1. Which properties are characteristic of ion channels? a. They are usually lipids. b. They exist on one side of the plasma membrane, usually the intracellular side. c. They can open and close depending on the presence of any of three types of "gates." d. They permit movement of ions against concentration gradients. e. They mediate facilitated diffusion. 2. Which of the following does not directly or indirectly require an energy source? a. primary active transport b. operation of the sodium/potassium pump c. the mechanism used by cells to produce a calcium ion gradient across the plasma membrane d. facilitated transport of glucose across a plasma membrane e. secondary active transport 3. If a small amount of urea were added to an işoosmotic saline solution containing cells, what would be the result? a. The cells would shrink and remain that way. b. The cells would first shrink, but then be restored to normal volume after a brief period of time. c. The cells would swell and remain that way. d. The cells would first swell, but then be restored to normal volume after a brief period of time. e. The urea would have no effect, even transiently. 4. Which is (are) true of epithelial cells? a. They can only move uncharged molecules across their surfaces. b. They may have segregated functions on luminal and basolateral surfaces. c. They cannot form tight junctions. d. They depend upon the activity of Na+/K+-ATPase pumps for much of their transport functions. e. Both b and d are correct. 5. Which is incorrect? a. Diffusion of a solute through a membrane is considerably quicker than diffusion of the same solute through a water layer of equal thickness. b. A single ion, such as K+, can diffuse through more than one type of channel. c. Lipid-soluble solutes diffuse more readily through the phospholipid bilayer of a plasma membrane than do water-soluble ones. d. The rate of facilitated diffusion of a solute is limited by the number of transporters in the membrane at any given time. e. A common example of co-transport is that of an ion and an organic molecule,

1. Which properties are characteristic of ion channels? a. They are usually lipids. b. They exist on one side of the plasma membrane, usually the intracellular side. c. They can open and close depending on the presence of any of three types of "gates." d. They permit movement of ions against concentration gradients. e. They mediate facilitated diffusion. 2. Which of the following does not directly or indirectly require an energy source? a. primary active transport b. operation of the sodium/potassium pump c. the mechanism used by cells to produce a calcium ion gradient across the plasma membrane d. facilitated transport of glucose across a plasma membrane e. secondary active transport 3. If a small amount of urea were added to an işoosmotic saline solution containing cells, what would be the result? a. The cells would shrink and remain that way. b. The cells would first shrink, but then be restored to normal volume after a brief period of time. c. The cells would swell and remain that way. d. The cells would first swell, but then be restored to normal volume after a brief period of time. e. The urea would have no effect, even transiently. 4. Which is (are) true of epithelial cells? a. They can only move uncharged molecules across their surfaces. b. They may have segregated functions on luminal and basolateral surfaces. c. They cannot form tight junctions. d. They depend upon the activity of Na+/K+-ATPase pumps for much of their transport functions. e. Both b and d are correct. 5. Which is incorrect? a. Diffusion of a solute through a membrane is considerably quicker than diffusion of the same solute through a water layer of equal thickness. b. A single ion, such as K+, can diffuse through more than one type of channel. c. Lipid-soluble solutes diffuse more readily through the phospholipid bilayer of a plasma membrane than do water-soluble ones. d. The rate of facilitated diffusion of a solute is limited by the number of transporters in the membrane at any given time. e. A common example of co-transport is that of an ion and an organic molecule,

Biology 2e

2nd Edition

ISBN:9781947172517

Author:Matthew Douglas, Jung Choi, Mary Ann Clark

Publisher:Matthew Douglas, Jung Choi, Mary Ann Clark

Chapter5: Structure And Function Of Plasma Membranes

Section: Chapter Questions

Problem 7RQ: A scientist compares the plasma membrane composition of an animal from the Mediterranean coast with...

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