Glucose is transpoed in the presence Na+ ions in intestine. This is a type of
**Core Concept**
The process being tested involves the cotransport of glucose with sodium ions (Na+) in the intestine, which is a type of secondary active transport. This process utilizes the electrochemical gradient of sodium ions to drive the uptake of glucose against its concentration gradient.
**Why the Correct Answer is Right**
Glucose and sodium ions are cotransported through the sodium-glucose cotransporter 1 (SGLT1) in the intestinal epithelial cells. The sodium gradient is maintained by the sodium-potassium pump (Na+/K+-ATPase), which pumps sodium ions out of the cell and potassium ions into the cell against their concentration gradients. The energy from the sodium gradient is used to drive the uptake of glucose against its concentration gradient. This process is an example of secondary active transport, where the energy from an electrochemical gradient of one ion is used to drive the transport of another ion or molecule.
**Why Each Wrong Option is Incorrect**
**Option B:** Primary active transport involves the direct use of ATP to drive the transport of a molecule or ion against its concentration gradient. This is not the case in the transport of glucose in the intestine.
**Option C:** Facilitated diffusion involves the movement of molecules or ions down their concentration gradient without the use of energy. This is not the case in the transport of glucose in the intestine, where glucose is transported against its concentration gradient.
**Option D:** Simple diffusion involves the movement of molecules or ions down their concentration gradient without the use of energy or transport proteins. This is not the case in the transport of glucose in the intestine, where glucose is transported against its concentration gradient.
**Clinical Pearl / High-Yield Fact**
It's essential to remember that the sodium-glucose cotransporter 1 (SGLT1) is responsible for the uptake of glucose in the small intestine, and its dysfunction can lead to glucose malabsorption and diarrhea.
**✓ Correct Answer: A. Secondary Active transport**