dna replication perryd
TRANSCRIPT
5’
3’ 5’
3’
Adenine
Thymine
Cytosine
Guanine
Deoxyribo Sugar
Phosphate
DNA Helicase
DNA Helicase begins to split the DNA. Single strand proteins come in to hold the DNA stable
Single strand Protein
DNA Helicase continues to to split the DNA as more Single strand proteins come in.
DNA Helicase continues to to split the DNA as more Single strand proteins come in.
5’3’
3’5’
DNA Polymerase III starts putting new nitrogen bases onto the leading strand. It can only synthesize from 3’ to 5’.
5’
3’
3’
5’
Polymerase III continuously synthesizes the other half the the leading strand.
5’
3’
3’Polymerase III continuously synthesizes the other half the the leading strand.
5’
5’
3’
3’Polymerase III continuously synthesizes the other half the the leading strand.
5’
5’
3’
3’ Now the leading strand is done and it is time to start the lagging strand.
5’
3’
5’
Because Polymerase III cannot synthesize from 5’ to 3’, a RNA primer is made by Primase so Polymerase III can start on it.
RNA Primer
Primase
3’
5’
These fragments of DNA are called Okazaki fragments.
3’
5’
Polymerase III starts on the RNA primer and sets the bases towards the 5’.
3’
5’
Polymerase III starts on the RNA primer and sets the bases towards the 5’.
3’
5’
Polymerase III starts on the RNA primer and sets the bases towards the 5’.
3’
5’
Polymerase I turns the RNA primers into phosphates.
Polymerase I
Now there are two new DNA helixes.