specific long day photoperiods or cold requirements to bolt and flower.



Delayed senescence – Ripening of Citrus and apple fruits can be delayed with the help of gibberellins. The fruits can be left on the tree longer to extend market period. It is also useful for safe and prolonged storage of fruits.



Parthenocarpy – Gibberellins have been found to be more effective than auxins in causing parthenocarpic development of fruits, e.g., tomatos, apples and pears.



They cause fruits like apple to elongate and improve its shape.



Gibberellins are used to increase the length of grape stalks.



By increasing the length of internodes in sugarcane, GA3 increases the yield of sugarcane by about 20 tonnes/acre.



Spraying juvenile conifers with GAs hastens their maturity and leads to early seed production.

 Synthesis of florigen (which is  a flowering hormone) is mediated  through gibberellins.  A combination of cytokinin (6-benzyl-adenine) & gibberellins (GA4GA7) called pomalin is particularly  effective in increasing apple size.

Malting process – GA3 is employed to speed up malting process in brewing industry.

Elongation of genetically dwarf plants – Genetic dwarfism is caused by mutation of a single gene. If gibberellin is sprayed on these single gene dwarf plants, genetic dwarfism is overcome & plants become long, e.g. in maiza, pea etc. Gibberellin plays an important role in the initiation of flowering in vernalised & long day plants during short day condition, e.g., cabbage.

Cytokinin 

Cell division and Cell enlargement : Cytokinins are true cell division factors. Permanent cell division occurs only in presence of cytokinins. It also plays important role in causing expansion of cells.



Morphogenesis : Cytokinins play a part in intiation of organ formation in variety of tissue cultures. It opposes initiation of roots in stem cuttings treated with auxin and results in the formation of callus at the cut end. In tissue culture, cells of tobacco pith forms callus if supplied with nutrients and sugars. Skoog and Miller (1957) found that •

In a balanced medium of auxin and cytokinins pith grew as an amorphous, undifferentiated callus.

•

A relative increase in cytokinins level in medium caused the formation of buds which might grow into shoots. Though cytokinins are produced by roots, the formation of root in this case is probably inhibited due to supra-optimal levels of cytokinins.

•

A relative decrease of cytokinins causes pith culture to form roots.

•

Intermediate cytokinin/ auxin ratio causes formation of roots as well as shoots.

•

Intermediate cytokinins/low auxin causes growth of large amount of callus.

•

These methods are very useful in genetic engineering where new crop plants can be developed with the use of cultured cells. In addition to root and shoot differentiation other morphogenic responses include formation of plastids, differentiation of tracheids, induction of flowering and parthenocarpy.

PLANT GROWTH AND DEVELOPMENT 





 

629

Reduces apical dominance : When cytokinin is applied externally, the lateral bud grows even in presence of apical bud. Thus, cytokinins reverse the auxin induced inhibition of lateral buds and counteract the apical dominance. Delay in senescence (Richmond-Lang effect) : Richmond and Lang (1957) reported the delay of senescence (chlorophyll disappearance and protein degradation) for several days in the detached leaves of Xanthium X when they were treated with kinetin by controlling protein synthesis and mobilisation of resources. The phenomenon of delaying ageing due to cytokinin is known as Richmond-Lang effect. Breaking of dormancy : Cytokinins not only breaks dormancy but also promotes the germination of seeds. The cytokinins substitute the light requirement for breaking the dormancy of seed. Cytokinins also reverse the effect of certain naturally occurring inhibitors of seed germination as coumarin and xanthatin. They also promote adventitious shoot formation as they help to produce new leaves & chloroplasts in leaves. Cytokinin induce flowering in short day plants like Lemna, Wolffia.

Ethylene  



      

Triple response : Chadwick and Burg (1967) proposed that ethylene inhibits elongation of stem, causes swelling of nodes and nullifies geotropism. Inhibitory effect on growth : Ethylene inhibits the stem elongation; it is associated with radial enlargement of tissues that results in swelling of plant parts. Application of overdoses of auxin induces the ethylene formation. Fruit ripening : Ethylene is highly effective in inducing fruit ripening when it is produced in large amount which coincides with respiratory climacteric i.e., a brief rise to a very high level of respiration. This rise indicates the beginning of senescence and death. Ethylene increases the permeability of cell because of which the fruit is softened and entry of oxygen into fruit is accelerated. Climacteric can be prevented by eliminating oxygen from the atmosphere to prevent respiration. It hastens the senescence of leaves and flowers. Abscission of various parts (leaves, flowers, fruits) is stimulated by ethylene. It breaks the dormancy of buds, seeds and storage organs. Ethylene promotes root initiation, growth of lateral roots and root hair. This increases the absorption surface of the plant roots. It stimulates flowering in pineapple and related plants as well as in mango. Ethylene has a feminising effect on sex expression. e.g., in cucumber, Cannabis etc. Ethephon is the compound used to supply ethylene. It is readily absorbed in aqueous solution and transported within the plant and it releases ethylene slowly. Ethephon hastens fruit ripening in tomatoes and apples. It accelerates abscission of flowers and fruits in cotton, cherry, walnut, etc.

Abscisic Acid (ABA) 

 

Abscisic acid is a mildly acidic growth hormone which functions as a general growth inhibitor by counteracting other hormones (like, auxin, cytokinins, gibberellins) or reactions mediated by them. The synthesis of abscisic acid is stimulated by drought, water logging & other adverse environmental conditions. Therefore it is also called as stress hormone. Physiological effect of abscisic acid are as follows— • Growth inhibitor : ABA inhibits seed germination and growth of excised embryos, inhibits growth in duckweeds. • Abscission of leaves, fruits and flowers : Spray of abscisic acid causes abscission of leaves, fruits and flower. • Bud and seed dormancy : ABA induces dormancy in various plants. In duckweed plants ABA accumulation results in winter bud dormancy. Because of its action in inducing dormancy, ABA is also called dormin. The bud as well as seeds sprouts only when ABA is overcome by gibberellins. ABA is called antigibberellin.

Connecting Concepts  Term Climacteric was given by Kidd & Wont (1930). Examples of climacteric fruits are – apple, banana, mango, pear, peach, plum, tomato & non climacteric fruits are citrus, grape, pineapple, strawberry, watermelon, cherry etc.

Check Point 1.

Match the column-I with column-II. Column-I

1.

Auxin

2.

Cytokinin

3.

Gibberellin

4.

Ethylene

5.

ABA

Column-II (a) Stimulation of enzyme production of germinating seeds. (b) Initiation and promotion of cell division in cambial tissues. (c) Inhibits apical dominance. (d) Also called stress hormone. (e) Promotion of fruit ripening.

630

BIOLOGY •

Stomatal closing : ABA accumulates in high concentration in leaves which are wilting. This increased production of ABA stimulates stomatal closure by inhibiting the K+ uptake by guard cell and promoting the leakage of malic acid and hence prevents transpirations.

•

Water stresses : ABA increases tolerance of plants to various kinds of stresses.

•

Seed development : Abscisic plays major role in seed development and maturation, enabling seeds to withstand desiccation and to become dormant. Table 15.2 : A brief account of plant hormones, their function & location.

Hormone Auxin (IAA)

Cytokinin

Functions – – – – – – – – – – –

Check Point State True or False. (i) 2, 4D is used as weedicide to remove broad leaved weeds. (ii) Apical dominance is under control of gibberellin. (iii) Auxin inhibits abscission of leaves & fruits. (iv) Ethylene stimulates transverse expansion in stems. (v) Cytokinin is responsible for Richmond lang effect.

Gibberellins

– – Ethylene – (Only gaseous – hormone) –

Abscisic acid (ABA)

Connecting Concepts  Phytochrome and florigen : The chemical which perceives the photoperiodic stimulus in leaves is called phytochrome and after perceiving the required favourable photoperiod, leaves produce a chemical which stabilises in dark. It is then passes over to the shoot apex which undergoes differentiation to produce flower. The hormone which induces flower formation is named as florigen by Chailakhyan in (1930). Florigen is produced only when the plants have completed juvenile stage.

– – –

– – – – –

Promotion of stem elongation & growth. Apical dominance. Formation of adventitious roots. Inhibition of leaf abscission. Promotion of cell division (with cytokinin). Inducement of ethylene production. Promotion of lateral bud dormancy. Phototropic and gravitropic response. Stimulation of cell division but only in presence of auxin. Delay in senescence (leaf ageing). Promotion of chloroplast development & bud formation. Breaking dormancy & seed germination. Promotion of stem elongation. Stimulation of enzyme production in germinating seeds. Stimulation of bolting & flowering in biennials. Fruit development & parthenocarpy. Sex expression in Cucurbits. Control of leaf, flower & fruit abscission. Promotion of fruit ripening. Inhibits growth of lateral buds.

Inhibition of bud growth Control of stomatal closure. Some control of seed dormancy. Inhibition of effects of other hormones. Helps in dormancy in seeds and buds

Location Apical meristem, embryo of seed, young leaves.

Root apical meristem, immature fruits.

Roots & shoot tips, young leaves & seeds.

Roots, shoot apical meristem, leaf nodes, ageing flower, ripening fruits Leaves, fruits, roots caps, seeds

PHOTOPERIODISM 

The effect of photoperiods or daily duration of light hours (and dark periods) on the growth and development of plants, especially flowering, is called photoperiodism. Thus, the response of plants to periods of day/night is called as photoperiodism.



It was first studied by W. W. Garner & H. A Allard (1920) in ‘Maryland Mammoth’ (mutant variety and tobacco).



They found that Maryland Mammoth, flowered at different times at different places (latitudes). They observed that it is variation in day length that plays a decisive role in controlling flowering in these plants. The site of perception of light/dark duration are leaves.



Critical photoperiod is that continuous light duration which must not be exceed in long day plants in order to bring them flowering.

PLANT GROWTH AND DEVELOPMENT

631

Types of Plants on the Basis of Photoperiods 

The plants are classified into three groups according to their photoperiods viz., long-day plants, short-day plants and day-neutral plants.

Long Day Plants (LDPs)    

These are the plants which require exposure to light for a period exceeding a well-defined critical light period (varies from 4 to over 18 hours), to initiate flowering. In long day plants, periods of darkness have an inhibitory effect on the flowering of the plants. Thus, long day plants are also called as ‘short night plants’. Long day plants can flower under short day conditions, if a flash of light is given to the plants during the long dark period. The long day plants are wheat, barley, sugar beat, larkspur, radish etc.

Short Day Plants (SDPs) 

  

These are the plants which require exposure to light period much shorter than the critical light period; actually they require long uninterrupted dark period. The length of night is more important than the length of day. Thus, short day plants are also called as ‘long night plants’. Several short day plants flower in continuous darkness, if they are given sucrose suggesting that light is needed only for photosynthesis. Flowering is inhibited if a very weak intensity of light is given to the plant. Most of the plants are short day plants that include tobacco Cosmos, Dahlia, Chrysanthemum, rice, etc. and are generally grown in the winter season.

Intermediate or Day Neutral Plants 



The remaining plants come under the class of neutral or intermediate day plants. These plants do not require specific photoperiods to flower. Such plants flower in almost all the photoperiods ranging from few hours to 24 hours of uninterrupted light periods. Cucumber, sunflower, tobacco, tomato etc. are some examples of intermediate day plants.

Above

No flowering

Critical photoperiod

Above

Flowering

Below

Critical photoperiod Below

Flowering

No flowering

Flowering after vegetative maturity

Short-day plant

Long-day plant

Day neutral plant

Fig. 15.9 Three major types of photoperiodic behaviour for flowering

Mechanism of Photoperiodism 

Phenomenon of producing photoperiod influence on the production of flower is called photoperiodic induction or photoinduction. Photoperiodic induction generally occurs when plant has achieved certain minimum vegetative growth which in turn provides the plants with ripeness to flower.

632

BIOLOGY 

The stimulus received by the actively dividing cells of shoot or embryo tip travels to all parts of the plants and prepare it to flowering. Leaf is the site of perception of light of photoperiodism.



It has been hypothesized that there is a hormonal substance(s) that is responsible for flowering. This hormonal substance migrates from leaves to shoot apices for inducing flowering only when the plants are exposed to the necessary inductive photoperiod.

Importance of Photoperiodism 

It determines the season, in which a particular plant shall come to flower. E.g., SDP flowers in autumn spring period & LDP flowers in summer.



It is useful in keeping some plants in vegetative growth to obtain higher yield of tubers, rhizomes etc. or keep the plant in reproductive stage to bear more flowers and fruits.



It helps plant breeders in effecting cross breeding in plants which normally develops flowers in different seasons.



This phenomenon is also useful in laying out gardens, orchards & planting crop patterns of the area.

VERNALIZATION Connecting Concepts



 Klippert (1857) first noticed the low temperature requirement for flowering  in two varieties of wheat i.e., winter & spring. German plant physiologist  George Melchers (1937) has proposed the existence of a stimulus of  vernalization & coined it vernalin.

Check Point 1.

Match the column-I with column-II. Column-I

Column-II

1.

Photoperiodism

2.

Vernalization

3.

Senescence

4.

Phytochrome

(a) Perceives photoperiodic stimulus in leaves. (b) Sum of deteriorative processes. (c) Low temperature treatment of seeds. (d) Effect of light/ dark duration on growth & development of plant.

2. 3.

4.

Give 2 examples of short day plants & long day plants. In short day plant flowering is induced by _________ (MCQ). (a) long night. (b) photoperiods less than 12 hours. (c) photoperiods shorter than initial value and uninterrupted long night. (d) short photoperiods and uninterrupted long nights. The photoperiodic stimulus is perceived by _______.

Vernalization is a process in some plants where flowering is either quantitatively or qualitatively dependent on exposure to low temperature. It prevents precocious reproductive development late in growing season. It allows the plant to reach vegetative maturity before reproductive development. Chouard (1960) has defined vernalization as the “acquisition or acceleration of the ability to flower by a chilling treatment”. It has been observed that plants from temperate regions require a period of low temperature before flowering takes place. The application of temperature between 1 to 10°C to certain varieties of wheat, rice, millets and cotton, accelerates the growth of seedlings and results in early flowering.



The site for vernalization is meristematic cells in the bud, apex of embryo, developing leaves etc.



Work of Wellensick (1964) showed that all dividing cells including those in roots or leaves may be potential sites of vernalization.



Some important food plants, wheat, barley, rye have two kinds of varieties: winter and spring varieties. The ‘spring’ variety are planted in the spring and come to flower and produce grain before the end of the growing season. Winter varieties, however, if planted in spring would normally fail to flower or produce mature grain within a span of a flowering season. Hence, they are planted in autumn (september to october). They germinate, and over winter come out as small seedlings, resume growth in the spring and are harvested usually around mid-summer.



Vernalization is also seen in biennial plants. Biennials are monocarpic plants that normally flower and die in the second season. Sugarbeet, cabbages, carrots are some of the common biennials. Subjecting the growing of a biennial plants to a cold treatment stimulates a subsequent photoperiodic flowering response.



The vernalization effect is reversible and the process is termed as devernalization. If a vernalized seed or plant is kept at high temperature, the effect of low temperature treatment is completely removed. High temperature reversal can be counteracted if the duration of vernalization treatment is increased. Devernalized plants can be again vernalized by low temperature treatment.

Significance of vernalization are •

Vernalization shortens the vegetative period of the plant.

•

It increases the cold resistance of the plants.

•

Increases the resistance of the plants to fungal diseases.

PLANT GROWTH AND DEVELOPMENT

SEED DORMANCY 

Dormancy may be defined as the inactive state of the seed in which the growth of the embryo is temporarily suspended for a specific length of time.



Many viable seeds germinate immediately after harvest if provided with suitable conditions of germination, i.e., water, oxygen and suitable temperature (some seeds, e.g., lettuce need light also). However, perfectly viable seeds of many plants do not germinate immediately after harvest even when provided with suitable conditions of germination, i.e., their germination is blocked. This block to the process of germination is called dormancy.



The seed dormancy may be due to many causes, such as external environment, endogenous control or condition within seed itself. Some of which are as follows : •

Impermeability of seed coats to oxygen, e.g., Xanthium.

•

Impermeability of seed coats to water, e.g., many plants of legumes.

•

Hard seed coat, which does not allow proper growth of developing embryo, e.g., mustard.

•

Immature embryo: Some seeds contain an imperfectly developed embryo.

•

Embryo requiring after-ripening in dry storage: These embryos although developed fully, do not germinate unless kept in storage in a dry place for sometime after harvest.

•

Germination inhibitors : Some plants produce such chemical compounds that inhibit the germination of their own seeds, e.g., tomato. The pulp of the fruit produces an inhibitor.

•

Other chemical inhibitors are abscissic acid, phenolic acid, para-ascorbic acid, etc.

Methods of Breaking Dormancy 

Various methods have been employed for breaking dormancy of seeds. Some of which are as follows: •

Mechanical scarification: Weakening of hard seed coat with anything of sharp edge, e.g., pieces of glass, knives, sand paper or vigorous shaking.

•

In nature, these abrasions are caused by microbial action and passes through digestive tract of animals.

•

Chemical scarification : Treating the seeds with dilute acids, fat solvents, etc. Dormancy can be broken by treating the seeds with strong acids (N2SO4) or dipping in boiling water or rubbing on a rough surface. This is called chemical scarification.

•

Chilling treatment : Low temperature treatment, alternating low and high temperature treatment.

•

High temperature treatment : Permeability of seed coat in alfa-alfa seed increases when they are kept in water at the temp. of 85-90° for some time.

•

To neutralize the effect of inhibitors : Effect of germination inhibitors in the seeds can be counteracted by giving low and high temperature treatment to seeds or by treating the seeds with KNO3, thiourea, gibberellin, ethylene, chlorohydrin, etc.

633

634

BIOLOGY

EXERCISE - 1 | NCERT BASED QUESTIONS 1.

2.

3.

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6.

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8.

9.

10.

11.

The maximum growth rate occurs in (1) exponential phase (2) stationary phase (3) senescent phase (4) lag phase Phytohormones are (1) chemicals regulating flowering. (2) chemicals regulating secondary growth. (3) hormones regulating growth from seed to adulthood. (4) regulators synthesized by plants and influencing physiological processes. Highest auxin concentration occurs (1) in growing tips (2) in leaves (3) at base of plant organs (4) in xylem and phloem According to Cholodny Went theory, which phytohormone is responsible for phototropism and geotropism? (1) GA (2) Cytokinin (3) ABA (4) Auxin Movement of auxin is (1) centripetal (2) basipetal (3) acropetal (4) Both (2) and (3) Apical dominance means (1) suppression of growth of apical bud by axillary buds. (2) suppression of growth of axillary buds by the presence of apical bud. (3) stimulation of growth of axillary buds by removal of apical bud. (4) inhibition of growth of axillary buds by removal of apical bud. “Foolish seedling’’ disease of rice led to the discovery of (1) ABA (2) 2, 4-D (3) IAA (4) GA The regulator which retards ageing / senescence of plant parts is (1) GA (2) cytokinin (3) auxin (4) ABA Cut or excised leaves remain green for long if induced to root or dipped in (1) gibberellins (2) cytokinins (3) auxins (4) ethylene Ethylene gas is used for (1) growth of plants. (2) delaying fruit’s abscission. (3) ripening of fruits. (4) stopping the leaf abscission. Plant hormone associated with climacteric respiration is (1) auxin (2) cytokinin (3) ethylene (4) gibberellin

12.

In short day plants, flowering is induced by (1) photoperiod less than 12 hours. (2) photoperiod below a critical length and uninterrupted long night. (3) long night. (4) short photoperiod and interrupted long night. 13. The method that renders the seed coat permeable to water so that embryo expansion is not physically retarded is called (1) vernalization (2) stratification (3) denudation (4) scarification 14. In which of the following form of growth, new cells are always being added to the plant body by the meristematic activity ? (1) Close form of growth. (2) Open form of growth. (3) Diffused form of growth. (4) Discontinuous form of growth. 15. Identify the correct and incorrect statements from the following. (I) 17500 new cells are produced per hour by a single maize root apical meristem. (II) With the help of length, growth of pollen tube is measured. (III) The growth of the leaf is measured in term of volume. (IV) Cells in a watermelon may increase in size by upto 350000 times. (1) I, II, III are correct and IV is incorrect. (2) I, II, IV are correct and III is incorrect. (3) II, III are correct and I, IV are incorrect. (4) I, IV are correct and II, III are incorrect. Directions (16-17): In the following questions, more than one of the answers may be correct. Select the correct answer and mark it according to the code given below. (1) a, b, and c are correct. (2) a and b are correct. (3) b and d are correct. (4) a and c are correct. 16. Which of the following statement regarding gibberellin are correct ? a. GA3 is used to speed up the malting process in brewing industry. b. GA3 is a commercially available gibberellin. c. Spraying juvenile conifers with GAs hastens the maturity, thus leading to early seed production. d. GA3 cannot increase the length of internode of sugar cane. 17. Which of the following statements are false ? a. C2H4 breaks seed and bud dormancy. b. ABA stimulates the opening of stomata. c. Cytokinin is primarily concerned with cell division. d. ABA is synergistic to GA.

PLANT GROWTH AND DEVELOPMENT 18.

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Linear curve is obtained in arithmetic growth, because (1) it has lag, log and stationary phase. (2) one daughter cell remains meristematic while the other daughter cell differentiates and matures. (3) of the effect of environment on mitosis. (4) of the ability of the plant to produce new plant material. What will be the effect on phytochrome in a plant subjected to continuous red light? (1) Level of phytochrome decreases. (2) Phytochrome is destroyed. (3) Phytochrome synthesis increases. (4) Destruction and synthesis of phytochrome remain in equilibrium. The exponential growth can be expressed as W1 = W0ert. What is ‘r’ in the expression ? (1) Relative growth rate and depends on final size. (2) Absolute growth rate & depends on initial size. (3) Relative growth and also referred to as efficiency index. (4) None of the above Which of the following include all the three process ? (1) Differentiation (2) Cell enlargement (3) Seed germination, senescence (4) Development The ability of plant to follow different pathways and produce different structures in response to environment and phases of life is termed as (1) elasticity (2) growth efficiency (3) plasticity (4) heterophylly Intrinsic heterophylly is seen in all except (1) cotton (2) coriander (3) buttercup (4) larkspur Refer the functions of the growth hormones given below. I. Cell division II. Cell enlargement III. Pattern formation IV. Tropic growth V Flowering VI. Fruiting VII. Seed germination VIII.Response to wound IX. Response to stresses of biotic and abiotic origin Identify the functions of growth promoters and growth inhibitors from the above.

(1) (2) (3) (4) 25.

635

Functions of growth promoters I, II, VII, IX VIII, IX I, II, III, IV, V, VI, VII I, II, III, IV, V, VI, VII, IX

Functions of growth inhibitor III, IV, V, VI, VII I, II, III, IV, V, VI, VII VIII, IX VIII

Match the column A (Scientists) with column B (Discovery). Column-A

Column-B

I. II. III.

C. Darwin and F. Darwin Miller and Skoog F.W. Went

A. B. C.

Cytokinin ABA C2H4

IV.

Kurosawa

D. E.

Auxin GA

(1) (2) (3) (4) 26.

(2) (3) (4)

28.

29.

II A A A D

III C E B A

IV E B D C

Refer the statements given below. Statement-I : Confirmation of the release of volatile substance from ripened oranges that hastened the ripening of stored unripe bananas. Statement-II : Callus formation takes place from internodal segments of tobacco stem with the auxin and the nutrient medium containing extracts of vascular tissues/yeast/coconut milk/ DNA. Later, cytokinesis promoting substance was identified, crystallized and named as Kinetin. Statement-III : Reporting of appearance of symptoms of bakane/foolish seedling disease caused by fungus, Gibberella fujikuroi, in uninfected seedling when they were treated with sterile filtrates of the fungus. The active substances were later identified as GA. Choose the correct option. (1)

27.

I D D C E

I Miller + Skoog Kurosawa Cousins Cousins

II Cousins

III Kurosawa

Cousins Kurosawa Miller + Skoog

Miller + Skoog Miller + Skoog Kurosawa

Which process is not directly affected by auxin ? (1) Apical dominance and root initiation. (2) Parthenocarpy. (3) Synthesis of α-amylase by barley seeds. (4) Leaf abscission. Kinetin, a modified adenine (purine) was discovered from (1) the autoclaved herring sperm DNA (2) coconut milk (3) corn-Kernel (4) fungus Study the following statements. I. “X” hormone promotes root growth and root hair formation. II. “Y” hormone induces flowering in mango and also promotes rapid internode/petiole elongation in deep plants and hence helping leaves or upper parts of shoot above water. III. “Z” hormone inhibits the seed germination, increase the tolerance of plant to various stresses, play import in seed development, maturation and dormancy. Identify the correct names of hormones marked as ‘X’, ‘Y’ & ‘Z’. (1) Y = ABA; X = Auxin; Z = GA (2) Z = GA; X = Auxin; Y = C2H4 (3) Y = Auxin; X = C2H4; Z = GA (4) Y = C2H4; X = C2H4; Z = ABA

636 30.

BIOLOGY The picture below shows three different types of plants (marked as P-I, P-II and P-III) which flower on the basis of their critical photoperiod. Now identify these plants (P-I, II and III).

Above

32.

Refer the diagram which shows the stages of seed germination. Young leaves Cotyledons B C Soil line D

Above

A No flowering

Critical photoperiod

Identify A, B, C and D. Flowering

Critical photoperiod

Below

Below

Flowering

No flowering

Flowering after vegetative maturity

P-I

P-II

P-III

31.

(1) (2) (3) (4)

(1) P-I = Long day plant; P-II = Short day plant; P-III = Day neutral plant (2) P-I = Short day plant; P-II = Long day plant; P-III = Day neutral plant (3) P-I = Short day plant; P-II = Short day plant; P-III = Day neutral plant (4) P-I =Long day plant; P-II = Long day plant; P-III = Day neutral plant The picture below shows a graph drawn on the parameters of growth versus time. A, B, C respectively represent

33.

34.

A

Size

B

Time

A B (1) Exponential Log phase phase (2) Steady state Lag phase phase (3) Log phase Steady state phase (4) Log phase Lag phase

C Steady state phase Log phase 35. Logarithmic phase Steady state phase

B

C

Plumule Radicle Hypocotyl Root hair

Cotyledons Seed coat Cotyledons Cotyledons

Hypocotyl Epicotyl Epicotyl Plumule

D Epicotyl Hypocotyl Root hair Hypocotyl

Which of the following is the correct sequence of the developmental process in a plant cell ? (1) Plasmatic growth, Differentiation, Senescence and Maturation respectively. (2) Plasmatic growth, Differentiation, Maturation and Senescence respectively. (3) Maturation, Plasmatic growth, Differentiation and Senescence respectively. (4) Differentiation, Plasmatic growth, Maturation and Senescence respectively. Match the plant hormones listed in column-I with their major role listed in column-II. Select the correct option from the codes given below. (A) (B) (C) (D)

C

A

Column-A Auxin Cytokinins Abscisic acid Ethylene

Column-B (I) Fruit ripening (II) Phototropism (III) Antagonist to GAs (IV) Stomatal opening and closing (V) Growth of lateral buds

(1) A-IV; B-V; C-III; D-I (2) A-II; B-IV; C-III, IV; D-I (3) A-I; B-V; C-III, IV; D-I (4) A-III, IV; B-V; C-II; D-I Which of the following effects is brought about by gibberellins but not by auxins? (1) Inhibition of leaf abscission. (2) Stimulation of cambial activity. (3) Stimulation of fruit development. (4) Breaking of dormancy in leaf buds.

PLANT GROWTH AND DEVELOPMENT

637

EXERCISE - 2 | Window to Competitive Exams 1.

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A chemical believed to be involved in flowering is [CBSE PMT '91, '95] (1) gibberellin (2) kinetin (3) florigen (4) IBA Gibberellins promote [CBSE '88, '97] (1) seed germination (2) seed dormancy (3) leaf fall (4) root elongation What will be the effect on phytochrome in a plant subjected to continuous red light? [CBSE '97] (1) Level of phytochrome decreases (2) Phytochrome is destroyed (3) Phytochrome synthesis increases (4) Destruction and synthesis of phytochrome remain in equilibrium. Which of the following induces flowering in short day plants ? [AFMC '97] (1) Gibberellin (2) Cytokinin (3) Auxin (4) Ethylene Excessive elongation of plant stem is due to [BHU '97] (1) cytokinin (2) GA (3) ABA (4) IAA The response of different organisms to environmental rhythms of light and darkness is called [CBSE '98] (1) phototaxis (2) photoperiodism (3) phototropism (4) vernalization. Which is employed for artificial ripening of banana fruits? [CBSE '92, 2000] (1) Auxin (2) Coumarin (3) Ethylene (4) Cytokinin A plant completing its life cycle before the onset of dry condition is said to be [AFMC 2000] (1) short day plant (2) long day plant (3) drought escaping (4) all of these Which of the following cell is totipotent ? [AFMC 2000] (1) Meristem (2) Sieve tube (3) Cork (4) Xylem vessels The hormone which controls cell division and cell differentiation is [AFMC '98, 2000] (1) ABA (2) auxin (3) gibberellin (4) cytokinin Which of the following prevents fall of fruits? [CBSE '01] (1) GA3 (2) NAA (3) Ethylene (4) Zeatin

12.

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Which of the following hormone breaks bud dormancy of potato tuber? [CBSE '01] (1) Gibberellin (2) IAA (3) ABA (4) Zeatin Hormone responsible for senescence is [CBSE '01] (1) ABA (2) auxin (3) GA (4) cytokinin Which one is a long-day plant? [CBSE '01] (1) Tobacco (2) Glycine max (3) Mirabilis jalapa (4) Spinach Proteinaceous pigment which control activities concerned with light is [CBSE '01] (1) phytochrome (2) chlorophyll (3) anthocyanin (4) carotenoids Crescograph was invented by [BHU '01] (1) F.W. Went (2) C.V. Raman (3) J.C. Bose (4) Charles Darwin Which of the following controls flowering in long day plants and sex expression in certain species? [BHU '01] (1) Auxin (2) Cytokinin (3) Gibberellin (4) Ethylene Growth of lateral bud is promoted by [BHU '01] (1) auxin (2) cytokinin (3) gibberellin (4) abscissic acid A stress hormone is [BHU '01] (1) IAA (2) NAA (3) ABA (4) IBA In longitudinal section of root tip various regions of growth may be seen in sequence from top towards root cap as [AMU '01] (1) cell division, cell elongation, cell maturation (2) cell maturation, cell elongation, cell division (3) cell elongation, cell maturation, cell division (4) cell maturation, cell division, cell elongation Abscisic acid plays active role in [AMU '01] (1) dormancy of seeds (2) cell division (3) enhance senescense (4) shoot elongation A long day plant flowers only if exposed to a light period [AMU '01] (1) more than its critical day length. (2) less than its critical day length. (3) equal to its critical day length. (4) slightly less than its critical day length.

638 23.

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BIOLOGY Seed dormancy is due to the [BHU '03, CBSE '02] (1) ethylene (2) abscisic acid (3) IAA (4) starch A plant hormone used for inducing morphogenesis in plant tissue culture is [AFMC '02] (1) ethylene (2) gibberellin (3) cytokinin (4) abscisic acid The hormone reducing transpiration rate by inducing stomatal closure is [BHU 2000, '02] (1) ABA (2) ethylene (3) cytokinin (4) auxin An efficient root inducing chemical useful in Horticulture is [AMU '02] (1) GAA (2) IBA (3) NAA (4) 2, 4-D What reason will you assign for coconut milk used in tissue culture? [CBSE '2000, '03] (1) Gibberellins (2) Cytokinins (3) Auxins (4) Ethylene Differentiation of shoot is controlled by [CBSE '03] (1) high gibberellin : cytokinin ratio (2) high auxin : cytokinin ratio (3) high cytokinin : auxin ratio (4) high gibberellin : auxin ratio Richmond-Lang effect is concerned with [AFMC '03] (1) delay in senescence (2) breaking dormancy (3) suppression of apical dominance (4) cell elongation Auxin in plant means for [BHU '03] (1) cell elongation (2) fruit ripening (3) cell division (4) inhibit the root growth Primary precursor of IAA is [BHU '03] (1) phenylalanine (2) tyrosine (3) tryptophan (4) leucine Ageing is retarded by [BHU '03] (1) ABA (2) CKN (3) GA (4) C2H4 Substance related with phototropism in shoot is [AMU '03] (1) ethanol (2) cytokinin (3) auxin (4) gibberellin One set of a plant was grown at 12 hours day and 12 hours night period cycles and it flowered while in the other set night phase was interrupted by flash of light and it did not produce flower. Under which one of the following categories will you place this plant? [CBSE '04] (1) Long day (2) Darkness neutral (3) Day neutral (4) Short day

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Leaf abscission, fruit fall, and bud dormancy occurs by which phytohormone ? [AFMC '04] (1) Auxin (2) Cytokinin (3) Gibberellin (4) Abscissic acid Which of the following induces flowering in long day plants? [BHU '04] (1) Gibberellin (2) Cytokinin (3) Auxins (4) Ethylene Hormone responsible for bolting is [AMU '04] (1) auxin (2) kinetin (3) ethylene (4) cytokinin A physiological response to the duration of light and darkness is a [AMU '01, Orissa '04] (1) daily phase cycle (2) circadian rhythm (3) biological clock (4) photoperiodism Which of the following does not exhibit seed dormancy ? [UP CPMT '04] (1) Phaseolus (2) Rhizophora (3) Xanthium (4) Cassia Pruning of plants promotes branching because the axillary buds get sensitized to [AIIMS '04] (1) ethylene (2) gibberelins (3) cytokinins (4) indole acetic acid Apical dominance in plants is caused by [AIEEE '04] (1) high concentration of auxins in the terminal bud. (2) high concentration of gibberellins in the apical bud. (3) high concentration of auxins in the lateral bud. (4) absence of auxins and gibberellins in apical bud. Intercalary meristem results in [Kerala CET '04] (1) secondary growth (2) primary growth (3) apical growth (4) secondary thickening Which hormone is responsible for apical growth? [Bihar CECE '04] (1) IAA (2) ABA (3) GA (4) All of these Senescence is inhibited by [Orissa '04] (1) ethylene (2) gibberellic acid (3) cytokinin (4) abscisic acid Intercalary meristem occurs in [J&K PMT '04] (1) mint (2) grasses (3) Both (1) & (2) (4) none of these In callus culture, roots can be induced by the supply of [BHU '05] (1) auxin (2) cytokinin (3) gibberellin (4) ethylene Which of the following is responsible for synthesis of enzyme in seed germination? [BHU '05] (1) IAA (2) Gibberellin (3) Cytokinin (4) Ethylene The most common auxin is [AMU '05] (1) GA (2) ABA (3) kinetin (4) IAA

PLANT GROWTH AND DEVELOPMENT 49.

50.

51.

52.

Gibberellin promotes cell division and elongation in [AMU '05] (1) leaves (2) roots (3) shoots (4) All of these Gibberellins can promote seed germination because of their influence on [AIIMS '05] (1) rate of cell division (2) production of hydrolysing enzymes (3) synthesis of abscisic acid (4) absorption of water through hard seed coat The stress hormone that helps plant respond to drought is [Kerala '05] (1) auxin (2) abscisic acid (3) cytokinin (4) ethylene Match the growth regulators in column-I with the processes in column-II and choose the correct combination. Column-I

53.

54.

55.

56.

(a) (b) (c) (d) (1) (2) (3) (4) (a)

Column-II

Auxin (i) Colouring test in lemon Gibberellin (ii) Cell division test in plants Cytokinin (iii) Avena curvature test Ethylene (iv) Dwarf corn test (a) – (iii), (b) – (iv), (c) – (ii), (d) – (i) (a) – (i), (b) – (iv), (c) – (ii), (d) – (iii) (a) – (iv), (b) – (iii), (c) – (i), (d) – (ii) (a) – (ii), (b) – (i), (c) – (iv), (d) – (iii) Cytokinins suppress the synthesis of chlorophyll. [Kerala '05] (b) Auxins control apical dominance. (c) Gibberellins promote shoot elongation. (d) Abscissic acid enable seeds to withstand desiccation. Which of the above statements are correct ? (1) (a) and (b) only (2) (b) and (c) only (3) (a) and (c) only (4) (b), (c) and (d) only Both in callus and suspension cultures commonly used auxin is [Kerala '05] (1) NAA (2) IBA (3) 2-4 D (4) 2, 4, 5-Trichlorophenoxy acetic acid Leaf fall occurs in a tree when there is an increase in the concentration of [Karnataka '05] (1) abscisic acid (2) auxin (3) gibberellin (4) cytokinin In tissue culture which one of the following pairs of substances are used to induce shoot formation and root formation respectively during organogenesis? [APMEE '05] (1) Hydrogen peroxide and chlorine (2) Auxins and cytokinins (3) Cytokinins and auxins (4) Ethylene and abscisic acid

639 57.

58.

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66.

67.

Effect of low temperature which shortens vegetative period and hasten flowering is [Orissa '05] (1) photoperiodism (2) transpiration (3) vernalization (4) photolysis The shedding of leaves, flowers and fruits due to change in hormonal balance in plants is referred as[JK CMEE '05] (1) senescence (2) abscission (3) photoperiodism (4) vernalization Auxin causes cells to absorb water from hypertonic media because [Manipal '05] (1) it lowers transpiration rate. (2) it increases rate of cellular respiration causing more production of ATP molecules thus facilitating active water absorption. (3) it increases solute potential of the cells. (4) it increase rate of transpiration. How does prunning help in making the hedge dense? [AFMC'08,09, CBSE '06] (1) It frees axillary buds from apical dominance. (2) The apical shoot grows faster after pruning. (3) It releases wound hormones. (4) It induces the differentiation of new shoots from the rootstock. An enzyme that can stimulate germination of barley seeds is [CBSE '06] (1) lipase (2) protease (3) invertase (4) α-amylase Treatment of seed at low temperature under moist conditions to break its dormancy is called [CBSE '06] (1) vernalization (2) chelation (3) stratification (4) scarification Gibberellin was first extracted from [AFMC 2006] (1) Gibberella fujikuroi (2) Gelidium (3) Gracelaria (4) Aspergillus Phytochromes are [AFMC '06] (1) chemicals regulating flowering. (2) chemicals regulating growth from seed to adulthood. (3) hormones regulating growth from seed to adulthood. (4) regulators synthesized by plants and influencing physiological process. The bioassay of auxin is [BHU '05, AIIIMS '06] (1) avena curvature test (2) callus formation (3) culture of fungus (4) seed dormancy The hormone responsible for ripening of fruits is [Bihar CECE'04, BHU 2000, AMU'06] (1) ethylene (2) cytokinin (3) auxin (4) ABA Leaf abscission is caused by [BHU '06] (1) ABA (2) cytokinin (3) auxin (4) gibberellin

640 68.

BIOLOGY 80.

The factor influencing process of flowerings is [BHU '06]

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(1) amount of chlorophyll (2) soil water (3) soil pH (4) photoperiod Which of the following is not an influence of auxins? [AMU '06] (1) Apical dominance (2) Parthenocarpy (3) Tropic movements (4) Bolting Which plant hormone promotes seed, bud dormancy and causes stomatal closure ? [AMU '06] (1) IAA (2) Abscisic acid (3) GAl (4) Cytokinin Phytotron is device for (CET Chd '06] (1) induction of mutations (2) measuring wind velocity (3) measuring electron flow (4) growing plants under controlled conditions. In reference to photoperiodism which of the following is a long day plant? [Gujarat CET '06] (1) Xanthium (2) Poppy (3) Paddy (4) Soyabean To make stored food available for germination with which hormone seed should be treated? [Gujarat CET '06] (1) Gibberellins (2) Auxin (3) Abscisic acid (4) Cytokinin During which of the following phase of growth, cell increases in volume? [Gujarat CET '06] (1) Cell division (2) Differentiation (3) Exponential (4) Enlargement Abscisic acid (ABA) promotes [COMEDK's '06] (1) stem elongation (2) flower initiation (3) triple response (4) detachment of leaf, flower and fruit The common biosynthetic inhibitor of gibberellic acid is [Orissa '06] (1) CCC (2) jasmonic acid (3) citric acid (4) lactic acid Which of the following phytohormones is not naturally occurring ? [BV '06] (1) 1AA (2) 2, 4–D (3) Gibberellic acid (4) 6-furfuryl aminopurine Which of the following is not a function of cytokinin? [AMU PMDC '06] (1) Delay in senescence. (2) Breaking of seed dormancy. (3) Promoting bud dormancy. (4) Promoting stomatal opening. Gibberellins induce flowering in [R PMT '06] (1) short day plants (2) long day plants (3) neutral day plants (4) morphogenesis

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The method of inducing early flowering by pretreatment of seeds with a certain low temperature is called [Kerala '06] (1) photoperiodism (2) abscission (3) vernalization (4) phototaxis Choose the wrongly matched pair from the following [Kerala '06] (1) Auxins – “to grow” (2) Gibberellins – “gibberella fujikurai” (3) Cytokinins – Herring sperm DNA (4) Abscisic acid – Flowering hormone Which one of the following pairs, is not correctly matched? [CBSE '07] (1) Gibberellic acid - Leaf fall (2) Cytokinin - Cell wall elongation (3) IAA - Cell wall elongation (4) Abscissic acid - Stomatal closure. “Foolish seedling’’ disease of rice led to the discovery of [CBSE '07] (1) ABA (2) 2, 4-D (3) IAA (4) GA Removal of apical (terminal) bud of a flowering plant (or pruning of a flowering plant) leads to [CBSE '93, 2000, AFMC '07] (1) formation of new apical buds. (2) formation of adventitious roots on the cut side. (3) early flowering (or stopping of floral growth). (4) promotion of lateral branches. Which one of the following is a natural growth inhibitor? [BHU '07] (1) NAA (2) ABA (3) IAA (4) GA Which one is a short day plant ? [BHU '07] (1) Brassica compestris (2) Raphanus sativus (3) Glycine max (4) Papaver somniferum Florigen is produced in the region of [BHU '07] (1) leaves (2) fruit (3) root (4) trunk Growth promoting hormone is [BHU '07] (1) IAA (2) Gibberellin (3) 2,4-D (4) ABA Auxin originates at the tip of the stem and controls growth elsewhere. The movement of auxin is largely [Karnataka CET '07] (1) acropetal and basipetal (2) centripetal (3) basipetal (4) acropetal The process in which mature differentiated cells reverse to meristematic activity to form callus is called [Karnataka CET '07] (1) cytodifferentiation (2) redifferentiation (3) dedifferentiation (4) differentiation

PLANT GROWTH AND DEVELOPMENT 91.

92.

93.

94.

95.

96.

97.

98.

99.

In tissue culture roots can be induced by [Karnataka CET '07] (1) no cytokinin and only auxins. (2) higher concentration cytokinin and lower concentration auxins. (3) lower concentration of cytokinin and higher concentration of auxins. (4) only cytokinin and no auxins. With respect to photoperiodism, which of the following are long day plants? [Gujarat CET '07] (1) Wheat, Poppy, Soyabean (2) Wheat, Poppy, Beet (3) Wheat, Oat, Soybean (4) Wheat, Xanthium, Paddy The period between formative phase and maturation phase of plant growth is known as [HP PMT '07] (1) grand period of growth (2) stationary phase (3) lag phase (4) phase of elongation Plants requiring exposure to light for less than critical period in order to flower are called [HP PMT '07] (1) long day plants (2) day neutral (3) intermediate day plants (4) short day plants Rapid and dramatic increase in shoot length is called [J&K PMT '07] (1) bolting (2) scarification (3) night break effect (4) triple response growth IAA and serotonin are derived from which of the following? [DPMT '07] (1) Tryptophan (2) Tyrosine (3) Phenylalanine (4) None of these The natural plant hormone isolated from corn kernels and coconut milk is [Kerala CET '07] (1) florigen (2) GA3 (3) free auxins (4) zeatin 6-furfuryl amino purine, 2, 4-dichlorophenoxy acetic acid and indole-3 acetic acid are examples respectively for [Kerala CET '07] (1) synthetic auxin, kinetin and natural auxin. (2) gibberellin, natural auxin and kinetin. (3) natural auxin, kinetin and synthetic auxin. (4) kinetin, synthetic auxin and natural auxin. Which of the following is incorrectly matched ? [Kerala CET '07] (1) Explant – Excised plant part used for callus formation (2) Cytokinins – Root initiation in callus (3) Somatic embryo – Embryo produced from a vegetative cell (4) Anther culture – Haploid plants

641 100. The pine apple which under normal conditions is difficult to blossom has been made to produce fruits throughout the year by the application of [WB '07] (1) IAA, IBA (2) NAA, 2, 4–D (3) phenyl acetic acid (4) cytokinins 101. Pruning of plants promotes branching because the axillary buds get sensitized to [Punjab PMT '07] (1) ethylene (2) cytokinin (3) gibberellin (4) indole acetic acid 102. In short day plant flowering is interrupted when [Punjab PMT '07] (1) dark condition is interrupted by white light or red light. (2) dark condition is interrupted by far-red light. (3) dark condition is interrupted by red followed by far red light. (4) in short day plants flowering cannot be interrupted. 103. Senescence as an active developmental cellular process in the growth and functioning of a flowering plant, is indicated in [CBSE '08] (1) vessels and tracheid differentiation (2) leaf abscission (3) annual plants (4) floral parts 104. Cell elongation in internodal regions of the green plants takes place due to [CBSE '04, AFMC '08] (1) indole acetic acid (2) cytokinins (3) gibberellins (4) ethylene 105. Treatment of seed at low temperature under moist conditions to break its dormancy is called [AFMC '08] (1) scarification (2) vernalization (3) chelation (4) stratification 106. A hormone delaying senescence is [BHU '08] (1) auxin (2) cytokinin (3) ethylene (4) gibberellin 107. The potent weed killer is [AMU '08] (1) gibberellin (2) 2,4-D (3) abscisic acid (4) ethylene 108. The geotropic response of roots is mediated by [AMU '08] (1) cytokinin (2) auxin (2) phytochrome (4) light stimulus 109. To avoid excessive water loss during severe drought stress, the closure of stomata is signalled by the production of [AMU '08] (1) IAA (2) NAA (3) ABA (4) IBA 110. Intercalary meristem is a derivative of [KCET '08] (1) promeristem (2) lateral meristem (3) secondary meristem (4) primary meristem

642

BIOLOGY

111. Identify two of the following phytohormones which regulate the stomatal movements. [EAMCET '08] (a) IAA (b) GA3 (c) Zeatin (d) ABA The correct pair is (1) a, c (2) b, c (3) c, d (4) b, d 112. One hormone helps in ripening of fruits while the other stimulates closure of stomata. These are respectively [Kerala PMT '08] (1) abscisic acid and auxin (2) ethylene and abscisic acid (3) abscisic acid and ethylene (4) ethylene and gibberellic acid 113. Pick out the correct statements [Kerala PMT '08] (a) Cytokinins specially help in delaying senescence. (b) Auxins are involved in regulating apical dominance. (c) Ethylene is specially useful in enhancing seed germination. (d) Gibberellins are responsible for immature falling of leaves. (1) a and c only (2) a and d only (3) a and b only (4) b and c only 114. Match list I and list II and select the correct option. [Kerala PMT '08] List-I

115.

116.

117.

118.

List-II

(a) Auxin (I) Herring sperm DNA (b) Cytokinin (II) Inhibitor of growth (c) Gibberellin (III) Apical dominance (d) Ethylene (IV) Epinasty (e) Abscisic acid (V) Induces amylase synthesis (1) a-III, b-I, c-V, d-IV, e-II (2) a-IV, b-V, c-I, d-III, e-II (3) a-II, b-I, c-V, d-III, e-IV (4) a-III, b-I, c-V, d-II, e-IV One set of a plant was grown at 12 hours day and 12 hours night period cycles and it flowered while in the other set night phase was interrupted by flash of light and it did not produce flowers. Under which one of the following categories will you place this plant ? [AFMC '08] (1) Day neutral (2) Short day (3) Long day (4) Darkness neutral One of the synthetic auxin is [CBSE '09] (1) IAA (2) GA (3) IBA (4) NAA Which one of the following acids is a derivative of carotenoids ? [CBSE '09] (1) Indole-3 -acetic acid (2) Gibberellic acid (3) Abscisic acid (4) Indole butyric acid The plants bend towards light because [CET Chd. '09] (1) the stem likes sunlight. (2) the roots send the message to the stem to do so. (3) due to secretion of growth promoting substances at the tip. (4) the food material is translocated from leaves to stem causing bending.

119. In a plant growing under dark condition, the leaves turn light coloured, internodes become much elongated and it is termed as [CET Chd. '09] (1) vernalization (2) etiolation (3) phyllotaxy (4) chlorosis 120. Etiolation in plants is caused when [DPMT '09] (1) they have mineral deficiency. (2) they are grown in dark. (3) they are grown in intense light. (4) they are grown in blue light. 121. Interfascicular cambium is a [COMEDK's '09] (1) intercalary meristem (2) apical meristem (3) non-calary meristem (4) secondary meristem 122. Compare the statement A and B [KCET '09] Statement A. Auxins promote apical dominance by suppressing the activity of lateral buds Statement B. In moriculture, periodic pruning of shoot tips is done to make mulberry plants bushy. Select the correct description : (1) Both the statements A and B are correct and A is the reason for B. (2) Statement A is correct and B is wrong. (3) Statement A is wrong and B is correct. (4) Both the statements A and B are correct and A is not reason for B. 123. Which of the following hormones does not naturally occur in plants? [KCET '09] (1) 2,4–D (2) IAA (3) ABA (4) GA 124. The discovery of gibberellins is related with which one of the following ? [WB '09] (1) Blast disease of rice (2) Bakanae disease of rice (3) Early blight disease of potato (4) Rust disease of wheat 125. Cut flowers and vegetables can be kept fresh for a long period by which plant hormone? [Manipal '09] (1) Auxin (2) Ethylene (3) Gibberellin (4) Cytokinin 126. Assertion (A) : Apical and intercalary meristem contribute to the growth in length while the lateral meristems bring increase in girth in maize. Reason (R) : Apical and intercalary meristems always increase the height of plants. [EAMCET '09] The correct answer is : (1) If both A and R are true and R is the correct explanation of A. (2) Both A and R are true, but R is not correct explanation of A. (3) A is true but R is false. (4) A is false and R is true.

PLANT GROWTH AND DEVELOPMENT 127. Seedless fruits are produced through the application of [MHT CET '09] (1) GA (2) ethylene (3) maleic hydrazide (4) 2, 4, 5-T 128. One of the synthetic auxin is: [CBSE PMT 2009] (1) IAA (2) GA (3) IBA (4) NAA 129. Which one of the following acids is a derivative of carotenoids ? [CBSE PMT 2009] (1) Indole-3 -acetic acid (2) Gibberellic acid (3) Abscisic acid (4) Indole butyric acid 130. The ripening of fruits can be hastened by treatment with [Kerala PMT 2009] (1) gibberellins (2) cytokinins (3) ethylene gas (4) auxin 131. Match the following and choose the correct combination [Kerala PMT 2009] Column I Column II (1) Zeatin 1. Flowering hormone (2) Florigen 2. Synthetic auxin (3) IBA 3. Cytokinin (4) NAA 4. Natural auxin (1) A – 3, B – 4, C – 1, D – 2 (2) A – 2, B – 1, C – 4, D – 3 (3) A – 1, B – 2, C – 3, D – 4 (4) A – 3, B – 1, C – 4, D – 2 132. The response of different organisms to environmental rhythms of light and darkness is called [Kerala PMT 2009] (1) phototropism (2) phototaxis (3) photoperiodism (4) vernalization 133. Phototropic curvature is the result of uneven distribution of [CBSE '10] (1) gibberellin (2) phytochrome (3) cytokinin (4) auxin 134. Auxin is responsible for [BHU '07, Orrisa '10, J&K '10, AFMC'10] (1) apical dominance (2) ripening of fruit (3) elongation of genetically dwarf plants (4) induction of vernalization 135. Which of the following hormone prevents ripening of fruit? [AFMC '10] (1) Gibberellin (2) Ethylene (3) Cytokinin (4) ABA 136. Which one of the following plant functions is not controlled by auxins ? [AMU 2010] (1) Apical dominance (2) Phototropism (3) Growth (4) Photosynthesis

643 137. Coconut milk stimulates cell division as it is a rich source of [AFMC '09, AMU '10] (1) auxin (2) cytokinin (3) gibberellin (4) ethylene 138. The study of phototropic response lead to the discovery of [AMU 2010] (1) cytokinin (2) gibberellin (3) ethylene (4) auxin 139. One of the commonly used plant growth hormone in tea plantation is [CBSE Mains '10] (1) zeatin (2) abscisic acid (3) indole-3 acetic acid (4) ethylene 140. Which one of the following synthetic growth regulators is used to promote synchronized flowering in pineapple ? [Karnataka '10] (1) Benzyl aminopurine (2) Phenyl mercuric acetate (3) Indole butyric acid (4) 2–chloroethylphosphonic acid 141. Cytokinins which have specific effect on cytokinesis are modified forms of [HP PMT '10] (1) cytocin (2) adenine (3) guanine (4) thiamine 142. Vernalization phenomenon of plants depends on exposure to [HP PMT '10] (1) temperature (2) moisture (3) soil composition (4) major and minor elements 143. The process of vernalization is [MH CET '10] (1) aerobic (2) anaerobic (3) unaffected by aerobic or anaerobic condition. (4) dependent upon starvation conditions. 144. Which can counteract the abscission–promoting effect of ethylene ? [MH CET '10] (1) Gibberellins (2) Abscisic acid (3) Auxin (4) Antiauxin 145. Which of the following demonstrates the process associated with the abscission of a leaf ? [Gujarat CET '10] (1) In the leaf, the concentration of both auxin and ABA decreases. (2) In the leaf, the concentration of both auxin and ABA increases. (3) Reduction in ABA concentration and increase of auxin concentration in the leaf. (4) Reduction in concentration of auxin and increase of concentration of ABA in the leaf.

644 146. Phototropic curvature is the result of uneven distribution of: [CBSE PMT 2010] (1) gibberellin (2) phytochrome (3) cytokinins (4) auxin 147. Coiling of garden pea tendrils around any support is an example of: [CBSE PMT 2010] (1) thigmotaxis (2) thigmonasty (3) thigmotropism (4) thermotaxis 148. Dwarfness can be controlled by treating the plant with [CBSE '92, '02, HP PMT'11] (1) cytokinin (2) gibberellic acid (3) auxin (4) antigibberellin 149. Auxanometer is required for [J&K CMEE '05, AFMC '10, J&K CET '11] (1) studying rate of transpiration. (2) measuring rate of respiration. (3) finding out rate of photosynthesis. (4) calculating rate of growth. 150. Transport of cytokinin in the plant body is [Chd. CET '11] (1) basipetal (2) lateral (3) acropetal (4) on all sides 151. The rosette habit of cabbage can be changed by application of [K CET '11] (1) ABA (2) IAA (3) GA (4) Ethaphon 152. Day neutral plants relate to [J&K CET '11] (1) loss of activity during day time (2) flowering in all possible photoperiods (3) overactive during day time (4) no flowering in any photoperiods 153. Which wavelength of light is responsible for best flowering? [MP PMT '11] (1) Red light (2) Green light (3) Blue light (4) Day light 154. Opening and closing of flowers represent a kind of [AFMC 2011] (1) nastic movement (2) tropic movement (3) mutation (4) autonomic movement 155. Which one of the following pairs, is not correctly matched? [JIPMER-2011] (1) Abscisic acid — Stomatal closure (2) Gibberellic acid — Leaf fall (3) Cytokinin — Cell division (4) IAA — Cell wall elongation 156. Exponential growth in plants can be expressed as Kerala PMT 2011] (1) Lt = L0+ rt (2) Le = Lt rt rt (3) W1 = W0e (4) W1 = W0e rt

BIOLOGY 157. Which one of the following pairs is incorrectly matched? [Kerala PMT 2011] (1) adenine derivative - kinetin (2) carotenoid derivative - ABA (3) terpenes - IAA (4) indole compounds - IBA 158. Through their effect on plant growth regulators, what do the temperature and light control in the plants? [CBSE '12] (1) Apical dominance (2) Flowering (3) Closure of stomata (4) Fruit elongation 159. Which one of the following generally acts as an antagonist to gibberellins? [CBSE '12] (1) Zeatin (2) Ethylene (3) ABA (4) IAA 160. Vernalization stimulates flowering in [CBSE '12] (1) zamikand (2) turmeric (3) carrot (4) ginger 161. Through their effect on plant growth regulators, what do the temperature and light control in the plants? [CBSE'2012M] (1) Apical dominance (2) Flowering (3) Closure of stomata (4) Fruit elongation 162. Which one of the following generally acts as an antagonist to gibberellins? [CBSE'2012M] (1) Zeatin (2) Ethylene (3) ABA (4) IAA 163. Vernalization stimulates flowering in [CBSE'2012M] (1) zamikand (2) turmeric (3) carrot (4) ginger 164. Through their effect on plant growth regulators, what do the temperature and light control in the plants? [CBSE PMT 2012M] (1) Apical dominance (2) Flowering (3) Closure of stomata (4) Fruit elongation 165. Which one of the following generally acts as an antagonist to gibberellins? [CBSE PMT 2012M] (1) Zeatin (2) Ethylene (3) ABA (4) IAA 166. Vernalization stimulates flowering in [CBSE PMT 2012M] (1) zamikand (2) turmeric (3) carrot (4) ginger 167. Gibberellins can promote seed germination because of their influence on [AIIMS 2012] (1) Rate of cell division (2) Production of hydrolyzing enzymes (3) Synthesis of abscisic acid (4) Absorption of water through hard seed coat. 168. Coconut water is rich in [AFMC 2012] (1) auxins (2) gibberellins (3) abscisic acid (4) cytokinin

PLANT GROWTH AND DEVELOPMENT 169. Which one of the following is a natural growth inhibitor ? [JIPMER-2012] (1) NAA (2) ABA (3) IAA (4) GA 170. Apical dominance is caused by [JIPMER-2012] (1) auxin (2) gibberellin (3) kinetin (4) ABA 171. Which of the following plant is LDP? [JIPMER-2012] (1) Xanthium (2) Soyabean (3) Wheat (4) Tobacco 172. Phytochrome is present in [JIPMER-2012] (1) vascular cryptogam (2) prokaryotes (3) flowering plants (4) algae 173. One hormone is used to speed up the malting process in barley, another is used to promote flowering in pineapple, while the third helps in the delay of leaf senescence. These are respectively [Kerala PMT 2012] (1) auxin, gibberellin and cytokinin (2) gibberellin, cytokinin and auxin (3) gibberellin, auxin and cytokinin (4) cytokinin, auxin and gibberellin 174. Which of the following is not a physiological effect of auxin? [Kerala PMT 2012] (1) Initiates rooting in stem cuttings. (2) Promotes flowering. (3) Prevents fruit and leaf drop at early stages (4) Promotes bolting. 175. Which one of the following is not used for ex-situ plant conservation ? [NEET 2013] (1) Seed banks (2) Shifting cultivation (3) Botanical Gardens (4) Field gene banks 176. During seed germination its stored food is mobilized [NEET 2013] (1) Cytokinin (2) ABA (3) Gibberellin (4) Ethylene 177. The pineapple which under natural conditions is difficult to blossom has been made to produce fruits throughout the year by application of [NEET Kar. 2013] (1) IAA, IBA (2) NAA, 2, 4-D (3) Phenyl acetic acid (4) Cytokinin 178. Study the following statements. [AIIMS 2013] I. “X” hormone promotes root growth and root hair formation thus helping the plants to increase their absorption surface. II. “Y” hormone induces flowering in mango and also promotes rapid internode/petiole elongation in deep plants and hence helping leaves or upper parts of shoot above water.

645

179.

180.

181.

182.

183.

III. “Z” hormone inhibits the seed germination, increase the tolerance of plant to various stresses, play import in seed development, maturation and dormancy. Identify the correct names of hormones marked as ‘X’, ‘Y’ & ‘Z’. (1) Y = ABA; X = Auxin; Z = GA (2) Z = GA; X = Auxin; Y = C2H4 (3) Y = Auxin; X = C2H4; Z = GA (4) Y = C2H4; X = C2H4; Z = ABA Assertion : Dark period plays more important part in flowering than light period. Reason : Flowering occurs in short-day plant if the dark period is interrupted by light break. [AIIMS 2013] (1) If both Assertion and Reason are correct and Reason is the correct explanation of Assertion. (2) If both Assertion and Reason are correct, but Reason is not the correct explanation of Assertion. (3) If Assertion is correct but Reason is incorrect. (4) If Assertion is incorrect but Reason is correct. Select the activities associated with gibberellins. [Kerala PMT 2013] (a) Apical dominance (b) Good herbicides (c) Promotes bolting (d) Delay senescence (e) Stimulates closure of stomata (1) (a) and (b) only (2) (b) and (c) only (3) (b) and (d) only (4) (c) and (d) only Match the following and choose the correct combination from the options given. [Kerala PMT 2013] Column I: Column II: Growth Regulator Action (A) Abscisic acid 1. Delays leaf senescence (B) Ethylene 2. Inhibits seed germination (C) Cytokinin 3. Herbicide (D) Auxin 4. Hastens fruit ripening (1) A-2, B-4, C-1, D-3. (2) A-1, B-2, C-3, D-4 (3) A-2, B-3, C-4, D-1. (4) A-2, B-1, C-3, D-4 In which of these plants, heterophyllous development occurs due to the environment? [Kerala PMT 2013] (1) Coriander (2) Cotton (3) Larkspur (4) Buttercup Dr. F. Went noted that if coleoptile tips were removed and placed on agar for one hour, the agar would produce a bending when placed on one side of freshly-cut coleoptile stumps. Of what significance is this experiment? [AIPMT - 2014] (1) It made possible the isolation and exact identification of auxin. (2) It is the basis for quantitative determination of small amounts of growth-promoting substances. (3) It supports the hypothesis that IAA is auxin. (4) It demonstrated polar movement of auxins.

646 184. A few normal seedlings of tomato were kept in a dark room. After a few days they were found to have become white-coloured like albinos. Which of the following terms will you use to describe them? [AIPMT - 2014] (1) Mutated (2) Embolised (3) Etiolated (4) Defoliated 185. Which one of the following growth regulators is known as 'stress hormone'? [AIPMT - 2014] (1) Abscissic acid (2) Ethylene (3) GA3 (4) Indole acetic acid 186. Dr. F. Went noted that if coleoptile tips were removed and placed on agar for one hour, the agar would produce a bending when placed on one side of freshly-cut coleoptile stumps. Of what significance is this experiment? [AIPMT 2014] (1) It made possible the isolation and exact identification of auxin. (2) It is the basis for quantitative determination of small amounts of growth-promoting substances. (3) It supports the hypothesis that IAA is auxin. (4) It demonstrated polar movement of auxins. 187. A few normal seedlings of tomato were kept in a dark room. After a few days they were found to have become white-coloured like albinos. Which of the following terms will you use to describe them? [AIPMT 2014] (1) Mutated (2) Embolised (3) Etiolated (4) Defoliated 188. Which one of the following growth regulators is known as ‘stress hormone’? [AIPMT 2014] (1) Abscissic acid (2) Ethylene (3) GA3 (4) Indole acetic acid 189. Non-albuminous seed is produced in: [AIPMT 2014] (1) Maize (2) Castor (3) Wheat (4) Pea

BIOLOGY 190. Typical growth curve in plants is : [AIPMT 2015] (1) Linear (2) Stair-steps shaped (3) Parabolic (4) Sigmoid 191. What causes a green plant exposed to the light on only one side, to bend toward the source of light as it grows ? [AIPMT 2015] (1) Green plants seek light because they are phototropic (2) Light stimulates plant cells on the lighted side to grow faster (3) Auxin accumulates on the shaded side, stimulating greater cell elongation there. (4) Green plants need light to perform photosynthesis 192. Auxin can be bioassayed by : [Re-Test AIPMT 2015] (1) Hydroponics (2) Potometer (3) Lettuce hypocotyl elongation (4) Avena coleoptile curvature 193. The photoperiod required to induce flowering is referred to as: [UPCPMT 2015] (1) Slow day length (2) Long day length (3) Critical day length (4) Intervening light period 194. Under water stress, the leaves of plants are found to contain higher concentration of [UPCPMT 2015] (1) Gibberellic acid (2) cyhtokinin (3) Gibberellic acid (4) Auxine

PLANT GROWTH AND DEVELOPMENT

647

EXERCISE - 3 | Test Yourself 1.

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3.

4.

5.

6.

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8.

Parthenocarpic fruit can be produced by the application of which of the following auxin? (1) IBA (Indole butyric acid) (2) IAA (Indole acetic acid) (3) 2, 4-D (2-4 dichlorophenoxy acetic acid) (4) All of the above. To promote the growth of lateral branches of a plant, (1) axillary buds are removed. (2) auxin is applied to apical bud. (3) auxin is applied to the decapitated shoot tip. (4) apical bud is removed. Cytokinins are formed primarily in which area of the plant? (1) Root (2) Stem (3) Tips of shoot (4) Lateral buds and leaves Plant, deficient of element zinc, show its effect on the biosynthesis of which plant growth hormone ? (1) Auxin (2) Cytokinin (3) ABA (4) Ethylene Arithmetic growth includes all the following except (1) constant growth rate. (2) it is found in root and shoot cells. (3) its characteristic graph is sigmoid. (4) it is expressed as Lt = L0 + rt. Which one of the following can regain the capacity to divide mitotically under certain condition? (1) Cork cambium (2) Phellogen (3) Vascular cambium + procambium (4) Phellogen + procambium Which of the following statements correctly explains why a plant becomes bushier when the tip of its shoot is remove? (1) The removal of the plant tip also removes the auxin that is keeping lower buds from developing. (2) Programmed cell death allows the plant to change its form. (3) The concentration of the morphogens sent from the root to stem is increased. (4) None of the above. Differentiation in plant is open because cells / tissues arising out of the same meristem (1) have same structure at maturity. (2) have different structures at maturity. (3) have capacity to disappear their cell walls. (4) have same fate.

9.

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11.

12. 13.

14.

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16.

Which one of the following statement regarding auxin is/are correct? (1) IAA and IBA are natural but NAA, 2 4-D and 2, 4, 5-T are synthetic auxins. (2) IAA and NAA are natural but IBA, 2, 4, 5-T and 2, 4-D are synthetic auxin. (3) NAA and 2, 4, 5-T are natural but IAA, IBA and 2, 4-D are synthetic auxins. (4) IAA, NAA, IAB, 2, 4-D and 2, 4, 5-T are synthetic auxins. Refer the following statements. I. Promotes flowering in pineapple. II. Used to prepare weed free lawn. III. Promotes the abscission of older mature leaves and fruits. The above functions are carried out by (1) GA (2) C2H4 (3) ABA (4) auxin The fruits can be left on the tree longer so as to extend the market period. This is due to which function of GA ? (1) Bolting (2) Delay senescence (3) Internodal elongation (4) Parthenocarpy Cytokinins and ethylene have opposite effects on (1) leaf senescence (2) elongation of stem (3) lateral swelling of stem (4) winter dormancy Cytokinin helps in delay of leaf senescence by (1) increasing more water absorption by root. (2) increasing rate of translocation of organic solutes. (3) promoting nutrients mobilization. (4) formation of adventitious buds. Long day plants flower specially when the (1) light period is lesser than some critical length. (2) light period is greater than some critical period. (3) dark period is less than some critical length. (4) dark period is more than some critical length. Identify two physiological processes (given below) induced by two different phytohormones having a common precursor, which is formed due to catalytic activity of pyruvic dehydrogenase complex. (i) More female flowers in Cucumber. (ii) α-amylase production in barley grain. (iii) Acceleration of fruit ripening in tomato. (iv) Delay in sprouting of potato tubers. The correct combination are (1) i, ii (2) i, iii (3) ii, iv (4) iii, iv Cell elongation in internodal regions of the green plants takes place due to (1) indole acetic acid (2) cytokinin (3) gibberellin (4) ethylene

648 17.

BIOLOGY Match the following columns and choose the correct combination Column A (A) (B) (C) (D) (1) (2) (3) (4)

(3)

Column B

Zeatin Florigen IBA NAA

(i) (ii) (iii) (iv)

Flowering hormone Natural auxin Cytokinin Synthetic auxin

A

B

C

D

iii iii ii i

i iv i ii

iv i iv iii

ii ii iii iv

Directions (18 – 19) : In the following questions, more than one of the answer given may be correct. Select the correct answer and mark it according to the codes given below. Code : (1) a, b and c are correct. (2) a and b are correct. (3) b and d are correct. (4) a and c are correct. 18. The conditions necessary for vernalization are (a) high temperature and water (b) low temperature and oxygen (c) water and carbon dioxide (d) oxygen and water. 19. Abscisic acid (a) induces dormancy. (b) inhibits stomata closure. (c) provides defence against salt and cold stresses. (d) inhibits abscission. 20. Avena curvature test is a bioassay for examining the activity of (1) gibberellin (2) auxin (3) cytokinin (4) ethylene 21. In tissue culture, differentiation of roots and shoots can be controlled by (1) using tissue of light size. (2) giving temperature shocks. (3) change in light intensity. (4) modifying auxin and cytokinin ratios in the medium. 22. Which of the following shows the correct graph of arithmetic growth? (1)

Growth

Time

(4)

Growth

23.

24.

25. 26.

27.

28.

Time The phenomenon of elongation of stem in the plants with rosette habit is known as (1) bolting (2) rosetting (3) phase of elongation (4) Both (2) and (3) Bananas can be prevented from over ripening by (1) refrigeration (2) storing in a freezer (3) dipping in ascorbic acid (4) maintaining them at room temperature. The hormone responsible for phototropism is (1) C2H4 (2) ABA (3) auxin (4) GA Which of the following hormones causes fruits like apple to elongate and improve its shape? (1) GA (2) ABA (3) NAA (4) 2, 4D Which one of the following statement is false? 1. C2H4 promotes leaf senescence. 2. C2 H4 speeds the ripening of fruits. 3. C2H4 causes apical hook formation. 4. C2H4 promotes horizontal growth of seedling and swelling of axis. 5. C2H4 promotes male flowers in cucumber thereby increasing the yield. (1) All the statements (2) I and V (3) II and IV (4) V The following diagram shows four coleoptiles set up at the start of an experiment. razor blade

Growth

Time

(2) Growth

Time

I II III IV Which two coleoptiles will both bend towards the light source? (1) I and II (2) I and IV (3) II and III (4) III and IV

PLANT GROWTH AND DEVELOPMENT 29.

649

Maryland Mammoth Tobacco is a short day plant. Its critical duration of darkness is 10 hours. Under which of the following conditions will Maryland Mammoth tobacco not flower ?

37.

38. (1) 24-hour clock

(2) critical level

(3) critical level light

30.

31.

32.

33.

(4) critical level

critical level dark

Which of the following types of phytohormones resemble the nucleic acids in some structural aspects ? (1) Auxin (2) Cytokinin (3) Gibberellin (4) ABA Which pigment involves in photoperiodic change in plants? (1) Phytochrome (2) Cytochrome (3) Chlorophyll (4) Anthocyanin Which of the following is the effect of a plant hormone, which is synthesized more in absence of light? (1) Inhibits the development of seedless fruits. (2) Responsible for closing of stomata. (3) Induces dormancy of seeds. (4) Length of internodes increases. Which of the following may function to break dormancy in seeds ?

39.

40.

41.

(1) Penetration of the seed coat. (2) Leaching of inhibitory compounds by water. (3) Exposure to fire. (4) All of the above. 34.

35.

36.

You have installed an outdoor gas burning grill on your back patio next to your favorite camellia bush. After the first few chilly nights of using your grill you notice that your camellia, which does not normally lose its leaves, is beginning to do so. Which of the following is the best explanation for what is happening ? (1) The bush is getting too warm next to your grill. (2) Ethylene is a by-product of the gas you are burning and is causing senescence in your plant. (3) Abscisic acid is a by-product of the gas you are burning and is causing senescence in your plant. (4) The plant is a biennial and is bolting. Flowering dependent on cold treatment is known as (1) cryoscopy (2) cryostat (3) vernalization (4) thermotrophy When a plant is not reproducing, most of the cytokinins are produced in its (1) lateral buds (2) shoot apex (3) roots (4) leaves

42.

The natural plant hormones were first isolated from (1) corn germoil and human urine. (2) cotton fruits, spinach leaves and rice plants. (3) human urine and rice seedlings. (4) spinach leaves and fungus Gibberella. You are slicing a green pepper for the pizza you are making at home. As you slice into it you notice lots of tiny pepper plants emerging from the seeds of the pepper. This peeper is exhibiting____ and may be lacking in _____ . (1) parthenocarpy, gibberellins (2) parthenocarpy, abscisic acid (3) vivipary, gibberellins (4) vivipary, abscisic acid Which of the following hormones can replace vernalization? (1) Ethylene (2) Gibberellin (3) Cytokinin (4) Auxin Auxin regulates cell growth by which of the following mechanisms ? (1) Altering the elasticity of cell walls. (2) Altering the plasticity of cell walls. (3) Synthesizing new cell walls. (4) Breaking down cell walls in growing cells. Which of the following is not an effect of gibberellins on plant development in at least some species ? (1) Stem elongation (2) Fruit development (3) Induction of bolting (4) Phototropism Experiments done by Charles Darwin and his son on plant phototropism showed that (1) auxin is produced in the tip of the coleoptile. (2) the tip of the coleoptile is the light receptor of the plant. (3) within coleoptiles, auxin moves laterally away from the source of the light. (4) more cell elongation takes place on the shaded side of the plant.

43.

44.

Pineapple can be made to flower in off season by (1) ethylene

(2)

zeatin

(3) N.A.A.

(4)

temperature

Who demonstrated that cut tip of canary grass seedlings resume phototropic sensitiveness when pasted back in its position? (1) Charles Darwin

(2)

F.W. Went

(3) Boysen Jensen

(4)

Paal

650 45.

BIOLOGY Which of the following events would likely occur if a plant tissue culture is treated with a solution containing a relatively high concentration of cytokinin and a relatively low concentration of auxin ?

48.

(1) Bud and shoot formation; rapid cell expansion; decreased cell division.

49.

(2) Bud and shoot formation; slow cell expansion; increased cell division.

50.

(3) Bud and shoot formation; rapid cell expansion; increased cell division. (4) Root formation; rapid cell expansion; decreased cell division. 46.

Auxanometer is meant for (1) photosynthetic activity (2) growth activity (3) the amount of auxins (4) respiratory activity

47.

51.

Which one of the following is primarily concerned with cell division ? (1) GA3 (2) IAA (3) Cytokinin (4) ANN Hormone responsible for vernalization is (1) florigen (2) colchicine (3) vernalin (4) gibberellin Apical dominance is not affected by (1) indole acetic acid (2) gibberellins (3) indole acetaldehyde (4) indole butyric acid A farmer noticed that some lettuce plants wilted badly and could be grown successfully only if transferred to a very humid greenhouse. What is the most likely cause of the wilting? (1) ABA deficiency

Which one of the following is a long day plant? (1) Bajra

(2)

Soyabean

(3) Tobacco

(4)

Wheat

(2) Inadequate stomatal density (3) Auxin deficiency (4) None of the above

PLANT GROWTH AND DEVELOPMENT

651

ANSWER KEY EXERCISE 1 : NCERT BASED QUESTIONS 1. 6. 11. 16. 21. 26. 31.

(1) (2) (3) (1) (4) (4) (2)

2. 7. 12. 17. 22. 27. 32.

(4) (4) (2) (3) (3) (3) (2)

3. 8. 13. 18. 23. 28. 33.

(1) (2) (4) (2) (3) (1) (2)

4. 9. 14. 19. 24. 29. 34.

(4) (2) (2) (1) (3) (4) (3)

5. 10. 15. 20. 25. 30. 35.

EXERCISE 3 : TEST YOURSELF (4) (3) (2) (3) (1) (2) (4)

1.

(4)

Parthenocarpy refers the development of fruits without fertilization. Such fruits are seedless but otherwise normal in appearance, e.g. banana, pineapple etc. The auxins (IAA, IBA, 2, 4-D) are applied in low concentration in a lanoline paste to the stigma of flower to induce parthenocarpy .

2.

(4)

Apical dominance is the phenomenon where growth in apical bud inhibits the growth of lateral branches. If the apical buds are removed lateral buds will sprout.

3.

(1)

4.

(1)

Zinc is essential for synthesis of tryptophan which is the precursor of indole acetic acid (auxin).

5.

(3)

S-shaped or sigmoid shape curve is obtained in case of geometric growth. In arithmetic growth, on plotting length of the organ at different times, a linear curve is obtained.

6.

(1)

Cork cambium is a de-differentialed cell which can regain the capacity to divide mitotically under certain conditions.

7. 9.

(1) (1)

8. (2) Natural auxin are naturally occurring auxin plants hormone which is called phytohormones. Eg IAA and IBB. These are synthesized in shoot apices, leaf primordial and developing seeds from tryptophan. Some of the important synthetic auxins are 2, 4-D; 2, 4, 5-T (2, 4, 5- trichlorophenoxy acetic acid).

10. 11.

(4) (2)

12. 13.

(1) (3)

14.

(2)

15. 16.

(4) (3)

17. 20.

(1) (2)

EXERCISE 2 : WINDOW TO COMPETITIVE EXAMS 1. 6. 11. 16. 21. 26. 31. 36. 41. 46. 51. 56. 61. 66. 71. 76. 81. 86. 91. 96. 101. 106. 111. 116. 121. 126. 131. 136. 141. 146. 151. 156. 161. 166. 171. 176. 181. 186. 191.

(3) (2) (2) (3) (1) (2) (3) (1) (1) (1) (2) (3) (4) (1) (4) (1) (4) (3) (3) (1) (2) (2) (3) (4) (4) (4) (4) (4) (2) (4) (3) (3) (2) (3) (3) (3) (1) (2) (3)

2. 7. 12. 17. 22. 27. 32. 37. 42. 47. 52. 57. 62. 67. 72. 77. 82. 87. 92. 97. 102. 107. 112. 117. 122. 127. 132. 137. 142. 147. 152. 157. 162. 167. 172. 177. 182. 187. 192.

(1) (3) (1) (3) (1) (2) (2) (2) (2) (2) (1) (3) (3) (1) (2) (4) (1) (1) (2) (4) (1) (2) (2) (3) (4) (1) (3) (2) (1) (3) (2) (3) (3) (2) (3) (2) (4) (3) (4)

3. 8. 13. 18. 23. 28. 33. 38. 43. 48. 53. 58. 63. 68. 73. 78. 83. 88. 93. 98. 103. 108. 113. 118. 123. 128. 133. 138. 143. 148. 153. 158. 163. 168. 173. 178. 183. 188. 193

(1) (3) (1) (2) (2) (3) (3) (4) (1) (4) (4) (2) (1) (4) (1) (3) (4) (1) (4) (4) (2) (2) (3) (3) (1) (4) (4) (4) (1) (2) (3) (2) (3) (4) (3) (4) (2) (1) (4)

4. 9. 14. 19. 24. 29. 34. 39. 44. 49. 54. 59. 64. 69. 74. 79. 84. 89. 94. 99. 104. 109. 114. 119. 124. 129. 134. 139. 144. 149. 154. 159. 164. 169. 174. 179. 184. 189. 194

(4) (1) (4) (3) (3) (1) (4) (2) (3) (4) (3) (2) (4) (4) (3) (2) (4) (3) (4) (2) (3) (3) (1) (2) (2) (3) (1) (3) (3) (4) (1) (3) (2) (2) (4) (3) (3) (4) (3)

5. 10. 15. 20. 25. 30. 35. 40. 45. 50. 55. 60. 65. 70. 75. 80. 85. 90. 95. 100. 105. 110. 115. 120. 125. 130. 135. 140. 145. 150. 155. 160. 165. 170. 175. 180. 185. 190.

(2) (4) (1) (1) (1) (1) (4) (4) (3) (2) (1) (1) (1) (2) (4) (3) (2) (3) (1) (2) (1) (4) (2) (2) (4) (3) (4) (4) (4) (3) (2) (3) (3) (1) (2) (4) (1) (4)

Ripening of Citrus and apple fruits can be delayed with the help of gibberellins. Cytokinins delay the senescence of leaves and other organs by controlling protein synthesis and mobilization of resources. It is called Richmond Lang effect. Long day plants require light period of 14-16 hours for subsequent flowering. Gibberellin promotes internodal elongation in a wide range of species. Thus, internodal elongation phenomenon is called bolting. 18. (3) 19. (4) Avena curvature test is a bioassay for examining the activity of auxin. It is given by F.W. Went.

652

BIOLOGY

21. 25.

(4) (3)

26.

(1)

27. 28.

29.

(4) (4)

(1)

30.

(2)

31.

(1)

32.

(4)

33.

(4)

34.

(2)

35.

(3)

36.

(2)

22. (2) 23. (1) 24. (3) Some tropic movements in plants like phototropism and geotropism are caused due to differential distribution of indole -3- acetic acid (IAA). The ability of GA (gibberellins) to cause increase in length of axis is used to make the stacks of grapes lengthy, thereby allowing the grapes to grow larger. GA4 and GA7 causes apple fruits to elongate and improve shape.

37.

(1)

The first naturally occuring auxin was isolated by Kogl and Haagen-Smit (1931) from human urine. It was identified as auxin-a (auxentriolic acid). Later, in 1934 Kogl, Haagen-Smit and Erxleben obtained another auxin called auxin-b (auxenolonic acid) from corn germ oil (extracted from germinating corn seeds).

38.

(4)

Vivipary is the germination of seeds before they leave the parent plant and is caused by a deficit of abscisic acid.

Auxin concentration increases in shaded area, i.e. auxin are collected in the opposite side of light. Increased concentration of auxin is stimulatory for shoot growth and for this reason, shaded side shows more growth than lighted side. Hence, bending of shoot takes place towards light. Short day plant generally require light period of less than 12 hours and continuous dark period of about 14-16 hours for subsequent flowering. Cytokinin are usually amino purine so they resemble nucleic acids in structural aspects. Phytochrome is a pigment, universally present in green flowering plants, responsible for photomorphogenic changes and developmental process. Gibberellins are the plant hormones causing light inhibited stem growth. This shows that light lowers the level of endogenous gibberellins and stem growth, while in dark it reserves. Gibberellin also produces some other physiological effects on plants like, elongation of internodes and the stem, induce seed germination, breaking dormancy etc. Mechanical abrasion, leaching of inhibitors by water, and exposure to fire may all trigger germination, but actual germination cannot begin until the seed imbibes water. Ethylene gas promotes senescence and is one of the by products of burning your gas grill. You should move your grill or your camellia bush. It is the method of inducing early flowering in plants by pretreatment of their seeds at low temperatures (1–5ºC). The ratios of cytokinins to auxins control cell differentiation in plant tissue culture. When both are present in relatively equal quantities, cells divide but do not differentiate. If there is more of cytokinin than auxin, shoot buds develop from a callus. If there is relatively more auxin than cytokinins roots develop. Thus, proportion of these two hormones control organ formation in callus tissues. Abscissic acid (ABA) is a naturally occurring growth inhibitor.

39.

(2)

Gibberellin overcomes vernalization requirement (low temperature) for flowering.

40.

(2)

Altering the plasticity allows for permanent changes in cell wall shape. The cell wall must increase in size in order for cell growth to occur.

41.

(4)

Gibberellins are involved in all listed phenomena except phototropism.

42.

(2)

Statements a, c, and d are true, but were not demonstrated by the Darwin’s studies.

43.

(3)

Foliar spray of NAA causes flowering in pineapple and litchi.

44.

(1)

The earliest experiments on plant hormones were performed by a British naturalist, Charles Darwin in 1881. While working on canary grass ((Phalaris canariensis), he found that the tip of the coleoptile when exposed to unilateral source of light bends towards the light.

45.

(2)

Cytokinin promotes bud and shoot formation and increased cell division; auxin promotes root formation and increased cell elongation.

46.

(2)

Auxanometer is an instrument for measuring growth in plants.

47.

(4)

Long-day plants usually flower in the spring or early summer; they flower only if the light periods are longer than a critical length, which is usually 9-16 hours. For example, wheat plants flower only when light periods exceed fourteen hours.

48.

(3)

Cytokinins induce cell division in plants and thus influence the plant growth by controlling cell division.

49.

(3)

Vernalin is a hypothetical hormone believed to control the temperature effect in vernalization, and possibly the formation of florigen.

50.

(2)

Apical dominance is caused due to auxins and not due to gibberellins.

51.

(1)

Abscisic acid (ABA) promotes closing of stomata under condition of water stress (wilting). ABA play a significant inhibitory role, notably during physiological stress, e.g., drought, water logging etc. Deficiency of ABA in plant cells cause wilting.

16

Chapter

Digestion & Absorption Part-I : Digestion & Absorption While going through the chapter pay special attention to the following – Terms and Definitions – 1. Coprophagous 3. Chylomicrons

2. 4. 2. 4.

Nucleosidases and nucleotidases Chyme and chyle

Common names – 1. Wisdom teeth

2.

Intrinsic factor

2. 4.

Oxyntic cells Enterogastrone

2. 4.

Child Horse

Dental formulae 1. Rat 3. Rabbit

Organic Nutrients – Carbohydrates, proteins, fat and vitamins.

(II) Inorganic Nutrients – Minerals and water ( For details please refer ‘Vitamins and Minerals’) The carbohydrates, proteins and fats are three Major energy sources and are called Macro nutrients or Proximate principles of food. (For details please refer ‘Biomolecules’) Autotrophs - These organisms synthesize their food from inorganic raw materials, eg. – Plants. Heterotrophs – These include most of the Protozoans and animals which feed on high energy organic molecules. They are of 4-categories. (i)

Parasitic – Generally consume liquid food derived from the body of the host. eg. Tape worm, Ascaris and leech .

