Biology today september 2016

21 Vol XVIII No 66 72 September 2016 Corporate Office: Plot 99, Sector 44 Institutional Area, Gurgaon -122 003 (HR), Tel : 0124-6601200 e-mail : info@mtg.in website : www.mtg.in Regd Office: 406, Taj Apartment, Near Safdarjung Hospital, Ring Road, New Delhi - 110029 Managing Editor : Mahabir Singh Editor : Anil Ahlawat 31 61 82 CONTENTS 42 48 46 NEET Essential Class XI Central and Peripheral Nervous System 21 NEET Foundation 31 High Yield Facts-Zoology Animal Kingdom 42 MPP-3 Subscribe online at Class XII 48 High Yield Facts-Botany Strategies for Enhancement in Food Production 61 MPP-3 Mathematics Today Chemistry Today Physics For You Biology Today 66 CBSE Board 2016 Solved Paper 2016 - Phase II 79 Concept Booster 82 Bio-Gram 83 You Ask, We Answer 84 Bioreporter 85 Crossword yr yrs yrs 330 330 330 330 600 600 600 600 775 775 775 775 Combined Subscription Rates Unitwise Practice Paper (Unit-I) 72 NEET www.mtg.in Individual Subscription Rates 46 Concept Map Competition Edge 83 79 yr PCM PCB PCMB 900 900 1000 yrs yrs 1500 1500 1800 1900 1900 2300 Send D.D/M.O in favour of MTG Learning Media (P) Ltd Payments should be made directly to : MTG Learning Media (P) Ltd, Plot 99, Sector 44 Institutional Area, Gurgaon - 122 003, Haryana We have not appointed any subscription agent Owned, Printed and Published by Mahabir Singh from 406, Taj Apartment, New Delhi - 29 and printed by Personal Graphics and Advertisers (P) Ltd., Okhla Industrial Area, Phase-II, New Delhi Readers are advised to make appropriate thorough enquiries before acting upon any advertisements published in this magazine Focus/Infocus features are marketing incentives MTG does not vouch or subscribe to the claims and representations made by advertisers All disputes are subject to Delhi jurisdiction only Editor : Anil Ahlawat Copyright© MTG Learning Media (P) Ltd All rights reserved Reproduction in any form is prohibited MT BIOLOGY TODAY | SEPTEMBER ‘16 The syllabus for NEET is very vast which impedes students from acquiring indepth knowledge and covering the entire syllabus at the same time An essential topic for NEET is therefore presented here to enable students grasp the topic, analyse the type of questions and SCORE HIGH CENTRAL AND PERIPHERAL NERVOUS SYSTEM CENTRAL NERVOUS SYSTEM MT BIOLOGY TODAY | SEPTEMBER ‘16 Cranium Cerebrospinal fluid (CSF) Brain The central nervous system (CNS) is the processing centre of the nervous system It receives and sends information to peripheral nervous system The brain and spinal cord are continuous structures, which together form the CNS They are both protected by hard bony coveringsthe brain by the cranium and the spinal cord by the vertebral column and by a continuous, tough, layered membrane called the meninges Both the brain and spinal cord are bathed in cerebrospinal fluid (CSF), which is continuously circulated through the cerebral ventricles, the cavity of the spinal cord and the sub-arachnoid space It serves as a pad to cushion the CNS from shocks and mechanical injuries The CSF also carries oxygen and nutrients from the blood to the neurons and neuroglia of the CNS Together, the brain and spinal cord act as the central control system of the body, receiving and interpreting sensory information from the rest of the body and sending back signals to glands and muscles for appropriate responses Ventricles Meninges Spinal cord Spinal cord cavity Vertebral column HUMAN BRAIN The human brain is the command centre for the human nervous system It receives input from the sensory organs and sends output to the effectors It processes and interprets sensory information sent from the spinal cord The brain is covered by three protective layers of connective tissue called meninges Dura mater Outermost, tough, fibrous membrane adhering closely to the inside of the skull Veins Arachnoid mater Thin “spider webby” structure Subdural space Space between arachnoid membrane and duramater Arachnoid granulation villi Sub-arachnoid space Space between arachnoid membrane and pia mater and is filled with CSF Longitudinal fissure Separates two cerebral hemispheres Pia mater Innermost, thin, very delicate and vascular membrane Cerebral cortex Cerebral vein Fig.: Diagram Showing Meninges of Brain Parts of Brain Human Brain i id d into i parts Divided Forebrain or Prosencephalon Includes olfactory lobes, cerebrum and diencephalon Midbrain or Mesencephalon Comprises of corpora quadrigemina and crura cerebri Hindbrain or Rhombencephalon Consists of cerebellum, pons varolii and medulla oblongata Parietal lobe of cerebral hemisphere Third ventricle Corpus callosum Anterior choroid plexus Frontal lobe of cerebral hemisphere Occipital lobe of cerebral hemisphere Anterior commissure Thalamus (encloses third ventricle) Pineal body (part of epithalamus) Corpora quadrigemina Hypothalamus Optic chiasma Infundibulum Pituitary gland Temporal lobe of cerebral hemisphere Mammillary body Pons Cerebral aqueduct Mid brain Cerebral peduncle of midbrain Arbor vitae Fourth ventricle Posterior choroid plexus Cerebellum Medulla oblongata Spinal cord Fig.: Median Section of Human Brain Forebrain Olfactory Lobes- Paired club shaped structure, forming anterior part of brain, concerned with sense of smell Each lobe consists of two parts - anterior olfactory bulb and posterior olfactory tract Cerebrum Largest and most complex part of human brain, consists of left and right hemispheres, connected by corpus callosum (large band of myelinated fibres) Cerebral cortex forms outermost portion of cerebrum and makes up the grey matter The surface of cortex is highly folded, forming gyri (upward folds) alternating with sulci (downward grooves) MT BIOLOGY TODAY | SEPTEMBER ‘16 Cerebral cortex forms white matter of the brain It contains million of medullated nerve fibres, connecting neurons of cerebral cortex with those located elsewhere in the brain Large concentration of medullated nerve fibres gives an opaque white appearance Motor Area s Lies in the frontal lobe s Transmit impulses to effectors s Control of voluntary muscles Parietal Lobe s Sensations s Language s Perception s Body awareness s Attention Sensory Area s Lies in the parietal lobe s Receive impulses from receptors s Perceive skin sensations (temperature, pressure, pain) Occipital Lobe s Vision s Perception Wernicke’s Area s Lies in the left temporal lobe s Language comprehension Frontal Lobe s Movement s Problem solving s Concentrating, thinking s Behaviour, personality, mood Cerebellum s Posture s Balance s Coordination of movement Broca’s Area s Lies in the frontal lobe s Speech control Temporal Lobe s Hearing s Language s Memory s Emotions Brain Stem s Consciousness s Breathing s Heart rate Fig.: Functional Areas of the Brain Diencephalon Epithalamus Thalamus Hypothalamus s Forms anterior choroid plexus s Lies superior to mid-brain s Hypothalamus lies above the pituitary gland and is attached to it by stalk called infundibulum s Short pineal stalk, have pineal body, s Composed primarily of grey secretes hormone melatonin matter s Maintains homeostasis, provides anatomical connections between nervous and endocrine systems Mid Brain s pairs of rounded protrusions present on upper or superior surface of mid brain are called corpora quadrigemina s One pair is called superior colliculi (concerned with sense of sight) and other pair is inferior colliculi (concerned with hearing) s The superior and inferior colliculi of each side are termed corpora bigemina Cerebral peduncles (crura cerebri) Mid Brain Corpora quadrigemina s Crura cerebri are two bundles of fibres present on lower or inferior surface of the mid brain s They relay impulses back and forth between the cerebrum, cerebellum, pons and medulla Hind Brain Cerebellum Second largest part of the human brain, consists of layers, outer layer of cells, cerebellar cortex and deeper cell clusters Middle layer contains characteristically large flask shaped Purkinje cells Cerebellum has two lateral cerebellar hemispheres and central worm shaped part, vermis It contains branching tree like arrangement of grey and white matter called arbor vitae (tree of life) Functions: Controls posture, balance and mainly involuntary activities, receives information from muscles, joints, skin, eyes 10 MT BIOLOGY TODAY | SEPTEMBER ‘16 Pons Varolii It is situated in front of cerebellum below the mid brain and above the medulla oblongata Functions: It relays impulses between the medulla oblongata and superior part of brain, between hemispheres of cerebellum and between cerebrum and cerebellum Pneumotaxic centre present in pons varolii limits inspiration Medulla Oblongata Pyramid shaped, extends from pons varolii above and is continuous with spinal