At the end of today’s lesson, we should be able to:

define what are catalysts

define what are enzymes

state uses of enzymes

So what are catalyst?

A catalyst is a substance which can alter a

chemical reaction, without itself being

chemically changed at end of reaction.

Inorganic catalyst

Dilute acid + Metal Salt + Hydrogen

Dilute sulphuric acid + Zinc Zinc sulphate + Hydrogen

Zn(s)  + 2H2SO4 (aq)  ZnSO4(aq)  +  2H2 (g)

Enzymes are biological catalyst made of

proteins.

Enzymes can alter a chemical reaction,

without itself being chemically changed

at end of reaction.

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

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.

Advantages of enzymes?

allows reactions to be carried out at lower temperature

speeds up reaction

Enzymes

What are enzymes?

Name an example of an enzyme

catalysed process

Enzymes

Biological catalysts made of proteins

alter rate of chemical reactions

Example of enzymecatalysed process:

DigestionDetergent

remain chemicallyunchanged at theend of a reaction

characteristic of enzymes

explain enzyme action in terms of the ‘lock and key’ hypothesis.

1. Which organic compounds are enzymes made up of?

A Protein B Starch C Lipid D Carbohydrate

2. An enzyme speeds up a chemical reaction in the cell, but can only be used once.

A True B False

How does enzymes increase the rate of reaction?

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.

Enzymes speed up chemical reactions.

Enzymes are required in minute amounts

Enzymes are specific [Lock & Key analogy]

2. Any substance that is acted upon by an enzyme is called a(n)

A substrate B amino acid C active site D product

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