Question 1

Which of the following best describes the primary structure of the plasma membrane?

Accepted Answer

A phospholipid bilayer with embedded proteins and cholesterol

Question 2

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

Accepted Answer

To increase the strength and rigidity of the membrane

Question 3

Which type of embedded protein is responsible for transmitting signals from the extracellular environment to the inside of the cell?

Accepted Answer

Receptor protein

Question 4

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

Accepted Answer

It will shrink because water moves out of the cell

Question 5

Which of the following molecules can most easily diffuse through the lipid bilayer of the plasma membrane?

Accepted Answer

Oxygen ($$O_2)$$

Question 6

Facilitated diffusion differs from simple diffusion in that facilitated diffusion:

Accepted Answer

Requires a membrane protein to transport molecules

Question 7

Which process is responsible for the uptake of large molecules, such as insulin, into the cell?

Accepted Answer

Endocytosis

Question 8

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

Accepted Answer

Active transport

Question 9

Which of the following best explains why water moves into a cell placed in a hypotonic solution?

Accepted Answer

Water moves toward the area of higher solute concentration inside the cell

Question 10

Which of the following statements about glycoproteins in the plasma membrane is correct?

Accepted Answer

They play a key role in cell-to-cell recognition and communication

Question 11

A cell needs to export a large quantity of a hormone it has synthesized. Which process will it most likely use?

Accepted Answer

Exocytosis

Question 12

Which of the following best describes the movement of sodium ions ($$Na^+) $$through a gated channel?

Accepted Answer

Passive transport that occurs only when the channel is open

Question 13

If a cell is placed in an isotonic solution, what will happen to the cell's volume?

Accepted Answer

It will remain the same

Question 14

Which of the following is a key difference between passive and active transport across the plasma membrane?

Accepted Answer

Active transport requires energy, while passive transport does not

Question 15

A patient receives an intravenous solution that is hypotonic relative to their red blood cells. What is the most likely outcome?

Accepted Answer

Red blood cells will swell and may burst due to water gain

Question 16

Which of the following best describes the role of transport proteins in the plasma membrane?

Accepted Answer

They change shape to move specific molecules across the membrane

Question 17

Which process is most directly responsible for the removal of metabolic waste products, such as carbon dioxide, from cells?

Accepted Answer

Simple diffusion through the lipid bilayer

Question 18

A scientist observes that a certain molecule cannot cross the plasma membrane unless it binds to a specific protein, which then changes shape to move the molecule across. Which transport mechanism is being observed?

Accepted Answer

Facilitated diffusion

Question 19

Which of the following scenarios best illustrates the concept of selective permeability of the plasma membrane?

Accepted Answer

Only small, non-polar molecules can pass directly through the lipid bilayer

Question 20

Which of the following equations best represents the movement of water during osmosis?

Accepted Answer

$$H_2O$$ moves from an area of low solute concentration to high solute concentration

Plasma Membrane Structure and Transport Mechanisms

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