SAMPLE PAGES FROM UNIT C
Heinemann Science Scheme
Teacher Resource Pack 3
ISBN: 0 435 58249 6
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This sample contains most of Unit C from Heinemann Science Scheme
Teacher Resource Pack 3 in a PDF format. Because this advance
material has not yet been through all checking stages, it may still
contain minor errors.
The following pages are not included in this sample material but will
be in the Pack: test-yourself answers; keywords lists and glossary lists.
© B. Dawson, 2002, The Heinemann Science Scheme
This material may be freely copied for institutional use prior to the publication of the book from which it is taken.
However, this material is copyright and under no circumstances may copies be offered for sale.
C1
How do plants
grow?
Learning objectives
(from QCA Scheme of Work)
Pupils should learn:
C
that green plants do not absorb
`food' from the soil
that green plants use carbon
dioxide and water to produce
biomass
the meaning of the terms
`photosynthesis' and `biomass'
to represent photosynthesis by a
word equation
that light is needed for
photosynthesis
that the raw materials for
photosynthesis are taken from
the environment around the
plant
to interpret and draw
conclusions from data
to decide how to measure the
rate of photosynthesis
to control variables
to present results in tables and
graphs, identifying anomalous
results
Teaching
activities
C1a Core:
How do plants
grow?
C1b Core:
Measuring the rate
of photosynthesis
Learning outcomes
(from QCA Scheme of Work)
Pupils:
Specials
Extension
resources
C1
How do plants
grow?
C1
How do plants
grow?
C1
Proving that
plants need
carbon dioxide
for
photosynthesis
(learning support)
1
Scheme of Work
B Dawson, 2002, The Heinemann Science Scheme
identify the source of raw
materials in photosynthesis
explain the terms
`photosynthesis' and `biomass'
provide some evidence that
plants do not obtain biomass
from the soil
construct the word equation for
photosynthesis
identify that the carbon dioxide
level is lower in daylight
explain this, eg the leaves are
using carbon dioxide during the
day
conclude that photosynthesis
takes place when there is
daylight
devise a way of measuring
photosynthesis, eg by timing the
collection of a fixed volume of
oxygen; by using an oxygen probe
describe how the rate of
production of oxygen varies
with light intensity
produce appropriate graphs of
their results and identify and
explain any anomalous results
Homework
resources
Unit C Plants and photosynthesis
Book
spread
2
B Dawson, 2002, The Heinemann Science Scheme
Learning objectives
(from QCA Scheme of Work)
Pupils should learn:
Teaching
activities
Learning outcomes
(from QCA Scheme of Work)
Pupils:
Homework
resources
Specials
(learning support)
Extension
resources
C2
What do plants
do with
glucose?
C2
What is the role
of the leaf in
photosynthesis?
to test for the presence of starch
in a leaf
to heat flammable liquid safely
that chlorophyll and light are
necessary for photosynthesis
that oxygen is produced during
photosynthesis
about variation between leaves
that leaves are adapted to
photosynthesise efficiently
how leaf cells close to the upper
surface are adapted for
photosynthesis
C2 Core:
Testing stencilled
and variegated
leaves for starch
C2 Help:
Testing stencilled
and variegated
leaves for starch
detect the presence of starch in
a photosynthesising leaf and
relate it to the presence of
chlorophyll
relate photosynthesis to the
exposure of the leaf to light, eg
etiolation
explain that oxygen released
from photosynthesis is used by
animals in respiration
describe differences between leaf
cells, and explain that those
close to the upper surface
photosynthesise effectively, eg
are long and thin, have many
chloroplasts
C2
What is the role
of the leaf in
photosynthesis?
C2
What is the role
of the leaf in
photosynthesis?
C3
What happens
to glucose
produced in
the leaves?
that plants store starch
that new materials made from
glucose produced during
photosynthesis lead to an
increase in biomass
that the glucose from
photosynthesis provides energy
for all living processes in the
green plant
to identify what information is
needed and use different texts as
sources
C3 Core:
What happens to
glucose produced
in the leaves?
C3 Help:
What happens to
glucose produced
in the leaves?
identify photosynthesis as the
source of biomass in plants
explain that glucose made in
photosynthesis is used for
respiration
describe all parts of the plant as
deriving from the products of
photosynthesis
select, compare and synthesise
information from different texts
C3
What happens
to glucose
produced in
the leaves?
C3
What happens
to glucose
produced in
the leaves?
Unit C Plants and photosynthesis
C
Book
spread
Scheme of Work
Learning objectives
(from QCA Scheme of Work)
Pupils should learn:
Teaching
activities
Learning outcomes
(from QCA Scheme of Work)
Pupils:
Homework
resources
Specials
(learning support)
C4a Core:
What is the role of
the root in
photosynthesis?
C4b Core:
Where does the
water go next?
explain the functions of water in
plants, eg in photosynthesis, to
transport minerals, to make the
plant firm, for cell growth, to cool
leaves, to form fruits
describe how roots are adapted
for taking in water, eg by being
spread out, being branched,
having a large surface area,
having root hairs
describe how the root hair cell is
adapted for its function
explain that root cells need
oxygen supplies in the soil for
respiration
suggest how substances from the
soil enter and move through the
plant
recognise that plants need
mineral salts for growth
relate a plant's need for nitrates
to making protein and hence
healthy growth
C4
Are green
plants
important?
(Note: this
homework is
preparation for
Activity C5)
C4
What is the role
of the root in
photosynthesis?
C5
Why are green
plants
important in the
environment?
that photosynthesis removes
carbon dioxide from the air and
produces oxygen
to consider the issues of
environmental protection from
several perspectives
to compare the word equations
for respiration and
photosynthesis
C5 Core:
Are green plants
important?
C5 Help:
Are green plants
important?
describe how carbon dioxide
and oxygen concentrations in
the air have varied over time
explain how photosynthesis and
respiration can help maintain
the balance of gases in the air
identify the main sources of
oxygen from photosynthesis
identify the advantages and
disadvantages of forest
conservation for a range of
people and other living things
C5
Why are green
plants
important in
the
environment?
C5
Why are green
plants
important in
the
environment?
B Dawson, 2002, The Heinemann Science Scheme
3
Scheme of Work
that roots are adapted to take in
water and this is used in
photosynthesis
that plants use water in many
ways
that roots require oxygen for
respiration
to make careful observations
and record these in drawings
that plants need sources of
nitrogen and other elements in
the form of minerals
that mineral deficiency hinders
plant growth
C
C4
What is the role
of the root in
photosynthesis?
Extension
resources
Unit C Plants and photosynthesis
Book
spread
Teacher and technician notes
How do plants grow?
Resources available
C1a
Materials required
Core sheet
How do plants grow?
CD-ROM
All resources customisable
For core (per group)
broad bean seed
digital balance
small beaker of warm water from the tap or
kettle
Links with
Book 3
SoW
Sc1
sheet of blotting paper
C1
9C page 1
2f, g, k±n
scissors
Safety
Do not allow students to use the oven.
Activity procedure
Core
1 Students weigh a dry broad bean seed before
soaking it in warm water for 40 minutes.
2 They allow the seed to germinate in water
and leave it to grow until it has produced at
least four large leaves that have turned dark
green.
