Question

On average, RNA polymerase makes one error for every 10,000 nucleotides it incorporates in RNA. By contrast, only one base-pair error remains for every 10 billion base pairs during DNA replication. Explain why the accuracy of RNA transcription is not as critical as the accuracy of DNA replication.

Answer 1

If you have an inaccuracy in transcription/translation, then it results in an imperfect protein which will be broken down soon after. However, the next protein that is produced will be good and so the effect of an incorrectly transcribed/translated protein is short-lived.

If you have an error in replication, it is carried from cell to cell. And if the error occurs early in life (embryonic stage), then the mistake will be carried in many of the organism's cells. Since the cells will be replicated several times in the course of the life of the organism, the effect of an error is long-lived. This is why mistakes in replication (mutations) can eventually lead to disorders like cancer.

It is better to have one inaccurately transcribed protein which you won't even notice, than to have an error in replication which can, at worst, lead to death of the organism.

Answer 2

Compliments of YA and JiveSly.

Answer 3

Hope this is helpful!