How does it replicate?1. Helicase: is an enzyme that separates the two DNA

strands by breaking the hydrogen bonds in the middle.

DNA Replication

2. DNA Polymerase: adds nucleotides to the single stranded DNA according to base pairing rules.• DNA polymerase only moves in one direction,

from 5’ to 3‘for the new strand formation

DNA Replication

• Leading Strand: the 5’ to 3’ strand, polymerase can add nucleotides to make one continuous strand.

• Lagging Strand: the 3’ to 5’ strand, polymerase moves in the opposite direction. – Polymerase forms short segments of DNA called

Okazaki fragments.

DNA Replication

3. Ligase: uses covalent bonds to connect Okazaki fragments together in the lagging strand.

DNA Replication

1. The double helix unzips with helicase down the middle as base pairs separate.

2. DNA polymerase adds the correct complimentary nucleotide to each exposed strand. Ligase connects all fragments.

3. A complimentary strand is created for each original strand in the double helix.

DNA Replication Summary

Make sure you are studying the Scientists and their experiments.

A.AveryB.GriffithC.Hershey and ChaseD.ChargaffE.FranklinF. WatsonG. Crick