Indian Institute of Science 2010 Ph.D Biology Banglore entrace - Question Paper
INDIAN INSTITUTE OF SCIENCE BANGALORE - 560012
ENTRANCE TEST FOR ADMISSIONS - 2010
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Program Entrance Paper Paper Code |
Research Biological Sciences |
Day & Date SUNDAY, 25 APRIL 2010
Time
9.00 A.M. TO 12.00 NOON
GENER INSTRUCTIONS
1. This question paper consists of 100 multiple choices questions and carries a total of 100 marks, one mark for each question.
2. Answers to all questions should be marked in the OMR sheet provided.
3. For each question darken (fill) the appropriate bubble on the OMR sheet to indicate your answer.
4. Use only HB pencils to darken the bubbleslanswers
5. Darken only one bubble per question. If you mark more than one bubble to answer a question, it will be evaluated as incorrect
6. If you wish to change your answer, please erase the existing mark completely before filling in the other bubble
7. There is no negative marking for wrong answers.
8. Candidates are required to fill in the required fields on the answers sheet attached.
BIOLOGICAL SCIENCES
1. The post office is involved in processing, packaging and distribution.
Because of these functions, it could be used as an analogy for which cellular organelle?
(A) Plasma membrane (3) Nucleolus
(C) Golgi apparatus
(D) Mitochondria
2. Which one of the following proteins is involved in promoter recognition in eukaryotes?
(A) TFIIF
(B) TFIIB
(C) TFIID (P) TFIIE
3. The enzyme responsible for conversion of a negatively supercoiled DNA into a relaxed circular DNA is
(A) DNA gyrase
(B) DNA Topoisomerasel
(C) DNA Topoisomerase LI
(D) DNA helicase
4. In which of the secondary structures, two residues well separated (more than 10 residues) in the amino acid sequence can be proximal in the threedimensional structure?
(A) a-helix
(B) p-sheet
(D) |3-tum
5. Smal and Xmal are isoschizomers. A circular DNA has two Smal and one Xmal sites. How many fragments will be generated by digestion with Xmal?
(B) 2
(C) 3
(D) 4
6. The cone cl way to write ihe scientific name of garden pea is
(A) pisum sati vum
(B) Pisum Sativum
(C) Pisum sativum
(D) PISUM sativum
7. Replication of the full length chromosome of E. coli
(A) takes exactly as long as it takes E. coli to divide
(B) takes longer than it takes E. coli to divide
(C) takes lesser time than it takes E. coli to divide
(D) depends on the use of ISN or MN nitrogen source in the medium.
8. Which of the following does NOT employ nuclear receptors to mediate its signaling?
(A) Epinephrine
(B) Estrogen
(C) Progesterone
(D) Testosterone
9. 32P has a half life of 14 days. After 3 months what would be the residual radioactivity of 1 milli Curie of ATP labeled with 32P?
(A) 62.5 micro Curie
(B) 6.25 micro Curie
(C) 15.5 micro Curie
(D) 1.55 micro Curie
10. Penicillin inhibits the synthesis of bacterial cell wall by binding to
(A) trans-peptidase
(B) alanine racemase
(C) N-acetyl galactosamine
(D) N-acetyl muramic acid
11. Which compound can serve as a direct acceptor of an additional amino group derived from amino acid catabolism?
(A) Glutamine
(B) Fumarate
(C) Alpha-ketoglutarate
(D) Glycerol
12. The effective resistance when two resistors of 1 and 4 ohms are connected in parallel is
(A) 5.0 ohms
(B) 3. Oohins
(C) 2.5 ohms
(D) 0.8 ohms
! 3. What is the smallest distance between two closely spaced points which can be resolved by light microscopy?
