In the light reactions, light energy is turned into electrical then chemical energy by a series of pigment systems and transport proteins located in the membrane of the thylakoid. The final products of the light reactions include NADPH which carries electrons and hydrogen ions. These will then be transferred to organic molecules during the light independent or dark reactions. Another product of the light reactions, ATP produced by elecron transport phoshophorylation also powers some of the molecular rearrangements in the dark reactions. In addition oxygen is produced when water is split by a process called photolysis. This process yields oxygen, a waste as fao as the light reaction is concerned, electrons which replace those lost by the photosystems of the light reaction and hydrogen ions, many of which are passed to the dark reactions as part of NADPH.
pgd 02/18/00
revised 2/17/01