MCQ Questions on Molecular Biology
1. The function of β subunit of polymerase is
(a) Template binding
(b) Catalytic binding
(c) Promoter binding
(d) Cation binding
Answer
Answer: (b) Catalytic binding
2. Which of the σ factors is heat stable?
(a) σ 54
(b) σ 70
(c) σ 28
(d) σ 32
Answer
Answer: (d) σ 32
3. The mRNA codon of valine is
(a) GUC
(b) UGG
(c) CCA
(d) TTG
Answer
Answer: (a) GUC
4. True replication of DNA is due to
(a) Phosphate backbone
(b) Hydrogen bonding
(c) Complementary base pairing rule
(d) None
Answer
Answer: (c) Complementary base pairing rule
5. Which of the following statements is not applicable to viruses?
(a) The virus replicates in a bacterial host
(b) The protein coat of a virus does not enter the host cell
(c) The genetic material is DNA or RNA
(d) Virus replicate autonomously in the absence of host
Answer
Answer: (d) Virus replicate autonomously in the absence of host
6. Mode of DNA replication is
(a) Conservative and bidirectional
(b) Semiconservative and unidirectional
(c) Semiconservative and bidirectional
(d) Conservative and unidirectional
Answer
Answer: (c) Semiconservative and bidirectional
7. Which enzyme is used to join nicks in the DNA strand?
(a) Primase
(b) DNA polymerase
(c) DNA ligase
(d) Endonuclease
Answer
Answer: (c) DNA ligase
8. Which enzyme is used in the unwinding of DNA?
(a) Ligase
(b) Topoisomerase
(c) Helicase
(d) Exonuclease
Answer
Answer: (c) Helicase
9. Which of the following processes does not occur in prokaryotes?
(a) Transcription
(b) Splicing
(c) Translation
(d) Replication
Answer
Answer: (b) Splicing
10. cDNA is synthesised from RNA by the enzyme
(a) DNA polymerase
(b) DNA synthetase
(c) DNA convertase
(d) Reverse transcriptase
Answer
Answer: (d) Reverse transcriptase
11. Which of the following base-pairing rule is correct?
(a) Adenine with guanine and thymine with cytosine
(b) DNA base pairing is non-specific
(c) Adenine with cytosine and guanine with thymine
(d) Adenine with thymine and guanine with cytosine
Answer
Answer: (d) Adenine with thymine and guanine with cytosine
12. DNA synthesis can be measured by estimating the incorporation of radiolabelled
(a) Thymine
(b) Guanine
(c) Cytosine
(d) Adenine
Answer
Answer: (a) Thymine
13. How many RNA polymerases are present in a bacterial system?
(a) 4
(b) 2
(c) 1
(d) 3
Answer
Answer: (c) 1
14. During DNA replication the synthesis of the leading strand of DNA results in fragments known as
(a) Okazaki fragments
(b) Satellite segments
(c) Kornberg segment
(d) Double-helix segment
Answer
Answer: (a) Okazaki fragments
15. Short strands of ——- primer are used in DNA replication.
(a) DNA
(b) RNA
(c) Histone
(d) Protein
Answer
Answer: (b) RNA