4. 3’
5’
A
G
C
T
A
C
G
A
T
T
A
G
DNA Replication occurs during the S
phase (synthesis) of mitosis - which is part
of the interphase.
T
C
-Phosphate
-Deoxyribose
A
C
G
T
3’
A
-Adenine
T
5’
G
C
-Thymine
-Guanine
-Cytosine
5. 3’
5’
A
G
C
T
A
C
G
A
T
T
A
G
DNA Helicase unwinds the doublestranded DNA at the origin of replication
by breaking the hydrogen bonds between
the strands. Helicase starts at an AdenineThymine bond because it has a double
bond where a Guanine-Cytosine has a
triple bond.
T
C
-Phosphate
-Deoxyribose
A
C
-Adenine
G
T
5’
Helicase
3’
G
C
-Thymine
-Guanine
-Cytosine
6. 3’
5’
A
G
C
T
A
C
G
A
T
T
A
G
When DNA is unzipping, single stranded
binding proteins bind to the DNA for
stabilization.
T
C
-Phosphate
-Deoxyribose
A
3’
Helicase
A
T
T
5’
G
C
-Adenine
-Thymine
-Guanine
-Cytosine
7. 3’
5’
A
G
C
T
A
C
G
A
T
T
As DNA Helicase is splitting the DNA
strand, DNA Polymerase III adds the
matching nucleotides to the left side of
the DNA strand since it has the 3’ on the
bottom of the strand. This happens in a
continuous fashion.
T
A
-Phosphate
C
A
3’
Helicase
-Deoxyribose
A
G
T
T
5’
G
C
-Adenine
-Thymine
-Guanine
-Cytosine
8. 3’
5’
A
G
C
T
A
C
G
A
Since the right side as the 5’ end on the
bottom, DNA Primase has to add an RNA
primer. This marks a starting point for
DNA Polymerase II to add the matching
nucleotides on. As the DNA strand
continues to get split, more RNA primers
are added. The space between each RNA
primer is called okazaki fragments. This
process happens discontinuously.
T
T
G
C
A
3’
Helicase
-Phosphate
C
-Deoxyribose
A
G
T
T
5’
G
C
-Adenine
-Thymine
-Guanine
-Cytosine
10. 3’
5’
G
T
C
T
A
T
A
Helicase
A
DNA Ligase forms a phophodiester bond
between the 3’ end of the growing strand
and the 5’ phosphate end in front of it.
This finalizes the connection of okazaki
fragments.
T
A
-Phosphate
G
C
C
G
A
3’
-Deoxyribose
A
T
T
5’
G
C
-Adenine
-Thymine
-Guanine
-Cytosine
19. A
T
A
T
G
C
T
A
C
G
A
T
T
A mutation can occur from errors
in the process of replication or
from unrepaired damage to DNA.
A mutation is a change of the
nucleotide sequence of an
organism.
A
-Phosphate
G
C
C
G
A
-Deoxyribose
A
T
T
G
C
-Adenine
-Thymine
-Guanine
-Cytosine
20. A
G
T
C
A
T
C
G
T
A
C
G
A
T
T
Mutations can cause different
diseases and observable
characteristics. They play a part in
both normal and abnormal
biological processes including
evolution, cancer, and the
development of the immune
system.
A
-Phosphate
G
C
C
G
A
-Deoxyribose
A
T
T
G
C
-Adenine
-Thymine
-Guanine
-Cytosine
