Which enzyme builds the new DNA strand by adding nucleotides during DNA replication?

• A. DNA polymerase
• B. Ligase
• C. Primase
• D. Helicase

Answer: (A)

Verified step by step guidance

1. Understand the role of each enzyme listed in the options during DNA replication.
2. DNA polymerase is the enzyme responsible for adding nucleotides to the growing DNA strand, synthesizing the new strand in the 5' to 3' direction.
3. Ligase is an enzyme that joins Okazaki fragments on the lagging strand, sealing nicks in the sugar-phosphate backbone.
4. Primase synthesizes a short RNA primer that provides a starting point for DNA polymerase to begin DNA synthesis.
5. Helicase unwinds the DNA double helix, separating the two strands to allow replication to occur.