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58 Cards in this Set
- Front
- Back
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active transport
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membrane protein-mediated movement of a substance across a membrane against a concentration or electrochemical gradient; a energy-requiring process
page 208 |
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anion exchange protein
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aquaporins (AQPs)
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any of a family of membrane channel proteins that facilitate the rapid movement of water molecules into or out of cells in tissues that require this capability; such as the proximal tubules of the kidneys
page 208 |
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ATP synthase
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alternative name for an F-type ATPase when it catalyzes the reverse process in which the exergonic flow of protons down their electrochemical gradient is used to drive ATP synthesis
page 211, 280, 307 |
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antiporter
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coupled transport of two solutes across a membrane in opposite directions
page 203 |
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β-barrel
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A beta barrel is a large beta-sheet that twists and coils to form a closed structure in which the first strand is hydrogen bonded to the last. Beta-strands in beta-barrels are typically arranged in an antiparallel fashion.
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alternating conformation model
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membrane transport model in which a carrier protein alternates between two conformation states, such that the solute-binding site of the protein is open or accessible first to one side of the membrane and then to the other
page 202 |
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bacteriorhodopsin
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transmembrane protein complexed with rhodopsin, capable of transporting protons across the bacterial cell membrane to create a light-dependent electrochemical proton gradient.
page 215 |
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carbonic anhydrase
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an enzyme that catalyzes the interconversion of dissolved bicarbonates and carbon dioxide.
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chloride-bicarbonate exchanger
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a phylogenetically preserved transport protein responsible for mediating the electroneutral exchange of chloride (Cl) for bicarbonate (HCO3) across a plasma membrane.
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cystic fibrosis (CF)
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a disease whose symptoms result from an inability to secrete chloride ions that is, in turn, caused by a genetic defect in a membrane protein that functions a a chloride ion channel
page 206 |
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CF transmembrane conductance regulator (CFTR)
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a membrane protein that functions as a chloride ion channel, a mutant form of which can lead to cystic fibrosis
page 206 |
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channels
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page 202, 374
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coupled transport
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The linked, simultaneous transport of two substances across a cell membrane (or another intracellular membrane). If the two substances are moving in the same direction (both into the cell or both out of the cell) it is called symport. If the two substances are moving in opposite directions (one moves into the cell while the other moves out) it is called antiport.
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channel protein
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membrane protein that forms a hydrophilic channel through which solutes can pass across the membrane without any change in the conformation of the channel protein
page 202 |
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carrier protein
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membrane protein that transports solutes across the membrane by binding to the solute on one side of the membrane and then undergoing a conformational change that transfers the solute to the other side of the membrane
page 202 |
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directionality
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having two ends that are chemically different from each other; used to describe a polymer chain such as a protein, nucleic acid, or carbohydrate; also used to describe membrane transport systems that selectively transport solutes across a membrane in one direction
page 31, 209 |
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exocytosis
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fusion of vesicle membranes with the plasma membrane so that contents of the vesicle can be expelled or secreted to the extracellular environment
page 341 |
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endocytosis
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uptake of extracellular materials by infolding of the plasma membrane, followed by pinching off of a membrane-bound vesicle containing extracellular fluid and materials
page 342 |
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electrochemical potential
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transmembrane gradient of an ion, with both an electrical component due to the charge separation quantified by the membrane potential and concentration component; also called electrochemical gradient
page 196 |
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facilitated diffusion
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membrane protein-mediated movement of a substance across a membrane that does not require energy because the ion or molecule being transported is moving don an electrochemical gradient
page 202 |
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hypertonic solution
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Hypertonic refers to a greater concentration. In biology, a hypertonic solution is one with a higher concentration of solutes on the outside of the cell. When a cell is immersed into a hypertonic solution, the tendency is for water to flow out of the cell in order to balance the concentration of the solutes.
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hypotonic solution
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Hypotonic refers to a lesser concentration. A hypotonic solution has a lower concentration of solutes than its surroundings, so in an attempt to balance concentrations, water will rush into the cell, causing swelling.
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liposomes
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a minute spherical sac of phospholipid molecules enclosing a water droplet, esp. as formed artificially to carry drugs or other substances into the tissues.
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ligand-gated channels
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an integral membrane protein that forms an ion-conducting pore that opens when a specific molecule (ligand) binds to the channel
page 372 |
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membrane transport
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the collection of mechanisms that regulate the passage of solutes such as ions and small molecules through biological membranes namely lipid bilayers that contain proteins embedded in them.
