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30 Cards in this Set
- Front
- Back
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What are the major classes of membrane transporters.
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1) ion channels
2)ATP dependent 3) water channels -aquaporins 4) solute channels |
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What modes of transport can water/solutes pass through membranes
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diffusion, carrier mediated (faciliated diffusion or active), vesicular, epithelial
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What are the general direction of diffusion and how do you solve for the flux of molecule movement?
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Molecules move from hi to lo conc.
flux= areaXconcentration gradient/distance of solutes moving Flick's law |
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If area is increased, how do the flux of diffusion change?
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flux increases, so solutes diffuse faster
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What factors influence diffusion across a membrane
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*temperature *molecular weight, solute conc, surface area, distance
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How does emphasyma affect diffusion?
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Aveoli destroyed (lose surface area) so less oxygen gets into the pbl
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How does fibrosis affect diffusion?
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Scarring of aveoli tissue so greater distance for oxygen to get into pbl
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What is the extracellular concentration of Na+?
What is the intracellular concentration of Na+? |
145mM
15mM |
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What can passively diffuse through the cell membrane?
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Small uncharged particles that are lipid soluble
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What is primary active transport?
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The use of ATP ex. NA/K ATPase, Ca++ ATPase, H+ ATPase
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When is the net flux = 0 in active transport, what is the gradient?
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At the maximum gradient
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When is the net flux = 0 in passive transport, what is the gradient?
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When there is no gradient and the movement of molecules is at equilibrium
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A carrier-mediated transport allows for which:
diffusion facilitated diffusion active transport? |
All of them
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When a molecule needs a protein carrier, what are the requirements?
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Specific binding site for a specific type of molecule causes a conformational change
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Why is there sugar present in the urine of a diabetic?
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There is super saturation of glucose transporters so there isn't enough transporters to move all of the sugar from the lumen to the pbl vessels so the extra is excreted
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What kind of diffusion usually involves uniport transports?
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facilitated diffusion
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Digitalis requires what kind of transport?
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P-active transport
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What is faciliated diffusion?
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passive Diffusion from hi to lo conc that a molecule needs a transport protein (usually uniport)
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What types of ATP-dependent transports are there?
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P-type (in cell membrane), V-type and F-type (in organelle cell membranes; ATP-binding cassette (ABC) transporter
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Describe how cystic fibrosis effects transports
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Defect in ABC transporter blocks Cl- and Na+ from leaving cell so water also doesn't leave the cell to thin mucous
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What is the role of Digitalis?
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Blocks Na+/K+ ATPase so that the Ca++/Na+ pump is no longer working because it is a secondary active transport. This keeps Ca++ inside of the cells Used for people with heart failure
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What is the kind of transport that uses ATP indirectly?
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secondary active transport
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How is glucose transported?
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Through faciliated diffusion and secondary active transport
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How do ions such as Na+ and K+ enter and exit a cell?
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protein channels, primary active transport, secondary active transport.....NOT simple diffusion
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How is oxygen and carbon dioxized transported?
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diffusion through bilayer
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How does water move through membrane?
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passively from low osmolarity to hi osmolarity through aquaporins
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How are amino acids transported?
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Through secondary active transport
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What are two ways to vesicular transport?
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endocytosis (pinnocytosis, phagocytosis, receptor-mediated endocytosis), exocytosis (secretion, replace parts of membrane)
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What do you have to pee alot when you drink?
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anti diuretic hormones are inhibited so aquaporins no longer are functioning to absorb water
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What is the difference between paracellular and transcellular transport pathways?
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paracellular=inbetween cells
transcellular=through cells |
