Topic 4 - Properties of Enzymes and Uses in

IndustriesNational 4

Cell Biology

Catalysts

Topic 4 - Properties of Enzymes and Uses in

Industries

By the end of the lesson you should be able to:

• State a catalyst speeds up the rate of reactions.

• Perform a chemical reaction using a catalyst.

Reactions

• Chemical reactions are happening in our bodies all the time.

• These reactions help us break down food and make energy.

Catalyst

• A catalyst speeds up the rate of a chemical reaction.

Hydrogen peroxide

• A nasty chemical which can burn skin.

• Over time it can break down and turn into water and oxygen.

+

Activity 1 - Lets speed it up

You will need:•GOGGLES!!

•Measuring cylinder•Spatula•Hydrogen peroxide•Catalyst (Manganese dioxide)•Washing up liquid

What to do:

1. Put 10ml of hydrogen peroxide in the measuring cylinder. Look for bubbles of oxygen.

2. Add 3 drops of washing up liquid.3. Add 1 spatula of

catalyst(manganese dioxide).4. Watch what happens...

Catalyst

• A catalyst speeds up chemical reactions.

• When manganese dioxide is added to hydrogen peroxide, the hydrogen peroxide is broken down very quickly into water and oxygen.

HYDROGEN PEROXIDE WATER AND OXYGEN

CATALYST

Catalase enzyme

Topic 4 - Properties of Enzymes and Uses in

Industries

By the end of the lesson you should know

• Enzymes are biological catalysts.

• An enzyme speeds up the rate of chemical reactions.

• Hydrogen peroxide is broken down by the enzyme catalase into water and oxygen.

• State that enzymes remain unchanged so they can be used again and again.

Enzymes

• A catalyst speeds up the rate of a reaction.

• Enzymes are biological catalysts that speed up chemical reactions.

Activity 2 - Breakdown of hydrogen peroxide

Carrot in 10ml of hydrogen peroxide +detergent

Turnip in 10ml of hydrogen peroxide +detergent

Potato in 10ml of hydrogen peroxide + detergent

Test TubeYou will set up the following experiment.

10ml of hydrogen peroxide + detergent

Test Tube Rack

Hydrogen peroxide

• Hydrogen peroxide can break down by itself but can take a long time.

• Enzymes can speed this up.• Hydrogen peroxide is present in the

cells of our body and we need to get rid of it.

• We have an enzyme in our bodies called catalase which can do this.

• Catalase is also found in various plant tissues, like carrot potato and turnip.

1. Put 10ml of hydrogen peroxide into each test tube.

2. Carefully add a piece of tissue to the first three test tubes.

3. Leave for 5 minutes.

4. Record the height of foam using a ruler.

Results

Conclusion Different types of cells have different volumes of the

enzyme CATALASE, which breaks down hydrogen peroxide. The tissue with the most catalase was _____________. We could tell this because it produced the most ________.

Hydrogen Peroxide CATALASE Water + Oxygen

Tissue Height of Foam (mm)

Carrot

Potato

Liver

Boiled Liver

Catalase

Catalase (unchanged)

Hydrogen peroxide

Catalase and hydrogen peroxide join together

Enzyme breaks up hydrogen peroxide

Water and oxygen

The enzyme can join with another substrate moleculeand repeat the reaction time after time.

Enzyme action

Hydrogen peroxide

Catalase enzyme

Matching shapes

Hydrogen peroxide joins with catalase

Water and oxygen

enzyme unchanged

Enzymes can be used over and over again as they remain unchanged by the reaction.

Amylase enzyme

Key Area 4 - Properties of Enzymes and Uses in

Industries

By the end of the lesson you should be able to:

• Describe the effect of the enzyme amylase on starch.

• Give the meaning of the words substrate and product in relation to enzymes.

Enzymes

• A catalyst speeds up the rate of a reaction.

• Enzymes are biological catalysts that speed up chemical reactions.

Breaking down starch

• Lots of our food contains starch.

• Examples of starchy foods are bread, potatoes, rice and pasta.

• Our digestive system breaks down the starch in our food into sugar.

• It is enzymes in our mouth and intestines which do this.

