BIOL308 Lecture 8: Lecture 8- DNA repair
11 Jun 2017
School
Department
Course
Professor
Document Summary
In bacteria and yeast: several % of their genome"s coding capacity contains genes encoding proteins involved in dna repair. Dna structure is well designed for repair: if one strand is damaged, the complementary strand serves as a template for repair (back-up copy) Dna replication errors: errors that were not detected and corrected by dna polymerase i and iii proofreading mechanisms. Spontaneous changes in dna (around 5000 depurinations/human cell/day & around 100 spontaneous diminution of c into u /human cell/day) Impact on dna, they can act as mutagens, chemical mutagens too. Replication error: example g inserted instead of a. Lots of replication errors are corrected immediately by dna polymerase and mismatch repair. If not, will most likely be corrected by other repair mechanisms. If escapes scrutiny there are other way to fix the errors. Dna replication without mismatch repair: 1 per 107 nucleotides. Dna replication with mismatch repair: 1 per 109 nucleotides.
