Final answer:
Glucose uses the sodium-glucose symporter (SGLT) to cross the apical border of cells by secondary active transport, coupling the inward movement of glucose with the movement of sodium ions down their gradient.
Step-by-step explanation:
The transporter that glucose uses to cross the apical border is known as the sodium-glucose symporter or SGLT. This symporter utilizes the mechanism of secondary active transport, which means it moves glucose into cells against its concentration gradient by coupling the movement with the movement of sodium ions down their electrochemical gradient. This gradient is maintained by the sodium-potassium ATPase, which pumps sodium out of the cells, allowing glucose to move into the cells via the SGLT on the apical surface and then exit into the interstitial space by facilitated diffusion.