Question

Which one of the following disorders is caused by the substitution of Glutamic acid (Glu) by Valine (Val) at the sixth position of the beta globin chain of the haemoglobin molecule?

• A. Thalassemia
• B. Haemophilia
• C. Sickle-cell anaemia
• D. Phenylketonuria

Hint:

To remember the mutation: Glu (Good) becomes Val (Vile) at position 6 because of a change from A to U in the codon.

Answer 1

The Correct Option is C

Step 1 : Understanding the Question
Identify the disorder caused by a specific point mutation in hemoglobin.
Step 2 : Key Formulas and approach
$\text{GAG (Glu)} \rightarrow \text{GUG (Val)}$.
Step 3 : Detailed Explanation

The Mutation: (A) Sickle-cell anaemia involves replacing Glu with Val.

Position: This occurs at the 6th position of the beta chain.

Effect: RBCs become (B) sickle-shaped under low oxygen.

Step 4 : Final Answer
Correct answer is Sickle-cell anaemia (B).