BIO102 - Chapter 4
Terms in this set (58)
The collective changes in membrane potential, beginning with depolarization to threshold and ending with return to resting potential, that occur with stimulation of an excitable cell and act as the basis for neural communication.
The energy-requiring process in which a substance binds to a specific transmembrane protein, changing its conformation to allow passage of the substance through the membrane against the electrochemical gradient for that substance.
The biologically important property of a molecule having both hydrophobic and hydrophilic regions.
A single, prominent extension that emerges from the cell body and conducts outgoing impulses away from the cell body and toward the target cell(s).
Technique whereby two different types of cells (from one organism or from different species) are joined to produce one cell with one, continuous plasma membrane.
Sterol found in animal cells that can constitute up to half of the lipid in a plasma membrane, with the relative proportion in any membrane affecting its fluid behavior.
The movement of small ions across membranes.
A process that couples the movement of two solutes across a membrane, termed symport if the two solutes are moved in the same direction and antiport if the two move in opposite directions.
Fine extensions from the cell bodies of most neurons; dendrites receive incoming information from external sources, typically other neurons.
A decrease in the electrical potential difference across a membrane.
The spontaneous process in which a substance moves from an area of higher concentration to one of lower concentration, eventually reaching the same concentration in all areas.
The overall difference in electrical charge and in solute concentration that determines the ability of an electrolyte to diffuse between two compartments.
Process by which the diffusion rate of a substance is increased through interaction with a substance-specific membrane protein.
A transmembrane protein that binds a specific substance and, in so doing, changes conformation so as to facilitate diffusion of the substance down its concentration gradient.
Model presenting membranes as dynamic structures in which both lipids and associated proteins are mobile and capable of moving within the membrane to engage in interactions with other membrane molecules.
Fluorescence recovery after photobleaching (FRAP)
Technique to study movement of membrane components that consists of three steps:
(1) linking cellular components to a fluorescent dye,
(2) irreversibly bleaching (removing the visible fluorescence of) a portion of the cell,
(3) monitoring the reappearance of fluorescence (due to random movement of fluorescent-dyed components from outside of the bleached area) in the bleached portion of the cell.
Technique in which a tissue sample is first frozen and then struck with a blade that fractures the tissue block along the lines of least resistance, often resulting in a fracture line between the two leaflets of the lipid bilayer; metals are then deposited on the exposed surfaces to create a shadowed replica that is analyzed by electron microscopy.
An ion channel that can change conformation between a form open to its solute ion and one closed to the ion; such channels can be voltage gated, chemical gated, or mechanically gated depending on the nature of the process that triggers the change in conformation.
Sphingosine-based lipid molecules linked to carbohydrates, often active components of plasma membranes.
The reactions by which sugar groups are added to proteins and lipids.
Peripheral membrane proteins that are anchored to the membrane via linkage to a glycosylphosphatidylinositol molecule of the bilayer.
The polar, water-soluble region of a phospholipid that consists of a phosphate group linked to one of several small, hydrophilic molecules.
Property of one compartment having a higher solute concentration compared with that in a given compartment.
Property of one compartment having a lower solute concentration compared with that in a given compartment.
A membrane-associated protein that penetrates or spans the lipid bilayer.
A transmembranous structure (e.g., an integral protein with an aqueous pore) permeable to a specific ion or ions.
Property of one compartment having the same solute concentration compared with that in a given compartment.
Any molecule that can bind to a receptor because it has a complementary structure.
Phospholipids self-assembled into a bimolecular structure based on hydrophobic and hydrophilic interactions; biologically important as the core organization of cellular membranes.
A membrane associated protein that is located outside the bilayer but is covalently linked to a lipid molecule within the bilayer.
Microdomains within a cellular membrane that possess decreased fluidity due to the presence of cholesterol, glycolipids, and phospholipids containing longer, saturated fatty acids. A proposed residence of GPI-anchored proteins and signaling proteins.
An artificial lipid bilayer that self-assembles into a spherical vesicle or vesicles when in an aqueous environment.
The electrical potential difference across a membrane.
The lipid-rich material wrapped around most neurons in the vertebrate body.
The process through which an action potential is propagated along the membrane of a neuron by sequentially triggering action potentials in adjacent stretches of membrane.
The point of contact of a terminus of an axon with a muscle fiber, the neuromuscular junction is a site of transmission of nerve impulses from the axon across the synaptic cleft to the muscle fiber.
A chemical that is released from a presynaptic terminal and binds to the postsynaptic target cell, altering the membrane potential of the target cell.
Small chains composed of sugars covalently attached to lipids and proteins; they distinguish one type of cell from another and help mediate interactions of a cell with its surroundings.
The property of water passing through a semipermeable membrane from a region of lower solute concentration to one of higher solute concentration, with the tendency of eventually equalizing solute concentration in the two compartments.
The ratio of a solute's solubility in oil to that in water, it is a measure of the relative polarity of a biological substance.
A membrane-associated protein that is located entirely outside of the lipid bilayer and interacts with it through noncovalent bonds.
The name given to membrane phospholipids that are built on a glycerol backbone.
Phosphate-containing lipids that represent the primary constituents of the lipid bilayer of cellular membranes. Phospholipids include both phosphoglycerides and sphingomyelin.
The membrane serving as a boundary between the interior of a cell and its extracellular environment.
The shrinkage that occurs when a plant cell is placed into a hypertonic medium; its volume shrinks as the plasma membrane pulls away from the surrounding cell wall.
Any substance that can bind to a specific molecule (ligand), often leading to uptake or signal transduction.
The electrical potential difference measured for an excitable cell when it is not subject to external stimulation.
Propagation of a nerve impulse when one action potential triggers another at the adjacent stretch of unwrapped membrane (i.e., propagating by causing the action potentials to jump form one node of Ranvier to the next).
The membrane property of being freely permeable to water while allowing much slower passage to small ions and polar solutes.
The overall process in which information carried by extracellular messenger molecules is translated into changes that occur inside a cell.
Single-particle tracking (SPT)
A technique for studying movement of membrane proteins that consists of two steps: (1) linking the protein molecules to visible substances such as colloidal gold particles and (2) monitoring the movements of the individual tagged particles under the microscope.
A class of membrane lipids—derivations of sphingosine—that consist of sphingosine linked to a fatty acid by its amino group.
The specialized junction of a neuron with its target cell.
The narrow gap between two excitable cells. A presynaptic cell conducts impulses toward a synapse; a postsynaptic cell always lies on the receiving side of a synapase.
The storage sites for neurotransmitter within the terminal knobs of a neuronal axon.
The point during depolarization of an excitable cell where voltage-gated sodium channels open, with the resulting Na+ influx causing a brief reversal in membrane potential.
The temperature at which a membrane is converted from a fluid state to a crystalline gel in which lipid-molecule movement is greatly reduced.
The portion of a membrane protein that passes through the lipid bilayer, often composed of non-polar amino acids in an α-helical conformation.