Question 1

Which of the following changes would most likely increase the fluidity of a cell membrane at low temperatures?

Accepted Answer

Increasing the proportion of unsaturated fatty acids in the membrane

Question 2

A red blood cell is placed in a solution and swells until it bursts. Which of the following best describes the tonicity of the solution relative to the cell cytoplasm?

Accepted Answer

The solution is hypotonic to the cytoplasm

Question 3

Which of the following best explains why ions such as $$\mathrm{Na^+}$$ and $$\mathrm{Cl^-}$$ cannot easily cross the lipid bilayer by simple diffusion?

Accepted Answer

They are surrounded by hydration shells, making them highly polar

Question 4

Which of the following statements about cholesterol in animal cell membranes is CORRECT?

Accepted Answer

Cholesterol maintains membrane fluidity at low temperatures by preventing tight packing of phospholipids

Question 5

A cell is exposed to a toxin that inhibits desaturase enzymes. What is the most likely effect on the cell membrane?

Accepted Answer

The membrane will become less fluid due to increased saturated fatty acids

Question 6

Which of the following best describes facilitated diffusion?

Accepted Answer

Movement of substances along their concentration gradient with the help of membrane proteins

Question 7

Which of the following molecules would most easily cross a pure phospholipid bilayer by simple diffusion?

Accepted Answer

Oxygen ($$\mathrm{O_2$})$$

Question 8

A scientist increases the temperature of a cell membrane. What is the expected effect on membrane fluidity and why?

Accepted Answer

Fluidity increases because phospholipids move more rapidly

Question 9

Which of the following is a function of integral (transmembrane) proteins in the cell membrane?

Accepted Answer

They serve as channels or carriers for facilitated diffusion

Question 10

Which of the following best describes the amphipathic nature of transmembrane proteins?

Accepted Answer

They have both hydrophilic and hydrophobic regions

Question 11

A vesicle containing a 0.2 M sucrose solution is placed in a beaker containing a 0.5 M sucrose solution. What will happen to the vesicle?

Accepted Answer

Water will move out of the vesicle, causing it to shrink

Question 12

Which of the following statements about simple diffusion is correct?

Accepted Answer

It is a spontaneous process with $$\Delta G \u003c 0$$

Question 13

Which of the following is NOT a function of membrane proteins?

Accepted Answer

Synthesis of phospholipids in the cytoplasm

Question 14

Which of the following would DECREASE the permeability of a cell membrane to water?

Accepted Answer

Increasing the cholesterol content

Question 15

Peripheral membrane proteins differ from integral membrane proteins in that peripheral proteins:

Accepted Answer

Are attached to the membrane surface via non-covalent interactions

Question 16

Which of the following best describes osmosis?

Accepted Answer

Movement of water molecules across a selectively permeable membrane from low to high solute concentration

Question 17

A cell membrane is composed of phospholipids with long, saturated fatty acid tails. Which of the following is a likely property of this membrane?

Accepted Answer

Low fluidity and low permeability

Question 18

Which of the following best explains why small nonpolar molecules cross the membrane more easily than large polar molecules?

Accepted Answer

Small nonpolar molecules can dissolve in the hydrophobic core of the membrane

Question 19

Which of the following is TRUE about the movement of phospholipids in the membrane?

Accepted Answer

They move laterally within the same leaflet

Question 20

Which of the following scenarios best illustrates the role of membrane proteins in facilitated diffusion?

Accepted Answer

Glucose entering a cell through a specific carrier protein

Week 5 - Oct 3

Study Guide - Practice Questions

Study Guide - Flashcards