What enzyme unzips DNA by breaking hydrogen bonds between the two strands?

What enzyme unzips DNA by breaking hydrogen bonds between the two strands?

• A. Helicase
• B. Topoisomerase
• C. SSB proteins
• D. DNA polymerase

Answer: (A)

Unwinding the double helix to expose each strand is essential for DNA replication, and the enzyme that does this is DNA helicase. It uses energy from ATP to disrupt the hydrogen bonds between base pairs, effectively separating the two strands and creating a replication fork. Once the strands are separated, other proteins can stabilize the exposed single strands and allow DNA polymerases to synthesize new DNA. Topoisomerase helps relieve the twisting tension that results from unwinding, SSB proteins stabilize the single strands to prevent reannealing, and DNA polymerase builds the new DNA strands but cannot unwind the helix on its own. The focus here is on helicase’s role in breaking the hydrogen bonds to unzip the DNA.

Unwinding the double helix to expose each strand is essential for DNA replication, and the enzyme that does this is DNA helicase. It uses energy from ATP to disrupt the hydrogen bonds between base pairs, effectively separating the two strands and creating a replication fork. Once the strands are separated, other proteins can stabilize the exposed single strands and allow DNA polymerases to synthesize new DNA. Topoisomerase helps relieve the twisting tension that results from unwinding, SSB proteins stabilize the single strands to prevent reannealing, and DNA polymerase builds the new DNA strands but cannot unwind the helix on its own. The focus here is on helicase’s role in breaking the hydrogen bonds to unzip the DNA.