Final answer:
Plants use the enzyme carbonic anhydrase to convert bicarbonate into carbon dioxide. This enzyme contains a Zn2+ ion that increases the reactivity of water molecules, facilitating the conversion of CO2 to bicarbonate in the blood and the reverse process in the lungs.
Step-by-step explanation:
Plants convert bicarbonate to carbon dioxide using the enzyme carbonic anhydrase. This enzyme is crucial for maintaining acid-base balance in the blood by facilitating the rapid conversion of carbon dioxide and water into carbonic acid, which then dissociates into bicarbonate and hydrogen ions. The reaction catalyzed by carbonic anhydrase is reversible, allowing carbon dioxide to be regenerated from bicarbonate in the lungs and exhaled. This process is vital for transporting carbon dioxide in the blood, where approximately 70 percent of CO2 is converted to bicarbonate for transport.
Carbonic anhydrase contains a Zn2+ ion that acts as a Lewis acid, increasing the reactivity of water molecules bound to it and thus the overall reaction rate. This enzyme operates efficiently within the pH range of most biological tissues (pH 7-8), allowing it to fulfill its role in red blood cells, as well as other tissues like the stomach and pancreas. In the kidney, carbonic anhydrase facilitates the conversion of bicarbonate and hydrogen ions to carbonic acid, then into CO2 and water to maintain the acid-base balance.