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Old 25th July 2015, 01:05 AM
Real Old Lady Real Old Lady is offline
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Join Date: Jul 2015
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Default Re: Any Scientist can help me?

Thanks guys for the info.

The theoretical life expectancy, based on the basal rate of telomere shortening, is 125 years. Only one person have ever lived past 121years (122yrs). Most scientist predict the average life expectancy to continue to increase, but most doubt that the average would go any higher than 90 year. Scientist can now determine from the length of the telomere, not only the age of the individual, but when the individual will die. We begin with 15000bp as an infant, and die with around 5000bp. I know that there are some species that have longer telomeres(mice) and have shorter life-spans, but this is only evidence that telomere length alone do not dictate life-span.

When DNA begins to unwind into 2 strands (the enzyme DNA Polymerase) to replicate, it needs a small piece of RNA (primer), which is attached near the end of one DNA strand to begin copying that strand. Since the primer does not attach to the very end of the strand, when the cell divides, the entire DNA strand is not copied. As cell division continues, the end section of each DNA strand will continue to get shorter and shorter. We can lose 50-250 base pairs with every cell division. Telomeres are the repeated sequences of base pairs on the end of DNA strands. They protect the DNA strand from getting shorter during cell division. In germline cells (egg or sperm), or cells that rarely divide, (heart), the enzyme telomerase is responsible for adding more repeat sequences on the end of the DNA strand, thus making those cells immortal. If this didn't occur the organism would soon become extinct. In Somatotropic cells (muscle, skin, blood, bone, etc.), telomerase function at much lower levels, thus making those cells mortal. When somatic cell telomeres shorten to a critical level(5000 base pairs), the cell will no longer divide and cell death will follow. Telomeres can also effect Gene expression much like Enhancer Sequences folding over and contacting a Promoter. If the Telomere is to short, it won't be able to fold back to turn on/off genes.

I do understand that other factors such as, oxidative stress, glycation, or just the risk factors associated with chronological age, all effect why we age and die naturally.

My query was, if the same amino acid is coded by more than one triplet codon(synonym), and that amino acid becomes part of a protein, will the nature of the protein be effected by the nature of which codon is used? I'm not sure if this is a valid this question or not. Thanks guys. Shell
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