Solutions : –
1. (d): Taxonomic keys are aids for rapid identification of unknown plants. Flora is an inventory of the plants of a defined geographical region. Herbarium is a safe place for storing specimens as well as providing a suitable atmosphere for research. A monograph is a comprehensive taxonomic treatment of a taxonomic group, generally a genus or a family, providing all taxonomic data relating to that group.
2. (b): Classification given by Bentham and Hooker is a natural system of classification. Monocots were placed after dicots; closely related families were separated; gymnosperms were placed between dicots and monocots.
3. (b): Protists include all unicellular and colonial eukaryotes except those of green and red algae. They are broadly divided into three groups – photosynthetic, slime molds and protozoans. The protistan cells are typically eukaryotic, having membrane-bound organelles like mitochondria, chloroplasts, Golgi bodies, endoplasmic reticulum, nucleus, etc. The nucleus is well-defined. The genetic material is linear DNA, enclosed by a nuclear envelope, complexed with proteins and organized into distinct chromosomes.
| 4. | Red algae | Polysiphonia |
| Liver wort | Marchantia | |
| Walking fern | Adiantum | |
| Gymnosperm | Pinus |
5. (d): Red algae or rhodophyta is an ancient group of algae with over 500 living species. They are marine except for a few fresh water species. Cell wall possesses cellulose pectic compounds and certain muco-polysaccharides called phycocolloids. Many red algae are sources for agar such as Gelidium, Gracillaria, Ceramium and Chondrus.
6. (a) : Living fossil is Gingko biloba. It is called so because it is the only living genus of order ginkgoales (a big fossilized order).
7. (b): Peripatus displays some of the characteristics of both the annelid worms as well as arthropods, besides its own typical features. Owing to its resemblance with two different phyla, they are often referred as the connecting link between annelida and arthopoda.
8. (b): Duck-billed platypus is an egg laying mammal. It is a monotreme. It lays eggs in the nests. There is no uterine gestation. Newly hatched young immature, fed on milk in abdominal pouch till fully developed. The beak is broad and flat just like a duck and hence named as duck-billed platypus.
9. (c) : The neurilemma consists of tubular sheath cells or Schwann’s cells. The function of Schwann’s cell is to produce the myelin sheath around the neuraxis (axon of a neuron). For the formation of axon sheaths, the plasma membrane of a Schwann’s cells extends as a double layer which gets wrapped around the axon many times. The membrane fuse forming the myelin sheath.
10. (d): Phallic or conglobate gland is the accessory gland which opens, near the male genital pore by phallic duct in cockroach. Its secretion forms covering of spermatophore.
11. (a) : Caryopsis is a dry single-seeded indehiscent fruit in which pericarp is fused with the testa or seed coat of the seed. It is the grain of cereals and grasses.
12. (b) : In Asteraceae, inflorescence is head or capitulum, flower is epigynous, sepals are 5 in number and are reduced to hairy pappus’, 5 epipetalous stamen with syngenesious condition bicarpellary syncarpous gynaecium, ovary inferior.
In solanaceae, flower is bisexual, pentamerous, sepals are 5 and gamosepalous, corolla have 5 petals variously shaped, 5 stamens having unequal filaments, bicarpellary syncarpous superior ovary, bilocular.
In brassicaceae, inflorescence is corymb, cruciform corolla tetradynamous androecium, bicarpellary, syncarpous gynaecium, ovary superior become bilocular due to false septum.
13. (c) : Secondary phloem or bast forms a narrow circle on the outer side of the vascular cambium. Secondary phloem does not grow in thickness because the primary and the older secondary phloem present on the outer side get crushed with the development of new functional phloem. Therefore, rings (annual rings) are not produced in secondary phloem. The crushed or non-functioning phloem may, however, have sclerenchymatous fibres called phloem or bast fibres. E.g., Jute, hemp, etc.
