GRE Biology Mock Exam – Molecular Biology (50 MCQs)
Topic: DNA, RNA, Protein Synthesis
Time: 90 minutes | Ques ons: 50 MCQs | Max Marks: 50
DNA Replica on (Q1–Q10)
Q1. Which enzyme unwinds the DNA double helix at replica on forks?
a) Ligase
b) Helicase
c) Primase
d) Topoisomerase
Q2. Which enzyme relieves supercoiling ahead of the replica on fork?
a) Ligase
b) Topoisomerase
c) Helicase
d) Primase
Q3. The lagging strand is synthesized:
a) Con nuously toward replica on fork
b) Discon nuously away from fork
c) Con nuously away from fork
d) Discon nuously toward fork
Q4. Okazaki fragments are joined by:
a) Helicase
b) Ligase
c) DNA polymerase I
d) Primase
Q5. In prokaryotes, which enzyme removes RNA primers?
a) DNA polymerase I
b) DNA polymerase III
c) Ligase
d) Helicase
Q6. Telomerase is:
a) DNA helicase
b) DNA-dependent DNA polymerase
c) Reverse transcriptase
d) DNA ligase
Q7. In eukaryotes, replica on begins at:
a) Single origin
b) Mul ple origins
c) Centromeres only
d) Random sites
, Q8. The 5′ → 3′ exonuclease ac vity is unique to:
a) DNA polymerase I
b) DNA polymerase III
c) Ligase
d) Primase
Q9. In prokaryo c DNA replica on, clamp loader and sliding clamp are components of:
a) DNA polymerase I
b) DNA polymerase III holoenzyme
c) Helicase
d) Primase
Q10. Which base pair is most resistant to denatura on?
a) A–T
b) G–C
c) A–U
d) T–A
Transcrip on (Q11–Q20)
Q11. In prokaryotes, the -10 region of promoter is rich in:
a) G–C pairs
b) A–T pairs
c) U–A pairs
d) G–T pairs
Q12. Sigma factor is required for:
a) Chain elonga on
b) Promoter recogni on
c) Termina on
d) RNA processing
Q13. Which RNA polymerase transcribes rRNA genes (except 5S) in eukaryotes?
a) RNA Pol I
b) RNA Pol II
c) RNA Pol III
d) DNA Pol δ
Q14. TATA box is recognized by:
a) TBP (TATA-binding protein)
b) RNA Pol II directly
c) Sigma factor
d) Enhancer proteins
Q15. Which is NOT a eukaryo c transcrip on termina on signal?
a) Polyadenyla on sequence (AAUAAA)
b) Rho factor
c) CPSF cleavage factor
d) Poly(A) polymerase recruitment
Topic: DNA, RNA, Protein Synthesis
Time: 90 minutes | Ques ons: 50 MCQs | Max Marks: 50
DNA Replica on (Q1–Q10)
Q1. Which enzyme unwinds the DNA double helix at replica on forks?
a) Ligase
b) Helicase
c) Primase
d) Topoisomerase
Q2. Which enzyme relieves supercoiling ahead of the replica on fork?
a) Ligase
b) Topoisomerase
c) Helicase
d) Primase
Q3. The lagging strand is synthesized:
a) Con nuously toward replica on fork
b) Discon nuously away from fork
c) Con nuously away from fork
d) Discon nuously toward fork
Q4. Okazaki fragments are joined by:
a) Helicase
b) Ligase
c) DNA polymerase I
d) Primase
Q5. In prokaryotes, which enzyme removes RNA primers?
a) DNA polymerase I
b) DNA polymerase III
c) Ligase
d) Helicase
Q6. Telomerase is:
a) DNA helicase
b) DNA-dependent DNA polymerase
c) Reverse transcriptase
d) DNA ligase
Q7. In eukaryotes, replica on begins at:
a) Single origin
b) Mul ple origins
c) Centromeres only
d) Random sites
, Q8. The 5′ → 3′ exonuclease ac vity is unique to:
a) DNA polymerase I
b) DNA polymerase III
c) Ligase
d) Primase
Q9. In prokaryo c DNA replica on, clamp loader and sliding clamp are components of:
a) DNA polymerase I
b) DNA polymerase III holoenzyme
c) Helicase
d) Primase
Q10. Which base pair is most resistant to denatura on?
a) A–T
b) G–C
c) A–U
d) T–A
Transcrip on (Q11–Q20)
Q11. In prokaryotes, the -10 region of promoter is rich in:
a) G–C pairs
b) A–T pairs
c) U–A pairs
d) G–T pairs
Q12. Sigma factor is required for:
a) Chain elonga on
b) Promoter recogni on
c) Termina on
d) RNA processing
Q13. Which RNA polymerase transcribes rRNA genes (except 5S) in eukaryotes?
a) RNA Pol I
b) RNA Pol II
c) RNA Pol III
d) DNA Pol δ
Q14. TATA box is recognized by:
a) TBP (TATA-binding protein)
b) RNA Pol II directly
c) Sigma factor
d) Enhancer proteins
Q15. Which is NOT a eukaryo c transcrip on termina on signal?
a) Polyadenyla on sequence (AAUAAA)
b) Rho factor
c) CPSF cleavage factor
d) Poly(A) polymerase recruitment
