Process by which green plants and certain other organisms transform light into chemical energy.
In green plants, light energy is captured by chlorophyll in the ATP molecules. Oxygen, released as a by-product, passes into the atmosphere through pores in the leaves. NADPH and ATP drive the second stage, the dark reaction (or Calvin cycle, discovered by {{link=Calvin, Melvin">Melvin Calvin ), which does not require light. During this stage glucose is generated using atmospheric carbon dioxide. Photosynthesis is crucial for maintaining life on earth; if it ceased, there would soon be little food or other organic matter on the planet, and most organisms would disappear.