1. Ms. Levasseur
Biology
Plasma Membrane

2. Plasma Membrane aka – Cell membrane
Separates the interior of ALL cells from the outside environment
Protects the cell

3. What’s it made of? Lipid bilayer Embedded proteins Hydrophilic heads
Hydrophobic tails
Embedded proteins
Channels for transport

4. How does it work? Selectively Permeable
Controls movement into and out of the cell
Only allows specific molecules and ions into cell = selective = picky

5. Passive Transport No energy is needed to cross cell membrane
Spontaneous process
Molecules move from areas of higher concentration to lower concentration
3 types of passive transport
Simple diffusion
Facilitated diffusion
Osmosis

6. Simple Diffusion
The tendency of molecules to spread into an available space

7. Facilitated diffusion
Movement across membrane through special transport proteins (channels) embedded in the membrane

8. Osmosis
Diffusion of WATER across cell membrane

9. Active Transport Energy is required to move molecules across membrane
Movement against the concentration gradient – (low to high)

11. Passive and Active Transport

12. Endocytosis Exocytosis Movement of molecules INTO cell
Movement of molecules OUTSIDE of cell
Exocytosis