Question 1

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

Accepted Answer

A dynamic structure where lipids, proteins, and carbohydrates can move laterally within the membrane.

Question 2

Which property of phospholipids is most responsible for the formation of the bilayer in biological membranes?

Accepted Answer

Their amphipathic nature, having both hydrophilic and hydrophobic regions.

Question 3

A cell is placed in a hypertonic solution. What is the most likely outcome for an animal cell?

Accepted Answer

The cell will lose water and shrink, a process called crenation.

Question 4

Which of the following factors would increase membrane fluidity?

Accepted Answer

Increasing the proportion of unsaturated fatty acids in the membrane.

Question 5

What is the primary function of the Na	extsuperscript{+}/K	extsuperscript{+} pump in animal cells?

Accepted Answer

To export sodium ions and import potassium ions against their concentration gradients using ATP.

Question 6

Which equation best represents the movement of water during osmosis?

Accepted Answer

Water moves from an area of low solute concentration to high solute concentration.

Question 7

Which type of membrane protein is most likely to be involved in cell signaling and recognition?

Accepted Answer

Transmembrane proteins.

Question 8

A researcher observes that a cell membrane becomes less fluid at low temperatures. Which molecule could the cell increase to counteract this effect?

Accepted Answer

Cholesterol

Question 9

Which of the following is true about facilitated diffusion?

Accepted Answer

It uses transport proteins to move molecules down their concentration gradient.

Question 10

Which of the following best describes the role of cholesterol in membrane fluidity?

Accepted Answer

Cholesterol stabilizes membrane fluidity, making membranes less fluid at high temperatures and more fluid at low temperatures.

Question 11

Which of the following transport mechanisms is correctly matched with its energy requirement?

Accepted Answer

Active transport – requires ATP

Question 12

A plant cell is placed in a hypotonic solution. What prevents the cell from bursting?

Accepted Answer

The cell wall generates osmotic pressure that stops the net flow of water.

Question 13

Which of the following is NOT a factor that affects the ability of solutes to pass through a lipid bilayer?

Accepted Answer

Color

Question 14

Which category of transporter binds two or more different types of ions or molecules and transports them in opposite directions?

Accepted Answer

Antiporter

Question 15

Which of the following equations correctly represents the hydrolysis of ATP during active transport?

Accepted Answer

$$\mathrm{ATP} \rightarrow \mathrm{ADP} + \mathrm{P_i}$$

Question 16

Which of the following statements about membrane gradients is correct?

Accepted Answer

Membrane gradients help maintain a constant internal environment distinct from the external environment.

Question 17

Which of the following is a property of peripheral membrane proteins?

Accepted Answer

They are non-covalently bound to other proteins or lipids on the membrane surface.

Question 18

Which of the following best explains why shorter phospholipid tails increase membrane fluidity?

Accepted Answer

Shorter tails interact less with each other, reducing van der Waals forces.

Question 19

Which of the following is true about channels and transporters?

Accepted Answer

Transporters undergo conformational changes to move solutes across the membrane.

Question 20

Which of the following is an example of secondary active transport?

Accepted Answer

H	extsuperscript{+}/sucrose symporter using a pre-existing H	extsuperscript{+} gradient to transport sucrose against its gradient.

Membrane Structure, Synthesis, and Transport (Chapter 5) – Study Notes

Study Guide - Practice Questions