Chapter 8: Membrane Structure and Function Vocabulary
AP Biology Chapter 8: Membrane Structure and Function Bold Terms(Campbell-Reece 6th Ed)
Terms in this set (33)
A property of biological membranes that allows some substances to cross more easily than others.
A molecule that has both a hydrophilic region and a hydrophobic region. ex. phospholipid.
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.
Typically transmembrane proteins with hydrophobic regions that completely span the hydrophobic interior of the membrane.
protein appendages loosely bound to the surface of the membrane and not embedded in the lipid bilayer.
a transmembrane protein that helps a certain substance or class of closely related substances to cross the membrane.
the process by which molecules move from an area of higher concentration to an area of lower concentration
the path molecules travel when an imbalance between separated molecule concentrations exists
The diffusion of a substance across a biological membrane.
In comparing two solutions, referring to the one with a greater solute concentration.
In comparing two solutions, the one with a lower solute concentration.
Having the same solute concentration as another solution.
The control of water balance in organisms living in hypertonic, hypotonic, or terrestrial environments.
Firm. Walled cells become ____ as a result of the entry of water from a hypotonic environment.
Limp. Walled cells are ____in isotonic surroundings, where there is no tendency for water to enter.
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.
The diffusion of water across a selectively permeable membrane.
The spontaneous passage of molecules and ions, bound to specific carrier proteins, across a biological membrane down their concentration gradients.
A transport protein in the plasma membrane of a plant or animal cell that specifically facilitates the diffusion of water across the membrane (osmosis).
A protein channel in a cell membrane that opens or closes in response to a particular stimulus.
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
A special transport protein in the plasma membrane of animal cells that transports sodium (Na+) out of the cell and potassium (K+)into the cell against their concentration gradients.
The charge difference between the cytoplasm and extracellular fluid in all cells, due to the differential distribution of ions. Affects the activity of excitable cells and the transmembrane movement of all charged substances.
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.
An ion transport protein generating voltage across the membrane.
An active transport mechanism in cell membranes that consumes ATP to force hydrogen ions out of a cell and, in the process, generates a membrane potential.
The coupling of the "downhill" diffusion of one substance to the "uphill" transport of another against its own concentration gradient.
the process by which a substance is released from the cell through a vesicle that transports the substance to the cell surface and then fuses with the membrane to let the substance out
The cellular uptake of macromolecules and particulate substances by localized regions of the plasma membrane that surround the substance and pinch off to form an intracellular vesicle.
A type of endocytosis involving large, particulate substances. A process in which phagocytes engulf and digest microorganisms and cellular debris (cell eating)
A type of endocytosis in which the cell ingests (gulps) extracellular fluid and its dissolved solutes. A method of active transport across the cell membrane in which the cell takes in extracellular fluids (cell drinking)
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.
A general term for any molecule that binds specifically to a receptor site of another molecule.