DNA Structure and Replication · USMLE Step 1

Which of the following is NOT required for formation of the replication fork during DNA replication?

  1. DNA helicase
  2. DNA ligase
  3. Single-strand binding proteins (SSBs)
  4. Topoisomerase
Show answer and explanation

Correct answer: DNA ligase

DNA ligase is used later to join Okazaki fragments; it is not required for formation of the replication fork itself, which needs helicase to unwind DNA, SSB to stabilize strands, and topoisomerase to relieve torsional stress.

Difficulty: Medium Question 17 of 20

Practice all 20 DNA Structure and Replication questions

Keep practicing

More DNA Structure and Replication questions