Final answer:
The correct option is All of the answers). Carbonic anhydrase is an enzyme found in red blood cells that helps convert carbon dioxide to bicarbonate in the blood, and reversely in the lungs, aiding in CO2 transport and maintaining the blood's acid-base balance.
Step-by-step explanation:
Carbonic anhydrase (CA) is an enzyme within red blood cells (RBCs) essential for the bicarbonate buffering system, which is crucial for maintaining acid-base balance in the blood. CO2 diffuses into RBCs where CA catalyzes its conversion to carbonic acid (H2CO3). This acid spontaneously dissociates into bicarbonate (HCO3−) and hydrogen ions (H+), which leads to a decrease in pH. However, H+ binds to hemoglobin, mitigating pH changes, and HCO3− is exchanged for Cl− ions in a process known as the chloride shift. Ultimately, in the lungs, CA helps to reconvert bicarbonate and H+ back to CO2 and H2O, increasing the availability of CO2 to be expelled during exhalation. Therefore, CA plays a role in both increasing and decreasing the amount of bicarbonate ion in plasma as part of CO2 transport and pH regulation.