Certain essential amino acids that are needed for brain function but do not have properties for passive diffusion:
A) require biotransformation before they can enter the brain.
B) are synthesized by neurons.
C) must enter the brain through active transport mechanisms.
D) are synthesized by glial cells.

Question

Quizplus · Accepted Answer

Certain essential amino acids, such as phenylalanine, tryptophan, and tyrosine, cannot passively diffuse across the blood-brain barrier. Instead, they require active transport mechanisms such as carrier-mediated transport or receptor-mediated transport to cross into the brain. This is because the blood-brain barrier serves as a selective filtration system, allowing only certain molecules to enter while keeping potentially harmful substances out.

Certain Essential Amino Acids That Are Needed for Brain Function