(A) 20 nm
(B) 200 nm
(C) 2 micron
(D) 2 ran
14. The speed of an action potential through a nerve fibre can be increased by
(A) reducing the diameter of the nerve fibre
(B) increasing the insulation of the nerve Fibre
(C) increasing the concentraiion of the sodium and potassium ions
(D) decreasing the length of the nerve fibre
15. Which neuron is found in the peripheral nervous system?
(A) Purkinje neuron
(B) Granule cell neuron
(C) Motor neuron
(D) Pyramidal neuron
16. Which of the following does NOT occur during the dark reaction of photosynthesis?
(A) Utilization of NADPH
(B) Utilization of ATP
(C) Reduction of oxygen to produce water
(D) Synthesis of glucose
17. Akinetopsia is an acquired disorder which results in impaired ability to
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perceive | |
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(A) |
color |
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(B) |
motion |
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(C) |
form |
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(D) |
letters |
18. If the absolute temperature doubles, the velocity of molecules in a gas increases by a faclor of
(B) 4
(C) V2
(D) V3
19. Antigenic determinants generated by the conformation of amino acids present in the variable regions of immunoglobins are
(A) allotypic
(B) idiotypic
(C) anti-idiotypic
(D) heterotypic
20. Chorionic gonadotropin hormone, synthesized in the placenta, plays an important role in the establishment and maintenance of pregnancy in
(A) cows
(B) pigs
(C) rodents
(D) humans
21. In the eye, which cells are responsible for visual detection in low light conditions?
(A) Rods
(b) Cones
(C) ON cells
(D) Bipolar cells
22. Whai is the sequence of cell cycle progression in eukaryotic cells?
(A) Gl to G2 to S to M
(B) Gl to M to G2 to S
(C) Gl to Sto M to G2
(D) Gl to S to G2 to M
23. If all the 8 cysteine residues in a protein take part in making disulfide bonds, then the possible number of ways the four S-S bonds can be formed is
(A) 8C2
(C) 7 x 5 x 3 x 1 (0) 4x3 x2x 1
24. Albinism is a condition thal results from the lack of normal pigmentaiion. Individuals possessing Lwo recessive alleles (aa) are albino. Similarly, attached earlobes result from two recessive alleles (ee). In a family, the husband is an albino wiih atiached earlobes and the wife is pigmented with non-attached earlobes. All their 20 children are pigmented with non-attached earlobes. What is the genotype of the mother?
(A) aaee
(B) aaEE
(C) AaEe
(D) AAEE
25. Which of the following DNA elements will cause stable integration into plant genome?
(A) T-DNA & Ds elements
(B) Mu element & Ac/ Ds elements
(C) T-DNA & Mu element
(D) Ds elements & Ac/ Ds elements
26. Which protein has the least number of amide groups in the polypeptide backbone?
(A) Myosin
(B) Silk
(C) Collagen
(D) Keraiin
27. A plasmid of 2200 bp size was isolated fran E. coli and found to have a linking number (L*) of 190. The negative value of the writhe (Wr) for this plasmid would
(A) be more if the DNA adopted an A-form structure than if it did a B-form structure
(B) be less if the DNA adopted an A-form structure than if it did a B-form structure
(C) be independent of the A-form or the B-form structures of the DNA
(D) vary only if the DNA in the plasmid adopted a Z-form structure
28. A recessive allele t is responsible for a condition called distonia. A man who has this condition marries a woman who doesn't have distonia. One of their four children suffers from this disorder. What are the possible genotypes of the man and woman?
(A) The father is Tt; the mother is TT
(B) The father is tt; the mother is TT
(C) Both parents are tt
(D) The father is tt; the mother is Tt
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29. Which one of the followinghas least solubility in water?
(A) Lysozyme
(B) Collagenase
(C) DNA polymerase
(D) Rhodopsin
30. The structure equivalent to the frogs Spemann's organizer in chicks is
(A) Hensens node
(B) Notochord
(C) Anterior visceral endodenn
(D) Ventral mesoderm
31. Which pair of amino acids represents the weakest interaction between their side chains?
(A) Ser... Leu
(B) Asn ... Thr
(C) Tyr ... Trp
(D) Lys ... Phe
32. A double reciprocal plot for an enzymatic reaction with a ping pong Bi Bi mechanism looks similar to the plot obtained for
(A) Competitive inhibition
(B) Uncompetitive inhibition
(C) Non competitive inhibition
(D) Mixed non competitive inhibition
33. Aspirin, used as a common analgesic, antipyretic and anti-mflammatoiy agent, inhibits the synthesis of which one of the following?
