Describe why hemoglobin is dependent upon iron and its heme groups to transport oxygen throughout ...

Iron is a component of many proteins in the body, including various enzymes and hemoglobin, which is the oxygen-carrying protein found in red blood cells. Almost two-thirds of all of the iron in the body is found in hemoglobin. The hemoglobin molecule consists of four polypeptide chains studded with four iron-containing heme groups. The body cannot survive more than a few minutes without oxygen. Thus, hemoglobin's ability to transport oxygen throughout the body is absolutely critical to life. To carry oxygen, hemoglobin depends on the iron in its heme groups. Iron is able to bind with and release atoms such as oxygen, nitrogen, and sulphur very easily. It does this by transferring electrons to and from the other atoms as it moves between various oxidation states. In the bloodstream, iron acts as a shuttle, picking up oxygen from the environment, binding it during its transport in the bloodstream, and then dropping it off again in the tissues.