What is the role of DNA helicase during DNA replication?

• A. To add nucleotides to the growing DNA strand
• B. To join Okazaki fragments
• C. To synthesize new DNA strands
• D. To unwind the DNA double helix

Answer: (D)

Verified step by step guidance

1. Understand the process of DNA replication: DNA replication is the process by which a cell duplicates its DNA, creating two identical copies. This process is essential for cell division.
2. Identify the role of DNA helicase: DNA helicase is an enzyme that plays a crucial role in DNA replication by unwinding the DNA double helix.
3. Explain the unwinding process: DNA helicase breaks the hydrogen bonds between the complementary base pairs, separating the two strands of the DNA double helix. This creates two single strands that serve as templates for the synthesis of new DNA strands.
4. Differentiate from other enzymes: DNA polymerase is the enzyme responsible for adding nucleotides to the growing DNA strand, while DNA ligase joins Okazaki fragments on the lagging strand. DNA helicase specifically unwinds the DNA, which is a distinct and necessary step before these other processes can occur.
5. Summarize the importance: The unwinding of the DNA double helix by DNA helicase is a critical initial step in DNA replication, allowing the replication machinery access to the single-stranded DNA templates needed for synthesizing new DNA strands.