In sickle cell anaemia, the basis of malfunction of haemoglobin molecules isA. reduced affinity for oxygenB. incorrect secondary structureC. substitution of glutamic acid residue by valineD. faulty binding of the heme group

In sickle cell anaemia, the basis of malfunction of haemoglobin molecu

1.	In sickle cell anaemia, the basis of malfunction of haemoglobin molecules isA. reduced affinity for oxygenB. incorrect secondary structureC. substitution of glutamic acid residue by valineD. faulty binding of the heme group
Answer» Correct Answer - C The genetically based disease sickle - cell anemia results from a single amino acid error in the `beta`-chain of haemoglobin. In normal haemoglobin, position 6 has a glutamic acid residue, whereas in sickle - cell haemoglobin position 6 is occupied by valine. Red blood cells (erythrocytes) containing haemoglobin with this amino acid residue error tend to become crescent shaped ("sickle") when the partial pressure of oxygen is low, as it is in venous blood. These distorted cells are more difficult for the heart to pump through small capillaries. They may even block capillaries by clumping together, at other times the red cells may even split open. Children who inherit genetic trait from their parents suffer from a severe form of the disease and usually do not live past the age of two.