Question

Iron is taken up from the gut lumen into enterocytes through which transporter?

• A. DMT1
• B. DMT2
• C. Ferroportin 1
• D. GLUT1

Hint:

Apical entry uses a divalent metal transporter; the basolateral exporter is the trap.

Answer 1

The Correct Option is A

Step 1: Dietary iron in the ferrous form is moved from the intestinal lumen into the enterocyte across the apical (brush-border) membrane by an active transport carrier.

Step 2: That carrier is DMT1 (Divalent Metal Transporter 1), expressed on the apical surface of enterocytes in the upper duodenum. So the answer is DMT1.

Step 3: DMT1 is not iron-specific; it can also transport zinc, copper, cobalt and manganese.

Step 4: The distractors are wrong: there is no important "DMT2" iron transporter, ferroportin 1 exports iron out of the cell at the basolateral membrane (it does not take iron in), and GLUT1 carries glucose, not iron.