BIOL355 Lecture Notes - Lecture 17: Hayflick Limit, Telomerase, Telomere
21 Apr 2017
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Document Summary
Enzyme, telomerase restores the telomeres so that their length stays the same in germ cells such as sperm or eggs. Telomerase is absent in fibroblasts of the skin, the telomere resembles a timer that marks off cell divisions so telomeres continue to contract to the point when the cell dies or enters a senescent state. When telomerase is reactivated in the lab, some normal cells have their life extended indefinitely. Such reactivated occurs naturally in most cancer cells. Immortal cells such as cancerous cells have a constant telomere length. Telomeres lost faster from individuals with progerias. Blood vessels under turbulent blood flow show shorter telomeres than straight sections. Oxidative stress (free radicals) speed up telomere shortening. Centenarians and their offspring maintain a longer telomeres compared to controls with advancing age; longer telomeres are associated with protection from age-related diseases, better cognitive function and lipid profiles of healthy aging.
