Final answer:
Without the enzyme enolase, glycolysis is incomplete, leading to a net zero ATP production from glycolysis because the final steps of ATP generation would not occur.
Step-by-step explanation:
In the absence of enolase, glycolysis cannot be completed because enolase is required for the conversion of 2-phosphoglycerate to phosphoenolpyruvate in one of the later steps of glycolysis. Under normal circumstances, the entire glycolytic pathway, which converts glucose to pyruvate, yields a net gain of two ATP molecules per molecule of glucose.
However, if enolase is lacking and glycolysis is incomplete, the last steps that yield ATP cannot occur. Without the completion of these steps, the net ATP production from glycolysis would effectively be zero because cells would only go through the ATP-consuming phase without reaching the ATP-producing phase. It is important to highlight that glycolysis, when fully operational, also produces two NADH molecules per glucose molecule, which can subsequently be used in the electron transport chain under aerobic conditions.