Question

Assertion :Phenylketonuria and sickle-cell anaemia are autosomal recessive traits disorder.
Reason: In phenylketonuria due to lacks of phenylalanine hydroxylase AA-tyrosine is converted into phenylalanine (AA) while in sickle-cell anaemia valine is replaced by glutamic acid in $\beta$ chain.

• A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
• B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
• C. Assertion is correct but Reason is incorrect
• D. Both Assertion and Reason are incorrect

Answer 1

The correct option is A Both Assertion and Reason are correct and Reason is the correct explanation for Assertion

Both phenylketonuria and sickle cell anaemia are autosomal recessive traits disorder. Phenylketonuria, a recessive metabolic disorder is caused due to lack of enzyme phenylalanine hydroxylase which converts phenylalanine to tyrosine in the liver. So there is an accumulation of phenylalanine in the liver resulting In hyperphenylalaninemia and is characterized by excretion of phenylalanine with the related compound in urine.

In sickle cell anaemia , in the beta chain of Hb, the sixth position occupied of amino acid glutamic acid is replaced by valine. This causes the change in morphology of RBC and haemolytic anaemia .

Hence correct answer is option A.