Teeth & dental formulas

     

The chemical substances of food are called nutrients and are mainly used for growth, development and energy production. These nutrients fall into two categories. (I)



Galactocemia Sanguivorous

Differences – 1. Thecodont and acrodont teeth 3. Bunodont and lophodont teeth

Functions – 1. Ptyalin 3. Rennin 5. Bile salts

At a Glance Salivary glands Oesophagus Stomach

Duodenum Ileum

Colon



Rectum

654

BIOLOGY (ii)

Symbiotic – Live in association with other animals and obtain food material from each other. eg. Bacteria, E.coli, present in human gut provide vitamins to the human body and in turn consume simple food materials from the intestine. (iii) Saprophytic – Feed on dead organic matter by digesting them outside the body. eg. Housefly, spider. (iv) Holozoic – Consume whole or part of a plant/animal food in liquid or solid form (eg. Animals) They can be classified into three major categories (a) Herbivores – Consume plant material (eg. Rabbit, cows). (b) Carnivores – Consume flesh or animal meat ( eg. Lion, Tiger ) (c) Omnivores – Consume both plants and animals ( eg. Cockroach, crow, rat and man). Special categories of Heterotophs – Connecting Concepts (i) Sanguivores – Feed on Blood of vertebrates, (eg. Leech, louse, bedbug , female mosquito,  Male mosquitoes feed on flower– Vampire bat) nectar and do not transmit malaria, (ii) Insectivores – Feed on insects (eg. Frog, lizard, Ant-eaters ) yellow fever or dengue etc. (iii) Larvivores – Feed on larvae (eg. Gambusia fish - feeds on mosquito larvae ) (iv) Coprophagous – Feed on faecal matter (eg. Pig, rabbit ) (v) Detritivores- Feed directly on decaying organic matter (eg. Earthworm ) (vi) Frugivores – Feed on fruits ( birds, bat, monkey ). Most of the birds are grainivores . (vii) Cannibals – Feed on the members of the same species. (viii) Osmotrophs – Absorb predigested food material through skin by osmosis (eg. Tape worm) (ix) Filter-feeders – Pick-up food particles from the water current, created by ciliary or flagellar beating. (eg. Sponges, Paramecium, Unio). Holozoic Nutrition includes 4-important steps – (i) Ingestion – It means process of feeding. Depending upon the size of food the animals with holozoic nutrition can be classified into two groups. (i) Microphagy – Feeding on microorganism (eg. Paramecium) and macrophagy – feeding on larger organisms (eg. Higher animals) (ii) Digestion – It is enzymatic conversion of complex food material like protein, carbohydrate, lipid and nucleic acid into simpler food materials by hydrolysis (break down by the addition of water). The digestion can be intracellular (eg. Amoeba, Paramecium, sponges) or extra cellular - in cavity.( eg. higher animals). (iii) Absorption – Simpler food materials are taken up by the cells directly or indirectly through the blood or lymph, as in higher organisms. (iv) Egestion – It is removal of undigested waste from the body.

Survey of the digestive systems in different animal-groups In free living protozoans, like Amoeba and Paramecium, the ingestion occurs with the help of pseudopodia or cilia, and the digestion is intracellular (inside food vacuole). In parasitic protozoans, like Plasmodium and Trypanosoma, the food material is taken from the body of the host. •

In Porifers also the digestion is completely intracellular.

•

In Coelenterates the digestion is partly extra cellular (in gastrovascular cavity) and partly intracellular (in nutritive cells ). The egestion occurs through the same opening (mouth) since the coelenterates have blind- sac body plan.

•

In Aschelminthes (eg. Ascaris) the alimentary canal has two openings, i.e. mouth and anus. The body plan in such case is ‘tube –within - tube’.

•

In annelids, arthropods, molluscs etc. the alimentary canal is very well developed. The digestive tract in earthworm includes mouth- buccal cavity –pharynx - oesophagus – gizzard – stomach – intestine (having typhlosole) – rectum – anus. In cochroach the important parts of the gut are – mouth – buccal cavity – pharynx – oesophagus – crop – gizzard – mid gut – hind gut – anus.

DIGESTION & ABSORPTION

655

DIGESTIVE SYSTEM IN HUMAN It includes two main components – (1) Alimentary canal or gut (2) Digestive glands The length of human intestine (small and large) is ~ 4 m. in live conditions. After death it becomes ~7m. The small intestine is the longest part of alimentary canal. The digestive glands can be extrinsic (outside alimentary canal) - eg. Salivary glands, pancreas, liver etc. or intrinsic (inside alimentary canal) - eg. Gastric glands and intestinal glands. Alimentary Canal – It includes following structures :Mouth → Buccal cavity → Pharynx* → Oesophagus → Stomach → Small intestine (Duodenum + Jejunum + Ileum) → Large intestine (Caecum + Colon + Rectum) Anal tube → Anus (*Pharynx is the common passage for food as well as air.) (nasal cavity) buccal cavity

soft palate (epiglottis)

tongue (trachea) oesophagus

diaphragm gall bladder liver duodenum ileum ascending colon caecum appendix

stomach spleen pancreas transverse colon colon descending colon

Oesophagus

Cardiac notch Fundus

Cardiac stomach Pyloric Sphincter

pelvic colon rectum anus

Body of Stomach Pylorus (antrum & canal)

Fig. 16.1 : Digestive system of human (The labelling in parenthesis are of respiratory system)

1.

Mouth and Buccal Cavity – The buccal cavity is lined with stratified squamous epithelium and contains two important structures, ie. Teeth and Salivary glands (openings)

Teeth •

Connecting Concepts They are Ecto-mesodermal in origin. The Enamel is ectodermal where as dentine and pulp  The joint between teeth and jaw cavity are mesodermal in origin.

•

Tooth is differentiated into three parts – (1) Crown – The exposed part of the tooth. (2) Neck – The part of the tooth embedded in the gums. (3) Root – Embedded in the sockets of Jaw bones.

•

The enamel, which forms the covering over crown, is the hardest part in the body and is secreted from Ameloblast layer (ectodermal). ectodermal). This part is secreted before the eruption ectodermal of tooth.

•

The dentine forms the bulk of tooth. It is secreted by Odontoblast layer, forming the covering around pulp cavity. This layer is mesodermal in origin.

•

The pulp cavity is usually closed after the development of teeth. In case of rabbits and rats the pulp cavity of Incisor teeth remains open throughout life, and these teeth keep growing. The tusks in elephant which are modified incisors also have open root and keep growing throughout life.

bone is an immovable joint or fixed joint.

656

BIOLOGY Types of teeth MAMMALS

Enamel Dentine Pulp cavity Gum Neck

C R O W N

R O O T

Dentine Cement

Blood vessels and nerves Fig. 16.2 : C. S. of a tooth

Connecting Concepts 1. Differentiate between : (i) Dental formulae of human Adult and child (ii) Enamel and Dentine (iii) Sanguivorous and Coprophagous animals (iv) Digestion in sponges and cnidarians (v) Lophodont teeth and Bunodont teeth (vi) Proximate and protective principles of food (vii) Cannibals and carnivores

Connecting Concepts

Acrodont – teeth fused with the jaw bones. Polyphyodont – many sets of teeth, and can be replaced many times in life. Homodont - similar type of teeth.

(In frog, teeth are absent in lower jaw) Heterodont teeth – 4-types 1. Incisors – Chisel shaped, for biting or gnawing 2. Canines – Pointed, for tearing flesh. 3. Premolars – For chewing or crushing the food. 4. Molars – For chewing or crushing the food. The premolars & molars are called cheek teeth. Dental formula - It is represented by the teeth of half of the upper jaw and half of the lower jaw. In dental formula I= Incisors, C=Canines, Pm = Premolars and M=Molars. Dental formula for adult human Upper jaw I C Pm M 2 1 2 3 2 + 1 + 2 + 3 (8) × 2 16 = = = = = = 32 Lower jaw I C Pm M 2 1 2 3 2 + 1 + 2 + 3 (8) × 2 16 The total number of cheek teeth (Premolars + Molars) in adult human is 20. Dental formula for milk dentition =

2 1 0 2 2 + 1 + 0 + 2 (5) × 2 10 = = = = 20 2 1 0 2 2 + 1 + 0 + 2 (5) × 2 10

In children the premolars are absent and molars are present in place of premolars. The total number of teeth is 20. • The number of teeth which erupt only once in human are 8 (Pm) + 4 (M)= 12 • The temporary or milk teeth begin to erupt when child is about 6 months old and all teeth (20) are developed by the end of 24 months. The permanent teeth begin to replace milk teeth in the 6th year of age and all teeth (32) are completed by 24 years of age.( Remember that numerical values are same for months and years) • Each 3rd molar of upper and lower jaw (total 4 teeth) is called Wisdom tooth. These teeth are vestigial in human. They erupt late and are not used for crushing the food material. (The total number of teeth in 16-17 years old individual will be 28). I C Pm M 2 0 3 3 2 + 0 + 3 + 3 (8) × 2 16 = = = = = 28 I C Pm M 1 0 2 3 1 + 0 + 2 + 3 (6) × 2 12 • In Rabbit the canines are absent and the space between Incisors and premolars is called Diastema. • In rat the total teeth are 16 with dental formula 1003/ 1003. • The heterodont type of teeth are maximum (44) in horses/pigs with dental formula 3143/ 3143. (Number of teeth in toothed whales are maximum but are homodont type). • 4th premolar of upper jaw and 1st molar of lower jaw form Carnassial teeth in dogs and are used for crushing the bones and tearing the tendons. • The term biscuspid and tricuspid, used in heart valves, is also used for cheek teeth depending upon the number of cusps (projections over the surface of teeth). • The number of roots in each molar of upper jaw is 3, while in each molar of lower jaw it is 2. On the basis of projections over the surface of premolars and molars, the cheek teeth can be divided into following important categories (1) Lophodont teeth – Such teeth bear transverse ridges for crushing the food material, e.g. Elephant and rabbit. Dental formula of Rabbit =

1. Fill in the blanks with suitable words/ statement : (i) ..................... teeth in dogs are used for tearing tendons and crushing bones. (ii) ..................... layer secretes enamel. (iii) Teeth in frog are ..................... , ..................... and ..................... type. (iv) The space between incisors and premolar teeth of rabbit is called ..................... (v) In a person of 17 years the number of cheek teeth is ----------------

FROG

1. Thecodont – teeth present in sockets or alveoli. 2. Diphyodont – two sets of teeth, i.e. milk teeth & permanent teeth. Teeth replaced only once in life 3. Heterodont –different types of teeth.

DIGESTION & ABSORPTION (2) (3)

657

Bunodont teeth – Such teeth bear rounded projection or tubercles, e.g. Human, Monkey & Pig. Hypsodont teeth – The projections in such teeth are triangular or pyramidal in shape, e.g. Horses and Cattle

Salivary glands A typical mammal has 4 - pairs of salivary glands, i.e. Parotid gland, Submaxillary or submandibular gland, sublingual gland and infraorbital or zygomatic gland.

Connecting Concepts  In human there are 3 - pairs of salivary glands (the infraorbital glands are absent). In rabbit the salivary glands are two pairs (the submaxillary glands are absent and infraorbital are doubtful). In frog the salivary glands are lacking.

parotid gland tongue epiglottis sublingual gland

Gullet oesophagus

submandibular gland trachea

Glottis

Fig. 16.3 : Salivary glands in human

(1)

Parotid gland •

It is present near the ear (pinna).

•

It is the largest salivary gland but produces only ~20% of saliva.

•

It contains the enzyme – Ptyalin (α -amylase ). Ptyalin is lacking in predators, e.g. Connecting Concepts Lion & Tiger.  The poison glands of snakes such as cobra, viper and krait are modified The viral infection of these glands causes Mumps.

• (2)

(3)

• The secretion of these glands is poured into buccal cavity through Stensen’s duct. Submaxillary (submandibular) gland •

It is present in the lower side of upper jaw.

•

It produces ~70% of saliva secretion.

• Its secretion reaches buccal cavity through Wharton’s duct. Sublingual gland •

It is present below tongue.

•

It is the smallest salivary gland and produces only ~5% of the secretion.

Its secretion passes through the Duct of Rivinis. The salivary glands are absent in fishes, amphibians and aquatic mammals. Saliva - 1.5 lit/day •



pH – 6 to 7 (slightly acidic). On standing /heating it releases CO2 and becomes alkaline.



Mucus of saliva helps in lubrication.



Saliva also causes denaturation of raw proteins without hydrolyzing them.



Thiocyanate ions, present in saliva, act as anti microbial agent to prevent infection by the microbes that often enter along with the food.



Saliva also has lysozymes.



Ptyalin of saliva acts on boiled starch and converts it into maltose (a disaccharide). Ptyalin Starch (boiled)

Maltose

parotid glands.

658

BIOLOGY 

The digestion of carbohydrate (starch) is the first step in digestion process, and begins in buccal cavity. (In human the buccal cavity and pharynx are separated by a soft palate (Uvula) while in frog the Uvula is absent and the common cavity is called buccopharynx.)



The chewed food, mixed with saliva, called bolus, is swallowed into the oesophagus through gullet. During swallowing (simple reflex) the tongue blocks the mouth, the soft palate closes the internal nostrils and the epiglottis closes glottis due to rising of the larynx.

2. Oesophagus •

It has both voluntary and involuntary muscles and runs through neck and thorax to reach abdominal cavity by piercing the diaphragm. Its lining does not secrete digestive enzymes. The mucus, secreted from goblet cells/glands is added into the food. The salivary digestion continues in oesophagus. The peristalsis in the gut begins from this part. During peristalsis the circular and longitudinal muscles contract alternatively to push the food further into the gut.

• • • •

3. Stomach •

It is differentiated into three main parts, i.e. fundic stomach, body of stomach and pyloric stomach. The fundic as well as body of the stomach are for digestion and contain gastric glands (simple, branched and tubular type). • These glands contain three types of cells. (1) Mucus cells – They secrete mucus which acts as a lubricant. Mucus also prevents the digestion of stomach by proteolytic enzymes, and injury to stomach, by acid. (2) Oxyntic (parietal) cells – They secrete HCl and Castle’s intrinsic factor.* (3) Peptic/zymogen/chief cells – They secrete digestive enzymes. *Castle’s intrinsic factor is secreted from oxyntic cells and helps in the absorption of vitamin-B12, the latter is also known as Castle’s extrinsic factor. The secretion of gastric juice (2.5 lit/day) is stimulated by a hormone – Gastrin, secreted from pyloric mucosa. Functions of HCl• It inactivates ptyalin and maintains pH 1-2 (strongly acidic) • It is germicidal and kills microbes. • It activates pro-enzymes. The secretion of HCl is stimulated by histamine, acetylcholine and gastrin. Enzymes of gastric juice – (1)

HCl Pepsinogon

Pepsin

(Proenzyme)

(Active)

Proteins

(2) Connecting Concepts  Rennin is absent in adult human and probably in children also. The curdling of milk in human is caused by pepsin. Rennin is present in calves but is absent in adult cows.

Proteoses and Peptones

(Remember that Protein digestion in human is normal even in the absence of pepsin enzyme.) HCl Prorennin

Rennin

(Proenzyme)

(Active)

Milk Protein

Calcium paracaseinate

(Casein)

(Curdling of milk)

Pepsin can digest collagen protein (maximum protein in the body) of white fibres.

DIGESTION & ABSORPTION (3)

juice.

659

Gastric Lipase Fat

Fatty acids

(Triglycerides)

(3)

+ Glycerol (1)

Gastric lipase is secreted in small amount. The lipase is mainly secreted in pancreatic

The semi-digested food in stomach is called Chyme. Emptying of stomach Carbohydrate-rich food leaves the stomach first followed by the protein-rich food. The fat rich food takes the maximum time for emptying the stomach. When food reaches duodenum, a part of small Intestine, the Enterogastron (Hormone), secreted from duodenum, inhibits the secretion of gastric juice. (VIP - Vasoactive Intestinal Polypeptide which stimulates secretion of electrolyte and water from intestine also inhibits gastrin secretion. Cud-chewing animals (Ruminants) – eg. Cows, buffalos and camels • In such animals the stomach is 4-chambered and is specialized for cellulose digestion. It contains: (1) Rumen (2) Reticulum (3) Omasum (4) Abomasum • The rumen is the first and the largest part of the stomach. Rumen and reticulum both contain bacteria and protozoans for cellulose digestion ((Remember that cellulase enzyme is not secreted from the gut wall of any vertebrate). The Abomasum is the true stomach as it secretes gastric juice for the digestion of proteins. oesophagus omasum rumen

abomasum

duodenum reticulum Fig. 16.4 : Stomach of a ruminant

4. Small Intestine • •

• • • •

The duodenum contains Brunner’s glands (compound-tubular glands) which secrete mucus for neutralizing the acidity of food. Two-digestive juices are added into duodenum through Sphincter of Oddi (at opening of Ampulla of vater). These are (i) Bile juice, and (ii) Pancreatic juice. Bile juice - 500ml/day. It is greenish fluid which is synthesized in liver and is stored in gall bladder. Gall bladder concentrates the bile juice and also alters its pH. The release of bile juice from gall bladder is stimulated by Cholecystokinin (CCK) hormone of duodenal mucosa. pH = 7.4 (slightly alkaline). It contains bile pigments, bile acid (cholic acid), cholesterol, bile salts and phospholipids.

660

BIOLOGY •

There is no digestive enzyme in bile juice.

•

Bile pigments are excretory products which are formed from non-iron haem. They include Bilirubin and Biliverdin. The bilirubin in intestine breaks-up into stercobilin and urobilin (urochrome). The colour of the urine is due to the presence of urobilin and the colour of faecal matter is due to the presence of stercobilin ((Remember that during jaundice or hepatitis the bilirubin (a toxic chemical) is not excreted out and gets deposited in the body tissues).

Connecting Concepts

 The presence of Gall-stones is called Bile salts – Cholelithiasis. The stones are of 2-types, • They are the sodium salts of cholic acid, i.e. sodium glycocholate and sodium (1) Cholesterol-stones, (2) Calcium taurocholate. bilirubinate-stones. The maximum of They cause emulsification of fats, in which larger particles of fat are converted into smaller the stones (upto 80%) are of cholesterol, • formed by supersaturation of bile. particles and the surface area is increased for better digestion.

•

They increase lipase activity, and also help in absorption of fat products.

•

The peristalsis is also stimulated by these salts.

Pancreatic juice – 1500ml/day •

It is secreted from aciner cells of exocrine part of pancreas.

•

Its secretion is stimulated by Secretin and CCK hormones. Secretin increases the amount of bicarbonates (fluid) in pancreatic juice while CCK increases the amount of enzymes. Both hormones are secreted from duodenal lining.

•

The pH of pancreatic juice is ~ 8. Composition - It contains Trypsinogen, Chymotrypsinogen, Procarboxy-polypeptidases, Nucleases, Amylopsin and Steapsin etc.

Functions of Pancreatic enzymes Enterokinase (1) Trypsinogen

Trypsin

(Proenzyme)

(Active)

Proteins or proteoses and peptones

(The Enterokinase is secreted from ileum.) Trypsin is present throughout the animal kingdom whereas Pepsin is present only in Vertebrates. (Trypsin can not cause curdling of milk but can coagulate blood proteins in sanguivorous animals. It can also not digest collagen protein.)

Connecting Concepts 1. Name the followings : (i) Salivary glands in human (ii) The HCl secreting cells in stomach. (iii) The hormone that inhibits the secretion of gastric juice. (iv) Digestive juice that does not have enzymes. (v) Enzyme that causes curdling of milk in acidic medium (vi) Enzyme that activates trypsinogen (vii) Chemical responsible for the absorption of vitamin B12 (viii) Component of bile that causes emulsification of fat

Polypeptides

(2)

Chymotrypsinogen

Trypsin

Chymotrypsin

(Proenzyme)

(Active)

Proteins or proteoses and peptones

(3)

Polypeptides

(Chymotrypsinogen, like pepsin, can cause curdling of milk, but does it in alkaline medium) Trypsin Pro-carboxypolypeptidases Carboxypolypeptidases (Proenzyme)

(Active)

Polypeptides

Oligopeptides and dipeptides

(Carboxypolypeptidases cleave the polypeptide chain from the side of carboxylic group) (4)

Nucleases Nuclease Nucleic Acid (RNA/DNA)

Nucleotides

DIGESTION & ABSORPTION (5)

661

Amylopsin (α-amylase) Amylopsin Starch (amylose)

Maltose

(Boiled/unboiled)

(6)

Steapsin (pancreatic lipase)

Steapsin Fats

Fatty acids + Glycerol (3)

(1)

Intestinal Juice – 1500ml/day; pH = 8 - 9. •

The secretion of intestinal juice (Succus entericus) is stimulated by Enterocrinin hormone. The juice contains:

(1)

Enterokinase (or enteropeptidase) – It converts inactive trypsinogen into active trypsin (as described above).

(2)

Aminopolypeptidases Aminopolypeptidase Polypeptides

Oligopeptides + Dipeptides

(The aminopolypeptidases are different from carboxypolypeptidases, and cleave the polypeptide chain from the side of amino group.) (3)

Dipeptidases

Dipeptidase Dipeptides

Amino Acids (2)

(The term Erypsin is used for both aminopolypeptidases and dipeptidases. Thus erypsin can digest polypeptides into amino acids.) (4)

Nucleotidases Nucleotidase Nucleotides

(5)

Nucleosides + Phosphoric acid

Nucleosidases -

Nucleosidase Nucleosides

Nitrogenous bases + Sugar (Pentose)

(6)

Lipase - It is secreted in small amounts and converts fats into fatty acids and glycerol.

(7)

Maltase -

Maltase Maltose

Glucose + Glucose

(Diasaccharide)

(two molecules of monosaccharides)

662

BIOLOGY Connecting Concepts

(8)

Lactase-

Lactase

 The enzyme lactase is absent in certain persons and they can not digest milk sugar. They, however, can take curd in which lactose is converted into lactic acid by bacterial enzymes. Such persons, however, have no problem in digesting milk protein, casein.

Lactose

Glucose + Galactose

(Diasaccharide)

(two molecules of monosaccharides)

(Lactose, the least sweetest sugar, is present only in the milk.) ( (Galactocemia is a congenital mental disorder due to excess of galactose. The children having such disorder are advised to take milk free diet.) (9)

Sucrase (invertase) Sucrase

Sucrose

Glucose + fructose (two mol. of monosaccharides)

Sucrose is cane sugar or table sugar and is also known as invert sugar ((Remember that Fructose is the sweetest sugar in nature). In small intestine the major part of digestion occurs in duodenum and the digested, simple substances are absorbed in the region of jejunum and ileum.

Connecting Concepts 1. Differentiate between : (i) Carboxypolypeptidases and Aminopolypeptidases. (ii) Lactase and Lactose (iii) Trypsin and Pepsin (iv) Secretin and CCK. (v) Nucleosidases and Nucleotidases (vi) Micelles and Chylomicrons (vii) Bolus and chyme (viii) Active transport and facilitated transport (ix) Gastro-oesophageal and ileo-caecal valve

Absorption of Food •

Maximum of the digestied food material including water is absorbed in the ileum part of small intestine.

•

The presence of villi/microvilli in small intestine increases the absorptive surface area by 600-times.

•

Water and water soluble products are absorbed by blood capillary-network of villi while fat soluble substances (insoluble in water) are absorbed by lymph vessels. Water 6. Fatty acids Minerals/salts 7. Glycerol Absorbed in Absorbed in Water soluble vitamin lymph-vessels Blood capillaries 8. Monoglycerides Amino acids 9. Fat soluble vitamins Monosaccharides

1. 2. 3. 4. 5.

}

}

•

The fructose, a hydrophilic sugar, is absorbed by facilitated diffusion using transporter protein, while glucose is absorbed by active transport.

•

The fat soluble vitamins and most of the digestive end products of fat, being hydrophobic, are not absorbed into the blood capillaries but are mixed with bile salts and phospholipids to form Micelles (The fatty acids containing less than 10-12 carbon atoms can, however, pass directly through mucosal cells into the portal blood as free or unesterified fatty acids)

•

The other fat products, like fatty acids (>12 C atoms), glycerol, sterols and fat soluble vitamins are absorbed from micelles, by facilitated diffusion, into enterocytes.

•

Within enterocytes the fats are resynthesized to form protein coated particles, called Chylomicrons. These chylomicrons pass into lacteals (lymph vessels of villi). This is because the permeability of lymph vessels is greater than the permeability of blood vessels.

•

Due to absorption of chylomicrons in the lymph the fluid becomes white and is called Chyle.

•

About 90-95% of bile salts are absorbed from ileum part of small intestine.

6.

Caecum and Vermiform appendix –

•

Both structures are meant for cellulose fermentation in rabbit and rat etc. In human these structures are vestigial as human can not digest cellulose.

•

Both structures in human, however, contain lymph nodules and help in lymphocytes production.

DIGESTION & ABSORPTION 7.

Colon -

•

It includes Ascending colon, Transverse colon (The largest part of colon), Descending colon and Pelvic colon.

•

It contains 3-bands of longitudinal muscles, called Tenia Coli which form pockets/pouches, called Haustra for water & mineral absorption.

•

About 1-2 litre of fluid reaches colon.

•

No digestive enzyme is secreted from colon.

•

E. coli bacteria survive on undigestive waste of colon and produce vitamin B1, B2, B12, folic acid and vitamin-K for human use.

8.

Rectum -

•

It stores undigested food. The solid waste contains ~30% bacteria, ~30% dry constituents of undigested food. The undigested food contains 10-20% fat and very low protein content.

•

This waste is removed from the body by egestion or defaecation through anal opening.

663

664

BIOLOGY

EXERCISE - 1 | NCERT BASED QUESTIONS 1. 2. 3.

4. 5.

6.

7.

8. 9.

10. 11. 12.

The digestion of butter begins with (1) Saliva (2) Gastric juice (3) Pancreatic juice (4) Intestinal juice Protein coated small fat globules for absorption are called (1) Chylomicrons (2) Micelles (3) Lacteals (4) None of these Glucose, some amino acids and sodium are absorbed in to blood by (1) Simple diffusion (2) Active transport (3) Facilitated transport (4) The statement is incorrect since they are absorbed in lymph and not in blood The disaccharidases are secreted with (1) Saliva (2) Gastric juice (3) Intestinal juice (4) Pancreatic juice The utilization of absorbed food substances by tissues is called (1) Deglutition (2) Assimilation (3) Emulsification (4) Constipation The hydrolytic action of the following enzyme produces pentose sugar (1) Amylase (2) Sucrase (3) Nucleotidase (4) None of these Succus entericus is a term used for (1) The junction of ileum and colon (2) Inflammation of intestine (3) Vermiform appendix (4) Digestive juice of intestine Gastric juice does not contain (1) Lipase (2) Rennin (3) Protease (4) Amylase Enterokinase is (1) A hormone that prevents the secreton of gastric juice (2) An enzyme that activates the enzymes of pancreatic juice (3) An enzyme that activates the proteolytic enzymes of succus entericus (4) A hormone that prevents the secretion of pancreatic juice Bile juice does not contain (1) Bilirubin (2) Phospholipids (3) Lipases (4) Cholesterol Hydrolysis by following enzyme produces only glucose (1) Amylase (2) Sucrase (3) Lactase (4) Maltase Which of the following is not a proteolytic enzyme (1) Chymotrypsin (2) Rennin (3) Steapsin (4) All of these

13.

14.

15.

16.

17.

18.

19.

20.

21.

The common bile duct in humam is formed by the joining of (1) Pancreatic duct and bile duct (2) Cystic duct and hepatic duct (3) Cystic duct and pancreatic duct (4) Hepatic duct and pancreatic duct Carbohydrases are missing from (1) Intestinal juice (2) Pancreatic juice (3) Gastric juice (4) Saliva The sphincter of Oddi is present between (1) Oesophagus and cardiac stomach (2) Pyloric stomach and duodenum (3) Hepatic duct and cystic duct (4) Hepatopancreatic duct and duodenum Mark the incorrect statement in the followings (1) Brunner’s glands are submucosal (2) Irregular folds of gastric mucosa are rugae (3) Glisson’s capsule is the connective tissue sheath of hepatic lobule (4) Mosothelium or serosa lies in close proximity of the circular layer of tunica muscularis The tongue is attached to the floor of oral cavity by (1) Papillae (2) Frenulum (3) Uvula (4) Gullet How many types of tissues are present in stomach (1) Oral mucosa (2) Gastric mucosa (3) Three types only (4) All four types The absorption of water alcohol and simple sugars occurs in (1) Oral mucosa (2) Gastric mucosa (3) Mucosa of ileum only (4) Mucosa If for some reason the parietal cells of the gut epithelium become partially non-funcitonal, what is likely to happen? (1) The pancreatic enzymes and specially the trypsin and lipase will not work efficiently (2) The pH of stomach will fall abruptly (3) Steapsin will be more effective (4) Proteins will not be adequately hydrolysed by pepsin into proteoses and peptones Jaundice is a disorder of (1) Excretory system (2) Skin and eyes (3) Digestive system (4) Circulatory system

DIGESTION & ABSORPTION

665

EXERCISE - 2 | Window to Competitive Exams 1.

2.

3.

4.

5.

6.

7.

8.

9.

10.

11.

Milk protein is acted upon by a gastric enzyme in infant mammals named [Orissa ‘95] (1) Rennin (2) Caesinogen (3) Pepsinogen (4) Pepsin A dental disease characterized by mottlilng of teeth due to ingredient in drinking water, namely (1) Fluorine (2) Chlorine [CBSE ‘95] (3) Boron (4) Mercury Gall baldder is attached to liver in the region of [Punjab ‘95] (1) Quadrate lobe (2) Caudate lobe (3) Right lobe (4) Left lobe The hardest constituent of tooth is [DPMT ‘87; MP ‘95] (1) Bone (2) Dentine (3) Enamel (4) Pulp Hydrochloric acid in the stomach is secreted by [DPMT ‘96] (1) Chief cells (2) Zymogen cells (3) Parietal cells (4) None of these The pH of succus entericus is [MP ‘96] (1) 7.6 (2) 6.6 (3) 5.6 (4) 2.0 The source of Cholecystokinin is [RPMT ‘96] (1) Gall bladder (2) Liver (3) Duodenum (4) Ileium What will happen if bile duct gets choked ? (1) Faeces become dry [DPMT ‘96] (2) Acidic chyme will not be neutralized (3) There will be little digestion in intestine (4) Little absorption of fat will occur. Choose the correct pair [CBSE ‘96] (1) Casein – Rennin (2) Protein – Amylase (3) Carbohydrate – Lipase (4) Lactose - Maltase The protein deficiency disease is known as [AIIMS ‘96] (1) Scurvy (2) Addison’s disease (3) Kwashiorkar (4) Pellagra Enterokinase in a/an [BHU ‘97] (1) Pancreatic hormone (2) intestinal enzyme (3) Pancreatic enzyme (4) content of bile

12.

13.

14.

15.

16.

17.

18.

19.

20.

21.

22.

Cystic duct comes out from the [PCS ‘97] (1) Gallbladder (2) Hepatic lobes (3) Pancreatic libes (4) Kidney Which of the following control the amount of enzymes in pancreatic juice? [CPMT ‘97] (1) Cholecystokinin (2) Secretin (3) Pancreozymin (4) Gastrin Enterokinase is [KCET ‘95; BHU ‘97] (1) Pancreatic hormone (2) Intestinal hormone (3) Component of pancreatic juice (4) Component of intestinal juice. Which enzyme initiates protein digestion ? (1) Pepsin (2) Trypsin [MP ‘97] (3) Aminopeptidase (4) Carboxypeptidase Enzyme which does not directly act upon food substrate is [KCET ‘97] (1) Trypsin (2) Lipase (3) Enterokinase (4) Amylopsin Lathyrism due to consumption of khesri dal is characterized by [CBSE ‘98] (1) Skeletal deformation and thinning of collagen fibres (2) Skeletal abnormalities, diabetes mellitus and reproductive failure (3) Retarded growth, precocious puberty and renal dysfunction (4) Cardiovascular abnormalities mental retardation and delayed puberty. Layer of cells that secrete enamel of tooth is [CBSE ‘98] (1) Osteoblast (2) Ameloblast (3) Odontoblast (4) Dentoblast Ptyalin is an enzyme present in [AFMC ‘87; MP ‘99] (1) Gastric Juice (2) Pancreatic juice (3) Intestinal Juice (4) Saliva Water is largely absorbed in [CPMT ‘99] (1) Stomach (2) Oesophagus (3) Small intestine (4) Colon Trypsinogen is produced by [BHU ‘99] (1) Liver (2) Duodenum (3) Stomach (4) Pancreas Liver in our body stores [AIIMS ‘99] (1) vitamin B12 (2) vitamin A (3) vitamin D (4) all of these

666 23.

24.

25.

26.

27.

28.

29.

30.

31.

32.

33.

BIOLOGY Chylomicrons are [CPMT ‘99] (1) undigested proteins (2) undigested carbohydrates (3) fat droplets coated with phospholipids (4) fat droplets coated with glycerol and proteins Most of the fat digestion occurs in [CBSE ‘93; Haryana 2000] (1) Rectum (2) Stomach (3) Colon (4) Small intestine Enterokinase takes part in conversion of [CBSE ‘95; AFMC ‘96; CPMT ‘99; BHU 2000; Kerala 2000] (1) Pepsinogen to pepsin (2) Trypsinogen to trypsin (3) Protein into polypeptides (4) Caseinogen into casein Gaucher’s disease is related to [Kerala 2000] (1) Abnormal fat metabolism (2) Vitamin deficiency (3) Disturbed carbohydrate metabolilsm (4) Abnormal protein metabolism What is common among amylase, renin and trypsin [CBSE ‘97; Punjab ‘99; CPMT 2000] (1) All are proteins (2) Proteolytic enzymes (3) Produced in stomach (4) Act at pH lower than 7. Which chamber of ruminant stomach has gastric juice (HCI + Pepsin) [CET Chd. 2000] (1) Qmasum (2) Abomasum (3) Rumen (4) Reticulum In case of taking food rich in lime juice, the action of ptyalin on starch is [AIIMS 2000] (1) Enhanced (2) Reduced (3) Unaffected (4) Stopped Feeding on dead and decaying organisms represent what type of nutrition? [CPMT 2000] (1) Autotrophic (2) Holozoic (3) Saprotrophic (4) Parasitic Lactase is found in: [MP 2000] (1) saliva (2) bile (3) Pancreatic juice (4) intestinal juice Sodium taurocholate aids in [EAMCET 2000] (1) absorption (2) defecation (3) assimilation (4) emulsification Bilirubin and biliverdin are found in [MP ‘01] (1) Blood (2) Bile (3) Pancreatic juice (4) Saliva

34.

35.

36.

37.

38.

39.

40.

41.

42.

43.

44.

45.

Brunner’s glands are found in [CPMT ‘88, 96; CBSE ‘92; MP ‘98; Kerala ‘01] (1) Submucosa of stomach (2) Wall of rectum (3) Submucosa of duodenum (4) Mucosa of ileum In ruminants bacterial action occurs in [DPMT ‘01] (1) Reticulum (2) Omasum (3) Abomasum (4) Rumen Fat absorbed from gut is transported in blood as [Kerala ‘01] (1) Micelles (2) Liposomes (3) Phagocytes (4) Chylomicrons Digestion of carbohydrates occurs in [UA ‘01] (1) Buccal cavity (2) Stomach (3) Intestine (4) All the above Marasmus is caused by [MP ‘01] (1) obesity (2) dwarfism (3) prolonged starvation (4) deficiency of vitamin Enzyme trypsin is secreted by [AFMC ‘87, ‘03; Karala ‘02] (1) Duodenum (2) Liver (3) Pancreas (4) Stomach Wisdom teeth in man are [CPMT ‘02] (1) Incisors (2) First premolar (3) Last molars (4) All In whose milk percentage of lactose is highest? [CPMT ‘02] (1) Human mother (2) Cow (3) She buffalo (4) She goat Identify the correct set which shows the name of the enzymes from where it is secreted and substrate upon which it acts [Orissa ‘02] (1) Pepsin – Stomach wall – Caesin (2) Ptyalin – Intestine – Maltose (3) Chymotypsin – Salivary gland –Lactose (4) Ptyalin – Pancreas – Lipid An enzyme which brings about conversion of starch into maltose is [PCS ‘02] (1) catalase (2) maltase (3) invertase (4) diastase Pulp cavity of a tooth is lined by [CPMT ‘02] (1) Ameloblasts (2) Chondroblasts (3) Osteoblasts (4) Odontoblasts HCl of gastric juice [KCET ‘02] (1) Inactivates ptyalin and activates pepsin (2) Activates ptyalin and inactivates pepsin (3) Inactivates both ptyalin and pepsin (4) Activates both ptyalin and pepsin.

DIGESTION & ABSORPTION 46.

47.

48.

49.

50.

51.

52.

53.

54.

55.

56.

Curdling of milk in small intestine would occur with the help of [AIIMS ‘02] (1) Rennin (2) Erypsin (3) Chymotrypsin (4) Trypsin Rennin acts on milk protein and changes [JIPMER ‘02] (1) Caesinogen into caesin (2) Caesin into paracaesin (3) Caseinogen into paracaesin (4) Paracaesin into caesinogen Meckel’s diverticulum is found in [JIPMER ‘02] (1) rectum (2) ileum (3) pylorus (4) appendix Function of galbladder is [RPMT ‘02] (1) storage of bile (2) formation of enzymes (3) synthesis of bile (4) formation of bile salts If the chyme of a person who had orally consumed only starch as food is analysed before it enters the duodenum, it will show the presence of [KCET ‘02] (1) maltose and glucose (2) dextrin and maltose (3) starch, dextrin and maltose (4) starch, dextrin and glucose Secretin stimulates production of [CBSE ‘90; CPMT ‘90; BHU 2000; MP ‘02] (1) Saliva (2) Gastric juice (3) Bile (4) Pancreatic juice A person is passing gray white faecal matter, What is not functioning properly in the body ? (1) Kidney (2) Liver [CBSE ‘02] (3) Spleen (4) Pancreas The cells of pancreas are not autodigtested by their enzymes as [IPU ‘02] (1) Cells are covered by mucous (2) Enzymes are produced only when required (3) Enzymes do not have coenzymes (4) Enzymes are secreted in inactive form From origin point of view the Liver is [Vellore ‘02] (1) Ectodermal (2) Endodermal (3) Mesodermal (4) Both (1) and (2) Continued consumption of a diet rich in butter, red meat and eggs for a long period may lead to (1) vitamin toxicity [AIIMS ‘03] (2) kidney stones (3) hyperchloesterolemia (4) urine laden with ketone bodies DNase and RNase are enzymes secreted by [BHU ‘03] (1) pancreas (2) stomach (3) gali bladder (4) intestines

667 57.

58.

59.

60.

61.

62.

63.

64.

65.

66.

67.

Carnassial teeth are modified for [BVP ‘03] (1) Cutting (2) Tearing (3) Grinding (4) Crushing One of the cyanobacteria rich in vitamin B12 carotenoids, iron and other essential nutrients, now being used in modern medicines as nutritional supplements, is [AMU ‘03] (1) Nostoc (2) Spirulina (3) Anacystis (4) Anabaena Excessive simulation of vagus nerve in humans may lead to [AMU ‘03] (1) hoarse voice (2) peptic ulcers (3) efficient digestion of proteins (4) irregular contractions of diaphragm Fats absorbed into lecteals as chylomicrons are [AMU ‘03] (1) glycerol (2) fatty acids (3) triglycerides (4) monoglycerides Fermentation chamber of herbivores is [Jharkhand ‘03] (1) caecum (2) liver (3) gall bladder (4) pancreas People recoverting from long illness are often advised to include the alga Spirulina in their diet because is [AIIMS ‘03] (1) is rich in proteins (2) has antibiotic properties (3) makes the food easy to digest (4) restores the intestinal microflora Bile aids in digestion and absorption of fats because it contains [AFMC ‘85; MAHE ‘05] (1) Lipase (2) Bile salts (3) Bile pigments (4) All the above During prolonged fasting [CPMT ‘05] (1) First fats are used up, followed by carbohydrates from liver and muscles and proteins in the end (2) First carbohydrates are used up, followed by fat and proteins towards end (3) First lipids, followed by proteins and carbohydrates towards end (4) None of the above Epithelial cells of the intestine involved in food absorption have on their surface: [CBSE ‘05] (1) Pinocytic vesicles (2) Microvilli (3) Zymogen granules (4) Phagocytic vesicles End product of protein digestion is [Haryana ‘05] (1) sugar (2) amino acid (3) nucleotide (4) Ammonia Part of alimentary canal meant for reabsorption of the maximum H2O is [CPMT ‘05] (1) Small intestine (2) large intestine (3) rectum (4) colon

668 68.

69.

70.

BIOLOGY Salivary amylase is also known as [MAHE ‘05] (1) ptyalin (2) gastrin (3) glyoxylase (4) pepsin Enzyme rennin used in digestion, is secreted from [BCECE ‘05] (1) intestine (2) stomach (3) liver (4) pancreas Which one of the following four secretions is correctly matched with its source, target and nature of action ? [AIIMS ‘05] Secretion

71.

72.

73.

74.

75.

76.

77.

Source

Target

78.

[JK ‘05] (1) sporozoic nutrition (2) holozoic nutrition (3) parasitic nutrition (4) saprophytic nutrition 79.

80.

Action

(1)

Gastrin

Stomach lining

Oxyntic cells

Production of HCl

(2)

Inhibin

Sertoli cells

Hypothalamus

inhibition of secretion of ganadotropin releasing hormone

(3)

Enterokinase

Duodenum

Gall bladder

Release of bile juice

(4)

Atrial Natriuretic factor (ANF)

Sinu atrial node(SAN) M-cells of Atria

Juxtaglomerular apparatus (JGA)

Inhibition of release of renin

Kwashiorkar is caused due to deficiency of [MAHE ‘05] (1) calories (2) hormone (3) zwitter ion (4) essential amino acid Which enzyme shows greatest substrate specificity? [CPMT ‘05] (1) nuclease (2) trypsin (3) sucrase (4) pepsin Essentially the word ‘digestion’ means [CPMT ‘05] (1) burning of food (2) oxidation of food (3) hydrolysis of food (4) breakdown of bood Which of the following is called as a detritivore? [KCET ‘05] (1) an animal feeding on decaying organic matter (2) an animal feeding on a plant (3) a plant feeding on an animal (4) an animal feeding on another animal. How many human teeth appear twice during the life span of an individual? [KCET ‘05] (1) 16 (2) 32 (3) 22 (4) 20 Animals consuming only plant materials are referred as [JK ‘05] (1) herbivores (2) carnivores (3) omnivores (4) insectivores A substance that prevents or delays oxidation is [JK ‘05] (1) bactericidal (2) hormone (3) antioxidant (4) enzyme

Engulfing of food either in solid or liquid is called

81.

Both the crown and root of a tooth is covered by a layer of bony hard substance. It is called [JK ‘05] (1) enamel

(2) dentine

(3) bony socket

(4) cementum [JK ‘05]

Substrate for the amylase enzyme is (1) nucleic acids

(2) protein

(3) starch

(4) fat [Orissa ‘05]

Maltase coverts (1) maltose to glucose at pH greater than 7 (2) maltose to glucose at pH lesser than 7.0 (3) maltose to alcohol (4) starch to maltose at pH higher than 7.0

82.

Reverse flow of food into the stomach of Rabbit is prevented by [EAMCET ‘05] (1) Pyloric sphincter (2) Ileo-caecal valve (3) Cardiac sphincter (4) Uvula

83.

84.

Peyer’s patches produce

[CPMT ‘90, ‘06]

(1) Enterokinase

(2) Amylase

(3) Trypsin

(4) Lymphocytes [CPMT ‘96, ‘06]

Succus entericus is

(1) Swollen area between ileum and rectum (2) Intestinal juice (3) Any swelling in gut (4) Vermiform appendix 85.

Chylomicrons are concerned with

[CPMT’06]

(1) digestion of fats (2) absorption of fats (3) digestion of proteins (4) absorption of proteins 86.

Dental formula of man is [Kerala ‘02; BCECE ‘05; HPMT ‘06]

87.

(1) 1223/1223

(2) 2132/2132

(3) 2123/2123

(4) 2213/2213

The main function of lacteals in the villi of human-small intestine is the absorption of (1) amino acids and glucose (2) glucose and vitamins (3) water and mineral salts (4) fatty acids and glycerol

[KCET ‘05, ‘06]

DIGESTION & ABSORPTION 88.

669

The following is a scheme showing the fate of carbohydrate during digestion in the human alimentary canal. Identify the enzymes acting at stages indicated as A, B, C and D. Choose the correct option from those given. [KCET’06] Starch

98.

A

89.

90.

91.

92.

93.

94.

95.

96.

In human the digestion of food is completed in the [CPMT’06] (1) mouth

(2) stomach

(3) small intestine

(4) large intestine [CPMT’06]

Bile pigments help in (1) digestion of fats

Lactose

Maltose

sucrose

B

C

D

Galactose

Glucose

Fructose

(1) A= amylase, B = maltase, C = lactase, D = invertase (2) A = amylase, B = maltase, C= invertase, D= lactase (3) A = amylase, B = invertase, C = maltase, D= lactase (4) A = amylase, B = lactase, C = maltase, D = invertases Which of the following is correct chronological order for enzyme activity of some enzymes taking part in protein digestion? [GCET’06] pep sin → tryp sin → peptidase (1) (2)

97.

pep sin → peptidase → tryp sin

(3) tryp sin → pep sin → peptidase (4) peptidase → tryp sin → pep sin The digestive enzyme that is not found in human pancreatic juice is [Kerala’06] (1) nucleotidase (2) nuclease (3) trypsin (4) lipase Dentine is secreted by [Orissa’06] (1) odontoblast (2) ameloblast (3) osteoblast (4) chondroblast Food bolus after passing through alkaline medium is [Orissa’06] (1) chyle (2) chyme (3) chylomicron (4) fat body Alimentary canal of herbivorous differ from carnivorous having [Orissa’06] (1) short alimentary canal (2) long alimentary canal (3) wide alimentary canal (4) thin alimentary canal pH os saliva is [Orissa’06] (1) 6.5 (2) 8 (3) 7 (4) 9.5 Yellow colour of faeces is due to [Orissa’06] (1) bile secretion (2) green colour of bile juice (3) degradation product of haemoglobin (4) excessive diet of turmeric Crypts of lieberkuhn are present in [CPMT’06] (1) intestine (2) stomach (3) oesophagus (4) all of these

(2) absorption of fats (3) both absorption & digestion of fats (4) excretion 99.

Lysozyme, that is present in perspiration, saliva and tears, destroys. [CBSE’07] (1) most virus-infected cells (2) certain fungi (3) certain types of bacteria (4) all viruses

100. Which one of the following is the correct matching of the site of action on the given substrate, the enzyme acting upon it and the end product? [CBSE’08] Lipase

(1) Stomach : Fats  → micelles (2) D u o d e n u m : T r i g l y c e r i d e s monoglycerides

Trypsin

 →

∝Amylase

→ \ Disaccharide (3) Small intenstine : Starch  (Maltose) pepsin

(4) Small intestine : Proteins  → Amino acid 101. What will happen if the secretion of parietal cells of gastric glands is blocked with an inhinbitor? [CBSE’08] (1) Enterokinase will not be released from the duodenal mucosa and so trypsinogen is not converted to trypsin (2) Gastric juice will be deficient in chymosin (3) Gastric juice will be deficient in pepsinogen (4) In the absence of HCl secretion, inactive pepsinogen is not converted into the active enzyme pepsin. 102. When breast feeding is replaced by less nutritive food low in proteins and calories; the infants below the age of one year are likely to suffer from : [CBSE’09] (1) Pellagra

(2) Marasmus

(3) Rickets

(4) Kwashiorkor

103. Which one of the following pairs of food components in humans reaches the stomach totally undigested : (1) Starch and cellulose [CBSE’09] (2) Protein and starch (3) Starch and fat (4) Fat and cellulose

670

BIOLOGY

104. Which one of the following statements is true regarding digestion and absorption of food in humans [CBSE’09] (1) About 60% of starch is hydrolysed by salivary amylase in our mouth. (2) Oxyntic cells in our stomach secrete the proenzyme pepsinogen. (3) Fructose and amino acids are absorbed through intenstinal mucosa with the help of carrier ions like Na+ (4) Chylomicrons are small lipoprotein particles that are transported from intestine into blood capillaries. 105. A young infant may be feeding entirely on mother’s milk which is white in colour but the stools which the infant passes out is quite yellowish. What is this yellow colour due to ? [CBSE’09] (1) Pancreatic juice poured into duodenum (2) Intestinal juice (3) Bile pigments passed through bile juice (4) Undigested milk protein casein 106. Carrier ions like Na+ facilitate the absorpton of substances like : [CBSE’10] (1) fructose and some amino acids (2) amino acids and glucose (3) glucose and fatty acids (4) fatty acids and glycerol 107. If for some reason our goblet cells are non-functional, this will adversely affect. [CBSE’ 10, Final] (1) smooth movement of food down the intestine. (2) Production of somatostain (3) secretion of sebum from the sebaceous glands (4) maturation of sperms. 108. If for some reason the parietal cells of the gut epithelium become partially non-functional, what is likely to happen? [CBSE’ 10, Final] (1) The pancreatic enzymes and specially the trypsin and lipase will not work efficiently (2) The pH of stomach will fall abruptly (3) Steapsin will be more effective (4) Proteins will not be adequately hydrolysed by pepsin into proteoses and peptones 109. Jaundice is a disorder of

[CBSE’ 10, Final]

(1) Excretory system (2) Skin and eyes (3) Digestive system (4) Circulatory system 110. Bile contribution to digestion is (1) Nucleic acid metabolism (2) Phagocytosis (3) Emulsification of dietary lipids (4) Carbohydrate digestion

[DPMT’ 10]

111. Which one of the following enzymes carries on the initial step in the digestion of milk in humans? [CBSE’ 11] (1) Trypsin (2) Pepsin (3) Rennin (4) Lipase 112. Which one of the following correctly represents the normal adult human dental formula? [CBSE’ 11, Final] (1) 2 ,1 ,2 ,3 /2 1 2 3 (2) 3 ,1 ,3 ,3 /3 1 3 3 (3) 3 ,1 ,3 ,1 /3 1 2 1 (4) 2 ,1 ,3 ,3 /2 1 2 3 113. One of the constituents of the pancreatic juice while poured into the duodenum in humans is [CBSE’ 11, Final] (1) Maltase (2) Enterokinase (3) Trypsinogen (4) Chymotrypsin 114. Aggregates of lymphoid tissue present in the distal portion of the small intestine are known as [DPMT’ 10,11] (1) Villi (2) Peyer’s patches (3) Rugae (4) Choroid plexus 115. Sphincter of Oddi guards [DPMT’ 11] (1) Hepato-pancreatic duct (2) Common bile duct (3) Pancreatic duct (4) Cystic duct 116. Anxiety and eating spicy food together in an otherwise normal human, may lead to [CBSE’ 12] (1) Diarrhoea (2) Vomiting (3) Indigestion (4) Jaundice 117. After surgical removal of an infected gall bladder, a person must be especially careful to restrict dietary intake of: (1) Starch (2) Protein [AMU’13] (3) Sugar (4) Fat 118. Ontogenetically liver and pancreas are: [AMU’13] (1) Ectodermal (2) Mesodermal (3) Endodermal (4) None of these 119. The initial step in the digestion of milk in human is carried out by [AIPMT’14] (1) Lipase (2) Trypsin (3) Rennin (4) Pepsin 120. Fructose is absorbed into the blood through mucosa cells of intestine by the process called: [AIPMT’14] (1) Active transport (2) Facilitated transport (3) Simple diffusion (4) Co- transport mechanism 121. Which of the following statements is not correct? [AIPMT’15] (1) Brunner’s glands are present in the submucosa of stomach and secrete pepsinogen (2) Goblet cells are present in the mucosa of intestine and secrete mucus (3) Oxyntic cells are present in the mucosa of stomach and secrete HCl (4) Acini are present in the pancreas and secrete carboxypeptidase

DIGESTION & ABSORPTION

671 [AIPMT’15]

122. Gastric juice of infants contains: (1) Maltase, pepsinogen, rennin (2) Nuclease, pepsinogen, lipase (3) Pepsinogen, lipase, rennin (4) Amylase, rennin, pepsinogen

123. The primary dentition in human differs from permanent dentition in not having one of the following types of teeth: [RE-TEST AIPMT’15] (1) Premolars

(2) Molars

(3) Incisors

(4) Canine

124. The enzyme that is not present in succus entericus, is: [RE-TEST AIPMT’15] (1) Nuclease

(2) Nucleosidase

(3) Lipase

(4) Maltase

125. Fat soluble vitamin is:

[UP CPMT’15]

(1) Pyridoxine

(2)

Ascorbic acid

(3) Tocopherol

(4) Thiamine

126. Emulsification of fats by bile juice takes place in: [UP CPMT’15] (1) Liver

(2) Stomach

(3) Oesophagus

(4) Duodenum

127. Vermiform appendix arises from: (1) Caecum

(2) Colon

(3) Rectum

(4) Ileum

128. The optimum pH for pepsin is: (1) 11

(2) 5- 6

(3) 1.6- 2.4

(4) 4- 7

[AMU’15]

[AMU’15]

129. Enzyme not present in pancreatic juice is: [AMU’15] (1) Amylase (2) Chymotrypsinogen (3) Lipase (4) Enterokinase 130. Which one of the following vitamin is not fat soluble? [AMU’15] (1) A (2) B (3) D (4) E 131. The deficiency of which of the following vitamin will cause xerophthalmia? [AMU’15] (1) A (2) B (3) C (4) K 132. The secretions of the brush border cells of the intestinal mucosa along with the secretion of Goblet cells constitute the: [KERALA’15] (1) Succus entericus (2) Chyme (3) Gastric juice (4) Chylomicrons 133. Choose the correct statement among the followings: [KERALA’15] (1) The intestinal mucosal epithelium has oxyntic cells (2) Ptylalin converts proteins into proteoses and peptones (3) Crypts of Lieberkuhn are seen between the bases of villi in the intestine (4) Sphincter of Oddi is present at the junction of oesophagus and cardiac stomach 134. Identify the correctly matched structure and its secretion: [KERALA’15] (1) Brunner’s gland- Salivary amylase (2) Intestinal mucosa- Insulin (3) Gall bladder- Bile (4) Salivary gland- Lysozyme

672

BIOLOGY

EXERCISE - 3 | Test Yourself 1.

2.

3.

4.

5.

6.

7.

8.

9.

10.

11.

In human gut, in order of secretion, the proteolytic enzymes are (1) Renin, trypsin and steapsin (2) Pepsin, trypsin and erepsin (3) Trypsin , steapsin and dipeptidase (4) None of these Protective principles of the food include (1) Vitamins and proteins (2) Minerals and proteins (3) Minerals, vitamins and water (4) Protein, carbohydrates and lipids Lysosomes have (1) Zymases (2) Hydrolases (3) Reductases (4) Cyto-oxidases Which enzyme helps the sanguivorous animals to digest the blood by hydrolyzing fibrinogen into fibrin (1) Thrombin (2) Pepsin (3) Prothrombin (4) Trypsin The digestion of cellulose occurs in large intestine in (1) Deer (2) Camel (3) Rabbit (4) All of these Cholecystectomy is the removal of (1) Pancreas (2) Gall bladder (3) Caecum (4) Appendix In glycolate pathway which enzyme degrades the H2O2 into H2O and O2 (1) Catalase (2) Aldolose (3) L-amylase (4) All Mark the true statement in the followings (1) Pepsin cannot digest casein (2) Trypsin can digest collagen (3) Pepsin cannot digest collagen (4) Chymotrypsin can digest casein The proximate principles of the food constitute (1) Carbohydrates, proteins and lipids (2) Minerals, water and vitamins (3) Proteins only (4) Roughage only Which of the followings digestive end product is not absorbed by the active process (1) Glucose (2) Amino acids (3) Fatty acids (4) Fructose Diglycerides on digestion give (1) One Fatty acid and one Glycerol (2) Two Fatty acid and one Glycerol (3) Two Glycerol and one Fatty acid (4) Two Glycerols only

12.

13.

14.

15.

16.

17.

18.

19.

20.

21.

22.

Enzymes in bile juice are (1) Peptidases (2) Amylases (3) Lipases (4) Absent Semi - digested food in intestine is called(1) Chyle (2) Chyme (3) Bolus (4) None of these Nucleosides are formed by the action of (1) Nucleases (2) Nucleosidases (3) Nucleotidases (4) Any of these Protein nature of enzyme was suggested by (1) T. Cech (2) Northrop and Sumner (3) Jacob and Monad (4) None Steapsin acts on (1) Peptide bonds (2) Glycosidic bonds (3) Ester bonds (4) Hydrogen bonds. What is true about ptyalin and amylopsin (1) Ptyalin is α- amylase while amylopsin is β-amylase (2) Ptyalin is β - amylase while amylopsin is α-amylase (3) Both ptyalin and amylopsin are α- amylases (4) Both ptyalin and amylopsin are β - amylases During swallowing the following does not occur (1) Soft palate moves away to open nostrils (2) Larynx rises up (3) Epiglottis closes off larynx (4) Tongue blocks the mouth Pancreatic juice rich in water and electrolytes but poor in enzymes is secreted in response to (1) Pancreozymin (2) Cholecystokinin (3) Secretin (4) Hepatokinin Which of the following substance is not absorbed in jejunum (1) Bile salt (2) Vitamin B12 (3) Fat soluble vitamin (4) Glucose In pancreatic juice, the followings are secreted in inactive forms as proenzymes (1) Trypsin, chymotrypsin & carboxypeptidases (2) Pepsin, trypsin and chymotrypsin (3) Trypsin only (4) Trypsin and chymotrypsin only The protein coated, water soluble fat globules are called (1) Chylomicrons (2) Micelles (3) Chyle (4) Monoglycerides

DIGESTION & ABSORPTION 23.

24.

25.

26.

27.

28.

29.

Which of the following animal is detritivorous? (1) Earthworm (2) Cockroach (3) Male mosquito (4) All of these Total gastrectomy may lead to (1) Haemolytic anaemia (2) Pernicious anaemia (3) Diarrhoea (4) Indigestion Which of the following enzyme is not present in pancreatic juice (1) Chymotrypsinogen (2) Steapsin (3) Nuclease (4) Enterokinase In Coprophagus mammals the cellulose is digested in (1) Rumen and Reticulum (2) Abomasum (3) Large intestine (4) Small intestine Which enzyme converts glucose to glucose-6 phosphate? (1) Phosphotase (2) Phosphorylase (3) Hexokinase (4) Isomerase Which enzyme is needed to digest the food reserve of castor seeds? (1) Protease (2) Lipase (3) Diastase (4) Amylase Bile is secreted by (1) Gall bladder (2) Sinusoids of liver (3) Kupffer cells (4) Hepatocytes

673 30.

31.

32.

33.

34.

If the bile- pancreatic duct is blocked, the following will not be affected (1) Digestion of proteins (2) Emulsification of fats (3) Level of blood glucose (4) Digestion of starch Which one of the followings is not related with the digestion of milk protein (1) Pepsin (2) Chymotrypsin (3) Rennin (4) Lactase An adult person consumes boiled potato. Mark the correct statement regarding the digestion of food compoments (1) Cellulose will be digested by cellulase (2) Starch will not be digested (3) Lactase will digest carbohydrates (4) DNA will be digested by pancreatic enzymes Which part of the prawn’s gut constitutes the intestine? (1) Fore gut and hepatopancreas (2) Mid gut only (3) Mid gut and hind gut (4) Hind gut only Hirudin (anticoagulant) is (1) Present in the blood of the mammals (2) Present in the blood of leech (3) Secreted by the mast cells of the human blood (4) Present in saliva of certain annelids

674

BIOLOGY

ANSWER KEY 1. 6. 11. 16. 21.

EXERCISE 1 : NCERT BASED QUESTIONS (2) 2. (1) 3. (2) 4. (3) 5. (4) 7. (4) 8. (4) 9. (2) 10. (4) 12. (3) 13. (2) 14. (3) 15. (4) 17. (2) 18. (4) 19. (2) 20. (3)

EXERCISE 2 : 1. (1) 2. 6. (1) 7. 11. (2) 12. 16. (3) 17. 21. (4) 22. 26. (1) 27. 31. (4) 32. 36. (4) 37. 41. (1) 42. 46. (3) 47. 51. (4) 52. 56. (1) 57. 61. (1) 62. 66. (2) 67. 71. (4) 72. 76. (1) 77. 81. (1) 82. 86. (3) 87. 91. (1) 92. 96. (1) 97. 101. (4) 102. 106. (1) 107. 111. (2) 112. 116. (3) 117 121. (1) 122. 126. (4) 127. 131. (1) 132.

1.

(2)

2. 3.

(3) (2)

WINDOW (1) 3. (3) 8. (1) 13. (1) 18. (4) 23. (1) 28. (4) 33. (4) 38. (1) 43. (2) 48. (2) 53. (2) 58. (1) 63. (1) 68. (3) 73. (3) 78. (4) 83. (4) 88. (1) 93. (3) 88. (2) 103. (1) 108. (1) 113. (4) 118 (3) 123. (1) 128. (1) 133.

(2) (3) (4) (4)

TO COMPETITIVE EXAMS (3) 4. (3) 5. (3) (4) 9. (1) 10. (3) (3) 14. (4) 15. (1) (2) 19. (4) 20. (3) (4) 24. (4) 25. (2) (2) 29. (2) 30. (3) (2) 34. (3) 35. (4) (3) 39. (3) 40. (3) (4) 44. (4) 45. (1) (2) 49. (1) 50. (3) (4) 54. (2) 55. (3) (2) 59. (2) 60. (3) (2) 64. (2) 65. (2) (1) 69. (2) 70. (4) (3) 74. (1) 75. (4) (2) 79. (2) 80. (3) (4) 84. (2) 85. (2) (4) 89. (1) 90. (1) (2) 94. (1) 95. (3) (4) 99. (3) 100. (3) (4) 104. (3) 105. (3) (4) 109. (3) 110. (3) (3) 114. (2) 115. (1) (3) 119 (3) 120 (2) (1) 124. (1) 125. (3) (3) 129. (4) 130. (2) (3) 134. (4)

EXERCISE 3 : TEST YOURSELF Pepsin is secreted from stomach, Trypsin from pancreas and Erypsin from ileum. Protein is the part of proximate principles.

4. 5.

(4) (3)

6. 8.

(2) (4)

9. 10.

(1) (4)

11. 12. 13.

(2) (4) (2)

14. 15. 16.

(3) (2) (3)

17. 18. 19. 22.

(3) (1) (3) (1)

23. 24. 25. 26. 27. 28.

(1) (2) (4) (3) (3) (2)

29. 30.

(4) (3)

31.

(4)

32.

(4)

33.

(3)

34.

(4)

Trypsin is present throughout the animal kingdom. In deer and camel the cellulose digestion occurs in rumen and reticulum of stomach. 7. (1) Milk protein can be digested by pepsin and chymotrypsin. Fructose is absorbed by rapid but passive process with carrier molecule. Neutral fat are triglycerides. Semi digested food in stomach or intestine is called chyme. Chyle is a term for lymph having fat Particles. Nucleotidases are secreted with Succus entericus. Ester bonds are present between alcohol and fatty acids (triglycerides). During swallowing the internal nostrils are closed. 20. (2) 21. (1) The Chylomicrons are formed inside enterocytes and are absorbed in lacteals. Earthworm feeds on decaying organic matter. Enterokinase is present in intestinal juice. In ruminants the cellulose is fermented in stomach. Hexokinase is an allosteric enzyme. Castor seeds have castor oil (fat) which is digested by Lipase. Kupffer cells are phagocytic in nature. The level of glucose will not be effective because hormones do not pass through ducts. Lactase digests sugar (Lactose) of milk (not protein). Lactase digests milk sugar which will not be present in potato. However, enzymes for nucleic acid digestion are present in pancreatic juice. The mid-gut is lined with endoderm but hindgut (rectum) is lined with ectoderm.

17

Chapter

Breathing and Exchange of Gases Breathing and Exchange of Gases While going through the chapter pay special attention to the following – Terms and Definitions – 1. Tidal volume 3. Vital capacity 5. Hypercapnia 7. Asphyxia 9. Byssinosis Laws and effects – 1. Bohr’s law 3. Chloride shift

2. 4. 6. 8. 10.

Inspiratory capacity Functional residual capacity Hering- Breuer reflex Emphysema p50- value

2.

Haldane’s law

At a Glance   

External Respiration



Respiratory System in Human

Respiration is a physiochemical process involving exchange of gases and oxidation of food material to release energy. It is a catabolic process and includes two parts: 1. External Respiration: It includes intake of oxygen and removal of carbon-di-oxide from the body. It is also known as ventilation or breathing.

O2 Respiratory organ CO 2 In aquatic and terrestrial animals it can be represented as: Environment

Water 2.

O2 Gills (ex. fishes); Atmosphere CO 2

O2 CO 2

Lungs

(ex. mammals)

Internal Respiration: It includes gaseous exchange between the cells and fluid medium and utilization of oxygen, and production of carbon-di-oxide, by the cells.

Survey of respiratory structures in animals

              

Differences – 1. Larynx and Syrinx 2. Carboxyhaemoglobin and Carbaminohaemoglobin 3. Bronchi and bronchioles 4. Oxygenation and Oxidation of haemoglobin Relationship 1. pH of blood with the shifting of oxyhaemoglobin dissociation curve 2. p 50 – value and affinity of haemoglobin with oxygen.

Internal Respiration



Nasal passage Pharynx Larynx

Trachea

Bronchi and Bronchioles Alveoli Lungs

Diaphragm Ribs

Breathing rate Factors affecting breathing rate Control of breathing Composition of air Air volumes Transportation of gases

Important terms and disorders of respiratory system

676

BIOLOGY

Survey of respiratory structures in animals

Connecting Concepts  The Lungs in birds are non-elastic and contain air sacs. The residual air in such cases is absent.



In Protozoans, Porifers, Coelenterates and Helminthes there are no specialized respiratory structures, and exchange of gases occurs through general body surface.



In Annelids respiration is either cutaneous (ex. Earthworm and Nereis) or branchial.



In Arthropods there are various type of respiratory structures like Gills (in crustaceans), book lungs (in arachnids) and tracheal tubes (in insects). In Prawn, the gills (8 pairs) are of 3 types : (i) Podobranchs-1 pair; (ii) Arthrobranch-2 pairs (iii) Pleurobranch-5 pairs. All the gills are phyllobranch type. In Cockroach there are three pairs of longitudinal tracheal tubes. Each lateral tube contains 10 spiracles (Total spiracles = 10 pairs).



In Molluscs the respiratory structure are mainly Gills.



In Echinoderms the gills, body wall, respiratory tree and Tube feet (primarily the locomotory structures) are the respiratory structures.



In Protochordates and Cyclostomes the respiratory structures are Gills.



In Fishes the Gills are the main respiratory structures but in lung fishes (Dipnoi) the Gills and Lungs both are well developed.



In Amphibians the respiratory structures are either Gills ((Branchial respiration) or Lungs ((Pulmonary respiration). In Frog the respiration is Cutaneous, Bucco-pharyngeal as well as Pulmonary.



In Reptiles birds and mammals the respiration is Pulmonary.

RESPIRATORY SYSTEM IN HUMAN In human the respiratory structures are Lungs which are endodermal in origin. The respiratory system contains following important components:

Nasal passage 

It contains hair for filtering out dust particles.



Bowman’s glands secrete mucus.



Turbinals (bones) warm up the air.



The sensory lining of nasal passage is called Schneiderian membrane.

Pharynx 

It is a common passage for gut and respiratory tract.



The openings of internal nostrils in pharynx are called Choane.



The opening between Pharynx and Larynx is called Glottis. It is closed by epiglottis during swallowing of food. However, the opening between Pharynx and Gut (Oesophagus) is different, and is called Gullet.



The lateral sides of Pharynx contain openings of Eustachian canals also.

BREATHING AND EXCHANGE OF GASES

677

Paranasal sinuses Respiratory center

Nasal cavity Nose hairs

Phamyx Epiglottis Larynx Trachea

Esophagus Left lung Pulmonary vessels

Right lung Bronchi

Ribs

Vocal cords

Heart

Thyroid

Intercostal muscles

Pleural membrane Diaphragm

Muscles attached to diaphragm (A)

Arytenoid (B)

Fig. 17.1 : (A) Respiratory system of Human, (B) Vocal cords in Larynx

Larynx 

It is commonly called voice box or sound box.



In birds the sound box is present at the base of trachea and is called Syrinx.



In human it contains 9 cartilages− three paired and three unpaired. The unpaired cartilages include Thyroid, Cricoid and Epiglottis while paired cartilages include Arytenoid, Corniculate and Cuneiform.



Thyroid cartilage is collar shaped, and in males forms Adam’s apple (In frog, the thyroid cartilage is absent).



Cricoid cartilage is ring shaped (complete).



The Arytenoid cartilage is pyramidal. The vocal cords (1-pair) are attached to this cartilage.



Thyroid, Cricoid and Arytenoid are Hyaline cartilages while Epiglottis is elastic cartilage.

Trachea 

It is commonly called wind pipe, and contains ‘C’ shaped rings of Hyaline cartilage which prevent its collapsing. These cartilaginous rings are dorsally incomplete.



Tracheal lining is of Pseudo-stratified Epithelium (For details please see Animal Tissues in chapter 7). (In frog the Trachea is reduced due to absence of neck; in giraffe it is very long; and in penguins it is paired.)

Gullet

Opening of Eustachian Tube Epiglottis Glottis Fig. 17.2 : Inner View (Diagrammatic) of Pharynx

678

BIOLOGY

Bronchi and Bronchioles 

Trachea divides into Bronchi (Sing. Bronchus) called principal Bronchi. These further divide into secondary bronchi and tertiary bronchi. The cartilaginous rings are present in all Bronchi.



Bronchi divides into Terminal Bronchioles which in turn divide into Respiratory Bronchioles. The Bronchioles do not have cartilaginous rings.



Respiratory Bronchioles divide into Alveolar ducts forming Alveolar sacs. Each Alveolar sac is surrounded by Alveoli.

Alveoli 

Inner lining of the alveoli is simple squamous epithelium. The number of Alveoli in both the lungs is 300 million (3x108). The exchange of gases occurs mainly through alveoli. Principal/ Main Bronchus

Cartilaginous Rings

Secondary Brochus

Blood Vessel

Tertiary Bronchus Terminal Bronchiole Respiratory Bronchiole

Alveolar sac Alveoli

Alveolar Duct

Alveolar Epithelium

Alveolar duct

Atrium

Endothelium Basement membrane

Fig. 17.3 : Bronchial Tree showing Alveoli and the Respiratory Membrane (in box)

Lungs 

Lungs in human are solid and spongy ((In Frog they are hollow), and are present in thoracic cavity.



Left lung has 2 −lobes while right lung has 3− lobes.



Each lung is surrounded by two membranes called pleura. The outer pleural membrane is parietal or somatic while inner pleural membrane is visceral or splanchnic in nature. The cavity between two pleura (pleural cavity) is filled with a fluid ((perilymph) which reduces friction during breathing.

Diaphragm 

It is a muscular partition between thorax and abdomen of all mammals.



It is dome shaped at rest.



It is responsible for 75% of breathing volume during quiet respiration.

Ribs 

Number of ribs in human is 12 pairs.



In between ribs the inter-costal muscles are present. These muscles have 2 sets i.e. External intercostal muscles and Internal inter-costal muscles. These muscles move the ribs during breathing.

BREATHING AND EXCHANGE OF GASES

679 Costal Cartilage

S T E

RIBS

R N U M

Internal Intercostal Muscles External Intercostal Muscles

Fig. 17.4 : Intercostal Muscles

The breathing process includes two phases: 1. Inspiration, 2. Expiration 1. Inspiration  It is an active process.  The External inter-costal muscles contract and the ribs move outward and upward to increase the volume of thoracic cavity.  The diaphragm-muscles contract and the shape of diaphragm changes from dome to flat. With the contraction, the lower surface of the lungs is also pulled downward.  Lungs expand and air is drawn into the lungs. The lungs in human, like other mammals, are negative (-ve) pressure type. In frog the lungs are positive (+ve) pressure type. 2. Expiration  Quiet expiration is a passive process.  The diaphragm becomes dome shaped again.  The external inter-costal muscles now relax. In forced expiration the Internal inter-costal muscles contract. This is an active process. The abdominal muscles also contract to decrease thoracic volume. The forced expiration is a voluntary process and is, therefore, controlled by Cerebrum. (For breathing in Frog, please refer ‘Frog’ in Chapter 7).

Connecting Concepts  The Negative pressure- lungs means that the pressure in the lungs is reduced and becomes lesser than the atmospheric pressure, due to which the air is drawn into the lungs. The Positive pressure- lungs means the pressure out side the lungs (eg. in bucco-pharynx of frog) increases and the air is forced into the lungs

Breathing Rate  

12−15 /min. In newly born child the breathing rate is ~ 40/min.

Factors affecting breathing rate 1. 2. 3. 4. 5. 6. 7.

Size − Breathing rate (BR) increases with decrease in size ( B.R. ∝ 1/size) Sex − B.R. is higher in males Altitudes − B.R. ∝ altitude. Exercise − B.R. ∝ exercise. Temperature − B.R. ∝ temperature. Pressure − B.R. ∝ 1/pressure. Carbon−di−oxide concentration − B.R. ∝ CO2 conc.

Breathing Control It is of 2-types : I. Nervous control, II. Chemical control The nervous control can be voluntary (through cerebral cortex) or Involuntary (through medulla oblongata or pons) I. Involuntary nervous control− 3 respiratory groups of neurons. (a) Dorsal respiratory group (DRG) − It is present in the dorsal part of the medulla oblongata and generates basic respiratory rhythm. The nervous signals from this group are transmitted to diaphragm, which is primary inspiratory muscle. (b) Ventral respiratory group −It is located in ventro-lateral side of the DRG in medulla oblongata. It does not play any role in basic respiratory rhythm and remains inactive during quiet breathing. When the requirement of oxygen is increased the signals from this part are transmitted to inspiratory and expiratory muscles for faster breathing.

Check Point 1. Fill in the blanks with suitable words/ statements. (i) ................... muscles contract to move the ribs ............... in inspiration. (ii) Basic respiratory rhythm is maintained by the neurons of ............... group. (iii) Breathing rate............... with the increase in body size. (iv) Left and the right lungs have ............... and ............... lobes respectively in human. (v) The number of alveoli in humanlungs is ............... . (vi) ...............connects middle ear to pharynx (vii) Trachea divides into right and left bronchi at ...............thoracic vertebra (viii) Breathing of air volume is estimated by ............... (ix) Function of respiratory rhythm is moderated by ............... (x) ............... glands secrete mucus in nasal passage.

680

BIOLOGY Hering−Breuer Reflex − Hering Breuer inflation reflex is an increase in the duration of expiration produced by steady lungs inflation due to stimulation of stretch receptors present in the walls of bronchi and bronchioles. When the lungs become overinflated (over-stretched), the signals from stretch receptors are transmitted to DRG, and then by feedback mechanism it switches off the inspiration, same occurs in pneumotaxic centre (see following acount). Hering Breuer deflation reflex is a decrease in duration of expiration produced by marked deflation of lungs. The stimuli in both cases are mediated by Vagus nerve. (c) Pneumotaxic centre− It is located dorsally in Pons Varolli. It is the switch off -point for breathing.

Connecting Concepts  In human, the Hering-Breuer inflation reflex is activated when tidal volume increases to more than 1500 ml. It is a protective device and prevents the excess inflation of lungs.

th

4 Ventricle Dorsal Respiratory Group Ventral Respiratory Group Fig. 17.5 : Medulla Oblongata Showing Respiratory Centres

II.

Chemical Control A rise in pCO2 or H+conc. of arterial blood, or a drop in pO2, increases the rate of respiration by stimulating the activity of neurons in medulla. The chemoreceptors are located mainly in aortic and carotid bodies. The aortic bodies are usually two and are present near the arch of systemic aorta. Each carotid body (total two) is situated near the bifurcation of carotid artery. These receptors are stimulated when the arterial pO2 is low (These receptors are not stimulated in anemia & CO-poisoning since in such conditions the amount of dissolved oxygen reaching receptors remains the same). Besides aortic and carotid bodies there are chemoreceptors in the medulla also. These receptors are simultated by CO2 that diffuses into CSF through blood -brain barrier. This CO2 is hydrated to form H2CO3 which dissociates to increase the concentration of H+, and the medullary receptors are sensitive to it. (More the CO2, more are the H+ ions produced). (Remember that breathing or ventilation rate is doubled when the concentration of oxygen decreases by 75%. However, in case of CO2, the increase of even 0.25% can double the breathing rate).

Composition of Air Dry air has following composition Gases N2 O2 CO2 Inert

Percentage 78% 21% 0.03–0.04% gases

Partial Pressure ~ 600 mm of Hg ~ 160 mm of Hg ~ 0.3 mm of Hg 0.9% –

AIR VOLUMES 1. 2. 3.

Tidal volume (TV) =500 ml The amount of air exchanged during each quiet (normal) breathing. Inspiratory reserve volume (IRV) or complementary air = 2.5 to 3 litre. It is the maximum amount of air which can be breathed in after tidal volume. Inspiratory capacity = 3 − 3.5 litre Maximum amount of air which can be breathed in or inspired Inspiratory capacity = TV + IRV

BREATHING AND EXCHANGE OF GASES 4.

681

Expiratory Reserve Volume (ERV) or Supplementary air = 1 to 1.2 litre The maximum amount of air which can be breathed out after tidal volume when inspiration is normal. Expiratory Capacity = 1.5 litre The total amount of air which can be breathed out or expired after normal inbreathing. Expiratory Capacity = TV + ERV

5.

6

Lung Volume (L)

5

4

Inspiratory reserve volume

Vital capacity

3 Total lung capacity 2 Tidal volume

Expiratory reserve volume

1 Residual volume 0 Time Fig. 17.6 : Respiratory air volumes

6.

7. 8.

9. 10.

11.

Vital capacity = 3.5 − 5 litre The maximum amount of air which can be breathed out after deepest inspiration. Vital capacity = TV + IRV + ERV Residual Volume = 1.5 litre The amount of air left in the lungs after breathing out vital capacity. Functional Residual Capacity = 2.5 litre The amount of air left in the lungs after normal expiration. Functional Residual Capacity = ERV + RV Total lungs capacity − 5 − 6 litre The maximum amount of air that can be filled in the lungs. Dead space air = 150 ml The amount of air present in trachea, bronchi and bronchioles, which is not used in respiration. Diffusing Capacity − The volume of gas that diffuses through the membrane per minute for a pressure difference of 1 mm of Hg. It is dependent on partial pressure and solubility of gases. CO2 > O2 > N2 (The diffusing capacity of CO2 is 20 times greater to that of O2). (Respiratory air volumes are measured with the help of Spirometer)

TRANSPORTATION OF GASES (a) 1. 2.  



Transportation of Oxygen Through Plasma (in dissolved form) = 2 − 3% Through RBCs (in combination with haemoglobin) = 97 − 98% 1 gm of haemoglobin combines with 1.34 ml of oxygen 100 ml of blood (having ~15 g of haemoglobin) will contain 20.1 ml. of oxygen bound to Hb at 100% saturation. (Since there is slight mixing of venous blood in the pulmonary capillaries, the haemoglobin in arterial blood is only 97% saturated, containing 19.8 ml of O2; 19.5 ml bound to Hb and 0.3 ml in soluble form). It is customary to write haemoglobin as Hb4, since 1 molecule of haemoglobin has 4 sub-units (each sub-unit having 1 haem and 1 polypeptide chain).

Check Point 1. Differentiate between : (i) The lungs of birds and lungs of human. (ii) Larynx and Syrinx. (iii) Respiratory structures of insects and crustaceans. (iv) External respiration and internal respiration. (v) Positive and negative pressurelungs. (vi) Residual capacity and functional residual capacity. (vii) Complementary air and supplementary air. (viii) Diffusing capacity of CO2 and O2

682

BIOLOGY 

Haemoglobin combines with oxygen to form oxyhaemoglobin. This process is called oxygenation and not oxidation as ferrous form of heam remains as ferrous. Hb 4 + 4O 2  → Hb 4 O8 1 mol. 4 mol.



1 molecule of haemoglobin when fully saturated (~95% saturation) carries 4 molecules of oxygen.



1 molecule of myoglobin (structurally similar to one of the four sub units of Haemoglobin) can carry only 1 molecule of oxygen.



During one round through the body about 25% of oxygen is dissociated from oxyhaemoglobin and about 70% of oxygen is still associated with haemoglobin in venous blood.



(Remember that 100 ml of arterial blood delivers 25% of O2, i.e ~ 5ml., to the tissues)



Oxidation of haemoglobin (in the presence of oxidizing agent) forms Methaemoglobin in which the ferrous form of iron changes into ferric form. Methaemoglobin is an abnormal form of haemoglobin and is incapable of carrying oxygen.

Oxyhaemoglobin dissociation curve− 

Saturation of haemoglobin plotted against the partial pressure of oxygen gives a Sigmoid (S- shaped) curve.



The partial pressure of oxygen at which 50% of haemoglobin gets saturated, is called p50 value. p50value ∝

1 affinity of haemoglobin for O2

In normal adults the p50 value is ~ 27 mm of Hg. In foetus since the affinity of haemoglobin is higher than that of adult the p50 value is lower and curve is on left hand side (see comparative figure).

100 97%

50

p 50 Value 27 100 Partial Pressure of Oxygen (pO2) Fig. 17.7 : Oxyhaemoglobin Dissociation Curve

Partial Pressure of Oxygen (pO2)

Arterial Blood ~100mm of Hg (at 97% saturation)

Venous Blood 40mm of Hg (at 70% to 75% saturation)

Shifting of oxyhaemoglobin dissociation curve In all the following conditions the dissociation curve (Sigmoid) shifts to right hand side and the affinity of heamoglobin for oxygen decreases to release or dissociate more oxygen to the tissues. 1. 2. 3.

When concentration of carbon−di−oxide increases (CO2, conc. ↑↑) When temperature increases (Temp. ↑)

When acidity increases or pH decreases (acidity ↑)

BREATHING AND EXCHANGE OF GASES

683

When altitude increases (altitude ↑). When amount of 2, 3 DPG (Diphosphoglycerldehyde or Biphosphoglyceraldehyde, BPG) increases in RBCs (2,3 DPG ↑). During exercise the following changes occur : (a) A large amount of heat is produced, hence temperature rises (b) Due to rapid metabolism there is lack of O2 and accumulation of CO2. (c) The pH decreases due to accumulation of lactic acid in muscles. All these changes shift the curve to right handside and hence there is increased unsaturation of haemoglobin. 20°C 37°C Foetal 42°C 4. 5.

Maternal

po2 (A)

po2 (B)

Fig. 17.8 : (A) Comparison of Oxyhaemoglobin Dissociation Curve in Foetal & Maternal Blood, (B) Effect of Change of Temperature on Oxyhaemoglobin dissociation curve

When conditions are opposite, the curve shifts to left hand side. (In foetus the haemoglobin ‘HbF’ has 2 –α chains and 2 ––γ-chains, the latter in place of β chain of adults. The γ-chain does not bind easily with 2, 3 DPG and this fascilitates the movement of O2 from maternal to foetal blood) Myoglobin has higher affinity for oxygen than haemoglobin has, and therefore, it unloads oxygen only when blood is almost fully deoxygenated (p50 value for Myoglobin is very low, i.e. ~5 mm of Hg). The O2 dissociation curve for Myoglobin is rectangular hyperbola. Bohr’s Effect When pH of the blood decreases (acidity increases) the p50 value increases and affinity of haemoglobin for oxygen decreases. This effect or law is called Bohr’s effect. [The total amount of O2, in ml. per decilitre (100 ml) in arterial blood is 19.8 (19.5 ml in combined form and 0.3 ml in dissolved form); where as in venous blood the amount of O2 is 15.2 (15.1 ml in combined form and 0.12 ml in dissolved form] (b) Transportation of CO2 (1) In dissolved form (mainly through plasma) = 5−10%. The solubility of CO2 in plasma is 20 times more than the solubility of oxygen. (2) In the form of Carbamino compounds (through RBCs) ~ 20%.  CO2 combines with reduced haemoglobin to form Carbamino haemoglobin or carbamino compound.  It is non−enzymatic and reversible reaction. (3) In the form of Bicarbonates (through RBCs and Plasma) = 70−80%.  The CO2 enters RBCs and binds with H2O in the presence of Carbonic anhydrase (enzyme) to form carbonic acid, which soon disintegrates into hydrogen ions (H+) and bicarbonate ions (HCO3–).  The H+ bind with HbO2 (oxyhaemoglobin) to reduce it as haemoglobinic acid (H. Hb) and release O2 to the tissues.

Connecting Concepts  The combination of carbon monoxide with haemoglobin is called carboxy haemoglobin. The affinity of carbon monoxide with haemoglobin is 200−250 times greater than that of oxygen. The Carboxyhaemoglobin is a stable compound and does not release oxygen to the tissues. If this compound is formed in the body due to inhalation of carbon monoxide then the oxygen starvation will occur, and this will cause coma and finally death.

684

BIOLOGY Now concentration of bicarbonate ions increases. Some of these bicarbonate ions bind with the K+ of RBCs to form KHCO3 but most of the others are released from RBCs into plasma. In plasma HCO3– combine with Na+ to form NaHCO3. The CO2 in the blood is carried through RBCs (as KHCO3) as well as plasma (as NaHCO3) Maximum CO2 is carried in plasma in the form of sodium bicarbonates (NaHCO3). To compensate the loss of HCO3– from RBC, or to maintain electroneutrality, the chloride ions diffuse from plasma into RBC. This is called chloride shift or Hamburger’s reaction.



