So, since the mitochondrial membrane is a permeable to NADH molecules, the solution is to extract electrons from NADH produced in a glycolytic pathway and ultimately pass them down to Ubiquinol to form Ubiquinone and then Ubiquinone. Ubiquinol essentially completely bypasses complex one because it gives the two electrons onto complex three. And since NADH from glycolysis bypasses complex one, it only produces a net result of 1.5 ATP molecules rather than the 2.5 which are produced from the NADH that is formed in the citric acid cycle that takes place in the matrix of the mitochondria. Now, this process, called a glycerol three phosphate shuttle, is used predominantly by skeleton muscle cells. And this process allows the skeleton muscle cells not only to use the high energy electrons to generate the much needed ATP molecules, but it also allows the skeleton muscle cells to actually regenerate the entity plus molecules needed to continue glycolysis. Now, this actually is not the only type of shuttle that our cells can use.