BIOL 1F90 Lecture Notes - Lecture 28: Helicase, Dna Ligase, Topoisomerase
21 Jan 2016
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Document Summary
As synthesis of both strands nears completion. Rna primers will be removed by a special dna polymerase. Dna ligase will join adjacent dna fragments and filled in with dna. All the rna is eaten out and all the fragments are extended and attached to each other. Dna helicase (twist it apart- binds one and pushes, pulls apart and spins, dna is spinning at a great speed, 10000rpms or more ) Binds to dna and travels 5" to 3" using atp to separate strand and move fork forward. Relieves additional coiling ahead of replication fork. Keep parental strands open to act as templates. Deoxynuceloside triphosphates are used by the enzyme. Dna polymerase breaks a covalent bond to release pyrophosphate (2 phosphate groups) The remaining deoxynucleoside monophosphate is covalently linked to the growing strand of dna. Makes an rna primer at the origin.
