Final answer:
The key interaction regulated in telomere equilibrium is the activity of the enzyme telomerase, which adds repetitive sequences to telomeres. This prevents shortening and allows cells to maintain their chromosome integrity and avoid premature aging.
Step-by-step explanation:
The key interaction that is regulated in telomere equilibrium is the activity of the enzyme telomerase. Telomerase is responsible for adding repetitive sequences to the telomeres, preventing them from shortening during each round of cell division. This allows cells to maintain their chromosome integrity and avoid premature aging.
Telomerase is typically active in germ cells, adult stem cells, and some cancer cells. It is not active in adult somatic cells and may be associated with the aging of these cells. The discovery of telomerase and its action was a significant advancement in our understanding of how chromosome ends are maintained.