Question 1

Which of the following best describes passive transport across a cell membrane?

Accepted Answer

Movement of molecules from high to low concentration, does NOT require ATP.

Question 2

Facilitated diffusion differs from simple diffusion in that:

Accepted Answer

Facilitated diffusion involves carrier proteins or channels specific for certain molecules.

Question 3

Which of the following is TRUE regarding aquaporins?

Accepted Answer

Aquaporins are channels that facilitate the diffusion of water across the cell membrane.

Question 4

Carrier-mediated facilitated diffusion exhibits saturation because:

Accepted Answer

Carrier proteins have a maximum rate when all binding sites are occupied.

Question 5

Which equation correctly represents the hydrolysis of ATP during primary active transport?

Accepted Answer

$ATP \rightarrow ADP + P_i$

Question 6

The Na+/K+ pump moves:

Accepted Answer

3 Na+ out of the cell and 2 K+ into the cell per ATP hydrolyzed.

Question 7

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

Accepted Answer

Movement of glucose into a cell using the Na+ gradient established by the Na+/K+ pump.

Question 8

In the context of carrier-mediated transport, competition occurs when:

Accepted Answer

Multiple molecules compete for the same carrier protein.

Question 9

Which of the following statements about the Ca2+ pump is correct?

Accepted Answer

It uses ATP to pump Ca2+ out of the cytoplasm into the extracellular fluid or into the smooth endoplasmic reticulum.

Question 10

Which process is responsible for the movement of water across a cell membrane?

Accepted Answer

Osmosis through aquaporins.

Question 11

A cell is placed in a solution with a higher concentration of glucose than inside the cell. Which transport mechanism will most likely be used to move glucose into the cell?

Accepted Answer

Facilitated diffusion via a glucose carrier protein.

Question 12

Which of the following best describes cotransport (symport) in secondary active transport?

Accepted Answer

Two molecules are transported in the same direction across the membrane.

Question 13

Bulk transport mechanisms such as endocytosis and exocytosis are primarily used for:

Accepted Answer

Moving large molecules or particles into or out of the cell.

Question 14

Which of the following is NOT a characteristic of facilitated diffusion?

Accepted Answer

It requires ATP hydrolysis.

Question 15

If the concentration of a solute outside the cell is higher than inside, and the solute is polar and large, which transport mechanism is most likely to be used?

Accepted Answer

Facilitated diffusion through a specific carrier protein.

Question 16

Which of the following best explains why increasing the concentration of a substrate does NOT increase the transport rate beyond a certain point in carrier-mediated transport?

Accepted Answer

All carrier proteins are saturated and working at maximum capacity.

Question 17

Which of the following is a direct result of the Na+/K+ pump activity in neurons?

Accepted Answer

Establishment of a concentration gradient for Na+ and K+ across the membrane.

Question 18

Which of the following equations represents the coupled transport of glucose and Na+ into a cell?

Accepted Answer

$Glucose_{(out)} + Na^+_{(out)} \rightarrow Glucose_{(in)} + Na^+_{(in)}$

Question 19

Which of the following statements about secondary active transport is correct?

Accepted Answer

ATP is used indirectly by establishing a gradient that drives the transport of another molecule.

Cell Membrane Transport Mechanisms: Passive and Active Transport

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