LIFE 102 Lecture Notes - Lecture 25: Dna Replication, Primase, Polynucleotide
Document Summary
A y-shaped region where new dna strands are elongating. Enzymes that untwist the double helix at the replication forks. Binds to and stabilizes single-stranded dna until it can be used as a template. Corrects overwinding ahead of replication forks by breaking, swiveling, and rejoining dna strands. Starts an rna chain from scratch and adds rna nucleotides one at a time using the parental dna as a template. *dna polymerases cannot initiate synthesis of a polynucleotide. *the initial nucleotide strand is a short rna primer. Enzymes that catalyze the elongation of new dna at a replication fork. *most dna polymerases require a primer and a dna template strand. *the rate of elongation is about 500 nucleotides per second in bacteria and 50 per second in human cells. *each nucleotide that is added to a growing dna strand is a nucleoside triphosphate datp. Is similar to the atp of energy metabolism.
