How many heme groups does a single hemoglobin molecule contain?

A single hemoglobin molecule contains four heme groups. Each heme group is an iron-containing compound that serves as the site for oxygen binding. This structure is crucial for the molecule's function in transporting oxygen throughout the body. Hemoglobin consists of four polypeptide chains that come together to form a tetrahedral structure, with each chain associated with one heme group. The presence of four heme groups allows hemoglobin to bind to four molecules of oxygen, optimizing its efficiency in oxygen transport. Understanding this is essential for grasping how oxygen delivery works in the human body, making the structure of hemoglobin and its heme groups a fundamental concept in medical technology and related fields.