Cell los and atrophy

Cells can’t live forever, except for cancer cells (these live forever if they are preserved in the right conditions). The number of times that a cell can divide is called the Hayflick limit. For a human cell this limit is about 52 times. But how does a cell know how many times that she’s already divided? Well the answer is because a cell uses a mechanism to count this. This mechanism are the telomeres. The telomeres are pieces of DNA on the end of the DNA molecule that doesn’t code for the production of proteins. When the cell divides the DNA is replicated and the telomere becomes shorter. When there isn’t any more telomere, the vital DNA would become shorter and the cell wouldn’t be able to produce the right kind of proteins. So the cell commits suicide. Cancer cells produce an enzyme called telomerase that lengthens the telomeres and by doing so prevent the cell from dying. Now researchers search drugs that inhibit telomerase and this makes cancer cells mortal. A good example of cancer cells' immortality is HeLa cells, which were originally removed from the cervical cancer of Henrietta Lacks in 1951 and are still used in laboratories as a model cell line. They are indeed immortal - daily production of HeLa cells is estimated at several tons even up to this day - all from the few cells taken from Ms. Lacks' tumor.