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membrane potential (Vm)
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voltage across a membrane created by ion gradients; usually the inside of a cell is negatively charged with respect to the outside
page 196, 367 |
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multidrug resistance (MDR) transport protein
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an ABC-type ATPase that uses the energy of ATP hydrolysis to pump hydrophobic drugs out of cells
page 211 |
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symporter
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coupled transport of two solutes accross a membrane in the same direction
page 203 |
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ion channels
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membrane protein that allows the passage of specific ions through the membrane; generally regulated by either changes in membrane potential (voltage-gated channels) or binding of a specific ligand (ligand-gated) channels
page 205, 372 |
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isotonic solution
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a solution having the same osmotic pressure as blood
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lumen
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internal space enclosed by a membrane, usually the endoplasmic reticulum or related membrane systems
page 89 |
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mechanosensitive channels
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Mechanosensitive channels or mechanosensitive ion channels are membrane proteins capable of responding over a wide dynamic range to external mechanical stimuli.
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Na+/glucose symporter
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Sodium-dependent glucose cotransporters are a family of glucose transporter found in the intestinal mucosa of the small intestine They contribute to renal glucose reabsorption.
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osmosis
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movement of water through a semipermeable membrane driven by a difference in solute concentration on the two sides of the membrane
page 199 |
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osmolarity
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solute concentration on one side of a membrane relative to that on the other side of the membrane; dives the osmotic movement of water across the membrane
page 200 |
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partition coefficient
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the ratio of the concentrations of a solute in two immiscible or slightly miscible liquids, or in two solids, when it is in equilibrium across the interface between them.
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plasmolysis
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outward movement of water that causes the plasma membrane to pull away from the cell wall in cells that have been exposed to a hypertonic solution
page 200 |
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porins
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transmembrane protein that forms pores for the facilitated diffusion of small hydrophilic molecules; found in the outer membranes of mitochondria, chloroplasts, and many bacteria
page 205, 244, 297 |
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pumps (active transport)
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Active transport is the movement of all types of molecules across a cell membrane against its concentration gradient (from low to high concentration).
the proteins involved in it as pumps, normally uses the chemical energy of ATP. |
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shell of hydration
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a shell of any chemical species that acts as a solvent and surrounds a solute species.
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simple diffusion
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unassisted net movement of a solute from a region where its concentration is higher to a region where its concentration is lower
page 197 |
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selective permeability
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a membrane that will allow certain molecules or ions to pass through it by diffusion and occasionally specialized "facilitated diffusion".
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transport proteins
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membrane protein that recognizes substances with great specificity and assists their movement across a membrane; includes both carrier proteins and channel proteins
page 202 |
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secretion
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a process by which substances are produced and discharged from a cell, gland, or organ for a particular function in the organism or for excretion.
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transmembrane channels
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an integral membrane protein possessing one or more hydrophobic regions that span the membrane plus hydrophilic regions that protrude from the membrane on both sides
page 177 |
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turgor pressure
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pressure that builds up in a cell due to the inward movement of water that occurs because of a higher solute concentration inside the cell than outside; accounts for the firmness, or turgidity, of fully hydrated cells or tissues of plants and other organisms
page 200 |
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voltage-gated channels
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are activated by changes in electrical potential difference near the channel; these types of ion channels are especially critical in neurons, but are common in many types of cells.
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uniporter
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membrane protein that transports a single solute from one side of a membrane to the other
page 203 |
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concentration gradient
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transmembrane gradient in concentration of a molecule or ion, expressed as a ratio of the concentration of the substance on one side of the membrane to the concentration on the other side of the membrane; the sole driving force for transport of molecules across a membrane, but only one of two components of the electrochemical potential that serves as the driving force for transport of ions across a membrane
page 196 |
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counterions
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the ion that accompanies an ionic species in order to maintain electric neutrality. In table salt the sodium cation is the counterion for the chlorine anion and vice versa.
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Na+/K+ ATPase (pump)
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an enzyme located in the plasma membrane (to be specific, an electrogenic transmembrane ATPase) in all animals. The enzyme pumps sodium out of cells, while pumping potassium into cells.
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direct active transport
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membrane transport in which the movement of solute molecules or ions across a membrane is coupled directly to an exergonic chemical reaction, most commonly the hydrolysis of ATP
page 209 |
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glucose transporter (GLUT)
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membrane carrier protein responsible for the facilitated diffusion of glucose
page 203 |
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ATPase pumps (P-type)
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Prominent examples of P-type ATPases are the sodium-potassium pump (Na+,K+-ATPase), the plasma membrane proton pump (H+-ATPase), the proton-potassium pump (H+,K+-ATPase) and the calcium pump (Ca2+-ATPase).
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ATPase pumps (F-type)
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It uses a proton gradient to drive ATP synthesis by allowing the passive flux of protons across the membrane down their electrochemical gradient and using the energy released by the transport reaction to release newly formed ATP from the active site of F-ATPase. In some bacteria, sodium ions may be used instead.
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ATPase pumps (V-type)
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V-ATPases couple the energy of ATP hydrolysis to proton transport across intracellular and plasma membranes of eukaryotic cells.
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ATPase pumps (ABC-type)
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