What is the role of telomerase in cells?

• A. Degrades telomeres
• B. Caps ribosomes
• C. Repairs double-strand breaks
• D. Synthesizes telomeres in germline and some cancer cells

Answer: (D)

Telomerase’s role is to elongate telomeres, the protective ends of linear chromosomes. It carries its own RNA template and uses reverse transcription to add repetitive DNA sequences to the 3’ end, offsetting the shortening that happens with each round of DNA replication. This maintenance is crucial for cells that divide many times, especially germline cells and many cancer cells, where telomerase remains active to keep telomeres long enough for continued proliferation. Because of this, germline and some cancer cells show telomerase activity, while most somatic cells do not and thus gradually lose telomere length.

The other options don’t fit because telomerase does not degrade telomeres, it does not cap ribosomes, and it is not mainly a repair enzyme for double-strand breaks.