Final answer:
Bilirubin does not contain iron. It is a breakdown product of heme from hemoglobin, unlike hemosiderin, transferrin, and ferritin, which are related to iron storage and transport.
Step-by-step explanation:
Among the substances listed, bilirubin does not contain iron. Hemosiderin, transferrin, and ferritin are all related to iron storage and transport. Hemosiderin and ferritin are iron storage proteins, whereas transferrin is a blood plasma protein that binds and transports iron. Bilirubin, however, is a breakdown product of heme from hemoglobin but does not contain iron; it is associated with bile production in the liver.