ABSTRACT
The carriage of oxygen from the lungs to the rest of the body, and carbon dioxide back to the lungs is essential for life. Oxygen is carried in the blood by haemoglobin (Hb), which is found in red blood cells in the blood. A single molecule of adult haemoglobin (HbA) in the adult consists of four polypeptide chains (two alpha chains and two beta chains), each with its own haem molecule. A molecule of haem is made from the combination of protoporphyrin to an atom of iron.
