Question

What part of haemoglobin is affected in sickle cell anaemia?

Options

• α-polypeptide chains.

• β-polypeptide chains.

• Both α- and β-polypeptide chains.

• None of the above.

Answer 1

β-polypeptide chains

Explanation:

Because sickle cell anaemia is caused by a mutation specifically in the β-polypeptide chains of the haemoglobin molecule. In this condition, a single amino acid error occurs where glutamic acid is replaced by valine at the sixth position of the beta chain. This small change causes the haemoglobin to clump together, forcing red blood cells into a stiff, sickle shape that can block blood flow.