1. ENZYMES

2. They lower or reduce the activation energy of the chemical reaction.
What are enzymes?
Enzymes are proteins that act as biological catalysts. Their job is to speed up chemical reactions that take place in cells.
How do they help speed up chemical reactions?
They lower or reduce the activation energy of the chemical reaction.

3. Chemical reactions need a certain amount of energy to get started, this energy is called the activation energy.

5. Why are enzymes known as “catalysts”
Why are enzymes known as “catalysts”? A catalyst is a substance that speeds up the rate of a chemical reaction. Since enzymes speed up chemical reactions they are known as “catalysts”.

6. Why are enzymes important?
All chemical reactions in living organisms require enzymes to work.
Synthesis Enzymes
Build molecules
Dehydration Synthesis
Digestive Enzymes
Break down molecules
Hydrolysis
enzyme +
enzyme
We can’t live
without enzymes! +

7. Steps of Enzyme Activity
Substrate binds
to enzyme
Enzyme
Enzyme
Enzyme 1. 2. 3.
Enzyme is unchanged and free to be reused in another chemical reaction.

8. Remember: Enzymes can help build or break down molecules.
Dehydration
Synthesis
(“building”)
REACTION
Hydrolysis
(“break down”)
REACTION

9. “Lock & Key” Model Shows Enzyme Specificity

10. “Denature” means to change the shape of an enzyme
“Denature” means to change the shape of an enzyme. When this happens the enzyme does not function or work properly.
Temperature pH
Salinity

11. Factors that affect Enzyme Activity: 1. temperature 3
Factors that affect Enzyme Activity: 1. temperature enzyme & substrate 2. pH level concentration
X = optimal temperature
X = optimal pH X X
Enzyme concentration