Check Point 1. Write approximate- numerical value of the followings: (i) Oxygen in tidal volume. (ii) Partial pressure of CO2 in arterial and venous blood. (iii) Amount of oxygen carried out by 100 ml. of oxygenated blood. (iv) Normal breathing rate in human. (v) Amount of O2 dissociated in each round of blood through the body. (vi) Expiratory capacity (vii) Partial pressure of oxygen in deoxygenated blood (viii) Percentage of carbon di oxide carried in dissolved state through plasma

   

T I

P CO2

CO2 + H2O

HbO2 + H

S

H. Hb + O2

O2

H2CO3 +

+

S

U

C.A.

H

HCO–3

–

Cl

+

L

HCO3

–

A

NaHCO3

S

Na +

O2 HbO2 + H+

O2

U

H.Hb –

–

HCO3

E

+

N

HCO3 + H H2CO3 C.A.

–

Cl

M

H2O

CO2

G CO2

A RBC

L

+

S

RBC

sp

Venous Blood 46mm of Hg

In lungs, the oxyhaemoglobin is formed first to release H+ from H.Hb, which combine with HCO3– to form carbonic acid . In the presence of C.A. the CO2 is now released into lungs. Thus the whole process of bicarbonate formation is reversed. (100 ml of venous blood delivers about 4 ml of CO2 into the lungs.) [The amount of CO2, in ml per decilitre (100 ml), in arterial blood, is 49 (46.4 ml. in combined form and 2.6 ml in dissolved from; whereas in venous blood it is 52.7 (49.7 ml in combined form and 3.0 ml in dissolved form.)] Hypercapnia − It is retention of CO2 in the body. Initially it stimulates respiration, then causes depression of CNS and ultimately leads to coma and death. Haldane’s Effect - Deoxyhaemoglobin (Hb) binds with more H+ than oxyhaemoglobin (HbO2)does. The deoxyhaemoglobin, present in venous blood, thus, carries more CO2 than oxyhaemoglobin. This is called Haldane’s effect. (The oxyhaemoglobin on the other hand is acidic and releases more H+) Composition of inspiratory and expiratory air

ht

tp s:

//n ee

tm

ed

ic a

la

ca

de m

y.

bl

og



Arterial Blood ~400mm of Hg

ot

Partial Pressure of CO2 (pCO2)

.c

Connecting Concepts  Carbonic anhydrase (enzyme) is the fastest working enzyme in human body. It can hydrate 36 million molecules of CO2 per minute.

om

Fig. 17.9 : Schematic representation of chloride shift, and formation of carbamino compounds and bicarbonates in RBCs

Gases / vapours O2 CO2 H2O

Inspiratory Air (in %) 20.8 0.03 – 0.04 ~ 1.0

Expiratory Air (in %) 15.3 4.2 ~ 6.0

IMPORTANT TERMS AND DISORDERS OF RESPIRATORY SYSTEM 1. 2. 3. 4. 5.

Eupnea− It is normal breathing (rate 12−15 per minute) Hypopnea− Decrease in breathing rate (BR ↓) Hyperpnea− Increase in breathing rate (BR ↑) Dyspnea− Distressed breathing or breathing with difficulty. Hypoxia−Lack of oxygen at tissue level. This term is preferred over Anoxia.

BREATHING AND EXCHANGE OF GASES 6. 7.

8.

9. 10. 11. 12.

13.

14.

15.

16.

Anoxia− No oxygen at tissue level. Asphyxia− Suffocation ddue to lack of oxygen and retention of CO2. It is produced by occlusion of the air way, acute Hypercapnia and hypoxia developed together. Asphyxia = Hypoxia + Hypercapnia Cyanosis− Bluish or violet colouration of skin and the mucous membrane. This developes due to the presence of excessive amount of reduced haemoglobin or partially deoxygenated blood, or due to inadequate amount of oxygen in the blood. It develops at low temp. when carbonic anhydrase (enzyme) become inactive. Emphysema− Irreversible distension of the respiratory bronchioles, alveolar sacs and alveoli. The wall separating adjacent alveoli break down and air remains filled even after expiration. If develops mainly due to tobacco (cigarette) smoking. Asthma− It is an allergic disorder due to inflammation of bronchi and bronchioles and causes wheezing. The bronchioles constrict due to spasm of smooth muscles and expiration becomes difficult. Hay fever− It is an allergic disorder of nasal lining. It develops due to hypersensitivity of the lining to pollen grains or other foreign particles. There is an episode of sneezing that begins following allergy. Atelectasis or Respiratory Distress Syndrome’ (Hyaline Membrane disease)− It is inability of lungs to expand at birth. This is mainly due to the deficiency of surfactant. In normal cases the surfactant (a phospholipid, Lecithin) reduces tension at alveolar surface, which reduces the effort to expand the lungs at birth. Blue-Baby Syndrome− The child skin becomes bluish (violet). It can develop due to congenital disorder of blood vascular system, like – persistent truncus arteriosus or defect of ventricular septum. It can also develop due to formation of Methaemoglobin (It is oxidized form of haemoglobin. Remember, oxyhaemoglobin is oxygenated form of haemoglobin). Methaemoglobin is incapable of transporting oxygen. This abnormal haemoglobin is formed due to high nitrate-contamination (from fertilizers) in groundwater. Occupational lung diseases (Diseases of industrial workers)− The diseases due to inhalation of organic and inorganic pollutants is called Pneumoconiosis. It includes (a) Anthracosis (pneumoconiosis of coal workers)− It develops due to inhalation of coal-dust in coal-mine workers. There occurs deposition of fibrous tissue in the lungs causing bronchitis and emphysema. (b) Silicosis − It is due to long exposure to dust containing silicon compounds. Workers of glass industry, pottery, gold and copper mines develop progressive fibrosis in the liver. (c) Asbestosis− It is due to inhalation of asbestos−fibres which may result in cancer of pleura. (d) Byssinosis− It is due to inhalation of fibres of cotton, flax and hemp. (For pneumonia, tuberculosis (TB), bronchitis, common cold etc., please refer ‘Human health and diseases’.) Drowning− In 10% of the drowning cases there is suffocation, in water, and when the subject loses struggle and does not breath, there is laryngospasm and death results from asphysia without any water in the lungs. In other cases the glottis muscles relax and water enters the lungs. The fresh water is rapidly absorbed, diluting the plasma and causes haemolysis. Decompression Sickness− When a diver gradully ascends from a dive, the nitrogen, dissolved at high pressure under water, diffuses from the tissues into the lungs and no harmful effects are noticed; but if the ascent is rapid then N2 escapes from the tissues and blood, in the form of bubbles, causing decompression sickness. These bubbles cause severe pain in joints. In the blood, the bubbles obstruct the arteries to the brain, spinal cord or other parts causing paralysis, choking (bubbles in pulmonary artery), myocardial disorder (bubbles in coronary artery), respiratory failure or damage to spinal cord. The decompression sickness may also develop in atmospheric air by sudden change of altitude (e.g. rise from sea level to 8000 m.)

685

Check Point 1. Name the followings : (i) The maximum volume of air that can be breathed in. (ii) The instrument used for measuring respiratory air volumes. (iii) The shape of oxyhaemoglobin dissociation curve for Myoglobin. (iv) The form in which maximum CO2 is carried through plasma. (v) The shift of chloride ions from plasma to RBCs. (vi) Common term for hypoxia and hypercapnia (vii) Inflammation of bronchi and bronchioles due to allergy (viii) The centre that moderates the functions of the ‘respiratory rhythm centre’ (ix) The disease due to inhalation of coal dust (x) Combination of CO and haemoglobin

686

BIOLOGY

EXERCISE - 1 | NCERT BASED QUESTIONS 1.

2.

3.

4.

5.

Trachea divides at (1) 5th thoracic vertebra into right and left secondary bronchi (2) 7th thoracic vertebra into secondary bronchi (3) 5 th thoracic vertebra into right and left primary bronchi (4) 7th thoracic vertebra into primary bronchi Cartilagenous rings in respiratory passage are present in (1) Trachea only (2) Trachea and initial part of bronchi only (3) Trachea, bronchi and initial bronchioles only (4) Trachea, bronchi and all bronchioles Mark the correct statement (1) Tracheal rings are of hyaline cartilage (2) Dorsal side of thoracic chamber is formed by sternum (3) Expiration occurs when there is negative pressure in lungs (4) All of these Functional residual capacity can be represented as (1) TV + ERV (2) ERV + RV (3) RV + IRV (4) ERV + TV + IRV 6000 to 8000 ml of air is the (1) Vital capacity of lungs (2) Volume of normal expiration per minute (3) Sum of IRV + ERV (4) Inspiratory capacity of lungs

6.

7.

8.

9.

10.

The volume of air that remains in the lungs after normal expiration is (1) Residual volume (2) Vital capacity (3) Expiratory capacity (4) Functional residual capacity Mark incorrect statement in the following (1) Diffusion membrane is made up of 3-major layers (2) Solubility of CO2 is higher than O2 by 25 times (3) Breathing volumes are estimated by spirometer (4) High cone. of hydrogen ions favours oxyhaemoglobin formation Every 100 ml of oxygenated blood delivers following amount of O2 to the tissues under normal physiological contition (1) 5 ml (2) 25 ml (3) 50 ml (4) More the 50 ml The pneumotaxic centre that can moderate the function of respiratory rhythm centre is located in (1) Dorsal side of medulla (2) Ventral side of medulla (3) Aortic arch and carotid artery (4) Pons What will be the pO2 and pCO2 in the atmospheric air as compared to that of alveolar air (1) pO2 lesser and pCO2 higher (2) pO2 higher and pCO2 lesser (3) Both pO2 and pCO2 lesser (4) Both pO2 and pCO2 higher

BREATHING AND EXCHANGE OF GASES

687

EXERCISE - 2 | Window to Competitive Exams 1.

2.

3.

4.

5.

6.

7.

8.

9.

During transport of CO2, blood does not become acidic due to [CBSE ‘95] (1) neutralization of H2CO3 by Na2CO3 (2) absorption by leucocytes (3) blood buffers (4) nonaccumulation Oxy-Haemoglobin dissociation curve is [BHU ‘95] (1) Sigmoid (2) Hyperbolic (3) Straight line (4) Parabolic The affinity of CO with Hb is more than oxygen by [CBSE ‘95] (1) 2 times (2) 20 times (3) 200 times (4) 2000 times Partial pressure of oxygen in inspired and expired air is ……. and ……. mm of Hg [CET Chd. ‘95] (1) 100, 46 (2) 158, 40 (3) 158, 90 (4) 100, 95 The organ of sound production in birds is [Haryana ‘95] (1) Larynx, and is present at the base of Trachea (2) Syrinx, and is present at the base of Trachea (3) Larynx, and is present at the top of Trachea (4) Syrinx, and is present at the top of Trachea Presence of large number of alveoli around alveolar ducts opening into bronchioles in mammalian lungs is [CBSE ‘95] (1) Inefficient system of ventilation with little of residual air (2) Inefficient system of ventilation with high percentage of residual air (3) An efficient system of ventilation with no residual air (4) An efficient system of ventilation with little residual air What percentage of oxygen is carried by haemoglobin ? [CPMT ‘96] (1) 90 (2) 98 (3) 23 (4) 73 Earthworm respires through [CPMT ‘96] (1) Moist skin (2) Ctenidia (3) Citellum (4) Typhlosole Which one of the following is called inspiratory muscle in mammals? [PCS ‘96] (1) Radial muscle of diaphragm (2) External intercostal muscle (3) Internal intercostal muscle (4) Pleural muscle

10.

11. 12. 13.

14.

15.

16.

17.

18.

19.

When 1200 mL air is left in the lungs, it is called [CBSE ‘96] (1) Vital capacity (2) Tidal volume (3) Residual volume (4) Inspiratory reserve volume Total lungs capacity is approximately [Haryana ‘97] (1) 1200 ml (2) 2400 ml (3) 4000 ml (4) 5800 ml Efficiency of respiration is [HPMT ‘97] (1) 40% (2) 60% (3) 90% (4) 30% The impulse for voluntary (forced) breathing starts in [Haryana ‘97] (1) medulla (2) Vagus (3) Cerebral hemisphere (4) Spinal cord One common feature between trachea of rabbit and trachea of cockroach is that both [AFMC ‘94; Haryana ‘97] (1) Are paired and branched (2) Have ciliated epithelium (3) Originate in pharynx in head region (4) Have non-collapsible walls. Carbon dioxide amount in atmospheric air normally is [CBSE ‘97] (1) 3% (2) 0.4% (3) 0.3% (4) 0.04% Which of the following statement correctly defines Bohr effect ? [AIIMS ‘95; Haryana ‘97] (1) Rise in p50 with a decrease in CO2 conc. (2) Rise in p50 with decrease in pH (3) Rise in p50 with increase in O2 (4) Fall in p50 with decrease in pH In lungs, the air is separated from the venous blood through. [CBSE ‘97] (1) Squamous epithelium + endothelium of blood vessel (2) Squamous epithelium + tunica externa, media & interna of blood vessels (3) Squamous epithelium + basement membrane + endothelium of blood vessels (4) None of these The stage when the lungs are collapsed, specially the alveoli due to deficiency of surfactant, it is called [Haryana ‘98] (1) Atelactasis (2) Poliomyelitis (3) Asthma (4) Epistaxis Dyspnea is the [Haryana ‘98] (1) Normal breathing (2) Difficult breathing (3) Rapid breathing (4) Stage without breathing.

688 20.

21.

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24.

25.

26.

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31.

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33.

BIOLOGY Trachea is double in [Haryana ‘98] (1) Echidna (2) Penguins (3) Whale (4) Dolphins No respiratory pigment is found in [CPMT ‘98] (1) Cockroach (2) Earthworm (3) Rabbit (4) Frog Tidal volume in human beings is [BHU ‘98] (1) 1500 mL (2) 800 mL (3) 1200 mL (4) 500 mL Respiratory coefficient is [HPMT ‘95; CET Chd. ‘99] (1) The amount of CO2 produced to O2 absorbed (2) The amount of O2 obtained to the amount of O2 consumed (3) Always more than one (4) Always less than one Oxygen carrier or the respiratory pigment in the blood of frog and other vertebrates is [CPMT ‘81, 83, 87, 92; AFMC ‘81; AIIMS ‘81; CBSE ‘99] (1) Haemocyanin (2) Cytochrome (3) Haemoglobin (4) None of these The movement of true vocal cords in man is controlled by cartilages [JIPMER ‘99] (1) arytenoids (2) cricoid (3) thyroid (4) both (1) and (2) The structure which prevents the entry of food into the windpipe is [Kerala 2000] (1) Gullet (2) Glottis (3) Tonsil (4) Epiglottis In which of the following animals respiration occurs without a respiratory organ ? [CPMT 2000] (1) Fish (2) Cockroach (3) Tadpole (4) Earthworm Amount of oxygen carried by 1 gm. of haemoglobin, is [Haryana 2000] (1) 1.34 ml (2) 13.4 ml (3) 134 ml (4) 20 ml Alveoli increase the surface area by [Punjab 2000] (1) 10 m2 (2) 100 m2 (3) 150 m2 (4) 200 m2 Which one of the following appendages of prawn bears a podobranch? [PCS 2000] (1) Maxilla (2) Second maxillipede (3) Maxillula (4) Second chelate leg Voice in mammal is produced [MP 2000] (1) by syrinx (2) during inhalation (3) by bronchus (4) during exalation Book lungs are respiratory organs of [DPMT ‘01] (1) Molluscs (2) Mammals (3) Arachnids (4) Earthworm Carbonic anhydrase is found in high concentration in [CBSE ‘91, CPMT ‘94, PCS 2000, ‘01] (1) leucocytes (2) blood plasma (3) erythrocytes (4) lymphocytes

34.

What can determine the percentage of oxygen carried by Hb ? [CET Chd. ‘01] (1) pH of blood (2) Percentage of CO2 (3) Partial pressure of oxygen (4) All above

35.

During CO2 transport, HCO3− diffuses from erythrocyges to plasma and in turn upsets the ionic equilibrium momentary. In order to keep the ionic balance, and equal number of Cl– ions pass into the erythrocytes from plasma. This process is known as [Kerala ‘01] (1) Bicarbonate shift (2) Carbonation (3) Hamburger phenomenon (4) Carbo-chlorosis In which part the gaseous exchange takes place in rabbit? [RPMT ‘01] (1) alveoli and blood (2) trachea and bronchi (3) trachea and alveolar duct (4) alveolar duct and alveoli Bicarbonate ions can be generated in [MP ‘01] (1) Lymphocytes (2) Neutrophil (3) basophil (4) RBCs About 70% of CO2 is transported as [BVP ‘02] (1) Carbonic acid (2) Carboxyhaemoglobin (3) Bicarbonates (4) Carbamino compounds R.Q. is less than 1 for [RPMT ‘02] (1) starch (2) organic acid (3) protein (4) carbohydrate The total lung capacity is represented by [PCS ‘02] (1) tidal volume + vital capacity (2) tidal volume + residual volume (3) vital capacity + residual volume (4) inspiratory and expiratory reserve volumes When the Respiratory Quotient (R.Q.) is greater than 1, it indicates [AFMC ‘02] (1) only aerobic respiration is taking place (2) only anaerobic respiration is taking place (3) both aerobic and anaerobic respirtation are taking place (4) none of these Oxyhaemoglobin dissociates into oxygen and deoxyhaemoglobin at [JIPMER ‘02] (1) low O2 pressure in tissue (2) high O2 pressure in tissue (3) equal O2 pressure inside and outside tissue (4) all times irrespective of O2 pressure The correct match for kind of respiration is [Haryana ‘02]

36.

37. 38.

39. 40.

41.

42.

43.

A. B. C. D.

Animal Earthworm Human Prawn Insects

1. 2. 3. 4.

Respiration Pulmonary Branchial Tracheal Cutaneous

BREATHING AND EXCHANGE OF GASES

44.

45.

46.

47.

48.

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50.

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(1) 1-A, 2-B, 3-C, 4-D (2) 4-A, 2-B, 1-C, 3-D (3) 4-A, 1-B, 2-C, 3-D (4) 3-A, 2-B, 4-C, 1-D Exchange of gases in lungs is by [AFMC ‘02] (1) Simple diffusion (2) Active transport (3) Passive transport (4) Osmosis Enzyme involved in CO2 transport in blood is [Orissa ‘02] (1) carboxylase (2) carboxykinase (3) carbonic anhydrase (4) none of these The covering of lungs is called [AFMC ‘02] (1) Pleura (2) Pericardia (3) Peritoneum (4) Mediastenum The volume of air breathed in and out during normal breathing is called [Kerala ‘02] (1) Vital capacity (2) Inspiratory reserve volume (3) Explratory reserve volume (4) Tidal volume Hamburger phenomenon is also known as [CPMT ‘90; AIIMS ‘94; JIPMER ‘02] (1) Calcium shift (2) Bohr effect (3) Chloride shift (4) Na+ -K+ pump Vital capacity of lungs in terms of IRV(Inspiratory Reserve Volume), ERV (Expiratory Reserve Volume), TV (Tidal Volume) and RV (Residual Volume) can be represented as [KCET ‘02] (1) IRV + ERV + TV + RV (2) IRV + ERV + TV (3) IRV + ERV (4) IRV + ERV + TV - RV Dissociation curve shifts to the right when (1) pH increases [MP ‘02] (2) CO2 concentration increases (3) O2 concentration decreases (4) 2, 3 D P G decreases Intercostal muscles are found attached with (1) Diaphragm (2) ribs [AFMC ‘02] (3) plcura (4) Lungs Which of the following is correct regarding respiration? [Punjab ‘03] (1) no organism can live without respiration (2) it takes place at every time day and night (3) it involves production of carbon dioxide and water (4) all of these Which structure is not related with respirtation in frog? [Manipal ‘03] (1) lungs (2) skin (3) buccal cavity (4) diaphragm Trachea is absent in [Jharkhand ‘03] (1) insects (2) arachnids (3) crustaceans (4) mammals

689 55.

56.

57. 58.

59.

60.

61.

62.

63.

64.

Which one of the following has the smallest diameter? [Kerala ‘03] (1) Trachea (2) Secondary bronchiole (3) Respiratory bronchiole (4) Left primary bronchus With reference to human respiration, which is correct? [Orissa ‘03] (1) Pulmonary ventilation is equal to alveolar ventilation (2) Alveolar ventilation is more than pulmonary ventilation (3) Alveolar ventilation is less than pulmonary ventilation (4) Pulmonary ventilation is less than alveolar ventilation R.Q. is [DPMT ‘03] (1) CO2/O2 (2) O2/CO2 (3) N2/CO2 (4) CO2/N2 During oxygen transport the oxyhaemoglobin at the tissue level liberates oxygen to the cells because in tissue [EAMCET ‘03] (1) O2 concentration is high and CO2 is low (2) O2 concentration is low and CO2 is high (3) O2 tension is high and CO2 tension is low (4) O2 tension is low and CO2 tension is high The correct statement in respect of protein haemoglobin is that it [CBSE ‘04] (1) maintains blood sugar level (2) acts as an oxygen carrier in the blood (3) functions as a catalyst for biological reactions (4) forms antibodies and offers resistance to diseases When CO2 concentration in blood increases, breathing becomes [CBSE ‘04] (1) slow and deep (2) faster and deeper (3) shallower and slow (4) there is no effect on breathing Blood analysis of a patient reveals an unusually high quantity of carboxyhaemoglobin content. Which of the following conclusions is most likely to be correct? The patient has been inhaling polluted air containing usually high content of [CBSE ‘04] (1) Chloroform (2) Carbon dioxide (3) Carbon monoxide (4) carbon disulphide When carbohydrate is subjected to aerobic respiration what will be the R.Q. ? [CPMT ‘98; BCECE ‘05] (1) 1.0 (2) 0 (3) 1.7 (4) 1.4 Approximate amount of O2 in expired air is [Haryana ‘97, ‘05] (1) 16% (2) 4.6% (3) 19% (4) < 1% Rate of breathing in mammals largely depends upon [CPMT ‘93; Kerala ‘05] (1) Oxygen concentration in blood (2) CO2 concentration in blood (3) Volume of O2 in trachea (4) Extent of depression of dia diaphragm

690 65.

66.

67.

68.

69.

70.

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72.

BIOLOGY Maximum amount of oxygen is exchanged from the blood in the ............... [KCET ‘05] (1) capillaries-surrounding tissue cells (2) arteries of the body (3) left auricle of the heart (4) capillaries surrounding the alveoli. Lungs ventilation movements are due to (1) coastal muscle and diaphragm [Orissa ‘05] (2) coastal muscle (3) diaphragm (4) wall of the lungs. Formation of non-functional methaemoglobin causes bluebaby syndrome. This is due to [AIIMS ‘05] (1) excess of arsenic concentration in drinking water (2) excess of nitrates in drinking water (3) deficiency of iron in food (4) increased methane content in the atmosphere. Capacity of human lung for air in healthy man is (1) 3000 ml (2) 1500 ml [Orissa ‘05] (3) 1000 ml (4) 500 ml Which of the following conditions is responsible for increase in ventilation rate of lungs ? [CPMT ‘05] (1) increase of CO2 content in inhaled air (2) increase of CO2 content in exhaled air (3) decrease in O2 content of inhaled air (4) decrease in O2 content of exhaled air Black lung disease is common in [Orissa ‘05] (1) coal miners (2) refinery workers (3) petrochemical industry (4) farmers CO2 transport in the body mainly occurs in the form of (1) carbaminohaemoglobin [BCECE ‘05] (2) dissolved in plasma (3) C + O2 (4) bicarbonates HCO3–2 Match the disorders given in column I with symptoms under column II. Choose the answer which gives the correct combination of alphabets with numbers. [Kerala ‘05] A. B. C. D.

(1) (2) (3) (4)

Column I Asthma Bronchitis Rhinitis Amphysema

1. 2. 3. 4. 5.

Column II Inflammation of nasal tract Spasm of bronchial muscles Fully blown out alveoli Inflammation of bronchi Cough with blood strained sputum

A = 4, B = 2, C = 5, D = 1 A = 5, B = 3, C = 2, D = 1 A = 3, B = 1, C = 5, D = 4 A = 2, B = 4, C = 1, D = 3

73.

74.

75.

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80.

Ascent to high mountains may cause altitude sickness in men. The prime cause of this is (1) excess of CO2 in blood [CPMT ‘05] (2) decreased efficiency of haemoglobin (3) decreased partial pressure of oxygen (4) decreased proportion of oxygen in air In lungs, there is definite exchange of ions between RBC and plasma. Removal of CO2 from blood involves [CPMT ‘05] (1) influx of Cl– ions into RBC (2) influx of HCO3– ions into RBC (3) efflux of Cl– ions from RBC (4) efflux of HCO3– ions from RBC If R. Q. is 0.6 in a respiratory metabolism, it would mean that [Kerala ‘05] (1) carbohydrates are used as respiratory substrate. (2) Organic acids are used as respiratory substrate (3) The oxidation of the respiratory substrate consumed more oxygen than the amount of CO2 released (4) the oxidation of the respiratory substrate consumed less oxygen than the amount of CO2 released. After taking a long deep breath we do not respire for some seconds due to [BHU ‘05] (1) more CO2 in blood (2) more O2 in blood (3) less CO2 in blood (4) less O2 in blood Which one of the following statements is incorrect ? [CBSE ‘06] (1) The presence of non-respiratory air sacs, increases the efficiency of respiration in birds (2) In insects, circulating body fluids serve to distribute oxygen to tissues (3) The principle of countercurrent flow facilitates efficient respiration in gills of fishes (4) The residual are in lungs slightly decreases the efficiency of respriration in mammals The majority of carbon dioxide produced by our body cells is transported to the lungs (1) as bicarbonates [CBSE ‘06; BHU’06] (2) as carbonates (3) attached to hemoglobin (4) dissolved in the blood The ‘blue body’ syndrome results from (1) methemoglobin [CBSE ‘06] (2) excess of dissolved oxygen (3) excess of TDS (total dissolved solids) (4) excess of chloride Identify the correct statement with reference to transport of respiratory gases by blood ? [KCET ‘06] (1) Haemoglobin is necessary for transport of carbon dioxide and carbonic anhydrase for transport of oxygen (2) haemoglobin is necessary for transport of oxygen and carbonic anhydrase for transport of carbon dioxide (3) only oxygen is transported by blood (4) only carbon dioxide is transported by blood.

BREATHING AND EXCHANGE OF GASES 81.

82.

83.

84.

85.

86.

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About 1000 ml of air is always known to remain inside the human lungs. It is described as (1) inspiratory reserve volume [KCET ‘06] (2) expiratory reserve volume (3) residual volume (4) tidal volume The amount of air remaining in the air passages and alveoli at the end of quiet respiration is (1) tidal volume [JK ‘06] (2) inspirating reserve volume (3) inspirating capacity (4) functional residual capacity In man total number of alveoli in both lungs is (1) 300000000 (2) 30000 [Orissa’06] (3) 500000000 (4) 700000000 At rest body produces CO2 at the rate of [Orissa’06] (1) 100 cc/min (2) 300 cc/min (3) 400 cc/min (4) 600 cc/min Membrane separating air in pulmonary alveoli from blood capillaries is [Orissa’06] (1) alveolar epithelium (2) cardiac epithelium (3) endothelium of blood capillaries (4) both (1) and (3) Food and air pathway are divided at [Orissa’06] (1) larynx (2) pharynx (3) oesophagus (4) stomach Which of the following statements are true/false? (a) The blood transports CO 2 comparatively easily because of its higher solubility. (b) Approximately 8 -.9% of CO2 is transported being dissolved in the plasma of blood (c) The carbon dioxide produced by the tissues, diffuses passively into the blood stream and passes into red blood corpuscles and react with water to form H2CO3 (d) The oxyhaemoglobin (HbO2) of the erythrocytes is basic. (e) The chloride ions diffuse from plasma into the erythrocytes to maintain ionic balance. [Kerala’06] (1) a. c and e are ture b and d are false (2) a, c and e are false, b and d are true (3) a, b, and d are true, c and e are false (4) a, b and d are false c and e are true In the following statements [Kerala’06 A. Carbonic anhydrase is present in the erythrocytes B. In erythrocytes the carbon dioxide combine with water and is transported. (1) statement A is correct and is responsible for statement B

691

89.

90.

91.

92.

93.

94.

95.

96.

(2) statement A is not correct but statement B is correct (3) both statement A and B are wrong (4) statement A is correct but not involved in statement B Carboxyhaemoglobin complex results due to this pollutant? [JK ‘06] (1) CO2 (2) CO (3) H2CO3 (4) SO2 Besides RBC, blood plasma also carries O2 in solution. The % is [Orissa’06] (1) 3 – 9% (2) 1 – 2% (3) 3 – 6% (4) 2 – 3% What is vital capacity of our lungs? [CBSE ‘08] (1) Total lung capcity minus residual volume (2) Inspiratory reserve volume plus tidal volume (3) Total lung capacity minus expiratory reserve volume (4) Inspiratory reserve volume plus expiratory reserve volume Listed below are four respiratory capacities (a-d) and four jumbled respiratory volume of a normal human adult: [CBSE ‘10] Respiratory capacities Respiratory volumes (a) Residual volume 2500 mL (b) Vital capacity 3500 mL (c) Inspiratory reserve volume 1200 mL (d) Inspiratory capacity 4500 mL What is true about RBCs in humans? [CBSE ‘10] (1) They do not carry CO2 at all (2) They carry about 20-25 per cent of CO2 (3) They transport 99.5 per cent of O2 (4) They transport about 80 per cent oxygen only and the rest 20 per cent of it is transported in dissolved state in blood plasma The urge to inhale in humans results from [DPMT’10] (1) Rising PCO2 (2) Rising PO2 (3) Falling PCO2 (4) Falling PO2 A large proportion of oxygen is left unused the human blood even after its uptake by the body tissues. This O2 [CBSE’11] (1) Helps in releasing more O2 to the epithelium tissues (2) Acts as a reserve during muscular exercise (3) Raises the pCO2 of blood to 75 mm of Hg (4) Is enough to keep oxyhaemoglobin saturation at 96% Two friends are eating together on a dining table. One of them suddenly starts coughing while swallowing some food. This coughing would have been due to improper movement of [CBSE’11] (1) Tongue (2) Epiglottis (3) Diaphragm (4) Neck

692 97.

BIOLOGY The figure given below shows a small part of human lung where exchange of gases takes place. In which one of the options given below, the one part A, B, C or D is correctly identified along with its function? [CBSE’11]

103. The figure shows a diagrammatic view of human respiratory system with labels A, B, C and D. Select the option which gives the correct identification and main function and or characteristic. [AIPMT (NEET)’13]

D C

A

B

Options (1) B : Red blood cell - transport of CO2 mainly (2) C : Arterial capillary - passes oxygen to tissues (3) A : alveolar cavity - main site of exchange of respiratory gases (4) D : Capillary wall - exchange of O2 and CO2 takes place here 98. Bulk of carbon dioxide (CO2) released from body tissues into the blood is present as [CBSE Final’11] (1) 70% carbamino-haemoglobin and 30% as bicarbonate (2) Carbamino-haemoglobin in RBCs (3) Bicarbonate in blood plasma and RBCs (4) Free CO2 in blood plasma 99. Which one of the following is a possibility for most of us in regard to breathing, by making a conscious effort ? [CBSE Final’11] (1) One can consciously breathe in and breathe out by moving the diaphragm alone, without moving the ribs at all (2) The lungs can be made fully empty by forcefully breathing out all air from them (3) One can breathe out air totally without oxygen (4) One can breathe out air through Eustachian tubes by closing both the nose and the mouth 100. At present the concentration of CO2 in the atmosphere is about [DPMT’11] (1) 100 ppm (2) 240 ppm (3) 380 ppm (4) 520 ppm 101. Hiccups can be best described as: [DPMT’11] (1) Forceful sudden expiration (2) Jerky incomplete inspiration (3) Vibration of the soft palate during breathing (4) Sign of indigestion 102. Which one of the following is the correct statement for respiration in humans? [CBSE’12] (1) Workers in grinding and stone-breaking industries may suffer from lung fibrosis (2) About 90% of carbon dioxide (CO2) is carried by haemoglobin as carbaminohaemoglobin (3) Cigarette smoking may lead to inflammation of bronchi (4) Neural signals from pneumotoxic centre in pons region of brain can increase the duration of inspiration

104.

105.

106.

107.

108.

(1) A- trachea- a long tube supported by complete cartilaginous rings for conducting inspired air (2) B- pleural membrane- surroundtibs on both sides to provide cushion against rubbing (3) C- alveoli- thin walled vascular bag like structures for exchange of gases (4) D- lower end of lungs – diaphragm pulls it down during inspiration The inspiratory reserve volume + tidal volume + expiratory reserve volume is the same as: [AMU’13] (1) Inspiratory capacity + expiratory reserve volume (2) Total lung capacity – functional residual capacity (3) Inspiratory capacity + functional residual capacity (4) Inspiratory capacity + residual volume Between breaths the intra-pleural pressure is approximately _______ mmHg less than atmospheric pressure [AMU’13] (1) 1 (2) 4 (3) 8 (4) 10 Approximately seventy percent of carbon dioxide absorbed by the blood will be transported to the lungs: [AIPMT’14] (1) As bicarbonate ions (2) In the form of dissolved gas molecules (3) By binding to RBCs (4) Ascarbamino- haemoglobin When you hold your breath, which of the following gas changes in blood would first lead to the urge to breathe? [AIPMT’15] (1) Falling O2 concentration (2) Rising CO2 concentration (3) Falling CO2 concentration (4) Rising CO2 and falling O2 concentration Name the pulmonary disease in which alveolar surface area involved in gas exchange is drastically reduced due to damage in the alveolar walls: [RE-TEST AIPMT’15] (1) Emphysema (2) Pneumonia (3) Asthma (4) Pleurisy

BREATHING AND EXCHANGE OF GASES [UPCPMT’15] 109. Carbonic Anhydrase is found in: (1) Lymphocytes (2) Blood plasma (3) Erythrocytes (4) Leucocytes 110. Partial pressures of oxygen and carbon dioxide in healthy human lung alveoli are, respectively, nearest to: [AMU’15] (1) 140 and 40 mm of Hg (2) 90 and 20 mm of Hg (3) 40 and 45 mm of Hg (4) 159 and 0.3 mm of Hg 111. Which of the following set of conditions promotes the dissociation of oxygen from haemoglobin? [AMU’15] (1) Low pO2, high pCO2, high H+ (2) High pO2, high pCO2, low H+ (3) High pO2, low pCO2, low H+ (4) Low pO2, low pCO2, low H+ 112. The pneumotaxic centre and respiratory rhythm centres are respectively present in: [AMU’15] (1) Pons and Medulla oblongata (2) Corpus callosum and Pons (3) Medulla oblongata and Hypothalamus (4) Diencephalon and Pons

693 113. With respect to its body mass which of the following will have the highest metabolic rate? [AMU’15] (1) Rat (2) Rabbit (3) Horse (4) Elephant 114. Which of the following is the most appropriate in normal circumstances? [AMU’15] (1) During inspiration the intrapulmonary pressure is less than the atmospheric pressure (2) During expiration, the intrapulmonary pressure is less than the atmospheric pressure (3) During inspiration, the intrapulmonary pressure is more than the atmospheric pressure (4) During expiration the intrapulmonary pressure is equal to the atmospheric pressure 115. The volume of air that will remain in the lungs after a normal expiration is called: [KERALA’15] (1) Vital capacity (2) Functional residual capacity (3) Residual volume (4) Total lung capacity 116. The entry of food into the larynx is prevented by: [KERALA’15] (1) Mitral valve (2) Diaphragm (3) Epiglottis (4) Hyoid

694

BIOLOGY

EXERCISE - 3 | Test Yourself 1.

2.

3.

4. 5.

6.

7.

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9.

10.

Dead space air is (1) The amount of air left in lungs after deepest expiration. (2) About 150 ml (3) Both of these (4) None of these. When fully saturated, one molecule of oxyhaemoglobin carries following number of oxygen molecules. (1) Two (2) Three (3) Four (4) None of these Which of the following breathing process in human is passive (1) Expiration (2) Aspiration (3) Inspiration (4) Forced breathing The amount of oxygen in tidal vol. is approximately (1) 1 litre (2) 3 litre (3) 100 ml (4) 500 ml Carbon-di-oxide combines with haemoglobin (1) 200- 250 times more readily than oxygen (2) Twice less readily than oxygen (3) 20- 25 times more readily than oxygen (4) 100 times less readily than oxygen The chloride content of RBC will be higher than that of plasma in (1) Systemic arteries and pulmonary veins (2) Systemic veins and pulmonary arteries (3) Systemic and pulmonary arteries (4) Systemic and pulmonary veins Bysinosis is an occupational lung disease which may occur in (1) Cement factory workers (2) Cotton mill workers (3) Sugar mill workers (4) Coal miners The amount of air inhaled forcibly after normal breathing is called(1) Residual volume (2) Supplementary air (3) Expiratory reserve volume (4) None of these Adam’s apple is formed by(1) Cricoid cartilage which is ring shaped (2) Thyroid cartilage which is unpaired (3) Arytenoid cartilage which is paired (4) None of these Emphysema developes mainly because of (1) Allergy or hypersensitisation (2) Spasm of the smooth muscles of bronchioles (3) Cigarette smoking (4) Inflammation of the alveoli

11. 12.

13.

14.

15.

16.

17. 18.

19.

20. 21.

The disorder related to inhalation of cotton fibres is called(1) Anthracosis (2) Byssinosis (3) Atelectasis (4) Hay fever Which of the following can respire anaerobically in human body? (1) Liver (2) RBCs (3) Skeletal muscles (4) Both (2) and (3) Forceful expiration is mediated via (1) Dorsal group of Neurons (2) Ventral group of Neurons (3) Pneumotaxic centre (4) Hering Breurer Reflex If the volume of CO2 liberated during respiration is more than the volume of O2 used, the respiratory substrate will be : (1) Fat (2) Organic acid (3) Protein (4) Carbohydrate Formation of carbamino- compounds is(1) Regulated by enzyme arginase (2) Regulated by enzyme carbonic anhydrase (3) A non-enzymatic process (4) Inhibited by cyanide In the process of formation of oxyhaemoglobin from haemoglobin(1) Oxidation occurs (2) Ferrous form is converted into ferric form (3) Both (1) and (2) correct (4) Neither oxidation occurs nor there is a change of ferrous form into ferric form The value of R.Q. is the maximum for(1) Carbohydrates (2) Proteins (3) Fats (4) Organic acid Which of the following activity is more difficult during bronchial asthma? (1) Inspiration (2) Forced inspiration (3) Expiration (4) Transportation of oxygen Residual air is present in (1) Lungs (2) Trachea (3) Bronchi and bronchioles (4) Both (2) and (3) Normal vital capacity of human adult is about (1) 4600 ml (2) 3200 ml (3) 1200 ml (4) 500 ml Difficulty in breathing is called (1) Apnoea (2) Dyspnoea (3) Hypercapnoea (4) Eupnoea

BREATHING AND EXCHANGE OF GASES 22. 23.

24. 25.

26. 27.

28.

29.

30.

31.

32.

Whale respires through (1) Gills (2) Lungs (3) Skin and gills (4) Skin and lungs Vital capacity is the maximum amount of air which can be breathed out after (1) Inhaling tidal volume only (2) Exhaling tidal volume (3) Inhaling tidal volume and complementary air (4) Exhaling supplementary air The breathing rate per minute in human is approximately (1) 14 (2) 72 (3) 120 (4) 80 Which of the following cartilage in laryngo-tracheal chamber of frog is absent? (1) Cricoid (2) Arytenoid (3) Thyroid (4) Arytenoid and cricoid Cutaneous respiration in frog occurs during (1) Swimming (2) Hibernation (3) Resting stage (4) All of these The contribution of diaphragm in breathing in a 25 years old female is about (1) 25 - 35 % (2) 75 – 80 % (3) 35 – 45% (4) 50% Deoxyhaemoglobin binds with more H+ than oxyhaemoglobin does. It is described by (1) Bohr’s effect (2) Hering - Breuer reflex (3) Haldane’s effect (4) Hamburger’s effect Oxygen dissociation curve for Myoglobin has following shape (1) Sigmoid (2) Straight line (3) Rectangular Hyperbola (4) None of these Earthworm does not have special respiratory structures because (1) Haemocoel is present (2) A Cylindrical shape gives high surface area to volume ratio (3) Arteries and veins are not differentiated (4) Respiratory pigment is dissolved in plasma The unpaired cartilages in human larynx are (1) Arytenoid and crecoid (2) Thyriod, cricoid and epiglottis (3) Corniculate and epiglottis (4) Arytenoid, cuneiform and corniculate Functional residual capacity in human is the amount of air (1) That can be filled in lungs by forceful inspiration (2) That can be breathed out after forceful expiration (3) That remains in the lungs after normal expiration (4) That remains in the lungs after forceful expiration

695 33.

34.

35. 36.

37.

38.

39.

40.

Basic respiratory rhythm is generated by (1) Dorsal respiratory group of neurons (2) Ventral respiratory group of neurons (3) Pneumotaxic centre of medulla oblongata (4) Pneumotaxic centre of pons varolli Mark the correct statement(1) Human lungs are negative pressure type (2) Avian lungs are non-elastic (3) Right lung in human is 3-lobed (4) All are correct Glottis is the opening between pharynx and the (1) Internal nostrils (2) Larynx (3) Buccal cavity (4) Oesophagus Following is the correct order of diffusion rate of oxygen, carbon – di- oxide and nitrogen from lungs to blood through the respiratory membrane (1) CO2 > O2 > N2 (2) CO2 > N2 > O2 (3) O2 > CO2 > N2 (4) O2 > N2 > CO2 Carbon-di-oxide is the excretory product in (1) Aerobic respiration (2) Anaerobic respiration (3) Both types of respiration (4) Terrestrial animals and plants only Mark the correct statement (1) Volume of residual air is higher than tidal volume (2) Volume of complementary air is higher than tidal volume (3) Volume of supplementary air is lower than residual capacity (4) All of these If the oxyhaemoglobin dissociation curves of maternal and foetal haemoglobin are compared, the foetal curve will be on (1) Right hand side and sigmoid (2) Left hand side and sigmoid (3) Right hand side and parabola (4) Left hand side and parabola Given below are four matches of animals with their respiratory organs A. Silver fish – trachea B. Scorpion – book lungs C. Sea squirt – pharyngeal gills D. Dolphin – skin The correct matchings are (1) C and D (2) A and D (3) A, B and C (4) B and D

696

BIOLOGY

ANSWER KEY (2) (2)

8. 9. 10.

(4) (2) (3)

EXERCISE 2 : WINDOW TO COMPETITIVE EXAMS

11.

(2)

12. 13. 15. 16.

(4) (2) (3) (4)

17.

(4)

18. 19. 20. 21. 22. 24. 25. 26.

(3) (1) (1) (2) (2) (1) (3) (4)

27. 28.

(2) (3)

29. 32. 33.

(3) (3) (1)

The amount of air left in lungs after the deepest expiration is- Residual air. One molecule of Haemoglobin contains four molecule of Haem, so four iron atoms, for carrying for molecules of Oxygen.

34.

(4)

35. 36.

(2) (1)

Oxygen is 21% in the air (Tidal volume = 500ml). Diffusion of carbon-di-oxide is about 20 times faster than oxygen. 7. (2)

37. 39.

(3) (2)

40.

(3)

EXERCISE 1 : NCERT BASED QUESTIONS 1. 6.

(3) (4)

1. 6. 11. 16. 21. 26. 31. 36. 41. 46. 51. 56. 61. 66. 71. 76. 81. 86. 91. 96. 101. 106. 111. 116.

(3) (4) (4) (2) (1) (4) (4) (1) (2) (1) (2) (2) (3) (1) (4) (3) (3) (2) (1) (2) (2) (1) (1) (3)

2. 7.

2. 7. 12. 17. 22. 27. 32. 37. 42. 47. 52. 57. 62. 67. 72. 77. 82. 87. 92. 97. 102. 107. 112.

(3) (4)

(1) (2) (1) (3) (4) (4) (3) (4) (1) (4) (4) (1) (1) (2) (4) (2) (4) (1) (4) (3) (1) (2) (1)

3. 8.

3. 8. 13. 18. 23. 28. 33. 38. 43. 48. 53. 58. 63. 68. 73. 78. 83. 88. 93. 98. 103. 108. 113.

(1) (1)

(3) (1) (3) (1) (1) (1) (3) (3) (3) (3) (4) (4) (1) (1) (3) (1) (1) (1) (2) (3) (3) (1) (1)

4. 9.

4. 9. 14. 19. 24. 29. 34. 39. 44. 49. 54. 59. 64. 69. 74. 79. 84. 89. 94. 99. 104. 109. 114.

(2) (4)

(2) (2) (4) (2) (3) (2) (4) (3) (1) (2) (3) (2) (2) (1) (4) (1) (2) (2) (1) (1) (1) (3) (1)

5. 10.

5. 10. 15. 20. 25. 30. 35. 40. 45. 50. 55. 60. 65. 70. 75. 80. 85. 90. 95. 100. 105. 110. 115.

(2) (3) (4) (2) (1) (2) (3) (3) (3) (2) (3) (2) (1) (1) (3) (2) (4) (4) (2) (3) (2) (1) (2)

EXERCISE 3 : TEST YOURSELF 1.

(2)

2.

(3)

3. 4. 5.

(1) (3) (3)

6.

(2)

This air is called Inspiratory reserve volume (IRV). The smooth muscles of bronchioles show spasmic contraction during expiration in asthma. Atelectasis is the defective expansion of lungs at birth. Both form lactic acid in anaerobic respiration. 14. (2) The enzyme CA regulates bi-carbonate formation. The formation of oxyhaemoglobin is, therefore, called the process of oxygenation. Organic acids use less oxygen so have more value of RQ (ratio of carbon-di-oxide to oxygen). In asthma there is spasmic contraction of bronchioles. Trachea and bronchioles have dead space air. All mammals have lungs as respiratory structure. 23. (3) Heart beat in human is 72 per minute. During aestivation and hibernation the cutaneous is the only mode of respiration in frog. This is the reason why deoxyhaemoglobin can carry more carbon-di-oxide. 30. (2) 31. (2) This includes RV and ERV (2500ml). Pons varolli contains ‘On and off’ switch of breathing. In human lungs the pressure decreases before the air is drawn into them. Oxygen diffuses two times faster than nitrogen, while carbon-di-oxide diffuses 20 times faster than oxygen. 38. (4) Foetal haemoglobin has higher affinity than maternal haemoglobin for oxygen. In Dolphin (mammal) the respiration can not be cutaneous.

18

Chapter

Body Fluids and Circulation Body Fluids and Circulation While going through the chapter pay special attention to the following – Terms and definitions1. Systemic heart 4. Myogenic heart 7. Pace maker 10. Portal vein

2. 5. 8.

Mitral valve Pulse pressure Thoracic duct

Differences – 1. Open and closed BVS 3. Single and double circulation 5. Arteriosclerosis and atherosclerosis 7. Lymph and serum Peculiarities – 1. Heart of crocodile Disorders 1. Angina 3. ECG abnormalities

3. 6. 9.

2. 4. 6.

Papillary muscles Sphygmomanometer Christmas factor

Tachycardia and Bradycardia 1st and 2nd heart sounds Arteries and veins

At a Glance 

Blood vascular system

   

Human heart

2. 4.

BVS of a fish Fibrillation Myocardial infarction

    

Valves

Conducting system Heart beat

Control of heart beat

E.C.G. (E.K.G.)

Heart disorders Blood pressure

 2.

Closed blood vascular system

Type of hearts

      

Open blood vascular system

Pulse & pulse pressure

Arteries, veins and capillaries Arterial system in human Venous system in human Lymphatic system Blood clotting

Angiology − Study of blood vascular system. William Harvey (a British scientist) is the ‘Father of Angiology’. He studied blood vascular system (BVS) in a live snake. His monograph on blood circulation was named, ‘Anatomical exercise on the motion of the heart and blood’. Fabricius (Guru of William Harvey) discovered valves in (longer) veins. Marcello Malpighii (Founder of histology) discovered blood capillaries. Connecting Concepts BVS first time developed in Phylum Annelida. Protozoans to Aschelminthes do not have heart  Cardiology is the study of heart and or BVS. related functions, while Haematology is the study of blood. Blood Vascular System is of 2−types. 1. Open blood vascular system. 2. Closed blood vascular system 1. OPEN BLOOD VASCULAR SYSTEM • In this type of BVS the blood is filled in sinuses or lacunae which together for a large blood filled cavity called Haemocoel. • Capillaries−network is lacking. • Such system is present in all the members of Phylum Arthropoda and a few members of Phylum Mollusca (eg. Pila, Unio). In echinoderms the BVS is very much reduced, and is called Haemal system.

698

BIOLOGY 2.

CLOSED BLOOD VASCULAR SYSTEM • In this type of BVS the blood does not come out of the vessels and, hence, haemocoel is lacking. • The Capillaries−network is present. • Such system is present in all the members of subphylum Vertebrata, phylum Annelida* and few members of Phylum Mollusca (eg. Octopus, Squid). • * The Leech (an annelid), however, has haemocoelomic system, consisting of haemocoelomic channels (not true blood vessels) which are derived from coelomic cavity. The closed blood vascular system is of 2−types. Single Circulation System− In such system, for one complete circulation through the body, the blood passes only once through the heart . Such animals, therefore, have only deoxygenated blood in the heart. Such heart is known as Venous heart, eg Fishes LUNGS

ated blo ygen od Ox

Gills Respiration organs

Deoxygenated blood

Body Organs Deoxygenated blood Deoxygenated blood

Deoxygenated blood

PULMONARY Oxygenated CIRCULATION blood

A HEARTA V V

SYSTEMIC Oxygenated CIRCULATION blood

Heart

(A)

BODY ORGANS (B)

Fig. 18.1 : (A) Single circulation system in fishes, (B) Double circulation system in mammals

Double Circulation System− In such system, for one complete circulation through the body, the blood passes twice through the heart: (i) To the lungs and back− It is called Pulmonary circulation or Lesser circulation (due to Lesser distance of the lungs from the heart. (ii) To the body organs and back− It is called Systemic circulation or Greater circulation (covering greater distance from heart to the body−organs. eg. Amphibians, Reptiles, Birds and Mammals. (Because of single ventricle, the amphibians and reptiles have incomplete double circulation)

Heart From origin point of view the whole BVS, including heart, is Mesodermal. The heart is one of the first organ to be completed in embryo.

Survey of Hearts in Important Groups  

In earthworm (Phylum Annelida) eight hearts (4−pairs) are present.Two pairs are true hearts and two pairs false. ((For For details please refer Chapter 77)) In Cockroach ( Phylum Arthropoda) the heart is single and dorsal in position. It is 13−chambered chambered (3+10). In Prawn ((Palaemon) the heart contains only oxygenated blood because the deoxygenated blood from the body directly goes to the gills. The oxygenated blood from there finally goes to the heart

BODY FLUIDS AND CIRCULATION

699



In Urochordates (ex. Herdmania) the heart is tubular or sac-like. This heart has 2-‘Pacemakers’ and the flow of blood is reversed periodically. In Amphioxus ((Branchiostoma), there is no true heart and blood is collected into Sinus Venosus.



In fishes the heart is 2−chambered, 1−Atrium(A) and 1−Ventricle(V). As mentioned above, the heart of fishes is Venous heart.



In Amphibians the heart is 3−chambered (2A+1V). Because of single Ventricle the blood in frog is mixed in this chamber. ((For detailed structure of Frog’s heart, please refer Chapter 77).



In Reptiles the heart in general, is incompletely 4−chambered. However, in Crocodile and Alligator the heart is completely 4−chambered (2A+2V).



In Birds and Mammals the heart is always 4−chambered (2A+2V).

HUMAN HEART 

It is 10−12 cm in size, and is present in the Mediastinum (space) of the thoracic-cavity .



It weighs ~250 g in males and 225 g in females.



The apex of the heart is ~9 cm to the left of the mid line



The heart is covered by a transparent serous membrane, the pericardium (the parietal mesoderm/peritoneum). The pericardial fluid between heart and the pericardium keeps the heart moist and protects it from friction and mechanical injury.



The wall of the heart has 3- coatings, Epicardium (Outer), Myocardium (Middle) and Endocardium (Inner). The myocardium contains cardiac muscles.



The atria and ventricles are divided by Coronary Sulcus.



Two Atria are separated by Interatrial septum. In foetus this septum contains Foramen ovale (opening) and the blood from right atrium (oxygenated blood from Placenta) passes to the left atrium. At the time of birth when placenta is detached this passage is closed to form Fossa ovalis. If Foramen ovale is left open after first few weeks of life, it is referred as a ‘hole in the heart’.



The left side of the heart (Lt. A and Lt. V) contains oxygenated (pure) blood and the right side (Rt. A and Rt. V) has deoxygenated (impure) blood.



Lt. atrium receives oxygenated blood through 2−pairs of pulmonary veins (2 per lung).



Rt. atrium receives deoxygenated blood through 1−Precaval or Anterior Vena Cava and 1−Post caval or posterior Vena cava (Rabbit has 2−Precavals).



Lt. and Rt. ventiricles are separated by interventicular septum.

Rt. pulmonary artery

Lt. pulmonary artery Lt. pulmonary veins

Superior vena cava Tricuspid valve Inferior vena cava Eustachian valve Chordae Tendinae

Systemic aorta

Lt atrium

Rt. atrium

Bicuspid valve Lt. ventricle

Rt. ventricle

Papillary muscles

Fig. 18.2 : Internal structure of Human heart (simplified)

Check Point 1. Fill in the blanks with suitable word/ statement : (i) ........................ is called father of Angiology. (ii) ....................... valve is present between Lt. atrium and Lt. ventricle. (iii) In fish heart there is ..................... circulation system. (iv) All arthropods have .................... blood vascular system (v) ....................... is called pace maker of human heart. (vi) ‘Lesser circulation’ is between ...................... and ....................... (vii) Bicuspid and tricuspid valves are .......................during joint diastole. (viii) In mammals the systemic aorta lies in ..............side of the heart.

700

BIOLOGY Connecting Concepts

 Lt. part of the heart (Lt. atrium and Lt. ventricle), having oxygenated blood, is called Systemic heart.

Connecting Concepts  In frog’s heart there is a triangular chamber on the dorsal side, called Sinus Venosus. The deoxygenated blood through 2−precavals and 1−postcaval is first filled into this chamber and from here it goes to Rt. atrium. Sinus Venosus is lacking in the heart of birds and mammals. (For detailed structure of Frog’s heart, please refer Chapter 6)

Lt.ventricle and Rt. ventricle receive oxygenated and deoxygenated blood from respective atria.  From Lt.ventricle oxygenated blood is supplied to the body organs through systemic aorta. From Rt. ventricle deoxygenated blood is supplied to lungs through pulmonary aorta  The wall of the Lt.ventricle, which supplies oxygentated blood to all body organs, is thickest of all the chambers.  Systemic aorta in Amphibians and reptiles is paired. In birds and mammals it is unpaired (single).In birds it is right and in mammals it is left. Valves i. Eustachian valve− A flap of this valve is present at the opening of the post caval and prevents the back flow of the blood. The major portion of this valve is vestigial. ii. Thebasian valve− It is present at the opening of coronary sinus which receives deoxygenated blood from cardiac muscles. iii. Atrio−ventricular valves− In Lt. side there is Bicuspid (2−flaps) valve between Lt. atrium and Lt. ventricle. This is also known as Mitral valve. In between Rt. atrium and Rt. ventricle there is a 3−flapped Tricuspid valve. The flaps of both Bicuspid and Tricuspid valve are attached to Papillary muscles through Chordae Tendinae. These prevent reverting of the valves during contraction of ventricles. Bicuspid is the only valve in mamalian heart which always remains in contact of the pure (oxygentated) blood. All other type of valves come in contact of deoxygenated blood. (The base of the anterior papillary muscles is connected to the interventricular septum by a special band of cardiac muscles, called Moderator band.) iv. Semilunar valves− These are present at the base of aorta and each has three pockets which are filled with blood to prevent its back flow to the ventricles. 

Conducting System or Nodal Tissue Like all other vertebrates, in human also, the heart is Myogenic, i.e. the heart beat is

Connecting Concepts

 Amongst non-chordates or generated by muscles and not nerves invertebrates, Mollusca is the only  The heart beat is generated through Sino atrial node (SAN) which is also known as Pace phylum in which the heart is Myogenic. maker. It is a bundle of specialized cardiac muscles. (These muscles like other muscles, In Arthropods the heart is Neurogenic are not contractile but are specialized for conducting impulses like nerve fibres). ( Heart beat is generated by nerve  In human SA node is embedded in the wall of Rt. atrium. In frog’s heart it is present in fibres).

 

the wall of Sinus Venosus. Atrio−ventricular node (AVN) is present in inter−atrial septum, close to Tricuspid valve. (The AV node is absent in frog’s heart). From AV node arises a bundle of specialized muscle fibres, called Bundle of His or Atrio−ventricular bundle. This runs in the anterior part of inter-ventricular septum and then bifurcates. The branches ramify in the walls of ventricles as Purkinje fibres.

precaval LA S.A. Node Inter nodal pathway A.V.Node

Bundle of His LV

Post caval RV

Inter ventricular septum Purkinje (Purkyne) fibres

Fig. 18.3 : Conducting system in human heart

BODY FLUIDS AND CIRCULATION

701

Heart Beat   

The rate of heart beat in a adult human is ~72 per minute. The single heart beat is called Cardiac cycle and takes 0.8 sec (60 sec / 72 beats ). Each Cardiac cycle consists of 3−parts. 1. Atrial systole (0.1 sec) 2. Ventricular systole (0.3 sec) 3. Diastole (joint) (0.4 sec) (The heart beat in newly born child is ~100 per min while in foetus it is ~140 per min.)

Chamber Systole Diastole Atrium 0.1 sec 0.7 sec Ventricle 0.3 sec 0.5 sec  Stroke volume ~70 ml  It is the amount of blood pumped out from each ventricle per beat.  Cardiac output ~5 litre  It is the output of the heart per unit time (70 ml x 72 beats per min.)  Cardiac index ~ 3.2 litre / m2 It is Cardiac output per square meter of the body surface per min. i.e. (5 lit. / 1.6 m2). Factors affecting heart beat−  Heart beat increases during excitement, eating, exercise, fever and pregnancy.  Heart beat decreases during sleep and shock.  Heart beat is more in males than in females.  Heart beat increases with the increase of altitude (Heart beat ∝ altitude).  The heart beat increases with the decrease of animal size (Heart beat ∝ 1/size). If elephant, human and mouse are compared the heart beat will be highest in mouse and lowest in elephant.  Heart beat ∝ 1/BP (except in exercises, in which both blood pressure (BP) and the rate of heart beat, increase). Control of Heart beat− (a) Chemical Control (i) Adrenaline− This hormone stimulates heart beat either directly or through sympathetic nervous system. (ii) Thyroxine− This increases metabolic rate and hence heart beat. (b) Nervous Control Medulla oblongata has two regulatory centre − (i) Accelerator centre− It functions through sympathetic nervous system (SNS) and increases heart beat by the secretion of epinephrine or adrenaline. (ii) Depressor centre− It functions through parasympathetic nervous system (PSNS) by the secretion of acetylcholine. It decreases heart beat.

Heart Sound In each cardiac cycle, though the heart produces 4−sounds but only 1st and 2nd sound can be heard by Stethoscope. These sounds are described below: 1. 1st Sound −  It sounds like LUBB.  It is of longer duration.  It is of lower frequency (low pitch).  It is louder (volume ↑).  When ?− At the beginning of ventricular systole and coincides with the ‘R’ wave of ECG. Why ?− Mainly because of closing of Bicuspid and Tricuspid valves.

Check Point 1. Differentiate between : (i) Open and closed blood vascular system. (ii) Pulmonary and systemic circulation (iii) Myogenic and Neurogenic heart. (iv) Tachycardia and Bradycardia. (v) Cardiac output and cardiac index. (vi) SA node and AV node (vii) Foramen ovale and fossa ovalis

Connecting Concepts  PSNS fibres to the heart pass through Vagus (10th cranial nerve). If Vagus is cut the secretion of acetylcholine is also cut and the heart beat increases due to continuous supply of adrenaline. If, on the other hand, Vagus is stimulated the secretion of acetylcholine through PSNS fibres increases and heart beat decreases.  The increase of Heart beat is called Tachycardia, while decrease of heart beat is called Bradycardia.

702

BIOLOGY 2.

2nd Sound − • It sounds like DUP. • It is of shorter duration. • It is sharper (high frequency). • It is softer (low volume) When ?− At the end of ventricular systole and coincides with the ‘T’ wave of ECG. Why ?− Because of closing of the semilunar valves of systemic aorta and pulmonary aorta.

E.C.G. (E.K.G.) The instrument which records electrical activity of the heart muscles is called Electrocardiograph. The sketch obtained on the graph paper is called electrocardiogram (or electrokardiogram). • The standard symbols used for ECG are PQRST, where P* represents atrial depolarisation; Connecting Concepts QRS* complex represents ventricular depolarisation and T* represents ventricular  Resting potential in cardiac muscle repolarisation. (P, R & T are deflection waves). fibres is − 90 mV and not − 70 mV as Atrial systole in an average sized neuron. Cardiac (0.1 s) R muscles do not show tetanus also. Ventricular systole (0.3 s) Joint Diastole P

(0.4 s)

T

P

ST Interval (0.32 s)

PR Interval (0.18 s) S

QRS Interval (0.08 s)

0

0.2

0.4

0.6

0.8sec

Fig. 18.4 : An Electrocardiogram (ECG)

Intervals in Normal ECG Interval PR (or PQ)

Average duration 0.18 sec (180 mili sec)

QRS

0.08 sec (80 ms)

Event Atrial depolarisation and conduction through AV node Ve n t r i c u l a r d e p o l a r i s a t i o n a n d a t r i a l repolarisation Ventricular repolarisation

ST 0.32 sec (320 ms) Abnormality of ECG 1. In rheumatic heart disease (valves damaged) and arteriosclerotic heart desease (due to formation of plaque or calcification) there is inflammation of atria and AV node, which results in the lengthening of PR interval. 2. When heart muscles receive insufficient oxygen (lesser blood supply− heart ischaemia), the ST segment is depressed and T wave is flatenned. 3. In acute myocardial infarction the ST segment is elevated and Q & R waves are enlarged. 4. In case of hyperkalemia (K+↑↑) T wave is very tall and slender. * ‘P’ - wave occurs slightly before the onset of Atrial contraction (systole). * QRS - waves (complex) begin slightly before the onset of ventricular systole. * ‘T’-wave occurs slightly before the end of ventricular systole.

BODY FLUIDS AND CIRCULATION R P

703

T Q S PQ or PR

(1) Lengthening of PR interval (Rheumatic Fever)

T S

ST (2) ST segment depressed (Heart ischaemia)

T

S

P

P Q

R

R

R

T Q

(3) ST segment elevated (Myocardial infarction)

P Q S

(4) T wave taller (Hyperkalemia)

Fig. 18.5 : Abnormalities in ECG

Heart Disorders 1.

2.

3. 4.

5.

Heart Ischaemia − The blood supply to the heart muscles (myocardium) is reduced (a) Angina pectoris− Blood supply to the heart muscles is reduced because of narrowing of the coronary artery. In such a case there is no problem in routine work but pain develops during exercise or exertion. (b) Myocardial infarction− In this case the blood supply is totally blocked and the part of heart tissue becomes dead. The death results mainly from fibrillation. Heart Block− In atrio−ventricular block there is delay between atrial and ventricular systole. PR > 0.2 sec. In such a case AV node is either not stimulated or stimulation is delayed. In bundle branch-block QRS > 0.1 sec. (If atrial impulse suddenly fails to be transmitted to the ventricles, it is called Ventricular escape or Adam’s syndrome). Rheumatic Heart Disease− It develops due to recurrence of rheumatic fever. The heart valves are damaged due to formation of antibodies. It is an autoimmune disorder. Persistent ductus arteriosus − In foetus pulmonary aorta and systematic aorta are connected by ductus arteriosus. At birth it degenerates. Rarely it persists and the blood supply to systemic aorta is reduced which causes congestion in lungs. Fibrillation - A rapid, irregular, abnormal, asynchronous and ineffective contraction of cardiac muscles is called fibrillation. Atrial fibrillation may occur due to Rheumatic heart disease and myocardial infarction. The ventricular fibrillation may be produced by electrocution. If ventricular fibrillation lasts for more than a few minutes, it can be fatal. It can be stopped by electric shocks or by electronic defibrillators. The latter can be implanted in the persons of high risks. Atherosclerosis− It is the disorder of arteries (blood vessels) in which cholesterol (plaque) is deposited. Arteriosclerosis− It is the hardening of arteries due to calcification in old age. The elasticity of the vessles is reduced. This may also result from atherosclerosis. Thrombosis− It is the clotting of blood inside the blood vessels.

BLOOD PRESSURE The pressure exerted by the blood on the walls of blood vessels is called blood pressure (BP). The blood pressure in all the arteries is relatively very high, but drops with distance away from the heart.  BP decreases from arteries to veins (arteries > capillaries > veins)  BP is measured by Sphygmomanometer on Brachial artery of upper arm (generally of left side).  In adults the normal BP is 120/80.  120 mm of Hg is systolic pressure during contraction of ventricles, and 80 mm of Hg is diastolic pressure during relaxation of ventricles.  In children the BP is low as compared to adults.  In old age the average BP is 150/90, as the arteries become less elastic.  The chemicals which are vasodialator decrease the blood pressure while vasoconstrictors increase the blood pressure. The Histamine is a vasodialator and adrenaline is a vasoconstrictor.

Check Point 1. Name the followings : (i) Instrument used for measuring Blood pressure. (ii) Standard symbols used for ECG. (iii) The blood vessel at which pulse is felt. (iv) The artery that carries deoxygenated blood. (v) Disorder of arteries due to cholesterol deposition. (vi) Difference between systolic and diastolic pressure (vii) When heart muscles are suddenly damaged by inadequate blood supply (viii) Acute chest pain when enough oxygen is not reaching heart muscles.

704

BIOLOGY

PULSE Pulse is a wave of distension, i.e., a rhythmic expansion and relaxation (not contraction) of arteries. • Pulse is felt at radial artery, of wrist. • With the help of pulse the heart beat can be measured.

Pulse Pressure • •

It is the difference between systolic and diastolic pressure. In normal adult the value of pulse pressure is 40 mm of Hg (120 mm−80 mm).

ARTERIES, VEINS AND CAPILLARIES

Connecting Concepts  In arterioles, the smallest branches of arterial system, the tunica media does not have elastic fibres and consists of smooth muscles only. The arterioles, therefore, can regulate the amount of blood flowing to the tissues.

Each artery has three coats, viz (i) Tunica externa (adventitia), (ii) T. media and (iii) T. interna (intima). (1) Tunica externa mainly consist of white fibrous connective tissue (collagen fibres). (2) Tunica media contains elastic fibres and smooth muscles. The arteries near the heart have lot of elastic fibres, and those farther from the heart have proportionately more smooth muscles (muscular tissue). (3) Tunica interna has endothelial layer (simple squamous epithelium) or intima layer with elastic fibres. (In atherosclerosis the cholesterol or other fatty materials are deposited in sub−intimal layer). Arteries 1. 2. 3. 4. 5. 6. 7. 8. 9.

Veins

More elastic Tunica media very thick Lumen narrow Valves absent

1. Less elastic 2. Tunica media thin 3. Lumen broader 4. Valves (semilunar) present in (longer) veins Lie deeper in the body 5. Generally superficial All, except* pulmonary artery, carry 6. All, except pulmonary vein, carry oxygenated blood deoxygenated blood. Blood flow is jerky or discontinuous 7. Blood flow is continuous These vessels carry blood away from 8. These carry blood towards heart. the heart. They contain ~13% of the blood at 9. They contain ~ 65% of the blood at a a time time Tunica externa (collagen fibres)

Endothelium

Tunica media (smooth muscles & elastic fibres)

(a) Artery

Tunica interna or Endothelium

(b) Vein

Fig. 18.6 : Histology of Blood Vessels * Like pulmonary artery, the Umbilical artery of foetus also carries deoxygenated blood.

(c) Capillary

BODY FLUIDS AND CIRCULATION

705

Capillaries • •

Tunica externa and T. media are absent. There are no collagen fibres, no elastin fibres and no smooth muscles. Only endothelial lining with basement membrane is present. (The capillary network supplying outer layer of larger blood vessels is called Vasovasorum)

ARTERIAL SYSTEM IN HUMAN 2− major aorta − 1. Pulmonary aorta, 2. Systemic aorta Pulmonary aorta arises from Rt. ventricle and supplies deoxygenated blood to the lungs.

Connecting Concepts

 In mammals there is Lt. systemic Systemic aorta arises from Lt. ventricle and gives out following important arteries. aorta. In birds it is Rt. systemic aorta. In both it is unpaired. In amphibians (a) Coronary artery− It supplies blood to the heart muscles. (Frog) and reptiles the systemic aorta (b) Innominate artery− (Rt. Brachio- cephalic artery) − It bifurcates into Rt. subclavian is paired.

and Rt. common carotid artery.

(c)

Lt. common carotid artery− It divides into external and internal carotid arteries.

(d)

Lt. subclavian − it arises independently from the aorta. Rt. carotid artery External carotid Internal carotid Vertebral artery Clavicle (bone) Brachial aretery Lt. common carotid artery Mammillary artery Lt. Subclavian artery Doral aorta

Rt. subclavian artery BrachioCephalic artery or Innominale artery Systemic aorta Coronary artery

LV

Bronchial artery

Thoracic aorta Ocsophageal artery Intereostal arteries (9-pairs) Dlaphragm Phrenic artery Abdominal aorta Coclic artery Anterior Mesenteric artery Renal artery Posterior mesenteric artery Lt. common Iliac artery Internal Iliac artery External Iliac artery

Fig. 18.7 : Arterial system in Human

Blood supply− 1.

Internal carotid supplies oxygenated blood to the brain while external carotid supplies blood to the other parts of the head.

2.

Brachial arises from subclavian artery and supplies blood to the arm.

3.

Mammary artery also arises from subclavian artery and supplies blood to the pericardium.

Systemic aorta now takes a turn and comes to the dorsal side of the heart. This dorsal aorta is differentiated into Thoracic aorta (in thoracic region) and Abdominal aorta (in abdominal region).

706

BIOLOGY Important arteries arising from thoracic aorta− 1. Oesophageal artery− supplies blood to oesophagus. 2. Intercostal artery− supplies blood to intercostal muscles in between the ribs. 3. Bronchial artery− supplies oxygenated blood to the lungs. Important Arteries arising from abdominal aorta− (a) Paired arteries− e.g. Phrenic artery, Renal artery and Gonadial artery. Phrenic artery− supplies blood to diaphragm. Renal artery− supplies blood to kidney. Gonadial artery− supplies blood to gonads. (b) Unpaired arteries− e.g. Coeliac artery, Anterior (superior) mesenteric and Posterior (inferior) mesenteric arteries. Coeliac artery− supplies blood to stomach, pancreas, spleen and liver etc. Anterior mesentric artery− supplies blood to small intestine. Posterior mesentric artery− supplies blood mainly to the large intestine. In the posterior most region the abdominal aorta bifurcates into Rt and Lt. common iliac arteries. Each iliac artery then divides into external and internal iliacs. External iliac enters the leg and outer branch of it is called Femoral artery.

VENOUS SYSTEM IN HUMAN Portal Vein − It is a vein that arises as capillaries from one organ and terminates as capillaries in the other organ. Portal vein is different from other veins as it does not carry blood Connecting Concepts directly to the heart. The system formed by portal veins is called Portal system.  The name of the portal system is given after the name of the organ Portal system is of 2-types into which the portal vein terminates, Minor portal system− e.g. Hepatic portal system : the vein terminates into liver and Renal portal  system : the vein terminates into  kidney.



The portal vein of this system is shorter. Such system is present between hypothalamus (the floor of diencephalon)and anterior pituitary. This system is meant for transferring the releasing factors (Hormones) from Hypothalamus to the Anterior pituitary.

This portal system is also known as Hypophyseal portal system as it terminates into Hypophysis -cerebri (pituitary). Major portal system−  The portal veins in this system are longer.  There are two such portal systems in vertebrates. (a) Hepatic portal system− 



It is present in all vertebrates.



It starts from alimentary canal and terminates into liver.

 (b)

It brings digestive end products to the liver before releasing them (in modified form) into the blood. Renal portal system−



It is present in lower vertebrates (fishes and amphibians) only. In reptiles it is reduced.



It starts from fins in fishes and from hind limbs in amphibians (frog).



It terminates into kidney. ((For For details of this system, in ‘Frog’, please refer chapter 66))

BODY FLUIDS AND CIRCULATION

707

Internal Jugular Vein

External Jugular Vein

Subclavian vein Brachiocephalic vein

Precaval

Rt A Diaphragm

Postcaval Hepatic veins

Check Point 1. What are the target organs of the following blood vessels? (i) Phrenic artery (ii) Coeliac artery (iii) Internal carotid artery (iv) Bronchial artery (v) External iliac artery

Renal vein Gonadial vein

Rt. Common iliac vein

Inferior vena cava or post caval Internal iliac vein Ext. Iliac vein Check Point

Femoral vein

Saphenous vein Fig. 18.8 : Venous system in human

The V Venous system in human includes 1−Precaval and 1−Postcaval. 

Precaval or superior venacava is formed by the combination of 2−Brachiocephalic veins.



Each brachiocephalic vein is formed by the union of internal jugular vein and subclavian vein. External jugular runs down to join subclavian vein.



The venous blood from brain is collected by internal jugular vein.



The subclavian vein (below clavicle bone) collects deoxygented blood from arms.



Thoracic blood is collected by Azygos, Hemizygos, Oesophageal, Intercostal and Bronchial veins.



Postcaval or inferior venacava is formed by the joining of Rt. and Lt. common iliac vein.



Hepatic vein, renal vein and gonadial veins join postcaval.

1. Answer the followings : (i) From which organ does the Hepatic portal system collect the blood? (ii) Which blood vessel collects the blood from brain? (iii) From which portal system does the anterior pituitary receive releasing hormones. (iv) Which is the longest vein in human body? (v) At what stage of cardiac cycle does the Ist heart sound appear?



Connecting Concepts From hind limbs the venous blood is collected through Femoral and Saphenous veins. The  The Saphenous vein is the longest Femoral vein ascends in to the abdominal region and becomes external iliac vein. vein in human body and is also used



The renal portal system is absent in mammals.

LYMPHATIC SYSTEM 

It is the characteristic feature of all vertebrates.



Lymphatic vessels are comparable to blood capillaries and veins. There is no counter part of arteries in lymphatic system. (All systems, except CNS, have lymphatic circulation .)



As in longer veins, the valves are present in the lymphatic vessels also.



In lower vertebrates (fishes and amphibians) the lymphatic hearts are also present ( In frog there are 4−such hearts, 2-Thoracic and 2–abdominal).



In mammals lymphatic hearts are absent but lymph nodes are present.

in coronary artery bypass grafting (CABG).

708

BIOLOGY 

The lymph capillaries in human form lymph vessels, which join to form lymphatic ducts.



The lymphatic duct of the left side is called Thoracic duct. In Rt. side there is Rt. lymphatic duct.



Both Lt. thoracic duct and Rt. lymphatic duct pour the lymph into subclavian vein of their side.

Lymph − 

It is mostly described as Blood minus RBCs. It can also be represented as plasma plus WBCs. In lymph the number of WBCs is lesser but the number of lymphocytes is greater than blood.



In comparison to blood plasma, the proteins in lymph are fewer.



Like plasma the lymph also contains fibrinogen and hence can clot.



The lymph outside the lymph vessels is known as tissue fluid or interstitial fluid or extra cellular fluid (ECF).

BLOOD CLOTTING (HAEMOSTASIS) The clot or coagulam is a dark -reddish brown ‘scum’ formed mainly by a network of threads in which dead or damaged blood elements are trapped. 

It is the property of plasma.



Normal blood clotting time is 3−10 min.



The clot inside the blood vessels is called thrombus. A moving thrombus is called embolus.



In haemophilia (a sex linked disease) the blood clotting is delayed.



According to Macferlane hypothesis there are 13−factors responsible for blood clotting (or coagulation). The 4−factors are primary and 9−factors are accessory for this process.

Primary factors (I) Fibrinogen (II) Prothrombin (III) Thromboplastin (Thrombokinase) (IV) Calcium ions Connecting Concepts



 Heparin (a polysaccharide) is a  natural anticoagulant in the blood and  prevents the conversion of prothrombin into thrombin in circulating blood. It is secreted from liver (mainly) and mast cells.

The first 3−factors are proteinaceous in nature. The Prothrombin (II factor) is synthesized in liver in the presence of vitamin K. The Thromboplastin is released from injured platelets or injured tissue. This converts prothrombin into thrombin in the presence of calcium ions. The thrombin converts fibrinogen into fibrin, the latter forms the clot. The blood cells are entangled in the network of fibrin. A straw -coloured fluid, separated from clot, is called Serum. As the Serum does not have fibrinogen, it can not clot.

Thromboplastin or Thrombokinase (III) (an enzyme-complex from injured platelets /tissues)

Prothrombin (II)

++

Thrombin

Ca (IV) Fibrinogen (I)

Fibrin

Fig. 18.9 : Role of primary factors (I to IV) in blood clotting

BODY FLUIDS AND CIRCULATION Accessory factors (V)

Labile factor (Proaccelerin) − It helps in complete conversion of prothrombin into thrombin.

(VI)

No separate entity, hence No specific name (existence existence doubtful doubtful).

(VII) Stable factor (Proconvertin) − It accelerates the formation of active thromboplastin. (VIII) Anti−haemophilic globulin (AHG)− The absence of this factor delays blood clotting causing Haemophilia−A. This type of haemophilia is most common (80%). (IX)

Plasma thromboplastin co−factor (PTC)− The deficiency of this factor causes Haemophilia−B. Approximately 20% of haemophilic patients have this type of haemophilia. The IX factor is also known as Christmas factor, and Haemophilia B is known as ‘Christmas disease’.

(X)

Stuart Prower factor− It helps in the conversion of prothrombin into thrombin.

(XI)

Plasma thromboplastin antecedent (PTA)− It activates the inactive christmas factor. The deficiency of this causes a rare type of bleeder-disease, called Haemophilia -C.

(XII) Hageman’s factor or Glass factor − It converts inactive PTA into active form. It also dilates blood vessels for increasing their permeability. (XIII) Fibrin stabilizing factor− It causes polymerization of soluble fibrin into insoluble fibrin and also inhibits depolymerization. Factors slowing blood clotting− (a) Inside body− Heparin is a natural anticoagulant present in the blood. It prevents conversion of prothrombin into thrombin and does not allow blood coagulation inside blood vessels. (b) Outside body− sodium citrate, sodium oxalate, double oxalate and EDTA (ethylene diamine tetra acetic acid) and the other chelating agents bind with free calcium and prevent the conversion of prothrombin into thrombin. Dicumarol and Warfarin inhibit the action of vitamin K (anti- prothrombin function) and thus prevent blood clotting. Factors hastening blood clotting− (a) Inside body− Vitamin K, which is essential for the synthesis of prothrombin in the liver, if injected into the body, during haemorrhage, stimulates blood clotting. (b) Outside body− The blood oozing out from injured part can be coagulated by applying pressure or providing rough surface (for injuring more platelets) or by increasing the temperature (to activate blood clotting− enzymes).

709 Check Point 1. Answer the followings : (i) According to Macferlane hypothesis how many factors are responsible for blood clotting? (ii) Which Haemophilia is also known as christmas disease? (iii) Name the natural anticoagulant of the blood? (iv) Which vitamin is responsible for the synthesis of Prothrombin? (v) What are the primary factors for blood clotting? (vi) The absence of which factor causes classical haemophilia? (vii) What is the name of left lymphatic duct (viii) Which blood clotting factor is inorganic in nature?

Check Point 1. Differentiate between : (i) Thrombus and Embolus (ii) Lymph and ECF (iii) The role of Dicumarol and Sodium oxalate in blood clotting (iv) Thrombin and Thrombokinase (v) Serum and Plasma.

710

BIOLOGY

EXERCISE - 1 | NCERT BASED QUESTIONS 1.

Which of the following set of animals has an incomplete double circulation system

(1) Oxygenated blood from liver to intestine (2) Deoxygenated blood from liver to intestine

(2) Shark and whale

(3) Oxygenated blood from intestine to liver

(3) Lizard and pigeon

(4) Deoxygenated blood from intestine to liver 6.

(1) Heart failure

(2) Cardiac arrest

(1) The ability to generate action potential due to any external stimuli

(3) Atherosclerosis

(4) Thrombosis

7.

(3) P u r k i n j e f i b r e s t h r o u g h o u t t h e v e n t i c u l a r musculature (4) Atrioventricular node, also called pacemaker During joint diastole (1) Both atria relax but ventricles contract (2) Both ventricles relax but atria contract (3) Both semi lunar valves are open (4) Tricuspid and bicuspid valves are open 4.

Coronary artery disease (CAD) is ofter referred to as

Nodal tissue/musculature in human heart has

(2) Two patches, one in atrium and other in ventricle

3.

Hepatic portal system carries

(1) Frog and crocodile

(4) Toad and lizard 2.

5.

Mark incorrect statement regarding normal ECG (1) Patient is connected to 3 electrical leads (one to each wrist and to the left ankle)

8.

Fastest distribution of some injectible material/medicine and with no risk of any kind can be achieved by injecting it into the (1) Muscles

(2) Arteries

(3) Veins

(4) Lymph vessels

Given below are four statements (a-d) regarding human blood circulatory system (a) Arteries are thick-walled and have narrow lumen as compared to veins (b) Angina is acute chest pain when the blood circulation to the brain is reduced (c) Persons with blood group AB can donate blood to any person with any blood group under ABO system

(2) ‘T’ wave represents atrial repolarization

(d) Calcium ions play a very important role in blood clotting

(3) Q marks the beginning of ventricular systole

Which two of the above statements are correct?

(4) R represents ventricular depolarization

(1) (a) & (d)

(2)

(a) & (b)

(3) (b) & (c)

(4)

(c) & (d)

BODY FLUIDS AND CIRCULATION

711

EXERCISE - 2 | Window to Competitive Exams 1.

2.

3.

4.

5.

6.

7.

8.

9.

10.

11.

12.

Which of the following carries oxygenated blood? [AFMC ‘95] (1) Renal vein (2) Hepatic portal vein (3) Hepatic vein (4) Pulmonary vein Heart beat in arthropods and annelids is [Haryana ‘95] (1) myogenic (2) neurogenic (3) both the above (4) none of these The heart sound ‘murmur’ is heard during [Haryana ‘95] (1) Closing of bicuspid and tricuspid valves (2) Closer of semiluner valves (3) Leaking of blood through valves (4) All of these Lymph [CBSE ‘95] (1) transports oxygen to brain (2) transport CO2 to lungs (3) returns interstitial fluid to blood (4) returns RBCs and WBCs to lymph nodes Carotid artery supplies blood to [EAMCET ‘95] (1) Brain (2) Skin (3) Lung (4) Limbs Chordae tendinae are found in [AIIMS ‘96] (1) Joints of legs (2) atria of heart (3) ventricles of brain (4) ventricles of heart Lymph is modified blood that contains [Haryana ‘96] (1) RBC and WBC (2) RBC, WBC and protein (3) WBC and all protein (4) All contents of blood except RBC and certain protein Mitral valve in mammals guards the opening between [HPMT ‘96] (1) left auricle and left-ventricle (2) pulmonary vein and left auricle (3) stomach and intestine (4) liver and spleen Foramen of panizzae is found in the heart of (1) Frog (2) Pigeon [PCS ‘96] (3) Crocodile (4) Rabbit Open type blood vascular system is found in (1) Earthworm (2) Lizard [PCS ‘96] (3) Cockroach (4) Toad Right systemic arch is absent in [AMU ‘97] (1) reptiles (2) birds (3) mammals (4) none of the above Physiology of blood circulation was first described by [BHU ‘82, CPMT ‘97] (1) William Harvey (2) Karl Landsteiner (3) Andreas Vesalius (4) Carl Correns

13.

14.

15.

16.

17.

18.

19.

20.

21.

22.

23.

24.

The contraction of the heart of frog commences from (1) right auricle [AFMC ‘98] (2) left auricle (3) interauricular septum (4) sinus venosus Renal portal system is absent in [BHU ‘98] (1) birds (2) reptiles (3) amphibians (4) reptiles & amphibians The precaval vein is formed of [BVP ‘98] (1) external jugular and innominate (2) innominate and subclavian (3) external jugular, innominate and subclavian (4) external jugular and subclavian Cardiac cycle in man takes about [Haryana ‘98] (1) 0.5 seconds (2) 1.0 second (3) 1.2 seconds (4) 0.8 seconds The pigment haemocyanin is found in [CPMT ‘98] (1) Mollusca (2) Echinodermata (3) Insecta (4) Annelida In mammals the blood from the right ventricle goes to [Punjab ‘98] (1) systemic aorta (2) precavals (3) truncus arteriosus (4) pulmonary aorta Contraction of the ventricle in the heart begins by the command from [CBSE ‘99] (1) Purkinje fibres (2) AV node (3) Chordae tendina e (4) SA node A muscular wall is absent in [CPMT ‘99] (1) Venule (2) Vein (3) Capillary (4) Arteriole An open circulatory system occurs in [KCET ‘99] (1) Reptiles (2) Man (3) Animals (4) Insects The heartbeat of a person increases at the time of an interview due to secretion of [AIIMS ‘99] (1) Renin (2) Adrenaline (3) ADH (4) ACTH Which layer of the wall of blood vessels is made up of circular smooth muscles? [BHU 2000] (1) Outer (2) Middle (3) Inner (4) both (1) and (2) Which artery is absent in frog? [MP 2000] (1) Renal artery (2) Carotid artery (3) Phrenic artery (4) Right systemic arch

712 25.

26.

27.

28.

29.

30.

31.

32.

33.

34.

35.

36.

