What is the function of primase? a. synthesis of the repetitive, short double-stranded DNA sequences required by DNA polymerase b. synthesis of a short RNA strand that is complementary to single-stranded DNA c. closing the gap at the 3′ end of DNA after excision repair d. removing primers and synthesizing a short section of DNA to replace them

Verified step by step guidance

1. Identify the role of primase in DNA replication: Primase is an enzyme involved in the replication of DNA.
2. Understand the function of primase: Primase synthesizes a short RNA primer at the 5' end of the DNA strand to provide a starting point for DNA polymerase, which requires a double-stranded region to initiate DNA synthesis.
3. Analyze the given options: Option b states that primase synthesizes a short RNA strand that is complementary to single-stranded DNA, which aligns with the function of providing a starting point for DNA polymerase.
4. Eliminate other options: Options a, c, and d describe functions related to DNA polymerase and DNA repair mechanisms, not the initial RNA primer synthesis by primase.
5. Select the correct answer: Based on the understanding of primase's role, the correct answer is b. synthesis of a short RNA strand that is complementary to single-stranded DNA.

Key Concepts

Primase Function

Primase is an enzyme that synthesizes short RNA primers during DNA replication. These primers provide a starting point for DNA polymerase, which cannot initiate synthesis without a pre-existing strand. The RNA primers are complementary to the single-stranded DNA template, allowing for accurate replication.

DNA Replication

DNA replication is the biological process of producing two identical replicas of DNA from one original DNA molecule. This process involves several key enzymes, including helicase, which unwinds the DNA, and DNA polymerase, which extends the new DNA strand. Primase plays a crucial role by laying down RNA primers to facilitate this process.

RNA vs. DNA

RNA (ribonucleic acid) and DNA (deoxyribonucleic acid) are both nucleic acids but differ in structure and function. RNA is typically single-stranded and contains ribose sugar, while DNA is double-stranded and contains deoxyribose sugar. The presence of uracil in RNA instead of thymine, which is found in DNA, is also a key distinction that affects their roles in cellular processes.