3 They take the growing plant from the beaker
and weigh it. They are asked to explain where
the extra mass has come from.
Extension
There is an optional extension section at the foot
of the core sheet, which can be cut off if not
required. The plant is heated by the teacher in
an oven at 100 8C to drive off all the water.
Students then reweigh it and can see that it is
still heavier than the mass of the seed. They are
asked to draw a conclusion.
Running the activity
While the bean is soaking, the class could discuss
ideas about how the rate of photosynthesis
might be measured. These ideas can be used to
introduce Activity C1b.
It is most important that the plant is not
weighed until it has developed at least four dark
green leaves.
The dry mass will initially fall as the seed uses its
food reserves for respiration. It is only after the
seedling starts photosynthesising that the dry
mass increases.
250 cm3 beaker
water
Additional for extension (per class)
access to oven
Notes on materials preparation
It will take a couple of weeks for the broad bean
plant to grow sufficiently. The activity can be
structured so that it is revisited later in the unit.
Alternatively, with at least two weeks' advance
planning, plants can be prepared from weighed
seeds prior to the lesson.
Sample results
Core
The mass of the fresh plant will be greater than
that of the dry seed. More able students will say
that the increase in mass is due to the uptake of
water.
Extension
Although there is a weight reduction after
drying, the mass of the plant is still greater than
that of the original seed. More able students will
realise that the additional mass has come mainly
from the air (carbon dioxide).
Answers
1, 2 Students may come up with a variety of
answers but should be led to the conclusion
that the mass increase cannot be due to the
water (that has been dried off) so something
must have been absorbed from the air. This
can then lead on to a discussion of the role
of carbon dioxide in the air.
1
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B Dawson, 2002, The Heinemann Science Scheme
Teacher and technician notes
Measuring the rate of
photosynthesis
C1b
3 They repeat the procedure at different
Resources available
Core sheet
Measuring the rate of
photosynthesis
CD-ROM
All resources customisable
Links with
Book 3
SoW
Sc1
C1
9C page 1
2f, h±k, m
Safety
Warn students not to splash the hot lamp
with water as this could cause the glass to
implode.
Mercury vapour lamps give off small
amounts of ultraviolet light. Warn students
not to look directly at the lamp. Use a
shielded lamp if available.
Warn students that lamps get hot when in
use.
Low voltage electricity supplies for lamps
must be used.
Make sure there are no wet hands or water
near the power supply and plug.
Activity procedure
Core
1 The students are provided with the following
apparatus. It is set up with about 30 cm
between the weed and the bulb.
distances between the lamp and pondweed.
4 They use the results to plot a graph.
Extension
There is an optional extension section at the foot
of the core sheet, which can be cut off if not
required. Students take readings from their
graphs and consider the relationship between the
distance (light level) and the rate of
photosynthesis.
Running the activity
To introduce this activity, refer back to the
discussion about methods of measuring the rate
of photosynthesis in Activity C1a.
Mercury vapour lamps are expensive and it may
not be possible to have more than one setup. In
this case students can take turns to count, and
the teacher will need to decide when to increase
the distance between the lamp and pondweed.
Some students could start their initial recording
immediately and draw their full table of results
later.
Materials required
For core (per group)
1 dm3 beaker
filter funnel
boiling tube
250 W mercury vapour lamp with shield
pondweed (Elodea)
500 cm3 of sodium hydrogencarbonate
solution, 0.1%
watch or stopwatch
metre ruler
Elodea
0.1 % sodium
hydrogencarbonate solution
2 They measure the distance between the lamp
and the pondweed and record the number of
bubbles of oxygen liberated in 1 minute. The
number of bubbles is proportional to the rate
of photosynthesis.
2
C
B Dawson, 2002, The Heinemann Science Scheme
Notes on materials preparation
This practical is quite tricky, but the following
procedure should ensure good results.
1 Place the pondweed in a 0.1% solution of
sodium hydrogencarbonate rather than water
to ensure that sufficient carbon dioxide is
available for photosynthesis.
2 Bubble air through the solution using a
standard aquarium pump for at least 30
Continued
Teacher and technician notes
Measuring the rate of
photosynthesis continued
C1b
minutes. This is to ensure that the solution is
saturated with oxygen so that the oxygen
bubbles produced do not immediately
dissolve in the solution.
3 A suitable lamp with shield can be obtained
from Philip Harris Education.
Extension
More able students may be able to determine
that a pattern exists whereby the rate of
photosynthesis reduces by a quarter each time
the distance between the lamp and the
pondweed is doubled (the inverse square law).
Sample results
Answers
Core
It is almost impossible to isolate all the variables
for this experiment, particularly the state of the
Elodea. This means that results will vary.
However, the number of oxygen bubbles will
decrease as the lamp is moved further away,
showing that light is required for photosynthesis.
Students should also realise that the number of
bubbles indicates the rate at which
photosynthesis is proceeding.
1 As the distance increases, the number of
bubbles decreases.
2 As the light intensity falls, the rate of
photosynthesis falls.
3 Inverse square law
3
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B Dawson, 2002, The Heinemann Science Scheme
Teacher and technician notes
Testing stencilled and variegated
leaves for starch
Resources available
Materials required
Core sheet
Testing stencilled and
variegated leaves for starch
Help sheet
Testing stencilled and
variegated leaves for starch
CD-ROM
All resources customisable
For core and help (per group)
Bunsen burner
tripod, gauze and heatproof mat
250 cm3 beaker half full of water
white paper and pencil for diagrams
plant leaf, variegated or with a stencil
forceps
Links with
Book 3
SoW
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C2
9C page 2
2f, k±m
Safety
Eye protection must be worn.
Warn students to take care with the hot
water.
On no occasion should alcohol come close to
a naked flame. Ensure that all Bunsen
burners are extinguished before providing
students with alcohol.
Warn students that iodine will stain their
skin and clothing.
Activity procedure
Core and help
1 Some groups of students test a variegated leaf
for starch, and other groups test a normal
green leaf to which a stencil has been
attached. Make sure students know which
experiment their group is doing.
2 They find out that chlorophyll and light are
required by the plant in order to
photosynthesise.
boiling tube half full of alcohol
access to water bath at 90 8C
white tile
iodine in potassium iodide solution with
dropper
Notes on materials preparation
Geranium plants are ideal as both normal and
variegated varieties are available.
Setting up the experiment in advance is crucial to
its success. The leaves (variegated or with stencil)
need to be left attached to the plant in a dark place
for 24 hours, to de-starch. Then leave the plants for
a further 24 hours in a brightly lit area. Photoflood
lamps are ideal for this purpose. If the plants are
left in the dark and then used first thing the
following morning, the experiment will not work.
Sample results
Variegated leaves will turn black in areas that
were previously green, and brown in all other
(previously white) areas.
Stencilled leaves will turn black where light had
access to the leaf, and brown in all other areas.
Answers
The help sheet gives a flow chart to help students
visualise the process, and alternative structured
questions. This sheet can be given out in addition
to the core sheet to students who need it.
Core
1 The patterns match.
Running the activity
4 The shapes match.
Tell students that they need to make accurate
drawings of the leaves.
Students need to boil the leaf until it is soft
(about 1 minute). They also need to leave it in
the alcohol until it is completely decolorised (up
to 5 minutes).
