Which of the following statements about DNA synthesis is true?

• A. DNA synthesis occurs in the 3' to 5' direction.
• B. DNA polymerase can initiate synthesis without a primer.
• C. DNA synthesis requires RNA primers to initiate the process.
• D. DNA synthesis occurs only during the G1 phase of the cell cycle.

Answer: (C)

Verified step by step guidance

1. Understand the directionality of DNA synthesis: DNA synthesis occurs in the 5' to 3' direction, not 3' to 5'. This is because DNA polymerase can only add nucleotides to the 3' end of a growing DNA strand.
2. Recognize the role of primers in DNA synthesis: DNA polymerase cannot initiate synthesis on its own. It requires a short RNA primer to provide a starting point for DNA synthesis.
3. Identify the phase of the cell cycle where DNA synthesis occurs: DNA synthesis takes place during the S phase (Synthesis phase) of the cell cycle, not the G1 phase.
4. Evaluate the given statements: The statement 'DNA synthesis requires RNA primers to initiate the process' is true because RNA primers are necessary for DNA polymerase to begin adding nucleotides.
5. Conclude by confirming the correct statement: Based on the understanding of DNA synthesis directionality, the role of primers, and the cell cycle phase, the correct statement is that DNA synthesis requires RNA primers to initiate the process.