BIO130H1 Chapter Notes - Chapter several: Non-Homologous End Joining, Telomere, Mutation Rate
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BIO130H1 Full Course Notes
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Document Summary
Telomere: ttaggg repeated 500-5000 times at ends of chromosome all vertebrates protect dna from nucleases, prevent fusion of chromosomes with one another. Cancer! telomere activity, divide indefinitely centromere: contains alpha-satellite dna, tandem repeat 500, 000 bases. Dna replication semiconservative: daughter duplex = one parental strand, one nascent straned conservative: parents together, daughter together dispersive: parental broken into fragments, new synth. , composites of old & new. Meselson-stahl experiment: used cesium and two weights of n isotopes. Dna replication in bacterial cells temp. sensitive mutants isolated at the nonpermissive/restrictive temp. (deficiency of proteins for replication only at high temp. ) origin of replication: where proteins bind to initiate replication bidirectionally movements of replication forks +ve supercoiling. Dna polymerase i: kornberg enzyme, primer removal and gap-filling (many), and repair. Dna polymerase iii: elongation (fewer), pol iii on lagging strand is connected to polymerase on leading strand replication is semi-discontinuous because there is a leading and lagging strand.
