Now, that's not really a problem when the hemoglobin is bound to oxygen. But as soon as the hemoglobin unloads that oxygen in the tissues, what happens is the three dimensional shape of that hemoglobin changes as a result of that valine amino acid. And so what happens is because the red blood cells are filled with these hemoglobin molecules. And because these hemoglobin proteins change their shape, the entire red blood cell also changes its shape. It changes its shape from a biconcave shape to a sickle half moon shape. Now, because of the shape, these red blood cells, the sickle red blood cells, can actually aggregate together and they can form clogs, clots inside the veins of our body because it's inside the veins that our red blood cells have unloaded that oxygen.