NEET AIPMT Biology Chapter Wise Solutions – Solved Paper NEET 2016 (Phase – 2)
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NEET AIPMT Biology Chapter Wise SolutionsPhysicsChemistry
The Living World
1. Nomenclature is governed by certain universal rules. Which one of the following is contrary to the rules of nomenclature?
(a) The names are written in Latin and are italicised.
(b) When written by hand the names are to be underlined.
(c) Biological names can be written in any language.
(d) The first word in a biological name represents the genus name and the second is a specific epithet. Biological Classification
2. The primitive prokaryotes responsible for the production of biogas from the dung of ruminant animals, include the
(a) methanogens
(b) eubacteria
(c) halophiles
(d) thermoacidophiles.
3. Which one of the following statements is wrong?
(a) Eubacteria are also called false bacteria.
(b) Phycomycetes are also called algal fungi.
(c) Cyanobacteria are also called blue-green algae.
(d) Golden algae are also called desmids.
4. Which of the following statements is wrong for viroids?
(a) They cause infections.
(b) Their RNA is of high molecular weight.
(c) They lack a protein coat.
(d) They are smaller than viruses.
5. One of the major components of cell wall of most fungi is
(a) cellulose
(b) hemicellulose
(c) chitin
(d) peptidoglycan.
6. Chrysophytes, Euglenoids, Dinoflagellates and Slime moulds are included in the kingdom
(a) Fungi
(b) Animalia
(c) Monera
(d) Protista.
Plant Kingdom
7. Select the correct statement.
(a) Sequoia is one of the tallest trees.
(b) The leaves of gymnosperms are not well adapted to extremes of climate.
(c) Gymnosperms are both homosporous and heterosporous.
(d) Salvinia, Ginkgo and Pinus all are gymnosperms.
8. In bryophytes and pteridophytes, transport of male gametes requires
(a) birds
(b) water
(c) wind
(d) insects.
Animal Kingdom
9. Which one of the following characteristics is not shared by birds and mammals?
(a) Viviparity
(b) Warm blooded nature
(c) Ossified endoskeleton
(d) Breathing using lungs
10. Which of the following characteristic features always holds true for the corresponding group of animals?
11. Which of the following features is not present in the Phylum Arthropoda?
(a) Parapodia
(b) Jointed appendages
(c) Chitinous exoskeleton
(d) Metameric segmentation
Morphology of Flowering Plants
12. Which of the following is not a stem modification?
(a) Tendrils of cucumber
(b) Flattened structures of Opuntia
(c) Pitcher of Nepenthes
(d) Thorns of citrus
13. Stems modified into flat green organs performing the functions of leaves are known as
(a) phylloclades
(b) scales
(c) cladodes
(d) phyllodes.
14. Cotyledon of maize grain is called
(a) coleoptile
(b) scutellum
(c) plumule
(d) coleorhiza.
15. Tricarpellary, syncarpous gynoecium is found in flowers of
(a) Fabaceae
(b) Poaceae
(c) Liliaceae
(d) Solanaceae.
16. The standard petal of a papilionaceous corolla is also called
(a) vexillum
(b) corona
(c) carina
(d) pappus.
Anatomy of Flowering Plants
17. Specialised epidermal cells surrounding the guard cells are called
(a) bulliform cells
(b) lenticels
(c) complementary cells
(d) subsidiary cells.
Structural Organisation in Animals
18. Which type of tissue correctly matches with its location?
19. Which of the following features is not present in Periplaneta americana?
(a) Exoskeleton composed of N-acetylglucos- amine
(b) Metamerically segmented body
(c) Schizocoelom as body cavity
(d) Indeterminate and radial cleavage during embryonic development
Cell: The Unit of Life
20. Mitochondria and chloroplast are
(A) semi-autonomous organelles
(B) formed by division of pre-existing organelle! and they contain DNA but lack proteir synthesising machinery.
Which one of the following options is correct?
(a) (A) is true but (B) is false.
(b) Both (A) and (B) are false.
(c) Both (A) and (B) are correct.
(d) (B) is true but (A) is false.
21. Microtubules are the constituents of
(a) centrioles, spindle fibres and chromatin
(b) centrosome, nucleosome and centrioles
(c) cilia, flagella and peroxisomes
(d) spindle fibres, centrioles and cilia.
22. Which one of the following cell organelles is enclosed by a single membrane?
(a) Lysosomes
(b) Nuclei
(c) Mitochondria
(d) Chloroplasts
Biomolecules
23. A typical fat molecule is made up of
(a) one glycerol and one fatty acid molecule
(b) three glycerol and three fatty acid molecules
(c) three glycerol molecules and one fatty acid molecule
(d) one glycerol and three fatty acid molecules.
24. Which one of the following statements is wrong?
(a) Uracil is a pyrimidine.
(b) Glycine is a sulphur containing amino acid.
(c) Sucrose is a disaccharide.
(d) Cellulose is a polysaccharide.
Cell Cycle and Cell Division
25. Spindle fibres attach on to
(a) centromere of the chromosome
(b) kinetosome of the chromosome
(c) telomere of the chromosome
(d) kinetochore of the chromosome.
26. Which of the following is not a characteristic feature during mitosis in somatic cells?
(a) Chromosome movement
(b) Synapsis
(c) Spindle fibres
(d) Disappearance of nucleolus
27. In meiosis crossing over is initiated at
(a) zygotene
(b) diplotene
(c) pachytene
(d) leptotene.
Mineral Nutrition
28. In which of the following all three are macronutrients?
(a) Molybdenum, magnesium, manganese
(b) Nitrogen, nickel, phosphorus
(c) Boron, zinc, manganese
(d) Iron, copper, molybdenum
Photosynthesis in Higher Plants
29. Water vapour comes out from the plant leaf through the stomatal opening. Through the same stomatal opening carbon dioxide diffuses into j the plant during photosynthesis. Reason out the above statements using one of following options.
(a) The above processes happen only during night time.
(b) One process occurs during day time and the other at night.
(c) Both processes cannot happen simultaneously.
(d) Both processes can happen together because the diffusion coefficient of water and CO2 is different.
30. In a chloroplast the highest number of protons are found in
(a) intermembrane space
(b) antennae complex
(c) stroma
(d) lumen of thylakoids.
31. Emerson’s enhancement effect and Red drop have been instrumental in the discovery of
(a) photophosphorylation and cyclic electron transport
(b) oxidative phosphorylation
(c) photophosphorylation and non-cyclic electron transport
(d) two photosystems operating simultaneously.
32. 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?
(a) CAM
(b) Nitrogen fixer
(c) C3
(d) C4
33. Water soluble pigments found in plant cell vacuoles are
(a) carotenoids
(b) anthocyanins
(c) xanthophylls
(d) chlorophylls.
Plant Growth and Development
34. The Avena curvature is used for bioassay of
(a) IAA
(b) ethylene
(c) ABA
(d) GA3.
Digestion and Absorption
35. Which of the following guards the opening of hepatopancreatic duct into the duodenum?
(a) Pyloric sphincter
(b) Sphincter of Oddi
(c) Semilunar valve
(d) Ileocaecal valve
36. In the stomach, gastric acid is secreted by the
(a) peptic cells
(b) acidic cells
(c) gastrin secreting cells
(d) parietal cells.
Breathing and Exchange of Gases
37. Reduction in pH of blood will
(a) decrease the affinity of haemoglobin with oxygen
(b) release bicarbonate ions by the liver
(c) reduce the rate of heart beat
(d) reduce the blood supply to the brain.
38. Name the chronic respiratory disorder caused mainly by cigarette smoking.
(a) Respiratory acidosis
(b) Respiratory alkalosis
(c) Emphysema
(d) Asthma
39. Asthma may be attributed to
(a) inflammation of the trachea
(b) accumulation of fluid in the lungs
(c) bacterial infection of the lungs
(d) allergic reaction of the mast cells in the lungs.
Body Fluids and Circulation
40. Blood pressure in the pulmonary artery is
(a) more than that in the pulmonary vein
(b) less than that in the venae cavae
(c) same as that in the aorta
(d) more than that in the carotid.
Locomotion and Movement
41. In mammals, which blood vessel would normally carry largest amount of urea?
(a) Hepatic Vein
(b) Hepatic Portal Vein
(c) Renal Vein
(d) Dorsal Aorta
42. Lack of relaxation between successive stimuli in sustained muscle contraction is known as
(a) tetanus
(b) tonus
(c) spasm
(d) fatigue.
Neural Control and Coordination
43. Photosensitive compound in human eye is made up of
(a) opsin and retinol
(b) transducin and retinene
(c) guanosine and retinol
(d) opsin and retinal.
Chemical Coordination and Integration
44. Which of the following pairs of hormones are not antagonistic (having opposite effects) to each other?
(a) Aldosterone Atrial Natriuretjc Factor
(b) Relaxin Inhibin
(c) Parathormone Calcitonin
(d) Insulin Glucagon
45. The amino acid tryptophan is the precursor for the synthesis of
(a) estrogen and progesterone
(b) cortisol and cortisone
(c) melatonin and serotoriin
(d) thyroxine and triiodothyronine.
46. The coconut water from tender coconut represents
(a) free nuclear proembryo
(b) free nuclear endosperm
(c) endocarp
(d) fleshy mesocarp.
47. Which one of the following statements is not true?
(a) Pollen grains of many species cause severe allergies.
(b) Stored pollen in liquid nitrogen can be usee in the crop breeding programmes.
(c) Tapetum helps in the dehiscence of anther.
(d) Exine of pollen grains is made up c sporopollenin.
48. Seed formation without fertilisation in flowering plants involves the process of
(a) somatic hybridisation
(b) apomixis
(c) sporulation
(d) budding.
49. Which of the following statements is not correct?
(a) Pollen germination and pollen tube growth are regulated by chemical components of pollen interacting with those of the pistil.
(b) Some reptiles have also been reported as pollinators in some plant species.
(c) 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.
(d) Insects that consume pollen or nectar without bringing about pollination are called pollen/ nectar robbers.
50. Proximal end of the filament of stamen is attached to the
(a) placenta
(b) thalamus or petal
(c) anther
(d) connective.
Human Reproduction
51. Changes in GnRH pulse frequency in females is controlled by circulating levels of
(a) progesterone only
(b) progesterone and inhibin
(c) estrogen and progesterone
(d) estrogen and inhibin.
52. Fertilisation in humans is practically feasible only if
(a) the ovum and sperms are transported simultaneously to ampullary-isthmic junction of the cervix
(b) the sperms are transported into cervix within 48 hrs of release of ovum in uterus
(c) the sperms are transported into vagina just after the release of ovum in Fallopian tube
(d) the ovum and sperms are transported simultaneously to ampullary-isthmic junction of the Fallopian tube.
53. Select the incorrect statement.
(a) LH and FSH decrease gradually during the follicular phase.
(b) LH triggers secretion of androgens from the Leydig cells.
(c) FSH stimulates the sertoli cells which help in spermiogenesis.
(d) LH triggers ovulation in ovary.
54. Identify the correct statement on ‘inhibin’.
(a) Is produced by granulosa cells in ovary and inhibits the secretion of LH
(b) Is produced by nurse cells in testes and inhibits the secretion of LH
(c) Inhibits the secretion of LH, FSH and prolactin
(d) Is produced by granulosa cells in ovary and inhibits the secretion of FSH ,
Reproductive Health
55. Which of the following approaches does not give the defined action of contraceptive?
56. In context of amniocentesis, which of the following statements is incorrect?
(a) It can be used for detection of Down’s syndrome.
(b) It can be used for detection of cleft palate.
(c) It is usually done when a woman is between 14-16 weeks pregnant.
(d) It is used for prenatal sex determination.
Principles of Inheritance and Variation
57. 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
(a) somaclonal variation
(b) polyteny
(c) aneuploidy
(d) polyploidy.
58. Pick out the correct statements.
(1) Haemophilia is a sex-linked recessive disease.
(2) Downs syndrome is due to aneuploidy.
(3) Phenylketonuria is an autosomal recessive gene disorder.
(4) Sickle cell anaemia is an X-linked recessive gene disorder.
(a) (1), (3) and (4) are correct.
(b) (1), (2) and (3) are correct.
(c) (1) and (4) are correct.
(d) (2) and (4) are correct.
59. A tall true breeding garden pea plant is crossed with a dwarf true breeding garden pea plant. When the F, plants were selfed thp resulting genotypes were in the ratio of
(a) 3:1:: Tall: Dwarf
(b) 3:1:: Dwarf: Tall
(c) 1:2:1:: Tall homozygous: Tall heterozygous : Dwarf
(d) 1:2:1:: Tall heterozygous: Tall homozygous : Dwarf
60. Match the terms in column I with their description in column II and choose the correct
61. In a test cross involving F, dihybrid flies, more parental-type offspring were produced than the recombinant-type offspring. This indicates
(a) the two genes are linked and present on the same chromosome
(b) both of the characters are controlled by more than one gene
(c) the two genes are located on two different chromosomes
(d) chromosomes failed to separate during j meiosis.
62. Which of the following most appropriately describes haemophilia?
(a) Chromosomal disorder
(b) Dominant gene disorder
(c) Recessive gene disorder
(d) X-linked recessive gene disorder
Molecular Basis of Inheritance
63. Which one of the following is the starter codon?
(a) UAA
(b) UAG
(c) AUG
(d) UGA
64. Which of the following is required as inducer (s) for the expression of Lac operon?
(a) Lactose
(b) Lactose and Galactose
(c) Glucose
(d) Galactose
65. A complex of ribosomes attached to a single strand of RNA is known as
(a) polypeptide
(b) okazaki fragment
(c) polysome
(d) polymer.
Evolution
66. Which of the following structures is homologus to the wing of a bird?
(a) Hindlimb of rabbit
(b) Flipper of whale
(c) Dorsal fin of a shark
(d) Wing of a moth
67. Analogous structures are a result of
(a) shared ancestry
(b) stabilising selection
(c) divergent evolution
(d) convergent evolution.
68. Following are the two statements regarding the origin of life.
(A) The earliest organisms that appeared on the earth were non-green and presumably anaerobes.
(B) The first autotrophic organisms were the chemoautotrophs that never released oxygen.
Of the above statements which one of the following options is correct?
(a) Both (A) and (B) are correct.
(b) Both (A) and (B) are false.
(c) (A) is correct but (B) is false.
(d) (B) is correct but (A) is false.
Human Health and Diseases
69. Antivenom injection contains preformed antibodies while polio drops that are administered into the body contain
(a) gammaglobulin
(b) attenuated pathogens
(c) activated pathogens
(d) harvested antibodies.
70. Which of the following statements is not true for cancer cells in relation to mutations?
(a) Mutations inactivate the cell control.
(b) Mutations inhibit production of telomerase.
(c) Mutations in proto-oncogenes accelerate the cell cycle.
(d) Mutations destroy telomerase inhibitor.
