WHAT IS IT?
Plants make their own food using sunlight. This is called photosynthesis.
It occurs when plants are exposed to light. The light is absorbed by the chlorophyll (found in chloroplasts) in some plant cells.
4 things are needed:
- Light from the sun Light
- CO2 from the air CO2 + Water = Glucose + Oxygen
- Water from the soil Chlorophyll
- Chlorophyll from the leaves
HOW PLANTS USE GLUCOSE
Glucose produced in photosynthesis can be:
- Changed into insoluble starch and stored in the stem or leaves
- Used by the plant during respiration to provide energy
Some glucose is:
- Used to produce fat or oil and stored
- Used to produce cellulose to cell walls
- Used to produce proteins
Glucose is a suger which is an important energy source in living organsims
FACTORS AFFECTING PHOTOSYNTHESIS
- CO2 concentration
- Light Intensity
1) As the temperature increases, so does the rate of photosynthesis. Temperature limits the rate of photosynthesis.
2)As the temperature approaches 45°the rate of photosynthesis drops to zero because the enzymes controlling photosynthesis have been destroyed.
1) As the rate of CO2 concentration increases, so does the rate of photosynthesis. CO2 limits the rate of photosynthesis.
2) After reaching a certain point, an increase in CO2 has no further effect. CO2 is no longer the limiting factor-it must be either light or temeprature.
1) As light intensity increases, so does the rate of photosynthesis. Light intensity limits the rate of photosynthesis.
2) After reaching a certain point, an increase in light intensity has no further effect. Light intensity is no longer the limiting factor-it must be either CO2 or temperature.
Greenhouses can be used as an artificial control of photosynthesis.
By controlling lighting, temperature and carbon dioxide, gardeners can increase the rate of photosynthesis.
This means plants:
- Can grow more quickly
- Can become bigger and stronger