Activity 3 -The breakdown of starch by amylase

10 ml of starch + 3ml of amylase enzyme

Test Tube Rack

10 ml of starch + 3ml of water

Test Tube

Method1.Collect and label 2 test tubes.2.Put 10ml of starch solution in each test tube.3.Put 3ml of amylase enzyme in test tube A.4.Put 3ml of water in test tube B.5.Take a small sample of each with a dropper and transfer it to a spotting tile.6.Test both samples using iodine solution.7.Leave for 20 minutes.8.Repeat steps 5 and 6.

A B

Results

Test Tube

Iodine Solution

Colour at start of

experiment

Colour after 20 minutes

A Starch + amylase

B Starch + water

Conclusion : Starch was broken down in test tube A by the enzyme __________. The starch was not broken down in test tube B because there was no ___________ there.

Substrates and Products

• The chemical that is being reacted on is called the substrate.

• The chemicals made at the end of the reaction are called the products.

• In the last experiment, the enzyme was _________ the substrate was __________ and

the product was sugar.

Amylase

Amylase (unchanged)

Starch

Amylase and starch join together

Enzyme breaks down the starch

sugar

Enzyme can join with another substrate molecule and repeat the reaction time after time.

Conclusion

The starch is broken down into maltose by the enzyme amylase.

Word Equation ENZYME

AmylaseStarch Sugar

SUBSTRATE PRODUCT

Breakdown of Starch

StarchSUBSTRATE

SugarPRODUCT

AmylaseENZYME

Phosphorylase enzyme

Topic 4 - Properties of Enzymes and Uses in

Industries

By the end of today you will be able to:

• State that glucose can be built up into starch by phosphorylase.

• State that smaller molecules can be built up into larger molecules by enzymes.

Breakdown reaction

• A BREAKDOWN reaction occurs when a large substrate molecule is split up into smaller molecules.

Examples• Starch breaking down into sugar.• Hydrogen peroxide breaking down

into water and oxygen.

The potato story• The leaves of potato plants make

glucose.

• Some of the glucose is used by leaf cells for energy.

• Some glucose is transported to the roots for storage.

• In the roots, the glucose is built up into starch for storage. This forms starchy potatoes under the ground.

• Potatoes contain an enzyme called phosphorylase which builds up starch from glucose.

Glucose moving to roots to be stored in potatoes

Method

1. Put 3 drops of phosphorylase in each dimple of row A only.

2. Put 3 drops of water in each dimple of row B only

3. Put 3 drops of glucose in each dimple of row A and row B.

4. Add 3 drops of iodine solution into column 1. Then start the clock.

5. After 3 mins put some iodine in the three dimple of column 2. Repeat at 6mins in column 3, and 9 mins in column 4.

glucose + phosphorylase

1 2 3 4

glucose + water

A

B

Activity 4 – Build up of glucose into starch

0 mins 3 mins 6 mins 9 mins

A        

glucose + phosphorylase

       

B        

glucose + water        

Results

Conclusion

Potatoes contain an enzyme _______________ which builds up glucose into _____________.

Glucose Starch

SUBSTRATE PRODUCT

Time Row

Phosphorylase

Build Up Reaction

• A BUILD UP reaction occurs is when a substrate with small molecules is joined up into larger molecules.

GlucoseSUBSTRATE

Phosphorylase

StarchPRODUCT

Enzymes are Specific!

By the end of today you will be able to:

• State enzymes are made from protein.

• Explain the phrase ‘enzymes are specific’.

• Prove that enzymes are specific.

Enzymes are specific

• If something is specific, it applies to only one situation.

• To open the front door of your house, you need a specific key. Any key will not do.

• You are going to carry out an investigation to demonstrate that enzymes are specific.

Enzymes

• Enzymes are made of protein and are found in all cells.

Made of protein

Enzymes and substrates have different shapes.

Enzymes are said to be specific

This means they only speed up one reaction as theyonly fit with one substrate. Each substrate has a different shape. Each enzyme also has a different shape.

Substrate 1 fits into enzymeso reaction takes place.

Substrate 2 does not fit into enzyme so reaction does not takes place.

No reaction

Substrate 1Substrate 2

Activity 5 – Which enzyme is amylase?

