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Plants and Plants and PhotosynthesisPhotosynthesis

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Travels up from the roots

WATER

CARBON DIOXIDEEnters the leaf through small holes on the underneath

SUNLIGHTGives the plant energy CHLOROPHY

LL The green stuff where the chemical reactions happen

Things needed for Things needed for photosynthesisphotosynthesis

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Carbon dioxide + _____ glucose + _____

6CO2 + 6H20 C6H12O6 + 6O2

Sunlight

Chlorophyll

Sunlight

Chlorophyll

The GLUCOSE produced by photosynthesis is used by the plant for _______ (through ____________). It is stored in the plant as ___________.

Words – respiration, starch, water, oxygen, energy

Photosynthesis equationsPhotosynthesis equations

13/04/23Photosynthesis happens Photosynthesis happens in the “palisade” cells in in the “palisade” cells in

the leaf:the leaf:

Palisade

cells

13/04/23Close up on a palisade Close up on a palisade cell:cell:

Cell wall

Cell membrane

NucleusLarge vacuole

Cytoplasm

Chloroplasts (containing chlorophyll)

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Method for starch test:Method for starch test:

1) Cover up part of the leaf using black card

What effect does this have on the plant?

2) Boil the leaf for a few minutes

What does this do to the leaf?

3) Soak the leaves in alcohol

What effect does this have on the leaf?

4) Dip the leaves in water

What effect does this have?

5) Drop some iodine onto the leaf

What do you see? Draw and explain your results

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Results:Results:

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!

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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 cellsRoot hair cells

Root hair cells

Thin cell membrane

Large surface area

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Using waterUsing waterPlants need water to do the following:

Enable transport of minerals

Enable growth

Form fruits

Produce glucose

Keep the leaves cool

13/04/23Photosynthesis and Photosynthesis and RespirationRespiration

In earlier work we looked at respiration:

Photosynthesis is the reverse of respiration:

Glucose + oxygen water + carbon dioxide

Water + carbon dioxide glucose + oxygen