Explain why haemoglobin in Sickle Cell Anaemia is less effective at carrying oxygen.

The mutation present in sickle cell anaemia causes a change in the primary structure of amino acids in the haemoglobin molecule. This change in primary structure changes the tertiary structure of a haemoglobin peptide chain meaning that its unique 3D shape is different. This change in shape means that the molecule is less complementary to oxygen molecules making association harder.