(A) Arachidonic acid
(B) Prostaglandins
(C) Glucocorticoids
(D) Histamine
34. Which of the following proteins are expressed on the surface of helper T cells but not on cytotoxic T cells?
(A) CD2
(B) CD3
(C) CD4
(D) CD8
36. Bacteria can be made partially diploid in a stable manner by
(A) mating with an Hr strain
(B) mating with a strain thar carries an F' factor containing the gene of interest
(C) phage mediated transduction
(D) transformation with a linear DNA fragment that carries rhe gene of
interest
37. Heart beat is regulated by the
(A) vagus nerve
(B) trigeminal nerve
(C) glossopharyngeal nerve
(D) trochlear nerve
38. Which one of the following statements is NOT applicable to integral membrane proteins?
(A) they have compact three-dimensional structure
(B) they can be without a-helical region
(C) polar side chains are exposed to the surroundings
(D) the main chain amide and carbonyl groups are engaged in hydrogen
bonding
39. At low temperature the sterol content of membrane increases in cultured cells in order to
(A) increase membrane fluidity
(B) increase the production of lipid intracellular signalling molecules
(C) stabilize membrane proteins
(D) increase permeabi I ity to water
40. If a motor nerve has a conduction velocity of 70 m/s, how long will it take an action potential to reach a muscle 0.75 m away from the spinal cord?
(A)
(C) 14 ms
(D) 1.4 ms
41. Point mutations in the Ras proiooncogeneare associated with sanecancers. These point mutations lead to
(A) loss of function
(B) gain of function
(C) no change in function
(D) premature termination
42. You have discovered a compound that inhibits fumarase. How many moles of ATP would you expect to be generated from one mole of acetyl CoA in the presence of inhibitor?
(A) 5
(B) 6
(C) 6.5
(D) 7.5
43. In a family, both husband and wife have blood group 'A'. The first child bom to them was found to have O1 blood group. What is the probability that their next child will have blood group 'A'?
(A) 0.5
(B) 0.75
(C) 0
(D) 0.25
44. Which calcium binding proiein regulates the smooth muscle contraction?
(A) Troponin-C
(B) Calmodulin
(C) Calcineurin
(D) Calpain
45. Which compound cannot cross the inner membrane of mitochondria?
(A) ATP
(B) Pyrophosphate
(C) Pyruvate
(D) Acetyl CoA
46. Which of the following antigen-antibody interactions does NOT involve precipitation reaction?
(A) Radial immunodiffusion
(B) Ouchterlony
(C) ELISA
(D) Immunoelectrophoresis
47. Cytokinesis in a plant cell is characterized by
(A) the equal division of homologous chromosomes
(B) pinching off of the cell membrane to divide the cell
(C) the formation of a cell plate in the cytoplasm
(D) the movement of the chromosomes from the metaphase plate
48. The following data refer to the hydrolysis of various tripeptides into their N-terminal amino acids and C-terminal dipeptides catalysed by intestinal aminopeptidase at pH 7.0 and 37C.
substrate_(s' )_Km (mM)
L-Pro-Gly-Gly 385 : T71
L-Leu-Gly-Gly 190 0.55
L-Ala-Gly-Gly 365 1.4
L-Ala-Ala-Ala 298 0.52
Which of the following substrates would be hydrolysed most rapidly in the early stages of reaction if the enzyme was added to equimolar concentration of the substrates individually?
(A) L-Pro-Gly-Gly
(B) L-Leu-Gly-Gly
(C) L-Ala-Gly-Gly
(D) L-Ala-Ala-Ala
49. The biological activity of anterior pituitary glycoprotein hormones such as FSH and LH depends on their native structure, whichis
(A) Homodimer
(B) Ileterodimer
(C) Monomer
(D) Tetrarner
50. An rRNA sample was degraded into its constituent nucleotides. The absorbance of this sample at 260 nm would
(A) decrease if ihe degradation was effected by alkaline digesiion but increase if the same was effected by a ribonuclease
(B) increase if the degradation was effected by alkaline digestion but decrease if the same was effected by a ribonuclease
