BIO130H1 Lecture Notes - Lecture 6: Nuclease, Proofreading, Dna Repair
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BIO130H1 Full Course Notes
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*for lagging strand the loss of sequence due to the shortenging of 5" end of daughter dna is a problem at the end of chromosomes. In the majority of eukaryotes, this problem is solved by having repetitive dna sequences at the ends of the chromosomes. The repetitive sequence that is added to the 3" end of the parental strand (i. e. the lagging strand template) is determined by the rna template in telomerase. (telomerase, the enzyme, already had rna template, very simple, in it. 1)rna template: resembles: reverse transcriptase (like a polymerase build primers, generates: g-rich ends, adds nucleotides to: 3" ends of parental strand. Getting old=telomere gets shorter since the enzyme, telomerase, decrease. =starts to loose info=cell death. Helicase separates the strands but when the helix built up and form knots and supercoils, helicase can"t progress any further b/s of the torsional stress
