BSCI 105 Lecture Notes - Lecture 15: Dna Mismatch Repair, Gene Duplication, Pyrimidine Dimer

• School: University of Maryland
• Department: Biological Sciences Program
• Course: BSCI 105
• Professor: Keller

Document Summary

Can be caused by: errors during replication, damage to dna, chromosomal rearrangements. Point mutations: single nucleotide changes, can result in. Silent mutations same product, no effect. Indel mutations: insertions or deletions, result in frame shift mutations. Regulatory mutations: point mutations, insertions, and deletions also occur in non-coding dna, mutations in regulatory sequences can alter gene expression. Proofreading: dna polymerase iii, each added nucleotide is compared to the template, errors in base pairing are detected during dna replication, polymerase removes the last nucleotide, backs up, then continues dna synthesis. Mismatch repair: repairs errors in synthesis that were missed by proofreading, repairs changes in nucleotides caused by dna damage, detects distortions in the double helix from incorrect base pairing, detect error, detect methylated template, excision, fill-in, ligation. Nucleotide excision repair: similar to mismatch repair, detects and repairs damaged dna. Chemical modifications: uses undamaged strand as template, detection, excision, fill-in, ligation.