1. 13/07/2019
1.What do you need to stay alive?
2.What can provide the substances for life?
3.What do plants need to produce food?
Starter Activity MISSION – LIFE SUPPORT Write your answer (10 seconds) Pass paper to partner Write something different

2. 13/07/2019
Plants and Photosynthesis Explain why chlorophyll and light are necessary for photosynthesis Think creatively to produce a test for the presence of starch in a leaf

3. Things needed for photosynthesis
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SUNLIGHT
Gives the plant energy
CHLOROPHYLL
The green pigment where the chemical reactions happen
WATER
Travels up from the roots
CARBON DIOXIDE
Enters the leaf through small holes (stomata) on the underneath

4. Photosynthesis equations
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Sunlight
Carbon dioxide + water glucose + oxygen
(food)
6CO H20 C6H12O O2
Chlorophyll
Sunlight
Chlorophyll
Taken in through holes (stomata) in the leaves
Stored as starch in leaves, roots, stems
Taken in through the roots
Question – How do we know that light is needed for photosynthesis?

5. Method for starch test:
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1) Cover up part of the leaf using aluminium foil
What effect does this have on the plant?
Stops light reaching the leaf
2) Place leaf in boiling water [1 minute]
What does this do to the leaf?
to kill the cell and tear open the cell membranes so the iodine stain can easily enter the cells
Place leaf in boiling alcohol (ethanol) [5 minutes]
What effect does this have on the leaf?
to remove the green chlorophyll so the final results can be clearly seen

6. Method for starch test:
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4) Dip leaf into warm water
What effect does this have?
to remove the alcohol so the iodine stain can penetrate the leaf
5) Cover leaf with iodine solution to test for the presence of starch
What do you see? Draw and explain your results
Iodine turns starch blue-black
Those parts of the leaf that stain blue-black contain starch
Those parts that are yellow-brown (the colour of the iodine stain) do not have starch

7. Photosynthesis happens in the “palisade” cells in the leaf:
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Photosynthesis happens in the “palisade” cells in the leaf:
Palisade cells

8. Close up on a palisade cell:
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Cell wall
Cell membrane
Chloroplasts (containing chlorophyll)
Large vacuole
Nucleus
Cytoplasm

9. Chloroplast Chlorophyll
Photosynthesis summary
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Chloroplast
These are small structures that vary in number and size.
They contain a green pigment called chlorophyll.
LIGHT
Chlorophyll
The chlorophyll traps sunlight and uses this energy to drive the process of photosynthesis.
Photosynthesis is the name of the chemical reaction that produces the plant’s food.
Therefore, Chloroplasts are where a plant makes its own food.

10. NO LIGHT, NO PHOTOSYNTHESIS, NO STARCH!
Results:
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The parts of the leaf which have been photosynthesising should have turned black.
This shows that the part of the leaf which was covered up has not been photosynthesising, because it had no light.
NO LIGHT, NO PHOTOSYNTHESIS, NO STARCH!

11. TRUE or FALSE
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Both leaves turned blue-black because both leaves have been photosynthesising.
Only the leaf that had been in the dark turned blue-black because photosynthesis happens in the dark.
Starch is made in leaves that are photosynthesising. Photosynthesis only happens in the light.

12. TRUE or FALSE
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A positive test for starch in a leaf is that iodine solution turns blue-black.
Chlorophyll is a green pigment in plant cells that absorbs water.
Light is not needed for a plant to produce oxygen and glucose.
Light is essential for photosynthesis and provides the energy to drive the reaction.
Alcohol removes chlorophyll from the leaf so the results of the starch test can be clearly seen.
Plants make food (glucose) and oxygen which are essential for life.
I will make the mission a success because I know what is essential for photosynthesis.

13. 13/07/2019
Plants and Photosynthesis Explain why chlorophyll and light are necessary for photosynthesis Think creatively to produce a test for the presence of starch in a leaf

14. 13/07/2019

15. Root hair cells
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Plant roots are made of “root hair cells” which have two features that help them to take in water and nutrients:
Root hair cells
Large surface area
Thin cell membrane

16. Using light Plants need water to do the following: Produce glucose
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Plants need water to do the following:
Produce glucose
Enable transport of minerals
Form fruits
Enable growth
Keep the leaves cool

17. Photosynthesis and Respiration
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In earlier work we looked at respiration:
Glucose oxygen water carbon dioxide
Photosynthesis is the reverse of respiration:
Water carbon dioxide glucose oxygen