AIIMS Special 2014 – Practice Questions on Assertion & Reason

Direction : In the following questions (1-75), a statement of assertion (A) is followed by a statement of reason (R). Mark the correct choice as :
(a) If both assertion and reason are true and reason is the correct explanation of assertion.
(b) If both assertion and reason are true but reason is not the correct explanation of assertion.
(c) If assertion is true but reason is false.
(d) If both assertion and reason are false.
1.Assertion : In living organisms, increase in mass and increase in number of individuals are twin characteristics of growth.
Reason : Multicellular organisms grow by cell division or multiplication.
2. Assertion : Viruses take over the host machinery to replicate themselves.
Reason : Viruses are non-cellular organisms characterised by an inert crystalline structure.
3. Assertion : Sexual reproduction in liverworts takes place by gemmae.
Reason : Gemmae are green, multicellular, sexual buds, which develop in small receptacles called gemma cups located on the thalli.
4. Assertion : Aschelminthes are called pseudocoelomates.
Reason : In Aschelminthes, the mesoderm is present as scattered pouches in between the ectoderm and endoderm.
5. Assertion : The fruit of the Solanaceae family is called legume.
Reason : Legume fruit develops from a inferior bicarpellary and bilocular ovary having parietal
placentation.
6. Assertion : Both apical meristem and intercalary meristem are called primary meristems.
Reason : These meristems appear early in life of a plant and helps in the formation of primary plant body
7. Assertion : The intestine of earthworm between 27 segment and upto 23-35 segments infront of anus contains internal median fold of dorsal wall called typhlosole.
Reason : Typhlosole increases the effective area of absorption in the intestine of earthworm.
8. Assertion: Endoplasmic reticulum, Golgi complex, lysosomes and vacuoles together form the endomembrane system.
Reason : Functions of these organelles are coordinated, so they are considered together as a system.
9. Assertion : Collagen is the most abundant protein in the whole biosphere.
Reason : Collagen is present in almost all animal and plant cells.
10. Assertion : Enzymes generally function in a narrow range of temperature.
Reason : Low temperature renders the enzyme in a temporarily inactive state and high temperature destroys enzymatic activity.
11. Assertion : G1 phase corresponds to the interval between mitosis and initiation of DNA replication.
Reason : During G1 phase, cells are metabolically inactive.
12. Assertion : Pinus seeds cannot germinate and establish without the presence of mycorrhizae.
Reason : The fungus provides minerals and water to the roots and roots provide sugars and N-containing compounds to the mycorrhizae.
13. Assertion : Enterogastrone is also called gastric inhibitory peptide (GIP).
Reason : It inhibits gastric secretion and motility and slows down gastric contraction.
14. Assertion : Pons region of the brain moderates the functions of the respiratory rhythm centre. Reason : Respiratory rhythm centre is present in the medulla region of the brain.
15. Assertion : Heart is autoexcitable, but its functions
Reason : Sympathetic nerves decrease the rate of heart beat and parasympathetic nerves increase the rate of heart beat.
16. Assertion : Urine is a light yellow coloured water fluid with a slightly acidic pH.
Reason : Urine contains the pigment urochrome, which is a breakdown product of haemoglobin from worn out red blood corpuscles.
17. Assertion : The portion of the myofibril between two successive ‘Z’ lines is called a sarcomere, which is the functional unit of contraction.
Reason : The junction between a sensory neuron and the sarcolemma of the muscle fibre is called the neuromuscular junction.
18. Assertion : The 8th, 9th and 10th pairs of ribs of our body are called vertebrochondral or false ribs. Reason : These ribs do not articulate directly with the sternum, but join the seventh rib with the help of cartilage.
19. Assertion : Membrane of a non-conducting neuron is positive on the outside and negative inside. Reason : At rest, the axonal membrane is comparatively more permeable to sodium ions (Na+) and nearly impermeable to potassium ions (K+).
20. Assertion : Thyroid hormones of thyroid gland control the metabolism of carbohydrates, proteins and fats. Reason : Thyroid gland secretes a proteinaceous hormone called parathyrocalcitonin, which regulates the metabolism.
21. Assertion : The innermost wall layer of macrosporangium is called tapetum.
Reason : Tapetum nourishes the developing embryo in the ovule.
22. Assertion : Rhizomes, present in ginger, take part in vegetative propagation.
Reason : Rhizomes are underground adventitious roots which can form new plants.
23. Assertion : The secondary growth occurs in most of the dicotyledonous roots and stems.
Reason : Secondary growth increases the girth of the organs by the activity of the vascular cambium and cork cambium.
