Fractionation of carbon isotopes in oxygenic photosynthesis product 3-phosphoglycerate is depleted in C due to the kinetic isotope effect of the above reaction. The overall C fractionation for C3 photosynthesis ranges between -20 to -37‰. The wide range of variation in delta values expressed in C3 plants is modulated by the stomatal conductance, or the rate of CO entering, or water vapor exiting, the small pores in the epidermis of a leaf. The δC of C3 plants depends on the relationship between stomatal conductance and photosynthetic rate, which is a good proxy of water use efficiency in the leaf. C3 plants with high water-use efficiency tend to
Photosynthesis the newly formed NADPH and releases three-carbon sugars, which are later combined to form sucrose and starch. The overall equation for the light-independent reactions in green plants is Carbon fixation produces the intermediate three-carbon sugar product, which is then converted into the final carbohydrate products. The simple carbon sugars produced by photosynthesis are then used in the forming of other organic compounds, such as the building material cellulose, the precursors for lipid and amino acid biosynthesis, or as a fuel in cellular respiration. The latter occurs not only in plants but also in animals when the energy from plants is