Iron

Iron is an essential chemical element used in hemoglobin, myoglobin, and many enzymes. Its ability to switch between oxidation states supports oxygen transport and cellular metabolism.

Heme: A ring-shaped molecule containing an iron atom that binds oxygen or participates in electron transfer. Hemoglobin and myoglobin use heme iron to bind oxygen reversibly.
Ferrous iron: Iron in the +2 oxidation state, often written Fe²⁺. Ferrous iron is the form transported into intestinal cells and used in many reactions.
Iron deficiency: A state in which body iron stores are insufficient to meet physiological needs. Low iron limits hemoglobin production and can impair oxygen delivery.
Erythropoiesis: The production of red blood cells from hematopoietic stem and progenitor cells. Developing red blood cells require iron to make hemoglobin.
Hemoglobin: A red blood cell protein that transports oxygen from the lungs to tissues. Its heme groups bind oxygen through iron atoms.
Ferric iron: Iron in the +3 oxidation state, often written Fe³⁺. Ferric iron is common in storage proteins and must often be reduced before absorption.
Iron-deficiency anemia: Anemia caused by inadequate iron for normal hemoglobin production. It is a common consequence of prolonged iron depletion.
Oxygen transport: The movement of oxygen from the respiratory surface to tissues and cells. Iron-containing hemoglobin carries most oxygen in human blood.
Myoglobin: An oxygen-binding protein in muscle cells that stores and releases oxygen. Its single heme iron helps supply oxygen within muscle.
Heme iron: Dietary iron bound within heme molecules from animal tissues. Heme-bound iron follows absorption pathways distinct from most non-heme iron.

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