1. Bell work 9/11
What is an enzyme?

2. What is the difference between saturated and unsaturated fats?
Bell work 10/24
What is the difference between saturated and unsaturated fats?

3. Enzymes: “Helper” Protein molecules

4. Chemical reactions of life
The process by which atoms or groups of atoms in substances are reorganized into different substances
Chemical bonds are broken and formed

5. Physical vs. Chemical Change
Physical Change
Chemical Change
Alters a substance’s appearance, but not its composition
Alters a substance at the chemical level
Not reversible
Examples?

6. Physical vs. Chemical Change
Physical Change
Chemical Change
Alters a substance’s appearance, but not its composition
Alters a substance at the chemical level
Not reversible

7. How important are enzymes?
Nothing works without enzymes!
All chemical reactions in living organisms require enzymes to work
building molecules
synthesis enzymes
breaking down molecules
digestive enzymes
enzyme +
enzyme
We can’t live without enzymes! +

8. Examples
synthesis
enzyme +
digestion
enzyme +

9. Energy You need ENERGY to start a chemical reaction!
Activation energy- The minimum amount of energy needed for reactants to form products.

10. Enzymes Enzymes are made of proteins Lowers activation energy!!
Complex 3D shape
Lowers activation energy!!
Speed up chemical reactions

11. Enzymes are proteins
Each enzyme is the specific helper to a specific reaction
Each enzyme needs to be the right shape for the job
Enzymes are named for the reaction they help
sucrase breaks down sucrose
proteases breakdown proteins
lipases breakdown lipids
DNA polymerase builds DNA
Oh, I get it!
They end in -ase

12. Enzyme-Substrate Complex
The substance an enzyme acts on is the substrate
Must have the
SAME shape!
Enzyme
Substrate
Joins

13. Active Site Part of enzyme that a substrate molecules fits in Enzyme

14. Product What the enzyme helps produce from the reaction
After the chemical reaction, the product no longer fits in the active site and the reactions stops!
The enzyme can be reused

15. It’s shape that matters!
Lock & Key model
Shape of protein allows enzyme & substrate to fit
Specific enzyme for each specific reaction

16. 2 1 3

17. Enzyme vocabulary Enzyme Substrate Products Active site
helper protein molecule
Substrate
molecule that enzymes work on
Products
what the enzyme helps produce from the reaction
Active site
part of enzyme that substrate molecule fits into

18. Why do apples turn brown?
Apples and many other plant cells have an enzyme called polyphenol oxidase (PPO) that is involved in one step of a process that causes fruit to produce brown pigments called melanins when fruits are exposed to oxygen or when they are bruised through handling. +

19. Factors affecting enzyme reaction
Question: How do the factors of pH and temperature affect enzymatic browning in apples?
Materials available per group:
Water
Lemon juice
Sugar solution (water and sugar)
Hot plates
Tongs
8 apple slices
Paper towels
Beakers (maximum of 3)
*You will have minutes to complete your experiment*
Remember control group and constants

20. Write “Quiz” in planner!
Bell work 9/11
Write “Quiz” in planner!
*Get out pencil, put everything else away (under chair or neatly in middle of table!