Q: Which equation correctly represents osmolarity?

$$\text{Osmolarity} = \frac{\text{osmoles of solute}}{\text{liter of solution}}$$

Question 1

Which of the following best describes the relationship between homeostasis and equilibrium in the context of body fluid compartments?

Accepted Answer

Homeostasis maintains osmotic equilibrium but allows for chemical and electrical disequilibrium.

Question 2

A patient is given an intravenous solution containing 2 OsM glucose. Compared to a 1 OsM NaCl solution, the glucose solution is:

Accepted Answer

Hyperosmotic

Question 3

Which of the following statements about osmosis is correct?

Accepted Answer

Osmosis is the movement of water across a membrane in response to a solute concentration gradient.

Question 4

A red blood cell is placed in a solution and swells until it bursts. Which of the following best describes the tonicity of the solution relative to the cell?

Accepted Answer

Hypotonic

Question 5

Which equation correctly represents osmolarity?

Accepted Answer

$$	ext{Osmolarity} = \frac{	ext{osmoles of solute}}{	ext{liter of solution}}$$

Question 6

Which of the following is a property of simple diffusion across a cell membrane?

Accepted Answer

It is limited to lipophilic molecules.

Question 7

A solution is hyposmotic to a cell. What can you conclude about its tonicity?

Accepted Answer

It is always hypotonic.

Question 8

Which of the following best describes the function of the sodium-potassium pump (Na+-K+ ATPase)?

Accepted Answer

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

Question 9

Which of the following is true regarding facilitated diffusion?

Accepted Answer

It requires a membrane protein and moves molecules down their concentration gradient.

Question 10

A cell is placed in a solution containing a high concentration of nonpenetrating solutes. What will happen to the cell?

Accepted Answer

It will shrink.

Question 11

Which of the following best explains why glucose is considered a nonpenetrating solute once inside the cell?

Accepted Answer

Glucose is converted to glucose-6-phosphate, preventing its exit from the cell.

Question 12

Which of the following is NOT a property of carrier-mediated transport?

Accepted Answer

Unlimited transport rate regardless of substrate concentration

Question 13

Which of the following best describes the process of transcytosis?

Accepted Answer

Movement of molecules through the cell via a combination of endocytosis, vesicular transport, and exocytosis

Question 14

Which equation is used to calculate the equilibrium potential for a single ion?

Accepted Answer

$$E_{ion} = \frac{61}{z} \log \left( \frac{[ion]_{out}}{[ion]_{in}} \right)$$

Question 15

Which of the following would cause depolarization of a cell starting at resting membrane potential?

Accepted Answer

Sodium enters the cell

Question 16

Which of the following is a property of open (leak) channels?

Accepted Answer

They allow ions to move back and forth without regulation.

Question 17

Which of the following best describes the role of the Na+-glucose secondary active transporter (SGLT)?

Accepted Answer

It uses the sodium gradient established by the Na+-K+ ATPase to move glucose against its concentration gradient.

Question 18

Which of the following is true regarding the resting membrane potential of a typical cell?

Accepted Answer

It is established primarily by the movement of potassium ions through leak channels.

Question 19

A baby loses 1.1 lbs due to diarrhea. How much fluid should be given to compensate for this loss? (Assume 1 L water = 1 kg, 1 kg = 2.2 lbs)

Accepted Answer

500 mL

Question 20

Which of the following best describes the difference between osmolarity and tonicity?

Accepted Answer

Osmolarity can be measured; tonicity is unitless and describes the effect of a solution on cell volume.

Membrane Dynamics: Osmosis, Diffusion, and Transport Mechanisms

Study Guide - Practice Questions

Study Guide - Flashcards