Q: A patient is given a drug that blocks all ATP production in their cells. Which of the following transport processes would be most directly affected?

Primary active transport of sodium and potassium by the Na\textsuperscript{+}/K\textsuperscript{+} ATPase

Q: Which equation correctly represents Fick’s Law of Diffusion for the net flux ($J$) of a solute across a membrane?

$J = P \times A \times \Delta C$

Q: A cell is placed in a solution with a much higher concentration of potassium ions (K\textsuperscript{+}) outside than inside. If the membrane is only permeable to K\textsuperscript{+}, what will happen?

K\textsuperscript{+} will move into the cell by passive diffusion.

Q: A mutation causes a cell to lack functional Na\textsuperscript{+}/K\textsuperscript{+} ATPase pumps. Which of the following is a likely consequence?

The cell will accumulate Na\textsuperscript{+} inside and lose K\textsuperscript{+} to the outside.

Question 1

Which of the following best describes the main difference between passive and active transport across the cell membrane?

Accepted Answer

Passive transport moves substances toward equilibrium without energy input, while active transport moves substances away from equilibrium and requires energy input.

Question 2

A patient is given a drug that blocks all ATP production in their cells. Which of the following transport processes would be most directly affected?

Accepted Answer

Primary active transport of sodium and potassium by the Na	extsuperscript{+}/K	extsuperscript{+} ATPase

Question 3

Which equation correctly represents Fick’s Law of Diffusion for the net flux ($J$) of a solute across a membrane?

Accepted Answer

$J = P 	imes A 	imes \Delta C$

Question 4

Which of the following molecules is most likely to cross the cell membrane by simple diffusion?

Accepted Answer

Oxygen (O$_2$)

Question 5

A cell is placed in a solution with a much higher concentration of potassium ions (K	extsuperscript{+}) outside than inside. If the membrane is only permeable to K	extsuperscript{+}, what will happen?

Accepted Answer

K	extsuperscript{+} will move into the cell by passive diffusion.

Question 6

Which of the following best explains why facilitated diffusion exhibits a maximum rate of transport (saturation)?

Accepted Answer

All carrier proteins become occupied and cannot transport additional molecules until they are free.

Question 7

A mutation causes a cell to lack functional Na	extsuperscript{+}/K	extsuperscript{+} ATPase pumps. Which of the following is a likely consequence?

Accepted Answer

The cell will accumulate Na	extsuperscript{+} inside and lose K	extsuperscript{+} to the outside.

Question 8

Which of the following scenarios best illustrates secondary active transport?

Accepted Answer

Glucose is transported into a cell against its concentration gradient, powered by the movement of Na	extsuperscript{+} down its gradient.

Question 9

Which of the following would increase the rate of simple diffusion of a solute across a membrane, according to Fick’s Law?

Accepted Answer

Increasing the membrane permeability ($P$)

Question 10

A patient with a genetic defect in aquaporin channels is likely to have problems with which process?

Accepted Answer

Osmosis of water across cell membranes

Question 11

Which of the following best describes the electrochemical driving force for an ion?

Accepted Answer

It is the sum of the chemical (concentration) and electrical (charge) gradients acting on the ion.

Question 12

Which of the following is an example of countertransport (antiport) in secondary active transport?

Accepted Answer

Na	extsuperscript{+} moving into the cell while H	extsuperscript{+} is transported out of the cell

Question 13

A cell is placed in a solution where the external concentration of a solute is much higher than inside, but the solute cannot cross the membrane. What will happen to the water movement?

Accepted Answer

Water will move out of the cell by osmosis.

Question 14

Which of the following statements about epithelial transport is correct?

Accepted Answer

Water transport across epithelia is usually secondary to solute transport.

Question 15

If the number of carrier proteins for glucose in a cell membrane is rapidly increased, what will happen to the rate of glucose uptake (assuming a constant concentration gradient)?

Accepted Answer

It will increase until the carriers become saturated.

Question 16

Which of the following best explains why ions such as Na	extsuperscript{+} and K	extsuperscript{+} require channels or carriers to cross the cell membrane?

Accepted Answer

They are charged and cannot pass through the hydrophobic core of the lipid bilayer.

Question 17

A researcher measures the net flux of a solute across a membrane and finds it is zero, even though there is a concentration gradient. Which of the following could explain this observation?

Accepted Answer

The membrane is impermeable to the solute.

Question 18

Which of the following is true regarding the Na	extsuperscript{+}/K	extsuperscript{+} ATPase pump?

Accepted Answer

It requires ATP to function.

Question 19

Which of the following would most likely decrease the rate of facilitated diffusion of a solute?

Accepted Answer

Decreasing the concentration gradient

Cell Membrane Transport: Mechanisms and Principles

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