cord below It has thin, non-vascular folded structure on its lower side called posterior choroid plexus Functions: Regulatory centres for heart rate, blood pressure, breathing, sneezing, salivation, coughing etc The mid brain, pons varolii and medulla oblongata are collectively called brain stem, connecting forebrain with spinal cord Limbic system – Consists of certain components of cerebrum and diencephalon – Main components are - (i) Hippocampus (ii) Amygdala (iii) Septal nuclei (iv) Mamillary bodies (v) Basal ganglia – It controls emotional behaviour, food habits and sex behaviour necessary for survival of species Also called “emotional brain” Ventricles of the Brain: Within the central nervous system is a system of hollow cavities called ventricles The network of linked cavities in the brain (cerebral ventricles) is continuous with the central canal of the spinal cord The ventricles are filled with cerebrospinal fluid which is produced by specialised epithelium located within the ventricles called the choroid plexus Lateral ventricles Present inside each hemisphere of the cerebrum Corpus callosum Interventricular foramen (Foramen of Monro) Connects lateral ventricle to the third ventricle Third ventricle Consists of narrow channel between the hemispheres through the area of thalamus Septum pellucidum Inferior tip of lateral ventricle Cerebral aqueduct or Aqueduct of Sylvius or iter Present in the midbrain portion of brainstem, connects third ventricle to fourth ventricle in pons and medulla Cerebellum Fourth ventricle Continuous with the central canal of the spinal cord, openings in fourth ventricle, allows CSF to move upward to the sub-arachnoid space that surrounds the brain and spinal cord Central canal Fig.: Ventricles of Human Brain CEREBROSPINAL FLUID (CSF) Functions The cerebrospinal fluid is secreted by anterior choroid plexus and posterior choroid plexus and is found inside the ventricles of the brain, the central canal of the spinal cord and in the sub-arachnoid space around the brain and spinal cord 12 Protection of brain and spinal cord by providing shock absorbing medium MT BIOLOGY Provides buoyancy to the brain, as brain is immersed in the CSF TODAY | SEPTEMBER ‘16 Excretion- CSF carries harmful metabolic wastes, drugs, and other substances from brain to the blood Endocrine medium for the brain - CSF carries hormones to different parts of the brain HUMAN SPINAL CORD Location-The spinal cord is a cylindrical shaped bundle of nerve fibres that is connected to the brain It runs down mid-dorsally, in the centre of the protective spinal column extending from the neck to the lower back It lies in the neural canal of veretebral column Spinal cord nerves transmit information from body organs and external stimuli to the brain and send information from the brain to other areas of the body Covering Meninges - The spinal cord is surrounded by three protective membranes; innermost piamater, middle arachnoid membrane and outer, tough duramater The sub-arachnoid space is filled with cerebrospinal fluid and the additional epidural space, above duramater contains fatty and connective tissues and veins Skull bone C1 nerve C1 vertebra Skull bone Foramen magnum C1 vertebra C1 Dorsal side Ventral side Dura mater Arachnoid mater Pia mater C7 vertebra T1 vertebra C8 T1 C7 vertebra T1 vertebra T1 nerve Fig : Coverings of Human Spinal Cord Posterior (dorsal) root ganglion Consists of cell bodies of dorsal nerve root, having sensory axons Posterior (dorsal) root spinal nerve Posterior grey horn Axons of dorsal nerve root forms synapse with other neurons, called interneurons Spinal nerve A spinal nerve arises from each side of cord, in each segment of spinal cord Anterior (ventral) root of spinal nerve Aggregations of motor axons from cell bodies present in anterior (grey) horn, form ventral nerve root Posterior median sulcus* White column White matter having bundles of myelinated nerve fibres Axon of sensory neuron Lateral grey horn Lies between anterior and posterior horn Grey matter Inner butterfly (H) shaped area of spinal cord, lacks myelin Cell body of sensory neuron Central canal Hollow, contains CSF Axon of motor neuron Anterior grey horn Contains cell bodies of motor neurons Nerve impulses for sensations Nerve impulses to effector tissues (muscles and glands) Anterior median fissure* Cell body of motor neuron Fig : T.S of Human Spinal Cord *Posterior median sulcus and anterior median fissure separate spinal cord into left and right symmetrical halves Functions- Spinal cord performs two main functions: (i) The stimuli are passed from and to the brain through the spinal cord (ii) It is the centre of spinal reflex action PERIPHERAL NERVOUS SYSTEM Peripheral nervous system (PNS) is the nervous system outside the brain and spinal cord It consists of cranial nerves (nerves originating from brain) and spinal nerves (nerves originating from spinal cord) MT BIOLOGY TODAY | SEPTEMBER ‘16 13 Cranial Nerves There are 12 pairs of cranial nerves They are so named because they pass through various openings in the cranial bones Table: Cranial nerves Name Origin Distribution Nature Functions Olfactory Olfactory epithelium in Olfactory lobe or bulb nasal cavity Sensory Smell Optic Retina of eye Optic lobe of midbrain Sensory Sight (Retina of eye) Oculomotor Floor of midbrain Eye, muscles of eyeball Motor Movements of eye-ball, iris, lens, eyelid and constriction of pupil Trochlear (Smallest cranial nerve) Floor of midbrain Superior oblique muscles of eyeball Motor Rotation of eyeball Trigeminal (Largest cranial nerve) Divided into three: (i) Opthalamic Ventral surface of pons varolii Mixed – (ii) Maxillary – (iii) Mandibular – Abducens Skin sensations Sensations Sensations, tongue movements, mastication External rectus muscle of eyeball Motor Rotation of eyeball Facial (bears Lower part of pons geniculate ganglion) varolii Anterior 2/3 tongue (taste buds), muscles of face, neck and salivary glands Mixed Taste, facial expression, chewing, movement of neck Auditory (also called Comes from internal vestibulo-cochlear) ear and joins lateral side of pons varolii Organ of Corti in cochlea, semicircular Sensory canals Hearing and equilibrium Glosso-pharyngeal Lateral side of medulla Posterior 1/3rd of tongue, soft palate and muscles of pharynx Mixed Taste and touch, movements (swallowing) of pharynx, salivation 10 Vagus (Pneumogastric) (Longest cranial nerve) (i) Superior laryngeal (ii) Recurrent laryngeal (iii) Cardiac (iv) Pneumogastric (v) Depressor Lateral side and floor of medulla Muscles of pharynx, vocal cords, lungs, heart, oesophagus, stomach Also called wandering nerve as it has maximum branches Mixed Vocal cords (sound production), lungs, respiratory reflexes, peristaltic intestine movements, speech, swallowing, secretion of gastric glands, inhibition of heart beat 11 Spinal accessory nerves Both medulla and spinal cord Muscles of palate, larynx, vocal cords, neck, shoulder Motor Movement of muscles of pharynx, larynx, neck, shoulder 12 Hypoglossal Ventral side of medulla Muscles of tongue, hyoid apparatus oblongata Motor Movement of tongue 14 MT BIOLOGY Pons varolii Lacrimal glands, conjunctiva of eye, Sensory skin of forehead, eyelids etc Cheeks, upper gums, upper teeth Sensory and lower eyelids Teeth and gums of lower jaw, pinna Mixed of the ear, lower lip and tongue TODAY | SEPTEMBER ‘16 Olfactory (I) sensory: nose Intermediate motor: submaxillary and sublingual gland Optic (II) sensory: eye I II Trochlear (IV) motor: superior oblique muscle sensory: anterior part of tongue and I intermediate soft palate Vestibulocochlear nerve (VIII) sensory: inner ear II III Abducens (VI) Oculomotor (III) motor: external motor: all eye rectus muscle muscles except those supplied by IV and VI VII VIII IX X XI V IV III VI VI IV XII Sensory: posterior part of tongue, tonsil, pharynx vestibular cochlear V Vagus (X) motor: heart, lungs, bronchi, gastrointestinal tract VII VIII IX X XI Sensory: heart, lungs, bronchi, trachea, larynx, pharynx, gastrointestinal tract, external ear XII Trigeminal (V) sensory: face, sinuses, teeth, etc motor: muscles of mastication Accessory (XI) motor: muscles of pharynx, larynx, neck Hypoglossal (XII) motor: muscles of the tongue Facial (VII) motor: muscles of the face Glossopharyngeal (IX) motor: pharyngeal musculature Fig.: Cranial Nerves SPINAL NERVES There are 31 pairs of spinal nerves, named and numbered according to the vertebrae with which they are associated 31 pairs of spinal nerves Cervical nerves (8 pairs) Thoracic nerves (12 pairs) Lumbar nerves (5 pairs) Coccygeal nerves Sacral nerves (5 pairs) (1 pair) Structure - The spinal nerves are formed by union of dorsal and ventral roots