Explain the chemical logic of converting glucose to fructose before aldolase splits the sugar in two.

Cellular respiration is the mechanism by which metabolic processes receive energy in the form of ATP from nutrients.

The glucose-6-phosphate generated can be shuttled to other metabolic routes, such as the pentose phosphate pathway, therefore the first step of glycolysis is not the committed phase. Phosphofructokinase-1 converts fructose-6-phosphate to fructose-1,6-bisphosphate, which is the only committed step in glycolysis. Glucose-6-phosphate must first be converted to fructose-6-phosphate in this stage.

Two phosphate groups are linked to fructose-1,6-bisphosphate: one at C-1 and the other at C-6. C-1 is an aldehyde group that cannot be phosphorylated in the structure of glucose; it is first transformed to an alcoholic group by molecular interconversion with C-2, which is then converted to a ketone. Because the ∆G° value for this reaction is so tiny, it happens quickly in the opposite direction. Fructose-1,6 bisphosphate is generated because both C1 and C6 have hydroxyl groups that can be phosphorylated.

The aforementioned glucose to fructose-1,6-biphosphate conversion occurs so that the enzyme aldolase may break the carbon-carbon bond and produce two sugars. Fructose receptors are unique to the aldolase enzyme.