Question

Up to 25% of a cell's ATP is used to run sodium-potassium pumps which transport sodium outside of the cell against its concentration gradient and potassium inside the cell against its concentration gradient. Without the resulting sodium and potassium gradients, neurons and muscles cannot function properly.

Why does phenylalanine accumulate in patients with phenylketonuria?

Answer 1

Phenylalanine accumulates in patients with phenylketonuria due to a lack of the enzyme phenylalanine hydroxylase. This accumulation interferes with the function of neurons and muscles, affecting their ability to maintain proper ion balance.

Step-by-step explanation:

Phenylalanine accumulates in patients with phenylketonuria because they lack the enzyme phenylalanine hydroxylase, which is needed to convert phenylalanine into tyrosine. As a result, phenylalanine builds up in the body and can cross the blood-brain barrier, leading to neurological damage. The accumulation of phenylalanine is detrimental to the function of neurons and muscles, as it disrupts the delicate balance of ions, including sodium and potassium, which are necessary for proper nerve and muscle function.