In the overview of DNA replication, what is the primary role of helicase?

• A. It relieves torsional strain ahead of the replication fork by cutting and rejoining DNA strands.
• B. It unwinds the DNA double helix by breaking hydrogen bonds between complementary base pairs, separating the two strands.
• C. It synthesizes new DNA strands by adding nucleotides to the 3′ end of a growing strand.
• D. It seals nicks in the sugar-phosphate backbone to join Okazaki fragments into a continuous strand.

Answer: (B)