(C) remain the same irrespective of the use of chemicals or enzymes
(D) increase irrespective of the use of chemicals or enzymes
51. In which cells of the leaf does photosynthesis occur?
(A) Mesophyll cells
(B) Bundle sheath cells
(C) Guard cells
(D) Lower epidermal cells
52. A cell free extract of E.coU contains 24 mg protein/ml. 20 jil of this extract in a standard incubation volume of 0.1 ml catalyzed the incorporation of l4C-glucose from L4C glucose-1-phosphate into glycogen at a rate of 1.6 nmole / ndn. The velocity of the reaction in terms of (i) fimoles/min and
(ii) ]nmoles/mg protein/mm are:
(A) 1.6 10'2 and 3.33 * 10'2
(B) 1.6 x 10'1 and 3.33 * 10*
(C) 1.6 x I0'3 and 3.33 * 10
(D) 1.6 x 10" and 3.33 x 10"1
53. The end-to-end distance of a 10 amino acid alpha-helix is -15.2 A. If these ten residues were in a fully extended conformation (beta-strand) the approximate end-to-end distance would be
(A) 15.2A
(B) 5A
(C) 32A
(D) 70A
54. Superantigens
(A) are exceptionally large antigen molecules
(B) elicit a strong antibody response
(C) attach non-specifically to B cell receptors
(D) activate a large number of T cells
55. Which enzyme causes the release of pyrophosphate from ATP?
(A) Glycogen phosphorylase
(B) RNA polymerase
(C) ATPase
(D) Aspartate transcarbamylase
56. In which activated form does inorganic sulphate enter metabolic pathways?
(A) Sulpho Epid
(B) Methionine
(C) Thiourea .
(D) Phosphoadenosine phosphosulphate
57. The composition oforal polio' vaccination given worldwide is
(A) attenuated neurovirulant Poliovirus
(B) heat killed Poliovirus sabin type
(C) combination of types 1-3 of heat killed poliovirus strains
(D) Crivalent preparation of live attenuated poliovirus types 1, 2 and 3
58. For the half reactions shown below, which one of ihe following statements is true?
E' (V)
01 + 2H+ + 2e' O H20 0.815
02 + 2H+ + 2e <-> H2O2 0.295 Cytochrome b (Fe3+) + e- <-> Cytochrome b (Fe2+) 0.077 NAD+ + H+ + 2e <-> NADH -0.315
(A) Oxygen is more easily reduced than NAD+
(B) NAD+ has a lower tendency to get oxidized than oxygen
(C) cytochrome b (Fe2*) is more easily oxidized than NADH
(D) cytochrome b (Fe3+) is less easily reduced than 02
59. Chloroform is more miscible with water than carbon tetrachloride because chloroform has a
(A) lower dipole moment than carbon tetrachloride
(B) lower dielectric constant than carbon tetrachloride
(C) higher dipole moment than carbon tetrachloride
(D) higher order of symmetry than carbon tetrachloride
60. Which one of the following covalent modifications occurs both in DNA as well as histones and contributes to repression of transcription or gene silencing in eukaryotic cells?
(A) Acelylation
(B) Phosphorylation
(C) Methylation
(D) Sumoy l ation
61. The direction of migration of the tripeptide Lys-Lys-Lys in an electric field ai pH = 3 and at pH = 10 is
(A) Cathode and Cathode respectively
(B) Caihode and Anode respectively
(C) Anode and Cathode respectively
(D) Anode and Anode respectively
62. Which phytohormones are overproduced in plant tumors caused by Agrobacterium?
(A) Ethylene and auxin
(B) Auxin and cytokinin
(C) Cytokinin and Gibberllin
(D) Gibbereliin and auxin
63. If the intracellular concentration of NaCl is 1%, then which solution is hypotonic to the cell?
(A) 0.1 N
(B) 0.2 N
(C) 0.3 N
(D) 0.4 N
64. Which of the following statements about DNA replication is NOT common to the synthesis of both leading and lagging strands?
