Photosynthesis Coursework

BIOLOGY

Coursework

Photosynthesis

Made By: Mike Alexander=

Definition:

Photosynthesis is a process by which plants make their own organic, complex food (glucose) from organic, simple, raw materials using sunlight energy (which is converted to chemical energy) and enzymes in the chloroplasts (mainly mesophyll cells called palisade cells).

How It Works:

Carbon Dioxide + Water  Glucose + Oxygen

6CO2 + 6H2O  C6H12O6 + 6O2

- Water from the soil travels (by osmosis) through root hair cells to the xylem vessels then passes into the mesophyll cells (palisade) to the chloroplasts.

- Carbon dioxide from air diffuses into leaves through stomata then it moves through air spaces to reach the mesophyll cells then to the chloroplasts.

- Chlorophyll (inside chloroplasts) traps sunlight energy and this powers the photosynthesis reaction.

- The light energy splits H2O into hydrogen and oxygen (photolysis) called Light Stage.

- Hydrogen Combines with CO2 to make glucose Dark Stage requires no light and O2 is released through stomata to air (waste product).

* Light Stage: It is limited by light, not by temperature as enzymes are not involved.

* Dark Stage: It is limited by temperature since enzymes are involved and not light because it occurs in the dark.

Factors Affecting Photosynthesis:

Limiting Factors

Limiting Factor is any factor which is in short supply and leads to reduction of the rate of the process from its possible maximum and limiting the effect of other factors on rate of a reaction..

The Limiting Factors Are: 1- Light Intensity

2- Carbon Dioxide

3- Temperature

4- Factors Closing Stomata

5- Lack of Magnesium (Mg)

The more the light intensity, carbon dioxide concentration, temperature the more the photosynthesis rate up to a limit.

If all factors (light, CO2 concentration, temperature) are increased and the rate of photosynthesis is still