1. Topic: Enzymes Aim: Why are enzymes important to living things?

2. What are enzymes? A protein catalyst Made of proteins
What do enzymes do?
Changes the rate of a chemical reaction.
They speed up metabolic reactions in cells

3. Enzymes are made of proteins
Each enzyme is specific to a reaction
each enzyme needs to be the right shape for the job
Oh, I get it!
They are made
proteins

4. How are enzymes named?
enzymes are named for the reaction they help/after their substrate.
lactase break down lactose
sucrase breaks down sucrose
proteases breakdown proteins
lipases breakdown lipids
DNA polymerase builds DNA
Oh, I get it!
They end in -ase

5. What determines the function of an enzyme? The shape of the enzyme
Lock & Key model
shape of protein allows enzyme & substrate to fit
specific enzyme for each specific reaction

6. 2 1 3

7. Why are enzymes important to living things
Why are enzymes important to living things? Nothing works without enzymes!
all chemical reactions in living organisms require enzymes to work
building molecules
synthesis enzymes
breaking down molecules
digestive enzymes
enzymes speed up reactions
“catalysts”
enzyme +
We can’t live without enzymes!
enzyme +

8. 2 Types of Chemical Reactions controlled by Enzymes
Synthesis Reaction
building molecules
B. Digestion Reaction
breaking down molecules + +

9. Examples Synthesis reaction Digestion reaction enzyme enzyme + +
Making larger molecules from smaller molecules
enzyme +
Digestion reaction
Breaking larger molecules into smaller molecules
enzyme +

10. Do enzymes get used up after they completed their jobs
Do enzymes get used up after they completed their jobs? No,enzymes aren’t used up
Enzymes are not changed by the reaction
used only temporarily
re-used again for the same reaction with other molecules
very little enzyme needed to help in many reactions
substrate
product
active site
enzyme

11. Enzyme vocabulary Enzyme Substrate Products Active site
Biological catalyst that speeds up specific a chemical reaction
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

12. What factors affect enzyme action?
1. Temperature
why? enzyme has to be right shape
2. pH (acids & bases)

13. Factors Affecting Enzyme Activity: 1. Temperature
Effect on rates of enzyme activity
Optimum temperature
The temperature at which enzyme works best.
human enzymes
35°- 40°C (body temp = 37°C)
Raise temperature (boiling)
denature protein = unfold = lose shape
Lower temperature T°
molecules move slower
fewer collisions between enzyme & substrate

14. Temperature 37° Optimum temperature human enzymes
What’s happening here?!
37°
Increasing the temperature denature (destroys) the shape of the protein.
reaction rate
Change shape = useless
temperature

15. Effect of high temperature on enzyme activity
Enzyme works based on their shape.
Over heating denatures (destroys) the shape of the enzyme.
Enzymes no longer work
once the shape is changed.

16. Factors Affecting Enzyme Activity: 2. pH (how acidic something is)
Effect on rates of enzyme activity
changes in pH changes protein shape~ Denatures
most human enzymes = pH 6-8
depends on where in body
pepsin (stomach) = pH 3
trypsin (small intestines) = pH 8

17. pH 1 2 3 4 5 6 7 8 9 10 11 12 13 14 Optimum pH for trypsin Optimum pH
for pepsin
stomach pepsin
intestines trypsin
What’s happening here?!
reaction rate 1 2 3 4 5 6 7 8 9 10 11 12 13 14 pH

18. For enzymes… What matters?
SHAPE! SHAPE! SHAPE!

19. You need to be able to read the pH scale in order to complete this worksheet.
pH scale goes from 0-14.
It is used to measure how acidic or basic something is.

20. How to read the pH scale pH lower than 7 indicates
pH = 7 means
Neutral (water)
pH lower than 7 indicates
Acidic solution
pH greater than 7 indicates basic solution

21. Acidic
Basic
Acidic
Neutral

22. Hint: Remember, less than 7 is acidic. Greater than 7 is basic