This molecule here is this mitochondrial glycerol three phosphate dehydrogenase that we discussed in this diagram. And so, ultimately, the two electrons are passed onto this molecule and then the Ubiquinol takes those two electrons and becomes Ubiquinol and passes those two electrons directly onto complex three. And what that means is we essentially bypass complex one because when the NADH molecules are produced in a citric acid cycle, because the citric acid cycle takes place in the matrix of the mitochondria, these NADH molecules actually pass down their electrons onto complex one of the electron transport chain. 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.