Quiz Chapter 3: Movement of Substances Across the Plasma Membrane

1. What is the primary difference between passive transport and active transport?

1. A. Passive transport moves substances against a concentration gradient using ATP.
2. B. Active transport requires ATP energy to move substances against a concentration gradient.
3. C. Passive transport relies exclusively on carrier proteins.
4. D. Active transport only allows the transport of water molecules.

2. Plasmolyzed plant cells can regain turgidity if placed back into distilled water. What is this recovery process called?

1. A. Hemolysis
2. B. Crenation
3. C. Deplasmolysis
4. D. Active diffusion

3. A farmer applied excessive amounts of chemical fertilizer around crop roots. Soon after, the crops wilted. What explains this?

1. A. The soil solution became hypotonic, causing root cells to burst.
2. B. The soil solution became hypertonic, drawing water out of root cells via osmosis.
3. C. Fertilizer blocked stomata, preventing transpiration.
4. D. Fertilizer caused rapid active transport of toxins into leaves.

4. Which of the following molecules moves across membranes via active transport during mineral absorption in plant roots?

1. A. Nitrate ions moving from low soil concentration into root cells
2. B. Carbon dioxide diffusing into stomata
3. C. Water entering root hair cells
4. D. Oxygen diffusing into root cells

5. During an experiment, a cylinder of potato tissue shortened and lost mass after immersion in a liquid for 2 hours. What was the liquid?

1. A. Distilled water
2. B. Hypotonic sucrose solution
3. C. Concentrated hypertonic sucrose solution
4. D. Isotonic solution

6. Which protein type undergoes a conformational structural change to transport glucose molecules down their concentration gradient?

1. A. Channel protein
2. B. Carrier protein
3. C. Glycoprotein
4. D. Peripheral protein

7. What happens to the rate of facilitated diffusion when all available transport proteins become fully saturated with solute molecules?

1. A. The rate drops to zero immediately.
2. B. The rate reaches a maximum limit (Vmax) and levels off.
3. C. The rate increases exponentially.
4. D. Active transport takes over automatically.

8. If the plasma membrane lost all its cholesterol molecules, how would its physical properties change at elevated body temperatures?

1. A. It would become overly fluid, unstable, and overly permeable.
2. B. It would become completely rigid and freeze solid.
3. C. It would prevent all water molecules from passing through.
4. D. It would automatically convert into a single cell wall layer.

9. How does salting preserve fresh fish against bacterial spoilage?

1. A. High salt levels destroy bacterial DNA directly.
2. B. High salt creates a hypertonic environment, dehydrating bacterial cells via crenation/plasmolysis.
3. C. Salt acts as an enzyme inhibitor in fish muscle tissue.
4. D. Salt increases water potential in the fish tissue.

10. Why do red blood cells burst (undergo hemolysis) in distilled water, whereas plant cells do not?

1. A. Plant cells possess a rigid cell wall made of cellulose.
2. B. Plant cells do not absorb water via osmosis.
3. C. Animal cell membranes are completely impermeable to water.
4. D. Plant vacuoles pump water out as fast as it enters.