2
If 2 NADH molecules were produced in glycolysis, it means that 1 glucose molecule was broken down. Each glucose molecule yields 2 NADH molecules during glycolysis.
Glycolysis is the breakdown of glucose by enzymatic action. It yields 2 NADH molecules and 2 ATP molecules per glucose molecule.
Glycolysis produces a net of 2 ATP molecules per glucose molecule.
The metabolic end product of aerobic glycolysis is pyruvate. From one molecule of glucose, two molecules of pyruvate are produced through the process of glycolysis.
Four
The first three-carbon compound produced in glycolysis is glyceraldehyde-3-phosphate (G3P) from the six-carbon glucose molecule. This occurs after the glucose molecule is broken down into two molecules of pyruvate.
4 molecules of ATP are produced per molecule of glucose in glycolysis, but 2 are needed (used, degraded, etc.) to start the reaction, so there is really only a net gain of 2 ATP in the process of glycolysis.
Approximately 30-32 molecules of ATP are produced by oxidative phosphorylation for each glucose molecule that enters glycolysis.
In anaerobic respiration one glucose molecule produces a net gain of two ATP molecules (four ATP molecules are produced during glycolysis but two are required by enzymes used during the process). In aerobic respiration a molecule of glucose is much more profitable in that a net worth of 34 ATP molecules are generated (32 gross with two being required in the process).
During glycolysis, ATP is both consumed and produced. Two molecules of ATP are consumed in the initial steps of glycolysis to activate the glucose molecule. However, four molecules of ATP are then produced during the later steps, resulting in a net gain of two ATP molecules per glucose molecule metabolized.
34 ATP molecules are produced by the end of the electron transport chain.
In anaerobic respiration, 2 ATP molecules are produced per glucose molecule through glycolysis.