Carriage of oxygen

Haemoglobin

• Oxygen is transported in erythrocytes- contain haemoglobin
• When haemoglobin takes up oxygen it becomes oxyhaemoglobin
• H- complex protein with 4 subunits- each subunit consists of a polypeptide (protein) chain & a haem (non protein) group
• The haem group contains a single iron atom in the form of Fe2+ - can attract & hold an O2
• Therefore, haemoglobin can hold up to 4 oxygen molecules 

Taking up oxygen

• Oxygen is absorbed into the blood in the lungs
• Oxygen molecules diffusing into the blood plasma enter the erythrocytes- here they are taken up by H
• …