Final answer:
Iron bound to transferrin in the bloodstream is mainly removed by the liver and red bone marrow, where it is either stored in ferritin and hemosiderin or used to produce new red blood cells.
Step-by-step explanation:
Iron is an essential trace mineral critical for the production of hemoglobin in red blood cells. Transferrin is a blood protein that binds iron in the bloodstream and transports it to various tissues, including the liver and spleen where it can be stored, or the red bone marrow for use in erythropoiesis.
Iron transported by transferrin is removed from the bloodstream primarily by the liver and red bone marrow. In the liver, iron may be stored in the form of ferritin or hemosiderin, while in the red bone marrow, it is used for the synthesis of new erythrocytes.
When the body needs iron for functions such as hemoglobin synthesis, iron is released from transferrin by reduction to the more soluble Fe²⁺ form. The released iron can then be utilized immediately or stored in ferritin within cells. Ferritin functions as an iron-storage complex, capable of holding a large number of iron atoms in a safe and bioavailable form. If the body's iron requirements increase, the stored iron is mobilized from ferritin and then transported back into the bloodstream by transferrin to meet the body's needs.