| A | B |
|---|
| plasma membrane | A barrier that surrounds the cell and functions in controlling what goes in and out of the cells and in the passage of chemical messages to and from the cell. |
| phospholipid bilayer | A double layer of phospholipid with hydrophillic heads and hydrophobic tails. |
| channel proteins | Forms passageways that allow particles or molecules to pass through the plasma membrane. |
| concentration gradient | A difference in concentration between one region and another region. |
| passive transport | Substance move down a concentration gradient from [high] to [low] without the use of energy. |
| secondary active transport | Movement of substance via transport proteins against a concentration gradient from [low] to [high] with the use of ATP. |
| diffusion | The net movement of molecules down a concentration gradient from [high] to [low]. Can be a solid, liquid, or gas. |
| semi permeable | Allows some molecules to pass through or permeate, but prevent other molecules from passing. |
| simple diffusion | The easy passage of substances across the phospholipid bilayer; the net movement is from high concentration to low concentration. |
| facilitated diffusion | Molecules can only diffuse across the cell membrane with the aid of channel or carrier proteins. |
| osmosis | Movement of water towards regions of higher solute concentration. |
| isotonic | The concentration of solutes is the same outside and inside the cell. |
| hypertonic | The concentration of solutes in the environment is higher than inside the cell. |
| hypotonic | The concentration of solutes in the environment is lower than inside the cell. |
| endocytosis | The plasma membrane engulfs fluid droplets or particles from outside the cell and pinches of a membranous sac called a vesicle inside the cell. |
| phagocytosis | The engulfing of large particles, including whole microorganisms by endocytosis. |
| pinocytosis | The engulfing of small particles or liquids by endocytosis. |
| exocytosis | The removal of waste materials or products a cell has made by a process that is the reverse of endocytosis. |