71. In higher vertebrates, the immune system can distinguish self-cells and non-self. If this property is lost due to genetic abnormality and it attacks self-cells, then it leads to
(a) autoimmune disease
(b) active immunity
(c) allergic response
(d) graft rejection.
Strategies for Enhancement in Food Production
72. A system of rotating crops with legume or grass pasture to improve soil structure and fertility is called
(a) strip farming
(b) shifting agriculture
(c) ley farming
(d) contour farming.
Microbes in Human Welfare
73. Which of the following is wrongly matched in the given table?
Biotechnology : Principles and Processes
74. Which of the following is not a feature of the plasmids?
(a) Transferable
(b) Single-stranded
(c) Independent replication
(d) Circular structure
75. The Taq polymerase enzyme is obtained from
(a) Bacillus subtilis
(b) Pseudomonas putida
(c) Thermus aquaticus
(d) Thiobacillusferroxidans.
76. Which of the following is a restriction endonuclease?
(a) DNase I
(b) RNase
(c) Hind ll
(d) Protease
77. Which of the following is not required for any of the techniques of DNA fingerprinting available at present?
(a) Restriction enzymes
(b) DNA-DNA hybridisation
(c) Polymerase chain reaction
(d) Zinc finger analysis
Biotechnology and its Applications
78. The two polypeptides of human insulin are linked together by
(a) covalent bond
(b) disulphide bridges
(c) hydrogen bonds
(d) phosphodiester bond.
79. Which part of the tobacco plant is infected by Meloidogyne incognita?
(a) Stem
(b) Root
(c) Flower
(d) Leaf
Organisms and Populations
80. It is much easier for a small animal to run uphill than for a large animal, because
(a) small animals have a lower 02 requirement
(b) the efficiency of muscles in large animals is less than in the small animals
(c) it is easier to carry a small body weight
(d) smaller animals have a higher metabolic rate.
81. When does the growth rate of a’ population following the logistic model equal zero? The logistic model is given as dN/dt = rN(l-N/K)
(a) when N/K equals zero
(b) when death rate is greater than birth rate
(c) when N/K is exactly one
(d) when N nears the carrying capacity of the habitat.
82. Gauses principle of competitive exclusion states that
(a) no two species can occupy the same niche indefinitely for the same limiting resources
(b) larger organisms exclude smaller ones through competition
(c) more abundant species will exclude the less abundant species through competition
(d) competition for the same resources exclude species having different food preferences.
Ecosystem
83. Which of the following would appear as the pioneer organisms on bare rocks?
(a) Mosses
(b) Green algae
(c) Lichens
(d) Liverworts
84. Which one of the following is a characteristic feature of cropland ecosystem?
(a) Absence of weeds
(b) Ecological succession
(c) Absence of soil organisms
(d) Least genetic diversity
85. The term ecosystem was coined by
(a) E. Haeckel
(b) E.Warming
(c) E.P. Odum
(d) A. G. Tansley.
Biodiversity and Conservation
86. Which is the National Aquatic Animal of India?
(a) Blue whale
(b) Sea-horse
(c) Gangetic shark
(d) River dolphin
87. Which of the following is the most important cause of animals and plants being driven to extinction?
(a) Habitat loss and fragmentation
(b) Co-extinctions
(c) Over-exploitation
(d) Alien species invasion
Environmental Issues
88. Depletion of which gas in the atmosphere can lead to an increased incidence of skin cancers?
(a) Ammonia
(b) Methane
(c) Nitrous oxide
(d) Ozone
89. Joint Forest Management Concept was introduced in India during
(a) 1980s
(b) 1990s
(c) 1960s
(d) 1970s.
90. A river with an inflow of domestic sewage rich in organic waste may result in
(a) an increased production of fish due to biodegradable nutrients
(b) death of fish due to lack of oxygen
(c) drying of the river very soon due to algal bloom
(d) increased population of aquatic food web organisms.
1. (c)
Biological names are derived either from Latin language or are latinised. This is because Latin language is a dead language and therefore it will not change in form or spellings with the passage of time.
2. (a)
Methanogens are obligate anaerobes found in oxygen deficient environments such as marshes, swamps, sludge (formed during sewage treatment) and digestive systems of ruminants. Mostly they obtain their energy by reducing carbon dioxide and oxidising hydrogen with the production of methane. Eg., Methanobacillus and Methanothrix.
3. (a)
Eubacteria are also called true bacteria.
4. (b)
RNA of viroid has low molecular weight.
5. (c)
Fungal cell wall contains chitin or fungal cellulose along with other polysaccharides, proteins, lipids and a number of other substances.
6. (d)
Protista is a kingdom of unicellular eukaryotic organisms. Itincludesphotosyntheticprotists(dinoflagellates, chrysophytes and euglenoids), consumer-decomposer protists (slime moulds) and protozoan protists.
7. (a)
Sequoia sempervirens is the tallest gymnosperm. The leaves of gymnosperms are well adapted to extremes of climate. This is the reason for gymnosperm to flourish in cold areas where instead of rain, snow is the source of water. Gymnosperms are heterosporous i.e„ produce two different kinds of spores-microspores and megaspores. Salvinia is an aquatic pteridophyte.
8. (b)
The sperms of bryophytes and pteridophytes are flagellated and hence require an external supply of water to reach archaegonia.
9. (a)
All birds are oviparous while all mammals except Ornithorhyncus (duck billed platypus) and Echidna or Tachyglossus (spiny anteater) are viviparous.
10. (c)
PhylumChordataincludesbothjawlessvertebrates (Agnatha) and jawed vertebrates (Gnathostomata). Crocodile of Class Reptilia has four chambered heart with two auricles and two ventricles. Duck billed platypus and spiny anteater are oviparous mammals.
11. (a)
Parapodia are flattened, fleshy, vertical flap¬like outgrowths of body wall found in annelids on lateral sides of trunk segments. These are hollow structures enclosing coelom which is continuous with that of trunk segments. These serve the dual purpose of locomotion and respiration.
12. (c)
Pitcher of Nepenthes is a modification of leaf. In Nepenthes, the pitchers are meant for catching and digesting insects. The lamina is modified into pitcher. The leaf apex gives rise to a coloured lid for attracting the insects.
13. (a)
Phylloclades are flattened green stems which have taken over the function of photosynthesis while cladodes are only the branches of stem that are modified to take over the function of leaves. Cladodes may not be flattened as in Ruscus aculeatus, cladodes are leaf-like with spiny tip whereas in Asparagus, they are slightly flattened, fleshy, straight or curved pointed structures which develop in clusters in the axil of scale leaves.
14. (b)
15. (c)
Members of Liliaceae possess tricarpellary, syncarpous gynoecium with superior ovary. The ovary is trilocular with two to many ovules in each loculus.
16. (a)
The posterior large bilobed petal of a papilionaceous corolla is called standard or vexillum. It overlaps the two smaller lateral petals known as wings or alae.
17. (d)
The leaf and stem epidermis of plant is covered with pores called stomata. Each stomata is surrounded by a pair of specialised epidermal cells known as guard cells which are in some cases further surrounded by another category of less modified epidermal cells known as subsidiary cells which provide support to the guard cells.
18. (c)
Tip of nose has elastic cartilage. Simple columnar epithelium lines the stomach. Tendon is white fibrous connective tissue. Posterior part of intestine has single unit smooth muscle in which all fibres of muscle contract simultaneously as single unit.
19. (d)
In insect cleavage is superficial.
20. (a)
Both mitochondria and chloroplast are semi- autonomous organelles. They have their own DNA which produces its own, mRNA, fRNA and rRNA. These organelles also possess their own ribosomes and hence are able to synthesise some of their proteins.
21. (d)
Microtubules are unbranched hollow submicroscopic tubules of protein tubulin which develop on specific nucleating regions. It can undergo quick growth or dissolution at their ends by assembly or disassembly of monomers.
They are present in the cytoplasm as well as in specialised structures like centrioles, basal bodies, cilia or flagella, sensory hair, equatorial ring of thrombocytes, spindle apparatus, chromosome fibres, nerve processes, sperm tails, axostyle of parasitic flagellates, fibre system of Stentor, cyto- pharyngeal basket of Nassula, etc.
22. (a)
Lysosomes are small vesicles bounded by a single membrane and contain, hydrolytic enzymes. Nucleus, mitochondria and chloroplasts are double membrane bound cells organelles.
23. (d)
Neutral or true fats are triglycerides which are formed by esterification of three molecules of fatty acids with one molecule of trihydric alcohol, glycerol (glycerine or trihydroxy propane).
24. (b)
Glycine is a neutral amino acid. Cysteine and methionine are sulphur containing amino acid.
25. (d)
Small disc-shaped structures at the surface of the centromeres are called kinetochores. These structures serve as the sites of attachment of spindle fibres to the chromosomes that are moved into position at the centre of the cell.
26. (b)
Synapsis is the process of association of homologous chromosomes. It takes place during zygotene stage of prophase I of meiosis. This stage is not seen during mitosis.
27. (c)
Crossing over is a process of exchange of genetic material or chromatid segments between two homologous chromosomes. It is initiated during pachytene stage of meiosis.
28.
(None of the options are correct.)
Macronutrients are essential elements which are present in easily detectable quantities, 1-10 mg per gram of dry weight. The macro nutrients include carbon, hydrogen, oxygen, nitrogen, phosphorous, sulphur, potassium, calcium and magnesium. Micro nutrients or trace elements, are needed in very small amounts (equal or less than 0.1 mg/ gm of dry matter). These include iron, manganese, copper, molybdenum, zinc, boron, chlorine and nickel.
29. (d)
30. (d)
31. (d)
Emerson et al. (1957) found that if light of shorter wavelengths was provided at the same time as the longer red wavelengths, photosynthesis was even faster than the sum of the two rates with either colour alone. This synergism or enhancement became known as the Emerson enhancement effect. Enhancement can be interpreted as the long red wavelengths helping out the shorter wavelengths, or as the short group helping out the long red wavelengths. The two separate groups of pigments or photosystems cooperate in photosynthesis and that such long red wavelengths are absorbed only by one photosystem, called photosystem I (PS I). The second photosystem, photosystem II (PS II), absorbs wavelengths shorter than 690 nm, and for maximum photosynthesis wavelengths absorbed by both systems must function together. The two photosystems normally cooperate to cause photosynthesis at all wavelengths shorter than 690 nm, because both photosystems absorb those wavelengths. The importance of Emerson’s work is that it suggested the presence of two distinct photosystems.
32. (d)
33. (b)
Anthocyanins are water soluble pigments, which commonly occur in membrane enclosed vacuoles. They are responsible for colour of fruits and flower petals.
34. (a)
Avena curvature test is a test based on the experiments of Went (1928) which can measure auxin upto 300 pg/litre. Indole 3-Acetic Acid (IAA) is a universal natural auxin and Avena curvature test may serve as an accurate bioassay for this plant hormone.
35. (b)
The sphincter of Oddi is a muscular valve that controls the flow of digestive juices (bile and pancreatic j uice) through the hepatopancreatic duct into the duodenum.
36. (d)
Parietal cells are large cells present on the side walls of the gastric glands. They lie against the basement membrane. They secrete hydrochloric acid and Castle’s intrinsic gastric factor that helps in the absorption of vitamin BJ2 in the ileum.
37. (a)
Reduction in pH of blood causes oxygen- haemoglobin dissociation curve to shift to right which indicates dissociation of oxygen from haemoglobin. This decreases affinity of haemoglobin for oxygen.
38. (c)
Emphysema is a chronic obstructive pulmonary disease (COPD) caused due to cigarette smoking. It is an inflation or abnormal distention of the bronchioles or alveolar sacs of the lungs which causes irreversible distension and loss of elasticity of alveoli of the lungs.
39. (d)
Asthma is an allergic condition in which the tissue surrounding the bronchioles of the lungs swell up and compress the bronchioles thus causing difficulty in breathing. This allergy mainly involves IgE antibodies and chemicals like histamine and serotonin from the mast cells.
40. (a)
41. (a)
Hepatic vein carries largest amount of urea. Urea is produced in liver. Hepatic vein transports liver’s deoxygenated blood to heart for oxygenation.
42. (a)
Tetanus refers to continued state of contraction of a muscle resulting from the summation of a series of rapid muscular contractions (twitches) that are induced by repeated stimulation of the muscle.
43. (d)
The rods contain a photosensitive pigment called the rhodopsin. Rhodopsin is composed of opsin and retinene. The opsin is a protein and is called scotopsin in rhodopsin. The retinene is an aldehyde of vitamin A and is called retinal.
44. (b)
Aldosterone is released from adrenal glands which induces distal convoluted tubule to absorb more Na+ and water. ANF inhibits the release of renin from juxtaglomerular apparatus (JGA) and thereby, inhibits NaCl reabsorption by the collecting duct and reduces aldosterone release from the adrenal gland.
Calcitonin is secreted when calcium level is high in the blood. It then lowers the calcium level by suppressing release of calcium ions from the bones. Parathormone is secreted when blood calcium level is too low. Parathyroid gland stops secreting PTH and brings calcium level back to the normal. Thus, calcitonin has an action opposite to that of the parathyroid hormone or parathormone on calcium metabolism.
Insulin lowers blood sugar level and glucagon raises blood sugar level. Relaxin hormone is secreted by ovary and placenta during pregnancy, which relaxes ligaments in pelvis and softens and widens cervix during childbirth. Inhibin secreted by granulosa cells in the ovaries inhibits secretion of FSH by anterior pituitary. Thus, relaxin and inhibin have different functions and are not antagonistic.
45. (c)
Tryptophan is an essential amino acid which is precursor for the synthesis of melatonin and serotonin.
46. (b)
Coconut has multicellular endosperm (called coconut meal) in the outer part and free nuclear as well as vacuolate endosperm (called coconut milk or coconut water) in the centre.
47. (c)
Tapetum is the innermost wall layer of microsporangium that nourishes developing pollen grains.
48. (b)
Apomixis is a reproductive process which does not involve gametic fusion. In apomictic flowering plants there is no fertilisation and embryos develop simply by division of a cell of ovule.
49. (c)
Pollen-pistil interaction is the group of events that occur from the time of pollen deposition over the stigma to the time of pollen tube entry into ovule. It is a safety measure to ensure that illegitimate crossing does not occur. Pollen grains of number of plants may settle over a stigma. The pollens belonging to same species would germinate while other fail to do so but the pollen tube of the compatible pollen will grow through the style to reach the ovule whereas growth of incompatible pollens will be arrested at stigmatic disc or sometimes in the beginning part of style.
50. (b)
51. (c)
GnRH is secreted by the hypothalamus which stimulates the anterior lobe of pituitary gland to secrete luteinising hormone (LH) and FSH. FSH stimulates the growth of the ovarian follicles and stimulates the formation of oestrogens. LFI stimulates the corpus luteum to secrete progesterone. Rising levels of progesterone and estrogen inhibits the release of GnRH, which, in turn, inhibits the production of FSH and LH.
