BIO130H1 Lecture Notes - Lecture 6: Telomerase Rna Component, Okazaki Fragments, Reverse Transcriptase
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BIO130H1 Full Course Notes
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What happens at the ends of chromosomes: orange = parental strand, back stitching starts close, then goes back. The problem at ends of chromosomes: black = parental strands (anti-parallel) In the majority of eukaryotes, this problem is solved by having repetitive dna sequences at the ends of the chromosomes. Flappy ends will base pair to themselves, creating a loop. The repetitive seque(cid:374)(cid:272)e that is added to the (cid:1007)" e(cid:374)d of the pare(cid:374)tal stra(cid:374)d (cid:894)i. e. laggi(cid:374)g stra(cid:374)d te(cid:373)plate(cid:895) is determined by rna template in telomerase. Telomerase has rna template it uses to make dna complimentary copy: rna te(cid:373)plate dna (cid:272)o(cid:373)pli(cid:373)e(cid:374)tar(cid:455) (cid:272)op(cid:455, different species have different telomere sequences. Left artificially made chromosomes w/ long chromosomes. Initially all chromosomes have long telomeres: after a few cell divisions the telomeres get shorter, after few more divisions, telomeres go back to normal, cell controls the telomere length, right artificially made chromosomes w/ short chromosomes.