BIOLOGY Heart is simple tubular and ventral in [Kerala 2000] (1) urochordata (2) cyclostomata (3) cephalochordata (4) vertebrate Blood pressure is measured by [AIIMS 2000] (1) sphygmomanometer (2) stethoscope (3) electrocardiogram (4) phonocardiogram Heart of prawn carries [Punjab 2000] (1) oxygenated blood (2) deoxygenated blood (3) mixed blood (4) no blood Cardiac output is [Kerala 2000] (1) the product of heart rate and stroke volume (2) the product of auricular and ventricular volume (3) the blood pumped in one minute (4) both (1) and (3) Which of the following is the largest lymphatic vessels of the human body? [PCS 2000] (1) Lacteal duct (2) Thoracic duct (3) Cisterna chyli (4) Right lymphatic duct Artery differs from vein in having [Punjab 2000] (1) narrow wall (2) thick walls (3) valves (4) none above Which one of the following will be the cardiac output (in litres per minute) of a heart that has a stroke volume of 0.07 litres and is beating at a rate of 90 per minute? [PCS 2000] (1) 63.30 (2) 63.00 (3) 00. 63 (4) 06.30 The blood protein involved in blood coagulation is [KCET 2000] (1) Heparin (2) Prothrombin (3) Thrombin (4) All of these PR interval in a normal ECG, at heart beat of 70/min is approximately (1) 180 ms (2) 80 ms (3) 8 ms (4) 320 ms Bicuspid valve allows blood from [BHU 2000] (1) Right auricle to left ventricle (2) right auricle to right ventricle (3) left auricle to left ventricle (4) post caval to heart The difference between pulmonary arteries and veins is [CBSE 2000] (1) former is associated with lungs and later with heart (2) arteries have more thicker walls (3) veins are more elastic (4) veins have valves Purkinje fibres are found in [BHU ‘95, 2000] (1) Brain (2) Skin (3) Conduction system of heart (4) Nephrons of kidney

37.

38.

39.

40.

Hepatic portal system starts from [Punjab 2000] (1) Gut to liver (2) Kidney to liver (3) Liver to heart (4) Liver to kidney Which of the following animal heart has two pacemakers? [AIIMS 2000] (1) Amphioxus (2) Asterias (3) Herdmania (4) Balanoglossus In rabbit, oxygenated blood flows from [RPMT 01] (1) right ventricle to aorta during ventricular systole (2) left auricle of left ventricle during auricular systole (3) right auricle to right ventricle during ventricular systole (4) pulmonary vein to left auricle during auricular systole Myocardial Infarction is caused by [MAHE ‘01] (1) hardening of arteries (2) lumpy thickness develop in the inner walls of arteries (3) clot may occur in the lumen of a coronary artery

41.

42.

43.

44.

45.

46.

47.

(4) sudden interruption in blood flow towards a portion of heart Sinus venosus is present in [DPMT ‘01] (1) birds only (2) birds and mammals (3) reptiles and birds (4) fishes, amphibians and reptiles Which of the following cations is required for the conversion of prothrombin into active thrombin by thromboplastin? [Kerala ‘01] (1) Cu2+ (2) Fe3+ (3) Fe2+ (4) Ca2+ Which statement is correct about veins? They carry [MAHE ‘01] (1) deoxygenated blood (2) blood from all organs to heart (3) oxygenated blood (4) blood from heart to different organs. Closed blood vascular system occurs in [MAHE ‘01] (1) earthworm (2) housefly (3) cockroach (4) Leech During systole of heart [PCS ‘01] (1) only auricles contract (2) only ventricle contract (3) auricle and ventricles contract separately (4) auricles and ventricles contract simultaneously Which of the following carries blood rich in food materials, such as glucose and amino acids, from intestine to liver? [AIIMS ‘94; BHU ‘01] (1) Dorsal aorta (2) Mesenteric artery (3) Renal portal vein (4) Hepatic portal vein Hardening of the arteries due to deposition of cholesterol is called [KCET ‘02] (1) thrombosis (2) atherosclerosis (3) rhinitis (4) stenosis

BODY FLUIDS AND CIRCULATION 48.

49.

50.

51.

52.

53.

54.

55.

56.

57.

58.

59.

Pulmonary vein, carrying oxygenated blood, opens into [JIPMER ‘02] (1) Left auricle (2) Right auricle (3) Left ventricle (4) Right ventricle Papillary muscles are associated with [Vellore ‘02] (1) ventricles (2) auricles (3) dorsal aorta (4) sinus venosus One of the following blood vessel is without valves [BVP ‘02] (1) artery (2) pulmonary aorta (3) vein (4) systemic aorta Pulmonary artery carries [JIPMER ‘02] (1) deoxygenated blood from heart to lungs (2) deoxygenated blood from lungs to heart (3) oxygenated blood from heart to lungs (4) oxygenated blood from lungs to heart Resting membrane potential of individual mammalian cardiac muscle fibre is (1) –70 mV (2) –90 mV (3) –120 mV (4) –10 mV Pulse pressure is [BVP ‘02] (1) Systolic pressure (2) Diastolic pressure (3) Systolic pressure and diastolic pressure (4) Difference between systolic pressure and diastolic pressure Thromboplastin is secreted by [CPMT ‘96; Haryana ‘02] (1) platelets (2) lymphocytes (3) helper T cells (4) mast cells Four chambered heart is found in [RPMT ‘02] (1) cobra (2) tortoise (3) salamander (4) crocodile In mammals, veins differs from arteries in having (1) thicker walls [Orissa ‘02] (2) deeply present (3) carry blood away from heart (4) internal valves Carotid labyrinth contains [CPMT ‘02] (1) Olfactoreceptors (2) Baroreceptors (3) Chemoreceptors (4) phonoreceptors ECG records [BV Pune ‘03] (1) rate of heart beat (2) potential difference (3) ventricular concentration (4) volume of blood pumped Which one of the following is a matching pair? [AIIMS ‘03] (1) Lubb-Sharp closure of AV valves at the beginning of ventricular systole (2) Dup-Sudden opening of semilunar valves at the beginning of ventricular diastole (3) Pulsation of the radial artery-Valves in the blood vessels (4) Initiation of the heart beat -Purkinje fibres

713 60.

61.

62.

63.

64.

65.

In the heart of rabbit, the mitral valve is attached to the papillary muscles by [EAMCET ‘03] (1) bundle of His (2) Purkinje fibres (3) chordae tendinae (4) columnac carnac In evolution of animals, a heart to pump the blood is found for the first time in? [KPMT ‘03] (1) annelids. (2) flatworms (3) arthropods (4) echinoderms Which of the following has the thickest walls? [BHU ‘85; AIIMS ‘99; KCET ‘05] (1) Right ventricle (2) Left ventricle (3) Right auricle (4) Left auricle Which of the following substances, if introduced into the blood stream, would cause coagulation of blood at the site of its introduction? [CBSE’05] (1) Prothrombin (2) Fibrinogen (3) Thromboplastin (4) Heparin In adult man, normal BP is [CPMT ‘81, BHU ‘87, CBSE ‘98; Haryana ‘05] (1) 100/80 mm Hg (2) 120/80 mm Hg (3) 100/120 mm Hg (4) 80/120 mm Hg Which is the correct route through which pulse making impulse travels in the heart? [CBSE ‘95; Kerela ‘05] (1) SA node → AV node → Bundle of His → Purkinje fibres (2) AV node → Bundle of His → SA node → Purkinje fibres → heart muscles (3) AV node → SA node → Purkinje fibres → Bundle of His → heart muscles

66.

67.

68.

(4) SA node → Purkinje fibres → Bundle of His → AV node → heart muscles ‘Heart of Heart’ is [BHU ‘05] (1) SA node (2) AV node (3) bundle of His (4) purkinje fibres. What happens when the pacemaker is non functional ? [Kerala ‘05] (1) only the auricles will contract rhythmically (2) the cardiac muslces do not contract in a coordinated manner rhythmically (3) only ventricles will contract rhythmically (4) auricles and ventricles contract simultaneously. Find out the incorrect answer from the following? [Manipur ‘05] (1) veins are typically larger in diameter than arteries (2) because of their small size, capillaries contain blood that is moving more quickly than in other parts of the circulatory system (3) the walls of arteries are elastic, enabling them to stretch and shrink during changes in blood pressrue (4) veins contain more blood than any other part of the circulatory system

714 69.

70.

71.

72.

73.

74.

75.

76.

77.

78.

BIOLOGY How many times a red blood corpuscle will have to pass through the heart in its journey from hepatic artery to the aorta ? [KCET ‘05] (1) two times (2) only once (3) several times (4) four times Natural anticoagulant is [AMU ‘05] (1) heparin (2) serotonin (3) digitonin (4) erythromycin Mainfestation of increase in the blood pressure of a person is called [JK ‘05] (1) hypertension (2) atherosclerosis (3) arteriosclerosis (4) none of these To which organ does femoral artery supply blood? [Orissa ‘05] (1) dorsal part of thigh (2) all parts of hind limbs (3) ventral part of hind limbs (4) rectum Different factors play important roles in coagulation of blood, some of the factors are listed in list -I and their nomenclatures are given in list-II. Find out the accurate matching [Manipur ‘05] List -I List - II a factor II 1. Thromboplastin b factor III 2. Prothrombin c factor VIII 3. Hageman factor d factor XII 4. Antiheaemophilic globulin (1) a : 2, b : 1, c : 4, d : 3 (2) a : 1, b : 2, c : 3, d : 4 (3) a : 3, b : 4, c : 2, d : 1 (4) a : 4, b : 4, c : 2, d : 1 Sciatic vein of frog opens in [BHU ‘05] (1) heart (2) kidney (3) pelvic region (4) liver The vein that does not directly open into the heart is (1) Pre caval (2) Post caval [EAMCET ‘05] (3) Pulmonary (4) Posterior mesenteric How many double circulations are normally completed by the human heart, in one minute? [KCET ‘06] (1) eight (2) sixteen (3) seventh two (4) thirty six Maximum amount of oxygen is lost from the blood in the [KCET ‘06] (1) capillaries surrounding the tissue cells (2) arteries of the body (3) capillaries surrounding the alveoli (4) left auricle of the heart Closure of which of the following makes louder sound of heart beat? [GCET ‘06] (1) mitral valve (2) seminular valve (3) auriculo-ventricular valve (4) tricuspid valve

79.

80.

81.

82.

83.

84.

85.

86.

87.

In ECG, what does ‘T’ wave represent? (1) diastole of auricles [GCET ‘06] (2) diastole of ventricles (3) systole of ventricles (4) diastole of auricles and ventricles Arcuate (curved or arched) artery is found in (1) kidney (2) skin [Orissa ‘06] (3) lungs (4) all of these Which one is absent in man? [CPMT ‘06] (1) renal portal vein (2) hypophysial – hypothalamotract (3) hepatic portal vein (4) none of these The pacemaker of the human heart is [CBSE ‘94; CPMT ‘98, 2000; Kerala ‘01; Wardha ‘02; KCET ‘02; BHU ‘06] (1) SA node (2) tricuspid valve (3) AV node (4) SV node The opening of auricles into ventricles on the right side is guarded by valves [CET Chd. ‘99; HPMT ‘06] (1) Tricuspid (2) Bicuspid (3) Semilunar (4) Mitral valve Blood circulation that starts in capillaries and ends in capillaries is called [CPMT ‘06] (1) Portal circulation (2) Hepatic circulation (3) Lymphatic circulation (4) Renal circulation A drop of each of the following, is placed separately on four slides. Which of them will not coagulate? (1) Whole blood from pulmonary vein [CBSE ‘07] (2) Blood plasma (3) Blood serum (4) Sample from the thoracic duct of lymphatic system Consider the following statements about biomedical technologies: [CBSE ‘08] (a) During open heart surgery blood is circulated in the heart-lung machine (b) Blockage in coronary arteries is removed by angiography (c) Computerised Axial Tomography (CAT) shows detailed internal structure as seen in a section of body (d) X-ray provides clear and detailed images of organs like prostate glands and lungs Which two of the above statements are corect? (1) a and b (2) b and d (3) c and d (4) a and c In humans, blood passes from the post caval to the diastolic right atrium of heart due to: [CBSE ‘08] (1) pressure difference between the post caval and atrium (2) pushing open of the venous valves (3) suction pull (4) stimulation of the sino auricular node

BODY FLUIDS AND CIRCULATION 88.

89.

90.

91.

92.

93.

94.

In a standard ECG which one of the following alphabets is the correct representation of the respective activity of the human heart? [CBSE ‘09] (1) P-depolarisation of the atria (2) R-repolarisation of ventricles (3) S-start of systole (4) T-end of diastole If due to some injury the chordae tendinae of the tricuspid valve of the human heart is partially non-functional, what will be the immediate effect? [CBSE ‘10] (1) The flow of blood into the pulmonary artery will be reduced. (2) The flow of blood into the aorta will be slowed down (3) The ‘pacemaker’ will stop working (4) The blood will tend to flow back into the left atrium Arteries are best defined as the vessels which [CBSE’ 11] (1) Carry blood from one visceral organ to another visceral organ (2) Supply oxygenated blood to the different organs (3) Carry blood away from the heart to different organs (4) Break up into capillaries which reunite to form a vein ‘Bundle of His’ is a part of which one of the following organs in humans? [CBSE’ 11] (1) Pancreas (2) Brain (3) Heart (4) Kidney Which one of the following plasma proteins is involved in the coagulation of blood? [CBSE’ 11] (1) Fibrinogen (2) An albumin (3) Serum amylase (4) A globulin Which one of the following statements is correct regarding blood pressure? [CBSE’ 11] (1) 190/110 mmHg may harm vital organs like brain and kidney (2) 130/90 mmHg is considered high and requires treatment (3) 100/55 mmHg is considered an ideal blood pressure (4) 105/50 mmHg makes one very active Given below is the ECG of a normal human. Which one of its components is correctly interpreted below? [CBSE Final’ 11] R

P

Q

S

715 95.

96.

97.

98.

99.

In order for the blood to flow from right ventricle to left ventricle in mammalian heart, it must flow through [DPMT’ 10] (1) Right ventricle, Pulmonary arteries, Lungs, Pulmonary veins, Left atrium (2) Right ventricle, Pulmonary veins, Lungs, Pulmonary arteries, Left atrium (3) Right ventricle, Right atrium, Lungs, Pulmonary veins, Left atrium (4) Right ventricle, Systemic aorta, Lungs, Pulmonary veins, Left atrium Foramen ovale [DPMT’ 11] (1) Connects the two atria in the fetal heart * (2) Is a condition in which the heart valves do not completely close (3) Is a shallow depression in the interventricular septum (4) Is a connection between the pulmonary trunk and the aorta in the fetus To obtain a standard ECG, a patient is connected to the machine with three electrodes [DPMT’ 11] (1) One to each wrist and to the left ankle (2) One to each ankle and to the left wrist (3) One to each wrist and to the left chest region (4) One to each ankle and to the left chest region Figure shows schematic plan of blood circulation in human with labels A to D. Identify the label and give its function/s. [AIPMT (NEET)’13]

(1) A- pulmonary vein- takes impure blood from body parts, pO2 = 60 mm Hg (2) B- Pulmonary artery- take blood from heart to lungs, pO2 = 90 mm Hg (3) C- vena cava- takes blood from body parts to right auricle, pCO2 = 45 mm Hg (4) D- dorsal aorta- takes blood from heart to the body parts, pO2 = 95 mm Hg The diagram given here is the standard ECG of a normal person . The P- wave represents the [AIPMT (NEET)’13]

T

(1) Peak P and Peak R together - systolic and diastolic blood pressures (2) Peak P - Initiation of left atrial contraction only (3) Complex QRS - One complete pulse (4) Peak T - Initiation of total cardiac contraction

(1) (2) (3) (4)

Contraction of both the atria Initiation of the ventricular contraction Beginning of the systole End of the systole

716 100. Most of our cells are surrounded by [AMU’13] (1) Blood (2) Fluid equivalent to sea water in salt composition (3) Interstitial fluid (4) Pure water 101. Pulse is direct measure of: [AMU’13] (1) Blood pressure (2) Stroke volume (3) Cardiac output (4) Heart rate 102. Blood pressure in the mammalian aorta is maximum during: [AIPMT’15] (1) Systole of the left atrium (2) Diastole of the right ventricle (3) Systole of the left ventricle (4) Diastole of the right atrium 103. Doctors use stethoscope to hear the sounds produced during each cardiac cycle. The second sound is heard when: [RE-TEST AIPMT’15] (1) Ventricular walls vibrate due to gushing in of blood from atria (2) Semilunar valves close down after the blood flows into vessels from ventricles (3) AV node receives signal from SA node (4) AV valves open up 104. Which one of the following animals has two separate circulatory pathways? [RE-TEST AIPMT’15] (1) Lizard (2) Whale (3) Shark (4) Frog

BIOLOGY 105. Mitral valve in mammalian heart guards the opening between: [UP CPMT’15] (1) Pulmonary vein and left auricle (2) Right atrium and right ventricle (3) Left atrium and left ventricle (4) Left ventricle and dorsal aorta 106. Choose the correct statement: [AMU’15] (1) Stroke volume multiplied by cardiac output gives the heart rate (2) Heart rate multiplied by cardiac output gives the stroke volume (3) Cardiac output divided by heart rate gives the stroke volume (4) Stroke volume divided by heart rate gives the cardiac output 107. Incomplete double circulation is seen in: [KERALA’15] (1) Fish (2) Amphibians (3) Birds (4) Mammals 108. Choose the correct statement among the followings: [KERALA’15] (1) Atrioventricular node is the pace maker that generates action potential and initiates the atrial systole (2) During each cardiac cycle, the ‘Lub’ sound is due to the closure of semilunar valves (3) Stroke volume in each cardiac cycle has approximately 170 ml of blood (4) QRS complex in an ECG indicates depolarization of ventricles

BODY FLUIDS AND CIRCULATION

717

EXERCISE - 3 | Test Yourself 1. 2. 3.

4. 5.

6.

7.

8. 9.

10. 11.

Pulmonary artery arises from (1) Right atrium (2) Left atrium (3) Right ventricle (4) Left ventricle Opening of following is guarded by Thebesian valve (1) Post caval vein (2) Foramen ovale (3) Coronary Sinus (4) Pulmonary arch Fishes have (1) Open and single circulatory system (2) Open and double circulatory system (3) Closed and single circulatory system (4) Closed and double circulatory system Myogenic heart is present in(1) Mollusca (2) Pisces (3) Mammalia (4) All of these Sinu-atrial node in human heart is embedded in the wall of (1) Sinus-venosus (2) Interatrial septum (3) Right atrium (4) Atrioventricular septum If a segment of brachial artery carries 40 ml of blood during left ventricular diastole, then the amount of blood present in the same segment during left ventricular systole will be (1) 40 ml (2) 20 ml (3) 60 ml (4) 80 ml Which of the following set of events can occur simultaneously (1) Auricular depolarization, Ventricular depolarization, Auricular systole (2) Ventricular depolarization, Auricular systole, Ventricular diastole (3) Auricular depolarization, ventricular repolarization, Auricular diastole (4) Auricular depolarizaion, ventricular diastole, Auricular systole. Pace maker is the bundle of (1) Smooth muscles (2) Nerve fibres (3) Cardiac muscles (4) None of these Which of the following animal has maximum heart beats per unit time (1) Whale (2) Camel (3) Rat (4) Tortoise Papillary muscles are associated with (1) Atria of heart (2) Ventricles of heart (3) Walls of Aorta (4) None of these First sound of heart beat is of lower frequency and longer duration. It develops during (1) Opening of bicuspid and Tricuspid valve (2) Closing of bicuspid and Tricuspid valve (3) Opening of semi lunar valves (4) Closing of semi lunar valves.

12. 13.

14.

15.

16. 17.

18.

19. 20. 21.

22.

Which organ receives only oxygenated blood (1) Liver (2) Pancreas (3) Kidney (4) Gills Which of the following is a false statement : (1) All systemic veins carry deoxygenated blood (2) All veins carry blood towards the heart (3) In foetal circulation, pulmonary vein carries pure blood (4) The amount of blood present in an artery during ventricular systole is 150% of the amount of blood present in the same artery during ventricular diastole. Open blood vascular system without haemoglobin is found in (1) leech (2) Hydra (3) cockroach (4) Both (1) & (3) Myocardial ischemia causes (1) Rheumatic heart disease (2) Coronary Thrombosis (3) Heart block (4) Angina Pectoris Blood pressure is measured at (1) Radial vein (2) Radial artery (3) Brachial artery (4) Systemic aorta Which of the following statement regarding arteries is correct without exception? (1) They contain valves (2) They have broader lumen (3) Carry blood away from the heart (4) All of these Mark the correct statement about Renal Portal System (A) and Hepatic Portal System (B) (1) Frog has A but lacks B (2) Rabbit has A but lacks B (3) Both lack A (4) Both have B Which of the following is an unpaired artery? (1) Coeliac (2) Carotid (3) Pulmonary (4) Renal Effect of acetylcholine on heart is (1) Tachycardia (2) Bradycardia (3) Arrhythmia (4) Myocardial infarction The other name for stroke Adam’s syndrome is (1) Heart attack (2) Heart fail (3) Ventricular escape (4) Rheumatoid heart disease Heart of fishes does not have (1) Sinus venosus (2) Interatrial septum (3) Deoxygenated blood (4) One ventricle

718 23. 24.

25.

BIOLOGY A local abnormal dilation of an artery is called (1) Arteriosclerosis (2) Aneurysm (3) Varicose (4) Atherosclerosis Pulmonary vein (1) Collects impure blood from the lungs (2) Collects impure blood from the right atrium for supplying the lungs (3) Pours pure blood into right atrium (4) None of these is true During joint diastole (1) Both semilunar valves and atrio-ventricular valves remain open

35.

36.

37.

(2) Blood flows into and from atria to ventricles

26.

27. 28.

29. 30.

31.

32. 33.

34.

(3) Blood flows both into pulmonary and systemic aorta (4) None of these is true A.V. Node in human heart is embedded in (1) Inter-atrial septum (2) Inter-ventricular septum (3) The wall of right atrium closer to precaval opening (4) Atrio-ventricular septum Normal cardiac output of human beings is (1) 5 litres/ minute (2) 1 litre/minute (3) 100ml/minute (4) 70 ml/minute Coronary sinus (1) Drains impure blood from pulmonary veins to left atrium (2) Receives impure blood from heart musculature via coronary veins. (3) Drains pure blood into right atrium (4) Both (2) and (3) correct Mark the odd one out (1) Pulmonary vein (2) Precaval (3) Renal vein (4) Thoracic duct Systemic heart refers to (1) Two ventricles together in human (2) The heart that contracts under the stimulation of nervous system (3) Left atrium and left ventricle in higher vertebrates (4) Entire heart in lower vertebrates If there is blockage in thoracic duct, the lymph gets accumulated resulting into oedema in the following part (1) Right arm (2) Right and left legs (3) Left arm (4) Both (1) and (2) The maximum arterial blood flows to (1) Kidney (2) Heart (3) Liver (4) Brain Ductus arteriosus in foetus (1) Arises from left ventricle (2) Arises from right ventricle (3) Connects systemic and pulmonary aorta (4) Connects right and left atria Which vein carries blood away from an organ and ends in other organ instead of vena cava or right atrium (1) Hepatic vein (2) Renal vein (3) Portal vein (4) Coronary vein

38.

39.

40.

41.

42.

43.

44.

45.

If a person is loosing blood continuously due to injury then the effect on his pulse and BP will be initially (1) Pulse and BP both will fall (2) Pulse will fall and BP will rise (3) Both pulse and BP will rise (4) Pulse will rise and BP will fall. In neurogenic heart the secretion of acetylcholine (1) Increases heart beat (2) Decreases heart beat (3) Produces no effect (4) Is absent Tricuspid valve prevents the flow of blood from (1) Left atrium to left ventricle (2) Right atrium to left ventricle (3) Left ventricle to left atrium (4) Right Ventricle to right atrium In Heart-block (1) Coronary artery is narrowed and blood supply to heart muscles is reduced (2) Coronary artery is blocked (3) Time gap between atrial and ventricular systole is increased (4) Ductus arteriosus persists The interval period of heart rest in ECG is represented by the following (1) PQ wave (2) T wave (3) ST wave (4) TP wave Following blood vessels help in regulating the blood pressure and the amount of blood flowing to the tissues (1) Capillaries (2) Veins (3) Arterioles (4) Venules Coronary sulcus is the other name for (1) Interatrial groove (2) Interventricular groove (3) Atrioventricular groove (4) Interventricular septum In ECG the elevation of ST- segment indicates (1) Acute myocardial infarction (2) Insufficient supply of oxygen to the heart muscles (3) Inflammation of atria (4) Rheumatic heart disease In human heart, which of the following valve remains in contact of the oxygenated blood only? (1) Tricuspid valve (2) Semi lunar valve (3) Eustachian valve (4) Mitral valve Sinus venosus in frog’s heart (1) Opens into right atrium (2) Sends blood to dorsal aorta (3) Is situated on ventral side (4) All of these Hirudin (anticoagulant) is (1) Present in the blood of the mammals (2) Present in the blood of leech (3) Secreted by the mast cells of the human blood (4) Present in saliva of certain annelids

BODY FLUIDS AND CIRCULATION

719

ANSWER KEY EXERCISE 1 : NCERT BASED QUESTIONS 1. 6.

(4) (3)

2. 7.

(3) (3)

3. 8.

(4) (1)

4.

(2)

5.

(4)

EXERCISE 2 : WINDOW TO COMPETITIVE EXAMS 1. 6. 11. 16. 21. 26. 31. 36. 41. 46. 51. 56. 61. 66. 71. 76. 81. 86. 91. 96. 101. 106.

(4) (4) (3) (4) (4) (1) (4) (3) (4) (4) (1) (4) (1) (1) (1) (3) (1) (4) (3) (1) (4) (3)

2. 7. 12. 17. 22. 27. 32. 37. 42. 47. 52. 57. 62. 67. 72. 77. 82. 87. 92. 97. 102. 107.

(2) (4) (1) (1) (2) (1) (2) (1) (4) (2) (2) (2) (2) (2) (1) (1) (1) (1) (1) (1) (3) (2)

3. 8. 13. 18. 23. 28. 33. 38. 43. 48. 53. 58. 63. 68. 73. 78. 83. 88. 93. 98. 103. 108.

(3) (1) (4) (4) (2) (4) (1) (3) (2) (1) (4) (2) (3) (2) (1) (3) (1) (1) (1) (3) (2) (4)

4. 9. 14. 19. 24. 29. 34. 39. 44. 49. 54. 59. 64. 69. 74. 79. 84. 89. 94. 99. 104.

(3) (3) (1) (4) (3) (2) (3) (2) (1) (1) (1) (1) (2) (1) (3) (4) (1) (1) (3) (1) (2)

5. 10. 15. 20. 25. 30. 35. 40. 45. 50. 55. 60. 65. 70. 75. 80. 85. 90. 95. 100. 105.

(1) (3) (4) (3) (1) (2) (2) (4) (3) (1) (4) (3) (1) (1) (4) (1) (3) (3) (1) (3) (3)

EXERCISE 3 : TEST YOURSELF 1. 2.

(3) (3)

3.

(3)

4.

(4)

5. 6.

(3) (3)

7.

(4)

It carries deoxygenated blood. From coronary sinus the deoxygenated blood is collected into right atrium. The oxygenated blood from gills, in fishes, directly goes to the organs. In such hearts the heart beat is generated by specialized cardiac muscles. SAN in right atrium is close to Precaval. Blood in a segment of artery in ventricular systole is 150% of ventricular diastole. (Compare systolic and diastolic pressures, i.e. 120 : 80).

8.

(3)

These cardiac muscles do not have the function of

9.

(3)

Smaller the animal greater is the BMR.

10.

(2)

Chordae tendinae on one side are attached to flap

contraction, but conduct nerve impulse.

of the atrio-ventricular valve and on the other with the papillary muscles. 11.

(2)

Second sound is produced during closing of semilunar valves.

12.

(2)

Liver receives deoxygenated blood from hepatic portal vein and kidney receives deoxygenated blood from renal portal vein (frog).

13.

(3)

14.

(3)

In all insects the respiratory pigment is lacking.

15.

(4)

In this case blood supply to the heart muscles is reduced.

16.

(3)

Brachial artery arises from subclaviam artery

17.

(3)

Arteries have narrow lumen and do not have valves.

18.

(4)

Renal portal system is absent in rabbit.

19.

(1)

20.

(2)

Bradycardia is slowing of heartbeat. Tachycardia develops in the presence of adrenaline.

21.

(3)

22.

(2)

In fishes the heart is two- chambered only (1A + 1V).

23.

(2)

Varicose is the dilation of vein in which the permeability increases.

24.

(4)

Pulmonary vein collects pure blood from lungs and pours it into left atrium.

25.

(2)

The duration of joint diastole is 0.4 seconds.

26.

(1)

This node is located close to the tricuspid valve

27.

(1)

28.

29.

(4)

Thoracic duct is the lymphatic duct (major). The

(2)

rest three are blood vessels. 30.

(3)

Both have oxygenated blood for systemic circulation.

31.

(3)

Thoracic duct is the major lymphatic duct of left hand side.

32.

(1)

Though the maximum blood (1500 ml) flows to liver but arterial blood is only 500ml (the rest is from hepatic portal vein). The arterial blood supply in kidney is 1250 ml per minute.

720

BIOLOGY

33.

(3)

34.

(3)

35. 36.

(4) (1)

37.

(4)

38. 39. 40.

(3) (4) (3)

This closes at the time of birth because the lungs become functional. Hepatic portal vein pours blood into liver, whereas Renal portal vein pours blood into kidney. In myogenic heart, the secretion of acetylcholine decreases the heart beat. Tricuspid valve allows the flow of blood from right atrium to right ventricle. In heart block the PR lengthens in ECG. In the walls of arterioles elastic tissue is less but

the smooth muscles are more and are innervated by nor- adrenergic fibres. A small change in the caliber of arterioles causes a large change in the peripheral resistance. 41. 42.

(3) (1)

43.

(4)

44.

(1)

45.

(4)

Like heart block, in Rheumatic heart disease also, the PR segment lengthens. Semi-lunar valve of pulmonary aorta is in contact of deoxygenated blood. The sinus venosus brings deoxygenated blood to right atrium. It is absent in human.

19

Chapter

Excretory Products and their Elimination Excretory Products and their Elimination While going through the chapter pay special attention to the following – Terms and definitions1. High threshold substances 3. Counter current mechanism

2. 4.

Uremia Phenylketonuria

Differences1. Ureotelic and uricotelic 2. Osmoregulator and osmoconformer 3. Mesonephros and metanephros kidney 4. Cortical nephron and Juxtamedullary nephron 5. Glycosuria and diabetes mellitus 6. Hyperionic and hyperosmotic Relationships1. Arginase and urea synthesis 2. Excretory product and surrounding environment Structures with functions – 1. Solenocytes 3. Podocyte layer 5. Filtration membrane 7. Ionocytes

2. 4. 6.

Green glands Brush- border epithelium Vasa recta

Numerical values – 1. Net filtration pressure 3. Blood urea

2.

Osmolarity of body fluids

Excretion is the removal of metabolic waste (mainly) from the body. Faecal matter is undigested waste, and not metabolic waste, so it is not considered as excretory product. The excretory wastes are of two types. (1) Non-nitrogenous wastes− •

Carbon-di-oxide- It is removed through lungs (accessory excretory structure).

•

Excess water and excess salts are removed through kidney (primary excretory structure).

At a Glance 

Excretory wastes

 

Non-nitrogenous wastes Nitrogenous wastes



Excretory structures in nonchordates



E xc re to r y s t r u c t u re s i n vertebrates



Excretory system in human

  

Nephron (uriniferous tubule)

Urine formation

Disorders of Excretory system

722

BIOLOGY (2) (i)

Nitrogenous wastes− Such wastes are produced from the metabolism of proteins and nucleic acids. Ammonia (NH3)−

•

The animals in which ammonia is the major excretory product are called Ammonotelics.

•

Ammonia is about 1−lakh times more toxic than urea.

•

(ii)

Removal of ammonia requires plenty of water. It is, therefore, the excretory product in aquatic animals. eg. protozoans, porifers, coelentrates, aquatic molluscs, aquatic crustaceans, aquatic insects, platyhelminthes, protochordates, teleosts (bony fishes) and aquatic amphibians. In fishes most of the Ammonia is lost as Ammonium ions (NH4+) through the gills. The kidney in such animals plays a minor role in the excretion of Ammonia. Urea −

•

The animals in which urea is the major excretory product are called Ureotelics.

•

Urea is less toxic and requires less water for elimination.

•

Most of the amphibious animals, therefore, have urea as the major excretory product. eg Cartilaginous fishes (marine), Amphibians (amphibious), Reptiles (amphibious, like turtle) and all mammals (aquatic, amphibious or terrestrial). Sharks also produce urea but retain a major part of it as osmolyte for maintaining osmolarity of their body fluid. ARGININE Arginase (enz.)

Fumarate

KREB'S CYCLE

+H 2O

+ NH 3

ARGINO-SUCCINATE

Ornithine cycle or Krebs -Henseleit cycle

UREA

– H2O Aspartate CITRULLINE

ORNITHINE

Fig. 19.1 : Urea synthesis cycle

Connecting Concepts  Hepatic vein, that collects blood from the liver, has maximum urea. The renal vein, that arises from kidney, has minimum urea.

•

Urea is produced in liver through Krebs−Hansleit cycle, also known as Ornithine cycle.

•

Three important amino acids − Arginine, Ornithine and Citrulline, participate in urea synthesis.

• Arginase (enzyme), present in liver, is essential for urea synthesis. (iii) Uric acid− •

The animals in which uric acid is the major excretory product are called Uricotelics.

EXCRETORY PRODUCTS AND THEIR ELIMINATION

723

• •

Uric acid is least soluble in water and can be stored as a solid waste. It can be removed from the body without the loss of water. eg. Insects, Land snails, Lizards and Birds. Such animals have adaptations for water conservation. Crocodile, besides uric acid, also excretes ammonia. (iv) Allantoin • This excretory product is present in non−primates and is absent in human. It is formed Connecting Concepts from uric acid.  Primates include lemurs, loris, (v) Hippuric acid− tarsier, monkeys, apes and human. • It is formed from benzoic acid and is the excretory product of all mammals. (vi) Ornithuric acid− • It is also formed from benzoic acid and is the excretory product in birds. (vii) Trimethyl amine oxide (TMO)− • It is the excretory product in marine bony fishes. (viii) Guanine− • It is the excretory product in spiders. (ix) Creatinine− • It is formed in liver from Creatine phosphate (an energy rich compound in skeletal muscles). Its normal amount in human urine is 1.5 mg/100 ml of urine. During muscle injury its amount increases in the urine. (x) Bile pigments− • This excretory product is formed in liver from the haem of haemoglobin. • The major bile pigment is bilirubin. • Bile pigments are released into intestine through bile juice. •

Bilirubin is toxic and its concentration increases during Jaundice.

EXCRETORY STRUCTURES IN NON-CHORDATES  

   

 



In protozoans, porifers and coelenterates the specialised excretory structures are absent. The excretion in these animals occurs through general body surface. In Platyhelminthes (flat worms) the excretory structures are Protonephridia or Solenocytes. These structures are also present in Rotifers, Cephalochordates (Amphioxus). and some annelids. In annelids the excretory structures are nephridia. In molluscs the excretion occurs through Metanephridia or ‘Organ of Bojanus’. In arthropods there are different type of excretory structures. In crustaceans (crab, prawn, cray fish etc.) the excretory organs are green glands or antennal glands (seated at the base of antenna). A green gland contains coelomosac, labyrinth, nephridial duct, bladder and nephridiopore. In arachnids (scorpion, spider etc.) the excretory structures are coxal glands. In insects the excretory structures are Malpighian tubules. In Cockroach these tubules are attached in between midgut and hindgut. The excretory product in cockroach, like other terrestrial insects, is uric acid.

Connecting Concepts  The contractile vacuoles present in fresh water protozoans are the osmoregulatory structures and regulate osmotic concentration (osmolarity) of the body. Though some ammonia is also lost through contractile vacuoles, but they can not be considered as excretory structures.

Connecting Concepts

 The tubules of protonephridia in flatworms terminate into Flame cells. These cells contain tuft of cilia which project into the tubule and beat like flickering (candle) flame, hence the In echinoderms the excretory system is absent and excretion occurs through Nephrocytes name – Flame cells.

(a type of amoebocytes). . . . .... . . ....... ....................... ........... .. ............... . .......... . .. contractile ....... ....................... vacuole .... .............. . ..... ... ...... . .. ... . ........ ... .......... ... diffusion ...................................... ....... . ............................ .. ... .. ....... ................. .... AMOEBA

flame cell

segmental nephridia

Malpighian tubules

cilia midgut

body cells HYDRA

excretory duct PLANARIA

hindgut

Nephridia EARTHWORM

Fig. 19.2 : Excretory Structures in Non-chordates

INSECT

724

BIOLOGY

EXCRETORY STRUCTURES IN VERTEBRATES In all vertebrates the primary excretory structure is kidney.The structural and functional unit of kidney is Nephron or uriniferous tubule. The kidneys are of three types Pronephros kidney 1.

Nephrons (uriniferous tubules) are

Mesonephron kidney 1.

segmentally arranged.

Nephrons are not segmentally

Metanephros kidney 1.

arranged

Nephrons are not segmentally arranged.

2.

Glomerulus –external

2.

Glomerulus –internal

2.

Glomerulus – internal

3.

Nephrostome* present and

3.

Nephrostome present or

3.

Nephrostome absent.

4.

It is posterior kidney

5.

It is differentiated into cortex

functional

absent. If present, then nonfunctional

Check Point 1. Answer the followings : (i) Which of the excretory product in human is most toxic? (ii) What are 3-important amino acids which participate in ureasynthesis cycle? (iii) What is the excretory product in bile juice? (iv) Which group of animals has coxal glands as excretory organs? (v) What is the function of contractile vacuole in Paramecium? (vi) What is the structural and functional unit of human kidney? (vii) Which enzyme of liver participates in ornithine cycle? (viii) In which type of kidney the nephrostomes are functional? (ix) What is the major excretory product in cockroach? (x) What type of kidney is present in tadpole?

4.

Commonly called ‘Head Kidney’

4.

(present in anterior side of body). 5.

Kidney is not differentiated into

Commonly called ‘Middle Kidney’

5.

cortex and medulla.

Here also, it is not differentiated into cortex and

and medulla.

medulla. 6.

The duct arising from kidney is

6.

Duct of this kidney is called

6.

Mesonephric duct or Wolffian

called Pronephric duct.

Duct of such kidney is called Metanephric duct or Ureter.

duct. 7.

PCT, Henle’s loop and DCT are

7.

Same as in Pronephros.

7.

not differentiated.

PCT, Henle’s loop and DCT are very well differentiated.

eg. Adults- Myxine (hag fish).

eg. Adults – Fishes and

e.g. Adults – Reptiles, birds

Embryos – Fishes and amphibians

amphibians. Embryos –

and mammals (not present in

(tadpole larva of frog)

Reptiles, birds and mammals.

embryonic stages).

In Cartilaginous fishes the tubules of kidney and gonads are fused. As the posterior part has kidney tubules, such kidney is called Opisthonephros ( opistho – behind).

EXCRETORY SYSTEM IN HUMAN 

Except urinary bladder which is endodermal in origin, the whole excretory system is mesodermal.



In human the kidney is retroperitoneal i.e., the kidney is located outside coelomic cavity and is covered by peritoneum (coelomic epithelium) from ventral side only.



The size of each kidney is ~10 cm and it weighs is ~150 g.



The two kidneys are assymmetrical, the Rt. being posterior to the Lt.



Each kidney is bean shaped with a groove (hilus) in the middle. The hilus is absent in frog’s kidney.



The white fibrous connective tissue-covering around kidney is called renal or fibrous capsule.



Each kidney (Metanephros type) is differentiated into 2 −regions: (1) Outer − cortex (2) Inner− medulla



At certain points the cortex extends into medulla forming ‘Columns of Bertini’.



Medulla contains 4−14 pyramids, each extending into pelvis.



The tip of pyramid is called papilla, and the major collecting duct (Duct of Bellini) opens at this point.



The spaces, larger and smaller, into which pyramids open are called major and minor calyx.

* Nephrostome – Mouth of nephron that opens into coelomic cavity.

EXCRETORY PRODUCTS AND THEIR ELIMINATION

725

Posterior vena cava Nephron units are located at the base of the renal pyramids

Medulla

Dorsal aorta Left kidney

Cortex

Renal artery

Hilus Renal vein Renal artery

Renal pyramid

Renal vein

Ureter Renal papilla

Urinary bladder Renal pelvis Ureter Urethra (A)

(B)

Fig. 19.3 : (A) Excretory system (Human), (B) Internal structure of human kidney

Nephron (uriniferous tubule)− As mentioned above, the Nephron is the structural and functional unit of kidney. The nephrons in human are of 2−types: (1)

Cortical nephrons •

About 85% of the nephrons are of such type.

Connecting Concepts

•

The glomeruli of these nephrons are present in outer cortex.

•

The Henle’s loop in these nephrons is shorter.

•

Vasa recta is lacking. C O R T E X

Cortical nephron Juxtamedullary nephron

M E D U collecting L duct L A

Vasa recta loop of Henle

Fig. 19.4 : Cortical and juxtamedullary nephrons

(2)

Juxtamedullary nephrons •

About 15% of the nephrons are of such type.

•

The glomeruli of these nephrons are present in the inner cortex.

•

The Henle’s loop in these nephrons is longer.

• Vasa recta is well developed developed. Each nephron consist of the following prominent parts. (1) Bowman’s capsule− •

It is a double walled and blind (closed) structure. The inner side of this capsule has modified squamous epithelial layer (podocyte layer).

•

Inside the capsule there is a bunch of capillaries (all arterial in nature) called Glomerulus. These capillaries (number ranging from 20 to 40) are more permeable than other capillaries of the body, due to the presence of fine endothelial pores ( (fenestrae ). These capillaries arise from Afferent arteriole (more in diameter) and join to form Ef Efferent arteriole (lesser in diameter).

 There are 2−types of capillariesnetworks around Henle’s loop: (1) Peritubular capillary network (2) Vasa recta. The Peritubular capillary network is present around both the limbs of Henle, in both type of nephrons. Erythropoetin hormone of kidney is secreted from the lining of this capillary network.  Vasa recta is present around individual limb of Henle and is present only in the Juxtamedullary nephrons.

726

BIOLOGY •

(The glomerulus along with Bowman’s capsule is called Malpighian body or Renal Corpuscle)

•

The endothelial lining of glomerular capillaries with basement membrane and podocyte layer of Bowman’s capsule, form Filtration membrane. Efferent arteriole collecting Afferent arteriole duct C DCT O Podocyte layer R T E .. .. X .. .. Microvilli PCT Thick ascending limb

. . .

M E D U L L A

.. .. .. ..

. . .

Collecting Duct

Descending Limb

Thin ascending limb

Papilla

Fig. 19.5 : Structure of Nephron with histological details

Endothelial pores (~ 10 nm) Endothelial cell (of Glomerular capillaries) F I L T R A T I O N

P A T H W A Y

Basement Membrane Bowman's capsule

Process of Podocyte Filtration slits (~ 25 nm) Fig. 19.6 : Diagrammatic representation of Filtration membrane

(2)

(3)

Proximal convoluted tubule (PCT) − •

It is lined with columnar epithelium, though the cells, due to presence of microvilli (not cilia), appear to be cuboidal.

•

This specialised epithelium of PCT is called Brush border epithelium. It increases surface area for absorption.

Henle’s Loop− •

It is Hair-pin like and has 2−limbs − Descending limb and Ascending limb.

•

The Descending limb of Henle is lined with flat cells (simple squamous epithelium). This epithelium is permeable to water but impermeable to sodium chloride (salts).

•

Ascending limb of Henle is lined with cubical or cuboidal cells (particularly the thick portion). This lining is permeable to sodium but impermeable to water.

•

The vasa recta, present around Henle’s loop of Juxta medullary nephrons, is absent in the Cortical nephrons.

EXCRETORY PRODUCTS AND THEIR ELIMINATION (4)

(5)

727

Distal convoluted tubule (DCT) − •

It is lined with cuboidal epithelium. The cells of this epithelium do not have well developed microvilli.

•

ermeability of this epithelium can be altered by the action of Aldosterone and Vasopressin (ADH) hormones.

Collecting tubule – The collecting tubules of different nephrons join to form collecting duct. The water absorption occurs both from, tubule and ducts.

URINE FORMATION 3−steps are involved in the formation of urine (A) Ultra filtration − •

It is filtration under pressure.

•

Glomerular capillary pressure (45 mm of Hg) favours filtration.

•

The Colloidal osmotic pressure (due to plasma proteins, particularly albumin) acts against filteration. Its value is ~20 mm of Hg.

•

The Capsular filtrate pressure, due to the glomerular filtrate in the Bowman’s capsule, also acts against filtration. Its value is ~10 mm of Hg. Net filtration pressure = 45 − (20+10) mm of Hg = 15 mm of Hg or 10 − 20 mm of Hg.

•

Only 1/5 of plasma (20%) gets filtered from glomerulus per unit time. It is about 125 ml per minute. Amount of glomerular filtrate = 125 ml / min = 7.5 litre/hr = 180 litre/day

The amount of urine formed per day is ~1.8 litre, i.e. 1% of 180 litre per day, which Connecting Concepts means that 99% of glomerular filtrate is reabsorbed.  Blood flow to both the kidneys is 1250 ml per minute and the amount of Autoregulation of glomerular filtration rate –

plasma (55% of it) is, therefore, ~650 ml. (125 ml of glomerular filtrate is 1/5 of 650 ml of plasma). This amount Myogenic System (1/5 or 20%) of glomerular filtrate is When BP is high the stretching of afferent arteriole is increased. This stimulates ‘stretch called ‘Filtration fraction’ and can be represented as receptors’ of the arteriole, and the diameter of afferent arteriole is reduced

2-mechanism of autoregulation – (1)

Atrial natriuretic factor (ANF), a hormone secreted from heart (atrium), promotes the loss  GFR (Glomerular filtration rate) RPF (Renal plasma flow) of sodium in urine and also reduces B.P. (2)

Renin-angiotensin-aldosterone system (RAAS) Juxta glomerular apparatus – The wall of afferent arteriole contains the renin-secreting juxta-glomerular cells (JGC). At this point the epithelium of distal tubule is histologically modified to form Macula densa (MD). The JGC, MD and adjoining granulated cells collectively form Juxta glomerular apparatus (JGA). When BP is low, the JG cells secrete renin. This converts Angiotensinogen protein of blood plasma, produced from liver, into Angiotensin I and then Angiotensin II. Angiotensin II is vasoconstrictor and increases BP. Angiotensin II also stimulates Adrenal Cortex for the secretion of Aldosterone, the latter absorbs Sodium from glomerular filtrate and raises BP. Aldosterone is antagonistic to Atrial Natriuretic factor-ANF.

728

BIOLOGY Juxta-glomerular cells Afferent arteriole

Macula densa

Efferent arteriole

DCT

Renal corpuscle

Glomerular epithelium Fig. 19.7 : Juxta glomerular apparatus

Composition of glomerular filterate− The glomerular filterate is Plasma minus proteins. It consists of 1. Glucose 5. Vitamins 9. Creatinine 2. Amino acids 6. Urea 10. Bicarbonates 3. Water 7. Uric Acid 11. Phosphates etc. 4. Salts 8. Hippuric Acid The concentration of glucose in glomerular filtrate is equal to its concentration in blood plasma. (B) Selective reabsorption (a) In PCT− The maximum reabsorption from glomerular filtrate occurs in this part. •

Glucose and amino acids are absorbed (100%) by active transportation.

•

[Active transportation requires energy (ATPs) and is against concentration gradient.]

•

Absorption of water is 60−70% (obligatory absorption).

•

Absorption of salts (sodium) also ranges from 60−70%. The absorption of chloride is however, passive.

•

Absorption of urea is ~50% while absorption of uric acid is ~95% (later added into glomerular filtrate by tubular secretion).

•

Creatinine and sulphates are not at all reabsorbed.

Check Point 1. Fill in the blanks with suitable words/ statements: (i) ..............% of glomerular filtrate is reabsorbed. (ii) Juxta glomerular apparatus is formed by .............. and .............. . (iii) .............. part of plasma is not filtred as glomerular filtrate. (iv) .............. limb of Henle’s loop is permeable for water. (v) .............. (Hormone) promotes the loss of sodium in urine.

• The absorption of bicarbonates and phosphates is more than 90%. High Threshold Substances− eg. Glucose and amino acids These substances are completely reabsorbed from the glomerular filtrate and do not appear in urine in normal conditions. Such substances appear in urine only when their concentration reaches beyond renal threshold. (For glucose threshold value is 170-180 mg/100 ml of blood plasma). Low Threshold Substances− eg. Urea and Uric acid These substances are not completely reabsorbed from the glomerular filtrate and, therefore, appear in urine in normal conditions. (b) In Henle’s Loop− The glomerular filtrate in Henle’s loop flows in opposite direction and parallel, in descending and ascending limbs. This mechanism is called Counter current mechanism/system which makes the fluid more concentrated. In fact there are 2−counter current mechanisms (i) Counter current multiplier (in Henle’s loop). (ii) Counter current exchanger (in Vasa recta)

EXCRETORY PRODUCTS AND THEIR ELIMINATION

729

Counter Current Mechanism The Counter Current Mechanism is the process in which inflow runs parallel and opposite but in the close proximity to the outflow for some distance. The osmolarity of plasma or the interstitial fluid in body parts is about 300m Osm/lit whereas the osmolarity in the interstial fluid in medulla (Medullary interstitium) of kidney is (progressively) much higher, i.e. about 1200m Osm/lit. This means that renal Medullary interstitium has accumulated solutes in great excess of water. Once this high solute concentration is achieved in medulla it is maintained by balanced inflow and outflow of solutes and water. 1. The Loop of Henle acts as ‘counter current multiplier’ by producing concentration gradient of high osmolarity in medullary interstitium. 2. The Vasa Recta acts as ‘counter current exchanger’ by maintaining or preserving this high solute concentration in medulla. The main cause of high medullary osmolarity is the active transport of sodium (and co-transport of potassium, chloride and other ions) from thick ascending loop of Henle into the interstitium. Since this ascending limb is impermeable to water, the solutes pumped out is not followed by osmotic flow of water into interstitium. This pump establishes a concentration gradient of about 200m Osm/lit between tubular lumen and interstitial fluid. The descending limb of Henle’s loop, in comparison to ascending limb is highly permeable to water, hence the water diffuses out into interstitium and the osmolarity of tubular fluid (of descending limb) quickly becomes equal to the medullary osmolarity. These steps are repeated over and over, and the net effect is the addition of more and more solute to the medulla in excess of water. Thus the trapping of solute due to active pumping out of ions out of thick ascending limb of Henle, gradually multiplies the concentration gradient, which eventually raises the osmolarity at the tip of the loop to ~1200m Osm/lit. (This repetitive re-absorption of sodium from the thick ascending limb of loop of Henle and the continuous inflow of new sodium chloride from PCT is ‘counter current multiplication’). Medullary interstitium 300 H2O

350 solute 350

350

150

⇒

Diffusion

Active transport

300

350

150

300

150

700

700

500 600

450

450 H2O 500

solute

solute

500

Ascending limb

Descending limb of vasa recta 1000

250

1000

800

solute

600 Ascending limb of vasa recta

H2O solute 800

800 H2O

⇒

H2O

⇒

Descending limb

300 H2O

solute 1200

300

1200 1200

Early stage

1000

1000

1000

1200

Final stage (A)

(B)

Fig. 19.8 : (A) Counter current multiplier system in loop of Henle (Numerical values are of Osmolarity in mOsm/lit), (B) Counter current exchange in vasa recta The Vasa Recta, a capillary network around individual limb of Henle’s loop, acts as counter current exchanger and preserves the high solute concentration in medullary interstitium. As blood (in Vasta Recta) descends into medullary region it progressively becomes more concentrated, partly by loss of water into interstitium and party by solute entry from the medullary interstitium into Vasa Recta. By the time the blood reaches the tip of Vasa Recta it has concentration of about 1200m Osm/lit, the same as in medullary interstitium. Now, as the blood ascends towards the cortex it becomes less concentrated because the solute diffuses out into interstitium and the water moves into this part of Vasa Recta. Thus, there is a large amount of fluid-and-solute exchange across Vasa Recta; but there is almost no dilution of interstitial fluid in renal medulla. So, the vasa Recta does not create medullary hyperosmolarity but does prevent it from being diluted.



The absorption of water in descending limb of Henle’s loop is ~15%. This absorption depends upon the length of Henle’s loop. In birds where the excretory matter is solid (uric acid), the Henle’s loops are very long.



The absorption of sodium occurs in ascending limb only. (c) In DCT − In this region the absorption of water is 4−5%. But, in the presence of Vasopressin hormone (ADH) the absorption of water from glomerular filtrate increases and may reach upto 10%. It is due to change of permeability of DCT for water.

730

BIOLOGY •

Aldosterone hormone also changes the permeability of DCT, but for sodium, to increase its absorbtion.

•

The absorption of water as well as sodium in DCT is facultative. In the presence of ADH, due to more water absorption, the urine becomes concentrated. (This also allows the urea to pass out of the tubule in medullary region. In the absence of ADH the urea from the medullary tissue may enter into the tubules.)

(d) In collecting tubule and collecting duct− The absorption of water (5−10%) in this part is also ADH dependent. The osmolarity of the fluid ultimately reaches to ~1200 m osm/litre. The term ‘urine’ can be used for the filtrate in collecting tubules. From Bowman’s capsule to DCT the fluid is, however, called glomerular filtrate. H2O (1 + or 3+)

Glomerulus

Check Point 1. Differentiate between: (i) Low threshold and High threshold substances (ii) Facultative and obligatory absorption of water (iii) Cortical nephrons and juxtamedullary nephrons (iv) Glomerular filtrate and urine (v) Diabetes insipidus and Diabetes mellitus (vi) PCT and DCT (vii) The role of descending and ascending limbs of Henle’s loop

Distal convoluted tubule (DCT)

Glomerular Filtrate

Osmolarity at A ~ 300 m Osm/lit.

+

Proximal Convoluted Tubule (PCT)

A

F

B ~ 800 m Osm/lit.

Na (1 + or 3+)

E

CORTEX

D ~ 800 m Osm/lit.

+

Na (4+)

E ~ 150 m Osm/lit.

G OUTER MEDULLA

B H 2O ( 4+ )

C ~ 1200 m Osm/lit.

D

F ~ 300 m Osm/lit. G ~ 600 m Osm/lit. H ~ 1200 m Osm/lit.

H2O (1+ or 3+) NaCl ( 4+ )

Henle's Loop

H

C

INNER MEDULLA H2O (1+ or 3+)

Fig. 19.9 : Absorption of water and sodium in different parts of nephron

(C) Tubular Secretion− Certain secretions, produced from the lining of uriniferous tubule, are added into glomerular filtrate. They include: (1) Creatinine, (2) ammonia, (3) hydrogen ions, (4) potassium ions and (5) uric acid The maximum tubular secretion is added from the lining of PCT and DCT. Composition of Urine−

Connecting Concepts  The amount of urea in blood is 20−30 mg/100 ml and in urine it is 2−3 g/100 ml, that means the concentration of urea in urine is 100 times than that of the blood.

Connecting Concepts  When the urine is allowed to stand, the urea degrades into ammonia and carbon-di-oxide by bacteria and hence, there is smell of ammonia in public urinals.

Amount

−

1−2 litre/day

pH

−

~6 (4.5−7), generally acidic

Specific gravity

−

1.01−1.03

Urea

−

2% (2 g/100 ml of urine)

Salts

−

2% (Mainly NaCl)

(Diuretics increase the volume of urine and amount of electrolyte excretion). Urine of a normal person may contain water soluble vitamins but does not contain proteins and blood elements. The urinary output is increased by the excessive intake of water, proteins, tea, coffee, salts and alcohol etc. (The micturition or urination is primarily a spinal reflex, regulated by higher voluntary centre in brain. During micturition the smooth muscles of urinary bladder, called Detrusor muscle, contract and the sphincter of urethra relaxes to void the urine).

EXCRETORY PRODUCTS AND THEIR ELIMINATION

ACCESSORY EXCRETORY STRUCTURES Besides kidney, the following structures also help in elimination of excretory wastes. 1. 2.

3.

Lungs : The excretory product removed through lungs is carbon-di-oxide. About 18 litre of CO2 is excreted out per hour.

Liver : It releases bile, cholesterol, drugs, vitamins and degraded steroid hormones. The excretory products in bile are bilirubin and biliverdin. The bilirubin is broken into stercobilin and urobilin in intestine, the former imparts colour to faeces and latter to urine. You have read in digestive system that bilirubin is a toxic substance and its accumulation in body produces jaundice. Most of the excretory products of liver are removed through faeces. (Please remember that liver is the largest gland of the body) Skin : Skin is the largest organ of the body and contains sweat glands and sebaceous glands. The sweat of sweat glands removes sodium chloride, a small amount of urea and lactic acid. The sebum of sebaceous glands excretes out substances like sterols, waxes and hydrocarbons etc.

4.

Saliva : It also removes a small amount of nitrogenous wastes.

Dialysis Urea is a toxic chemical. When it is not removed from the body, due to kidney disease, it gets accumulated in blood (Uremia) and can cause kidney failure. The urea can be removed from the blood by dialysis. The dialysis is of 2- types 1.

Peritoneal dialysisIt is less costly but risky as there are chances of infection due to the permanent tube in the abdomen. A fluid (dialysate), containing sodium, chloride, bicarbonate and high percentage of glucose, is introduced into the abdominal cavity through a permanent- attached tube. The peritoneum of abdomen acts as a membrane and the exchange of substances occur with the blood. The fluid, containing urea, is removed periodically.

Dialysis solution

Abdominal cavity

Catheter

Peritoneum

Fig. 19.10 : Peritoneal dialysis

731

732

BIOLOGY 2.

Haemodialysis – It is used to remove urea and creatinine. In such patients the blood is drained out through an artery into a ‘dialyzing unit’ after adding heparin, an anticoagulant. The dialysing unit contains a coiled cellophane tube, surrounded by dialysing fluid. This fluid has same composition as plasma except the nitrogenous wastes. The nitrogenous wastes from the blood pass through cellophane membrane into the dialysing fluid and the blood is cleared of waste substances. The cleared blood, after addition of anti-heparin, is pumped back into the body through a vein. Radial artery

Bubble trap

Blood in

Shunt device with attachments for connection of patient to dialyser

Blood out Dialysate out

Used dialyzing solution

Dialysate in

Fresh dialyzing solution

Constant temperature bath

Fig. 19.11 : Haemodialysis

Kidney transplantation In case of acute renal failure, a kidney from a donor, is permanently grafted into the body of patient. The donor for the kidney should be a close relative otherwise the immune system may reject the transplanted kidney. Before transplantation, the tissue matching (tissue typing) is done and the corticosteroids are injected to supress the immune system. Though, the whole process is complicated but the modern techniques have increased its success rate.

DISORDERS OF EXCRETORY SYSTEM

Check Point 1. Name the followings: (i) The pressure/s that act against ultra-filtration (ii) Structures that produce maximum tubular secretion (iii) Hormone that is directly responsible for water absorption (iv) Disorder in which urine turns black on exposure. (v) Substances which are fully (100%) reabsorbed from glomerular’s filtrate.

(1)

Polyuria – Formation of more than the normal amount of urine.

(2)

Oligouria – Less urine.

(3)

Anuria – No urine formation.

(4)

Phenylketonuria – Phynylketone bodies in urine (a genetical- autosomal recessive disease). Such Persons are mentally retarded.

(5)

Alkaptonuria – Alkapton bodies in urine (also an autosomal recessive disorder). The urine turns black on exposure.

(6)

Glycosuria – Occurrence of glucose in urine.

(7)

Haematuria – Presence of blood or RBC in urine.

(8)

Albuminuria – Passing of protein (Albumin) in urine.

(9)

Cysteinuria – Presence of amino acid (Cystein) in urine. It is an inborn error of metabolism.

EXCRETORY PRODUCTS AND THEIR ELIMINATION (10) Uremia – Accumulation of excess urea and other toxic substances like phenols and organic acids in the blood. Urea is removed by dialysis. (11) Nephritis (Bright’s disease) – The Nephritis is a kidney disorder which develops due to various reasons. It is mainly a bacterial disease in which negative (-ve) charges in glomerular wall are dissipated, and the albumin (protein) can pass into filtrate without an increase in the size of pores in the membrane. Glomerulonephritis – It is the inflammation of glomeruli of kidney. (12) Pyuria – Occurrence of pus-cells in urine. (13) Milky urine – Presence of Phosphates in urine. (14) Diabetes insipidus – It is a condition of more, and diluted urine, due to hyposecretion of ADH or Vasopressin. (15) Diabetes mellitus – It is the presence of glucose in urine due to hyposecretion of insulin. (16) Kidney stones (Renal calculi)– They develop when the amount of uric acid, calcium phosphate or oxalates increases in the urine. These chemicals get precipitated in the urinary passage as kidney stones. (17) Cystitis – It is inflammation of urinary bladder causing frequent urination and burning sensation.

733

734

BIOLOGY

EXERCISE - 1 | NCERT BASED QUESTIONS 1.

2.

3.

4.

5.

6.

7.

8.

The Glomerulus along with Bowman’s capsule is called (1) Column of Bertini (2) Renal capsule (3) Malpighian tubule (4) None of these Mark the correct statement (1) Vasa recta is lacking in cortical nephrons (2) Maximum number of nephrons in kidney are juxtamedullary type (3) DCT of many nephrons open into collecting tubule (4) All of these Which of the following is not the part of renal tubule (1) Henle’s loop (2) Glomerulus (3) Bowmans’s capsule (4) Collecting tubule Which of the following hormone is secreted from kidney (1) ANF (2) Erythropoetin (3) Rennin (4) Aldosterone Filtration slits are formed by (1) Endothelial lining of glomerular capillaries (2) Inner epithelium of Bowman’s capsule (3) Basement membrane (4) The participation of all of these Juxta glomerular apparatus is formed by cellular modification in the (1) Afferent arteriole and DCT (2) Efferent arteriole and PCT (3) Afferent arteriole and PCT (4) Efferent arteriole and DCT Which of the following set contains all groups of ureotelc animals (1) Marine fishes, amphibians and mammals (2) Bony fishes, mammals and terrestrial insects (3) Aquatic insects, amphibians and land snails (4) Bony fishes, aquatic amphibians and terrestrial mammals Match the animals with their corresponding excretory structures (1) (2) (3) (4)

Animal Amphioxus Cockroach Prawn Earthworm

(a) (b) (c) (d) (e) (f)

Excretory structure Pronephros kidney Protonephridia Metanephridia Green glands Malpighian tubules Antennal glands

9.

10.

11.

12.

13.

14.

15.

16.

17.

(1) 1. – b, 2. – e, 3. – d, 4. – c (2) 1. – a, 2. – c, 3. – d, 4. – b (3) 1. – b, 2. – e, 3. – f, 4. – c (4) None of these The projections of renal pelvis are called (1) Hiluses (2) Calyces (3) Medullary pyramids (4) Renal columns Which of the following is not added to the glomerular filtrate by tubular secretion (1) NH3 (2) Uric acid (3) H+ (4) Na+ Glomerular capillaries are (1) Purely arterial (2) Purely venous (3) Arterial as well as venous (4) Portal only Human kidney can concentrate urine nearly by (1) 25 times (2) 99 times (3) 70 times (4) 4 times Which of the following is directly responsible for increasing glomerular blood pressure and hence GFR (1) Aldosterone (2) ANF (3) Angiotensin II (4) Renin Presence of glucose in urine is called (1) Diabetes insipidus (2) Diabetes mellitus (3) Galactosemia (4) None of these Which of the following accessory excretory structure eliminates NaCl, Lactic acid and Urea (1) Kidney (2) Liver (3) Sebaceous gland (4) Sweat gland Urea from the blood can be removed by (1) Uraemia (2) Diuresis (3) Dialysis (4) Micturition In which one of the following organisms its excretory organs are correctly stated? (1) Humans – Kidneys, sebaceous glands and tear glands (2) Earthworm – Pharyngeal, integumentary and septal nephridia (3) Cockroach – Malpighian tubules and enteric caeca (4) Frog – Kidneys, skin and buccal epithelium

EXCRETORY PRODUCTS AND THEIR ELIMINATION

735

EXERCISE - 2 | Window to Competitive Exams 1.

2.

3.

4.

5. 6. 7.

8. 9. 10.

11.

12.

Renin is released from [MP ‘96] (1) Juxtaglomerular apparatus (2) Liver (3) Stomach (4) Spleen In human beings the capsular urine entering the Proximal Convoluted Tubule (PCT) is [PCS ‘96] (1) Isotonic to blood (2) Hypotonic to blood (3) Hypertonic to blood (4) Isotonic to sea water Human urine contains [DPMT ‘96] (1) 95% water, 2.6% urea, 2% salts and some uric acid (2) 99% water and 1% urea (3) 92% water and 8% salts (4) 90% water, 8% uric acid and 2% proteins Ornithine cycle was discovered by [BHU ‘97] (1) Krebs (2) Henseleit (3) Krebs and Henseleit (4) Ornithine Bony fishes are [BHU ‘97] (1) Ureotelic (2) Uricotelic (3) Aminotelic (4) Ammonotelic Flame cells are excretory organs of [BHU ‘97] (1) Prawn (2) Planaria (3) Silver Fish (4) Hydra Glomerulus and Bowman’s capsule constitute [AFMC ‘97] (1) Nephrotome (2) Renal corpuscle (3) Renal capsule (4) Malpighian tubule The ascending loop of Henle is permeable for (1) Ammonia (2) Glucose [MP ‘97] (3) Sodium (4) Water Majority of freshwater bony fishes are [BHU ‘97] (1) aminotelic (2) ammonotelic (3) ureotelic (4) uricotelic Colloidal osmotic pressure in blood plasma is mainly due to [PCS ‘97] (1) albumin (2) globulin (3) fibrinogen (4) sodium chloride The part of the nephron impermeable to water is (1) proximal tubule [PCS ‘97] (2) distal tubule (3) ascending limb of Henle’s loop (4) collectign duct Na+ and Cl– both are removed by [CPMT ‘97] (1) Ascending limb of Henie’s loop (2) Proximal convoluted tubule (3) Both (1) and (2) (4) Descending limb of Henie’s loop

13.

14.

15.

16.

17.

18.

19.

20.

21.

22.

Ornithine cycle removes two waste products from blood in liver [CBSE ‘96, ‘05 ; RPMT ‘98] (1) Urea and carbon dioxide (2) Carbon dioxide and ammonia (3) Ammonia and uric acid (4) Ammonia and urea. In Amoeba, NH3 is excreted through [AFMC ‘98] (1) Food vacuole (2) Plasma membrane (3) Contractile vacuole (4) All the above Malpighian tubules remove excretory products from [CPMT ‘98] (1) Kidney (2) Haemolymph (3) Alimentary canal (4) Liver Which of the following harmful substances are changed into less harmful through ornithine cycle? (1) Urea and uric acid [RPMT ‘98] (2) Urea and ammonia (3) Ammonia and carbon dioxide (4) Ammonia and uric acid Mechanism of uric acid excretion in a nephron is [CPMT ‘92, AIIMS ‘98] (1) Osmosis (2) Diffusion (3) Ultrafiltration (4) Secretion In kidney, nephrostomes are functional in [AFMC ‘99] (1) Tadpole (2) Adult Frog (3) Cockroach (4) Rabbit Bidder’s canal is found in [AFMC ‘99] (1) Testis of frog (2) Kidney of frog (3) Kideny of mammal (4) Ovary of mammal Which of the following is not a nitrogenous waste? [CPMT ‘99] (1) Creatine (2) Guanine (3) Uric acid (4) Carbon dioxide In the renal tubules the permeability of the distal convoluted tubule and collecting duct to water is controlled by [CBSE ‘99] (1) aldosterone (2) vasopressin (3) growth hormone (4) renin Brush border epithelium is characteristic of (1) Neck of nephron [CBSE ‘90; BHU ‘99] (2) Collecting tube (3) Proximal convoluted tubule (4) All the above

736 23.

24.

25.

26.

27.

28.

29.

30.

31.

32.

33.

34.

BIOLOGY The function of renin is [AIIMS ‘99] (1) degradation of angiotensinogen (2) stimulation of corpus luteum (3) to reduce blood pressure (4) vasodilatation The nephrostomes in the kidney are functional in (1) Rabbit (2) Tadpole [AFMC ‘99] (3) Adult frog (4) Young rabbit Normal range of urea in 100ml of human blood is [Kerala 2000] (1) 50-70mg (2) 40-80g (3) 20-30mg (4) 05-15g Funnel-like ciliated pits on the ventral side of the kidney in frog are known as [Haryana 2000] (1) Nephridiopores (2) Nephrostomes (3) Nephrotomes (4) Coelomostomes Metanephric kidneys are found in (1) Reptiles only [PCS ‘96, 2000] (2) Birds only (3) mammals only (4) Reptiles, birds and mammals Functional kidney of tadpole is [BHU ‘01] (1) Pronephros (2) Mesonephros (3) Metanephros (4) Archinephros. Which one is not an excretory organ [Wardha ‘01] (1) Skin (2) Kidneys (3) Intestine (4) Liver Following are four statements. Find out the correct combination. [CET Chd ‘01] A. Glucose has high therehold value B. Urine is concentrated in Henle’s loop C. Haemodialyser removes ureas, uric acid, glucose and proteins D. In glomerulus, urea, uric acid, water, glucose and plasma proteins are filtered out (1) A, C, D (2) B, C, D (3) A, B (4) A, C Uric acid gets deposited in small joints to produce (1) Rheumatoid arthritis [AMU ‘01] (2) Gout (3) Osteoarthritis (4) All of these Haemodialysis is associated with [AMU ‘01] (1) liver (2) spleen (3) kidney (4) stomach In mammalian kidneys, Bowman’s capsules or Malpighian corpuscles occur in [CPMT ‘85, 88, 91, 99, RPMT ‘01] (1) Cortex (2) Medulla (3) Pelvis (4) All of these Which of the following is uricotelic? [PCS ‘01] (1) Pavo (2) Bombyx (3) Phrynosoma (4) All of the above

35.

36.

37.

38.

39.

40.

41.

42.

43.

44.

Diuresis is a condition characterized by [MP ‘01] (1) increase in urine volume (2) increased glucose excretion (3) decrease in urine volume (4) decrease in electrolyte balance Which is finally reabsorbed in distal convoluted tubule (1) Calcium (2) Potassium [TN ‘01] (3) Bicarbonate (4) Water In nephron water absorption is maximum in (1) Proximal convoluted tubule [Haryana ‘01] (2) Ascending limb of Henle (3) Descending limb of Henle (4) Distal convoluted tubule The number of nephrons in a kidney is equal to [KCET ‘02] (1) The numebr of Bowman’s capsules (2) sum of Bowman’s capsules and glomeruli (3) double the number of Bowman’s capsules (4) sum of Bowman’s capsules and Malpighian corpuscles Which is not correct with respect to human kidney? [Orissa ‘02] (1) The peripheral region is called cortex and central medulla (2) Malpighian capsules are present in the cortex region (3) Blood enters glomerulus through efferent arterioles (4) The concave part of kidney is called hilus Choose the correct statement for biosynthesis of urea [Orissa ‘02] (1) uric acid is starting material for biosynthesis of urea (2) urea cycle enzymes are located inside liver (3) urea is synthesized inside lysosomes (4) urea is synthesized in kidney The phenomenon which helps in maintaining a constant internal environment in living organism is [Kerala ‘01, BHU ‘02] (1) homeostasis (2) entropy (3) apoptosis (4) haemolysis Solenocytes and metanephridia are excretory organs of [RPMT ‘02] (1) Annelida and Arthropoda (2) Platyhelminthes and Annelida (3) Coelenterata and Mollusca (4) Aschelminthes and Annelida Trimethylamine oxide is the excretory product in [BHU ‘97; MP ‘02] (1) Marine teleosts (2) Freshwater fishes (3) Molluses (4) Amphibians. The excretory product of excess metabolism of creatine is [BHU ‘02] (1) Creatinine (2) Urea (3) Uric acid (4) Oxalic acid

EXCRETORY PRODUCTS AND THEIR ELIMINATION 45.

46.

47.

48.

49.

50.

51.

52.

53.

54.

55.

56.

Which one is uricotelic ? [AMU ‘89; MAHE ‘01; (1) Frog and toads AIIMS ‘02] (2) Lizards and birds (3) Cattle, Monkey and man (4) Molluses and teleost fishes. Which of the following are uricotelic animals? (1) Rohu and frog [AIIMS ‘02] (2) Camel and frog (3) Lizard and crow (4) Earthworm and eagle Uric acid is formed in human being from [JK ‘02] (1) Proteins (2) glucose (3) purines (4) pyrimidines Loop of Henle takes part in absorption of (1) Potassium (2) Glucose [MP ‘02] (3) Water (4) Urea Urinary bladder is absent in [AMU ‘02] (1) Aves (2) Reptiles (3) Amphibians (4) Mammal Mesonephric kidney is found in [RPMT’02] (1) Aves (2) Reptillia (3) Fishes (4) All of these. Part of nephron involved in active reabsorption of sodium is [JIPMER ‘02] (1) PCT (2) Ascending limb of Henle’s loop (3) Bowman’s capsule (4) DCT Hippuric acid, creatinines and ketones are added to urine through [Punjab ‘02] (1) Reabsorption (2) Glomerular filtration (3) Tubular secretion (4) Both (2) and (3) The part of the nephron that helps in active reabsorption of sodium is [JIPMER ‘02] (1) Bowman’s capsule (2) Distal convoluted tubules (3) Ascending limb of Henle’s loop (4) Proximal convoluted tubules Which one is the excretory structure in the following? [Kerala ‘03] (1) Cnidocyte (2) Solenocyte (3) Pinacocyte (4) Choanocyte Accessory excretory organs of man are (1) only skin [Orissa ‘03] (2) only skin and liver (3) only skin and lungs (4) skin, lungs, liver and intestine Which of the following components of blood does not enter into the nephron? [Orissa ‘03] (1) urea (2) water (3) glucose (4) plasma protein

737 57.

58.

59.

60.

61.

62.

63.

64.

65.

66.

67.

Expulsion of urine become voluntary when it is present in [MHCET ‘03] (1) urethra (2) ureters (3) urinary bladder (4) pelvis of kidneys Excretion of nitrogenous waste product in semisolid form occur in [Kerala ‘03] (1) amniotes (2) desert animals (3) ureotelic animals (4) uricotelic animals Dialysis is done in the condition when person is suffering from: [BHU ‘03] (1) diabetes (2) uraemia (3) polyuria (4) haemolysis Urea is transported by [Wardha ‘03] (1) Leucocytes (2) Blood plasma (3) Haemoglobin (4) RBCs Excretion means [Manipal ‘03] (1) removal of substances which have never been a part of body (2) removal of faecal matter from the body (3) removal of substances not required in the body (4) all of these If Henle’s loop were absent from mammalian nephron which of the following is to be expected [CBSE ‘03] (1) There will be no urine formation (2) There will be hardly any changein the quality and quantity of urine formed (3) The urine will be more concentrated (4) The urine will be more dilute. A terrestrial animal must be able to [CBSE ‘04] (1) conserve water (2) excrete large amoutns of salts in urine (3) excrete large amoutns of water in urine (4) actively pump salts out through the skin Uricotelism is found in [CBSE ‘04] (1) Frogs and toads (2) Mammals and birds (3) Birds, reptiles and insects (4) Fishes and fresh water protozoans Kidney stones are crystals of [Kerala ‘03; MAHE ‘05] (1) silica (2) calcium oxalate (3) potassium chloride (4) sodium bicarbonate Percentage of which increases in blood if liver becomes functionless? [BHU ‘88; Haryana ‘05] (1) Urea (2) Ammonia (3) Uric acid (4) proteins Common excretory product of insects is [JIPMER ‘99; Haryana ‘05] (1) NH3 (2) Urea (3) Uric acid (4) Hippuric acid

738 68.

69.

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71.

72.

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BIOLOGY Which of the following amino acids are present in ornithine cycle? [BHU ‘97, ‘05] (1) Aspartic acid, glycine and glutamic acid (2) Glycine, citrulline and methionine (3) Arginine, citrulline and ornithine (4) Ornithine, Alanine and valine Healthy human does not excrete out in his urine (1) Uric acid [CPMT ‘01; Manipur ‘05] (2) Alanine (3) Creatinine (4) B-complex vitamins The maximum reabsorption of useful substances back into the blood from filtrate in a nephron occurs in [BHU ‘88; KCET ‘05] (1) PCT (2) Loop of Henle (3) DCT (4) Collecting duct Blood leaving liver and moving to heart will have more concentration of [CPMT ‘05] (1) bile (2) urea (3) glycogen (4) amino acid Which one of the following statements is correct with respect to salt water balance inside the body of living organisms ? [AIIMS ‘05] (1) When water is not available camels donot produce urine but store urea in tissues (2) Salmon fish excretes lot of stored salt through gill membrane when in fresh water. (3) Paramecium discharges concentrated salt solution by contractile vacuoles (4) The body fluids of fresh water animals are generally hypotonic to surrounding water. On the basis of Excretion tadpole is [AMU ‘05] (1) ammonotelic (2) ureotelic (3) uricotelic (4) none of these The functional unit of mammalian kidney is [JK ‘05] (1) ureter (2) urinary bladder (3) urethra (4) nephron Which one of the following part is an endocrine glands ? [CPMT ‘05] (1) Brunner’s gland (2) Crypts of liberkuhn (3) juxtaglomerulus (4) pars radiata Osmoregulation in Paramecium is a function of [KCET ‘05] (1) contractile vacuole (2) trichocysts (3) cytopyge (4) cyostome Loop of henle is associatd with [Orissa ‘05] (1) excretory system (2) respiratory system (3) reproductive system (4) digestive system Sea gulls excrete excess of NaCl from [BHU ‘05] (1) liver (2) lungs (3) nasal cavity (4) kidney

79.

80.

81.

82.

83.

84.

85.

Urea is directly produced in mammals from [CPMT ‘05] (1) ammonia released by oxidative deamination (2) oxidative deamination of purines (3) breakdown of ornithine (4) breakdown of arginine Glomerular hydrostatic pressure is present in (1) tubule of kidney [CPMT ‘05] (2) Bowman’s capsule (3) glomerulus of uriniferous tubule (4) malpighian tubule Glomerular filtrate contains [CPMT ‘05] (1) blood without blood cells and proteins (2) plasma without sugar (3) blood with proteins but without cells (4) blood without urea Juxtaglomerular cells of renal cortex synthesizes an enzyme called [Kerala ‘05] (1) ADH (2) oxytoxin (3) renin (4) urochrome Which have minimum concentration of urea in blood? [Haryana ‘05] (1) renal arteries (2) renal vein (3) aortic arteries (4) vena cava Which of the following statements is/are true? [Kerala ‘05] (a) urine is hypertonic in distal convoluted tubule (b) when the urine passes into the collecting tubule, it becomes hypotonic (c) urine is isotonic in proximal convoluted tubule (d) urine becomes more and more hypotonic as it passes through the Henle’s loop (1) (a) and (d) only (2) (a), (b), and (c) only (3) (b) and (c) only (4) (c) only Match the excretory functions of section I with the parts of the excretory system in section II. Choose the correct combination from among the answers given.[Kerala ‘05] Section I (function)

86.

87.

Section II (parts of excretory systems) 1. ultra filtration A. Henle’s loop 2. concentration of urine B. ureter 3. transport of urine C. urinary bladder 4. storage of urine D. malpighian corpuscle E. proximal convoluted tubule (1) 1 - D, 2 - A, 3 - B, 4 - C (2) 1-D, 2 - C, 3 - B, 4 - A (3) 1 - E, 2 - D, 3 - A, 4 - C (4) 1-E, 2 - D, 3 - A, 4 - B The voluntary response to the distension of Urinary bladder is [EAMCET ‘05] (1) Polyurea (2) Micturition (3) Mellitus (4) Menstruation Urea formation takes place in [Orissa ‘05; (1) liver (2) kidney CPMT ‘06] (3) pancreas (4) intestine

EXCRETORY PRODUCTS AND THEIR ELIMINATION 88.

89.

90.

91.

92.

93.

94.

95.

96.

97.

The cells named podocytes occur in [AIIMS ‘98; CPMT 2000’ BHU ‘06] (1) Inner wall of Bowman’s capsule (2) Outer wall of Bowman’s capsule (3) In the wall of glomerulus (4) In the wall of Henle’s loop Earthworms are [CBSE ‘06] (1) uricotelic when plenty of water is available (2) uricotelic under conditons of water scarcity (3) ammonotelic when plenty of water is available (4) ureotelic when plenty of water is available Angiotensinogen is a protein produced and secreted by [CBSE ‘06] (1) endothelial cells (cells lining the blood vessels) (2) liver cells (3) juxtaglomerular (JG) cells (4) macula densa cells Almost all the aquatic animals excrete ammonia as the introgenous waste product. Which of the following statement is not in agreement with this situation? [KCET ‘06] (1) ammonia is a easily soluble in water (2) ammonia is released from the body in a gaseous state (3) ammonia is highly toxic and needs to be eliminated as and when formed (4) ammonia gets converted into a less toxic form called urea. Which of the following is first formed introgenous waste of vertebrate? [GCET ‘06] (1) NH2 (2) urea (3) NH3 (4) NH4 Which of the following is acting as an artificial kidney in haemodialysis? [GCET ‘06] (1) dialysing liquid (2) dialyzer (3) bubble trap (4) blood pump Malpighian tubules are [BHU ‘06] (1) excretory organs of insects (2) excretory organs of frog (3) respiratory organs of insects (4) endocrine glands of insects Which one is an important constituent of renin angiotensinogen-aldosterone system? [AMU’06] (1) JGA cell (2) macular cell (3) erythropoetin (4) plasma cell Podocytes are associated with organisation of (1) filtration slit [HPMT’06] (2) lung alveoli (3) juxtaglomerular apparatus (4) WBC Flame cell are found in [HPMT ‘06] (1) metanephridia (2) green gland (3) book lung (4) protonephridia

739 98.

