How Mammals Acquire and Distribute Iron Needed for Oxygen-Based Metabolism

V irtually all cells and organisms require iron to perform basic cellular processes. In respiration, iron proteins capture energy released from oxidation of food by synthesizing high-energy compounds, such as NADH, that are used to fuel cellular metabolism. Iron also enables hemoglobin in red blood cells to bind and transport oxygen to tissues throughout the body. Since iron is indispensable for respiration and oxygen transport, it is not surprising that cellular acquisition of iron has not been left to chance. It can be a challenge for organisms to obtain sufficient iron because much environmental iron is very insoluble. Thus, elaborate systems for uptake of