1. Why is the cell membrane so important?

2. Cell Membrane Basics Also known as the plasma membrane
Semi-permeable-only some material can get in or out
3. Has a phospholipid bilayer
inside cell
outside cell

3. Semi-Permeable Membrane
Controls what gets in or out
Needs to allow some materials — but not all — to pass through the membrane
lipid
inside cell
outside cell
salt
waste
sugar aa
H2O

4. Semi-Permeable Membrane
What gets in easily?
Lipids
Water
Why? 1. Channels are made out protein; “likes” both water and lipids

5. Semi-Permeable Membrane Movement
Movement Types:
Passive Transport- No energy required
Active Transport- Energy required (ATP)

6. Passive (No Energy) Transport
Diffusion – molecules move from a high to low concentration
Osmosis- water moves from a high to low concentration
Wants to create homeostasis!
High Low

7. Water balance is important!
Osmosis
Water balance is important!
Hydrated
Dehydrated
“Drown”

8. Hypotonic Solution: Higher concentration of fresh water outside of the cell. Cell swells and bursts.
Hypotonic Solution: Equal amount of fresh water inside and outside of cell.
Hypertonic Solution: Lower concentration of fresh water outside of the cell. Cell shrinks.

9. Two Types of Diffusion Facilitated Diffusion:
Simple Diffusion: Osmosis and Diffusion
Facilitated Diffusion:
Uses protein pump due to size of molecules

10. VS Active Transport Molecules move from low to high
Requires energy (ATP) VS

11. Active Transport Endocytosis: Engulfs/Brings in molecules
Exocytosis: Allows molecules and waste to exit a cell