Final answer:
Carbon dioxide is transported in blood by three different mechanisms: as dissolved carbon dioxide, as bicarbonate, or as carbaminohemoglobin. The largest amount of transported carbon dioxide is bicarbonate, formed in erythrocytes. The correct option is A) Carbamino compounds, dissolved in plasma, bicarbonate ions
Step-by-step explanation:
Carbon dioxide is transported in blood by three different mechanisms: as dissolved carbon dioxide, as bicarbonate, or as carbaminohemoglobin. The largest amount of transported carbon dioxide is bicarbonate, formed in erythrocytes.
Carbon dioxide combines with water to form carbonic acid, which dissociates into bicarbonate and hydrogen ions. Bicarbonate is moved across the erythrocyte membrane into the plasma in exchange for chloride ions.
At the pulmonary capillaries, bicarbonate re-enters erythrocytes and is converted back into carbon dioxide and water.
An intermediate amount of carbon dioxide binds directly to hemoglobin to form carbaminohemoglobin. The less saturated the hemoglobin is, the more readily it binds to carbon dioxide. This is known as the Haldane effect.
A small portion of carbon dioxide remains dissolved directly in the blood. The correct option is A) Carbamino compounds, dissolved in plasma, bicarbonate ions