4
C
B Dawson, 2002, The Heinemann Science Scheme
2 Green
3 Chlorophyll is needed for photosynthesis.
5 No, only the parts that received light turned
black.
6 Light is needed for photosynthesis.
Help
1 same, green, black, green
2 same, not covered, black, light
C2
Teacher and technician notes
What happens to glucose
produced in the leaves?
Resources available
C3
Materials required
Core sheet
What happens to glucose
produced in the leaves?
Help sheet
What happens to glucose
produced in the leaves?
CD-ROM
All resources customisable
For help (per group)
vegetable cooking oil
piece of wood
brown sugar
potato tuber
lavender oil
grains of rice
Links with
Book 3
SoW
Sc1
C3
9C page 3
2bij
Safety
Warn students not to taste any of the
substances.
Activity procedure
cotton fiber fibre or fabric (white)
Additional for core (per group)
starch powder
corrugated cardboard
piece of Quorn
access to library or computer connected to
the internet (optional)
Core and help
1 Students examine a range of plant materials.
They may also research other plant materials
from a library or the internet.
Notes on materials preparation
The materials can be stored in containers so that
they can be re-used on subsequent occasions.
2 They produce a poster showing the diversity
Help
Vegetable cooking oil comes from sunflower or
suitable alternative plants.
of materials produced by plants.
Running the activity
Answers
Core
Students look at the materials provided and then
research others. Some students could be asked to
make a presentation to the class based on their
posters.
Piece of wood comes from any suitable tree.
Help
As an alternative to the core sheet, the help sheet
provides a structured poster for less able
students.
Cotton fibre comes from a cotton plant.
Brown sugar comes from sugar cane.
Potato tuber comes from a potato plant.
Lavender oil comes from a lavender plant.
Grains of rice come from rice plants.
5
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B Dawson, 2002, The Heinemann Science Scheme
Teacher and technician notes
What is the role of the root in
photosynthesis?
Resources available
Core sheet
What is the role of the
root in photosynthesis?
CD-ROM
All resources customisable
Links with
Book 3
SoW
Sc1
C4
9C page 4
2fkmo
Activity procedure
1 Students examine the structure of mung bean
roots and try to determine how they are
adapted to absorb water.
2 They draw a diagram and label it.
Running the activity
Mung bean seedlings need to be grown in
advance.
Students need to treat the seedling with care to
avoid damaging it. This is especially true when
removing the root system from the vermiculite
and rinsing it under running water.
Materials required
Per group
Petri dish or small beaker containing mung
bean seedlings growing in vermiculite
access to running water
white tile
hand lens
6
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B Dawson, 2002, The Heinemann Science Scheme
Notes on materials preparation
Mung beans germinate very quickly depending
on the environmental conditions. It is important
for technicians to trial this experiment
beforehand to determine the time it takes to
produce seedlings with the correct amount of
growth. Seedlings are needed that have a good
root structure with root hairs, and this will take
several days.
Vermiculite has been chosen as the growth
medium as it is much easier for the students to
remove this from the growing roots than when
compost is used.
Sample results
The students should notice that the roots are
branching (so can find water in different areas)
and have many fine root hairs (which increase
the surface area for the absorption of water).
Answers
1 They are very fine and have a large surface
area to absorb lots of water.
C4a
Teacher and technician notes
Where does the water go next?
Resources available
Core sheet
CD-ROM
C4b
Running the activity
Where does the water go
next?
All resources customisable
Links with
The celery needs to be stood in ink in advance.
Tell students that they need to make accurate
drawings of the sectioned stem, and that they
need to take care when cutting the section.
Materials required
Book 3
SoW
Sc1
C4
9C page 4
2fhklm
Safety
Instruct students in the safe use of a sharp
scalpel or knife. Scalpel guards can be made
from a short piece of rubber tubing. If knives
are used they should be craft knives and
fitted with a guard.
Activity procedure
1 Students examine the leaves of celery that has
been standing in red ink. They should notice
that the veins of the leaves have been stained
red by the ink.
2 They remove a section from the petiole
(although technically inaccurate, this is
referred to as the stem). They observe that
the ink has been transported through specific
areas of the stem, rather than the whole stem.
This leads on to the idea that plants have a
transport system.
Per group
stick of celery standing in 250 cm3 beaker half
full of red ink
white tile
sharp scalpel or knife with guard
hand lens
Notes on materials preparation
The celery sticks should be fresh and placed into
the beakers of red ink 24 hours prior to the
experiment. It is important that the leaves
remain intact.
Sample results
The veins in the leaves turn red, indicating the
passage of the ink.
The section will show staining only in the areas
called xylem, which is the tissue responsible for
the transport of water up the stem.
areas stained
red
Answers
1 The stem is stained red only in small specific
areas. This must be where the water is
transported up the stem.
7
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B Dawson, 2002, The Heinemann Science Scheme
Teacher and technician notes
Are green plants important?
C5
3 Supplementary information may be handed
Resources available
out to each group (see help below).
Core sheet
Are green plants
important?
4 Allow the groups 15±20 minutes to prepare
Help sheet
Are green plants
important?
5 Standard debate format should be followed,
CD-ROM
All resources customisable
Spreadsheet for results for
graphing
Spreadsheet with data
ready provided
Links with
Book 3
SoW
Sc1
C5
9C page 4
1a, 2bdno
their cases.
as described on the core sheet.
6 A vote should then be taken.
Help
Additional information is provided for students
who need it. The help sheet could be used with
all groups in the class if preferred.
Running the activity
It is essential that the homework sheet C4 has
been given out during the previous lesson.
Activity procedure
Materials required
Core
1 Homework C4 provides preparation for this
activity. Students will have considered some of
the arguments for and against destroying the
rainforest.
Per group
sets of envelopes containing the additional
information for red and green groups
2 Divide the class into two groups, red and
green. Each group identifies two speakers and
a secretary to take notes.
8
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B Dawson, 2002, The Heinemann Science Scheme
Sample results
The verdict may vary and will depend upon the
debate that preceded it.
Activity
How do plants grow?
C1a
Core
Aim
To understand that plants do not grow by absorbing soil
from their surroundings.
Equipment
broad bean seed
digital balance
small beaker of warm water
sheet of blotting paper
scissors
250 cm3 beaker
water
access to oven
What to do
1 Weigh a dry broad bean seed on a digital balance.
Record the mass.
2
Soak the broad bean seed in warm water in a small
beaker for 40 minutes.
3
Cut the blotting paper so that it is the same height as
the beaker. Roll it up and place it inside the beaker.
4
Pour about 2 cm depth of water into the beaker.
5
Take out the soaked bean and place it so that it rests
between the beaker and the blotting paper, about 2 cm
above the surface of the water.
6
7
blotting paper
broad bean
Leave the broad bean to grow for about two weeks.
You will need to make sure there is always some water
in the bottom of the beaker. Alternatively, your teacher
may give you a broad bean that has already been
growing like this.
water
When the bean has grown and produced green leaves,
carefully remove the bean from the beaker and weigh it
again.
Question
1 Compare the new mass with the original mass and
discuss this with your group. Where you think the
increase in mass came from?
Extension
8 Your teacher will place the plant in an oven and heat it
until all of the water has been driven off.
9
Reweigh the plant again and compare this new mass
with the previous two masses.
