This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Metabolism of protein and amino acid, Subject name: Biochemistry
Albumin serves as a transpoer of all the following molecules, Except 
Select and explain. 
A. Bilirubin, B. Free fatty acids, C. Thyroxine, D. Iron
D: Iron
Answer: D: Iron 
Explanation: One of the major roles of albumin is to bind to and thereby facilitate the transpo of numerous ligands. These include free fatty acids (FFA), calcium, ceain steroid hormones, bilirubin, copper, and some of the plasma tryptophan. A variety of drugs, including sulfonamides, penicillin G, dicumarol, and aspirin, are bound to albuminHarper 30th edition pg: 671