14. (b): Nepenthes or pitcher plant is an insectivorous plant having large pitchers of 10-45 cm in length. Leaves are alternate and modified with a foliaceous leaf base, tendrillar petiole and lamina modified into a pitcher with the leaf apex forming its lid. The lid is partly bent outwardly in such a way as to protect the opened mouth from rainfall. Insects are attracted by the gaudy color of the lid and pitcher as well as the nectar available on the rim and neck of the pitcher.
15. (b) : Cell theory was proposed in 1838 by Matthias Schleiden and by Theodor Schwann. The cell theory says that: All organisms are composed of one or more cells. All cells come from pre-existing cells. All vital functions of an organism occur within cells. Cells contain the hereditary information necessary for regulating cell functions and for transmitting information to the next generation of cells.
16. (d): Endoplasmic reticulum functions as cytoskeleton or intracellular and ultrastuctural skeletal framework by providing mechanical support to colloidal cytoplasmic matrix. Proteins and enzymes synthesised by ribosome enter the channels of rough endoplasmic reticulum both for intracellular use as well as extracellular transport.
17. (b) : Transferase is a class of enzyme that catalyse the transfer of a group of atoms from one molecule to another. The given reaction shows the involvement of transferase enzyme.
18. (b): Competitive inhibition is a reversible inhibition where inhibitor competes with the normal substrate for the active of enzyme. A competitive inhibitor is usually chemically similar to the normal substrate and therefore, fits into the active site of an enzyme and binds with it. The inhibition is thus due to substrate analogue. The enzyme, now cannot act upon the substrate and reaction products are not formed. Hence, action of an enzyme may be reduced or inhibited. Since a competitive inhibitor occupies the site only temporarily, the enzyme action is not permanently affected. The activity of succinate dehydrogenase is inhibited by malonate and is the most common example of competitive inhibition.
19. .(d): During diplotene or diplonema the synaptic forces keeping the homologous chromosomes together come to an end. The homologous chromosomes start separating (G. diplos = double; tene = thread). This is called disjunction. The synaptonemal complexes mostly disappear during diplotene. With the disappearance of the synaptonemal complexes the axial filaments become unpaired.
20. (c)
21. (d): Hydrophilic substances cannot easily diffuse across plasma membrane. Their diffusion must be facilitated by transport proteins i.e., facilitated diffusion. In facilitated diffusion special transport proteins help move substances across membranes without expenditure of ATP energy. Facilitated diffusion cannot cause net transport of molecules from a low to a high concentration as this would require input of energy. Transport rate reaches a maximum when all of the protein transporters are being used (saturation). Facilitated diffusion is very specific; it allows cell to select substances for uptake. It is sensitive to inhibitors which react with protein side chains.
22.(c) : Guttation is the process of loss of impure water (a dilute solution of different organic and inorganic substances) from uninjured or intact plant mostly margins of leaves. It occurs when transpiration rate is very low as compared to rate of water absorption. Due to this, root pressure is developed and water is pushed out through specialised pores at vein endings called hydathodes. Each hydathode is made up of group of loosely arranged achlorophyllous or colourless and parenchymatous cells called epithem. These cells help in absorbing a good percentage of inorganic and organic solutes present in the exudate. Thus, guttation is due to positive pressure in the xylem developed due to root pressure.
23.(a) : The most common symbiotic association of legume and bacteria on roots is as nodules, which are small outgrowth on the roots. The microbe Frankia is symbiont in root nodules of several non-legume plants like Casuarina and Alnus. Both Rhizobium and Frankia are free living in soil but as symbiont can fix atmospheric nitrogen.
24. (c)
25. (d): Chlorophyll molecule has a complex porphyrin ring
(head) to which is attached a long hydrophobic phytol (C28H39) chain (tail). The metal constituent of the molecule, the magnesium, is incorporated in this ring. Different chlorophylls have the following formulae — chlorophyll a – (C55H7205N4Mg), chlorophyll b – (C55H7006N4Mg), chlorophyll c (C35H3205N4Mg), chlorophyll d – (C54H7006N4Mg).
