When a cell's DNA is damaged and cannot be repaired, it can undergo apoptosis or enter senescence.

“if a cell's fate is such that it can't repair its DNA that's sort of when it has this bifurcated pathway of going down the pathway of apoptosis which means for the listener that it has a programmed form of cell death so it basically kills itself in a programmatic structured way or it goes down this pathway that you've described which is senescence effectively saying I will no longer do anything I'm still alive but I don't grow anymore I don't replicate I don't reproduce anymore my DNA is dysfunctional”