1. MENU OF THE DAY

2. TEMPER SIZE SPEED HEIGHT

3. Enzymes’

4. Enzyme Characteristic 1 Enzymes _________ __________ chemical reactions. speedup

5. Enzyme Characteristic 2 Tube ATube BTube C Tube ATube BTube C ContainsH 2 O 2 & sandH 2 O 2 & liver Observation

6. Tube ATube BTube C Minute amounts of enzymes is needed to speed up the rate of reaction, without being chemically changed at the end of the reaction. Enzymes are required in minute amounts.

7. Maltase Enzymes are required in minute amounts. At the end of a chemical reaction, enzymes remain chemically unchanged and capable of catalysing more reactions. Maltose Glu

8. Maltase At the end of a chemical reaction, enzymes remain chemically unchanged and capable of catalysing more reactions. Maltose Glu Enzymes are required in minute amounts.

9. Maltase At the end of a chemical reaction, enzymes remain chemically unchanged and capable of catalysing more reactions. Maltose Glu Enzymes are required in minute amounts.

10. Maltase At the end of a chemical reaction, enzymes remain chemically unchanged and capable of catalysing more reactions. Maltose Glu Enzymes are required in minute amounts.

11. Maltase Maltose Glu Hence, a minute amount of enzymes is enough to catalyse a chemical reaction. Enzymes are required in minute amounts. Since enzymes remain chemically unchanged in the reactions they catalyse, the same enzyme can be used over and over again.

12. Recall How do we name enzymes? Based on the substrate they act on!

13. Enzymes are substrate specific. Amylase Starch Protease Proteins Enzyme Characteristic 3 ACT ON Lipids/ FatsLipase Substrates ACT ON

14. Enzyme Characteristic 3 An Enzyme

15. Active site A depression on the surface of an enzyme molecule into which the substrate molecule(s) can fit Enzyme Characteristic 3 The specificity of an enzyme is due to its surface configuration or active site.

16. Demonstration

17. According to the “lock and key” hypothesis, the enzyme action depends on the active site.

18. Unsuitable substrate molecules will NOT FIT into the active site. Hence, the enzyme will not catalyse the reaction. A B

19. C D CD ONLY suitable substrate molecules will fit into the active site. The enzyme will then be able to catalyse the reaction.

20. Only certain substrate can fit the active site of an enzyme.

21. lock key

22. Each enzyme is a molecule with a specific shape. On part of its surface is the active site (the lock)—a section where its substrate molecule (the key) fits exactly.

23. When the substrate molecule is in position in the active site, the enzyme alters the substrate, splitting it into its product molecules.

24. The product molecules drift away from the enzyme molecule leaving its active site free to operate again.

26. What we learn today. Characteristics of Enzymes (Think: What are they?) “Lock and Key” Hypothesis (Describe)