52. (d)
The fusion of a haploid male gamete (sperm) and a haploid female gamete (ovum) to form a diploid zygote is called fertilisation. In human beings, it takes place in the ampullary isthmic junction of the oviduct (Fallopian tube).
53. (a)
During follicular phase FSH secretion increases. Follicular phase (proliferative phase) usually includes cycle days 6-13 or 14 in a 28 days cycle. The follicle stimulating hormone (FSH) secreted by the anterior lobe of the pituitary gland stimulates the ovarian follicle to secrete oestrogens.
54. (d)
55. (b)
Vasectomy is a sterilisation technique for the males in which a small part of the vas deferens is removed or tied up through a small cut on the scrotum to prevent passage of sperms. Spermatogenesis is the series of cell division in the testis that results in the production of spermatozoa or sperms.
56. (b)
Amniocentesis is foetal sex determination and disorder test based on the chromosomal pattern in the amniotic fluid surrounding the developing embryo. It can be used to determine the sex of the infant, to identify some abnormalities in the number of chromosomes and to detect certain biochemicals and enzymatic abnormalities. It is usually done when woman is 14-16 weeks pregnant. Cleft plate can be detected by ultrasound.
57. (d)
Polyploidy is the phenomenon of occurrence of more than two sets of chromosomes in the nucleus of a cell. Polyploidy is more common in plants. Polyploidy arises as a result of total nondisjunction of chromosomes during mitosis or meiosis.
58. (b)
Sickle-cell anaemia is an autosomal recessive genetic disorder. It can be transmitted from parents to the offspring when both the partners are carriers of the gene (or heterozygous).
59. (c)
When a tall true breeding garden pea plant is crossed with a dwarf true breeding garden pea plant and the F, plants were selfed the resulting genotypes were in the ratio of 1 : 2 : 1 i.e., Tall homozygous Tall heterozygous Dwarf
It can be illustrated as given below
60. (d)
61. (a)
If in a dihybrid test cross more parental combinations appear as compared to the recombinants in F2 generation, then it is indicative of involvement of linkage. Linkage is the tendency of two different genes on the same chromosome to remain together during the separation of homologous chromosomes at meiosis. During complete linkage no recombinants are formed whereas in incomplete linkage few recombinants are produced along with parental combinations.
62. (d)
Haemophilia is a sex-linked disease. It is genetically due to the presence of a recessive sex linked gene h, which is carried by X-chromosome.
63. (c)
Polypeptide synthesis is signalled by two initiator codons or start codons i.e., AUG (methionine codon) and rarely by GUG (valine codon).
64. (a)
In Lac operon, lactose is an inducer. It binds with suppressor and inactivates it. It allows RNA polfmers access to the promoter and transcription proceeds.
65. (c)
66. (b)
Homologous organs have same fundamental structure but different function. The wing of a bird and flipper of a whale are structurally forelimbs, which consist of humerus, radio-ulna, carpals, metacarpals and digits but they perform different function. The wings of birds help them to fly while flipper helps the whale to swim.
67. (d)
The organs which have similar functions but are different in their structural details and origin are called analogous organs. The analogous structures are the result of convergent evolution.
68. (a)
69. (b)
The Sabin vaccine or trivalent ‘oral polio vaccine’ consists of attenuated viral strains.
70. (b)
71. (a)
Autoimmunity is a disorder of the body’s defence mechanisms in which an immune response is elicited against its own tissues, which are thereby damaged or destroyed. Auto immunity may be caused due to genetic or environmental factors.
72. (c)
Ley farming is an agricultural system where the field is alternately seeded for grain and left fallow for growing hay or used for pasture. During the fallow/pasture period the soil is filled with roots of grasses and other plants. New ploughing mixes them in the soil and also increases the amount of nitrogen in the soil especially when legume forage are used. It also protects soil from erosion by maintaining constant soil coverage.
73. (b)
Clostridium butylicum helps in the production of butyric acid. Candida lipolytica and Geotrichum candidum help in production of lipases that are added in detergents for removing oily stains from laundry.
74. (b)
Plasmids are extra-chromosomal, self-replicating, usually circular, double-stranded DNA molecules that serve as vectors which carry foreign DNA segment and replicate inside host cell.
75. (c)
Taq polymerase, generally used in PCR is isolated from thermophilic bacterium 7hermus aquaticus.
76. (c)
Hind II is the first restriction endonuclease. It was isolated from Haemophilus influenzae Rd. It always cut DNA at specific position producing blunt ends. DNase I is an endonuclease that cleaves DNA preferentially at phosphodiester linkages adjacent to a pyrimidine nucleotide non-specially. RNAse is a type of nuclease that catalyses the degradation of RNA into smaller components. It can be endoribonuclease or exoribonuclease. A protease is an enzyme that perform proteolysis, i.e., protein catabolism by hydrolysis of the peptide bonds.
77. (d)
Any small, functional, freely folded domain in which coordination of one or more zinc ions is required to stabilise its structure is known as zinc finger. The zinc finger domains are widely dispersed in eukaryotic genomes and are actively involved in sequence specific binding to DNA/ RNA and contribute in protein-protein recognitions.
78. (b)
Human insulin is made up of 51 amino acids arranged in two polypeptide chains. Chain A has 21 amino acids and chain B has 30 amino acids. The two polypeptide chains are interconnected by disulphide bridges or S-S-linkages.
79. (b)
Meloidogyne incognita is a nematode which infects the roots of the tobacco plants and causes a great reduction in the yield.
80. (b)
The small animals have smaller surface area to body volume ratio. They have higher metabolic rates than larger animals. Therefore, it is much easier for small animals to move uphill than large animals.
81. (c)
82. (a)
Gause’s ‘competitive exclusion principle’ states that if resources are limited, then two closely related species competing for the same resource cannot co-exist indefinitely and the competitively inferior one will be eliminated eventually.
83. (c)
The bare rocky habitat is extremely hostile to living beings. There is no water, as the substratum does not absorb rain water. There is no nutrient holding mechanism. Plants cannot grow on these rocks. The first inhabitants or pioneers of such a habitat are usually lichens as they are resistant to desiccation and extreme temperatures.
84. (d)
Cropland ecosystem is an artificial or man-made terrestrial ecosystem which is created and maintained by human beings for their maximum benefits. Therefore, they will have least genetic diversity.
85. (d)
The term ecosystem was coined by A.G. Tansley in 1935.
86. (d)
River dolphin found in holy river Ganga, Brahmputra, Indus and its tributaries is the National aquatic animal of India. Presence of river dolphin in Ganga indicates pure and fresh water.
87. (a)
Destruction of natural habitat causes the most serious threat to the biodiversity. Over-population, urbanisation and industrialisation lead to the destruction or fragmentation of natural habitats to fulfill the requirement of additional land. Loss of habitat results in annihilation of plants, microorganisms and forcing out of animals which in alien lands die out after some time. Fragmentation of habitats results in disruption of complex interactions amongst species, destruction of species in the cleared regions, annihilation of species restricted to deeper undisturbed parts of forests and decreased biodiversity in the habitat fragments.
88. (d)
Ozone layer or shield is present in stratosphere. It functions as a shield against strong UV radiations coming from sun. UV radiations are very harmful and may cause mutations in living organisms. Thinning of ozone layer increases the amount of UV radiations reaching the earth. It would increase occurrence of cataract, skin cancers, dimming of eye sight, photoburning, deficient functioning of immune system, etc.
89. (a)
In India, Joint Forest Management was started in 1980s. Village and tribal communities are being involved in development and protection of degraded forests on share basis.
90. (b)
Domestic sewage is rich in biodegradable organic matter. When sewage is discharged into the river, it stimulates the activity of several decomposer microorganisms. Decomposition of organic matter by these microorganisms requires a lot of oxygen and results in sharp decline in dissolved oxygen content downstream from the point of sewage discharge. This causes death of fish and other aquatic creatures.
NEET AIPMT Biology Chapter Wise SolutionsPhysicsChemistry
1. Which of the following pairs is not correctly ma tched? (AlPMT 2015)
2. In ginger, vegetative propagation occurs through (AlPMT2015, Cancelled)
(a) bulbils
(b) runners
(c) rhizome
(d) offsets.
3. In oogamy, fertilization involves (2004)
(a) a small non-motile female gamete and a large motile male gamete
(b) a large non-motile female gamete and a small motile male gamete
(c) a large non-motile female gamete and a small non-motile male gamete
(d) a large motile female gamete and a small non- motile male gemete.
4. During regeneration, modification of an organ to other organ is known as (2001)
(a) morphogenesis
(b) epimorphosis
(c) morphallaxis
(d) accretionary growth.
5. The process of series of changes from larva to adult after embryonic development is called (1999)
(a) regeneration
(b) growth
(c) metamorphosis
(d) ageing.
6. ‘Nothing lives for ever, but life continues’. What does it mean? (1995)
(a) older die but new are produced due to reproduction
(b) nothing can produce without death
(c) death has nothing to do with the continuation of life
(d) parthenogenesis is must for sexual reproduction.
1. (a)
Sargassum is a brown alga. In brown algae, asexual reproduction occurs by means of spores and sexual reproduction varies from isogamy, anisogamy to oogamy.
2. (c)
The rhizome is a thickened, underground, dorsiventral stem that grows horizontally at a particular depth within the soil. It is brown in colour and shows cymose branching. It can be distinguished from the modified root by the presence of nodes, internodes, terminal buds, axillary buds and scale leaves. The rhizome are perennial and propagate vegetatively. They store food materials and appear tuberous. E.g., Zingiber officinale (ginger), Curcuma longa (turmeric), Canna indica.
3. (b)
Oogamy is the sexual reproduction involving the formation and subsequent fusion of a large, usually stationary, female gamete and a small motile male gamete. The female gamete may contain nourishment for the development of the embryo, which is often retained and protected by the parent organism.
4. (b)
There are two mechanisms of regeneration morphallaxis and epimorphosis.
(i) Morphallaxis. It involves the reconstruction of the whole body from a small fragment by reorganizing the existing cells. The regenerated organism is smaller than the original one, e.g., Amoeba. However, after the completion of the process it grows and attains normal size after some time.
(ii) Epimorphosis. It replaces a lost organ of the body by proliferating new cells from the surface of the wound or injured part. Regeneration of an appendage in an arthropod, arm in a starfish, and tail in a lizard occurs by the process of epimorphosis.
5. (c)
Metamorphosis is a process of series of changes of form from larva to adult after embryonic development. Regeneration is defined as replacement, repair or restoration of the lost or damaged structures or reconstitution of the whole body from a small fragment of it during the post-embryonic life of an organism. Growth is the result of greater anabolic (synthetic) processes over the catabolic (destructive) processes in the organism. Ageing may be defined as the progressive deterioration in the structure and functions of the cells, tissues and organs of an organism with the advancing age.
6. (a)
Death is a natural process by which the individuals die either naturally or due to illness, accident etc. But, before dying generally, individuals leave new individuals of their own kind through reproduction and thus the life continues.
NEET AIPMT Biology Chapter Wise SolutionsPhysicsChemistry
1. Filiform apparatus is characteristic feature of
(a) aleurone cell
(b) synergids
(c) generative cell
(d) nucellar embryo. (AIPMT 2015)
2. In angiosperms, microsporogenesis and mega- sporogenesis
(a) involve meiosis
(b) occur in ovule
(c) occur in anther
(d) form gametes without further divisions. (AIPMT 2015)
3. Flowers are unisexual in
(a) china rose
(b) onion
(c) pea
(d) cucumber. (AIPMT 2015)
4. Coconut water from a tender coconut is
(a) innermost layers of the seed coat
(b) degenerated nucellus
(c) immature embryo
(d) free nuclear endosperm. (AIPMT 2015)
5. Which one of the following fruits is parthenocarpic?
(a) Jackfruit
(b) Banana
(c) Brinjal
(d) Apple (AIPMT 2015)
6. Male gametophyte in angiosperms produces
(a) single sperm and two vegetative cells
(b) three sperms
(c) two sperms and a vegetative cell
(d) single sperm and a vegetative cell. (AIPMT 2015)
7. Which of the following are the important floral rewards to the animal pollinators ?
(a) Floral fragrance and calcium crystals
(b) Protein pellicle and stigmatic exudates
(c) Colour and large size of flower
(d) Nectar and pollen grains (AIPMT 2015, Cancelled)
8. Which one of the following may require pollinators, but is genetically similar to autogamy?
(a) Apogamy
(b) Cleistogamy
(c) Geitonogamy
(d) Xenogamy (AIPMT 2015, Cancelled)
9. Which one of the following statements is not true?
(a) The flowers pollinated by flies and bats secrete foul odour to attract them.
(b) Honey is made by bees by digesting pollen collected from flowers.
(c) Pollen grains are rich in nutrients, and they are used in the form of tablets and syrups.
(d) Pollen grains of some plants cause severe allergies and bronchial afflictions in some people. (AIPMT 2015, Cancelled)
10. The hilum is a scar on the
(a) fruit, where style was present
(b) seed, where micropyle was present
(c) seed, where funicle was attached
(d) fruit, where it was attached to pedicel. (AIPMT 2015, Cancelled)
11. Transmission tissue is characteristic feature of
(a) dry stigma
(b) wet stigma
(c) hollow style
(d) solid style. (AIPMT2015, Cancelled)
12. Which one of the following shows isogamy with non-flagellated gametes?
(a) Sargassum
(b) Ectocarpus
(c) Ulothrix
(d) Spirogyra (AIPMT 2014)
13. Geitonogamy involves
(a) fertilization of a flower by the pollen from another flower of the same plant
(b) fertilization of a flower by the pollen from the same flower
(c) fertilization of a flower by the pollen from a flower of another plant in the same population
(d) fertilization of a flower by the pollen from a flower of another plant belonging to a distant population. (AIPMT 2014)
14. An aggregate fruit is one which develops from
(a) multicarpellary syncarpous gynoecium
(b) multicarpellary apocarpus gynoecium
(c) complete inflorescence
(d) multicarpellary superior ovary. (AIPMT 2014)
15. Pollen tablets are available in the market for
(a) in vitro fertilization
(b) breeding programmes
(c) supplementing food
(d) ex situ conservation. (AIPMT2014)
16. Function of filiform apparatus is to
(a) recognize the suitable pollen at stigma
(b) stimulate division of generative cell
(c) produce nectar
(d) guide the entry of pollen tube. (AIPMT 2014)
17. Non-albuminous seed is produced in
(a) maize
(b) castor
(c) wheat
(d) pea. (AIPMT 2014)
18. Meiosis takes place in
(a) gemmule
(b) megaspore
(c) meiocyte
(d) conidia. (NEET 2013)
19. Seed coat is not thin, membranous in
(a) groundnut
(b) gram
(c) maize
(d) coconut. (NEET 2013)
20. Perisperm differs from endosperm in
(a) being a diploid tissue
(b) its formation by fusion of secondary nucleus with several sperms
(c) being a haploid tissue
(d) having no reserve food (NEET 2013)
21. Advantage of cleistogamy is
(a) no dependence on pollinators
(b) vivipary
(c) higher genetic variability
(d) more vigorous offspring. (NEET 2013)
22. Megasporangium is equivalent to
(a) nucellus
(b) ovule
(c) embryo sac
(d) fruit (NEET 2013)
23. Which one of the following statements is correct?
(a) Endothecium produces the microspores
(b) Tapetum nourishes the developing pollen
(c) Flard outer layer of pollen is called intine
(d) Sporogenous tissue is haploid (NEET2013)
24. Product of sexual reproduction generally generates
(a) new genetic combination leading to variation
(b) large biomass
(c) longer viability of seeds
(d) prolonged dormancy. (NEET 2013)
25. Animal vectors are required for pollination in
(a) Vallisneria
(b) mulberry
(c) cucumber
(d) maize. (Karnataka NEET 2013)
26. Albuminous seeds store their reserve food mainly in
(a) endosperm
(b) cotyledons
(c) hypocotyl
(d) perisperm. (Karnataka NEET 2013)
27. Megaspores are produced from the megaspore mother cells after
(a) mitotic division
(b) formation of thick wall
(c) differentiation
(d) meiotic division. (Karnataka NEET 2013)
28. Which one of the following statements is correct?
(a) Cleistogamous flowers are always autogamous.
