Final answer:
The correct answer is carbonic anhydrase, an enzyme in red blood cells responsible for converting carbonic acid into bicarbonate ions and hydrogen ions.
Step-by-step explanation:
The Enzyme in Red Blood Cells
The enzyme found in red blood cells that catalyzes the reversible conversion of carbonic acid (H2CO3) into bicarbonate ions (HCO3−) and hydrogen ions (H+) is known as carbonic anhydrase (CA). This same enzyme is involved in various physiological processes, such as the transportation of CO2 within red blood cells, assisting in the production of hydrochloric acid in the stomach, and helping in the production of bicarbonate ions to buffer acidic chyme in the pancreas. In the kidney, carbonic anhydrase facilitates the conversion of bicarbonate into carbon dioxide (CO2) and water (H2O), which then diffuses back into the cell, where it is reversed to regenerate bicarbonate ions. This reaction, in which carbon dioxide and water react to form bicarbonate and hydrogen ions within red blood cells, is pivotal for the transportation of CO2 from tissues to the lungs and is central to the bicarbonate buffer system.
Therefore, the correct answer to the student's question is: 1) Carbonic anhydrase.