Osmoconformer are the animal that [HPMT ‘06] (1) do not actively control the osmotic condition of their body fluid (2) actively control the osmotic condition of their body fluid (3) maintain the condition of body fluid within a narrow osmotic range (4) do not change the body fluid according to the osmolarity of ambient medium 99. Land snail are [HPMT ‘06] (1) ureotelic (2) uricotelic (3) ammonotelic (4) both (1) and (3) 100. The GFR of an healthy adult is [JK ‘06] (1) 125 ml/min (2) 80 ml/min (3) 300 ml/min (4) 20 ml/min 101. Renal corpuscles can be divided into [Orissa ‘06] (1) Bowman’s capsule and glomerulus (2) arteriole & glomerulus (3) arteriole & Bowman’s capsule (4) afferent & afferent arteriole 102. Refer the following diagram and identify the parts of a kidney indicated [Kerala’06] a b c

d e

(1) a = cortex, b = nephron, c = pelvis, d = medulla, e = ureter (2) a = c o r t e x , b = m e d u l l a , c = n e p h r o n , d = pelvis, e = ureter (3) a = n e p h r o n , b = c o r t e x , c = m e d u l l a , d = ureter, e= pelvis (4) a = n e p h r o n , b = c o r t e x , c = m e d u l l a , d = pelvis, e = ureter 103. Match the entries in column I with those in column II and choose the correct answer from the followings [Kerala ‘06] Column I a. uremia b. hematuria c. d. e. (1) (2) (3) (4)

Column II 1. excess of protein in urine 2. presence of high ketone bodies in urine ketonuria 3. presence of blood cells in urine glycosuria 4. presence of glucose in urine proteinuria 5. excess of urea in blood a - 5, b -3, c - 2, d - 4, e - 1 a - 4, b - 5, c - 3, d - 2, e - 1 a - 5, b -3, c - 4, d - 2, e - 1 a - 3, b -5, c - 2, d - 1, e - 4

740 104. Consider the following four statements (a - d) about certain desert animals such as kangaroo rat (a) They have dark colour and high rate of reproduction and excrete solid urine (b) They do not drink water, breathe at a slow rate to conserve water and have their body covered with thick hairs (c) They feed on dry seeds and do not require drinking water (d) They excrete very concentrated urine and do not use water to regulate body temperature. Which two of the above statements for such animals are true [CBSE’08] (1) a and b (2) c and d (3) b and c (4) c and a 105. What will happen if the stretch receptors of the urinary bladder wall are totally removed? [CBSE’09] (1) There will be no micturition (2) Urine will not collect in the bladder (3) Micturition will continue (4) Urine will continue to collect normally in the bladder 106. Uric acid is the chief nitrogenous component of the excretory products of: [CBSE’09] (1) Frog (2) Man (3) Earthworm (4) Cockroach 107. The principal nitrogenous excretory compound in humans is synthesised: [CBSE’10] (1) in the liver, but elminated mostly through kidneys (2) in kidneys but eliminated mostly through liver (3) in kidneys as well as eliminated by kidneys (4) in liver and also eliminated by the same through bile 108. Which one of the following statements in regard to the excretion by the human kidneys is correct? [CBSE’10] (1) Ascending limb of Loop of Henle is impermeable to electrolytes (2) Descending limb of Loop of Henle is impermeable to water (3) Distal convoluted tubule is incapable of reabsorbing HCO3– (4) Nearly 99 per cent of the glomerular filtrate is reabsorbed by the renal tubules 109. Urea synthesis takes place primarily in liver because [DPMT’ 10] (1) NH3 and CO2 are present in liver only (2) Hormone ADH is found in liver only (3) Enzyme arginase is present in liver only (4) Kidney is smaller than liver 110. Which one of the following is not a part of a renal pyramid? [CBSE’ 11] (1) Loops of Henle (2) Peritubular capillaries (3) Convoluted tubules (4) Collecting ducts

BIOLOGY 111. Which one of following correctly explains the function of a specific part of a human nephron? [CBSE’ 11] (1) Afferent arteriole : Carries the blood away from the glomerulus towards renal vein (2) Podocytes : Create minute spaces (slit pores) for the filtration of blood into the Bowman’s capsule (3) Henle’s loop : Most reabsorption of the major substances from the glomerular filtrate (4) Distal convoluted tubule: Reabsorption of K+ ions into the surrounding blood capillaries 112. Uricotelic mode of passing out nitrogenous wastes is found in [CBSE’ 11] (1) Insects and Amphibians (2) Reptiles and Birds (3) Birds and Annelids (4) Amphibians and Reptiles 113. Which one of the following statements is correct with respect to kidney’s function and regulation? [CBSE’ 11] (1) During summer when body loses lot of water by evaporation, the release of ADH is suppressed (2) When someone drinks lot of water, ADH release is suppressed (3) Exposure to cold temperature stimulates ADH release (4) An increase in glomerular blood flow stimulates formation of Angiotensin II 114. Ureters act as urinogenital ducts in [CBSE Final’ 11] (1) Frog’s both males and females (2) Frog’s males (3) Human males (4) Human females 115. The maximum amount of electrolytes and water (70 - 80 percent) from the glomerular filtrate is reabsorbed in which part of the nephron? [CBSE’ 12] (1) Proximal convoluted tubule (2) Descending limb of loop of Henle (3) Ascending limb of loop of Henle (4) Distal convoluted tubule 116. Figure shows human urinary system with structures labeled A to D. Select option which correctly identifies them and gives their characteristics and/or functions [AIPMT (NEET)’13]

(1) A- adrenal gland- located at the anterior part of kidney, secrete catecholamines which stimulate glucogen breakdown (2) B- Pelvis- broad funnel shaped space inner to hilum, directly connected to loops of Henle (3) C- Medulla- inner zone of kidney and contain complete nephrons (4) D- Cortex- outer part of kidney and do not contain any part of nephrons

EXCRETORY PRODUCTS AND THEIR ELIMINATION [AMU’13] 117. Functional kidney of mammals is: (1) Archinephros (2) Opisthonephros (3) Pronephros (4) Metanephros 118. In frog’s kidney the urea is eliminated by: [AMU’13] (1) Glomerular filtration (2) Tubular secretion (3) Both (1) and (2) (4) Tubular absorption 119. The peritubular capillaries of the nephron arise from the: [AMU’13] (1) Afferent arteriole (2) Efferent arteriole (3) Renal artery (4) Arcuate artery 120. Which of the following are not ureotelic? [AMU’14] (1) Mammals (2) Terrestrial amphibians (3) Aquatic insects (4) Birds 121. The following is/ are removed during haemodialysis: (1) Urea (2) Glucose [AMU’14] (3) Amino acids (4) All the above 122. Which of the following causes in increase in sodium reabsorption in the distal convoluted tubule?[AIPMT’14] (1) Increase in aldosterone level (2) Increase in antidiuretic hormone level (3) Decrease in aldosterone level (4) Decrease in antidiuretic hormone level 123. Removal of the proximal convoluted tubule from the nephron will result in: [AIPMT’15] (1) More diluted urine (2) More concentrated urine (3) No change in quality and quantity of urine (4) No urine formation 124. Which of the following does not favour the formation of large quantities of dilute urine? [AIPMT’15] (1) Alcohol (2) Caffeine (3) Renin (4) Atrial- natriuretic factor 125. Human urine is usually acidic because: [RE-TEST AIPMT’15] (1) Excreted plasma proteins are acidic (2) Potassium and sodium exchange generates acidity (3) Hydrogen ions are actively secreted into the filtrate (4) The sodium transporter exchanges one hydrogen ion for each sodium ion, in peritubular capillaries 126. Reactions of Ornithine cycle occur in: [UPCPMT’15] (1) Liver to produce urea (2) Kidney to produce urine (3) Liver to produce ammonia (4) Kidney to form urea

741 127. The Juxta glomerular apparatus is a special region formed by close placement and cellular modifications in: [AMU’15] (1) Proximal convoluted tubule and distal convoluted tubule (2) Loop of Henle and collecting duct (3) Afferent arteriole and distal convoluted tubule (4) Afferent arteriole and proximal convoluted tubule 128. Which of the following is most appropriate regarding kidney function regulation? [AMU’15] (1) Renin- Angiotensin mechanism decreases the glomerular filtration rate (GFR) while atrial natriuretic factor increases GFR (2) Renin- Angiotensin mechanism increases GFR while atrial natriuretic factor decreases GFR (3) Renin- Angiotensin mechanism and Atrial Natriuretic factor both increase GFR (4) Renin- Angiotensin mechanism and Atrial Natriuretic factor both decrease GFR 129. Choose the wrong statement regarding urine formation: [KERALA’15] (1) Filtration is non- selective process performed by glomerulus (2) The glomerular capillary blood pressure causes filtration of blood through three layers (3) GFR in a healthy individual is approximately 125 ml/ min (4) The ascending limb of Henle’s loop is permeable to water but allows transport of electrolytes actively or passively* 130. Vasa recta refer to:

[KERALA’15]

(1) Rectum region of the insects (2) Blood capillaries in invertebrates (3) A fine blood capillary network afferent arteriole (4) A fine capillary which runs parallel to Henle’s loop 131. Find the wrongly matched pair: Animal

[KERALA’15]

Excretory organ/ structure

(1) Balanoglossus ---------------------- Proboscis gland (2) Earthworm -------------------------- Nephridia (3) Grasshopper -------------------------- Malpighian tubules (4) Prawn ------------------------------ Flame cells

742

BIOLOGY

EXERCISE - 3 | Test Yourself 1.

2.

3. 4.

5.

6.

7.

8. 9. 10.

11.

12.

Which of the following pressure acts against ultra filtration? (1) Capsular filtrate pressure (2) Glomerular capillary pressure (3) Both of these (4) None of these Amongst the following excretory products which is the most toxic one? (1) Urea (2) Ammonia (3) Uric acid (4) Amino acid Duct of Bellini in kidney lies in (1) Column of Bertini (2) Cortex (3) Pelvis (4) Pyramid Functional unit of human kidney is (1) Seminiferous tubule (2) Bidder’s canal (3) Renal corpuscle (4) None of these The net pressure gradient that causes the fluid to filter out of the glomeruli into the capsule is: (1) 50 mm Hg (2) 75 mm Hg (3) 20 mm Hg (4) 30 mm Hg Counter current multiplier mechanism of kidney consists of : (1) Loop of Henle and Vasa recta (2) Vasa recta and medullary interstitium (3) Loop of Henle and medullary interstitium (4) Convoluted tubule and medullary interstitium Active reabsorption of glucose appears to occur in (1) Distal convoluted tubule (2) Proxomal convoluted tubule (3) Loop of Henle (4) All of above The condition of excess urea in blood is known as (1) Polyuria (2) Haematuria (3) Uraemia (4) Diuresis Which one of the followings is osmoconformer (1) Bony fish (2) Dog fish (3) Hag fish (4) Whale Amount of urine is affected by (1) ADH (2) Aldosterone (3) Length of Henle’s loop (4) All of these Opisthonephros kidney is the modification of (1) Mesonephros kidney (2) Pronephros kidney (3) Metanephros kidney (4) None of these Wolffian duct is the name of (1) Metanephric duct in Rabbit (2) Ureter in human (3) Urinogenital duct in male frog (4) Vas deferens in frog

13.

14.

15. 16.

17.

18.

19.

20.

21. 22. 23.

Which of the following pressure -change leads to an increased G.F.R (1) ↑ Arterial plasma colloid osmotic pressure (2) ↑ Glomerular capillary hydrostatic pressure (3) ↑ Hydrostatic pressure in Bowman’s capsule (4) ↓ Net filtration pressure Activation of renin-angiotensin mechanism results in the followings except (1) Aldosterone secretion (2) Vasoconstriction (3) Decrease in renal sodium excretion (4) Decrease in blood volume Which of the following is not the tubular secretion (1) Ammonia (2) Sodium (3) Uric acid (4) Hydrogen ions In which of the following disorder the urine turns black on exposure(1) Haematuria (2) Uraemia (3) Alkaptonuria (4) Pyuria From origin point of view the kidney is(1) Endodermal (2) Mesodermal (3) Cortex-ectodermal but medulla-mesodermal (4) Cortex-mesodermal but medulla ectodermal In marine fishes the ionocytes of gill membrane (1) Eliminate excess divalent ions (2) Eliminate excess monovalent ions (3) Import extra divalent ions (4) Import extra monovalent ions Which type of nephrons are more numerous in human kidney(1) Juxta-medullary (2) Cortical (3) Nephrons with longer Henle’s loop (4) None of these Antidiuretic hormone (1) Secretion is determined by plasma osmolarity (2) Increases permeability of renal collecting duct cells to water (3) Is secreted by nerve cells with their cell bodies in hypothalamus (4) All the above Most NH3 in kidney is formed in (1) P.C.T. (2) D.C.T. (3) Loop of Henle (4) Collecting tubule Mark the odd one out(1) Afferent arteriole (2) Vasa-recta (3) Henle’s loop (4) Efferent arteriole The purines are catabolized and excreted as(1) Amino acid (2) Uric acid (3) Hippuric acid (4) Ammonia

EXCRETORY PRODUCTS AND THEIR ELIMINATION 24.

25.

26.

27.

28.

29.

30. 31.

32.

33.

34.

35.

36.

March the correct statement regarding human excretory system(1) Right kidney is posterior in position (2) Henle’s loop lies in cortical region of the kidney (3) Renal vein contains more urea than renal artery (4) All of these Type of kidney in group Amniota is (1) Pronephros (2) Opisthonephros (3) Metanephros (4) Meso and metanephros Filtration membrane does not include(1) Endothelial layer (2) Brush-border epithelium (3) Basement membrane (4) Podocyte layer The proximal convoluted tubules : (1) Reabsorb most of the water and salts of the glomerular filtrate (2) Reabsorb half the glucose in the glomerular filtrate (3) Contain juxta glomerular cells which secrete renin (4) Are the main target cells for ADH Counter current mechanism of the kidney consists of : (1) P.C.T and C.T (2) Loop of Henle and Vasa recta (3) C.T. and Vasa recta (4) P.C.T. and loop of Henle What fraction of renal plasma flow is filtered as glomerular filterate? (1) 1/5 (2) 1/2 (3) 1/10 (4) 1/25 Urea is synthesized in the presence of enzyme(1) Renin (2) Urease (3) Uricase (4) Arginase Mark the correct reaction(1) Citrulline + CO2 + NH3 → Ornithine (2) Arginine → Citrulline + Urea (3) Ornithine + NH3 → Arginine (4) Citrulline + NH3 → Arginine If two solutions, differing in osmolarity, are separated by a semipermeable membrane, then (1) Flow of water will take place from hypotonic to hypertonic solution (2) Solute will pass from hypertonic to hypotonic solution (3) Both (1) and (2) correct (4) No change in osmolarity will take place The amount of plasma filtered per hour by both the kidneys is approximately (1) 1.25 lit. (2) 7.5 lit. (3) 10.5 lit. (4) 17.5 lit. What is osmotic concentration of glomerular filtrate present in basal part of lop of Henle (1) 200 mosm/litre (2) 300 mosm /litre (3) 600 mosm /litre (4) 1200 mosm / litre The reabsorption of water in the following part of nephron is obligatory (1) DCT (2) Collecting tubule (3) PCT (4) All of these Mark the correct statement (1) ADH is released from pituitary when osmolarity of the plasma rises (2) ANF is released when blood pressure rises

743

37.

38.

39.

40.

41.

42.

43.

44.

(3) Both of these (4) None of these Mark the incorrect statement (1) Counter-current flow of blood in vasa recta helps to retain the reabsorbed sodium in the renal medulla (2) Glomerular filterate is protein free plasma (3) Vasa recta carry glomerular filterate from distal convoluted tubule to the collecting duct (4) Glomerular filterate in Bowman’s capsule is isotonic to the plasma In Juxta – medullary nephrons (1) Vasa recta is absent (2) Loop of Henle is absent (3) Both (1) and (2) correct (4) Loop of Henle is longer Match the column I with the column II Column I

Column II

A. Earthworm B. Cockroach C. Amphioxus

I. Malpighian tubules II. Green glands III. Solenocytes

D. Prawn

IV. Holonephridia V. Coxal glands

(1) A-IV, B-I, C-III, D-II (2) A-I, B-V, C-IV, D-II (3) A-IV, B-I, C-V, D-II (4) A-III, B-I, C-II, D-V Two main sites of tubular secretion in nephron are (1) PCT and Henle’s loop (2) Henle’s loop and DCT (3) DCT and collecting duct (4) PCT and DCT Atrial natriuretic factor (ANF) is released in response to the increase in blood volume and blood pressure. Which of the followings is not the function of ANF? (1) Stimulates aldosterone secretion (2) Inhibits the release of renin from JGA (3) Stimulates salt loss in urine (4) Inhibits sodium reabsorption from collecting duct For fresh water fishes, which statement regarding osmoregulation is not correct? (1) They do not drink water (2) They lose salts by specialized cells, called ionocytes (3) Water uptake is minimized by body- scales (4) All of these Mark the correct sequence of the components of green glands (1) Labyrinth – coelomosac – nephridial canal – bladder (2) Coelomosac – labyrinth – nephridial canal – bladder (3) Labyrinth – nephridial canal – coelomosac – bladder (4) Coelomosac – nephridial canal – labyrinth – bladder Through the thick segment of ascending limb of Henly’s loop the (1) NaCl can pass by active transport from filtrate to the interstitial fluid (2) NaCl can pass by passive transport into interstitial fluid (3) NaCl cannot pass from the filtrate to interstitial fluid (4) Water can pass freely from filtrate to interstitial fluid

744

BIOLOGY

ANSWER KEY EXERCISE 1 : NCERT BASED QUESTIONS 1. 6. 11. 16.

(4) (1) (1) (3)

2. 7. 12. 17.

(1) (1) (4) (2)

3. 8. 13.

(2) (3) (3)

4. 9. 14.

(2) (2) (4)

5. 10. 15.

(2) (4) (4)

EXERCISE 2 : WINDOW TO COMPETITIVE EXAMS 1. 6. 11. 16. 21. 26. 31. 36. 41. 46. 51. 56. 61. 66. 71. 76. 81. 86. 91. 96. 101. 106. 111. 116. 121. 126. 131.

(1) (2) (3) (3) (2) (2) (2) (3) (1) (3) (1) (4) (3) (2) (2) (1) (1) (2) (4) (1) (1) (4) (2) (1) (1) (1) (4)

2. 7. 12. 17. 22. 27. 32. 37. 42. 47. 52. 57. 62. 67. 72. 77. 82. 87. 92. 97. 102. 107. 112. 117. 122. 127.

(1) (2) (3) (4) (3) (4) (3) (1) (2) (3) (4) (3) (4) (3) (1) (1) (3) (1) (3) (4) (4) (1) (2) (4) (1) (3)

3. 8. 13. 18. 23. 28. 33. 38. 43. 48. 53. 58. 63. 68. 73. 78. 82. 88. 93. 98. 103. 108. 113. 118. 123. 128.

(1) (3) (2) (1) (1) (1) (1) (1) (1) (3) (3) (4) (1) (3) (1) (3) (2) (1) (3) (1) (1) (4) (2) (3) (1) (2)

4. 9. 14. 19. 24. 29. 34. 39. 44. 49. 54. 59. 64. 69. 74. 79. 84. 89. 94. 99. 104. 109. 114. 119. 124. 129.

(3) (2) (2) (2) (2) (4) (4) (3) (1) (1) (2) (2) (3) (2) (4) (1) (4) (3) (1) (2) (2) (3) (2) (2) (3) (4)

5. 10. 15. 20. 25. 30. 35. 40. 45. 50. 55. 60. 65. 70. 75. 80. 85. 90. 95. 100. 105. 110. 115. 120. 125. 130.

(4) (1) (2) (4) (3) (3) (1) (2) (2) (3) (4) (2) (2) (1) (3) (3) (1) (2) (1) (1) (3) (3) (1) (4) (3) (4)

EXERCISE 3 : TEST YOURSELF 1. 2. 3. 4. 5. 6. 8. 9. 10.

(1) Capsular filtrate pressure equals 10mm of Hg. (2) (4) Duct of Bellini is the major collecting duct which opens at papilla of pyramid. (4) Functional unit is nephron or uriniferous tubule. (3) It is 10-20 mm of Hg and is calculated as (GCP COP - CFP). (3) 7. (2) (3) Haematuria is the presence of blood cells in urine. (3) Hag fish can tolerate a wide range of osmolarity. (4) Aldosterone absorbs sodium and hence retains water.

11. 12.

(1) (3)

13. 16.

(2) (3)

17.

(2)

In case of adrenal gland the cortex is mesodermal and medulla is ectodermal ( not in kidney).

18.

(2)

Amount of sodium ions increases in the body as marine fish drink Sea-water.

19.

(2)

Cortical nephrons have shorter Henle’s loop, but are more in number (about 85%).

20.

(4)

21.

22.

(3)

Henle’s loop is a part of Nephron while the rest three are blood vessels.

23. 24. 25. 26. 27.

(2) (1) (3) (2) (1)

29.

(1)

Filtrate is 125 ml per minute out of 650 ml of plasma or 1250 ml of blood.

30.

(4)

Urease does not form urea but decomposes it into ammonia and carbon-di-oxide (by bacteria)

31. 32. 33. 34.

(4) (1) (2) (4)

35.

(3)

The water absorption from DCT and collecting tubule is facultative.

36.

(3)

37. 38. 39.

(3) (4) (1)

ADH absorbs water to reduce osmolarity of the blood. Vasa recta is a network of blood capillaries. This loop is also covered by vasa recta. 40. (4)

41.

(1)

ANF stimulates the loss of sodium in urine while aldosterone absorbs sodium from glomerular filtrate.

42.

(2)

Fresh water fishes gain salt with the help of ionocytes or chloride cells

43.

(2)

44.

(1)

Green gland is also known as antennary gland as it is present in coxa part of each antenna. This limb is impermeable to water

Such kidney is present in cartilaginous fishes. Urinogenital duct is also known as mesonephric duct. 14. (4) 15. (2) In Alkaptonuria, the homogentisic acid passes through urine.

(1)

Henle’s loop lies in the medullary region. Brush-border epithelium is present in PCT. 28. (2)

This filtration is about 125ml per minute.

Chapter

20

Locomotion and Movement Locomotion and Movement While going through the chapter pay special attention to the following – Terms and Definitions – 1. Sarcomere 2. Muscle tetanus 3. Dicondylic skull 4. Sesamoid bone Differences – 1. Movement and locomotion 2. Adductor muscles and abductor muscles 3. A- band and I- band 4. Red muscle fibres and white muscle fibres 5. Procoelous and Heterocoelous centrum 6. Fibrous joint and cartilaginous joint Joints – 1. Ball and socket joint 2. Pivotal joint 4. Atlanto-occipital joint 5. Elbow joint as lever Structures – 1. Muscle fasciculus 2. Cardiac muscle fibres 4. Axis vertebrum Common names – 1. Calf muscles 2. Collar bone 4. Innominate bone 5. Cheek bone 7. Wrist bones 8. Heel bone Numbers – 1. Vertebrae in adults 2. Floating ribs 4. Ankle bones 5. Limb bones Disorders – 1. Rheumatoidal arthritis 2. Sprain

At a Glance  

Muscular tissue



muscle

 

Structure of striated (skeletal) Muscle contraction Osteology

Human endoskeleton

    3.

Immovable joint

 

3.

Shoulder girdle

 

3. 6.

Wish bone Tongue bone

3.

Skull bones

3.

Osteoporosis

Movement is the characteristic of all living beings. Movement can be at cellular level, organ level or there can be movement of the entire body. The movement of entire body is known as locomotion. Amoeba / Entamoeba move with the help of pseudopodia. Paramecium moves by cilia. The movement of sperms occurs by flagellum (enlarged version of cilium) or tail. The movement of macrophages and leucocytes (WBCs) are cellular movements in higher animals. The movement of body parts (called Kinesiology) includes- movement of jaws, eyeball, gut (peristalsis), heart, lungs (breathing), limbs and appendages etc.

 

Axial skeleton

Vertebral column Sternum Ribs

Appendicular skeleton Arms Legs

Joints

Human joints as levers Bones disorders

746

BIOLOGY The locomotion enables the animals to shift the entire body from one place to another. The running, jumping, crawling, flying and swimming etc. are such locomotory movements. The plants do not show locomotion (except few lower plants) but move body parts by phototropism or Geotropism. The important advantages of locomotion are 

For procuring nutrition.



For avoiding unfavourable conditions.



For shelter.



For defending from predators.

 For searching mating - partners. Survey of locomotory structures in different animal groups -

Check Point 1. What are the locomotory structures in the following animals? (i) Entamoeba (ii) Paramecium (iii) Jelly fish (iv) Nereis (v) Euglena (vi) Earthworm (vii) Snail (viii) Planaria (ix) Sepia (x) Sea star



In Porifers the animals are sessile and there are no locomotory structures. Only larvae are free swimming.



In Coelenterates the tentacles are present for movement. The epidermis and gastrodermis also have epithelio- and endothelio muscular cells for locomotory movements, like somersaulting and looping etc.



In Annelids the longitudinal and circular muscles are differentiated and the animal moves either with the help of Parapodia (Neries ( ) or Setae (earthworm). The locomotory structure in leech is posterior sucker. The coelomic fluid in these animals acts as a hydrostatic skeleton.



In Arthropods, the jointed appendages, and in molluscs, the foot is used for locomotion. The chitin in arthropods forms exoskeleton and provides support to the muscles.



In Echinoderms the water vascular system ((Ambulacral system) is utilized by tube feet for locomotion.



In Vertebrates the locomotion is with the help of skeletal muscles associated with the endoskeleton of limbs.

STRUCTURE OF BICEP (SKELETAL) MUSCLE 

The outermost – connective tissue covering of muscle is called Epimysium. The Epimysium surrounds many bundles of muscle fibres.



Each bundle of muscle fibre, called fasciculus, is surrounded by another connective tissue covering called Perimysium.



Inside fasciculus there are several muscles fibres, each surrounded by connective tissue covering called Endomysiun.

Structure of Muscle fibre 

In ordinary light there appear alternate dark and light transverse bands in the muscle fibrils. The width of dark band is ~1.5µ and the width of light band is ~ 0.8µ .



In polarized light the dark band is Anisotropic, so called A-band, whereas the light band is Isotropic, so called I-band.



The dark band (A-band) in the centre contains outer H-band and inner M-band.



The light band (I-band) in the centre contains a Zig-Zag line/band, called Z-band or Krause membrane.



The distance between two adjacent Z-bands/ Krause membranes is called Sarcomere.



The Sarcomere is the functional unit of muscular tissue. It includes 1 A-band and 2- halves of I-band.

A-band 

It contains thick as well as thin protein filaments.



The diameter of thick filaments is more than the diameter of thin filaments.

LOCOMOTION AND MOVEMENT

747



The number of thick filaments is lesser than the number of thin filaments.



The H-band contains thick filaments only.



The M-band, present in the centre of H-band, also contains thick filaments but is prominent due to their thickening.

I-band 

It contains thin filaments only.



The diameter of these filaments is lesser while the number is more than the thick filaments.

striation myofibril

nucleus

myofibril I band Thick Filament

SARCOMERE

Z-band or Krause membrane

Thin Filaments

M-Band

I-Band

H-Band A-Band

I-Band

Fig. 20.1 : Detailed structure of a muscle fibre

Thick filaments 

They contain Myosin protein and are also called as Myosin filaments. The myosin is a contractile protein.



Each molecule of myosin protein contains 6-polypeptide chains, 2-heavy chains and 4-light chains. Both heavy chains are spirally twisted to form double helical structure. One end of each chain is folded to form a globular (tertiary) structure called Myosin head. Thus, there are 2-heads for each molecule. The rest of the double helical structure is called Tail. The 4-light chains are also the part of head, 2-in each head. Albert Scent Gyorgyi, with the help of trypsin digested the myosin molecule into 2 parts - the anterior part with head, called HMM (Heavy Meromyosin) and posterior part LMM (light Meromyosin). The heads of myosin act as hooks forming the cross-bridges with the active site of actin. Each head also acts as ATPase in the presence of Mg2+. Thick filaments are present in A-band only.



748

BIOLOGY Myosin molecules

Tropomyosin protein spiral Actin molecules Cross-bridge binding site

Myosin head

(1) Thick Filament

2-light chains

Head

Tail Troponin molecule Thin filament

2 Heavy chains Detailed structure

2-light chains

Head

(2) 1-Myosin molecule (A) G-actin

By Trypsin digestion

Light meromyosin (LMM)

Heavy Meromyosin (HMM) Actin binding site

(B) F-actin ATP-binding site

(A) and (B) - Actin molecule

Cross-arm

Fig. 20.2 : Actin and Myosin filaments

Thin filaments 

They contain mainly Actin protein, so called actin filaments. They also contain Troponin and Tropomyosin proteins



The ratio between actin (~ 20%) and myosin (~ 55%) in muscles is 1:3.

 Thin filaments are present in both A and I-bands Actin is a fibrous protein and is of two types 1. G-Actin (Globular-Actin) – It is a monomer. 2. F-Actin (Fibrous-Actin) – It is a polymer and participates in contraction process Troponin – 

It is a complex globular protein.



It covers active sites on tropomyosin.

It has high affinity for calcium. When calcium (Ca2+ ) binds with the troponin the active sites of actin filament are exposed. Tropomyosin – 



Just like actin, it is also a fibrous protein ( rod shaped)



It forms double helical structure. The two helical strands are coiled around F-actin.

MUSCLE CONTRACTION Huxley and Huxley (1954) described the Sliding filament theory of muscle contraction. According to this theory the important steps of muscle contraction are as follows : 

In Skeletal muscles the nerve impulse reaches neuro-motor junction (Motor end plate) and spreads through T-Tubule system. Two-such systems are present in the muscle fibres of higher vertebrates and one- in the fibres of lower vertebrates eg. Frog. T-Tubule system is present on either side of sarcomere in first case and in the centre of sarcomere in the second case.



At terminal point (in Neuromotor Junction) the acetylcholine ( a common neurotransmitter) is released.



Acetylcholine stimulates SR ( Sacoplasmic reticlulum = endoplasmic reticulum ) for the release of calcium ions.

LOCOMOTION AND MOVEMENT

749



Calcium binds to the specific sites of troponin.



The conformation of troponin, which has high affinity for Ca++, changes and the active sites on actin are exposed.



The heads of myosin filaments get attached to the active site to form cross-bridges.



Due to the formation of such cross-bridges the thin filaments slide between thick filaments, and the size of I-band reduces.



Sliding continues and H-band disappears. The I-band also disappears later.



All sarcomeres show similar changes and the whole muscle undergoes contraction. Half I-band Z

One A-band M

myosin filament Z Cross bridge

actin filament

H

HMM Myosin filaments

Z-band (A) Cross-bridge formation

Check Point

Z-band

(B) Sliding of Actin filament

Fig. 20.3 : Diagrammatic representation of Muscle contraction

Energy Metabolism 

During aerobic conditions muscle glycogen changes into glucose and then into pyruvic acid to enter into Kreb’s cycle, to release energy in the form of ATPs.



The ATPs so produced cause muscle contraction and themselves change into ADPs.



Creatine phosphate (C.P) changes ADPs again into ATPs ADP + Creatine phosphate → ATP + Creatine



During anaerobic respiration muscle glycogen, through glucose and pyruvic acid, changes into lactic acid which accumulates in muscles and produces muscle – fatigue.



The so formed lactic acid, through blood, reaches liver. One fifth of this lactic acid is converted into CO2 and H2O and four fifth changes into glucose which ultimately reaches muscles as muscle glycogen. This cycle, describing the fate of lactic acid in liver, is known as ‘Cori & Cori cycle’.

MUSCLE

LIVER Liver glycogen

Muscle glycogen

glucose

Blood

pyruvate 4/5 O2 +nt

pyruvate O-nt 2 Lactate (L. acid)

glucose

1/5

CO+HO 2 2

Lactate (L. acid) Blood

Fig. 20.4 : CORI and CORI Cycle (Lactic acid cycle)

The single contraction in a muscle fibres is called muscle twitch. The sustained contraction of the muscle is called muscle tetanus. Most of our day to day activities are due to muscle tetanus.

1. Fill in the blanks, each with a suitable word/statement. (i) The structural and functional unit of muscles are ........................... and ........................... (ii) ......................... are the proteins of thin filaments of muscle fibril. (iii) Krause membrane is present in the centre of ................... band (iv) ........................... band contains both thick and thin filaments (v) The head of ........................... protein also acts as ATPase. (vi) .......................... of thin filaments has high affinity for Ca++. (vii) The accumulation of .................... causes fatigue in muscles. (viii) Cori & Cori cycle is related to the fate of .......................... (ix) ................. (neuro transmmitter) is released at neuromotor junction. (x) The sustained contraction in muscles is called .......................

750

BIOLOGY

Muscular disorders 1.     2.   

   3.     4.   

5.    6.  

Muscular dystrophy – The most common muscular dystrophy is Duchenne’s muscular dystrophy. It is a genetic disorder. Its gene, ‘Dystrophin’, is present on X- chromosome and is known to be the longest gene (2,400 kbp) of the human genome. It causes degeneration of skeletal muscles. The common symptoms however include, weakness of muscles, loss of mobility and lack of co-ordination. There is no specific cure for this disorder. Myasthenia gravis – It is a chronic autoimmune disease. It causes breakdown of neuromuscular junction due to which the brain loses control over muscles. The important changes include- increase in synaptic clefts, decrease in amount of acetylcholine and the number of receptors at motor end plate. Moreover, the impulses are not transmitted effectively from nerve fibre to muscle fibres. It is characterized by weakening of muscles, fatigue and later paralysis. The symptoms may include drooping eyelids, difficulty in swallowing, muscle fatigue, difficult breathing and inability to control facial expressions. Myasthenia gravis may be controlled by medication or surgical methods. Tetany – It is due to low concentration of calcium in blood (hypocalcemia), caused by hyposecretion of PTH. There is spasmic (sudden) contraction of muscles. The muscle -tetany is different from muscle- tetanus which is sustained voluntary contraction. The muscle tetanus is again different from bacterial tetanus (lock- jaw disease), caused by infection of Clostridium tetani. Cramps – They are painful involuntary contractions of skeletal muscles. The cramps occur due to salt imbalance, fatigue, stress or imperfect posture. They usually occur in calf muscles, thigh muscles or hands, latter called writer’s cramps. (The spasm is sustained involuntary contraction of muscles) Cerebral palsy – It is one of the most common congenital disorder. It affects muscular system due to which the body posture, balance and the motor functions are affected. The brain damage, before or during child birth, causes loss of muscle- tone. This in turn causes problems in carrying out routine physical task in children. Fatigue – It is tiredness due to prolonged muscular activity. It occurs due to dehydration (loss of water and salts) or accumulation of metabolic wastes (e.g. Lactic acid).

HUMAN ENDOSKELETON  

T Total number of bones in adult human (endoskeleton) = 206. The endoskeleton consist of two major parts. 1. Axial skeleton ( forming body axis ) = 80 bones 2. Appendicular skeleton = 126 bones

LOCOMOTION AND MOVEMENT

751 28 + 1

30

30

1

1

26

1

30

30

Fig. 20.5 : Diagrammatic representation number of bones in human skeleton

Axial Skeleton It includes skull, hyoid apparatus, vertebral column, sternum and ribs (Total 80 bones). Skull = 28 bones hyoid = 01 bone Vertebral column = 26 bones 80 bones Sternum = 01 bone Ribs = 24 bones Skull – 28 bones Cranium = 08 bones Face = 14 bones Ear = 06 bones ( 3 + 3 ) Cranium includes frontal (1) , parietal (2), temporal (2), Occipital (1), Ethmoid (1) and sphenoid (1). The occipital bone of cranium contains Foramen magnum through which the brain continues as spinal cord. There are two occipital condyles, one or either side of foramen magnum. Such a skull is known as Dicondylic skull. Besides mammals, the dicondylic skull is also present in Amphibians (frog). The skull of fishes, reptiles and birds are Monocondylic with single occipital condyle on ventral side of foramen magnum.

Sphenoid bone

Parietal bone

CO SU RON TU AL RE

Frontal bone

Temporal bone

Nasal bone Ethmoid bone Lacrimal bone Zygomatic bone Maxilla

LAMBDOIDAL SUTURE

Occipital bone Mastoid process

Mandible Fig. 20.7 : Bones of skull

Foramen magnum Condyles Fig. 20.6 : Occipital bone

752

BIOLOGY Face – Maxilla (upper jaw)

=

02 bones

Mandible (lower jaw)

=

01 bone - (only movable bone of the skull.) . .)

Zygomatic Arch (bone)

=

02 bones

Zygomatic Arch, also known as cheek bone, in Rabbit is formed by a process of squamosal, complete jugal and a process of maxilla. The presence of this arch is the characteristic of all mammals. The other bones of face include Nasal (2), Lacrimal (2), Palatine (2) and Turbinals (2) (inferior conchae) and Vomer (1). The bones in each ear are malleus, incus and stapes. Hyoid bone – 

It is also known as Tongue bone.



It is ‘U’ shaped and does not articulate with any other bone.



It is present in the throat part, and if included in the skull makes the total number of the skull bones to be 28 + 1 = 29.

Vertebral Column 

Back bone has 26 vertebrae in adults (33 vertebrae in children).



A typical vertebrum has Amphiplatyon or acoelous centrum (see connecting concept), two transverse processes, a neural arch with neural canal for spinal cord, and a neural spine in the dorsal side.



The articulating surfaces of the vertebrae are called pre-zygapophysis and post- zygapophysis in the anterior and posterior side respectively. (In between adjacent vertebrae there are tough intervertebral discs of fibrous cartilage. These discs provide flexibility to the vertebral column. The central part of each disc is soft, and is called Nucleus pulposus).

Transverse process

Neural spine

Neural canal Articulating surface Centrum

Fig. 20.8 : Typical vertebrum

LOCOMOTION AND MOVEMENT

753

Connecting Concepts

Types of centra – Centrum is the solid part in the vertebral column and develops from embryonic notochord. There are following main types of centra in different vertebrate groups. 1. Procoelous Centrum – The Centrum having concavity in the anterior side and generally a convexity in the posterior side. eg. Vertebrae of amphibians and reptiles 2. Amphicoelous Centrum – Both surfaces (anterior and posterior) have concavities. eg. Vertebrae of fishes and 8th vertebrum of frog. 3. Heterocoelous Centrum (Saddle shaped) - Each surface (anterior or posterior) has a pair of concave and convex surfaces. eg. Vertebrae of birds. 4. Acoelous – No concavity present on either side of centrums. eg. 9th vertebrum of frog. It has double convexity in the posterior side. In the mammalian verterbrae, both the surfaces of centrum are flat (without concavity or convexity). Such centrum in mammals is better called as Amphiplatyon. Ant. Ant. Ant. Dorsal Dorsal

Post. Procoelous

Post.

Ant.

Post.

ventral

ventral

Post.

Heterocoelous Amphicoelous (Ant = Anterior ; Post. = Posterior)

Amphiplatyon

Fig. 20.9 : Different types of Centra

7 Cervical vertebrae

Vertebral Column in human – S. No. 1. 2. 3. 4. 5.

Region of back bone and name of vertebrae Neck region – Cervical Vertebrae Chest region - Thoracic Vertebrae Abdominal region - Lumber Vertebrae Hip region - Sacral Vertebrae Tail region -Caudal Vertebrae Total vertebrae

No. of vert. in child 7 12 5 5 4 33

No. of vert. in adult 7 12 5 1 (Sacrum) 1 (Coccyx) 26

12 Thoracic vertebrae

Vertebral Formula – Child – C7 T12 1.

L5

S5 Cd4

Adult – C7 T12

L5

S(1) Cd(1)

Cervical (Neck) Vertebrae = 7 Presence of 7 – Cervical Vertebrae is the characteristic of mammals. The exceptions are Sea cows– marine herbivores mammals (group Manatee). They contain 6-9 vertebrae in neck region

5 Lumbar vertebrae

The peculiar feature of cervical vertebrum is the presence of Foramen transvarsarium (vertebro- arterial canal) in the transverse processes, for cervical arteries. 1st – Atlas – 

Transverse processes reduced



Neural spine reduced.



Centrum reduced.



Prezygapophysis absent.



Sacrum

Coccyx Two facets, forming Atlanto - Occipital joint, are present for two occipital condyles of Fig. 20.10 : The vertebral column skull. lateral view

754

BIOLOGY Facet for articulation with odontoid process of axis Facet for articulation with occipital condyle

Foramen for vertebral artery Fig. 20.11 : Atlas

2nd – Axis 

Odontoid process or ‘Dens’ is present in the anterior side of Centrum - forming pivotal joint for rotating skull.



Both pairs of zygapophysis present. ( 3rd to 7th ) - Typical Cervical – Have all features of typical vertebrum. Odontoid process Facet for atles

Foramen for vertebral artery

Transverse process Body

Fig. 20.12 : Axis

2.

8th to 19th - Thoracic Vertebrae - 12 Two pairs of facets for ribs- attachment present.



Anterior thoracic vertebra have longer neural spine.



Posterior thoracic vertebra have shorter neural spine. Neural spine articular process Transverse process

Vertebral foramen

Facets for articulation with ribs

centrum

Fig. 20.13 : Thoracic

3.   

20th-24th - Lumber Vertebrae - 5 They are the Biggest vertebrae of the backbone. Ribs – facets absent. Extra articulating surfaces, ie. Metapophysis (ant.) and anapophysis (post.) present for better movement in this region.

LOCOMOTION AND MOVEMENT

755

Neural spine Transverse process Vertebral foramen

articular process

Centrum

Fig. 20.14 : Lumbar

4.   

25th - Sacral Vertebrae - 5 fused into 1 (Sacrum) Adults have single sacrum. Four pairs of foramina (openings) present. A large facet is present on either side of vertebrum for ilium bone of hip girdle. Articular Articulating process surface for for L5 intervertebral disc

S1

facet for Ilium

S2 Foramena for passage of nerves

S3 S4 S5 Coccyx

C1 C2 C3 C4

Fig. 20.15 : Sacrum (S1 – S5) and Coecyx (C1 – C4)

5.

26th - Caudal Vertebrae - 4 fused into 1 (Coccyx)



Adults have single but fused caudal vertebrum, the Coccyx.



Due to absence of tail it is vestigial in human.

 Transverse processes are rudimentary or absent. STERNUM – 1 

Commonly called breast bone .

Single and consists of three parts, i.e. manubrium, body of sternum and xiphoid process. The xiphoid process provides attachment to diaphragm. RIBS - 12 pairs 



Dorsally they are attached to vertebral column and ventrally to the sternum. 1. True ribs – 7 pairs (1st to 7th pair) – directly attached to sternum through intercostal cartilages. 2.

False ribs – 3 pairs ( 8th to 10th pair) – indirectly attached to sternum through intercostal cartilage of 7th rib. Hence, also called as ‘vertebrochondral ribs’.

3.

Floating ribs – 2 pairs ( 11th & 12th pair ) – not attached to sternum

756

BIOLOGY Clavicle

Manubrium of sternum Ribs Costal cartilages Body of sternum Xiphoid process of sternum

Rib 12 Rib 11 Fig. 20.16 : Sternum and Ribs

All ribs in mammals are double headed (Bicephalic). Both heads, Capitulum and Tuberculum are present on one side of the rib and are attached to vertebrae of thoracic region. In birds also, the ribs are double headed but they have Uncinate process also. In reptiles they are single headed. In frog the ribs are absent.

Appendicular Skeleton It includes the bones of pectoral and pelvic girdles, and the bones of arms and legs (Total 126 bones). Pectoral girdle = 04 bones ( 2 + 2 ) Arms = 60 bones ( 30 + 30 ) Pelvic girdle = 02 bones ( 1 + 1 ) Legs = 60 bones ( 30 + 30 ) Pectoral girdle (Shoulder girdle) – 4 bones • Each half of pectoral girdle has two bones, ie. clavicle (collar bone) and scapula. • A spine, acromian process, is attached to scapula for articulation with clavicle bone. • Scapula, called universal bone of pectoral girdle, contains glenoid cavity for the articulation of humerus. • Coracoid process is also formed from scapula bone. Spine Coracoid process Acromion process

Glenoid cavity

Fig. 20.17 : Pectoral girdle (Half)

LOCOMOTION AND MOVEMENT

(i)

ARMS – 30 bones in each arm Upper arm – 1 bone ( humerus ) Lower arm – 2 bones ( Radius – ulna ) Wrist – 8 bones (carpals) - 4 in each row Palm –5 bones (metacarpals) Fingers – 14 bones (phalanges) Humerus -

Connecting Concepts

•

 In birds the clavicles and interclavicle of pectoral girdle are fused to form a Head of humerus articulates in the glenoid cavity of pectoral girdle. fork – shaped bone, called Furcula or A deltoid ridge is present in the middle of the humerus for attachment of bicep Wish bone or Bone of merry thoughts.

•

Bicipetal groove present.

•

(ii)

757

muscles.

• Distal end of humerus articulates with the radius-ulna to form elbow. Radius - Ulna •

Radius is towards body axis and is shorter than ulna.

•

Ulna forms Olecranon process to form elbow.

•

Radius and ulna together form Sigmoid notch at proximal end Scaphoid Capitate Trapezium Trapezoid

Lunate Triquetral Pisiform Hamate

1st metacarpal

5th metacarpal

Proximal phalanx Distal phalanx

Proximal phalanges I

Middle phalanges Distal phalanges V

IV

II III

Fig. 20.18 : Bones of Hand

(iii) Carpals – 2- rows. Proximal row contains Scaphoid, Lunate, Triqutral and Pisiform. The distal row contains Trapezium, Trapezoid, Capitate and Hamate. Pelvic girdle (Hip girdle) •

•

Half of pelvic girdle is called innominate bone (Osinnominatum) or coxal bone.

•

Innominate bone is formed by the fusion of three bones, i.e. Ilium, Ischium and Pubis.

•

Obturator foramen is formed by the participation of Ischium and Pubis.

•

Acetabulum cavity is formed by the participation of all three bones. Head of femur articulates in Acetabulum cavity.

758

BIOLOGY

Check Point

Iliac crest

1. Match the structures of Column A with the name of the bones in Column B : Column A Column B 1. Acromian (a) Ulna process 2. Deltoid ridge (b) Femur 3. Xiphoid (c) Coracoid process 4. Obturator (d) Scapula foramen 5. Olecranon (e) Ribs process (f) Sternum (g) Pelvic girdle (h) Humerus

Ilium

Acetabulum with lines indicating joints

Spine of ischium Ischial tuberosity Obturator foramen

Symphysis pubis Ischium

Pubis Joint between ischium & pubis

Fig. 20.19 : Pelvic girdle (Half)

Two innominate bones are attached at pubis through fibrous cartilage (pubic symphysis). LEGS - 30 bones in each leg Thigh – 1 bone ( Femur ) Knee Cap – 1 bone ( Patella ) Shank - 2 bones ( Tibia – fibula ) Ankle – 7 bones ( Tarsals ) Sole - 5 bones ( Metatarsals ) Toes – 14 bones ( Phalanges ) •

Talus Navicular 3 cuneiform 5 metatarsal 1 2

14 phalanges

3 4 5

Calcaneus

Cuboid Fig. 20.20 : Bones of Foot

(i)

•

Connecting Concepts

It is strongest, heaviest and the longest bone of human skeleton.

•

 The bones formed from the ossification of ligaments or tendons are called Sesamoid bones.

(ii) Connecting Concepts

Femur The head of femur articulates in the acetabulum cavity of pelvic girdle. Two prominent processes, called trochanters, are present in the head region for muscle attachment. Patella –

•

It is formed by the ossification of tendons.

 In frog tibia and fibula are fused to (iii) Tibia – Fibula form Tibio- fibula which is the longest • Tibia is stronger whereas fibula is a weak bone. bone of the frog’s body.

(iv) Tarsals – •

In 3 – rows. 2 ( Talus and calcaneum or calcaneus) + 2 ( Navicular and cuboid) + 3 (cuneiform).

•

Calcaneum is the longest tarsal and forms the heel of the foot.

LOCOMOTION AND MOVEMENT

759

JOINTS 3 types- 1. Fibrous (fixed) joints 2. Cartilaginous (imperfect) joints 3. Synovial (perfect) joints Fibrous connective tissue

Cranial bone

Intervertebral disc (Fibrous cartilage)

spongy bone

Centrum (vertebrum)

(A)

(B)

Periosteum compact bone fibrous capsule

synovial cavity containing synovial fluid hyaline cartilage

synovial membrane (C)

Fig. 20.21 : (A) Fibrous joint, (B) Cartilaginous Joint, (C) Synovial Joint

1.

Fibrous Joints (Fixed or immovable joints) – SYNARTHROSES • Fibrous connective tissue present between two articulating bones. • Such joints are immovable eg. Joints of Cranium – bones, Joints between Teeth and Jaw bones. 2. Cartilaginous Joint ( Imperfect joint ) – AMPHIARTHROSES • Fibrous Cartilage present between two articulating bones. • Such joints permit limited movements. eg. Joints between mammalian vertebrae (through Intervertebral disc), and two innominate bones ((pubic symphysis) 3. Synovial Joint ( Perfect joints ) – DIARTHROSES • Synovial fluid is present between two articulating bones. • Articulating bones at the joint have hyaline or articular cartilages. • The synovial fluid, enclosed in synovial membrane, is present in synovial cavity. Types of synovial joints – (i) Ball and socket joint – eg. Shoulder joint, Hip joint and Joint between Incus and Stapes of ear ossicles. In shoulder joint, the head of the humerus ( ball ) articulates in the glenoid cavity ( socket ) of pectoral girdle. In hip joint the head of femur ( ball ) articulates in the acetabulum cavity (socket) of pelvic girdle. (ii) Hinge joint - eg. Elbow joint, Knee joint, Ankle joint, Inter phalangeal joint and joint between Malleus and Incus of ear ossicles. Elbow joint is formed between humerus and sigmoid notch of radius – ulna. Knee joint is formed between femur and tibia – fibula. Ankle joint is present between tibia fibula and talus ( a tarsal ) (iii) Saddle joint (Condyloid joint) - eg. Wrist joint, tempo-mandibular joint, Thumb joint and joint between metacarpals and phalanges. This joint is also ball and socket type but both ball and the socket are poorly developed and can not have free movement. (iv) Pivotal joint - eg. Skull joint (not cranial joint) and Joint between Radius and Ulna. Skull joint is present between odontoid process of axis vertebrum and Atlas/skull. In case of radius ulna, one end of radius (in the fore arm) rotates around ulna to form such joint. (v) Gliding/Sliding joint - eg. Inter-carpal joint, Inter-tarsal joint, Sterno-clavicular joint and joint between pre and post zygapopysis of adjacent vertebrae.

Human Joints as Levers – 3 types 1.

Class-I lever - eg. Atlanto -occipital joint (up and down movement of the head) In this lever the skull acts as a weight/resistance and joint acts as a fulcrum. The force of effort is made by neck muscles at the other end.

Check Point 1. Write the type of joints against the name of the bones/bone-parts. (i) Metacarpal and phalanges ..................................................... (ii) Humerus and radius ulna ..................................................... (iii) Femur and acetabulum cavity .................................................... (iv) Two pubis bones of pelvic girdle .................................................... (v) Tibio fibula and Tarsals .....................................................

760

BIOLOGY resistance

effort

fulcrum I

resistance

fulcrum

II

effort

resistance

effort

effort

fulcrum

III

effort gastrocnamius muscle biceps muscle

resistance resistance neck muscles

fulcrum resistance

fulcrum

fulcrum effort

Fig. 20.22 : Types of levers : Class I, II and III in human skeleton

2. 3.

Class-II lever - eg. Toes- joint (while resting on toes). In such joint the weight of the body/resistance is in the centre. Class-III lever - eg. Elbow joint In such joint the effort for bending the fore arm with the help of muscles comes in the centre.

BONES DISORDERS1.

Check Point 1. Answer the followings: (i) Which type of arthritis is an autoimmune disorder? (ii) In which disorder the bones become porous and fragile? (iii) What is the difference between simple and compound fracture? (iv) What type of joint is present in cranial bones? (v) Which type of lever the elbow joint represent? (vi) What is the difference between fibrous joint and fibrous cartilage joint? (vii) Which process of axisvertebrum forms the pivotal joint? (viii) What is the other name for cartilaginous joints? (ix) Which tarsal forms the heel of the foot? (x) In which type of arthritis the sodium urate crystals get deposited?

Osteoporosis – • It is due to hormonal imbalance mainly of PTH or Sex hormones, or due to prolonged treatment of steroids. • It is ageing disorder and makes the bones porous and fragile. 2. Arthritis (Joint disorders) – (i) Gout • Salts of uric acid (sodium urate) are deposited in the joints. • The movement becomes stiff and painful. • This type of arthritis is generally hereditary (a sex influenced – autosomal trait). (ii) Osteoarthritis • It is an old age disorder. • The hyaline cartilage gets eroded. (iii) Rheumatoidal arthritis. • It is an autoimmune disorder characterized by the presence of Rheumatoidal factor (Immunoglobulin- Ig M) • Synovial membrane gets inflammated and the amount of synovial fluid increases. This exerts pressure and pain. • The thick synovial membrane secretes abnormal granules, Pannus, which cause erosion of cartilage. • The fibrous tissue gets ossified and makes the joints immovable. 3. Fracture : It is breaking of bone (Partial or complete) and can be (i) Simple or closed type When the broken ends of the bone do not protrude through the skin. (ii) Compound or open type In such a case the broken ends pierce through the skin. (iii) Transverse - The fracture is at right angle to the length of the bone. (iv) Spiral - The fracture is spiral, or bones are twisted. (v) Greenstick - It is a partial fracture in which one side of the bone bends and other side is broken. This occurs in children only.

LOCOMOTION AND MOVEMENT

761

EXERCISE - 1 | NCERT BASED QUESTIONS 1.

2.

3.

4.

5.

The macrophages in human body exhibit (1) Ciliary movement (2) Amoeboid movement (3) No movement (4) Movement with the blood flow only Mark the incorrect statement in the followings (1) All movements lead to locomotion (2) Ciliary movement help in passage of ova through female reproductive tract (3) Microfilaments are involved in amoeboid movement (4) In Paramecium the cilia help in movement of food through cytopharynx and in locomotion as well Read the following 4-statements (A – D) and accordingly mark the option that has both correct statements A. Cardiac fibres are branched with one or more nuclei B. Smooth muscles are unbranched and cylindrical C. Striated muscles can be branched or unbranched D. Involuntary muscles are non-striated 1. A and D 2. B and C 3. C and D 4. A and C Which of the following is not the feature of red muscle fibres (1) They have plenty of mitochondria (2) They have high content of Myoglobin (3) They have high amount of Sarcoplasmic reticulum (4) They are called aerobic muscles Match the bones of column A with their corresponding number in column B Column A A. True ribs B. Cervical vertebrae C. Cranium bones D Vertebrochondral ribs

6.

7.

8.

a. b. c. d.

Column B 14 12 8 6

(1) Ab, Be, Ca, Dd (2) Aa, Be, Cc, Dd (3) Ab, Bc, Cd, Dc (4) Aa, Bc, Cb, Dd What is not true about human skull (1) It is dicondylic (2) It includes 6 ear ossicles (3) It includes 14 facial bones (4) Hyoid is not included in skull bones Which of the following is not the bone of cranium (1) Occipital bone (2) Zygomatic bone (3) Ethmoid bone (4) Sphenoid bone In which option the number of bones of two corresponding parts are not the same (1) Thigh and upper arm (2) Sole and Palm (3) Ankle and wrist (4) Leg and arm

9.

10.

11.

12.

13.

14.

15.

16.

17.

The clavicle or collar bone articulates with (1) Glenoid cavity (2) Cervical vertebrae (3) Coxal bone (4) Acromian process Which of the following is an autoimmune disorder (1) Myasthenia gravis (2) Osteoporosis (3) Muscular dystrophy (4) Gout Look at the following sets of bones and the type of joints, and select the correct combination of the two sets A. Atlas and Axis a. Cartilaginous joint B. Two Parietals b. Fibrous joint C. Two pubis bones c. Saddle joint D. First carpal and first metacarpal d. Pivot joint (1) Ab Ba (2) Bb Cc (3) Cb Dc (4) Dc Ad Mark the correct statement (1) All striated muscles are voluntary (2) Visceral muscles are faintly striated (3) Cardiac muscles are not striated (4) All non-striated muscles are involuntary Following is the store house of calcium in muscles (1) Sarcosome (2) Sarcoplasmic reticulum (3) Creatine phosphate (4) Sarcomere Read the following A to D statements and select the one option that contains both correct statements A. Z-line is present in the centre of the light band . B. Thin filaments are firmly attached to the M-line C. The central part of thick filaments, not overlapped by thin filaments is called Z-band D. Light band contains only thin filaments (1) A and D (2) B and C (3) A and C (4) B and D The cross arm that forms the cross bridges during muscle contraction, is formed by (1) HMM (2) LLM (3) Troponin (4) Both 1 and 2 During resting stage the binding site of actin for myosin remains masked by (1) Troponin (2) G actin (3) Tropomyosin (4) Meromyosin The coxal bone consists of (1) Clavicle, coracoid and scapula (2) Maxilla, jugal and squamosal (3) Ilium, ischium and pubis (4) Two clavicles and one interclavicle

762 18.

BIOLOGY There are three blanks in the following statement. Mark the correct option having suitable words for filling the blanks The thin filaments of myofibril contain .......’a’......actin and two filaments of .......’b’......protein along with .......’c’...... protein for masking binding site for myosin 1. 2. 3. 4.

19.

‘a’ 1F 1F 2F 2F

‘b’ Troponin Tropomyosin Troponin Tropomyosin

‘c’ Tropomyosin Troponin Tropomyosin Troponin

Which one of the following is the correct description of a certain part of the normal human skelection ? (1) Parietal bone and the temporal bone of the skull are joined by fibrous joint (2) First vertebra is axis which articulates with the occipital condyles

20.

(3) The 9th and 10th pairs of ribs are called the floating ribs (4) Glenoid cavity is a depression to which the thigh bone articulates. Which one of the following pairs of structures is correctly matched with their correct description ? Structures

Description

(1) Tibia and fibula – Both form parts of knee joint (2) Cartilage and – No blood supply but do cornea require oxygen for respiratory need (3) Shoulder joint – Ball and socket type of joint and elbow joint (4) Premolars and – 20 in all and 3– rooted molars

LOCOMOTION AND MOVEMENT

763

EXERCISE - 2 | Window to Competitive Exams 1.

2.

3.

4.

5.

6.

7.

8.

9.

10.

11.

12.

13.

Longest bone of Frog is [BCECE ‘95] (1) Humerus (2) Tibio-fibula (3) Femur (4) Radio-ulna Almost all muscles ae derived from embryonic [CPMT ‘89; Manipal ‘95] (1) Ectoderm (2) Mesoderm (3) Endoderm (4) All Long uninucleate muscles are found in [CPMT ‘95] (1) Diaphragm (2) Alimentary canal (3) Tongue (4) Eye Smooth muscles occur in [RPMT ‘95] (1) Uterus (2) Artery (3) Vein (4) All of the above Gastrocnemius muscles are found in [DPMT ‘86; RPMT ‘96] (1) Fore arm (2) Chest (3) Thigh (4) Shank Patella bone is derived from [DPMT ‘96] (1) Cartilage (2) Areolar tissue (3) Tendon (4) Ligament Just as there are pseudopodia in Amoeba, there are [MP ‘96] (1) Teeth in rabbit (2) Suckers upon scolex of tapeworm (3) legs in cockroach (4) Spicules in Leucosolenia Pneumatic bones are found in [CBSE ‘96] (1) House lizard (2) Pigeon (3) Flying fish (4) Frog’s tadpole During muscle contraction [MP ‘96] (1) ATP is broken down (2) ATP is formed (3) GTP is broken down (4) None of the above Ankle joint is [Punjab ‘97] (1) Pivot Joint (2) Ball and socket joint (3) Hinge joint (4) Gliding joint Latissimus dorsi muscle is [BHU ‘97] (1) Chest muscle (2) Shoulder muscle (3) Leg muscle (4) Arm muscle Turbinal bones can be traced in [CET Chd ‘97] (1) Trachea (2) Larynx (3) Nasal passage (4) Pelvic girdle Tube feet is the locomatory organ of [MP ‘97] (1) Starfish (2) Jelly fish (3) Crop fish (4) Silver fish

14.

15.

16.

17.

18.

19.

20.

21.

22. 23.

24.

Smooth muscle is [Punjab ‘97] (1) Found in walls of heart only (2) Found in the walls of all the hollow organs except heart (3) Attached to the bones only (4) Found only in the walls of alimentary canal. Myofibrils are made up of [PCS ‘97] (1) Myosin and actin (2) Myosin and troponin (3) Actin and tropomyosin (4) All the above components Striations in the striated muscles are due to (1) absence of myofilaments [PCS ‘97] (2) presence of myofilaments (3) specialized arrangement of myofilaments (4) projections of myosin Number of bones in each leg of human is [CBSE ‘98] (1) 21 (2) 24 (3) 30 (4) 14 Which of the following is the contractile protein of a muscle? [CBSE ‘98] (1) Tubulin (2) Myosin (3) Tropomyosin (4) All of these Which of the following muscles draw the lower jaw, tongue and the head backward? [CPMT ‘98] (1) Proctor (2) Retractor (3) Abductor (4) All of these In mammals the number of cervical vertebrae is [CBSE ‘87; MP ‘94, ‘98] (1) 7 (2) 9 (3) 1 (4) 12 The muscles associated with the heart of insects are [EAMCET ‘98] (1) Alary (2) Radial (3) Striped (4) Pericardial Lower jaw in mammals articulates with [RPMT ‘98] (1) Jugal (2) Alisphenoid (3) Sqamosal (4) Parietal Which of the following is not exclusively supplied with involuntary muscles? [CBSE ‘98] (1) muscles of iris (2) muscles of the ducts of gland (3) muscles of urethra (4) muscular coats of blood vessel Longest ‘visceral’ muscle occurs in [AIIMS ‘88, ‘99] (1) Vas deferens (2) Pregnant uterus (3) Normal uterus (4) Abdomen

764 25.

26.

27.

28.

29. 30.

31.

32.

33.

34.

35.

36.

37.

BIOLOGY Haversian system is diagnostic feature of [CPMT ‘90, 96; KCET ‘94; AIIMS ‘96; EAMCET ‘99] (1) Avian bones (2) Reptilian bones (3) Mammalian bones (4) Bone of all animals Joint between atlas and axis is [CBSE ‘99] (1) Pivot joint (2) Saddle joint (3) Angular joint (4) Hinge joint Astragalus and calcaneum are part of [Punjab ‘99] (1) Fore limb (2) Hind limb (3) Scapula (4) Clavicle Coracoid is component of [BHU ‘99] (1) Fore limb (2) Skull (3) Pectoral girdle (4) Pelvic girdle. Striated muscle fibres are found in [MP ‘99] (1) Urinary bladder (2) Lungs (3) Gallbladder (4) Leg muscles Cardiac muscles are different from that of skeletal muscles as the former are [CPMT ‘99] (1) Striated but involuntary (2) Non striated and involuntary (3) Smooth or unstriated (4) Voluntary in acture Rachet movement is associated with (1) muscle contraction [EAMCET ‘99] (2) ciliary movement (3) flagellar movement (4) protoplasmic movement Synovial fluid is found in [Haryana 2000] (1) cranial cavity (2) spinal cavity (3) immovable joints (4) freely movable joints In mammals the lower jaw is made of [DPMT ‘84, ‘85; BCECE ‘96; MP ‘98; Kerala 2000] (1) Maxilla (2) Dentary (3) Mandible (4) Ethmoid Which one is a bone of skull [CBSE 2000] (1) Atlas (2) Femur (3) Tibia (4) Pterygoid Number of floating ribs in human body is [JIPMER 2000] (1) Two pairs (2) Three pairs (3) Five pairs (4) Six pairs Which yield ATP during muscle contraction? [Harayna 2000; Punjab 2000] (1) Glycogen (2) Creatine phosphate (3) Myoglobin (4) Cholesterol In man coccygeal bone is found in [CPMT 2000] (1) skull (2) pelvic girdle (3) vertebral column (4) pectoral girdle

38.

39.

40.

41.

42.

43.

44.

45.

46.

47.

48.

49.

50.

Hinge joint occurs between [CPMT ‘84; DPMT ‘85; BHU 2000] (1) Humerus and radio-ulna (2) Femur and pelvic girdle (3) Humerus and pectoral girdle (4) Skull and atlas The joint between incus and stapes is [PCS 2000] (1) hinge joint (2) gliding joint (3) pivotal joint (4) ball and socket joint What is the joint between sternum and the ribs in humans? [CBSE 2000] (1) Fibrous joint (2) Gliding joint (3) Cartilaginous joint (4) Angular joint Sutural joints are found between [MP 2000] (1) parietals of skull (2) thumb and metatarsal (3) humerus and radio-ulna (4) glenoid cavity and pectoral girdle Bone marrow is absent in [BHU 2000] (1) Reptiles (2) Fish (3) Amphibia (4) Birds Zygomatic bone is found in [BVP 2000] (1) Pelvic girdle (2) Pectoral girdle (3) Skull (4) Sternum Intercalated discs are found [MP 2000] (1) in striped muscles (2) at the junction of muscles and nerves (3) in cardiac muscles (4) mammalian vertebrae During muscle contraction [AIIMS ‘85; CBSE ‘01] (1) Size of A-bands remains the same (2) Size of H-zone becomes smaller (3) Size of I-bands decreases (4) All the above Which are involved in muscle contraction ? [BHU ‘97; JIPMER ‘98; Wardha ‘01] (1) Ca2+ and Mg2+ (2) Ca2+ and Na+ + + (3) Na and K (4) Mg2+ and K+ Biceps and triceps surround [MP ‘01] (1) femur (2) ulna (3) humerus (4) radius Arytenoid cartilages occur in (1) Nose (2) Hyoid (3) Sternum (4) Larynx Quadriceps and gastrocnemius muscles lie in [MP ‘01] (1) legs (2) hands (3) wrist (4) shoulder Fore-arm is rotated to turn palm downward or backward by muscle [Kerala ‘01] (1) Adductor (2) Abductor (3) Pronator (4) Supinator

LOCOMOTION AND MOVEMENT 51.

52.

53. 54.

55. 56. 57.

58. 59.

60.

61.

62.

63.

The reactions which change lactic acid into glycogen come under [Kerala ‘01] (1) Calvin cycle (2) Cori cycle (3) Krebs Henseleit cycle (4) Hamburger’s reaction Sliding filament theory of muscle contraction was given by [Kerala ‘01] (1) Arnon and Hill (2) Huxley and Pullman (3) Huxley and Huxley (4) None of these Foramen magnum is present in (1) Innominate bone (2) Prootic bone (3) Occipital bone (4) Mandible Which of the following vertebrae are fused [Haryana ‘01] (1) Cervical (2) Sacral (3) Lumber (4) Thoracic Total number of bones found in human skull is (1) 22 (2) 29 [AFMC ‘01] (3) 35 (4) 72 Anisotropic bond is made-up of [AMU ‘01] (1) Myosin filaments (2) Actin filaments (3) Elastin filaments (4) Both (1) and (2) Muscles of alimentary canal are mainly : (1) striated any myogenic [MP ‘01] (2) striated and neurogenic (3) unstriated and neurogenic (4) unstriated and myogenic Acromian process is part of [MP ‘94; BVP ‘02] (1) Vertebral column (2) Pelvic girdle (3) Femur (4) Pectoral girdle Smallest bone in the human body is [CPMT ‘87; MP ‘95; JIPMER ‘02] (1) Stapes (2) Malleus (3) Patella (4) Navicular bone Convexity of one bone articulate with concavity of other bone in [Orissa ‘02] (1) pivot joint (2) hinge joint (3) gliding joint (4) ball and socket joint Spinal cord passes through [DPMT ‘02] (1) Foramen of Monro (2) Foramen ovale (3) Obturator foramen (4) Foramen magnum Number of bones in the adult human body is [AFMC ‘85; Punjab 2000; JIPMER ‘02] (1) 206 (2) 406 (3) 106 (4) 206 Sarcomere is distance between [JIPMER ‘97; BVP 2000; CBSE ‘01; BHU ‘01; MP ‘02; RPMT ‘02] (1) Two I-bands (2) A and I bands (3) Two Z-lines (4) Z and A bands

765 64.

65.

66.

67.

68.

69.

70.

71.

72.

73.

74.

75.

76.

77.

78.

The functional unit of contractile system of a striated muscle is [CBSE ‘98; AMU ‘02] (1) Sarcomere (2) Z-band (3) Sarcosome (4) Myofibril A deltoid ridge occurs in [CBSE ‘90; CPMT ‘02] (1) Radius (2) Ulna (3) Femur (4) Humerus The outer most sheath of connective tissue that surrounds a skeletal muscle is [BHU ‘02] (1) epimycium (2) epimer (2) epimerite (4) epimere Tail vertebrae of birds form [Wardha ‘01, ‘02] (1) Wish bone (2) Chevron bone (3) Urostyle (4) Pygostyle All or none law is associated with [Bihar ‘02] (1) Skeletal Muscle fibre (2) Neuron (3) Cardiac muscle fibers (4) All of these The movable skull bone is [Wardha ‘02] (1) Maxilla (2) Vomer (3) Mandible (4) All the above Number of bones in human appendicular skeleton is (1) 80 (2) 120 [BVP ‘02] (3) 126 (4) 206 Bone formed by ossification of tendon is [MP ‘02] (1) Dermal bone (2) Cartilaginous bone (3) Sesamoid bone (4) Membrane bone The vertebral formula of human adult is (1) C7T12L5S5Cd1 (2) C7T12L (5)S(5)Cd5 (3) C7T12L5S(5)Cd(4) (4) C7T12L5S(5)Cd4 Red muscle fibres are rich in [JIPMER ‘02] (1) Golgi bodies (2) Mitochondria (3) Lysosomes (4) Ribosomes Jaw suspension characteristic of mammals is [RPMT ‘98; MP ‘02] (1) Amphistylic (2) Craniostylic (3) Autodiastylic (4) Hyostylic Smallest muscle is [JIPMER ‘02] (1) Sartorius (2) Stapedius (3) Ocular muscle (4) Mandibular Which of the following is striped muscle but still not voluntary [MAHE ‘02] (1) Cardiac muscle (2) Abdominal (3) Shank (4) Wrist muscles The fundamental repeating unit of a skeletal myofibrial is the [AMU ‘02] (1) sarcomere (2) motor unit (3) sarcoplasmic reticulum (4) myosin cross bridge How many bones are present in our arms? [MHCET ‘03] (1) 32 (2) 60 (3) 45 (4) 25

766 79. 80.

81.

82.

83.

84. 85.

86.

BIOLOGY The number of ‘true ribs’ in a man is (1) 12 pair (2) 7 pair (3) 3 pair (4) 2 pair The joint in our neck which allows us to rotate our head left to right is [MHCET ‘03] (1) pivot joint (2) hinge joint (3) saddle joint (4) ellipsoid joint How many ball and socket joints are present in a human body? [Wardha ‘03; MHCET ‘03] (1) 2 (2) 4 (3) 8 (4) 6 Hinge joint is present in our body between [Vellore ‘03] (1) thumb and trapezium (2) humerus and scapula (3) first and second vertebra (4) humerus and radio-ulna Muscle activity of our body. [Vellore ‘03] (1) decreases BMR (2) decrease venous return (3) increases body temperature (4) reduces blood and lymph flow A muscle bends a part over another. It is [Orissa ‘05] (1) Flexor (2) Extensor (3) Abductor (4) Adductor An acromian process is characteristically found in the: [CBSE’05] (1) Pelvic girdle of mammals (2) Pectoral girdle of mammals (3) Skull of frog (4) Sperm of mammals Which of the following pairs, is correctly matched? [CBSE’05] (1) Hinge joint (2) Gliding joint

- between vertebrae - between zygapophyses of the successive vertebrae (3) Cartilaginous joint - skull bones (4) Fibrous joint - between phalanges 87.

88. 89. 90.

91.

Whch of the following is important for muscle contraction and nerve impulse transmission [BHU ‘05] (1) Ca2+ ions (2) Ca++ and Mg++ ions (3) Mg++ ions (4) Fe2+ ions Which is a high energy compound in muscles? (1) glucose (2) starch [BCECE ‘05] (3) glycogen (4) creatine phosphate The skull of frog is [Kerala ‘05] (1) tricondylic (2) monocondylic (3) di-condylic (4) non-condylic The muscle band that remains unchanged during contraction and relaxation of the skeletal muscle is [Kerala ‘05] (1) I (2) H (3) A (4) Z line During strenous exercise glucose is converted into [BHU ‘05] (1) glycogen (2) pyruvic acid (3) starch (4) lactic acid

92.

Given below is a diagram of the bones of the left human hindlimb as seen from front. It has certain mistakes in labeling. Two of the worngly labelled bones are [AIIMS ‘05]

Femur

Fibula Tibia Tarsals Phalanges (1) tibia and tarsals (2) femur and fibula (3) fibula and phalanges (4) tarsals and femur 93. Inter-articulated disc is found in [BHU ‘05] (1) muscles of arms (2) vertebrae (3) muscles of legs (4) pubic symphysis 94. Which of the following is not syncytial? [MAHE ‘05] (1) cardiac muscle (2) skeletal muscle (3) smooth muscle (4) interstitial muscle 95. The vertebral column is connected to the pelvic girdle in the [MAHE ‘05] (1) coccygeal region (2) sacral region (3) lumbar region (4) cervical region 96. The condition in which a number of nuclei are present in a muscle fibre is called [AMU ‘05] (1) coenocytic (2) syncytial (3) polykaryon (4) endoduplication 97. Acquiring an oxygen debt is evidence that [CPMT ‘05] (1) O2 cannot be stored in tissues (2) aerobic respiration is more complex than glycolysis (3) lactic acid can be converted into glycogen (4) anaerobic process are slower than aerobic processes 98. Structure responsible for formation of sigmoid notch is [CPMT ‘05] (1) olecranon process of humerus (2) olecranon process of femur (3) olecranon process of radius ulna (4) olecranon process of tibia fibula 99. Muscle fatigue is due to [MAHE ‘05] (1) lactic acid (2) citric acid (3) Na+ (4) K+ 100. Lumbar vertebra are found in [CPMT ‘05] (1) neck region (2) abdominal region (3) hip region (4) thorax 101. Which set clearly identify striated muscles ?[CPMT ‘05] (1) cylindrical, syncytial and unbranched (2) spindle, unbranched and uninucleated (3) cylindrical, striped and nucleated (4) cylindrical, striped and branched

LOCOMOTION AND MOVEMENT 102. Contractile tissues have the following features (i) Mesodermal in orign [EAMCET ‘05] (ii) They contain stretch receptors. (iii) Rhythmic contractions are seen in them (iv) They do not fatigue during the life of the animal Which of the above are characteristics of sphincters? (1) All the four (2) Only (i), (ii) and (iii) (3) Only (i), (ii) and (iv) (4) Only (i), (iii) and (iv) 103. The joint where synovial capsule and synovial fluid are lacking is : (1) Carpals [EAMCET ‘05] (2) Pubic symphysis in Females (3) Finger and Toes in Males (4) Femur and pelvis in Females 104. The lactic acid generated during muscle contraction is converted to glycogen in : [EAMCET ‘05] (1) Muscle (2) Kidney (3) Pancreas (4) Liver 105. Largest muscle of human body is [CPMT ‘06] (1) Stapedium (2) Quadriceps (3) Gluteus (4) Masseter. 106. Sigmoid notch is found in [CPMT ‘89,’06] (1) Tibio-fibula (2) Femur (3) Radio-ulna (4) Humerus 107. The contractile protein of skeletal muscle involving ATPase activity is [CBSE ‘06] (1) Myosin (2) a-Actinin (3) Troponin (4) Tropomyosin 108. A cricket player is fast chasing a ball in the field. Which one of the following groups of bones are directly contributing in this movement? [AIIMS’06] (1) femur, malleus, tibia, metatarsals (2) pelvis, ulna, patella, tarsals (3) sternum, femur, tibia, fibula (4) tarsals, femur, metatarsals, tibia 109. In the given diagram of skull, what does “a” represent? [KECT’06]

(a)

767 112. The phosphogen that helps the regeneration of ATP from ADP during muscle contraction in vertebrates is [JK’06] (1) creatinine phosphate (2) arginine phosphate (3) ADP (4) inositol phosphate 113. The peg like process in the axis that allows the rotatory movement of the skull is [JK’06] (1) atlas (2) odontoid process (3) condyles (4) synovial capsule 114. Functional unit of muscle fibre is [Orissa’06] (1) fasciculi (2) muscle (3) fibril (4) none of these 115. Lower jaw of man is made up of [Orissa’06] (1) 1 bone (2) 2 bones (3) no bones, only muscles (4) 3 bones 116. Hensan’s disc are found is [Orissa’06] (1) myofibril of striated muscle (2) myofibril of unstriated muscle (3) myofibril of heart muscle (4) none of the above 117. Heart muscle is sensitive to [Orissa’06] (1) electrical stimuli (2) chemical stimuli (3) mechanical stimuli (4) all of these 118. Thoracic cage in rabbit is made up of [CPMT’06] (1) ribs, vertebral column & diaphragm (2) ribs, diaphragm & sternum (3) vertebral column, diaphragm & sternum (4) ribs, vertebral column & sternum 119. Sigmoid notch is present in [CPMT’06] (1) radius (2) ulna (3) humerus (4) femur 120. Innominate is [CPMT’06] (1) a nerve and an artery (2) a nerve and a vein (3) a vein and an artery (4) a part of skeleton & an artery 121. The number of vertebrae present in cervical, thoracic, lumbar, sacral and coccyx regions respectively are [Kerala’06] (1) 12, 7, 5, 1, 1 (2) 1, 7, 5, 12, 1 (3) 7, 5, 1, 12, 1 (4) 7, 12, 5, 1, 1 122. Look at the diagram given below. [Kerala’06] e

d a

b

(1) frontal bone (2) temporal bone (3) occipital bone (4) parietal bone 110. Hyoid bone is located at the [HPMT’06] (1) top of the buccal cavity (2) floor of the buccal cavity (3) front of the skull (4) behind the skull 111. During contraction of skeletal muscle Ca++ bind to [HPMT’06] (1) myosin ATPase (2) tropomyosin (3) actin (4) troponin

c

Parts labelled as ‘a’, ‘b’, ‘c’, ‘d’ and ‘e’ respectively indicate Pa (1) ilium, femur, tibia, pubis and sacrum (2) pubis, tibia, femur, ilium and sacrum (3) ilium, femur, tibia, pubis, and sacrum (4) pubis, femur, tibia, ilium and sacrum

768

BIOLOGY

123. Which one of the following items gives its correct total number ? [CBSE’08] (1) Cervical vertebrae in humans – 8 (2) Floating ribs in humans – 4 (3) Amino acids found in proteins – 16 (4) Types of diabetes – 3 124. Which one of the following is the correct matching of three items and their grouping category ? [CBSE’09] Items (1) cytosine, uracil, thiamine (2) malleus, incus, cochlea (3) ilium, ischium,

131. Three of the following pairs of the human skeletal parts are correctly matched with their respective inclusive skeletal category and one pair is not matched. Identify the nonmatching pair. [CBSE Final’ 11]

Group –

pyrimidines

–

ear ossicles

–

coxal bones of pelvic girdle muscle proteins

(4) actin, myosin, – rhodopsin 125. Elbow joint is an example of : [CBSE’09] (1) ball and socket joint (2) pivot joint (3) hinge joint (4) gliding joint 126. The example of pivot joint is [DPMT’ 10] (1) Hip joints (2) Metacarpophalangeal joints (3) Ankle joints (4) Radioulnar joints 127. The major function of the intervertebral discs is to [DPMT’ 10] (1) Absorb shock (2) String the vertebrae together (3) Prevent injuries (4) Prevent hyperextension 128. The membranous areas between the cranial bones of the fetal skull are called [DPMT’ 10] (1) Areolas (2) Foramina (3) Sutures (4) Fontanelle 129. Which one of the following pairs of structures is correctly matched with their correct description? [CBSE Final’ 10] Description Both form parts of knee joint (2) Cartilage and cornea – No blood supply but do require oxygen for respiratory need (3) Shoulder joint and elbow Ball and socket type of joint – joint (4) Premolars and molars – 20 in all and 3– rooted

132.

133.

134.

135.

Structures (1) Tibia and fibula –

130. Which one of the following is the correct description of a certain part of a normal human skeleton? [CBSE Final’ 10] (1) Parietal bone and the temporal bone of the skull are joined by fibrous joint (2) First vertebra is axis which articulates with the occipital condyles (3) The 9th and 10th pairs of ribs are called the floating ribs (4) Glenoid cavity is a depression to which the thigh bone articulates

Pairs of skeletal parts Category Humerus and ulna Appendicular skeleton Malleus and stapes Ear ossicles Sternum and Ribs Axial skeleton Clavicle and Glenoid Pelvic girdle cavity The clavicle articulates with ____ of scapula (1) Acromion process [DPMT’ 11] (2) Glenoid cavity (3) Acetabulum cavity (4) Ball and socket joint Select the correct statement regarding the specific disorder of muscular or skeletal system : [CBSE’ 12] (1) Myasthenia gravis - Auto immune disosrder which inhibits sliding of myosin filaments (2) Gout - inflammation of joints due to extra deposition of calcium (3) Muscular dystrophy - age related shortening of muscles (4) Osteoporosis - decrease in bone mass and higher chances of fractures with advancing age The H- zone in the skeletal muscle fibre is due to [AIPMT (NEET)’13] (1) The absence of myofibrils in the central portion of A- band (2) The central gap between myosin filaments in the Aband (3) The central gap between actin filaments extending through myosin filaments in the A- band (4) Extension of myosin filaments in the central portion of the A- band Select the correct statement with respect to locomotion in human [AIPMT (NEET)’13] (1) A decreased level of progesterone causes osteoporosis in old people (2) Accumulation of uric acid crystals in joints causes their inflammation (3) The vertebral column has 10 thoracic vertebrae (4) The joint between adjacent vertebrae is a fibrous joint The characteristics and an example of a synovial joint in humans is [AIPMT (NEET)’13] Characteristics Examples (1) Fibrous cartilage between two Knee joint bones, limited movements (2) Fluid filled between two joints, Skull bones provides cushion (3) Fluid filled synovial cavity Joint between between two bones atlas and axis (4) Lymph filled between two bones, Gliding joint limited movement between carpals (1) (2) (3) (4)

136.

LOCOMOTION AND MOVEMENT 137. Select the correct matching of the type of the joint with the example in human skeletal system: [AIPMT’14] Type of joint Example (1) Cartilaginous joint Between frontal and parietal (2) Pivot joint Between third and fourth cervical vertebrae (3) Hinge joint Betweenhumerus and pectoral girdle (4) Gliding joint Between carpals 138. Stimulation of muscle fibre by a motor neuron occurs at: (1) The neuromuscular junction [AIPMT’14] (2) The transverse tubules (3) The myofibrils (4) The sarcoplasmic reticulum 139. The sliding filament theory can be best explained as: [AIPMT’15] (1) When myofilaments slide pass each other Actin filaments shorten while myosin filament do not shorten (2) Actin and Myosin filaments shorten and slide pass each other (3) Actin and Myosin filaments do not shorten but rather slide pass each other (4) When myofilaments slide pass each other, Myosin filaments shorten while Actin filaments do not shorten 140. In glenoid cavity, articulates: [AIPMT’15] (1) Clavicle with acromian (2) Scapula with acromian (3) Clavicle with scapula (4) Humerus with scapula 141. Which of the following joints would allow no movement? [RE-TEST AIPMT’15] (1) Cartilaginous joint (2) Synovial joint (3) Ball and socket joint (4) Fibrous joint

769 142. Which of the following is not a function of the skeletal system? [RE-TEST AIPMT’15] (1) Storage of minerals (2) Production of body heat (3) Locomotion (4) Production of erythrocytes 143. The amoeboid movement results from: [AMU’15] (1) Interactions among actin, myosin and ATPs (2) Coordinated beats of cilia (3) Whip like action of flagella (4) Action of mitotic spindle, similar to what happens during mitosis and meiosis 144. Gliding joint is present between the: [KERALA’15] (1) Carpals (2) Humerus and pectoral girdle (3) Carpals and metacarpals of thumb (4) Knee 145. The lumber region of vertebral column in man is made up of: [KERALA’15] (1) 1- fused vertebra (2) 7- vertebrae (3) 12- vertebrae (4) 5- vertebrae 146. The skeletal muscle fibre is a ‘syncytium’, which means it is: [KERALA’15] (1) Made up of many fibres (2) Made up of many proteins (3) Long and slender (4) Swollen in the middle with tapered ends (5) Multinucleated

770

BIOLOGY

EXERCISE - 3 | Test Yourself 1. 2.

3.

4.

5.

6.

7. 8.

9. 10.

11.

Which muscle protein acts as ATPase? (1) Actin (2) Troponin (3) Myosin (4) Tropomyosin Z-line in myofibrils is present (1) In Dark band (2) Between dark and light band (3) In Light band (4) In the middle of sarcomere Eye-lid muscles have (1) Thick fibres with abundant mitochondria (2) Thick fibres without myoglobin (3) Thin fibres with myoglobin (4) Thin fibres with lesser mitochondria Actin protein occurs in two forms (1) Polymeric F- actin and monomeric G- actin (2) Monomeric F- actin and polymeric G-actin (3) The tail and a head (4) F-actin and G- actin, but both globular Intercalated discs are present in between (1) Mammalian vertebrae (2) Epithelial cells (3) Cardiac muscle fibres (4) Isotropic bands All are the properties of single unit of involuntary muscle except (1) Own pacemaker (2) Supplying nerve can increase or decrease the contraction of muscle (3) Muscle contraction depends on supplying nerve which initiates the contraction of muscle (4) All the above Movement at Atlanto-occipital joint is an example of (1) Class I lever (2) Class II lever (3) Class III lever (4) Hinge lever Sarcosome in the muscles is the name for (1) The functional unit (2) Creatine phosphate-granules (3) Mitochondria (4) Neuromotor junction Anisotropic band is (1) Thick and dark (2) Thin and dark (3) Thick and light (4) Thin and light The muscle fibres in hair roots and ciliary muscles (1) Are multi-unit type (2) Are single-unit type (3) Are striated (4) Contract together A-band of the Myofibril contains (1) Only thick filaments (2) Only Thin filaments (3) Both Thick and thin filaments (4) No filaments

12. 13.

14.

15. 16.

The Krause membrane is associated with: (1) Simple epithelium (2) Nervous tissue (3) Muscular tissue (4) Connective tissue A longitudinal haversian canal carrying blood capillary can be best seen in the bones of (1) Frog (2) Fish (3) Crocodile (4) None of the above Troponin (1) Produces sliding movement of microtubules (2) Contains globular head (3) Binding to Ca+2 produces skeletal muscle contraction. (4) Covers the active site of actin Humerus differs from the femur in having: (1) Sigmoid notch (2) Trochanter (3) Deltoid ridge (4) None of these Match the locomotory structure of column I with the name of phylum in column II Column II I. Mollusca II. Echinodermata III. Protozoa IV. Annelida V. Arthropoda (1) A-V, B-IV, C-III, D-II (2) A-IV, B-I, C-III, D-II (3) A-V, B-I, C-III, D-II (4) A-IV, B-II, C-III, D-V Three basic types of movements for locomotion are (1) Ciliary, flagellar and muscular (2) Brownian, ciliary and muscular (3) Ciliary, flagellar and amoeboid (4) Amoeboid, ciliary and muscular Jaw bones develop from (1) Neurocranium (2) Chondrocranium (3) Splanchnocranium (4) Notochord Which bony process provides attachment to the muscles of diaphragm? (1) Odontoid process (2) Coronary process (3) Xiphoid process (4) Zygapophysis ‘Uncinate process’ is associated with (1) Skull (2) Ribs (3) Pelvic girdle (4) Hind limb The wish bone of the birds is derived from: (1) Skull (2) Pectoral girdle (3) Pelvic girdle (4) Hind limb Joint between lower jaw and the skull is: (1) Hinge joint (2) Fixed joint (3) Imperfect joint (4) Saddle joint Acromian process in human is present in: (1) Skull (2) Pelvic girdle (3) Axis (4) None of these Synsacrum in birds is formed by the fusion of the vertebrae of (1) Hip region only (2) Abdominal and hip regions (3) Abdominal, hip and tail regions (4) Chest, abdominal, hip and tail regions A. B. C. D.

17.

18. 19.

20. 21. 22. 23. 24.

Column I Parapodia Muscular foot Pseudopodia Tube feet

LOCOMOTION AND MOVEMENT 25. 26. 27. 28.

29. 30. 31.

32. 33. 34. 35.

36.

37. 38. 39.

40. 41.

