DNA Repair and Gene Regulation - Gene Expression and Its Regulation, and DNA Repair - Life Sciences Previous Year Questions

1

2007 · Life Sciences · Gene Expression and Its Regulation, and DNA Repair · DNA Repair and Gene Regulation

Life Sciences (XL) 2007

Match the DNA binding motifs mentioned in Column A with the proteins given in Column B.

A	B
(P) Zinc finger	(1) c-jun
(Q) Leucine zipper	(2) Growth hormone receptor
(R) Helix-turn-helix motif	(3) Glucocorticoid receptor
	(4) Histone H1
	(5) Lambda repressor

A

P-4, Q-5, R-1

B

P-2, Q-5, R-4

C

P-2, Q-1, R-5

D

P-3, Q-1, R-5

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2

2007 · Life Sciences · Gene Expression and Its Regulation, and DNA Repair · DNA Repair and Gene Regulation

Life Sciences (XL) 2007

Si RNA(s) interfere at

A

transcriptional level

B

post-transcriptional level

C

DNA replication level

D

translational level

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3

2008 · Life Sciences · Gene Expression and Its Regulation, and DNA Repair · DNA Repair and Gene Regulation

Life Sciences (XL) 2008

Which of the following statements are true with respect to a special complex called ‘dicer’?
(P) It consists of deoxyribonuclease and DNA fragments
(Q) It consists of ribonuclease and RNA fragments
(R) It is involved in gene silencing
(S) It triggers apoptosis

A

P, R

B

Q, R

C

P, S

D

Q, S

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4

2009 · Life Sciences · Gene Expression and Its Regulation, and DNA Repair · DNA Repair and Gene Regulation

Life Sciences (XL) 2009

When E.coli is grown in glucose and lactose, the lac operon is not expressed. This is because glucose interferes with

A

removal of repressor.

B

binding of activator.

C

removal of repressor and binding of activator.

D

removal of activator.

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5

2009 · Life Sciences · Gene Expression and Its Regulation, and DNA Repair · DNA Repair and Gene Regulation

Life Sciences (XL) 2009

Determine the correctness or otherwise of the following Assertion (a) and Reason (r) :
Assertion (a) : IPTG (Isopropylthiogalactoside) is a gratuitous inducer of lac operon.
Reason (r) : IPTG is an efficient inducer, but not a substrate of lac operon.

A

Both (a) and (r) are true and (r) is the correct reason for (a).

B

Both (a) and (r) are true but (r) is not the correct reason for (a).

C

is true but (r) is false.

D

is false but (r) is true.

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6

2009 · Life Sciences · Gene Expression and Its Regulation, and DNA Repair · DNA Repair and Gene Regulation

Life Sciences (XL) 2009

RecA is a protein involved in

A

Recombinational repair

B

Mismatch repair

C

Nucleotide excision repair

D

Base excision repair

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7

2010 · Life Sciences · Gene Expression and Its Regulation, and DNA Repair · DNA Repair and Gene Regulation

Life Sciences (XL) 2010

In tryptophan operon, tryptophan acts as

A

Repressor

B

Activator

C

Co-repressor

D

Co-activator

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8

2010 · Life Sciences · Gene Expression and Its Regulation, and DNA Repair · DNA Repair and Gene Regulation

Life Sciences (XL) 2010

In a lacOᶜ lacZ⁺ / lacO⁺ lacZ⁻ partial diploid, of the two lacZ enzymes, only the mutant enzyme (lacZ⁻) is synthesized constitutively. This observation shows that lacOᶜ mutation is

A

trans-dominant

B

trans-recessive

C

cis-dominant

D

cis-recessive

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9

2010 · Life Sciences · Gene Expression and Its Regulation, and DNA Repair · DNA Repair and Gene Regulation

Life Sciences (XL) 2010

Which one of the following events occurs in prokaryotes but NOT in eukaryotes?

