# Telomere --- A **telomere** is the end bits of a [[chromosome]]. Unfortunately a little bit of the strand doesn't get fully [[DNA replication|replicated]], it shortens a little bit with every replication. Fortunately telomeres are comprised of short repeating sequences, so for the most part we don't loose anything important, until we have gone through so many replications that the telemere runs out. ## Telomerase **Telomerase** is a special [[enzyme]] that lays down an extension of the telomere. Telomerase has a template of the telomere's repeating sequence in RNA, so it can use that to lay down extra DNA track. This allows [[DNA replication#Step 2 Laying The RNA Primer|DNA primase]] to come along, lay down the primer, and then [[DNA polymerase]] can do it's job as well. Telomere maintenance is done at a very high level as embryos, but goes away as we age. ___