The document describes the process of DNA replication. It begins with DNA helicase unwinding the double helix structure and breaking the hydrogen bonds between nucleotide base pairs. On the leading strand, DNA polymerase continuously adds nucleotides to form the new strand in the 5' to 3' direction as the replication fork moves away. On the lagging strand, DNA polymerase forms Okazaki fragments in the opposite direction that are later joined by DNA ligase. DNA primase synthesizes RNA primers to initiate DNA replication.

1. DNA Replication Model
Nick Constant

2. 5’
3’
This is a DNA molecule. On each side in this
example, there are 9 nucleotides. A
nucleotide is made up of a phosphate, a
sugar, and a base. The four examples of
bases are adenine, thymine, cytosine and
guanine. Adenine and thymine are always
paired and cytosine and guanine are paired.
To replicate, the hydrogen bond between
the bases much be split for each pair. DNA
replication occurs during the S stage of
mitosis in the nucleus.
Key:
- Adenine
- Guanine
- Thymine
- Phosphate
- Cytosine
- Sugar
- DNA Helicase
3’
5’

3. To replicate, the helicase unwinds of DNA
and the hydrogen bonds between the bases
are broken.
Key:
- Adenine
- Guanine
- Thymine
- Phosphate
- Cytosine
- Sugar
- DNA Helicase

4. To replicate, the helicase unwinds of DNA
and the hydrogen bonds between the bases
are broken.
Key:
- Adenine
- Guanine
- Thymine
- Phosphate
- Cytosine
- Sugar
- DNA Helicase

5. To replicate, the helicase unwinds of DNA
and the hydrogen bonds between the bases
are broken.
Key:
- Adenine
- Guanine
- Thymine
- Phosphate
- Cytosine
- Sugar
- DNA Helicase

6. To replicate, the helicase unwinds of DNA
and the hydrogen bonds between the bases
are broken.
Key:
- Adenine
- Guanine
- Thymine
- Phosphate
- Cytosine
- Sugar
- DNA Helicase

7. To replicate, the helicase unwinds of DNA
and the hydrogen bonds between the bases
are broken.
Key:
- Adenine
- Guanine
- Thymine
- Phosphate
- Cytosine
- Sugar
- DNA Helicase

8. To replicate, the helicase unwinds of DNA
and the hydrogen bonds between the bases
are broken.
Key:
- Adenine
- Guanine
- Thymine
- Phosphate
- Cytosine
- Sugar
- DNA Helicase

9. To replicate, the helicase unwinds of DNA
and the hydrogen bonds between the bases
are broken.
Key:
- Adenine
- Guanine
- Thymine
- Phosphate
- Cytosine
- Sugar
- DNA Helicase

10. To replicate, the helicase unwinds of DNA
and the hydrogen bonds between the bases
are broken.
Key:
- Adenine
- Guanine
- Thymine
- Phosphate
- Cytosine
- Sugar
- DNA Helicase

11. To replicate, the helicase unwinds of DNA
and the hydrogen bonds between the bases
are broken.
Key:
- Adenine
- Guanine
- Thymine
- Phosphate
- Cytosine
- Sugar
- DNA Helicase

12. To replicate, the helicase unwinds of DNA
and the hydrogen bonds between the bases
are broken.
Key:
- Adenine
- Guanine
- Thymine
- Phosphate
- Cytosine
- Sugar
- DNA Helicase

13. To replicate, the helicase unwinds of DNA
and the hydrogen bonds between the bases
are broken.
Leading
Strand
Lagging
Strand
Key:
- Adenine
- Guanine
- Thymine
- Phosphate
- Cytosine
- Sugar
- DNA Helicase

14. To replicate, the helicase unwinds of DNA
and the hydrogen bonds between the bases
are broken.
Key:
- Adenine
- Guanine
- Thymine
- Phosphate
- Cytosine
- Sugar
- DNA Helicase

15. To replicate, the helicase unwinds of DNA
and the hydrogen bonds between the bases
are broken.
Key:
- Adenine
- Guanine
- Thymine
- Phosphate
- Cytosine
- Sugar
- DNA Helicase

16. To replicate, the helicase unwinds of DNA
and the hydrogen bonds between the bases
are broken.
Key:
- Adenine
- Guanine
- Thymine
- Phosphate
- Cytosine
- Sugar
- DNA Helicase

17. To replicate, the helicase unwinds of DNA
and the hydrogen bonds between the bases
are broken.
Key:
- Adenine
- Guanine
- Thymine
- Phosphate
- Cytosine
- Sugar
- DNA Helicase

18. To replicate, the helicase unwinds of DNA
and the hydrogen bonds between the bases
are broken.
Key:
- Adenine
- Guanine
- Thymine
- Phosphate
- Cytosine
- Sugar
- DNA Helicase

19. To replicate, the helicase unwinds of DNA
and the hydrogen bonds between the bases
are broken.
Key:
- Adenine
- Guanine
- Thymine
- Phosphate
- Cytosine
- Sugar
- DNA Helicase

20. To replicate, the helicase unwinds of
DNA and the hydrogen bonds between
the bases are broken.
Key:
- Adenine
- Guanine
- Thymine
- Phosphate
- Cytosine
- Sugar
- DNA Helicase

21. To replicate, the helicase
unwinds of DNA and the
hydrogen bonds between the
bases are broken.
Key:
- Adenine
- Guanine
- Thymine
- Phosphate
- Cytosine
- Sugar
- DNA Helicase

22. To replicate, the helicase
unwinds of DNA and the
hydrogen bonds between
the bases are broken.
Key:
- Adenine
- Guanine
- Thymine
- Phosphate
- Cytosine
- Sugar
- DNA Helicase