(b) Xenogamy occurs only by wind pollination.
(c) Chasmogamous flowers do not open at all.
(d) Geitonogamy involves the pollen and stigma of flowers of different plants. (Karnataka NEET 2013)
29. Which of the following statements is correct?
(a) Sporopollenin can be degraded by enzymes.
(b) Sporopollenin is made up of inorganic materials.
(c) Sporopollenin can withstand high temperatures as well as strong acids and alkalis.
(d) Sporopollenin can withstand high temperatures but not strong acids. (Karnataka NEET2013)
30. Both, autogamy and geitonogamy are prevented in
(a) papaya
(b) cucumber
(c) castor
(d) maize. (Prelims 2012)
31. An organic substance that can withstand environmental extremes and cannot be degraded by any enzyme is
(a) cuticle
(b) sporopollenin
(c) lignin
(d) cellulose. (Prelims 2012)
32. Which one of the following is correctly matched?
(a) Onion-Bulb
(b) Ginger-Sucker
(c) Chlamydomonas-Conidia
(d) Yeast-Zoospores. (Prelims 2012)
33. Even in absence of pollinating agents seed-setting is assured in
fa) Commelina
(b) Zostera
(c) Salvia
(d) fig (Prelims 2012)
34. What is the function of germ pore?
(a) Emergence of radicle.
(b) Absorption of water for seed germination.
(c) Initiation of pollen tube.
(d) Release of male gametes. (Mains 2012)
35. Which one of the following statements is wrong?
(a) When pollen is shed at two-celled stage, double fertilization does not take place.
(b) Vegetative cell is larger than generative cell.
(c) Pollen grains in some plants remain viable for months.
(d) Intine is made up of cellulose and pectin. (Mains 2012)
36. Plants with ovaries having only one or a few ovules, are generally pollinated by
(a) bees
(b) butterflies
(c) birds
(d) wind. (Mains 2012)
37. Filiform apparatus is a characteristic feature of
(a) suspensor
(b) egg
(c) synergid
(d) zygote (Prelims 2011)
38. Nucellar polyembryony is reported in species of
(a) Citrus
(b) Gossypium
(c) Triticum
(d) Brassica (Prelims 2011)
39. Which one of the following pollinations is autogamous?
(a) geitonogamy
(b) xenogamy
(c) chasmogamy
(d) cleistogamy (Prelims 2011)
40. The “eyes” of the potato tuber are
(a) root buds
(b) flower buds
(c) shoot buds
(d) axillary buds (Prelims 2011)
41. Wind pollination is common in
(a) legumes
(b) lilies
(c) grasses
(d) orchids (Prelims 2011)
42. In angiosperms, functional megaspore develops into
(a) embryo sac
(b) ovule
(c) endosperm
(d) pollen sac (Mains 2011)
43. What is common between vegetative reproduction and apomixis?
(a) both are applicable to only dicot plants
(b) both bypass the flowering phase
(c) both occur round the year
(d) both produce progeny identical to the parent. (Mains 2011)
44. Apomictic embryos in Citrus arise from
(a) synergids
(b) maternal sporophytic tissue in ovule
(c) antipodal cells
(d) diploid egg. (Predims 2010)
45. Transfer of pollen grains from the anther to the stigma of another flower of the same plant is called
(a) xenogamy
(b) geitonogamy
(c) karyogamy
(d) autogamy. (Prelims 2010)
46. Wind pollinated flowers are
(a) small, brightly coloured, producing large number of pollen grains
(b) small, producing large number of dry pollen grains
(c) large producing abundant nectar and pollen
(d) small, producing nectar and dry pollen. (Prelims 2010)
47. Examine the figures (A-D) given below and select the right option out of (a – d), in which all the four structures A, B, C and D are identified correctly
48. Vegetative propagation in Pistia occurs by
(a) stolon
(b) offset
(c) runner
(d) sucker (Mains 2010)
49. Vegetative propagation in mint occurs by
(a) offset
(b) rhizome
(c) sucker
(d) runner (Prelims 2009)
50. Which one of the following pairs of plant structures has haploid number of chromosomes?
(a) nucellus and antipodal cells
(b) egg nucleus and secondary nucleus
(c) megaspore mother cell and antipodal cells
(d) egg cell and antipodal cells. (Prelims 2008)
51. What does the filiform apparatus do at the entrance into ovule?
(a) it brings about opening of the pollen tube
(b) it guides pollen tube from a synergid to egg
(c) it helps in the entry of pollen tube into a synergid
(d) it prevents entry of more than one pollen tube into the embryo sac. (Prelims 2008)
52. Unisexuality of flowers prevents
(a) geitonogamy, but not xenogamy
(b) autogamy and geitonogamy
(c) autogamy, but not geitonogamy
(d) both geitonogamy and xenogamy. (Prelims 2008)
53. Which one of the following is resistant to enzyme action?
(a) pollen exine
(b) leaf cuticle
(c) cork
(d) wood fibre. (Mains 2008)
54. Male gametes in angiosperms are formed by the division of
(a) generative cell
(b) vegetative cell
(c) microspore mother cell
(d) microspore. (2007)
55. Two plants can be conclusively said to belong to the same species if they
(a) have more than 90 per cent similar genes
(b) look similar and possess identical secondary metabolites
(c) have same number of chromosomes
(d) can reproduce freely with each other and form seeds. (2007)
56. Which one of the following is surrounded by a callose wall?
(a) male gamete
(b) egg
(c) pollen grain
(d) microspore mother cell. (2007)
57. Parthenocarpic tomato fruits can be produced by
(a) treating the plants with phenylmercuric acetate
(b) removing androecium of flowers before pollen grains are released
(c) treating the plants with low concentrations of gibberellic acid and auxins
(d) raising the plants from vernalized seeds (2006)
58. In a cereal grain the single cotyledon of embryo is represented by
(a) coleoptile
(b) coleorhiza
(c) scutellum
(d) prophyll (2006)
59. The arrangement of the nuclei in a normal embryo sac in the dicot plants is
(a) 3 + 3 + 2
(b) 2 + 4 + 2
(c) 3 + 2 + 3
(d) 2 + 3 + 3 (2006)
60. What type of placentation is seen in sweet pea?
(a) marginal
(b) basal
(c) axile
(d) free central (2006)
61. In which one pair both the plants can be vegetatively propagated by leaf species?
(a) Agave andKalanchoe
(b) Bryophyllum and Kalanchoe
(c) Asparagus and Bryophyllum
(d) Chrysanthemum and Agave. (2005)
62. In a type of apomixis known as adventive embryony, embryos develop directly from the
(a) nucellus or integuments
(b) zygote
fc) synergids or antipodals in an embryo sac
(d) accessory embryo sacs in the ovule. (2005)
63. Which one of the following represents an ovule, where the embryo sac becomes horse-shoe shaped and the funiculus and micropyle are close to each other?
(a) amphitropous
(b) circinotropous
(c) atropous
(d) anatropous. (2005)
64. Through which cell of the embryo sac, does the pollen tube enter the embryo sac?
(a) egg cell
(b) persistant synergid
(c) degenerated synergids
(d) central cell. (2005)
65. When a diploid female plant is crossed with a tetraploid male, the ploidy of endosperm cells in the resulting seed is
(a) tetraploidy
(b) pentaploidy
(c) diploidy
(d) triploidy. (2004)
66. An ovule which becomes curved so that the nucellus and embryo sac lie at right angles to the funicle is
(a) hemitropous
(b) campylotropous
(c) anatropous
(d) orthotropous. (2004)
67. Which of the following propagates through leaf-tip?
(a) walking fern
(b) sprout-leaf plant
(c) Marchantia
(d) moss. (2004)
68. Anthesis is a phenomenon which refers to
(a) reception of pollen by stigma
(b) formation of pollen
(c) development of anther
(d) opening of flower bud. (2004)
69. In a flowering plant, archesporium gives rise to
(a) only the wall of the sporangium
(b) both wall and the sporogenous cells
(c) wall and the tapetum
(d) only tapetum and sporogenous cells (2003)
70. In angiosperms pollen tube liberate their male gametes into the
(a) central cell
(b) antipodal cells
(c) egg cell
(d) synergids. (2002)
71. In angiosperm all the four microspores of tetrad are covered by a layer which is formed by
(a) pectocellulose
(b) callose
(c) cellulose
(d) sporopollenin. (2002)
72. What is the direction of micropyle in anatropous ovule?
(a) upward
(b) downward
(c) right
(d) left. (2002)
73. Adventive embryony in Citrus is due to
(a) nucellus
(b) integuments
(c) zygotic embryo
(d) fertilized egg. (2001)
74. In grasses what happens in microspore mother cell for the formation of mature pollen grains?
(a) one meiotic and two mitotic divisions
(b) one meiotic and one mitotic divisions
(c) one meiotic division
(d) one mitotic division. (2001)
75. Anemophily type of pollination is found in
(a) Salvia
(b) bottle brush
(c) Vallisnaria
(d) coconut. (2001)
76. Endosperm is formed during the double fertilization by
(a) two polar nuclei and one male gamete
(b) one polar nuclei and one male gamete
(c) ovum and male gamete
(d) two polar nuclei and two male gametes. (2000)
77. Eight nucleated embryosac is
(a) only monosporic
(b) only bisporic
(c) only tetrasporic
(d) any of these (2000)
78. The endosperm of gymnosperm is
(a) diploid
(b) polyploid
(c) triploid
(d) haploid. (1999)
79. Type of placentation in which ovary is syncarpous unilocular and ovules are on sutures is called
(a) marginal placentation
(b) superficial placentation
(c) apical placentation
(d) parietal placentation. (1999)
80. An interesting modification of flower shape for insect pollination occurs in some orchids in which a male insect mistakes the pattern on the orchid flower for the female species and tries to copulate with it, thereby pollinating the flower. This phenomenon is called
(a) pseudopollination
(b) pseudoparthenocarpy
(c) mimicry
(d) pseudocopulation. (1998)
81. The embiyo in sunflower has
(a) two cotyledons
(b) many cotyledons
(c) no cotyledon
(d) one cotyledon. (1998)
82. The role of double fertilization in angiosperms is to produce
(a) cotyledons
(b) endocarp
(c) endosperm
(d) integuments. (1998)
83. If an angiospermic male plant is diploid and female plant tetraploid, the ploidy level of endosperm will be
(a) tetraploid
(b) pentaploid
(c) haploid
(d) triploid. (1997)
84. The role of double fertilization in angiosperms is to produce
(a) cotyledons
(b) endocarp
(c) endosperm
(d) hormones. (1996)
85. If there are 4 cells in anthers, what will be the number of pollen grains?
(a) 16
(b) 12
(c) 8
(d) 4. (1996)
86. The anthesis is a phenomenon, which refers to
(a) development of anthers
(b) opening of flower bud
(c) stigma receptors
(d) all of these. (1995)
87. In an angiosperm, how many microspore mother cells are required to produce 100 pollen grains?
(a) 75
(b) 100
(c) 25
(d) 50. (1995)
88. The polyembryony commonly occurs in
(a) tomato
(b) potato
(c) Citrus
(d) turmeric. (1995)
89. When pollen of a flower is transferred to the stigma of another flower of the same plant, the pollination is referred to as
(a) autogamy
(b) geitonogamy
(c) xenogamy
(d) allogamy. (1994)
90. Embryo sac represents
(a) megaspore
(b) megagametophyte
(c) megasporophyll
(d) megagamete. (1994)
91. Number of meiotic divisions required to produce 200/400 seeds of pea would be
(a) 200/400
(b) 400/800
(c) 300/600
(d) 250/500. (1993)
92. Double fertilization is characteristic of
(a) angiosperms
(b) anatropous
(c) gymnosperms
(d) bryophytes. (1993)
93. Ovule is straight with funiculus, embryo sac, chalaza and micropyle lying on one straight line. It is
(a) orthotropous
(b) anatropous
(c) campylotropous
(d) amphitropous. (1993)
94. Study of formation, growth and development of new individual from an egg is
(a) apomixis
(b) embryology
(c) embryogeny
(d) cytology. (1993)
95. A population of genetically identical individuals, obtained from asexual reproduction is
(a) callus
(b) clone
(c) deme
(d) aggregate. (1993)
96. Meiosis is best observed in dividing
(a) cells of apical meristem
(b) cells of lateral meristem
(c) microspores and anther wall
(d) microsporocytes. (1992)
97. Double fertilization is fusion of
(a) two eggs
(b) two eggs and polar nuclei with pollen nuclei
(c) one male gamete with egg and other with synergid
(d) one male gamete with egg and other with secondary nucleus. (1991)
98. Syngamy means
(a) fusion of gametes
(b) fusion of cytoplasms
(c) fusion of two similar spores
(d) fusion of two dissimilar spores. (1991)
99. Point out the odd one
(a) nucellus
(b) embryo sac
(c) micropyle
(d) pollen grain (1991)
100. Which of the following pair have haploid structures
(a) nucellus and antipodal cells
(b) antipodal cells and egg cell
(c) antipodal cells and megaspore mother cell
(d) nucellus and primary endosperm nucleus (1991)
101. Embryo sac occurs in
(a) embryo
(b) axis part of embryo
(c) ovule
(d) endosperm. (1991)
102. Pollination occurs in
(a) bryophytes and angiosperms
(b) pteridophytes and angiosperms
(c) angiosperms and gymnosperms
(d) angiosperms and fungi. (1991)
103. Cellular totipotency was demonstrated by
(a) Theodore Schwann
(b) A.V.Leeuwenhoek
(c) F.C.Steward
(d) Robert Hooke. (1991)
104. Entry of pollen tube through micropyle is
(a) chalazogamy
(b) mesogamy
(c) porogamy
(d) pseudogamy (1990)
105. Sperm and egg nuclei fuse due to
(a) base pairing of their DNA and RNA
(b) formation of hydrogen bonds
(c) mutual attraction due to differences in electrical charges
(d) attraction of their protoplasts. (1990)
106. Female gametophyte of angiosperms is represented by
(a) ovule
(b) megaspore mother cell
(c) embryo sac
(d) nucellus. (1990)
107. Male gametophyte of angiosperms/monocots is
(a) microsporangium
(b) nucellus
(c) microspore
(d) stamen. (1990)
108. Which ones produce androgenic haploids in anther cultures
(a) anther wall
(b) tapetal layer of anther wall
(c) connective tissue
(d) young pollen grains. (1990)
109. Which is correct
(a) gametes are invariably haploid
(b) spores are invariably haploid
(c) gametes are generally haploid
(d) both spores and gametes are invariably haploid. (1989)
110. Generative cell was destroyed by laser but a normal pollen tube was still formed because
(a) vegetative cell is not damaged.
