1.Telomeres and Aging. Review the following article (http://learn.genetics.utah.

Question

1.Telomeres and Aging. Review the following article (http://learn.genetics.utah.edu/content/basics/telomeres/) and answer the following questions. A few sentences per part should suffice – do not copy and paste your answer from the article, it should be in your ow words. (Long answer- 100-200 words min)

What is the function of the telomere in the cell?Why do telomeres shorten with each cell division?How big is the role of telomeres in aging?What factors work together in conjunction with telomere shortening to contribute to the aging process?

2.Please explain in a minimum of 50 words your eureka moment during the class?  What was most interesting to you?

Explanation / Answer

Function of Telomere

Telomere Shortening

In cells lacking sufficient levels of the enzyme telomerase, telomeres progressively shorten with cell division as a result of the end replication problem andor oxidant stress. The enzyme telomerase can add new repeat sequences to the ends of chromosomes, which stabilizes the telomeres and ensures proper telomere length. Excessive shortening can lead to improper segregation of chromosomes during cell division, genomic instability, and the initiation of tumorigenesis. Oxidative damage can result in telomere shortening also.

Roles of Telomere in Aging

Telomeres play a central role in cell fate and aging by adjusting the cellular response to stress and growth stimulation on the basis of previous cell divisions and DNA damage. At least a few hundred nucleotides of telomere repeats must "cap" each chromosome end to avoid activation of DNA repair pathways. Repair of critically short or "uncapped" telomeres by telomerase or recombination is limited in most somatic cells and apoptosis or cellular senescence is triggered when too many "uncapped" telomeres accumulate. The chance of the latter increases as the average telomere length decreases. The average telomere length is set and maintained in cells of the germline which typically express high levels of telomerase. In somatic cells, telomere length is very heterogeneous but typically declines with age, posing a barrier to tumor growth but also contributing to loss of cells with age.

Factors work together in conjunction with telomere shortening to contribute to the aging process

The identification of telomeres as an important structure for maintaining genetic stability and description of their role in regulating cellular senescence provided insight on the mechanisms of aging at a molecular level. Telomere length (TL) has emerged as a promising bio-marker to assess the cumulative influence of psychosocial, environmental, and behavioral factors on complex disease risk (especially cancer).

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