Please read and answer all parts. 45. - 48. Here are three quotes from an printe

Question

Please read and answer all parts.

45. - 48. Here are three quotes from an printed interview with Francis Collins (look him up),
i. " Collin’s lab team found that in cells growing in the lab, when they used a chemical to un-cap the chromosome ends, it altered gene splicing and led to progerin production and
cellular senescence.

ii. “It’s clear that progerin turns on as a cell is approaching senescence,” Collins said.

iii. “While I can’t prove it, it seems likely that progerin itself is part of normal, programmed senescence,” Collins said. “If we understood that, maybe we would be able to come up with
a strategy to deal with the process of normal aging.”

a) We've heard that before, that gene splicing alters with age - what does that mean?

b) According to statement ii, they were comparing artificially made senescent cells to the cells of people with what condition?

c) When stating that progerin production is part of normal aging, what theory of aging is he implicitly endorsing? Explain.

Explanation / Answer

a) We've heard that before, that gene splicing alters with age - what does that mean?

Chromosomal ends are capped with telomeres. Due to number of cell divisions, due to aging of the cell, the telomere ends degrade leading to aging of the cell and thus death of the cell. As the telomere end shortened more progerin gets produced which is a mutated version of natural protein lamin A. Thus shortening of telomeres leads to abnormal synthesis of progerin instead of lamin A. The reason is interrupted splicing of lamin A mRNA affecting the protein production.

b) According to statement ii, they were comparing artificially made senescent cells to the cells of people with what condition?

The researchers compared the artificial senescent cells with senescence due to aging.

c) When stating that progerin production is part of normal aging, what theory of aging is he implicitly endorsing? Explain.

The theory of programmed longevity states that "the internal genetic program contains the information for the cell reproduction and death and aging follows a built in genetic clock with a prescribed biological time table for senescence to occur". It states growing age is not result of a series of random events but genes program age related molecular and cellular changes. So, the theory states that aging is due to certain genes switch on or off; senescence is the period of biological clock of aging at which age associated deficits occurs.

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