What is the primary role of hemoglobin in gas exchange?

• A. It helps maintain blood pH levels
• B. It binds with carbon dioxide for transport
• C. It carries oxygen from the lungs to tissues
• D. It prevents oxygen loss from tissues

Answer: (C)

The primary role of hemoglobin in gas exchange is to carry oxygen from the lungs to tissues. Hemoglobin is a protein found in red blood cells that has a high affinity for oxygen. When we inhale, oxygen diffuses into the blood in the lungs and binds to hemoglobin, forming oxyhemoglobin. This complex travels through the bloodstream and releases oxygen in the tissues, where it is needed for cellular respiration and energy production.

While hemoglobin does interact with carbon dioxide, its main function is not to bind with it for transport; instead, carbon dioxide is primarily transported in the blood as bicarbonate ions or dissolved in plasma. Although maintaining blood pH levels is an important physiological function, it is not the primary role of hemoglobin. Additionally, hemoglobin does not actively prevent oxygen loss from tissues; rather, it releases oxygen as needed based on factors such as the tissue's metabolic activity. Thus, the central function of hemoglobin regarding gas exchange is its crucial role in oxygen transport from the lungs to the tissues.