1. The cell membrane is a phospholipid bilayer. Sometimes you will hear it referred to as a “fluid mosaic”.

2. Because these lipids have a hydrophobic end, they form a barrier between the outside and inside of the cell.

3. Passive transport through the membrane involves diffusion or osmosis

4. Active transport requires the cell to use energy

5. Facilitated Diffusion Requires some energy from the cell Proteins in the membrane help move ions or molecules across the membrane

6. Active Transport: Facilitated Diffusion

7. Other forms of active transport Exocytosis – Exo = outside – The cell sends OUT a package of substances Endocytosis – Endo = inside – The cell engulfs and brings IN substances

8. Endocytosis and exocytosis are another form of active transport