2. 1 3 2 During DNA replication (or copying), the parent DNA molecule unwinds and unzips. Then each old strand serves as a template for a new strand. Quiz yourself: In which phase of the cell cycle does DNA replication occur?

3. In 1958, Matthew Meselson and Franklin Stahl discovered that DNA replication is semiconservative. Each new double helix contains a new strand and an old strand.

4. Prokaryotes have a single, circular chromosome.

5. 5’ vs. 3’ Carbons in the deoxyribose sugar are numbered for identification.

6. DNA replication proceeds from 5’ end to 3’ end.

7. *Unwinds the DNA double helix, so DNA polymerase can get better access to the template strands. *attaches new nucleotides Direction of replication is always 5’ to 3’. Okazaki fragments are short pieces of DNA on the new strand, specifically the “lagging strand”. They will later be joined by an enzyme called DNA ligase into a complete strand.