Created by
Terms in this set (144)
Chemical disequilibrium means:there are different chemicals in the intracellular fluid versus interstitial fluid versus plasma__________ is the most abundant intracellular ion, followed by _____________K+, proteins________ is the most abundant extracellular ion, followed by ____________Na+, Cl+ and HClO3-Proteins aren't abundant in ____________________. Why?interstitial fluid, they aren't needed there and are too big to cross pores from the blood plasmaProteins are abundant in the __________________ of the extracellular compartment. Why?blood plasma, cells make and secrete proteins to be sent elsewhere via the bloodChemical disequilibrium, but osmotic equilibrium- why?chemical disequilibrium is needed for electrochemical gradients used by transporters, osmotic equilibrium preserves cell shape/integrityWhy are the two ECF compartments similar? What is the exception?There is no way to really maintain disequilibrium because pores allow "leakage" of ions across the thin blood vessels, the exception is proteins because they are too big to leak throughCell membranes are _____________ barriersselectiveWhat determines whether or not membrane transport requires the use of energy?electrochemical gradient (concentration gradient and electrical gradient)What determines whether or not membrane transport requires the use of an integral protein?chemical properties like size and polarity____________: no energy required, ________ the concentration gradient. Includes _____________ and ________________.passive transport, down, simple diffusion, facilitated diffusion_____________: does not require carrier, molecules pass through cell membranesimple diffusion_______________: requires carrierfacilitated diffusion_________________: requires energy, at least one compound transported ___________ the concentration gradient. Includes ___________, _______________, and _________________.active transport, up, primary, secondary, vesicular_________________: requires direct input of energyprimary active transport_____________________: couples transport of a compound uphill with downhill transport of Na+; indirect input of energysecondary active transportSecondary active transport can either be ______________ or ________________cotransport, countertransportVesicular transport can either be _______________, ________________, or _________________endocytosis, exocytosis, phagocytosisWhat molecules go through simple diffusion?small, hydrophobic, nonpolar molecules like O2, N2, and CO2 and larger molecules like fatty acids and steroid hormonesWhat molecules go through facilitated diffusion?large, polar, hydrophilic molecules like glucose and amino acidsWhat molecules go through protein channels (passive)?polar, charged molecules like water and ionsFor active transport, __________________ aren't as important as the _________________chemical properties, concentration gradientWhat is diffusion?the movement of molecules from one location to another as a result of their random thermal motion; across a membrane from high to low concentrationNet flux of high concentration to low concentration is called _______________________ and occurs during __________________________moving down concentration gradient, diffusionIn diffusion, molecules never _______________ but there is no ________________ once equilibrium concentration is reachedstop moving, net movementDiffusion is a __________________ and moves from ________________passive process, high to lowIn diffusion, there is net movement until _____________________equilibriumDiffusion is rapid _________________________over short distancesIn diffusion, _______________ move _______________________permeable molecules, directly through membraneWhat factors affect the rate of diffusion?size, shape and lipid solubility of the molecule, thickness and composition of membrane, temperature, concentration gradient, distanceWhat implications does statement "diffusion is rapid over short distances" have for multicellularity?we cannot afford to depend on simple diffusion of O2 and CO2 from environment to all cells, so the circulatory system creates a network of blood vessels in close contact with cells to supply O2 and CO2 via fast simple diffusionThe ___________ the distance, the less likely diffusion will occcurlargerSmall and hydrophobic molecules (CO2, O2, N2, steroid hormones) = __________________ permeablehighlyLarge and hydrophilic molecules (H2O, ethanol, glycerol, amino acids, glucose, nucleosides) = ________________ permeablebarelyCharged molecules (ions) = ____________ permeablenotHow would membrane fluidity affect membrane permeability?Why is this selectivity extremely important?So how do essential molecules like glucose enter the cell?