Download Cell Membranes Review

Biology 11
Mrs. Garrison
LECTURE REVIEW QUESTIONS
CELL MEMBRANES
1. What is the function of the cell (plasma) membrane?
2. What is a polar molecule?
3. Water is a polar (charged) molecule. How does this impact the interactions of water with other
molecules? How does water react with non-polar molecules, such as lipids or fats? Explain how
water’s polarity results in a high surface tension and high heat capacity. What does this
mean for living organisms that are made mostly of water?
4. Water is called the “universal solvent.” What aspect of the cell membrane prevents it from being
dissolved by the water in the cytoplasm of the cell and outside the cell? What aspect of the cell
membrane allows charged (polar) molecules to pass across the membrane.
5. Describe the molecular structure of the cell membrane—be sure to discuss:
Phospholipids—both the phosphate heads and the lipid tails and how their structure is significant to
the structure and function of the cell membrane.
Membrane proteins—include the function of these proteins, as well as the location of charged and
non-charged regions of the protein in relation to the position of the protein in the membrane.
What does hydrophobic mean? Hydrophilic?
6. Name the types of proteins found in the cell membrane and give the general function of each type.
7. Explain what selectively permeable means, and how this applies to the cell membrane.
8. The cell membrane is freely permeable to (cannot regulate) three molecules. What are these
molecules? Which of these molecules has the ability to create everyday problems for our cells, due
to the membrane’s inability to regulate it?
9. Define osmosis.
10. What is a solution? Explain the relationship between the solvent and the solute. What does it
mean to say a solution is 10% salt?
11. Explain when a solution is hypotonic, isotonic and hypertonic compared to a cell in that solution.
What will happen to the cell in each of these situations?
12. Explain diffusion, facilitated diffusion and active transport. Which require cellular energy (ATP)?
Which do not? Give examples of each of these processes.
in the cell.
13. Compare and contrast the processes of exocytosis and endocytosis. Which contributes to the
surface area of cell membrane around the cell? Which subtracts from the surface area of cell
membrane around the cell?