Core Questions

Cell Membrane and Transport

1. Why are phospholipids ideal for making up the selectively permeable cell membrane?

A. They repel small ionsB. They react readily with water moleculesC. They form triple layers that insulate the cellD. They have a nonpolar and polar region

D. They have a nonpolar and polar region

2. A cell begins to swell when placed in an unknown solution. What can you conclude about the solution?

A. The solution is isotonicB. The solution is hypotonicC. The solution is saturatedD. The solution is hypertonic

B. The solution is hypotonic

3. The movement of molecules against the concentration gradient requires the use of energy from what molecule?

A. ATPB. mRNAC. ProteinD. Lipid

A. ATP

4. Proteins DO NOT easily pass through the phospholipid bilayer of cell membranes because

A. The membrane is made of proteinB. They contain nitrogenC. They are very large moleculesD. They cause digestion of the cell

C. They are very large molecules

5. Once a solute and solvent are evenly distributed in a solution, they will

A. Stop moving aboutB. Move back toward a concentration of the solventC. Continue to move about but with no net movement to higher concentrationD. Be totally out of equilibrium

C. Continue to move about but with no net movement to higher concentration

6. Using the above diagram and assuming K+ ions readily cross the cell membrane, which statement best describes the movement of the K+ ions.

A. Bottom to topB. Top to bottomC. Equally in both directionsD. The cell is already at equilibrium

B. Top to bottom

Use the above diagram to answer the following question:7. Which component of this plasma membrane contains a hydrophobic region and acts as the primary barrier to most foreign substances.

A. ProteinB. CholesterolC. Carbohydrate chainD. Phospholipid bilayer

D. Phospholipid bilayer

8. Which of the following terms includes all of the others

A. PinocytosisB. EndocytosisC. Active transportD. Phagocytosis

C. Active transport

9. Compare and contrast active and passive transport in terms of energy use and concentration gradient

Active Transport Passive Transport

Energy Requires energy Does not require energy

Concentration Gradient

Molecules move up/against (low high)

Molecules move down/with (high low)

10. Differentiate between diffusion and osmosis by giving an example of each.

Diffusion is the movement of molecules from an area of high concentration to an area of low concentration.EXAMPLE: food coloring spreading in a beaker of water

Osmosis is a special type of diffusion in which water is moving across a membrane in order to balance the concentration of molecules that may not pass across the membrane themselves.EXAMPLE: water entering or leaving a piece of potato submerged in aqueous solution.