DNA Structure and Replication · USMLE Step 1

Which component forms the “replisome” complex at the replication fork in prokaryotes?

  1. Helicase + primase + DNA Pol III holoenzyme
  2. DNA Pol I + ligase + topoisomerase + SSB
  3. SSB + RNA polymerase + helicase + ligase
  4. Ligase + primase + topoisomerase + SSB
Show answer and explanation

Correct answer: Helicase + primase + DNA Pol III holoenzyme

The replisome in prokaryotes comprises helicase, primase, and the DNA Pol III holoenzyme working together at each replication fork to coordinate unwinding, primer synthesis, and DNA elongation.

Difficulty: Medium Question 11 of 20

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