The wrist bones are called (1) Metatarsals (2) Metacarpals (3) Tarsals (4) Carpals Innominate is the bone of (1) Sternum (2) Pectoral girdle (3) Hip girdle (4) Hind limb Ribs are (1) Membranous bones(2) Sesamoid bones (3) Cartilagenous bones(4) Dermal bones The strength of contraction of an entire skeletal muscle is dependent on the (1) N u m b e r o f m u s c l e f i b r e s t h a t c o n t r a c t simultaneously (2) Frequency of contraction of each muscle fibre (3) Number of active cross bridges in each muscle fibre (4) All the above Heterocoelous centrum is present in the vertebrae of (1) Fishes (2) Aves (3) Reptiles (4) Mammals Mark the incorrect match (1) Hyoid - tongue bone (2) Sternum - breast bone (3) Coracoid - collar bone (4) None of these Accumulation of uric acid crystals in the synovial joint causes (1) Rheumatoidal arthritis (2) Gout (3) Osteoarthritis (4) All of these Which bone does not articulate with the other bones (1) Ear ossicle (2) Hyoid bone (3) Mandible (4) Occipital bone Heel is formed by (1) Clavicle (2) Calcaneum (3) Corocoid (4) Talus Cell to cell conduction is not possible in (1) Skeletal muscle (2) Cardiac muscle (3) Smooth muscle (4) All the above Which part of sarcoplasmic reticulum is related to End plate potential (1) Cisterns (2) L-tubule (3) T-tubule (4) All the above Patellar groove and bicipetal groove are present respectively in (1) Femur and Humerus (2) Femur and ulna (3) Tibia and Humerus (4) None of these The skull of which animal is monocondylic (1) Snake (2) Pigeon (3) Varanus (4) All of these The longest smooth muscle in the body is (1) Myometrium of uterus (2) Rectus abdominis (3) Masseter (4) Sartorius Mammalian ribs are (1) Single headed (2) Double headed with uncinate process (3) Double headed without uncinate process (4) Double headed with one head attached to sternum and other to vertebral column Following mammal does not have 7- cervical vertebrae (1) Giraffe (2) Camel (3) Dolphin (4) Sea cow What is cross bridge (1) Myosin molecule (2) Actin molecule (3) Actomyosin complex (4) During muscle contraction extra protein layer present in between actin and myosin molecule

771 42. 43.

44.

45. 46.

47.

48.

49. 50.

51. 52.

53.

54. 55. 56.

57. 58.

Largest and heaviest bone of human body is (1) Tibia (2) Humerus (3) Femur (4) Hip bone Which type of muscles in vertebrates help in locomotion? (1) Involuntary and striated (2) Voluntary and striated (3) Involuntary and unstriated (4) All of these Which of the following animal utilizes water current for locomotion? (1) Tadpole (2) Sponge (3) Shark (4) Star fish Which of the following bone is called breast bone? (1) Sacrum (2) Clavicle (3) Scapula (4) Sternum Vertebral column in human has (1) One primary and one secondary curves (2) Two primary and one secondary curves (3) Two primary and two secondary curves (4) One primary and two secondary curves Capitate, hamate, trapezium and trapezoid are the names of (1) Carpals of proximal row (2) Carpals of distal row (3) Tarsals of proximal row (4) Tarsals of distal row Total number of movable bones (exculing hyoid) in human skull are (1) 1 (2) 4 (3) 6 (4) 7 Total number of carpals in human skeleton are (1) 8 (2) 16 (3) 7 (4) 14 Foramen transversarium, also known as vertebro- arterial canal, is present in all (1) Cervical vertebrae (2) Sacral vertebrae (3) Lumber vertebrae (4) Caudal vertebrae Zygomatic bone in skull is also known as (1) Jaw bone (2) Chin bone (3) Eye brow bone (4) Cheek bone In the following disorder the synovial membrane starts secreting abnormal granules called Pannus which cause erosion of cartilage (1) Osteoarthritis (2) Gouty arthritis (3) Rheumatoidal arthritis (4) Osteoporosis The striated muscle fibres are united in parallel bundles, the fasciculi. Each fasciculus is in turn surrounded by a connective tissue sheath known as (1) Perimysium (2) Epimysium (3) Endomysium (4) Exomysium. Sternoclavicular joint is (1) Angular joint (2) Cartilagenous joint (3) Gliding joint (4) Fibrous joint Median atlanto axial joint is (1) Ball & Socket type (2) Hinge type (3) Pivot type (4) Saddle type Which of the following animal does not have muscle fibres but shows locomotion (1) Star fish (2) Ascaris (3) Hydra (4) Sponge Gorilla rib, found some times in man, is (1) A false rib (2) Extra floating rib (3) Cervical rib (4) Not a rib Which of the following represents the lever of the Third Order? (1) Atlanto-occipital joint (2) Elbow joint (3) Ankle joint (4) Toes joint

772 59.

60.

61.

BIOLOGY Mark the true statement (1) Bicep is an extensor muscle (2) Muscle tetanus is sustained contraction of muscle (3) Creatinine is the energy rich compound of the skeletal muscles of the vertebrates (4) None of these The joint between two pubis bones of hip girdle is (1) Fixed type (2) Synovial joint (3) Imperfect joint (4) Fibrous joint Wish bone in birds is formed from the bones of (1) Shoulder girdle (2) Hip girdle (3) Keeled sternum (4) Skull bones

62. 63. 64. 65. 66.

Which of the following animal has no skeleton? (1) Sponge (2) Butterfly (3) Jelly fish (4) Star fish Caudal vertebrae in birds are fused to form (1) Pygostyle (2) Furcula (3) Coccyx (4) Urostyle Fabellae bones are related to (1) Knee joint (2) Neck joint (3) Ankle joint (4) Wrist joint Following muscles turn the sole of the foot outward (1) Pronator (2) Invertor (3) Retractor (4) Evertor The joint between teeth and the jaw bone is called (1) Fibrous joint (2) Gymphoseal joint (3) Cartilagenous joint (4) Synovial joint

LOCOMOTION AND MOVEMENT

773

ANSWER KEY EXERCISE 1 : NCERT BASED QUESTIONS

136. (3)

137. (4)

138. (1)

139. (3)

140. (4)

142. (2)

143. (1)

144. (1)

145. (4)

1.

(2)

2.

(1)

3.

(4)

4.

(3)

5.

(2)

141. (4)

6.

(4)

7.

(2)

8.

(3)

9.

(4)

10.

(1)

146. (5)

11.

(4)

12.

(4)

13.

(2)

14.

(1)

15.

(1)

16.

(1)

17.

(3)

18.

(4)

19.

(1)

20.

(2)

EXERCISE 2 : WINDOW TO COMPETITIVE EXAMS

EXERCISE 3 : TEST YOURSELF 1.

(3)

Troponin has maximum affinity for calcium.

2.

(3)

Z-line is also known as Krause membrane. These fibres are white and develop fatigue easily.

1.

(2)

2.

(2)

3.

(2)

4.

(4)

5.

(4)

3.

(2)

6.

(3)

7.

(3)

8.

(2)

9.

(1)

10.

(3)

4.

(1)

11.

(2)

12.

(3)

13.

(1)

14.

(2)

15.

(4)

16.

(3)

17.

(3)

18.

(2)

19.

(2)

20.

(1)

21.

(1)

22.

(3)

23.

(3)

24.

(4)

25.

(3)

5. 6. 9.

(3) (3) (1)

Mammalian vertebrae have inter-vertebral discs. 7. (1) 8. (3) The length of A-band is about 1.5 µ .

10.

(1)

Both the muscles are of smooth type.

26.

(1)

27.

(2)

28.

(3)

29.

(4)

30.

(1)

10.

(3)

31.

(1)

32.

(4)

33.

(3)

34.

(4)

35.

(1)

12.

(3)

This membrane is also called as Z-band.

36.

(1)

37.

(3)

38.

(1)

39.

(1)

40.

(3)

13.

(4)

41.

(1)

42.

(4)

43.

(3)

44.

(3)

45.

(4)

Haversian canal can be seen in the bones of mammals.

46.

(1)

47.

(3)

48.

(4)

49.

(1)

50.

(3)

14.

(4)

15.

17.

(4)

The flagellum is an enlarged version of cilium.

51.

(2)

52.

(3)

53.

(3)

54.

(2)

55.

(2)

18.

(3)

56.

(4)

57.

(4)

58.

(4)

59.

(1)

60.

(4)

Cranium or brain box develops from neurocranium.

61.

(4)

62.

(1)

63.

(3)

64.

(1)

65.

(4)

19.

(3)

Xiphoid process is present at the posterior end of sternum.

66.

(1)

67.

(4)

68.

(4)

69.

(3)

70.

(3)

20.

(2)

Uncinate process is present in the ribs of birds.

71.

(3)

72.

(3)

73.

(2)

74.

(2)

75.

(2)

21.

(2)

76.

(1)

77.

(1)

78.

(3)

79.

(2)

80.

(1)

‘Wish bone’, also called ‘bone of marry thought’ is 1-interclavicle fused with 2-clavicles.

81.

(4)

82.

(4)

83.

(3)

84.

(1)

85.

(2)

22.

(4)

This joint is also known as tempo-mandibular joint.

86.

(2)

87.

(1)

88.

(3)

89.

(3)

90.

(3)

23.

(4)

This process is present in pectoral girdle.

91.

(4)

92.

(3)

93.

(2)

94.

(3)

95.

(2)

24.

(4)

Synsacrum in fowl consists of 14-16 vertebrae.

96.

(2)

97.

(1)

98.

(3)

99.

(1)

100. (2)

25.

(4)

Carpals are eight (4+4) in number in each wrist.

26.

(3)

Hip girdle has two innominate bones, each formed by the fusion of ilium, ischium and pubis.

(3)

16.

(2)

101. (1)

102. (2)

103. (2)

104. (4)

105. (3)

106. (3)

107. (1)

108. (4)

109. (2)

110. (2)

27.

(3)

28.

111.

(4)

112. (1)

113. (2)

114. (4)

115. (1)

29.

(2)

This centrum is called as saddle shaped also.

116.

(1)

117. (4)

118. (4)

119. (1)

120. (4)

30.

(3)

The collar bone is clavicle not coracoid.

121. (4)

122. (4)

123. (2)

124. (3)

125. (3)

31.

(2)

Gout is a sex controlled (autosomal) trait.

126. (4)

127. (1)

128. (4)

129. (2)

130. (1)

32.

(2)

131. (4)

132. (1)

133. (4)

134. (2)

135. (2)

33.

(2)

34.

(1)

(4)

Calcaneum/ calcaneus is the largest tarsal bone.

774 35.

BIOLOGY (4)

T(Transverse) and L(Longitudinal) - tubule system are the parts of Endoplasmic reticulum. Cisternae are the dialated part of L-tubules. L-tubules store and release Ca++ after stimulation by Acetylcholine.

36.

(1)

37.

(4)

The skull in mammals and amphibians is Dicondylic.

38.

(2)

Masseter, the Jaw muscle, is the strongest one.

39.

(3)

The uncinate process is present in the ribs of birds.

40.

(4)

Sea-cow belongs to order Sirenia. Sloth (Order Edentata) too does not have 7- cervical vertebrae. (3)

52.

(3)

In Gouty arthritis the uric acid salts are deposited in the synovial fluid.

53.

(1)

The epimysium is the outermost connective tissue sheath of the muscle.

54.

(3)

55.

56.

(3)

Hydra has epithelio- and endothelio- muscular cells.

57.

(2)

This is 13th rib, present in some persons.

58.

(2)

Ankle joint and atlanto-occipital joint represent the lever of II and I order.

59.

(2)

The single contraction in the muscle fibre is called muscle twitch.

60.

(3)

This joint is also known as cartilaginous joint.

61.

(1)

Two clavicles fuse with one inter-clavicle to form ‘Wish bone’ or ‘Bone of merry thought’.

62.

(3)

Sponge and starfish both have spicules while butterfly has chitinous exoskeleton.

(3)

41.

(3)

42.

43.

(2)

Smooth muscles are present in visceral organs.

44.

(4)

Sponges are sessile.

45.

(4)

The clavicle is commonly called collar bone

46.

(3)

The anterior most curve (1st) is secondary.

47.

(2)

The proximal row is formed by Pisciform, Lunate Scaphoid and Triquetral.

63.

(1)

Caudal vertebrae in human are fused to form coccyx.

48.

(1)

The only movable bone in skull is mandible.

64.

(1)

49.

(2)

50.

Two smaller sesamoid bones, other than patella, which lie opposite to it, are Fabellae bones.

65.

(4)

66.

(1)

(1)

51.

(4)

It is a fixed or immovable joint.

Chapter

21

Neural Control & Coodination (Part-I & II)

Part-I : Neural Control & Coordination While going through the chapter pay special attention to the following – Terms and Definitions – 1. Impulse 4. Reflex 7. Amygdala

2. 5.

Refractory Period Synapse

3. 6.

Iter Gray matter

Differences – 1. Depolarization and Repolarization 2. Synaptic fatique and Synaptic delay 3. Excitatory and Inhibitory Neurotransmitters 4. Corpora Bigemina & Corpora Quadrigemina 5. Broca’s centre and Broadman’s centre 6. Electrical synapses and Chemical synapses 7. Conditioned and Unconditioned reflexes 8. Dorsal root and Ventral root of spinal nerves Structures – 1. Corpus callosum 4. Limbic system Disorders – 1. Parkinson’s disease 3. Alzheimer’s disease Nerves – 1. Hypoglossal 4. Sensory nerve

2. 5.

Choroid plexus Colliculi

2.

Meningitis

2. 5.

Pathetic Coccygeal

3. 6.

3. 6.

Foramen of Monro Pons

Dentist’s nerve Cholinergic



Nervous tissue is Ectodermal in origin.



Protozoans and Porifers do not have nervous tissue.



Nervous tissue first evolved in the members of phylum Coelenterata (Cnidaria). The nerve cells in this group are non-polarized (i.e., the dendrites and axons are not differentiated).



In non-chordates the nerve cord is ventral and solid.

At a Glance                                    

Conduction of nerve impulse Conduction through axon

Conduction through synapse Velocity of nerve impulse Central nervous system Human brain Fore brain

Functions of cerebrum

Functions of hypothalamus Mid brain

Hind brain

Cerebellum Pons

Medulla oblongata

Peripheral nervous system Cranial nerves

Spinal cord & spinal nerves Re�lex action

Autonomous nervous system Sympathetic nervous system

Para sympathetic nervous system Disorders of the nervous system Receptors

Human eye Scleroid

Choroid (uvea) Retina

Glands

Disorders of the eye Human ear

External ear Middle ear

Internal ear Tongue Nose

Other sensory structures

776

BIOLOGY 

In chordates the nerve cord (spinal cord) is dorsal and tubular (hollow).



Neuron (nerve cell) is the structural and functional unit of the nervous system.



A multi-polar neuron has at least two dendrites (For detailed structure of Neuron, please refer Chapter 7, Animal Tissues).

CONDUCTION OF NERVE IMPULSE Impulse – It is a wave of depolarization The conduction of nerve impulse is an ‘electrochemical phenomenon’. It can be studied in two parts. (1) Conduction through axon (2) Conduction through synapse

Conduction through axon 

Axon-membrane, called axolemma, contains voltage gates for sodium and potassium ions. In myelinated fibres (having Myelin sheath) these voltage gates are present only at the nodes while in non-myelinated fibres, such gates are distributed all along the axon-membrane.



The Sodium (Na+) and Potassium (K+) pump channels are also distributed similarly in the axolemma. For the expense of 1- ATP, 3-Na+ move out into the extra cellular fluid (ECF) and 2-K+ move into the intra cellular fluid (ICF).



Sodium ions (Na+) are maximum in ECF (~150 m. mol/Lit. or 10 times of Na+ in ICF), while K+ are maximum in ICF (~150 m.mol/Lit. or 30 times of K+ in ECF).



Axolemma is little permeable for K+ but almost impermeable for Na+.

(a) Resting Stage •

The potential difference in an average sized neuron, at resting stage, is ‘–70mV’.

•

Outer surface of axolemma, facing ECF, has positive (+ve) charge while the inner surface, facing ICF, has –ve charge (the sign used in potential difference is the charge inside the membrane or in axoplasm).

•

The potential difference is maintained with the help of Na+ - K+ pump.

•

The resting potential difference in RBCs is – 10mV ; in cardiac muscles it is – 90mV and in skeletal muscles the value is approximately – 100mV.

•

Na+ and K+ voltage gates during this stage remain closed.

(b) Action Potential There are two phases of action potential (i) Depolarization • The ‘threshold value’ for generating nerve impulse is –50mV to –55mV. If the stimulus is of lesser intensity the impulse is not generated. •

All neurons follow ‘All or none law’. According to which either the impulse will not be generated at all or, if generated, it will be generated to its full magnitude. There are no weak impulses.

•

Due to a given stimulus if the potential difference reaches to the threshold value, Na+ gates open and sodium enters into axoplasm (Na+-Influx) according to concentration gradient.

•

Due to movement of Na+ into axoplasm, reverse polarization develops, i.e. outer surface becomes negatively charged and inner surface becomes positively charged.

•

The potential difference from -55mV goes to 0 and then reaches up to +40mV (Spike potential potential).

•

During depolarization the K+ gates remain closed.

NEURAL CONTROL & COORDINATION (PART-I & II) +

+

+

+

Na

Na+

+

Na +

Na

Na

+

K

+

K +

–

–

+

K

+

K

+

Na

+

+ Na + Na Na + K 3Na K + + + + + + + + + – – – – – +– – – – 2K + + K K

Na

+

K

Axoplasm

+

Na – – – –

–

+ +

+

– –

–

+ +

+

Na

Na –

– –

influx

+

+

+

–

+

+ + + ++ Na + Na+ Na Na

Na

Na

– –

+ –

+

+ –

Na + –

+

+ –

+ –

Na

K

+

+ –– –

Depolarization

+

– – K

+

– – – ++ + ++ K K

+

Na

Na

– +

+

– –

– Na

Na –

+ ++ + + K

+

+

– ++ + K

Repolarization

(+ 40mV)

Resting stage

+

Na

+

++ K

+

– – – Na

– – +

+

Na + K Na + + + + K K K K K + + + + + + + + +

+

Na

+ + + + + + + + Axolemma + ++ K 3Na Na Na–K voltage gate voltage gate pump channel +

K +

– –

+

+

+

2K Na – –

777

(– 70mV)

(– 70mV)

Fig. 21.1 Threshold value

(ii)

RepolarizationIt is completed in two phases First phase• In this phase the Na+ gates are closed and K+ (voltage) gates open. •

K+, according to concentration gradient move from the axoplasm (ICF) into ECF (K+-Efflux).

•

The outer surface facing ECF develops +ve charge while inner surface develops –ve charge.

•

The charges are similar to resting potential, but here the +ve charge is because of more K+, not Na+, as in resting stage. Second phase• During this phase Na+ - K+ pump again becomes active and ionic distribution, similar to resting stage, across the membrane (axolemma) is restored. +

– 50mV

– 70mV – 80 mV (Hyperpolarization)

K gates open + + + + + – – – – –

+ + + + – – – –

– – – – + + + + (4)

– – – – + + + + + (3)

– – – – + + + + +

0

+

+ + + + – – – –

+ + + + + – – – – –

+ 40

Na gates open

– – – – + + + + (1)

Resting stage (–70mv)

Repolarization (–70mv)

Depolarization (+40mv)

(2)

Resting stage (–70mv)

Conduction of nerve impulse (Arrows indicating direction)

Fig. 21.2 Never impulse Direction

Refractory Period It is the minimum time period between two consecutive stimuli which can generate impulses. It can also be defined as the time period, required for the repolarization or recovery of resting potential. Connecting Concepts 1 Refractory period in average neuron = sec. or 1.0 ms (mili second)  If the stimulus is given in the middle 1000

of an axon, the impulse travels in both

•

The first phase of repolarization in the above case is called ‘Absolute refractory the direction. But through synapse, the period’ while the second phase is called ‘Relative refractory period’. conduction is one way only.

•

In absolute refractory period the second impulse (no matter of what magnitude) can not be generated. However, in relative refractory period, an impulse can be generated if the stimulus is of greater magnitude.

Conduction of impulse through synapse The junction between two neurons is called Synapse. It includes presynaptic membrane of terminal button of previous axon, a synaptic cleft, and a post-synaptic membrane of dendrite. There are two types of synapses in human (i) Electrical synapses – In such synapses the synaptic cleft is ~ 0.2nm and the conduction through such synapse is similar to that of axon.

778

BIOLOGY

•

The post synaptic membrane contains receptors to which the neurotransmitter binds for opening the channels.

•

When the impulse reaches terminal button of the axon the Ca++ gates open and calcium influx occurs through presynaptic membrane.

•

The synaptic vesicles become active and rupture after coming in contact of presynaptic membrane. The neurotransmitter is released by exocytosis into synaptic cleft.

•

The neurotransmitter binds with the receptors of post synaptic membrane and Na+ gates open. Na+ influx occurs and impulse (depolarization wave) is generated.

Receptor +

Na

+

Na influx

–

+

Ca

+ –

+

+

– + – +

Mitochondria

2+

–

– +

– +

– 2++ – + Ca 2+ Ca

–

Presynaptic vesicles

Synaptic cleft (20nm)

+ –

Connecting Concepts  The amount of neurotransmitter released in such cases is proportionate to the amount of Ca++ influx

Chemical synapses – In such synapses the synaptic cleft is of ~ 20nm and the transmission through such synapses is different from that of axons as the transmission here, requires a chemical neurotransmitter. The most common neurotransmitter is Acetylcholine. • The terminal buttons or synaptic knobs contain synaptic vesicles filled with a neurotransmitter. (The advantage of chemical synapses is that the nature of neurotransmitter can be different in different synapses). • In such transmission, in place of voltage gates, there are Ligand-gated channels present.

–

(ii)

2+

2+

–

+

Ca

Ca

2+

+ Ca – + – –+

Na 2+

Ca

Na

+

+

Neurotronsmitter

Connecting Concepts  In Myasthenia gravis, an autoimmune disease of skeletal muscles, the antibodies are developed against the acetylcholine receptors of neuromotor junctions.

Fig. 21.3 Synaptic transmission

•

Na+

As the gates open, the neurotransmitter (here acetylcholine) gets immediately destroyed by an enzyme Acetylcholinesterase, secreted from post synaptic membrane.

In case of another neurotransmitter, i.e., nor-adrenaline, the enzyme is mono-amino oxidase. Synaptic delay – It is the time taken in influx of Ca++ , release of neurotransmitter and binding Connecting Concepts of neurotransmitter with the receptors.  The neurons never undergo such Synaptic fatigue – It develops when acetylcholine is completely exhausted. During this period fatigue. The fatigue only develops the impulse can not be transmitted. at the junction of two neurons (i.e., (The neurotransmitter is formed by the Nissl’s granules in the cell body of neurons. From here synapses). it reaches to synaptic vesicles of the terminal buttons). •

Velocity of Nerve Impulse In frog it is ~ 25m / sec. in myelinated (or medullated) fibers and ~ 0.5m / sec. in non-myelinated fibers. In human the velocity of nerve impulse in myelinated fibers is ~ 100m to 120m /sec, and in non-myelinated fibres it is ~ 2m/sec. The velocity of nerve impulse depends upon 3-factors. 1. Presence or absence of myelin sheath. 2. Number of Synapses. 3. The cross section area (diameter) of the nerve fibre.

NEURAL CONTROL & COORDINATION (PART-I & II) (i)

(ii)

Myelin sheath – The conduction of nerve impulse through myelinated fibers is called Saltatory conduction as the impulse jumps (Saltare-to jump) from node to node. The conduction through myelinated fibers is faster and economical because depolarization developes in lesser area (only at the nodes). Synapses – There is delay at every synapse. Therefore, more time is taken if the number of synapses is greater and the velocity is thus reduced. 1 Velocity ∝ No. of synapses

(iii) Diameter – If the cross section area is more the number of voltage gates will also be more and depolarization will be faster and velocity will be greater. Velocity ∝ diameter.

Neurotransmitters – 2 types (i)

Excitatory neurotransmitter – Impulse travels from one neuron to the other undiminished through such neurotransmitter. eg. Acetylcholine, Adrenaline, Nor-adrenaline and Serotonin etc. (ii) Inhibitory neurotransmitter - Such neurotransmitter check the transmission of nerve impulse from one neuron to the other. They increase the permeability of axolemma for chloride ions instead of Na+ ions, or open the K+ (voltage) gates. Therefore, in place of depolarization, hyperpolarization develops and impulse is not conducted. eg. Glycine (Amino Acid) and GABA (Gamma Amino Butyric Acid) The nervous system consist of three parts – (i) Central Nervous System (CNS) – Brain and Spinal Cord (ii) Peripheral Nervous System (PNS) – Cranial nerves and Spinal nerves. (iii) Autonomous Nervous System (ANS) – Sympathetic Nervous System (SNS) and ParaSympathetic Nervous System (PSNS) • Autonomous nervous system is also known as ‘Vegetative nervous system’ or ‘Visceral nervous system’. •

Some include cranial nerves, spinal nerves, SNS and PSNS in one, the Peripheral Nervous System.

1. CENTRAL NERVOUS SYSTEM (CNS) Brain 

In all vertebrates the brain is enclosed in a brain box called cranium.



The brain is covered by two coatings (in frog) or three coatings (in mammals). These coating are called meninges (sing sing - meninx). In mammals the outer meninx, close to cranium, is of dense fibrous connective tissue, and is called Duramater.



The middle coating is called Arachnoid, and is made-up of delicate serous membrane. It is absent in frog’s brain.



The inner most membrane, close to brain, is of fine connective tissue and is called Piamater. This membrane consist of many blood vessels which provide nourishment to the brain.



Human brain weighs ~ 1.5 kg. (~ 2% of body weight )



The brain cavities are filled with a lymph like fluid called cerebro spinal fluid (CSF). It is secreted by choroid plexuses in the brain and flows to, subarachnoid space and subdural space through Foramen of Magendie (Dorsal) and Foramina of Luschka (Lateral) of medulla oblongata. The CSF provides nourishment to the brain and helps in the removal of metabolic waste. It also acts as a shock-absorber for protecting brain and spinal cord. A typical vertebrate brain consist of three parts(i) Fore brain (Prosencephalon) – Telencephalon (Cerebrum and olfactory lobes) and Diencephalon (ii) Mid brain ( Mesencephalon ) – Optic lobes

779 Check Point Differentiate between: (i) Nerve cord of chordates and nonchordates (ii) Synaptic fatigue and synaptic delay (iii) Resting potential and action potential (iv) Electrical synapses and chemical synapses (v) Excitatory and Inhibitory neurotransmitter (vi) Depolarization and repolarization (vii) Stimulus and impulse (viii) Pre-synaptic membrane and postsynaptic membrane (ix) Medullated and non- medullated nerve fibres

780

BIOLOGY (iii) Hind brain (Rhombencephalon) – Metencephalon (Cerebellum) and Myelencephalon (Medulla Oblongata) The longitudinal section of frog’s brain gives a clear understanding of the brain cavities and their relationship to each other. Similar cavities are present in human brain. Rhinocoel Left paracoel (II ventricle)

Right paracoel (I ventricle)

FORE BRAIN Foramen of Monro Diocoel (III ventricle) MID BRAIN

Optocoel Iter (Aqueduct of Sylvius) Metacoel (IV ventricle)

HIND BRAIN

Fig. 21.4 L. S. of Frog’s brain (Diagrammatic)



The cavity of right cerebral hemisphere is called Rt. Paracoel or 1st ventricle.



The left paracoel is known as 2nd ventricle.



The cavity of diencephalon is called diocoel or the 3rd ventricle.



The two paracoel (1st and 2nd ventricles) are connected to diocoel (3rd ventricle) through a passage called Foramen of Monro.



The cavity of mid brain is called Iter or Aqueduct of Sylvius and is present between diocoel and metacoel. (The cavity of optic lobes is called Optocoel. In mammals the optic lobes are solid and optocoel is absent) The cavity of hind brain is called Metacoel or 4th ventricle. Thus there are 4-ventricles in Frog’s and human’s brain. Each ventricle has inner lining of Ependymal epithelium. (The number of ventricles in the heart of Frog and human is only 1 and 2 respectively.)



HUMAN BRAIN There are three prominent and visible parts in human brain – (i) Cerebrum; (ii) Brain stem - Mid brain, Pons and Medulla Oblongata; (iii) Cerebellum

Cerebrum •

It consists of two cerebral hemispheres.

• (i) (ii) (iii) (iv)

Each hemisphere is differentiated into 4-lobes. Frontal lobe (FL) – Present towards forehead. Parietal lobe (PL) – Towards middle. Temporal lobe (TL) – Close to ear. Occipital lobe (OL) – In posterior most region.

NEURAL CONTROL & COORDINATION (PART-I & II)



781

These lobes have been named after the name of cranial bones. The boundaries of these lobes are marked by deep fissures or sulci (sing.-sulcus). There are gyri (ridges) and sulci (grooves) in each lobe of cerebrum to increase the surface area for accommodating more neurons.

Frontal lobe

Olfactory bulb

Primary Central sulcus Primary motor somatosensory cortex cortex Parietal lobe

Occipital lobe Temporal lobe

Cerebellum Spinal cord

Fig. 21.5

Human Brain



The outer ~ 2 to 4 mm thick portion of cerebrum consists of gray matter, and is called neocortex in mammals and cortex in Frog.



In sub cortical part of cerebrum there are groups of cytons and axons called nuclei and tracts respectively.



The two cerebral hemispheres are internally connected by a transverse band of myelinated nerve fibers, called Corpus Callosum. This band is present in the brain of all eutherian mammals including human. The anterior part of this band is called Genu and posterior Splenium.



Inside the cerebrum there are other nerve tracts also, like ‘association fibres’ and ‘projection fibres’. The internal capsule is an example of projection fibres.



There are two important nuclei or ganglia in fore brain. (i) Basal ganglia (ii) Limbic system

Basal ganglia •

They consist of two main structures, the corpus striatum (the biggest nucleus of basal ganglia) and red nucleus

•

Corpus striatum is further differentiated into Lenticular nucleus and Caudate nucleus.

•

The Lenticular nucleus contains 2-parts, the pallidum and putaman.

•

The caudate nucleus is differentiated into head and tail, and regulates motor activities. It also initiates locomotion.

Limbic System •

It is a fork like neural link between cerebrum and brain stem.

•

The term ‘Limbic system’ is preferred over Rhinencephalon (nose brain) as the latter is now an obsolete term.

•

The Limbic system includes limbic lobes, hippocampal lobe, a part of thalamus, hypothalamus and Amygdala.

782

BIOLOGY •

The Amygdala lobe is an almond shaped structure at the end of the tail of caudate nucleus. It controls the mood especially anger and emotional behaviour like fear and aggression.

•

The hippocampal lobe converts short term memory into long term memory. It also deals with olfaction (smell) Caudate Nucleus Head of caudate Nucleus

Limbic lobe PL

FL

Thalamus Post. column of Fornix

Pl OL

Pt

Lenticulate Nucleus

Tail of caudate Nucleus

TL Amygdala (Nucleus)

Hippocampus Parahippocampus Basal ganglia and Limbic system of human brain (Pl = Pallidum; Pt = Putaman) Premotor area Prefrontal area Lateral sulcus

Central sulcus

Motor area

FRO NT LOB AL E

Parieto-occipital sulcus

Broca's area Auditory area

TEMPORAL LOBE

OC C LO IPIT BE A L

PARIETAL LOBE

Wernicke's area Fig. 21.6 Limbic System

Connecting Concepts

Functions of Cerebrum (I) The Frontal lobe mainly contains prefrontal area, premotor area and motor area. • Broca’s centre is the motor centre for speech. It is dominant in left hemisphere of right handed persons and vice versa. It initiates the movement of lips, tongue and Larynx to produce speech.

 In Myasthenia gravis the muscle degeneration starts after the age of 30 years. Besides blockage of muscle receptors, there also develops deficiency of GABA in caudate nucleus. (II)

•

Frontal lobe is the centre of knowledge, wisdom, reasoning, judgement, logic, intelligence, creations, ideas and dreams. It also indicates persons’ will power, personality etc. The Parietal lobe has somato-sensory areas • Broadman’s area for speech is the sensory area, present in this lobe.

 Parkinson’s disease (shaking • It is also the centre for perception of pain, pressure, taste, touch and temperature. palsy) develops due to deficiency of a neurotransmitter (Dopamine) in a part (III) The Temporal lobe has olfactory area for smell and auditory area for hearing. It also has of basal ganglia. (Also see disorders of Wernicke’s area for understanding of speech. Nervous system, at the end of chapter). (IV) The occipital lobe is the area for vision and visual interpretations.

Functions of Hypothalamus (The dorsal wall of thalamus/diencephalon, i.e. roof of diocoel, is called Epithalamus, the ventral wall, i.e. floor of diocoel, is called Hypothalamus, and the lateral walls are called Optic thalami)

NEURAL CONTROL & COORDINATION (PART-I & II)

783

The hypothalamus of a typical brain has following important functions : (i) Osmoregulation (ii) Prespiration (iii) Thermoregulation (iv) Urge for Hunger (v) Urge for Thirst (vi) Pleasure (vii) Love and hate (viii) Sexual behaviour (ix) Satisfaction (Satiety centre) (x) Carbohydrate metabolism etc. (xi) Sleep It is the highest centre of autonomous nervous system (SNS and PSNS). It also governs the secretions of anterior pituitary through releasing hormones. The thalamus is the ‘relay centre of the body’ and selects the informations to be sent to cerebrum.

Mid Brain   

In human, like other mammals, there are 4-optic lobes (solid, without optocoel) and the condition is called Corpora Quadrigemina. The two anterior lobes, called Superior Colliculi, perceive stimulation of head and eyes - movements (visual reflex). Two posterior lobes, called Inferior Colliculi, perceive the stimulation of the movements of head and ear (auditory reflex).

Connecting Concepts  In frog’s brain the optic lobes are two and hollow. This conditions is called Corpora Bigemina. The cavity of optic lobes is called optocoel.

Hind Brain Cerebellum • • • • • • •

Like cerebrum the cerebellum also contains gyri and sulci. It is differentiated into three areas namely – (i) Superior Peduncle (ii) Median peduncle (iii) Inferior Peduncle Superior Peduncle connects cerebellum to mid brain. The Median peduncle contains Purkinje cells and connects cerebellum to Pons. (The Purkinje cells contain thousands of dendrites ) The Inferior peduncle connects the cerebellum to medulla oblongata. It has grey matter on the surface and the branched white matter (Arbor vitae) in the deeper parts. It coordinates the faster muscular movements and maintains the speed of locomotion. As it maintains the balance of the body (unconscious activity), it is also called ‘Gyroscope of the body’.

Pons •

The Pons Varolii, present in mammals only, controls breathing. It has pneumotaxic centre which is ‘switch on/off point’ for breathing.

Medulla oblongata • •

•

Check Point Mention precise location followings in human brain: (1) Broca’s centre (2) Corpus callosum (3) Amygdala lobe (4) III ventricle (5) Aqueduct of Sylvius (6) Thalamus (7) Limbic lobe (8) Pons (9) Pia mater (10) Hippocampal lobe (11) Occipital lobe (12) Optic lobe (13) Foramen of Monro (14) Medulla oblongata

the

It controls the following involuntary activities. a) Breathing b) Heart beat c) Vasomotor activity d) Peristalsis Medulla oblongata has Dorsal and ventral groups of neurons for regulating normal and faster breathing respectively. The accelerator and depressor centres of medulla regulate heart beat. The vasomotor centre controls blood pressure. Connecting Concepts Medulla oblongata also controls reflexes like coughing, sneezing, vomiting and  If medulla oblongata is destroyed hiccupping etc. the involuntary functions like heart (Medulla oblongata, unlike other parts of brain, has outer white matter and inner grey beat, breathing etc. will stop, resulting matter.) in death.

PERIPHERAL NERVOUS SYSTEM (PNS) 

of

It includes cranial and spinal nerves.

784

BIOLOGY

Cranial Nerves The nature of cranial nerves can be sensory, motor or mixed. Sensory nerves carry impulses from sensory organ or receptors to CNS. The axons of such neurons face CNS. Motor nerves carry impulses from CNS to the effectors organ. The axons of such neurons face the effectors organs. (e.g. Muscles / glands) The mixed nerves can carry impulses to and from CNS to the effectors organ. The axons of few neurons, in such nerves, face CNS, and axons of other neurons face effector organs. Cranial nerves arise from brain (not from cranium). The number of cranial nerves in fishes and amphibians is 10 pairs. In reptiles, birds and mammals (group Amniota) the number of cranial nerves is 12 pairs.

       

The largest (thickest) cranial nerve is 5th (trigeminal). This nerve is also known as Dentist’s nerve.



The longest and shortest cranial nerves in human are 10th (Vagus) and 4th (Trochlear) respectively. S. No.

Name of Cranial Nerve OLFACTORY

1st 2nd

OPTIC

3rd

OCCULOMOTOR

Origin

Nature

Fore brain

Sensory

(FB)

(S)

Distribution / Function Nasal epithelium – Smell

F.B.

S

Mid Brain

Motor

Retina – Vision *Extra ocular muscles of eye ball

(MB)

(M)

( 3-rectus and 1-oblique muscle) –

TROCHLEAR (PATHETIC)

M.B.

M

5th

TRIGEMINAL

Pons

Mixed

(Hind Brain)

(Mx)

al

ht

tp s:

//n ee

tm

ed ic

8th

9th

AUDITORY

GLOSSOPHARYNGEAL

.c

ot

sp og bl

FACIAL

Pons

M

Pons

Mx

y.

7th

m

ABDUCENS

Extra ocular muscles of eye ball (Superior oblique) – movement of eye ball 3 Branches –

(i)

Ophthalmic (S) - Eye lids, Conjunctiva and forehead

(ii)

Maxillary (S) – Upper Jaw, Gums, Lips and Cheek.

(iii)

Mandibularies (Mx) – Lower Jaw – Mastication (mainly) Extra ocular muscle of eye ball (External rectus) – movement of eye ball

ac ad e

6th

om

movement of eye ball

4th

(i)

Sensory part – From 2/3 of ant. tongue (taste buds)

(ii)

Motor part – movement of facial muscles for expression. In Rabbit 3-branches – Palatine, Hyomandibular and Chorda-tympani. (Chorda-tympani is absent in frog)

Pons

Medulla Oblongata (M.O.)

S

Mx

2-Branches (i)

Vestibular Nerve – Balancing the body

(ii)

Cochlear Nerve – Hearing

(i)

Sensory part – 1/3 (Posterior) of tongue – Taste buds

(ii)

Motor part – Movement of pharynx and saliva secretion (Parotid glands).

NEURAL CONTROL & COORDINATION (PART-I & II) 10th

VAGUS (PNEUMOGASTRIC)

M.O.

Mx

785

In fishes 3 branches – (i)

Lateralis – Lateral line organ

(ii)

Visceralis – Visceral organs

(iii)

Branchialis – Gills In mammals it is distributed in Lungs, Larynx, Oesophagus, Heart, Stomach, Kidney and Intestine through Laryngeal and depressor nerves mainly.

11th

SPINAL ACCESSORY

M.O.

M

Neck and Shoulder muscles – Movement

12th

HYPOGLOSSAL

M.O.

M

Tongue muscles – Movement.

* There are 6-extra ocular muscles in each eye ball, 4-rectus (superior and inferior rectus, external and internal rectus) and 2-obliques (superior and inferior obliques). CRANIAL NERVES IN FROG Sensory – 1st, 2nd, 8th Motor – 3rd, 4th, 6th Mixed – 5th ,7th, 9th, 10th Maximum cranial nerves ( 4 pairs ) are mixed in nature.

CRANIAL NERVES IN MAMMALS Sensory – 1st, 2nd, 8th Motor – 3rd, 4th, 6th 11th, 12th Mixed – 5th ,7th, 9th, 10th Maximum cranial nerves ( 5 pairs) are motor in nature.

Ganglia on the way of Cranial Nerves FROG

MAMMAL th

5

6th 7th th

8

th

9

th

10

Fig. 21.7 Cranial Nerves

Spinal Cord 

In human it is 40 to 50cm in length and ~2cm in diameter.



It lies inside neural canal of vertebrum column.



It terminates into Ist lumber vertebrum of abdominal region.



Non-nervous part of spinal cord (containing meninges) is called Filum terminale.



The bundle of spinal nerves in the posterior most part of the spinal cord is like a horse-tail, and is called Cauda equina.



Its development is completed upto the age of 5 or 6 years.



The spinal cord is Hollow or tubular and has neurocoel or central canal. This canal contains cerebro spinal fluid (CSF).



Outer region of spinal cord contains white matter whereas inner region contains grey matter. The white matter consists of medullated fibres (white), and grey matter has non-medullated fibres, mainly their cell bodies or cytons.



Gray matter in mammals is generally butterfly shaped and forms dorsal (posterior) and ventral (anterior) horns. In thoracic region the lateral horns are also differentiated.

786

BIOLOGY

Neurocoel Spinal cord Pia mater

Filum Terminale Sacrum

Coccyx Fig. 21.8 L. S. spinal cord



The white matter forms dorsal, ventral and lateral Funiculus containing ascending and descending tracts of white (medullated) fibres



The meninges present around brain also continue in spinal cord. The sub-arachnoid space too contains CSF.

Central canal or Neurocoel

Dorsal septum

Meninges

Dorsal or Dorsal posterior funiculus Interroot neuron Dorsal root ganglion Cyton

Dorsal horn of Gray matter

Sensory/Afferent neuron

Lateral funiculus

Spinal nerve

Lateral Horn Ventral horn of Gray matter Ventral fissure

Ventral funiculus

Ventral or anterior root

Motor / Efferent neuron

Ramus communicans

Fig. 21.9 T. S. Spinal cord showing Doral & Ventral roots of Spinal nerve

Spinal Nerves 

All spinal nerves are mixed in nature

Each nerves is formed by the union of 2-roots. (i) Dorsal (Posterior) root - It is sensory root and consists of sensory (Afferent) fibres. It also contains ‘dorsal root ganglion’ of pseudounipolar neurons. (ii) Ventral (anterior) root – It is motor root and consists of motor (Efferent) fibres. The smallest branch of spinal nerve is Ramus communicans. The preganglionic fibers of SNS pass through this branch. Number of spinal nerves – 1. Frog ( other than Rana tigrina ) – 10 pairs. 2. Rana tigrina – 9 pairs. 3. Human – 31 pairs. 4. Rabbit - 37 pairs 

NEURAL CONTROL & COORDINATION (PART-I & II)

787

Spinal Nerves in Human

Check Point

Region

Name of Nerves Cervical Nerves Thoracic Nerves Lumber Nerves Sacral Nerves Caudal Nerves

NECK CHEST ABDOMEN HIP TAIL

Number of Nerves 8-pairs 12-pairs 5-pairs 5-pairs 1-pair



1st Spinal nerve is called Hypoglossal nerve (the name of last cranial nerve is also the same)



The last spinal nerve (caudal) is called Coccygeal nerve

REFLEX ACTION  It is an involuntary and automatic response to a stimulus. Reflex arc – It is the path way of reflex action. Components of reflex arc – 1. Sensory structure (receptor organ) - eg. Skin 2. Afferent (sensory) neuron 3. Interneuron (Association neuron) 4. Efferent (motor) neuron 5. Effector organ – eg. Muscle or gland. In monosynaptic reflexes the interneurons are absent and the minimum number of neurons participating in such reflexes is ‘two’ – eg. Knee Jerk reflex.

Fill in the gaps (i) The posterior, non-nervous part of the spinal cord is called ..................... (ii) Facial (cranial) nerve in human passes through ..................... ganglion. (iii) ......................is the largest or thickest cranial nerve. (iv) The number of spinal nerves in Rana tigrina is ..................... pairs. (v) ..................... is the name of last cranial nerve in human. (vi) The number of sensory cranial nerves in human is -------------(vii) Funiculus is the name for -------------------- matter of spinal cord. (viii) In human the number of spinal nerves in neck region is -----------pairs. (ix) The cranial nerves that are present in amniotes only are -------------pairs. (x) ---------------- is the smallest branch of spinal nerve.

Types of Reflexes 1. Simple or Unconditioned Reflexes  

These reflexes are regulated through spinal cord (CNS) and participation of brain is not essential

Connecting Concepts

 Simple reflexes can be displayed by If , by the process of pithing in frog, the brain is disconnected from the spinal cord, such a newly born child. This is also the basis reflexes do not disappear. of memorizing the differences between eg. Blinking reflex, Pupillary reflex, Withdrawl reflex, Knee jerk reflex simple and conditioned reflexes. A The increase in heart beat after hearing a louder sound is also a simple reflex. newly born child can sneeze, vomit and The reflexes like sneezing, coughing, vomiting and swallowing are also included in this blink.

category.

First synapse

Dorsal root ganglion Call body of sensory neuron

Association Neuron Skin Receptor Spinal cord

Sensory or afferent neuron

Second synapse

Motor or Efferent neuron Fig. 21.10 A reflex are

2. Conditioned Reflexes 

In these reflexes the participation of brain is essential.



These reflexes require prior learning or training.



The path way of these reflexes passes through cerebrum.

Effector (muscle)

788

BIOLOGY Connecting Concepts



 Salivation after tasting the food, is a  simple reflex but if the salivation occurs due to sound of cutlery, or vision, or smell; it is a conditioned reflex.

Such reflexes may disappear and reappear. Ivon Pavlov is known as the ‘Father of conditioned reflexes’. He discovered conditioned reflexes for food in dogs. eg. Typing, Swimming, Dancing, Knitting, Driving, Cycling etc.

AUTONOMOUS NERVOUS SYSTEM (ANS) 

This nervous system is also known as ‘Vegetative nervous system’ or ‘Visceral nervous system’.



All the nerves of this nervous system are purely motor in nature.



It includes sympathetic nervous system (SNS) and parasympathetic nervous system (PSNS).

Sympathetic Nervous System ( SNS ) 

It is catabolic in action.



It consists a pair of chain of sympathetic ganglia. Each chain is present on either side of vertebral column.



The number of ganglia in the chain is ~10 in frog, ~18 in rabbit and ~22 in human.



SNS contains two types of fibres – preganglionic fibres and postganglionic fibres.

(A) Preganglionic fibres 

These fibres arise from gray matter of CNS and terminate in the chain of sympathetic ganglia.



These fibres pass through the spinal nerves of thoracic and lumber region. This system (SNS) is, therefore, also called as Thoraco-lumber outflow/system.



The preganglionic fibres of SNS come out from the spinal nerves through Ramus communicans, the thinnest branch of spinal nerve.



These fibres are myelinated and, therefore, white.



They are shorter than postganglionic fibres, as the chain of sympathatic ganglia is closer to the spinal cord.

Chain of Sympathetic Ganglia

Spinal nerve Ramus communicous Pre ganglionic fibre

Spinal cord Ventral root

Post ganglionic fibre

Fig. 21.11 Pre and Post ganglionic fibres of SNS (Diagrammatically represented)

Connecting Concepts

(B) Postganglionic fibres

 Exception - The postganglionic  fibres of SNS which supply the sweat glands and the blood vessels of skeletal  muscles secrete acetylcholine (not nor-  adrenaline) at the terminal ends

These fibres are longer than pre-ganglionic fibres. They are non-myelinated or grey. They arise from the chain of sympathetic ganglia and reach upto visceral organs. At the terminal end they secrete Nor-Adrenaline. The SNS is, therefore, also known as Adrenergic nervous system.

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Para Sympathetic Nervous System (PSNS)

Check Point



It is anabolic in action and restores the body functions for comfort and relaxation.



There is no chain of parasympathetic ganglia. The ganglia are either present in visceral organs or close to such organs.



PSNS also contains two type of fibers – Preganglionic fibers and Postganglionic fibers.

(A) Preganglionic fibres 

They arise from CNS and pass either through cranial nerves or the spinal nerves of sacral region. The PSNS system is, therefore, also known as Craniosacral outflow/system. The cranial nerves through which PSNS fibres pass, include only 10th in frog but 3rd, 7th, 9th, and 10th in mammals. The fibres which innervate eyes pass through 3rd cranial nerve and those innervating heart, pass through 10th cranial nerve.



These fibres are myelinated or white.

Differentiate between: (i) Dorsal and ventral roots of spinal cord. (ii) Grey matter and white matter (iii) Simple reflex and conditioned reflex (iv) Preganglionic and postganglionic fibres of SNS. (v) Adrenergic and Cholinergic nerves. (vi) Thoraco-lumber out flow and cranio-sacral out flow (vii) The functions of adrenaline and acetylcholine (viii) White and gray fibres of SNS

(B) Postganglionic fibres 

These fibres are shorter than preganglionic fibres.



They are non-myelinated or grey.



Check Point

They secrete Acetylcholine at the terminal ends, so PSNS fibres are known as Cholinergic fibres and this system is also known as Cholinergic nervous system

Functions of SNS and PSNS – SNS

PSNS

1.

Peristalsis, salivation and the secretion 1. of Digestive juices (Gastric juice, Bile juice, Pancreatic juice and Intestinal juice) inhibited inhibited.

Peristalsis, Salivation and secretion of digestive juices stimulated stimulated.

2.

Digestion and Absorption delayed

Digestion and absorption faster

3.

Urinary bladder relaxes to inhibit micturition. 3.

Urinary bladder contracts causing urination or micturition.

4.

Bronchioles increases

rate 4.

Bronchioles constrict and breathing rate normal

5.

Coronary artery dialates, Heart beat increases. 5. Blood supply to Heart and skeletal Muscles increases, but decreases in digestive system.

Heart beat normal. Blood supply to Heart and skeletal muscles, and digestive system normal.

6.

There is contraction of spleen (blood bank) 6. for releasing more blood.

No such effect.

7.

Blood clotting time decreased.

No such effect.

8.

Pupil dialated (Mydriasis) in dim light due to 8. constriction of radial muscles.

Pupil constricted (Miosis) in bright light due to constriction of circular muscles.

9.

Sweat glands stimulated for more heat loss. 9. Contraction of arrector pili muscles produces ‘Goose flesh’.

There is no parasympathetic nerve supply to skin.

Stimulates ejaculation of sperms.

Stimulates erection vasodialation.

10.

dialate

and

breathing

2.

7.

10.

Connecting Concepts

of

penis

by

Disorders of the Nervous System (1)

Hydrocephalus : • The volume of CSF is abnormally high. •

(2)

The head may be enlarged.

• It developes due to malabsorption, or obstruction in the flow of CSF. Meningitis : • It is inflammation of meningis. •

Which of the followings are not the functions of SNS. (i) Contraction of urinary bladder. (ii) Peristalsis (iii) Salivation (iv) Pupil dialation (v) Sweating (vi) Ejaculation of semen (vii) Contraction of arrector pili (muscles) (viii) Contraction of spleen (ix) Glycogenolysis (x) Anabolic activity

It develops mainly because of bacterial infection (Meningococcus and Streptococcus bacteria)

 If vagus nerve is cut in frog the heart beat increases. It is because the PSNS fibres passing through this cranial nerve are cut and acetylcholine (which reduces heart beat) is not secreted.  If vagus is stimulated the heart beat decreases because of the more secretion of acetylcholine at SA node.

790

BIOLOGY • (3)

It produces fever, severe headache and stiffness in the neck. The CSF also becomes turbid. Parkinson’s disease (Paralysis agitans) : • It develops due to deficiency of neurotransmitter, Dopamine. The dopamine is not produced due to gradual destruction of specific neurons. •

It produces muscle tremors, so the disease is also called as ‘Shaking Palsy’.

There is lack of control and co-ordination of movements resulting in expressionless features and stooping posture which gradually produces physical disability. Multiple Sclerosis • It is due to demyelination of white matter in the brain and spinal cord. •

(4)

• (5)

It is an autoimmune disorder and the susceptibility can be genetic also.

• It can cause abnormal sensation, muscular weakness and lack of co-ordination. Huntington’s Chorea • It is a genetic disorder (dominant autosomal) which onsets after the age of 30 years. •

(6)

There develops a deficiency of neurotransmitter, GABA, which causes rapid, involuntary and uncoordinated ‘dancing’ movements. There is progressive dementia followed by death. Alzheimer’s disease : • It was previously thought to be a ‘prion’ disease, but now, it is known to be produced by the deposition of abnormal amyloid (Tau) protein in the brain resulting in the degeneration of neurons. •

About 5-10% of the people above 60 yrs. are affected by this disease.

•

It produces memory loss, dementia, confusion, (inability of judgement) and abnormal behaviour. The death results within 10 years from the first onset of the disease.

•

It is mimicked by severe depression due to damage in Cholinergic pathways in brain.

•

Due to involvement of 21st chromosome, it is common amongst ‘Down syndromes’. The genes known for the disease produce the proneness or susceptibility.

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Part-II : Neural Control & Coordination While going through the chapter pay special attention to the following – Terms and Definitions – 1. Otoconia 3. Membranous Labyrinth 5. Uvea 7. Fovea centralis 9. Bowman’s gland

2. 4. 6. 8.

Echolocation Algesi-receptors Johnston’s organs Helicotrema

Differences – 1. Aquous humour and vitrous humour 2. Photopic vision and Scotopic vision 3. Night blindness and colour blindness 4. Thermo receptors and Caloreceptors 5. Fenestra ovalis and Fenestra rotundus 6. Basilar membrane and Reissner membrane Disorders – 1. Presbiopia 4. Hypermetropia Structures – 1. Ciliary Body 4. Iris 7. Cochlea

2. 5.

Glaucoma Cataract

3. 6.

Strabismus Conjunctivitis

2. 5.

Tapetum lucidum Columela auris

3. 6.

Schlemm Canal Lateral line organ



The important sensory organs in human body are eye, ear, tongue, nasal epithelium and skin.



The sensory organs or receptors can be Extero- receptors or Intero- receptors.



The Extero-receptors are present on the surface of the body and perceive distant stimuli. They are also known as Telo- receptors – eg. Eye and ear.



Intero-receptors are present in the visceral organs.



The receptors which are present in ligaments, tendons and skeletal muscles of limbs and detect the change of position of the body are called Proprioceptors. These receptors are sensory for the detection of earthquake Stimulus Light Pressure Sound Taste Cold Gravitational force Pain

Receptor Photoreceptor Baroreceptor Auditory receptor Gustatoreceptor Fridgido-receptor Georeceptor Algesireceptor

Stimulus Temperature Smell Touch Water current Warm / Hot Electric Current Balance

Receptor Thermoreceptor Olfactory receptor Thigmo/tangorec. Rheoreceptor Caloreceptor Galvanoreceptor Statoreceptor

HUMAN EYE 

It is a Photoreceptor Organ (Photoreceptor part – retina).



It is Ecto-mesodermal in origin. (Purely ectodermal parts – Retina. Lens, Conjunctiva and Iris-muscles).

792

BIOLOGY 

The photoreceptor part i.e. Retina, in the eyes of vertebrates, develops from nervous epithelium (as an outgrowth from diencephalon). The retina in such cases is called ‘Inverted’.

In case of invertebrates’ eyes the retina develops from skin epithelium, and is not inverted. 3 coatings – 1. Scleroid/sclerotic coat – It is the outer most coating of eye ball and develops from mesoderm. 2. Choroid – It is middle and is also mesodermal in origin. 3. Retina - It is the Inner most and Ectodermal in origin. 

1. Scleroid 

It consists of white fibrous connective tissue, and therefore, looks white. The anterior one sixth part of the eye ball, visible externally, is transparent and is called cornea. The major part (5/6) of the eye ball is white.



Six extra ocular muscles (4-rectus and 2-oblique) are attached to sclerotic coat and help in the movement of eye ball.

2. Choroid (Uvea)

Connecting Concepts



It is pigmented and highly vascularised coating.



Unlike scleroid, it is incomplete in the anterior region, and forms ciliary bodies and Iris.



The pupil (an opening for light entry) is present in the centre of the Iris. The eye colour is the colour of Iris.

 Iris, comparable to the diaphragm of camera, regulates the amount of light reaching retina. The radial muscles are  regulated by SNS and circular muscles are regulated by PSNS.

Connecting Concepts  The Aquous humour is later reabsorbed through the Schlemm canal, a venous channel at the junction of Iris and cornea.. If this schlemm canal is some how blocked, the pressure of the acquous humour rises causing damage to retina. This disorder is called Glaucoma.



Iris has two types of muscles – (i) Circular muscles – The contraction of these muscles, in bright light, constrict the pupil (Miosis) and reduces the amount of light passing to the retina. (ii) Radial muscles - The contraction of these muscles, in dim light, dilates the pupil (Mydriasis) to increase the amount of light passing to the retina. (Ophthalmologists use ‘atropine’ to dialate the pupil). Ciliary body secretes Aquous humour which provides nourishment to the lens and cornea because they do not have the blood supply of their own. The 2-chambers which contain aquous humour are anterior (between Cornea and Iris) and posterior (between Iris and Lens) chambers.

sclera choroid retina

aqueous humour conjunctiva vitreous humour

cornea lens

fovea

pupil Check Point Mention the location and one function of each of the following structures: (1) Proprioceptors (2) Tapetum lucidum (3) Schlemm canal (4) Amacrine cells (5) Fovea centralis

iris

suspensory ligaments

optic nerve blind spot

ciliary body

muscle Fig. 21.12 V. S. of mammalian eye

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793

Lens 

The lens in human eye is Biconvex, Circular, Living, Multi-cellular and non-vascularised (no blood supply).



It is purely ectodermal in origin.



Position of the lens in human is fixed but the focal length is adjustable. This adjustment of focal length by thinning or thickening of the lens is called Accommodation power.



The ciliary muscles, arising from ciliary body, adjust the focal length of the lens and thus help in Accommodation.

 

Connecting Concepts

 In frog the lens is spherical and The focal length (f) of human eye lens is 1.5 cm, with refractive power of 66.7 Diopters its focal length is fixed. Therefore, to at rest. change focal length, the lens moves to and fro. The suspensory ligaments ( Zonnules of Zinn ) keep the lens suspended in the centre.

3. Retina Connecting Concepts



It is sensory coating of the eye.



In human - eye the retina is inverted (sensory cells lie opposite to the entry of light ).



From outer to inner, the retina has 4 prominent layers – layer is replaced by a shining layer (i) Pigmented epithelium (ii) Sensory layer (iii) Bipolar neurons-layer called Tapetum lucidum. This layer (iv) Ganglionic layer with Optic nerve fibres. contains cysteine and guanine - crystals The pigmented epithelium absorbs oblique (scattered) light rays to prevent internal to reflect the maximum available light to the sensory layer. The reflecting of reflection (on retina).

 

 In animals which have ‘glowing eyes’, like cattle, cats, the pigmented

Amacrine and horizontal cells are present in the inner and outer border of bipolar neurons light in the eyes of such animals make the eyes glow in the dark. respectively, and transfer the information laterally to sharpen the contrast. receptor neurons

direction of light Ganglionic cells (IV) (nerve fibre layer)

ganglion cell

bipolar neurone

A

A

A

Bipolar neurons layer (III)

Sensory layer (II) direction of impulses Pigmented Epithelium (I) rods

cones

pigmented (melanin) cells

Fig. 21.13 Histology of retina (H-Horizontal cell; A-Amacrine cell)



The sensory layer has two types of sensory cells – (i) Rods (ii) Cones



In each human eye the number of rods (~ 120 million) is 20 times of that of cones.



Connecting Concepts The yellow spot at the visual axis of retina is called Macula lutea. This contains only  In nocturnal, animals only rods are cones (rods absent). The sharpest vision occurs at the central concave point of the yellow present (cones absent) - eg. Owl spot, called Fovea centralis.



The point from where optic nerve arises is called blind spot. Both rods and cones are  In case of night blindness the rhodopsin is not synthesized due to the absent at this point and therefore, there is no vision.



The rods are sensitive for vision in dim light (for black & white vision). The night vision (i.e., vision in dim light) is also called ‘Scotopic vision’.



The pigment present in rods is Rhodopsin (visual purple)



The cones are sensitive for bright light (for colour vision). The colour vision is called ‘Photopic vision’.



The pigment present in cones is called Photopsin (visual violet).



According to Trichromatic theory of vision, the cones are of three types in human.

deficiency of vitamin-A (Retinol).

794

BIOLOGY

 Connecting Concepts



 In colour blindness, a sex linked disease, there is defect in red and green-sensitive cones and hence, these two colours can not be distinguished.

(i) Red – sensitive (pigment – Erythropsin) (ii) Green – sensitive (pigment – Chloropsin) (iii) Blue – sensitive (pigment – Cyanopsin) Human can see clearly in the visible spectrum [wave length ~ 3800Å (380nm) to ~7600 Å (760nm)], but the best vision is at 5050 Å (505nm-yellow light). Insects, bony fishes, birds and mammals (except domestic animals) have colour vision. Honey bees can see even through ultraviolet light. Sharks (Cartilaginous fishes) and amphibians do not have colour vision. Between retina and lens there is a jelly-like mucous connective tissue, called Vitrous humour. It is permanent refractive medium and maintains the shape of the eye ball. The image formed on retina of human eye is laterally inverted and reverse (upside down).

Glands Lacrimal glands (Tear glands) • These glands produce tears for cleaning eye ball. • They lie in upper eye lids (one in each eye). • The tear secretion keeps the eye ball moist. • Tears also contain germicidal enzymes. • Tear glands are modified sweat glands and are absent in aquatic mammals. (ii) Harderian Glands • They are present in amphibians, reptiles, birds and a few mammals like whale, rats etc. • They produce oily secretion for lubricating nictitating membrane. (iii) Meibomian (Tarsal) Glands – • Such glands are present in the inner side of upper eye lids • They produce oily secretion for lubrication. • Their secretion prevents the overflow of the tears on to the cheeks. • They are modified sebaceous glands. • The infection of these glands may produce ‘styes’. (iv) Glands of Zeis • These glands are present at the base of eye lashes. • They keep the eye lashes soft, supple and smooth. (i)

Check Point Fill in the blanks : (i) .............. is the pigmented layer in the eye. (ii) In human eye, .............. is comparable to the diaphragm of the camera. (iii) Lens and Cornea are nourished by .............. . (iv) Adjustment of focal length of eyelens is called .............. power. (v) Three basic layers of retina are .............. . (vi) .............. lens is used for correcting hypermetropia. (vii) .............. is used for testing colour blindness. (viii) Cylinderical lens is used for correcting .............. . (ix) Eye develops from .............. (germ layer/s). The sensory cells in blind spot are .............. . (xi) -------------- is an old age defect of eye due to weakening of Ciliary muscles. (xii) Short sightedness due to change in the shape of eye ball is called ................. . (xiii) Vision in dim light is known as ................. . (xiv) ---------------- is a jelly-like mucous connective tissue between Lens and retina. (xv) Modified sweat glands that produce tears are ................. .

Disorders of the EYE (i)

Myopia – Short sightedness • It is mainly a congenital disorder in which the eye ball is elliptical and the visual axis is increased. •

The image is formed before retina.

•

Biconcave (Diverging) lens is used for correcting this disorder.

I

Myopia

II

II

Hypermetropia

Fig. 21.14 (I-Image formation without lens, II-Image formation after using lens)

(ii)

Hypermetropia – Long sightedness • It is also a congenital disorder in which the visual axis is shortened. •

Biconvex (converging) lens is used for the correction of this disorder.

I

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795

(iii) Astigmatism • The surface of Cornea/lens or both becomes uneven and few parts of the visual field are not in proper focus. • Cylindrical lens is used for the correction of this disorder. Connecting Concepts (iv) Cataract  The visual acuity is determined by • The transparency of Cornea/lens or both, is reduced ((Lens becomes Cloudy or ‘Snellen Letter Chart’, viewed from a Opaque) distance of 6 m (20 ft.). If the distance

• (v)

For correction, either the Cornea is grafted, or intra-ocular lens (IOL) is surgically at which subject reads the chart is ‘x’, implanted. then visual acuity is shown as 6/x. The Glaucoma normal vision is 6/6. • Schlemm canal, which absorbs Aquous humour, is blocked.

The pressure of Aquous humour (fluid) increases. (The normal intraocular pressure is 10-20 mm of Hg.). This may cause damage to retina, and blindness. (vi) Presbiopia • It is an old age defect of eye. •

•

It develops due to weakening of Ciliary muscles, and the lens can not thicken properly for viewing nearby objects. It is case of poor accommodation.

• Biconvex lens is used for its correction. (vii) Nyctalopia (Night blindness) • It develops due to deficiency of vitamin-A (Retinol), in which Rhodopsin pigment is not synthesized. • The affected person is unable to see clearly in dim light (viii) Daltonism (Colour blindness) • It is a sex-linked (genetic) disorder. •

The affected person is unable to distinguish between red and green colours. (This colour blindness is tested by ‘Ishihara Chart’).

•

It is the most common sex-linked disorder.

Check Point Can you differentate between: (i) Retina of invertebrate and vertebrate-eyes. (ii) Glaucoma and Cataract. (iii) The role of circular muscles and radial muscles of Iris. (iv) Ciliary body and ciliary muscles. (v) The eye lens of Frog and Rabbit.

The anomaly of colour blindness can be, Anopia (all colour blindness), Protanopia (Red colour blindness), Deuteranopia (Green colour blindness) and Tritanopia (Blue colour blindness). (ix) Conjunctivitis (Eye-flu) • It is allergic, bacterial or viral infection of conjunctiva (a covering over eye ball), and of the inner side of eye lids. (x) Strabismus (Heterotropia) • It is commonly called ‘squint’. •

•

It is abnormal alignment (generally horizontal) of the two eyes.

HUMAN EAR •

It is a statoacoustic organ, i.e. for balancing as well as hearing.

• The primary function of the ear is balancing (eg. Fishes) Human ear has 3-parts – Connecting Concepts (i) External ear – Pinna + Auditory meatus  In frog, round widow (fenestra (ii) Middle ear – Tympanic cavity + ear ossicles rotundus) is absent and only (iii) Internal ear – Vestibular apparatus + cochlea. Fenestra ovalis is present. Between external and middle ear, an ear drum (Tympanum) is present. Similarly, between middle ear and internal ear there are two membrane-bound windows – Oval window (Fenestra ovalis) and Round window (Fenestra rotundus) Connecting Concepts  Pinna is lacking in Egg-laying mammals (Prototherians) and Pinna (Auricula), a characteristic of mammals, directs sound vibrations towards some eutherians (like whales and dolphins). auditory meatus. It is made up of elastic cartilage.

(i) External Ear •

796

BIOLOGY •

The auricular muscles (of pinna) are vestigial in human.

•

Ceruminous glands are present in the lining of auditory meatus and secrete ear wax (Cerumen). The ear wax is sticky and prevents the entry of dust particles to the tympanum. It also prevents fungal and bacterial infections.

(ii)

Middle Ear •

The cavity of middle ear is called tympanic cavity. It develops from pharyngeal outgrowth and is, therefore, endodermal in origin.

•

Eustachian tubes connect middle ear to pharynx and prevent the rupturing of tympanum during louder sound by equalizing the pressure on the back of the membrane. The Eustachian tubes open during yawning, swallowing and chewing.

The tympanic cavity contains 3-ear ossicles (smaller bones). From tympanum to oval window, the sequence of these bones is – (i) Malleus – Hammer shaped (ii) Incus – Anvil shaped (iii) Stapes – Stirrup shaped (This sequence of the bones can be memorized by the letters ‘MIS’. )

•

Auricle (pinna)

Temporal bone

Malleus

Semicircular (A part of vestibular apparatus) canals Auditory nerve

Cochlea

Helix

Stapes

Lobule

Connecting Concepts

Incus

Tympanic External membrane acoustic Pharyngotympanic (auditory) (auditory) tube meatus or Eustachian canal

(A part of vestibular apparatus)

Fig. 21.15 Mamalian Ear

 Between malleus and incus there is Hinge joint while between incus and stapes the joint is Ball and Socket type.

•

The ear ossicles not only conduct sound vibrations but also amplify them.

•

Stapes, the smallest bone of mammalian body, fits on to the oval window.

(iii)

Internal Ear



The oval window is the inlet for the sound vibrations. Because of the smaller size of oval window the pressure of sound is also amplified on this membrane by about 20 times of the pressure on tympanum.



The sensory part of internal ear is called Membranous Labyrinth. It is filled with Endolymph.



The Membranous Labyrinth is surrounded by Bony Labyrinth, formed by ‘Temporal bone’. Between Membranous Labyrinth and Bony Labyrinth the fluid is Perilymph.



The internal ear has two prominent parts –

1. Vestibular Apparatus •

It is sensory part for balancing the body. It is also well developed in fishes.

•

It consist of 3-semicircular canals, one Utriculus and one Sacculus.

•

Out of 3-semicircular canals (SCC), two are vertical and one horizontal.

•

Each SCC is surrounded by bony canal. The fluid in between bony and membranous canal, as mentioned earlier, is perilymph.

NEURAL CONTROL & COORDINATION (PART-I & II)

797

•

At one end of each canal there is an Ampulla The Ampulla has sensory hair cells which are bathed in endolymph. The processes/cilia of the hair cells are grouped into a bundle, called Cupula, which is embedded in a jelly like lump called Crista, forming acoustic ridge. The hair cells of ampullae/SCC are sensory for ‘Rotational acceleration’.

•

The function of SCC is balancing during ‘rotational acceleration’ for which the ultimate sensory part is ‘hair cells’. When a person moves to right hand side the cupula also moves to that side and hair cells get stimulated. The vestibular branch of 8th cranial nerve carries the impulses to the brain, for balancing. (‘Vertigo’ is the sensation of rotation in the absence of actual rotation)

•

Utriculus also has a group of ‘hair cells’ at its floor, called Macula Utriculus (MU) which is bathed in endolymph.

•

The hair cells of MU are surrounded by an Otolithic membrane in which calcium carbonate crystals (otoconia/otolith) are embedded.

•

The hair cells of MU are sensory for ‘linear horizontal acceleration’.

•

Sacculus too contains group of hair cells lying in the walls in semi-vertical position. This group of hair cells is known as Macula Sacculus (MS).

•

The hair cells of MS are also sensory for ‘linear acceleration’, but for vertical movement.

•

Here also, the hair cells are surrounded by an otolithic membrane with otoconia.

•

(The acceleration in any direction causes displacement of otoliths in opposite direction, distorting the hair cell-processes, and this generates impulse). semi-circular canal

Vestibular apparatus

ampulla crista (hair cells) vestibular canal utricle

macula

Reissner's membrane

median canal tectorial membrame

saccule

basilar membrane

cochlea

Endolymphatic duct

tympanic canal hair cells

Vestibular apparatus and cochlea (Membranous Labyrinth)

T. S. cochlea Perilymph SV Helicotrema SM

Endolymph ST Perilymph L.S. of Terminal part of Cochlea

Fig. 21.16 SV - Scala vestibuli; SM - Scala media; ST - Scala tympani

2. Cochlea •

It is sensory structure for hearing.

•

It is a coiled structure, having 2 ¾ coils in human.

•

The Cochlea, in cross section, shows 3-canals.

receptor neurones (to auditory nerve)

798

BIOLOGY

•

•

The group of sensory ‘hair cells’ for hearing are present in cochlear canal or scala media.

•

The membrane at the roof of scala media which separates scala vestibuli from scala media is called Reissner membrane. The membrane at the floor of scala media, which separates scala media from scala tympani, is called Basilar membrane.

•

The ‘hair cells’ are attached to basilar membrane and form ‘Organ of Corti’, the ultimate sensory part for hearing. These hair cells are supported by Dieter cells. The group of hair cells is covered by a secretory (non-cellular) membrane called Tectorial membrane, into which the processes of hair cells are embedded.

•

(Tectorial membrane helps in stimulating the hair of hair cells of organ of Corti for generating impulse).

•

The longitudinal section of cochlea shows that scala vestibuli and scala tympani, both having perilymph, are connected at the terminal end through a passage called Helicotrema.

•

The cochlear branch of 8th (auditory) cranial nerve carries impulses to the brain.

Check Point Fill in the gaps (1-5) with suitable words to complete the following statements: The sensory structure for hearing in cochlea is ..........(1)............ which is covered by a non-secretory covering, ..........(2)............, and is dipped in ........... (3)........... fluid. The sound vibrations enter into the internal ear through a membrane bound window, ........... (4)........... . The other window between middle and internal ear is called ........... (5)...........

(i) Vestibular canal (Scala Vestibuli) (ii) Cochlear (median) canal (Scala Media) (iii) Tympanic canal (Scala Tympani) Vestibular canal and Tympanic canal are filled with perilymph while cochlear canal is filled with Endolymph. The cochlea, therefore contains both perilymph and endolymph fluids. (The cochlear or median canal, filled with endolymph, is the actual part of membranous labyrinth.

Route of Sound Vibrations – Auditory Meatus → Tympanum → Ear Ossicles → Oval window → Scala Vestibuli via Helicotrema → Scala Tympani → Basilar Membrane (Organ of Corti) → Cochlear nerve → Brain. Rest of the vibrations, which move through the round window are dumped in the middle ear. • The audible range in human is 20-20,000 Hz.

Connecting Concepts  Both bats and dogs can hear ultrasonic sound. Dogs can not produce such sound so echolocation is absent in dogs. In bats, it is cry which produces ultrasonic sound.

•

Outer coil of cochlea is for highest audible frequency (10,000-20,000 Hz), middle coil for medium frequency (~5,000 Hz) and the inner most coil is for lowest frequency (~100Hz).

•

Newly born child can hear the sound of higher frequency (~35,000 – 40,000 Hz).

•

Dogs can hear the ultrasonic sound ( > 20,000 Hz).

•

The bats can produce and hear ultrasonic sound (~100,000 Hz). Bats, thus, see through sound (Echolocation). This vision is also known as Acoustic vision.

•

The intensity of the audible sound in human ranges from 0 to 120 dB. [The unit of intensity of sound is deciBel (dB) after the name of Grahm Bel.]

•

The intensity of three ranges of sound are as follows : Whispering = 10-20dB; Conversation = 40-80-dB; Jet Planes = 120 dB.

Frog’s ear 

Pinna and external auditory meatus (parts of external ear) are absent in frog and the ear starts from tympanum.



The ear ossicle is single – Columela auris. It is homologous to ‘Stapes’ of mammals.



The round window, i.e. Fenestra rotundus, is absent.



The bony labyrinth is formed by Prootic bone. (In human, it is formed by temporal bone).



Cochlea is absent, so ‘Organ of Corti’ is also absent. In place of Cochlea ‘Pars basilaris’ and ‘Lagena’ are present for hearing.

NEURAL CONTROL & COORDINATION (PART-I & II)

799

TONGUE 

The lining of tongue is stratified squamous epithelium.



Papillae containing taste buds are mainly concentrated on tongue. These papillae are in the form of projections and make the tongue-surface rough. In a typical mammal there are 4-types of papillae – 1. Filiform – They are pointed and do not have taste buds 2. Fungiform – They are umbrella shaped All have 3. Circumvallate (vallate) – These are circular and the largest ones. Taste buds 4. Foliate – They are leaf shaped

Vallate papillae Bitter

Fungiform papillae

Sour Taste tones Salty

Filiform papillae

Sweet Fig. 21.17 Tongue

 



In human only three type of papillae are present ((Foliate Foliate papillae absent absent). ). The Circumvallate are few in number and are arranged at the back of the tongue in an inverted ‘V’ shaped fashion. The taste buds for sweet and salt taste are present at the tip of the tongue, while for sour and bitter taste the taste buds are present on the lateral and posterior most side of the tongue respectively. (Inorganic and organic acids (H+) are sour in taste; Glycerol, Chloroform, Morellin (Protein) and salts of Lead and Beryllium are sweet; the Quinine, Nicotine, Caffeine, urea, Morphine and salts of Ca++ and Mg++ are bitter in taste.) Facial (7th) and Glossopharyngeal (9th) cranial nerves innervate the taste buds.

NOSE 

 

Check Point

The nasal or olfactory lining is called Schneiderian membrane and is sensory for smell. It has three types of cells. (1) Receptors cells (sensory cells) – They are derivatives of bipolar neurons and form olfactory hair or sensory cilia. (2) Supporting cells – They are columnar epithelial cells. (3) Glandular cells of Bowman’s gland – These cells secrete mucus The strength of smell depends upon the number of receptors stimulated. The dogs and dog-fish have keen sense of smell.

Axons Bowman's gland

Receptor Cells

Supporting Cell

Mucus Olfactory Hair (Sensory cilia)

Connecting Concepts  In frog there are only two types of papillae i.e. Filiforn and Fungiform. The taste buds are present only in the Fungiform papillae. These taste buds are also distributed in other parts of the buccal cavity.

Nasal Cavity Fig. 21.18 Olfactory epithelium

Fill in the blanks, each with a suitable word or statement: (i) .............. canal connects pharynx to the middle ear. (ii) Ear wax is secreted by .............. glands. (iii) The fluid filled in membranous labyrinth is .............. . (iv) .............. papillae do not have taste buds. (v) The audible range in human is .............. to .............. Htz. (vi) Sensory structures (receptors) for cold are-------------------. (vii) ------------ are the largest papillae on human tongue. (viii) Nasal glands that secrete mucus are --------------. (ix) ------------ is the balancing part of internal ear. (x) The passage connecting vestibular and tympanic canal is called ----------------.

800

BIOLOGY

OTHER SENSORY STRUCTURES (1)

Lateral line organ – • It is present in fishes and tadpole larva of frog. •

(2)

It contains Neuromast cells which are sensory for water vibrations.

• Such sensory structure are called Rheo-receptors. Jacobson’s Organ – • It occurs in snakes and lizards. •

It is olfactory structure (for smell) and is present near internal nostrils (Choane).

• (3)

It is also present in frogs, rabbits and humans as well, but is best developed in snakes and lizards. Johnston’s Organ – • It is present in Insects. •

It is auditory as well as proprioceptor organ.

• (4) Check Point Match the items of column A with that of column B : Column A 1.

(5)

• It is thermoreceptor organ and lies between eye and ear of this snake. Whiskers/Barbules – • They are present in Rats, Cats and Cat-fishes

(6)

• They are Thigmo or tango receptors, i.e. sensory for touch. Ampullae of Lorenzini • They are present in the snout region of cartilaginous fishes (eg. Dog fish).

Column B

Loreal Pit (Organ)

A.

Auditory receptor

2.

Meissner’s corpuscle

B.

Thigmoreceptor

3.

Johnston’s organ

C.

Thermoreceptor

4.

Paccinian corpuscle

D.

Algesireceptor

E.

Baroreceptor

F.

Proprioceptor

G.

Olfactory receptor

It is best developed in mosquitoes, in which it is present in second segment (the pedicel) of the antenna. Loreal Pit (Organ ) – • It is present in Pit-viper (snake).

(7)

• They are thermoreceptor. Skin – The important receptors in the skin are – (i) Meissner’s Corpuscles and Merkel’s discs – Sensory for touch (Thigmoreceptors) (ii) Krause’s end Bulbs – Sensory for cold ( Fridgidoreceptors ) (iii) Ruffini’s end Bulbs – Sensory for hot ( Caloreceptors ) (iv) Paccinian’s Corpuscles – Sensory for pressure (Baroreceptors) (v) Free nerve endings – Sensory for pain (Algesireceptors)

NEURAL CONTROL & COORDINATION (PART-I & II)

801

EXERCISE - 1 | NCERT BASED QUESTIONS 1.

2.

3.

4.

5.

6.

7.

8. 9.

The impulses from CNS to skeletal muscles are relayed through (1) SNS (2) Somatic neural system (3) PSNS (4) All of these During resting stage the axonal membrane is (1) Impermeable to both cations and anions (2) Permeable to anions and impermeable to cat ions (3) More permeable to K ions and nearly impermeable to Na ions (4) None of these Sodium – Postassium pump across membrance, actively transports (1) 2-Na ions outwards and 3 K ions into the cell (2) 3-Na ions outwards and 2 K ions into the cell (3) 2-K ions out wards and 3 Na ions into the cell (4) 3 K ions outwards and 2 Na ions into the cell The polarity of the membrance is reversed (1) During action potential (2) When there is nerve impulse at the site (3) And the membrane is said to be depolarized (4) All of these statements are correct Mark the correct statement (1) Electrical synapses are more common in our neural system than chemical synapses (2) The new potential in post synaptic neuron may be either excitatory or inhibitory (3) Hypothalamus is the major coordination centre for sensory and motor signaling (4) The tracts of nerve fibres that connect two cerebral hemispheres are called corpora bigemina The cerebral cortex is (1) The outer layer of cerebrum, called white matter (2) Inner layer of cerebrum, called white matter (3) The outer layer of cerebrum, called grey matter (4) Inner layer of cerebrum, called grey matter The brain- stem includes the parts of (1) Fore brain and mid brain (2) Mid brain and hind brain (3) Fore brain, mid brain and hind brain (4) Hind brain only The secretion of gastric juice is controlled by (1) Cerebellum (2) ANS (3) Cerebrum (4) Medulla Afferent neurons transmit impulses via dorsal nerve root to (1) Sensory organs (2) Effector organs (3) CNS (4) The statement is incorrect since afferent neurons pass via ventral nerve root

10.

11.

Mark the correct statement (1) Limbic system is involved in emotional expression (2) Cerebral aqueduct passes through mid brain (3) The menix in contact of brain tissue is pia mater (4) All of these Select the answer with correct matching of the structure, its location and function Structure (1) Eustachian tube

Location Anterior part of internal ear

(2) Cerebellum

Mid brain

(3) Hypothalamus Fore brain

(4) Blind spot

12.

13. 14.

15.

16.

Near the place where optic nerve leaves the eye

Function Equalizes air pressure on either sides of tympanic membrane Controls respiration and gastric secretions Controls body temperature, urge for eating and drinking Rods and cones are present but inactive here

Accommodation is due to contraction of (1) Rectus and oblique muscles (2) Iris muscles (3) Ciliary body (4) Ciliary muscles Which cells (layer) of retina faces the lens (1) Ganglion cells (2) Photoreceptor cells (3) Bipolar cells (4) Pigmented cells Twilight vision is also called (1) Scotopic vision and is the function of rods (2) Scotopic vision and is the function of cones (3) Photopic vision and is the function of rods (4) Photopic vision and is the function of cones The thinned-out portion of retina where only cones are densely packed is, called (1) Blind spot (2) Corpus luteum (3) Macula lutea (4) Fovea Mark the correct statement (1) The space between cornea and lens is filled with transparent gel (2) When all cones are stimulated equally a sensation of no light (dark) is produced (3) Rhodopsin is purplish red protein, hence called visual purple (4) The anterior transparent portion of choroid is called cornea

802 17.

18.

19.

20.

21.

BIOLOGY The cochlea of ear contains (1) Perilymph (2) Aqueous humour (3) Perilymph and endolymph (4) Only endolymph Mark the incorrect statement (1) The ear ossicle attached to tympanic membrane is Malleus (2) Opsin (of Rhodopsin) develops from vitamin A (3) The pressure on ear drum is equalized by Eustachian tube (4) Otolith organ consists of saccule and utricle At the base of cochlea, the canal that ends at the oval window is (1) Scala tympani (2) Scala media (3) Scala vestibuli (4) Auditory The stereo cilia of hair cells of organ of Corti are covered with a thick elastic membrane called (1) Reissner’s membrane (2) Basilar membrane (3) Tympanic membrane (4) None of these Macula of labyrinth is bathed in (1) Aqueous humour (2) Vitreous humour

22.

23.

24.

25.

(3) Perilymph (4) Endolymph Mark the appropriate word for the box in the follwoing statement. The ripples in basilar membrane press the hair cells against the to generate nerve impulse for auditory cortex (1) Macula (2) Otolith (3) Round window (4) None of these The region of vertebrate’s eye where the optic nerve passes out of the retina is called (1) Yellow spot (2) Optic chiasma (3) Fovea (4) Blind spot Mark the wrong statement (1) The most developed part of human brain is cerebrum (2) The pitch of sound in human ear is determined by the spot of cochlear coil stimulated (3) The part of CNS that acts as a master clock is amygdala (4) None of these The amount of light that falls on retina is regulated by (1) Lens (2) Cornea (3) Iris (4) Ciliary muscles

NEURAL CONTROL & COORDINATION (PART-I & II)

803

EXERCISE - 2 | Window to Competitive Exams 1.

2.

3.

4.

5.

6.

7.

8.

9.

10.

11.

Outermost covering of brain is [CPMT ‘81, ‘87; MAHE ‘95] (1) Piamater (2) Duramater (3) Choroid (4) Arachnoid Part of mammalian brain controlling muscular coordination is [MP ‘95] (1) Cerebrum (2) Corpus callosum (3) Medulla oblongata (4) Cerebellum Fourth ventricle of brain occurs in [CPMT ‘91; MP ‘95] (1) Olfactory lobe (2) Medulla oblongata (3) Cerebral hemisphere (4) Diencephalon Nervous band connecting the two cerebral hemispheres is [MP ‘95; RPMT ‘95; Orissa ‘95] (1) Corpus albicans (2) Corpus callosum (3) Corpus striatum (4) Corpus spongiosum Third, sixth and eleventh cranial nerves are [BHU ‘95] (1) Oculomotor, abducens and Accessory Spinal (2) Oculomotor, Trigeminal and Glossopharyngeal (3) Trochlear, Facial and Accessory Spinal (4) Trochlear, Abducens and Glossopharyingeal Voluntary muscular coordination is under control of (1) Cerebellum [CPMT ‘94; MP ‘95] (2) Medulla oblongata (3) Hypothalamus (4) Cerebral hemispheres In snakes, eye lids are: [EAMCET ‘95] (1) Immovable (2) Movable (3) absent (4) All of these Which of the following is devoid of blood supply? [BHU ‘89; RPMT ‘95] (1) Retina (2) Choroid (3) Cornea (4) Scleroid What is found in the periphery of spinal cord? [MP ‘96] (1) Gray matter (2) White matter (3) Notochord (4) Myelinated nerve The hollow interior of the cerebrum is called [PCS ‘96] (1) Third ventricle (2) Fourth ventricle (3) Lateral ventricles (4) Second ventricles A person feels no sensation when he puts his hand over flame the part of the brain which has damaged is [DPMT ‘96]

12.

13.

14.

15.

16.

17. 18.

19. 20.

21.

