Final answer:
In the absorption process in the ileum, vitamin B12 is detached from the Intrinsic Factor (IF) and then binds to transcobalamin II, which transports the vitamin through the bloodstream.
Step-by-step explanation:
The student's question pertains to the absorption and transport mechanism of vitamin B12 in the human body, specifically in the ileum which is the final part of the small intestine. After the vitamin B12-Intrinsic Factor (IF) complex dissociates in the ileum, vitamin B12 is then bound to transcobalamin II, which is the carrier protein responsible for transporting vitamin B12 through the bloodstream to various parts of the body where it is needed. This absorption process is highly specialized because vitamin B12 is a large molecule that requires the intrinsic factor for transportation, unlike other water-soluble vitamins that are absorbed by simple diffusion.