DDuunnccaannrriigg SSeeccoonnddaarryy …...2 National 4 Biology, Duncanrig Secondary School CG....

DDuunnccaannrriigg SSeeccoonnddaarryy SScchhooooll

NNaattiioonnaall 44 BBiioollooggyy UUnniitt 11

TTooppiicc 44 aanndd 55::

EEnnzzyymmeess aanndd MMiiccrroo OOrrggaanniissmmss iinn IInndduussttrryy

PPuuppiillss’’ AAccttiivviittyy BBooookklleett

http://www.google.co.uk/url?sa=i&rct=j&q=&esrc=s&frm=1&source=images&cd=&cad=rja&docid=uCArVxZK_3F7TM&tbnid=_Z-eBOjrzvJEgM:&ved=0CAUQjRw&url=http://www.lifeplusvitamins.com/enzymes.htm&ei=L6KXUuj9G-uo0wWEqYHgBg&psig=AFQjCNFNpbw324jeRE6pN_DWHalYvilpdQ&ust=1385755105224001

2

National 4 Biology, Duncanrig Secondary School CG.

Unit 1 Topic 4 and 5 Enzymes and Micro Organisms in Industry

What you should know by the end of this unit:

Enzymes are made of protein.

Enzymes are made in living cells.

Enzymes are biological catalysts that speed up chemical reactions but

remain unchanged.

A substrate is the substance upon which the enzyme acts.

The substance formed as a result of enzyme action is called a

product.

Enzymes are specific.

Specific means the enzyme only acts on one substrate.

Enzymes control breakdown and synthesis reactions.

One example of a breakdown reaction.

A synthesis reaction is a “building up” reaction.

One example of a synthesis reaction.

Biotechnology is the use of living things to make useful products.

Yeast and bacteria are micro organisms used in biotechnology.

Biological washing powders contain enzymes, made by bacteria.

In the absence of oxygen, yeast will convert sugar into alcohol and

carbon dioxide.

Yeast is used in bread making to make dough rise, due to the carbon

dioxide produced.

Yeast is used in beer and wine making, due to the alcohol produced.

Bacteria convert lactose in milk to lactic acid for the production of

yoghurt.

Rennet is an enzyme that is used in cheese production.

Bacteria are used in the manufacture of biofuels.

Skills that you should be able to carry out by the end of this unit

are:

Construct a table.

Work as part of a group and take responsibility to support the work

of the group.

Follow instructions to carry out experiments in a safe manner.

3



Experiment 1: The Activity of Catalase The enzyme, catalase, is found in a variety of tissues. Its function is to

break down the harmful substance hydrogen peroxide, which is a

toxic waste produced by our body cells, into harmless oxygen and water.

This type of reaction is therefore called a breakdown reaction.

The activity of the enzyme can be measured by the height of the

oxygen froth created during the reaction.

Aim: To show that the enzyme catalase can be found in a variety of

living tissues.

Collect:

safety goggles ruler

4 test tubes and test tube rack hydrogen peroxide solution

3 pieces of living tissue and 1 piece of boiled tissue

small measuring cylinder

Method:

1. Label 4 test tubes A, B, C and D.

2. Add 5ml of hydrogen peroxide into each of the four test tubes.

3. Add a different tissue to each tube.

4. Wait 30 seconds.

5. Use a ruler to measure the height of the froth, from the surface of

the liquid to the top of the froth.

Properties of Enzymes

Enzymes are proteins made by and found in all living cells. They are essential to

the cell because they speed up chemical reactions. Without enzymes, chemical

reactions in the cell would proceed too slowly to maintain life.

Enzymes are not changed by chemical reactions so they can be used over and

over again. Many industrial processes use enzymes because of this property.

Hydrogen peroxide is corrosive. Wear safety goggles. Follow all teacher instructions carefully.

4



The experiment set up is shown here to help you:

Results (copy and complete the table in your jotter):

Graph: Draw a bar graph of your results using a ruler and a pencil.

Remember the following:

Include labels and units on both axes

A scale with even divisions

Accurate bars with bar tops which are straight.

Conclusion (copy and complete the sentence in your jotter):

The enzyme ______________ is found in living tissues. It breaks down

hydrogen peroxide to produce __________ and _____________.

Tissue type Height of Froth (mm)

potato

carrot

liver

boiled tissue

B C D

height of

froth

produced

oxygen

froth

5ml

hydrogen

peroxide

tissue (potato, carrot, liver or boiled tissue)

A

5



Specificity of Enzymes

Enzymes are specific. This means that each enzyme can only act on one

type of substance. The substance that the enzyme works upon is known as

its substrate. The substance formed as a result of the chemical reaction is

called the product.

