How do cells make mistakes during the process of DNA replication?

Question

Why don't they make the same exact copies to themselves rather than making errors during replication, which leads to genetic variation?

Answer 1

DNA polymerase, the enzyme that copies DNA, is error prone. It occasionally incorporates an incorrect base during DNA replication. Most of these errors are corrected, because DNA pol also can proofread and correct its errors, but the enzyme doesn't correct them all. This is a good thing, because these mutations are the source of new traits, and underly the process of evolution.

Answer 2

The process of DNA replication is remarkably accurate. Errors occur only once every 10^9 - 10^10 nucleotides incorporated.



DNA polymerases, however, are not nearly so accurate. They make mistakes once every 10^4 - 10^5 nucleotides incorporated. The proofreading activity of a polymerase will improve the overall error rate by 10^2 - 10^3 but this still leaves a difference of 10^2 - 10^3 in the error rates between DNA synthesis and replication.



This difference is accomodated by mismatch repair systems which quickly fix any errors made during replication...

Answer 3

Interphase Interphase is the growth section wherein the cellular doubles in volume. It precedes mitosis (branch of the genetic cloth) and cytokinesis (branch of the cytoplasm) ensuing in 2 daughter cells ). specifically circumstances cytokinesis is seen the final component of mitosis, on an identical time as in different supplies it is going to likely be stated to maintain on with mitosis. Interphase has 3 subphases: a growth section, a DNA synthesis (or replication) section wherein the DNA doubles, and a 2d growth section Interphase(G1 -> S -> G2) -> Mitosis/Cytokinesis -> Interphase etc.

Answer 4

Placing one base in for another base. Skipping the reading of a whole triplet of bases. Running many repeats of a section of DNA. Leaving out a base.

Some of the above have neutral effect, some have very deleterious effect on the protein coded for and a few have a beneficial effect on the coded protein against the immediate environment....!!