Complete the sentences about heme. Some terms will not be used. The prosthetic group of hemoglobin and myoglobin is . The organic ring component of heme is ___. Under normal conditions, the central atom of heme is ___. In , the central iron atom is displaced 0.4 Å out of the plane of the porphyrin ring system. The central atom has bonds: to nitrogen atoms in the porphyrin, one to a residue, and one to oxygen.

Heme is the prosthetic group of myoglobin and hemoglobin.  

Porphyrin is the organic ring constituent of heme.  

Fe2+ is the central atom of heme under usual circumstances.  

The central iron atom gets displaced by 0.4 Angstrom out of the plane of the porphyrin ring system in deoxyhemoglobin.  

The central atom comprises of six bonds, that is, four to nitrogen atoms, one to oxygen, and one to a histidine residue in the porphyrin ring.