And in this particular case, the pyruvate molecules travel into the mitochondria and there they're broken down into acetylcoenzyme A. And that molecule goes into the citric acid cycle and that uses the electron transport chain to basically regenerate those NAD plus molecules. But we'll focus on that process in a future lecture. In this lecture, I'd like to focus on the anaerobic process. The anaerobic process takes place in the absence of oxygen. And our own cells and many other cells in nature use this specific type of process that we call fermentation.