What makes up a hemoglobin molecule?

A hemoglobin molecule consists of four polypeptide chains, known as globins, folded into a specific quaternary structure. These globin chains are named alpha, beta, gamma, and delta, depending on their amino acid sequences and structural characteristics. Each globin chain contains a heme group, which is an iron-containing porphyrin ring. These heme groups are responsible for binding oxygen molecules.

The four globin chains come together to form the quaternary structure of hemoglobin. The arrangement of these chains is essential for cooperative oxygen binding and release. The specific interactions between the globin chains and the heme groups allow hemoglobin to bind and release oxygen at appropriate pressures of oxygen in the tissues and lungs, facilitating efficient oxygen transport.