So I can move my arm because of skeleton muscles or I can sprint across the room because of these skeletal muscle cells. Now, skeleton muscle cells have the option of using aerobic or anaerobic respiration. So if there is oxygen present, it will use aerobic, but if not, it will use anaerobic. But red blood cells don't have organelles, they don't have any mitochondria. And what that means is they don't have the cell machinery needed for aerobic respiration. So red blood cells only use anaerobic cellular respiration to produce ATP molecules.