Photosynthesis that leads to the ultimate reduction of NADP to NADPH. In addition, this creates a proton gradient (energy gradient) across the chloroplast membrane, which is used by ATP synthase in the synthesis of ATP. The chlorophyll molecule ultimately regains the electron it lost when a water molecule is split in a process called photolysis, which releases a dioxygen (O) molecule as a waste product. The overall equation for the light-dependent reactions under the conditions of non-cyclic electron flow in green plants is: Not all wavelengths of light can support photosynthesis. The photosynthetic action spectrum depends on the type of accessory
Fractionation of carbon isotopes in oxygenic photosynthesis processes that selectively use one carbon isotope over the other, or "fractionate" carbon through kinetic or thermodynamic effects. Oxygenic photosynthesis takes place in plants and microorganisms through different chemical pathways, so various forms of organic material reflect different ratios of C isotopes. Understanding these variations in carbon fractionation across species is applied in isotope geochemistry and ecological isotope studies to understand biochemical processes, establish food chains, or model the carbon cycle through geological time. Carbon isotope fractionations are expressed in using delta notation of "δ"C ("delta thirteen C"), which is reported in parts per thousand (per mille, ‰). "δ"C is