$$\text{Water moves from regions of low solute concentration to high solute concentration}$$

Question 1

Which of the following best explains why lipids are insoluble in water?

Accepted Answer

Lipids have a high proportion of nonpolar C—H bonds, causing hydrophobic interactions.

Question 2

A fatty acid with the formula $$C_{18}H$$_{36}$$O_2 is $$most likely:

Accepted Answer

A saturated fatty acid

Question 3

Which of the following statements about phospholipids is TRUE?

Accepted Answer

Phospholipids contain a hydrophilic head and two hydrophobic tails.

Question 4

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

Accepted Answer

Increasing the proportion of unsaturated fatty acids in the membrane

Question 5

A cell is placed in a solution and water moves into the cell, causing it to swell. Which type of solution is the cell in?

Accepted Answer

Hypotonic

Question 6

Which of the following best describes the amphipathic nature of phospholipids?

Accepted Answer

They have both hydrophilic and hydrophobic regions.

Question 7

What is the primary function of the plasma membrane in cells?

Accepted Answer

To serve as a selective barrier and facilitate chemical reactions

Question 8

Which of the following molecules would cross a phospholipid bilayer most rapidly?

Accepted Answer

Oxygen ($$O_2)$$

Question 9

Which process requires energy input from ATP to move substances across the membrane?

Accepted Answer

Active transport

Question 10

A mutation in the CFTR protein affects which type of membrane transport?

Accepted Answer

Facilitated diffusion of chloride ions

Question 11

Which of the following best describes the fluid-mosaic model of membrane structure?

Accepted Answer

Membranes are dynamic mosaics of phospholipids and proteins.

Question 12

Which of the following would decrease membrane fluidity?

Accepted Answer

Adding more cholesterol

Question 13

Which equation best represents the movement of water during osmosis?

Accepted Answer

$$	ext{Water moves from regions of low solute concentration to high solute concentration}$$

Question 14

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

Accepted Answer

Acting as enzymes to catalyze reactions

Question 15

What structural feature distinguishes steroids from other lipids?

Accepted Answer

Presence of a four-ring structure

Question 16

Which of the following statements about channel proteins is TRUE?

Accepted Answer

Channel proteins allow ions to diffuse down their electrochemical gradients.

Question 17

A cell membrane contains phospholipids with long, saturated hydrocarbon tails. What effect does this have on the membrane?

Accepted Answer

It decreases membrane permeability.

Question 18

Which of the following best describes facilitated diffusion?

Accepted Answer

Passive movement of substances across a membrane with the help of transmembrane proteins

Question 19

Which of the following is a direct result of the sodium-potassium pump ($$Na^+/K^+$$—ATPase) activity?

Accepted Answer

Establishment of an electrochemical gradient across the membrane

Question 20

Which of the following is TRUE about secondary active transport?

Accepted Answer

It uses the energy stored in electrochemical gradients to move molecules against their concentration gradient.

Lipids, Membranes, and the First Cells: Structure and Function

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