GENE 320 Lecture Notes - Lecture 11: Okazaki Fragments, Phosphodiester Bond, Reca
Document Summary
Parental strands separate and combine with a newly synthesized complementary strand. Dispersive (wrong) mixture of old and newly synthesized dna. Bacterial chromosome replication origin of replication (ori) - site of replication, helix is unwound, creating replication fork. Replication is bidirectional; therefore, there are two replication forks. *both start from rna primer* opposite of the replication fork. 400 molecules of polymerase/cell removes primers on lagging strand. Polymerase switching occurs once the primer is in place. Polymerases are replaced when another polymerase is needed for a particular function. Dna gyrase helps loosen the dna when supercoiled. Single stranded binding proteins - prevents the nucleotides from snapping together when forming hydrogen bonds. Dna ligase catalyzes formation of phosphodiester bonds catalyzes formation of phosphodiester bonds seals nicks and joins fragments. Dna polymerase exonuclease activity of 3-5" allows for the excising of nucleotides - removal of errors that may be hazardous to the organisms development.