24. Assertion : FSH acts on Sertoli cells of epididymis to secrete an androgen binding protein (ABP) and inhibin.
Reason : ABP concentrates testosterone in epididymis and inhibin suppresses FSH synthesis.
25. Assertion : Mendel’s law of segregation is also known as principle of purity of gametes.
Reason : The segregation of the two Mendelian factors of a trait results in gametes receiving only one factor out of a pair.
26. Assertion : Ranunculus flabellaris shows heterophylly with dissected leaves inside water and entire leaves outside.
Reason : Changes in the phenotype in response to different environmental factors is due to plasticity.
27. Assertion : Split genes are the segments of DNA which can move from one place in the genome to other.
Reason : Split genes possess repetitive DNA, either similar or inverted, at their ends which aid in movement.
28. Assertion : Stems of some plants of arid region carry out photosynthesis.
Reason : Stem of these plants are modified into flattened or fleshy cylindrical structures which contain chlorophyll.
29. Assertion : Marijuana is a product obtained from hemp plant.
Reason : It is obtained from the dried flowers and top leaves of the female plants of Cannabis sativa.
30. Assertion : Meristem culture is the cultivation of axillary or apical shoot meristems.
Reason : Meristem culture involves the development of an already existing root meristem and subsequently the generation of shoots from developed roots.
31. Assertion : Dosa and Idli are the fermented preparations of rice and black gram.
Reason : CO2 produced during fermentation causes puffing up of the dough.
32. Assertion : Endonucleases remove nucleotides from the ends of the DNA.
Reason : Exonucleases makes cuts at specific positions within the DNA.
33. Assertion : “Rosie”, the first transgenic cow, produced human protein enriched milk.
Reason : The milk contained the human alphalactalbumin and was more balanced product for human babies than natural cow milk.
34. Assertion : Outcrossing is the best breeding method for animals that are below average in milk production.
Reason : Outcrossing involves mating of superior males of one breed with females of another breed.
35. Assertion : Vertical distribution of different species occupying different levels is called stratification.
Reason : Trees occupy top vertical strata, shrubs the second, herbs and grasses occupy the bottom layers.
36. Assertion : The sharp decline in dissolved oxygen in the water body, causes mortality of fish and other aquatic creatures.
Reason : Micro-organisms involved in bio-degradation of organic matter in the receiving water body consume a lot of oxygen.
37. Assertion : Colostrum provides active immunity to new born infant.
Reason : It contains IgD as the major immunoglobulin.
38. Assertion : The concentration of ozone over Antarctica is decreasing leading to thinning of ozone layer.
Reason : Ozone depleting substances react with ozone present in troposphere and destroy the same.
39. Assertion : Diaphragms, cervical caps and vaults are inserted into the female reproductive tract to cover the cervix during coitus.
Reason : They prevent conception by blocking the entry of sperms through the cervix.
40. Assertion : Labia majora are two large fleshy folds of skin which form the boundary of vulva.
Reason : Labia majora are homologous to membranous urethra of male.
41. Assertion : The central cell is the largest cell of the embryo sac.
Reason : It has a highly vacuolate cytoplasm, which is rich in reserve food and Golgi bodies.
42. Assertion : In organisms exhibiting internal fertilisation, the male gamete is motile.
Reason : In such organisms, the number of sperms produced is large.
43. Assertion : Grasshopper represents XO type of sex determination.
Reason : In grasshopper, males have only one X-chromosome besides the autosomes, whereas females have a pair of X-chromosomes.
44. Assertion : The RNA polymerase l transcribes rRNAs except 5S rRNA.
Reason : The RNA polymerase III transcribes tRNA, 5SrRNA and some snRNAs.
45. Assertion : The thorns and tendrils of Bougainvillea and Curcurbita show homology.
Reason : Both structures arise in the axillary position.
46. Assertion : B-lymphocytes produce antibodies that regulate humoral immunity.
Reason : Humoral immunity provides defence against all pathogens including fungi and protozoa.
47. Assertion : The germplasm is evaluated so as to identify plants with desirable combination of characters.
Reason : The entire collection of plants/seeds having all diverse alleles for all gene is called germplasm.
48. Assertion : The large holes in Roquefort cheese are due to production of large amount of CO2 by a bacterium called Propionibacterium sharmanii.
Reason : The Swiss cheese are ripened by growing a specific fungi on them, which gives them a particular flavour.
49. Assertion : Adenosine deaminase (ADA) deficiency cannot be cured completely by enzyme replacement therapy.
Reason : The permanent cure for this disease is the gene isolation from bone marrow cells producing ADA and its introduction into cells at early embryonic stages.
