Final answer:
Primase is indeed necessary on both strands, sliding clamps are reloaded for each Okazaki fragment, telomerase is not a DNA polymerase, and primase does not have a proofreading function.
Step-by-step explanation:
Let's evaluate each statement regarding DNA replication:
1. Primase is needed to initiate DNA replication on both the leading strand and the lagging strand. This statement is true. Primase synthesizes a short RNA primer that provides a 3'-OH group which is essential for DNA polymerase to start adding DNA nucleotides.
2. The sliding clamp is loaded once on each DNA strand, where it remains associated until replication is complete. This statement is false. The sliding clamp must be reloaded at the beginning of each new Okazaki fragment on the lagging strand, as each fragment requires a new primer and is synthesized discontinuously.
3. Telomerase is a DNA polymerase that carries its own RNA molecule to use as a primer at the end of the lagging strand. This statement is false. Telomerase is not a DNA polymerase; it is an enzyme that extends the telomeres of chromosomes to prevent their shortening, using its RNA component as a template for adding DNA repeats.
4. Primase requires a proofreading function that ensures there are no errors in the RNA primers used for DNA replication. This statement is false. Primase does not have a proofreading function; the short RNA primers it synthesizes do not require such a high-fidelity mechanism because they are eventually removed and replaced by DNA nucleotides.
Therefore, the correct options for the statements are:
• A: True
• B: False (Sliding clamps are reloaded for each Okazaki fragment)
• C: False (Telomerase is not a DNA polymerase)
• D: False (Primase does not proofread RNA primers)