Replication, Transcription and Translation - 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 · Replication, Transcription and Translation

Life Sciences (XL) 2007

A nonsense mutation in the gene encoding protein X leading to the synthesis of a truncated protein results in a slow growing strain. Mutagenesis of this strain towards the isolation of extragonice suppressors led to the isolation of a strain which grew normally and synthesized the full-length protein X. The extragonice suppressor is likely to be a gene coding for

A

rRNA

B

RNA polymerase

C

tRNA

D

Ribosomal protein

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2

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

Life Sciences (XL) 2007

Which of the DNA polymerases listed below is primarily responsible for the de novo synthesis of new DNA strands?

A

DNA polymerase I

B

DNA polymerase II

C

DNA polymerase III

D

DNA polymerase IV

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3

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

Life Sciences (XL) 2007

Which of the following proteins binds tightly to DNA in the chromatin structure and influences eukaryotic DNA replication ?

A

Histones

B

Lamins

C

Vimentin

D

Proteasome

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4

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

Life Sciences (XL) 2007

During DNA replication significant proportion of newly synthesized DNA in the lagging strand exists as small Okazaki fragments. The sizes of these units in bacteria are approximately

A

100 nucleotides

B

1000 nucleotides

C

100 base pairs

D

1000 base pairs

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5

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

Life Sciences (XL) 2008

Transcription initiation sites can be determined by

A

Footprinting

B

Northern blotting

C

Primer extension

D

Nick translation

Check answer

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6

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

Life Sciences (XL) 2008

The mol.wt. of 45s pre-rRNA is

A

2x10⁶

B

4.5x10⁵

C

4.5x10⁶

D

3.9x10⁷

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7

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

Life Sciences (XL) 2008

The number of pre-rRNA genes per genome is approximately

A

10

B

100

C

1000

D

10,000

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8

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

Life Sciences (XL) 2008

The 'Kornberg's enzyme' is now known as

A

DNA polymerase III

B

DNA polymerase II

C

DNA polymerase I

D

DNA ligase

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9

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

Life Sciences (XL) 2009

Which of the following statements are INCORRECT ?
P. The frequency of recombination is a measure of linkage between genes on the same chromosome.
Q. DNA polymerase I is the true DNA replicase in E. coli.
R. The conserved element closest to the transcription initiation site is called the CAAT box.
S. The introns in the nuclear pre-mRNAs are excised by spliceosomes.

A

P, Q

B

Q, R

C

P, R

D

P, S

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10

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

Life Sciences (XL) 2009

Which combination of the following statements with regard to gene expression is true ?
1. Heteronuclear RNA represents contiguous segment of genomic DNA.
2. UTRs are part of heteronuclear RNA but not of mRNA.
3. UTRs are part of exons.
4. Translation start codon MUST be in the first exon.

A

1 – true, 2 – false, 3 – false, 4 –false

B

1 – true, 2 – false, 3 – true, 4 – false

C

1 – true, 2 – true, 3 – false, 4 – true

D

1 – false, 2 – true, 3 – true, 4 – true

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11

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

Life Sciences (XL) 2011

The synthesis of an immunoglobulin in either a secretory or membrane bound form is governed by

A

allelic exclusion

B

class switching

C

differential RNA processing

D

affinity maturation

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12

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

Life Sciences (XL) 2011

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

A

20 min

B

40 min

C

10 min

D

18 min

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13

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

Life Sciences (XL) 2013

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

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14

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

Life Sciences (XL) 2014

A human gene has only three exons (I, II and III in the given order). Total RNA was isolated from cultured human kidney cells and reverse transcribed. The resultant cDNA was used as a template in a PCR reaction containing a forward primer specific to Exon I and a reverse primer specific to Exon III. When the PCR product was analyzed by gel electrophoresis, two bands were observed of sizes 2.5 kb and 1 kb. However, when Northern blotting was performed with the same total RNA using a radiolabeled probe specific to Exon II, only one band was observed. Based on these observations, which one of the following statements is FALSE?

A

Northern blotting with a probe specific to Exon III will show two bands.

B

The gene codes for two mRNA splice variants.

C

If the forward primer were specific to Exon II, two bands will be observed.

D

The Exon II is 1.5 kb in size.

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15

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

Life Sciences (XL) 2014

The length of a coding region in an mRNA is 897 bases. How many amino acids will be there in the polypeptide synthesized using this mRNA?

A

297

B

298

C

299

D

897

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16

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

Life Sciences (XL) 2014

The TATA box is found in the vicinity of the transcription start site. The role of this box is to

A

serve as a ribosome recruitment site

B

serve as RNA polymerase binding site

C

provide 3-D structural integrity to a DNA molecule

D

act as a terminator sequence

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17

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

Life Sciences (XL) 2014

Which ONE of the following processes does NOT occur in prokaryotic gene expression, but occurs in eukaryotic gene expression?

A

Transcription of mRNA, rRNA, and rRNA

B

Binding of RNA polymerase to the promoter

C

Addition of a poly-A tail to the 3' end and the 5' capping of an mRNA

D

Translation begins as soon as transcription is initiated

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18

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

Life Sciences (XL) 2015

Defect in poly-A tail formation in eukaryotic mRNA leads to

A

Increased translation of the resulting mRNA

B

Decreased translation of the resulting mRNA

C

Premature transcription termination

D

Decreased mRNA stability

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19

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

Life Sciences (XL) 2016

Heterologous expression of green fluorescent protein is possible because the genetic code is

A

universal

B

triplet

C

degenerate

D

non-overlapping

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20

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

Life Sciences (XL) 2016

E. coli ribonuclease contains 124 amino acids. The number of nucleotides present in the gene encoding the protein is __________.

Check answer

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