Why is the DNA damage checkpoint in the G1 phase important in cell cycle regulation?

• A. It ensures that damaged DNA is repaired before the cell enters S phase.
• B. It accelerates the cell cycle to promote rapid cell division.
• C. It prevents the cell from undergoing apoptosis.
• D. It allows the cell to bypass the S phase and directly enter mitosis.

Answer: (A)

Verified step by step guidance

1. Understand the cell cycle: The cell cycle consists of several phases, including G1, S, G2, and M. The G1 phase is the first gap phase where the cell grows and prepares for DNA replication.
2. Recognize the role of checkpoints: Checkpoints are control mechanisms that ensure the cell cycle progresses correctly. The G1 checkpoint is crucial for assessing DNA integrity before replication.
3. Identify the importance of DNA repair: The G1 checkpoint ensures that any DNA damage is repaired before the cell enters the S phase, where DNA replication occurs. This prevents the propagation of damaged DNA.
4. Consider the consequences of bypassing the checkpoint: If the G1 checkpoint is not properly functioning, cells may replicate damaged DNA, leading to mutations and potentially cancerous growth.
5. Clarify misconceptions: The G1 checkpoint does not accelerate the cell cycle, prevent apoptosis, or allow bypassing the S phase. Its primary function is to ensure DNA integrity before replication.