Question

Assertion : Phenylketonuria, Haemophilia and sickle cell anemia are genetic disorders.
Reason : In phenylketonuria the person has a non-functional enzyme for the conversion of phenylalanine to tyrosine.

• A. If both assertion and reason are true and reason is the correct explanation of assertion.
• B. If both assertion and reason are true but reason is not the correct explanation of assertion.
• C. If assertion is true but reason is false.
• D. If both assertion and reason are false.

Answer 1

Answer: (B)

Phenylketonuria is an inborn error of metabolism inherited as the autosomal recessive trait. The affected individual lacks an enzyme that converts the amino acid phenylalanine into tyrosine. As a result of this, phenylalanine is accumulated and converted into phenylpyruvic acid and other derivatives. Accumulation of these in brain results in mental retardation. These are also excreted through urine because of its poor absorption by kidney. In order to lesson the suffering of phenylketonurics, their diet should have low phenylalanine and normal requirement of tyrosine.