BIO 201 Lecture Notes - Lecture 34: Dna Mismatch Repair, Ionizing Radiation, Mutation

• School: University at Buffalo
• Department: Biological Sciences
• Course: BIO 201
• Professor: Lara Hutson

Document Summary

Lecture 34: mutations, dna damage, and repair (ch. Errors in replication (primary cause of heritable mutations) Dna polymerase error rate: ~1 error per 100,000 bases. Review: base pairing and structures of purines vs. pyrimidines. Replication errors are usually point mutations (i. e. single-nucleotide) Transitions: purine purine (a g; g a, pyrimidine pyrimidine (c t; t c) Transversions: purine pyrimidine (a or g c or t, pyrimidine purine (c or t a or g) Transitions do not alter the structure of dsdna. Dna polymerase error rate: ~1 error per 100,000 bases (human genome 6. 6 10^9 bases) . ~66,000 mutations per generation (33,000 per daughter cell) Observed mutations: ~6 mutations per generation (3 per daughter cell) Dna polymerase cannot add a new nucleotide until the last nucleotide is correctly base-paired with the template. If the last base is not correctly base-paired, it uses 3" e(cid:454)o(cid:374)u(cid:272)lease a(cid:272)tivit(cid:455) to re(cid:373)ove (cid:373)ost recent base. Dna polymerase incorporates the correct base and continues.