2. Cell Boundaries 7-3

3. The beginning and the end… 1. All cells have a cell membrane –Thin –Flexible 2. Some cells have additional support known as the cell wall –Strong –Rigid

4. KEY: Cell membrane regulates, protects, and supports 1. Made of a lipid bilayer (meaning 2 layers) 2. Often described as the “Fluid Mosaic Model” 3. Contains: –Lipids (water-proof and separate) –Proteins (act as doors and anchors) –Cholesterol (rigidity) –Carbohydrates (cell markers) 4. All do a specific function in making the cell membrane selectively permeable

5. Fluid Mosaic Model

6. Cell Wall Main function is protection and support Found in plants, algae, fungi, and bacteria Made from fibers, carbs, cellulose, etc. Made inside cell and released

7. Label the Cell Membrane