During plant photosynthesis, 2 equivalents of glycerate 3-phosphate (GP; also known as 3-phosphoglycerate) are produced by the first step of the light-independent reactions when ribulose 1,5-bisphosphate (RuBP) and carbon dioxide are catalysed by the rubisco enzyme. The GP is converted to D-glyceraldehyde 3-phosphate (G3P) using the energy in ATP and the reducing power of NADPH as part of the Calvin cycle. This returns ADP, phosphate ions Pi, and NADP+ to the light-dependent reactions of photosynthesis for their continued function.
RuBP is regenerated for the Calvin cycle to continue.
G3P is generally considered the prime end-product of photosynthesis and it can be used as an immediate food nutrient, combined and rearranged to form monosaccharide sugars, such as glucose, which can be transported to other cells, or packaged for storage as insoluble polysaccharides such as starch.