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 within the layer.

Question 2

Which property of phospholipids is most responsible for the formation of the bilayer structure in cell membranes?

Accepted Answer

Their amphipathic nature, having both hydrophilic and hydrophobic regions.

Question 3

A scientist increases the proportion of unsaturated fatty acids in a cell membrane. What is the most likely effect on membrane fluidity at low temperatures?

Accepted Answer

Membrane fluidity will increase, preventing the membrane from solidifying as quickly.

Question 4

Which of the following is a function of membrane proteins that is directly involved in cell-cell recognition?

Accepted Answer

Glycoproteins on the cell surface act as identification tags.

Question 5

A red blood cell is placed in a solution and swells until it bursts. Which type of solution is it most likely in?

Accepted Answer

Hypotonic

Question 6

Which of the following best explains why plant cells do not burst in a hypotonic solution, while animal cells do?

Accepted Answer

Plant cells have a rigid cell wall that provides structural support and prevents bursting.

Question 7

Which of the following statements about passive transport is correct?

Accepted Answer

It involves the movement of molecules down their concentration gradient without energy input.

Question 8

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

Accepted Answer

Active transport

Question 9

Which of the following best describes the role of cholesterol in animal cell membranes?

Accepted Answer

It acts as a fluidity buffer, maintaining membrane fluidity at different temperatures.

Question 10

Which of the following is true regarding aquaporins?

Accepted Answer

They are channel proteins that facilitate the passage of water molecules across cell membranes.

Question 11

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

Accepted Answer

It will lose water and shrink.

Question 12

Which of the following best distinguishes between channel proteins and carrier proteins?

Accepted Answer

Channel proteins provide a hydrophilic tunnel for molecules to pass through, while carrier proteins change shape to move molecules across the membrane.

Question 13

Which of the following is an example of bulk transport across the plasma membrane?

Accepted Answer

Endocytosis of large particles by phagocytic cells.

Question 14

A solution has the same solute concentration as the inside of a cell. What term best describes this solution?

Accepted Answer

Isotonic

Question 15

Which of the following best describes facilitated diffusion?

Accepted Answer

Movement of molecules down their concentration gradient with the help of membrane proteins, without energy input.

Question 16

Which of the following equations best represents the process of osmosis?

Accepted Answer

$$ \Delta \Psi = \Psi_s + \Psi_p $$

Question 17

A mutation causes a cell to lack integral proteins. Which function would be most directly affected?

Accepted Answer

Transport of specific molecules across the membrane.

Question 18

Which of the following is a real-world example of selective permeability in biological membranes?

Accepted Answer

Kidney cells reabsorbing glucose but not urea from the filtrate.

Question 19

Which of the following best explains why a membrane with more saturated hydrocarbon tails is less fluid?

Accepted Answer

Saturated hydrocarbon tails pack together tightly, increasing membrane viscosity and decreasing fluidity.

Question 20

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

Accepted Answer

They are involved in cell-cell recognition by serving as identification tags.

Membrane Structure and Function: Study Notes for General Biology

Guida di studio - Domande di pratica

Study guide - Flashcard