1. How does the cell transport material? 9/24/07

2. Cell Membrane Regulates what enters and leaves cell
Cell membrane like a mosaic

3. Passive Transport Diffusion
Does not require cellular energy
Living cells have liquid interior and its surrounded by liquid
Diffusion is the tendency for molecules to move from high concentration to low concentration

4. Diffusion Solution is a liquid mixture of two or more substances
Solutions have equal concentrations on both sides

5. Osmosis Diffusion of water through a selectively permeable membrane
Water moves from Higher concentration to lower concentration

6. Osmosis Isotonic solutions—same strength in and out of cell
Hypotonic solution---below strength
Concentration in cell is greater than out
Hypertonic solution—above strength
Concentration out of cell is greater than inside cell

7. Osmotic Pressure
Osmosis exerts a pressure on the hypertonic side of a selectively permeable membrane
Cell is filled with salts, sugars, proteins, and other molecules

8. Facilitated Diffusion
Doesn’t use cell energy
Uses protein channel to help molecules diffuse across the selectively permeable membrane
Needs concentration difference

9. Active Transport Requires cell energy
Moves substances from low concentration to high concentration
Example Na and K pump
Low concentration Na in cell High concentration K inside cell
Pumps Na out and K inside

10. Active Transport
Endocytosis—taking material into cell by means of infoldings or pockets of cell membrane
Also called phagocytosis
Exocytosis is the removal of large amounts of material outside the cell

11. Diversity of Cellular Life
Unicellular organisms
Grow
Respond to the environment and reproduce just like multicellular
Examples
Bacteria
Some algae

12. Diversity of Cellular Life
Multicellular Organisms
Cells rely on one another or interdependent
Cell specialization
Particular function within the organism

13. Levels of Organization
Individual Cells
Tissues
Organs
Organ Systems

14. www.cellsalive.com cell model