______________________= water channels (protein embedded in phospholipid bilayer)aquaporins_______________ movement of water, using aquaporins, across a membrane in response to a non-penetrating solute concentration gradientosmosisOsmosis is the movement from ___________________ to ___________________low concentration of solute, high concentration of solute___________________ is the pressure that must be applied to oppose osmosisosmotic pressureOsmosis is _______________ transportpassive_________________ is concerned with which solutes can pass through the membrane (penetrating vs. non-penetrating)tonicity____________________= more solutes outside the cellhypertonic solutionIn a hypertonic solute, water ____________ and cell _________________moves out, shrinks__________________= same solute concentration inside and outside of cellisotonic solutionIn an isotonic solution, water ____________ and cell ____________doesn't move, stays same_____________________= more solutes inside the cellhypotonic solutionIn a hypotonic solution, water ______________ and cell ________________moves in, swells_______________ are a hydrophilic "pore" through the membranechannel proteinsChannel proteins have ____________ transport and __________________________fast, open or gated channelsChannel proteins create a ________________water-filled pore_____________________ open and close in response to signalsgated channels____________________ or pores are usually openopen channelsThe difference between channels and carriers is ____________________size of moleculeGated channels allow __________________selective permeabilityKidney cells use ________________ to control how much water is reabsorbedchannelsThe types of membrane gating are __________________, ____________________, _____________________, and _____________________voltage gated, ligand-gated extracellular ligand, ligand-gated intracellular ligand, mechanically gatedVoltage gated channels depend on _________________ (____________) and examples of cells that use this mechanism are _____________________charge, electrical, excitable cellsLigand-gated channels depend on _______________________ or __________________ (____________________________)intracellular ligand, extracellular ligand, chemicalMechanically gated channels depend on _______________________ and an example of a cell that uses this mechanism is _____________________mechanical vibrations or pressure, smooth muscle cellsTypes of membrane gating- can perform facilitated diffusion- what about active transport?no, it is always passive because they don't have a mechanism to push against a concentration gradientFacilitated diffusion: movement across plasma membrane using a _______________: a ___________________ for molecules that cannot cross the plasma membrane themselvestransport protein, carrierFacilitated diffusion is still ____________, _____________ the concentration gradientpassive, downIn facilitated diffusion, there is movement until ___________________ and then what?equilibrium, once equilibrated, glucose for example now needs active transport to push against its concentration gradientWhen glucose is in low intracellular concentration, it crosses via:GLUT4 and comes in passivelyIntracellular glucose is usually ___________ because _______________________________________low, as soon as it comes into the cell it is either used to converted to glycogen for storageHow do transport proteins work?the structure of a carrier protein has two different conformations and the binding of a certain molecule will change the conformation__________________ never form an open channel between the two sides of the membranecarrier proteinsHow do carrier proteins contrast to channels?structure, speed, stimulusWhat are the three types of carrier proteins?uniport, symport, antiport_________________ transport only one kind of substrateuniport carriers___________________ move two or more substrates in the same direction across the membranesymport carriers__________________ move substrates in opposite directionsantiport carriers_________________ and _____________ are cotransporterssymport carriers, antiport carriersCarrier proteins take __________ time than channel proteinsmoreStimulus for carrier proteins is ________________________binding_____________________ is characteristic of both channels and carrier proteinssaturationAny _________________________ can be saturatedprotein-mediated transportSaturation is:a function of how much solute is outside the cellWhat is the relationship of saturation for simple diffusion?doesn't saturate- increasing concentrations of solute increases the flux into the cell- a positive relationshipWhat is the relationship of saturation for protein-mediated transport?maximal flux= plateau because there aren't an infinite number of protein carriersCells can control _________ by how many carrier proteins they expressfluxCarrier proteins can perform ________________ and _________________facilitated diffusion, active transportProtein-mediated transport reaches _______________saturationSaturation is graphed with _____________________ on x-axis and ____________________ on y-axisextracellular solute concentration, flux into cell______________________ uses energy to move molecules _______________________________active transport, against an electrochemical gradientActive transporters are often called ______________pumpsActive transporters can use two types of ____________________energy sourcesPrimary active transport uses _______________________________ as energy sourcedirect use of ATPSecondary active transport uses _______________________________________________ as energy sourceuse of an electrochemical gradient across a membrane to drive the processIt is never possible for ________________________________ molecules to have active transportsmall/medium nonpolar moleculesVesicular transport is also _______________, but it is only used for ______________________active transport, really big moleculesWhat is the main example of primary active transport?Na+/K+ ATPase______________________ is found in every cellNa+/K+ ATPaseNa+/K+ ATPase maintains ____________________________ and ____________________________, which is essential to generate the ________________________________________________________________________. It is also important for __________________________________________.high intracellular K+, high extracellular Na+, Na+ gradient across the cell membrane that is used by most secondary active transporters, chemical and electrical disequilibrium- helps establish and maintain the membrane potential of the cellNa+/K+ ATPase is ________________: moving both ions against the concentration gradient. ________________ ions OUT and ____________ ions INactive transport, 3 Na+, 2K+Na+/K+ ATPase is in every cell, but used a lot in ____________________excitable cellsNa+/K+ ATPase maintains a ________________ environment in the ECFpositiveMechanism of Na+/K+ ATPase:1. 3 Na+ from ICF bind to high-affinity sites