26. (a) : The value of diffusion pressure deficit is equal to osmotic pressure of solution in a cell minus wall pressure. Diffusion is the movement of particles of gases, liquids and solids from a region of higher free energy to region of lower free energy. It is more rapid in gases as compared to liquids as the density Of gases are low than that of liquids. Imbibition is the absorption of water by solid particles of an adsorbent substance without forming a solution.
27. (a) : Photorespiration is the respiration process that occurs in green cells in presence of light. Photorespiration involves three organelles i.e., chloroplast, peroxisomes and mitochondria. Respiratory substrate is a 2 carbon compound glycolic acid. The process of photorespiration is cyclic. RuBP carboxylase at high 02 concentration, functions as oxygenase enzyme. The enzymes involved in photorespiration are present in the three organelles that are the sites of the process.
28. (d): The equation of photosynthesis may be represented as
6C02 + 12H20 → C6H1206 + 6H20 + 602 t
No. of C02 molecules utilized = 6
No. of H20 molecules utilized = 12
No. of C6H1206 (sugar) molecules produced = 1
No. of H20 molecules produced = 6
No. of 02 molecules produced = 6
Hence, total number of C02, H20, 02 and sugar utilized and produced = 6 + 12 + 1 + 6 + 6 = 31.
29. (c) : Last step of aerobic respiration is oxidation of reduced coenzymes, i.e., NADH2 and FADH2 by molecular oxygen through FAD, COQ (ubiquinone), Cyt. b, Cyt. Cl, Cyt. c, Cyt. a and Cyt. ’73. Two hydrogen atoms or electrons move from NADH2 and travel through this ETS chain and finally combine with half molecule of 02 to form water and hence it is known as terminal oxidation.
30. (a) : Electron transport system is a chain of electron carriers that is present in the inner mitochondrial membrane that carry the electron from NADH and FADH2 produced in mitochondrial matrix to the final acceptor oxygen, resulting in formation of H20. It is essential to release and utilize the energy stored in NADH and FADH2.
Respiratory quotient is the ratio of volume of C02 evolved to the volume of 02 consumed, i.e.
R.Q = Volume of CO2 evolved/Volume of O2 consumed
31. (a) : Pyruvate dehydrogenase is an enzyme that is needed for the conversion of pyruvate into acetyl CoA. This enzyme is present in mitochondrial matrix.
32. (a)
33. (d): ABA is a 15-C sesquiterpine multirole plant hormone which acts as an inhibitor because it opposes the growth promoting effect of auxin, gibberellin and cytokinin. It is not a flowering hormone but florigen is a flowering hormone.
34. (a) : Wharton’s duct is the duct of submandibular salivary gland, opening into the mouth at the side of the frenum linguae.
35. (a) : Fat stores more energy per gram than any other cell constituent. It can be stored in adipose tissue for long term use like in case of hibernation.
36. (d) : Amylase breaks starch into maltose disaccharides.Lactase breaks down lactose to give galactose and glucose.Maltase breaks down maltose into glucose monomers.Invertase breaks down sucrose into fructose and glucose.Thus, the correct answer is ‘A-amylase, B-lactase, C-maltase, D-invertase.’
37. (b): In lungs, the air is separated from the venous blood through squamous epithelium and endothelium of blood vessel. The walls of the capillaries and of the alveoli each consists of a single layer of flattened squamous epithelial cells separated from one another by a thin basement membrane. As a result, the barriers between the air in an alveolus and the blood in its capillaries is only about 0.5 mm.
38. (b): The exchange of gases in the alveoli of the lungs takes place by simple diffusion. The exchange of gases between the alveoli and blood in the lung is the result of difference in partial pressure of respiratory gases. partial pressure of 02 in alveolar air is 100 mm Hg and it is only 40 mmHg in arterial capillaries of lungs. Therefore oxygen from the alveolar air rapidly diffuses into the blood of capillaries. Same thing happens in case of C02.
39. (c) : A normal electrocardiogram (ECG) is composed of a P wave, a QRS wave and a T wave. The P wave is a small upward wave that indicates the depolarisation of the atria. This is caused by the activation of SA node.
40. (a) : Individuals with blood group B possess antigen B in RBCs and antibodies in blood plasma. They can give blood to individuals with blood groups B and AB and can receive blood from individuals with B and O blood groups.
