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

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

Question 1

Which of the following best describes the function of the sodium-potassium pump in animal cells?

Accepted Answer

It actively transports sodium ions out of the cell and potassium ions into the cell, maintaining electrochemical gradients.

Question 2

The equation for the sodium-potassium pump can be represented as $$3 \mathrm{Na}^+_{	ext{out}} + 2 \mathrm{K}^+_{	ext{in}}. $$What does this equation indicate about the pump's activity?

Accepted Answer

Three sodium ions are pumped out of the cell and two potassium ions are pumped into the cell.

Question 3

Which of the following is a direct consequence of the sodium-potassium pump's activity in neurons?

Accepted Answer

It generates a resting membrane potential by creating an electrical gradient across the membrane.

Question 4

If the sodium-potassium pump is inhibited by a toxin, what would be the most likely effect on a cell?

Accepted Answer

The cell would lose its ability to maintain osmotic balance, leading to swelling.

Question 5

Which of the following best explains why the sodium-potassium pump requires ATP?

Accepted Answer

It moves ions against their concentration gradients, which is energetically unfavorable.

Question 6

A patient is given a drug that increases the activity of the sodium-potassium pump. What is the most likely effect on the cell's membrane potential?

Accepted Answer

The membrane potential would become more negative (hyperpolarized).

Question 7

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

Accepted Answer

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

Question 8

Which of the following best describes the role of the sodium-potassium pump in maintaining cell volume?

Accepted Answer

It prevents excessive water entry by maintaining ion gradients that influence osmotic pressure.

Question 9

Which of the following statements about the sodium-potassium pump is FALSE?

Accepted Answer

It moves sodium and potassium ions in equal numbers per cycle.

Question 10

A mutation causes the sodium-potassium pump to transport only sodium ions but not potassium ions. What is the most likely cellular consequence?

Accepted Answer

The cell would accumulate sodium ions and lose potassium ions, disrupting membrane potential.

Question 11

Which of the following is a real-world example of a disease caused by malfunction of the sodium-potassium pump?

Accepted Answer

Congestive heart failure, where pump inhibition leads to altered ion gradients.

Question 12

Which of the following best explains why the sodium-potassium pump is considered electrogenic?

Accepted Answer

It creates a net movement of positive charge out of the cell, contributing to the membrane potential.

Question 13

During intense exercise, muscle cells increase their sodium-potassium pump activity. What is the physiological reason for this?

Accepted Answer

To restore ion gradients disrupted by repeated action potentials.

Question 14

Which of the following would most likely occur if a cell's sodium-potassium pump suddenly stopped working?

Accepted Answer

The cell would lose its ability to generate action potentials.

Question 15

Which of the following is the correct formula for calculating the electrochemical gradient for sodium ions across a membrane?

Accepted Answer

$$\Delta G = RT \ln \left( \frac{[\mathrm{Na}^+]_{	ext{in}}}{[\mathrm{Na}^+]_{	ext{out}}} ight) + zF\Delta \Psi$$

Question 16

Which of the following best describes secondary active transport in relation to the sodium-potassium pump?

Accepted Answer

It uses the sodium gradient established by the pump to transport other molecules against their gradients.

Question 17

Which of the following is a key difference between facilitated diffusion and the sodium-potassium pump?

Accepted Answer

Facilitated diffusion does not require ATP, while the sodium-potassium pump does.

Question 18

A cell is placed in a solution with a high concentration of potassium ions and a low concentration of sodium ions. What will the sodium-potassium pump do?

Accepted Answer

Continue to pump sodium out and potassium in, maintaining the cell's internal environment.

Question 19

Which of the following is the primary reason why the sodium-potassium pump is essential for nerve impulse transmission?

Accepted Answer

It restores ion gradients after action potentials, allowing repeated firing.

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