The scenario describes a cell that contains DNA damage and has twice the amount of DNA expected for a cell of its type, which indicates some form of improper DNA replication or damage that could potentially affect normal cell division.
In the context of the cell cycle checkpoints:
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G1 Checkpoint: This checkpoint assesses whether the cell is ready for DNA synthesis and to enter S phase. It checks for DNA integrity and the cell's overall health.
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G2 Checkpoint: This checkpoint checks for DNA damage after replication has occurred (during the G2 phase) and before the cell enters mitosis (M phase). This is where the cell would check if there are any unresolved issues from DNA replication.
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M Checkpoint: Also known as the spindle assembly checkpoint, it ensures that all chromosomes are properly attached to the spindle apparatus before proceeding with mitosis.
Given that the cell in question has DNA damage and also possesses an abnormal amount of DNA (twice that of a normal cell), it is most likely that the cell would trigger apoptosis during the G2 checkpoint, where it evaluates DNA integrity after replication but before mitosis.
Therefore, the correct answer is:
B. G2 checkpoint
1 answer