S2 Biology
Peebles High School
booklet number
always take the booklet with your number on it
you are responsible for this booklet in class
Cells
Pupil Booklet
read information
think
mini white board activity
work sheet
work in your jotter
highlight
ICT
group work
Underlined Headings
should be written into
your jotter with the date
Practical work
Homework
1
S1 Cell Parts recap
On a mini white board draw two simple cells like the ones below
animal cell
plant cell
Try to label three parts on the animal cell and six parts of the plant cell.
Get a clue card from your teacher if you need help.
Enzymes
Your teacher will show you the following demonstration
Hydrogen peroxide
(H2O2)
Manganese dioxide
(black powder)
clue
H2O2
What did you see?
Can you explain what happened?
H2O + O 2
2
Copy into your jotter
Hydrogen peroxide (H2O2) will break down slowly into water (H2O) and
oxygen (O2). Adding a CATALYST like manganese dioxide will speed up this
break down. The catalyst speeds up the reaction without being used up itself.
Cells make proteins to speed up the reactions that take place in them. These
BIOLOGICAL CATALYSTS are called ENZYMES.
Enzyme
Equation
hydrogen peroxide
catalase
water + oxygen
Investigating Catalase
Hydrogen peroxide is a toxic substance made by cells. The cells deal
with it by making Catalase, an enzyme which speeds up the breakdown
of hydrogen peroxide into water and oxygen.
Using the following equipment plan an investigation
Aim - to find out how much catalase different living tissues contain.
 boiling tubes
 Hydrogen peroxide
 Detergent (washing up liquid)
[CLUE – the detergent will make a foam when bubbles of oxygen are produced]
 Carrot / apple / onion / liver / potato
 Stopwatch
 Measuring cylinder
What variable will you change (INPUT)? What variable will you measure for
your results (OUTPUT)? What variables will you keep the same? What safety
precautions must you take (CONTROLLED)?
Write down your ideas on a mini whiteboard and get them checked
by your teacher
Carry out the experiment.
Record your Results in a table with the following headings.
Type of tissue
height of foam (mm)
3
Use your results to draw a bar graph.
Make a list of success criteria, 5 or 6 things that make a good bar
graph.
Mark your partner’s graph using these success criteria.
Get your graph checked by your teacher then stick it into your jotter.
Conclusion – In your conclusion compare the enzyme content of the
different type of tissues based on the height of foam produced.
Extension - What effect did boiling have on the activity of the enzyme?
Now update your glossary.
Investigating Phosphorylase
The enzyme catalase is a BREAKDOWN enzyme. It speeds up a
reaction that breaks a large molecule into smaller ones. Enzymes can
also speed up SYNTHESIS or build-up reactions. In synthesis
reactions small molecules are built up into larger ones.
PHOSPHORYLASE is a synthesis enzyme that speeds up the reaction that
builds glucose-1-phosphate into starch (see diagrams below). It is found in
potatoes. The SUBSTRATE of phosphorylase is glucose-1-phosphate and the
product is starch.
This is a molecule of glucose
Below is part of a molecule of starch
Starch is made up a long chain of many glucose molecules joined together.
Phosphorylase speeds up the reaction that makes the starch molecule.
Enzyme
Equation
glucose-1-phosphate
phosphorylase
starch
4
Carry out the following experiment
1. Collect 3 test tubes, a test tube rack, 3 labels, 3 droppers, dimple
tile, stopwatch, Iodine,
You will share the glucose-1-phosphate, potato extract and distilled water
Do not cross contaminate the syringes or the droppers.
2. To test tube A add 2ml of Glucose – 1-phosphate and 2ml of potato extract.
3. To test tube B add 2ml of Glucose – 1-phosphate and 2ml of distilled water.
4. To test tube C add 2ml of distilled water and 2ml of potato extract.
5. Start the stopwatch.
6. Place a sample from each of the mixtures into one of the dimples in the
dimple tile every 5 minutes. Add Iodine to test if starch has been produced.
[NB. If Starch is present the iodine will change from brown to black]
Copy and complete this table to record your Results.
SAMPLE
0
Starch present?
5
Time after mixing (minutes)
10
15
20
A
G-1-P & potato extract
B
G-1-P & water
C
water & potato extract
Conclusion Describe what these results have shown about the effect of
phosphorylase on glucose-1-phosphate
Now update your glossary.
Enzyme Equations are a shorthand way of showing the reaction that an enzyme
speeds up. You have seen two so far and there is one more to come.
