Final answer:
Increased glucose concentration on the serosal side of an everted gut preparation indicates active glucose transport is occurring, powered by the Na+/K+ ATPase which drives secondary active transport of glucose concomitant with Na+ movement according to its electrochemical gradient.
Step-by-step explanation:
The finding from an everted gut preparation that would support the idea that active glucose transport is driven by a Na+/K+ ATPase on the serosal side is increased glucose concentration on the serosal side. When the glucose concentration is higher on the serosal side while lower on the mucosal side, it suggests that glucose is being actively transported across the epithelium. This movement of glucose against its concentration gradient indicates the presence of an active transport mechanism, likely powered by the Na+/K+ ATPase, which uses ATP to pump sodium out and potassium into the cell. This results in a concentration gradient that drives the co-transport of glucose and sodium into the cell from the mucosal side, a process known as secondary active transport.
The Na+/K+ ATPase actively pumps Na+ out of the cell on the basal surface, thereby maintaining a low concentration of Na+ inside the cell and high concentration in the interstitial space, which favors the movement of Na+ from the tubular lumen into the cell via a symport protein that also carries glucose. The glucose then leaves the cell and enters the interstitial space by facilitated diffusion, with the entire process relying on the energy provided by the Na+/K+ ATPase.