6 Membrane Dynamics

  1. There are no channels that normally allow diffusion of calcium ions out of a cell.
  2. Hydration shells can form around neutral molecules that are polar and around ions.
  3. Solutions with a lower number of hydration shells per unit volume than the cytosol would cause cells to swell.
  4. Solutions with a lower concentration of “bound” water molecules than human cells are hypotonic to human cells.
  5. Glucose is classified as a permeating solute, but sodium and chloride are not.
  6. In receptor-mediated endocytosis, substances are not transported through a membrane carrier.
  7. If a membrane carrier actively transports Cl- ions, it would move these ions out of the cell.
  8. Sodium-potassium pumps are primary active transporters.
  9. Membrane proteins can be classified according to location and function.
    1. Receptors in the plasma membrane are embedded within the membrane.
    2. A 0.9% NaCl solution has approximately the same osmotic pressure as normal blood plasma.
    3. Membrane proteins bound to a cell membrane can be classified by location, function, and shape.
    4. Facilitated diffusion carriers do not use ATP when they transport a substance through the cell membrane.
    5. Chloride ions do not normally diffuse out of a cell.
    6. There is much less than 280 mOsm of NaCl per unit of cytosol volume.
    7. Since a 0.9% NaCl solution is isotonic to a human cell, the human cell must contain less than 0.9% NaCl.
    8. A sodium-potassium pump is made of protein and requires genetic material’s information in order to be synthesized.
    9. When a ligand-gated channel opens, any material moving through the channel will do so passively.
    10. Phospholipids form a major component of cell membrane and all membranous organelles.
    11. If a one-liter solution contains 280 mOsm of glucose and it also contains 280 mOsm of NaCl, then a red blood cell placed into this solution would experience a net loss of water.
    12. Solution M is isotonic to a red blood cell and it contains both glucose and NaCl. Therefore, we can conclude that this isotonic solution contains less than 5% glucose and less than 280 mOsm of salt/L.
    13. Proteins of voltage-gated channels can be classified according to shape (G or F) and function in the acronym TRICCS.
    14. Chloride pumps actively transport chloride ions out of the cell.
    15. A secondary active transporter relies on normal functioning of a primary active transporter in order to remain functional.
    16. All gated channels allow substances to diffuse through the plasma membrane.
    17. The glycocalyx is a coat of carbohydrate on a cell’s plasma membrane.
    18. A water-soluble substance may be actively transported through a membrane-bound carrier.
    19. Receptor-mediated endocytosis is specific, whereas phagocytosis and pinocytosis are nonspecific.
    20. Proteins of voltage-gated channels can be classified according to location (P or I) and function in the acronym CCREAM.
    21. Opening a ligand-gated channel does not require ATP; therefore, the movement of substances through this channel is passive.
    22. Chloride pumps are carriers that perform primary active transport.
    23. The saturation point is a phenomenon associated with how many particles can pass through a carrier in a certain time.
    24. It is possible for some solutes to diffuse into hypertonic solutions.
    25. Phagocytosis and pinocytosis are examples of nonspecific endocytosis.
    26. Surrounding solutions containing more hydration shells/unit volume than the cytosol of cells will cause the cells to crenate.
    27. Certain water-soluble substances pass through membrane channels passively.
    28. An acronym for classifying membrane proteins by function is CCREAM.
    29. Secondary active transport moves one substance against a gradient while moving another substance along a gradient.
    30. In primary active transport, a membrane carrier must be phosphorylated to function.
    31. Moving up a gradient is the same as moving against a gradient.
    32. Proteins within a sodium-potassium pump could be characterized by one of the letters in TRICCS studied in chapter 3.
    33. Certain water-soluble substances may pass through membrane carriers passively.
    34. Bulk transport relies on motor molecules to move vesicles along components of the cytoskeleton.
    35. Unless opposed by hydrostatic pressure, there will be a net movement of water from hypotonic into hypertonic solutions.
    36. Separating different-size particles by using a semipermeable membrane is called dialysis.
    37. A 5% glucose solution has about the same concentration of diffusible water as a solution with a total osmolarity of 280 mOsm/L.
    38. Ions movement through a membrane can be affected by a concentration gradient and an electrochemical gradient.
    39. Not all integral proteins can be classified as transmembrane.
    40. Pinocytosis is an active process that is commonly referred to as “cell drinking.”
    41. RNA polymerase does not consist of ssRNA molecules.
    42. Water movement can be influenced by osmotic pressure and hydrostatic pressure.
    43. Cells swell when their cytosol has a higher osmotic pressure than the ECF.
    44. A solution containing only glucose in a concentration of 250 mOsm /L is hypotonic to human cells.
    45. The sodium-potassium pump needs only one ATP molecule to move two ions through the plasma membrane.
    46. All transmembrane proteins are integral proteins.
    47. If 25 mL of 5% glucose is mixed with 45 mL of 0.9% NaCl, the new solution would initially be isotonic to a human cell.
