Which molecule within red blood cells carries respiratory gases?

Which molecule within red blood cells carries respiratory gases?

• A. Hemoglobin
• B. Albumin
• C. Fibrinogen
• D. Keratins

Answer: (A)

Oxygen and carbon dioxide are carried by hemoglobin inside red blood cells. Hemoglobin is a protein with iron-containing heme groups that reversibly bind oxygen in the lungs and release it to tissues. It also binds carbon dioxide as carbaminohemoglobin and, more broadly, facilitates CO2 transport back to the lungs by converting much of it to bicarbonate inside red blood cells via carbonic anhydrase, with the bicarbonate then moving into plasma. This makes hemoglobin the primary molecule within red blood cells responsible for moving respiratory gases. The other listed proteins serve different roles in the blood or tissues and are not the carriers of gases inside red blood cells.

Oxygen and carbon dioxide are carried by hemoglobin inside red blood cells. Hemoglobin is a protein with iron-containing heme groups that reversibly bind oxygen in the lungs and release it to tissues. It also binds carbon dioxide as carbaminohemoglobin and, more broadly, facilitates CO2 transport back to the lungs by converting much of it to bicarbonate inside red blood cells via carbonic anhydrase, with the bicarbonate then moving into plasma. This makes hemoglobin the primary molecule within red blood cells responsible for moving respiratory gases. The other listed proteins serve different roles in the blood or tissues and are not the carriers of gases inside red blood cells.