2. Cell Membranes (both) Thin, flexible barrier The cell membrane is a lipid bilayer. It is also semi- permeable which means that it only lets in some materials. FUNCTION: The cell membrane regulates what enters and leaves the cell and provides protection and support.

3. Cell Wall (plant only) Found only in plant and fungus cells. Provide support and protection for the cell.

4. Diffusion Concentration: the mass of solute in a given volume of solution. Diffusion: when particles move from a higher concentration to a lower concentration. When the concentration is the same throughout a system, the system is in equilibrium.

5. Osmosis Osmosis: the diffusion of water through a selectively permeable membrane.

6. Osmosis Isotonic: same concentration Hypotonic: less solute than another solution Hypertonic: more solute than another solution.

7. Effects of Osmosis on a Cell

8. Levels of Organization Unicellular: organism with only one cell Multicellular: organism made of more than one cell

9. Multicellular Organisms In multicellular organisms, cells can develop in different ways to perform specialized tasks. Levels of Organization 1.Organelles 2.Cells 3.Tissues 4.Organs 5.Organ systems 6. Organism