1. The effect of pH on a certain enzyme is shown in the graph below.
At what pH is the rate of enzyme action optimal?
acidic (3) neutral
(2) basic (4) below normal

2. DNA holds instructions for making proteins and enzymes
DNA holds instructions for making proteins and enzymes. What happens if the instructions change?

3. DNA mutation Change of RNA Different amino acids Altered protein or enzyme

4. Are altered proteins and enzymes good or bad?
It depends!

5. Changes to enzymes and proteins are usually bad (lethal).

6. Changes to enzymes and proteins are usually bad (lethal).
Occasionally mutations make a protein or enzyme work better in a certain situation.

7. What if the change causes the enzyme to work at a different pH?

8. What if the change causes the enzyme to work at a different pH?

9. Shape is important for enzymes and proteins.
Shape change may cause function change. This may be positive or negative depending upon the situation.

10. What if the change makes a plant require less water
What if the change makes an animal’s fur thicker
…and there is an ice age?
What if the change makes a plant require less water
…and there is a drought?
What if the change makes your red blood cells hard and thick

11. Sickle Cell Anemia

12. Sickle Cell Anemia
Is Sickle Cell Anemia a good thing?

13. Malaria
627,000 deaths in 2012 (CDC). 2nd leading infectious disease in Africa. Occurs where 3.2 billion people live.
Anopheles sp.

14. Sickle cell developed in areas where malaria became common.

15. Sickle Cell Anemia
What if the change makes your red blood cells hard and thick
…and there is a disease that
cannot destroy them?

16. “Sickle” and hard to destroy.
“Normal” and easy to destroy.
“Sickle” and hard to destroy.
Sickle Cell Anemia is awful, but having SOME sickled cells (Sickle cell trait) helps you to survive malaria infection!