Energy requiring phase:

1. Glucose is phosphorylated at C6 by ATP through hexokinase forming glucose-6-phosphate.
2. Glucose-6-phosphate is then converted to its isomer fructose-6-phosphate via phosphoglucoisomerase
3.  Fructose-6-phosphate is phosphorylated again at C1 by ATP through phosphofructokinase to form fructose 1,6-bisphosphate
4. Fructose 1,6-bisphosphate cleaves into dihydroxyacetone phosphate (DHAP) and D-glyceraldehyde-3-phosphate (G3P); only G3P continues through the following steps of glycolysis
5.  DHAP is converted into G3P by the enzyme triose phosphate isomerase to continue the steps of glycolysis (all of the DHAP is converted)