They can carry a lot of these, many of these oxygen molecules. Now, another important point that I should make is because red blood cells don't actually have any mitochondria, that implies they don't actually use cellular respiration. So that means they do not use up the oxygen supply that is found within our cell. And this is another byproduct of the fact that they do not have any organelle. They are extremely specialized to carry out one purpose, and that is to actually carry those oxygen molecules from one cell to a different cell in our body. Now, let's move on to leukocytes.