But the NADH molecules produced in the cytoplasm via glycolysis, they actually pass down their electrons onto complex three via this enzyme known as glycerol three phosphate dehydrogenase. So because of that, what actually happens is the net number of ATP molecules produced by the NADH, which is formed glycolysis, is only 1.5 compared to a value of 2.5 that is produced by NADH molecules formed in the citric acid cycle. And to see what we mean, let's take a look at the following calculations. So, let's get a red marker and a black marker. Okay, so for those NADH molecules produced in the matrix of the mitochondria V, the citric acid cycle, these NADH molecules are oxidized back into NAD plus along complex one of the electron transport chain. And when these two electrons travel through complex one and ultimately end up on Ubiquinone, a net result of four protons are pumped into the intermembrane space of the mitochondria.