Question 1

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

Accepted Answer

A dynamic bilayer of amphipathic phospholipids with proteins and carbohydrates embedded or attached, allowing lateral movement.

Question 2

Which of the following changes would most likely increase the fluidity of a cell membrane at low temperatures?

Accepted Answer

Decreasing the amount of cholesterol in the membrane.

Question 3

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

Accepted Answer

It will gain water and burst (lyse).

Question 4

Which of the following molecules can most easily diffuse across a pure phospholipid bilayer without the help of a protein?

Accepted Answer

Oxygen ($$O_2)$$

Question 5

Which of the following best explains why facilitated diffusion does not require energy?

Accepted Answer

Molecules move down their concentration gradient with the help of transport proteins.

Question 6

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

Accepted Answer

Active transport

Question 7

Which of the following statements about membrane carbohydrates is correct?

Accepted Answer

They are involved in cell-cell recognition and are found only on the extracellular surface.

Question 8

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

Accepted Answer

The cell will undergo plasmolysis as the membrane pulls away from the cell wall.

Question 9

Which of the following is a function of integral membrane proteins?

Accepted Answer

Facilitating the passage of specific molecules across the membrane.

Question 10

Which process is responsible for the uptake of cholesterol into animal cells via specific receptor proteins?

Accepted Answer

Receptor-mediated endocytosis

Question 11

Which equation best represents the movement of water during osmosis?

Accepted Answer

$$Water: [Low\ solute] \rightarrow [High\ solute]$$

Question 12

Which of the following best describes cotransport in plant cells?

Accepted Answer

The movement of sucrose into the cell is coupled with the movement of $$H^+$$ ions down their gradient.

Question 13

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

Accepted Answer

Synthesis of DNA

Question 14

Which type of cell signaling involves hormones traveling through the circulatory system to reach target cells?

Accepted Answer

Endocrine signaling

Question 15

What is the main role of an electrogenic pump in animal cells?

Accepted Answer

To generate voltage across the membrane by moving ions against their gradients.

Question 16

Which of the following best describes the sequence of events in cell signaling?

Accepted Answer

Reception → Transduction → Response

Question 17

Which of the following is true about ligand-gated ion channel receptors?

Accepted Answer

They open in response to the binding of a specific ligand, allowing ions to pass through.

Question 18

Which of the following best explains why glucose requires a carrier protein to cross the plasma membrane?

Accepted Answer

Glucose is a large, polar molecule that cannot easily diffuse through the hydrophobic core.

Question 19

Which of the following is a real-life example of phagocytosis?

Accepted Answer

A white blood cell engulfing a bacterium.

Question 20

Which of the following best describes the effect of cholesterol on membrane fluidity at moderate temperatures?

Accepted Answer

Cholesterol decreases membrane fluidity by restraining phospholipid movement.

Membrane Transport and Cell Signaling: Structure, Function, and Mechanisms

Study Guide - Practice Questions