BIOL239 Lecture : DNA Replication Goes through two steps initiation and elongation, roles of enzymes, telomeres and cancer.
Document Summary
New double helix consists of one parent strand and one daughter strand. Performed studies with isotopic composition of nucleotides incorporated into daughter dna strands. Region of as and ts (two h bonds, easier to break) Dna helicase pulls strands apart and unwinds them. Single stranded binding proteins bind to bubble, and keep it open so that enzymes can come in. Dna primase bring in rna primers so polymerase has something to add on to. ** dna polymerase needs a 3" hydroxyl to add nucleotides to. Dna ligase catalyzes formation of phosphodiester bonds between 5" and 3" ends. Three activities of dna polymerase: 5" to 3" synthesizing, 3" to 5" proofreading (backwards on new strand, 5" to 3" primer degradation. Eukaryotes" chromosomes are very long, so they have several replication bubbles and several site of replication occurring at once. Every time dna is replicated, information is lost off the ends (telomeres get shorter, they absorb the loss).