Question 1

Which of the following best describes the chemical driving force for the movement of a solute across a cell membrane?

Accepted Answer

It is determined by the difference in solute concentration across the membrane.

Question 2

A cell is placed in a solution containing 0.2 M NaCl. What is the osmolarity of this solution?

Accepted Answer

$0.4 \, 	ext{Osm}$

Question 3

Which of the following scenarios would result in the greatest net flux of a solute across a membrane by simple diffusion?

Accepted Answer

A large concentration gradient and high membrane permeability

Question 4

The equilibrium potential for potassium ($E_K$) is $-94 \, 	ext{mV}$. If the membrane potential ($V_m$) is $-70 \, 	ext{mV}$, what is the direction of the electrochemical driving force for $K^+$?

Accepted Answer

Out of the cell

Question 5

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

Accepted Answer

Transport rate can reach a maximum due to carrier saturation

Question 6

A patient with diabetes mellitus has high plasma glucose levels. Why do their cells shrink?

Accepted Answer

Glucose is impermeant to cells, increasing plasma tonicity and causing water to leave the cells.

Question 7

Which of the following best explains why the Na+/K+ pump is considered primary active transport?

Accepted Answer

It directly uses ATP to move ions against their electrochemical gradients.

Question 8

If a cell is placed in a hyperosmotic solution, what will happen to the cell volume?

Accepted Answer

The cell will shrink as water leaves the cell.

Question 9

Which of the following is true regarding secondary active transport?

Accepted Answer

It uses the energy stored in an ion gradient established by primary active transport.

Question 10

A solution contains 0.1 M glucose and 0.1 M NaCl. What is the total osmolarity of the solution?

Accepted Answer

$0.3 \, 	ext{Osm}$

Question 11

Which of the following would increase the rate of simple diffusion across a membrane?

Accepted Answer

Increasing the surface area of the membrane

Question 12

Which of the following best describes the process of osmosis?

Accepted Answer

The passive movement of water down its concentration gradient

Question 13

A cell is placed in a solution with 200 mOsm of impermeant solutes. Relative to the cell, the solution is:

Accepted Answer

Hypotonic

Question 14

Which of the following is an example of receptor-mediated endocytosis?

Accepted Answer

A cell internalizing cholesterol bound to LDL particles

Question 15

Which of the following best explains why facilitated diffusion of glucose can be impaired in diabetes mellitus?

Accepted Answer

Insulin-dependent glucose carriers are absent or nonfunctional, making glucose impermeant to cells.

Question 16

Which of the following is true about the electrical driving force across a membrane?

Accepted Answer

It affects only charged particles (ions).

Question 17

Which of the following best describes the difference between osmolarity and tonicity?

Accepted Answer

Osmolarity includes all solute particles; tonicity considers only impermeant solutes.

Question 18

Which of the following is a real-life example of secondary active transport?

Accepted Answer

Sodium-linked glucose transport in the intestine

Question 19

A cell is exposed to a solution with a higher concentration of impermeant solutes than its cytoplasm. What is the expected effect on the cell?

Accepted Answer

Water will leave the cell, causing it to shrink.

Question 20

Which of the following best explains why the rate of facilitated diffusion levels off at high solute concentrations?

Accepted Answer

Carrier proteins become saturated and cannot increase their rate of transport.

Cell Membrane Transport: Principles and Mechanisms

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