Origins of replication- start cite of DNA replication Replication fork- where the new strand of DNA elongates DNA Polymerase- Elongates the DNA, adds the new nucleotides Antiparallel- 5’ 3’, 5’ end has the phosphate and 3’ end has the sugar (OH) Adding of nucleotides always goes 5’ 3’ always adding to the 3’ end Leading strand- non segmented- moves towards the replication fork Lagging strand- segmented (Okazaki fragments) moves away from the replication fork

DNA Polymerase III- synthesizes DNA together DNA ligase- joins the Okazaki fragments together Primer- starts as RNA, the initial nucleotide to start the replication, this later is removed & made into DNA Only one primer is needed for the leading strand For every Okazaki fragment a primer is needed DNA Polymerase I- replaces the RNA primer with the DNA version, then DNA ligase comes & hooks the pieces together Helicase- unwinds the DNA strand Topoisomerase- relieves the strain put on the DNA strand from being unwound

Single – strand binding protein (ssb)- binds to the unpaired DNA strands to stabilize them Nucleotide Excision repair- If there is a segment that is damaged or written wrong it will be cut out by a nuclease (DNA cutting enzyme) then is filled back in by a DNA polymerase and ligase Telomers- don’t contain genes, they are at the end of the DNA strands, because DNA over time gets smaller at the ends these telomers are used to cushion this shortening Telomerase- catalyzes the lengthening of the telomers