The process in which certain carbohydrates are synthesized from carbon dioxide and water by chlorophyllous cells in the presence of light, oxygen being the byproduct is generally called photosynthesis. The summary equation for photosynthesis is
6 CO2 + 12 H2O + Solar energy → C6H12O6 + 6 O2 + 6 H2O
By the use of water and Carbon dioxide labeled with isotope oxygen biochemists have been able to demonstrate that the oxygen released in photosynthesis comes not from Carbon dioxide but from water.
Photosynthesis is an anabolic process in which green plants or green parts of the plants synthesize or manufacture complex carbonaceous organic food substances carbohydrates with carbon dioxide and water in the presence of sunlight and evolve oxygen as a byproduct .Thus in this process radiant energy is converted into chemical energy.
The green plants apart from taking nutrients from soil,make their own food by utilizing carbon dioxide, water and sunlight. This is the basis of photosynthesis. During this process oxygen is evolved and released to the atmosphere.
During photosynthesis carbon dioxide is chemically reduced to carbohydrate. Water molecule splits in presence of sunlight. This process is called photolysis and oxygen is released.
Importance of photosynthesis: Food is the source of energy needed by animal and plant life. And this food is manufactured by green plants from inorganic substances with the aid of sunlight energy during photosynthesis. Food represents the stored energy of sunrays. Fuel in the form of wood is also the indirect result of photosynthesis activity of plant and it is also thought that coal, petroleum etc. are also the remote consequences of photosynthesis.