50. Assertion : Primary succession takes very long time.
Reason : Soil is absent at the time of beginning of primary succession.
51. Assertion : A glycosidic bond is formed by linkage of individual monosaccarides.
Reason : Formation of glycosidic bond leads to loss of a water molecule.
52. Assertion : Sickle-cell anaemia can be transmitted from parents to offspring when both the partners are carriers for the gene or when one is carrier and other has the disorder.
Reason : Sickle-cell anaemia is an autosomal dominant disorder.
53. Assertion : Parthenocarpy can be induced in fruits through the application of growth hormones.
Reason : Parthenocarpic fruits develop without fertilization and are seedless.
54. Assertion : A widely used diagnostic test for AIDS is enzyme linked immunosorbent assay (ELISA). Reason : Western blotting test is employed for confirmation of ELISA negative cases.
55. Assertion : Logistic growth model of population is considered more realistic.
Reason : Resources for growth for most animal populations are finite and become limiting sooner or later.
56. Assertion : Cell growth causes disturbance in the ratio between nucleus and cytoplasm.
Reason : Cell division restores the nucleo-cytoplasmic ratio following growth.
57. Assertion : The symplastic movement of water occurs exclusively through intercellular spaces and walls of the cells.
Reason : The symplast system of adjacent cell walls is continuous throughout the plant, except at the casparian strips of endodermis in roots.
58. Assertion : Vasopressin is also called as anti-diuretic hormone (ADH).
Reason : Vasopressin stimulates the reabsorption of water and electrolytes by the distal convoluted tubules and thereby reduces loss of water through urine.
59. Assertion : The pancreatic juice contains inactive
enzyme trypsinogen which acts on proteins in its active form.
Reason : Trypsinogen is activated into active trypsin by an enzyme, enterokinase secreted by the intestinal mucosa.
60. Assertion : The F1 head piece is an integral membrane
protein complex and contains the site for synthesis of ATP from ADP and inorganic phosphate.
Reason : The F0 is a peripheral membrane protein
complex that forms the channel through which protons cross the inner membrane.
61. Assertion : Gibberellin is also called as the stress hormone.
Reason : Its production is stimulated by drought, water logging and other adverse environmental conditions.
62. Assertion : Hatch and Slack pathway is also known as C4 pathway.
Reason : In C4 plants, first stable photosynthetic product is 4-carbon phosphoglyceric acid.
63. Assertion : Presence of large amounts of nutrients in water causes algal bloom.
Reason : Algal bloom causes deterioration of the water quality and may lead to fish mortality.
64. Assertion : The openings of the right and the left ventricles into the pulmonary artery and the aorta respectively are guarded by the semilunar valves.
Reason : These valves in the heart allow the flow of blood in both the directions.
65. Assertion : The descending limb of loop of Henle is impermeable to water but permeable to electrolytes.
Reason : The glomerular filtrate dilutes as it passes down the descending limb of loop of Henle.
66. Assertion : Synovial joints help in locomotion and many other movements.
Reason : Synovial joints are characterised by the presence of a fluid-filled synovial cavity between the articulating surfaces of the two bones.
67. Assertion : Cochlea is the organ of hearing.
Reason : The organ of Corti is located on the basilar membrane inside cochlea and contains hair cells that act as auditory receptors.
68. Assertion : The common ascomycetes are mushrooms, bracket fungi or puffballs.
Reason : Ascomycetes grow in soil, on logs and tree stumps and in living plant bodies as parasites.
69. Assertion : Adipose tissue is a type of loose connective tissue located mainly beneath the skin.
Reason : The cells of adipose tissue are specialised to store fats.
70. Assertion : ZIFT is useful for females who cannot produce ovum.
Reason : ZIFT involves transfer of zygote, formed inside donor, into the Fallopian tube of the recepient.
71. Assertion : Placenta acts as a temporary endocrine tissue.
Reason : Placenta produces hormones such as hCG, LH, relaxin and progesterone.
72. Assertion : RNAi takes place inside all prokaryotic organisms as a method of cellular defense.
Reason : RNAi involves silencing of tRNA which prevents translation.
73. Assertion : Pyramid of energy is always upright.
Reason : When energy flows from a particular trophic level to the next trophic level, some energy is always lost as heat at each step.
74. Assertion : In codominance, both alleles are expressed in a heterozygous condition.
Reason : In codominance, alleles blend to produce a new phenotype.
75. Assertion : Visceral muscles show alternate light and dark striations.
Reason : The light bands contain myosin whereas dark bands contain actin.
Answers

Leave a Reply

Your email address will not be published. Required fields are marked *