Imagine that a cell with a loss of function mutation in the G2/M checkpoint (in other words, the checkpoint is broken) is in G2 and has DNA damage. What is likely to happen to that cell?

Question

a. it will never pass the checkpoint

b. it will pass the checkpoint once, but then it will stop progressing through the cell cycle

c. It will pass the checkpoint and then accumulate additional mutations that affect other checkpoints.

Answer 1

The G2/M checkpoint is inhibitory -- it only allows entrance into mitosis if 1) all the DNA is copied and 2) errors of replication are corrected. If this checkpoint is mutated and loses its function, it no longer can halt a cell with known mutations enter to mitosis. So, the overall effect would be the daughter cells would carry this initial mutation, as well as any others from replication, and pass those on further into all descendant cells.