Q: What is the main function of the sodium-potassium pump in maintaining the resting potential of a neuron?

It uses ATP to pump three Na\textsuperscript{+} ions out of the cell for every two K\textsuperscript{+} ions in.

Q: During an action potential, what event directly causes the membrane potential to become more positive (depolarization)?

Opening of sodium channels and Na\textsuperscript{+} ions entering the cell

Q: If a neuron’s membrane potential reaches the threshold of $-50\ \mathrm{mV}$, what is the next event that occurs?

Sodium channels open and Na\textsuperscript{+} rushes in

Q: Which of the following equations correctly represents the net movement of ions by the sodium-potassium pump per ATP hydrolyzed?

$3\ \mathrm{Na}^+_{\text{out}} + 2\ \mathrm{K}^+_{\text{in}}$

Question 1

Which part of a neuron is primarily responsible for transmitting information toward the cell body?

Accepted Answer

Dendrite

Question 2

What is the main function of the sodium-potassium pump in maintaining the resting potential of a neuron?

Accepted Answer

It uses ATP to pump three Na	extsuperscript{+} ions out of the cell for every two K	extsuperscript{+} ions in.

Question 3

During an action potential, what event directly causes the membrane potential to become more positive (depolarization)?

Accepted Answer

Opening of sodium channels and Na	extsuperscript{+} ions entering the cell

Question 4

If a neuron’s membrane potential reaches the threshold of $-50\ \mathrm{mV}$, what is the next event that occurs?

Accepted Answer

Sodium channels open and Na	extsuperscript{+} rushes in

Question 5

Which of the following best describes the process of exocytosis in a neuron?

Accepted Answer

The fusion of vesicles with the plasma membrane to release neurotransmitters

Question 6

A poison that holds sodium channels open in neurons would most likely cause which of the following?

Accepted Answer

Convulsions due to persistent depolarization

Question 7

Which of the following equations correctly represents the net movement of ions by the sodium-potassium pump per ATP hydrolyzed?

Accepted Answer

$3\ \mathrm{Na}^+_{	ext{out}} + 2\ \mathrm{K}^+_{	ext{in}}$

Question 8

A neurotransmitter binds to a receptor on the postsynaptic membrane and causes Na	extsuperscript{+} channels to open. What is the likely effect on the postsynaptic cell?

Accepted Answer

It becomes depolarized and more likely to fire an action potential.

Question 9

Which of the following best explains why grasshopper mice do not feel pain from scorpion venom, while lab mice do?

Accepted Answer

Grasshopper mice have sodium channels in pain receptors that do not open in response to the venom.

Question 10

Which of the following is a correct sequence of events for the release of a neurotransmitter at a synapse?

Accepted Answer

Action potential arrives at axon terminal $\rightarrow$ calcium channels open $\rightarrow$ vesicles fuse with membrane $\rightarrow$ neurotransmitter released

Question 11

Which of the following best describes the role of the endomembrane system in a mammary gland cell secreting milk proteins?

Accepted Answer

Proteins are synthesized in the rough ER, processed in the Golgi apparatus, and secreted via vesicles through exocytosis.

Question 12

Which of the following would most likely result from blocking acetylcholinesterase at a neuromuscular junction?

Accepted Answer

Muscle contraction would be prolonged due to persistent acetylcholine in the synaptic cleft.

Question 13

A neuron receives both excitatory and inhibitory inputs at the same time. What determines whether it will fire an action potential?

Accepted Answer

The sum of all excitatory and inhibitory signals (synaptic integration)

Question 14

Which of the following best describes the direction of information flow in a typical neuron?

Accepted Answer

Dendrite $\rightarrow$ cell body $\rightarrow$ axon

Question 15

Which of the following is a real-world example of a drug affecting neurotransmitter concentration in the synaptic cleft?

Accepted Answer

Serotonin reuptake inhibitors block the reuptake of serotonin, increasing its concentration in the synapse.

Question 16

Which of the following best explains why action potentials are described as 'all-or-nothing' events?

Accepted Answer

Once threshold is reached, an action potential of fixed size is generated.

Question 17

What is the primary effect of an inhibitory neurotransmitter on the postsynaptic cell?

Accepted Answer

It decreases the likelihood of an action potential.

Question 18

Which of the following best describes the process of saltatory conduction in myelinated axons?

Accepted Answer

Action potentials jump from one node of Ranvier to the next, increasing conduction speed.

The Nervous System: Structure, Function, and Cellular Communication

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