1. Warm-Up
Write down everything you know about enzymes (what are they made of, what do they do, what affects them, why are they important, etc.)

2. Objective
You will be able to explain what an enzyme is and what factors effect it

3. Enzymes
GT Biology

4. Enzymes are proteins that:
Increase the rate of reactions
Reduce the amount of energy needed for a reaction to start (activation energy)
This is called a CATALYST.

5. Enzymes
Are only needed in small amounts and can be reused (they do not change)
Can be denatured (broken down and permanently altered) if the conditions aren’t correct.
Example:
-cooking an egg
-high fevers cause brain damage
-vinegar curdles milk

6. Naming Enzymes Example:
They end in “ase” (lipase, polymerase, catalase)
They are named according to the substrate they react with.
Example:
Lactase is the enzyme that breaks down lactose (milk sugar).

7. Enzyme Reactions
An enzyme works with a substrate (another name for a reactant in a chemical reaction) to either…
a. Build molecules
b. Break molecules apart

8. How Enzymes Work Active Site
Active site – part of the enzyme where the substrate “fits”.
Substrate
Enzyme
Active Site

9. Enzyme-Substrate Complex
This is what is formed when the enzyme and the substrate join together.
Substrate
Enzyme

10. Enzyme-Substrate Complex Formation Models
Lock and Key Model:
an enzyme will only work on one type of substrate.
“One enzyme One substrate”
Example:
-Protease breaks down protein.

11. Enzyme-Substrate Complex Formation Models
Induced-fit model
The enzyme and substrate change shape slightly to fit tightly together and react.

13. Factors That Affect Enzyme Action
Amount of Substrate
Substrate runs out
The reaction steadily increases until the substrate runs out

14. Factors That Affect Enzyme ActionpH
Different enzymes work better at different pHs.
The wrong pH will cause denaturation
(Ex: lemon juice in fruit salad)

15. Factors That Affect Enzyme Action
Temperature
Most enzymes work best at 37o C (body temperature)
Too cool – enzyme slows
Too hot – enzyme denature
(Ex: a Fever or using a refrigerator)

16. Coenzymes
organic substances (vitamins) needed by some enzymes in order to function.

17. Enzyme Animation
ons/model.swf

18. Enzyme Animation
What do you predict will happen when each factor is changed?
What did happen when each factor was changed?
Why is it important that enzyme activity increases or decreases with a change in each factor?