5 Written questions
5 Matching questions
- If a red blood cell is placed in a salt solution and bursts, what is the tonicity of the solution relative to the interior of the cell?
- What property of dishwashing liquid (detergent) makes it useful to wash grease from pans?
a) Hydrophobic nature
c) Amphipathic nature
d) Solubility in water
- True or false? The water-soluble portion of a phospholipid is the polar head, which generally consists of a glycerol molecule linked to a phosphate group.
- Which of the following statements is true about the net movement of an ion across a membrane by passive diffusion through a membrane channel?
a) The charge on the other side of the membrane is generally the opposite of the ion's charge.
b) There is a higher concentration of ions on the side of the membrane toward which the ion diffuses.
c) For every ion that diffuses through the membrane, a different ion diffuses in the opposite direction.
d) The cell expends energy as the ion passes through the membrane.
- A semipermeable membrane is placed between the following solutions. Which solution will increase in volume?
a) Solution C: 9% (m/v) NaCl
b) Solution D: 12.4% (m/v) NaCl
- a b) Solution D: 12.4% (m/v) NaCl (The water molecules actually move in both directions, but they move to a greater extent toward Solution D because it has a higher solute concentration than Solution C. This net movement of water molecules causes Solution D to increase in volume and Solution C to decrease in volume.)
- b True (The hydrophilic, or water-loving, portion of a phospholipid is the polar head, whereas the hydrophobic portion is the nonpolar tail.)
- c a) Hypotonic (The salt concentration in the solution is lower than it is in the cell, so water enters the cell, causing it to burst.)
- d c) Amphipathic nature
- e a) The charge on the other side of the membrane is generally the opposite of the ion's charge.
(Ions tend to move toward regions of unlike charge.)
5 Multiple choice questions
- c) Membrane proteins help move molecules across the membrane.
- b) The polarity of membrane phospholipids
- d) Among the three types, only pumps can concentrate substances on one side of the membrane.
(Only pumps use energy (from ATP) to move substances against electrochemical gradients.)
- a) Active transport
(Under these conditions, lactose moves against its concentration gradient, so its transport will require energy.)
- c) It will move out of the vesicles.
5 True/False questions
True or false? Osmosis is a type of diffusion. → True (Osmosis is the diffusion of water across a selectively permeable membrane.)
What name is given to the process by which water crosses a selectively permeable membrane?
e) passive transport → a) osmosis (Osmosis is the passive transport of water.)
True or false? During active transport through the sodium-potassium pump, ATP hydrolysis provides the energy to pump three sodium ions into the cell for every two potassium ions pumped out of the cell. → False
How can a lipid be distinguished from a sugar?
a) Lipids are mostly nonpolar.
b) Lipids are mostly saturated.
c) A lipid dissolves in water.
d) A lipid is made up of only hydrocarbons. → a) Lipids are mostly nonpolar.
True or false? Active transport differs from passive transport in that active transport does not require an input of energy. → False
(The sodium-potassium pump maintains a state in which the concentration of sodium is low inside the cell relative to the outside and the concentration of potassium is high inside the cell relative to the outside; thus, three sodium ions are pumped out of the cell and two potassium ions are pumped into the cell against the electrochemical gradient.)