Programmed cell death, also known as apoptosis, is an essential process for development and removing damaged or old cells. Apoptosis helps shape tissues during development and removes cells exposed to DNA damage from sunlight, viruses, or chemicals. As cells divide and age over time, the protective caps on the ends of chromosomes called telomeres get shorter with each division, triggering apoptosis after a cell has divided approximately 30 times to remove old or damaged cells.
