Now, for glycolysis to actually continue taking place, the NAD plus molecules that are used up in glycolysis must be regenerated. And that's because NAD plus concentration is limited inside our cells and under aerobic conditions, when we have oxygen present side ourselves, these NAD plus molecules are regenerated on the electron transport chain. So the NADH molecules that we form in glycolysis must somehow move onto the electron transport chain found on the inner membrane of the mitochondria. And there the electrons are extracted from the NADH to form the NAD plus. And electrons are also used to actually generate ATP molecules. So the question that I'd like to focus on in this lecture is how exactly do the NADH molecules produced in the process of glycolysis actually get to the electron transport chain?