Osmosis Quiz
Questions: 16 · 10 minutes
1. An animal cell is transferred from an isotonic solution to distilled water. Assuming its membrane is intact, what change is most likely?
It shrinks because water follows solute out of the cell
It swells as water enters and may eventually burst
It remains unchanged because distilled water contains no particles
It builds a rigid cell wall to resist incoming water
2. Two otherwise identical osmosis experiments begin with the same concentration gradient, but one is kept moderately warmer without damaging the membrane. What is the most likely effect?
The direction of net water movement reverses
Osmosis stops because warm water cannot cross membranes
The initial movement of water is generally faster because molecules have more kinetic energy
The initial rate remains exactly the same because temperature affects only solutes
3. A dialysis bag contains a concentrated sucrose solution and is placed in distilled water. The bag allows water through but not sucrose. What should happen over time?
The bag should lose mass because sucrose draws water outward
The bag should lose sucrose until its contents become distilled water
The bag should maintain exactly the same mass because sucrose cannot cross
The bag should gain mass because water moves into it
4. Potato strips become limp after being left in concentrated salt water. Which explanation best fits this observation?
Salt breaks down the potato cell walls, so water can no longer exist inside
Water moves out of the cells because the surrounding solution has a higher effective solute concentration
Salt enters the cells and actively pumps water into their vacuoles
Water and salt stop moving because concentrated solutions prevent diffusion
5. What feature of a membrane is essential for osmosis to produce a lasting concentration difference?
It must allow water to cross more readily than at least some relevant solutes
It must block both water and all dissolved particles completely
It must use ATP to pump water against its concentration gradient
It must be equally permeable to water and every dissolved substance
6. A plant cell is placed in concentrated salt solution, and its plasma membrane pulls away from the cell wall. What is this process called?
Cytolysis
Plasmolysis
Deplasmolysis
Active transport
7. In an isotonic environment, what is happening to water at a cell membrane?
No water molecules cross the membrane
Water enters the cell but cannot leave
Water leaves the cell but cannot enter
Water crosses in both directions at equal overall rates, producing no net movement
8. What is osmotic pressure?
The external pressure required to prevent net water movement by osmosis into a solution
The pressure exerted only by a plant cell wall after a cell loses water
The force used by membrane pumps to move solutes using ATP
The atmospheric pressure needed to make a membrane permeable to solutes
9. Two sides of a U-tube contain equal concentrations of the same nonpenetrating solute and are separated by a membrane permeable only to water. What net change should occur?
The solute should cross until all particles collect on one side
Water should move permanently toward the left side
Water should move permanently toward the right side
There should be no net movement of water, although water molecules continue crossing both ways
10. Side A contains 2% sugar and side B contains 10% sugar. A membrane between them permits only water to pass. What is the expected net direction of water movement?
There is not enough information because water cannot cross membranes without ATP
From side B to side A
Equally in both directions with no initial net movement
From side A to side B
11. What is the main role of aquaporins in cell membranes?
They convert water into ions that can cross the lipid bilayer
They form channels that increase the rate at which water crosses the membrane
They prevent all water movement when a concentration gradient exists
They actively pump dissolved salts out of cells
12. Equal volumes of ideal 0.5 M glucose and 0.5 M sodium chloride solutions are separated by a membrane permeable only to water. Assuming sodium chloride dissociates fully, what is expected?
Water moves toward the sodium chloride side because it contains more dissolved particles
There is no net movement because both solutions have the same molarity
Water moves toward the glucose side because glucose molecules are larger
Sodium and chloride ions cross the membrane toward the glucose side
13. Which statement best defines osmosis?
The transport of dissolved solutes through a membrane by carrier proteins
The movement of any particles from lower concentration to higher concentration using cellular energy
The net movement of water across a selectively permeable membrane toward the side with a higher effective solute concentration
The movement of water caused only by gravity or external stirring
14. A red blood cell is placed in a solution with a higher concentration of nonpenetrating solutes than the cell interior. What is the most likely result?
Solutes leave the cell, causing it to burst
Water enters until the cell becomes turgid
Water leaves the cell, causing it to shrink
Water stops moving across the membrane in either direction
15. A healthy plant cell is placed in a hypotonic solution. What usually happens?
Its cell wall dissolves as solute enters
It loses water and undergoes plasmolysis
It gains water and becomes turgid as the cell wall limits expansion
It bursts immediately because it has no structural support
16. How does osmosis differ from diffusion in its broader sense?
Osmosis specifically describes net water movement across a selectively permeable membrane
Diffusion applies only to gases, whereas osmosis applies only to liquids
Osmosis always requires energy, whereas diffusion never occurs in living cells
Diffusion requires a membrane, whereas osmosis occurs without one