Question
2 What conclusion can you draw from this experiment?
1
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B Dawson, 2002, The Heinemann Science Scheme
Activity
Measuring the rate of
photosynthesis
C1b
Core
Aim
To measure the rate of photosynthesis by counting the
number of oxygen bubbles released from pondweed.
Equipment
Your teacher will give you the apparatus set up as in the
diagram. The pondweed should be photosynthesising
and giving off tiny bubbles of oxygen.
You will also need:
watch or stopclock
The lamp will get very hot.
Do not splash water on to
the lamp or stare directly at
it.
metre ruler
What to do
1 Draw a table like the one below ready to record your results.
2 Place the lamp 30 cm away from the pondweed, and write this distance in your table.
3 Count the oxygen bubbles given off in one minute. Take three readings like this
and record the results.
4 Calculate the average number of bubbles given off in one minute.
5 Move the lamp a further 20 cm away from the pondweed. Record the distance
from the pondweed and repeat steps 3 and 4.
6 Continue moving the lamp away from the pondweed in steps of 20 cm. Each time
record the distance and repeat steps 3 and 4. Stop the experiment when the lamp is
1.5 m away from the pondweed.
7 Draw a graph of your results to show the effect of the distance between the lamp
and pondweed on the number of oxygen bubbles produced.
Results
Distance from
light to
pondweed (cm)
Number of bubbles of oxygen per minute
Reading 1
Reading 2
Reading 3
Average number
of bubbles per
minute
Questions
1 What do you notice about the effect of distance on the number of bubbles of
oxygen produced?
2 If the light intensity decreases as you move the lamp further away, what conclusion
can you draw about the need for light by the process of photosynthesis?
Extension
8 Use your graph to determine the number of bubbles of oxygen given off at the
following distances of the light source:
a 20 cm
b 40 cm
c 80 cm.
3 What pattern do you notice in your results?
2
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B Dawson, 2002, The Heinemann Science Scheme
Activity
Testing stencilled and variegated
leaves for starch
C2
Core
Aim
To find the conditions required for a leaf to photosynthesise.
Equipment
Bunsen burner
tripod and gauze
heatproof mat
250 cm3 beaker half full
of water
Wear eye protection.
Take care with hot water.
access to water bath
white tile
iodine solution with
dropper
plant leaf, variegated or
with a stencil attached
forceps
boiling tube half full of
alcohol
What to do
1 Put a beaker about half full of water on a tripod and gauze. Heat it with a Bunsen
burner till it is boiling.
2
Your teacher will provide you with a leaf. Half the class will have a variegated leaf
(this is a leaf of more than one colour). The other half will have a leaf with a
stencil attached. If your leaf has a stencil attached, do not remove it.
variegated leaf
green leaf
paper clip
black stencil
L
3
While the water is heating, make a clear pencil drawing of your leaf. Show the outline
of the different colours if it is variegated, or the position and shape of the stencil.
You are now going to test the leaf for starch. Starch will be present in the leaf where
photosynthesis has taken place.
4
First remove the stencil if there is one. Then use forceps to place the leaf into the
beaker of boiling water and leave it there for about 2 minutes. This will break
down the cell walls and make the leaf go floppy.
5
Switch off the Bunsen burner and carefully remove the leaf with
the forceps. The water and steam will still be very hot, so take care.
6
Place the crumpled leaf into a boiling tube half full of alcohol.
7
Put the boiling tube into the water bath. Leave it until the leaf turns
white. Take care again as the water will be very hot.
Alcohol is very flammable.
Do not have it anywhere
near a Bunsen burner flame.
The hot alcohol will dissolve the green chlorophyll out of the leaf. The leaf will turn
white.
Continued
3
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Activity
Testing stencilled and variegated
leaves for starch continued
C2
Core
8
Carefully remove the leaf with your forceps and briefly dip it into
the hot water in the beaker to rinse it. The leaf will go soft.
9
Place the leaf on your white tile. Carefully spread it out and
add several drops of iodine solution.
10
Leave the leaf for a couple of minutes and then make a clear pencil drawing of
what you can see. Compare this with your original drawing.
Iodine solution will stain
your hands and clothing.
Questions for variegated leaves
1 What do you notice about the pattern that was on the leaf and the areas of the leaf
that have stained black?
2 What was the original colour of the part of the leaf that stained black?
3 The black stain shows the places where the leaf made starch by photosynthesis.
What does this experiment tell you about the role of the green pigment called
chlorophyll?
Questions for stencilled leaves
4 What do you notice about the shape of the stencil and the areas of the leaf that
have stained black?
5 The stencil prevented light getting to some parts of the leaf. Did any of these
covered parts stain black?
6 The black stain shows the places where the leaf made starch by photosynthesis.
What does this tell you about the role of light in photosynthesis?
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Activity
Testing stencilled and variegated
leaves for starch
C2
Help
Aim
To find the conditions required for a leaf to photosynthesise.
Equipment
Bunsen burner
tripod and gauze
heatproof mat
250 cm3 beaker half full
of water
access to water bath
white tile
iodine solution with
dropper
plant leaf, variegated or
with a stencil attached
forceps
boiling tube half full of
alcohol
What to do
Use this help sheet after you have carefully read and understood the instructions on
the core sheet.
The following diagrams will help you carry out your experiment.
First, remove the stencil from the leaf if it has one.
Wear eye protection.
Take care with hot water.
Put leaf in boiling water
for 2 minutes to break
down cell walls.
Alcohol is very flammable.
Do not have it anywhere
near a Bunsen burner flame.
Put leaf in hot alcohol
in a boiling tube placed
in a hot water bath
until the leaf turns
white. Then dip in hot
water to rinse.
Iodine solution will stain
your hands and clothing.
Add iodine solution
to leaf.
Draw a diagram of the
leaf and label what you
see.
Continued
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Activity
Testing stencilled and variegated
leaves for starch continued
C2
Help
Question for variegated leaves
1 Use the following words to complete the sentences below about the activity that
you have just done. You may use each word once, more than once or not at all.
black
brown
dark
different
green
light
same
The pattern of the leaf and the pattern of the area that stained black were both
the
. The original colour of the part of the leaf that turned
black was
. Starch turns
when
iodine solution is added. This shows me that the
pigment
called chlorophyll is needed for photosynthesis to take place in the leaf.
Question for stencilled leaves
2 Use the following words to complete the sentences below about the activity that
you have just done. You may use each word once, more than once or not at all.
black
covered
dark
different
not covered
same
green
light
The shape of the stencil and the pattern of the area that stained black were both
the
. The stencil prevented light getting to some parts of
the leaf. The areas of the leaf that turned black were those areas that were
by the stencil. Starch
turns
that
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B Dawson, 2002, The Heinemann Science Scheme
when iodine solution is added. This shows me
is needed for photosynthesis to take place in the leaf.
Activity
What happens to glucose
produced in the leaves?
C3
Core
Aim
To find out what happens to the glucose produced in the
leaves by photosynthesis.
Equipment
vegetable cooking oil
piece of wood
brown sugar
potato tuber
lavender oil
grains of rice
cotton fibre or fabric
starch powder
corrugated cardboard
piece of Quorn
Do not taste anything in
the lab.
What to do
Your teacher will show you a range of materials produced
by plants. All these materials are made from the glucose
produced by photosynthesis.
