Ch. 7 Key Concepts: - Cellular membranes are fluid mosaics of lipids and proteins. - Membrane structure results in selective permeability. - Passive transport is diffusion of a substance across a membrane with no energy investment. - Active transport uses energy to move solutes against their gradients. - Bulk transport across the plasma membrane occurs by exocytosis.
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| 2778261955 | selective permeability | A property of biological membranes that regulates which substances can pass through, allowing some and blocking others | 0 | |
| 2778261956 | amphipathic | A molecule that has both a hydrophilic region and a hydrophobic region. | 1 | |
| 2778298966 | fluid mosaic model | The currently accepted model of cell membrane structure, which envisions the membrane as a mosaic of individually inserted protein molecules drifting laterally in a fluid bilayer of phospholipids. | 2 | |
| 2778299518 | integral proteins | Typically transmembrane proteins with hydrophobic regions that completely span the hydrophobic interior of the membrane. | 3 | |
| 2778299519 | peripheral proteins | are not embedded in the lipid bilayer at all. Instead, the are loosely bound to the surface of the protein, often connected to integral proteins | 4 | |
| 2778300246 | glycolipids | Membrane carbohydrates that are covalently bonded to lipids. | 5 | |
| 2778300550 | glycoproteins | Membrane carbohydrates that are covalently bonded to proteins. | 6 | |
| 2778300658 | transport proteins | a protein that plays a role in the active or passive movement of specific substances through cell membranes | 7 | |
| 2778300659 | aquaporins | A transport protein in the plasma membrane of a plant or animal cell that specifically facilitates the diffusion of water across the membrane | 8 | |
| 2778300793 | diffusion | Movement of solutes from an area of higher concentration to an area of lower concentration to reach equilibrium | 9 | |
| 2778300794 | concentration gradient | a region along which the density of a chemical substance increases or decreases | 10 | |
| 2778301339 | passive transport | Movement of substances through a cell membrane without the use of cellular energy; includes diffusion, osmosis, and facilitated diffusion. | 11 | |
| 2778301340 | osmosis | Diffusion of water through a selectively permeable membrane | 12 | |
| 2778301417 | tonicity | The ability of a solution to cause a cell to gain or lose water; depends partly on concentration of nonpenetrating solutes relative to inside of cell. | 13 | |
| 2778301418 | isotonic | When the concentration of two solutions is the same | 14 | |
| 2778301715 | hypertonic | Having a higher concentration of solute than another solution. | 15 | |
| 2778301716 | hypotonic | Having a lower concentration of solute than another solution | 16 | |
| 2778302482 | osmoregulation | The control of water balance in organisms living in hypertonic, hypotonic, or terrestrial environments. | 17 | |
| 2778302483 | turgid | A cell with a cell wall that has a reasonable amount of pressure, making it swollen | 18 | |
| 2778302484 | flaccid | A cell with a cell wall that has a low amount of pressure, making it limp | 19 | |
| 2778302661 | plasmolysis | This happens when a cell shrinks inside its cell wall while the cell wall remains intact. | 20 | |
| 2778302662 | facilitated diffusion | A process in which substances are transported across a plasma membrane with the concentration gradient with the aid of carrier (transport) proteins; does not require the use of energy. | 21 | |
| 2778302957 | ion channels | pores in the cell membrane that allow the flow of ions to the cell | 22 | |
| 2778302958 | gated channels | A protein channel in a cell membrane that opens or closes in response to a particular stimulus. | 23 | |
| 2778303052 | active transport | The movement of particles from an area of low concentration to an area of high concentration that uses energy provided by ATP or a difference in electrical charges across a cell membrane. | 24 | |
| 2778303053 | 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. | 25 | |
| 2778303394 | membrane potential | A measurable difference in electrical charge between the cytoplasm (negative ions) and extracellular fluid (positive ions) | 26 | |
| 2778303395 | electrochemical gradient | The diffusion gradient of an ion, representing a type of potential energy that accounts for both the concentration difference of the ion across a membrane and its tendency to move relative to the membrane potential. | 27 | |
| 2778303604 | electrogenic pump | A transport protein that generates voltage across a membrane, causing a net separation in charge. | 28 | |
| 2778303605 | proton pump | An electrogenic pump that works largely with H+ ions. | 29 | |
| 2778305234 | cotransport | coupling of the "downhill" diffusion of one substance to the "uphill" transport of another against its own concentration gradient | 30 | |
| 2778305318 | exocytosis | a process by which the contents of a cell vacuole are released to the exterior through fusion of the vacuole membrane with the cell membrane. | 31 | |
| 2778305319 | endocytosis | The process by which a cell membrane surrounds a particle and encloses the particle in a vesicle to bring the particle into the cell | 32 | |
| 2778305597 | phagocytosis | A type of endocytosis in which a cell engulfs large particles or whole cells | 33 | |
| 2778305598 | pinocytosis | A type of endocytosis in which the cell ingests extracellular fluid and its dissolved solutes. | 34 | |
| 2778306007 | receptor-mediated endocytosis | The 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 substances. | 35 | |
| 2778306008 | ligands | A molecule that binds specifically to a receptor site of another molecule. | 36 |
