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Key Processes of Exchange     |     home
                                                  
Calvin-Benson Cycle



The Steps
CO2 combines with the phosphorylated 5-carbon sugar ribulose bisphosphate
This reaction is catalyzed by the enzyme ribulose bisphosphate carboxylase oxygenase (RUBISCO)(an enzyme which can fairly claim to be the most abundant protein on earth)
The resulting 6-carbon compound breaks down into two molecules of 3-phosphoglyceric acid (PGA)
The PGA molecules are further phosphorylated (by ATP) and are reduced (by NADPH) to form phosphoglyceraldehyde (PGAL)
Phosphoglyceraldehyde serves as the starting material for the synthesis of glucose and fructose
Glucose and fructose make the disaccharide sucrose, which travels in solution to other parts of the plant (e.g., fruit, roots)
Glucose is also the monomer used in the synthesis of the polysaccharides starch and cellulose