shortly after they leave spinal cord Each spinal nerve has afferent (sensory) and efferent (motor) fibres, in general, efferent comes from ventral root and afferent go into dorsal root Thus, all spinal nerves are mixed nerves because they carry both sensory and motor impulses – After leaving vertebral column, each spinal nerve divides into: Posterior branch- innervates muscles and skin of the posterior portion of the body Anterior branch- innervates limbs and the lateral and anterior portions of the body The main spinal nerves join to form plexus Cervical plexus Innervates neck and diaphragm Coccygeal plexus Innervates skin and pelvic region Lumbar plexus Innervates the legs Brachial plexus Innervates chest and arm Sacral plexus Connects pelvic region Autonomic Nervous System (ANS) This system controls and coordinates involuntary activities of various organs, e.g., secretion of digestive fluid ANS is divisible into two parts: Sympathetic and parasympathetic neural system MT BIOLOGY TODAY | SEPTEMBER ‘16 15 Contd from page no 30 SOLUTIONS OF NEET FOUNDATION CHAPTER-11 : TRANSPORT IN PLANTS 11 12 (a) (c) (c) (b) (c) (b) A-(ii), B-(iv), C-(i), D-(iii) A-(vi, viii), B-(iii, v), C-(ii, vii), D-(i, iv) (d) (d) (c) 10 (b) 13 (i) Translocation (ii) source (iii) sink (iv) multidirectional (v) lateral translocation (vi) mass flow hypothesis (vii) turgor pressure (viii) sieve tubes (ix) flow (x) low turgor pressure 14 (a) 15 (c) 16 (d) 17 (a) 18 (b) 19 (a) The given experimental set up is demonstrating ascent of sap in plants (b) Eosine imparts a red colour to all the veins in the leaf Eosine in dilute solution is used for staining living tissues It is useful in studying venation and tracing the vascular bundles, as it rises upwards along with water, to the stem and leaves Thus, stains tissues involved in its transport (c) The eosin solution is translocated from the beaker to the veins through vascular bundles Since the vein possess the xylem of vascular bundles, the red colour (eosin) reaches from solution to the leaves All the vessels of stem and leaves involved in ascent of sap will show red colour 20 (a) A - stomatal pore, B- guard cell, C-microfibrils (b) The two functions of stomata are: (i) Gaseous exchange (iii) Transpiration (c) ‘C’ are cellulosic microfibrils that are oriented specifically to help in opening and closing of stomata (b) (c) CHAPTER-13 : PHOTOSYNTHESIS IN HIGHER PLANTS 11 12 13 14 19 (b) (c) CHAPTER-12 : MINERAL NUTRITION 11 12 13 14 19 (b) (c) 20 64 (b) (c) (d) (c) (a) (b) (b) (d) (a) 10 (c) A-(iv), B-(ii), C-(i), D-(v), E-(iii) A-(iii, ix, x) B-(v, vii) C-(ii, iv) D-(i, vi), E-(viii) (i) nitrate (ii) nitrate reductase (iii) nitrite reductase (iv) ferrodoxin (v) ammonia (vi) aspartate (vii) glutamine synthetase (viii) glutamine (ix) transamination (x) Glutamic acid (a) 15 (d) 16 (a) 17 (b) 18 (c) (a) Aeroponics The nutrient solution is whipped into a nutrient mist by rotor which is driven by motor The roots suspended in air, over the nutrient solution absorbs them (the nutrients) from clouds formed in the air Some successfully grown crops via aeroponics are tomato, cucumber, basil, thyme, strawberry etc (a) A- Curling of root hair around the bacteria B- Formation of infection thread C- Infection of cortical cells by bacteria MT BIOLOGY TODAY | SEPTEMBER ‘16 D- Formation of bacteriods in infected cells, which enlarge to form nodules The bacteria Rhizobium occurs symbiotically with any leguminous plant such as Glycine max (soya bean) Nitrogen fixation is carried out by symbiotic bacteria, inside the nodules The process is catalysed by enzyme nitrogenase It requires elements iron and molybdenum (cofactors) for its functioning 20 (b) (c) (b) (b) (c) (c) (d) (c) (c) (d) (b) 10 (c) A-(iii), B-(v), C-(iv), D-(ii), E-(i) A-(iii, x), B-(iv, v, viii), C-(ii, vii), D-(vi), E-(i, ix) (i) RuBP (ii) CO2 (iii) O2 (iv) photorespiration (v) Hatch-Slack pathway (vi) Kranz anatomy (vii) PEPcase (viii) bundle sheath (ix) CAM (x) stomata (d) 15 (b) 16 (c) 17 (b) 18 (a) (a) X, Y and Z represent the points at which light ceases to be the major limiting factor in all the above cases shown Transitional curves are produced when either of the two factors change the rate of the process This occurs because the cells possess large and numerous chloroplasts in them, of which some receive more light while others get excess of CO2 Thus, rate of the process is affected Light intensity acts as a limiting factor in a shaded community such as wood, dawn and twilight in a warm climate, while temperature acts as a limiting factor on a bright winter day (a) A-1,3, diphosphoglyceric acid B- Fructose phosphate C- Ribulose biphosphate The above cycle is Calvin cycle The important steps in Calvin cycle are -(i) Carboxylation, (ii) Glycolytic reversal and (iii) Regeneration of RuBP Calvin cycle occurs in bundle sheath cells of C4 plants CHAPTER-14 : RESPIRATION IN PLANTS 11 12 13 (a) (b) (b) (c) (c) (b) (d) (c) (b) 10 (b) A-(v), B-(iii), C-(iv), D-(i), E-(ii) A-(iii, v, ix), B-(i), C-(iv, viii), D-(ii), E-(vi, vii, x) (i) FADH2 (ii) ATP (iii) CO2 (iv) NADH (v) two (vi) matrix (vii) FADH2 (viii) NADH (ix) FADH2 (x) pump 14 (d) 15 (c) 16 (a) 17 (a) 18 (d) 19 (a) The above experimental set up demonstrates anaerobic respiration in seeds (b) (c) As in the given experimental set up the test tube is filled with mercury initially, so, it indicates that there is complete absence of air or oxygen But after sometime, as shown in experiment, the level of mercury falls down in the test tube This is due to accumulation of some gas in the test tube The gas is released due to anaerobic respiration in seeds, since oxygen is unavailable Anaerobic respiration does not always release CO2 as end product E.g., lactic acid fermentation, where lactic acid and NAD are produced by fermentation of pyruvic acid 20 (a) A- FMN, B-Ubiquinone, C-Cytochrome c, D-Cytochrome a3 (b) The complexes involved in electron transfer in ETC are: Complex I - NADH dehydrogenase complex (FMN and Fe-S complexes) Complex II - Succinate Q-reductase complex (ubiquinone) Complex III - Cytochrome c reductase complex (cytochrome b, FeS complex and cytochrome c1) Complex IV - Cytochrome c oxidase complex (cytochrome a and a3) (c) The enzyme required for ATP synthesis is ATP synthase It is present in the inner mitochondrial membrane and comprises of a head (F1), stalk and base (F0) The ATP synthase becomes active only when there is a proton gradient having higher concentration of H+ on F0 side as compared to F1 side CHAPTER-15 : PLANT GROWTH AND DEVELOPMENT 11 12 13 (b) (c) (d) (d) (c) (a) (b) (a) (c) 10 (b) A-(iii), B-(v), C-(ii), D-(iv), E-(i) A-(iv, ix), B-(v, viii), C-(iii, x), D-(i, vi), E-(ii, vii) (i) phytohormones (ii) synergetically (iii) (v) (vii) (ix) 14 (a) antagonistically cytokinin shooting gibberellins 15 (d) 16 (b) (iv) auxin (vi) rooting (viii) ethylene (x) abscisic acid 17 (c) 18 (b) 19 (a) Leaves A and B signify heterophylly i.e., occurrence of different types of leaves under different environmental conditions The leaf ‘A’ belongs to submerged species buttercup and therefore, is highly dissected whereas leaf ‘B’ belongs to emergent buttercup species and thus, is broad and lobed (b) The phenomenon exhibited by these leaves is environmental plasticity It refers to the ability to change structure under the influence of external or environmental stimuli (c) Plants like Larkspur and Hedera helix (ivy) show intrinsic plasticity In Larkspur, the juvenile leaves are highly dissected while mature leaves are pinnately divided with lobes becoming linear in the region of flowers Similarly in Hedera (ivy), juvenile plant is a root climber having alternate palmately lobed leaves while adult plant has bushy habit with opposite entire leaves 20 (a) A - Short day plant B - Long day plant C - Day neutral plant (b) Short day plants - Sugarcane, strawberry Long day plants - Wheat, radish, oat Day neutral plants - Tomato, maize (c) Short-long day plants need short photoperiods for floral initiation and long photoperiods for blossoming, while long-short day plants require long photoperiods for floral initiation and short photoperiods for blossoming  MT BIOLOGY TODAY | SEPTEMBER ‘16 65 GENERAL INSTRUCTIONS (i) All questions are compulsory (ii) This question paper consists of five Sections A, B, C, D and E Section A contains questions of one mark each Section B contains questions of two marks each, Section C contains 12 questions of three marks each Section D contains question of VBQ type with four marks and Section E contains questions of five marks each (iii) There is no overall choice However, an internal choice has been provided in one question of marks, one question of marks and all the three questions of marks weightage A student has to attempt only one of the alternatives in such questions (iv) Wherever necessary, the diagrams drawn should be neat and properly labelled OR SECTION - A A scientist studied two semen samples A and B and found that sample A lacked fructose while sample B lacked citric acid What could be the reason? State two methods of apomictic development in seeds Write the names of hormones which stimulate milk production and milk ejection respectively Name the type of ovule in which body of the ovule gets inverted, and micropyle and funiculus lie side by side Give an example where an organism despite being hermaphrodite copulates in order to reproduce SECTION - B The chances of survival of offspring of viviparous animals are more than the offspring of oviparous animals Justify the statement with reasons SECTION - C 11 (i) Draw a well labelled diagram of a human sperm (ii) Which part of the sperm provides energy for its movement? 