(b) contents of killed generative cell stimulate pollen growth
(c) laser beam stimulates growth of pollen tube
(d) the region of emergence of pollen tube is not harmed. (1989)
111. Nucellar embryo is
(a) amphimictic haploid
(b) amphimictic diploid
(c) apomictic haploid
(d) apomictic diploid. (1989)
112. Development of an organism from female gamete/ egg without involving fertilization is
(a) adventitive embryony
(b) polyembryony
(c) parthenocarpy
(d) parthenogenesis. (1989)
113. Perisperm is
(a) remnant of endosperm
(b) persistent nucellus
(c) peripheral part of endosperm
(d) disintegrated secondary nucleus. (1989, 88)
114. Double fertilization and triple fusion were discovered by
(a) Hofmeister
(b) Nawaschin and Guignard
(c) Leeuwenhoek
(d) Strasburger. (1988)
115. Total number of meiotic divisions required for forming 100 zygotes/100 grains of wheat is
(a) 100
(b) 75
(c) 125
(d) 50. (1988)
116. Male gametophyte of angiosperms is shed at
(a) four celled pollen grain
(b) three celled pollen grain
(c) microspore mother cell
(d) anther. (1988)
117. Parthenogenesis is
(a) development of embryo without fertilization
(b) development of fruit without fertilization
(c) development of fruit without hormones
(d) development of embryo from egg without fertilization. (1988)
118. Formation of gametophyte directly from sporophyte without meiosis is
(a) apospory
(b) apogamy
(c) parthenogenesis
(d) amphimixis. (1988)
1. (b) :
Filliform apparatus is a mass of finger like projections of the wall into the cytoplasm. It is present in synergids (help cells) of the embryo sac, in the micropylar region. It guards the pollen tube inside the ovule towards the embryo sac.
2. (a) :
In angiosperms, microsporogenesis i.e., formation of microspores (or pollen grains) occurs by the meiotic divisions of diploid microspore mother cells (or pollen mother cells). Microsporogenesis takes place in the anther. Megasporogenesis i.e. formation of megaspores occurs by the meiotic divisions of diploid megaspore mother cells. Megasporogenesis takes place in the ovule.
3. (d) :
In cucumber, unisexual flowers i.e., separate male and female flowers are present on the same plant (Monoecious plant).
4. (d) :
In Cocos nucifera (coconut), the coconut water represents free-nuclear endosperm and the surrounding kernel represents the cellular endosperm. The primary endosperm nucleus (PEN) first undergoes a number of free nuclear divisions without wall formation to form a large number of free nuclei (free nuclear endosperm). When the fruit is about 50 mm long, the embryo sac gets filled with a clear fluid in which float numerous nuclei of various sizes. At a later stage (about 100 mm long fruit), the suspension shows, in addition to free nuclei, several cells each enclosing a variable number of nuclei. Gradually these cells and free nuclei start settling at the periphery of the cavity, and layers of cellular endosperm start appearing. This forms the coconut meat. The quantity of the cellular endosperm increases further by divisions of the cells.
5. (b) :
Parthenocarpic fruits are the fruits which are formed without fertilisation. These fruits are naturally seedless, e.g., banana.
6. (c) :
The protoplast of the male gametophyte divides mitotically to produce two unequal cells — a small generative cell and a large vegetative cell. The generative cell divides later into two non-motile male gametes (or sperms). Thus, the male gametophyte in angiosperms produces two sperms and a vegetative cell. The vegetative cell, later on, grows to produce pollen tube.
7. (d)
8. (c) :
Geitonogamy involves transfer of the pollen from one flower of a plant to the stigma of another flower of the same plant. As the pollen has to move from one flower to another flower, it requires a pollinating agent. Yet it is genetically similar to autogamy, as both the flowers of the plant, share the same genotype of the plant.
9. (b):
Honey is made from nectar through a process of regurgitation and evaporation. Honey bees transform saccharides (carbohydrates) into honey by regurgitating it a number of times, until it is partially digested. The bees do the regurgitation and digestion as a group. After the last regurgitation, the aqueous solution is still high in water, the process continues by evaporation of much of the water and enzymatic transformation. Honey is produced by bees as a food source.
10. (c) :
Ovule is an integumented megasporangium found in spermatophytes which develops into seed after fertilization. An angiospermic ovule is typically an ovoid and whitish stmcture. It occurs inside ovary where it is attached to a parenchymatous cushion called placenta either singly or in a cluster. The ovule is stalked. The stalk is called funiculus or funicle. The point of attachment of the body of the ovule with the funiculus is known as hilum. It is present as a scar on a mature seed.
11. (d):
Style is traversed by the pollen tube to reach the ovule.lt is of two types – hollow and solid. In hollow styles, the stylar canal is lined by glandular cells, which are usually multinucleate and polyploid whereas solid style has a core of transmitting tissue, composed of thin walled cells, through which, the pollen tube moves.
12. (d) :
Sexual reproduction in algae takes place through fusion of two gametes. In Spirogyra, the gametes are similar in size (isogamy) and non- flagellated (non-motile).
13. (a) :
Geitonogamy is the pollination taking place between the two flowers of the same plant or genetically similar plant. Hence, genetically it is self pollination but since the agency is involved, it is ecologically, cross pollination.
14. (b) :
An aggregate fruit or etaerio is a group of simple fruitlets that develop from free ovaries (apocarpus condition) of a single flower (single gynoecium).
15. (c):
Pollen grains are believed to be rich in nutrients (protein 7-26 % carbohydrates 24-48%, fats 0.9-14.5%). They are taken as tablets or syrups to improve health. They also enhance performance of athletes and race horses.
16. (d) :
In the ovule, the pollen tube is attracted by secretions of synergids. Usually the pollen tube enters the embryo sac by passing into one of the two synergids and is guided by the filiform apparatus of the synergids in their movement. Pollen tube then breaks open and releases its contents in the embryo sac. Antipodals and synergids later degenerate.
17. (d) :
In majority of dicot seeds, including pea, the endosperm is consumed during seed development and the food is stored in cotyledons and other regions. They are called non-endospermic or exalbuminous seeds.
18. (c)
Gemmule and conidia are asexual propagules thus no meiosis takes place in them. Megaspores are haploid which are formed as a result of meiosis of diploid megaspore mother cell. Meiocyte is any cell that undergoes meiosis.
19. (d)
20. (a) :
Both perisperm and endosperm are nutritive layers. Perisperm is residual persistent nucellus of seed prior to fertilization while endosperm develops when one of the sperm cells fuses with two haploid polar nuclei. Thus perisperm is diploid while endosperm is a triploid tissue.
21. (a) :
Cleistogamy is the process of pollination and fertilization before the flower has opened. In such flowers, the anther and stigma lie close to each other. When anthers dehisce in the flower buds, pollen grains come in contact with the stigma to effect pollination. Thus, cleistogamous flowers are invariably autogamous as there is no chance of cross-pollen landing on the stigma. Cleistogamous flowers produce assured seed-set even in the absence of pollinators.
22. (a):
In angiosperms, body of the ovule consists of a mass of parenchymatous cells called nucellus, which is equivalent to megasporangium. A megasporangium alongwith its protective integuments is called as an ovule.
23. (b):
A microsporangium is generally surrounded by four wall layers – the epidermis, endothecium, middle layers and the tapetum. The outer three wall layers perfom the function of protection and help in dehiscence of anther to release the pollen. The innermost wall layer is the tapetum. It nourishes the developing pollen grains. Cells of the tapetum are food rich and possess dense cytoplasm and generally have more than one nucleus. They disintegrate to liberate the contents which is absorbed by the developing spores.
24. (a) :
Sexual reproduction always involves meiosis (zygotic in case of haploid individuals and gametic in case of diploid individuals). Meiosis results in crossing over between chromosomes during prophase I generating new recombinations. Besides, sexual reproduction generally involves combination of genes from two different organisms. Thus, sexual reproduction generates new genetic combinations leading to variations.
25. (c) :
In Vallisneria, water pollination occurs while mulberry and maize undergo wind pollination. In cucumber, animal pollination is observed.
26. (a) :
In some seeds, the endosperm persists in the seed as food storage tissue. Such seeds are called endospermic or albuminous, e.g., castor, maize, wheat, barley, rubber, coconut.
27. (d) :
One hypodermal nucellar cell of the micropylar region of ovule differentiates as the sporogenous cell. It forms a diploid megaspore mother cell or megasporocyte. The megaspore mother cell undergoes meiosis and forms a row of four haploid megaspores. Only the chalazal megaspore remains functional while the other three degenerate.
28. (a) :
In cleistogamy, as the flowers never open so there is no alternative of self pollination. It is invariably autogamous. In xenogamy, pollination takes between two flowers of different plants (genetically and ecologically).
Chasmogamy occurs when the flowers’expose their mature anther and stigma to the pollinating agents.
Geitonogamy is the pollination taking place between the two flowers of the same plant or genetically similar plant. Genetically, it is self pollination but as the agency is involved it is ecologically cross pollination.
29. (c) :
Pollen grain is a haploid, unicellular body. It is cuticularised and the cutin is of special type called sporopollenin, which is resistant to chemical and biological decomposition. It can withstand high temperatures as well as strong acids and alkalis. This is why, pollen wall is preserved for long periods in fossil deposits. In addition pollen wall possesses proteins for enzymatic and compatability reactions.
30. (a) :
Autogamy and geitonogamy are two forms of self pollination. In autogamy, pollen falls on stigma of the same flower. While in geitonogamy pollens from a flower fall on the stigma of some other flower on the same plant. Papaya is a dioecious plants thus both autogamy and geitonogamy are prevented in it.
31. (b) :
Sporopollenin is a major component of the tough outer (exine) walls of spores and pollen grains. It is chemically very stable and is usually well preserved in soils and sediments. It can withstand environmental extremes and cannot be degraded by enzymes and strong chemical reagents.
32. (a) :
Yeast and other ascomycetes characteristi- cally produce ascospores. Chlamydomonas is an alga and conidia are not found in algae. Ginger propagates by rhizome not by sucker. Onion propagates by bulb ‘ which is an underground, modified stem.
33. (a) :
Some plants such as Viola (common pansy), Oxalis, and Commelina produce two types of flowers- chasmogamous flowers which are similar to flowers of other species with exposed anthers and stigma, and cleistogamous flowers which do not open at all. In such flowers, the anthers and stigma lie close to each other. When anthers dehisce in the flower buds, pollen grains come in contact with the stigma to effect pollination. Thus, cleistogamous flowers are invariably autogamous as there is no chance of cross-pollen landing on the stigma. Cleistogamous flowers produce assured seed-set even in the absence of pollinators.
34. (c) :
In a pollen grain, exine is thin or absent at certain places. These areas may have thickened intine or deposition of callose. They are called germ pores (if rounded) or germinal furrows (if elongated). After pollination, the pollen grain on the stigma absorbs water and nutrients from the stigmatic secretion through its germ pores. The tube or vegetative cell enlarges and comes out of pollen grains through germ pore to form a pollen tube.
35. (a) :
In 60% of flowering plants, the pollen grains are shed at two-celled stage (tube cell + generative cell). Further, development of male gametophyte (pollen grain) occurs on stigma. Pollen grain gives rise to pollen tube which absorbs nourishment from the cells of style for its growth. Generative cell divides to give rise to two male gametes. Out of these, one fuses with the egg to form diploid zygote (generative fertilization or syngamy) whereas the second male gamete fuses with the two haploid polar nuclei or diploid secondary nucleus of the central cell to form primary endosperm nucleus (vegetative fertilization or triple fusion). These two acts of fertilization occur in the same embryo sac and are referred to as double fertilization.
36. (d) :
Anemophily is an abiotic means of pollination by wind and, being non-directional, a wasteful process as the pollen would reach the stigma through wind is a hit-or-miss affair. During the transit of pollen through wind, a considerable amount of pollen is lost because it never reaches a proper stigma. To stand this loss, anemophilous plants have to produce enormous quantities of pollen. Anemophily is also associated with reduction in the number of ovules per ovary. Some models predict that plants benefit from numerous inexpensive flowers distributed throughout the inflorescence, each with a single ovule or a few ovules. In grasses there is just one ovule per ovary. This is to increase the probability of successful pollination of each ovule.
37. (c) :
In angiosperms, the female gametophyte is called embryo sac. It contains 8 nuclei but 7 cells — 3 micropylar, 3 chalazal and one central. The three micropylar cells are collectively known as egg apparatus. One middle cell is larger and is called egg or oosphere. The remaining two cells are called synergids or help cells. Each of them (synergids) bears a filiform apparatus in the micropylar region, a lateral hook, chalazal vacuole and a central nucleus.
38. (a) :
In nucellar polyembryony, some of the nucellar cells surrounding the embryo sac start dividing. Then it protrudes into the embryo sac and develop into the embryos. In such species, each ovule contains many embryos. Occurrence of more than one embryo in a seed is referred as polyembryony. Nucellar polyembryony is found in many of the citrus and mango varieties.
39. (d) :
Autogamy is a kind of pollination in which the pollen from the anthers of a flower are transferred to stigma of the same flower. Cleistogamy, homogamy, bud pollination are three methods of the autogamy.Cleistogamy occurs in those plants, which never open and ensure complete self-pollination. E.g., Commelina bengalensis, Oxalis, Viola etc.
40. (d) :
Potato is the common example of stem-tuber. It stores starch as reserve food material. The potato- tubers are used for vegetative propagation. These possess axillary buds over their nodes or eyes. The buds produce new plantlets when a stem-tuber or a part of it having an eye is placed in the soil.
41. (c) :
Anemophily is pollination of a flower in which the pollen is carried by the wind. Examples of anemophilous flowers are those of grasses and conifers.
