If all the cell in our body are replaced at some point in our life, why do we get old and die?

Question

If all the cell in our body are replaced at some point in our life, why do we get old and die?

In: Biology

Answer 1

The process of replacing our cells does not make a perfect copy.

Instead, every time our cells divide, things called telomeres get a little shorter each time. Eventually they get too short to work properly, leading to the effects of aging.