CBSE Medical Entrance Exam., 2009
40. Assertion (A) : The direction of maturation of flower in racemose
inflorescence is acropetal or cen-tripetal.
Reason (R) : Sieve-tube cells contain nuclei in their cytoplasm.
(A) (B) (C) (D) (E)
ANSWERS WITH HINTS
(Continued on Page 1184)
Physics
1. When an object is placed at the focus of a convex mirror, it is imaged at infinity.
—T/F 2. The ratio of de-Broglie wavelength of an electron and a proton moving with same kinetic energy is 1840 .
—T/F 3. Abulletisfiredfromarifle.Ifthe rifle recoils freely, the kinetic energy of the rifle is less than that of the bullet.
—T/F 4. Coloured glass appears white after being crushed
into fine powder.
—T/F 5. Pressure exerted by one mole of oxygen is equal to that by one mole of hydrogen when their temperature and volume are same.
—T/F 6. The laser is a source of ultrasound.
—T/F 7. In an electrolyte solution, the electric current is mainly
due to the movement of free electrons.
—T/F 8. A body can describe a vertical circle with any velocity.
—T/F 9. According to Kepler’s second law, the radius vector to aplanetfromthesunsweepsout equal areas in equal intervals of time. This law is a consequence of con-servation of linear momentum.
—T/F 10. If two slits in Young’s double slit experiment are illu-minated by two identical monochromatic sources of light emitting the same wavelength, no interference pattern will be observed.
—T/F 11. Theratio of the velocity of sound in hydrogen (γ = 7/5) to that in helium (γ = 5/3) at the same temperature is
21/5.
—T/F 12. X-rays are deflected by magnetic field.
—T/F 13. 300 gram of water at 25°C is added to 100 gram of ice at 0°C. The final temperature of the mixture is – 1·25°C.
—T/F 14. On refraction the frequency of light gets changed.
—T/F
15. A lorry and a car moving with the same kinetic energy are brought to rest by application of brakes which provide equal retarding force. Both come to rest in equal distance.
—T/F
Chemistry
16. A compound having composition 4KCN.Fe(CN)2 is a double salt and gives the test of Fe2 + and CN– ions.
—T/F 17. Atoms of an element having different number of
neutrons are known as isotones.
—T/F 18. The equilibrium Cr2O72– CrO42– will exist in
acidic medium.
—T/F 19. The formal charge on each hydrogen atom in
ammo-nium ion (NH4+) is equal to zero.
—T/F 20. The decreasing order of acidic strength of boron
halides is as
BBr3 > BCl3 > BF3
—T/F 21. Ethyl alcohol (C2H5OH) is a covalent molecule and
hence it is insoluble in water.
—T/F 22. R—C ≡ N and R—N →—— C constitute a pair of
com-pounds which are tautomeric to each other.
—T/F 23. The coordinate covalent bond formed between two
atoms is always non-polar in nature.
—T/F 24. Photochemical chlorination of alkanes starts with the
homolytic fission of Cl—Cl bond.
—T/F 25. The metal ions whose chlorides have high values of solubility products (Ksp) are kept in first group of qualitative analysis of basic radicals.
—T/F 26. Ethyne is more acidic than propyne.
—T/F 27. Methanoic acid gives silver mirror test with Tollen’s reagent and ethanoic acid does not respond to this test.
—T/F 28. T-shape geometry is possible if a molecule or ion has
three bond pairs and two lone pairs of electrons.
—T/F
29. Bothethanolandethanal undergo a haloform reaction when treated with a solution of iodine in NaOH.
—T/F 30. The dipole moment of NH3 molecule is higher than
that of NF3.
—T/F
Zoology
31. Granulesofcalcium carbonate in vertebrate macula is called otolith.
—T/F 32. The right cerebral hemisphere in humans is used for
language, speech and mathematical calculations.
—T/F 33. Tumours of muscles are called osteofibroma.
—T/F 34. Age-related memory loss affects short-term memory
more than long-term memory.
