Final answer:
Telomeres consist of repetitive sequences at chromosome ends and protect genomic integrity during cell division, with telomerase adding these sequences. Telomerase activity is significant in germ cells and stem cells, and its study could help address aging and cancer.
Step-by-step explanation:
Telomeres are the protective caps at the ends of linear chromosomes, consisting of repetitive sequences that do not code for any particular gene. These telomeres play a crucial role in genomic stability as they prevent the loss of coding sequences throughout cellular divisions. The characteristic sequence in humans is TTAGGG, repeated between 100 to 1000 times at each chromosome end. An enzyme called telomerase is responsible for adding these repetitive sequences to the telomeres.
Telomerase has a catalytic part and a built-in RNA template which allows it to extend the 3' end of the chromosome by adding nucleotides complementary to the RNA template. This activity is particularly important in germ cells, adult stem cells, and certain cancer cells. The enzyme is not typically active in adult somatic cells, which is associated with cellular aging as telomeres progressively shorten with each cell division, eventually leading to cellular senescence or apoptosis.
The study of how to lengthen telomeres is significant because it may have implications in delaying the aging process, improving cellular function in age-related diseases, and controlling cancer where telomerase activity is often upregulated, allowing uncontrolled cell proliferation.