gluconeogenesis UPa:UPA00138 GO:0006094 Gluconeogenesis is the generation of glucose from other organic molecules like lactate, glycerol, and amino-acids. Many 3- and 4-carbon substrates can enter the gluconeogenesis pathway. But the first designated substrate in the gluconeogenic pathway is pyruvate. Gluconeogenesis cannot be considered to be a reverse process of glycolysis, as the three irreversible steps in glycolysis are bypassed in gluconeogenesis. This is done to ensure that glycolysis and gluconeogenesis do not operate at the same time in the cell. pathway glucose biosynthesis carbohydrate biosynthesis