Oxygen binding refers to the process by which hemoglobin, a protein found in red blood cells, attaches to oxygen molecules in the lungs. This binding occurs when oxygen enters the bloodstream, allowing hemoglobin to pick up oxygen and transport it to various tissues throughout the body. Once the oxygen reaches the tissues, hemoglobin releases it, enabling cells to use oxygen for energy production. The ability of hemoglobin to bind and release oxygen efficiently is crucial for maintaining proper cellular function and overall health.