| A | B |
|---|
| selectively permeable | some substances can cross the membrane while others cannot |
| passive transport | the movement of dissolved materials across a cell membrane without using the cell's energy |
| diffusion | the process by which molecules move from an area of high concentration to an area of low concentration |
| osmosis | the diffusion of water molecules across a selectively permeable membrane |
| active transport | the movement of materials across a membrane using cellular energy |
| facilitated diffusion | when proteins in the cell membrane form channels through which the sugars can pass |
| endocytosis | when the cell membrane changes shape and engulfs the particle |
| exocytosis | allows large particles to leave a cell |
| energy | needed for active transport |
