What is the function of hemoglobin in red blood cells?

Hemoglobin plays a crucial role in the function of red blood cells by facilitating the transport of oxygen from the lungs to the tissues throughout the body and assisting in the return transport of carbon dioxide from the tissues back to the lungs for exhalation. The structure of hemoglobin allows it to bind to oxygen molecules efficiently; each hemoglobin molecule can carry up to four oxygen molecules, making it a highly effective means for oxygen delivery. When red blood cells pass through the capillaries in the lungs, hemoglobin binds to the oxygen present in the alveoli. As the red blood cells circulate to body tissues, hemoglobin releases this oxygen where it is needed for cellular respiration. Additionally, hemoglobin also binds to carbon dioxide, a waste product of metabolism, during its return journey, thus playing a dual role in gas exchange. This function is critical for maintaining the body's overall oxygen supply and ensuring that carbon dioxide is removed efficiently, vital for homeostasis and metabolic processes.