Wonderful changes take place in a human body as we age. Have you ever wondered what makes our hair gray or white? What makes our skin grow pale? What makes your bones porous? All of these have a common answer and that is, the cells are shrinking.
To be more specific the telomeres are the external protecting feature of a chromosome and they are shrinking as they age. After careful research it was found that these telomeres are the key to the age identification. Apart from involving in aging process these telomeres are involved in complex mechanisms of cell division and in cancer. Scientists have started realizing that understanding these components will help them do research in aging process and in cancer.
In a recent research at the Rockefeller University, it was found that there is a concept called the molecular clock and the organism's starts cell division based on this clock. When the molecular clock is very old pointing to an aged cell, then the telomeres are shrunk. The research work says that the cell stops functioning its normal function at point in time and this point is decided based on the age of the cell. There exists no abrupt stop of functionality in the cell. The deterioration is slow and steady in the cells. There comes a time in the biological clock where the cell can live for that time.
Lifetime of a cell does not clearly mean the lifetime until it replicates, it is even beyond that point. Lifetime of a cell is the span from the time it was formed until it keeps replicating on and on and finally, there is one small cell, yet the biological clock has determined that the cell has crossed the age of living and that young cell is no younger and it is ready to die. This end determines the cells can no longer replicate and they have to be still to retire soon. The biological clock could be nothing more than the telomeres, which have a certain length. This length keeps reducing with every cell division.
This means that the parent cell will have a lengthier telomere than the two daughter cells and this goes for several generations. There will come a time where the length of the telomere is very short for the survival of the telomere and hence the cell division stops at that point.
Source : Enzine
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