Photosynthesis

Plants make their own food by way of Photosynthesis. the process produces glucose. photosynthesis happens in leaves of all green plants.

Photosynthesis happens inside the chloroplasts. These are found in the green part of the leaf cell.
Chloroplasts contain chlorophyll, this absorbs sunlight, this is used to convert C02 and H20 into glucose and 02.

Carbon dioxide 6C02 + Water 6H20 -----> Glucose C6,H12,06 + 602

The equation shows that photosynthesis is important as it convert light energy to chemical energy, this energy is stored as glucose.

Leave structure.
Leaves are made of:
A Waxy cuticle.
Upper epidermis.
Palisade mesophyll layer.
Spongy mesophyll layer.
lower epidermis.
waxy cuticle.

The Waxy cuticle helps to reduce water loss by evaporation.
The upper epidermis is transparent so light can pass through to the palisade layer.
The palisade layer contains most of the chloroplasts, as it close to the leaf's surface they get most of the light.

The lower epidermis contains the stoma or stomata of the leaf, these small holes allow C02 to diffuse directly into the leaf. The stoma are protected by guard cells.

Rate of Photosynthesis.
This is dependant on three things.
The amount of Light, the amount of C02 and the temperature of its surroundings. Photosynthesis will slow down or stop in incorrect conditions.

C02.
Is a raw material of photosynthesis. As with light intensity, increasing the C02 concentration will increase the rate of photosynthesis, up to a point. Showing that C02 is no longer the limiting factor. As long as there is plenty of light and C02, then temperature must be the limiting factor.

Two main products of photosynthesis are glucose and oxygen.
The glucose is stored as starch by plants.

Before a leaf can be tested, its needs to be killed by dunking it in boiling water.
This stops any chemical reactions from taking place.

Once killed, heat the leaf in ethanol using a boiling tube and water bath.
this gets rid of the chlorophyll and leaves the leaf a whit-ish colour.

to test to prove chlorophyll is need for photosynthesis. Follow the same procedure for the starch test, kill, clean the leaf, but instead use a variegated green and white leaf.

The white part of the leaf contains no chlorophyll, the green part contains chlorophyll.

Remove a leaf from the plant after a while, and perform a starch test as previously outlined. The leaf should not turn blue-black, as no starch will have been produced through photosynthesis.

By performing a similar experiment where a plant has been kept away from light i.e in a cupboard, you can prove light is needed for photosynthesis.