1. DNA Replication
By: Lexi Zanaglio

2. Double Helix Strand
A
T
T
A
G
C
C
G
A
T
Key:
T
A
Phosphate
Sugar
G
C
A
A
G
T
T
Thymine
G
C
Adenine
Guanine
C
Cytosine

3. 5”
3”
A
T
T
A
G
C
C
G
A
Splitting of the Double Helix
T
In the Origin of Replication,
Helicase unzips the DNA
strand.
=Helicase
Key:
T
A
Phosphate
Sugar
G
C
A
T
G
5”
A
T
3”
Thymine
G
C
Adenine
Guanine
C
Cytosine

4. 5”
3”
A
A
G
C
C
G
A
T
T
Polymerase III can only
add nucleotides a certain
way. The lagging strand
goes the opposite way
that it needs to go for
polymerase III to add
nucleotides.
T
T
Polymerase III adds
nucleotides to the existing
strands. The leading strand is
added continually, while the
lagging strand is more
complex.
A
= Polymerase III
G
C
C
G
C
G
3”
5”
A
T
T

5. 5”
3”
Primase has to
add RNA primer to
the DNA strand so
polymerase III can
start synthesizing
nucleotides.
Then polymerase
III makes
nucleotides until it
reaches the next
section of RNA
primer these are
called Okazaki
fragments.
Then
polymerase I
replaces the
RNA with DNA.
Then ligase
forms
phosphodiester
bonds.
5”
A
A
G
C
C
C
G
A
A
T
T
G
T
G
C
T
T
G
A
T
A
C
C
G
3”
A
T
T

6. 5”
3”
A
A
T
T
A
T
A
G
C
G
C
C
G
C
G
A
T
A
T
T
A
T
A
G
C
G
C
C
5”
T
G
C
G
A
T
A
Two exact copies of DNA are created
T
3”

7. Mutations
DNA replication can have problems along the way, is the
process is messed up or goes wrong there will be a
mutation on the gene, an organism can only have up to 3
mutations to continue living.

8. Telomeres
Is the compound structure at the end of a chromosome
within a eukaryotic cell.
It keeps other chromosomes within the cell from attracting
to each other.

9. Okazaki Fragments
Okazaki fragments are short DNA fragments that are
formed on the lagging strand in DNA replication.
Polymerase III makes nucleotides until it reaches the next
section of RNA primer and they are called Okazaki
fragments.

10. DNA Ligase
DNA ligase joins the DNA strands together by forming a
phosphodiester bond.

11. Telomerase
An enzyme that adds nucleotides to the
telomeres, especially in cancer cells.
They are found at the end of eukaryotic chromosomes.

12. Cancer
Is a disease caused by abnormal cells, dividing
uncontrollably in a part of the body.
Cancer is one of the top 3 killers of Americans, and is a
very serious disease.

13. Transplanted cells
Is when cells are taken from another person or place in
your body and put into your or someone else's body.
There are multiple different types of transplanted cells, like
for example stem cells can be transplanted.

14. Cloning
a cell or organism that is genetically identical to the
individual from the specimen it was taken from.

15. Aging
The process of someone growing older and eventually
becoming elderly.
This is a gradual change in an organism that leads to
increased risk of weakness, disease, and death. It takes
place in a cell, an organ, or the total organism over the
entire adult life span of any living thing.