Haemoglobin in the red blood cells carries oxygen from the lungs to the tissues. It delivers the oxygen molecule to myoglobin in the tissues. When the oxygen has been released for cell respiration, haemoglobin loses its bright red colour and becomes purple. It then combines with the waste carbon dioxide produced by the cells and deposits in the lungs so that the gas can be exhaled.
Coordination compounds play an important role in many biological processes in plants and animals.
Functions of Haemoglobin: Transport and storage of oxygen.