Lipids/membranes Multiple Choice Questions:

1. Substances move through biological membranes against concentration gradients via
A.simple osmosis. transport.
C.reverse osmosis.
D.a and b
E.None of the above

2. When placed in water, wilted plants lose their limpness because of transport of salts from the water into the plant. transport of salts into the water from the plant.
C.osmosis of water into the plant cells.
D.osmosis of water from the plant cells.
E.diffusion of water from the plant cells.

3. The compounds in biological membranes that form a barrier to the movement of materials across the membrane are
A.integral membrane proteins.
D.nucleic acids.
E.peripheral membrane proteins.

4. The interior of the phospholipid bilayer is

5. In biological membranes, the phospholipids are arranged in a
A.bilayer with the fatty acids pointing toward each other.
B.bilayer with the fatty acids facing outward.
C.single layer with the fatty acids facing the interior of the cell.
D.single layer with the phosphorus-containing region facing the interior of the cell.
E.bilayer with the phosphorus groups in the interior of the membrane.

6. When a mouse cell and a human cell are fused, the membrane proteins of the two cells become uniformly distributed over the surface of the hybrid cell. This occurs because
A.many proteins can move around within the bilayer.
B.all proteins are anchored within the membrane.
C.proteins are asymmetrically distributed within the membrane.
D.all proteins in the plasma membrane are peripheral.
E.different membranes contain different proteins.

7. You fill a shallow pan with water and place a drop of red ink in one end of the pan and a drop of green ink in the other end. Which of the following is true at equilibrium?
A.The red ink is uniformly distributed in one half of the pan, and the green ink is uniformly distributed in the other half of the pan.
B.The red and green inks are both uniformly distributed throughout the pan.
C.Each ink is moving down its concentration gradient.
D.The concentration of each ink is higher at one end of the pan than at the other end.
E.No predictions can be made without knowing the molecular weights of the pigment molecules.

8. For cells where carbon dioxide crosses the plasma membrane by simple diffusion, what determines the rate at which carbon dioxide enters the cell?
A.The concentration of carbon dioxide on each side of the membrane
B.The amount of ATP being produced by the cell
C.The amount of carrier protein in the membrane
D.The amount of energy available
E.The concentration of hydrogen ions on each side of the membrane

9. When a red blood cell is placed in an isotonic solution, which of the following will occur?
A.The cell will shrivel.
B.The cell will swell and burst.
C.The cell will shrivel, and then return to normal.
D.The cell will swell, and then return to normal.

10. The plasma membrane of animals contains carbohydrates
A.on the side of the membrane facing the cytosol.
B.on the side of the membrane facing away from the cell.
C.on both sides of the membrane.
D.on neither side of the membrane.
E.within the membrane.

11. Osmosis is a specific form of
B.facilitated transport. transport.
D.secondary active transport.
E.movement of water by carrier proteins.

12. Which of the following statements regarding osmosis is not true?
A.Osmosis refers to the movement of water along a concentration gradient.
B.In osmosis, water moves to equalize solute concentrations on either side of the membrane.
C.If osmosis occurs across a membrane, then diffusion is not occurring.
D.The movement of water across a membrane can affect the turgor pressure of some cells.

13. Starch, a polymer of glucose, remains inside plant cells because it
A.easily crosses the chloroplast and plasma membranes. a protein and so is a component of the membrane. too large to diffuse across the plasma membrane. complexed with proteins.
E.lacks the energy for active transport.

14. Which statement about membrane channels is not true?
A.They are pores in the membrane.
B.They are proteins.
C.All ions pass through the same type.
D.Movement through them is from high concentration to low.
E.Movement through them is by simple diffusion.

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