12 ‘Viviparity limits the number of offspring in a litter’ Explain 13 Write a short note on fertilizin-antifertilizin reaction What is the significance of fertilisation? 14 (i) Where is acrosome present in human sperm? Differentiate between monocarpic and polycarpic plants (ii) Name the organelle that contributes in its formation What is parturition? Where does the signals for parturition start from? (iii) State its function Name the IUDs which release mineral ions Why they are considered good contraceptives? A bilobed dithecous anther contains 50 pollen mother cells (PMCs) per microsporangium How many male gametophytes can be produced by this anther? 10 Study the given figure and answer the following questions (i) Name the type of reproduction shown in the figure (ii) Write two advantages of this type of reproduction (iii) Give name of another animal which shows same type of reproduction 66 MT BIOLOGY TODAY SEPTEMBER ‘16 15 How does the megaspore mother cell develop into an embryo sac? Elaborate 16 Males in whom testes fail to descend to the scrotum are generally infertile Why? 17 What deter the persons infected of STDs from going for timely detection and proper treatment? What complications it can lead to, in future? 18 Why menstruation does not occur during pregnancy? 19 (i) (ii) (iii) Mention the function of each of the following: Tassels of corn cob Sertoli cells of seminiferous tubules Tapetum in microsporangium OR Give an example of one organism each which reproduces by the following modes of asexual reproduction: (i) Fragmentation (ii) Budding (iii) Conidia formation 20 “Gametogenesis and meiosis are always linked” Justify the statement 21 Give an account of foetal ejection reflex OR (i) Name the hormonal composition of the oral contraceptive pills used by human females Explain how does it act as a contraceptive (ii) Amniocentesis for sex determination is banned in our country Is this ban necessary? Comment (iii) During evolution, sexual reproduction seems to gradually dominate asexual reproduction Similarly internal fertilisation replaced external fertilisation in higher organisms Elaborate the possible reasons 22 Discuss the mode of action of hormonal contraceptives SECTION - D 23 Abhay and his wife Anu are married for the last years, but they not have their own child They have undergone various tests in infertility clinics and the reports showed Abhay to be infertile However, Anu’s in-laws are not accepting this truth and are blaming Anu for being childless (i) Do you think Anu’s in-laws are correct for not accepting the truth and blaming her for the infertility? Give reasons in support of your answer (ii) What are the ways by which this couple could be assisted to have their own child? SECTION - E 24 Define polyembryony and its types OR (i) At what stage the ovum is released from the ovary? When and where does the maturation of this stage occurs? (ii) Give a schematic representation of menstrual cycle (iii) Write a note on test tube baby programme 25 Describe the post-zygotic events leading to implantation and placenta formation in humans Mention any two functions of placenta OR Diagrammatically explain the process of gametogenesis in both males and females 26 Give reasons why: (i) Most zygotes in angiosperms divide only after certain amount of endosperm is formed (ii) Micropyle remains as a small pore in the seed coat of a seed (iii) Integuments of an ovule harden and water content is highly reduced as the seed matures (iv) Anthers of angiospermic flowers are described as dithecous (v) Organisms produced due to sexual reproduction adapt better to the changing environmental conditions SOLUTIONS Men from which samples A and B were collected may have some dysfunctioning of seminal vesicles and prostate gland respectively The two common methods of apomictic development are recurrent agamospermy and adventive embryony Milk production is stimulated by hormone prolactin and ejection of milk is stimulated by oxytocin Anatropous (or inverted) ovule is the type of ovule in which body of the ovule gets inverted and micropyle and funiculus lie side by side Earthworm is one such organism where copulation and cross fertilisation are required for reproduction, inspite of it being hermaphrodite (both male and female sex organs present in single individual) It is because, in earthworm testes mature earlier than the ovaries (protandry) Differences between monocarpic plants and polycarpic plants: Monocarpic Plants Polycarpic Plants (i) Monocarpic plants flower Polycarpic plants flower every only once in their life year in particular season (ii) These plants are generally These plants are perennial annual or biennial (iii) Monocarpic plats die after Polycarpic plants not die flowering and fruiting after flowering and fruiting (iv) Examples: Rice, Wheat, Examples: Apple, Mango, Grape Radish, Carrot, Bamboo, etc wine, Orange, etc The act of expelling the full term young one from the mother’s uterus at the end of gestation period is called parturition The signals for parturition start from the fully matured foetus and placenta which induce mild uterine contractions called foetal ejection reflex This leads to quick release of oxytocin from the maternal posterior lobe of pituitary gland CuT and Multiload 375 are copper releasing IUDs The Cu2+ ions released by these IUDs suppress sperm motility and the fertilising capacity of the sperms, and thus, helps in preventing conception MT BIOLOGY TODAY SEPTEMBER ‘16 67 A bilobed dithecous anther consists of four microsporangia In the given case, each microsporangium contains 50 pollen mother cells (PMCs), therefore total 200 PMCs will be present in this anther As each PMC produces pollen grains which develop into male gametophytes, therefore, pollen grains or male gametophytes produced by this anther will be 800 (=200 × 4) 10 (i) The figure shows asexual reproduction by budding in Sycon (a sponge) (ii) Two advantages of budding are: (a) rapid multiplication (b) production of genetically identical individuals (iii) Hydra also shows asexual reproduction by budding OR On the basis of the development of zygote, animals are grouped into oviparous and viviparous The oviparous animals, such as reptiles and birds lay eggs Their fertilised eggs are covered by hard calcareous shell and are laid in a safe place in the environment The development of zygote takes place outside the female's body After incubation period, young ones hatch out In viviparous animals, such as majority of mammals including human beings, the zygote develops into a young one inside the female's body After a certain growth period, the young ones are delivered by the female individual Due to proper care and protection, the chances of survival of young ones are more in viviparous individuals while oviparous offsprings are at a greater risk than viviparous ones 11 (i) Labelled diagram of a human sperm is as following: (ii) The mitochondrial spiral present in middle piece of the sperm provides energy for its movement 12 Viviparity is a form of reproduction in animals in which the development of embryos takes place within the female's body The embryo obtains its nourishment directly from mother via placenta or by other means and subsequently mother gives birth to full term young one Viviparity limits the number of offspring in a litter due to the following reasons: (i) As the number of eggs released during ovulation are limited during oestrous or menstrual cycle, so the number of eggs fertilised during reproductive cycle of female are also limited (ii) As the entire period of development called gestation is passed within mother’s body, it restricts the number of embryo that can develop together at one time (iii) During gestation no ova or eggs