But to produce ATP molecules from NADH, the NADH must move onto the electron transfer chain found on the inner membrane of the mitochondrion. So we have the outer membrane, the inner membrane, we have electron transport chain, and this is the matrix of the mitochondria and this is the intermembrane space. Now the question is how many ATP molecules do we actually form when a single NADH is transported onto the electron transport chain from the cytoplasm? Well, the answer to that question basically depends on the type of shuttle that the cell actually uses. Some cells, such as skeleton muscle cells, use a shuttle known as the glycerol threephosphate shuttle. And in this particular case, the high energy electrons are transported onto complex three of the electron transport chain.