BIOL 2020 Lecture Notes - Lecture 12: Inverted Repeat, Helicase, Guanine
29 Apr 2016
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Document Summary
Dna polymerase requires: mg2+ as a cofactor, dntps (datp, dgtp, dctp, dutp, a template, a primer. Review: initiation of dna replication in prokaryotes: a helicase binds to the origin of replication, the helices unwinds dna creating two replication forks, a dna gyrase helps relieve the tension created in the double stranded dna. Recall: dna polymerases require a primer with a free 3" oh. Primase is an enzyme that makes rna primers (4-10 nucleotides long) Every okazaki fragment requires a new rna primer. Dnapoly1 replaces rna primers with dna in blank direction. As dnapoly3 extends the primers time they encounter the next primer, dna poly1 replaces rna primers with dna but doesn"t seal the two ends. Lagging strand is synthesized in 3" to 5" direction while leading strand is synthesized in 5" to 3" direction. Main types of damage: mismatches (non-normal base pairings that occur, base modi cations (chemical structure of base rearranges; causes mismatches.
