| Term | Definition |
|---|
| active transport | molecules or ions move through the plasma membrane, accumulation either inside or outside the cell; exactly opposite to the process of diffusion; both carrier proteins and an expenditure of energy (ATP) are needed to transport molecules against their concentration gradient |
| sodium-potassium pump | carrier protein that moves sodium ions (Na+) to the outside of the cell and potassium ions (K+) to the inside of the cell; active in all animals cells, but is especially associated with nerve and muscle cells; results in both a solute concentration gradient and an electrical gradient for these ions across the plasma membrane |
| exocytosis | when a vesicle fuses with the plasma membrane as secretion occurs; the membrane of the vesicle becomes a part of the plasma membrane, which is thereby enlarged |
| endocytosis | when cells take in substances by vesicle formation; a portion of the plasma membrane invaginates to envelop the substance, and then the membrane pinches off to form an intracellular vesicle (occurs in 1 of 3 ways) |
| phagocytosis | when the material taken in by endocytosis is large, such as a food particle or another cell; common in unicellular organisms such as amoebas |
| pinocytosis | occurs when vesicles form around a liquid or around very small particles; involves a significant amount of the plasma membrane because it occurs continuously |
| receptor-mediated endocytosis | a form of pinocytosis that is quite specific because it uses a receptor protein shaped in such a way that a specific molecule such as a vitamin, peptide hormone, or lipoprotein can bind to it; selective and much more effective that ordinary pinocytosis; involved in uptake and also in transfer and exchange of substances between cells |
Combine with other sets
Share on Facebook
Share on MySpace
!