Which statement about telomeres and telomerase is true?

• A. Telomeres degrade DNA.
• B. Telomeres cap the ends of chromosomes.
• C. Telomerase caps telomeres.
• D. Telomerase is present in all normal cells.

Answer: (B)

Telomeres act as protective caps at the ends of chromosomes, guarding genetic information during replication. Each time a cell divides, a little of the telomere is lost, which helps limit how many times a cell can divide. Telomerase can rebuild telomeres by adding repeats, but it isn’t active in all normal cells—it's mainly active in germ cells and many cancer cells, while most somatic cells have little or no telomerase. So the statement that telomeres cap the ends of chromosomes is the true one, while the other ideas—telomeres degrading DNA, telomerase capping telomeres, or telomerase being present in all normal cells—don’t fit what we know about their roles.