Compare the atp yield of three glucose molecules that enter glycolysis and are converted to pyruvate with that of three glucose molecules that proceed through the pentose phosphate pathway such that their carbon skeletons (as two f6p and one gap) reenter glycolysis and are metabolized to pyruvate

In glycolysis, for every glucose molecule, two pyruvate are produced as an end product and a net of 2 ATPs. Therefore, the net yield of 3 glucose molecules is 6 ATPs. The pentose phosphate pathway has no ATP yield since it is mainly an anabolic process, that requires energy, unlike glycolysis which is catabolic.