1. ENZYME

2. Characteristics of enzymes
Protein in nature.
Biological catalysts. Speed up reactions without being changed or used up.
Act on reversible reaction.
Action of enzymes is specific
Work best at a certain range of pH and temperature.
Action of enzymes is affected by inhibitor

3. Characteristics of enzymes
A + B C
enzyme
Biological catalyst
Protein pH
Specificity

4. substrate
substrate
enzyme
active site

5. Action of enzyme (Anabolic reaction)
enzyme-substrate complex
enzyme-product complex
enzyme
product
enzyme
substrate

6. Action of enzyme (catabolic reaction)
enzyme-product complex
enzyme-substrate complex
products
enzyme
enzyme
substrate

7. Lock and key hypothesis
Substrate
product
Enzyme

8. Lock and key hypothesis
SHAPES DON’T MATCH

9. Factors affecting enzyme action Substrate concentration
Max. Rate
Rate of reaction
Substrate conc.

10. Factors affecting enzyme action Substrate concentration

11. Factors affecting enzyme action Temperature
Rate of reaction
Temperature（OC）

12. Factors affecting enzyme action Temperature
Each enzyme works best at a particular temperature - _____________________.
When temperature is lower than optimum temperature, activity of enzyme become ________. At low temperature, enzymes become _____________. They become _________________ when the temperature is raised.
optimum temperature
lower
inactive
active again

13. Factors affecting enzyme action Temperature
Above the optimum temperature, heat changes the _______ of enzymes and their _____________, __________ their activities.
When temperature is too high (above 60oC), most enzymes are ____________, and lose they catalytic property permanently.
shape
active sites
decreases
denatured

14. Factors affecting enzyme action pH
Rate of reaction pH

15. Application of Enzymes
Washing Powder

16. SCIENCE SECTION
CURRICULUM DEVELOPMENT INSTITUTE
EDUCATION DEPARTMENT