Biology And Biomedical Sciences BIOL 2960 Lecture Notes - Lecture 23: Nonsense Mutation, Tumor Suppressor Gene, Allele
13 Dec 2016
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Document Summary
A base pair change, deletion, insertion etc. Generates a new allele: a chromosomal mutation is an alteration of chromosome structure or chromosome number. Ionizing radiation (x-rays, cosmic rays, radon) can result in single and double strand dna breaks. Uv radiation and sun exposure can result in pyrimidine dimers. Chemicals (such as chemotherapy reagents, psoralens, aflotoxins) can result in damage to bases and cross linking (large distortions) Oxidation (as a result of normal cell metabolism) results in oxidative damage: the deamination of cytosine (to uracil) and the oxidation of guanine (to 8- oxoguanine) can cause base pair mismatches. Uracil will then h-bond to a resulting ultimately in gc at substitution. 8-oxoguanine will h-bond to a resulting ultimately in a gc at substitution. Dna repair: overview, mutation and dna damage are constantly occurring, an estimated several thousand lesions per cell per day occur in the human body, result: cells have extensive and redundant pathways for repairing damaged dna.
