Question

Glucose moves into the intestinal epithelium by...

a. attaching itself to two Na+ ions
b. passive facilitated diffusion
c. secondary active transport
d. passing through an active antiport protein
e. simple diffusion through the phospholigipid bilayer

Answer 1

Glucose is absorbed into the intestinal epithelium by secondary active transport, utilizing a Na+/glucose symporter and the energy from the sodium ion gradient maintained by the Na+/K+ ATPase.

Step-by-step explanation:

Glucose moves into the intestinal epithelium by secondary active transport. This process involves a symporter protein that binds glucose together with two Na+ ions. The Na+/glucose symport protein moves both glucose and Na+ into the cell as Na+ moves down its electrochemical gradient which is maintained by the Na+/K+ ATPase on the basal membrane. This symport mechanism allows glucose to be transported against its concentration gradient into the cell, utilizing the energy from the sodium ion gradient. Once inside, glucose diffuses into the blood through facilitated diffusion.