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Sickle cell anaemia is due to : -
A
Change of amino acid in $\alpha$-chain of haemoglobin
B
Change of amino acid in $\beta$-chain of haemoglobin
C
Change of amino acid in both $\alpha$ and $\beta$ chains of haemoglobin
D
Change of amino acid in either $\alpha$ or $\beta$ chain of haemoglobin
Detailed Solution
Haemoglobin has two $\alpha$ and two $\beta$ polypeptide chains.
In sickle cell anaemia, a point mutation in the $\beta$-globin gene (GAG $\rightarrow$ GUG in the codon) replaces glutamic acid by valine at the sixth position of the $\beta$ chain.
The resulting HbS polymerises at low oxygen, making the RBCs sickle shaped.
So sickle cell anaemia is due to change of an amino acid in the $\beta$-chain of haemoglobin.
In sickle cell anaemia, a point mutation in the $\beta$-globin gene (GAG $\rightarrow$ GUG in the codon) replaces glutamic acid by valine at the sixth position of the $\beta$ chain.
The resulting HbS polymerises at low oxygen, making the RBCs sickle shaped.
So sickle cell anaemia is due to change of an amino acid in the $\beta$-chain of haemoglobin.