Movement of glucose from one side to the other side of the intestinal epithelium is a major example of transcellular transport. How does the Na⁺/K⁺ ATPase power the process? Why are tight junctions essential for the process? Why is localization of the transporters specifically in the apical and basolateral membrane crucial for transcellular transport? Rehydration supplements such as sport drinks include a sugar and a salt. Why are both important to rehydration?