Biological Systems MCAT Practice Exam

What does the cell body of a neuron contain?

1. Dendrites and axon

2. Nucleus and soma

3. Myelin sheath

4. Synaptic knobs

The correct answer is: Nucleus and soma

The cell body of a neuron, also known as the soma, contains the nucleus and essential organelles necessary for the cell's functions. The nucleus houses the cell's genetic material and is responsible for regulating gene expression and maintaining the cell's health. The soma also contains various organelles, such as ribosomes, endoplasmic reticulum, and mitochondria, which are crucial for protein synthesis and energy production. While other components of a neuron play important roles in its overall function, they are not part of the cell body itself. Dendrites and axons, for example, are extensions that emanate from the cell body and are involved in receiving and transmitting signals, respectively. The myelin sheath acts as an insulating layer around the axon and enhances signal transmission but is not contained within the cell body. Synaptic knobs, located at the end of axons, are the sites of neurotransmitter release but are also not part of the cell body. Thus, the accurate identification of the nucleus and soma as components of the cell body solidifies the understanding of neuron structure and function.