Mr. r has beta-thalassemia minor; he is heterozygous for the beta-thalassemia gene, so he only makes half as many beta chains as normal. the red blood cells containing abnormal hemoglobin are destroyed more rapidly, so mr. r suffers from mild anemia (low hematocrit). what are the beta chains, and why are they important in the hemoglobin molecule?

A healthy normal hemoglobin molecule is formed of four polypeptide chains: two alpha and two beta chains. Therefore, beta chains interact with alpha chains in order to form a functional haemoglobin molecule. Each haemoglobin molecule has four heme groups and each heme group has an iron atom which binds one oxygen molecule. Therefore, beta chains are two of the four proteins which hold heme groups in position and modulate their oxygen-binding properties.