Answer:
The sickle cell anemia occurs due to the point mutation in the beta globin chain. The valine is replaced by the glutamic acid at sixth position that results in the change in shape and size of the red blood cells.
The sickle blood cells have sickle cells as compared with the normal blood cells that are concave in shape. These cells become hydrophobic and the molecules gets stick with the blood cells. The oxygen binding capacity decreases and the sticky nature of the cells can form clot in the body.