AP BIOLOGY

Detailed explanation-1: -Telomerase has a protein subunit (hTERT) and an RNA subunit (hTR). This enzyme is active in germline and stem cells and maintains their telomere length by adding ‘TTAGGG’ repeats to the ends of chromosomes. Therefore, telomeres do not shorten in these types of cells.

Detailed explanation-2: -A telomere is a region of repetitive DNA sequences at the end of a chromosome. Telomeres protect the ends of chromosomes from becoming frayed or tangled. Each time a cell divides, the telomeres become slightly shorter. Eventually, they become so short that the cell can no longer divide successfully, and the cell dies.

Detailed explanation-3: -“But these findings indicate that telomeres may lengthen to the degree that people change how they live. Research indicates that longer telomeres are associated with fewer illnesses and longer life.”

Detailed explanation-4: -Telomeres protect chromosome ends from fusion and from being recognized as sites of DNA damage (Box 1). Dysfunctional telomeres, arising by critical shortening of telomeres in normal somatic cells during progressive cell divisions, elicit DNA damage responses (DDRs) that trigger cellular senescence.

Detailed explanation-5: -Your DNA strands become slightly shorter each time a chromosome replicates itself. Telomeres help prevent genes from being lost in this process. But this means that as your chromosomes replicate, your telomeres shorten. That’s where an enzyme called telomerase comes in.