What enzyme is responsible for “unzipping” the DNA strand during replication? A. DNA helicase, B. DNA ligase, C. DNA polymerase, D. RNA primase.

Step 1: Define the Problem

Identify which enzyme is responsible for "unzipping" the DNA strand during replication.

Step 2: Break Down the Problem

• Understand the role of each enzyme listed:
  • DNA helicase: Unwinds the DNA double helix.
  • DNA ligase: Joins Okazaki fragments on the lagging strand.
  • DNA polymerase: Synthesizes new DNA strands.
  • RNA primase: Synthesizes RNA primers.

Step 3: Apply Relevant Concepts

• The "unzipping" of DNA refers to the separation of the two strands of the DNA double helix, which is necessary for replication to occur.

Step 4: Analysis, Verify and Summarize

• DNA helicase is the enzyme that unwinds and separates the double-stranded DNA, making it accessible for replication.

Final Answer

The enzyme responsible for "unzipping" the DNA strand during replication is A. DNA helicase.