EquipmentEnzyme bottles A, B and CBottle of starch3 boiling tubesTest tube rackMeasuring cylinder3 syringesIodine solutionLabels

Activity 5 – Which enzyme is amylase?

Method1. Label 3 boiling tubes A, B and C.2. Add 5ml of starch solution to each boiling tube.3. Add 2ml of enzyme A to tube A, 2ml of enzyme

B to tube B and 2ml of enzyme C to tube C.4. Place in a water bath at 37°C and leave for 20

minutes .5. Remove 3 drops from test tube A onto a

spotting tile. 6. Wash the dropper and repeat for B and C.7. Add 2 drops of iodine solution to each dimple.

Activity 5 – Which enzyme is amylase?

Results

Starch + enzyme A

Starch + enzyme B

Starch + enzyme C

Starch present

or absent?

Activity 5 – Which enzyme is amylase?

Conclusion

In boiling tube the starch was broken down.

This means enzyme _______was amylase.

Effect of temperature on enzymes

By the end of the lesson you should be able to:

• State how enzymes are affected at different temperatures.

• Carry out an investigation to examine the effect of temperature on catalase enzyme using potato.

• Define the term denatured.

Enzymes

• Enzymes speed up the rate of biochemical reactions.

• Catalase is an enzyme which breaks down hydrogen peroxide into water and oxygen.

Aim

• The aim of the experiment is to find out how different temperatures affect the breakdown of hydrogen peroxide.

Activity 6 :The effects of temperature on catalase

10ml of cold hydrogen peroxide and detergent

+ frozen potato

10ml of hydrogen peroxide and detergent

+ normal potato

10ml of hydrogen peroxide and detergent

+ boiled potato

Test TubeYou will set up the following experiment.A B C

Method

1. Fill 3 test tubes with 10ml of hydrogen peroxide in each. Use the cold hydrogen peroxide for test tube A.

2. Collect the 3 different types of potato and add to the correct tubes.

3. Leave for five minutes.4. Measure the height of the foam

produced in each test tube.

Results

Type of potatoHeight of foam produced (mm)

Frozen potato

Normal potato

Boiled potato

Conclusion

• At which temperature does the catalase in the potato breakdown the hydrogen peroxide the best?

• How did you know which temperature was the best?

Enzymes and temperature

• If the temperature is too COLD the enzyme molecules and substrate molecules move about too SLOWLY to join up with each other properly.

• The reaction happens, but very slowly.

• As the temperature increases the molecules move about quickly and the reaction happens quickly.

• If the temperature is too HOT the enzyme molecules CHANGE SHAPE so the enzyme is destroyed and CANNOT join with the substrate.

• This is called a denatured enzyme.

Catalase denatured by heat

Hydrogen peroxide

Catalase and hydrogen peroxide cannot join together

No reaction happens.

Even when cooled down, the shape of the enzyme does not go back to normal, so the enzyme is permanently destroyed.

Detergents

Topic 4 - Properties of Enzymes and Uses in

Industries

By the end of today you will be able to:

• Describe the difference between a biological and non-biological detergent.

• State the advantages and disadvantages of biological detergent.

• Experiment with biological and non-biological detergents.

Washing powders and liquids are also called detergents.

•You may have heard of the terms: “bio” (short for biological) and “non bio” (short for non-biological)

Bio detergents contain enzymes which help to break down food stains. This means they work well at low temperature washes.

•Enzymes can be used in industry.

•Biological detergents contain enzymes that are made by genetically engineered bacterial cells.

Enzymes in Industry

The use of enzymes in detergents

• Enzymes in detergents digest the stains on clothes.

• These enzymes are similar to the enzymes in our gut that digest our food.

• Bio detergents contain several different enzymes.

• Different enzymes digest different stains.– Fat digesting enzymes digest fatty stains like butter and

lipstick.– Protein digesting enzymes digest protein stains like egg

and blood.

