Human DNA Replication

bullet1 Life Cycle

Cells divide as time passes, as this occurs they pass through 3 checkpoints G1, G2 and Metaphase.

This is illustrated here  through an animation click on check point for succint descriptions of each checkpoint.

Cells divide a certain number of times, then they die. On average this occurs 30 time per lifespan, then father time takes its toll and ageing then occurs.