1. Why does DNA have to replicate?

2. Why does DNA have to replicate?
Without DNA replication, our cells would not be able to divide properly.
With cell division, we cannot grow, develop, or change

3. When does DNA replicate?
DNA replicates during the ‘S’ phase of interphase
Replication during this time, ensures that the cell will divide properly

4. What is the result of DNA replication?
What would we expect to happen by the end of DNA replication?

5. What is the result of DNA replication?
New cells will always contain the exact same sequence of DNA as the original cells
When DNA replication occurs, we end up with two complete strands of the same DNA

6. How does DNA replicate? Enzymes assist the DNA in replicating
Enzymes are molecules that help speed up certain reactions

7. Enzymes of DNA replication
1. Helicase- an enzyme that unzips DNA strands by breaking the hydrogen bonds between nitrogen bases

9. Enzymes of DNA replication
2. DNA polymerase- an enzyme that adds new nitrogen bases to the DNA strands left open by helicase

10. Enzymes of DNA replication
3. Primase- allows DNA replication to start in the proper place
Primase allows DNA polymerase to begin replicating the base pairs

11. Replication Steps
-Step 1: helicase unzips the DNA strand by breaking the hydrogen bonds. This creates two new “template” strands
-Step 2: DNA polymerase adds new nitrogen bases to the template strands. It adds adenine to thymine and cytosine to guanine and vice versa.

12. Does DNA just replicate in one direction?
That would take forever, so DNA can replicate in two directions.
Where DNA splits is called a replication fork.

13. Semi-Conservative DNA replicated is called semi-conservative
This means that part of the formed DNA strand is old and part of it is new.
Semi means partly, and conservative means to conserve or preserve (preserving the old strand)

14. What would be the complementary DNA strand?
DNA 5’-CGTATG-3’

15. What would be the complementary DNA strand?
DNA 5’-CGTATG-3’
DNA 3’-GCATAC-5’

16. DNA Mutations
Predict how DNA mutations would occur

17. Review
Are mutations always bad?
Give examples of each

18. Frameshift Inserting or deleting more than one nucleotide
Causes the wrong protein to be made
Using your template DNA strand, write an example of a frameshift mutation in your notes

19. Frameshift Mutations

20. Point Mutation A single nucleotide change in the DNA sequence
Create an example of a point mutation in your notes

21. Genetic Disease Project
You will create a poster that summarizes a specific genetic disease with an emphasis on the cause (type of mutation)
10 Points: Summarize symptoms and treatment
10 Points: Explain the type of mutation and the cause
10 Points: Show diagram or pictures that represent the disease
10 Points: Evaluate the quality of life with the disease
Diseases to choose from: Sickle cell, Tay Sachs, Huntington’s disease, Breast cancer-brca1, Downs syndrome, Colorblindness, Hemophilia, Cystic fibrosis, Heart disease, Hypertension, Obesity

22. Exit Ticket
In general, which type of mutation would you expect to be more harmful: point mutation or frameshift mutation? Explain your reasoning.