Haemoglobin is an iron containing metalloprotein found in the red blood cells. It is red protein carries oxygen from the lungs to the body tissues. It carries oxygen from the respiratory organs to the tissues. To the tissues it releases oxygen to allow aerobic respiration to provide energy to functioning the organism. And it also transport the carbon dioxide out of the back to the lungs. Each red blood cell contains approximately 280 million haemoglobin molecules.