are released 13 According to fertilisation theory, egg (ovum) secretes a chemical named fertilizin and sperm has on its surface a protein substance called antifertilizin The fertilizin of an egg interacts with the antifertilizin of a sperm of the same species This interaction makes the sperms stick to the egg surface The adhesion of sperm to the egg of the same species through chemical recognition is known as agglutination Fertilisation has the following significances: (i) It restores the diploid number of chromosomes, characteristic of the species viz., 46 in human beings (ii) Initiates cleavage (iii) It combines the characters of two parents This introduces variations (iv) Fertilisation membrane developed after the entry of the sperm prevents the entry of other sperms into the ovum 14 (i) An acrosome is present at the anterior end of the head of sperm (ii) It is formed from Golgi body of the spermatid (iii) Acrosome contains proteolytic and lysosomal enzymes known as sperm lysins, e.g., hyaluronidase, corona penetrating enzyme, acrosin or zona lysine These enzymes are used to contact and penetrate the egg at the time of fertilisation 15 The diploid megaspore mother cell (MMC) undergoes meiotic division and produces four haploid megaspores One of the megaspore is functional while other three degenerate The functional megaspore is the first cell of female gametophyte or embryo sac The nucleus of megaspore divides by mitosis into eight daughter nuclei Two polar nuclei are present in centre which may fuse to form a diploid or secondary nucleus Three nuclei at the base of embryo sac form antipodal cells 68 MT BIOLOGY TODAY SEPTEMBER ‘16 The remaining three nuclei at the micropylar end constitute egg apparatus Thus, a typical angiospermous embryo sac comprises of cells and nuclei 16 Spermatogenesis, the process of formation of sperms takes place in testes During early foetal life the testes develop in the abdominal cavity but during the 7th month of the gestation they descend into the scrotum (a pouch divided into two separate sacs) Scrotum provides about 2-2.5 °C lower temperature than internal body temperature Sperms need slightly lower temperature than body temperature to survive If testes fail to descend into scrotum, sperms will get killed at high temperature present in abdomen and thus, making males infertile 17 Absence or less significant symptoms in the early stages of infection and the social stigma attached to the STDs, deter the infected persons from going for timely detection and proper treatment This could lead to complications later, which include pelvic inflammatory diseases (PID), abortions, still births, ectopic pregnancies, infertility or even cancer of the reproductive tract 18 Menstrual phase is caused by decreased levels of progesterone and estrogen During pregnancy, luteinising hormone (LH) secreted by the anterior lobe of the pituitary gland maintains corpus luteum that secretes large amount of progesterone Progesterone is pregnancy maintaining hormone, as it maintains endometrium of uterus and causes it to grow Such an endometrium is necessary for implantation of the fertilised ovum and other events of pregnancy and for menstruation to occur, the levels of the progesterone and estrogen in the blood must be reduced Therefore, during pregnancy, the menstruation does not occur 19 (i) Tassels of corn cob represent the male inflorescence present at top of the plant male flowers which produce pollen grains to fertilise the female flowers (ii) Sertoli cells support developing germ cells and provide then with nourishment especially spermatids They also secrete Androgen Binding Protein (ABP) that concentrates testosterone in the seminiferous tubules and another protein, called inhibin which suppresses FSH synthesis (iii) Tapetum is the innermost layer of microsporangium and serves the following functions: – Nourishes developing PMCs and pollen grains – Produces Ubisch granules containing sporopollenin for exine formation – Produces special proteins to recognise compatibility during pollen-pistil interaction – Produces pollen kitt in entomophilous flowers – Secretes enzymes for the degradation of callose wall and separation of pollen tetrads OR (i) Fragmentation is found in sponges, coelenterates (sea anemone), echinoderms (starfish), algae (Spirogyra), fungi (Rhizopus) etc (ii) Exogenous budding occurs in yeasts, Hydra, Sycon etc Endogenous budding through gemmule formation occurs in Spongilla etc (iii) Conidia are the exogenous non-motile asexual spores produced in some members of Ascomycetes e.g., Penicillium 20 Sexual reproduction involves fusion of male and female gametes to form zygote (first cell of new individual) Gametogenesis is the process of formation of male and female gametes For the continuity of race and maintenance of chromosome number, the zygote formed by fusion of gametes should have the same diploid number as that of parents Meiosis is the reduction division where the chromosome number of the dividing cell is halved and a single diploid cell gives rise to four haploid cells or gametes Hence, gametogenesis is always linked to meiosis 21 The signals for parturition (child birth) which originate from the fully matured foetus and placenta and induce mild uterine contractions are called foetal ejection reflex This causes release of oxytocin (birth hormone) from the maternal posterior lobe of pituitary gland Amount of oxytocin increases just before and during labour pains It causes contraction of uterine muscles which ultimately lead to parturition 22 The mode of action of various hormonal contraceptives is discussed as follows: (i) Hormone releasing Intra uterine devices such as progestasert and LNG-20 increase phagocytosis of sperms within uterus They turn the cervix hostile to spermatozoa and make the uterus unsuitable for implantation (ii) Pills inhibit ovulation, motility and secretory activity of oviducts They alter uterine endometrium, making it unsuitable for implantation (iii) Subcutaneous implants–It involves insertion of six match stick sized capsules containing synthetic progesterone under the skin of inner arm, above the elbow It acts by blocking ovulation and preventing sperm transport by thickening the cervical mucus (iv) Hormone injections – These are progesterone injections which are given once every months and release hormone slowly and prevent ovulation MT BIOLOGY TODAY SEPTEMBER ‘16 69 23 (i) Anu's inlaws shows an irresponsible behaviour by blaming her for being childless because of a common myth in our society, that childlessness can be due to infertility of female and has nothing to with male’s fertility Anu’s inlaws have the same misconception and fear that accepting the truth would hamper Abhay’s manhood Infertility in males could be due to various reasons like physical or congential diseases, endocrinal or immunological dysfunction or even psychological problems Her in-laws should understand the fact that both ‘husband and wife’ share this responsibility and fertility is the function of husband-wife unit They should ask Abhay to get treated for infertility (ii) Infertile couples could be assisted to have children through special techniques commonly called as Assisted Reproductive Technologies (ART) In vitro fertilisation (IVF) followed by Embryo Transfer (ET) is one such techniquen in which fertilisation takes place outside the female's body, in almost similar conditions as that in the body Other techniques are Gamete Intra Fallopian Transfer (GIFT), Artificial Insemination (AI) and Intra Cytoplasmic Sperm Injection (ICSI) All these techniques require high precision handling by specialised professionals Proper counselling of couples should be done before such treatments 24 Polyembryony was discovered by Leeuwenhoek (1719) in Citrus Polyembryony is the phenomenon of developing more than one embryo in the same seed Polyembryony can be: (a) Simple polyembryony : Presence of more than one embryo sac and hence oosphere, e.g., Brassica (b) Mixed polyembryony : More than one pollen tube entering an ovule and fertilising synergid or an antipodal cell, e.g., Ulmus (c) Cleavage polyembryony : Cleavage or splitting of one embryo into two or more embryos, e.g., Orchids, Nymphaea, Nicotiana (d) Adventitive polyembryony : Diploid nucellar or integumental cells proliferate to form embryos, e.g., Citrus, Opuntia, Mangifera Polyembryony is called true if extra embryos develop from the same embryo sac in the ovule and false if extra embryos are formed in different embryo sacs in the ovule OR (i) Ovum is released from the ovary in the secondary oocyte stage The maturation of secondary oocyte is completed in the Fallopian tube after the entry of the sperm for