1. DNA Replication – the process

2. DNA replication When a cell divides the DNA has to copy itself (m&m!)
Because the DNA contains important information the DNA has to copy itself without making mistakes.

3. DNA replication - eukaryote
The DNA strand starts by ‘unzipping’.
The two strands break apart at the weak hydrogen bonds. The enzyme helicase does this.
Nucleotide bases now attach to the unzipped strands to make new strands.

4. DNA replication Animation
Nucleotides are assembled in opposite directions from the 5’ to the 3’ by the enzyme DNA polymerase.
Replication forks move until whole strand is copied.
New strands rewind – semiconservative.

5. DNA replication Another animation Okazaki fragments
Because DNA antiparallel one side can be continously copied and the other is copied in fragments. The fragments are turned into one strand by the enzyme ligase.

6. DNA replication
Error rate in copying of one in base pairs but there is a system of ‘proof reading’.