Question

Write a narrative that would accompany this figure. Make sure that you provide an

explanation for as many of the steps as possible. Be sure to describe the forces that are
acting to allow molecules to move across the membrane, why the forces are required, etc.

Answer 1

The narrative that would accompany this figure is: Glucose, present in the intestinal lumen, enters intestinal epithelial cells through the apical membrane by binding to the glucose transporter GLUT2. GLUT2, a symporter, facilitates the co-transport of glucose and sodium ions (Na+) into the cell along their respective concentration gradients.

This process is powered by the sodium-potassium (Na+/K+) pump, which utilizes energy from ATP to maintain the Na+ gradient. Once inside the cell, glucose dissociates from GLUT2 and diffuses across the basolateral membrane into the bloodstream. This mechanism ensures the efficient absorption of glucose from the diet into the body.

So, The diagram shows the transport of glucose across the intestinal epithelium, from the intestinal lumen to the bloodstream. The process is mediated by a glucose transporter protein, GLUT2, which is located in the apical membrane of the intestinal epithelial cells.