The first three reactions in glycolysis are often referred to as the "investment phase, " since energy must be utilized by breaking down two molecules of ATP. The net of the first 3 reactions in glycolysis is shown in reaction (5) below. (5) Glucose + 2 ATP rightarrow Fructose 1, 6-bisphosphate + 2 ADP The later reactions of glycolysis are the "payoff" phase, since the initial energy invested and more is recovered in the formation of high-energy molecules. The net of the payoff phase is shown in reaction (6) below. (6) Fructose 1, 6-bisphosphate + 4 ADP + 2 Pi + 2 NAD^+ rightarrow 2 Pyruvate + 4 ATP + 2 NADH What is the net reaction for glycolysis? Glucose + Fructose 1, 6-bisphosphate + 2 ADP + 2 NAD^+ rightarrow 2 Pyruvate + 2 ATP + 2 NADH Glucose + Fructose 1, 6-bisphosphate + 2 ADP + 2P_i rightarrow 2 Pyruvate+ 2 ATP + 2 NADH Glucose + 2 ADP + 2 P_i + 2 NAD^+ rightarrow 2 Pyruvate + 2 ATP + 2 NADH Glucose + 2 ADP + 2 NAD^+ rightarrow 2 Pyruvate + 4 ATP + 2 NADH