1
Examine the materials and try to imagine how each
one started from simple glucose.
2
Use secondary sources such as the library or the
internet to research these and other important plant
products. Investigate such things as what plant
produces them and what the materials can be used for.
3
Your task now is to produce a large poster to present
details of your research, showing the economic
importance of plants and plant products.
You may wish to consider these ideas:
Your poster should be large and colourful.
Drawings should be clear and well spaced.
Lines and arrows can be used to link things
together.
Magazines can be used to provide colourful pictures
that can be cut and pasted.
4
When your poster is finished, your teacher may ask
some of you to use your poster as the basis of a
presentation to the class about what you have
discovered.
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Activity
What happens to glucose
produced in the leaves?
C3
Help
Aim
To find out what happens to the glucose produced in the leaves by photosynthesis.
Equipment
vegetable cooking oil
piece of wood
brown sugar
potato tuber
lavender oil
grains of rice
cotton fibre or fabric
Do not taste anything in
the lab.
What to do
1 Look at the things that your teacher has given you. Each one is made by a plant.
2
In the spaces below, draw a picture of each one. Use colour on your pictures if you
wish. There are extra spaces for you to draw in some ideas of your own.
3
When you have completed your drawings, find out which plant each substance
comes from. Label your drawings with the names of the plants. Your teacher may
allow you to use the internet or text books to help you with your research.
4
Try to think of a good title for your poster.
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Activity
What is the role of the root in
photosynthesis?
C4a
Core
Aim
To understand that a plant's roots are adapted to absorb water.
Equipment
Petri dish or small beaker containing vermiculite and germinating mung bean seeds
access to running water
white tile
hand lens
What to do
1 Your teacher will give you a small dish containing germinating seeds.
pieces of
vermiculite
mung beans
small dish
water
2
Carefully remove one of the seedlings and gently shake off any pieces of vermiculite
(vermiculite looks like small pieces of polystyrene). You may need to gently rinse
the seedling under running water.
3
Carefully place the seedling on a white tile and carefully observe the roots using a
hand lens.
4
Make a large clear labelled drawing of the roots.
Questions
1 What features do you notice about the roots that would make them efficient at
absorbing water?
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Activity
Where does the water go next?
C4b
Core
Aim
To understand that water passes up the stem of a plant.
Equipment
stick of celery standing in 250 cm3 beaker half full of red ink
white tile
sharp scalpel or knife with guard
hand lens
What to do
1 Your teacher will provide you with a beaker of red ink
containing a stick of celery. The celery has been
standing in the ink for the last 24 hours.
2
Look carefully at the leaves of the celery. What do you
notice?
3
Place the celery on a white tile. Use a sharp knife or
scalpel to cut across the celery twice to remove a
section approximately 1 cm thick.
cut here
4
Place the cut section on your white tile and make a
large clear labelled drawing of what you can see. Your
outline should look a bit like this.
Questions
1 What conclusions can you make about how the water
travels up the stem of the celery?
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Take care using a sharp
scalpel or knife. Replace the
guard between use.
Activity
Are green plants important?
C5
Core
Aim
To debate the importance of green plants in the environment.
What to do
Your teacher will put you into one of two groups.
Red group: you will be taking the role of cattle farmers
bordering the tropical rainforest in South America.
You need to cut and burn the rainforest in order to
grow grass for your cattle.
Green group: you will be taking the role of scientists
who are monitoring the effects on the environment of
destroying the rainforests.
1
As a group, discuss the results of your homework and
make a list of as many ideas to support your case as
possible.
2
You will need a secretary to take notes and two
speakers to speak on behalf of your group. As a group,
choose these three people.
3
Your teacher may give you a sealed envelope with
some extra information. You may choose to use it or
ignore it when you make your case.
4
Spend 15±20 minutes preparing your case. Remember
that you have two speakers so you will need to share
out some of the ideas.
The debate
5 Your teacher will ask for the first speaker from each group
to come out and present their case. The secretary should
take notes about what the other group is saying. Your
second speaker will then be able to speak about these
points and answer them when it is their turn to speak.
6
After each group has had their turn, you will be given a
five-minute break to consider the other group's
arguments.
7
The second speaker will then speak from each group to
sum up all the main points.
The jury
8 When all the speaking has finished, you are free to
change your mind based on what you have heard from
each of the groups. Your teacher will ask for a show of
hands to see whether you agree that the rainforests
should be destroyed to support the local cattle farmers.
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Activity
Are green plants important?
C5
Help
Aim
To debate the importance of green plants in the environment.
To provide additional information for students.
The sheet should be cut up and the parts given only to the relevant group.
........................................................................................
Red group
There is not much work available in your village. A local cattle farmer is cutting down
rainforest and burning it. He then allows the grass to grow on the fertile ground and
puts his cattle to feed on the grass. You are poor and need the money to feed your
family. The farmer offers you a job that you desperately need. Without the job your
family will starve.
You also know that rich western countries are burning millions of tonnes of oil each
year that release carbon dioxide into the atmosphere. You are angry that they expect
you to starve to save the environment, while they are destroying the environment so
they can maintain their luxurious lifestyle.
........................................................................................
Green group
Weather patterns around the world are changing. There are more storms and sea
levels are rising due to global warming. The latest data shows yet another rise in
atmospheric carbon dioxide levels. You know that the rainforests are needed to
absorb some of this carbon dioxide.
Some small islands in the South Pacific will drown in the near future, with possible
loss of life, as the sea levels rise.
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Homework
How do plants grow?
C1
1 Read the passage below and then answer the questions that follow.
Where do plants get their food?
Two thousand years ago, a Greek philosopher called Aristotle thought plants grew by absorbing
all their food from the soil. If this idea was correct, a plant in a flower pot would eventually use
up all the soil and fall over.
Clearly this idea of Aristotle's cannot be correct. The problem was that Aristotle did not know
about the gases in air. Today we know that the air contains carbon dioxide, but it is still
difficult for us to imagine that a wooden table we are working on was made by a plant, out of
carbon dioxide from the air and water from the soil.
a Explain what was wrong with Aristotle's ideas concerning plant growth.
b Suggest why Aristotle could not arrive at the correct answer.
c Explain where plants do get the material that they need to grow.
2 Copy and complete the following word equation to show what happens when
plants photosynthesise.
carbon dioxide 1 water
1
3 In order for plants to photosynthesise, they need energy.
Explain where plants get this energy from.
4 What happens to the process of photosynthesis at night? Explain your answer.
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Homework
What is the role of the leaf in
photosynthesis?
C2
1 Copy the boxes below. Draw a line to link each process in an experiment with the
correct reason why it is carried out.
Process carried out
Reason for process
the leaf is boiled in alcohol
to show whether light is required for
photosynthesis
a stencil is placed on a leaf
to show whether starch is present
the leaf is boiled in water
to remove chlorophyll
iodine solution is added to the leaf
to break down the cell walls
2 Look at the following diagrams of cells found in a normal leaf.
Copy each diagram and then choose the correct label to write underneath to
describe what the cell does.
yy
yy
palisade
cell
This cell has a large
surface area and is
surrounded by air spaces.
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spongy
cell
This cell covers the upper
and lower surfaces of the
leaf.
epidermal
cell
Packed with chloroplasts,
this cell is found close to
the upper surface, to trap
sunlight.
