| A | B |
|---|
| diffusion | movement from high to low concentration |
| facilitated diffusion | needs the help of a protein but no energy used |
| concentration gradient | the difference in concentration of a substance |
| transport protein | embedded in lipid bilayer to help substances cross the membranecross |
| equilibrium | equal concentration of a substance |
| ion channel | protein through which ions can pass |
| osmosis | the diffusion of water |
| hypotonic | more free water outside of the cell |
| active transport | requires energy |
| isotonic | equal concentration of free water in and out of cell |
| exocytosis | very large substance leaves the cell |
| hypertonic | a cell in salt water |
| endocytosis | when a large molecule enters the cell by a vesicle |
| phospholipids | allows polar molecules to cross the membrane |
| ATP | needed for active transport |
