CLEP Biology

Answer: A - In DNA replication, the enzyme that unwinds DNA is called helicase. Helicase unwinds the double helix structure so that other enzymes that are important for replication have access to the DNA strands.

Key Takeaway: DNA replication is the process by which all living organisms copy their DNA. After helicase unwinds the helix, DNA polymerase uses the separate strands as templates to synthesize two new complimentary strands according to the Watson-Crick model of base pairing. After proofreading enzymes check to make sure that the DNA was properly synthesized, other enzymes seal the DNA into its double helix structure, resulting in the creation of two new DNA molecules from the two template strands.