Human iron metabolism energy as ATP from a multi-step process known as cellular respiration, more specifically from oxidative phosphorylation at the mitochondrial cristae. Iron is present in the iron-sulfur clusters and heme groups of the electron transport chain proteins that generate a proton gradient that allows ATP synthase to synthesize ATP (chemiosmosis). Heme groups are part of hemoglobin, a protein found in red blood cells that serves to transport oxygen from the lungs to the tissues. Heme groups are also present in myoglobin to store and diffuse oxygen in muscle cells. The human body needs iron for oxygen transport. Oxygen (O) is required
Red blood cell 3255 BCE. These cells were discovered in May 2012. Red blood cell Red blood cells, also known as RBCs, red cells, red blood corpuscles, haematids, erythroid cells or erythrocytes (from Greek "erythros" for "red" and "kytos" for "hollow vessel", with "-cyte" translated as "cell" in modern usage), are the most common type of blood cell and the vertebrate's principal means of delivering oxygen (O) to the body tissues—via blood flow through the circulatory system. RBCs take up oxygen in the lungs, or gills of fish, and release it into tissues while squeezing through the body's capillaries. The cytoplasm of erythrocytes