Term
|
Definition
| A molecule that has both a hydrophilic region and a hydrophobic region. |
|
|
Term
|
Definition
| Molecules that constitute the inner bilayer of biological membranes, having a polar, hydrophilic head and a nonpolar, hydrophobic tail. |
|
|
Term
|
Definition
| 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. |
|
|
Term
|
Definition
| The spontaneous tendency of a substance to move down its concentration gradient from a more concentrated to a less concentrated area. |
|
|
Term
|
Definition
| The change in solute concentration per unit distance in solute |
|
|
Term
|
Definition
| The diffusion of a substance across a biological membrane |
|
|
Term
|
Definition
| the solution with a higher concentration of solutes is said to be hypertonic |
|
|
Term
|
Definition
| The solution with a lower concentration of solutes. |
|
|
Term
|
Definition
| Solutions of equal solute concentration |
|
|
Term
|
Definition
| Diffusion of water across a selectively permeable membrane is a special case of passive transport called osmosis |
|
|
Term
|
Definition
| the control of water balance |
|
|
Term
|
Definition
| A phenomenon in walled cells in which the cytoplasm shrivels and the plasma membrane pulls away from the cell wall when the cell loses water to a hypertonic environment. |
|
|
Term
|
Definition
| The spontaneous passage of molecules and ions, bound to specific carrier proteins, across a biological membrane down their concentration gradients. |
|
|
Term
|
Definition
| an electrical of chemical stimulus causes some proteins to open |
|
|
Term
|
Definition
| The movement of a substance across a biological membrane against its concentration or electrochemical gradient, with the help of energy input and specific transport proteins. |
|
|
Term
|
Definition
| A special transport protein in the plasma membrane of animal cells that transports sodium out of potassium into the cell against their concentration gradients. |
|
|
Term
|
Definition
| The charge difference between the cytoplasm and extracellular fluid in all cells, due to the differential distributions of ions. Membrane potential affects the activity of excitable cells and the transmembrane movement of all charged substances. |
|
|
Term
|
Definition
| The diffusion gradient of an ion, representing a type of potential energy that accounts for both the concentration difference for the ion across a membrane and its tendency to move relative to the membrane potential. |
|
|
Term
|
Definition
| An ion transport protein generating voltage across the membrane. |
|
|
Term
|
Definition
| An active transport mechanism in cell membranes that consumes ATP to force hydrogen ions out of a cell and, in the process, generates membrane potential. |
|
|
Term
|
Definition
| The coupling of the “downhill” diffusion of one substance to the “uphill” transport of another against its own concentration gradient. |
|
|
Term
|
Definition
| The cellular secretion of macromolecules by the fusion of vesicles with the plasma membrane. |
|
|
Term
|
Definition
| The cellular uptake of macromoles and particulate substances by localized regions of the plasma membrane that surround the substance and pinch off to form an intracellular vesicle. |
|
|
Term
|
Definition
| A type of endocytosis involving large, particulate substances. |
|
|
Term
|
Definition
| A type of endocytosis in which the cell ingests extracellular fluid and its dissolved solutes. |
|
|
Term
| Receptor-mediated endocytosis |
|
Definition
| The movement of specific molecules into a cell by the inward budding of membraneous vesicles containing proteins with receptor sites specific to the molecules being taken in; enables a cell to aquire bulk quantities of specific substances. |
|
|
