Question

Describe one mechanism from which cell senescence occurs.

Answer 1

Cell senescence:

1. Cell senescence is an irreversible cell arrest mechanism.
2. It protects the body against cancer.

Telomeres shortening for cell senescence:

1. Cells can undergo arrest in response to various extrinsic and intrinsic stimuli.
2. These involve telomere shortening, oncogenic activation, radiation, oxidative and genotoxic stress, and mitogenic signals.
3. Telomeres shorten due to cellular replication, leading to a permanent cell cycle arrest.
4. This is known as replicative senescence.
5. Telomeres shorten due to the intrinsic inability of the enzyme DNA polymerase to completely replicate the telomere C-rich lagging strand.
6. This phenomenon was given by Olovnikov and Watson.