(A) RNA primer is synthesized
(B) DNA polymerase III synthesizes DNA
(C) Nucleoside monophosphates are added in a 5' to 3' direction along the growing DNA chain
(D) DNA ligase repeatedly joins the ends of DNA along the growing strand
65. Which phytohormone induces seed dormancy?
(A) Gibberellin
(B) Abscisic acid
(C) Auxin (d) Ethylene
66. If the pre- and post-synaptic cells are incubated in Ca2l"-free medium, then
(A) synaptic transmission would take place at a faster time scale
(B) membrane depolarization of the pre-synaptic cell would not take place
(D) membrane depolarization of the post-synaptic cell would not take place
67. The native structure of a protein, whose formation from its denatured state is favoured at a temperature below T = AH/ AS. For what values of AH and AS will this condiiion be satisfied?
(A) AH is -vc and AS is +ve
(B) AH is -ve and AS is-ve
(C) AH is +ve and AS is +ve
(D) AH is +ve and AS is -ve
68. Upon replication of a covalently closed circular genome (such as the E. coli genome), the daughter chromosomes are obtained as catenated circles. These catenated circles are resolved prior to cell division by
(A) the nicking activity of DNA polymerase
(C) reverse activity of a DNA ligase followed by its forward activity
(D) topoisomerase I
69. Parkinson's disease is characterised by cell dealh in the
(A) substantia nigra
(B) motor cortex
(C) frontal cortex
(D) spinal cord.
70. Which post translational modification is used to anchor a protein on the membrane?
(A) Phosphorylation
(B) Prenylation
(C) Acetylation
(D) Methylaiion
71. The genome of the Avian flu virus (H5N1) that causes bird flu consists of
(A) Single stranded DNA
(B) Positive strand RNA
(C) Negative strand RNA
(D) Double stranded DNA
72. The amino acid carboxyprolinehas three ionizable groups with the following properties
pKa
2.0
10.5
3.8
Group a - carboxyl a - amino y - carboxyl
The isoelectric point for this amino acid is
(A) 2.9
(B) 6.25
(C) 7.15
(D) 5.4
73. Which one of the following statements is CORRECT?
(A) Phytochromes perceive red/far red light and cryptochromes perceive blue light
(B) Phytochromes perceive blue light and cryptochromes perceive red/far red
(C) Both phytochromes and cryptochomes can perceive the entire visible spectrum
(D) Phytochromes and cryptochromes absorb W light and infra red light, respectively
(A) They are enveloped
(B) Their RN A is spliced f C) They contain LTRs
(D) They integrate into host DNA
75. In a stretch of DNA, 10 % of guanines form non-Watson and Crick base pairing with adenine. If the segment contains 29% guanine, the amount of thymine would be
(B) 20%
(C) 29%
(D) 18%
76. Telomerase is composed of
(A) only protein
(B) only RNA
(C) Protein and RNA
(D) Protein and DNA
77. Four stainless steel rods of radius R and length L are packed tight in a square coniainer. The volume of the unoccupied space at the periphery (edge) is
(A) twice that of the unoccupied space at the center
(B) three times that of the unoccupied space at the center
(C) equal to that of the unoccupied space at the center
(D) four times that o f the unoccupied space at the ccnter
78. Under a given renaturing condition E. coli DNA reassociates with a Cot 1/2 of 4.0 and an unknown DNA sample with a Cotj/2 of 283. The complexity of this unknown DNA will be
(A) 4.2 X 106 bp (3) 6 X I05 bp
(C) 3.0 X 10s bp
(D) 340 bp
79. Which mutation cannot occur in a tRNA encoding gene?
(A)
Deletion Transition Trans version Nonsense mutaiion
(C)
80. Bacteriophage M13 was prepared from an E. coli culture grown in a medium containing N as the sole nitrogen source. It was used to infect a fresh culture of E. coli at an m.o.i. of about 1 and grown in a medium containing nN as the sole nitrogen source. The replicative form of DNA of M13 phage was prepared after 4 generations of E. coli growth and analyzed by CsCl density gradient ultracentrifiigation. The separated ,SN and containing DNA will be seen as
