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 RuBisCO-dependent cell growth rate, and the cell geometry and surface area. The use of bicarbonate and carbon concentrating mechanisms in phytoplankton distinguishes the isotopic fractionation from plant photosynthetic pathways. The difference between intracellular and extracellular CO concentrations reflects the CO demand of a phytoplankton cell, which is dependent on its growth rate. The ratio of carbon demand to supply governs the diffusion of CO into the cell, and is negatively correlated with the magnitude of the carbon fractionation by phytoplankton. Combined, these relationships allow the fractionation between CO and phytoplankton biomass to be used to estimate the phytoplankton growth rates.