what is the function of telomeres and telomerase?
what do telomeres and telomerase do in a regular cell?
what do telomeres and telomerase do in a cancerous cell?
Telomeres are the end caps of DNA strands. DNA strands are found in the nuclei of virtually all cells (with the notable exception of red blood cells, which have no nuclei) and — in healthy cells — DNA strands contain all the genetic information required to produce every cell of the organism in which they are found. Although they are part of DNA strands, telomeres contain no genetic information. Rather, telomeres serve the function of bookends, protecting the information on the interior portion of DNA strands. However, when a cell undergoes mitosis, a small portion of its telomeres are lost in the process; in germ cells and stem cells, telomeres are rebuilt by the enzyme telomerase, but in specialized somatic cells, telomerase is typically dormant. In almost all cancer cells, telomerase is reactivated, and the cancer cells go rogue, reproducing with total abandon, forming tumors and spreading to other organs.
In healthy organisms, would-be cancer cells are routinely killed off by the immune system, but when cancer cells figure out how to activate telomerase, it gives them a serious advantage over healthy cells that are playing by the rules. Ideally, telomerase could be activated transiently in healthy somatic cells and de-activated in cancerous cells.
[Edited to fix typo.]