1. Ch. 7 Transport of Ions and Small Molecules Across the Cell Membrane
Megan Goertz

2. Passive Diffusion
Gases, such as O2 & CO2, small uncharged polar molecules, urea & ethanol readily move by passive diffusion.
Very few molecules and no ions can cross a pure phospholipid bilayer at appreciable rates by passive diffusion

3. - Use energy of ATP hydrolysis
Active Transport
ATP-powered pumps
- Use energy of ATP hydrolysis

4. Facilitated Diffusion
Channel proteins transport water or specific types of ions and hydrophilic small molecules down their concentration gradient

5. Transporters (Carriers)
Uniporters
- transport a single molecule via facilitated diffusion

6. Transporters (cont’d)
Cotransporters – Antiporters & Symporters
- couple the movement of one type of ion or milecule against it’s concentration gradient

7. Thank You