(1) Cerebellum (2) Medulla oblongata (3) Diencephalon (4) Hypothalamus If ophthalmic branch of trigeminal cuts, what will be the effect? [CPMT ‘96] (1) Frog dies (2) Blindness appears (3) Frog loses its capacity of sensing (4) None of these Indicate the correct match in the following [PCS ‘96] (1) II cranial nerve —Vagus (2) V cranial nerve — Heart (3) VIII cranial nerve —Lower jaw muscle (4) VI cranial nerve — External rectus muscle of eye The potential diference between outside and inside of a nerve before excitation is known as [MP ‘96] (1) Spike potential (2) Reaction potential (3) Action potential (4) Resting potential Seventh cranial nerve enters [RPMT ‘96] (1) Jugular ganglion (2) Geniculate ganglion (3) Gasserian ganglion (4) Femoral ganglion Parasympathetic nervous system is not involved in (1) Peristalsis [RPMT ‘96] (2) Secretion of saliva (3) Dilation of pupil (4) Excitation of reproductive organs Father of conditioned reflex is [CPMT ‘96] (1) Pavlov (2) Marshall-Hall (3) Huxley (4) Hodgkin & Huxley Midbrain contains [BHU ‘96] (1) Corpora quadrigemina (2) Diencephalon (3) Cerebrum (4) None of the above Endolymph has good quantity of [RPMT ‘96] (1) Na+ (2) Ca++ (3) Mg++ (4) Cl– Cornea transplantation is successful as cornea is [CBSE ‘96] (1) Easily available (2) Without blood supply (3) Easily preserved (4) Easily stiched Eye muscles are innervated by [MP ‘90; Punjab ‘97] (1) Oculomotor, abducens and vagus (2) Oculomotor, trochlear and abducens (3) Oculomotor, abducens and facial (4) Oculomotor, facial and vagus

804 22.

23.

24.

25.

26. 27.

28.

29. 30.

31.

32.

33.

BIOLOGY Absolute refractory period during nerve impulse conduction is the period of : [PCS ‘97] (1) repolarization (2) depolarization (3) both repolarization oand depolarization (4) neither repolarization nor depolarization Which one of the following is an acquired reflex? [CPMT ‘97] (1) Pavlov’s dog salivation (2) Peristalsis (3) Courtship behaviour (4) All of these Vasomotor centre is innervated by [CPMT ‘97] (1) Sympathetic only (2) Parasympathetic only (3) Both sympathetic and parasympathetic motor fibres (4) None Direction of nerve impulse is reversed in junction (1) Axo-axonic [AIIMS ‘97] (2) Axo-dendritic (3) Axo-dentritic-axonic (4) None of the above Rhabdome is found in eyes of [CPMT ‘97] (1) Insects (2) Annelids (3) Rabbit (4) Frog In the chemistry of vision in mammals, the photosensitive substance is called: [CBSE ‘97] (1) Sclerotin (2) Retinol (3) Melanin (4) Rhodopsin In human eye, the blind spot contains [AMU ‘89; JIPMER ‘97] (1) Rods (2) Cones (3) Both rods and cones (4) Neither rods nor cones The statocyst of prawn is a: [PCS ‘97] (1) Tangoreceptor (2) Chemoreceptor (3) Gravity receptor (4) Sound receptor Find out the right matching from the following pairs : [PCS ‘97] (1) Accommodation .................. pupil (2) Colour perception .................. cones (3) Night blindness .................. rods (4) Binocular vision .................. iris Ora serrata is: [BHU ‘97] (1) oral cavity of protochordates (2) anterior edge of sensory portion of the retina (3) Taste receptor (4) a part of utriculus of ear Glaucoma is due to [BHU ‘97] (1) Blocking of canal of Schlemm (2) Drying up of vitreous humour (3) Non synthesis of rhodopsin (4) Opacity of lens/cornea Which of the nerves functions more like a tract of brain than a nerve? [CPMT ‘98] (1) trigeminal (2) abducens (3) glossopharyngeal (4) vagus

34.

35. 36.

37.

38.

39.

40.

41. 42.

43.

44.

45.

46.

Which two extra cranial nerves are present in amniotes ? [RPMT ‘98] (1) Laryngeal and hypoglossal (2) Spinal accessory and hypoglossal (3) Hypoglossal and facial (4) Trigeminal and glossopharyngeal Heart is innervated by [MP ‘96; AFMC ‘98] (1) Trigeminal (2) Vagus (3) Facial (4) Oculomotor Part of brain responsible for hearing is [BHU ‘81; RPMT ‘98] (1) Cerebellum (2) Cerebrum (3) Medulla (4) Hypothalamus Anaesthetics reduce pain by blocking nerve conduction due to [CBSE ‘98] (1) Blocking neurotransmitter receptors (2) Blocking Na+ channels (3) Blocking K+ channels (4) All the above Which one is a inhibitory neuro-transmitter ? [CPMT ‘98] (1) GABA (2) Adrenaline (3) Epinephrine (4) Acetylcholine Sympathetic nerves in mammals arise from [AIIMS ‘98] (1) Sacral region of spinal cord (2) Cervical region of spinal cord (3) Thoracico-lumber region of spinal cord (4) Cranial nerves and sacral region of spinal cord Which of the following ions are required for nerve conduction ? [CPMT ‘98] (1) Ca++, Na+ and K+ (2) Ca++ and Mg++ (3) Mg++ and K+ (4) Na+ and K+ Arbor vitae is mainly composed of [AIIMS ‘98] (1) Grey matter (2) Neuroglial cells (3) White matter (4) All of these The flow of tears in women is stimulated by (1) CNS [HPMT ‘98] (2) Peripheral nervous system (3) Parasympathetic system (4) Sympathetic system In mammals, the organs of Corti is found in [DPMT ‘85, 2000; RPMT ‘98] (1) Scala vestibule (2) Scala tympani (3) Scala media (4) Middle ear Superposition image in cockroach is formed during [CPMT ‘98] (1) Dark light (2) Dim light (3) Bright light (4) None of these One of the papilla of tongue is not gustatory in function in man [KCET ‘98] (1) Vallate (2) Filiform (3) Foliate (4) Fungiform The visual unit of a compound eye of an insect is [BHU ‘98] (1) Ommatidium (2) Rods (3) Rhabdome (4) Cones

NEURAL CONTROL & COORDINATION (PART-I & II) 47.

48.

49.

50. 51.

52.

53.

54.

55.

56. 57.

58.

59. 60.

Which one of the pigment is not found in cones? [AMU ‘98] (1) Erythrolabe (2) Chlorolabe (3) Cynolabe (4) Melanophore If eyeball is shorter and lens is thin, then probable defect would be: [RPMT ‘98] (1) Astigmatism (2) Presbyopia (3) Short-sightedness (4) Long-sightedness The black pigment in the eye, which reduces the internal reflection, is located in: [AIIMS ‘98] (1) iris (2) sclerotic (3) choroid (4) cornea Cells of ‘Deiter’ occur in [AIIMS ‘98] (1) Retina (2) Organ of Corti (3) Utriculus (4) Sebaceous glands Pacinian corpuscles are [AIIMS ‘98] (1) Glands (2) Pain receptors (3) Naked tactile receptors (4) Encapsulated pressure receptors Which part of the human eye adjust the focal length of lens ? [RPMT ‘98] (1) Acquous humour (2) Ciliary body (3) Conjunctiva (4) Cornea Sympathetic nervous system is also called [CPMT ‘87 ; CBSE ‘95; DPMT ‘99] (1) Visceral (2) Thoraco-lumber (3) Cranio-sacral (4) Mesenteric The first spinal nerve of frog is known as [JIPMER ‘93; EAMCET ‘99] (1) sciatic (2) hypoglossal (3) brachial (4) glossopharyngeal Release of cathecholamines from adrenal medulla (human) is controlled by the action of: [JIPMER ‘99] (1) post-ganglionic sympathetic nerves (2) pre-ganglionic sympathetic nerves (3) pre-ganglionic parasympathetic nerves (4) post-ganglionic parasympathetic nerves The main function of cerebellum is [MP’99] (1) Vision (2) Hearing (3) Balancing (4) Memory Which of the following is an example of conditioned reflex? [AIIMS ‘99] (1) Hand took up when piercing with a needle (2) You knee to take up a stone then dog runs away (3) Eyes closed when any thing enter into it (4) In digestion food goes forward in alimentary canal In frog, the nerve that innervates the retractor bulbi muscles of eye [EAMCET ‘99] (1) pathetic (2) optic (3) oculomotor (4) abducens Which of the following is the largest nerve ? (1) Vagus (2) Olfactory [MP ‘99] (3) Trigeminal (4) Glossopharyngeal The cranial nerve supplied to diaphragm is : (1) Vagus (2) Phrenic [MP ‘99] (3) Trigeminal (4) Glosssoparyngeal

805 61.

62.

63. 64.

65. 66. 67.

68.

69.

70.

71.

72.

The photosensitive pigments viz., erytrolabe, chlorolabe and cyanolabe are sensitive to the colours respectively: [CPMT ‘99] (1) red, green and blue (2) blue, green and red (3) green, red and blue (4) blue, red and green Eardrum is also known as: [MP ‘99] (1) Tensor tympani (2) Tympanic membrance (3) Scala vestibuli (4) Scala tympani Supensory ligament is part of: [CBSE ‘99] (1) Tongue (2) Brain (3) Heart (4) Eye The anterior choroid plexus forms the roof of (1) optocoel [EAMCET 2000] (2) 4th ventricle (3) diocoel (4) olfactory ventricle Hypoglossal nerve controls movement of [JK 2000] (1) Tongue (2) Heart (3) Eye (4) Ear Which one occurs in mesencephalon ? [CPMT 2000] (1) Cerebellum (2) Inferior colliculus (3) Thalamus (4) Mammilary body Neurotransmitter between neuron and a muscle cell is [CPMT 2000] (1) Dopamine (2) Serotinin (3) Endorphin (4) Acetylcholine At resting stage nerve cell has [Punjab 2000] (1) Low K+ outside and high Na+ inside (2) High K+ inside and high Na+ outside (3) High K+ inside and low Na+ outside (4) High K+ outside and low Na+ inside Which is not connected with autonomic system [BVP 2000] (1) Memory & learning (2) Peristalsis (3) Digestion (4) Excretion Hunger and thirst are controlled by : (1) Medulla oblongata [Haryana 2000] (2) Hypothalamus (3) Cerebellum (4) Cerebrum In frog, fenestra ovalis is: [CPMT 2000] (1) the opening in the auditory capsule which separates the middle ear from the inner ear (2) the communication between the pharynx and the tympanic cavity (3) the external opening of the tympanic cavity which is covered by the tympanic membrance (4) the air filled cavity of the middle ear In human eyes, colour perception is done by: [PCS 2000] (1) rod cells only (2) cone cells only (3) both rod and cone cells (4) choroid layer cells

806 73.

74.

75.

76.

77.

78.

79.

80.

81.

82.

83.

84.

BIOLOGY In frog, the sclerotic layer of eye is formed from: [EAMCET 2000] (1) mesoderm (2) ectoderm (3) endoderm (4) corneous layer In man the speed of recognition of a particular taste with a protruded tongue compared to the tongue in situ is: [PCS 2000] (1) faster (2) slower (3) unchanged (4) initially faster then slower Preganglionic sympathetic fibres are [MAHE ‘01] (1) Adrenergic (2) Cholinergic (3) Synergic (4) Hypergonic The main cause of paralysis is [MP ‘01] (1) some defect in muscles (2) complete destruction of motor nerves (3) complete destruction of sensory nerves (4) none of the above Identify the correct statement? [AIIMS ‘01] (1) Optic is the shortest nerve (2) Olfactory nerves have mixed fibres (3) In anamniotes last nerve is vagus (4) In amniotes last nerve is spinal accessory In rabbit, optic lobes are small because the eye sight is controlled by [RPMT ‘01] (1) frontal lobe (2) occipital lobe (3) temporal lobe (4) parietal lobe A frog has its brain crushed. But when pinched on the leg, it draws away. It is an example of [AIIMS ‘01] (1) simple reflex (2) conditioned reflex (3) automated motor response (4) neurotransmitter induced response Depolarisation of nerve cell involves [Kerala ‘01] (1) Influx of K+ (2) Influx of Na+ (3) Influx of Ca2+ and C1(4) Efflux of Na+ Structure connected with vision is Rabbit is [BHU ‘01] (1) Corpus callosum (2) Corpora quadrigemina (3) Corpus albicans (4) Hippocampus Longest nerve of head region is [BVP ‘01] (1) Vagus (2) Trigeminal (3) Pathetic (4) Auditory Which of the following causes transmission of impulse across the synapse? [AMU ‘01] (1) Na+ (2) K+ (3) Ca2+ (4) Mg2+ If parasympathetic nerve of the rabbit is cut then hearbeat [RPMT ‘01] (1) increases (2) stops (3) decreases (4) unaffected

85.

86.

87.

88.

89.

90.

91.

92.

93.

94.

95.

Medulla oblongata encloses [Haryana ‘2000; UA ‘01] (1) Fourth ventricle (2) Third ventricle (3) Second ventricle (4) Optic lobes Which one of the following cranial nerve is not a motor nerve? [PCS ‘01] (1) II (2) III (3) IV (4) XII Only rods are present in the eyes of: [MP ‘01] (1) owl (2) pigeon (3) fowl (4) squirrel Eustachian tube connects: [CPMT ‘91; PCS ‘01; MP ‘01] (1) Pharynx to middle ear (2) Middle ear to external ear (3) Left ventricle to right ventricle (4) Left atrium to right atrium Proprioceptors are those which give the sense of : [MP ‘01] (1) taste (2) chemicals (3) temperature (4) changes in the internal environment of the body When we move from light to dark, we fail to see for some time but soon the visibility becomes normal. It is (1) Accomodation (2) Adaptation [CBSE ‘01] (3) Photoperiodism (4) Mutation Route of reflex arc is [Wardha ‘02] (1) Receptors, effectors, grey mater and motor fibres (2) Receptors, sensory fibres, grey mater, motor fibres and effectors (3) Sensory fibres, grey mater, motor-fibres, receptors and effectors (4) Effectors, grey mater, motor, sensory fibres and receptors A bipolar neuron has [KCET ‘02] (1) 2 dendrites and 1 axon (2) 2 axons and 1 dendrite (3) 1 dendrite and 1 axon (4) 2 axons and 2 dendrites During conduction of nerve impulse [MP ‘02] (1) Na+ moves into axoplasm (2) Na+ moves out of axoplasm (3) K+ moves into axoplasm (4) Ca++ moves into axoplasm Purely motor nerve is [CPMT ‘91, ‘02; MP ‘02] (1) Optic (2) Abducens (3) Ophthalmic (4) Palatinus Iter (Aqueduct of Sylvius) is found between [DPMT ‘82; CPMT ‘89; BHU ‘99; WARDHA ‘01; Vellore ‘02] (1) Third and fourth ventricles (2) Two lateral ventricles (3) Lateral ventricles and third ventricle (4) Rhinocoel and lateral ventricles

NEURAL CONTROL & COORDINATION (PART-I & II) 96.

97.

98.

99.

100.

101.

102.

103.

104.

105.

106. 107.

Foramen of Monro is an aperture between [CPMT ‘82; BHU ‘02] (1) Third and fourth ventricles (2) Rhinocoel and diacoel (3) Lateral and third ventricles (4) Diacoel and metacoel. Which of the following communicates to the central canal of the spinal cord? [JIPMER ‘02] (1) Fifth ventricle (2) Third ventricle (3) Fourth ventricle (4) Lateral ventricle Which is mismatched ? [RPMT ‘02] (1) Cerebrum - memory (2) Medulla oblongata – temperature regulation (3) Cerebellum - equilibrium (4) Olfactory lobes - smell Broca area controls [BHU ‘02] (1) Breathing (2) Movement of vocal cords (3) Movement of tongue (4) Both (2) and (3) Broca’s area in human brain controls [BHU ‘02] (1) breathing and hiccup (2) movement of tongue (3) movement of limbs (4) all of these Myopia can be corrected by the spectacle with: [Kerala ‘02] (1) biconcave lens (2) bifocal lens (3) biconvex lens (4) cylindrical lens Meissner’s corpuscles are located in: [CPMT ‘02] (1) Pancreas and secrete trypsinogen (2) skin and perceive gentle pressure (3) Adrenal and secrete epinephrine (4) Spleen and destroy worn out erythrocytes Which of the following cranial nerves receives information from Organ of Corti? [RPMT ‘02] (1) Vagus (2) Trigeminal (3) Auditory (4) Oculomotor In mammalian cochlea, the thin-walled sloping roof of the scala media is referred to as: [IAS ‘02] (1) organ of Corti (2) scala tympani (3) basilar membrance (4) Ressner’s membrance Bowman’s glands occur in [AMU ‘02] (1) Seminiferous tubules (2) Pleural membrane (3) Olfactory membrane (4) Nephrons Opacity of eye lens leads to [JIPMER ‘02] (1) Glaucoma (2) Cataract (3) Presbyopia (4) Astigamatism Human eye is sensitive to light of wavelength [JIPMER ‘02] (1) 80-280 nm (2) 280-380 nm (3) 380-760 nm (4) 760-880 nm

807 108. For sound (good) reflex actions we require intact : [BHU ‘03] (1) spinal cord (2) cerebellum (3) hypothalamus (4) medulla oblogngata 109. Which is activated in stress condition? [DPMT ‘03] (1) Somatic (2) Sympathetic (3) Parasympathetic (4) Whole ANS 110. A polarised neuron is said to be in [Vellore ‘03] (1) action potential (2) resting potential (3) conducting stimulus (4) none of these 111. Which part of the brain is involved in loss of control when a person drinks alcohol? [Kerala ‘03] (1) Thalamus (2) Cerebrum (3) Pons varolii (4) Cerebellum 112. In the serial wise arrangement of cranial nerves, after which nerve we get trochlear nerve? [MHCET ‘03] (1) optic (2) olfactory (3) oculomotor (4) trigeminal 113. The enzyme required for the conduction of nerve impulse across synapse is: [Punjab ‘03] (1) peroxidase (2) choline acetylase (3) ascorbic acid oxidase (4) succinic dehydrogenase 114. The autonomic nervous system has control over [Kerala ‘03] (1) reflex action (2) sense organs (3) internal organs (4) skeletal muscles 115. Cerebellum of brain is [JK ‘03] (1) concerned with the maintenance of posture/ equilibrium (2) responsible for olfactory functions (3) controls optic functions (4) both (1) and (3) 116. In which part of the brain corpora quadrigemina is located? [MHCET ‘03] (1) diencephalon (2) mesencephalon (3) prosencephalon (4) rhombencephalon 117. Thermoregulatory centre in the body of homeothermal animals and man is found in [DPMT ‘85; CPMT ‘86; AFMC ‘03] (1) Skin (2) Diencephalon (3) Hypothalamus (4) Pituitary 118. Which of the following cranial nerves of a human being is both sensory and motor? [BHU ‘01; Punjab ‘03] (1) Optic (2) Olfactory (3) Abducens (4) Trigeminal 119. Sequence of meninges from inner to outside is [KCET ‘03] (1) Duramater – Archnoid – Piamater (2) Duramater – Piamater – Arachnoid (3) Arachnoid – Duramater - Piamater (4) Piamater- Arachnoid - Duramater

808 120. Pons connects [KCET ‘03] (1) Brain with spinal cord (2) Cerebrum with cerebellum (3) Two-lobes of cerebellum (4) Two cerebral hemispheres 121. Cranial nerve showing maximum branching is (1) Trigeminal (2) Vagus [AFMC ‘03] (3) Optic (4) Facial 122. The transmission of impulse through neurons is a [MP ‘98; Wardha ‘03] (1) physical phenomenon (2) chemical phenomenon (3) electro-chemical phenomenon (4) gravitational phenomenon 123. Receptor cells for balance in human ear are located in: [Orissa ‘03] (1) utricle, saccule and semicircular canal (2) malleus, incus and stapes (3) organ of Corti (4) eustachian tube 124. ‘Ishihara charts’ are used by ophthalmologists to detect: [BHU ‘2003] (1) visual acuity (2) night blindness (3) colourblindness (4) microbial infection 125. In myopia or short sightedness [MP ‘89; MAHE ‘95; KCET ‘96; EAMCET ‘99; AIIMS ‘03] (1) Image is formed slightly in front of retina because eye ball is longer (2) Eye ball is normal but image is formed over blind spot (3) Eye ball is normal but images is formed slightly behind the retina due to faulty lens (4) Curvature of cornea becomes irregular 126. Anvil-shaped bone is: [St. Johns MC ‘03] (1) Malleus (2) Incus (3) Stapes (4) Columella auris 127. In the following abnormalities of the eye which one is serious condition that leads to blindness? [Kerala ‘03] (1) Myopia (2) Glaucoma (3) Presbyopia (4) Astigmatism 128. If an organism has more rods in retina of eye it will be: [DPMT ‘03] (1) active during day (2) Having colour vision (3) active during night (4) both (1) and (3) 129. The depression in the retina of one eye which lodges only the cones is called: [BHU ‘03] (1) blind spot (2) red nuclei (3) fovea centralis (4) fenestra rotunda 130. The lens and cornea is not having blood supply. So the nutrients are supplied by: [Kerala ‘03] (1) blind spot (2) aqueous humour (3) vitreous humour (4) Lymph vessels 131. A person is wearing spectacles with concave lenses for correcting vision. While not using the glasses, the image of a distant object in his case will be formed: [AIIMS ‘03] (1) on the blind spot (2) behind the retina (3) on the yellow spot (4) in front of the retina

BIOLOGY 132. In a similarity with photographic camera the retina acts as [AFMC ‘03] (1) Shutter (2) Lens (3) Diaphragm (4) Film 133. Which one of the following helps the eye to see near and far off objects by change in the focal length of the lens? (1) choroid [Jharkhand ‘03] (2) optic nerve (3) supensory ligaments (4) ciliary muscles 134. The size of aperture of the pupil of one eye is controlled by: [Vellore ‘03] (1) iris (2) retina (3) cornea (4) conjunctive 135. In the resting state of the neural membrane, diffusion due to concentration gradients, if allowed would drive : (1) K+ into the cell [CBSE ‘04] (2) Na+ into the cell (3) Na+ out of the cell (4) K+ and Na+ out of the cell 136. Injury to vagus nerve in humans in not likely to affect: [CBSE ‘04] (1) cardiac movements (2) tongue movements (3) pancreatic secretion (4) gastrointestinal movements 137. Respiratory centre is situated in [Punjab ‘99; CPMT ‘02; KCET ‘05] (1) Cerebellum (2) Medulla oblongata (3) Hypothalamus (4) Cerebrum 138. One of the examples of the action of the autonomous nervous system is [CBSE’05] (1) swallowing of food (2) pupillary reflex (3) peristalsis of the intestine (4) knee-jerk response 139. Parkinson’s disease (characterized by tremors and progressive rigidity of limbs) is caused by degeneration of brain neurons that are involved in movement control and make use of neurotransmitter [CBSE’05] (1) acetylcholine (2) norepinephrine (3) dopamine (4) GABA 140. In a man, abducens nerve is injured. Which one of the following functions will be affected? (1) Movement of the eye ball [CBSE’05] (2) Movement of the tongue (3) Swallowing (4) Movement of the neck 141. Which has H - shaped grey matter? [MAHE ‘05] (1) cerebrum (2) medulla oblongata (3) cerebellum (4) spinal cord

NEURAL CONTROL & COORDINATION (PART-I & II)

809

142. Find out the correct answer from the following statements. The main functions of the cerebrum of human brain are [Manipur ‘05] (a) to control the contraction of voluntary muscles through the frontal lobe (b) to control the sensitivity, movement, memory, vocabulary etc. through the frontal lobe (c) to control the temperature, taste, touch, pain etc. through the parietal lobe (d) to control the vision and adaptation through the occipital and frontal lobes (1) a.b. d (2) c, d, a (3) a, b, c (4) b, c, d 143. If after cutting through the dorsal root of a spinal nerve of a mammal, an associated receptor in the skin were stimulated, the animal would [CPMT ‘05] (1) still be able to feel the stimulation (2) show no response (3) show a normal but slow response (4) respond but only at a different level of spinal cord 144. Cranial nerves in frog are [CPMT ‘05] (1) 12 pairs (2) 9 pairs + 1 (3) 10 pairs + 1 (4) 10 pairs 145. Corpus callosum connects [MAHE ‘05] (1) two cerebral hemispheres (2) two ventricles of brain (3) two cerebellar hemispheres (4) two optic thalamus 146. You are watching a horror movie and you notice your heart is beating fast and mouth is dry. It is because of [Kerala’05] (1) fight and flight response (2) sympathetic nervous system (3) parasympathetic nervous system (4) both (1) and (2) 147. Arbor vitae is part of [MAHE ‘05] (1) cerebrum (2) cerebellum (3) mid brain (4) fore brain 148. Reflex action is controlled by [Kerala ‘05] (1) sympathetic nervous system (2) automatic nervous system (3) spinal cord (4) craniosacral outflow. 149. Tree of life is [BHU ‘05; AMU ‘05] (1) arbor vitae (2) pons varolii (3) origin of corti (4) diencephalon 150. Cranial nerves (in pairs) in frog and man are (1) 10 and 12 (2) 12 and 10 [MAHE ‘05] (3) 10 and 8 (4) 8 and 10 151. In parasympathetic nervous system which of the following is released ? [BHU ‘05] (1) epinephrine (2) nor epinephrine (3) serotonin (4) acetylcholine 152. Column I lists the parts of the human brain and colum II lists the functions. Match the two columns and identify the correct choice from those given. [KCET ‘05]

Column II p. controls the pituitary q. controls vision and hearing r. controls the rate of heart beat s. seat of intelligence t. maintains body posture (1) A = t; B = s; C = q; D = p (2) A = s; B = t; C = r; D = p (3) A = t; B = s; C = r; D = q (4) A = t; B = t; C = p; D = q 153. The following diagram indicates the reflex arc. Identify the parts labelled as A, B, C, D, E, F and G. Choose the correct option [KCET ‘05] C A A. B. C. D.

Column I Cerebrum Cerebellum Hypothalamus Midbrain

B

154.

155.

156.

157.

F E G D (1) A = sense organ; B = sensory nerve; C = dorsal horn; D = interneuron; E = ventral horn; F = motor nerve ; G = effector (2) A = sense organ; B = sensory nerve; C = ventral horn; D = interneuron; E = dorsal horn; F = motor nerve; G = effector (3) A = effector; B = motor nerve; C = dorsal horn; D = interneuron; E = ventral horn; F = sensory nerve; G = effector (4) A = effector; B = motor nerve; C = ventral horn; D = interneuron; E = dorsal horn; F = sensory nerve; G = sense organ. Which of the following reflex does not include innervations of brain ? [Orissa ‘05] (1) spinal reflex (2) cranial reflex (3) afferent reflex (4) efferent reflex. Delicious food is due to [JK ‘05] (1) olfactory response (2) hormonal response (3) neural response (4) optic response. Hypothalamus does not control [Kerala ‘05] (1) Hunger and satiety (2) thermoregulation (3) creative thinking and consciousness (4) osmoregulation. Match the following human spinal nerves in column I with the number of pairs in column II and choose the correct options [Kerala ‘05] Column I Column II A. cervical nerves 1. 5 pairs B. thoracic nerves 2. 1 pair C. lumbar nerves 3 12 pairs D. coccygeal nerves 4. 8 pairs

810

158.

159.

160.

161.

162. 163.

164.

165.

BIOLOGY (1) A - 2, B - 4, C - 1, D - 3 (2) A - 4, B - 3, C - 1, D - 2 (3) A - 3, B - 1, C - 2, D - 4 (4) A - 4, B - 1, C - 2, D - 3 The brachial plexus are formed by these spinal nerves : [EAMCET ‘05] (1) IV, V, VI cervical (2) V, VI, VII, VIII cervical and I thoracic (3) IV to VII Lumbar (4) First three sacral Human ear ossicles are [BHU ‘05] (1) incus and stapes (2) stapes (3) incus, malleus and stapes (4) incus and malleus ‘Adaptation’ of eyes in dark is due to [BHU ‘05] (1) depletion of vision pigment in rod (2) depletion of vision pigment in cones (3) repletion of vision pigment in rods Area of cerebral cortex controlling vision is [TN’01; Kerala’06] (1) Frontal lobe (2) Parietal lobe (3) Temporal lobe (4) Occipital lobe Brain ventricles are lined by [MP ‘97;CPMT’06 ] (1) Podocyte (2) Schwann cells (3) Neuroglia cells (4) Ependymal cells Which one of these is not a reflex reaction ? (1) Salivation [CPMT ‘87, ‘06] (2) Blinking of eyes due to strong light (3) Flexon due to needle prick (4) Secretion of sweat Which one of the following does not act as a neurotransmitter ? [CBSE ‘06] (1) Epinephrine (2) Norepinephrine (3) Cortisone (4) Acetylcoholine Given below is a table comparing the effects of sympathetic and parasympathetic nervous system for four features (1– 4). Which one feature is correctly described?[AIIMS’06]

Sympathetic Parasympathetic Feature nervous system nervous system 1. Salivary stimulates inhibits secretion glands secretion 2. Pupil of eye dilates constricts 3. Heart rate decreases increases 4. Intestinal stimulates inhibits secretion peristalsis secretion 166. Feelings of anger, pain and pleasure are experienced through [GCET’06] (1) limbic system (2) frontal lobe (3) parietal lobe (4) reticular system 167. How many pairs of spinal nerve are found in human? [GCET’06] (1) 32 (2) 31 (3) 30 (4) 33 168. In the given diagram which stage of conduction of nerve impulse through nerve fibre is observed? [GCET’06]

ECF Potassium channel

169.

170.

171.

172.

173.

174.

175.

176.

177.

178.

Na

ICF

Cl

K

Na

Na+ , K + pump

Cl

K K

K

Na

Na Protein K

Sodium channel K

(1) polarization (2) resting potential (3) repolarization (4) depolarization 5th cranial nerve of frog is called [BHU’06; CPMT ‘06] (1) optic nerve (2) vagus (3) trigeminal (4) opthalmic The function of cerebrospinal fluid does not include [HPMT’06] (1) protection of delicate brain and spinal cord from shock (2) protection of brain and spinal cord by containing antibody (3) buoyancy to brain (4) as a medium for excretion of waste product The hippocampus coverts information from [HPMT’06] (1) short term memory to long term memory (2) long term memory to short term memory (3) aggression to remembering fear (4) does not convert information In brain the region for perception of pain is located in [HPMT’06] (1) temporal lobe (2) parietal lobe (3) frontal lobe (4) occipital lobe In human brain the cerebral cortex contain roughly [HPMT’06] (1) 75% of all neuron of brain (2) 10% of all neuron of brain (3) 20% of all neuron of brain (4) 30% of all neuron of brain The mandibular nerve is the branch of which cranial nerve? [JK’06] (1) II (2) III (3) V (4) VI Facial nerve arising from medulla is [Orissa’06] (1) motor (2) sensory (3) sensory and motor (4) none of these Epinephrine and non-epinephrine act as both hormone and [CPMT’06] (1) neurotransmitter (2) carcinogens (3) enzyme (4) all of these Dilation of pupil of human eye is caused by the (1) parathormone [CPMT’06] (2) sympathetic nerve (3) parasympathetic nerve (4) PNS The accumulation of protein called amyloid β peptide in human brain causes [Kerala’06] (1) Addison’s disease (2) Huntington’s disease (3) Alzheimer’s disease (4) motor-neuron disease

NEURAL CONTROL & COORDINATION (PART-I & II)

811

179. A typical value of resting membrane potential is [Kerala’06; CPMT ‘06] (1) – 40m V (2) – 60m V (3) – 70m V (4) – 80m V 180. Match the entries in column I with those in column II and choose the correct combination from the options given. [Kerala’06]

188. Adaptation of colour vision is found is [Orissa ‘06] (1) mammals (2) aves (3) reptiles (4) all of these 189. The receptor absent in tongue is [BHU ‘06] (1) thermorecepor (2) gustatoreceptor (3) photoreceptor (4) none of these 190. During the transmission of nerve impulse through a nerve fibre , the potential on the inner side of the plasma membrane has which type of electric charge? [CBSE’07] (1) First positive, then negative and again back to positive (2) First negative, then positive and again back to negative (3) First positive, then negative and continue to be negative (4) First negative, then positive and continue to be positive 191. During the propagation of a nerve impulse, the action potential results from the movement of: [CBSE ‘08] (1) Na+ ions from extracellular fluid to intracellular fluid (2) K+ ions from extracellular fluid to intracellular fluid (3) Na+ ions from intracellular fluid to extracellular fluid (4) k+ ions from intracellular fluid to extracellular fluid 192. Which one of the following is the correct difference between rod cells and cone cells of our retina. [CBSE ‘08]

181.

182.

183.

184.

Column I Column II a. diencephalon 1. cerebellum b. telencephalon 2. medulla c. myelencephalon 3. amygdala d. metencephalon 4. thalamus (1) a–4, b–3, c–1, d–2 (2) a–3, b–4, c–1, d–2 (3) a–4, b–3, c–2, d–1 (4) a–1, b–2, c–3, d–4 Organs of Ruffini are receptors of [BHU ‘83, 2000; AMU ‘06] (1) Cold (2) Pressure (3) Heat (4) Touch Eustachian tube connects [CPMT ‘91’ Orissa ‘06] (1) External ear with middle ear (2) External ear with internal ear (3) Middle ear with pharynx (4) Internal pharyax (4) replection of vision pigment in cones Bowman’s glands are found in [CBSE ‘06] (1) external auditory canal (2) cortical nephrons only (3) juxtamedullary nephrons (4) olfactory epithelium Examine the diagram of the two cell types A and B given below and select the correct option [AIIMS ‘06]

Rod Cells (1) Distribution More concentrated in centre of retina (2) Visual High acuity (3) Visual Iodopsin pigment contained (4) Over all Vision in poor function light

Cone Cells Evenly distributed all over retina Low Rhodopsin

Colour vision and detailed vision in bright light 193. Given below is a diagrammatic cross section of a single loop of human cochlea: [CBSE ‘08 ] B A (1) cell A is the rod cell found evenly all over retina (2) cell A is the cone cell more concentrated in the fovea centralis (3) cell B is concerned with colour vision in bright light (4) cell A is sensitive to low light intensities 185. In which of following only cone cells are found? (1) fovea centralis (2) retina [GCET ‘06] (3) fossa ovalis (4) blind spot 186. The mucous in the nose is secreted in response to odouriferous substances by [HPMT ‘06] (1) lacrymal gland (2) olfactory gland (3) Bowman’s glands (4) salivary glands 187. Eye lenses focuss light on the retina containing rod cells, which are receptors. Number of rod cells in eyes is (1) 120 million (2) 105 million [Orissa ‘06] (3) 150 million (4) 118 million

B

A

C D

Which one of the following options correctly represents the name of three different parts? (1) A: Perilymph, B: Tectorial membrane C: Endolymph (2) B: Tectorial membrane, C:Perilymph, D: Secretory cells (3) C: Endolymph, D: Sensory hair cells, A: Serum (4) D: Sensory hair cells, A: Endolymph B: Tectorial membrane

812 194. Alzhimer disease in humans is associated with the deficiency of: [CBSE ‘09] (1) gamma aminobutyric acid (GABA) (2) dopamine (3) glutamic acid (4) acetylcholine 195. Which part of human hrain is concerned with the regulation of body temperature? [CBSE ‘09] (1) Hypothalamus (2) Medulla Oblongata (3) Cerebellum (4) Cerebrum 196. The nerve centres which control the body temperature and the urge for eating are contained in: [CBSE ‘10] (1) Thalamus (2) Hypothalamus (3) Pons (4) Cerebellum 197. Select the answer with correct matching of the structure, its location and function [CBSE Final’ 10] Structure (1) Eustachian tube

Location Function Anterior part Equalizes air pressure of internal ear on either sides of tympanic membrane (2) Cerebellum Mid brain Controls respiration and gastric secretions (3) Hypothalamus Fore brain Controls body temperature, urge for eating and drinking (4) Blind spot Near the Rods and cones are place where present but inactive optic nerve here leaves the eye 198. Colour perception in man is due to [DPMT’ 10] (1) Rhodopsin pigment in rod cells (2) Iodopsin pigment in cone cells (3) Iodopsin pigment in rod cells (4) Rhodopsin pigment in cone cells 199. When a neuron is in resting state i.e. not conducting any impulse, the axonal membrane is [CBSE’ 11] (1) Comparatively more permeable to K+ ions and nearly impermeable to Na+ ions (2) Comparatively more permeable to Na+ ions and nearly impermeable to K+ ions (3) Equally permeable to both Na+ and K+ ions (4) Impermeable to both Na+ and K+ ions 200. Vomiting centre is located in the [DPMT’ 11] (1) Medulla oblongata (2) Stomach and sometimes in duodenum (3) GI tract (4) Hypothalamus 201. The reflex arc, which is made of two neurones is known as [WB-JEE’ 11] (1) Monosynaptic reflex arc (2) Bisynaptic reflex arc (3) Polysynaptic reflex arc (4) Asynaptic reflex arc 202. Which of the following substances can cure Parkinson’s disease? [WB-JEE’ 11] (1) GABA (2) Acetylcholine (3) Dopamine (4) Glutamic acid

BIOLOGY 203. Which function will be lost due to damage of occipital lobe? [WB-JEE’ 11] (1) Hearing (2) Speech (3) Vision (4) Memory 204. The purplish red pigment rhodopsin contained in the rods type of photoreceptor cells of the human eye, is a derivative of [CBSE’ 11] (1) Vitamin A (2) Vitamin B1 (3) Vitamin C (4) Vitamin D 205. The human hind brain comprises three parts, one of which is [CBSE’ 12] (1) Cerebellum (2) Hypothalamus (3) Spinal cord (4) Corpus callosum 206. A person entering an empty room suddenly finds a snake right in front on opening the door. Which one of the following is likely to happen in his neuro-hormonal control system? [CBSE’ 12] (1) Hypothalamus activates the parasympathetic division of brain (2) Sympathetic nervous system is activated releasing epinephrin and norepinephrin from adrenal cortex (3) Sympathetic nervous system is activated releasing epinephrin and norepinephrin from adrenal medulla (4) Neurotransmitters diffuse rapidly across the cleft and transmit a nerve impulse 207. Which part of the human ear plays no role in hearing as such but is otherwise very much required? [CBSE’ 12] (1) Vestibular apparatus (2) Ear ossicles (3) Eustachian tube (4) Organ of Corti 208. The most abundant intracellular cation is [AIPMT (NEET)’13] ++ ++ (1) Na (2) Ca (3) H+ (4) K+ 209. A diagram showing axon terminal and synapse is given. Identify correctly at least two of A- D. [AIPMT (NEET)’13]

(1) (2) (3) (4)

A- Receptor, C- synaptic vesicle B- synaptic connection, D- K+ A- Neurotransmitter, B- synaptic cleft C- Neurotransmitter, D- Ca++

NEURAL CONTROL & COORDINATION (PART-I & II)

813

210. Parts A, B, C and D of the human eye are shown in the diagram. Select the option which gives the correct identification along with its functions/characteristics [AIPMT (NEET)’13]

217. Which of the following regions of the brain is incorrectly paired with its function? [AIPMT’15] (1) Medulla oblongata – homeostatic control (2) Cerebellum – language comprehension (3) Corpus callosum – communication between the left and right cerebral cortices (4) Cerebrum – calculation and contemplation 218. A gymnast is able to balance his body upside down even in the total darkness because of: [AIPMT’15] (1) Cochlea (2) Vestibular apparatus (3) Tectorial membrane (4) Organ of Corti 219. In mammalian eye, the ‘fovea’ is the center of the visual field, where: [RE-TEST AIPMT’15] (1) The optic nerve leaves the eye (2) Only rods are present (3) More rods than cones are found (4) High density of cones occur, but has no rods 220. Destruction of the anterior horn cells of the spinal cord would result in loss of: [RE-TEST AIPMT’15] (1) Voluntary motor impulses (2) Commissural impulses (3) Integrating impulses (4) Sensory impulses 221. Conduction of nerve impulse is a: [UP CPMT’15] (1) Chemical process (2) Physical process (3) Electrochemical process (4) Biochemical process 222. The ‘Organ of Corti’ is related with the sense of: [UP CPMT’15] (1) Taste (2) Smell (3) Hearing (4) Equilibrium 223. Proprioceptors are associated with: [UP CPMT’15] (1) Sense of touch (2) Sense of temperature (3) Internal body pressure (4) Auditory sense 224. The primary neurotransmitter at the neruromuscular junction is: [AMU’15] (1) Dopamine (2) Adrenaline (3) Acetylcholine (4) Acetaldehyde 225. The body temperature regulatory centre in the brain is: [KERALA’15] (1) Cerebellum (2) Corpus callosum (3) Hypothalamus (4) Hippocampus 226. The anterior portion of the sclera is called:[KERALA’15] (1) Lens (2) Iris (3) Pupil (4) Cornea 227. The projecting ridge in ampulla of semicircular canals in ear is called: [KERALA’15] (1) Succus entericus (2) Maccula (3) Otolith (4) Crista ampullaris

211.

212.

213.

214.

215.

216.

(1) A- Retina- contains photo receptors- rods and cones (2) B- Blind spot - has only a few rods and cones (3) C- Aquous chamber- reflects the light which does not pass through the lens (4) D- Choroid- its anterior part forms ciliary body One of the following ions are required for nerve- impulse transmission at the neuromuscular junction: [AMU’13] (1) Magnesium (2) Chloride (3) Calcium (4) Iron The organ of Corti is situated on the: [AMU’13] (1) Basilar membrane in the tympanic membrane (2) Reissner’s membrane in the vestibular canal (3) Basilar membrane in the median canal (4) Reissner’s membrane in the tympanic canal The following respond to pressure: [AMU’13] (1) Meissner’s corpuscle (2) Paccinian corpuscle (3) Bulbs of Krause (4) Organ of Ruffini How do parasympathetic neural signals affect the working of the heart? [AIPMT’14] (1) Reduce both heart rate and cardiac output (2) Heart rate is increased without affecting the cardiac output (3) Both heart rate and cardiac output increase (4) Heart rate decreases but cardiac output increases Injury localized to the hypothalamus would most likely disrupt: [AIPMT’14] (1) Short- term memory (2) Co-ordination during locomotion (3) Executive functions, such as decision making (4) Regulation of body temperature Which one of the following statements is not correct? [AIPMT’14] (1) Retinal is the light absorbing portion of visual photo pigments (2) In retina the rods have the photo-pigment rhodopsin while cones have three different photo-pigments (3) Retinal is a derivative of vitamin C (4) Rhodopsin is a purplish red protein present in rods only

814

BIOLOGY

EXERCISE - 3 | Test Yourself 1.

2.

3.

4. 5.

6. 7.

8. 9.

10.

11. 12.

The pre- ganglionic fibres of PSNS are (1) Medullated and shorter than post-ganglionic (2) Longer and myelinated (3) Non-medullated and shorter (4) Longer and non-medullated In case of spinal nerves the efferent fibres have their cell bodies in the (1) White matter (2) Gray matter (3) Out side spinal cord (4) None of these In human the total number of motor cranial nerves (in pairs) is (1) Three (2) Four (3) Five (4) Six Nerve fibres of SNS pass through (1) Spinal nerves (2) Cranial nerves (3) Both of these (4) Vagus only At resting stage the axon membrane is (1) Impermeable to sodium and potassium (2) More permeable to sodium (3) Equally permeable for sodium and potassium (4) None of these Interneurons are not functional in the following Reflex (1) Stretch (2) Visual (3) Swallowing (4) Withdrawl After sympathectomy all of the following are the effects in our body, except (1) Miosis (2) Bradycardia (3) Bronchodilatation (4) Decrease of B. M. R If vagus is stimulated the heart beat will (1) Increase (2) Decrease (3) Show no change (4) Stop Which of the following structure in human brain shows gyri and sulci (1) Mid brain (2) Cerebellum (3) Medulla oblongata (4) None of these Synaptic delay is due to (1) Accumulation of lactic acid (2) Absence of acetylcholinesterase (3) Exhaustion of neurotransmitter (4) None of these. Dorsal tubular nervous system is present in (1) All chordates (2) All vertebrates (3) All deuterostomes (4) Amniotes only Which of the following activity is not controlled by cerebrum? (1) Weeping (2) Defaecation (3) Vomiting (4) Micturition

13.

14. 15.

16.

17. 18.

19.

20.

21.

22.

23.

24.

Which of the following Cranial nerve supply taste sensation in the posterior one third part of the tongue (1) Trigeminal (2) Abducens (3) Facial (4) Glossopharyngeal The following substances cross blood brain barrier (1) Insulin (2) Testosterone (3) Glucose (4) All the above Filum terminale is the posterior (1) Non-nervous part of spinal cord (2) Nervous part of spinal cord (3) Bundle of the roots of spinal nerves (4) Both (2) and (3) Which of the following structures has Acetylchline in sympathetic postganglionic neurons (1) Adrenal medulla (2) Sweat glands (3) Heart (4) Intestine Purkinje’s cells are most complex neurons of (1) Cerebrum (2) Cerebellum (3) Hypothalamus (4) Medulla oblongata Which of the following part of human brain is called Relay Centre? (1) Corpus callosum (2) Thalamus (3) Cerebellum (4) Medulla oblongata The sound in the brain is decoded in (1) Cerebellum (2) Premotor area of frontal lobe (3) Somatosensory cortex of parietal lobe (4) Temporal lobe The CSF has more concentration of the following than plasma (1) Glucose (2) Ca+2 + (3) K (4) Cl– Enzyme involved in acetylcholine synthesis is : (1) Choline acetyl transferase (2) Cholinestrase (3) Cholecystokinin (4) Glycine Movement of tongue in human is controlled by (1) Vagus (2) Glossopharyngeal (3) Both of these (4) Last cranial nerve Pons varolli in human brain lies (1) Ant. to optic chiasma (2) Post. to medulla oblongata (3) Ventral to cerebellum (4) Dorsal to diencephalon The limbic system is related to (1) Emotional behaviour (2) Coordination of muscular movements (3) Movement of eye-ball and Hallucinations (4) Motor speech area

NEURAL CONTROL & COORDINATION (PART-I & II) 25.

26.

27.

28. 29.

30.

31.

32. 33. 34.

35.

36. 37. 38.

Following does not participate in the formation of brain stem. (1) Pons varoli (2) Medulla Oblongata (3) Mid brain (4) Cerebellum SNS fibres are (1) Either sensory or motor (2) Only motor (3) Neither sensory nor motor (4) Sensory (Preganglionic) and motor (Postganglionic) Vagotomy does not prevent the increase in gastric secretion, which normally occurs in response to (1) Injection of Insulin (2) Injection of Histamine (3) Sight and smell of food (4) Emotional distrubance Visual reflex has its centre located in : (1) Occipital cortex (2) Midbrain (3) Pons (4) Medulla Which is true about spinal nerves in man?. (1) They all are motor in nature (2) They are 37 pairs in number (3) They form cauda equina (4) None of these Which of the following nervous system is called Craniosacral outflow? (1) SNS & it is Adrenergic (2) PSNS & it is Adrenergic (3) SNS & it is Cholinergic (4) PSNS & it is Cholinergic Which of the following cranial nerve does not carry autonomous fibres? (1) III (2) X (3) VII (4) V Which of the following is not the lobe of cerebrum? (1) Temporal (2) Occipital (3) Floccular (4) Parietal Which meninx is closest to the cranium? (1) Pia mater (2) Choroid (3) Arachnoid (4) Dura mater In excitable cells, repolarization is closely associated with one of the following events (1) Na+ efflux (2) Na+ influx + (3) K efflux (4) K+ influx PSNS stimulates the activity of (1) Heart and sweat gland (2) Lacrimal gland and arrector pili muscles (3) Urinary bladder and parotid gland (4) Adrenal and pancreas Which cranial nerve of human is absent in frog (1) Occulomotor (2) Abducens (3) Hypoglossal (4) Pathetic The number of ventricles in the fore brain of human is (1) Four (2) Three (3) Two (4) One Osmoregulation is controlled by (1) Medulla Oblongata (2) Cerebrum (3) Diencephalon (4) None of these

815 39.

40.

41.

42.

43. 44. 45. 46.

47.

48.

49.

Refractory period in nerve impulse is the time taken (1) For resynthesis of neurotransmitter (2) In release of neuro transmitter to stimulate the receptors at post synaptic membrane (3) For repolarization of the fibre (4) In conduction of one impulse across the complete length of the fibre. Sympathetic fibres pass through the following branch of the spinal nerve (1) Dorsal root (2) Ramus Dorsalis (3) Ramus Ventralis (4) Ramus Communicans Which of the following cranial nerve supplies ‘Organ of Corti’? (1) Third (2) Eighth (3) Tenth (4) Seventh Arrange the cardiac muscle fibres, skeletal muscle fibres and the nerve fibres on the basis of velocity of impulse conduction in descending order, i.e. from maximum to the minimum (1) Nerve fibres - cardiac muscle fibres - skeletal muscle fibres (2) Nerve fibres- skeletal muscle fibres - cardiac muscle fibres (3) Skeletal muscle fibres- cardiac muscle fibres - nerve fibres (4) Cardiac muscle fibres- skeletal muscle fibres - nerve fibres Number of cranial nerves and spinal nerves is same in (1) Frog (2) Pigeon (3) Rabbit (4) Human Which cranial nerve is also known as dentist’s nerve? (1) Facial (2) Trigeminal (3) Occulomotor (4) Glossopharyngeal The efflux of potassium ions from axoplasm produces (1) Depolarization (2) Reverse polarization (3) Hyperpolarization (4) Action potential All are None law (principle) states that (1) All stimuli produce action potentials (2) Any cell membrane can generate and propagate an action potential if stimulated to threshold value (3) Potential difference can either be 0 or 100 (4) The property of action potential is independent of the strength of depolarizing stimulus Which of the following structure is present in the ear of frog and Rabbit both (1) Fenestra ovalis (2) Organ of Corti (3) Auditory meatus (4) Pars basilaris Lens in human eye is (1) Absent (2) Biconvex and circular (3) Ectodermal and nonliving (4) Biconcave and living The rods in human eye are (1) Less sensitive to light than cones (2) Responsible for colour vision (3) Responsible for better visual acuity than cones (4) Less in number than cones

816 50.

51. 52.

53. 54.

55.

56.

57. 58.

59.

60.

61.

BIOLOGY Ceruminous glands are present in (1) Eye lids of frog (2) Eye lids of Rabbit (3) Auditory meatus of human (4) None of these Neuromast cells are sensitive for (1) Smell (2) Touch (3) Temperature (4) None of these Which part of internal ear recognizes the different frequencies of sound (1) Tectorial membrane (2) Basilar membrane (3) Tympanic membrane (4) Reissner’s membrane Macula lutea does not contain (1) Rods (2) Cones (3) Both (4) Sensory cells Tears are secreted by (1) Meibomian glands (2) Lacrimal glands (3) Harderian glands (4) Sebacious glands Vestibular and cochlear canal are separated by (1) Reissner’s membrane (2) Tectorial membrane (3) Basilar’s membrane (4) None of these Membranous labyrinth is filled with (1) Aquous humour (2) Endolymph (3) Both (4) Endolymph and perilymph Common eye defect of old age is (1) Myopia (2) Presbiopia (3) Colour-blindness (4) Astigmatism Lens in human eye is (1) Mesodermal in origin (2) Avascular structure (3) Movable along antero posterior axis (4) Opaque in nature Taste buds for sweet and sour tastes lie on tongue respectively at (1) Anterior and posterior side (2) Anterior side only (3) Posterior and lateral side (4) Anterior and lateral side Which statement regarding ‘Stapes’ is correct? (1) It lies in auditory meatus (2) It fits onto the oval window (3) It conducts sound vibrations to fenestra rotundus (4) It is analogus to Columella auris Hypermetropia (1) Is caused by weakening of iris muscles (2) Is caused by weakening of ciliary muscles (3) Develops due to shortening of the eye ball (4) Can be corrected by using diverging lens

62.

63.

64.

65.

66.

67.

68.

69.

70.

71.

72.

73.

74.

The sensory cells - ‘Rods’, in the eye are absent in (1) Blind spot (2) Yellow spot (3) Both of these (4) None of these Conjunctiva covers (1) Exposed part of the eye ball including cornea (2) Exposed part of the eye ball except cornea (3) Only Cornea & eye lids (4) Inner surface of eye lids only. In static condition the body balance is sensed by (1) Crista (2) Maculae (3) Both (1) & (2) (4) Cochlear Canal Acquous humour is secreted from (1) Iris (2) Ciliary body (3) Lacrymal gland (4) Meibomian gland Frequency of sound is discriminated by (1) The intensity of movement of basilar fibres of Cochlea (2) The type of fluid - Perilymph or Endolymph (3) The site at the Cochlear coil (4) All of these Which of the following is not a Mechanoreceptor? (1) Free nerve endings (2) Lateral line organ (3) Krause end bulbs (4) Paccinian Corpuscles Lateral flow of information in retina (1) Distorts the image (2) Sharpens the contrast (3) Makes the eyes glow (4) Segregates the colours of white light Which cranial nerve in eye helps in accommodation? (1) 3rd, 4th and 6th (2) 3rd only nd rd (3) 2 and 3 (4) 2nd only Long cilia of many hair cells of ampulla in ear are grouped together in a bundle called (1) Crista (2) Otolith (3) Macula (4) Cupula Cochlea in human contains (1) Perilymph only (2) Endolymph only (3) Both perilymph and endolymph (4) Only gelatinous material When the ciliary muscles are at rest, the eyes can (1) Focus for distant objects (2) Focus for near- by objects (3) Accommodate the light from the objects of distance 25 cm. to infinity (4) See nothing at all Cat’s eyes glow in the dark because of the presence of (1) Tapetum lucidum (2) Pectin (3) Fovea centralis (4) Pigmented choroid In vision the colour results from the (1) Different degree of diffraction by lens (2) Interaction of rods and cones (3) Different classes of rods (4) Different classes of cones

NEURAL CONTROL & COORDINATION (PART-I & II)

817

ANSWER KEY EXERCISE 1 : NCERT BASED QUESTIONS 1. 6. 11. 16. 21.

(2) (3) (3) (3) (4)

2. 7. 12. 17. 22.

(3) (2) (4) (3) (4)

3. 8. 13. 18. 23.

(4) (4) (1) (2) (4)

4. 9. 14. 19. 24.

(4) (3) (1) (3) (3)

5. 10. 15. 20. 25.

(2) (4) (4) (4)\ (3)

EXERCISE 2 : WINDOW TO COMPETITIVE EXAMS 1. 6. 11. 16. 21. 26. 31. 36. 41. 46. 51. 56. 61. 66. 71. 76. 81. 86. 91. 96. 101. 106. 111. 116. 121. 126. 131. 136. 141. 146. 151. 156. 161. 166. 171. 176.

(2) (4) (4) (3) (2) (1) (2) (2) (3) (1) (4) (3) (1) (2) (1) (2) (2) (1) (2) (3) (1) (2) (4) (2) (2) (2) (4) (2) (4) (4) (4) (3) (4) (1) (1) (1)

2. 7. 12. 17. 22. 27. 32. 37. 42. 47. 52. 57. 62. 67. 72. 77. 82. 87. 92. 97. 102. 107. 112. 117. 122. 127. 132. 137. 142. 147. 152. 157. 162. 167. 172. 177.

(4) (1) (3) (1) (1) (4) (1) (4) (4) (4) (2) (2) (2) (4) (2) (3) (2) (1) (3) (3) (2) (3) (3) (3) (3) (2) (4) (2) (1) (2) (4) (2) (4) (2) (2) (2)

3. 8. 13. 18. 23. 28. 33. 38. 43. 48. 53. 58. 63. 68. 73. 78. 83. 88. 93. 98. 103. 108. 113. 118. 123. 128. 133. 138. 143. 148. 153. 158. 163. 168. 173. 178.

(2) (3) (4) (1) (1) (4) (4) (1) (3) (4) (2) (4) (4) (2) (1) (2) (3) (1) (1) (2) (3) (1) (2) (4) (1) (3) (4) (3) (2) (3) (1) (2) (4) (2) (2) (3)

4. 9. 14. 19. 24. 29. 34. 39. 44. 49. 54. 59. 64. 69. 74. 79. 84. 89. 94. 99. 104. 109. 114. 119. 124. 129. 134. 139. 144. 149. 154. 159. 164. 169. 174. 179.

(2) (2) (4) (2) (1) (3) (2) (3) (2) (3) (2) (3) (3) (1) (2) (1) (1) (4) (2) (4) (4) (2) (3) (4) (3) (3) (1) (3) (4) (1) (4) (3) (3) (3) (3) (3)

5. 10. 15. 20. 25. 30. 35. 40. 45. 50. 55. 60. 65. 70. 75. 80. 85. 90. 95. 100. 105. 110. 115. 120. 125. 130. 135. 140. 145. 150. 155. 160. 165. 170. 175. 180.

(1) (3) (2) (2) (1) (2) (2) (1) (2) (2) (1) (1) (1) (2) (2) (2) (1) (2) (1) (2) (3) (2) (1) (3) (1) (2) (2) (1) (1) (1) (1) (3) (2) (2) (3) (3)

181. 186. 191. 196. 201. 206. 211. 216. 221. 226.

(3) (3) (1) (2) (1) (3) (3) (3) (3) (4)

182. (3) 183. (4) 187. (1) 188. (4) 192. (4) 193. (1) 197. (3) 198. (2) 202. (3) 203. (3) 207. (1) 208. (4) 212. (3) 213. (2) 217. (2) 218. (1) 222. (3) 223. (3) 227. (4) EXERCISE 3 : TEST

184. 189. 194. 199. 204. 209. 214. 219. 224.

(2) (3) (4) (1) (1) (1) (1) (4) (3)

185. 190. 195. 200. 205. 210. 215. 220. 225.

(1) (2) (1) (1) (1) (1) (4) (1) (3)

YOURSELF

1. 2.

(2) (2)

In SNS these fibres are shorter and myleinated

3.

(3)

Three (3rd, 4th and 6th) regulate eye ball movement and two ( 11th and 12th) supply neck & shouldermuscles.

4.

(1)

These fibres pass through spinal nerves of thoracic and lumber regions.

5.

(4)

It is more permeable to potassium than sodium.

6. 7.

(1) (3)

Stretch reflex is monosynaptic.

8.

(2)

PSNS fibres pass through Vagus and secrete acetylcholine to decrease the heart beat.

9.

(2)

Gyri and Sulci are also present in Cerebrum.

10.

(4)

It is the time taken by the neurotransmitter to stimulate receptors in post synaptic membrane. Exhaustion of neurotransmitter causes synaptic fatigue.

11.

(1)

It is the characteristic point of all chordates

12.

(3)

13.

(4)

Vomiting is a reflex action controlled by medulla oblongata. 14. (3)

15.

(1)

16.

(2)

The nervous part of the spinal cord is called cauda equina. 17. (2)

18.

(2)

Thalamus is the part of fore brain.

19. 20.

(4) (4)

Cerebellum is for balancing the body. 21. (1)

22.

(4)

The last cranial nerve is called hypoglossal.

23. 24.

(3) (1)

It regulates on and off switch for breathing.

25.

(4)

26.

(2)

Brain stem is formed by Mid brain, Pons varolli and Medulla oblongata. The fibres of PSNS are also motor in nature.

818

BIOLOGY

27. 28.

(2) (2)

29. 30. 31.

(3) (4) (4)

32. 33.

(3) (4)

34. 35.

(3) (3)

36.

(3)

37.

(2)

38.

(3)

39.

(3)

40.

(4)

41. 42.

(2) (2)

43. 44.

(1) (2)

45.

(3)

46. 47.

(4) (1)

48. 49. 50.

(2) (3) (3)

Occipital cortex is the area for vision and visual interpretation. Spinal nerves are mixed, and 31 pairs in number. The SNS is Thoraco- lumber outflow. Fibres of Autonomous nervous system pass through 3rd, 7th, 9th and 10th Cranial nerves. The fourth lobe of cerebrum is frontal. Dura mater, of white fibrous connective tissue, is protective in nature. The activity of heart, arrector pilli muscles and Adrenal is stimulated by SNS. Frog has only 10 pairs of cranial nerves. Hypoglossal is 12th cranial nerve in human. Ventricles number I, II and III are present in forebrain. Hypothalamus part of Diencephalon regulates osmotic concentration. Refractory period is 1/1000 of a second for an average sized neuron Ramus Communicans is the thinnest branch of spinal nerve. 8th cranial nerve is auditory. The velocity of nerve impulse is approximately 100 m. per second and velocity of cardiac impulse is about 0.6 m. per second Cranial nerves and spinal nerves are 10 pairs each. This nerve supplies the gums of upper Jaw and lower Jaw. In hyper-polarization the potential difference may reach up to - 80 mV. Organ of Corti and Auditory meatus are absent in frog while Pars basilaris is absent in rabbit. Lens is biconvex, circular, ectodermal and living Cones are less in number and sensitive to colours. These glands secrete Cerumen (Ear wax)

51.

(4)

52.

(2)

53.

(1)

54.

(2)

55.

(1)

56.

(2)

57.

(2)

58. 59. 60. 61.

(2) (4) (2) (3)

62. 63.

(3) (2)

64. 65. 66.

(2) (2) (3)

67. 68.

(3) (2)

69.

(2)

70. 71.

(4) (3)

72.

(1)

73.

(1)

74.

(4)

These cells are sensitive for water vibrations (Rheoreceptor) The highest and the lowest frequencies of sound are recognized by the outermost and the innermost coils of the cochlea, respectively. This is also known as yellow spot and contains cones only. Meibomian glands produce oily secretion for lubrication. Basilar membrane separates tympanic canal from cochlear canal. Perilymph is present in Vestibular canal and tympanic canal Biconvex lens is used for correcting this disorder. Posterior side contains taste buds for bitter taste. Stapes is homologus to Columella auris. In this defect the image is formed behind the eye ball. Yellow spot contains only cones. The cornea of the eye is not covered by conjunctiva. Aqueous humour nourishes the lens and cornea. The intensity of movement of basilar fibres regulates the loudness or amplitude of sound. Krause end bulbs are sensory for cold The cells for lateral flow are horizontal and Amacrine. For accommodation the fibres of PSNS pass through Occulomotor nerve. Cupula is present in semicircular canals. The cochlear duct contains endolymph and other two contain perilymph. For nearby objects the focal length of the lens is reduced. Tapetum lucidum is present behind retina and contains Guanin crystals. Cones are sensory form three different colours – red, green & blue.

Chapter

22

Chemical Coordination & Integration Chemical Coordination & Integration While going through the chapter pay special attention to the following – Terms and Definitions – 1. Pheromones 4. Somatomedins 7. Brain sand 10. Eunuchoidism

2. 5. 8. 11.

Prostaglandins Antidiuresis Adenohypophysis Neuro hormones

3. 6. 9.

Hypophysis Isthmus Islets of Langerhans

Differences – 1. Diabetes mellitus and Diabetes insipidus 2. Cushing’s syndrome and Conn’s syndrome 3. Pseudo-pregnancy and Pseudo-precocity 4. Hypoparathyroidism and Hyperparathyroidism 5. Corticotropins and Corticoids 6. Hormones and Parahormones 7. Hypoglycemia and Hyperglycemia 2. 5.

Bayliss and Starling Von Euler

3. 6.

Thomas Addison Karlson

Hormones/Chemicals – 1. Catecholamines 4. Aldosterone 7. Parathormone 10. Erythropoetin

2. 5. 8. 11.

Insulin Vasopressin Melatonin Enterogastrone

3. 6. 9.

hCG Progesterone Secretin

Diseases / Disorders – 1. Cretinism 4. Myxoedema 7. Gynaecomastia

2. 5. 8.

Tetany Glycosuria Osteoporosis

3. 6. 9.

Acromegaly Addison’s disease Simmond’s disease

There are two types of coordinating systems in the body, i.e. (i) Hormonal (chemical) coordination and (2) Nervous (Neural) coordination

3. Its effect is wide spread. 4. Its effect is long lasting.

3. 4.

  

NERVOUS COORDINATION Nervous tissue is purely ectodermal in origin Nervous coordination (conduction of impulses) is rapid. Its effect is localized. Its action is of shorter duration.

Parahormones/ local hormones

Pheromones or ecto hormones/ semiochemicals Endocrine glands

           

Biologists – 1. F Sanger 4. Banting and Best

HORMONAL COORDINATION 1. Hormonal tissue is epithelial (ecto/ 1. meso/ endodermal) in origin 2. Hormonal coordination is slow. 2.

At a Glance

Pituitary gland Pineal gland

Thymus gland Gonads

Placenta

Gastro-intestinal tract (git) Pancreas

Thyroid gland Adrenal gland Kidney Heart

Hormonal action

820

BIOLOGY 

The study of endocrine glands is called Endocrinology.



Father of endocrinology is Thomas Addison.



Endocrine glands pour their secretion directly into the blood or body fluid. Such secretions are not carried through ducts. The endocrine gland are, therefore, also known as ductless glands.

duct

Blood with Hormone

blood

(A)

(B) Fig. 22.1 (A) Exocrine gland, (B) Endocrine gland



The secretions of endocrine glands are called hormones, means to excite or stimulate.



Secretin was the first hormone, discovered by Bayliss and Starling (1902).



The term ‘hormone’ was coined by Starling (1905).

PARAHORMONES/ LOCAL HORMONES   

Parahormones are short-lived chemicals which are produced from almost all body cells (except mammalian RBCs). These chemicals affect the functioning of either the neighbouring cells (Paracrine hormones) or the same cells from which they are secreted (Autocrine hormones). Most of the local hormones are paracrine type and include Prostaglandins, Neurotransmitters and Interferons etc.

(a) Prostaglandins •

They were discovered by Von Euler (1935) in the semen of human and were thought to be the secretion of Prostate glands, and hence named so.

•

They are derivatives of polyunsaturated fatty acids (eg. Arachidonic acid).

•

They regulate BP by contraction and relaxation of smooth muscles of blood vessels.

•

These chemicals also regulate Peristalsis and secretion of the digestive juices.

•

They cause pain at injury site and induce fever. They also promote inflammation. (The pain killers inhibit the secretion of prostaglandins).

•

Prostaglandins also cause contraction of uterine muscles, vas deferens and oviduct etc.

(b) Neurotransmitters/ neuro-regulators •

These chemicals are peptides and are synthesized in the nerve cells.

•

They help in transmitting nerve impulses to muscles/glands or across the synapses.

•

Neuro-regulators are of two types, 1. 2.

Excitatory - eg. Acetylcholine, Nor-epinephrine, Serotonin and Dopamine etc. Inhibitory– eg. Glycine, Gamma Amino Butyric Acid (GABA), Endorphins and Nitric Oxide (NO) etc.

CHEMICAL COORDINATION AND REGULATION

821

(c) Interferons •

They are low molecular weight proteins secreted by virus infected cells and provide resistance to the neighbouring cells ((For details please refer ‘Immune system’ )

PHEROMONES or ECTO HORMONES/ SEMIOCHEMICALS     

The term ‘pheromone’ was given by Karlson. The pheromones are volatile and odorous. They travel through air and alter the functioning of the other members of the same species. The ‘confusion technique’ is based upon the use of pheromones. The important examples of pheromones are bombycol, geradioal and muskone. Bombycol is secreted by Bombyx mori ( Silkmoth ) as a sex attractant for mating. This was the first pheromone discovered. Geradiol is secreted by honey bees for aggregation and muskone is secreted from musk deer.

hypothalamus

pineal gland

pituitary gland (hypophysis) thyroid gland

parathyroid gland

thymus

adrenal gland

pancreas ovary

testis Fig. 22.2

Human endocrine glands

ENDOCRINE GLANDS Chemical nature of hormones 1. Amino acid derivatives eg. Thyroxine, adrenaline (both tyrosine derivatives) and melatonin (tryptophan derivative). 2. Steroids (lipids) – They are cholesterol derivative. eg. Estrogen and progesterone (from ovary and placenta) testosterone (from testis) and hormones of adrenal cortex (Corticoids). 3. Peptides/ proteins – The maximum of the hormones are peptides or proteins. Some are glyco-proteins (FSH, LH, TSH & hCG) while others are pure proteins, eg. Hormones of Pancreas, Parathyroid, Pituitary and thymus.

822

BIOLOGY

(1) Pituitary Gland •

It is called master gland (master of endocrine orchestra) as it regulates the functioning of other endocrine glands like thyroid, Adrenal cortex, testes and ovaries etc. However, the secretions of pancreas, thymus and pineal body are not regulated by the hormones of pituitary.

•

Pituitary is a single or unpaired gland weighing about 0.5 gm.

III Ventricle (Diocoel) Infundibulum

Pars eminence

Pars tuberalis

Middle lobe (Pars intermedia) Posterior lobe (Pars nervosa) Sella tursica (cavity) Sphenoid bone

Anterior lobe (Pars distalis) Fig. 22.3

Pituitary Gland

•

It is present in the ‘Sella tursica’ cavity of Basi-sphenoid bone, and is attached to the floor of Diencephalon (hypothalamus) of fore brain through a stalk called Infundibulum.

•

As it is present below diencephalon of fore-brain it is also known as Hypophysis cerebri.

•

In mammals it is ectodermal in origin.

•

It consists of two-parts - (1) Adenohypophysis, and

(2) Neurohypophysis

(1) Adenohypophysis It develop from Rathke’s pouch, a diverticulum of buccal cavity and includes (i) Anterior lobe ((pars distalis) and (ii) Middle lobe ((pars intermedia) (2) Neurohypophysis It is directly connected to the Hypothalamus (diencephalon) part of the forebrain. It includes posterior lobe ((pars nervosa) (A) Anterior lobe - 6 hormones (i) Growth hormone or somatotrophic hormone (STH) (ii) Prolactin (PRL) or mammotropin or LTH (Leuteotropic Hormone) (iii) Adreno corticotropic hormone (ACTH) (iv) Thyroid stimulating hormone (TSH) (v) Follicle stimulating hormone (FSH) (vi) Leutinizing hormone (LH) [STH & PRL are secreted from Acidophilic (40%) cells; ACTH is secreted from chromophobic cells, while rest three, TSH, FSH & LH are secreted from Basophilic (10%) cells.] • Last three hormones, TSH, FSH and LH, are glycoproteins while the first three are peptides/ proteins. •

Except prolactin all other hormones of anterior pituitary are Tropic hormones because they stimulate other endocrine glands. Prolactin hormone stimulates mammary glands which are not endocrine but exocrine in nature.

CHEMICAL COORDINATION AND REGULATION Growth Hormone (STH) • It is anabolic hormone and stimulates protein synthesis. The catabolism of proteins and amino acids is decreased. • It stimulate lipolysis, i.e. break down of lipids for energy production. • It decreases the use of glucose for energy production and conserves carbohydrates as glycogen. • It reserves calcium and phosphate and causes the elongation of bones. Hyposecretion of STHIn children – Dwarfism, producing ‘Midgets’ with stunted growth In adults – Simmond’s disease (protein synthesis is decreased and lactation, in females, is reduced) Hypersecretion of STH– In children – Gigantism (over growth of the body) In adults – Acromegaly, i.e. gorilla appearance (free ends or extremities like fingers, toes, chin etc. are elongated). The affected person develops Osteoarthritis, Gynecomastia and Hirsutism (showing presence of coarse & pigmented hair on chestback etc. (ii) Prolactin (PRL) • It stimulates mammary glands for the synthesis of milk.

823

(i)

• It is a non-tropic hormone. (iii) Adreno corticotropic hormone (ACTH) • It stimulates the secretion of corticoids from Adrenal cortex. • It also regulates melanin pigment in human skin. (iv) Thyroid stimulating hormone (TSH) • It stimulates the growth of thyroid follicles. • It also promotes the utilization of iodine by the gland, for the synthesis of thyroxine. (v) Follicle stimulating hormone (FSH) • It is commonly called Gametogenic hormone as it regulates Spermatogenesis in males and Oogenesis in females. • In females it also stimulates ovarian follicles for the secretion of estrogen hormone. (vi) Leutinizing hormone (LH) • It is responsible for ovulation, i.e. release of female gamete from the ovary. • It also helps in the formation of Corpus luteum. • It stimulates corpus luteum for the synthesis of mainly progesterone hormone. • In males, this hormone stimulates interstitial cells or Leydig cells, for the synthesis of ‘testosterone’ and is, therefore, called as Interstitial cells stimulating hormone (ICSH). Hypothalamic control over Anterior Pituitary – The chemical factors, released from hypothalamus affect the secretions of anterior pituitary through the hypophyseal portal system. Following are the six releasing factors or hormones. (1) Growth hormone releasing factor (hormone) – GRH It stimulates the secretion of growth hormone from anterior pituitary. (2) Growth hormone release inhibiting hormone – GIH It is also known as Somatostatin and inhibits the secretion of growth hormone from anterior pituitary. (3) Thyrotropin releasing hormone – TRH It stimulates the secretion of thyroid stimulating hormone (TSH or thyrotropin) (4) Corticotropin releasing hormone - CRH It stimulates the secretion of ACTH. (5) Gonadotropin releasing hormone – Gn RH It stimulates anterior pituitary for the secretion of FSH and LH (6) Prolactin inhibitory hormone – PIH [The production of prolactin releasing hormone (PRH) is doubtful in human.]

Connecting Concepts  Growth hormone is considered to be a tropic hormone though it does not affect the endocrine organs directly. It stimulates liver for the secretion of a hormone like chemical, Somatomedin. This hormone (somatomedin) then stimulates the growth of bones, muscles or body organs.

824

BIOLOGY (B) Middle lobe (i) Intermedin hormone • It is secreted in fishes, amphibians and reptiles. • It causes darkening of skin by dispersing pigmented cells (Chromatophores). (ii) Melanocyte stimulating hormone - MSH • It is secreted in birds and mammals. • It also causes darkening of skin by synthesizing more melanin and by causing dispersal of melanocytes. In human the middle lobe is rudimentary and MSH is either vestigial or is not secreted in adults. The dispersal of melanocytes or the skin pigmentation in human is regulated by ACTH

Check Point 1. Fill in the blanks : (i) ............................. of pituitary develops from Rathke’s pouch. (ii) Leutinizing hormone in males is called ............................. (iii) ............................. is also known as somatostatin. (iv) The hormones of anterior pituitary are chemically ............................. (v) ............................. coined the term ‘Hormone’. (vi) ............................. was the first hormone to be discovered. (vii) Prostaglandins and Interferons are included in the category of ............................. (viii)Posterior pituitary is under the direct control of ............................. (ix) Sella tursica, the cavity of Basisphenoid lodges ............................. gland. (x) Deficiency of ............................. hormone causes diabetes insipidus.

(C) Posterior lobe – The hormones of posterior lobe of pituitary are actually produced from the axons of neurons of hypothalamus. These hormones are, therefore, called Neurohormones. There are two neurohormones secreted (released) from posterior pituitary. (i) Oxytocin (Pitocin) • It is a small peptide of 9-amino acids. • It causes contraction of smooth muscles, mainly of mammary glands and uterus. • The contraction of mammary glands causes release of milk and the hormone is, therefore, called as ‘Milk-let-down factor’. • The contraction of smooth muscles of uterus during matured pregnancy causes expulsion of child (parturition). This hormone is therefore, also known as ‘Birthhormone’. (ii) Vasopressin (Pitressin) • It causes constriction of blood vessels and raises blood pressure. • It also helps in absorption of water from glomerular filtrate in uriniferous tubules of kidney. Thus, it reduces the amount of water in urine and hence concentrates it. • This hormone is commonly called as Anti-diuretic hormone (ADH) Hyposecretion of ADH – In such a condition the water absorption is reduced and the amount of water in urine is increased. This condition of diluted urine (Diuresis), without sugar or glucose, is called Diabetes insipidus. (It is different from Diabetes mellitus in which sugar/glucose passes with urine).

(2) Pineal Gland • •

Check Point 1. Match the followings : 1. Oxytocin A. Gametogenic hormone 2. Pituitary B. Antiageing hormone 3. FSH C. Birth Hormone 4. Vassopressin D. Hypophysis cerebri 5. Pineal body E. Non-tropic hormone 6. Melatonin F. Vestigial hormone 7. Prolactin G. ICSH 8. MSH H. ADH I. Seat of soul J. Pheromone

• • • •

It is ectodermal in origin. It is unpaired (Single) and is attached to epithalamus of diencephalon. It is therefore, also known as Epiphysis cerebri (Pituitary, attached to hypothalamus, is called Hypophysis cerebri) It is considered to be the ‘seat of soul’. In human it starts degenerating at the age of 7-8 years. The calcium and magnesium salts are deposited in this gland at later stages and the structure is then known as ‘brain sand’. This gland produces single hormone melatonin which is biogenic amine.

Melatonin – • • • • •

It is derivative of amino acid – Tryptophan It causes lighting of skin and is antagonistic to MSH. It delays sexual maturity by influencing the development of gonads and release of gonadotropin hormones from pituitary. Its secretion is increased during darkness. As it delays puberty, It is also known as anti-ageing hormone (the pacemaker for ageing is, however, Thymus gland gland). It maintains biological clock in human body. It also maintains diurnal variations (circadian rhythm) in animals and decides the breeding season in them.

CHEMICAL COORDINATION AND REGULATION

825

(3) Thymus Gland

Check Point

•

It is single, bilobed and endodermal.

•

It lies close to heart on the ventral side.

•

It is differentiated into outer-cortex and inner-medulla. The medulla contains two onion shaped Hassel’s corpuscles.

•

It is highly developed at puberty and later degenerates with the advancement of age.

•

It is lymphatic organ as well as an endocrine gland.

•

It produces T-lymphocytes and is related to immune system.

•

The hormone of this gland is called Thymosin or Thymitin.

•

[Do not confuse this hormone with Thymine (a nitrogenous base) and Thiamine – Vitamin B1.]

It is peptide and stimulates the production of lymphocytes from other lymphatic tissues.

(4) Gonads A. Testis It contains large number of seminiferous tubules. In between seminiferous tubules the endocrine cells, called Leydig cells or Interstitial cells are present. Inside seminiferous tubules, there are non-dividing , diploid and supporting cells, called Sertoli cells. Besides nourishing the developing sperms, the sertoli cells also secrete hormones. Two hormones, released from testes, are -

Sertoli cell

Leydig's cells or Interestitial cells Seminiferous tubules

(1)

(2)

Fig. 22.4 C.S. Testis Testosterone – • It is steroid (cholesterol-derivative) in nature. • It is secreted from Leydig’s cells under the influence of interstitial cell stimulating hormone (ICSH) of anterior pituitary. • It promotes the development of reproductive organs in males. (Before birth, it stimulates descent of testes into scrotum). • It also helps FSH of anterior pituitary in spermatogenesis process. • It is responsible for the development of secondary sexual characters also, like beard, moustaches, low pitch voice and body musculature, in males. Inhibin – • This is secreted from sertoli cells under the influence of FSH from anterior pituitary. The Sertoli cells also secrete Androgen Binding Protein (ABP) that concentrates testosterone hormone in seminiferous tubules.

•

Excess of inhibin hormone, by feed back mechanism, inhibits the secretion of FSH.

•

Inhibin is also secreted in females by granulosa cells.

1. Differentiate between : (i) Duct glands and ductless glands (ii) Hormonal coordination and nervous coordination (iii) Somatomedin and Somatostatin (iv) Leutinizing Hormone and Leuteotrophic hormone (v) Thymosin and thymine

826

BIOLOGY B. Ovary It contains a large number of Graafian follicles (the term, used for ovarian follicles in mammals). The connective tissue of ovary is called Stroma. Following hormones are secreted from ovary. Ovarian follicle approaching maturity Primordial follicle Mature Germinal ovarian epithelium follicle Blood vessels Theca folliculi Mesovarium Liquor foliculi Fibrous corpus albicans

Ruptured follicle Ovulation Secondary oocyte Medulla Fully formed corpus luteum

(1)

(2)

(3)

(1)

Corpus luteum forming

Fig. 22.5 C.S. of Mammalian ovary Estrogen (Steroid)• It is secreted from the cells of Stratum granulosum. The granulosa cells or follicular cells form internal coating to theca folliculi. • FSH of anterior pituitary stimulates the secretion of this hormone. (Estrogen is also secreted from corpus luteum). • Estrogen stimulates the development of reproductive organs like oviduct, uterus, vaginal tube etc. • It stimulates the development of secondary sexual characters also, i.e. high pitch voice, female body musculature, development of breasts and pattern of pubic hair distribution. • It also helps in Oogenesis process and regulates menstrual cycle. Progesterone (Steroid) • This hormone is secreted from Corpus luteum (means yellow body). • It is responsible for implantation of embryo and maintenance of pregnancy. • It also stimulates mammary glands for storing and secreting milk. • It is commonly called Pregnancy hormone. • Progesterone inhibits ovulation, maturation of Graafian follicles and abortion. Relaxin (Peptide) • It is also secreted from corpus luteum. • It dilates or relaxes pubic symphysis and cervix to help in parturition (child birth) at the end of pregnancy. (Relaxin hormone is also produced from prostate glands in males and placenta, mammary glands and uterus in females) Following conditions may arise from abnormal functioning of gonadal hormones (and/or the sex hormones of Adrenal gland) Sexual pseudoprecocity • This developes due to hypersecretion of sex hormones. • In male children (boys) it is due to excess of testosterone hormone. It causes enlargement of penis and early appearance of pubic and axillary hair, faster body growth and masculinisation. The spermatogenesis, however, does not occur.

CHEMICAL COORDINATION AND REGULATION •

In female children (girls) this arises from increased amount of estrogen hormone. The secondary sexual characters develop but ovulation does not start.

In case of true sexual precocity or Precocious puberty the gonads are matured earlier and production of gametes also starts. In females this may begin by the age of 9 years and in males by 10 years. Eunuchoidism • It develops due to failure of testosterone secretion. The accessory sexual organs like penis, prostate glands and seminal vesicles remain infantile or smaller in size. The secondary sexual characters of males fail to develop. Gynaecomastia • It is due to disturbance of ‘estrogen to androgen’ ratio. •

(2)

(3)

•

The amount of circulating estrogen (from adrenal gland) increases in males. This causes development of breasts.

•

The decrease in the amount of testosterone in later life of males can also produce such symptoms.

(5) Placenta In females the placenta acts as a temporary endocrine gland during pregnancy. It secretes following hormones– (i) Human chorionic gonadotropin (hCG) • Chemically it is a glycoprotein. •

It passes out through urine and can be used for Gravi-index test, commonly called pregnancy test.

This hormone prolongs the life of corpus luteum, which in turn secretes progesterone for maintaining pregnancy. (ii) Human chorionic somatomammotropin (hCS) • It is a peptide hormone which has growth-stimulating and lactogenic activity. •

•

The structure of this hormone is very similar to human growth hormone, and therefore it is inappropriate to call it prolactin or chorionic mammotropin. (iii) Relaxin • It is a peptide hormone and softens the connective tissue of pubic symphysis. It is not significant in human. (iv) Chorionic thyrotropin • Its function is similar to TSH. (v) Chorionic corticotropin • It is also a peptide hormone and is similar in function to ACTH of anterior pituitary. (vi) Estrogen (Steroid) and Progesterone (Steroid) These hormones are also secreted from placenta. The amount of hCG decreases after the initial rise but estrogen and progesterone secretion increases until just before parturition. The function of these hormones is similar to the hormones of ovary.

(6) Gastro-Intestinal Tract (Git) The endocrine cells of gut together form a mass bigger than any other endocrine gland of the body. It secretes following hormones. (i) Gastrin • It is secreted from mucosa of pyloric stomach. (ii)

• It stimulates the secretion of gastric juice and HCl. Enterogastrone – • It is secreted from duodenal mucosa. •

It inhibits the secretion of gastric juice and also regulates the mobility of food in gut.

827

828

BIOLOGY [Two other hormones, GIP (Gastric inhibitory polypeptide) and VIP (Vasoactive Intestinal polypeptide) have also been known to inhibit gastric secretion]. (iii) Secretin • It is also secreted from duodenal mucosa. It stimulates Pancreas for the secretion of bicarbonates and fluid in pancreatic juice. It, thus, increases the amount of pancreatic juice. (iv) Cholecystokinin (CCK or Pancreozymin )• It is also secreted from duodenal mucosa. •

• (v)

It stimulates pancreas for the secretion of enzymes in pancreatic juice.

• It also causes contraction of gall bladder for the release of bile juice. Hepatokinin • It is also secreted from duodenal mucosa.

• It stimulates liver for the synthesis of bile juice. (vi) Enterocrinin • It is secreted from the mucosa lining of ileum. •

It stimulates intestinal glands for the secretion of intestinal juice (Succus entericus)

(7) Pancreas It lies in the coil of duodenum. It is about 15 cm. long and weighs about 80 g. It is a mixed (composite heterocrine) gland. Its exocrine part includes Acini and produces pancreatic juice. Its endocrine part consist of a large number of cell – groups, called Islets of Langerhans (identified and named by Paul Langerhans, 1869). The islets of Langerhans contain three types of cells. 1. Alpha (α) cells = 10-20% 2. Beta (β) cells = 70-80% 3. Delta (δ) cells = ~5% (i) α-Cells •

They are acidophilic cells and secrete Glucagon hormone.

•

This hormone is peptide in nature (consists of 29 amino acids).

•

It was 1st Isolated in pure crystalline form by Kimbell and Murlin (1923).

•

It is glycogenolytic (in liver, not in muscles) and causes breakdown of glycogen into glucose. Glucagon

Glycogen → Glucose

β-cells (~75%)

Acini α-cells (~20%)

Aciner cell

δ-cells (5%)

Fig. 22.6 C. S. pancreas

•

It increases the amount of glucose in blood and is therefore called hyperglycemic factor.

•

It is gluconeogenetic also and produces glucose from non-carbohydrate sources, like – amino acids and fatty acids.

CHEMICAL COORDINATION AND REGULATION •

It also reduces the uptake and utilization of glucose by the cells.

•

It is lipolytic and ketogenic.

•

The α-cells are damaged by Cobalt chloride.

(ii) β-Cells •

These cells secrete another peptide hormone, i.e. Insulin.

•

Insulin contains zinc and sulphur

•

It was first isolated in pure, crystalline form by Banting and Best (1922), and they were awarded Nobel prize for this discovery.

