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111 Cards in this Set
- Front
- Back
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Because membranes are _, they are selectively permeable barriers.
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amphipathic
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Because membranes are amphipathic, they are _ _ _.
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selectively permeable barriers
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Fig 11.1 A bilayer is permeable to small _ molecules and small _ _ molecules, and impermeable to _ and _ _ molecules
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hydrophobic
uncharged polar ions large polar |
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Permeable to bilayer?
1AAs 2Glucose 3ethanol 4CO2 5Mg2+ 6urea 7water 8N2 |
1n
2n 3y 4y 5n 6sometimes 7y 8y |
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Diffusion through the lipid bilayer is limited by 3 things
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size, ionic charge and polarity
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_ proteins mediate transport of most molecules and all ions across the membranes
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membrane
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3 types of transport across membranes are:
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simple diffusion
facilitated diffusion active transport and co-transport |
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simple diffusion across a membrane requires no _ and no _.
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energy
transporter |
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_ _ facilitate diffusion
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channel proteins
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facilitated diffusion requires no _ but needs a _.
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no energy
transporter |
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active transport and co-transport needs _ and _.
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energy and transporter
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most integral membrane tranport proteins have _-_ _ _
ie. aquaporin- facilitate the diffusion of water figure 11.8 |
trans-membrane alpha helices
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3 types of membrane transport proteins:
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ATP-powered pumps
ion channels transporters |
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3 types of membrane transporter proteins in the transporter class:
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uniporter
symporter antiporter |
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ATP-powered pumps use _ _ to power movement of specific ions or small molecules against their _ _
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ATP hydrolysis
electrochemical gradient |
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Ion channels permit movement of specific ions or water down their _ _.
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electrochemical gradient
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Transporters facilitate movement of specific _ molecules or _.
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small
ions |
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_ transport a single type of molecule down its conc gradient
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uniporters
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cotransport proteins are _ and _ that catalyze the movement of multiple molecules against its conc gradient
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symporters and antiporters
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_ move molecule in the same direction of molecule against its conc gradient.
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symporter
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_ move molecule in the opposite of the molecule going against the conc gradient
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antiporter
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ATP-powered pumps can/cannot go against conc gradient
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can
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Ion channels are the _ way to transport, diffuses like in a _. can be opened or closed
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fastest
line |
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Ion channels only go down/against conc gradient
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down
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Uniporters allows _# molecules at a time and goes through a _ change
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1-2
conformation |
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_ allows 2 dif molecules to go both down and one against and one down conc gradient at the same time.
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cotransports
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which transport mechanism doesn't require specific proteins? 1
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passive diffusion
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Which transport mechanism has the solute transported against the gradient? 2
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active and cotransport
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Which transport mechanisms are coupled with ATP hydrolysis? 1
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active transport
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Which transport mechanism is driven by movement of a cotransported ion down its gradient? 1
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cotransport
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O2, CO2, steroid hormones, and many drugs use _ _ to move across a membrane
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simple diffusion
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glucose and AAs use facilitated transport specifically use _ to move across a membrane
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uniporters
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ions and water use facilitated diffusion specifically use _ _ to move across a membrane
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ion channels
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ions, small Hydrophilic molecules, lipids use _ _ to move across a membrane specifically ATP-transport pumps
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active transport
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glucose and AAs also use cotransport aka _ to move across a membrane
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symporters
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various ions and sucrose also use cotransport aka _ to move across a membrane
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antiporters
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facilitated diffusion can be _ aka reach a max velocity. fig 11.4
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saturated
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Vmax in facilitated diffusion depends on number of _ _ in the membrane. fig 11.4
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transporter proteins
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Uniporter is faster than _ _
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passive diffusion
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Facilitated diffusion goes _ conc gradient but Km which is ______ will remain constant
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down
conc at which the rate of uptake is half maximal rxn rate and a measure of the affinity of conc of enzyme to turn substrate into product |
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_ carry one molecule at a time and go through _ _ to mediate transport
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uniporters
conformational changes |
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_ are specific for one species of molecule
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uniporters
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Uniporters have a concentration gradient aka _ _ and they ONLY use this so transport goes _ the gradient. fig 11.5
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stored energy
down |
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GLUT1 for D-glucose is fast transport method is an example of a _ transport system
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uniporter
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GLUT proteins are GLUT1-12. They have 12 membrane spanning double helices and have glucose binding sites on _ AAs. They all transport _ but are expressed in dif _ _.
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hydrophobic
sugars cell types |
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GLUT4 is only in _ and _ cells and respond to _ by increasing uptake of glucose to remove it from the blood
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fat
muscle insulin |
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Transport proteins can be purified and studied in artifical bilayer membranes called _.
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liposomes
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Liposome purfication of transport proteins...
