True about telomerase is:

Telomerase is a ribonucleoprotein paicle required for telomere maintenance. Telomerase contains an RNA that serves as the template, not the primer, for the synthesis of telomeric DNA by the reverse transcriptase of telomerase. Telomeric RNA has no catalytic activity. As a reverse transcriptase, telomerase synthesizes DNA using its RNA template and so is an RNA-Dependent DNA polymerase. Telomerase is highly active in the early embryo, and after bih it is active in the reproductive and stem cell Telomerase activity high in cancer cell Its maintain cell longevity