Photosynthesis

Photosynthesis

Photosynthesis is the process by which plants convert solar energy from the sun into useful chemical energy for food. They release molecular oxygen and remove CO2 (carbon dioxide) from the air. Plants are photoautotrophs which means they are able to synthesize food directly from inorganic compounds using light energy, instead of eating other organisms or relying on material derived from them. The energy for photosynthesis comes from absorbed photons found in light and involves a reducing agent, in this case water. Oxygen is released as a product. All the organisms that undergo photosynthesis convert CO2 to organic material by reducing this gas to carbohydrates. This is done through a rather complex set of reactions. The pigments that absorb the light are primarily chlorophylls and carotenoids. Chlorophylls absorb blue and red light while carotenoids absorb blue-green light, but green and yellow light are not effectively absorbed by photosynthetic pigments in plants; therefore, light of these colors is either reflected by leaves or passes through the leaves. This explains why plants are green. Chlorophyll is also unique in that it is capable of converting the active energy of light into a latent form that can be stored and used when needed. In plants that undergo photosynthesis, water is absorbed by the roots and carried to the leaves by the xylem. CO2 is obtained from the air that enters the leaves through the stomata and diffuses to the cells containing chlorophyll.