Biochemistry 2280A Lecture Notes - Lecture 18: Dna Mismatch Repair, Dna Replication, Pyrimidine Dimer
18 Nov 2016
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Topic 16 learning ocjectives: different kind of dna damage, dna repair mechanisms, which repair mechanism fixes what damage, consequences of unrepaired dna damage, translesion dna polymerases. Dna damage = any unintended physical or chemical change in the dna: most of the time is deleterious or harmful, but there are some cases of beneficial damage. We pretty much always try to fix dna. Why: don"t fix if it aint broke. If there is a base missing: we use the complementary strand to give us into to fill in the right base: another example of why complementary strands are awesome. Cause of dna damage: mutation is double stranded: copying mistakes: dna polymerase makes an error once every ~107 nucleotides. Causes a distortion in dna: mismatch: unrepaired replication error, insertions, deletion, depurination: loss of a or g base. Can get lucky or can get a mutation: would rather a mutation than not move past.
