Multiple choice

Phenylketonuria is caused by a defect in the gene for an enzyme that converts:

  1. Tyrosine to phenylalanine causing a buildup of phenylalanine

  2. Phenylalanine to tyrosine causing a buildup of phenylalanine

  3. Phenylalanine to tyrosine causing a buildup of tyrosine

  4. Tyrosine to phenylalanine causing a buildup of tyrosine

Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

PKU is caused by a deficiency of the enzyme phenylalanine hydroxylase. This enzyme is responsible for converting the amino acid phenylalanine into tyrosine.