23. First, on the leading strand, DNA
polymerase III adds the five
phosphate end of a free floating
nucleotide to the exposed 3’ OH
end on the single stranded DNA
continuously. This elongates
toward the replication fork. On the
lagging strand, DNA polymerase III
forms Okazaki fragments
discontinuously with the help of
other fragments. This elongates
away from the replication fork.
Key:
- Adenine
- Guanine
- Thymine
- Phosphate
- Cytosine
- Sugar
- DNA Helicase

24. First, on the leading strand, DNA
polymerase III adds the five
phosphate end of a free floating
nucleotide to the exposed 3’ OH
end on the single stranded DNA
continuously. This elongates
toward the replication fork. On the
lagging strand, DNA polymerase III
forms Okazaki fragments
discontinuously with the help of
other fragments. This elongates
away from the replication fork.
Key:
- Adenine
- Guanine
- Thymine
- Phosphate
- Cytosine
- Sugar
- DNA Helicase

25. First, on the leading strand, DNA
polymerase III adds the five
phosphate end of a free floating
nucleotide to the exposed 3’ OH
end on the single stranded DNA
continuously. This elongates
toward the replication fork. On the
lagging strand, DNA polymerase III
forms Okazaki fragments
discontinuously with the help of
other fragments. This elongates
away from the replication fork.
Key:
- Adenine
- Guanine
- Thymine
- Phosphate
- Cytosine
- Sugar
- DNA Helicase

26. First, on the leading strand, DNA
polymerase III adds the five
phosphate end of a free floating
nucleotide to the exposed 3’ OH
end on the single stranded DNA
continuously. This elongates
toward the replication fork. On the
lagging strand, DNA polymerase III
forms Okazaki fragments
discontinuously with the help of
other fragments. This elongates
away from the replication fork.
Key:
- Adenine
- Guanine
- Thymine
- Phosphate
- Cytosine
- Sugar
- DNA Helicase

27. First, on the leading strand, DNA
polymerase III adds the five
phosphate end of a free floating
nucleotide to the exposed 3’ OH
end on the single stranded DNA
continuously. This elongates
toward the replication fork. On the
lagging strand, DNA polymerase III
forms Okazaki fragments
discontinuously with the help of
other fragments. This elongates
away from the replication fork.
Key:
- Adenine
- Guanine
- Thymine
- Phosphate
- Cytosine
- Sugar
- DNA Helicase

28. First, on the leading strand, DNA
polymerase III adds the five
phosphate end of a free floating
nucleotide to the exposed 3’ OH
end on the single stranded DNA
continuously. This elongates
toward the replication fork. On the
lagging strand, DNA polymerase III
forms Okazaki fragments
discontinuously with the help of
other fragments. This elongates
away from the replication fork.
Key:
- Adenine
- Guanine
- Thymine
- Phosphate
- Cytosine
- Sugar
- DNA Helicase

29. First, on the leading strand, DNA
polymerase III adds the five
phosphate end of a free floating
nucleotide to the exposed 3’ OH
end on the single stranded DNA
continuously. This elongates
toward the replication fork. On the
lagging strand, DNA polymerase III
forms Okazaki fragments
discontinuously with the help of
other fragments. This elongates
away from the replication fork.
Key:
- Adenine
- Guanine
- Thymine
- Phosphate
- Cytosine
- Sugar
- DNA Helicase

30. First, on the leading strand, DNA
polymerase III adds the five
phosphate end of a free floating
nucleotide to the exposed 3’ OH
end on the single stranded DNA
continuously. This elongates
toward the replication fork. On the
lagging strand, DNA polymerase III
forms Okazaki fragments
discontinuously with the help of
other fragments. This elongates
away from the replication fork.
Key:
- Adenine
- Guanine
- Thymine
- Phosphate
- Cytosine
- Sugar
- DNA Helicase

31. First, on the leading strand, DNA
polymerase III adds the five
phosphate end of a free floating
nucleotide to the exposed 3’ OH
end on the single stranded DNA
continuously. This elongates
toward the replication fork. On the
lagging strand, DNA polymerase III
forms Okazaki fragments
discontinuously with the help of
other fragments. This elongates
away from the replication fork.
Key:
- Adenine
- Guanine
- Thymine
- Phosphate
- Cytosine
- Sugar
- DNA Helicase

32. First, on the leading strand, DNA
polymerase III adds the five
phosphate end of a free floating
nucleotide to the exposed 3’ OH
end on the single stranded DNA
continuously. This elongates
toward the replication fork. On the
lagging strand, DNA polymerase III
forms Okazaki fragments
discontinuously with the help of
other fragments. This elongates
away from the replication fork.
Key:
Okazaki
Fragments
- Adenine
- Guanine
- Thymine
- Phosphate
- Cytosine
- Sugar
- DNA Helicase

33. 5’
3’
5’
3’
First, on the leading strand, DNA
polymerase III adds the five
phosphate end of a free floating
nucleotide to the exposed 3’ OH
end on the single stranded DNA
continuously. This elongates
toward the replication fork. On the
lagging strand, DNA polymerase III
forms Okazaki fragments
discontinuously with the help of
other fragments. This elongates
away from the replication fork.
Key:
- Adenine
- Guanine
- Thymine
- Phosphate
- Cytosine
- Sugar
- DNA Helicase
3’
5’
3’
5’

34. 5’
3’
5’
3’
DNA Primase creates an RNA
primer, which is then uses to
replicate DNA. DNA ligase “stitches
together” pieces of DNA to form a
longer strand.
Key:
- Adenine
- Guanine
- Thymine
- Phosphate
- Cytosine
- Sugar
- DNA Helicase
3’
5’
3’
5’