Question 1

Which property of phospholipids is primarily responsible for the spontaneous formation of lipid bilayers in water?

Accepted Answer

Their amphipathic nature, with hydrophilic heads and hydrophobic tails

Question 2

Order the following substances by their ability to cross a pure phospholipid bilayer from most permeable to least permeable: O$$_2$$, H$$_2O$$, glucose, Na$$^+.$$

Accepted Answer

O$$_2$$ \u003e H$$_2O$$ \u003e glucose \u003e Na$$^+$$

Question 3

A fish living in the cold Arctic waters needs to maintain membrane fluidity. Which membrane adaptation would you expect?

Accepted Answer

Increase in unsaturated fatty acids and decrease in cholesterol

Question 4

What effect does adding cholesterol to a phospholipid bilayer have on membrane permeability?

Accepted Answer

It decreases membrane permeability by increasing packing density

Question 5

Which part of a phospholipid molecule is in direct contact with water in a bilayer?

Accepted Answer

Hydrophilic head

Question 6

How does the presence of double bonds in fatty acid tails affect membrane permeability?

Accepted Answer

Double bonds create kinks, increasing membrane permeability

Question 7

Which of the following foods is primarily made of unsaturated fatty acids?

Accepted Answer

Vegetable oil

Question 8

What happens to a human red blood cell placed in a beaker of pure, distilled water?

Accepted Answer

The cell would swell and likely burst as water rushes in

Question 9

Which equation best describes the net movement of water during osmosis across a selectively permeable membrane?

Accepted Answer

$$\Delta \Psi = \Psi_{inside} - \Psi_{outside}$$, where $$\Psi is $$water potential

Question 10

Which scenario would result in the highest membrane permeability?

Accepted Answer

A bilayer with short, unsaturated hydrocarbon tails and low cholesterol

Question 11

Why do highly saturated lipids tend to be solid at room temperature?

Accepted Answer

Their straight tails allow tight packing and strong hydrophobic interactions

Question 12

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

Accepted Answer

Movement of substances down their concentration gradient without energy input

Question 13

A vesicle containing a higher concentration of solute than its surrounding solution will:

Accepted Answer

Gain water and swell

Question 14

Which factor would most likely decrease the fluidity of a cell membrane at low temperature?

Accepted Answer

Increase in saturated fatty acids

Question 15

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

Accepted Answer

Synthesizing proteins for the cell

Question 16

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

Accepted Answer

It will lose water and shrink

Question 17

Which of the following best explains why glucose crosses the phospholipid bilayer more slowly than oxygen?

Accepted Answer

Glucose is larger and more polar than oxygen

Question 18

Which of the following would most likely increase the permeability of a membrane to water?

Accepted Answer

Increasing the number of aquaporin proteins

Question 19

Which process describes the movement of molecules from an area of high concentration to an area of low concentration due to random thermal motion?

Accepted Answer

Diffusion

Membrane Structure and Properties: Study Notes for General Biology

Study Guide - Practice Questions

Study Guide - Flashcards