Which cell type is primarily responsible for oxygen transport in the blood?

Which cell type is primarily responsible for oxygen transport in the blood?

• A. Thrombocytes
• B. Erythrocytes
• C. Leukocytes
• D. Plasma proteins

Answer: (B)

Oxygen transport in the blood is carried primarily by red blood cells because they contain hemoglobin, a protein with iron-containing heme groups that reversibly bind oxygen. In the lungs, oxygen binds to hemoglobin to form oxyhemoglobin, enabling most of the oxygen to be carried through the bloodstream. When red blood cells reach tissues where oxygen is needed and the environment has lower oxygen tension, hemoglobin releases the oxygen to support cellular respiration. Platelets are involved in clotting, white blood cells defend against infection, and plasma proteins support roles like maintaining blood volume and transporting various substances—none of these serve as the main oxygen carriers like hemoglobin does in erythrocytes.

Oxygen transport in the blood is carried primarily by red blood cells because they contain hemoglobin, a protein with iron-containing heme groups that reversibly bind oxygen. In the lungs, oxygen binds to hemoglobin to form oxyhemoglobin, enabling most of the oxygen to be carried through the bloodstream. When red blood cells reach tissues where oxygen is needed and the environment has lower oxygen tension, hemoglobin releases the oxygen to support cellular respiration. Platelets are involved in clotting, white blood cells defend against infection, and plasma proteins support roles like maintaining blood volume and transporting various substances—none of these serve as the main oxygen carriers like hemoglobin does in erythrocytes.