Which cell type is primarily responsible for carrying oxygen?

Which cell type is primarily responsible for carrying oxygen?

• A. Red Blood Cells
• B. White Blood Cells
• C. Platelets
• D. Plasma

Answer: (A)

Oxygen transport in the blood is carried primarily by red blood cells because they contain hemoglobin, a protein that binds oxygen in the lungs where oxygen levels are high and releases it in tissues where it’s needed. Hemoglobin has four heme groups with iron that reversibly bind four oxygen molecules, allowing efficient transport throughout the body. In mammals, mature red blood cells are optimized for this job: they have a biconcave shape to maximize surface area for gas exchange and lack mitochondria, so they don’t use the oxygen they’re carrying. The other components—white blood cells, platelets, and plasma—have different roles (defense, clotting, and the liquid portion of blood, respectively) and do not primarily carry oxygen.

Oxygen transport in the blood is carried primarily by red blood cells because they contain hemoglobin, a protein that binds oxygen in the lungs where oxygen levels are high and releases it in tissues where it’s needed. Hemoglobin has four heme groups with iron that reversibly bind four oxygen molecules, allowing efficient transport throughout the body. In mammals, mature red blood cells are optimized for this job: they have a biconcave shape to maximize surface area for gas exchange and lack mitochondria, so they don’t use the oxygen they’re carrying. The other components—white blood cells, platelets, and plasma—have different roles (defense, clotting, and the liquid portion of blood, respectively) and do not primarily carry oxygen.