| Define facilitated diffusion | movement of particles down a concentration gradient, from a higher to a lower concentration. |
| Is facilitated diffusion passive or active | Passive, but process involves carrier proteins and channel proteins |
| How do carrier proteins work | - first, a large molecule attaches to a carrier protein in the membrane
- then, protein changes shape
- this releases the molecules on the opposite side of the membrane |
| Define active transport | uses energy to move molecules and ions across plasma membranes against a concentration gradient. Process also includes carrier proteins. |
| Define endocytosis | - a cell surrounds a substance with a section of its plasma membrane
- the membrane then pinches off to form a vesicle inside the cell containing the ingested substance |
| Define phagocytosis | - endocytosis for solid substances
- cell membrane forms (called pseudopods) which surrounds the substance |
| Define pinocytosis | - endocytosis for liquid substances
- cell membrane forms (called pseudopods) which surrounds the substance |
| Define exocytosis | - vesicles containing substances produced by the cell pinch off from the sacs of Golgi apparatus and move towards the plasma membrane
- the vesicle fuse with the plasma membrane and release their contents outside the cell |