The shape of the enzyme fits exactly with the shape of the substrate at the

active site.

one enzyme one reaction

enzyme enzyme

substrate substrate

substrate

6



Experiment 2: The Specificity of Enzymes

Aim: To find out which enzyme A, B, C or D is amylase.

Collect:

4 boiling tubes and rack

enzyme solutions A, B, C and D

starch solution


Method:

Set the experiment up as shown in the diagram below.

Wear safety goggles.

Follow all teacher

instructions carefully.

5ml starch

+

enzyme A

5ml starch

+

enzyme B

5ml starch

+

enzyme C

5ml starch

+

enzyme D

Enzymes are Specific

One type of reaction that enzymes are involved in is a breakdown

reaction, you have already seen an example of this using the enzyme

catalase. The enzyme amylase breaks down the substrate starch into

simple sugar. We can test for the presence of sugar using Benedict’s

solution, which will turn from a bright blue colour to brick red or orange

when sugar is present.

7



Method (continued):

1. Label your boiling tubes with your initials and A, B, C or D.

2. Using a small measuring cylinder measure 5ml of starch and add to

each test tube.

3. Measure 5ml of the correct enzyme to each labelled tube.

IMPORTANT: Clean your measuring cylinder between each

enzyme to avoid contamination.

4. Leave the test tubes for 20 minutes on the work bench.

5. After 20 minutes add 10 drops of Benedict’s solution to each tube and

heat to 90oC using a water bath for a few minutes.

6. Note down any colour change.

Results (copy and complete the table into your jotter):


Enzyme ____ was amylase because it broke down the starch to produce

________________ which turned the Benedict’s Solution _____________.

Enzyme Colour of Benedict’s

Solution

Presence of Sugar?

(yes/no)

A

B

C

D

8



Key Questions

Copy the following statements into your jotter and complete them

by choosing one option from each set of brackets.

1. Enzymes are found in (all / some) living cells.

2. Enzymes (slow down / speed up) chemical reactions but are

(changed / unchanged) by the reaction.

3. Enzymes are specific. This means that each enzyme can only

act on (one type / many types) of substance.

4. The substance that the enzyme works upon is known as its

(substrate / product).

5. The substance formed as a result of the chemical reaction is

called the (substrate / product).

?

9



Experiment 3: The Activity of Pepsin

Another enzyme involved in the breakdown of large molecules into smaller

ones is pepsin. The enzyme pepsin, found in the stomach, can breakdown

the large molecule protein into smaller peptides molecules.

Aim: To investigate the action of the enzyme pepsin.

Collect:

safety goggles


dropper bottle acid

dropper bottle alkali

dropper bottle of water

pepsin

cloudy egg white suspension


Method:

1. Label the boiling tubes with your initials and A, B and C.

2. Shake the bottle of egg white. Then use a measuring cylinder to add

5ml of cloudy egg white to each test tube.

3. Using a different dropper each time or carefully rinsing the dropper

between each solution, add 10 drops of acid to tube A , 10 drops of

water to tube B and 10 drops of alkali to tube C.

4. Shake the bottle of pepsin. Then use a clean measuring cylinder to

add 5ml pepsin to each boiling tube.

5. Place the 3 boiling tubes in the water bath and leave for 20 minutes.

6. Examine each tube and note down any change in appearance.


Follow all teacher


10





In test tube ___ the ____________ in the egg white was broken down by

the pepsin to produce small peptides. Pepsin works best at pH ____.

“Pepsin is found in the stomach where it is used to breakdown

protein.”

Use this statement to explain your results.

Tube Appearance

at Start

Appearance

at End

A

B

C

Tube A:

5ml egg white

10 drops of acid

5ml pepsin

Tube B:

5ml egg white

10 drops of water

5ml pepsin

Tube C:

5ml egg white

10 drops of alkali

5ml pepsin

11



Synthesis Reactions

Some enzymes allow the build-up of small molecules into larger ones. The

enzyme phosphorylase, found in potatoes, can build-up the small molecule

glucose-1-phosphate into the larger molecule starch.

substrates

enzyme/

substrate

complex

enzyme

product

enzyme

Step 1

Step 2

Step 3

12



Experiment 4: The Activity of Phosphorylase, a Synthesis Reaction

Aim: To investigate the effect of the enzyme potato phosphorylase on the

substrate glucose-1-phosphate.