41. (a) : About 65% of the glomerular filtrate is normally reabsorbed in the proximal convoluted tubule before reaching the loop of Henle. Glucose, amino acids, vitamins, hormones, sodium, potassium, chlorides, phosphates, bicarbonates, much of water and some urea from the filtrate are absorbed. Glucose and amino acids are reabsorbed by secondary active transport.
42 (b) : Dialysis is done in the condition, when person is suffering from uremia, an excess of the nitrogenous end products of protein and amino acid metabolism in the blood. It shows the signs of chronic renal failure. Dialysis is the process of separating crystalloids and colloids in solution by the difference in their rates of diffusion through a semipermeable membrane, crystalloids pass through readily, colloids very slowly or not at all.
43. (d)
44. (d): Tarsals, femur, metatarsals and tibia are bones of the legs which are involved in running during chasing the ball by cricket player.
45. (a) : Ilium is the largest of three bones that make each half of the pelvic girdle. Ischium is the most posterior part while pubis is the anterior most part of the three pelvic bones.
46. (d)
47. (c) : Bowman’s gland is any of the tubular and often branched glands occurring beneath the olfactory epithelium of the nose. It is also called olfactory gland. It secretes mucous to spread over the epithelium to keep it moist. The mucous also protects the cells from dust and bacteria.
48. (d): Diabetes insipidus is the inability of the kidneys to respond to ADH or vasopressin. Vasopressin is released from posterior pituitary in response to a fall in the water content of blood plasma and leads to an increase in the permeability to water of the distal and collecting tubules of the nephron in the kidney. As a result of which the reabsorption of water from the glomerular filtrate is increased. Diabetes insipidus is characterized by micturating dilute urine several times a day.
49. (a) : Graves’ disease or Basedow’s disease or Parry’s disease or exophthalmic goitre is a thyroid enlargement (goitre) in which the thyroid secretes excessive amount of thyroid hormone. It is characterised by exophthalmia (portrusion of eye balls because of fluid accumulation behind them), loss of weight, slight rise in the body temperature, excitability rapid heart beat, nervousness and restlessness.
50. (b): Process of parturition is induced by both nervous system and hormones secreted by the endocrine glands of the mother. The signals for child birth (parturition) originate from the fully developed foetus and placenta which induce mild uterine contractions called foetal ejection reflex. This causes quick release of oxytocin from the maternal posterior lobe of pituitary gland which induces labour pains.
51. (b): In mammals, scrotal sac or scrotum acts as a thermoregulator, maintaining the testis at a temperature 2o C lower than that of the body. It protects the sperms against relatively high temperature which is incompatible to spermatogenesis. As sperms present in seminiferous tubule which can be destroyed by higher temperature, it may result in sterility.
52. (c) : In the maturation phase of spermatogenesis spermatozoa is formed from primary spermatocyte. In this phase first maturation division is reductional and produces two secondary spermatocyte. The latter divides by equational division (second maturation division) to form four haploid spermatids Spermatids recieve nourishment from the sertoli cells to form spermatozoa or sperms (called spermiogenesis).
53. (a) : Birth control pills contain a combination of synthetic progestins (acting like progesterone) and estrogens so called combined pills. These pills inhibit secretion of FSH and LH from anterior lobe of pituitary gland so these inhibit ovulation from ovary. Progesterone also affects tubal motility which delays transport of sperm and ova.
54. (d): Gonorrhoea is a bacterial infection that is sometimes known as the ‘clap’. It is easily transmitted through vaginal anal and oral sex. It commonly infects the genitals Of men and women. It is among the most common curable sexually transmitted diseases in the world caused by the Graff: negative bacterium called Neisseria gonorrhoeae.
55. (d): Sterilization is surgical technique leaving a male or female unable to procreate. It is a method of birth control Common sterilization methods include the following:
Vasectomy in males : The vasa deferentia, the tubes which connect the testicles to the prostate, are cut and closed This prevents sperm produced in the testicles to enter the ejaculated semen (which is mostly produced in the prostate and the seminal vesicles).
