Question 1

Which of the following best describes a selectively-permeable membrane?

Accepted Answer

A membrane that allows certain substances to pass while restricting others based on specific properties.

Question 2

A red blood cell is placed in a solution and swells until it bursts. Which term best describes the solution?

Accepted Answer

Hypotonic

Question 3

Which of the following factors would most likely increase the rate of diffusion across a cell membrane?

Accepted Answer

Increasing the concentration gradient

Question 4

Which equation correctly represents the Nernst equation for calculating the equilibrium potential ($E_{ion}$) for a monovalent cation?

Accepted Answer

$E_{ion} = \frac{RT}{zF} \ln \left( \frac{[ion]_{out}}{[ion]_{in}} \right)$

Question 5

A patient is given an intravenous solution containing a high concentration of NaCl. What effect will this have on their red blood cells?

Accepted Answer

The cells will shrink due to water leaving the cell.

Question 6

Which of the following best explains why glucose requires a carrier protein to cross the cell membrane?

Accepted Answer

Glucose is a large, polar molecule that cannot diffuse through the lipid bilayer.

Question 7

Which of the following is an example of primary active transport?

Accepted Answer

Sodium-potassium pump ($Na^+/K^+$ ATPase)

Question 8

If the extracellular concentration of $K^+$ is decreased, what effect will this have on the resting membrane potential of a neuron?

Accepted Answer

The resting membrane potential will become more negative (hyperpolarized).

Question 9

Which of the following best describes facilitated diffusion?

Accepted Answer

Movement of molecules down their concentration gradient with the help of a carrier protein, without energy input.

Question 10

A cell is placed in a solution containing a non-permeable solute at a higher concentration than inside the cell. Which process will occur?

Accepted Answer

Water will move out of the cell by osmosis.

Question 11

Which of the following ions has the greatest influence on the resting membrane potential of most cells?

Accepted Answer

Potassium ($K^+$)

Question 12

Which of the following best explains the difference between active and passive transport?

Accepted Answer

Active transport requires energy input, while passive transport does not.

Question 13

A neuron is exposed to a toxin that blocks voltage-gated sodium channels. What is the most likely effect on the neuron’s ability to generate an action potential?

Accepted Answer

The neuron will be unable to depolarize and generate an action potential.

Question 14

Which of the following best describes the role of carrier-mediated transport in the absorption of glucose from the intestine?

Accepted Answer

Glucose is absorbed by facilitated diffusion and secondary active transport.

Question 15

Which of the following statements about the sodium-potassium pump ($Na^+/K^+$ ATPase) is correct?

Accepted Answer

It moves 3 $Na^+$ ions out of the cell and 2 $K^+$ ions in, using ATP.

Question 16

Which of the following would most likely decrease the permeability of a cell membrane to sodium ions?

Accepted Answer

Blocking sodium channels with a specific toxin

Question 17

A patient has a genetic defect that causes their cell membranes to lack aquaporins. Which process would be most directly affected?

Accepted Answer

Osmosis of water

Question 18

Which of the following best explains why the resting membrane potential is negative in most cells?

Accepted Answer

The sodium-potassium pump moves more positive charges out than in.

Question 19

Which of the following is a correct statement about the distribution of major ions in the intracellular and extracellular fluids?

Accepted Answer

The concentration of $Na^+$ is higher outside the cell, while $K^+$ is higher inside.

Question 20

A cell is exposed to a drug that increases the number of open potassium channels. What is the most likely effect on the membrane potential?

Accepted Answer

The membrane potential will become more negative (hyperpolarized).

Movement of Molecules Through the Cell Membrane and Development of Membrane Potential

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