| A | B |
|---|
| Lipid bilayer | double layered sheet that makes up cell membranes |
| Concentration | the mass of solute in a given volume of solution |
| Diffusion | the tendancy for molecules to move from areas where they are more concentrated to less concentrated areas |
| Selective permeability | allows only certain substances to pass through |
| Osmosis | the diffusion of water across a selectively permeable membrane |
| Facilitated diffusion | the process in which proteins help diffusion across the cell membrane |
| Active transport | process by which cells use energy to move materials from areas of low concentration to higher concentration |
| Endocytosis | active transport which involves taking substances into the cell by means of infoldings of cell membrane |
| Phagocytosis | taking large particles into the cell by endocytosis |
| Exocytosis | the removal of large amounts of material from the cell |
| cell specialization | cells in multicellular organisms perform specific functions |
| tissue | a group of similar cells that perform a particular function |
| organ | many groups of tissues working together |
| organ system | a group of organs that work together to perform a specific function |