2. ATPase is phosphorylated using ATP and protein changes conformation
3. Na+ binding sites lose their affinity for Na+ and release 3 Na+ into ECF. High-affinity binding sites for K+ appear
4. 2K+ from ECF bind to high-affinity sites
5. Pi is released, protein changes conformation, K+ binding sites lose their affinity for K+ and release 2K+ into ICF, high-affinity binding sites for Na+ appearIn the Na+/K+ ATPase mechanism, the high-affinity sites ____________ for the ions on the side of the membrane where they are in low concenrationscavengeEnergy for Na+/K+ ATPase is ________________________________hydrolysis of ATP phosphorylates protein carrierIn Na+/K+ ATPase, phosphorylation is important for __________________________protein conformation change_______________________: ouabain, digitalin- inhibit conversion of E2-P into E1cardiac glycosidesIn ___________, inhibition of Na+/K+ ATPase is sometimes used to force the heart to pump harder due to increased need to flush out Ca+ because Na+ pump is altering Na+/Ca+ pump activitycardiac muscle cellsA common example of secondary active transport is the ______________________________Na+/glucose transporter (SGLT)___________________________= potential energy in secondary active transportconcentration gradient of Na+In the Na+/glucose transporter (SGLT), movement of ________ down gradient drives movement of glucose ____________- gradientNa+, againstWhat is the mechanism of Na+/glucose transporter (SGLT)?1. Na+ binds to carrier in lumen of intestine or kidney
2. Na+ binding creates a high-affinity site for glucose
3. Glucose binding changes carrier conformation so that binding sites now face the ICF
4. Na+ is released into cytosol, where concentration of Na+ is low. Release changes glucose-binding site to low affinity. Glucose is releasedWhat are the two sites of Na+/glucose transporter (SGLT) and why?in intestines to scavenge all glucose without wasting, in kidneys to reabsorb glucose if accidentally filtered outNa+/glucose transporter (SGLT) takes Na+ and glucose in the _____________same directionWhich type of transporter can perform secondary active transport?mostly symport, sometimes antiport, NEVER uniportTransporters maintain _______________ internal environmentsspecificChemical disequilibrium= ____________________________functional specificationWhich type of transport and carriers does Na+/glucose symporter have?secondary active transport, symportWhich type of transport and carriers does GLUT have?passive transport, facilitated diffuction, uniportWhich type of transport and carriers does Na+/K+ ATPase have?primary active transport, antiportIs glucose movement across the basolateral membrane active or passive? Explainpassive because glucose is moving down its concentration gradientWhy doesn't Na+ movement at the apical membrane require ATP?because Na+ is moving down its concentration gradient (and just bringing glucose along)Of these three processes (GLUT, Na+-glucose symporter, Na+-K+-ATPase) which one is required for the other two to work?Na+/K+ ATPaseGlucose uptake by intestinal epithelial cells: _____________ (Na+ coupled). Glucose is ______________ taken up from gut. Glucose is _____________ released for use by other tissues.secondary active transport, actively, passivelyNa+ gradient: ___________________ by Na+/K+ pumpprimary active transportVesicular transport-why is this necessary?to transport big things like some neurotransmitters, hormones, etc.What are the three types of vesicular transport?exocytosis, endocytosis, phagocytosis___________________________= sending something outside the cellexocytosis_____________________= bringing something into the cellendocytosisNeurotransmitters use _____________________ and ______________________endocytosis, exocytosisEndocytosis can be _________________ or __________________pinocytosis, receptor-mediated endocytosis___________________= to engulf liquidpinocytosis____________________= bring the whole membrane inside cell (often to recycle ___________________)receptor-mediated endocytosis, membrane proteins_______________________= a type of endocytosis used to bring really ___________ things inside of the cellphagocytosis, bigAll vesicular transport ___________________requires energyCells use glucose metabolism to obtain energy for cellular processes. Glucose enters cells by _________________________________________________________________________________________________________________________________________active transport when extracellular glucose concentration is lower than intracellular concentration
Other sets by this creator
CHN-245 Quiz 1
18 terms
Verified questions
engineering
Verified answer
Other Quizlet sets
art
46 terms
1/4