What is the function of hemoglobin in red blood cells?

Hemoglobin is a specialized protein found in red blood cells whose primary function is to transport oxygen from the lungs to tissues throughout the body. When we inhale, oxygen enters the lungs and diffuses into the bloodstream where it binds to hemoglobin. Each hemoglobin molecule can carry up to four oxygen molecules, which is crucial for meeting the oxygen demands of body tissues during cellular respiration.

Once hemoglobin is in the circulatory system, it releases the oxygen in areas where it’s needed, especially in actively metabolizing tissues. This ability to both bind and release oxygen efficiently makes hemoglobin essential for maintaining aerobic respiration, which is vital for energy production in cells.

While hemoglobin does play a role in the transport of carbon dioxide back to the lungs (though this is primarily carried in the form of bicarbonate ions in the plasma), its primary and most critical function is the transport of oxygen. Nutrient absorption and waste removal are functions carried out by other systems and organs in the body, such as the digestive system and kidneys respectively.