Question 1

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

Accepted Answer

A double layer of phospholipids with proteins embedded, where both lipids and proteins can move laterally.

Question 2

A red blood cell is placed in a solution and it shrivels. Which of the following best describes the solution?

Accepted Answer

The solution is hypertonic to the cell.

Question 3

Which of the following statements about facilitated diffusion is correct?

Accepted Answer

It uses transport proteins to move molecules down their concentration gradient without energy input.

Question 4

The sodium-potassium pump is an example of which type of membrane transport?

Accepted Answer

Active transport

Question 5

Which of the following best explains why membranes rich in unsaturated fatty acids remain fluid at lower temperatures?

Accepted Answer

Unsaturated fatty acids have kinks that prevent tight packing of phospholipids.

Question 6

A plant cell is placed in a hypotonic solution. What will most likely happen to the cell?

Accepted Answer

It will gain water, become turgid, and the cell wall will prevent bursting.

Question 7

Which of the following is a function of membrane carbohydrates?

Accepted Answer

They serve as recognition sites for cell-cell interactions.

Question 8

Which process is responsible for the uptake of cholesterol into human cells?

Accepted Answer

Receptor-mediated endocytosis

Question 9

A cell is placed in a solution with a lower solute concentration than the cytoplasm. Which equation best describes the direction of water movement?

Accepted Answer

$\Delta \Psi = \Psi_{solution} - \Psi_{cell}$, water moves from solution to cell if $\Psi_{solution} > \Psi_{cell}$

Question 10

Which of the following best describes cotransport across a membrane?

Accepted Answer

The coupled transport of one solute down its gradient with another solute against its gradient.

Question 11

Which of the following is true about the sidedness of membranes?

Accepted Answer

The composition of proteins, lipids, and carbohydrates differs between the two faces of the membrane.

Question 12

A mutation causes a cell to lack functional aquaporins. Which process would be most directly affected?

Accepted Answer

Facilitated diffusion of water across the membrane

Question 13

Which of the following best explains why cholesterol is important in animal cell membranes?

Accepted Answer

It stabilizes membrane fluidity across temperature changes.

Question 14

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

Accepted Answer

Synthesis of phospholipids

Question 15

A cell is actively transporting sodium ions out and potassium ions in. Which equation represents the energy requirement for this process?

Accepted Answer

$\Delta G = \Delta G^\circ + RT \ln \left( \frac{[K^+]_{in}}{[K^+]_{out}} \cdot \frac{[Na^+]_{out}}{[Na^+]_{in}} \right)$

Question 16

Which of the following scenarios best illustrates exocytosis?

Accepted Answer

A neuron releases neurotransmitters into the synaptic cleft.

Question 17

Which of the following would most likely increase the rate of diffusion of a solute across a membrane?

Accepted Answer

Increasing the concentration gradient of the solute

Question 18

Familial hypercholesterolemia is caused by which cellular defect?

Accepted Answer

Missing or defective LDL receptor proteins

Question 19

Which of the following best describes the role of the electrochemical gradient in membrane transport?

Accepted Answer

It is the combined effect of the ion concentration gradient and the membrane potential.

Question 20

Which of the following is an example of phagocytosis?

Accepted Answer

A white blood cell engulfing a bacterium to form a food vacuole.

Membrane Structure and Function: Study Notes for General Biology

Study Guide - Practice Questions