1. Notes Cells need to regulate what moves in and out of them,in order to maintain homeostasis. The cell membrane is in charge of what comes and goes. The transport of molecules across the cell membrane can be active or passive. Active transport requires energy, passive transport does not.

2. Diffusion Diffusion is the movement of molecules from an area of High concentration to an area of low concentration. Diffusion is a type of Passive transport. Substances on the outside of the cell cross the cell membrane until there are equal concentrations of that substance, both inside and outside the cell.

3. Osmosis Osmosis is the diffusion of water (passive) When the concentration of solute molecules outside of the cell are lower than inside the cell the solution (outside of the cell) is Hypotonic.(water moves into the cell) Hypo- under

4. Solutions When the concentration of solute molecules outside the cell is higher than inside the cell the solution is said to be hypertonic.(water moves out) Hyper- over When concentrations are the same, solutions are isotinic Iso- same

5. Active transport The process of using energy to bring things into the cell. Active transport includes: The Na/K pump and bulk transport Bulk transport is used when large materials are needed and the cell has to “Pac-Man” the material to bring it into the cell.

6. Bulk Transport Bulk transport includes: Pinocytosis – the movement of large amounts of liquid. Endocytosis (phagocytosis)- is the movement of large solid particles into the cell. Exocytosis- is the movement of particles out of the cell.