1. Enzymes

2. Objectives At the end of today’s lesson, we should be able to:
define what are catalysts
define what are enzymes
state uses of enzymes

3. Catalyst So what are catalyst?
A catalyst is a substance which can alter a chemical reaction, without itself being chemically changed at end of reaction.

4. Catalyst Inorganic catalyst Zn(s) + 2H2SO4 (aq) ZnSO4(aq) + 2H2 (g)
Dilute acid + Metal Salt + Hydrogen
Dilute sulphuric acid + Zinc Zinc sulphate + Hydrogen
Zn(s)  + 2H2SO4 (aq)  ZnSO4(aq)  +  2H2 (g)

5. Enzymes are biological catalyst
Enzymes are biological catalyst made of proteins.
Enzymes can alter a chemical reaction, without itself being chemically changed at end of reaction.

6. Where can we find enzymes?
Filler

7. Examples of enzymes Class of enzyme Acts on Digested products Amylase
Starch
Maltose (complex sugar)
Maltase
Maltose
Glucose (simple sugar)
Protease
Proteins
Amino acids
Lipase
Fats
Fatty acids and glycerol

8. Where can we find enzymes?
Filler

9. Where can we find enzymes?
Enzymes can be taken out of organisms, purified and then used in science and industry.
One common use in the home is in biological washing powders. These contain amylase, lipases and proteases and break down any stains that contain carbohydrate, fat and protein.  They therefore digest “biological” stains from the clothes. Since enzymes work at a low temperature this saves electricity and makes them good for delicate fabrics.
Some people, however, are allergic to the enzymes and suffer skin problems.
Filler

10. Enzymes Advantages of enzymes?
allows reactions to be carried out at lower temperature
speeds up reaction

11. Enzymes What are enzymes? Name an example of an enzyme
catalysed process
What are
enzymes?
Enzymes

12. Enzymes Digestion Detergent Example of enzyme catalysed process:
Biological catalysts
made of proteins
Enzymes
alter rate of
chemical reactions
remain chemically
unchanged at the
end of a reaction

13. What’s next? characteristic of enzymes
explain enzyme action in terms of the ‘lock and key’ hypothesis.

14. Q&A 1. Which organic compounds are enzymes made up of? A Protein
B Starch
C Lipid
D Carbohydrate

15. Q&A
2. An enzyme speeds up a chemical reaction in the cell, but can only be used once.
A True
B False

16. Filler Text

17. How does enzymes work?
How does enzymes increase the rate of reaction?

18. Enzymes in action

19. How does enzymes work? Substrates: Substances that enzymes work on
The substrate binds with the enzyme active site and an enzyme substrate complex is formed.
The substrate is broken down into a product and is released from the active site. The active site is now free to accept another substrate molecule.

20. Characteristics of Enzymes
Enzymes speed up chemical reactions.
Enzymes are required in minute amounts
Enzymes are specific [Lock & Key analogy]
Locks and keys activity

21. Q&A 2. Any substance that is acted upon by an enzyme is called a(n)
A substrate
B amino acid
C active site
D product

22. Q&A 3. Here are some stages of an enzyme controlled reaction
An enzyme substrate complex is represented by diagram
A. A
B. B
C. C
D. D