GATE BT Molecular Biology PYQs & Answers — Page 5

Questions 41–50 of 50. Imported answers require independent review unless marked reviewed.

Determine the correctness or otherwise of the following Assertion [a] and the Reason [r]

Assertion: The association constant in water for the G-C base pair is three times lower than that for the A-T base pair.

Reason: There are three hydrogen bonds in the G-C base pair and two in the A-T base pair.

Your answerChoose one option.

Both [a] and [r] are true and [r] is the correct reason for [a]

[a] is false but [r] is true

Both [a] and [r] are false

Both [a] and [r] are true and [r] is not the correct reason for [a]

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An analysis of DNA-protein interactions was carried out using all DNA-protein complexes in the protein data bank (PDB). The frequency distribution of four amino acid residues, represented as P, Q, R and S, occurring in non-covalent interactions between the protein and DNA backbone is shown below.

Which one of the following is correct?

Your answerChoose one option.

P-Lys, Q-Arg, R-Gln, S-Glu

P-Ile, Q-Glu, R-Lys, S-Arg

P-Asn, Q-Asp, R-Arg, S-Lys

P-His, Q-Glu, R-Gln, S-Lys

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5′ capping of mRNA transcripts in eukaryotes involves the following events: P. Addition of GMP on the 5′ end Q. Removal of γ-phosphate of the triphosphate on first base at the 5′ end R. 5′-5′ linkage between GMP and the first base at 5′ end S. Addition of methyl group to N7 position of guanine

Which one of the following is the correct sequence of events?

Your answerChoose one option.

P, Q, R, S

P, R, Q, S

Q, P, R, S

Q, P, S, R

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If the nucleotide composition (%) of a viral genome is A = 10, U = 20, C = 40, and G = 30, which one of the following is this genome?

Your answerChoose one option.

Double stranded RNA

Single stranded RNA

Single stranded DNA

Double stranded DNA

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During protein synthesis, tRNAs are NOT involved in

Your answerChoose one option.

charging

initiation

elongation

termination

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The transcription factor X binds a 10 base pair DNA stretch. In the DNA of an organism, X was found to bind at 20 distinct sites. An analysis of these 20 binding sites showed the following distribution:

Base	1	2	3	4	5	6	7	8	9	10
A	11	0	0	0	16	2	4	0	4	3
T	3	0	19	0	1	3	4	20	2	4
G	4	20	0	0	2	4	6	0	12	2
C	2	0	1	20	1	11	6	0	2	11

What is the consensus sequence for the binding site of X?

Your answerChoose one option.

NGTCNNTNNN

AGTCACNTGC

CACCTANCTG

ANNNACGNGC

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A bacterium has a genome of size 6 million base pairs. If the average rate of DNA synthesis is 1000 base pairs/second, the time taken (in minutes) for replication of the genome will be _____.

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At the transcription start site of a gene, any of the four nucleotides can occur with equal probability

. The Shannon Entropy S, given by

, for this start site is __________.

Given data:

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A recombinant protein is to be expressed under the control of the lac promoter and operator in a strain of E. coli having the genotype lac⁺ crp⁺. Even in the absence of inducer IPTG, low levels of expression of the recombinant protein are seen (leak expression). Which one of the following should be done to minimize such leak expression?

Your answerChoose one option.

Addition of lactose to the medium

Removal of all glucose from the medium

Addition of excess glucose to the medium

Addition of allo-lactose to the medium

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A DNA strand of length 25 nm wraps diametrically around the circumference of a spherical histone-octamer once. The radius (nm) of the histone-octamer is ________. Given data:

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GATE BT Molecular Biology PYQs

Question 31

Question 37

Question 40

Question 8

Question 17

Question 23

Question 24

Question 25

Question 42

Question 52