Topic 4 - Properties of
Enzymes and Uses in Industries
National 4
Cell Biology
Topic 4 - Properties of Enzymes
and Uses in Industries
Catalysts
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
CATALYST
WATER AND OXYGEN
Topic 4 - Properties of Enzymes
and Uses in Industries
Catalase enzyme
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
You will set up the following experiment.
Carrot in
10ml of
hydrogen
peroxide
+detergent
Turnip in
10ml of
hydrogen
peroxide
+detergent
Test Tube
Potato in
10ml of
hydrogen
peroxide +
detergent
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
Tissue
Height of Foam (mm)
Carrot
Potato
Liver
Boiled Liver
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
Catalase
Hydrogen
peroxide
Catalase and
hydrogen
peroxide join
together
Enzyme
breaks up
hydrogen
peroxide
The enzyme can join
with another
substrate molecule
and repeat the
reaction time after
time.
Catalase
(unchanged)
Water
and
oxygen
Enzyme action
Enzymes can be used over and over again as they remain unchanged
by the reaction.
Hydrogen
peroxide
Water and oxygen
Hydrogen peroxide
joins with catalase
Matching
shapes
Catalase enzyme
enzyme unchanged
Key Area 4 - Properties of
Enzymes and Uses in Industries
Amylase enzyme
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
A
10 ml of
starch +
3ml of
amylase
enzyme
B
10 ml of
starch +
3ml of
water
Test Tube
Test Tube
Rack
Method
1.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.
Results
Iodine Solution
Test Tube
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
Starch
Amylase
and
starch
join
together
Enzyme can join
with another
substrate
molecule and
repeat the
reaction time
after time.
Amylase
(unchanged)
Enzyme
breaks
down the
starch
sugar
Conclusion
The starch is broken down into maltose by
the enzyme amylase.
Word Equation
ENZYME
Amylase
Starch
SUBSTRATE
Sugar
PRODUCT
Breakdown of Starch
Amylase
ENZYME
Starch
SUBSTRATE
Sugar
PRODUCT
Topic 4 - Properties of Enzymes
and Uses in Industries
Phosphorylase enzyme
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.
Glucose moving to roots to
be stored in potatoes
• Potatoes contain an enzyme called
phosphorylase which builds up starch
from glucose.
Activity 4 – Build up of glucose into
starch
Method
1
2
3
4
glucose + phosphorylase
A
glucose + water
B
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.
Results
Time
Row
0 mins
3 mins
6 mins
9 mins
A
glucose +
phosphorylase
B
glucose + water
Conclusion Potatoes contain an enzyme _______________ which builds
up glucose into _____________.
Glucose
Phosphorylase
SUBSTRATE
Starch
PRODUCT
Build Up Reaction
• A BUILD UP reaction occurs is when a
substrate with small molecules is joined
up into larger molecules.
Phosphorylase
Glucose
SUBSTRATE
Starch
PRODUCT
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 they
only fit with one substrate. Each substrate has a different
shape. Each enzyme also has a different shape.
Substrate 1 fits into enzyme
so reaction takes place.
Substrate 1
Substrate 2 does not fit
into enzyme so reaction
does not takes place.
Substrate 2
No reaction
Activity 5 – Which enzyme is
amylase?
Equipment
Enzyme bottles A, B and C
Bottle of starch
3 boiling tubes
Test tube rack
Measuring cylinder
3 syringes
Iodine solution
Labels
Activity 5 – Which enzyme is
amylase?
Method
1. 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
present or
absent?
Starch +
enzyme B
Starch +
enzyme C
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
You will set up the following experiment.
A
B
C
Test Tube
10ml of cold
hydrogen
peroxide and
detergent
10ml of
hydrogen
peroxide and
detergent
10ml of
hydrogen
peroxide and
detergent
+ frozen potato
+ normal
potato
+ boiled
potato
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 potato
Frozen potato
Normal potato
Boiled potato
Height of foam produced
(mm)
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
Even when cooled
down, the shape of
the enzyme does not
go back to normal, so
the enzyme is
permanently
destroyed.
Catalase and
hydrogen
peroxide
cannot join
together
No reaction
happens.
Topic 4 - Properties of Enzymes
and Uses in Industries
Detergents
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 nonbiological detergents.
Washing powders and liquids are
also called detergents.
Enzymes in Industry
•Enzymes can be used in industry.
•Biological detergents contain enzymes that are made
by genetically engineered bacterial cells.
•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.
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 & NonBio detergents
biological
washing
powder
A
non-biological
washing
powder
B
Water bath at 40oC
Stain on cloths
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
TestTube
Stain Detergent
A
Biological
B
Nonbiological
Result
Advantages of Biological
Washing Powders
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 using
biological detergents?
Disadvantages of Biological
Washing Powders
The enzymes in biological detergents can
cause allergic reactions such as eczema in
some people.
Allergic reactions
Topic 4 - Properties of Enzymes
and Uses in Industries
Cheese Making
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.
Cheese Making
An enzyme called rennet is used in the process of cheese making:
Making Cheese
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 from
a supermarket and it will
already be pasteurised!).
Pasteurising kills unwanted or
harmful bacteria as well as
giving milk a longer shelf life.
To pasteurise milk, heat it to 72oC
for 15 seconds then quickly cool to 5-10oC.
Making Cheese
Step 3:
Add a starter culture.
This contains bacteria that will convert the
lactose sugar in milk to lactic acid.
Starter culture (bacteria)
Acidic milk
Making Cheese
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=CJbPo7Hq
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http://www.youtube.com/watch?v=aImiN_8E
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Curds & Whey
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.
Curds
Whey
Making Cheese
Step 6
The curds are pressed in a mould and
then matured to form cheese.
The longer the curds are left
to mature, the stronger the cheese.
Cheese making
Making Cheese
Whey
A waste product that can be
used to make:
- sweeteners
- gels for processed meats
- alcoholic drinks ie. Baileys
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.
Where does rennet come from?
There are two types of
rennet used in cheese
making:
• Calf Rennet (from
calves’ stomachs)
• Genetically Engineered
Rennet (from fungus)
• 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 Making
1.
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.