Transport in Cells Quiz
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5 questions, one answer each
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1. Which of the following best defines diffusion?
- A. The net movement of particles from a region of higher concentration to a region of lower concentration
- B. The movement of water molecules across a partially permeable membrane
- C. The active transport of dissolved substances against a concentration gradient
- D. The random movement of all particles in any direction without net change
2. A student investigates osmosis by placing plant tissue in concentrated salt solution. The tissue loses mass. Which statement correctly explains this observation?
- A. Salt ions diffuse into the plant cells, moving down their concentration gradient
- B. Water molecules diffuse out of the plant cells through the partially permeable membrane because the external solution is more concentrated
- C. Active transport removes water from the cells to balance the salt concentration
- D. The plant cells undergo plasmolysis because the internal solution becomes more concentrated than the external solution
3. Three factors affect the rate of diffusion. Which combination correctly identifies three of these factors?
- A. Concentration gradient, temperature, and surface area
- B. Concentration gradient, pH, and membrane thickness
- C. Temperature, light intensity, and surface area
- D. Osmotic potential, surface area, and respiration rate
4. Root hair cells actively transport mineral ions from the soil solution. Why is active transport necessary for this process rather than diffusion?
- A. The concentration of mineral ions is always higher in the soil solution than in the root cell sap
- B. Mineral ions are too large to diffuse across the cell membrane
- C. Mineral ions need to move against their concentration gradient from lower concentration in the soil to higher concentration in the root cell
- D. Active transport is faster than diffusion so it is more efficient for plant growth
5. A student measures the mass of a plant tissue sample before and after placing it in distilled water for 30 minutes. The tissue gains 12 g in mass. The initial mass was 50 g. Calculate the percentage change in mass.
- A. 12%
- B. 20%
- C. 24%
- D. 38%