1) Each iron atom can form 6 coordination bonds: 2 of these bonds are formed b/t iron and oxygen
2) Both hemoglobin and myoglobin contain a prosthetic group called heme, which contains a central iron atom
3) The heme prosthetic group is buried within the protein
4) Molecular oxygen binds reversibly to the Fe(II) atom in heme
5) Hemoglobin is a heterotetramer, whereas myoglobin is a monomer.
6) By itself, heme is not a good oxygen carrier. It must be part of a larger protein to prevent oxidation of the iron
7) Each hemoglobin or myoglobin molecule can bind 4 oxygen molecules