 The substrate is the molecule that the enzyme acts on and is written on
the left of the arrow.
 The enzyme is written above the arrow.
 The product is written on the right of the arrow.
Enzyme
Equation
substrate(s)
enzyme
product(s)
5
Investigating Amylase – The effect of Temperature on the activity of an
enzyme
Enzyme
Equation
starch
amylase
maltose
Plan an Investigation …
Aim To find out the effect of temperature on the activity of amylase.
Help – Remember…
 Input variable – the factor you are investigating; the only one that you
can change.
 Output variable – the factor that is affected by the input variable; the
one you measure for your results.
 Controlled Variables – all other factors that may affect the results and
must be kept the same to ensure a fair test.
- Hint
 Iodine will change colour from brown to black if starch is present.
Get your plan checked by your teacher. Collect the work card if you
need help. Carry out the experiment
Results
Collect the results table and stick it into your jotter
time
(min)
0
5
10
15
20
-2
starch present = √ starch absent = X
Temperature (◦C)
25
35
60
Conclusion In your conclusion describe the effect of changing temperature on
the activity of amylase.
6
Why does increasing the temperature increase the activity of the enzyme
but a high temperature decreases the activity of the enzyme?
 What happens to the enzyme between –2oC and 35oC to make it more
active?
HINT – What happens to the rate of collisions when you drive
faster on the Dodgems?
 What happens to the enzyme (a protein) above 35oC to make it less
active?
HINT - What happens to the protein in an egg white when you heat it?
Optimum conditions and Denatured enzymes
The higher the temperature the faster the molecules are moving. Fast
moving molecules will have more collisions than slow moving ones. Reactions
happen when molecules collide. Therefore as the temperature rises the enzyme
works faster. The condition where an enzyme works fastest is called the
OPTIMUM.
However at temperatures above 40oC the protein that the enzymes are made of
begins to change shape. The enzyme molecules no longer fit their substrates
and so cannot speed up the reaction. The enzyme is said to be DENATURED.
Collect the graph and stick it into your jotter. Update your glossary
7
Look back in this booklet to find the three Enzyme Equations write
them into your jotter. Label the two breakdown reactions and the one
synthesis reaction.
Highlight
them to make them stand out.
Specificity of Enzymes
A different enzyme is needed for each substrate. Amylase will only work
on starch, catalase will only work on hydrogen peroxide etc. This is
because when an enzyme acts on its substrate it temporarily binds with it. The
shape of the enzyme molecule must fit the shape of the substrate molecule.
This makes each enzyme specific for its substrate.
Look at the diagram below.
The key has a shape
that specifically fits
the lock.
The lock is changed
the key is unchanged
and can be used again.
The key and the lock
combine.
This is the
same for
enzyme action.
Enzyme-substrate
complex
Unchanged enzyme
Collect an enzyme action diagram and stick it into your jotter add the correct labels
and a description of the Lock and Key Theory of enzyme action.
Now update your glossary.
You may be given some resources to make models to show the lock and key
theory of enzyme action.
Amoeba Sisters Summary of enzymes
Homework sheet.
https://www.youtube.com/watch?v=XUn64HY5bug
8
EXTENSION TASK (does not need to be completed by all)
Collect a SG Biology Text Book
Read about the effect of pH on enzyme activity (p67-69 in Third Edition)
Write a report of the catalase experiment
Aim – To find out the effect of changing the pH on the activity of the enzyme
catalase.
Method – describe what was done
Results – draw a table of the height of the foam (just use your ruler to
measure it) then turn this table into a graph.
Conclusion – describe the effect of changing the pH on the activity of catalase.
Respiration
In the Ecosystem unit you learned about the flow of energy through
food chains. Plants make food and animals eat food in order to provide
energy for all living cells. RESPIRATION is the reaction, in cells, that releases
the energy from the food and like all biochemical reactions it is controlled by
enzymes.
Respiration Stations - In this activity you will find out
 Why cells need energy
 The raw materials for aerobic respiration
 The products of aerobic respiration.
There are 6 stations to complete
When you have completed the activity at one station check your
answers on the STATION SOLUTIONS SHEETS
Wait for your teacher’s instruction before moving to the next station.
Can you compete the aerobic respiration equation?
f_____ + o__________ ---> c_______ d_______ + w________ + e________
9
Diffusion
Try the following experiment to find out how molecules move into and
out of a cell by diffusion across a model cell membrane.
Set up this apparatus,
wash the visking
tubing bag thoroughly
before placing it in
the water.
