And let's begin with glycolysis. So glycolysis takes place entirely in the cytoplasm of the cell. And so let's suppose this is the cytoplasm and this is the mitochondrion. Now, a single glucose is broken down into two Pyruvate molecules in glycolysis. And in the process, we also generate two ATP molecules and we produce two NADH molecules. Now, the ATP molecules can be used directly by the cell to power some type of biological process in that cell.