AP Biology / Unit 6: Gene Expression and Regulation
6.2 DNA Replication
Notes
Replication is semiconservative: each new molecule has one old strand and one new strand.
- Helicase unwinds; primase adds RNA primers; DNA polymerase adds nucleotides only 5′ → 3′.
- Leading strand: continuous. Lagging strand: Okazaki fragments joined by ligase.
Practice
DNA polymerase builds new DNA in which direction?
It adds to the 3′ end.
Okazaki fragments are on the:
Made discontinuously.
Semiconservative means each new DNA molecule:
Meselson and Stahl showed this.
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