fertilisation 70 MT BIOLOGY TODAY SEPTEMBER ‘16 (ii) Fig: Schematic representation of menstrual cycle (iii) In test tube baby programme, ova from the wife/donor (female) and sperms from the husband / donor (male) are collected and are induced to form zygote under simulated conditions in the laboratory Zygote is allowed to divide forming blastomeres The zygote or early embryos (with upto blastomeres) could then be transferred into the Fallopian tube (ZIFT-Zygote Intra Fallopian Transfer) and embryos with more than blastomeres are transferred into the uterus (IUT-Intra Uterine Transfer), to complete its further development Thus, in vitro fertilisation (IVF) - fertilisation outside the body in almost similar conditions as that in the body followed, by embryo transfer (ET) 25 After the formation of zygote, a rapid series of mitotic divisions (called cleavage) of the zygote occurs as it moves through the isthmus of the oviduct towards uterus The new daughter cells formed after division are called blastomeres The embryo with solid mass of 8-16 blastomeres is called a morula The morula continues to divide further and transforms into blastocyst and reaches the uterus The blastomeres in the blastocyst get arranged into an outer layer called trophoblast and an inner group of cells attached to trophoblast called the inner cell mass The trophoblast layer then gets attached to the endometrium and the inner cell mass gets differentiated as the embryo After attachment, the uterine cells divide rapidly and covers the blastocyst As a result, the blastocyst becomes embedded in the endometrium of the uterus This is called implantation and it leads to pregnancy The outer surface of the chorion (foetal membrane) develops a number of finger like projections, called chorionic villi, which grow into the tissue of the uterus These villi, penetrate the tissues of the uterine wall in which they are embedded, to make up the organ known as placenta The placenta facilitates the supply of oxygen and nutrients to the embryo and also removal of carbon dioxide and other waste materials produced by the embryo It also acts as an endocrine tissue and produces several hormones like human chorionic gonadotropin (hCG), human placental lactogen (hPL), oestrogen, progesterone, etc., for the maintenance of pregnancy OR Refer to answer 11 and 12, page 76 "MTG Excel in Biology" 26 (i) Most zygotes in angiosperms divide only after certain amount of endosperm is formed so as to obtain nutrition from the endosperm for the developing embryo (ii) Micropyle remains as a small pore in the seed coat of a seed so as to allow the entry of water and oxygen into the seed at the time of germination (iii) The integuments of the ovule lose their protoplasm, develop thick and impermeable walls, and get transformed into seed coats (i.e., testa and tegmen) This is to protect the seed when it is in the state of dormancy and until favourable conditions return for germination (iv) A dithecous anther is the one that contains two anther lobes Each anther lobe contains two microsporangia, thus, a dithecous anther is tetrasporangiate Most angiospermic flowers possess dithecous and tetrasporangiate anthers (v) The offsprings formed due to sexual reproduction contain the genetic material of both the parents, as they are formed by the fusion of gametes from different parents and gamete formation (through meiosis) involves recombinations, resulting in variations Variations are a major factor of natural selection and therefore, the organisms produced due to sexual reproduction adapt better to the changing environmental conditions In haplontic organisms (haploid main body), meiosis occurs after zygote is produced hence, variations arise at post fertilisation stage OR (i) Oral contraceptives used by human females contain progesterone alone or a combination of progesterone and oestrogen They act as contraceptives in four ways: (a) Inhibition of ovulation (b) Inhibition of motility and secretory activity of oviducts (Fallopian tubes) (c) Changes in cervical mucus impairing its ability to allow passage and transport of sperms (d) Alteration in uterine endometrium to make it unsuitable for implantation (ii) Amniocentesis is a prenatal diagnostic technique to determine the genetic disorders of the foetus Unfortunately, the useful technique of amniocentesis is being misused to kill the normal female foetuses as it also helps to detect the sex of the foetus (iii) Higher organisms though show complexity, yet reproduce sexually because it enables these organisms to survive during unfavourable conditions It contributes to evolution of the species by introducing variations in a population much more rapidly than asexual reproduction Thus, sexual reproduction dominates asexual reproduction and is predominantly present in higher organisms External fertilisation occurs outside the body of the organism whereas internal fertilisation occurs inside the body of the female A major disadvantage of external fertilisation is that the offsprings are not protected from the predators and their survival is threatened upto adulthood More over a large number of gametes are wasted Thus, internal fertilisation which occurs in higher plants and animals has replaced external fertilisation in due course of time  MPP-3, Class XII 11 16 21 26 31 36 (b) (a) (a) (a) (b) (c) (a) (c) 12 17 22 27 32 37 ANSWER KEY (a) (c) (d) (b) (c) (c) (a) (b) 13 18 23 28 33 38 MT BIOLOGY (c) (c) (b) (a) (a) (d) (a) (c) 14 19 24 29 34 39 (a) (b) (c) (d) (a) (a) (a) (a) TODAY SEPTEMBER ‘16 10 15 20 25 30 35 40 (b) (d) (c) (a) (a) (b) (d) (a) 71 e-II Phas n o held ly th Ju 24 Here, the references of few are given : S No MTG Books Q No P No S No 21 31 29 years NEET  AIPMT 7/ 49 25(XI)/ 35 29 years NEET  AIPMT/NEET Guide NCERT Fingertips 31 27 (XI) 39 NCERT Fingertips NCERT Fingertips 94 (XI) 45 NCERT Fingertips/NEET Guide 29 years NEET  AIPMT 40 81 47 NCERT Fingertips 29 years NEET  AIPMT NCERT Fingertips/ 29 years NEET  AIPMT Q No P No 360 28/8 450/567 49 311(XII) 46/86 396(XII)/642 63 7(XI) 10 NCERT Fingertips 72 106 (XI) 52 29 years NEET  AIPMT 187 16 29 years NEET  AIPMT 73 123 61 NEET Guide 55 325 17 NCERT Fingertips 29 years NEET  AIPMT 10/28,33 227(XI)/152,153 68 48/38 451(XI)/248 320 18 NCERT Fingertips/ 29 years NEET  AIPMT 40/3 325(XI)/187 20 NCERT Fingertips/ 29 years NEET  AIPMT 43/34 349(XI)/198 Methanogens belong to (a) Eubacteria (b) Archaebacteria (c) Dinoflagellates (d) Slime moulds Select the wrong statement (a) The walls of diatoms are easily destructible (b) ‘Diatomaceous earth’ is formed by the cell walls of diatoms (c) Diatoms are chief producers in the oceans (d) Diatoms are microscopic and float passively in water The label of a herbarium sheet does not carry information on (a) date of collection (b) name of collector (c) local names (d) height of the plant MT BIOLOGY NCERT Fingertips/29 years NEET AIPMT Which one of the following is wrong for fungi? (a) They are eukaryotic (b) All fungi possess a purely cellulosic cell wall (c) They are heterotrophic (d) They are both unicellular and multicellular 72 MTG Books TODAY SEPTEMBER ‘16 69 29 years NEET  AIPMT and more such questions …… Conifers are adapted to tolerate extreme environmental conditions because of (a) broad hardy leaves (b) superficial stomata (c) thick cuticle (d) presence of vessels Which one of the following statements is wrong? (a) Algae increase the level of dissolved oxygen in the immediate environment (b) Algin is obtained from red algae, and carrageenan from brown algae (c) Agar-agar is obtained from Gelidium and Gracilaria (d) Laminaria and Sargassum are used as food The term ‘polyadelphous’ is related to (a) gynoecium (b) androecium (c) corolla (d) calyx How many plants among Indigofera, Sesbania, Salvia, Allium, Aloe, mustard, groundnut, radish, gram and turnip have stamens with different lengths in their flowers? (a) Three (b) Four (c) Five (d) Six Radial symmetry is found in the flowers of (a) Brassica (b) Trifolium (d) Cassia (c) Pisum 10 Free-central placentation is found in (a) Dianthus (b) Argemone (c) Brassica (d) Citrus 11 Cortex is the region found between (a) epidermis and stele (b) pericycle and endodermis (c) endodermis and pith (d) endodermis and vascular bundle 12 The balloon-shaped structures called tyloses (a) originate in the lumen of vessels (b) characterise the sapwood (c) are extensions of xylem parenchyma cells into vessels (d) are linked to the ascent of sap through xylem vessels 13 A non-proteinaceous enzyme is (a) lysozyme (b) ribozyme (c) ligase (d) deoxyribonuclease 14 Select the mismatch (a) Gas vacuoles – Green bacteria (b) Large central vacuoles – Animal cells (c) Protists – Eukaryotes (d) Methanogens – Prokaryotes 