Question 1

Which of the following best describes the amphipathic nature of phospholipids in the plasma membrane?

Accepted Answer

They have both hydrophilic and hydrophobic regions, allowing them to form a bilayer in aqueous environments.

Question 2

A red blood cell is placed in a solution and begins to swell until it bursts. Which type of solution is the cell in, and what is the process called?

Accepted Answer

Hypotonic solution; the process is called lysing.

Question 3

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

Accepted Answer

Synthesizing proteins for export from the cell.

Question 4

Which type of cell junction is most likely to be found in tissues that experience mechanical stress, such as the skin or heart muscle?

Accepted Answer

Desmosomes

Question 5

A patient receives an intravenous (IV) solution that is hypertonic relative to their red blood cells. What is the most likely effect on the cells?

Accepted Answer

Water will leave the cells, causing them to shrink (crenate).

Question 6

Which of the following best explains why facilitated diffusion is necessary for glucose transport across the plasma membrane?

Accepted Answer

Glucose is hydrophilic and too large to pass through the lipid bilayer without a carrier protein.

Question 7

Which equation correctly represents the relationship between osmotic pressure ($$\Pi$$), solute concentration ($$C$$), the gas constant ($$R$$), and temperature ($$T) in $$Kelvin?

Accepted Answer

$$\Pi = C R T$$

Question 8

Which of the following scenarios best illustrates secondary active transport?

Accepted Answer

Sodium ions move down their concentration gradient into the cell, simultaneously bringing glucose molecules with them via a cotransporter.

Question 9

Which of the following statements about the sodium-potassium pump is correct?

Accepted Answer

It moves 3 Na$$^+$$ ions out of the cell and 2 K$$^+$$ ions into the cell for each ATP hydrolyzed.

Question 10

A cell is placed in a solution and neither swells nor shrinks. Which of the following best describes the solution?

Accepted Answer

Isotonic

Question 11

Which of the following best describes the function of tight junctions between epithelial cells lining the intestine?

Accepted Answer

They prevent leakage of digestive enzymes and fluids between cells.

Question 12

Which process is responsible for the uptake of cholesterol into cells via specific plasma membrane receptors?

Accepted Answer

Receptor-mediated endocytosis

Question 13

Which of the following is a key difference between simple diffusion and facilitated diffusion?

Accepted Answer

Facilitated diffusion requires membrane proteins, while simple diffusion does not.

Question 14

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

Accepted Answer

They facilitate the rapid movement of water molecules across the membrane.

Question 15

Which of the following is an example of exocytosis in a neuron?

Accepted Answer

Release of neurotransmitters into the synaptic cleft.

Question 16

Which of the following best explains why animal cells are more susceptible to osmotic imbalances than plant cells?

Accepted Answer

Animal cells lack a rigid cell wall to limit hydrostatic and osmotic pressures.

Question 17

Which of the following best describes the function of the glycocalyx on the plasma membrane?

Accepted Answer

It serves as a surface marker for cell recognition and adhesion.

Question 18

A white blood cell engulfs a bacterium by extending pseudopods around it and enclosing it in a vesicle. What is this process called?

Accepted Answer

Phagocytosis

Question 19

Which of the following best describes the movement of water when a selectively permeable membrane separates two solutions of different osmolarities, and the membrane is only permeable to water?

Accepted Answer

Water will move from the side with lower osmolarity to the side with higher osmolarity until equilibrium is reached.

Question 20

Which of the following is a characteristic of carrier-mediated facilitated diffusion?

Accepted Answer

It exhibits saturation, meaning there is a maximum rate of transport when all carriers are occupied.

Cell Membranes and Transport: Structure, Function, and Mechanisms

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