Question 1

Which of the following best describes the function of aquaporins in the plasma membrane?

Accepted Answer

They are channel proteins that facilitate the diffusion of water across the membrane.

Question 2

A red blood cell is placed in a hypotonic solution. What is the most likely outcome, and why?

Accepted Answer

The cell will swell and may burst because water moves into the cell.

Question 3

Which of the following is NOT a factor that affects the rate of diffusion across a cell membrane?

Accepted Answer

The amount of ATP available

Question 4

Which equation best represents the relationship between osmotic pressure ($\Pi$), solute concentration ($C$), the gas constant ($R$), and temperature ($T$)?

Accepted Answer

$\Pi = CRT$

Question 5

A patient receives an intravenous solution that is hypertonic relative to their blood plasma. What will happen to their red blood cells?

Accepted Answer

The cells will lose water and shrink (crenate).

Question 6

Which of the following best describes secondary active transport?

Accepted Answer

It relies on the concentration gradient established by primary active transport to move another substance.

Question 7

During the sodium-potassium pump cycle, what is the net movement of ions per ATP molecule hydrolyzed?

Accepted Answer

3 Na+ out, 2 K+ in

Question 8

Which of the following scenarios best illustrates facilitated diffusion?

Accepted Answer

Glucose entering a cell via a specific carrier protein without ATP.

Question 9

A cell is placed in an isotonic solution. What will happen to the cell's volume over time?

Accepted Answer

It will remain the same as water moves in and out at equal rates.

Question 10

Which of the following best explains why the cell membrane is described as 'selectively permeable'?

Accepted Answer

It allows some substances to pass while restricting others, often using specific proteins.

Question 11

Which process is illustrated by a white blood cell engulfing a bacterium?

Accepted Answer

Phagocytosis

Question 12

What is the main difference between simple diffusion and facilitated diffusion?

Accepted Answer

Facilitated diffusion requires membrane proteins, while simple diffusion does not.

Question 13

Which of the following best describes the concept of 'transport maximum' ($T_m$) in carrier-mediated transport?

Accepted Answer

It is the maximum rate of substrate transport when all carrier proteins are saturated.

Question 14

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

Accepted Answer

Pumping of Na+ out of the cell and K+ into the cell using ATP.

Question 15

A cell is actively secreting hormones into the bloodstream. Which process is primarily responsible for this secretion?

Accepted Answer

Exocytosis

Question 16

Which of the following statements about osmosis is correct?

Accepted Answer

Osmosis is the movement of water from an area of low solute concentration to high solute concentration.

Question 17

Which of the following best describes pinocytosis?

Accepted Answer

The cell takes in droplets of extracellular fluid by forming small vesicles.

Question 18

Which of the following is a characteristic of carrier-mediated transport?

Accepted Answer

It has a saturation limit, meaning there is a maximum rate of transport.

Question 19

Which of the following best explains why ions such as Na+ and K+ require channel proteins to cross the plasma membrane?

Accepted Answer

They are hydrophilic and cannot dissolve in the hydrophobic core of the membrane.

Question 20

A cell is placed in a solution and begins to swell. Which of the following best describes the tonicity of the solution relative to the cell?

Accepted Answer

The solution is hypotonic.

Cell Transport: Diffusion, Osmosis, and Membrane Dynamics

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