Now, slight changes to the coronary structure of our hemoglobin can actually increase or decrease definitive of the hemoglobin molecule to oxygen as we'll see when we discuss the hemoglobin molecule in much more detail. So we see that there are four levels of structure in protein. So we have primary structure which is a sequence of our amino acids. We have the secondary structure which are basically these regular patterns that are formed so alpha, helixes, beta sheets, beta turns and omega loops. We have our tertiary structure which basically consists of these amino acids that are far away from one another and they interact with one another to give that tertiary structure. And finally, we also have those proteins that contain a fourth level quadinary structure.