End Test Now
Quinolones inhibit bacterial growth by targeting
DNA replication
RNA polymerase
mRNA translation
active transport of nutrients into the cell
To select for spontaneously arising histidine auxotrophs in a population, you would use a medium containing
Histidine and penicillin
Histidine and lysozyme
Penicillin but no histidine
Lysozyme but no histidine
Which one of the following statements is NOT associated with contributions of Louis Pasteur?
Anthrax is caused by anthrax bacillus
Bacteria causing food spoilage come from air
The disease causing organism must be isolated in pure culture
Bacteria cause the wine disease
The active transport of solute in the cell is characterized by
its uptake along the concentration gradient utilizing energy
requirement of a carrier to support transport along the concentration gradient
chemical modification of the solute during its uptake
its uptake against the concentration gradient
Catabolite repression allows cells to save energy by
inactivating catabolic enzymes
inhibiting synthesis of total RNA /
regulating expression of genes required for utilization of less-efficient metabolites
inhibiting translation of mRNAs encoding catabolic enzymes
A newly emerged variant of Influenza virus can be selectively propagated from the mixed population by addition of
Gangcyclovir
Tamiflu
interferon gamma
Neutralizing antibody
The synthesis of an immunoglobulin in either a secretory or membrane bound form is governed by
allelic exclusion
class switching
differential RNA processing
affinity maturation
The cis-trans test can determine whether a gene codes for
an activator or a repressor
an RNA or a protein
a protein with the same or different amino acids
a diffusible or non-diffusible product
Which of the following are expected to be the abundant inhabitants of a nitrate and sulfate rich soil naturally depleted for oxygen?
Pseudomonas and Azotobacter
Pseudomonas and Desulfovibrio
Azotobacter and Thiobacillus
Nitrosomonas and Nitrobacter
Which one of the following immersion oils would you use to get the best resolution in a light microscope (with 100X objective)?
an oil with refractive index of 1.6
an oil with refractive index of 1.S
an oil with refractive index of 1.4
Four Hfr strains of E. coli were generated from the same p+ strain. The Hfr strains donated markers in the following orderStrain1: DQWMT; Strain 2: AXPTM; Strain 3: BNCAX; Strain 4: BDQWMThe order of the markers in the original p+ strain is
DQWMTPXACNB
AXPTMDQWBNC
BNCAXPTMDQW
BDQWMNCAXPT
Which one of the following forms of the same DNA molecule would bind maximum ethidium bromide?
Negatively supercoiled
Covalently closed relaxed circle
Linear
Positively supercoiled
An actively growing culture of E. coli divides in about 20 min. Under laboratory conditions, time taken to replicate the entire genome of this bacterium would be about
20 min
40 min
10 min
18 min
Which of the statements about Corynebacterium diphtheriae biology is NOT CORRECT?
All strains of C. diphtheria are producers of diphtheria toxin
Diphtheria toxin production can be minimized by high concentration of iron in the medium
Diphtheria toxin inhibits protein synthesis
Diphtheria toxin is an A-B toxin secreted as a polypeptide of 62 kDa
Match the names of investigators in Group 1 with their contributions in Group 2
P-S ,Q-3 ,R-4,S-1
P-S,Q-3 ,R-1 ,S-2
P-4,Q-3 ,R-1 ,S-S
P-3, Q-2,R-1 ,S-4
During replication of the E. coli chromosome, Okazaki fragments are produced from
only one of the strands of the circular genome
both the strands of the circular genome
one of the strands in one generation and the other strand in the next generation
both the strands of the circular genome provided that the heavy nitrogen (15N) is present in the medium
A new isolate of a facultative anaerobe utilizes either oxygen or pyruvate as terminal electron acceptor. This bacterium was grown either anaerobically with glucose as sole carbon source; or aerobically with lactose as the sole carbon source. Net increase in ATP production (per mole of the carbon source) during the aerobic growth would be
2-fold
4-fold
19-fold
38-fold
Based on their properties, match the “Genera” in Group 1 with those in Group 2
P-4, Q-1, R-2, S-3
P-4, Q-1, R-3, S-2
P-2, Q-4, R-1, S-3
P-1, Q-4,R-2, S-3
An actively growing culture (20 ml) of E. coli (l x 105 per ml) was mixed with a total of 100 T4 phage particles, grown further for 40 min and mixed with a few drops of chloroform. Under the conditions used, the generation time of E. coli is 30 min, the infection cycle of phage T4 is 20 min, and the burst size is 100. Assuming that each infection was a successful one, how many plaque forming units would you expect at the end of the experiment?
104
103
105
106
Match the pair of organisms in Group 1 with their characteristic interactions in Group 2
P-2,Q-4,R-3, S-1
P-2,Q-3,R-4, S-1
P-4,Q-2,R-3, S-1
P-2,Q-4,R-1, S-3
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