Activity 7 - Investigating Bio & Non-Bio detergents

Water bath at 40oC

Stain on cloths

biological washing powder A B

non-biological washing powder

Activity 7 - Investigating Bio & Non-

Bio detergents

1. Label 2 boiling tubes “bio” & “non-bio”.2. Half fill one tube with “bio” detergent and half

fill the other with “non-bio”.3. Collect 2 pieces of cloth stained with the

same stain.4. Add a stained cloth to each boiling tube.5. Place tubes in a water bath at 40°C.6. After 25 minutes check if stains have been

removed.

Results

Test-Tube

Stain Detergent

Result

A Biological

B Non-biological

Biological washing powders are used at lower temperatures. The advantage of this is:• they are kinder to delicate fabrics• it save money as water does not need to be heated so much

Do you think there are any disadvantages to usingbiological detergents?

Advantages of Biological Washing Powders

The enzymes in biological detergents can cause allergic reactions such as eczema in some people.

Disadvantages of Biological Washing Powders

Allergic reactions

Cheese Making

Topic 4 - Properties of Enzymes and Uses in

Industries

By the end of today you should be able to:

• Describe how cheese is made• Describe what rennet does to milk• Describe what happens to the curds

and whey• State where rennet is obtained from

Starter

1. Which type of detergent contains enzymes?

2. What kind of cells are used to make enzymes?

3. Name one advantage of using biological detergents.

4. Name a disadvantage of using biological detergents.

An enzyme called rennet is used in the process of cheese making:

Cheese Making

Step 1:

Find a cow

Milk the cow

Making Cheese

Step 1:

OR you can also make cheese using milk from a sheep, goat of buffalo.

Making Cheese

Step 1:

If you can’t find a cow, goat,sheep, buffalo or any other animal you could milk, then just buy a carton of milk.

Making Cheese

Step 2:

Pasteurise the milk(unless you purchased it froma supermarket and it willalready be pasteurised!).

Pasteurising kills unwanted or harmful bacteria as well asgiving milk a longer shelf life.

To pasteurise milk, heat it to 72oCfor 15 seconds then quickly cool to 5-10oC.

Making Cheese

Step 3:

Add a starter culture.

This contains bacteria that will convert thelactose sugar in milk to lactic acid.

Making Cheese

Starter culture (bacteria)

Acidic milk

Step 4:

Add rennet to the acidic milk solution.

Rennet clots the protein in milk to make it form a solid and a liquid.

The solid is called curds.

The liquid is called whey.

Making Cheese

Step 5:

Separate the curds from the whey.

This can be done with a sieve or a muslin cloth.

http://www.youtube.com/watch?v=CJbPo7HqjPshttp://www.youtube.com/watch?v=aImiN_8ELWI

Making Cheese

Curds & Whey

CurdsWhey

Curds are the lumps formed when the milk clots. This is the part used to make cheese.

Whey is the liquid that separates away from the curds. It is not needed in cheesemaking but can be used for other things.

Step 6

The curds are pressed in a mould and then matured to form cheese.

The longer the curds are leftto mature, the stronger the cheese.

Making Cheese

Cheese making

Whey

A waste product that can be used to make:

- sweeteners- gels for processed meats- alcoholic drinks ie. Baileys

Making Cheese

Cheese Making Summary

• A starter culture is added to pasteurised milk to cause the milk to become acidic.

• Rennet is added to the acid milk to cause the protein to clot.

• The solid lumps formed when the protein clots are called curds and the liquid is referred to as whey.

• The curds are separated from the whey and pressed together to form solid cheese.

There are two types of rennet used in cheese making:

• Calf Rennet (from calves’ stomachs)• Genetically Engineered Rennet (from fungus)

Where does rennet come from?

• Calf Rennet

• Advantage – Natural product, not genetically engineered• Disadvantage – Lots of calves are killed to get the rennet from their stomachs.

• Genetically Engineered Rennet

• Advantage – Calves are not killed in the production, useful for vegetarians• Disadvantage – Long term effects of genetic engineering are unknown

Activity 8 - Cheese Making1. Measure 50 ml full fat milk into a small beaker

labelled with your initials.

2. Heat the milk to 50˚C in a waterbath for 5 minutes (use a stopwatch to time).

3. Add 1 spatula of rennet powder to milk and STIR.

4. Once curds have formed, filter the mixture using a muslin cloth into a fresh beaker.

 5. Remove any remaining liquid by squeezing the

muslin.