Tag Archives: telomerase rna dependent dna polymerase

Telomerase Rna Polymerase

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What does a Promoter and Origin of Replication have in common?

a. They are both sites of action by an RNA polymerase
b. They are both sides of action by a DNA polymerase
c. They are both sites bidirectional nucleic action polymerization
d. They are both sites of telomerase action.

I believe the promotor is only used in transcription (RNA poly), and origin of REPLICATION signifies DNA replication (DNA poly), and I know RNA polymerase transcribes unidirectionally downstream from the promoter. I guess that only leaves D, but I can’t find anything anywhere relating those two to telomerase action. Help please..

Your reasoning sounds correct, but I think the answer would be A. DNA replication also involves synthesizing a small RNA primer for the lagging strand. This is done by primase which is a type of RNA polymerase.

RNA polymerase II

Telomerase Rna

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Why do telomeres eventually shorten as chromosome replication occurs?

I know that telomerase adds repetative sequences using a reverse RNA transcriptase to cover the gap on the 3 prime end, but why does this gap eventually form?

in order to change RNA to DNA, there must be another DNA strand in front of the RNA primer. This happens at all the sites of the lagging strand, but it doesn’t happen at the end where the last RNA primer is attached. Ultimately, that RNA is destroyed by enzymes that degrade RNA left on the DNA. Thus, a section of telomeres is lost during each cycle of replication at the 5′ end of lagging strand.

Looks like all gaps can be covered except at the very end.