Homework
What happens to glucose
produced in the leaves?
C3
Plants produce glucose as food for respiration. However, they produce much more
glucose than they need. Plants convert this spare glucose into a variety of different
forms of biomass, which causes the plant to grow.
Use a range of secondary sources such as books and the internet to research some of
the biomass substances and materials produced by plants. Try to find some specific
examples, as well as general uses.
Here are some suggestions to include in your research:
various types of food
natural dyes
drugs used in medicine
construction industry
clothing
animal foods
fuel
decoration
furniture
alcoholic drinks.
........................................................................................
Homework
What happens to glucose
produced in the leaves?
C3
Plants produce glucose as food for respiration. However, they produce much more
glucose than they need. Plants convert this spare glucose into a variety of different
forms of biomass, which causes the plant to grow.
Use a range of secondary sources such as books and the internet to research some of
the biomass substances and materials produced by plants. Try to find some specific
examples, as well as general uses.
Here are some suggestions to include in your research:
various types of food
natural dyes
drugs used in medicine
construction industry
clothing
animal foods
fuel
decoration
furniture
alcoholic drinks.
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Homework
Are green plants important?
Rather than asking questions on work you have done in class, this homework is to
prepare for your next science lesson.
You will need two highlighter pens ± red and green. (If you do not have highlighters,
underline using felt-tip or ballpoint pens.)
Your task is to read the following arguments about whether the rainforest should be
cut down. Some people think that it is vital to cut it down to preserve local
communities. Other people think that it will do irreversible environmental damage.
You should read each argument and mark it with a highlighter pen based on the two
different points of view about whether the forest should be destroyed or preserved.
Red: mark the argument in red if you think it would be one put forward by a local
farmer who needs the land for cattle.
Green: mark the argument in green if you think it would be put forward by a
scientist who thinks that cutting down the forest will damage the environment.
Arguments
Green plants put oxygen back into the atmosphere.
Local farmers need grassland for their cattle.
Burning wood returns carbon dioxide to the atmosphere.
Tropical rainforests provide the most diverse habitat on the planet.
When farmers cut and burn the rainforest, the nutrients from the ash allow new
grass to grow.
Green plants remove carbon dioxide from the atmosphere.
Destroying the forest will kill many animals.
The rainforests are a source of plant material for the production of new medical
drugs.
An increase in carbon dioxide leads to global warming.
The rainforests are a major source of wood production to supply the building
industry.
Cattle release methane, which is another gas that causes global warming.
You may use the library or internet to research further information on this topic.
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C4
Homework
Why are green plants important in
the environment?
C5
Look at the following examples of ways in which we can
conserve our resources and reduce the amount of carbon
dioxide that we put into the atmosphere.
Suggest the advantages and disadvantages of each one and
explain how it would reduce the amount of carbon
dioxide being released into the atmosphere.
Example 1
Power stations produce electricity by burning fossil fuels
such as coal and oil.
Power stations can now be built to burn willow wood.
Willow is very fast growing and willow trees can be
grown and harvested each year. The tree is cut to near
ground level, but within a year it has grown again to
produce a fresh crop of wood for the power station.
Example 2
Timber can be harvested for the building industry from
forests that are replanted as soon as the timber is cut
down. This means that the forest does not get any
smaller, but produces a regular crop of good quality
timber.
Example 3
Electricity can be produced from alternative sources of
energy. For example, giant windmills have been built in
areas where it is often windy. These `wind farms' generate
electricity without producing any carbon dioxide.
Example 4
The construction industry can switch from using wood to
using other materials such as plastic and concrete.
Example 5
Energy-efficient machinery is now readily available. For
example, washing machines can now be purchased that
use much less electricity for each washing cycle. Cars can
be made to travel many more miles per litre of petrol.
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Specials
How do plants grow?
C1
s
t
r
a
c
t
a
s
n
m
i
b
o
l
f
o
c
a
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b
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n
d
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e
t
h
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d
b
i
o
c
f
s
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r
s
n
g
w
p
o
t
q
d
m
d
k
t
h
l
g
i
x
n
z
o
h
l
u
s
s
u
n
l
i
g
h
t
k
q
m
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c
b
c
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a
f
o
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t
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f
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e
y
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r
y
o
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s
q
h
f
r
z
j
x
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o
n
e
y
s
v
w
e
w
z
t
k
d
q
l
v
p
n
x
y
u
1 Fill in the gaps, and circle the missing words in the grid.
a Leaves make a sugar called
g
b Plants do not grow by absorbing
c Plants absorb
.
s
c
out of the ground.
d
out of the
air, to grow.
d Plants get their energy from
s
e Plants absorb water through their
.
r
.
f Photosynthesis is the process that plants use to make their
f
.
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Specials
What is the role of the leaf in
photosynthesis?
C2
1 A student tested a leaf for starch.
The following diagrams show what the student did.
Unfortunately they are all mixed up.
Find the drawing of the first thing the student did.
Then draw arrows to link each thing that the student did in turn.
L
2 Complete the passage using these words:
alcohol
black
cell wall
iodine
light
The leaf was boiled in water to break down the
.
The chlorophyll was removed by placing the leaf in hot
When
made turned
solution was added, the starch that the leaf had
.
The part of the leaf covered by the stencil did not contain starch. This proves that
the leaf needs
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for photosynthesis.
.
Specials
What happens to glucose
produced in the leaves?
C3
1 The jigsaw shows some of the uses of plants.
Cut out the shapes and make the jigsaw.
When you have made it, you can stick it onto a clean sheet of white paper.
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Specials
What is the role of the root in
photosynthesis?
C4
`Build a root' kit
You have been provided with parts of a drawing of a root.
Cut out the drawings along the dotted lines and use them to build a root system for a
plant.
Stick the pieces onto a clean sheet of white paper.
When you have built the root, cut out the labels and stick those onto the sheet.
Draw lines from the labels to the root.
........................................................................................
Labels
long tap root to anchor
the plant and get water
from deep in the soil
wide shallow roots to get
surface water and
support the plant
branching roots to give a
large surface area to
absorb water
root hairs to give large
surface area
g
d
un
o
r
r
su
fac
e
........................................................................................
ground surface
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Specials
Why are green plants important in
the environment?
C5
1 Read the following statement about plants and animals.
Use the information to answer the following questions.
Plants make food such as glucose by the process of photosynthesis. They do this by taking in
carbon dioxide from the air and giving out oxygen. This is very useful for animals like us. It
provides us with the oxygen that we need to breathe. We in turn breathe out carbon dioxide
that we make from respiration.
Use the following words to complete the word equations for photosynthesis and
respiration.
You may use each word more than once.
carbon dioxide
oxygen
Photosynthesis
1 water
glucose 1
Respiration
1 glucose
1 water
2 What do you notice about the two word equations for photosynthesis and
respiration?
3 Suggest why it is not a good idea for us to continue to chop down all the trees in
the world's forests.
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Extension
Proving that plants need carbon
dioxide for photosynthesis
C1
You are going to design an experiment to show that leaves need carbon dioxide to
photosynthesise.
You are provided with the following theoretical pieces of equipment.
two glass jars
You are also provided with the following information:
Soda lime absorbs carbon dioxide.
