Glycolysis and gluconeogenesis are two metabolic pathways that play crucial roles in glucose metabolism. Glycolysis is the process of breaking down glucose into two molecules of pyruvate, while gluconeogenesis is the process of synthesizing glucose from non-carbohydrate precursors. Both processes involve the production and consumption of ATP, and their net ATP gain can be calculated by considering the ATP molecules produced and consumed in each step.Glycolysis:Glycolysis is a ten-step process that occurs in the cytoplasm of the cell. It can be divided into two phases: the energy investment phase and the energy payoff phase.1. Energy investment phase Steps 1-5 : In this phase, two ATP molecules are consumed per glucose molecule. The net ATP gain in this phase is -2 ATP.2. Energy payoff phase Steps 6-10 : In this phase, four ATP molecules are produced per glucose molecule, and two NADH molecules are generated. The net ATP gain in this phase is +4 ATP.Considering both phases, the net ATP gain in glycolysis is +2 ATP per glucose molecule.Gluconeogenesis:Gluconeogenesis is a process that occurs mainly in the liver and, to a lesser extent, in the kidneys. It consists of 11 steps, with seven steps being the reverse of glycolysis and four steps being unique to gluconeogenesis. The four unique steps consume ATP or GTP, which are high-energy molecules.1. Conversion of pyruvate to phosphoenolpyruvate PEP : This step involves two reactions and consumes 2 ATP molecules and 1 GTP molecule per glucose molecule. The net ATP consumption in this step is -3 ATP.2. Conversion of fructose-1,6-bisphosphate to fructose-6-phosphate: This step consumes 1 ATP molecule per glucose molecule. The net ATP consumption in this step is -1 ATP.3. Conversion of glucose-6-phosphate to glucose: This step does not involve ATP consumption or production.Considering the unique steps in gluconeogenesis, the net ATP consumption is -4 ATP per glucose molecule.Net ATP gain in glycolysis and gluconeogenesis:Since glycolysis has a net ATP gain of +2 ATP and gluconeogenesis has a net ATP consumption of -4 ATP, the overall net ATP gain in the combined process of glycolysis and gluconeogenesis is -2 ATP per glucose molecule.It is important to note that the net ATP gain can be affected by factors such as the efficiency of the electron transport chain, the availability of substrates, and the presence of regulatory enzymes. Additionally, the NADH produced in glycolysis can generate more ATP through oxidative phosphorylation, which can further influence the net ATP gain.