Select all statements that correctly describe hemoglobin and myoglobin structure. Both hemoglobin and myoglobin contain a prosthetic group called heme, which contains a central iron (Fe) atom. Each hemoglobin molecule can bind four oxygen molecules; each myoglobin can bind one oxygen molecule. Molecular oxygen binds irreversibly to the Fe(II) atom in heme. The heme prosthetic group is entirely buried within myoglobin. Hemoglobin and myoglobin are heterotetramers. Each iron atom can form six coordination bonds. One of these bonds is formed between iron and oxygen. By itself, heme is not a good oxygen carrier. It must be part of a larger protein to prevent oxidation of the iron..