Tubal ligation in females : The Fallopian tubes, which allows the sperm to fertilize the ovum and would carry the fertilised ovum to the utreus, are closed.
Hysterectomy in female : The utreus is surgically removed, permanently preventing pregnancy and some diseases, such as uterine cancer. Castration in males : Castration is the removal of testes. In childhood it causes failure of development but when done in adult life it produces less marked physical changes and inevitably causes sterility but it need not cause impotence or loss of sexual desire.
56. (b)
17.(c)
58. (b): In water plants like water hyacinth and water lily, flowers emerge above the water level and are pollinated by insects.
59.(d)
60. (a)
61. (b)
62. (d): In birds and some reptiles both the sexes possess two sex chromosomes but unlike human beings the females contain heteromorphic sex (AA + ZW) while the males have homomorphic sex chromosomes (AA + ZZ). Because of having heteromorphic sex chromosomes, the females are heterogametic (female heterogamety) and produce two types of eggs, (A + Z) and (A + W) whereas male gametes or sperms are of one type (A + Z). This type of sex determination is observed in birds and some reptiles.
63. (c) : The change in single base pair may not change the phenotype due to degeneracy of codon.
64.(a) : Incomplete dominance is the phenomenon where none Of the two contrasting alleles or factors is dominant. Carl Correns reported incomplete dominance in Antirrhinum majus and Mirabilis jalapa. In both the cases there are two types of flower colour in pure states red and white. When the two types of plants are crossed the hybrid or plants of Fl generation have pink flowers. Mutation in dominant allele results in mutant allele which produces faulty products. The unmodified functional wild type allele that represents the original phenotype behaves as dominant allele. The modified or mutated nonfunctional allele behaves as recessive allele. This results in incomplete dominance.
65. (a) : DNA sequence -C GAT TACA G
RNA sequence -G C U AA U G U C
66. (a) : Lactose is the substrate for the enzyme beta-galactosidase and it regulates switching on and off of the operon. It is termed as inducer.
67.(b): In directional Selection (progressive Selection), the population changes towards one particular direction. It means this type of selection favours small or large-sized individuals and more individuals of that type will be present in next generation. The mean size of the population changes. For example, evolution of DDT resistant mosquitoes, industrial melanism in peppered moth (Biston betularia) and evolution of giraffe.
68. (a) : Galapagos Islands are a chain of 14 islands in the pacific Ocean on the west coast of South America. Charles Darwin visited these islands during his famous voyage on HMS Beagle (name of his ship) in 1853. The flora and fauna of these islands resemble with those of the South American mainland with which the Galapagos Islands were once connected. However, Darwin’s finches (birds of Galapagos Islands) influenced Darwin to think about the evolutionary change. These birds designated as Darwin’s finches by Dr. David Lack (1947) do not resemble the birds of the South American species. These finches were the first to reach the Galapagos Island as migrants from the mainland (South America). When they reached the islands, they faced many problems for obtaining food. They had to change their feeding habits. The diversity in food habits in turn produced different types of beaks among these finches.
69. (b)
70. (d) : Dengue fever and yellow fever is caused by an arbovirus (arthropod born virus). The diseases are caused due to the transmission of the virus by Aedes aegypti mosquito.
71. (d) : Interferons are a type of cytokine barriers. Interferons are the proteins secreted by the virus infected cells, which protect non infected cells from further viral infection.
72. (a)
73. (d) : In poultry industry the production of hatching eggs is more expensive than the production of market eggs mainly because not all the eggs produced by hatchery flocks are acceptable for incubation and they are produced by the mating of male with female. No male and female are involved and no embryo is formed in market eggs, it is suitably produced by giving hormone injection.
74. (b) : Calcitonin is a thyroid hormone secreted by C-cells, which regulates the concentration of calcium and phosphorus in the blood. It has nothing to do with treatment of infertility.
75. (c) : Bacillus thuringiensis — Production of Bt toxin
Rhizobium meliloti — Incorporation of nif gene
Escherichia coli — Production of human insulin
Pseudomonas putida — Scavenging of oil spills
Trichoderma — Production of chitinases.