Test tube
Visking tubing
Starch and glucose
solution
water
After 30 minutes
find out if the starch
and glucose have
moved from the inside of the visking tubing to the outside.
Use classroom resources to find out how to test for starch and
glucose.
Conclusion What do the results tell you about glucose, starch, the cell
membrane and diffusion?
DIFFUSION is the movement of a
substance from an area where it is
high in concentration to an area where
it is low in concentration. The difference in
concentration between the two areas is called
the CONCENTRATION GRADIENT.
The two types of raw material molecule for
aerobic respiration are FOOD (GLUCOSE) and
OXYGEN. They will enter the cell because, compared to the outside, there is a
lower concentration of them inside the cell.
The two types of product molecule for aerobic respiration are WATER and
CARBON DIOXIDE. They will leave the cell because, compared to the inside,
there is a lower concentration of them outside the cell.
Collect a Diffusion Cell diagram and use the information above to
complete it, then update your glossary.
10
Anaerobic Respiration
If there is NO OXYGEN available cells can still release some of the energy
from the glucose.
This type of respiration is called ANAEROBIC RESPIRATION. The products it
makes are different in yeast cells and animal cells. You may already know what
they are …..
Look at the pictures below for some hints…..
 In a 100m sprint the muscle cells respire anaerobically
…it is linked to this data
Lactic acid in blood mmol/l
Sometimes this happens…
Running speed km/h
 Yeast cells…
What makes bread rise?
…can make TWO useful products
when they respire
anaerobically …
What do these drinks have in common?
11
Anaerobic Respiration in Yeast
Carry out the following experiment
Collect
 2 small conical flasks
 0.5g yeast (x2)
 1g sugar
 50ml Warm water (x2) – NO HOTTER than 37oC
 2 Balloons
 Water bath at 37oC
Method
 Add the warm water, sugar and
Place in warm
water bath
yeast to one flask and mix
thoroughly.
 Add warm water and yeast (but
Yeast +
NO SUGAR) to the other flask
sugar solution
 Place a balloon over the neck of
each flask.
 Put the flasks into the water bath
Results What happens to the balloon? How could you test which gas is being
produced?
Anaerobic Respiration equations - Copy the following
In animal cells
In yeast cells
glucose
glucose
lactic acid
ethanol + carbon dioxide
Highlight the aerobic respiration and anaerobic respiration equations
Now update your glossary
12
Cell growth
New cells need to be made for reproduction of single celled organisms (e.g.
yeast) and for growth and repair of multicellular organisms (e.g. you).
Cell division is how these new cells are created.
Mother
cell
2 daughter
cells
Chromosomes are thread-like structures found inside the nucleus of every
living cell. The chromosomes are made of DNA and carry the genetic
information necessary for the survival of the cell.
chromosomes
2 daughter cells
Mother cell
Look at the diagram above.
1. How many chromosomes are in the mother cell?
2. How many chromosomes are in each daughter cells?
3. What is the first thing that happens to the mother cell?
4. What happens in the mother cell just before it divides into tow daughter
cells?
Stick the cell division diagram into your jotter and use these notes to
write a description of cell division in your jotter.
Your teacher may show you a short film about the stages of cell division. It
explains in more detail how cell division occurs but there is much more
detail in it than you need at this stage. https://www.youtube.com/watch?v=1hFtEqRdn_I
Homework sheet.
13
Uncontrolled Growth
 Illustration of normal cells dividing





 Illustration of uncontrolled multiplication of abnormal cells
The cluster of abnormal cells called a tumour is what causes Cancer.
Collect the diagram, stick it into your jotter and add labels.
Your teacher may show you a short film clip
From healthy cell to Cancer cell
http://www.youtube.com/watch?v+8LhQllh46yI
Or Introduction to Cancer Biology
http://www.youtube.com/watch?v+8LhQllh46yI
This is a good website if you want to find out more about Cancer
http://www.eschooltoday.com/cancer/cancer-facts-and-tips-for-kids.html
Your glossary should now be completed
TIME TO DO SOME REVISION….
Highlight the key words in your Learning Outcome Checklist
Revision / Extension Work
 Use the Standard Grade Biology Text Book [third edition]
 Read p62-65 answer questions on p65
 Read p50- 53 answer the questions on page 53
 Test Question Practice Booklet available
 Use a variety of study techniques to revise for the test e.g.
 Flashcards – look on http://www.hns.org.uk/bio/
 Make a mind map of the learning outcomes.
 Get someone at home to test you on the learning outcomes.
14