15 Select the wrong statement (a) Bacterial cell wall is made up of peptidoglycan (b) Pili and fimbriae are mainly involved in motility of bacterial cells (c) Cyanobacteria lack flagellated cells (d) Mycoplasma is a wall-less microorganism 16 A cell organelle containing hydrolytic enzymes is (a) lysosome (b) microsome (c) ribosome (d) mesosome 17 During cell growth, DNA synthesis takes place in (a) S-phase (b) G1-phase (c) G2-phase (d) M phase 18 Which of the following biomolecules is common to respiration-mediated breakdown of fats, carbohydrates and proteins? (a) Glucose-6-phosphate (b) Fructose 1, 6-bisphosphate (c) Pyruvic acid (d) Acetyl CoA 19 A few drops of sap were collected by cutting across a plant stem by a suitable method The sap was tested chemically Which one of the following test results indicates that it is phloem sap? (a) Acidic (b) Alkaline (c) Low refractive index (d) Absence of sugar 20 You are given a tissue with its potential for differentiation in an artificial culture Which of the following pairs of hormones would you add to the medium to secure shoots as well as roots? (a) IAA and gibberellin (b) Auxin and cytokinin (c) Auxin and abscisic acid (d) Gibberellin and abscisic acid 21 Phytochrome is a (a) flavoprotein (c) lipoprotein (b) glycoprotein (d) chromoprotein 22 Which is essential for the growth of root tip? (a) Zn (b) Fe (c) Ca (d) Mn 23 The process which makes major difference between C3 and C4 plants is (a) glycolysis (b) Calvin cycle (c) photorespiration (d) respiration 24 Which one of the following statements is not correct? (a) Offspring produced by the asexual reproduction are called clone (b) Microscopic, motile, asexual reproductive structures are called zoospores (c) In potato, banana and ginger, the plantlets arise from, the internodes present in the modified stem (d) Water hyacinth, growing in the standing water, drains oxygen from water that leads to the death of fishes 25 Which one of the following generates new genetic combinations leading to variation? (a) Vegetative reproduction (b) Parthenogenesis (c) Sexual reproduction (d) Nucellar polyembryony 26 Match column I with column II and select the correct option using the codes given below Column-I Column-II A Pistils fused together (i) Gametogenesis B Formation of gametes (ii) Pistillate C Hyphae of higher (iii) Syncarpous Ascomycetes D Unisexual female flower (iv) Dikaryotic (a) A-(iv), B-(iii), C-(i), D-(ii) (b) A-(ii), B-(i), C-(iv), D-(iii) (c) A-(i), B-(ii), C-(iv), D-(iii) (d) A-(iii), B-(i), C-(iv), D-(ii) 27 In majority of angiosperms (a) egg has a filiform apparatus (b) there are numerous antipodal cells (c) reduction division occurs in the megaspore mother cells (d) a small central cell is present in that embryo sac MT BIOLOGY TODAY SEPTEMBER ‘16 73 28 Pollination in water hyacinth and water lily is brought about by the agency of (a) water (b) insects or wind (c) birds (d) bats 39 Which kind of therapy was given in 1990 to a four-year-old girl with adenosine deaminase (ADA) deficiency? (a) Gene therapy (b) Chemotherapy (c) Immunotherapy (d) Radiation therapy 29 The ovule of an angiosperm is technically equivalent to (a) megasporangium (b) megasporophyll (c) megaspore mother cell (d) megaspore 40 How many hotspots of biodiversity in the world have been identified till date by Norman Myers? (a) 17 (b) 25 (c) 34 (d) 43 30 Taylor conducted the experiments to prove semi-conservative mode of chromosome replication on (a) Vinca rosea (b) Vicia faba (c) Drosophila melanogaster (d) E coli 31 The mechanism that causes a gene to move from one linkage group to another is called (a) inversion (b) duplication (c) translocation (d) crossing-over 32 The equivalent of a structural gene is (a) muton (b) cistron (c) operon (d) recon 33 A true breeding plant is (a) one that is able to breed on its own (b) produced due to cross-pollination among unrelated plants (c) near homozygous and produces offspring of its own kind (d) always homozygous recessive in its genetic constitution 34 Which of the following rRNAs acts as structural RNA as well as ribozyme in bacteria? (a) 5S rRNA (b) 18S rRNA (d) 5.8S rRNA (c) 23S rRNA 35 Stirred-tank bioreactors have been designed for (a) purification of product (b) addition of preservatives to the product (c) availability of oxygen throughout the process (d) ensuring anaerobic conditions in the culture vessel 36 A foreign DNA and plasmid cut by the same restriction endonuclease can be joined to form a recombinant plasmid using (a) EcoRI (b) Taq polymerase (c) polymerase III (d) ligase 37 Which of the following is not a component of downstream processing? (a) Separation (b) Purification (c) Preservation (d) Expression 38 Which of the following restriction enzymes produces blunt ends? (a) Sal I (b) EcoRV (c) XhoI (d) HindIII 74 MT BIOLOGY TODAY SEPTEMBER ‘16 41 The primary producers of the deep-sea hydrothermal vent ecosystem are (a) green algae (b) chemosynthetic bacteria (c) blue-green algae (d) coral reefs 42 Which of the following is correct for r-selected species? (a) Large number of progeny with small size (b) Large number of progeny with large size (c) Small number of progeny with small size (d) Small number of progeny with large size 43 If ‘+’ sign is assigned to beneficial interaction, ‘–’ sign to detrimental and ‘O’ sign to neutral interaction, then the population interaction represented by ‘+’ ‘–’ refers to (a) mutualism (b) amensalism (c) commensalism (d) parasitism 44 Which of the following is correctly matched? (a) Aerenchyma – Opuntia (b) Age pyramid – Biome (c) Parthenium hysterophorus – Threat to biodiversity (d) Stratification – Population 45 Red list contains data or information on (a) all economically important plants (b) plants whose products are in international trade (c) threatened species (d) marine vertebrates only 46 Which of the following sets of diseases is caused by bacteria? (a) Cholera and tetanus (b) Typhoid and smallpox (c) Tetanus and mumps (d) Herpes and influenza 47 Match column I with column II for housefly classification and select the correct option using the codes given below Column-I Column-II A Family (i) Diptera B Order (ii) Arthropoda C Class (iii) Muscidae D Phylum (iv) Insecta (a) A-(iii), B-(i), C-(iv), D-(ii) (b) A-(iii), B-(ii), C-(iv), D-(i) (c) A-(iv), B-(iii), C-(ii), D-(i) (d) A-(iv), B-(ii), C-(i), D-(iii) 48 Choose the correct statement (a) All mammals are viviparous (b) All cyclostomes not possess jaws and paired fins (c) All reptiles have a three-chambered heart (d) All pisces have gills covered by an operculum 49 Study the four statements (A-D) given below and select the two correct ones out of them A Definition of biological species was given by Ernst Mayr B Photoperiod does not affect reproduction in plants C Binomial nomenclature system was given by R.H Whittaker D In unicellular organisms, reproduction is synonymous with growth The two correct statements are (a) B and C (b) C and D (c) A and D (d) A and B 50 In male cockroaches, sperms are stored in which part of the reproductive system? (a) Seminal vesicles (b) Mushroom glands (c) Testes (d) Vas deferens 51 Smooth muscles are (a) involuntary, fusiform, non-striated (b) voluntary, multinucleate, cylindrical (c) involuntary, cylindrical, striated (d) voluntary, spindle-shaped, uninucleate 52 Oxidative phosphorylation is (a) formation of ATP by transfer of phosphate group from a substrate to ADP (b) oxidation of phosphate group in ATP (c) addition of phosphate group to ATP (d) formation of ATP by energy released from electrons removed during substrate oxidation 53 Which of the following is the least likely to be involved in stabilising the three-dimensional folding of most proteins? (a) Hydrogen bonds (b) Electrostatic interaction (c) Hydrophobic interaction (d) Ester bonds 54 Which of the following describes the given graph correctly? 