A hemoglobin molecule is composed of how many heme molecules and globin chains?

A hemoglobin molecule is made up of four heme molecules and four globin chains. Each hemoglobin molecule consists of a tetrameric structure, meaning it has four subunits. These subunits include two alpha and two beta globin chains, and each of these globin chains is associated with one heme group. This structure is crucial for its function in oxygen transport, as each heme group can bind one molecule of oxygen because of the iron present in its core.

Understanding this composition helps clarify hemoglobin's role in the body, as it allows for the efficient transportation of oxygen from the lungs to tissues and the return of carbon dioxide from tissues back to the lungs.