Which amino acid is substituted in sickle cell anaemia? A. Glutamic acid by valine at the 6th position in α- chain B. Glutamic acid by valine at the 6th position in ß-chain C. Valine by glutamic acid at the 4th position in α- chain D. Valine by glutamic acid at the 4th position in ß-chain
Option B Sickle cell disease is associated with the inversion of one base pair (A = T → A = T). The sixth codon of the beta globin chain [GAA] becomes [GTA]. Accordingly, the sixth amino acid (glutamic acid, negatively charged) is replaced by valine, hydrophobic.