42. (a) :
Embryo sac is a cell that develops in the ovule of flowering plants. It is equivalent to the female gametophyte of lower plants, although it is very much reduced. Typically it contains eight nuclei formed by division of the megaspore mother cell. Megaspore mother cell divides by meiosis to give rise to four haploid megaspores. One of the megaspores develops into the embryo sac; the others abort.
43. (d) :
Apomixis is a reproductive process in plants that superficially resembles normal sexual reproduction but in which there is no fusion of gametes. The embryos develop simply by division of a diploid cell the ovule. So, the progenies produced are identical to the parent. In vegetative reproduction also progenies produced are identical to the parent.
44. (b) :
Apomixis is abnormal kind of sexual reproduction in which egg or other cells associated with egg (synergids, antipodals, etc.) develop into embryo without fertilization and meiosis. Development of embryos directly from sporophytic tissues like nucellus and integuments is called adventive embryony which is also a type of apoximis. E.g., Citrus, mango.
45. (b) :
Geitonogamy is the transfer of pollen grains from the anther to stigma of another flower on the same plant or genetically similar plant, e.g., in maize.
46. (b) :
Pollination by wind is called anemophily and such plants in which pollination occurs by wind are called anemophilous plants. Anemophilous plants are characteristized by small flowers, pollens present in large number which are small, dry and light in weight (carried upto 1300 Km by wind), number of ovules generally reduced in ovary (biological significance), feathery or brushy stigma (to receive the pollen). Grasses and palms are generally anemophilous.
47. (c) :
A – offset of water hyacinth (Eichhornia)
B – Antheridiophore of Marchantia
C – Antipodals of the mature embryo sac
D – Oogonium of Chara
48. (b) :
In Pistia (water lettuce) vegetative propagation occurs by offset where one intemode long runners grows horizontally along the soil surface and gives rise to new plants either from axillary or terminal buds.
49. (c) :
Vegetative propagation in mint occurs through sucker.
50. (d) :
Megaspore is the initial cell or beginning of female gametophyte or embryo sac. The nucleus of megaspore undergoes divisions and gives rise to embryo sac or female gametophyte, which is called megagametogenesis. During development, the single nucleus of functional megaspore (of chalazal end) undergoes 3 mitotic divisions to form 8 nuclei. Out of these 8 nuclei, 4 are present at micropylar end and 4 at chalazal end. One nucleus from each group comes in centre to form 2 polar nuclei. Remaining 3 nuclei at micropylar end constitute egg apparatus and remaining 3 nuclei at chalazal end constitute 3 antipodal cells or antipodals. So it is 3 + 2 + 3 arrangement.
so fully developed normal type of female gametophyte or embryo sac is 8-nucleated and 7-celled structure.
51. (b) :
Within the embryo sac three cells are grouped together at the micropylar end and constitute the egg apparatus. The egg apparatus, in turn, consists of two synergids and one egg cell. The synergids have special cellular thickenings at the micropylar tip called filiform apparatus, which plays an important role in guiding the pollen tubes into the synergid. Three cells are at the chalazal end and are called the antipodals. The large central cell, has two polar nuclei.
52. (c) :
Unisexuality or dicliny is a condition in which two types of unisexual flowers are present i.e., staminate (male flower) and pistillate (female flower). The plant may be monoecious or dioecious. This is a device for cross pollination (or xenogamy). Both xenogamy and geitonogamy (i.e. transfer of pollen from anther of one flower to stigma of another flower of either the same or genetically similar plant) are included under allogamy/cross pollination. Autogamy or self pollination (i.e. transfer of pollen from anther to stigma of the same flower) occurs in bisexual flower.
53. (a) :
Refer answer 31.
54. (a) :
In the pollen sac (microsporangium) of the anther, haploid microspores are formed by mitosis. Mitosis then follows to produce a two-celled pollen grain with a small generative cell and a large vegetative cell. This generative cell will undergo further mitosis to form two male gametes (nuclei). The pollen tube grows through a spore in the pollen grain, with the tube (vegetative) nucleus at its tips and the male nuclei behind.
55. (d) :
If two plants can reproduce freely with each other and form seeds, they are concluded to belong to same species. Plants belonging to same species have mostly every character common and will be able to reproduce freely with each other to produce new generations.
56. (d) :
Anther consists of microsporangia or pollen sacs. The archesporium gives rise to parietal cells and primary sporogenous tissue. Sporogenous cells divide to form pollen grain or microspore mother cells. They are diploid and connected by plasmodesmata. The microspore, mother cells consists of a callose wall inner to the cell wall. The mother cell then undergoes meiosis and forms tetrads of microspores. Finally the wall of the mother cell degenerates and pollen grains are separated.
57. (c) :
Development of fruits without fertilization is called parthenocarpy and such fruits are called parthenocarpic fruits. Parthenocarpic fruits are seedless. A flower is emasculated and auxins are applied to the stigma of the flower, it forms a parthenocarpic fruit. For parthenocarpy induction by auxins, these should be applied after anthesis (first opening of flower) and by gibberellins, these should be applied earlier i.e., at anthesis.
58. (c) :
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 is known as scutellum.
Tire scutellum does not contain food and its function is to absorb food from the endosperm and transfer it to the growing parts of the embryo. The plumule consists of growing tip of the shoot along with few young leaf primordia. It is covered by a sheath called coleoptile. The radicle which lies at the base of the grain is also covered with a sheath called coleorhiza. The hypocotyl is very short and is represented by a short axis in between radicle and plumule.
59. (c) :
Refer answer 50.
60. (a) :
The arrangement of ovules inside the ovary on placenta is called placentation. Sweet pea or Lathyrus odoratus belongs to family leguminosae or fabaceae and in all the members of this family the placentation is marginal in which ovary is unilocular and ovules are borne on margin.
61. (b) :
Leaves of a number of plants develop or possess adventitious buds for vegetative propagation e.g. Bryophyllum, Kalanchoe, Adiantum caudatum etc.
62. (a) :
Normal type of sexual reproduction having two regular features, i.e., meiosis and fertilization, is called amphimixis. But in some plants, this normal sexual reproduction (amphimixis) is replaced by some abnormal type of sexual reproduction called apomixis.
Apomixis may be defined as, ‘abnormal kind of sexual reproduction in which egg or other cells associated with egg (synergids, antipodals, etc.) develop into embryo without fertilization and with or without meiosis’.
Adventive embryony is a type of apomixis in which development of embryos directly from sporophytic tissues like nucellus and integuments takes place, e.g., in Citrus, mango, etc.
63. (a) :
Depending upon position of micropyle in
relation to chalaza, ovules are of 6 types in angiosperms. In amphitropous type the curvature is observed both in body of ovule and embryo sac. The embryo sac assumes horse shoe-shape. Micropyle is directed downwards. It is commonly found in families papaveracerae, alismaceae and butomaceae.
Circinotropous ovule is characteristic of family cactaceae. Here the ovule is straight first but due to more growth on one side gets inverted and later becomes straight again.
Orthotropous ovule is the most primitive and of simplest type. It is also known as atropous or straight ovule.
Anatropous ovule is the most common type of ovule found in angiosperms. Here the body of the ovule gets inverted and micropyle is on lower side.
64. (c) :
The pollen tube enters into the embryo sac at the micropylar end. This entry may be between egg and one synergid or between wall of embryo sac and synergid or through one synergid. So one synergid is always degenerated to allow the entry of the pollen tube.
65. (a) :
Endosperm is formed due to fusion of the haploid male gamete with the polar nucleus of the embryo sac. But in this case the male plant is tetraploid so that its gametes would be diploid. When these diploid gametes fuse with two polar nuclei of the embryo sac the resultant endosperm would be tetraploid.
66. (a) :
In hemianatropous or hemitropous ovule, the nucellus and integuments are at right angles to stalk or funiculus so that the ovule becomes curved. It is commonly found is primulaceae and Ranunculus. In campylotropous ovule the body of the ovule gets curved and micropyle is directed downwards. Atropous ovule is erect and micropyle, chalaza and funiculus are in the same straight line. Anatropous ovule is the most common type of ovule in angiosperms. In this the body of the ovule gets inverted and the micropyle is on lower side.
67. (a) :
In Adiantum caudatum, adventitious buds develop at the leaf tips. When such leaf tips happen to touch the soil, they form new plant. This process helps in propagation of this fern to a large area. Adiantum caudatum is commonly called as walking fern.
68. (d) :
Anthesis is the process of opening floral buds. Reception of pollen by stigma is called pollination. Formation of pollen is called microsporogenesis.
69. (b) :
In flowering plants, archaesporial cells are vertical rows of hypodermal cells at four angles of anther. These undergo periclinal (transverse) division to form an outer primary parietal cell and inner sporogenous cell. Primary parietal wall after few more periclinal divisions forms anther wall and sporogenous cells give rise to sporogenous tissue.
70. (d) :
On reaching of pollen tube inside the embryo sac, the 2 male gametes are discharged through a sub¬terminal pore in pollen tube. The contents of pollen tube are discharged in the synergid and the pollen tube does not grow beyond it in the embryo sac. Further the cytoplasm of pollen tube is restricted to chalazal end of this synergid cell.
71. (a) :
Each microspore or pollen is having a two layered wall. Outer layer is thick tough cuticularized called exine, which is chiefly composed of a material called ‘sporopollenin’. Inner layer is thin, delicate and smooth called intine, which is made of pectocellulose. Exine is not uniform but is thin at one or more places in the form of germ pores. Whereas intine made of pectocellulose covers the entire surface of pollen grains.
72. (b) :
Anatropus ovule is the most common type of ovule found in angiosperms. Here the body of the ovule gets inverted and micropyle is on lower side. It comes very close to the hilum and the chalaza is upwardly directed.
73. (a) :
Presence of more than one embryo inside the seed is called polyembryony. It is more common in gymnosperms than angiosperms. In angiosperms, it is generally present as an unusual feature in few cases like Citrus, mango etc.
In Citrus many embryos are formed from the structures outside the embryo (like nucellus). This is commonly called adventive polyembryony. In Citrus upto 10 nucellar embryos are formed.
74. (b) :
Grass is a monocot plant. Primary sporogenous cell gives rise to microspore mother cells or pollen mother cells. Each MMC on reduction division gives rise to 4 microspores or pollens and
this formation of microspores or pollens is called microsporogenesis. Karyokinesis is of successive type. The successive type of cytokinesis is common in monocots. Here both meiotic I and II nuclear divisions are followed by wall formation and it leads to isobilateral tetrad.
75. (d) :
Anemophily is the pollination by wind. Anemophilous plants are characterized by small flowers, pollens present in large number which are small, dry and light in weight, number of ovules generally reduced in ovary, feathery or brushy stigma to recieve the pollen. All these features are shown by coconut flower.
In Vallisneria pollination occurs outside water called epihydrophily. Callistemon (Bottle brush) is pollinated by birds and is an example of omithophily. Salvia is insect pollinated and is an example of entomophily.
76. (a) :
Double fertilization is the simultaneous occurrence of syngamy and triple fusion. Syngamy involves fusion of one male gamete with egg cell to form zygote. The result of syngamy is zygote (2n) which ultimately develops into embryo.
The second male gamete fuses with 2 polar nuclei or secondary nucleus to form triploid primary endosperm nucleus and this is called triple fusion. This primary endosperm nucleus (3n) ultimately develops into a nutritive tissue for developing embryo called endosperm.
77. (d) :
On the basis of number of megaspore nuclei taking part in development of female gametophyte or embryo sac, there are 3 types of embryo sacs-
(i) Monosporic type – In this type the single nucleus of functional megaspore undergoes 3 mitotic divisions to form 8 nuclei, 7 cells.
(ii) Bisporic type – Here embryo sac develops from 2 megaspore nuclei out of 4 nuclei formed after reduction division of MMC. It is also 8 nucleated.
(iii) Tetrasporic type – Here all the 4 megaspore nuclei formed after reduction division of megaspore mother
cell are functional and take part in development of embryo sac. It is further of different types. Fritillaria type, Plumbago type and Adoxa type are 8 nucleated.
78. (d) :
The endosperm of gymnosperms is haploid. It is a pre-fertilization tissue and is equivalent to female gametophyte, hence it is haploid in nature but in angiosperms it is post-fertilization tissue and is generally triploid in nature.
79. (a) :
Arrangement of ovules inside the ovary on placenta is called placentation. In marginal placentation ovary is unilocular and the placenta develops along the junction of the two margins of the carpel, called the ventral suture. It occurs in pea, wild pea, gram etc. In superficial placentation ovary is multilocular and ovules are borne on inner surface or partition walls as in water lily. In parietal placentation the ovary is unilocular and the ovules are borne on periphery as in Brassica, Argemone etc.
80. (d) :
In an orchid Ophrys speculum, there is most interesting and unique mechanism of pollination. Here pollination occurs by a wasp called Culpa aurea. In this orchid, pollination occurs by act of pseudocopulation. The appearance and odour of Ophrys is similar to female wasp and are mistake by male wasps and they land on Ophrys flowers to perform act of pseudo-copulation and thus pollination takes place. This plant-insect relationship is useful only to plant.
81. (a) :
Sunflower (Helianthus) belongs to family asteraceae of dicotyledons. A dicot embryo has an embryonal axis and 2 cotyledons attached to it laterally. So the number of cotyledons in sunflower will be two.
82. (c) :
Refer answer 76.
83. (b) :
If the female plant is tetraploid, then the central cell of embryo sac, which is a fused polar nuclei, will also be tetraploid. Fusion of the tetraploid central cell to the haploid male gamete forms a pentaploid endosperm in the given example.
84. (c) :
Refer answer 76.
85. (a) :
Pollen grains or microspores are formed inside anther, which is the fertile portion of stamen or microsporophyll. Inside the anther, primary sporogenous cell gives rise to microspore mother cells or pollen mother cells (MMC or PMC). Each MMC on reduction division gives rise to 4 microspores or pollens. So these four cells will give rise to 4 x 4 = 16 pollen grains.
86. (b) :
Anthesis refers to opening of a flower bud. It is the duration of life of a flower from the opening of the bud to setting of the fruit.
87. (c) :
Pollen grains or microspores are formed inside anther, which is the fertile portion of stamen or microsporophyll. The formation of microspores or pollens is called microsporogenesis. The primary sporogenous cell gives rise to microspore mother cells or pollen mother cells. Each microspore mother cell on reduction division gives rise to 4 microspores or pollens. So for the formation of 100 pollen grains, 25 MMC are required. It inolves karyokinesis followed by cytokinesis.
88. (c) :
Refer answer 73.
89. (b) :
Refer answer 45.
90. (b) :
Refer answer 50.
91. (d) :
Number of meiotic divisions required to produce 200/400 seeds of pea would be 250/500. 200 seeds of pea would be produced from 200 pollen grains and 200 eggs. 200 pollen grains will be formed by 50 microspore mother cell while 200 eggs will be formed by 200 megaspore mother cell so 250/500.
92. (a) :
Double fertilization is the characteristic feature of angiosperms. This phenomenon first observed by Nawaschih, 1898 in Lilium and Fritillaria. In angiosperms one male gamete fuses with the two polar nuclei to form triploid primary endosperm nucleus. The process is called triple fusion. These two acts together are known as double fertilization.
