13.2 Replication of DNA I. DNA Copied A. Replication – creating new DNA copy 1. DNA must unwind a. DNA helicases – enzymes that unzip DNA 2. Replication fork – where DNA separates and copies itself 3. DNA polymerase moves along both sides of unzipped DNA a. creates 2 new DNA strands b. continues to copy until signaled to stop c. does contain a proofreading feature that allows to backspace and correct errors

4. DNA is not copied from one end to other end a. this would take 16 days to copy a single DNA molecule of a fruit fly b. instead it only takes 3 minutes with thousands of replication bubbles occurring at once c. in humans it would take 33 days to replicate a chromosome d. instead it takes only around 8 hours

II. Prokaryotic & Eukaryotic Replication A. In prokaryotes replication starts at a single site & in eukaryotes it starts in thousands of sites at once