[31] Telomeres and Telomerase in Aging and Cancer Flashcards
What are Telomeres?
Protective caps on the ends of chromosomes.
What is the function of Telomeres?
They protect the ends of chromosomes from deterioration or fusion with neighboring chromosomes.
What happens to Telomeres as cells divide?
They shorten.
What is the role of Telomerase?
It adds DNA sequence repeats (“TTAGGG” in all vertebrates) to the 3’ end of DNA strands in the telomere regions.
What is the effect of shortened Telomeres on a cell?
It can lead to cell senescence or cell death.
How are Telomeres linked to Aging?
The shortening of Telomeres is associated with aging and age-related diseases.
How are Telomeres linked to Cancer?
Telomerase, which elongates Telomeres, is often reactivated in cancer cells, allowing them to divide indefinitely.
What is the ‘End Replication Problem’?
The inability of DNA polymerase to fully replicate the ends of linear chromosomes, leading to telomere shortening.
What is the role of the Shelterin complex?
It binds to and protects telomeres, and regulates telomerase.
Shelterin - Initials
A protein complex that protects telomeres
What happens when Telomerase is overactive?
It can lead to unlimited cell division, a hallmark of cancer.
How can Telomere length be measured?
- Terminal Restriction Fragment analysis
- Telomere Repeat Amplification Protocol
- Quantitative PCR
What is the Hayflick limit?
The number of times a normal human cell population will divide before cell division stops, due to telomere shortening.
What is ‘Telomere Crisis’?
A stage in cancer development where cell division continues despite critically short telomeres, leading to genomic instability.
What is the role of Telomerase in stem cells?
It is active and maintains telomere length, allowing stem cells to divide more times than somatic cells.
