The carbonic anhydrase reactions are important for regulating pH because the bicarbonate ion acts as a buffer. What are three cells, one each in the respiratory, digestive, and urinary systems, where the carbonic anhydrase reaction has been described, producing bicarbonate ion that can help to buffer the pH of blood?
How are absorption in the digestive tract and reabsorption from the renal tubules similar? (Your answer should concentrate on the molecular level.)