Leaves produce glucose by photosynthesis.
Leaves convert spare glucose into starch.
Leaves can be tested to see if they contain starch.
Air contains carbon dioxide.
1 Use the equipment shown and the information provided to design an experiment
to show that leaves need carbon dioxide for photosynthesis.
You should remember to control all the variables and to make your experiment a
fair test.
2 Write down instructions for the experiment to tell someone exactly how to carry it
out, and draw diagrams showing how the equipment is to be set up.
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Extension
What do plants do with glucose?
C2
1 Plants make glucose by photosynthesis. The formula for glucose is:
C6H12O6
Plants use glucose as the starting point for making many other substances. They
can join two molecules of glucose together to make one molecule of sucrose. The
formula for sucrose is:
C12H22O11
Sucrose is the kind of sugar that you put in a cup of tea.
The equation below shows how plants make one molecule of sucrose from two
molecules of glucose. However, when they do this, they also make something else.
C6H12O6 1 C6H12O6
C12H22O11 1 ?
Count the numbers of each kind of atom on both sides of the equation and work
out what the missing substance is. Choose from the following:
CH4 methane
CO2 carbon dioxide
H2O2 hydrogen peroxide
H2O water
2 Once plants have made sucrose, they can join sucrose molecules together to make
other substances such as starch.
Use the internet or sources from your library to find out about starch.
Imagine that you are trying to explain what starch is to someone who has no
knowledge of science or biology whatsoever. Make a list of what you think are the
five most important points about starch, to help you when you explain to this
person.
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Test yourself
Plants and photosynthesis
Unit C
1 Complete these sentences by crossing out the wrong words.
a Plants do/do not take in soil from the ground as they grow.
b During photosynthesis plants take in water through their leaves/roots.
c Plants also take in carbon dioxide/oxygen to make glucose.
2 Complete the following word equation for photosynthesis.
1 water
1 oxygen
3 The following steps were carried out by a student who was doing an experiment to
see if light is needed for photosynthesis. The steps are in the wrong order.
Write a number next to each step to show its correct order.
Boil the leaf in hot alcohol.
Place a stencil on a leaf.
Add iodine solution to the leaf.
Leave the leaf in the light for 24 hours.
Place the leaf in boiling water.
Remove the stencil.
Make a note of whether the leaf turns black.
4 Draw lines to match up each process with the correct reason for doing it.
Process
Reason
boil the leaf in water
turns black if starch is present
boil the leaf in alcohol
breaks down the cell walls
add iodine solution
dissolves out the chlorophyll
Continued
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Test yourself
Plants and photosynthesis
continued
Unit C
5 Complete the sentences below. Choose from these words to fill in the gaps. You
may use each word once, more than once or not at all.
chlorophyll
increases
light
oxygen
respiration
upper
As the amount of light increases, the rate of photosynthesis
.
The rate of photosynthesis in some water plants can be determined by counting the
number of
bubbles given off. The oxygen that is given
off is breathed in by animals and used for
green pigment called
. Plants use a
to carry out the process of
photosynthesis. Most photosynthesis takes place in the cells in
the
part of the leaf, because they receive
more
.
6 Put a tick against the following substances if you think they are made from
biomass of plants.
plastic
wood
cotton
rubber
nylon
starch
Continued
2
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B Dawson, 2002, The Heinemann Science Scheme
Test yourself
Plants and photosynthesis
continued
Unit C
7 The diagram shows the different parts of a plant. However, the labels are missing.
Complete the label boxes by copying out the correct descriptions from the boxes
below.
branched and have a
large surface area for
taking in water
small cells through
which water is absorbed
and nutrients diffuse
into the plant
Glucose is made here by
photosynthesis using
water from the roots
and carbon dioxide
from the air. It is the
source of all biomass in
the plant.
air spaces contain
oxygen that the roots
need for respiration
carries water up the
plant to the leaves for
photosynthesis
Continued
3
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Test yourself
Plants and photosynthesis
continued
Unit C
8 Complete the sentences below to describe the effects of plants on the environment.
Choose from these words to fill in the gaps. You may use each word once, more
than once or not at all.
constant
rising
falling
Photosynthesis and respiration together ensure that the level of carbon dioxide in
the atmosphere is
. However, because modern societies
burn a lot of fuels, the level of carbon dioxide is
.
Cutting down and burning rainforest is also responsible
for
levels of carbon dioxide. Only by reducing the
amount of fuel that we burn and conserving the rainforests can we
ensure
photosynthesis
Rate of reaction
9 The graph shows
both the rate of
respiration and the
rate of photosynthesis
in a flowering plant.
levels of carbon dioxide.
respiration
midnight
4 a.m.
8 a.m.
midday
4 p.m.
8 p.m.
midnight
Time of day
a During what period of time is photosynthesis faster than respiration?
b At which two times does the rate of photosynthesis equal the rate of respiration?
c Explain how the graph shows that photosynthesis produces far more glucose
than will be used up by the process of respiration.
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End of unit test
Plants and photosynthesis
Unit C
Tier 3±6
1 Write out two things from the following list that a plant uses to make food.
l starch
l water
l oxygen
l glucose
l light
(2 marks)
2 Look at the list below. From where does a plant obtain:
a carbon dioxide?
b water?
air
fertiliser
minerals
soil
(1 mark)
(1 mark)
water vapour
3 In which part of the plant does each of the following processes take place?
a absorption of water
(1 mark)
b photosynthesis
(1 mark)
4 Rita's class was asked to write down the word equation for photosynthesis.
Four of the different answers produced by the class are listed below.
A
B
C
D
oxygen 1 glucose carbon dioxide 1 water
oxygen 1 water carbon dioxide 1 glucose
carbon dioxide 1 water glucose 1 oxygen
oxygen 1 carbon dioxide water 1 glucose
a Which was the correct equation for photosynthesis?
b Which was the correct equation for respiration?
(1 mark)
(1 mark)
5 Peter examined the leaves of a plant he had grown.
He noticed the leaf had various features.
Explain how each of the features below enables leaves to carry out their
function.
a a large surface area
b green
(1 mark)
(1 mark)
Continued
1
C
B Dawson, 2002, The Heinemann Science Scheme
End of unit test
Plants and photosynthesis
continued
Unit C
Tier 3±6
6 When the plant had grown, Peter carefully
removed it from the soil.
He looked at the root structure and noticed
several features.
a Explain how each of the features below enables
roots to absorb water.
(3 marks)
i a branching structure
ii a large deep root
iii many tiny, long thin root hairs
b Why do plants need to take up nitrates through
their roots?
(1 mark)
7 Plants produce biomass. Biomass can be useful to us in many
different ways. One example is sugar from sugar cane.
a Name one other use of biomass.
b What is the name of the process by which a plant produces biomass?
(1 mark)
(1 mark)
8 Respiration is the process in which living things break down molecules
of glucose to release energy.
a Four different statements about the difference between photosynthesis
and respiration are given below. Which two are correct.
(2 marks)
A Photosynthesis uses light energy, respiration releases energy.
B Photosynthesis uses water and oxygen, respiration releases water
and oxygen.
C Photosynthesis does not need chlorophyll, respiration needs
chlorophyll
D Photosynthesis produces glucose, respiration uses glucose.
b State the source of the energy for the process of photosynthesis
(1 mark)
c Describe how you would test a sample of biomass to show the
presence of starch.
