Biology 1001A Lecture Notes - Photolyase, Pyrimidine Dimer, Body Plan
Document Summary
Difference between dna damage and mutation: mutation is a change in the double-stranded sequence (anything that messes w/ the. H-bonds btw nucleotides will cause a problem during replication) It takes 2 rounds of replication to get a mutation: damage is a change in only 1 strand. Mechanism by which tautomeric shifts in dna bases leads to alternative base pairing. Steric repulsion pushes n-h and n-h apart. An h-bond can form (bottom: ac, by tautomerizing from 1 form to another we can affect h-bonding. Mechanism by which unstable base analogues cause mutation. Some mutagens are tautomerically unstable base analogues bromo. Dna by: dna polymerase can"t distinguish 5- uracil from thymine easily base analogue that gets incorporated into mistake, usually incorporated across from a. In some organisms, dna polymerase relaxes pairing rules to get through the dimer by sticking in a random base.