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| 1200757289 | selective permeability | Biological membranes regulate the passage of substances. | 1 | |
| 1200757290 | amphipathic | Having both a hydrophilic and hydrophobic region. | 2 | |
| 1200757291 | fluid mosaic model | Currently accepted model of cell membrane structure in which the membrane is described as a mosaic of protein molecules drifting laterally in a fluid bilayer of phospholipids. | 3 | |
| 1200757292 | integral protein | Transmembrane protein with hydrophobic regions that extend into and often completely span the hydrophobic region of the membrane and with hydrophilic regions in contact with aqueous solution on either side of the membrane (or lining the channel in the case of a channel protein). | 4 | |
| 1200757293 | peripheral protein | Protein loosely bound to the surface of a membrane or to a part of an integral protein and not embedded in the lipid bilayer. | 5 | |
| 1200757294 | glycolipid | A lipid with covalently attached carbohydrate(s). | 6 | |
| 1200757295 | glycoprotein | A protein with covalently attached carbohydrate(s). | 7 | |
| 1200757296 | transport protein | A transmembrane protein that helps a certain substance or class of closely related substances to cross the membrane. | 8 | |
| 1200757297 | aquaporin | A channel protein in the plasma membrane of a plant, animal, or microorganism cell that specifically facilitates osmosis, the diffusion of water across the membrane. | 9 | |
| 1200757298 | diffusion | Spontaneous movement of a substance down its concentration gradient, from a region of higher concentration to lower concentration. | 10 | |
| 1200757299 | concentration gradient | A region along which the density of a chemical substance increases or decreases. | 11 | |
| 1200757300 | passive transport | The diffusion of a substance across a biological membrane with no use of energy. | 12 | |
| 1200757301 | osmosis | The diffusion of water across a selectively permeable membrane. | 13 | |
| 1200757302 | tonicity | the ability of a solution surrounding a cell to cause that cell to gain or lose water. | 14 | |
| 1200757303 | isotonic | A solution surrounding a cell that has no effect on water passage into or out of the cell (due to equal concentrations of a substance inside and outside of the cell). | 15 | |
| 1200757304 | hypertonic | A solution surround a cell that will cause it to lose water (due to a higher concentration of a solute in the solution outside of the cell). | 16 | |
| 1200757305 | hypotonic | A solution surrounding a cell that will cause it to take up water (due to a lower concentration of a solute in the solution outside of the cell). | 17 | |
| 1200757306 | osmoregulation | Regulation of solute concentrations wand water balance by a cell or organism. | 18 | |
| 1200757307 | turgid | Swollen or distended, as in plant cells. A walled cell becomes this way if it has a greater solute concentration than its surroundings, resulting in entry of water. | 19 | |
| 1200757308 | flaccid | Limp; lacking firmness, as in plant cell surroundings where there is no tendency for water to enter the cell. | 20 | |
| 1200757309 | plasmolysis | Occurs in walled cells; the cytoplasm shrivels and the plasma membrane pulls away from the cell wall; occurs when the cell loses water to a hypertonic environment. | 21 | |
| 1200757310 | facilitated diffusion | Spontaneous passage of molecules or ions across a biological membrane with the assistance of specific transmembrane transport proteins. | 22 | |
| 1200757311 | ion channel | A transmembrane protein channel that allows a specific ion to flow across the membrane down its concentration gradient. | 23 | |
| 1200757312 | gated channel | Transmembrane protein channel that opens or closes in response to a particular stimulus. | 24 | |
| 1200757313 | active transport | The movement of a substance across a cell membrane, with energy use, against its concentration or electrochemical gradient; mediated by specific transport proteins. | 25 | |
| 1200757314 | sodium-potassium pump | A transport protein in the plasma membrane of animal cells that actively transports sodium out of the cell and potassium into the cell. | 26 | |
| 1200757315 | membrane potential | Difference in electrical charge (voltage) across a cell's membrane, due to different distribution of ions. Affects the activity of excitable cells and the transmembrane movement of all charged substances. | 27 | |
| 1200757316 | electrochemical gradient | Diffusion gradient of an ion, affected by both concentration difference of the ion across a membrane and the ion's tendency to move relative to membrane potential. | 28 | |
| 1200757317 | electrogenic pump | An ion transport protein that generates voltage across a membrane. | 29 | |
| 1200757318 | proton pump | An active transport protein in a cell membrane that uses ATP to transport hydrogen ions out of a cell against their concentration gradient, generating a membrane potential in the process. | 30 | |
| 1200757320 | cotransport | The coupling of a "downhill" diffusion of one substance to the "uphill" transport of another substance against its own concentration gradient. | 31 | |
| 1200757322 | exocytosis | Cellular secretion of biological molecules by the fusion of vesicles containing them with the plasma membrane. | 32 | |
| 1200757324 | endocytosis | Cellular uptake of biological molecules and particulate matter through the formation of new vesicles from the plasma membrane. | 33 | |
| 1200757326 | phagocytosis | Type of endocytosis in which the cell takes up large particulate substances. It is carried out by some protists and by certain immune cells of animals. | 34 | |
| 1200757327 | pinocytosis | Type of endocytosis where the cell ingests extracellular fluid and its dissolved solutes . | 35 | |
| 1200757329 | receptor-mediated endocytosis | Movement of specific molecules into a cell by the inward budding of membranous vesicles containing proteins with receptor sites specific to the molecules being taken in; enables a cell to acquire bulk quantities of specific subtances. | 36 | |
| 1200757331 | ligand | A molecule that specifically binds to another molecule, usually a larger one. | 37 |