A

Protein phosphorylation

B

RNA polymerase and promoter interaction

C

Control of transcription by attenuation

D

Formation of Okazaki fragments

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10

2011 · Life Sciences · Gene Expression and Its Regulation, and DNA Repair · DNA Repair and Gene Regulation

Life Sciences (XL) 2011

Catabolite repression allows cells to save energy by

A

inactivating catabolic enzymes

B

inhibiting synthesis of total RNA

C

regulating expression of genes required for utilization of less-efficient metabolites

D

inhibiting translation of mRNAs encoding catabolic enzymes

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11

2012 · Life Sciences · Gene Expression and Its Regulation, and DNA Repair · DNA Repair and Gene Regulation

Life Sciences (XL) 2012

An E.coli mutant constitutive for the lac operon was mated with a wild type strain. The merodiploid thus obtained was inducible by lactose. This observation indicates that the original mutation is

A

dominant

B

trans-dominant

C

recessive

D

cis-dominant

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12

2013 · Life Sciences · Gene Expression and Its Regulation, and DNA Repair · DNA Repair and Gene Regulation

Life Sciences (XL) 2013

In an experiment the structural genes lacZYA of 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 lacAgene
Which of the following is CORRECT

A

Only P

B

Only Q

C

Both P & Q

D

Only R

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13

2013 · Life Sciences · Gene Expression and Its Regulation, and DNA Repair · DNA Repair and Gene Regulation

Life Sciences (XL) 2013

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

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14

2013 · Life Sciences · Gene Expression and Its Regulation, and DNA Repair · DNA Repair and Gene Regulation

Life Sciences (XL) 2013

Among the following molecular process-biological effect pairs, identify the mismatched pair.

A

Histone deacetylation – activation of gene expression

B

Protein phosphorylation – signal transduction

C

DNA methylation – sex-specific control of gene expression

D

Proteolytic cleavage – activation of signaling by peptide hormones

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15

2014 · Life Sciences · Gene Expression and Its Regulation, and DNA Repair · DNA Repair and Gene Regulation

Life Sciences (XL) 2014

Identify the CORRECT answer
RNA interference (RNAi)
P. is an event of post transcriptional gene silencing
Q. works through RNA induced silencing complex

A

P only

B

Q only

C

Both P and Q

D

neither P nor Q

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16

2015 · Life Sciences · Gene Expression and Its Regulation, and DNA Repair · DNA Repair and Gene Regulation

Life Sciences (XL) 2015

The working volume (in liter) of a chemostat with 0.1 h^-1 dilution rate and 100 ml/h feed flow rate is ______

A

i

B

iii

C

ii

D

iv

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17

2015 · Life Sciences · Gene Expression and Its Regulation, and DNA Repair · DNA Repair and Gene Regulation

Life Sciences (XL) 2015

An E. coli strain is grown initially on glucose as the sole carbon source. Upon complete consumption of glucose following 12 h of growth, lactose is added as the sole carbon source and the strain is further grown for 12 h. Assuming that the E. coli strain has a functional wild type lac operon, which one of the following profiles is the most ACCURATE representation of β-galactosidase (β-gal) expression (in arbitrary units)?

A

i

B

iii

C

ii

D

iv

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18

2016 · Life Sciences · Gene Expression and Its Regulation, and DNA Repair · DNA Repair and Gene Regulation

Life Sciences (XL) 2016

Which ONE of the following mechanisms is used to coordinate the expression of multiple, related genes in eukaryotic cells?

A

Environmental signals enter the cell and bind directly to promoters.

B

Genes share a common intragenic sequence, and allow several activators to turn on their transcription, regardless of location.

C

Genes are organized into large operons, allowing them to be transcribed as a single unit.

D

Genes are organized into clusters, with local chromatin structures influencing the expression of all the clustered genes at once.

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19

2017 · Life Sciences · Gene Expression and Its Regulation, and DNA Repair · DNA Repair and Gene Regulation

Life Sciences (XL) 2017

Match the enzymes given in Group I with the events from Group II.

Group I
(P) UvrABC endonuclease
(Q) Reverse transcriptase
(R) AP endonuclease
(S) ATP sulfurylase

Group II
(I) Retrovirus replication
(II) Base excision repair
(III) Nucleotide excision repair
(IV) Pyrosequencing

A

P-II, Q-I, R-IV, S-III

B

P-III, Q-I, R-II, S-IV

C

P-IV, Q-III, R-I, S-II

D

P-II, Q-I, R-III, S-IV

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20

2020 · Life Sciences · Gene Expression and Its Regulation, and DNA Repair · DNA Repair and Gene Regulation

Life Sciences (XL) 2020

Which one of the following conditions favors maximum expression of lac operon genes in E. coli?

A

Glucose-low, lactose-low, cAMP-high

B

Glucose-high, lactose-low, cAMP-high

C

Glucose-low, lactose-high, cAMP-high

D

Glucose-high, lactose-high, cAMP-low

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