Function Telomerase

[mage lang=”en|es|fr|en” source=”flickr”]function telomerase[/mage]
Question concerning DNA Synthesis?

How does the telomerase solve the problem of replicating linear DNA?
What would happen to DNA if the DNA telomerase did not function.

I am confused about what my book says about it. Can someone give me an easy explanation?


Telomerase is a type of reverse transcriptase. When DNA is replicated, because it can only be copied 5′ to 3′, the ends don’t get copied and there is some loss of base-pairs at the end of the long DNA chain. So every time DNA gets copied, if there wasn’t any telomerase, the DNA would get shorter and shorter. Luckily, there are these repeating (non-coding) sequences at the end of the DNA and at the end of replication, even though replication did not continue all the way to the end, telomerase adds some more repeating sequences to prevent these non-coding sequences from getting too short. telomerase uses an RNA primer to add deoxynucleotides to chromosome telomere. If they get shorter with each replication, eventually you will start losing some coding sequences at the end of the chromosome. Despite the presence of telomerase, this still happens and is believe to be a cause of aging. Some cells (tissues) seem to have more telomerase activity than others. And it is not unusual for people in their 70s and 80s to have telomere shortening.

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