Question 1

Which of the following statements about lipids is TRUE?

Accepted Answer

Lipids do not dissolve in water.

Question 2

Which structural feature distinguishes saturated fatty acids from unsaturated fatty acids?

Accepted Answer

Unsaturated fatty acids contain one or more double bonds, causing kinks in the hydrocarbon chain.

Question 3

Which type of fat would you expect to be solid at room temperature?

Accepted Answer

Fats containing primarily saturated fatty acids.

Question 4

Which of the following is NOT a category of lipids?

Accepted Answer

Nucleic acids

Question 5

What makes phospholipids suitable for forming biological membranes?

Accepted Answer

They are amphipathic, with polar heads and nonpolar tails.

Question 6

If you replace saturated fatty acids with unsaturated fatty acids in a phospholipid bilayer, what happens to membrane fluidity and permeability?

Accepted Answer

Fluidity increases and permeability increases.

Question 7

Which of the following factors would DECREASE membrane fluidity?

Accepted Answer

Reduced temperature

Question 8

A patient receives a transfusion of distilled water directly into their veins. What is the most probable result?

Accepted Answer

The patient's red blood cells will swell and possibly burst because the blood has become hypotonic compared to the cells.

Question 9

At equilibrium, for a molecule that can diffuse across a lipid bilayer, which of the following is TRUE?

Accepted Answer

There is no change in the concentration of the molecule on either side of the membrane.

Question 10

Which of the following molecules would have the HIGHEST permeability through a pure phospholipid bilayer?

Accepted Answer

Carbon dioxide ($$\mathrm{CO_2$})$$

Question 11

A vesicle containing pure water is placed in a solution with a high concentration of solutes. What will happen?

Accepted Answer

Net flow of water out of the vesicle

Question 12

How do ions and other charged molecules cross cell membranes?

Accepted Answer

Through proteins embedded in the membrane.

Question 13

Which of the following best describes the 'selectivity' of an ion channel?

Accepted Answer

Permitting passage only to a specific ion.

Question 14

Which process would be used for moving glucose from a low concentration outside the cell to a high concentration inside the cell?

Accepted Answer

Active transport

Question 15

Which of the following is a correct description of the sodium-potassium pump?

Accepted Answer

It uses ATP to move sodium out of the cell and potassium into the cell against their concentration gradients.

Question 16

Which of the following is TRUE about the fluid-mosaic model of cell membranes?

Accepted Answer

Membranes consist of a phospholipid bilayer with proteins that can move laterally.

Question 17

Which of the following would INCREASE the permeability of a phospholipid bilayer to oxygen ($$\mathrm{O_2$}$$)?

Accepted Answer

Increasing the proportion of unsaturated fatty acids.

Question 18

A dialysis bag containing 0.2 M sucrose is placed in a beaker containing 0.6 M sucrose. The membrane is permeable to water but not to sucrose. What will happen?

Accepted Answer

Water will move out of the bag, causing it to shrink.

Question 19

Which of the following is a consequence of adding cholesterol to a phospholipid membrane at moderate temperatures?

Accepted Answer

Membrane fluidity decreases.

Lipids and Membranes: Structure, Function, and Biological Roles

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