GATE 2013 Microbiology Questions and Answers

gateQ.1 In 1976, Tonegawa’s experiment gave clue about gene rearrangement during differentiation of Bcells. The two different types of cells used in this experiment were (A) HeLa cells and fibrosarcoma cells
(B) embryonic cells and fibroblasts
(C) adult myeloma cells and HeLa cells
(D) embryonic cells and adult myeloma cells

Q.2 To which one of the following groups, the antibiotics kanamycin, streptomycin and gentamicin belong
(A) cephalosporins (B) macrolides
(C) aminoglycosides (D) quinolonesQ.3 Shine Dalgarno’s sequence present in mRNA binds to (A) 3’end of rRNA
(B) 5’end of rRNA
(C) 5’end of tRNA
(D) 3’end of tRNA

Q.4 Which one of the following transport mechanism is NOT employed by prokaryotes?(A) Passive diffusion (B) Group translocation
(C) Endocytosis (D) Active transport

Q.5 The most common indicator organism of faecal pollution in water is
(A) Clostridium botulinum (B) Bacillus subtilis
(C) Escherichia coli (D) Clostridium tetani
Q.6 The theoretical maximum number of ATP molecules produced from aerobic oxidation of glucose by eukaryotic cells is (A) 38 (B) 24 (C)12 (D) 8 Q.7 Which one of the following DO NOT use water as an electron source during photosynthesis?(A) Sulfate reducing bacteria
(B) Methanogenic bacteria
(C) Green and purple bacteria
(D) Nitrifying bacteria
Q.8If the radius of a spherical coccus is 0.8 µm, the value of volume surfacearea in µm-1 will be
(A) 7.45 (B) 4.05 (C) 3.75 (D) 0.85
Q.9 The enzyme that catalyzes the reduction of nitrogen to ammonia is
(A) nitrogenase (B) nitrate reductase (C) nitrite reductase (D)deaminase

Q.10 Chemostat is a continuous culture system in which sterile medium is fed into the culture vessel at the same rate as the spent medium is removed. If in a chemostat culture, the flow rate is 30 ml h-1and volume of the medium inside the vessel is 100 ml, the dilution rate in h-1is(A) 3.33 (B) 1.50 (C) 0.75 (D) 0.30
Q.11 In an experiment the structural genes lacZYAof lac operon were found to be constitutively expressed. The following explanations were given for the constitutive expression(P) absence of a functional repressor due to mutation in the repressor gene lacI
(Q) mutation in the operator that can no longer bind the repressor
(R) mutation in the lac A gene
Which of the following is CORRECT
(A) Only P (B) Only Q (C) Both P & Q (D) Only R

Q.12 Which one of the following is TRUE about siderophores in bacteria?(A) Siderophores are secreted only when soluble iron is available in the medium
(B) Siderophores form complex with ferrous ions in the medium
(C) Siderophores are the only route of iron uptake
(D) Siderophores form complex with ferric ions in the medium
 Q.13 In a population containing fast and slow growing bacteria, the slow growing bacteria can be enriched by supplementing the medium with (A) chloramphenicol (B) penicillin (C) penicillin & chloramphenicol (D) rifampin

Q.14 When the supply of tryptophan is plentiful, the tryptophan operon is repressed because the
(A) repressor protein-corepressor complex is bound at the operator
(B) repressor protein is synthesized in large quantity
(C) repressor-corepressor complex is not formed
(D) repressor becomes inactive and therefore has reduced specificity for the operator

Q.15 Match the scientists in Group I with their contributions in microbiology in Group II
GATE 2013 MicrobiologyQ.16 Match the infectious agents in Group I with the associated diseases in Group II
GATE 2013 Microbiology
Q.17 Match the microscopes in Group I with their working principles in Group II
GATE 2013 Microbiology
Q.18 In a phenol coefficient test for determining the efficacy of a disinfectant X, the maximum effective dilution for X and phenol was found to be 1/450 and 1/90, respectively. Calculate the phenol coefficient for X.
(A) 10.0 (B) 5.0 (C) 1.0 (D) 0.2

Q.19 How many electrons are accepted when sulfate acts as the terminal electron acceptor in bacteria such as Desulfovibrio?(A) 8 (B) 6 (C) 4 (D) 2

Q.20 A bacterial population increases from 103 cells to 109 cells in 10 h. Calculate the number of  generations per hour.
(A) 20 (B)10 (C)4 (D)2
Answers:
1.D ,2.C, 3.A, 4.C, 5.C, 6.A, 7.C, 8.C, 9.A, 10.D
11 C ,12.D, 13.B, 14.A, 15.B, 16.ALL, 17.B, 18.B, 19.A, 20.D

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