Collect:

potato extract (containing phosphorylase) iodine

glucose-1-phosphate 2 droppers

distilled water spotting tile

Method:

1. Label 3 wells on your spotting tile A-C

as shown in the diagram below.

2. Add 3 drops of glucose-1-phosphate and 3 drops of potato extract to

well A , using separate droppers to avoid contamination.

3. Add 3 drops of glucose-1-phosphate and 3 drops of distilled water to

well B.

4. Add 3 drops of potato extract and 3 drops of distilled water to well C.

5. Wait 15 to 20 minutes to allow the enzyme time to break down the

substrate.

6. Add 2 drops of iodine to each well and observe any colour change.

(The solution will turn from brown to blue/black if starch is present.)

potato extract + glucose-1-phosphate

glucose -1- phosphate + water

potato extract + water

A

B

C


Follow all teacher


13




Row Contents

Colour of the

Iodine Solution

After 20 Minutes

Starch Present?

(yes or no)

A potato extract +

glucose –1– phosphate

B glucose –1– phosphate

+ water

C potato extract + water

Conclusion (copy and complete the sentence into your jotter):

In order to produce starch, ________________ and

___________________ both need to be present.

Key Questions: Answer in sentences in your jotter. 1. What substance, present in potato extract, has carried out

the build up of the substrate glucose-1-phosphate into starch?

2. Wells B and C are controls. What is a control?

3. Copy and complete the word equation to summarise the

reaction observed in this experiment.

___________ + ____________ _____________ (substrate) (enzyme) (product)

?

14



Activity

Copy each list and use a straight line to match the enzyme with the

substrate to which it is specific.

Enzyme Substrate

Phosphorylase Protein

Catalase Starch

Amylase Glucose-1-phosphate

Pepsin Hydrogen Peroxide

Some enzymes break down large molecules into smaller molecules.

Amylase and pepsin are examples of enzymes that are involved in

'breakdown' reactions.

Collect three colours of plasticene and make a 3D model of an

enzyme ‘breakdown reaction.’ You can invent the shape.

Draw a diagram of your model and label the following:

a. Enzyme A

b. Active site

c. Substrate

d. Product(s)

Some enzymes build up or synthesise smaller molecules into larger

molecules. Phosphorylase is an example of an enzyme involved in a

synthesis reaction.

Use the plasticene to show a synthesis reaction. Again, you can

invent the shape.

Draw a diagram of your model and label the following:

e. Enzyme B

f. Active site

g. Substrate(s)

h. Product

http://www.google.co.uk/url?sa=i&rct=j&q=&esrc=s&frm=1&source=images&cd=&cad=rja&docid=g2gLPtcq25GF7M&tbnid=UmllX1i5NttYVM:&ved=0CAUQjRw&url=http://newsnewmexico.blogspot.com/2011_02_24_archive.html&ei=0QhXUtrJFInW0QXh5YCgBw&bvm=bv.53760139,d.d2k&psig=AFQjCNGd72ZiosyTCcXMn1VKubzQ51qM1w&ust=1381521705127567

15



Activity

Uses of Enzymes in Industry

Biotechnology is the use of living things to make useful products.

Enzymes made by living organisms are used in a range of

biotechnological industries. Some shown below:

We eat enzymes in most liquid food items

we buy (cheese, yogurt, juices, wine and beer).

Enzymes are used in the production of fabrics

and when we wash our clothes.

Enzymes are used in the manufacture of

paper.

Use the information and

pictures on this page to help

you.

Copy the heading “Uses

of Enzymes in Industry”

into your jotter and make

a list of as many as you

can.


16



Activity

Enzymes can be used in a range of biotechnology industries.

Copy the statements and industries listed below. Then draw a

straight line to match up the enzyme to the industry it is used in:

Enzyme Industry

protein digesting enzyme for stain

removal

enzyme that removes impurities from

cotton

enzyme found in microbes such as

yeast that converts sugar into alcohol

enzyme called rennet which is added

to milk to clot it

brewing

washing powder

production

fabric production

cheese making


17



Experiment 5: The Action of Biological Washing Powder.

Aim: To compare the effect of biological and non-biological

washing powders on a range of stains.

Collect:


glass stirring rod

6 stained fabric squares (2 of each stain type)

biological and non-biological washing powder

Method:

Use the diagram below to help you set up the experiment following the

instructions on page 18.

Wear safety

goggles.

Follow all teacher

instructions

carefully.