(A) a single band
(B) two bands
(C) three bands
(D) four bands
81. Which amino acid is phosphorylated in bacterial proteins?
(A) Arginine
(B) Cysteine
(C) Lysine
(D) Histidine
82. The phrase horizontal gene transfer means that
(A) genes can diffuse within the cytoplasm
(B) the DNA molecule can move horizontally but not vertically
(C) genes can pass between individuals in the absence of sexual reproduction
(D) whenever a gene passes from P to Q, another gene must pass from Q to P
83. Two children have a neurological disorder. When cells derived from these two children were fused and cultured, the resultant cells displayed normal metabolism. However, cells from either patient exhibited abnormal metabolism when cultured separately. These results indicate that
(A) the disorder is caused by mutations in the same gene
(B) the disorder is caused by mutations in non-allelic genes
(C) symptoms of the disorder cannot be observed at ihe cellular level
(D) the disorder cannot be due to loss of the same enzyme activity
84. DNA polymerase V in E. coli is crucial for the template and primer dependent polymerization of dNTPs for
the high fidelity replication of the parent chromosome DNA synthesis during nucleotide excision repair DNA synthesis during error prone replication DNA synthesis during mismatch repair
(A)
(C)
85. The Shine-Dalgamo sequence facilitates binding of eubacterial mRNAs to the
(A) 30S ribosomal subunit via the 16S rRNA
(B) 50S ribosomal subunit via the 23S rRNA
(C) 30S ribosomal subunit via the 5S rRNA
(D) SOS ribosomal subunit via the 5S rRNA
86. Three vertices of a parallelogram have the following coordinates:
(-4, 4), (3, 6)and (7, 2). What are the coordinates of the fourth one?
87. In human oocytes, the interval between the first and second meiotic divisions is typically a few
(A) seconds
(B) hours
(C) days
(D) years
88. Gonadotropin releasing hormone and Gonadoiropins are produced by
(A) hypothalamus only
(B) hypothalamus and anterior pituitary respectively
(C) anterior pituitary and hypothalamus respectively
(D) anterior pituitary cnly
89. The storage disease associated with excess spingomyelin is callcd
(A) Niemann Pick
(B) Sandhoff
(C) Tay Sachs
(D) Krabbes
90. The interaction of information coming from the two eyes for depth perception first occurs in which of the following structures devoted to vision?
(A) Retina
(B) Thalamus
(C) Primary visual cortex
(D) Parietal cortex
91. An equilateral triangle is inscribed in a circle of radius r. What is the length of the side of the triangle?
(A) r
(B) 2r
(C) 3 r
(D) (V3/2) r
92. If a valine residue is buried in a protein structure, which one of the substitutions is likely to be least disruptive lo the three-dimensional structure?
(A) Val He
(B) Val -> Giy
(C) Val -> Thr
(D) Val Phe
93. In a peptide unit C a refers to the central carbon atom in an amino acid and C refers to the carbon in the carbonyl group. Which covatent bond is the mosi difficult to rotate in Ihe peptide unit?
(B) C-N
(C) N-H
(D) N-Ca
94. Induced pluripotent stem cells (iPS) are usually generated from
(A) 4-8 cell stage of an embryo
(B) inner cell mass of blastocysts
(C) adult somatic cclls
(D) placenta
95. Within the mitochondrion, the proton gradient develops across the
(A) outer membrane
(B) inner membrane
(C) intermembrane space
(D) matrix
96. A cellular protein has higher affinity for inositol triphosphate compared-to phosphatidyl inositol 4,5-bisphosphate (PIP2). Where would you expect this protein to be localized when phopholipase C beta enzyme (which hydrolyses PIP2) is activated?
(A) On the plasma membrane
(C) On the ER
(D) On the Golgi membrane
97. A mutant G0 protein with increased GTPase activity would
(A) not bind to GTP
(B) not bind to GDP
(C) show increased signalling
(D) show decreased signalling
98. A protein segment consists of a stretch of 10 residues that adopt ana-helical secondary structure conformation. What is the maximum number of hydrogen bonds that can stabilize this a - helix?
(A) 4
(B) 5
(C) 6
(D) 7
99. Salt bridges formed in proteins involve
(A) Sulfur atoms in cysteine side chains
(B) Metal ions such as Na and K
(C) Oppositely charged side chains
(D) Proximal aromatic and aliphatic side chains
100. The theory of evolution by natural selection states that
(A) selection results in generating variations
(B) selection and variations are independent
(C) evolution is independent of variation
(D) evolution is a rapid process
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