Which statement correctly describes the function of telomerase?

• A. Telomerase uses a DNA template to extend telomeres.
• B. Telomerase is a ligase that extends telomeres.
• C. Telomerase extends telomeres using an RNA template.
• D. Telomerase extends telomeres by recombining adjacent sequences.

Answer: (C)

Telomerase acts as a specialized reverse transcriptase that carries its own RNA template. It extends chromosome ends by using that RNA template to guide the synthesis of new DNA repeats, thereby adding telomeric sequences to the 3′ end and offsetting shortening that happens with DNA replication. In humans, the RNA component provides the exact sequence to be copied into DNA, so telomere elongation relies on RNA-templated DNA synthesis rather than using a DNA template or by recombining nearby sequences. This makes the RNA-templated mechanism the correct description of how telomerase functions.