Genetics- replication for eukaryotes

Genetics- replication for eukaryotes - Replication for...

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Prokaryotes: Causes DNA to bend an change shape and separate the AT rich regions AT rich regions separate more easily because they only have 2 hydrogen bonds instead of 3 DNAa proteins bind to this sequence and other DNAa proteins and various DNAa boxes One origin Origin of replication : 1.) DNAa Box: sequence on DNA, does not make the protein Also known and DNAb They separate the strands in two directions, creating 2 replication forks 2.) Helicase : 2 bind to origin Is ahead of the fork 3.) Topoisomerase : Solves the problem of tension by winding and unwinding DNA by breaking phosphodiester bonds, removing twist, then reforming phosphodiester bonds Adds 5' to 3' Has low processivity 4.) Primase: makes primer to provide 3' hydroxyl so DNA Polymerase III can attach nucleotides to the 3' end 5'-3' activity, adds nucleotides 1/1000 mistake When it moves to the next nucleotide, it checks the shape of the one behind it If a pyramidine bonds to a purine the shape would be too wide because they would repel each other Proofreads 3' to 5' Exo because it can only break the phosphodiester bond at the 3' end Has exonuclease activity in 3' to 5' direction DNA Poly III is slow at getting started to not having to repeat this increases efficiency and speed Has increased accuracy because there are no interruptions High processivity because of the beta clamp 5.) DNA Polymerase III : Removesprimer in 5'-3' (exonuclease activity) [Can go 3' to 5' to proofread and remove mistakes (3' to 5' exonuclease activity) No clamp Low processivity so it falls off after a few nucleotides Does not know the difference between RNA and DNA Breaks hydrogen bonds 6.) DNA Polymerase I : Connects phosphodiester bonds on both sides of Okazaki fragments Functions only on the right side 7.) Ligase : Lagging strand: away from the fork Replication for Prokaryotes Friday, September 11, 2009 12:07 PM Genetics Page 1
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Separates the DNA strands 1.) Helicase : Solves the problem of tension by winding and unwinding DNA 2.) Topoisomerase : Addsprimer 5' to 3' RNA polymerase activity Continues on a little after primer adding DNA nucleotides Can flip over and do DNA Polymerase activity It has low processivity though so it falls off soon Cannot proofread 3.) DNA Polymerase Alpha : 5' to 3' DNA polymerase activity 3' to 5' proofreading and exonuclease activity clamp High processivity Also fills in gap that exonuclease leaves 4.) DNA polymerase Delta : Removes primer 5' to 3' activity ONLY REMOVES NUCLOTIDES Binds while delta waits to fill in new gap with DNA 5.) Exonuclease : Fixes the gap between nucleotides by making a covalent phosphodiester bond 6.) Ligase : Makes it all the way to the end 5' to 3' towards fork Leading strand : Does not make it all the way to the end
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This note was uploaded on 02/02/2010 for the course BIO 50415 taught by Professor Finklea during the Fall '09 term at University of Texas-Tyler.

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Genetics- replication for eukaryotes - Replication for...

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