1. PLANTS AND PHOTOSYNTHESIS
In This Section We Will Be Studying The Following Topics:
Photosynthesis and Respiration.
Factors affecting photosynthesis.
The leaf in close up.
Specialist cells and tissues.
The roots and their role.
Chlorophyll.
Plant adaptations.
Plant nutrients.
What happens to the products of photosynthesis.
Energy storage in plants.

2. Plants photosynthesise - but why? Which one do you agree with?
WHY PHOTOSYNTHESISE?
Plants photosynthesise - but why?
Plants photosynthesise to make food. They use sunlight as energy.
Plants are also called producers because they produce their own food.
Plants photosynthesise but they can also respire.
This means they can make food even when there is no sunlight.
This is partly right as plants do respire.
They can not photosynthesise when there is no sunlight. They stop making glucose.
Which one do you agree with?

3. Plants use photosynthesis to make their own food.
Oxygen
Released into
the atmosphere.
Light
From the sun
Glucose
For biomass
and energy.
Carbon dioxide
From the air.
Water
From the soil.
Plants use this glucose for respiration.

4. WHAT GOES WHERE? Light Glucose Oxygen Water Carbon dioxide
The reactants and products are very important in photosynthesis, but which are which? Sort the things listed below into the correct category.
REACTANTS
PRODUCTS
Light
Glucose
Oxygen
Water
Carbon dioxide

5. WHAT GOES WHERE? Light Glucose Oxygen Water Carbon dioxide
The reactants and products are very important in photosynthesis, but which are which? Sort the things listed below into the correct category.
REACTANTS
PRODUCTS
Light
Glucose
Oxygen
Water
Carbon dioxide

6. WHAT IS IT USED FOR? Glucose is made during photosynthesis.
This is a sugar.
Plants use glucose for the following things:
Respiration.
Making cellulose for cell walls.
Making starch stores.
Making proteins for growth and repair.
Making fats and oils for storage.

7. Let us look at the two equations.
BALANCE
Let us look at the two equations.
PHOTOSYNTHESIS
Carbon Dioxide +
Water
Sunlight
Glucose
Oxygen
RESPIRATION
Oxygen +
Glucose
Energy
Carbon Dioxide
Water

8. Photosynthesis and respiration work in a cycle.
IT’S A CYCLE
Photosynthesis and respiration work in a cycle.
Photosynthesis.
Continual Process.
Carbon dioxide
in the air.
Oxygen
in the air.
Respiration.
This happens inside plant cells.

9. LEAVES Leaves are specially adapted for photosynthesis.
They contain a green pigment called chlorophyll.
This absorbs the light energy for photosynthesis.
The leaf provides a large surface area for photosynthesis.
It is thin and its shape means that oxygen and carbon dioxide can easily move through it.
The chlorophyll is kept inside tiny structures called chloroplasts.
Stacks of chloroplasts inside the plant cells. They are found at the top of leaves.
Why are they at the top of the leaf?
This is where the sunlight hits the leaf.

10. LEAVES
The cells at the top of the leaf (Palisade cells) are in columns beside each other and they are packed with chloroplasts. These absorb the light energy.
These cells are supplied with water from the spongy cells inside the leaf, the mesophyll cells.
These cells also surround air spaces inside the leaf so they are able to exchange the gases. They also have some chloroplasts.
Spongy cells can hold water and gases.

11. LEAVES
The cells on the lower surface of the leaf are covered with holes called STOMATA. The Stomata can open and close to let gases move in and out of the leaf.
Stomata
Special bundles of cells make up a tissue called XYLEM that allows water to travel into the leaf from the roots.
Another specialist tissue called PHLOEM allows the sugars that are made to flow around the plant.

12. XYLEM and PHLOEM
These are the specialist tissues that allow substances to move around a plant.
XYLEM is for WATER.
PHLOEM is for SUGARS.

13. ROOTS Think about all of these features.
The roots are also specially adapted for their function.
They are very long so that they can stretch throughout the soil. This also gives the plant support.
They have special cells with a large surface area for the absorption of water. These are called root hair cells.
Think about all of these features.
What do you think a root hair cell would look like?
Draw one.

14. HOW CLOSE WERE YOU? Root Hair Cell:
The surface area is very large. It allows the plant to absorb water around the root hair cell.
Water moves into the plant.
It moves up the Xylem tissue to the leaves where it is used for photosynthesis.

15. LEAF SHAPE
When there is not much water in a habitat a plant will try to keep hold of any water it gets.
This happens with Marram grass on sand dunes.
The leaves curl into tubes to stop water loss.
In Cacti the leaves are the spikes and the juicy stem holds the water.

16. PLANT NUTRIENTS
The plant’s roots do not just absorb water from the soil but also minerals.
These minerals are needed for healthy growth.
Farmers and gardeners have known this for thousands of years and they put plenty of these minerals into the soil to help the plants grow well.
They use manure.
They use bones that are ground up for specialist plants. They also use blood when planting out new plants. This is an ORGANIC product.
These products are called FERTILISERS and they contain several different chemicals which plants need.

17. FERTILISERS
In farming the amount of fertiliser needed for a field is massive.
A good general fertiliser will contain the following MINERALS:
POTASSIUM –K- Helps in the production of flowers and flowering of fruit crops.
NITROGEN - N – Helps to make the proteins which are important for growth.
PHOSPHORUS – P- Helps to produce a healthy root and stem.
MAGNESIUM -Mg-
Helps in the production of chlorophyll.

18. ENERGY STORES IN PLANTS
It is often easier to think of these as the parts of the plant that animals like to eat.
Stems and leaves are not as high in energy as roots.
They are often high in protein or starch.
These are the reserves the plant uses for respiration.
Tubers and roots.
These are stores of starch/ glucose.
Nuts and seeds.
These are stores of fats/oils.

19. Work out what words these letters should spell.
KEY WORDS
Work out what words these letters should spell.
Phtsynthss
Rsprtn
xygn
Crbn dxd
Glcs
Rt hr cll
Plsd cll
nrgy
Chlrplst

20. KEY WORDS ANSWERS Photosynthesis. Respiration. Oxygen. Carbon dioxide.
Glucose.
Root hair cell.
Palisade cell.
Energy.
Chloroplast.

21. CHECK YOUR LEARNING. Science Questions. Photosynthesis is how plants:
a release carbon monoxide into the air.
b release oxygen into the air.
c release carbon dioxide into the air.
Root hair cells:
a absorb energy from the soil.
b absorb water from the soil.
c absorb carbon dioxide from the soil.

22. CHECK YOUR LEARNING. Science Questions.
Gases diffuse out of the leaf through the:
a palisade cells.
b stomata.
c root hair cells.
4. To increase the rate of photosynthesis you need to:
a increase light intensity.
b decrease carbon dioxide availability.
c decrease light intensity.

23. CHECK YOUR LEARNING. Science Questions. a having a large surface area.
5. Leaves are adapted for photosynthesis by:
a having a large surface area.
b having lots of cells.
c having a large gas supply.
6. The balance of oxygen and carbon dioxide in the air is maintained by:
a animals using oxygen for respiration and releasing carbon dioxide. Plants use this carbon dioxide.
b oxygen taken in by plants in photosynthesis, plants
release carbon dioxide and animals use this for
photosynthesis.

24. CHECK YOUR LEARNING- ANSWERS.1. 2. 3. 4. 5. 6.
c release carbon dioxide into the air.
b absorb water from the soil.
b stomata.
a increase light intensity.
a large surface area.
a animals using oxygen for respiration and release carbon dioxide. Plants use this carbon dioxide.