Why does a newborn with a genetic enzyme deficiency have a normal phenotype at birth?
A)Metabolism during prenatal life is too slow to require full enzyme activity.
B)The deficient enzyme's activity was performed by maternal enzymes before birth.
C)During the fetal phase of life, the newborn was not exposed to the protein that the enzyme is responsible for degrading.
D)Although the newborn cannot synthesize the enzyme after birth, the initially stored enzyme performs its functions until the level is fully depleted.

Question

Quizplus · Accepted Answer

The newborn with a genetic enzyme deficiency does not have symptoms of the deficiency at birth. The reason that symptoms often are not apparent in the newborn is that the maternal enzymes cross the placenta and perform their specific functions in the cells of the fetus. When the child is born, its access to effective maternal enzymes stops, and the enzyme deficiency begins to affect the child's metabolism.

Why Does a Newborn with a Genetic Enzyme Deficiency Have