What Genetic Disorder Is Associated with the Lack of an Enzyme

question 17

Multiple Choice

What genetic disorder is associated with the lack of an enzyme necessary for the normal metabolism of the amino acid phenylalanine?

• A) Phenylketonuria (PKU)
• B) Marfan syndrome
• C) Huntington disease
• D) Sickle cell disease
• E) Cystic fibrosis (CF)

---

Definitions:

Afferent Neurons

Nerve cells that carry sensory information from the body's tissues and organs towards the central nervous system.

Efferent Neurons

Nerve cells that convey impulses away from the central nervous system to effectors, such as muscles or glands.

Synaptic Gap

The tiny space between neurons across which neurotransmitters travel to carry signals from one neuron to another.

Axon Terminal

The very end of the axon of a neuron, where neurotransmitters are released to communicate with other neurons.