    48. Betty mixes 37.6 mL of a 5% glucose solution with 54.1 mL of a 280 mOsm/L NaCl solution to yield a 91.7-mL mixed solution. If a red blood cell is placed into this solution, the cell will initially neither swell nor crenate.
    49. The process of phagocytosis transports larger materials than does pinocytosis.
    50. Saturation can refer to the chemical structure of certain fatty acids.
    51. Solutions with a higher concentration of diffusible water molecules than the cytosol cause cells to swell.
    52. Hypertonic solutions will not always experience a net gain of water from hypotonic solutions if there is a hydrostatic gradient.
    53. Osmosis is the diffusion of water from a hypoosmotic to a hyperosmotic solution through a semipermeable membrane.
    54. Just because Na/K pumps transport two different ions, we do not call them secondary active transport carriers.
    55. When the plasma membrane temperature rises, cholesterol prevents the membrane from becoming too fluid.
    56. A phagosome develops at the plasma membrane and not the Golgi complex.
    57. If 5% glucose is isotonic to a human cell, the cell will still swell shortly after being placed into a beaker containing 5% glucose.
    58. Osmotic pressure can be defined as the pressure that will prevent diffusion of water through a membrane.
    59. Hydrostatic pressure increases within a cell if there is a net movement of water into the cell.
    60. Exocytosis expels the contents of secretory vesicles from a cell.
    61. In some situations, there can be a net movement of water from a hypertonic solution into a hypotonic solution.
    62. The number of solute particles per unit of solution volume is the important factor when calculating osmotic pressure.
    63. If a ligand-gated channel opens, the ligand that caused the opening will not pass through the channel.
    64. Solution X is 2.5% glucose and 0.45% NaCl. This solution is isotonic to a human cell.
    65. Selectively permeable is the same as semipermeable and differentially permeable.
    66. Na/K pumps do not allow 3 Na+ ions to diffuse out of the cell.
    67. Clathrin is a protein associated with RME and not phagocytosis or pinocytosis.
    68. Saturation can refer to a phenomenon associated with carriers that perform either active transport or facilitated diffusion.
    69. Aquaporins are non-gated channels that allow water to diffuse through a cell membrane.
    70. Peripheral proteins do not have contact with the plasma membrane’s fatty acids.
    71. Carbohydrates in a cell membrane are usually chains of simple sugars.
    72. A surrounding salt solution with a lower osmolarity than a cell will cause the cell to gain water.
    73. Billy mixes 5 mL of an isotonic glucose solution with 20 mL of an isotonic NaCl solution to yield a 25-ml mixed solution. If you placed a red blood cell into this 25-mL solution, at first the cell would not experience a net gain or loss of water. However, the cell would eventually begin to swell as it removes glucose from this solution.
    74. Na/K pumps consist of organic material that is synthesized at ribosomes.
    75. Solutions with a higher osmotic pressure than the cytosol will cause the cell to crenate.
    76. Solute particle size is usually not considered to be important when calculating osmotic pressure of a solution.
    77. Mechanically-gated channels are the same as stretch-gated channels.
    78. Osmotic pressure increases within a cell if there is a net movement of water out of the cell.
    79. Saturation is a phenomenon related to active transport and facilitated diffusion.
    80. In facilitated diffusion, a membrane carrier changes shape without having to be phosphorylated by ATP.
    81. Not all integral membrane proteins are transmembrane proteins.
    82. Human cells do not contain approximately 280 mOsm of glucose per unit volume of cytosol.
    83. Solution B contains only glucose and pure water and is isotonic to a red blood cell. If we add just a pinch of salt to this glucose solution, the resulting glucose-salt solution would cause the red blood cell to crenate.
    84. Certain water-soluble substances may be actively transported through membrane carriers.
    85. The steepness of a solute’s concentration gradient would have a positive effect on the rate of diffusion of that solute.
    86. The size of a diffusing particle has a negative effect on the rate at which that solute particle diffuses.
    87. It is possible to have a net movement of water from a region of higher osmotic pressure into a region of lower osmotic pressure.
    88. If a human cell is surrounded by a 0.9% glucose solution, the cell will swell.
    89. A calcium pump is a transmembrane protein that actively transports Ca2+ ions out of a cell.
    90. Bulk transport does not include osmosis or dialysis.
    91. Cholesterol helps prevent a plasma membrane from becoming brittle under lower-than-normal temperatures