(1 mark)
2
C
B Dawson, 2002, The Heinemann Science Scheme
End of unit test
Plants and photosynthesis
Unit C
Tier 5±8
1 Peter examined the leaves of a plant he had grown. He noticed the leaf
had various features.
Explain how each of the features below enables leaves to carry out their
function.
a large surface area
b green
(1 mark)
(1 mark)
2 When the plant had grown, Peter carefully
removed it from the soil.
He looked at the root structure and noticed
several features.
a Explain how each of the features below enables
roots to carry out their function.
(2 marks)
i a branching structure
ii tiny root hairs
b Why do plants need to take up nitrates through
their roots?
(1 mark)
3 Rita's class was asked to write down the word equation for photosynthesis.
Four of the different answers produced by the class are listed below.
A
B
C
D
oxygen 1 glucose carbon dioxide 1 water
oxygen 1 water carbon dioxide 1 glucose
carbon dioxide 1 water glucose 1 oxygen
oxygen 1 carbon dioxide water 1 glucose
a Which was the correct equation for photosynthesis?
b Which was the correct equation for respiration?
c Raymond did an experiment to measure what two substances were
absorbed by a plant in order to photosynthesise. To explain what
happens in photosynthesis, he decided to write a symbol equation.
He wrote down some of the chemical formulae, but failed to
complete the equation.
Copy and complete Raymond's equation:
(1 mark)
(1 mark)
(2 marks)
1 6CO2 C6H12O6 1
Continued
3
C
B Dawson, 2002, The Heinemann Science Scheme
End of unit test
Plants and photosynthesis
continued
Unit C
Tier 5±8
4 Plants produce biomass. Biomass can be useful to us in many different
ways. One example is sugar from sugar cane.
a Name one other use of biomass.
b What is the name of the process by which a plant produces biomass?
(1 mark)
(1 mark)
5 Respiration is the process in which living things break down complex
molecules such as starch to release energy.
a Describe two ways in which this process differs from photosynthesis. (2 marks)
b State the source of the energy for the process of photosynthesis.
(1 mark)
c Describe how you would test a sample of biomass to show the presence
of starch.
(1 mark)
6 a Plant cells in the root are adapted to absorb water from their immediate
surroundings.
Explain how having a long thin hair-like shape helps a root to absorb
water.
(1 mark)
b Palisade cells in the leaf are adapted for photosynthesis.
Describe two features that help a palisade cell to photosynthesise.
(2 marks)
i contain large numbers of chloroplasts
ii situated near the upper surface of a leaf
7 Plants require carbon dioxide for photosynthesis and produce oxygen
as a waste product. The carbon dioxide diffuses into the leaf through
small holes on the under surface and oxygen diffuses out.
Explain what effect you think the following changes would have on the
rate at which photosynthesis takes place:
cuticle
upper
epidermis
palisade
mesophyll
layer
xylem in
vascular
bundle
(vein)
spongy
mesophyll
layer
lower
epidermis
chloroplast
stomata
a an increase in the level of atmospheric carbon dioxide
b a decrease in the amount of chlorophyll in the leaf cells
4
C
B Dawson, 2002, The Heinemann Science Scheme
(1 mark)
(1 mark)
Mark scheme
Plants and photosynthesis
Question
Part
Answer
Mark
Level
Water
Light
1
1
3
3
a
Air
1
4
b
Soil
1
4
a
Roots
1
4
b
Leaves
1
4
a
carbon dioxide 1 water
1
6
b
A or oxygen 1 glucose
1
6
a
Can absorb more carbon dioxide or light or get rid of
more oxygen
1
5
b
Contains chlorophyll to trap energy from sunlight or
contains chlorophyll for photosynthesis
1
5
ai
ii
iii
To reach many parts of the soil
To get to water deep down or to reach the water table
Give a large surface area for absorption
1
1
1
5
5
5
b
To grow or make proteins
1
5
a
Any suitable example, eg wood for burning
1
5
b
Photosynthesis
1
6
a
A and D
1, 1
6
b
Light or sunlight or the Sun
1
5
c
Add iodine solution ± the starch in biomass turns black
1
5
1
2
3
4
5
6
7
8
Unit C
Tier 3±6
Scores in the range of:
glucose 1 oxygen
carbon dioxide 1 water
Level
x±x
x±x
x±x
x±x
1
C
B Dawson, 2002, The Heinemann Science Scheme
Mark scheme
Plants and photosynthesis
Question
Part
Answer
Mark
Level
1
a
Can absorb more carbon dioxide or light or
get rid of more oxygen
1
5
b
Contains chlorophyll to trap energy from sunlight or
contains chlorophyll for photosynthesis
1
5
ai
ii
To reach many parts of the soil
Give a large surface area for absorption
1
1
5
5
b
To grow or make proteins
1
5
a
C or carbon dioxide 1 water
glucose 1 oxygen
1
6
b
A or oxygen 1 glucose
carbon dioxide 1 water
1
6
c
C6H12O6 1 6O2
6H2O 1 6CO2
(one mark for H2O and O2 in correct space, one mark for
balancing correctly, no marks for only one correct without
balancing)
2
7
a
Any suitable example, eg wood for burning
1
5
b
Photosynthesis
1
6
a
Any two from:
Photosynthesis uses light energy or water or carbon
dioxide; respiration releases energy or produces water
or produces carbon dioxide
Photosynthesis produces glucose or oxygen; respiration
uses glucose or oxygen
Photosynthesis needs chlorophyll; respiration does not
need chlorophyll
2
6
b
Light or sunlight or the Sun
1
6
c
Add iodine solution ± the starch in biomass turns black
1
6
a
Gives a large surface area compared with its volume
1
7
bi
ii
Lots of chloroplasts
Cells situated near upper surface of leaf
1
1
7
7
a
Rate of photosynthesis would increase (more reactant
for the reaction)
1
8
b
Rate of photosynthesis would decrease (more product
from the reaction)
1
8
2
3
4
5
6
7
Scores in the range of:
Level
x±x
x±x
x±x
x±x
2
C
Unit C
Tier 5±8
B Dawson, 2002, The Heinemann Science Scheme
Student record sheet
Plants and photosynthesis
Unit C
I can
do this
very
well
I can
do this
quite well
I need to
do more
work on
this
I know that plants use carbon dioxide and water for
photosynthesis
I can construct a word equation for photosynthesis
I know that leaves need light and chlorophyll to photosynthesise
I am able to carry out a starch test on a leaf
I can measure the rate of photosynthesis
I am able to use tables of data to produce graphs of
photosynthesis
I know how a leaf is adapted to photosynthesise
I understand that respiration and photosynthesis are in balance
I know that biomass increases because of photosynthesis
I know that glucose can be converted into starch for storage
I understand that glucose can be made into many different
substances by plants
I know how roots are adapted to their function of absorbing
water and minerals
I know that a plant uses nitrates to convert glucose into
proteins
I understand the importance of conserving the rainforests
I understand the importance or reducing carbon dioxide
emissions from burning fossil fuels
What I enjoyed most in this unit was
The most useful thing I have learned in this unit was
I need to do more work on
1
C
B Dawson, 2002, The Heinemann Science Scheme