Uses of Micro Organisms: Washing Powders

Some washing powders are biological which means that they contain

enzymes. Enzymes help to digest the stains which can then be washed

away. The enzymes are produced by bacteria, which is a micro organism and

then added to the washing powders.

stain type 1 stain type 2 stain type 3

A B C D E F

biological non

biological

non

biological

non

biological

biological biological

washing powder type

W

w

18



Method (continued): 1. Work in a group of 3, each member of the group will set up one of the

stain types.

2. Label the 6 boiling tubes with your initials and A-F.

3. Add 10ml of biological washing powder to tubes A,C and E and

10ml of non-biological washing powder to tubes B, D and F.

4. Place a stained fabric square in each tube as shown in the diagram

(page 17).

5. Place the boiling tubes in a water bath at 40˚C for 20 minutes but

return to stir it every 5 minutes.

6. After 20 minutes, examine the stains for any changes in size and the

water for changes in colour.

Results: (copy and complete the table in your jotter)

Tube Stain Type Washing Powder

Type Result

A biological

B non biological

C biological

D non biological

E biological

F non biological


The most effective washing powder is ________________ because it

contains ______________ to digest stains.

19



Experiment 6: The Effect of Temperature on Yeast

Aim: To investigate the effect of temperature on dough rising.

Collect:

3 plastic beakers flour

dropper bottle of glucose solution spoon

dried yeast + spatula china graph marker pencil

Method:

1. Label 3 plastic beakers with your initials and A, B and C.

2. Make up the dough mixture in one plastic beaker by adding 5 spoons of

flour, 1 spatula of yeast and glucose solution a few drops at a time until

you have a firm but sticky mixture.

3. Separate the dough evenly between the 3 beakers.

4. Mark the height of the dough by drawing a line on the outside of the

beakers at the start.

5. Place beaker A into the fridge, keep beaker B at room temperature and

place beaker C into the water bath.

6. Leave for 24 hours.

7. Mark the height of the dough after 24 hours.

Uses of Micro Organisms: Bread Making

Yeast is a tiny, single celled fungus. Yeast can be used by in the baking industry

to make bread dough rise. As with all living organisms, yeast must respire. As

yeast respires the sugar in the dough is used and carbon dioxide and alcohol is

produced. In bread making, the carbon dioxide bubbles get trapped in the

dough, causing it to rise. The alcohol evaporates during the baking process. This

special type of respiration in yeast is called fermentation.

20



8. Measure the difference between the starting height and final height, using a ruler.

9. Note the results in a results table.


Beaker Condition Change in height of dough (cm)

A fridge

B room temp.

C warm water bath

Graph: Draw a bar graph of your results using a ruler and a pencil.

Remember the following:

Include labels and units on both axes

A scale with even divisions

Accurate bars with bar tops which are straight.


The dough which was kept at _________ temperature had the greatest

increase in height. In this beaker more ____________ ____________ gas

was produced.

Evaluation:

What variables did you keep the same each time?

Can you think of any sources of error or improvements you could make?

initial

height of

dough

final

height of

dough

24 hours later

21



Key Questions

Copy the following statements into your jotter and complete them

by choosing one option from each set of brackets.

1. Micro organisms are so small that you need a (microscope /

telescope) to see them.

2. Properties of micro organisms include (slow / rapid) growth, (wide / narrow) range of food source and (wide / narrow) range of products.

3. Yeast is a tiny (bacteria / fungus), which can be used for

baking and (brewing / yoghurt making).

Copy and complete the following word equation showing how yeast

is used in bread making.

sugar c_______ d_______ + a________

4. What is the name given to this process in yeast?

5. Yeast produce alcohol. Is bread alcoholic? Explain your answer.

?

yeast

22



Uses of Micro Organisms: Yoghurt Making

Special strains of bacteria can be used in the process of making yoghurt.

As with all living organisms, bacteria respire. They use the lactose sugar

in the milk to produce lactic acid, which makes the proteins in the milk

thicken and clot. This is another example of the type of respiration called

fermentation.

The Process of Yoghurt Making.

Milk is heated to 80oC for 15 minutes to kill harmful bacteria, remove air

and change the milk proteins.

Milk is blended and cooled to 40oC.

Special strains of yoghurt bacteria are added to the milk to convert the milk

sugar lactose into lactic acid. The bacteria will give the yoghurt its

distinctive sour taste.

After 6 hours the yoghurt is cooled to 4oC to prevent further fermentation

by the bacteria.

The yoghurt is out into pots and can have fruit or flavourings added to it.

