DNA polymerase

DNA polymerase is the watchman of our genetic information. which maintain the copy number of DNA by replication and protect it by damage.. In the bacterium Escherichia coli, the polymerization of 4.64 million nucleotides is necessary to duplicate the genome for the new cell. In all cells, the DNA polymerases are the protein catalysts that link together the nucleotide building blocks of the new DNA polymer in an accurate and timely process.
All this process has been done as perfectly as possible, so that the information is not corrupted. The four bases- adenine, thymine, cytosine and guanine can also form improper pairings, albeit with significantly weaker binding strength. If DNA polymerase relied only on the difference in pairing strength between proper matches and improper matches, it would make a mistake once in 10,000 nucleotides. This would introduce far too many mutations when our genome of six billion nucleotides is duplicated. So the DNA polymerases are also required to repair the DNA of the genome. The genome's DNA can be damaged by either exogenous or endogenous. The damage, if not repaired, could result in the production of mutations in the genome or possibly cell death. Several DNA repair processes occurring in the cell maintain the integrity of the genome by removing the damaged nucleotides and resynthesizing DNA by the DNA polymerases.
No doubt, the evolution of life on the Earth would not be possible without mutations. If cells could reproduce DNA perfectly always, the Earth will never able to change and never progressing to fill new environmental niches means the occasional mutation, when combined with natural selection, adds diversity to life, building slowly over millennia to yield the biosphere we enjoy today. However, these mutations can have a terrible cost at the individual level: they occasionally modify a key protein and lead to cancer. Cells do their best to control mutation, keeping each of us as healthy as possible.