| A | B |
|---|
| active transport | energy-requiring process that moves material across a cell membrane against a concentration difference |
| cell membrane | thin, flexible barrier around a cell; regulates what enters and leaves the cell |
| cell wall | strong supporting layer around the cell membrane in plants, algae, and some bacteria |
| concentration | how much of a substance is in a solution |
| diffusion | process by which molecules tend to move from an area where they are more concentrated to an area where they are less concentrated |
| endocytosis | process by which a cell takes material into the cell by infolding of the cell membrane |
| equilibrium | when the concentration of a solute is the same throughout a solution |
| exocytosis | process by which a cell releases large amounts of material |
| facilitated diffusion | movement of specific molecules across cell membranes through protein channels |
| hypertonic | when comparing two solutions, the solution with the greater concentration of solutes |
| hypotonic | when comparing two solutions, the solution with the lesser concentration of solutes |
| isotonic | when the concentration of two solutions is the same |
| lipid bilayer | double-layered sheet that forms the core of nearly all cell membranes |
| osmosis | diffusion of water through a selectively permeable membrane |
| phagocytosis | process in which extensions of cytoplasm surround and engulf large particles and take them into the cell |
| pinocytosis | process by which a cell takes in liquid from the surrounding environment |
