role of telomeres during replication
- what are telomeres?
- how are portions of telomeres lost during replication?
- when are telomeres completely lost?
telomeres and aging
- cell senscence
- Hayflick limit
- telomerase
- how does telomerase function?
- flaws of telomerase
- correlation between length of telomeres and life expectancy
- what can the remaining length of telomeres tell us?
- telomerase in cancerous cells
summary
- Telomeres protect chromosomes from losing essential coding DNA during replication
- Once a chromosome's telomeres are gone, coding DNA is lost with every replication
- The finite length of telomeres puts a limit on the number of times that DNA can successfully replicate and consequently, on the number of times that a cell can divide
- This is known as the Hayflick limit
- Once a cell reaches its Hayflick limit, it begins a period of decline known as cell senescence
- Cancer cells have an abundance of telomerase
- This enzyme keeps their telomeres from shortening and makes them functionally immortal
- Medical therapies that influence the activity of telomerase and alter the length of telomeres may prove effective in the treatment and prevention of some cancers and age-related diseases
questions (pg. 298)