Biology 1001A Lecture Notes - Lecture 6: Atomic Orbital, Non-Homologous End Joining, Pyrimidine Dimer
3 Apr 2016
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Document Summary
Double helical strcuture of dna two antiparallel backbones. Dna polymerase is just on : any cell in s-phase expresses this enzyme. Won"t find telomerase in somatic cells because we want telomeres to shorten: need to know how many times have i divided, after about 50 cell divisions, getting old, getting mutations. Risk of dividing out of control: 50 generations old = should just die = apoptosis. Shortening telomeres is one of the messages that activates apoptosis. Telomerase is active when you make gametes, when preparing dna to give to babies and next generation: adds telomeres so babies inherit chromosomes with ling telomeres. In stem cells, they need longer life span = need to divide more than usual: more telomerase activity. Cancer cells: first thing they do is turn on telomerase so they can divide rapidly. Polymerase can put in wrong base (ex. pairs c with a: a has 2 h bonds, c has 3, mismatch of bases.
