red blood cells

• red blood cells carry oxygen
• shape is a biconcave disc giving a larger surface area for absorbing oxygen
• red blood cells dont have a nucleus
• contain the oxygen carrying molecule haemoglobin
• in the lungs haemoglobin binds to oxygen to become oxyhaemoglobin
• in body tissues oxyhaemoglobin splits into haemoglobin and oxygen to release oxygen to the cells