Enzymes

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

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.

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)

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.

Where can we find enzymes? http://www.activescience-gsk.com/miniweb/content/enzymes/reaction.htm Filler

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

Where can we find enzymes? Filler

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

Enzymes 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 What are enzymes? Enzymes

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

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

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

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

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

Enzymes in action

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.

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

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

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