DNA replication begins with a single strand of DNA wrapped in a double helix shape. An enzyme called DNA helicase unzips the strand to expose the bases. The bases pair up according to specific rules, with adenine attaching to thymine and guanine attaching to cytosine. DNA polymerase then replicates the leading strand continuously, but the lagging strand requires primers to start replication in fragments called Okazaki fragments that are later joined together. This process makes two new, identical strands of DNA from the original single strand.
2. DNA Replication starts out with a single
strand of DNA in the Double Helix shape
(Basically, a ladder being wrapped
around).
3. In DNA, each rung of the ladder
is two nitrogenous bases
attached to each other and a
sugar phosphate backbone.
Each base can only attach
to a specific type of base.
Adenine attaches to Thymine (and
Vice Versa) and Guanine attaches
to Cytosine (and Vice Versa.)
Black Circles- Sugar/Phosphate
Backbone
Red- Adenine
Blue- Thymine
Green- Guanine
Yellow- Cytosine
4. 3’
5’
An enzyme called
DNA Helicase unzips
the strand of DNA
In order to create
two identical strands of
DNA.
d
d
d
d
d
d
-DNA Helicase
d
d
d
3’
5’
5. The leading strand of DNA attaches itself to a copy of the lagging
strand made by DNA polymerase.
6. The lagging strand of DNA needs to use Polymerase to replicate. However, the
Polymerase requires DNA Primer to be place onto the strand before it can
Replicate the strand.
DNA Primer
The strands between the primer are called
Okazaki Fragments.
7. Now that the Polymerase can replicate the DNA strand, it completes the lagging
Strand, making two new strands of DNA from one.
