∞ generated and posted on 2016.08.25 ∞
Conversion of the energy of photons into chemical energy as mediated by various organisms.
The light reaction occurs within the context of photosynthesis. The resulting chemical energy is in the form of ATP as well as a product known as NADPH, which is a carrier of "reducing" electrons.
The light reaction occurs, as the name would suggest, only in the presence of light, and then only light of an appropriate wavelength. See by contrast the dark reaction of photosynthesis.
The light reaction is responsible for the generation of molecular oxygen (O2) by green plants, cyanobacteria, and eukaryotic algae, that is, generation of the oxygen that we breath.
The following video discusses how plants, algae, and cyanobacteria capture the energy from photons, to be later stored as organic molecules: