The diagram below shows how glucose and other nutrients are transported from the inside of the intestine (intestinal lumen), through an intestinal epithelial cell, into the extracellular fluid for delivery to the bloodstream. There are different proteins on either side of the epithelial cell as shown in the diagram. The color of the proteins is consistent within any given type of membrane transport.
a) Fill in the inferred relative concentrations of Na + ions and amino acids with High or Low on the lines below. Use the information provided for glucose to help you infer solute concentrations.
b) For each of the three letters (A, B and C) associated with the thick arrows, please describe the type of protein depicted, the type of transport it engages in and be specific about the source of energy used.