Exam 2: Chapter 11: Cell Death and Immorality Flashcards
What happens when cells reach their limits?
They die or enter a state of senescence
What is Senescence?
Cells stop dividing and become metabolically inactive but remain alive
Why are some cells from older donors only capable of fewer populations
Cells have an internal clock that stops them from dividing after a number of doublings
What are Telomeres?
A region of the DNA at the end of each chromosome that protects the structure of the chromosome
What happens to the telomere when a cell divides
The telomere gets shorter. This leads to cell death or senescence
Why are telomeres needed?
They are DNA repair mechanisms for double stranded breaks by forming a molecular configuration called a T loop
Explain Cell immorality?
Telomerase stops being expressed in somatic cells after early development. Cells become mortal with finite life span
Why do somatic cells become mortal?
Loss o cell immorality might be a defense mechanism against cancer
What happens when telomeres get too short?
Cells are inappropriately targeted by DNA double stranded break repair mechanisms
What is the role of telomeres in Cancer?
Cancer cells lose their telomeres, however a small number of cancer cells re-express telomerase causing them to repair the telomere and re-stabilize chromosomes again.
