What is the role of DNA Topoisomerase (DNA Gyrase) during DNA replication?
Answer and explanation
Correct answer: B. Relieves positive supercoiling and torsional strain ahead of replication fork
- Step 1: As helicase unwinds the DNA duplex, twisting tension builds up ahead of the advancing fork. Step 2. Topoisomerase transiently cuts one or both DNA strands to relieve supercoiling strain and reseals them. Answer: Relieves positive supercoiling and torsional strain ahead of replication fork. Why not the others: Helicase breaks hydrogen bonds; primase synthesizes RNA primers; exonuclease degrades primers.
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