BIOL 100 Lecture Notes - Lecture 7: Mutagen, Nondisjunction, Meiosis
23 May 2016
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Document Summary
Translocation & cancer: different translocations can cause different cancers. Mutations: any change in dna, these are either spontaneous or induced. Spontaneous: permanent changes in the dna that occur without outside influences. Nucleotides can change structure based on environment. Meiosis is imperfect, nondisjunction can occur and you do not separate sister chromosomes/chromatids. Sometimes crossing over is not perfect and causes problems. Dna polymerase can make an error during replication. Errors are often repaired but if they escaped proofreading, they become permanent errors. Induced: permanent change in the dna and it is caused by an outside agent. These outside agents are known as mutagens. There are many of these mutagen types. Chemical agents cause mutations: nitrous oxide, nitric acid. This interacts with cytosine, converts it to uracil, dna polymerase then encounters this, mistakes u for t, now inserts an a instead of the g that it should have (incorporates the wrong nucleotide: benzo pyrine.
