Question

In many animal cells, the uptake of glucose into the cell occurs by a cotransport mechanism, in which glucose is cotransported with Na⁺ ions.

Complete the diagram below using the following steps.

• Drag the pink labels to the pink targets, indicating the relative concentration at glucose inside and outside the cell.
• Drag the correct white target to the white target, indicating the direction that Na⁺ ions and glucose move through the cotransporter
• Drag the blue labels to complete the sentences on the right, indicating how Na⁺ ions and glucose move through the cotransporter relative to their electrochemical and concentration gradients.

Answer 1

The sodium-glucose-linked transporter (SGLTs, a co-transporter) uses the ATPase pump's energy through the downhill sodium ion gradient for glucose transportation across the apical membrane (against the glucose gradient). SGLTs are an example of secondary active transport. The glucose transporters (GLUT) present in the basolateral membrane now allow the glucose transport into the peritubular capillaries. Inhibition of the Na+/K+/ATPase fails to generate the energy required for the SGLT secondary transporters, inhibiting glucose uptake.

Sugars such as glucose, galactose into the microvilli epithelial cells are based on sodium mediated cotransport, whereas fructose cannot be transported by sodium mediated transport during absorption after digestion. H+ mediated oligopeptide transport is present in the gut epithelium.