Diffusion and facilitated diffusion Quiz
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5 questions, one answer each
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1. Which type of molecule crosses the phospholipid bilayer by simple diffusion most easily?
- A. Sodium ions
- B. Glucose
- C. Oxygen
- D. Amino acids
2. What feature of a carrier protein is essential to its function?
- A. It forms a permanent pore
- B. It uses ATP to pump molecules
- C. It changes shape when it binds a molecule
- D. It is found only in organelles
3. The rate of uptake of glucose becomes constant at high glucose concentrations. What is the explanation?
- A. The concentration gradient has disappeared
- B. All carrier proteins are saturated
- C. The phospholipids have stopped moving
- D. Glucose is used up
4. Which cell would absorb a substance fastest by facilitated diffusion?
- A. A cell with a smooth membrane and few carriers
- B. A cell with a folded membrane and many carriers
- C. A cell with a smooth membrane and many carriers
- D. A cell with a folded membrane and few carriers
5. Which of these does NOT affect the rate of simple diffusion?
- A. Surface area
- B. Concentration gradient
- C. Thickness of the membrane
- D. Number of carrier proteins