Lecture Outline for February 2, 2005


Topic: Cell Membrane Function

Chapter 4 section 4.1

Figures used in lecture: 4.4. 4.5, 4.6, 4.7, 4.8, 4.9

Additional Resources

Transport across cell membranes including diffusion, active transport, osmosis


Key Words

passive transport, simple diffusion, facilitated diffusion, active transport


Be able to use your knowledge of cell membrane structure and function to answer this question.

Two of the symptoms of diabetes are excessive thirst and frequent urination. Why?


Membrane Functions

1. To isolate the cell's contents from the external environment.

Be able to explain how the phospholipid bilayer performs this function.

2. To regulate the passage of materials into and out of the cell.

Be able to explain how membrane proteins perform this function.

3. To communicate with other cells.

Be able to explain how membrane carbohydrates perform this function.


Transport Across Membranes

Be able to describe the features of each of the following types of movement across membranes:

1. Passive Transport

a. diffusion

1.) simple diffusion

2.) facilitated diffusion

b. osmosis

2. Active Transport