Biology 1001A Lecture Notes - Lecture 6: Human Genome Project, Genome Size, 1000 Genomes Project
10 May 2016
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Document Summary
Shortening telomeres is one of the messages that activated apoptosis. Telomerase is active when making gametes add telomeres: babies inherit chromosomes with long telomeres. In stem cells, those need a long life span and to divide many time therefore have telomerase activity. Cancer cells turn on telomerase so they can divide rapidly. During s phase, replication errors can be repaired. Proofreading: sometimes telomerase can put in the wrong pair ex. Mismatch repair /excision repair: enzymes can identify the bump and break the backbone replacing it with the correct bases and then it seals again. Repair by double strand breaks during g1 by non homologous end joining (nhej) is sloppy and can result in mutation r. Dimers can be repaired by photolyase or excision. If nocturnal you don"t need the photolyase, no consequences to losing it because we were nocturnal, as we became less nocturnal we couldn"t get it back: thymine dimers can also be fixed by excision.
