Question 1

Which of the following best describes the structure of a phospholipid in the plasma membrane?

Accepted Answer

A molecule with a hydrophilic head and two hydrophobic tails

Question 2

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

Accepted Answer

To stabilize membrane structure and reduce fluidity

Question 3

A red blood cell is placed in a solution and swells until it bursts. Which term best describes the solution?

Accepted Answer

Hypotonic

Question 4

Which of the following best explains why ions such as Na+ and K+ require transport proteins to cross the plasma membrane?

Accepted Answer

They are charged and cannot pass through the hydrophobic core of the membrane

Question 5

Which of the following is true regarding the Na+/K+ ATPase pump?

Accepted Answer

It moves 3 Na+ ions out of the cell and 2 K+ ions into the cell per ATP hydrolyzed

Question 6

Which of the following best describes osmosis?

Accepted Answer

Movement of water from an area of low solute concentration to high solute concentration across a semipermeable membrane

Question 7

A solution contains 1 mM NaCl and 1 mM glucose. What is its total osmolarity?

Accepted Answer

$$3\ 	ext{mOsm}$$

Question 8

Which of the following is a characteristic of facilitated diffusion?

Accepted Answer

It is specific and can be saturated

Question 9

Which type of membrane junction would you expect to find in tissues that experience significant mechanical stress, such as cardiac muscle?

Accepted Answer

Desmosomes

Question 10

A patient with cerebral edema is given a hypertonic saline solution. What is the physiological rationale for this treatment?

Accepted Answer

To pull water out of brain cells and reduce swelling

Question 11

Which of the following best describes secondary active transport?

Accepted Answer

It uses the energy stored in an ion gradient created by primary active transport

Question 12

Which of the following is NOT a function of the glycocalyx?

Accepted Answer

Anchoring the cytoskeleton

Question 13

Which of the following best explains why the resting membrane potential of a neuron is negative?

Accepted Answer

The plasma membrane is more permeable to K+ than to Na+

Question 14

A neuron is exposed to a toxin that blocks voltage-gated Na+ channels. What is the most likely effect on the neuron?

Accepted Answer

It will be unable to generate an action potential

Question 15

Which of the following best describes the process of exocytosis?

Accepted Answer

Fusion of a vesicle with the plasma membrane to release contents outside the cell

Question 16

Which of the following is a real-life example of retrograde axonal transport in neurons?

Accepted Answer

Movement of viruses such as rabies from the axon terminal to the cell body

Question 17

Which of the following statements about tight junctions is correct?

Accepted Answer

They fuse adjacent plasma membranes to prevent passage of molecules between cells

Question 18

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

Accepted Answer

They facilitate the passive movement of water across the membrane

Question 19

A cell is placed in a solution containing 2 mM CaCl$$_2$$ and 1 mM glucose. What is the total osmolarity of the solution?

Accepted Answer

$$5\ 	ext{mOsm}$$

Question 20

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

Accepted Answer

Facilitated diffusion requires a transport protein, while simple diffusion does not

Cell Membrane Structure, Transport Mechanisms, and Neuron Anatomy: Study Notes for Anatomy & Physiology

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