93. (a) :
Orthotropous ovule is straight with funiculus, embryo sac, chalaza and micropyle lying on one straight line. It is an Polygonum type ovule in which body of the ovule is straight. Funiculus, chalaza, embryo sac and micropyle lie in the same vertical axis.
94. (b) :
Study of formation, growth and development of new individual from an egg is embryology. Study of an individuals life cycle after the fertilization takes place till it develops into a new organism.
95. (b) :
A population of genetically identical individuals, obtained from asexual reproduction is clone. Cloning is a technique by which genetically same individuals can be produced without including any sexual reproduction, e.g. Dolly, the cloned sheep.
96. (d) :
Meiosis is best observed in dividing microsporocytes. Microsporocytes or microspore mother cell after meiosis give rise to microspore. Other cells do not divide by meiosis.
97. (d) :
Refer answer 76.
98. (a) :
Syngamy means fusion of gametes. Syngamy is the phenomenon in which male gamete fuses with the egg.
99. (d) :
Pollen grain is odd one among all the other three. Pollen grain in a male gametophytic structure. Whereas all the other three are found inside ovule (nucellus, micropyle and embryo sac).
100. (b):
Antipodal cells and egg cell are haploid structures as they are after meiosis while the others nucellus, megaspore mother cell and primary endosperm nucleus are diploid structures.
101. (c):
Embryo sac occurs in ovule. Ovule is integumented megasporangium. It consists of nucleus covered by one or two integuments, mounted on a funicle, chalaza and micropyle. The ovule is vascularised.
102. (c):
The term pollination refers to the transfer of pollen from anther to stigma. Because pollens are found only in angiosperms and gymnosperms so this phenomenon relates to angiosperms and gymnosperms only.
103. (c):
Cellular totipotency was demonstrated by F.C. Steward. Cellular totipotency is the technique of regeneration or development of complete plant from explant or cell or tissue of the plant.
104. (c):
In most of the plants the pollen tube enters the ovule through the micropyle and the phenomenon is called as porogamy. Entry through chalaza is chalazogamy and through integuments or funiculus is mesogamy.
105. (d):
The two gametes i.e., sperm released by pollen tube and egg move in opposite direction by an unknown mechanism but most probably by streaming currents of cytoplasm i.e., due to attraction of their protoplasts. The nucleus of one male gamete fuses with the egg nucleus and the phenomenoft is called fertilization.
106. (c):
Female gametophyte of angiosperms is represented by embryo sac. The polygonum type of embryo sac is eight nucleate and seven celled. It is found in more than 80% plant families. The nucleus of megaspore undergoes division and give rise to embryosac or female gametophyte by the process of megagametogenesis.
107. (c):
Male gametophyte of angiosperms is microspore. Microspore is haploid, uninucleate, minute spores produced in large numbers as a result of meiosis in microspore mother cell inside the microsporangia. These are the first cell of gametophytic generations in angiosperms.
108. (d):
Young pollen grains produce androgenic haploids in anther cultures. Because rest all i.e., anther wall, tapetal layer of anther wall and connective tissue are the diploid tissue as they are part of anther pollen grains are produced by meiosis.
109. (a):
Gametes are invariably haploid. Spores are formed in lower plants by mitotic division and they may be diploid but gametes are always be made by meiosis and they are always haploid.
110. (a):
Generative cell was destroyed by laser but a normal pollen tube was still formed because vegetative cell is not damaged. Each microspore divide by mitotic division making a smaller generative cell and a larger vegetative cell or tube cell. If generative cell is damaged then the normal pollen tube will be formed because pollen tube is formed by vegetative cell not by generative cell of microspore.
111. (d) :
Nucellar embryo is apomictic diploid. Substitution of usual sexual reproduction by a form of reproduction which does not include meiosis and syngamy is called apomixis. In this technique embryo is developed by some other tissue without fertilization e.g., nucellus or integuments or infertilized egg. Nucellus in a diploid tissue so nucellar embryo is apomictic diploid.
112. (d) :
Development of an organism from female gamete/egg without involving fertilization is parthenogenesis and when a fruit is developed by this technique it is called parthenocarpy.
113. (b):
Perisperm is persistent nucellus. Endosperm formation is accompanied by degeneration of nucellus.
114. (b) :
Double fertilization and triple fusion were discovered by Nawaschin and Guignard in Fritillaria and Lilium. In angiosperms one male gamete fuses with the two polar nuclei to form triploid primary endosperm nucleus. The process is called triple fusion. These two acts together are known as double fertilization.
115. (c) :
For formation of 100 zygotes, 100 male gametes and 100 female gametes (eggs) are required. 100 male gametes are developed from 100 microspores (from 25 meiotic divisions) and 100 eggs are developed from 100 megaspores (from 100 meiotic division).
Hence, number of meiotic divisions necessary for 100 zygotes formation = 25 + 100 = 125.
116. (b) :
The male gametophyte or microspore is shed at 3-nucleate stage. The microspore undergoes only two mitotic divisions.
117. (d) :
Parthenogenesis is the phenomenon of development of embryo from egg without fertilization. It is of two types haploid and diploid parthenogenesis. It usually occurs due to defective meiosis that results in egg nucleus having unreduced number of chromosomes.
118. (a) :
Formation of gametophyte directly from sporophyte without meiosis and spore formation is apospory. The gametophyte thus has diploid number of chromosomes. Such gametophyte may form viable gametes which fuse to form tetraploid sporophyte. Apogamy is development of sporophyte directly from gametophytic tissue without fusion of gametes. Amphimixis is normal sexual reproduction. Parthenogenesis is development of embryo from egg without fertilization.
1. Arrange the following events of meiosis in correct sequence (AIPMT 2015)
(i) Crossing over
(ii) Synapsis
(iii) Terminalisation of chiasmata
(iv) Disappearance of nucleolus
(a) (i), (ii), (iii), (iv)
(b) (ii), (iii), (iv), (i)
(c) (ii), (i), (iv), (iii)
(d) (ii), (i), (iii), (iv)
2. 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, Cancelled)
(a) twice the number of chromosomes and four times the amount of DNA
(b) four times the number of chromosomes and twice the amount of DNA
(c) twice the number of chromosomes and twice the amount of DNA
(d) same number of chromosomes but twice the amount of DNA.
3. Select the correct option. (AIPMT 2015, Cancelled)
(a) A-(i), B-(ii), C-(v), D-(iv)
(b) A-(ii), B-(iii), C-(iv), D-(v)
(c) A-(ii), B-(i), C-(iii),D-(iv)
(d) A-(ii), B-(iii), C-(v), D-(iv)
4. 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)
(a) G0 and G1
(b) G1 and S
(c) Only G2
(d) G2 and M
5. In ‘S’ phase of the cell cycle (AIPMT 2014)
(a) amount of DNA doubles in each cell
(b) amount of DNA remains same in each cell
(c) chromosome number is increased
(d) amount of DNA is reduced to half in each cell.
6. The enzyme recombinase is required at which stage of meiosis? (AIPMT 2014)
(a) Pachytene
(b) Zygotene
(c) Diplotene
(d) Diakinesis
7. The complex formed by a pair of synapsed homologous chromosomes is called (NEET 2013)
(a) bivalent
(b) axoneme
(c) equatorial plate
(d) kinetochore.
8. A stage in cell division is shown in the figure. Select the answer which gives correct identification of the stage with its characteristics. (NEET2013)
(a) Cytokinesis: Cell plate formed, mitochondria distributed between two daughter cells.
(b) Telophase: Endoplasmic reticulum and nucleolus not reformed yet.
(c) Telophase: Nuclear envelope reforms,Golgi complex reforms.
(d) Late anaphase: Chromosomes move away from equatorial plate, Golgi complex not present.
9. During meiosis I, the chromosomes start pairing at (Karnataka NEET 2013)
(a) zygotene
(b) pachytene
(c) diplotene
(d) leptotene.
10. During the metaphase stage of mitosis, spindle fibres attach to chromosomes at (Karnataka NEET 2013)
(a) kinetochore
(b) both centromere and kinetochore
(c) centromere, kinetochore and areas adjoining centromere
(d) centromere
11. A stage of mitosis is shown in the diagram. Which stage is it and what are its characteristics? (Karnataka NEET 2013)
(a) Metaphase: Spindle fibers attached to kinetochores, centromeres split and chromatids separate.
(b) Metaphase: Chromosomes moved to spindle equator, chromosomes made up of two sister chromatids.
(c) Anaphase: Centromeres split and chromatids separate and start moving away.
(d) Late prophase: Chromosomes move to spindle equator.
12. During gamete formation, the enzyme recombinase participates during (Prelims 2012)
(a) metaphase-I
(b) anaphase-II
(c) prophase-I
(d) prophase-II
13. The given figure is the representation of a certain event at a particular stage of a type of cell division. Which is this stage? (Prelims 2012)
(a) Prophase-I during meiosis
(b) Prophase-II during meiosis
(c) Prophase of mitosis
(d) Both prophase and metaphase of mitosis.
14. Identify the meiotic stage in which the homologous chromosomes separate while the sister chromatids remain associated at their centromeres. (Mains 2012)
(a) Metaphase I
(b) Metaphase II
(c) Anaphase I
(d) Anaphase II.
15. Select the correct option with respect to mitosis. (Prelims 2011)
(a) chromatids separate but remain in the centre of the cell in anaphase
(b) chromatids start moving towards opposite poles in telophase
(c) Golgi complex and endoplasmic reticulum are still visible at the end of prophase.
(d) chromosomes move to the spindle equator and get aligned along equatorial plate in metaphase.
16. At metaphase, chromosomes are attached to the spindle fibres by their (Mains 2011)
(a) satellites
(b) secondary constrictions
(c) kinetochores
(d) centromeres
17. During mitosis, ER and nucleolus begin to disappear at (Prelims 2010)
(a) late prophase
(b) early metaphase
(c) late metaphase
(d) early prophase.
18. Which stages of cell division do the following figures A and B represent respectively? (Prelims 2010)
(a) metaphase – telophase
(b) telophase – metaphase
(c) late anaphase – prophase
(d) prophase – anaphase.
19. Synapsis occurs between (Prelims 2009)
(a) mRNA and ribosomes
(b) spindle fibres and centromere
(c) two homologous chromosomes
(d) a male and a female gamete
20. 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 (Prelims 2009)
(a) C – karyokinesis
(b) D – synthetic phase
(c) A – cytokinesis
(d) B – metaphase
21. At what stage of the cell cycle are histone proteins synthesized in a eukaryotic cell? (2005)
(a) during G-2 stage of prophase
(b) during S-phase
(c) during entire prophase
(d) during telophase.
22. In the somatic cell cycle
(a) in G1 phase DNA content is double the amount of DNA present in the original cell (2004)
(b) DNA replication takes place in S-phase
(c) a short interphase is followed by a long mitotic phase
(d) G2 phase follows mitotic phase.
23. 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? (2004)
(a) metaphase
(b) telophase
(c) anaphase
(d) prophase.
24. Which one of the following precedes re-formation of the nuclear envelope during M phase of the cell cycle? (2004)
(a) decondensation from chromosomes, and reassembly of the nuclear lamina
(b) transcription from chromosomes, and reassembly of the nuclear lamina
(c) formation of the contractile ring, and formation of the phragmoplast
(d) formation of the contractile ring, and transcription from chromosomes.
25. Mitotic spindle is mainly composed of which protein? (2002)
(a) actin
(b) myosin
(c) actomyosin
(d) myoglobin.
26. Best material for the study of mitosis in laboratory is (2002)
(a) anther
(b) root tip
(c) leaf tip
(d) ovary.
27. Spindle fibre unite with which structure of chromosomes? (2000)
(a) chromocentre
(b) chromomere
(c) kinetochore
(d) centriole.
28. In which stage of cell cycle, DNA replication occurs (2000)
(a) Grphase
(b) S-phase
(c) G2-phase
(d) M-phase.
29. Microtubule is involved in the (1998)
(a) muscle contraction
(b) membrane architecture
(c) cell division
(d) DNA recognition.
30. How many mitotic divisions are needed for a single cell to make 128 cells? (1997)
(a) 28
(b) 32
(c) 7
(d) 14.
31. During cell division in apical meristem, the nuclear membrane appears in (1997)
(a) telophase
(b) cytokinesis
(c) metaphase
(d) anaphase.
32. When paternal and maternal chromosomes change their materials with each other in cell division this event is called (1996)
(a) bivalent-forming
(b) dyad-forming
(c) synapsis
(d) crossing-over.
33. Which typical stage is known for DNA replication? (1996)
(a) S-phase
(b) G2-phase
(c) metaphase
(d) G1-phase.
34. In a somatic cell cycle, DNA synthesis takes place in (1994)
(a) G1 phase
(b) prophase of mitosis
(c) S-phase
(d) G2phase.
35. Which of the following represents the best stage to view the shape, size and number of chromosomes? (1994)
(a) prophase
(b) metaphase
(c) interphase
(d) telophase.
36. Which statement best explains the evolutionary advantage of meiosis? (1994)
(a) meiosis is necessary for sexual reproduction
(b) genetic recombinations are possible from generation to generation
(c) meiosis alternates with mitosis from generation to generation
(d) the same genetic system is passed on from generation to generation.
37. Meiosis II performs (1993)
(a) separation of sex chromosomes
(b) synthesis of DNA and centromere
(c) separation of homologous chromosomes
(d) separation of chromatids.
38. Number of chromatids at metaphase is (1992)
(a) two each in mitosis and meiosis
(b) two in mitosis and one in meiosis
(c) two in mitosis and four in meiosis
(d) one in mitosis and two in meiosis.
39. Mitotic anaphase differs from metaphase in possessing (1991)
(a) same number of chromosomes and same number of chromatids
(b) half number of chromosomes and half number of chromatids
(c) half number of chromosomes and same number of chromatids
(d) same number of chromosomes and half number of chromatids.
40. In meiosis, the daughter cells differ from parent cell as well as amongst themselves due to (1991)
(a) segregation, independent assortment and crossing over
(b) segregation and crossing over
(c) independent assortment and crossing over
(d) segregation and independent assortment.
41. Segregation of Mendelian factor (Aa) occurs during (1990)
(a) diplotene
(b) anaphase I
(c) zygotene/pachytene
(d) anaphase II.
42. Meiosis I is reductional division. Meiosis II is equational division due to (1988)
(a) pairing of homologous chromosomes
(b) crossing over
(c) separation of chromatids
(d) disjunction of homologous chromosomes.
1. (d)
Prophase-I of meiosis has been divided into five sub-stages which occur in the sequence as Leptotene → Zygotene → Pachytene → Diplotene→ Diakinesis. Synapsis i.e., pairing of homologous chromosomes occurs during zygotene. Crossing over i.e., exchange of chromatid segments occurs during pachytene. Terminalisation of chiasmata i.e., shifting of chiasmata towards the ends of chromosomes and complete disappearance of nucleolus take place during diakinesis.
