Q: Which equation best represents the action of the sodium-potassium pump as shown in panel B?

$$3\ \mathrm{Na}^+_{\text{in}} + 2\ \mathrm{K}^+_{\text{out}} + \mathrm{ATP} \rightarrow 3\ \mathrm{Na}^+_{\text{out}} + 2\ \mathrm{K}^+_{\text{in}} + \mathrm{ADP} + \mathrm{P}_i$$

Question 1

Which of the following best describes the primary function of the sodium-potassium pump as illustrated in panel B?

Accepted Answer

It actively transports 3 Na$$^+$$ out of the cell and 2 K$$^+$$ into the cell using ATP.

Question 2

According to the diagram in panel A, which ions are found in higher concentration outside the neuron at rest?

Accepted Answer

Na$$^+$$ and Cl$$^-$$

Question 3

Panel D shows two states of an ion channel. What is the main difference between these two states?

Accepted Answer

One state allows ions to pass through, while the other does not.

Question 4

If a mutation caused the sodium-potassium pump to stop functioning, what would be the most immediate effect on the neuron?

Accepted Answer

The resting membrane potential would dissipate as Na$$^+$$ and K$$^+$$ gradients equalize.

Question 5

Which equation best represents the action of the sodium-potassium pump as shown in panel B?

Accepted Answer

$$3\ \mathrm{Na}^+_{	ext{in}} + 2\ \mathrm{K}^+_{	ext{out}} + \mathrm{ATP} ightarrow 3\ \mathrm{Na}^+_{	ext{out}} + 2\ \mathrm{K}^+_{	ext{in}} + \mathrm{ADP} + \mathrm{P}_i$$

Question 6

Panel C shows the structure of a neuron. Which part is primarily responsible for receiving synaptic input from other neurons?

Accepted Answer

Dendrite

Question 7

Leak channels, as described in panel B, are more permeable to which ion?

Accepted Answer

K$$^+$$

Question 8

If the leak channels for K$$^+$$ were blocked, what would happen to the resting membrane potential?

Accepted Answer

It would become less negative (depolarized).

Question 9

Which of the following best explains why the inside of a neuron is negatively charged relative to the outside at rest?

Accepted Answer

Leak channels allow more K$$^+ to $$leave the cell than Na$$^+ to $$enter.

Question 10

A drug blocks the opening of gated ion channels as shown in panel D. What is the most likely effect on neuronal signaling?

Accepted Answer

The neuron would be unable to generate action potentials.

Question 11

Which of the following is a direct result of the sodium-potassium pump's activity?

Accepted Answer

Establishment of a negative resting membrane potential.

Question 12

If extracellular K$$^+$$ concentration increases significantly, what is the most likely effect on the neuron?

Accepted Answer

The resting membrane potential becomes less negative.

Question 13

Which of the following best describes the role of gated ion channels as shown in panel D?

Accepted Answer

They allow ions to move only when open, contributing to changes in membrane potential.

Question 14

Which process is illustrated by the movement of ions through leak channels as shown in panel B?

Accepted Answer

Facilitated diffusion

Question 15

A neuron is exposed to a toxin that permanently opens all Na$$^+$$ channels. What is the most likely outcome?

Accepted Answer

The neuron will depolarize and may not be able to repolarize.

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