—T/F 35. The statocysts in invertebrates perceive the direction of the force of gravity and function as the organ of orientation and equilibrium.
—T/F 36. Restriction fragment length polymorphism (RFLP) analysis is performed on body tissue or fluid samples to match suspect and victim in a crime.
—T/F 37. Sutures are the fusion lines of junctions between
adjacent bones of the skull.
—T/F 38. Recessive alleles are expressed in heterozygous condition, while dominant alleles are expressed in the homozygous condition.
—T/F 39. Fraternal twins are developed as a result of
fertiliza-tion of a single ovum.
—T/F 40. The first humans were Homo habilis, appeared about
1·5 million years ago.
—T/F 41. Digestion within a digestive tract of humans is
extra-cellular.
—T/F 42. Fibroblasts secrete a living matrix which contains
collagen, reticular, or elastic fibres.
—T/F 43. Thebreathingcentreinthebrainresponds to changes
in the carbon dioxide concentration of the blood.
—T/F 44. Aging may result from an accumulation of genetic mutations, free radicals, or waste products as well as
crosslinking of proteins, development of autoimmu-nity, and the presence of an internal biological clock.
—T/F 45. In the wall of caecum and colon, the longitudinal mus-cular layer is thickened along three lines forming the taeniae.
—T/F
Botany
46. Doubling of chromosomes during S-phase of inter-phase occurs which is accomplished by doubling of DNA.
—T/F 47. Eukaryotic cells are far larger and more complex than
the prokaryotic cells.
—T/F 48. The free-energy change for ATP hydrolysis is small
and negative.
—T/F 49. The antherozoid of Funaria is nonciliated, because it
is nonmotile.
—T/F 50. In sequential reactions of glycolysis, there occurs four
chemical transformations.
—T/F 51. In lysogenic cycle, the viral nucleic acid is
incorpo-rated into the host DNA.
—T/F 52. During photosynthesis, oxygen comes from water
was proved by Kamen and Ruben.
—T/F 53. The part of the embryo of grasses that lies next to the
endosperm is called coleoptile.
—T/F 54. Monotropa is an obligate saprophyte.
—T/F 55. The bivalents, during metaphase-I, become arranged
in the plane of the equator to form equatorial plate.
—T/F 56. In a hypogynous flower the ovary occupies the
highest position on the thalamus.
—T/F 57. Natural selection does not maintain favourable genes
within a population.
—T/F 58. Mycorrhiza is the symbiotic relationship between
roots of higher plants and fungi.
—T/F 59. Thetegmensofseedsdevelop from inner integument.
—T/F 60. Porphyrins are important part of chlorophylls and
cytochromes.
—T/F
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(Continued from Page 1075) 68. What are those movements in which whole of the plant body or the cell or cytoplasm moves from one place to another called ?
➠ Movements of locomotion 69. What is the arrangement of bundles in dicot
her-baceous stem ?
➠Bundles are arranged in a distinct ring that separates the cortex from the central pith
70. What is naturally occurring group of individuals of the same genotype called ?
➠ Biotype 71. What causes black necrosis of stem and root ?
➠Deficiency of boron 72. Which part of plant— Autumn crocens—is used for
the extraction of colchicine ?
➠ Root 73. What does dendrochronology determine ?
➠Age of tree by radiocarbon dating 74. What is called the protein part of an enzyme ?
➠ Apoenzyme 75. What does primary lysosome mean ?
➠Lysosomes containing inactive enzymes 76. What is Morchel commonly called ?
➠ Sponge mushroom 77. Who proposed the ‘Operon model’ of gene regulation
and organization in prokaryotes ?
➠ Jacob and Monad 78. What is the shape of chloroplast in Ulothrix ?
➠ Girdle-shaped 79. Why does plant’s life require a vascular system on
land ?
➠ Because plants must transport water and minerals 80. What is the name of most edible mushroom most
often seen on the tables of restaurants ?
➠ Agaricus compestris
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Physics
Q. Whyradiotransistorsdonot