8 3 DNA Replication KEY CONCEPT DNA replication

8. 3 DNA Replication KEY CONCEPT DNA replication copies the genetic information of a cell.

8. 3 DNA Replication In replication, the DNA is copied during the cell cycle • DNA is replicated during the S (synthesis) stage of interphase Overview: • A single strand of DNA serves as a template for a new strand. • The rules of base pairing direct replication. – A pairs with T – C pairs with G • Each body cell gets a complete set of identical DNA.

8. 3 DNA Replication Proteins carry out the process of replication. • DNA serves only as a template…enzymes and other proteins do the actual work of replication. 1. Enzymes unzip the double helix in two directions at the same time. 2. Free-floating nucleotides pair with the exposed bases on the template strand (and they form hydrogen bonds here). 2. nucleotide 1. Sugar Phosphate Backbone The DNA molecule unzips in both directions.

8. 3 DNA Replication 3. DNA polymerase enzymes bond the new nucleotides together to form the double helix. 4. new strand 2. nucleotide 3. DNA polymerase

8. 3 DNA Replication The end result: 4. Two new molecules of DNA identical to the original molecule result; each with an original and new strand. • DNA replication is semiconservative. original strand Two molecules of DNA new strand

8. 3 DNA Replication is fast and accurate. • DNA replication starts at many points in eukaryotic chromosomes. There are many origins of replication in eukaryotic chromosomes. • DNA polymerases can find and correct errors.