MCQOPTIONS
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MCQOPTIONS
This section includes 17 Mcqs, each offering curated multiple-choice questions to sharpen your Microbiology knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
In , which enzyme synthesizes the RNA primer for Okazaki fragments? |
| A. | DnaA |
| B. | DnaC |
| C. | DnaG |
| D. | all of these |
| Answer» D. all of these | |
| 2. |
Which of the following statements on replication in is correct? |
| A. | It occurs in a unidirectional manner |
| B. | It occurs in bidirectional manner |
| C. | Always uses T7 DNA polymerase when infected by T7 phage |
| D. | Occurs only when λ phase has infected |
| Answer» C. Always uses T7 DNA polymerase when infected by T7 phage | |
| 3. |
Both strands of DNA serve as templates concurrently in |
| A. | replication |
| B. | excision repair |
| C. | mismatch repair |
| D. | none of these |
| Answer» B. excision repair | |
| 4. |
The enzyme that catalyzes the synthesis of DNA is called |
| A. | DNA polymerase |
| B. | DNA gyrase |
| C. | DNA ligase |
| D. | helicase |
| Answer» B. DNA gyrase | |
| 5. |
Which of the following possesses both 5'-3' and 3'-5' exonuclease activity? |
| A. | Kornberg enzyme |
| B. | DNA polymerase III |
| C. | Taq DNA polymerase |
| D. | None of these |
| Answer» B. DNA polymerase III | |
| 6. |
Proofreading activity to maintain the fidelity of DNA synthesis |
| A. | occurs after the synthesis has been completed |
| B. | is a function of the 3'-5' exonuclease activity of the DNA polymerases |
| C. | requires the presence of an enzyme separate from the DNA polymerases |
| D. | occurs in prokaryotes but not eukaryotes |
| Answer» C. requires the presence of an enzyme separate from the DNA polymerases | |
| 7. |
Which of the following repairs nicked DNA by forming a phosphodiester bond between adjacent nucleotides? |
| A. | Helicase |
| B. | DNA gyrase |
| C. | Topoisomerases |
| D. | DNA ligase |
| Answer» E. | |
| 8. |
During which of the following process a new copy of a DNA molecule is precisely synthesized? |
| A. | Trasformation |
| B. | Transcription |
| C. | Translation |
| D. | Replication |
| Answer» E. | |
| 9. |
Which of the following statements on replication in E.coli is correct? |
| A. | It occurs in a unidirectional manner |
| B. | It occurs in bidirectional manner |
| C. | Always uses T7 DNA polymerase when infected by T7 phage |
| D. | Occurs only when phase has infected |
| E. | <i>E. coli</i> |
| Answer» C. Always uses T7 DNA polymerase when infected by T7 phage | |
| 10. |
The replication of chromosomes by eukaryotes occurs in a relatively short period of time because |
| A. | the eukaryotes have more amount of DNA for replication |
| B. | the eukaryotic replication machinery is 1000 times faster than the prokaryotes |
| C. | each chromosome contains multiple replicons |
| D. | eukaryotic DNA is always single stranded |
| Answer» D. eukaryotic DNA is always single stranded | |
| 11. |
In E.coli, which enzyme synthesizes the RNA primer for Okazaki fragments? |
| A. | DnaA |
| B. | DnaC |
| C. | DnaG |
| D. | all of these |
| Answer» D. all of these | |
| 12. |
DNA gyrase is inhibited by |
| A. | tetracycline |
| B. | nalidixic acid |
| C. | both (a) and (b) |
| D. | cephalosporin |
| Answer» C. both (a) and (b) | |
| 13. |
DNA replication rates in prokaryotes are approximately of the order of |
| A. | 10 bases per second |
| B. | 1,00 bases per second |
| C. | 1,000 bases per second |
| D. | 10,000 bases per second |
| Answer» D. 10,000 bases per second | |
| 14. |
The synthesis of DNA by DNA polymerase occurs in the |
| A. | 3' to 5' direction |
| B. | 5' to 5' direction |
| C. | 5' to 3' direction |
| D. | 3' to 3' direction |
| Answer» D. 3' to 3' direction | |
| 15. |
Which of the following enzymes unwind short stretches of DNA helix immediately ahead of a replication fork? |
| A. | DNA polymerases |
| B. | Helicases |
| C. | Single-stranded binding proteins |
| D. | Topoisomerases |
| Answer» C. Single-stranded binding proteins | |
| 16. |
Which of the following lacks 3'-5' exonuclease activity? |
| A. | Short fragment of DNA polymerase I |
| B. | Taq DNA polymerase |
| C. | T4 DNA ligase |
| D. | All of the above |
| Answer» E. | |
| 17. |
During DNA replication in prokaryotes, synthesis begins on the circular chromosome |
| A. | always at the same place |
| B. | at any stretch of DNA that is high in AT pairs |
| C. | randomly on the chromosome |
| D. | at the promoter |
| Answer» B. at any stretch of DNA that is high in AT pairs | |