1. Chapter 7 – Cell Structure & Function
Section 7.3 – Cell Boundaries

2. Movement through cell boundaries:
Diffusion:
The movement of molecules from high to low concentration.

3. Osmosis:
The diffusion of WATER through a selectively permeable membrane

4. Facilitated Diffusion:
Use of a protein channel to cross through a cell membrane

5. Active Transport:
Sometimes materials need to move in opposite concentration gradients (low to high)
Requires energy
Endocytosis (into cell)
Phagocytosis (takes food in)
Pinocytosis (takes water in)
Exocytosis (out of cell)

6. Active Transport: Notice the energy (ATP) required to move molecules AGAINST the gradient!! (low to high)

7. Concentration Levels Isotonic Solution: Equilibrium
Water will move both in and out
Cell will not change shape

8. Hypertonic Solution: (Above strength)
Solution has a higher solute concentration than the cell.
Water will move out of cell
Cell will shrink
Hypotonic Solution: (Below strength)
Solution has a lower solute concentration than the cell.
Water will move into the cell
Cell will swell