1. Which statement about membrane phospholipids is not true?
a. They associate to form bilayers.
b. They have hydrophobic "tails."
c. They have hydrophilic "heads."
d. They give the membrane fluidity.
e. They flop readily from one side of the membrane to the other.
2. Human growth hormone binds to a specific protein on the plasma membrane. This protein is called a a. ligand.
d. hydrophobic protein.
e. cell adhesion molecule.
3. Which statement about membrane proteins is not true?
a. They all extend from one side of the membrane to the other.
b. Some serve as channels for ions to cross the membrane.
c. Many are free to migrate laterally within the membrane.
d. Their position in the membrane is determined by their tertiary structure.
e. Some play roles in photosynthesis.
4. Which statement about membrane carbohydrates is not true?
a. Most are bound to proteins.
b. Some are bound to lipids.
c. They are added to proteins in the Golgi apparatus.
d. They show little diversity.
e. They are important in recognition reactions at the cell surface.
5. Which statement about animal cell junctions is not true?
a. Tight junctions are barriers to the passage of molecules between cells.
b. Desmosomes allow cells to adhere strongly to one another.
c. Gap junctions block communication between adjacent cells.
d. Connexons are made of protein.
e. The fibers associated with desmosomes are made of protein.
6. You are studying how the protein transferrin enters cells. When you examine cells that have taken up transferring, it is inside clathrin-coated vesicles. Therefore, the most likely mechanism for uptake of transferrin is a. facilitated diffusion.
b. proton antiport.
c. receptor-mediated endocytosis.
d. gap junctions.
e. ion channels.
7. 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.
8. Facilitated diffusion and active transport both a. require ATP.
b. require the use of proteins as carriers.
c. carry solutes in only one direction.
d. increase without limit as the solute concentration increases.
e. depend on the solubility of the solute in lipid.
9. Primary and secondary active transport both a. generate ATP.
b. are based on passive movement of sodium ions.
c. include the passive movement of glucose molecules.
d. use ATP directly.
e. can move solutes against their concentration gradients.
10. Which statement about osmosis is not true?
a. It obeys the laws of diffusion.
b. In animal tissues, water moves into the cell which is hypertonic to the medium.
c. Red blood cells must be kept in a plasma that is hypoosmotic to the cells.
d. Two cells with identical osmotic potentials are isosmotic to each other.
e. Solute concentration is the principal factor in osmosis.
Was this article helpful?