76. (d)
77. (b): Flavr Savr variety of tomato is a transgenic crop. “Flavr Savr” are genetically engineered tomatoes which express delayed softening. The production of enzyme polygalacturonase which promotes softening of fruit as it is responsible for the breakdown of cell wall pectin is reduced in these transgenic tomatoes.
78. (b)
79. (b): ‘Taq and ‘Pfu’ are thermostable enzymes, which are isolated from thermophilic bacteria. They are DNA polymerases in nature, which are widely used in polymerase chain reactions.
80. (a)
81. (c)
82. (a)
83. (d) : Organisms found in fresh water have a problem of excess internal water because of endosmosis. Organisms found in ocean or saltish water have a problem of low internal water content due to exomosis. For aquatic organisms the quality (chemical composition, pH) of water becomes important. Many freshwater animals cannot live for long in sea water and vice versa because of the osmotic problems they would face.
84. (a)
85. (a) : Of all the ecosystems, ocean is the largest and most stable ecosystem. Aquatic life is protected from vigorous climates and weather that are climatic conditions, problem of water supply, food, fire and artificial forces such as industrialization, farming and grazing are lacking in the oceans. The sea is continous and not separated as land and freshwater habitats.
86. (b): Biosphere reserves, National park and wild life sanctuaries are all protected areas but differ from each other in some ways. National parks are reserved for betterment of wild life. Cultivation, grazing, forestry and habitat manipulations are not allowed. Sanctuaries are tracts of land with or without lake where wild life can take refuge. Harvesting of timber, collection of forest products, tilling of land, private ownership of land etc., are allowed. Biosphere reserves are multipurpose protected areas which are meant for preserving genetic diversity in representative ecosystems of various national biomass and unique biological communities by protecting wild life, traditional life style of tribals and domesticated plant/animal genetic resources. Each biosphere reserve has 3 zones — natural zone (where no human activity is allowed), buffer zone (limited human activity is allowed like education, research) and transition zone (has different parts like agriculture, tourism, and restoration regions).
87. (d): Non-native or alien species are often introduced iddvertently for their economic and other uses. They often become invasive and drive away the local species. These species are considered to be second major cause of extinction of species (the first being habitat destruction, Water Hyacinth (Eichhornia crassipes) was introduced in Indian water to reduce pollution. It has clogged water bodies including wetlands at many places resulting in death of several aquatic plants and animals. Lantana camara has replaced many species in forest of U.P. and M.P. African catfish, Clarias gariepinus, has been illegally introduced for aquaculture in India. It is threatening native Catfishes (e.g., Clarias bacterachus) of Indian rivers.
88. (a)
89. (a) : Chipko movement was started under the leadership of Mr. Sunderlal Bahuguna. He presented a plan regarding ban on tree felling in Himalayas at the United Nations Environmental Programme (UNEP) meeting held in London in 1982.
90. (a) : Photochemical smog is grey or yellow brown opaque smog having oxidising environment with little smoke. Photochemical smog contains secondary pollutants or photochemical oxidants. It was first reported over Loss Angels in 1940s. Photochemical smog is formed at high temperature over cities and towns due to still air, emission of nitrogen oxides and carbohydrates from automobile exhausts. Nitrogen dioxides splits into nitric oxide and nascent oxygen. Nascent oxygen combines with molecule oxygen to form ozone. Ozone reacts with carbohydrates to form aldehydes and ketones. Nitrogen oxides, oxygen and ketones combine to form peroxy-acyl-nitrates (PAN) In areas with intense solar radiations, photoelectrical smog forms brown air.