2. (a)
In diploid cells (somatic cells) during Gt phase, DNA content is 2C and chromosome number is 2n whereas in haploid cells (gamete) during G, phase, DNA content is 1C and chromosome number is n. S phase is marked by replication of DNA and the amount of DNA per cell is doubled i.e., it becomes 4C in somatic cells, whereas chromosome number remains same i.e., 2n. Thus, a somatic cell which has just completed S phase, will have 4C DNA content but 2n chromosome number, while the gamete cell has 1C DNA content and n chromosome number.
3. (d)
Synapsis aligns homologous chromosomes – Zygotene
Synthesis of RNA and protein – G2 phase
Action of enzyme recombinase – Pachytene
Centromeres do not separate but chromatids move towards opposite poles – Anaphase I
4. (c)
A cell cycle is divided into G1 S, G2 and M phases. G1 or first growth phase is followed by S phase or synthesis phase. DNA replication occurs in S phase and DNA amount doubles up i.e., a cell with 2C DNA in G21phase will now have 4C DNA. G2phase is second growth phase where DNA content remains 4C. M phase is the phase of division where DNA content either regains 2C level (mitosis) or becomes halved i.e. 1C (in meiosis). G0 phase is the phase of differentiation where cell contains DNA as in the same amount as its parent cell and does not divide further.
5. (a)
In ‘S’ phase of cell cycle the DNA content doubles, i.e., 1C to 2C for haploid cells and 2C to 4C for diploid cells. However, the number of chromosomes does not increase.
6. (a)
Pachytene is characterized by the appearance of recombination nodules, the sites at which crossing over occurs between non-sister chromatids of the homologous chromosomes. Nodules contain multienzyme complex called recombinase. Recombinase is made of endonuclease, exonuclease, unwindase, R-protein, etc.
7. (a)
During zygotene stage chromosomes start pairing together and this process of association is called synapsis. Such paired chromosomes are called homologous chromosomes. Electron micrographs of this stage indicate that chromosome synapsis is accompanied by the formation of complex structure called synaptonemal complex. The complex formed by a pair of synapsed homologous chromosomes is called a bivalent or a tetrad.
8. (c)
The figure given in the question shows a stage of mitotic cell division called as telophase stage. The individuals chromosomes are no longer seen and chromatin material tends to collect in a mass at the two poles. This is the stage which shows the following key events
9. (a)
During zygotene or zygonema of meiotic prophase I the chromosomes become shorter and thicker. The homologous chromosomes come to lie side-by-side in pairs. This pairing of homologous chromosomes is known as synapsis, or syndesis. A pair of homologous chromosomes lying together is called a bivalent.
10. (a)
In metaphase, chromosomes consisting of two sister chromatids get arranged at equator. Discontinuous fibres radiate out from two spindle poles and get connected to the disc shaped structure at the surface of the centromere called kinetochores. These are known as chromosome fibres or tractile fibrils. A kinetochore is a complex protein structure that is analogous to a ring for the microtubule hook; it is the point where microtubules attach themselves to the chromosome.
11. (b)
In metaphase, chromosomes consisting of two sister chromatids get arranged at equator. Discontinuous fibres radiate out from two spindle poles and get connected to the disc shaped structure at the surface of the centromere called kinetochores. These are known as chromosome fibres or tractile fibrils. A kinetochore is a complex protein structure that is analogous to a ring for the microtubule hook; it is the point where microtubules attach themselves to the chromosome.
12. (c)
During gamete formation, the enzyme recombinase participates during pachytene stage of prophase – I. This stage is characterized by the appearance of recombination nodules, the sites at which crossing over occurs between non-sister chromatids of the homologous chromosomes. Crossing over is the exchange of genetic material between two homologous chromosomes. Crossing over is also an enzyme-mediated process and the enzyme involved is called recombinase.
13. (a)
The given figure shows crossing over i.e., exchange of segments between two homologous chromosomes. Crossing over is characteristic of meiosis and occurs during pachytene stage of prophase -1.
14. (c)
During anaphase I, from each tetrad two chromatids of a chromosome move as a unit (dyad) to one pole of a spindle, and the remaining two chromatids of its homologue migrate to the opposite pole. Thus, the homologous chromosomes of each pair, rather than the chromatids of a chromosome, are separated. As a result, half of the chromosomes, which appear in early prophase, go to each pole. Thus the paternal and maternal chromosomes of each homologous pair segregate during anaphase I independently of the other chromosomes.
15. (d)
The plane of alignment of the chromosomes at metaphase is referred to as the metaphase plate. The key features of metaphase are, (1) Spindle fibres attach to kinetochores of chromosomes (2) Chromosomes are moved to spindle equator and get aligned along metaphase plate through spindle fibres to both poles.
16. (c)
The key feature of metaphase is the attachment of spindle fibres to kinetochores of chromosomes. Kinetochores are disc-shaped structures at the surface of the centromeres. These structures serve as the sites of attachment of spindle fibres to the chromosomes that are moved into position.
17. (d)
During early prophase of mitosis, nucleus and cell become spheroid. Viscocity and refractivity of cytoplasm increases. DNA molecules condense to form shortened chromosome. Endoplasmic reticulum and nucleolus starts disappearing.
18. (c)
19. (c)
During zygotene or zygonema of meiotic prophase I the chromosomes become shorter and thicker. The homologous chromosomes come to lie side-by-side in pairs. This pairing of homologous chromosomes is known as synapsis, or syndesis. A pair of homologous chromosomes lying together is called a bivalent.
20. (b)
In cell cycle there are two main phases- interphase and mitotic phase. Interphase is divided into 3 stage G1, S and G2, G1 is first growth phase. S is synthetic phase and G2 is second growth phase.
21. (b)
During S phase or synthetic phase the replication of DNA takes place. For replication of DNA histone proteins are required so they are also synthesized during this phase. It takes about 30%- 50% of the total cell cycle. Prophase and telophase are stages involved in mitosis or meiosis. During G2 phase division of centrioles, mitochondria and chloroplasts occurs.
22. (b)
Interphase is the stage between two successive cell divisions. During interphase, chromosomes are decondensed and are distributed throughout the nucleus. It is the largest period in the cell cycle and is divided into three phase – G1, S and G2. During G1 phase the cell grows and synthesis mRNA, mRNA, ribosomes, enzymes and proteins necessary for DNA synthesis occurs. During S phase replication of DNA takes place. The nucleotides get assembled and DNA molecules are synthesized. During G2phase organelles like centrioles are doubled and mitochondria, chloroplasts etc. divide.
23. (a)
Metaphase is the best time to count and study the number and morphology of chromosomes. The distinctly visible chromosome arrange themselves at the equatorial or metaphasic plate. The centromeres lie at the equational plate while the limbs are placed variously according to their size and spiral arrangement. At prophase the chromosomes appear thin and filamentous, forming a network. So they are not very clearly visible. At telophase the chromosomes uncoil and lengthen and therefore are not clearly seen. Anaphase also shows chromosomes distinctly and they can be counted. But during anaphase chromatids seperate and start moving towards opposite pole. So for counting metaphase is the best stage.
24. (c)
M-phase or mitotic phase is the actual division phase and formation of contractile ring and formation of phragmoplast precedes reformation of nuclear envelope. Contractile ring is belt-like bundle of actin and myosin that appears during cell division immediately below the plasma membrane. Contraction of this ring leads to the separation of the two daughter cells. Phragmoplast is the region of plant cell cytoplasm that becomes evident in the latter stages of mitosis. It forms from the residual microtubules of the polar mitotic spindle and appears to function in transporting materials to the new cell plate forming between the daughter cells. Once the cell plate is complete, the phragmoplast is divided and gradually disappears, the cell plate finally becoming transformed into the middle lamella lying between the new cell walls.
25. (c)
A spindle of fine fibres begins to develop during prophase. It consists of microtubules which are made of protein called tubulin and certain other associated proteins. These delicate fibres radiate from the centriole and constitute aster. This option was not given in the entrance paper. As actin and myosin are involved as contractile machinery in many nonmuscle cells so it can be considered as the correct answer. Myoglobin is present in muscles which can bind to oxygen.
26. (b)
Mitosis occurs both in somatic cells as well as in germ cells of the gonads. In plants mitosis occurs in the meristematic cells of root tip or shoot tip. These cells divide at a faster rate. So the root tip shows active cell division and are used in the laboratory to study mitosis. For studying meiosis young anthers are used.
27. (c)
Spindle is microtubular apparatus that appears in many eukaryotic cells at the beginning of nuclear division and is responsible for the ordered separation of the chromosomes, chromosomes being attached to the spindle fibres by their centromeres. Two types of spindle fibres can be distinguished as the interpolar fibre, which stretches continuously from pole to pole of the spindle; the kinetochore fibre, which stretches from the pole to the centromere (kinetochore) of an individual chromosome. The mechanism by which the chromosomes move and the spindle fibres contract remains unclear. Cells of animals and lower plants possess centrioles, which act as organizer regions for spindle microtubule formation, but centrioles are absent from the cells of higher plants.
28. (b)
Interphase is the stage between two successive cell divisions. During interphase, chromosomes are decondensed and are distributed throughout the nucleus. It is the largest period in the cell cycle and is divided into three phase – G1, S and G2. During G1 phase the cell grows and synthesis mRNA, mRNA, ribosomes, enzymes and proteins necessary for DNA synthesis occurs. During S phase replication of DNA takes place. The nucleotides get assembled and DNA molecules are synthesized. During G2 phase organelles like centrioles are doubled and mitochondria, chloroplasts etc. divide.
29. (c)
Microtubules are unbranched hollow submicroscopic tubules of protein tubulin which develop on specific nucleating regions and can undergo quick growth or dissolution at their ends by assembly or disassembly of monomers. Microtubules form spindle during cell division. Centrioles help in cell division by forming spindle poles or microtubules. In animal cells, microfilament collect in the middle region of the cell below the cell membrane. They induce the cell membrane to invaginate. In plant cells, cell plate is formed to separate the two daughter cells. Some of the spindle fibres called interzonal microtubules are deposited around phragmoplast. Vesicles from Golgi apparatus are deposited and coalesce on the phragmoplast to form a cell plate.
30. (c)
Mitosis is an equational division where after division each cell produces two daughter cells, therefore after 7 divisions one cell will give 128 cells in case of mitosis.
31. (a)
In apical meristems mitotic divisions occur at a rapid rate. In late telophase of mitosis, a nuclear membrane appears on the outside from either pieces of nuclear envelope or endoplasmic reticulum. The telophase may last as long as the prophase.
32. (d)
Crossing-over is responsible for inducing variability. It involves an exchange of equal segments of non-sister chromatids belonging to two different but homologous chromosomes. Crossing over takes place at four stranded stage. Only two ofthe four chromatids take part in crossing over. The other two are called non crossovers. Zygotene is characterized by pairing of homologous chromosomes which is called synapsis. The first meiotic division which is completed at first telophase may be followed by cytokinesis giving rise to a dyad.
33. (a)
Interphase is the stage between two successive cell divisions. During interphase, chromosomes are decondensed and are distributed throughout the nucleus. It is the largest period in the cell cycle and is divided into three phase – G1, S and G2. During G1 phase the cell grows and synthesis mRNA, mRNA, ribosomes, enzymes and proteins necessary for DNA synthesis occurs. During S phase replication of DNA takes place. The nucleotides get assembled and DNA molecules are synthesized. During G2phase organelles like centrioles are doubled and mitochondria, chloroplasts etc. divide.
34. (c)
Interphase is the stage between two successive cell divisions. During interphase, chromosomes are decondensed and are distributed throughout the nucleus. It is the largest period in the cell cycle and is divided into three phase – G1, S and G2. During G1 phase the cell grows and synthesis mRNA, mRNA, ribosomes, enzymes and proteins necessary for DNA synthesis occurs. During S phase replication of DNA takes place. The nucleotides get assembled and DNA molecules are synthesized. During G2phase organelles like centrioles are doubled and mitochondria, chloroplasts etc. divide.
35. (b)
Metaphase is the best time to count and study the number and morphology of chromosomes. The distinctly visible chromosome arrange themselves at the equatorial or metaphasic plate. The centromeres lie at the equational plate while the limbs are placed variously according to their size and spiral arrangement. At prophase the chromosomes appear thin and filamentous, forming a network. So they are not very clearly visible. At telophase the chromosomes uncoil and lengthen and therefore are not clearly seen. Anaphase also shows chromosomes distinctly and they can be counted. But during anaphase chromatids seperate and start moving towards opposite pole. So for counting metaphase is the best stage.
36. (b)
Meiosis involves exchange of genes between homologous chromosomes. So the gametes produced are genetically different from each other. Offsprings produced by the fusion of gametes therefore also show recombinations or genetic variations. These variations in the offsprings make organisms more adaptable to the environment and these have a definite role in evolution.
37. (d)
Meiosis II is shorter than the typical mitotic division because of the shortening of prophase of this division. The division maintains the number of chromosomes produce at the end of reduction division. Hence, it is called homotypic or equational division, though it is similar to mitosis. The main function of homotypic division or meiosis II is to separate the chromatids of univalent chromosomes which differ from each other in their linkage groups due to crossing over.
38. (a)
Number of chromatids at metaphase is two each in mitosis and meiosis. Chromatid is a half chromosome during duplication in early prophase and metaphase of mitosis and between diplotene and the second metaphase of meiosis. After these stages chromatids are called a daughter chromosomes.
39. (d)
Mitotic anaphase differs from metaphase in possessing same number of chromosomes and half number of chromatids. During anaphase of mitosis, chromosomes divide at the point of centromere or kinetochore and thus two sister chromatids are famed which are called as chromosomes. While during metaphase, chromosomes become maximally distinct due to further contraction and thus size of chromosomes is measured at mitotic metaphase.
40. (a)
In meiosis, the daughter cells differ from parent cell as well as amongst themselves due to segregation, independent assortment and crossing over. Daughter cells inhibit variations. Meiosis leads to recombinations or new combinations of genes or characters as a result of crossing over. Due to these recombinations, variations are created, which have role in process of evolution.
41. (b)
Segregation of Mendelian factor (Aa) occurs during Anaphase-I. The paired homologous chromosomes separate in meiosis-I so that each gamate receives one chromosomes of each homologous pair. During Anaphase-I chromosome divides at the point of centromere or kinetochore and thus two sister chromatids are formed, which are called as chromosomes.
42. (c)
August Weismann in 1887 predicted that the number of chromosomes must be reduced by one half during gamete formation. The two divisions of meiosis are called the first and the second meiotic divisions. In meiosis I, the number of chromosomes are reduced from diploid to haploid condition, whereas in meiosis II, the two chromatids of each chromosomes separate from each other and go to separate daughter cells, as a result the number of chromosomes remains the same as produced by meiosis -1.
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