1. Which manifestation is a characteristic feature of untreated phenylketonuria (PKU)?
A. Increased skin pigmentation
B. Excessive urination
C. Fragile bones
D. Small stature
2. What is the expected result of a deficiency in the enzyme phenylalanine hydroxylase (PAH)?
A. High levels of phenylalanine; low levels of tyrosine
B. High levels of phenylalanine; high levels of tyrosine
C. Low levels of phenylalanine; low levels of tyrosine
D. Low levels of phenylalanine; high levels of tyrosine
3. Which substance fails to form normally in individuals with Marfan syndrome?
A. Elastin
B. Glycogen
C. Collagen
D. Fibrillin
