Glycolysis and gluconeogenesis are two opposing metabolic pathways. Glycolysis is the breakdown of glucose to produce ATP, while gluconeogenesis is the synthesis of glucose from non-carbohydrate precursors.In glycolysis, one molecule of glucose 6 carbons is broken down into two molecules of pyruvate 3 carbons each . The net energy yield of glycolysis is 2 ATP molecules and 2 NADH molecules per molecule of glucose. The 2 NADH molecules can be further used in the electron transport chain to produce more ATP approximately 5 ATP per NADH, but this can vary . So, the total ATP yield from glycolysis is approximately 12 ATP molecules 2 from glycolysis + 10 from 2 NADH .Gluconeogenesis, on the other hand, consumes ATP to synthesize glucose from non-carbohydrate precursors. It requires the input of 6 ATP molecules 4 ATP and 2 GTP to produce one molecule of glucose.Since glycolysis and gluconeogenesis are opposing pathways, when considering both pathways together, the net energy yield in ATP molecules for each molecule of glucose metabolized would be zero. This is because the energy gained from breaking down glucose in glycolysis is used to synthesize glucose in gluconeogenesis.