Membranes

Review Items

What materials can and cannot cross membranes? Why?

diffusion

osmosis

isotonic, hypertonic, hypotonic

membrane proteins

active transport

Review Questions

1. Describe the structure of a phospholipid molecule. [answer]
2. Define these terms: hydrophobic, hydrophilic.
3. Draw a phospholipid bilayer and label the hydrophobic and hydrophilic regions. Show where proteins are located. [answer]
4. Define and describe the following: diffusion, osmosis.
5. Explain why membranes are relatively impermeable to water-soluble molecules. [answer]
6. Explain how turgor pressure is maintained in plant cells.
7. Explain what will happen to a plant cell when it is placed in each of the following kinds of solutions and explain why: isotonic, hypertonic, hypotonic.
8. Explain what will happen to a red blood cell that is placed in each of the following kinds of solutions: isotonic, hypertonic, hypotonic.
9. Describe active transport.
10. Tell whether the pumps used in active transport are carbohydrate, lipid, protein, or nucleic acid. [answer]
11. The sodium-potassium pump is an example of _______ transport. [answer]
12. Describe the operation of the sodium-potassium pump. [answer]
13. Define and describe each of the following: Endocytosis, Phagocytosis, Exocytosis
14. Name the functions of proteins in a plasma membrane. [answer]