BIOL 4246 Chapter : 6 27 12 DNA Repair
Document Summary
Deamination of c causes uracil, the cell can handle it. It deaminates that 10x the rate that cytosine does and deaminates to thymines. There"s no enzyme to remove thymine, but the vsp (?) system targets the dcm methylase which attacks the. Adaptive mutagenesis- when the cell is stressed, starved, dna damage. Dna pol iv- causes -1 deletions to force frame shifts which turn on and off free genes. Some cells on/off give the cell an advantage. Mutator genes- any gene which leads to an increase in the rate of mutations in all genes when it is mutations. Umu, cnd, muthls, mutu, mutd=dnaq proofreading for dna pol iii. Repair of pyrimidine dimers: dna repair- you can"t replicate through a bulky lesion, to deal with the dimers, photo reactivation- nonessential in bacteria. Uses an enzyme called photolyase- encoded by the phr gene. Activated by visible light, uv light is found in sunlight.
