DNA Structure and Replication Practice Questions
20 free DNA Structure and Replication practice questions for the USMLE Step 1, each with the correct answer and a detailed explanation. Open any question below, or take the full set as an interactive quiz.
Questions
20 questions
All DNA Structure and Replication questions
- Q1. Which model correctly describes how DNA replication conserves parental strands during duplication?
- Q2. Which enzyme is responsible for unwinding the DNA double helix at the replication fork by breaking hydrogen bonds between base pairs?
- Q3. Why must DNA replication be initiated with a primer rather than directly by DNA polymerase?
- Q4. What distinguishes leading-strand synthesis from lagging-strand synthesis during DNA replication?
- Q5. Which enzyme joins Okazaki fragments on the lagging strand to create a continuous DNA strand?
- Q6. Which of the following proteins stabilize single-stranded DNA during replication to prevent re-annealing or degradation?
- Q7. What is the role of topoisomerase (or DNA gyrase in prokaryotes) during DNA replication?
- Q8. Which DNA polymerase performs the bulk of leading-strand synthesis in prokaryotes during replication?
- Q9. Which of the following correctly describes the directionality of new DNA strand synthesis by DNA polymerase?
- Q10. Why are Okazaki fragments necessary on the lagging strand during DNA replication?
- Q11. Which component forms the “replisome” complex at the replication fork in prokaryotes?
- Q12. Which statement correctly describes the number of origins of replication in prokaryotic versus eukaryotic chromosomes?
- Q13. Which of the following polymerases is primarily responsible for lagging-strand elongation in eukaryotic cells?
- Q14. What problem at the ends of linear eukaryotic chromosomes is addressed by the enzyme telomerase during replication?
- Q15. What is the role of single-stranded DNA binding proteins (SSBs) during replication?
- Q16. During DNA replication, which enzyme replaces RNA primers on the lagging strand with DNA in prokaryotes?
- Q17. Which of the following is NOT required for formation of the replication fork during DNA replication?
- Q18. Which feature of DNA’s structure provides the chemical basis for the semiconservative replication mechanism?
- Q19. If a toxin specifically inhibited DNA primase, which process would be directly impaired during DNA replication?
- Q20. Which statement correctly describes how replication forks proceed on circular prokaryotic chromosomes?