The question is, why was that necessary? Well, the reason we transform the glucose into the fructose is so that once this step takes place in stage two, we form two molecules that each have three carbons. Because if that glucose was not transformed into fructose, and it's the fructose one, six bits phosphate, that moved on to stage two, then once this reaction took place, in that case, we would have formed one molecule with two carbons and the other molecule with four carbons. And so to have this symmetry in which the two products have the same number of carbons, that's why in stage one, we have to transform that glucose into its isomer fructose. Now, let's take a look at these two products. Notice that one of these products is that product that we want to form in stage two.