Diffusion Quiz
Studying this course? Keep your progress in one place.
Pick an answer for each. Quizzes never use energy.
5 questions, one answer each
Each answer is checked as you go, with why.
See all 5 questions
1. What is the source of energy that drives diffusion of molecules across a cell membrane?
- A. The kinetic energy from random movement of molecules and ions
- B. Energy released from ATP hydrolysis in the cell
- C. Energy from active transport pumps in the membrane
- D. Potential energy stored in chemical bonds
2. Which statement correctly describes the direction of net movement in diffusion?
- A. Particles always move from lower concentration to higher concentration
- B. Particles move randomly in all directions, but there is a net movement from higher to lower concentration
- C. Particles move only in one direction along the concentration gradient
- D. Particles move down a concentration gradient only when the cell membrane is actively pumping them
3. Oxygen diffuses from the alveoli in the lungs into the blood. Which factor would NOT increase the rate of this diffusion?
- A. An increase in temperature
- B. An increase in the surface area of the alveolar membrane
- C. A decrease in the concentration of oxygen in the blood
- D. An increase in the thickness of the alveolar membrane
4. A plant cell is placed in a concentrated sugar solution. Water diffuses out of the cell. Which description explains why this occurs?
- A. Water molecules are moving from a region of higher water concentration inside the cell to a region of lower water concentration in the solution
- B. The cell membrane actively pumps water out of the cell using energy
- C. Sugar molecules in the solution pull water molecules out through osmosis
- D. The temperature change causes water to evaporate from the cell
5. A student investigates how temperature affects the diffusion of potassium permanganate crystals through agar jelly. At 20°C, the colour spreads 15 mm in 30 minutes. At 40°C, the colour spreads 30 mm in 30 minutes. Which statement best explains these results and identifies a limitation of this experiment?
- A. The results show diffusion is faster at higher temperatures due to greater kinetic energy, and the experiment properly controls all variables
- B. The results show diffusion is faster at higher temperatures due to greater kinetic energy, but the experiment does not isolate temperature as the only variable affecting diffusion rate
- C. The higher temperature caused the agar jelly to melt, which is why diffusion appeared faster, making this an invalid experiment
- D. The results contradict the definition of diffusion because diffusion should be unaffected by temperature