What is the function of primase in DNA replication?

• A. It unwinds the DNA double helix to allow replication to occur.
• B. It synthesizes a short RNA primer to initiate DNA synthesis.
• C. It joins Okazaki fragments on the lagging strand.
• D. It adds nucleotides to the growing DNA strand in a 5' to 3' direction.

Answer: (B)

Verified step by step guidance

1. Understand the role of primase in DNA replication: Primase is an enzyme that plays a crucial role in the initiation of DNA synthesis.
2. Recognize the need for a primer: DNA polymerases, which synthesize DNA, cannot start the synthesis process on their own. They require a short RNA primer to begin adding nucleotides.
3. Learn how primase synthesizes the primer: Primase synthesizes a short RNA primer complementary to the DNA template strand, providing a starting point for DNA polymerase.
4. Identify the location of primer synthesis: Primase synthesizes the RNA primer at the origin of replication and at the start of each Okazaki fragment on the lagging strand.
5. Understand the importance of the primer: The RNA primer synthesized by primase is essential for DNA polymerase to begin DNA synthesis, ensuring accurate replication of the DNA molecule.