Final answer:
Transferrin binds to the receptor CD71 on the apical surface of enterocytes, allowing for iron absorption.
Step-by-step explanation:
The receptor CD71 on the apical surface of enterocytes binds to transferrin. Transferrin is a protein responsible for transporting iron in the body. It binds to CD71, allowing iron to enter the enterocyte and be transported across the apical surface. This mechanism helps regulate iron absorption in the intestines.