55 When cell has stalled DNA replication fork, which checkpoint should be predominantly activated? (a) G1/S (b) G2/M (c) M (d) Both G2/M and M 56 Match the stages of meiosis in column I to their characteristic features in column II and select the correct option using the codes given below Column-I Column-II A Pachytene (i) Pairing of homologous chromosomes B Metaphase I (ii) Terminalisation of chiasmata C Diakinesis (iii) Crossing-over takes place D Zygotene (iv) Chromosomes align at equatorial plate (a) A-(iii), B-(iv), C-(ii), D-(i) (b) A-(i), B-(iv), C-(ii), D-(iii) (c) A-(ii), B-(iv), C-(iii), D-(i) (d) A-(iv), B-(iii), C-(ii), D-(i) 57 Which hormones stimulate the production of pancreatic juice and bicarbonate? (a) Angiotensin and epinephrine (b) Gastrin and insulin (c) Cholecystokinin and secretin (d) Insulin and glucagon 58 The partial pressure of oxygen in the alveoli of the lungs is (a) equal to that in the blood (b) more than that in the blood (c) less than that in the blood (d) less than that of carbon dioxide 59 Choose the correct statement (a) Nociceptors respond to changes in pressure (b) Meissner’s corpuscles are thermoreceptors (c) Photoreceptors in the human eye are depolarised during darkness and become hyperpolarised in response to the light stimulus (d) Receptors not produce graded potentials 60 Graves’ disease is caused due to (a) hyposecretion of thyroid gland (b) hypersecretion of thyroid gland (c) hyposecretion of adrenal gland (d) hypersecretion of adrenal gland (a) Endothermic reaction with energy A in presence enzyme and B in absence of enzyme (b) Exothermic reaction with energy A in presence enzyme and B in absence of enzyme (c) Endothermic reaction with energy A in absence enzyme and B in presence of enzyme (d) Exothermic reaction with energy A in absence enzyme and B in presence of enzyme of of of of 61 Name the ion responsible for unmasking of active sites for myosin for cross-bridge activity during muscle contraction (a) Calcium (b) Magnesium (c) Sodium (d) Potassium 62 Name the blood cells, whose reduction in number can cause clotting disorder, leading to excessive loss of blood from the body (a) Erythrocytes (b) Leucocytes (c) Neutrophils (d) Thrombocytes MT BIOLOGY TODAY SEPTEMBER ‘16 75 63 Name a peptide hormone which acts mainly on hepatocytes, adipocytes and enhances cellular glucose uptake and utilisation (a) Insulin (b) Glucagon (c) Secretin (d) Gastrin 64 Osteoporosis, an age-related disease of skeletal system, may occur due to (a) immune disorder affecting neuromuscular junction leading to fatigue (b) high concentration of Ca++ and Na+ (c) decreased level of estrogen (d) accumulation of uric acid leading to inflammation of joints 65 Serum differs from blood in (a) lacking globulins (b) lacking albumins (c) lacking clotting factors (d) lacking antibodies 66 Lungs not collapse between breaths and some air always remains in the lungs which can never be expelled because (a) there is a negative pressure in the lungs (b) there is a negative intrapleural pressure pulling at the lung walls (c) there is a positive intrapleural pressure (d) pressure in the lungs is higher than the atmospheric pressure 67 The posterior pituitary gland is not a ‘true’ endocrine gland because (a) it is provided with a duct (b) it only stores and releases hormones (c) it is under the regulation of hypothalamus (d) it secretes enzymes 68 The part of nephron involved in active reabsorption of sodium is (a) distal convoluted tubule (b) proximal convoluted tubule (c) Bowman’s capsule (d) descending limb of Henle’s loop 69 Which of the following is hormone-releasing IUD? (a) LNG-20 (b) Multiload 375 (c) Lippes loop (d) Cu7 70 Which of the following is incorrect regarding vasectomy? (a) No sperm occurs in seminal fluid (b) No sperm occurs in epididymis (c) Vasa deferentia is cut and tied (d) Irreversible sterility 71 Embryo with more than 16 blastomeres formed due to in vitro fertilisation is transferred into (a) uterus (b) Fallopian tube (c) fimbriae (d) cervix 76 MT BIOLOGY TODAY SEPTEMBER ‘16 72 Which of the following depicts the correct pathway of transport of sperms? (a) Rete testis → Efferent ductules → Epididymis → Vas deferens (b) Rete testis → Epididymis → Efferent ductules → Vas deferens (c) Rete testis → Vas deferens → Efferent ductules → Epididymis (d) Efferent ductules → Rete testis → Vas deferens → Epididymis 73 Match column I with column II and select the correct option using the codes given below Column-I Column-II A Mons pubis (i) Embryo formation B Antrum (ii) Sperm C Trophectoderm (iii) Female external genitalia D Nebenkern (iv) Graafian follicle (a) A-(iii), B-(iv), C-(ii), D-(i) (b) A-(iii), B-(iv), C-(i), D-(ii) (c) A-(iii), B-(i), C-(iv), D-(ii) (d) A-(i), B-(iv), C-(iii), D-(ii) 74 Several hormones like hCG, hPL, estrogen, progesterone are produced by (a) ovary (b) placenta (c) Fallopian tube (d) pituitary 75 If a colour-blind man marries a woman who is homozygous for normal colour vision, the probability of their son being colour-blind is (a) (b) 0.5 (c) 0.75 (d) 76 Genetic drift operates in (a) small isolated population (b) large isolated population (c) non-reproductive population (d) slow reproductive population 77 In Hardy-Weinberg equation, the frequency of heterozygous individual is represented by (a) p2 (b) 2pq (c) pq (d) q2 78 The chronological order of human evolution from early to the recent is (a) Australopithecus → Ramapithecus → Homo habilis → Homo erectus (b) Ramapithecus → Australopithecus → Homo habilis → Homo erectus (c) Ramapithecus → Homo habilis → Australopithecus → Homo erectus (d) Australopithecus → Homo habilis → Ramapithecus → Homo erectus 79 Which of the following is the correct sequence of events in the origin of life? I Formation of protobionts II Synthesis of organic monomers III IV (a) (c) Synthesis of organic polymers Formation of DNA-based genetic systems I, II, III, IV (b) I, III, II, IV II, III, I, IV (d) II, III, IV, I 80 A molecule that can act as a genetic material must fulfill the traits given below, except (a) it should be able to express itself in the form of ‘Mendelian characters’ (b) it should be able to generate its replica (c) it should be unstable structurally and chemically (d) it should provide the scope for slow changes that are required for evolution 81 DNA-dependent RNA polymerase catalyses transcription on one strand of the DNA which is called the (a) template strand (b) coding strand (c) alpha strand (d) antistrand 82 Interspecific hybridisation is the mating of (a) animals within same breed without having common ancestors (b) two different related species (c) superior males and females of different breeds (d) more closely related individuals within same breed for 4-6 generations 83 Which of the following is correct regarding AIDS causative agent HIV? (a) HIV is enveloped virus containing one molecule of single-stranded RNA and one molecule of reverse transcriptase (b) HIV is enveloped virus that contains two identical molecules of single-stranded RNA and two molecules of reverse transcriptase (c) HIV is unenveloped retrovirus (d) HIV does not escape but attacks the acquired immune response 84 Among the following edible fishes, which one is a marine fish having rich source of omega-3 fatty acids? (a) Mystus (b) Mangur (c) Mrigala (d) Mackerel 85 Match column I with column II and select the correct option using the codes given below Column-I Column-II A Citric acid (i) Trichoderma B Cyclosporin A (ii) Clostridium C Statins (iii) Aspergillus D Butyric acid (iv) Monascus (a) A-(iii), B-(i), C-(ii), D-(iv) (b) A-(iii), B-(i), C-(iv), D-(ii) (c) A-(i), B-(iv), C-(ii), D-(iii) (d) A-(iii), B-(iv), C-(i), D-(ii) 86 Biochemical Oxygen Demand (BOD) may not be a good index for pollution for water bodies receiving effluents from (a) domestic sewage (c) petroleum industry (b) dairy industry (d) sugar industry 87 The principle of competitive exclusion was stated by (a) C Darwin (b) G.F Gause (c) MacArthur (d) Verhulst and Pearl 88 Which of the following National Parks is home to the famous musk deer or hangul? (a) Keibul Lamjao National Park, Manipur (b) Bandhavgarh National Park, Madhya Pradesh (c) Eaglenest Wildlife Sanctuary, Arunachal Pradesh (d) Dachigam National Park, Jammu and Kashmir 89 A lake which is rich in organic waste may result in (a) increased population of aquatic organisms due to minerals (b) drying of the lake due to algal bloom (c) increased population of fish due to lots of nutrients (d) mortality of fish due to lack of oxygen 90 The highest DDT concentration in aquatic food chain shall occur in (a) phytoplankton (b) seagull (c) crab (d) eel ANSWER KEY 11 16 21 26 31 36 41 46 51 56 61 66 71 76 81 86 (b) (b) (a) (a) (d) (d) (c) (d) (b) (a) (a) (a) (a) (b) (a) (a) (a) (c) 12 17 22 27 32 37 42 47 52 57 62 67 72 77 82 87 (b) (b) (c) (a) (c) (c) (b) (d) (a) (a) (d) (c) (d) (b) (a) (b) (b) (b) 13 18 23 28 33 38 43 48 53 58 63 68 73 78 83 88 (a) (b) (b) 14 (d) 19 (c) 24 (b) 29 (c) 34 (b) 39 (d) 44 (b) 49 (d) 54 (b) 59 (a) 64 (b) 69 (b) 74 (b) 79 (b & d) 84 (d) 89 (d) (a) (b) (b) (c) (a) (c) (a) (c) (c) (b) (c) (c) (a) (b) (c) (d) (d) 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 (c) (a) (b) (b) (c) (b) (c) (c) (c) (a) (b) (b) (c) (b) (a) (c) (b) (b)  JULY 2016 COLEORHIZA FETOSCOPY HOLOCENE VARIEGATION ASPERMIA BRACTEOLE ICHTHYOSTEGA ROTENONES PREBIOTIC 10 QUARANTINE Winners : Debasrija Mondal (West Bengal), Saikat Mukherjee (West Bengal), Bindu Naik (Tamil Nadu), Shiveha Verma (New Delhi), Shubhra Mandal (Kolkata) MT BIOLOGY TODAY SEPTEMBER ‘16 77