The starting materials for photosynthesis are carbon dioxide, water and sunlight. Green plants have special cell structures called chloroplasts that contain a green pigment called chlorophyll. When chlorophyll is excited by sunlight in the presence of carbon dioxide and water, green plants are able to synthesize carbohydrates through photosynthesis.
Factors such as the intensity of light, the concentration of carbon dioxide in the air and the air temperature affect the rate of photosynthesis.
The initial stage of photosynthesis is dependent on light and as the intensity of light improves, the rate of photosynthesis quickens. Light in the wavelength range of 700 to 680 nanometers is best for the process. Photosynthesis involves a few enzymes and at a higher temperature the process is catalyzed by these enzymes. However, when optimum temperature is reached, the process begins to slow down.
Photosynthesis takes place in the leaves of only green plants and in certain photosynthetic bacteria, and it allows solar energy to enter the living ecosystems in the form of chemical energy. Green plants are called autotrophs or producers for this reason. Entire food chains and food webs are based on this characteristic of green plants being able to trap solar energy through photosynthesis. Oxygen is given out as a byproduct of photosynthesis. Thus, photosynthesis also ensures a natural balance of carbon dioxide and oxygen.