23



Experiment 7: Making Yoghurt Aim: To investigate the use of bacteria in yoghurt making Collect:

natural bio yoghurt thermometer

100ml milk 250ml beaker

plastic cup tripod stand

glass rod spatula

Bunsen burner and cling film

heatproof mat universal indicator and pH charts

Method:

1. Label a beaker with your initials.

2. Measure 100ml of milk into the beaker.

3. Gently heat the milk to 80C using the Bunsen burner. (Do not let it

go above 90C)

4. Switch off the Bunsen and leave the beaker on the tripod stand until

the milk has cooled to 40C.

5. Add one spatula of natural yoghurt to the milk and stir well with a

glass rod.

6. Remove a small sample and test its pH.

7. When the milk has cooled further, pour it into a plastic cup and cover with cling film.

8. Leave in a warm place until next lesson, observe any changes in

appearance and pH.

24




Time

(days) pH Appearance

0

1


After 24 hours, the pH of the milk had ____________ which means that

the milk had become more ___________. In addition the milk appeared

___________________________________________________________.

Key Questions Answer in sentences in your jotter. 1. What type of micro organism is involved in yoghurt making?

2. Copy and complete the following word equation summarising this

process.

lactose l________ a_______

3. What effect does the lactic acid have on the milk proteins?

4. What is the name given to this special type of respiration in

bacteria?

?

bacteria

25



The Use of Micro Organisms and Enzymes: Cheese Making

Cheese is made using bacteria. Cow’s, goat’s and sheep’s milk can be

used to make cheese. A special enzyme called rennet is added to the

milk which separates the milk producing solid curd and liquid whey.

The curd is then turned into cheese by adding salt and different strains of

bacteria that give cheese its distinctive flavour.

The Process of Cheese Making.

Milk is taken from a cow.

Special cultures of cheese-making bacteria are added to the milk. These

bacteria change the lactose sugars into lactic acid.

The enzyme rennet is added to the culture, causing the milk to separate

into curds and whey. Curds are solid milk proteins and whey is liquid.

The whey is removed. The remaining curds are chopped up and mixed

with salt (a preservative).

Finally, the cheese is packaged and left to mature.

Activity

Collect a copy of the cheese production and yoghurt production flow

diagrams and use the information on pages 22 and 25 to complete

them.


26



Experiment 8: Rennet and Milk Investigation

Aim: Investigate the effect of rennet on milk

Collect:

two boiling tubes and stoppers dropping bottle of rennet

measuring cylinder pasteurised milk

dropping bottle of water water bath at 37˚C (shared)

Method:

1. Label two boiling tubes with your initials and A or B. Use the diagram

below will help you.

2. Add 10ml of milk to each boiling tube.

3. Add 2ml of rennet to tube A.

4. Add 2ml of water to tube B. Remember to clean the measuring

cylinder thoroughly between step 3 and 4 to avoid

contamination.

5. Place stoppers on both tubes and place in the water bath.

6. Leave for 20 minutes then observe the appearance of both tubes.

A B 10ml milk +

2ml of rennet

10ml milk +

2ml of water

27





Milk sample ___ appeared to change from a l________________ to a

s____________ because the enzyme r________ present in this sample

clots the milk to produce solid c________ and liquid w________.

Tube Contents Appearance after 20 minutes

A milk +

rennet

B milk +

water

Key Questions Answer in sentences in your jotter.

1. What type of micro organism is involved in cheese making?

2. Copy and complete the word equation summarising the action of

bacteria in cheese making.

lactose l_______ a_______

3. What effect does this have on the milk proteins?

4. Name the enzyme used in cheese making.

5. What is the function of this enzyme in cheese making?

?

bacteria

28



Uses of Micro Organisms: Biofuels

Bacteria can also be used to make fuels, reducing our reliance on fossil fuels.

For example, bioethanol is made from fermentation of sugars by bacteria and

can be used as an alternative to petrol.

29



Key Questions

Use information from page 28 to answer the following questions in

sentences in your jotter.

1. What is the initial source of energy for the process of making

biofuels.

2. What process do the trees carry out using this energy?

3. What is extracted from the trees during pre processing?

4. Describe the role of enzymes in the making of biofuels.

5. What substance from the biomass do the micro organisms feed

on?

6. What substance is produced during fermentation and what is it

used for?

7. What compound is recycled by the whole process?

?

Date post:	26-Jun-2020
Category:	Documents
Upload:	others
View:	4 times
Download:	0 times

DDuunnccaannrriigg SSeeccoonnddaarryy …...2 National 4 Biology, Duncanrig Secondary School CG....

Documents