Question 1

Which of the following best describes the function of the plasma membrane in human cells?

Accepted Answer

It serves as a flexible outer boundary that controls what enters and leaves the cell, maintaining selective permeability.

Question 2

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

Accepted Answer

Hypertonic solution; crenation

Question 3

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

Accepted Answer

They act as enzymes, transporters, and receptors, often spanning the membrane.

Question 4

A patient receives an intravenous solution with an osmolarity of $$400\ 	ext{mOsm/L}$$, while their intracellular fluid is $$300\ 	ext{mOsm/L}. $$What will happen to their red blood cells?

Accepted Answer

Water will move out of the cells, causing them to shrink (crenate).

Question 5

Which of the following best explains why the sodium-potassium pump is considered an example of primary active transport?

Accepted Answer

It uses the energy from ATP hydrolysis to move sodium and potassium ions against their concentration gradients.

Question 6

Which of the following statements about facilitated diffusion is correct?

Accepted Answer

It uses carrier or channel proteins to move specific polar molecules down their concentration gradient.

Question 7

A cell is placed in a hypotonic solution. Which of the following best describes the movement of water and the likely outcome for the cell?

Accepted Answer

Water moves into the cell, causing it to swell and possibly burst (lyse).

Question 8

Which of the following best describes the role of the glycocalyx on the cell surface?

Accepted Answer

It serves as a specific biological marker for cell-to-cell recognition and helps the immune system distinguish self from nonself.

Question 9

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

Accepted Answer

Storing genetic information for the cell

Question 10

A nerve cell rapidly changes its membrane potential from $$-70\ 	ext{mV} to$$ $$+30\ 	ext{mV}$$ during an action potential. Which of the following best explains the initial establishment of the resting membrane potential ($$-70\ 	ext{mV}) in $$most cells?

Accepted Answer

The diffusion of K$$^+$$ ions out of the cell through leakage channels, balanced by their electrical gradient pulling them back in

Question 11

Which of the following best describes the difference between simple diffusion and facilitated diffusion?

Accepted Answer

Simple diffusion allows nonpolar, lipid-soluble substances to pass directly through the membrane, while facilitated diffusion requires carrier or channel proteins for polar or large molecules.

Question 12

Which of the following scenarios best illustrates secondary active transport?

Accepted Answer

A glucose molecule is transported into a cell along with Na$$^+$$, using the energy stored in the Na$$^+$$ gradient established by the Na$$^+/K$^+$$ pump.

Question 13

Which of the following best explains why burn patients are at risk of losing large amounts of fluids and electrolytes?

Accepted Answer

Their plasma membranes are severely damaged, allowing substances to diffuse freely in and out of cells.

Question 14

Which of the following is a correct statement about the structure of the phospholipid bilayer in the plasma membrane?

Accepted Answer

The hydrophilic phosphate heads face both the extracellular and intracellular fluids, while the hydrophobic fatty acid tails face each other in the membrane's interior.

Question 15

Which of the following best describes the function of desmosomes in tissues such as the skin?

Accepted Answer

They anchor adjacent cells together, providing mechanical strength and preventing tearing.

Question 16

A scientist observes that a certain cell type has abundant microvilli. Which of the following is the most likely function of this cell?

Accepted Answer

Absorption of nutrients

Question 17

Which of the following best describes the process of osmosis?

Accepted Answer

The movement of water molecules from areas of low solute concentration to areas of high solute concentration through a selectively permeable membrane

Question 18

Which of the following is a key difference between tight junctions and gap junctions?

Accepted Answer

Tight junctions form impermeable barriers, while gap junctions allow direct communication and passage of small molecules between cells.

Question 19

Which of the following best explains why the Na$$^+/K$^+$$ pump is essential for nerve and muscle function?

Accepted Answer

It maintains the electrochemical gradients necessary for the generation and propagation of electrical signals.

Cells: The Living Unit – Structure and Function (Anatomy & Physiology Study Notes)

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