•

829 Connecting Concepts  Both, STH of anterior pituitary and insulin, are anabolic hormones which conserve carbohydrates and stimulate protein synthesis. But STH is lipolytic while insulin in lipogenic.

Connecting Concepts The molecular structure of insulin was discovered by F. Sanger, (was awarded Nobel  Ketone bodies (Ketosis) — prize).

 When there is excess Acetyl-CoA in

•

Each molecule of insulin consists of 2-polypeptide chains (1 α−chain, having 21 the body, some of it gets converted in amino acids, and one β-chain, having 30 amino acids.) to acetoacetyl-CoA which in liver (unlike

•

It is glycogenic (causes glycogenesis), i.e. converts glucose into glycogen in liver as other tissues) changes to Acetoacetate (free form). well as muscle cells.

•

It is hypoglycemic factor, i.e. it decreases the amount of glucose in blood. The insulin  The Free acetoacetate (β-Keto acid) is converted to β-Hydroxybutyrate is, therefore, antagonistic to glucagon.

•

Insulin increases the permeability of plasma membrane of the cells to increase the Acetoacetate, β-hydroxybutyrate and diffusion of glucose into cells to produce energy. It prevents break down of lipids acetone are called ‘Ketone bodies’. and proteins.

and acetone. These compounds, i.e.

•

It is lipogenic and helps in synthesis of fat from glucose. It also inhibits the break down of glucose ((glycolysis). Hyposecretion of insulin • It causes hyperglycemia as the amount of glucose is increased in blood. As the permeability of the plasma membrane is decreased the cells can not utilize this glucose for energy production. The glucose, therefore, passes with urine (glycosuria). Moreover, there is accumulation of Ketone bodies in blood.

 (These compounds metabolize in liver with difficulty and diffuse into circulation. The other tissues, however, transfer CoA from succinyl-CoA to acetoacetate and then metabolize ‘active’ acetoacetate to CO2 and H2O via citric acid cycle. 

The normal ketone level in

•

The passing of glucose in urine due to deficiency of insulin in called Diabetes mellitus human is 1 mg/100 ml. of blood. The (compare it from Diabetes incipidus). It is more a disease of lipid metabolism than ketone bodies are normally metabolized as rapidly as they are formed. But if the carbohydrate break down.

•

The person feels more thirst (polydypsia) and consumes more food (polyphagia).

•

The break down of muscular tissue produces loss of weight and tiredness.

•

Retinal damage begins.

•

The healing is also delayed. Alloxan damages β-cells and produces the symptoms of Diabetes mellitus Hypersecretion of insulin • It causes hypoglycemia (The amount of blood glucose is decreased) •

The other symptoms of hypersecretion are irritability, double vision and sweating.

•

Hypoglycemia may produce Coma in certain cases.

•

It acts as paracrine factor to inhibit the secretions of α−cells and β−cells.

•

It also stimulates collagen formation.

entry of acetyl CoA into citric acid cycle is depressed because of decreased supply of glucose products, or if the entry of acetyl-CoA into CAC doesn’t increase with its increased production, the acetyl Co-A accumulates and more acetoacetyl - CoA is formed, and more free acetoacetate is produced in the liver.

 Three conditions lead to deficient supply of intracellular glucose : Starvation, Diabetes mellitus and high (iii) δ-Cells fat - low carbohydrate diet. The ketone • These cells secrete somatostatin hormone, also known as ‘growth hormone-release- bodies in blood (Ketosis) produces acidosis and dehydration, resulting inhibiting-hormone’ (GHRIH). into coma, in Diabetes mellitus.

(8) Thyroid Gland •

It is single and bilobed gland present on either side of trachea below larynx The 2-lobes remain connected by a non-glandular tissue called Isthmus.

•

It is endodermal in origin

•

It is the largest endocrine gland in the body (weighing ~35gm).

830

BIOLOGY Hyoid bone Thyroid cartilage (Larynx) Thyroid gland

Colloid

Isthmus of thyroid gland Follicle cells

Trachea (A)

(B)

Fig. 22.7 (A) Thyroid gland, (B) Thyroid follicle

Hormones – 3-important hormones are secreted from thyroid gland, i.e. Calcitonin, T3 and thyroxine (T4). (i) Calcitonin (or Thyrocalcitonin) –

Check Point 1. Match each item of Column A with the Two items of Column B. Column A Column B 1. Thyroxine A. Contraction of gall bladder 2. Insulin B. Descending of Testes into scrotum 3. CCK C. Pregnancy Test 4. TestoD. Hypersterone glycemia 5. hCG E. Inhibits secretion of gastric juice F. Moustaches and Beard G. Metamorphosis in Tadpole H. Pancreatic enzymes I. Polydypsia J. Gluconeogenesis K. Maintenance of corpus-luteum L. Basic metabolic rate

•

It is proteinaceous and non-iodinized hormone (Iodine absent).

•

It is secreted from C (clear) – cells or Parafollicular cells (outside thyroid follicles)

•

It is hypocalcimic factor and decreases the amount of Ca2+ in the blood.

•

It is angonistic to PTH (Para-thyroid hormone).

(ii) Thyroxine (T4)– • It is Tetra-ido-thyronine and is secreted from the cells of thyroid follicles. T4 with T3 are stored as a colloidal material in the follicles. • Thyroxine regulates basic metabolic rate (BMR) - stimulating heart beat, breathing rate etc. • It causes demineralization of bones in adults (by stimulating osteoclasts - the bone eating cells). • It causes hyperglycemia by stimulating glycogenolysis and Gluconeogenesis. • It causes nervous excitation also. • It is lipolytic, and can also be used for reducing body weight. • It is catabolic in nature and increases heat production/energy production. It is also known as pace-setter of the body. • In frog it causes metamorphosis in tadpole. Hyposecretion – Children – Cretinism • In this disorder the physical growth, mental growth and sexual growth in the children is retarded. Such a dwarf and sterile child is called cretin. • A cretin child shows pot-belly, Pigeon-chest and protruded tongue. Adults – Myxoedema • This disease also known as Gull’s disease. • Due to hyposecretion of thyroxine, the fat and protein metabolism is reduced and they get accumulated under the skin of the face to make it fluffy. • Such persons are lethargic (due to less energy production) and sensitive to cold (due to less heat production). Hypersecretion – • BMR increases to produce restlessness. • The body becomes lean and thin (Emaciation). • The disorder is called thyrotoxicosis or Grave’s disease*. Besides, there is bulging of eyes, called exophthalmic goiter.

CHEMICAL COORDINATION AND REGULATION •

*Grave’s disease is actually an autoimmune disease in which person produces antibodies that mimic the action of TSH and stimulate the secretion of thyroxine. This effect is not regulated by feed back mechanism.

(iii) Tri-ido-Thyronine (T3)– • • •

It is secreted in very small amount (~2% of T4). A major amount of this is formed by deiodination of T4. It is more potent than T4 and is the principal feed back regulator of TSH. It has short life span.

•

It acts with T4. It is mainly responsible for thermoregulation in the body. The thyroid gland is therefore, also known as thermostat of the body. Simple Goiter – • It is not because of hypo or hypersecretion of thyroxine, but is due to the deficiency of iodine in food. •

It is endemic in hilly areas.

•

The number of thyroid follicles or the size of thyroid gland increases due to increased amount of TSH.

•

Sea food and onion are rich sources of iodine. Now-a-days the common salt is also being iodized to prevent the occurrence of such goiters.

831 Check Point 1. Following are common names. Write the chemical names against them: (i) Male hormone. ........................ . (ii) Pregnancy hormone. ............................ . (iii) Collip’s hormone. ............................ (iv) T4 - hormone. ............................ (v) Hypocalcemic hormone .........................

(9) Parathyroid Gland •

These glands are four in number and are embedded, 2-in each lobe, in the thyroid gland.

•

They are endodermal in origin.

•

The hormone of these glands is called Parathyroid hormone (PTH) or Parathormone or Collip’s hormone (Isolated by Collip).

Parathormone (PTH) – •

Chemically it is a protein/peptide.

•

It regulates calcium and phosphate metabolism.

•

It inhibits the synthesis of collagen by osteoblast, and bone resorption by activation of various enzymes, muscle osteoclasts. contraction, blood clotting and

•

It also helps in absorption of dietary calcium from the intestine and renal tubules.

• •

Connecting Concepts  The calcium is essential for the

ossification. It depresses the activity of nervous system and acts as a sedative. It It makes the bones and teeth healthy. is however, necessary for transmission It is hypercalcemic factor (increases the amount of calcium in blood) and is of nerve impulses across synapses.

antagonistic to Calcitonin. Hyposecretion of PTH – Tetany • It shows restlessness, haemorrhage in tissues and spasmic contraction, twitches and convulsions in muscles (The neurons become depolarized even in the absence of stimuli). • Heart beat and breathing rate increases. (Deficiency causes excitatory effect on nervous system). Hypersecretion of PTH – Osteoporosis • The amount of calcium, at the cost of bones, increases in the blood (Hypercalcemia). • The bones become spongy due to removal of calcium phosphate (demineralization of bones). Such bones are easily fractured and deformed. • Ca++ prolongs systole. Therefore, hypercalcemia may cause cardiac arrest at this stage. • If hyperparathyrodism is not treated for a long, it may lead to the deposition of fibrous tissues in the cavities formed in the bones. This disorder is known as Osteitis fibrosa cystica.

Check Point Q.1. (i) (ii) (iii) (iv) (v) (vi)

Differentiate between: Pituitary dwarf and thyroid dwarf. Simple goitre and exophthalmic goitre. Osteoporosis and Osteomalacia. Diabetes mellitus and Diabetes insipidus. Calcitonin and calciferol. Simple goiter and exophthalmic goiter

832

BIOLOGY

(10) •

Adrenal Gland It is also known as Supra-renal gland and is formed by the fusion of two different tissues. The outer tissue is Cortex (~70%) and inner medulla (~30%). The cortex is mesodermal and medulla is ectodermal in origin. The adrenal gland is thus, mesoectodermal in origin. Adrenal gland

Capsule of adrenal gland

Zona glomerulosa

Kidney

Adrenal cortex

Zona fasciculata

Adrenal cortex

Adrenal medulla

Zona reticularis Chromaffin cells

Adrenal medulla

(A)

(B)

Fig. 22.8 (A) Adrenal gland, (B) V. S. Adrenal gland

I.

Adrenal Cortex (Hormones – Steroids) •

The cortex of adrenal gland consists of three zones. (i) Zona glomerulosa (outermost) – It produces mineralocorticoids. (ii) Zona fasciculata (Middle) – It produces glucocorticoids. (iii) Zona reticularis (Inner most) – It produces sex corticoids.

(A) Mineralocorticoids : 1. Aldosterone • It is the most potent mineralocorticoid. • It regulates mineral (sodium) metabolism. • It is commonly called as hypernatrimic factor since it increases the amount of Natrium (Na+) in blood. • Its secretion is regulated by Rennin-Angiotensin-system, and not by ACTH of anterior pituitary. • It promotes the absorption of sodium (Na+) from DCT and collecting tubules of nephrons. (For details of Renin-Angiotensin – Aldosterone-system, RAAS, please refer ‘Excretion’, Chapter 15) Hypersecretion – Conn’s disease • Amount of sodium increases in blood. • BP increases and hypertension develops. • As the amount of sodium increases in blood the potassium passes out through urine causing kidney failure in later stages. (B) Glucocorticoids : 2.

Cortisol • It is the most potent glucocorticoid in the body. • It is hyperglycemic factor and converts glycogen into glucose. (synergistic to Glucagon and antagonistic to Insulin). • It also causes gluconeogenesis (conversion of non-carbohydrates into carbohydrates or glucose). • It is anti-stress and anti-inflammatory. • It is anti-allergic and anesthetic also.

CHEMICAL COORDINATION AND REGULATION •

It suppresses immune system.

•

It prevents deposition of collagen fibres and relieves arthritis.

• It also stimulates RBC - production. Hypersecretion – Cushing’s syndrome • Blood glucose level rises (hyperglycemia). •

Glucose starts passing through urine (glycosuria).

•

Due to fat deposition in the back it shows buffalo-hump-condition..

833 Connecting Concepts  The over-dose of cortisol is used for suppressing immune activity for preventing the rejection during organ transplantation.

(C) Sex-corticoids : 3.

Androgens and Estrogens. • These hormones are generally secreted before sexual maturity, when the testes and ovaries are not fully developed. Hypersecretion of androgens – Adrenal virilism • It is sex reversal, ‘from female to male’, due to excess of androgens (testosterone). • The facial hair and secondary sexual characters of males develop in females. Hypersecretion of estrogens – Gynaecomastia • It is sex reversal, ‘from male to female’. •

Female-like mammary glands (breasts) develop in males. (Please refer ‘gonadal hormones’ also, for virilism and gynaecomastia). Hyposecretion of corticoids – Addison’s disease • This disorder develops due to atrophy or hypotrophy of adrenal cortex. •

Amount of both, sodium and glucose decreases in the blood.

•

There is Bronzing of skin due to hypersecretion of ACTH. (In human the skin colour is governed by ACTH and not MSH, as in other mammals.)

II. Adrenal Medulla •

It is called emergency gland and secretes adrenaline (Epinephrine) and noradrenaline (nor-epinephrine) hormones.

•

Hormones of medulla are chemically Catecholamines which are derivatives of Tyrosine (amino acid).

Adrenaline (epinephrine) •

It is commonly called as ‘emergency hormone’ or 3F – hormone (For fear, fight & flight).

•

Its secretion is regulated by SNS, and not by pituitary as in case of adrenal cortex.

•

It stimulates sweating, heart beat and breathing rate. It causes the dilation of coronary artery (supplying blood to the heart muscles), bronchioles (for increasing inspiratory volume) and pupil (for better vision)

•

It is hyperglycemic, i.e. increases the amount of glucose in blood.

•

It increases blood supply to brain and skeletal muscles also.

•

It also stimulates erythropoesis (production of RBCs).

•

It also causes alertness and piloerection (goose flesh), heart beat and breathing rate etc.

•

It promotes blood clotting for preventing excessive loss of the blood during injury/ emergency.

•

It inhibits the functions related to the alimentary canal, e.g. it reduces the secretion of saliva, gastric juice, bile juice, pancreatic juice and intestinal juice. It also slows peristalsis and inhibits food absorption. ((All above activities are related to emergency conditions in the body.)

•

Nor-adrenaline is vasoconstrictor and saves blood from excessive loss. It constricts peripheral blood vessels for raising BP also.

Check Point 1. Name the hormone that (i) Promotes loss of sodium in urine. (ii) Is secreted during emergency. (iii) Stimulates red bone marrow for RBC-production. (iv) Is responsible for Conn’s disease. (v) Is catecholamine. (vi) Is secreted from Leydig cells (vii) Is secreted from β- cells of pancreas (viii) Provides cell mediated immunity (ix) Is secreted from C- cells of thyroid (x) Regulates calcium metabolism

834

BIOLOGY

(11) Kidney It secretes erythropoietin and renin. (i) Erythropoietin •

•

This hormone is a glycoprotein and is commonly called Haematopoetin or EPO. It is secreted from peritubular capillary-network of uriniferous tubules (nephrons) of kidney. It stimulates red bone marrow for the production of RBCs (Erythropoesis)

(ii) Renin • •

It is primarily an enzyme, and is secreted from ‘Juxta Glomerular Cells’ of Juxta glomerular apparatus (JGA). It converts plasma protein – Angiotensinogen into Angiotensin-I, which changes into Angiotensin–II. The Angiotensin II stimulates adrenal cortex for the secretion of Aldosterone.

(12) Heart The heart is primarily a blood-pumping organ, but its atrial wall also secretes a hormone, called Atrial Natriuretic Factor (ANF). ANF • • • •

It promotes the loss of Natrium (Na+ - Sodium) in urine. It inhibits absorption of sodium chloride (NaCl) from collecting ducts. It also inhibits the release of renin, which through RAAS (Refer Chapter 15) increases the amount of sodium in blood. It is secreted when the osmolarity of the blood, or the blood pressure, rises.

HORMONAL ACTION Hormonal action affects metabolic changes in the target cells in three different ways 1. By altering permeability of the plasma membrane 2. Through intracellular (IInd or IIIrd) messengers 3. By altering activity of genes. On the basis of types of receptors used, the hormones fall into three categories. 1. Peptide / protein-hormones and catecholamines • • •

Insulin, glucagon, growth hormone and parathyroid hormones etc. are peptides while Adrenaline (epinephrine) is a catecholamine. Such hormones are insoluble in lipids/fats and can not enter through bilipid-plasma membrane. The ‘receptors’ for such hormones are present in plasma membrane.

2. Steroid hormones • • •

The examples of steroid hormones are estrogen, testosterone and corticoids like aldosterone and cortisol etc. These are fat soluble and can pass through bilipid layer of cell membrane to reach the cytoplasm. The receptors for such hormones are, therefore, present intracellularily.

3. Thyroid hormones (T3 & T4) • •

These hormone can also pass through plasma membrane as they are also fat-soluble. Their receptors are present inside the nucleus.

CHEMICAL COORDINATION AND REGULATION

835

Fig. 22.9 Functioning of peptides and steroid hormones

A. Steroids and thyroid hormones • •

• • •

Check Point

They readily pass through plasma membrane into the cytoplasm of target cells. Inside cytoplasm steroids bind to intracellular receptor proteins in the presence of Ca++ and form a complex, which enters into the nucleus and binds to regulatory sites on the chromosomes. The binding of the complex alters the pattern of gene expression, by initiating or suppressing the transcription of certain genes to produce specific types of mRNA. The thyroid hormones directly affect transcription of the genes as their receptors are present in the nucleus itself. The action of lipid soluble hormones is slower but long lasting. Adrenaline molecule

Disulphide bond

α-subunit

Receptor

Plasma Membrane β-subunit (A) Transmembrane or Cross Membrane receptor

Adenyl cyclase (enzyme) Mg G-protein

ATP

++

c AMP (II-Messenger)

Degraded by Phosphodiesterase (Enzyme)

Activation of Protein Kinase A

Glycogen

Glycogen phosphorylase

Glucose 1-phosphate Glucose

Plasma (cell) Membrane Out side the cell (B) Mechanism of Adrenaline Action

Fig. 22.10 Functioning of Catecholamine hormones

1. Categorize the following hormones on the basis of their receptors in body cells: (i) Cortisol (ii) Testosterone (iii) Adrenaline (iv) Insulin (v) Parathormone (vi) Thyroxine (vii) Leutinizing hormone (viii) Progesterone (ix) Growth hormone (x) Aldosterone

836

BIOLOGY

B. Peptide and catecholamines The receptors for such hormones are Transmembrane-proteins in the plasma membrane of the target cells. These receptors undergo conformational change when they bind with the hormone. • This receptor is a tetramer, made up of 2α and 2β glycoprotein subunits, bound to each other by disulphide bonds. • The α-subunits are extra cellular and bind with the hormone, whereas β−subunits are present across the membrane. The intracellular portion of β−subunit has tyrosine kinase activity. In case of Adrenaline the binding of hormone triggers the tyrosine kinase activity of β− subunits producing auto-phosphorylation. • Due to activity of β-subunit the G proteins (α-type) are activated. • Each stimulated molecule of G-protein activates the neighboring molecule of enzyme Adenyl cyclase, suspended in the inner layer of plasma membrane. (see figure) • Active Adenyl cyclase, in the presence of Mg++ catalyses hydrolysis of ATP molecules (in cytosol) into Cyclic AMP (cAMP). The cyclic AMP acts as a II-messenger for hormonal action. • Increased number of cAMP molecules in cytoplasm stimulate the molecules of a special category of metabolic enzymes, i.e. Protein kinases A. • Active molecules of Protein kinases A activate phophorylase kinases which further modify the activity of other enzymes for required metabolic processes. • An enzyme phosphodiesterase degrades the additional molecule of cAMP to bring their number to the normal. This stops the effect of the hormone on the target cell. In case of adrenaline following is the chain of enzymatic reactions : (i) 1 mol of Adenyl cyclase produces 102 mols. of cAMP (cAMP activates protein kinase A). (ii) 1 mol. of protein kinase A activates 102 mols. of phosphorylase kinases. (iii) 1 mol. of Phosphorylase kinase activates 102 mols. of Glycogen phosphorylases. (iv) 1 mol. of Glycogen phosphorylase produces 102 mols. of glucose-1- phosphate, which finally produce glucose. From 1 mol. of adrenaline hormone the net-production of glucose mols., is = (102 × 102 × 102 × 102) = 108 mols. In case of insulin the stimulated receptor molecule activates several molecules of G-proteins, found at the inner surface of the plasma membrane. • These G proteins activate the enzyme (phosphodiesterase) which converts phosphoetidyl-inositol 4,5-biphosphate (PIP2) into Diacylglycerol (DG) and Inositol tri-phosphate (IP3). Both act as IInd messengers. • The IP3 is water soluble and enters into cytoplasm. There it stimulates endoplasmic reticulum for the release of Ca++, the IIIrd messenger, which activates a chain of reactions. • DG, another II-messenger, is insoluble in water and stays in plasma membrane. Here it activates Protein Kinases C, which bring out many metabolic changes in the cytoplasm. The following compounds may act as IInd, and some even III-messengers, in hormonal action : (i) Cyclic Adenosine Monophosphate (cAMP) (ii) Cyclic Guanosine Monophosphate (cGMP) (iii) Diacyl glycerol (DAG or DG) (iv) Inositol triphosphate (ITP or IP3) (v) Calcium (Ca++) Heart muscles use 2-types of II-messengers. The cAMP is the II-messenger for adrenaline and stimulates heart beat. The cGMP is the II-messenger for acetylcholine and slows down the heart beat. •

I.

Connecting Concepts  The G-proteins are so named, because they are bound to GTP (an analogue of ATP). They contain α, β & γ subunits. In the absence of hormones the G-proteins are in the form of inactive GDP.

II.

CHEMICAL COORDINATION AND REGULATION

837

EXERCISE - 1 | NCERT BASED QUESTIONS 1.

2.

3.

4. 5.

6.

7.

8.

9.

10.

Which of the followings is the more scientific definition of hormone? (1) They are extracellular messengers (2) They always act at distantly located target organ (3) They are the products of well organized endocrine glands (4) They are non-nutrient chemicals that act as intercellular messengers Mark the correct statement regarding somatostatin (1) It is secreted from anterior pituitary (2) It inhibits the release of growth hormone (3) It is secreted from posterior pituitary (4) It stimulates STH secretion Gonadotrophins are secreted from (1) Hypothalamus (2) Neurohypophysis (3) Pars distalis of Pituitary (4) None of these Sleep-wake cycle and menstrual cycle are maintained by (1) Progesterone (2) Melatonin (3) Oxytocin (4) MSH What is true about calcitonin (1) It is released from thyroid gland (2) It contains iodine (3) It is released from parathyroid (4) It is an amino acid Alertness, pupillary dilation and piloerection are due to the effect of (1) Melatonin (2) Corticoids (3) Catecholamines (4) Thyroxine Vasopressin, also called ADH, is synthesized by (1) Adenohypophysis (2) Hypothalamus (3) Neurohypophysis (4) Kidney Which statement, regarding PTH, is correct? (1) It is a peptide hormone (2) It stimulates bone resorption (3) It is hypercalcemic hormone (4) All of these Which of the following is not the hormone of anterior pituitary? (1) Prolactin (2) Oxytocin (3) ACTH (4) Growth hormone Cell mediated as well as humoral immunity is provided by (1) PTH (2) Glucocorticoid (3) Thymosin (4) Thiamine

11.

12.

13.

14.

15. 16.

17. 18.

Which hormone interacts with membrane bound receptor and does not normally enter the target cell (1) FSH (2) Estrogen (3) Thyroxin (4) Cortisol Glycogenesis is the result of the hormone of (1) alpha cells of pancreas (2) beta cells of pancreas (3) Thyroid gland (4) Adrenal gland Which of the following is the function of testosterone (1) It stimulates muscular growth and aggressiveness (2) It influences male sexual behaviour (libido) (3) It causes anabolic (synthetic) effect on protein/ carbohydrate metabolism (4) All of these ANF is a peptide hormone and is secrected from (1) Gastrointestinal tract (2) Kidney (3) Post. Pituitary (4) None of these Which hormone acts on exocrine part of pancreas? (1) GIP (2) Insulin (3) Secretin (4) Steapsin The hormone that supports pregnancy and stimulates mammary glands for the formation of alveoli for storing milk, is secreted from (1) Ant. Pituitary (2) Post. Pituitary (3) Graafian follicle (4) Corpus luteum The hormone that suppresses the immune system is (1) Glucagon (2) Thymosin (3) Adrenaline (4) Cortisol Select the correct matching of a hormone, its source and function.

Hormone (1) Vasopressin

Source Posterior pituitary (2) Norepinephrine Adrenal medulla (3) Glucagon

(4) Prolactin

Function Increases loss of water through urine Increases heart beat, rate of respiration and alertness Beta-cells Stimulates of Islets of glycogenolysis langerhans Posterior Regulates growth of Pituitary mammary glands and milk formation in females

838

BIOLOGY

EXERCISE - 2 | Window to Competitive Exams 1.

2.

3.

4.

5.

6.

7. 8.

9.

10.

11.

In hormone a ction, if receptor molecules are removed from target organ, the target organ will [CBSE ‘95] (1) Continue to respond to hormone (2) Not respond to hormone (3) Continue to respond but requires higher concentration (4) Continue to respond butin the opposite way Which gland is often referred in connection with AIDS? [BHU ‘95] (1) Thymus (2) Thyroid (3) Adrenal (4) Pancreas Ovulation in humans is controlled by [AFMC ‘86; BHU ‘96] (1) FSH and LTH (2) FSH and G.H (3) LTH and LH (4) FSH and LH Which of the following diseases is caused by the under secreation of cortisol? [CPMT ‘96] (1) Anaemia (2) Addison’s disease (3) Hyperglycemia (4) Mental illness or retardation The hormone important in the glucose metabolism is produced by: [PCS ‘96] (1) Liver (2) Thyroid (3) Pituitary (4) Pancreas If thyroxine is added in a beaker which has some small tadpoles then: [CPMT ‘96] (1) all tadpoles die (2) they metamorphose very fast (3) they develop small body (4) they develop a giant body Which one opposes parathormone ? [RPMT ‘96] (1) ADH (2) STH (3) Thyroxine (4) Thyrocalcitonin Hormones differ from enzymes in being (1) Found in plants only [CPMT ‘96] (2) Found in animals only (3) Used up in metabolism (4) Not used in metabolism. Abnormal secretion of thyroxine produces [CPMT ‘96] (1) Acromegaly (2) Addison’s disease (3) Cretinism (4) Goitre Which hormone controls growth, mental faculties and tissue differentiation ? [Bihar ‘96] (1) STH (2) Parathormone (3) Thyroxine (4) Cortisone. Release of milk from mother’s breast is mediated through [CBSE ‘96] (1) Prolactin (2) Relaxin (3) Oxytocin (4) Progesterone

12.

13.

14.

15.

16. 17. 18.

19.

20.

21. 22.

Renin is produced by [MP ‘96] (1) Liver (2) Spleen (3) Juxtaglomerular cells (4) Stomach Which of the following is a gastro-intestinal hormone? [AFMC ‘97] (1) Cholinesterase (2) Enterokinase (3) Secretin (4) Interocrinin Find out the correct matching pair from the following: [PCS ‘97] (1) Hyperglycemia .................. Glucagon (2) Calcitonin .................. Parathyroid (3) Vitamin D .................. Cretinism (4) Thyroxine .................. Rickets Hormone that causes the milk ejection from the breasts when the baby begins to suckle is called: (1) Prolactin (2) Oxytocin [PCS ‘97] (3) Progesterone (4) Estrogen Which is a gastro-intestinal hormone? [AFMC ‘97] (1) Ptyalin (2) Enterokinase (3) Cholinesterase (4) Secretin Hormone produced in allergic reactions is [AFMC ‘97] (1) Glucocorticoid (2) Mineralocorticoid (3) Norepinephrine (4) Epinephrine Hormones involved in carbohydrate metabolism are [JIPMER ‘97] (1) Insulin, glucagon, epinephrine and calcitonin (2) Insulin, glucagon, epinephrine and glucocorticoids (3) Insulin, glucagon, cortisol and melatonin (4) Insulin, glucagon, norepinephrine and melatonin A tadpole with surgically removed thyroid gland can be made to metamorphose if [AIIMS ‘85 CPMT ‘97] (1) Given an injection of TSH (2) Given an injection of oxytocin (3) Given an injection of thyroxine (4) Feed on dried thyroid gland. The endocrine gland of insects, which secretes the juvenile hormone, is [AIIMS ‘97] (1) Corpora allata (2) Corpora myecaena (3) Corpora albicans (4) All of these Repair of endometrium is undertaken by (1) LH (2) FSH [AMU ‘97] (3) Oestrogen (4) Prolactin Alloxan treatment destroys [CPMT ‘90, ‘91; AIIMS ‘98] (1) α-Cells of islets of Langerhans (2) Sertoli cells (3) Leydig’s cells (4) β-cells of islets of Langerhans

CHEMICAL COORDINATION AND REGULATION 23.

24.

25.

26.

27.

28.

29. 30.

31.

32.

33.

34.

Immune disease in which body destroys the ill-functioning thyroid is [BHU ‘98] (1) Simmond’s disease (2) Graves disease (3) Hashimoto’s disease (4) Myxoedema Hormone connected with increased rate of glycogenesis, blood pressure and heart beat is [CPMT ‘98] (1) Insulin (2) Glucagen (3) Adrenaline (4) FSH Zona glomerulosa of adrenal cortex is involved in [RPMT ‘98] (1) Water and electrolyte balance (2) Carbohydrate metabolism (3) Peptide hormone secretion (4) All of these Addison’s disease is due to under secretion of [DPMT ‘84, ‘99; CPMT ‘96; JIPMER ‘98] (1) Adrenaline (2) Corticoids (3) ACTH (4) Insulin In human beings, which hormone acts as a milk growth hormone ? [AFMC ‘98] (1) Prolactin (2) Estrogen (3) Progesterone (4) Cortisol Removal of thymus gland in the early life of an experimental mammal will cause [RPMT ‘98] (1) Lack of lymphocytes (2) Lack of antibodies (3) Lack of lymphnodes and lymph vessels (4) Both (1) and (2) ACTH is secreted by [BHU ‘82; KCET ‘99] (1) Adrenal cortex (2) Pituitary (3) Adrenal medulla (4) Thyroid Pineal body develops from [EAMCET ‘95; DPMT ‘99] (1) Dorsal part of diencephalon (2) Ventral part of diencephalons (3) Ventral side of cerebellum (4) Lateral side of cerebrum. The gonadotropic hormone is secreted by [MP ‘95; CBSE ‘99] (1) Posterior lobe of pituitary (2) Cortex of ovary (3) Adenohypophysis (4) Interstitial cells of testis Daily (circadian) rhythms are associated with [CPMT ‘99] (1) Pituitary (2) Thymus (3) Pineal (4) Hypothalamus Which of the following is related to obesity, low plasma Na+, high K+ and increased blood pressure? [CPMT ‘99] (1) Growth hormone (2) Cortisol (3) Thyroxine (4) Adrenaline Restlessness, intolerance to temperature and increased metabolism is due to [JIPMER ‘99] (1) Thyrotoxicosis (2) ACTH deficiency (3) Pituitary deficiency (4) Calcitonin deficiency

839 35. 36.

37.

38.

39.

40.

41.

42. 43.

44.

45.

46.

47.

Disease caused by deficiency of parathormone is [MP ‘99] (1) Osteomalacia (2) Hypercalcemia (3) Tetany (4) Myxoedema Which are identical? [MAHE ‘99] (1) ACTH and adrenaline (2) hCG and progesterone (3) Calcitonin and Oxytocin (4) Vasopressin and ADH. Which hormone promotes cell division, protein synthesis and bone growth? [AFMC ‘99] (1) GH (2) ADH (3) ACTH (4) PTH Oxytocin helps in: [CBSE ‘99] (1) ovulation (2) implantation of the embryo (3) lactation (4) childbirth Which is true of thyrocalcitonin ? [RPMT ‘96; JK 2000] (1) Produced by parathyroid, decreases Ca++ in ECF (2) Produced by thyroid, decreases Ca++ in ECF (3) Produced by parathyroid, increases Ca++ in ECF (4) Produced by thyroid, increases Ca++ in ECF Hormone adrenaline and pigment melanin are formed from [CBSE ‘97; JIPMER 2000] (1) Glycine (2) Tryptophan (3) Tyrosine (4) Proline A woman may develop beard and moustaches due to [MAHE 2000] (1) Hypersecretion of adrenal cortex (2) Hypersecretion of thyroxine (3) Huyposecretion of adrenaline (4) Hyposecretion of thyroxine Hormone produced more in dark is [MP 2000] (1) Thyroxine (2) Melatonin (3) Adrenaline (4) Insulin Gull’s disease is related to deficiency working of [Kerala 2000] (1) Thyroid (2) Parathyroid (3) Adrenal cortex (4) Pituitary Hormones of adrenal cortex are synthesized from [CPMT 2000] (1) Tyrosine (2) Tryptophan (3) Cholesterol (4) Glycoproteins Injection of glucagon will: [MP 2000] (1) cause goitre (2) cause galactosemia (3) cause hypoglycemia (4) increase blood sugar level A person has protruding eyes, tachycardia and higher body temperature. He is suffering from [AIIMS 2000] (1) Cretinism (2) Hyperthyroidism (3) Myxoedema (4) Acromegaly Pituitary gland is crushed and injected in Frog. Frog will [CBSE 2000] (1) Start laying eggs almost immediately (2) Change colour (3) Undergo metamorphosis (4) Die

840 48. 49.

50. 51. 52.

53. 54. 55. 56.

57.

58.

59.

60. 61.

BIOLOGY Hypoglycaemic hormone is [Wardha 2000] (1) Insulin (2) Glucagon (3) Thyroxine (4) Calcitonin Progesterone in the contraceptive pills (1) Prevents ovulation [CBSE 2000] (2) Inhibits estrogen (3) Avoids attachment of fertilized egg to attach to endometrium (4) All above The effect of prolactin hormone is on: [MP ‘01] (1) Liver (2) Pancreas (3) Mammary glands (4) Bones Hormone term was coined by [CPMT ‘90; BVP ‘01] (1) E.H. Starling (2) G.W. Harris (3) E.H. Schally (4) W.M. Bayliss Hormones secreted by adrenal medulla are: [PCS ‘01] (1) steroids (2) proteins (3) catecholamines (4) steroids and catecholamines Enteroendocrine gland is present in: [BCECE ‘01] (1) stomach (2) small intestine (3) oesophagus (4) both (1) and (2) Antiageing hormone is [CPMT ‘01] (1) Thyroxine (2) Melatonin (3) Estrogen (4) Testosterone Which is not secreted by anterior pituitary (1) ADH (2) GH [DPMT ‘01] (3) Prolactin (4) FSH Tadpoles will undergo metamorphosis if they are (1) Fed on Frog eggs [AIIMS ‘01] (2) Provided with suitable environment (3) Injected thyroxine (4) Injected gonadotrophic hormones. Osteoporosis is caused by [AMU ‘01] (1) Ca2+ deficiency (2) Hypersecretion of calcitonin (3) K+ deficiency (4) Hypersecretion of Parathormone Blood glucose level in man is regulated by: (1) insulin [PCS ‘01] (2) adrenaline (3) glucagon and insulin (4) all of the above Substances formed at one place and expressing effect at a distant place are called [UA ‘01] (1) Pheromones (2) Enzymes (3) WBC (4) Hormones. Sella tursica is a depression lodging [Wardha ‘01] (1) Pituitary (2) Pineal (3) Adrenal (4) Thyroid The hormone secretin is produced by [CPMT ‘83; MP ‘02] (1) Pancreas and influences the conversion of glycogen to glucose (2) Pancreas stimulates Isleb of longer lons (3) Testis and produces male secondary sex characters (4) Small intestine and stimulates pancreas.

62.

63.

64.

65.

66.

67. 68.

69.

70.

71.

72.

73. 74.

Choose the correct statement about ‘neurohypophysis’ [Karnataka ‘02] (1) It stores and release hormones secreted by hypothalamus (2) It secretes its own hormones (3) It is poorly developed and functionless in humans (4) It stores the hormones produced by adeno hypophysis Which of the following hormones is cholesterolderivative [PCS ‘02] (1) Estrogen (2) Prostaglandin (3) Epinephrine (4) All of these Which of the following is an example of negative feedback? [PCS ‘02] (1) Sucking reflex (2) Uterine contractions during labour (3) Secretion of CRH in response to ACTH (4) Hair erection due to low body temperature The “biological clock” in higher vertebrates is regulated by: [IAS ‘02] (1) thymus (2) cerebral cortex (3) the pituitary gland (4) supra-chiasmatic nucleus in hypothalamus A hormone that acts upon the renal tubule and blood capillaries is: [St. Johns MC ‘02] (1) glucagon (2) Aldosterone (3) vasopressin (4) glucocorticoids Spermatogenesis is initiated by hormone [BVP ‘02] (1) Testosterone (2) Androgen (3) Prostaglandin (4) FSH Which of the following is second messenger for hormonal action [MP ‘02] (1) ATP (2) cAMP (3) GTP (4) TRF What is true about neurohypophysis [KCET ‘02] (1) It stores hormones produced by adenohypophysis (2) It is vestigial in humans (3) It stores and releases neurohormones (4) Produces neuro hormones Hormone useful in suppressing allergies, rheumatoid arthritis and tissue inflammation is [EAMCET ‘02] (1) Mineralocorticoid (2) Glucocorticoid (3) Thyroxine (4) Adrenaline Which of the following is puberty hormone [St. Johns MC ‘02] (1) GH (2) ACTH (3) Thyroxine (4) Testosterone Insulin is: [St. Johns MC ‘02] (1) glycoprotein (2) diabetic hormone (3) catabolic hormone (4) antidiabetic hormone ‘Brain sand’ is associated to [AMU ‘02] (1) pineal body (2) thymus gland (3) thyroid gland (4) pituitary gland Steroids are precursors of [AMU ‘02] (1) Progesterone (2) Oestrogen (3) Testosterone (4) All above

CHEMICAL COORDINATION AND REGULATION 75.

76. 77.

78.

79.

80. 81. 82.

83.

84.

85. 86.

87.

If both the ovaries of rat are removed which of the following hormones will be deficient ? [CBSE ‘02] (1) Prolactin (2) Oestrogen (3) Oxytocin (4) Gonadotrophic hormone Thyroxin acts on every organ of the body except (1) Adult brain (2) Testis [Punjab ‘02] (3) Thyroid itself (4) Bones Which one secretes fright and flight hormone ? [CET Chd ‘90; KCET 2000; MP ‘02] (1) Pituitary gland (2) Pineal gland (3) Adrenal gland (4) Thyroid gland Ovulation and formation of corpus luteum is controlled by [JIPMER ‘02] (1) ICSH (2) FSH (3) Luteotrophic hormone (4) Luteinizing hormone Hormones may be: [MP ‘91; Pune ‘03] (1) Steroids (2) Peptides (3) Amino acid derivatives (4) All of the above MSH is secreted by: [Jharkhand ‘03] (1) Pars intermedia (2) Pars tuberalis (3) Pars distalis (4) Pars nervosa ACTH is secreted by: [CPMT ‘03] (1) Adrenal medulla (2) Pituitary (3) Thyroid (4) Adrenal cortex Which one is correctly matched [CBSE ‘03] (1) Relaxin - Gigantism (2) Prolactin - Cretinism (3) Parathyroid hormone - Tetany (4) Insulin – Diabetes insipidus A person passes excessive urine and drinks much water but his glucose level is normal. It is due to [AIIMS ‘03] (1) Increased secretion of glucagon (2) Fall in glucose released in urine (3) Reduction in insulin secretion (4) Reduction in vasopressin secretion in posterior pituitary Source of somatostatin is the same as that of (1) Insulin and glucagon [AIIMS ‘03] (2) Vasopressin and oxytocin (3) Thyroxine and calcitonin (4) Somatotropin and prolactin Point out the odd one: [DPMT ‘03] (1) Corticotropin (2) Vasopressin (3) Noradrenaline (4) Prolactin In females, the hormone inhibin is secreted by: [AMU ‘03] (1) theca cells (2) granulosa cells (3) corpus luteum (4) zona pellucida The disease in adult due to the hyperactivity of thyroid gland is called: [MH ‘03] (1) Exophthalmic goitre (2) Gull’s disease (3) Hashimoto’s disease (4) All of these

841 88.

89.

[Punjab ‘03]

Which gland secretes somatostatin? (1) Pineal

(2) Thyroid

(3) PItuitary

(4) Hypothalamus

The target organ of insulin and adrenaline is: [Jharkhand ‘03]

90.

(1) heart

(2) lungs

(3) liver

(4) pancreas

Which of the following endocrine gland is not paired? [Vellore ‘03] (1) gonad

91.

92.

93.

94.

95.

96.

97.

98.

99.

(2) thymus

(3) parathyroid (4) adrenal (supra renal) Which of the following is a neuropeptide hormone? [Jharkhand ‘03] (1) insulin (2) oxytocin (3) Thyroxine (4) glucagon Which of the following hormones is not a secretion product of human placenta? [CBSE ‘04] (1) Prolactin (2) Estrogen (3) Progesterone (4) Human chorionic gonadotropin The hormone that helps in the conversion of glucose to glycogen is: [CBSE ‘04] (1) Insulin (2) Bile acids (2) Cortisone (4) Adrenaline The first hormone artificially produced by genetically engineered bacteria is: [CBSE ‘96; MAHE ‘05] (1) Insulin (2) Somatotropin (3) Testosterone (4) Adrenaline Which endocrine gland stores its secretion in extracellular spaces before discharging it into blood? [CBSE ‘95; Orissa ‘05] (1) Testis (2) Pancreas (3) Thyroid (4) Adrenal Anterior lobe of pituitary secretes: [MP ‘90; BHU ‘05] (1) ACTH, TSH and Oxytocin (2) STH, GH and ADH (3) TSH, ADH and Prolactin (4) FSH,GH and LH Diabetes insipidus is caused by hyposecretion of [CPMT ‘92, ‘94; RPMT ‘98; KCET ‘02; GCET ‘06] (1) Insulin (2) Vasopressin (3) Oxytocin (4) Thymosin FSH and LH are [BHU ‘82; MP ‘97; Haryana ‘05] (1) Emergency hormones (2) Neurohormones (3) Gonadotropin hormones (4) Antistress hormones Hormone whose secretion increases in emotional disturbances or stress [CPMT ‘88; Haryana ‘05] (1) Vasopressin (2) Adrenaline (3) Thyroxine (4) Oxytocin

842

BIOLOGY

100. Secretin and cholecystokinin are digestive hormones. They are secreted in: [CBSE’05] (1) Pyloric stomach (2) Duodenum (3) Ileum (4) Oesophagus 101. Match the list -I with list II [Manipur ‘05]

102.

103.

104.

105.

106.

107.

108.

List - I List -II a. adenohypophysis 1. epinephrine b. adrenal medulla 2. somatotropin c. parathyroid gland 3. thymosin d. thymus gland 4. calcitonin (1) a : 3, b : 1, c : 4, d : 2 (2) a : 1, b : 2, c : 3, d : 4 (3) a : 2, b : 1, c : 4, d : 3 (4) a : 4, b : 3, c : 2, d : 1 A patient of Diabetes mellitus excretes glucose in urine even when he is kept in a carbohydrate free diet. It is because [Orissa ‘05] (1) fats are catabolised to form glucose (2) amino acids are catabolised in liver (3) amino acids are discharged in blood stream from liver (4) glycogen from muscles are released in the blood stream. Hormone which bring about inhibition of gastric secretion in man is [CPMT ‘05] (1) enterokinase (2) enterogastrone (3) enterocrinine (4) cholecystokinin Goitre disorder is due to the deficiency of (1) iron (2) iodine [JK ‘05] (3) protein (4) retinol Which of the following is not paired correctly ? [Kerala ‘05] (1) myxoedema swollen facial tissues (2) cretinism mentally retarded (3) Grave’s disease exophthalmos (4) insulin raise blood glucose Which hormone helps in reabsorption of water from kidney? [Orissa ‘05] (1) ADH (2) STH (3) ACTH (4) TTH If receptor molecule is removed from target organ for hormone action, the target organ will [Manipur ‘05] (1) continue to respond but require higher concentration of hormone (2) continue to respond but in opposite away (3) continue to respond without any difference (4) not respond to hormone Which is a result of ADH deficiency? (1) increase urine output [BCECE ‘05] (2) increased water in urine (3) less urine (4) no urination

109. Vasopressin stimulates reabsorption of water and reduction of urine secretion. Hence vasopressin is otherwise called (1) synovial fluid [Kerala ‘05] (2) neurotransmitter (3) antidiuretic hormone (4) growth regulating substance 110. Identify from the following, a hormone produced by the pituitary gland in both males and females but funcional only in females [KCET ‘05] (1) vasopressin (2) relaxin (3) prolactin (4) somatotropic hormone 111. Hormone responsible for metamorphosis in tadpole is [MAHE ‘05] (1) adrenaline (2) thyroxine (3) aldosterone (4) vasopressin 112. Low level of progesterone and estrogen in blood stimulate [AMU ‘05] (1) FSHRH production (2) LH production (3) GH production (4) all of these 113. Which of the following is gonadotrophic hormone [CPMT ‘05] (1) Collip’s hormone (2) prolactin (3) oxytocin (4) luteinizing hormone 114. Which one of the following four glands is correctly matched with the accompanying description? [AIIMS ‘05] (1) Thyroid - hyperactivity in young children causes cretinism (2) Thymus - starts undergoing atrophy after puberty (3) Parathyroid - secretes parathormone which promotes movement of calcium ions from blood into bones during calcification (4) Pancreas - Delta cells of Islets of Langerhans secrete a hormone which stimulates glycolysis in liver 115. Match item in column A with those given in column B [Kerala ‘05] 1. 2. 3. 4. 5.

Column A ADH ACTH alsosterone insulin adrenaline

A. B. C. D. E.

Column B pituitary mineralocorticoid diabetes mellitus diabetes insipidus vasodilator

(1) 1 - A, 2 - D, 3 - B, 4 - C, 5 - E (2) 1 - D, 2 - B, 3 - A, 4 - C, 5 - E (3) 1 - D, 2 - A, 3 - B, 4 - C, 5 - E (4) 1 - D, 2 - A, 3 - C, 4 - B, 5 - E 116. Placenta produces which hormone [Haryana ‘05] (1) ACTH (2) progesterone (3) GH (4) gastrin 117. A gland which gradually atrophies at the age of 14- 16 due to the activities of sex gland is [Kerala ‘05] (1) thyroid (2) parathyroid (3) pancreas (4) thymus.

CHEMICAL COORDINATION AND REGULATION 118. Choose the correct combination of labelling in the hormonal control of female reproductive system [Kerala ‘05] Hypothalamus

Positive feedback

A Anterior pituitary

Negative feedback

B Ovary

C

D

119.

120.

121. 121. 123.

124.

125.

126.

(1) A- GnRH, B - TSH, C - LTH, D - uterus (2) A - GnRH, B - FSH/LH, C - estrogen or progesterone, D - urerus (3) A - GnRH, B - STH, C - LH, D - uterus (4) A - GnRH, B - ACTH, C - LH, D - uterus Acromegaly is due to the hypersecretion of a hormone from [EAMCET ‘05] (1) Neurohypophysis (2) Adenohypophysis (3) Cells of Leydig (4) Pars intermedialis The hormone that prepares and maintains the uterus, during pregnancy is secreted by : [EAMCET ‘05] (1) Corpora cardiaca (2) Corpus luteum (3) Corpora albicans (4) Graffian follicle Father of endocrinology is [CPMT 2000; BHU ‘06] (1) Bayliss & starling (2) Addison (3) Pasteur (4) Whittaker. The islets of langerhans are found in [BHU ‘06] (1) pancreas (2) stomach (3) liver (4) alimentary canal Sertoli cells are regulated by the pituitary hormone known as [CBSE ‘06] (1) GH (2) Prolactin (3) LH (4) FSH A steroid hormone which regulates glucose metabolism is [CBSE ‘06] (1) Corticosterone (2) 11- deoxycorticosterone (3) Cortisone (4) Cortisol Which one of the following is not a second messenger in hormone action ? [CBSE ‘06] (1) Calcium (2) Sodium (3) cAMP (4) cGMP Which of the following is an accumulation and release centre of neurohormones ? [CBSE ‘06] (1) Intermediate lobe of the pituitary (2) Hypothalamus (3) Anterior pituitary lobe (4) Posterior pituitary lobe

843 127. Which hormone causes dilation of blood vessels, increased oxygen consumption and glucogenesis ? [CBSE ‘06] (1) Insulin (2) Adrenalin (3) Glucagon (4) ACTH 128. Which one of the following statement is correct? [CBSE ‘06] (1) Endrocrine glands regulate neural activity, and nervous system regulates endocrine glands (2) Neither hormones control neural activity nor the neurons control endocrine activity (3) Endocrine glands regulate neural activity, but not vice versa (4) Neurons regulate endocrine acticity, but not vice versa 129. Column I lists the endocrine structure and column II lists the corresponding hormones. Match the two columns. Identify the correct option from those given [KCET’06] Column I A. B. C. D.

130.

131.

132.

133.

134. 135.

136.

hypothalamus anterior pituitary testis ovary

Column II p. q. r. s. t.

relaxin estrogen FSH and LH testosterone gonadotropin releasing hormone (1) A = t, B = r, C = s, D = q (2) A = t, B = r, C = q, D = s (3) A = p, B = q, C = s, d = r (4) A = r, B = t, C = s, D = q. In the homeostatic control of blood sugar level, which organs function respectively as modulator and effector? [KCET ‘06] (1) liver and islets of langerhans (2) hypothalamus and liver (3) hypothalamus and islets of langerhans (4) islets of langerhans and hypothalamus Which of the following hormones are produced in the hypothalamus and stored in the posterior pituitary? [KCET ‘06] (1) FSH and LH (2) ADH and oxytocin (3) TSH and STH (4) ACTH and MSH Secretion of which of the following structure is preparing inner wall of uterus of implantation [GCET ‘06] (1) ovary (2) pituitary gland (3) corpus luteum (4) ovarian follicle During emergency which of the following hormone is secreted? [BHU ‘06] (1) aldosterone (2) thyroxine (3) adrenaline (4) calcitonin LH and FSH are collectively called [BHU’06] (1) oxytocin (2) somatotrophins (3) luteotrophic (4) gonadotrophins Parathyroid [AMU’06] (1) increases blood Ca level (2) decreases blood Ca level (3) promotes collagen synthesis by osteoblasts (4) all of the above Which is not a symptom of hypothyroiditis? [AMU’06] (1) lethargy (2) mental retardation (3) oedema (4) rise in blood urea

844 137. Which is responsible for sleep cycle movement? (1) dopamine (2) melatonin [AMU’06] (3) serotonin (4) adrenaline 138. In human testosterone is produced by (1) tunica albuginea [HPMT’06] (2) Leydig cell (3) seminiferous tubule (4) sertoli cell 139. Insulin is secreted by [HPMT’06] (1) α -cell of islets of langerhans (2) δ-cell of islets of langerhans (3) β-cell of islets of langerhans (4) pancreatic acinus cell 140. ADH, responsible for reabsorption of water and reduction of urine secretion, is synthesized by (1) posterior pituitary gland [HPMT’06] (2) juxtaglomerular apparatus (3) hypothalamus (4) anterior pituitary gland 141. The excessive secretion of mineralocorticoids, independent of renin-angiotensin-aldosterone system, results in [JK’06] (1) Cushing’s syndrome (2) Conn’s syndrome (3) Addison’s disease (4) Grave’s disease 142. The first protein to have its primary structure determined was [HPMT’06] (1) urease (2) insulin (3) glucagon (4) histone H1 143. The lorain-levi syndrome is due to [JK’06] (1) hyper functioning of pituitary (2) hypothyroidism (3) hyperthyroidism (4) deficiency of growth hormone 144. Steroid hormones transmit their information by [CPMT’06] (1) stimulating the receptors present on cell membrance (2) entering into the cell and modifying cellular contents (3) entering into the cell and modifying nuclear organization (4) the help of an intracellular second messenger 145. The hormones that initiate ejection of milk, stimulates milk production and growth of ovarian follicles, are respectively known as [Kerala’06] (1) PRL, OT and LH (2) OT, PRL and FSH (3) LH, PRL and FSH (4) PRH, OT and LH 146. Match the hormone in column I with their function in column II. [Kerala’06]

BIOLOGY

a.

Column I FSH

b. LH c. progesterone d. estrogen

147.

148.

149.

150.

151.

152.

153.

154.

155.

Column II 1. prepare endometrium for implantation 2. develops female secondary sexual characters 3. contraction of uterine wall 4. development of corpus luteum 5. maturation of graafian follicle

(1) a–5, b–4, c–1, d–2 (2) a–4, b–5, c–2, d–1 (3) a–4, b–3, c–2, d–5 (4) a–5, b–1, c–2, d–4 Which one of the following endocrine gland functions as a biological clock and a neurosecretory transducer? [Kerala’06] (1) adrenal gland (2) thyroid gland (3) pineal gland (4) thymus gland Hypothyroidism in adults and hyperparathyroidism in children will respectively lead to [Kerala’06] (1) myxoedema and cretinism (2) Grave’s disease and Hashimoto’s disease (3) Myxoedema and osteitis fibrosa cystica (4) Addison’a disease and cretinism In heart cells, which one serves as a second messenger, speeding up muscle cell contraction in response to adrenaline? [Kerala’06] (1) cAMP (2) cGMP (3) GTP (4) ATP Feeling the tremors of an earthquake a scared resident of seventh floor of a multistoryed building starts climbing down the stairs rapidly. Which hormone initiated this action? [CBSE’07] (1) Gastrin (2) Thyroxin (3) Adrenaline (4) Glucagon Which part of ovary in mammals acts as an endocrine gland after ovulation? [CBSE’07] (1) Vitelline membrane (2) Graffian follicle (3) Stroma (4) Germinal epithelium A person is having problems with calcium and phosphorus metabolism in his body. Which one of the following glands may not be functioning properly? [CBSE’07] (1) Thyroid (2) Parathyroid (3) Parotid (4) Pancreas Which one of the following is an amine hormone? [CBSE ‘08] (1) Progesterone (2) Thyroxine (3) Oxypurin (4) Insulin The blood calcium level is lowered by deficiency of: (1) Calcitionin [CBSE ‘08 ] (2) Parathormone (3) Thyroxine (4) Both calcitonin and parathormone Human insulin is being commercially produced from a transgenic species of: [CBSE ‘08] (1) Saccharomyces (2) Escherichia (3) Mycobacterium (4) Rhizobium

CHEMICAL COORDINATION AND REGULATION 156. Which one of the following pairs of organs includes only the endocrine glands? [CBSE ‘08] (1) Adrenal and Ovary (2) Parathyroid and Adrenal (3) Pancreas and Parathyroid (4) Thymus and Testes 157. A health disorder that results from the deficiency of thyroxine in adults and characterised by (i) a low metabolicrate, (ii) increase in body weight and (iii) tendency to retain water in tissues is: [CBSE ‘09] (1) cretinism (2) hypothyroidism (3) simple goitre (4) myxoedema 158. Which of the following hormones contains iodine? (1) thyroxine (2) insulin [CBSE ‘09] (3) testosterone (4) adrenaline 159. Which one of the following pairs is incorrectly matched? (1) Insulin–Diabetes mellitus (disease) [CBSE ‘10] (2) Glucagon–Beta cells (source) (3) Somatostatin–Delta cells (source) (4) Corpus luteum–Relaxin (secretion) 160. Toxic agents present in food which interfere with thyroxine synthesis lead to the development of: [CBSE ‘10] (1) thyrotoxicosis (2) toxic goitre (3) cretinism (4) simple goitre 161. Injury to adrenal cortex is not likely to affect the secretion of which one of the following? [CBSE ‘10] (1) Cortisol (2) Aldosterone (3) Both Androstenedione and Dehydroepiandro sterone (4) Adrenaline 162. Low Ca+ + in the body fluid may be the cause of: (1) Gout (2) Tetany [CBSE ‘10] (3) Anaemia (4) Angina pectoris 163. Match the source gland with its respective hormone as well as the function [CBSE’ 11] Source gland

Hormone

Function

1.

Thyroid

Thyroxine

Regulates blood calcium level

2.

Anterior pituitary

Oxytocin

Contraction of uterus muscles during child birth

3.

Posterior pituitary

Vasopressin

Stimulates resorption of water in the distal tubules in the nephron

4.

Corpus luteum

Estrogen

Supports pregnancy

164. Given below is an incomplete table about certain hormones, their source glands and one major effect of each on the body in humans. Identify the correct option for the three blanks A, B and C [CBSE’ 11] GLANDS A Alpha cells of Islets of Langerhans Anterior pituitary

SECRETION EFFECT ON BODY Oestrogen B C

Maintenance of secondary sexual characters Raises blood sugar level Over secretion leads to Gigantism

845 Options: (1) (2) (3) (4)

A Placenta Ovary Placenta Ovary

B Glucagon Glucagon Insulin Insulin

C Calcitonin Growth hormone Vasopressin Calcitonin

165. Somatostatin [DPMT’ 11] (1) Stimulates glucagon release while inhibits insulin release (2) Stimulates release of insulin and glucagon (3) Inhibits release of insulin and glucagon (4) Inhibits glucagon release while stimulates insulin release 166. Corpus luteum releases [DPMT’ 11] (1) Estrogen (2) Progesterone (3) Estrogen and progesterone (4) Androgen 167. Insufficient quantities of antidiuretic hormone in blood lead to [DPMT’ 11] (1) Diabetes mellitus (2) Glycosuria (3) Diabetes insipidus (4) Uremia 168. Thymosin hormone is secreted by [DPMT’ 11] (1) Thyroid gland (2) Parathyroid gland (3) Thymus gland (4) Hypothalamus 169. Which of the following is a minerelocorticoid? [WB JEE’ 11] (1) Calciferol (2) Progesterone (3) Adrenalin (4) Aldosterone 170. Which one of the following is not a second messenger in hormone action? [WB JEE’ 11] (1) Calcium (2) Sodium (3) cAMP (4) cGMP 171. Calcium level decreases in the blood due to hyposecretion of [WB JEE’ 11] (1) Parathyroid hormone (2) Calcitonin (3) Thyroxine (4) Adrenaline 172. Tetany is caused by [WB JEE’ 11] (1) Hyperparathyroidism (2) Hypoparathyroidism (3) Hyperthyroidism (4) Hypothyroidism 173. Name the hormone that has no role in menstruation. (1) LH (2) FSH [WB JEE’ 11] (3) GH (4) TSH 174. The 24 hour (diurnal) rhythm of our body such as the sleep-wake cycle is regulated by the hormone. [CBSE Final’ 11] (1) Adrenaline (2) Melatonin (3) Calcitonin (4) Prolactin 175. Which one of the following pairs of hormones are the examples of those that can easily pass through the cell membrane of the target cell and bind to a receptor inside it (mostly in the nucleus) [CBSE’ 12] (1) Somatostatin, oxytocin(2) Cortisol, testosterone (3) Insulin, glucagon (4) Thyroxin, Insulin

846

BIOLOGY

176. The Leydig cells as found in the human body are the secretory source of [CBSE’ 12] (1) Glucagon (2) Androgens (3) Progesterone (4) Intestinal mucus 177. What is correct to say about the hormone action in humans? [CBSE’ 12] (1) In females, FSH first binds with specific receptors on ovarian cell membrane (2) FSH stimulates the secretion of estrogen and progesterone (3) Glucagon is secreted by β-cells of Islets of langerhans and stimulates glycogenolysis (4) Secretion of thymosins is stimulated with aging 178. In a normal pregnant woman, the amount of total gonadotropin activity was assessed. The result expected was [CBSE’ 12] (1) High levels of FSH and LH in uterus to stimulate endometrial thickening (2) High level of circulating HCG to stimulate estrogen and progesterone synthesis (3) High level of circulating FSH and LH in the uterus to stimulate implantation of the embryo (4) High level of circulating HCG to stimulate endometrial thickening 179. A pregnant female delivers a baby who suffers from stunted growth, mental retardation, low intelligence quotient and abnormal skin. This is the result of [AIPMT (NEET)’13] (1) Deficiency of iodine in the diet (2) Low secretion of growth hormone (3) Cancer of thyroid gland (4) Over secretion of pars distalis 180. Which of the following statements is correct in relation to the endocrine system? [AIPMT (NEET)’13] (1) Adenohypophysis is under direct neural regulation of the hypothalamus (2) Organs in the body like gastrointestinal tract, heart, kidney and lover do not produce any hormones (3) Non- nutrient chemicals produced by the body in trace amount that act as intercellular messenger are known as hormones (4) Releasing and inhibitory hormones are produced by the pituitary gland 181. Select the answer which correctly matches the endocrine gland with the hormone it secretes and its function/ deficiency [AIPMT (NEET)’13] Endocrine gland

Hormone

Function/deficiency symptoms

(1)

Anterior pitu- Oxytocin itary

Stimulates uterus contraction during child birth

(2)

Posterior pitu- G r o w t h h o r itary mone

Oversecretion stimulates abnormal growth

(3)

Thyroid gland

Thyroxin

Lack of iodine in diet results in goitre

(4)

Corpus luteum

Testosterone

Stimulates spermatogenesis

182. The following is not the function of progesterone: (1) Gestation [AMU’13] (2) Inhibition of ovulation (3) Uterine growth and development (4) Stimulation of mammary secretion 183. GnRH secreted from hypothalamus mainly stimulates the release of: [AMU’13] (1) Thyroxin from thyroid gland (2) ADH from posterior pituitary (3) FSH and LH from anterior pituitary (4) Aldosterone from adrenals 184. The 51 amino acids of insulin are arranged in:[AMU’14] (1) Single polypeptide (2) Two polypeptide having 21 and 30 amino acids (3) Two polypeptide having 25 and 26 amino acids (4) Two polypeptide having 18 and 33 amino acids 185. Identify the hormone with its correct matching of source and function: [AIPMT’14] (1) Oxytocin- posterior pituitary, growth and maintenance of mammary glands (2) Melatonin- pineal gland, regulates the normal rhythm of sleep wake cycle (3) Progesterone- corpus luteum, stimulation of growth and activities of female secondary sex organs (4) Atrial natriuretic factor- ventricular wall, increases the blood pressure 186. Fight or flight reactions cause activation of:[AIPMT’14] (1) The parathyroid glands, leading to increased metabolic rate (2) The kidney, leading to suppression of reninangiotensin- aldosterone pathway (3) The adrenal medulla, leading to increased secretion of epinephrine and nor- epinephrine (4) The pancreas leading to a reduction in the blood sugar levels 187. Select the correct option describing gonadotropin activity in a normal pregnant female: [AIPMT’14] (1) High level of FSH and LH stimulate the thickening of endometrium (2) High level of FSH and LH facilitate implantation of the embryo (3) High level of hCG stimulates the synthesis of estrogen and progesterone (4) High level of hCG stimulates the thickening of endometrium 188. A chemical signal that has both endocrine and neural role, is: [AIPMT’15] (1) Melatonin (2) Calcitonin (3) Epinephrine (4) Cortisol 189. Which one of the following hormones is not involved in sugar metabolism? [RE-TEST AIPMT’15] (1) Aldosterone (2) Insulin (3) Glucagon (4) Cortisone

CHEMICAL COORDINATION AND REGULATION 190. Which one of the following hormones though synthesized elsewhere, is stored and released by the master gland? [RE-TEST AIPMT’15] (1) Luteinizing hormone (2) Prolactin (3) Melanocyte stimulating hormone (4) Antidiuretic hormone 191. Which one of the following hormone is not a glycoprotein? [UP CPMT’15] (1) FSH (2) TSH (3) LH (4) ACTH 192. Addison’s disease is caused due to: [UP CPMT’15] (1) Hypersecretion of Adrenal cortex (2) Hyposecretion of Adrenal cortex (3) Hypersecretion of Leydig cells (4) Hypersecretion of thyroid 193. The amount of which hormone is increased during fear? [UP CPMT’15] (1) Insulin (2) Adrenalin (3) Glucagon (4) Aldosterone 194. Diabetes insipidus is caused due to deficiency of: [UP CPMT’15] (1) Insulin (2) Glucagon (3) Renin (4) ADH 195. The following hormone is not a steroid: [AMU’15] (1) Testosterone (2) Progesterone (3) Corticosteroid (4) Adrenocorticotrophic hormone 196. Tetraiodothyronine refers to: [AMU’15] (1) T3 (2) Thyroxine (3) TSH (4) TRH 197. Secretion of which of the following hormones is not pituitary dependent? [AMU’15] (1) Tridothyronine (2) Testosterone (3) Glucocorticoids (4) Parathyroid hormone 198. The hormones that are produced in women only during pregnancy: [AMU’15]

847

199.

200.

201.

202.

(1) Estrogens, Human chorionic gonadotropins (2) Estrogen, Progesterone, Oxytocin (3) Human placental lactogen, Human chorionic gonadotropin, relaxin (4) Human placental lactogen, Human chorionic gonadotropin, Thyroxine The condition in which the kidneys fail to conserve water leading to water loss and dehydration due to impaired ADH synthesis or release is: [KERALA’15] (1) Grave’s disease (2) Addison’s disease (3) Diabetes insipidus (4) Cretinism The pars distalis region of pituitary does not produce these hormones: [KERALA’15] A. Melanocyte stimulating hormone, B. Vasopressin, C. Prolactin, D. Growth hormone (1) C only (2) A and D (3) B and D (4) A and B Function of the somatostatin is to: [KERALA’15] (1) Stimulate pituitary synthesis and release gonadotropins (2) Inhibit the release of gonadotropins from pituitary (3) Stimulate pituitary and promotes the secretion of growth hormone (4) Inhibit the release of growth hormone from the pituitary Identify the wrongly labelled part: [KERALA’15]

(1) Primary follicle (3) Graafian follicle

(2) Ovum (4) Corpus luteum

848

BIOLOGY

EXERCISE - 3 | Test Yourself 1.

2.

3. 4. 5.

6. 7. 8.

9. 10.

11.

12.

13.

The Chemical messengers which are released out side the body to alter the functioning of other members of the same species are called (1) Parahormones (2) Pheromones (3) Hormones (4) All of these Which of the following is not the hormone of anterior lobe of Pituitary gland (1) ACTH (2) LTH (3) ICSH (4) PTH The disease not associated with Pituitary gland is (1) Acromegaly (2) Simmond’s disease (3) Diabetes insipidus (4) Cretinism Corpus Luteum secretes (1) Lueteotropic hormone (2) Luteinizing hormone (3) Birth hormone (4) Pregnancy hormone Which of the following hormone is called hypercalcimic factor? (1) Aldosterone (2) Calcitonin (3) Collip’s hormone (4) Glucagon On the basis of chemical nature, mark the odd one out (1) Insulin (2) Parathormone (3) Thyroxine (4) Growth hormone Which of the following hormone is lipid soluble? (1) Catecholamine (2) Insulin (3) Thyroxine (4) All of these ICSH stimulates(1) Parafollicular cells or (C-cells) (2) Leydig cells (3) Graafian follicles (4) Islets of Langerhans Insulin deficiency causes (1) Hyperglycemia (2) Glycosuria (3) Diabetes mellitus (4) All of these Which of the following serves as a second messenger for slowing contraction of the heart muscles in response to acetylcholine (1) c AMP (2) c GMP (3) DG (Diacylglycerol) (4) Inositol triphosphate Which amimo acid is helpful in synthesis of Epinephrine hormone (1) Valine (2) Proline (3) Tyrosine (4) Alanine Which one of the following changes does not produce polyuria : (1) Diabetes mellitus (2) Glycosuria (3) Aldosterone injection (4) Diabetes insipidus The secretion of which of the following hormone is related with Renin-angiontensin pathway (1) Erythropoietin (2) Aldosterone (3) Adrenaline (4) CCK

14.

15.

16.

17. 18. 19.

20. 21. 22. 23.

24.

25.

Both adrenaline and cortisol are secreted in response to stress. Which of the following statement is also true for both of these hormones? (1) They are secreted by adrenal cortex (2) They act to increase blood sugar (3) Their secretion is stimulated by adrenocorticotropins (4) All of these Contraceptive pills contain synthetic analogoue of the following hormones (1) Estrogen and Progesteron (2) FSH and LH (3) FSH and estrogen (4) LH and prolactin On hypophysectomy there is fall in sodium level. This is because of (1) Oxytocin is no longer available (2) Adrenal cortex is atrophied (3) GH is not secreted (4) Adrenal medulla is atrophied After menopause the following hormone is excreted in urine (1) FSH (2) LTH (3) Estrogen (4) Relaxin Aldosterone is secreted from following part of adrenal gland (1) Adrenal medulla (2) Zona glomerulosa (3) Zona fasciculata (4) Zona reticularis Which of the following hormone is known as ‘milk let- down factor’? (1) Prolactin (2) Mammotropin (3) Estrogen (4) Oxytocin Which does not have an endocrine function? (1) Pineal body (2) Parotid gland (3) Pancreas (4) Kidney Hyposecretion of thyroxine causes (1) Simple goitre (2) Exophthalmic goiter (3) Myxoedema (4) Dwarfism Which endocrine gland is called ‘the Throne of immunity’? (1) Spleen (2) Thymus (3) Pineal (4) Adrenal medulla All of the following endocrines are enlarged during pregnancy except : (1) Thyroid (2) Thymus (3) parathyroid (4) Adrenal cortex Which of the following statements about calcitonin is false (1) It reduces the number and activity of osteoclasts (2) It reduces the renal tubular absorption of calcium (3) It reduces the renal tubular absorption fo phosphate (4) When present in excess, it commonly causes tetany After four months of pregnancy if the ovaries are removed (1) It will cause abortion (2) The foetus will be mentally retarded (3) There will be no effect on foetus (4) The physical development of the foetus will be affected

CHEMICAL COORDINATION AND REGULATION 26.

27. 28.

29.

30.

31. 32. 33.

34.

35.

36.

Mark the correct matching of hormone and the disorder (1) Parathormone - Cretinism (2) Thyroxine – Ricket (3) Insulin - Diabetes insipidus (4) Cortisol- Cushing’s disease Excess of aldosterone causes (1) Addison’s disease (2) Conn’s syndrome (3) Simmond’s disease(4) Gynecomastisia The receptor for insulin hormone is a tetramer protein having 4- subunits, 2- α units and 2-β units. Which of the following statement regarding this receptor is correct? (1) 2-α subunits protrude out from the surface of the cell and 2-β subunits protrude into the cytoplasm (2) 2-β subunits protrude out from the surface of the cell and 2-α subunits protrude into the cytoplasm (3) One α and one β subunits protrude out from surface of the cell and One α and one β subunits protrude into the cytoplasm (4) All 4- subunits protrude out from the surface of the cells to bind insulin Mark the incorrect statement (1) Failure of the testosterone secretion results in eunuchoidism (2) Enzyme secretion in pancreas is stimulated by CCK hormone (3) Castration changes an aggressive ox into a docile bull (4) HCG is secreted from the ovary Mark the correct statement (1) Hormonal action is less specific than nerve action (2) Hypophysis is the endocrine part of the brain (3) Transmission of information in case of hormones is faster than nerve impulse (4) None of these Which endocrine gland is lodged in the skull? (1) Thymus (2) Thyroid (3) Pineal (4) Mammillary body Which hormone of anterior lobe of pituitary is non-tropic? (1) F.S.H. (2) Prolactin (3) S.T.H. (4) Vasopressin Epinephrine does not (1) Reduce Blood-Clotting time (2) Inhibit peristalsis (3) Promote salivation (4) Increase RBC Count From origin point of view the pituitary gland of human is similar to (1) Thyroid (2) Adrenal medulla (3) Gonads (4) None of these Destruction of anterior lobe of pituitary gland is characterised by all except (1) Infertility (2) Increases immunity (3) Decreased B.M. R. (4) Passage of large volume of urine Removal of thyroid gland leads to (1) High blood cholesterol level (2) Mental ddullness

849

37. 38.

39.

40.

41.

42.

43.

44. 45. 46.

47.

48. 49.

(3) Decrease in blood glucose level (4) All the above Which of the following vitamin acts as a steroid hormone? (1) Vitamin C (2) Vitamin B2 (3) Vitamin D3 (4) Vitamin A1 STH (Growth Hormone) (A) differs from insulin (B) in following action (1) A causes glycogenesis but B causes glycolysis (2) A causes lipolysis but B causes lipogenesis (3) A is catabolic for protein but B is anabolic (4) A causes glycogenolysis but B causes glycogenesis Female intersexes develop when foetus is exposed to copious (plentiful) supply of (1) Estrogen from adrenal (2) Estrogen from ovary (3) Androgen from Testes (4) Androgen from Adrenal Synthesis of collagen fibres at the site of inflammation is reduced in the presence of following hormone (1) STH (2) Cortisol (3) Thymosin (4) None of these Sporadic goitre is endemic in sloppy hills. It is because of (1) Hyposecretion of thyroxine (2) Hypersecretion of thyroxine (3) Hyposecretion of TSH (4) None of these Median eminence and pars tuberalis in pituitary gland are the parts of (1) Neurohypophysis (2) Adenohypophysis (3) Neuro and Adenohypophysis respectively (4) Adeno and Neurohypophysis respectively Which thyroid- hormone is not stored as colloidal material in the thyroid follicles (1) Calcitonin (2) Thyroxine (3) Tri-idothyronine (4) Aldosterone Which hormone acts as a mild growth hormone? (1) Estrogen (2) Prolactin (3) Cortisol (4) Thyroxine The bronzing of skin is the symptom of (1) Addison’s disease (2) Myxoedema (3) Acromegaly (4) None of these Which hormone promotes the descent of testes into the scrotum? (1) F.S.H. (2) Testosterone (3) I.C.S.H. (4) Oxytocin In diabetic ketosis, there is decreased metabolic breakdown of (1) Fat (2) Protein (3) Glucose (4) Glycogen in liver Which subsance is not formed in tryptophan metabolism (1) Melatonin (2) Dopamine (3) Serotonin (4) All of these The receptors for following hormone are present inside the nucleus (1) Epinephrine (2) Cortisol (3) Both (1) and (2) (4) Thyroxine

850 50.

BIOLOGY Mark the correct matching of tthe he hormone and the endocrine cells I. II. III. IV.

51. 52.

53. 54.

55. 56.

57.

58.

59.

60.

C-Cell β-cell Leydig cell Sertoli cells

A B

Inhibin Calcitonin

C D

Insulin Testosterone

(1) I-A, II-C, III-D, IV-B (2) I-C, II-B, III-D, IV-A (3) I-A, II-C, III-B, IV-D (4) I-B, II-C, III-D, IV-A Removal of parathyroid gland leads to (1) Osteoporosis (2) Acromegaly (3) Tetany (4) Osteomalacia Melatonin hormone is derived from the following amino acid (1) Tyrosine (2) Tryptophan (3) Histidine (4) None of these Consumption of alcohol suppresses the secretion of (1) Insulin (2) Vasopressin (3) Thyroxine (4) Oxytocin STH (Growth hormone) acts on the organs through somatomedin which is secreted mainly from (1) Thymus (2) Liver (3) Kidney (4) Hypothalamus CCK is secreted from (1) Pancreas (2) Gall Bladder (3) Duodenum (4) None of these Chorionic gonadotropin hormone is similar in function to the following hormone (1) FSH (2) Progesteron (3) Mammotropin (4) L.H. Pot-bellied and pigeon-chested with protruded tongue are the symptoms of the following disease (1) Cretinism (2) Grave’s disease (3) Cushing’s syndrome (4) Simmond’s disease The growth hormone in cockroach is secreted from (1) Pituitary gland (2) Prothoracic gland (3) Corpora allata (4) Mushroom gland or uricose gland When the B.P. is high and over loading of heart is present then which hormone is released for compensating this mechanism : (1) Aldosterone (2) A.D.H (3) Atri-natriuretic factor (4) Renin Which hormone of anterior pituitary is inhibited by dopamine (1) Growth hormone (2) Prolactin (3) Gonadotropic hormone (4) Thyroid stimulating hormone

61.

62.

63.

64. 65. 66. 67.

68.

69.

70. 71.

72.

A young boy has infantile penis, seminal vesicle and prostate gland. The condition can be improved by treating with (1) An extract of anterior pituitary (2) Growth hormone (3) Viagra (sidenaphil nitrate) (4) Testosterone A tumour of adrenal cortex produces (1) Cushing’s syndrome (2) Addison’s disease (3) Tetany (4) Grave’s disease Which of the following hormone utilizes cAMP as a second messenger? (1) Aldosterone (2) Estrogen (3) Adrenaline (4) Thyroxine Which of the followings is known as maternity hormone? (1) Progesterone (2) Prolactin (3) Oxytocin (4) Relaxin Hassel’s corpuscles are the macrophages present in (1) Pineal body (2) Pancreas (3) Thymus (4) Adrenal cortex The confusion technique involves the use of the following (1) Juvenile hormone (2) Ecdysone (3) Adrenaline (4) Pheromone Which of the following corticoid hormone is associated with osmoregulation? (1) Aldosterone (2) ADH (3) Both (1) and (2) (4) Thyroxine The hormone ANP (atrial natriuretic peptide) (1) Stimulates the secretion of ADH and Aldosterone (2) Inhibits the secretion of Aldosterone but stimulates ADH secretion (3) Stimulates the secretion of Renin (4) Inhibits the secretion of ADH, Aldosterone and Renin ‘Osteitis fibrosa cystica’ develops due to (1) Hyperparathyroidism (2) Hypothyroidism (3) Hyperthyroidism (4) Hypoparathyroidism The pheromones are derivative of (1) Amino acids (2) Cholesterol (3) Fatty acids (4) Glucose Which of the following hormones stimulates epithelium lining of the crop of both male and female birds for the secretion of ‘pigeon milk’? (1) Estrogen (2) Prolactin (3) Thymosin (4) Growth hormone Sweating, irritability and blurred vision are the symptoms of (1) Hyperglycemia (2) Hypoglycemia (3) Hyposecretion of insulin (4) Both (1) and (3)

CHEMICAL COORDINATION AND REGULATION

851

ANSWER KEY EXERCISE 1 : NCERT BASED QUESTIONS 1. 6. 11. 16.

(4) (3) (1) (4)

2. 7. 12. 17.

(2) (2) (2) (4)

3. 8. 13. 18.

(3) (4) (4) (2)

4. 9. 14.

(2) (2) (4)

5. 10. 15.

(1) (3) (3)

EXERCISE 2 : WINDOW TO COMPETITIVE EXAMS

166. (3)

167. (3)

168. (3)

169. (4)

170. (2)

171. (1)

172. (2)

173. (3)

174. (2)

175. (2)

176. (2)

177. (1)

178. (2)

179. (1)

180. (3)

181. (3)

182. (4)

183. (3)

184. (2)

185. (2)

186. (3)

187. (3)

188. (3)

189. (1)

190. (2)

191. (2)

192. (4)

193. (1)

194. (4)

195. (2)

198. (2)

199. (1)

200. (4)

1.

(2)

2.

(1)

3.

(4)

4.

(2)

5.

(4)

196. (3)

197. (3)

6.

(2)

7.

(4)

8.

(3)

9.

(3)

10.

(3)

201. (2)

202. (3)

11.

(3)

12.

(3)

13.

(3)

14.

(1)

15.

(2)

16.

(4)

17.

(1)

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(2)

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(3)

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(1)

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(3)

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(4)

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(3)

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(3)

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(1)

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(1)

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(4)

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(2)

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(1)

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(3)

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(2)

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(1)

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(1)

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(2)

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(1)

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(1)

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(2)

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(2)

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(1)

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(4)

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(3)

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(1)

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(3)

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(4)

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(2)

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(1)

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(3)

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(1)

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(1)

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(1)

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(1)

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(1)

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(1)

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(1)

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(1)

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(1)

95.

(3)

96.

(4)

97.

(2)

98.

(3)

99.

(2)

100. (2)

EXERCISE 3 : TEST YOURSELF 1.

(2)

Pheromones are also known as ectohormones.

2.

(4)

PTH is parathyroid hormone.

3.

(4)

Cretinism is associated to thyroid gland.

4.

(4)

Birth hormone is known as Oxytocin, while pregnancy hormone is called progesterone.

5.

(3)

Collip’s hormone is common name for PTH.

6.

(3)

Thyroxine is an Amino acid derivative while the rest three are peptides/proteins.

7.

(3)

Thyroxine or steroid hormones are lipid soluble and can pass through cell membrane.

8.

(2)

The Leydig cells are also known as interstitial cells.

9.

(4)

Insulin increases the amount of glucose in blood, which may pass through urine also.

10.

(2)

Diacylglycerol and Inositol triphosphate act as a second messenger for insulin hormone.

11.

(3)

Thyroxine is also synthesized from Tyrosine (amino acid).

12.

(3)

The injection of aldosterone will raise sodium (Na+) level of blood and hence more water absorption, and less urine formation.

13.

(2)

Aldosterone secretion is stimulated by angiontensin II.

101. (3)

102. (1)

103. (2)

104. (2)

105. (4)

106. (1)

107. (4)

108. (2)

109. (3)

110. (3)

111.

(2)

112. (1)

113. (4)

114. (2)

115. (3)

116.

(2)

117. (4)

118. (2)

119. (2)

120. (2)

14.

(2)

Adrenaline is secreted from adrenal medulla.

121. (2)

122. (1)

123. (4)

124. (4)

125. (2)

15.

(1)

Contraceptive pills prevent ovulation

126. (4)

127. (2)

128. (1)

129. (1)

130. (3)

16.

(2)

Aldosterone absorbs sodium from glomerular filtrate.

131. (2)

132. (3)

133. (3)

134. (4)

135. (1)

17.

(1)

136. (4)

137. (2)

138. (2)

139. (3)

140. (3)

The amount of estrogen is not enough to regulate FSH by feed back mechanism.

141. (2)

142. (2)

143. (4)

144. (4)

145. (2)

18.

(2)

146. (1)

147. (3)

148. (3)

149. (1)

150. (3)

Zona glomerulosa is the outer most part of the adrenal cortex.

151. (2)

152. (2)

153. (3)

154. (2)

155. (2)

19.

(4)

Oxytocin stimulates the release of milk.

156. (2)

157. (4)

158. (1)

159. (2)

160. (4)

20.

(2)

161. (4)

162. (2)

163. (3)

164. (2)

165. (3)

Parotid is the Salivary gland. Erythropoietin (hormone) is secreted from kidney.

21.

(3)

Simple goitre is caused by the deficiency of Iodine.

852

BIOLOGY

22.

(2)

Thymus stimulates T-cells which regulate the production of antibodies.

51.

(3)

23.

(2)

24.

25.

(3)

Progesterone at this stage is secreted from placenta.

52. 53.

(2) (2)

26.

(4)

The matching disorder for Insulin is Diabetes mellitus.

54.

(2)

27.

(2)

Aldosterone increases the amount of sodium in blood.

Growth hormone is, therefore, called as tropic hormone.

55.

(3)

CCK causes the contraction of gallbladder

28.

(1)

56.

(4)

It enhances the life span of corpus luteum.

29. 30.

(4) (1)

57.

(1)

Buffalo’s hump is the symptom of Cushing’s syndrome.

58.

(2)

31. 32.

(3) (2)

Growth hormone in insects is also known as Ecdysone.

59.

(3)

60.

61.

(4)

Testosterone regulates the development of accessory reproductive organs and secondary sexual characters of males.

33. 34.

(3) (2)

62.

(1)

This syndrome is due excess secretion of glucocorticoids.

35.

(4)

63.

(3)

The receptors of rest three hormones are not present in plasma membrane.

36. 37. 38.

(4) (3) (2)

64.

(2)

65.

(3)

These corpuscles are present in the medulla part of thymus.

66.

(4)

39.

(4)

In this technique small paper pieces having female pheromones are thrown over an area due to which males are not able to locate females.

67.

(1)

Aldosterone helps in absorption of sodium from glomeruler filtrate. ADH is also associated with the osmo- regulation, but is not a corticoid hormone.

68.

(4)

ANP stimulates the loss of sodium in the urine and promotes diuresis.

69.

(1)

In this disease the destroyed bony tissue is replaced by cavities which are later filled with fibrous tissue.

70.

(3)

71.

(2)

de m

y.

bl

og

sp

ot

.c

om

(2)

The secretion of milk in mammals also, is regulated by Prolactin.

ca

72.

(2)

ic al a

ed m ee t

(3)

//n

47.

Vitamin-D3 is cholecalciferol. Both help in protein synthesis, and are anabolic in nature. Female intersexes have ovary as gonad and the secretion of male hormones can be from adrenal only. Cortisol is used in treating arthritis also. Simple goitre is due to the deficiency of Iodine. Both structures are non-secretory. Calcitonin is secreted from C-cells. STH is the major growth hormone. In Addison’s disease there is hyper- secretion of ACTH. This hormone also regulates the male pattern of development before birth. 48. (2) 49. (4) 50. (4)

s:

(2) (4) (3) (1) (2) (1) (2)

HCG is secreted from placenta. Nerve action is specific for a particular gland or muscle. Pineal body is attached to epithalamus. Prolactin stimulates mammary gland, which is not an endocrine gland. STH stimulates liver for the secretion of Somatomedin (hormone). Vasopressin is not secreted from anterior pituitary. Epinephrine inhibits saliva secretion. Both pituitary and adrenal medulla are ectodermal in origin. Volume of urine is governed by ADH, which is released from posterior lobe of pituitary.

ht tp

40. 41. 42. 43. 44. 45. 46.

(4)

Parathyroid hormone regulates calcium level in the blood. Thyroxin is derived from amino acid, Tyrosine. Alcohol increases the amount of urine by decreasing the secretion of ADH.

Hypoglycemia may develop due to excess or overdose of insulin hormone.