During glycolysis glucose is converted to fructose through rearrangement of its atoms. To this fructose are added two phosphate molecules which becomes fructose-1,6 biphosphate because the phosphate molecules are attached at carbon 1 and 6 of the fructose.
This phosphorylated fructose molecule is then split into two 3-carbon molecules to form a couple of glucose- 3- phosphate (G3P) molecules, each of which gains another phosphate molecule.
Finally these two G3P molecules transfer their phosphate molecules to electron carriers and they each becomes a pyruvate.
So the glucose molecule is split into two pyruvate molecules.