Question 1

Which part of a neuron is primarily responsible for receiving incoming signals from other neurons?

Accepted Answer

Dendrite

Question 2

Which of the following best describes the composition of the cell membrane and its selective permeability?

Accepted Answer

It is made of a phospholipid bilayer with embedded proteins, and large or charged molecules cannot pass through easily.

Question 3

Which type of transport across the cell membrane requires energy in the form of ATP?

Accepted Answer

Active transport

Question 4

What is the main function of ATP in neuron activity?

Accepted Answer

To supply energy for active transport of ions across the membrane

Question 5

During the resting potential of a neuron, which of the following best describes the distribution of ions and charges across the membrane?

Accepted Answer

The inside of the neuron is negative relative to the outside, with more K$^+$ inside and more Na$^+$ outside.

Question 6

Which protein is primarily responsible for restoring the resting membrane potential after an action potential?

Accepted Answer

Na$^+$/K$^+$ ATPase pump

Question 7

Why is it more difficult for a neuron to fire a second action potential immediately after the first one?

Accepted Answer

The neuron is hyperpolarized due to the continued efflux of K$^+$, creating a refractory period.

Question 8

How do myelin and the Nodes of Ranvier affect the speed of action potential transmission along an axon?

Accepted Answer

They allow the action potential to jump from node to node, increasing speed (saltatory conduction).

Question 9

A neurotoxin blocks voltage-gated Na$^+$ channels in neurons. What is the most likely effect on the nervous system?

Accepted Answer

Paralysis due to inability to generate action potentials

Question 10

Which of the following best describes the process by which an action potential is converted into a chemical signal at a synapse?

Accepted Answer

The action potential causes voltage-gated Ca$^{2+}$ channels to open, leading to neurotransmitter release.

Question 11

Which of the following mechanisms is NOT involved in clearing neurotransmitters from the synaptic cleft?

Accepted Answer

Active transport of neurotransmitters into the postsynaptic neuron

Question 12

Which of the following best distinguishes an excitatory postsynaptic potential (EPSP) from an inhibitory postsynaptic potential (IPSP)?

Accepted Answer

EPSPs depolarize the postsynaptic membrane, increasing the likelihood of an action potential, while IPSPs hyperpolarize it, decreasing the likelihood.

Question 13

A patient is exposed to a drug that inhibits the reuptake of neurotransmitters from the synaptic cleft. What is the most likely effect?

Accepted Answer

Prolonged activation of the postsynaptic neuron

Question 14

Which of the following best explains why large polar molecules cannot easily cross the cell membrane?

Accepted Answer

They are repelled by the hydrophobic core of the phospholipid bilayer.

Question 15

Which of the following scenarios would most likely result in seizures rather than paralysis?

Accepted Answer

A drug that prevents the breakdown of excitatory neurotransmitters in the synaptic cleft

Question 16

Which of the following is a correct sequence of events during the generation of an action potential?

Accepted Answer

Depolarization by Na$^+$ influx, repolarization by K$^+$ efflux

Question 17

A mutation causes the Na$^+$/K$^+$ ATPase pump to stop functioning. What would be the immediate effect on the neuron's membrane potential?

Accepted Answer

The membrane potential would gradually approach zero as ion gradients dissipate.

Question 18

Which of the following best describes the role of passive transport proteins in neurons?

Accepted Answer

They allow ions to move down their concentration gradients without using energy.

Question 19

A patient is diagnosed with multiple sclerosis, a disease that damages the myelin sheath. Which of the following symptoms is most directly related to this damage?

Accepted Answer

Slower nerve signal transmission and muscle weakness

Nervous System: Structure, Function, and Signal Transmission

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