Which clock determines the number of times a cell can divide?

Correct option is A

The telomere is a region of repetitive nucleotide sequences at the end of chromosomes, which protects the chromosome from deterioration. As cells divide, the telomeres shorten, and once they become too short, the cell can no longer divide. This process is often referred to as the "cellular clock" or "Hayflick limit" because it determines the number of divisions a cell can undergo before it enters senescence or apoptosis (programmed cell death).
· Mitvey and Nares are not associated with any known biological clocks related to cell division.
· Biological clock generally refers to physiological processes such as circadian rhythms, not the cell division limit determined by telomeres.
Information Booster:
1. Telomeres protect chromosomes and play a crucial role in aging and cancer.
2. As telomeres shorten, the cell's ability to divide decreases, contributing to aging and the eventual cessation of cell division.
3. Telomerase, an enzyme that adds DNA sequence repeats to the telomere ends, can prevent this shortening in certain cells, such as stem cells or cancer cells.
4. The "Hayflick limit" refers to the number of times a normal somatic cell can divide before cell division stops due to telomere shortening.
Additional Information:
· Telomere shortening has been linked to aging and age-related diseases, while some cancer cells maintain telomere length through the activity of telomerase, which contributes to uncontrolled cell division.
· The biological clock is a broader term and includes various internal rhythms that regulate behaviors and processes like sleep, feeding, and reproductive cycles.