BIOLOGY 201LA Study Guide - Midterm Guide: Homology Directed Repair, Dna Mismatch Repair, Pyrimidine Dimer
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Describe the 3 dna repair pathways discussed in lecture: mismatch repair, direct reversal, ber. Describe the function of muth in mismatch repair. Muth identifies the template strand and nicks newly synthesized strand. Describe 2 functions of the ada protein in direct repair of alkylated dna. Ada repairs is involved in direct repair of thymine dimers. Ada protein recognizes and binds to methylated nucleotides directly removes methyl group and transfers it onto itself: protein becomes methylated in process. Ada becomes a transcription factor and is activated for transcription when it is methylated: more damage more ada. Because dna is more important, all products are made from this. Explain how tautomers result in mutations in dna. Name 2 enzymes are shared by dna repair pathways and dna replication. Describe the mechanisms of 2 direct reversal dna repair pathways discussed in class. Can you envision a mechanism by which photolyase activity might increase in response to uv damage.