Question 1

Which of the following best explains why the plasma membrane is described as a 'fluid-mosaic' model?

Accepted Answer

Because the membrane is flexible, with proteins, lipids, and carbohydrates moving laterally within the bilayer.

Question 2

A red blood cell is placed in a hypertonic solution. What will happen to the cell, and why?

Accepted Answer

The cell will shrink because water moves out of the cell to the area of higher solute concentration.

Question 3

Which of the following molecules is amphipathic and forms the basic structure of the plasma membrane?

Accepted Answer

Phospholipid

Question 4

Which equation best describes the movement of molecules during simple diffusion?

Accepted Answer

$J = -D \frac{dC}{dx}$

Question 5

Which of the following is NOT a function of cholesterol in the plasma membrane?

Accepted Answer

Acts as a primary transport protein for glucose

Question 6

Facilitated diffusion differs from simple diffusion in that:

Accepted Answer

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

Question 7

Which of the following best describes osmosis?

Accepted Answer

The movement of water molecules across a selectively permeable membrane from an area of low solute concentration to high solute concentration.

Question 8

Which type of membrane protein is primarily responsible for cell recognition, such as distinguishing blood types?

Accepted Answer

Cell recognition proteins

Question 9

A cell uses ATP to move sodium ions out of the cell and potassium ions into the cell. This process is an example of:

Accepted Answer

Active transport

Question 10

Which of the following best describes the process of exocytosis?

Accepted Answer

The movement of large molecules out of the cell via vesicles that fuse with the plasma membrane.

Question 11

Which of the following is a correct description of receptor-mediated endocytosis?

Accepted Answer

It uses specific membrane receptors to selectively bring in particular molecules.

Question 12

Which of the following best explains why oxygen ($O_2$) and carbon dioxide ($CO_2$) can easily cross the plasma membrane?

Accepted Answer

They are small, non-polar molecules that can diffuse through the lipid bilayer.

Question 13

Which of the following is NOT a type of passive transport?

Accepted Answer

Endocytosis

Question 14

A plant cell is placed in a hypotonic solution. What is the most likely outcome?

Accepted Answer

The cell will gain water, but the cell wall prevents bursting, resulting in turgor pressure.

Question 15

Which of the following best describes the role of carbohydrates in the plasma membrane?

Accepted Answer

They increase cell specificity and help cells adhere to form tissues.

Question 16

Which of the following is a correct statement about the movement of molecules down a concentration gradient?

Accepted Answer

Molecules move from an area of higher concentration to an area of lower concentration.

Question 17

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

Accepted Answer

Synthesizing phospholipids

Question 18

Which process is used by white blood cells to engulf and destroy bacteria?

Accepted Answer

Phagocytosis

Question 19

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

Accepted Answer

They have both a hydrophilic head and hydrophobic tails.

Question 20

Which of the following is a real-life example of facilitated diffusion?

Accepted Answer

Glucose entering a muscle cell via a specific carrier protein.

Cell Membranes: Structure, Function, and Transport Mechanisms

Study Guide - Practice Questions