GLUT1 is disrupted in membrane by _. phosopholipids mix with it to form _. |
detergents
liposome |
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_ _ causes water to move across membranes from area of low solute conc to high solute conc. Fig 11.6 _ _ is needed to prevent net water flow
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osmotic pressure
hydrostatic pressure |
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_ increases cell permeability to water and excess water intake can cause a cell to _ and _. fig 11.7
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aquaporin
swell burst |
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Aquaporins are _ _ that greatly enhance the rate of bulk flow of water across a membrane. _ and _ _ of water that allow it to pass. fig 11.8
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water channels
specificity conformational changes |
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ATP-powered pumps come in 4 classes:
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P-class= phosphorylation
V-class= vacuole (and lysosomes) F-class= mitochondria and chloroplasts ABC superfamily- ATP Binding Cassette |
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ATP-powered pumps: P-class pumps used in _ _ of plants, fungi, bacteria, and eukaryotes, _ _ _of mammalian stomach, _ _ of all cells in eukaryotic cells, and _ _ _ in muscle cells
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PM
apical PM PM sarcoplasmic reticulum membrane |
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ATP-powered pumps: P-class pumps use energy from _ _ to drive transport against a conc gradient
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ATP hydrolysis
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ATP-powered pumps: P-class pumps have 2 catalytic alpha subunits which are _ as part of transport cycle. Also has 2 beta subunits which are used for _
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phosphorylated
regulation |
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ATP-powered pumps: P-class pumps for _ to pump various ions
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phosphorylation
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ATP-powered pumps: P-class pumps has subunits that are _ _ _
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integral membrane proteins
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ATP-powered pumps: V-class pumps are used in V_ and _. They have a complex subunit structure that is _ and _.
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Vacuoles
lysosomes integral peripheral |
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ATP-powered pumps: V-class pumps found in _ _ of fungi, plants, and yeast; in _ and _ _ in animal cells; and _ _ of osteoclasts and some kidney tubule cells
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vacuolar membranes
endosomal and lysosomal membranes plasma membranes |
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ATP-powered pumps: V-class pumps only pumps _
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H+
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ATP-powered pumps: F-class pumps are in _ and _. they have complex subunit structure with intergral and peripheral parts like the _-class. fig 11.9
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mitochondria
chloroplasts V-class |
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ATP-powered pumps: F-class pumps found in _ PM, _ _ membrane, _ membrane of chloroplast
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bacterial
inner mitochondrial thylakoid |
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ATP-powered pumps: F-class pumps only pumps _ which it uses as a gradient to make _. fig 11.9
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H+
ATP |
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ATP-powered pumps: ABC superfamily is very diverse function from _ PM to _ PM.
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bacterial
mammalian |
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ATP-powered pumps: ABC superfamily: 4 domains that contain 2 _ domains (channel) and 2 cystolic _-_ domains which all can consist of 1, 2, or 4 proteins. fig 11.9
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transmembrane
ATP-binding |
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_ _ and _ _ are maintained across the PM in ATP-powered pumps.
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ionic gradients
electric potential |
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ATP-powered pumps: _-class example where muscle Ca2+ ATPase pumps Ca2+ ions from the cytosol into the SR. There is both _ _ and _ _ with a distinct order of individual steps aka 2 Ca2+ per cycle fig 11.10
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P-class
conformational changes pump phosphorylation |
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Liposome purfication of transport proteins...
GLUT1 is disrupted in membrane by _. phosopholipids mix with it to form _. |
detergents
liposome |
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_ _ causes water to move across membranes from area of low solute conc to high solute conc. Fig 11.6 _ _ is needed to prevent net water flow
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osmotic pressure
hydrostatic pressure |
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_ increases cell permeability to water and excess water intake can cause a cell to _ and _. fig 11.7
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aquaporin
swell burst |
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Aquaporins are _ _ that greatly enhance the rate of bulk flow of water across a membrane. _ and _ _ of water that allow it to pass. fig 11.8
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water channels
specificity conformational changes |
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ATP-powered pumps come in 4 classes:
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P-class= phosphorylation
V-class= vacuole (and lysosomes) F-class= mitochondria and chloroplasts ABC superfamily- ATP Binding Cassette |
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ATP-powered pumps: P-class pumps used in _ _ of plants, fungi, bacteria, and eukaryotes, _ _ _of mammalian stomach, _ _ of all cells in eukaryotic cells, and _ _ _ in muscle cells
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PM
apical PM PM sarcoplasmic reticulum membrane |
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ATP-powered pumps: P-class pumps use energy from _ _ to drive transport against a conc gradient
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ATP hydrolysis
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ATP-powered pumps: P-class pumps have 2 catalytic alpha subunits which are _ as part of transport cycle. Also has 2 beta subunits which are used for _
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phosphorylated
regulation |
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ATP-powered pumps: P-class pumps for P_ to pump various ions
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phosphorylation
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ATP-powered pumps: P-class pumps has subunits that are _ _ _
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integral membrane proteins
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ATP-powered pumps: V-class for _ and _. they have complex subunit structure with integral and peripheral parts
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vacuole
lysosome |
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ATP-powered pumps: V-class only pumps _
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H+
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ATP-powered pumps: F-class are in _ and _
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mitochondria
chloroplasts |
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ATP-powered pumps: F-class only pumps _ and uses that as a gradient to make _.