91. (b) : Phyllode is a modified leaf rachis or petiole. It is xerophytic adaptation. It performs photosynthesis. It reduces rate of respiration in xerophytes. Cladode and phyllocalde are modified stem. Corm is an underground storage organ.So, the correct answer is ‘Phyllode’
92. (b) : Characteristic features of the family Fabaceaeare –
1. Leaves are usually alternate and compound.
2. The flowers are zygomorphic and in general, have five fused sepals.
3. The petals are also five free.
4. The presence of having a short usually cup-shaped hypanthium.
5. Stamens ten in number, superior ovary and curved style.
6. Placentation marginal.
Flowers of Fabaceaedo not show actinomorphic nature, twisted aestivation and gamopetaly. Thus, the correct answer is option B.
93. (b) : The correct option is B More Stomata on lower surface
In dorsiventral leaf, the upper epidermis is covered with thick cuticle and lacks stomata and the lower epidermis is light green, covered with thin cuticle and has many stomata.The leaves usually orient at an angle to the main axis and held perpendicular (normal) to the direction of sunlight. Example, leaves of dicots.
94. (a) : During secondary growth in dicot roots, phellogen or cork cambium produce periderm. The cork cambium produces cork or phellem towards the periphery. Secondary cortex (secondary phloem) is produced by the cambium and while periderm is developed by phellogen. Thus, the cork cambium produces phelloderm on inside and phellem or cork on outside.
Thus, the correct answer is option A.
95. (a) : Golgi body is the series of flattened stacks which has two faces cis face towards the ER side and trans face opposite of ER. The main function of Golgi complex is the packaging of materials for secretion. The Golgi apparatus is a major collection and dispatch station of protein products received from the endoplasmic reticulum (ER). The Golgi apparatus is also involved in lipid transport and lysosome formation. It also involved in the synthesis of cellulose and hemicellulose. Thus, the correct answer is option A.
96. (d) : Correct option is D. Ability to multiply by a fission like process
Chloroplast, chromoplast, and leucoplast are all three are types of plastids.
Leucoplast is a colourless plastid, involved in the storage of starch lipid and proteins. Being colourless, leucoplasts are devoid of any pigments. (This option A is wrong).
Chloroplasts are green coloured plastids containing thylakoids and photosynthetic pigment chlorophyll. They are involved in the photosynthetic production of carbohydrates.
Chromoplasts are plastids responsible for pigment synthesis. They give distinctive colours to different fruits, flowers and ageing leaves in plants.All the plastids (chromoplast, chromoplast and leucoplast) are thought to be descended from symbiotic prokaryotes and therefore, they all divide by fission like process.Hence the correct answer is ‘Ability to multiply by a fission like process’.
97. (d) : RuBisCO is very important in biology and ecology because it catalyzes the primary chemical reaction by which inorganic carbon permanently enters the biosphere. RuBisCO is also the most abundant protein in leaves and the most abundant protein on Earth. Collagen is the most abundant protein (structural protein) in the animal world and is the structural component of most animals.So the correct option is ‘Collagen is the most abundant protein in the whole of the biosphere and RuBisCo is the most abundant protein in the animal world.’
98. (d) : There are more than thousand of biomolecules involve in living organisms in various biological processes. Some are vitamins, hormones, enzymes, ATP, carbohydrates, lipids, nucleic acids and proteins. Out of these main carbohydrates, proteins, lipids and nucleic acid are main biomolecules which play a vital role in living systems and mainly responsible for almost all biochemical processes. The biological molecules or biomolecules are involved in metabolic activities of living bodies such as plants and animals. Most of the biomolecules in the living cell have some broad functions like:
1. They are essential to cellular and body structure.
2. They act as energy-rich fuels during cellular respiration.
3. The molecules are used to carry information of controlling growth and biological characteristics from one generation to another.4. They are good catalytic agents for the various chemical processes occur in cell and living body.
99. (d) : In pachytene, the bivalent chromosomes clearly appear as a tetrad.
While these chromosomes were formed in the zygotene stage of the prophase- I by the process of association of synaptonemal complexes called synapsis.
100. (b) : During the first prophase of meiosis I, there are five sub – stages : Leptotene, Zygotene, Pachytene, Diplotene and Diakinesis. The stage next to zygotene is Pachytene, wherein the homologous chromosomes shorten, thicken and separate into four distinct chromatids joined at the centromeres.So, the correct answer is ‘Pachytene’
