1. Core Questions Cell Membrane and Transport

2. 1. Why are phospholipids ideal for making up the selectively permeable cell membrane? A. They repel small ions B. They react readily with water molecules C. They form triple layers that insulate the cell D. They have a nonpolar and polar region

4. 2. A cell begins to swell when placed in an unknown solution. What can you conclude about the solution? A. The solution is isotonic B. The solution is hypotonic C. The solution is saturated D. The solution is hypertonic

5. B. The solution is hypotonic

6. 3. The movement of molecules against the concentration gradient requires the use of energy from what molecule? A. ATP B. mRNA C. Protein D. Lipid

7. A. ATP

8. 4. Proteins DO NOT easily pass through the phospholipid bilayer of cell membranes because A. The membrane is made of protein B. They contain nitrogen C. They are very large molecules D. They cause digestion of the cell

9. C. They are very large molecules

10. 5. Once a solute and solvent are evenly distributed in a solution, they will A. Stop moving about B. Move back toward a concentration of the solvent C. Continue to move about but with no net movement to higher concentration D. Be totally out of equilibrium

11. C. Continue to move about but with no net movement to higher concentration

12. 6. Using the above diagram and assuming K + ions readily cross the cell membrane, which statement best describes the movement of the K + ions. A. Bottom to top B. Top to bottom C. Equally in both directions D. The cell is already at equilibrium

13. B. Top to bottom

14. Use the above diagram to answer the following question: 7. Which component of this plasma membrane contains a hydrophobic region and acts as the primary barrier to most foreign substances. A. Protein B. Cholesterol C. Carbohydrate chain D. Phospholipid bilayer

16. 8. Which of the following terms includes all of the others A. Pinocytosis B. Endocytosis C. Active transport D. Phagocytosis

17. C. Active transport

18. 9. Compare and contrast active and passive transport in terms of energy use and concentration gradient

19. Active TransportPassive Transport EnergyRequires energyDoes not require energy Concentration Gradient Molecules move up/against (low  high) Molecules move down/with (high  low)

20. 10. Differentiate between diffusion and osmosis by giving an example of each.

21. Diffusion is the movement of molecules from an area of high concentration to an area of low concentration. EXAMPLE: food coloring spreading in a beaker of water Osmosis is a special type of diffusion in which water is moving across a membrane in order to balance the concentration of molecules that may not pass across the membrane themselves. EXAMPLE: water entering or leaving a piece of potato submerged in aqueous solution.