1. DNA Replication
AP Biology
Ch 16.2

2. Remember… You started as one cell with one set of DNA
Now you are trillions of cells!
Each cell has the same DNA

3. How does each cell get DNA?
DNA Replication
Process by which DNA is copied
Occurs in all living organisms
Many enzymes are used!

4. DNA structure

5. DNA structure

6. Step 1: DNA Replication Start with one complete strand of DNA
Template Strand
Parent Strand

7. Step 2: DNA Replication
Topoisomerase
unwinds DNA

8. Step 3: DNA Replication
Helicase
Unzips template strand at H bonds

9. Step 4: DNA Replication
Replication fork forms

10. Step 5: DNA Replication DNA polymerase Finds starter sequence
Adds free DNA nucleotides
Checks the sequence
Makes repairs

11. Step 6: Okazaki Fragments
DNA is antiparallel
One strand of DNA:
synthesized continuously
The other strand of DNA:
is synthesized in segments (O.F.)

12. Step 7: DNA Replication
DNA Ligase
Connects Okazaki fragments

13. Step 8: DNA Replication Two identical strands of DNA are formed
Each strand has a parent and daughter strand

14. The Others

15. Replication Animations
PBS:
St. Olaf: