Question 1

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

Accepted Answer

The membrane consists of a phospholipid bilayer with proteins and other molecules embedded and able to move laterally.

Question 2

A red blood cell is placed in a solution with a higher solute concentration than its cytoplasm. What will happen to the cell?

Accepted Answer

It will shrink as water leaves the cell by osmosis.

Question 3

Which of the following best defines selective permeability?

Accepted Answer

The ability of the membrane to allow some substances to cross more easily than others.

Question 4

How does cholesterol affect membrane fluidity at different temperatures?

Accepted Answer

It decreases fluidity at high temperatures and increases it at low temperatures.

Question 5

Which equation correctly represents the net movement of water during osmosis?

Accepted Answer

$\Psi_{water}$ moves from high to low $\Psi_{water}$ (water potential)

Question 6

Which process requires energy input from the cell?

Accepted Answer

Active transport

Question 7

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

Accepted Answer

The cell will gain water, become turgid, and maintain structural integrity due to the cell wall.

Question 8

Which of the following is NOT a type of endocytosis?

Accepted Answer

Exocytosis

Question 9

A cell uses a transport protein to move glucose against its concentration gradient. Which type of transport is this?

Accepted Answer

Active transport

Question 10

Which scenario best illustrates facilitated diffusion?

Accepted Answer

Glucose entering a cell through a specific membrane protein down its concentration gradient.

Question 11

Which of the following statements about passive transport is correct?

Accepted Answer

It relies on the random movement of molecules and does not require energy input.

Question 12

What is the main difference between simple diffusion and facilitated diffusion?

Accepted Answer

Facilitated diffusion uses membrane proteins to help molecules cross the membrane.

Question 13

Which of the following best describes exocytosis?

Accepted Answer

The process by which cells release substances to the outside by vesicle fusion with the plasma membrane.

Question 14

Which factor would increase the fluidity of a cell membrane?

Accepted Answer

Increasing the proportion of unsaturated fatty acids in phospholipids.

Question 15

A cell is placed in an isotonic solution. What will happen to the cell?

Accepted Answer

There will be no net movement of water; the cell will remain the same size.

Question 16

Which of the following is true about the spontaneous assembly of phospholipid bilayers?

Accepted Answer

It is driven by the hydrophilic heads interacting with water and hydrophobic tails avoiding water.

Question 17

Which equation best describes the rate of diffusion across a membrane?

Accepted Answer

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

Question 18

Which type of endocytosis involves the cell taking in specific molecules after they bind to receptors on the cell surface?

Accepted Answer

Receptor-mediated endocytosis

Question 19

Which of the following best explains why diffusion is a passive and spontaneous process?

Accepted Answer

It is driven by the random thermal motion of molecules, moving from high to low concentration.

Question 20

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

Accepted Answer

Synthesizing phospholipids for the membrane.

Membrane Structure and Function: Study Guide

Study Guide - Practice Questions