BIOLOGY 1A03 Lecture Notes - Lecture 16: Nitrogenous Base, Chromosome, Nonsense Mutation

• School: McMaster University
• Department: Biology
• Course: BIOLOGY 1A03
• Professor: Rosada Silva

Document Summary

Spontaneous mutations are the most common mutations that occur. Rna viruses have the most probability to incur a mutation of all viruses: there is no proofreading capability in rna genomes. Somatic cell mutations: the earlier the mutation occurs, the larger the spread of the mutated somatic cell throughout the body of an organism: these mutations are not passed down to progeny. Germline cell mutations: mutations in the cell that come together to produce new offspring: passed to progeny. Nucleotide excision repair: removes and replaces more than one damaged nucleotide base at a time, damaged bases signal specific enzymes to cleave the dna backbone, dna synthesis then fills the excised gap with correct nucleotides. Point mutation: small scale mutations: single nucleotide pair substitution: one base pair is incorrectly replaced by another(also called single nucleotide polymorphisms (snps)) Non-synonymous/silent: a nucleotide may transfer one codon into another that is translated into the same amino acid causing no consequential changes.