Which concept refers to a genetic timer in cells that regulates aging by hormonal changes and cellular repair processes?

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

Answer: (B)

A genetic clock is an intrinsic timeline encoded by our genes that can influence when aging-related changes occur. This idea suggests that as time passes, gene expression patterns and hormonal signals shift in a regulated way, guiding cellular repair, maintenance, and metabolic processes. In other words, hormones can modulate how effectively cells repair damage or how quickly they accumulate wear, aligning aging progress with an internal timing program. That combination of gene-driven timing and hormonal influence is what the concept of a genetic clock aims to capture.

The other ideas describe important aspects but not the timing mechanism itself. The Hayflick limit explains why normal cells can divide only a certain number of times before entering senescence due to telomere shortening, which is about replicative capacity rather than an overarching timed program. Cellular aging refers to the overall process of aging at the cellular level without specifying a regulatory timer. Changes in brain functioning describe neural or cognitive changes associated with aging, not the cellular scheduling mechanism.