CSIR UGC NET JRF Life sciences - Molecular Biology Questions (Unit 3- Fundamental Process)

UNIT-3. Fundamental Processes (DNA replication, DNA repair and recombination, RNA synthesis and processing, Protein synthesis and processing, Control of gene expression at transcription and translation level)

1. Which one of the following chemicals is a DNA intercalator? (CSIR Life sciences, Dec 2015)

1. 5-Bromouracil

2. Ethyl methane sulfonate

3. Acridine orange

4. UV

Ans: 3. Acridine orange

2. An antibiotic that resembles the 3’end of a charged tRNA molecule is: (CSIR Life sciences, Dec 2015)

1. Streptomycin

2. Sparsomycin

3. Puromycin

4. Tetracycline

Ans: 3. Puromycin

3.α-Amanitin is a fungal toxin which inhibits eukaryotic RNA polymerases. The three eukaryotic RNA polymerases show differential sensitivity to this toxin. Which one of the following order (higher to lower) is correct in respect of sensitivity towards α - amanitin? (CSIR Life sciences, Dec 2015)

1. RNA POL III > RNA POL II > RNA POL I

2. RNA POL II > RNA POL III > RNA POL I

3. RNA POL I > RNA POL III > RNA POL II

4. RNA POL II > RNA POL I > RNA POL III

Ans: 2. RNA POL II > RNA POL III > RNA POL I

4. In eukaryotic replication, helicase loading occurs at all replicators during (CSIR Life sciences, Dec 2015)

1. G0 phase

2. G1 phase

3. S phase

4. G2 phase

Ans: 2. G1 phase

5.Error-free repair of double strand breaks in DNA is accomplished by 

(CSIR Life sciences, June 2016)

1. non-homologous end-joining.

2. base excision repair.

3. homologous recombination.

4. mismatch repair.

Ans: 3. homologous recombination.

6. RNA interference is mediated by both siRNA and miRNA. Which one of the following statement about them is NOT true? (CSIR Life sciences, June 2016)

1. Both siRNA and miRNA are processed by DICER.

2. Both siRNA and miRNA usually guide silencing of the same genetic loci from

which they originate.

3. miRNA is a natural molecule while siRNA is either natural or a synthetic one.

4. miRNA, but not siRNA is processed by Drosha

Ans: 2. Both siRNA and miRNA usually guide silencing of the same genetic loci from which they originate.

7. Which of the following are NOT transcribed by RNA polymerase II? (CSIR Life sciences, dec 2016)

1. miRNA and some snRNA

2. miRNA and snoRNA

3. mRNA and snoRNA

4. tRNA and 5S rRNA

8 . RNA editing, a post-transcriptional process, is achieved with the help of guide RNA (gRNA).Which one of the following statements about the process is NOT true? (CSIR Life sciences, dec 2016)

1. g-RNA dependent RNA editing happens in the kinetoplast DNA

2. g-RNA is involved in chemical modification of t-RNA

3. This process involves insertion or deletion of uridines

4. Sequences edited once may be re-edited using a second g-RNA

Ans: 2. g-RNA is involved in chemical modification of t-RNA

9. Telomerase, a RNA-protein complex which completes the replication of telomeres during DNA synthesis, is a specialized  (CSIR Life sciences dec 2016)

1. RNA dependent DNA polymerase

2. DNA dependent DNA polymerase

3. DNA dependent RNA polymerase

4. RNA dependent RNA polymerase

Ans: 1. RNA dependent DNA polymerase

10. Consider a short double-stranded linear DNA molecule of 10 complete turns with 10.5bp/turn. The ends of the DNA molecule are sealed together to make a relaxed circle. This relaxed circle will have a linking number of (CSIR Life sciences dec 2016)

1. 105

2. 20.5

3. 10.0

4. 10.5

Ans: 3. 10.0