oxyhaemoglobin

• red blood cells contain oxyhaemoglobin which is a protein that carries oxygen
• Haemoglobin is a large protein with a quaternary structure and is made up from more than 1 polypeptide chain
• each polypeptide chain has a haem group which contains iron and gives the haemoglobin its red colour
• haemoglobin has a high affinity for oxygen - each molecule can carry 4 oxygen molecules
• in the lungs, oxygen joins to the iron in haemoglobin to form oxyhaemoglobin this is a reversable reaction - when oxygen leaves oxyhaemoglobin near the body cells, it turns back into haemoglobin