Question

Identify the correct statement with respect to the transport of respiratory gases by blood.

• A. Haemoglobin is necessary for the transport of oxygen and carbonic anhydrase for the transport of carbon dioxide.
• B. Only oxygen is transported by blood.
• C. Haemoglobin is necessary for the transport of carbon dioxide and carbonic anhydrase for the transport of oxygen.
• D. Only carbon dioxide is transported by blood

Answer 1

The correct option is A

Haemoglobin is necessary for the transport of oxygen and carbonic anhydrase for the transport of carbon dioxide.

Oxygen diffuses from the plasma into the red blood cells where it joins with the $F{e}^{2+}$ ions of haemoglobin to form oxyhaemoglobin and thus transports oxygen.

About $60\%$ of carbon dioxide released by the tissue cells diffuses into the plasma and then into the red blood cells. Carbon dioxide combines with water to form carbonic acid. This reaction is catalysed by the enzyme carbonic anhydrase.