The Greek roots of photosynthesis combine to produce the basic meaning "to put together with the help of light". Photosynthesis is what first produced oxygen in the atmosphere billions of years ago, and it is still what keeps it their. Sun light splits the water molecules (made of hydrogen and oxygen) held in a plant's leaves and releases the oxygen in them into the air. The leftover hydrogen gets combined with carbon dioxide to produce carbohydrates, which the plant uses as a food- as do any animals are human beings who might eat these plants.

We can say photosynthesis is the process by which green plants and other organisms transform light energy into chemical energy. During photosynthesis in green plants, light energy is capture and uses to convert water, carbon dioxide, and minerals into oxygen and energy-rich organic compounds. Energy produced by photosynthesis carried out by plants millions of years ago is responsible for the fossil fuels (i.e. coal, oil and gas) that power industrial world. In past ages, green plants and small organisms that feed on plants increased faster than they were consumed, and their remains were deposited in Earth's crust by sedimentation and other geological processes.

Mechanism of Photosynthesis

In chemical terms, photosynthesis is a light-energized oxidation-reduction process. (Oxidation refers to the removal of electrons from a molecule; reduction refers to the gain of electrons bio a molecule) in plant photosynthesis, the energy of light is used to drive the oxidation of water (H₂O), producing oxygen (O₂), hydrogen ions (H⁺) and electrons. Most of the removed electrons and hydrogen ions ultimately are transferred to carbon dioxide, which is reduced to organic products. Other electrons and hydrogen ions are used to reduce nitrate and sulfate to amino and sulfhydryl groups in amino acids! which are the building blocks of proteins. In most green cells, carbohydrates-starch and sugar sucrose- are the major organic products of photosynthesis