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H+
ATP |
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ATP-powered pumps: ABC superfamily are _ _ _ and are very diverse.
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ATP Binding Cassette
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ATP-powered pumps: ABC Superfamily has 4 domains consisting of 2 _ domains (channel) and 2 cytosolic _-_ domains
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transmembrane
ATP-binding |
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_ _ and an _ _ are maintained across a plasma membrane
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ionic gradients
electric potential |
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ATP-powered pumps: P-class found in muscles with _ _ pumps which move Ca2+ ions from cytosol into SR.
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Ca2+ ATPase
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ATP-powered pumps: P-class muscle Ca2+ ATPase goes through _ _ and _ _ and has a distinct order of steps with 2 Ca2+ per cycle. fig 11.10
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conformational changes
pump phorphorylation |
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ATP-powered pumps: P-class muscle Ca2+ ATPase allows _ to _
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muscles
relax |
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ATP-powered pumps: P-class muscle Ca2+ ATPase has multiple _ _ _ with 4 that bind Ca2+ during transport and involves _ _. fig 11.11
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transmembrane alpha helices
conformational changes |
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ATP-powered pumps: P-class PM Na+/K+ ATPase maintain _ Na+ and K+ in animal cells
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intracellular
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ATP-powered pumps: P-class PM Na+/K+ ATPase has _# Na+ _ and _# K+ _ per cycle. Overall it goes through _ _ and _ _ and has a distinct order of steps fig 11.12
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3 Na+ out
2 K+ in conformational changes pump phosphorylation |
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ATP-powered pumps: V-class: H+ ATPases that move protons across _ and _ membranes.
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lysosomal
vacuolar |
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ATP-powered pumps: V-class ALONE generate an _ _.
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electric potential
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ATP-powered pumps: V-class WITH ANION CHANNEL (Cl-) have no _ _ but have an _ interior. fig 11.13
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electric potential
acidic |
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ATP-powered pumps: ABC superfamily transports a variety of substrates (7)
e.g. E. coli lipid flippase or mammalian MDR1 fig 11.14 and fig 11.15 |
AAs, peptides, sugars, nucleotides, lipids, toxins, drugs, etc
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Energy across a membrane uses selective movement of ions and creates a _ _ _ difference. If theres is _ _ then there is no electric potential. fig 11-17
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transmembrane electic potential difference
no movement |
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_ _ are ionic charge gradient plus conc gradient.
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electrochemical gradient
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The membrane potential in animal cells depends largely on _ _ _. fig 11.18
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K+ resting potential
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membrane potential involves _ flows out of cell until the _ _ pushing back on it equals the _ _ pushing out on it. fig 11.18 Resting is about -70
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K+
electric potential ionic gradient |
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K+ channels are _. fig 11.19
they are highly selective only for K+. |
homotetramers
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Homotetramers aka K+ channels have ionic charges that are shielded by water with a _ _ which is then lost in the channel.
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hydration shell
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Homotetramers aka K+ channel protein is taken over by _ _ for shielding. Na+ is _ so it can't properly be shielded. fig 11.20
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carbonyl oxygens
small |
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Na+ entry into mammalian cells has a _ change in G (free energy) bc of the combo of _ _ and _ _
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negative
concentration gradient membrane potential |
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Na+ entry into mammalian cells is used as an _ _. e.g. coupled movement of ions and small molecules, nerve and muscle cells action potentials. fig 11.24
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energy source
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_ is co-transport that moves ions and small molecules against conc gradients and both species travel in the same direction. fig 11.25
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symporter
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Symporter involves the _ _ gradient with glucose which involves a conformational change.
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Na+ double
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_ are a contransport that moves ions and small molecules against the conc gradient and the species travels in opposite directions
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antiporter
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Antiporter e.g. Cl- is _ in cells so import is favorable until it is matched by neg membrane potential so in total they help regulate cellular _.
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low
pH |
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A plant vacuole uses _ _ input Cl- and NO3- into cell, _ to exchange H+ for Na+, Ca2+, and sucrose; and _-class ATPase pumps to move H+ into cell. fig. 11-28
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ion channels
antiporter V-class |
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Transepithelial transport of glucose from the intestinal lumen into the blood which goes from lumen (has high _) through _ transport system with Na+/glucose to cytosol (low _/high _) then to blood (high Na+/low K+= regulated by _-class Na+/K+ ATPase. e.g. of rehydration therapy. fig 11.29
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lumen: NaCl
symporter low Na+/high K+ P-class |
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Transepithelial transport involves _ junctions, _ vs _ membranes, and _ distribution of transporters in the membranes.
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tight
apical and basolateral asymmetric |
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Transepithelial transport in the stomach involves the acidification of stomach lumen by _ cells where lumen has pH of 1.0 uses _ and _ ion channels into lumen and also the _-class pump called H+/K+ ATPase then Cl-/HCO3- _ on basolateral membrane to balance.
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parietal
Cl- and K+ P-class antiporter |
