Which concept is a purported mechanism in the DNA of cells that regulates aging by triggering hormonal changes and controlling cellular reproduction and repair?

• A. Cellular aging
• B. Genetic clock
• C. Hayflick limit
• D. Changes in brain functioning

Answer: (B)

The genetic clock is the idea that aging is governed by an internal timing system encoded in our DNA, which influences when cells divide, repair, or enter senescence and coordinates hormonal changes that affect aging. This concept frames aging as a programmed process tied to gene expression and cellular signaling, rather than just accumulated damage over time. The Hayflick limit describes the maximum number of times a normal cell can divide due to telomere shortening, which is part of the mechanism leading to senescence but is more a constraint on divisions than the broad timing system itself. Changes in brain functioning describe outcomes or manifestations of aging, not the DNA-encoded mechanism that regulates aging. So the genetic clock best fits as the concept described.