Membrane Structure Review
1. (3 pts) Give 3 functions of the plasma membrane.
a. contain cell contents
b. shape and support
c. allows materials to enter and exit
2. What is meant by the term “selectively permeable”?
Allows some things to pass and not others
3. (6 pts) Label the plasma membrane (phospholipids, cholesterol, peripheral proteins, integral
proteins, cholesterol, carbohydrate chains)
4. (2 pts) The head of the phospholipid is hydro_phyllic__ and the tail of the phospholipid is
hydro_phobic__.
5. The fluid mosaic model describes the arrangement of molecules in the cell membrane.
Modified from http://www.biologyjunction.com/cellmembrane_pptq_bi.htm
Types of Membrane Transport Review
6. Simple diffusion_ requires NO energy to move things across the cell membrane.
7. With diffusion, molecules move from an area of high concentration to an area of low concentration.
8. Osmosis is the diffusion of water molecules across a cell membrane.
9. (2 pts) Passive transport does not require additional energy & moves materials from high to
concentration.
10. (2 pts) Facilitated diffusion uses transport proteins to help move materials from high to
concentrations.
low
low
11. Active transport requires additional energy to move materials.
12. Active transport uses cellular energy known as ATP.
13. Active transport moves materials AGAINST the concentration gradient or from low to
concentration.
high
14. The sodium-potassium pump is an example of active transport.
15. Moving very large particles out of the cell is called exocytosis.
16. In exocytosis, wastes are moved out of the cell in vesicles that fuse with the cell membrane.
17. Endocytosis involves moving large particles into the cell.
18. Taking in large liquid droplets is called pinocytosis or "cell drinking".
19. "Cell eating" is known as phagocytosis.
20. (6 pts) Label each beaker solution as isotonic, hypertonic, or hypotonic and draw an arrow to show the direction of
water movement by osmosis. (Solutes cannot move.)
Modified from http://www.biologyjunction.com/cellmembrane_pptq_bi.htm