$\Delta G = RT \ln \left( \frac{[C]_\text{in}}{[C]_\text{out}} \right) + zF\Delta \Psi$

Question 1

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

Accepted Answer

A dynamic structure consisting of a phospholipid bilayer with embedded proteins and carbohydrates.

Question 2

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

Accepted Answer

To stabilize membrane fluidity across temperature changes.

Question 3

A red blood cell is placed in a hypertonic solution. What will most likely happen to the cell?

Accepted Answer

It will shrink as water leaves the cell by osmosis.

Question 4

Which equation correctly represents the calculation of osmotic pressure ($\Pi$) using van't Hoff's law?

Accepted Answer

$\Pi = iMRT$

Question 5

Which of the following molecules would most easily diffuse through the phospholipid bilayer without the help of a transport protein?

Accepted Answer

Oxygen ($O_2$)

Question 6

Facilitated diffusion differs from simple diffusion in that:

Accepted Answer

Facilitated diffusion uses transport proteins to move molecules down their concentration gradient.

Question 7

Which process is responsible for the uptake of large particles, such as bacteria, by immune cells?

Accepted Answer

Phagocytosis

Question 8

A cell is placed in an isotonic solution. What will happen to the movement of water across its membrane?

Accepted Answer

Water will move equally in both directions, and there will be no net change in cell volume.

Question 9

Which of the following best explains why sodium-potassium pumps are essential for nerve cell function?

Accepted Answer

They maintain the resting membrane potential by actively transporting $Na^+$ out and $K^+$ in.

Question 10

Which of the following is a real-life consequence of water intoxication (hyponatremia) in humans?

Accepted Answer

Cells become turgid and burst due to excessive water intake.

Question 11

Which type of membrane protein is most likely to be involved in cell-cell recognition, such as in the ABO blood group system?

Accepted Answer

Glycoproteins

Question 12

Which of the following statements about active transport is correct?

Accepted Answer

Active transport requires energy, usually in the form of ATP.

Question 13

Which equation best represents the electrochemical gradient ($\Delta G$) for ion movement across a membrane?

Accepted Answer

$\Delta G = RT \ln \left( \frac{[C]_	ext{in}}{[C]_	ext{out}} ight) + zF\Delta \Psi$

Question 14

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

Accepted Answer

Synthesis of DNA

Question 15

During receptor-mediated endocytosis, what is the role of the receptor?

Accepted Answer

To bind specific molecules and trigger vesicle formation.

Question 16

Which of the following adaptations would you expect in the membrane phospholipids of bacteria living in extremely cold environments?

Accepted Answer

A higher proportion of unsaturated fatty acids to maintain membrane fluidity.

Question 17

Which process is used by cells to secrete large molecules, such as hormones, out of the cell?

Accepted Answer

Exocytosis

Question 18

A mutation causes a cell to lack functional aquaporins. What is the most likely consequence?

Accepted Answer

The cell will have impaired water transport, affecting osmoregulation.

Question 19

Which of the following best explains how viruses such as SARS-CoV-2 enter host cells?

Accepted Answer

By triggering receptor-mediated endocytosis using specific cell surface proteins.

Question 20

Which of the following statements about the permeability of the plasma membrane is correct?

Accepted Answer

The plasma membrane is selectively permeable, allowing some substances to cross more easily than others.

Membrane Structure and Function: Study Notes (Chapter 7)

Study Guide - Practice Questions