Term
| Diffusion across a lip bilayer |
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Definition
- Bilayers have selective permeability
- High perm; small molecules and molecules that play nice with hydrophobes; o2/Co2/N2/ steroids/water
- Low perm for large molecules or those that dont play nice = sucrose/gluc, ions |
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Term
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Definition
- High Outside; Na+, Mg+, Ca. Cl-
- High Inside; K+, H+ |
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Term
| Membrane Transport Proteins |
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Definition
- Move ions across LB's
- carrier proteins cycle through two or more conformational states and transport a defined number of solutes per cycle
- Channel Proteins; pore which solutes move through |
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Term
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Definition
| - ~10 mill molecules/trans molecule/sec |
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Term
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Definition
| - ~100 molecules/transport mol/sec |
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Term
| Kinetics of Facilated diffusion |
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Definition
| - FD is solute spec, proportional to solute at low concentration, saturable at high concetration, spec inhibitable |
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Term
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Definition
- Facilitated diffusion
- Are small mols
- Interact fav with hphobic core of lip bi
- interact fav with ion
- facilatate the movement of the ion
ex; Channel gramicidin (17 AA, 1 hphobe)
Carrier Valinomycin (12 hydrophic AA, K+) |
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Term
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Definition
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Term
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Definition
| Movement of two molecules across same dir |
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Term
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Definition
| Transport molecules opposite directions |
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Term
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Definition
| - Movement of charged solutes by simple dif is modulated by mem potential |
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Term
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Definition
| - Move down chemical or electrochem gradient, FDif |
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Term
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Definition
- Uses energy to move solute against gradients
- Sources ATP (primary), gradient (secondary, antiporters)
- Light (plants and bacteria) |
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Term
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Definition
- Primary Active Transport - Hydrolysis of one ATP mol. 3 Na out and 2K in - Electrogenic - Oubain inhibits - Consumes 1/3 of cell energy and 2/3 for nerve cells - Important for pH bal, osmotic bal, other t port
- ATP binds to protein allows Na to bind
- Na binding causes confirmational shift and phosph asp by ATP
- Phosphorylated protein has low Na affinity and Na is released
- K binds which dephosphorylates asp and changes back to normal confirmation with K attached inside
- unphos likes na more than k and atp rebinds |
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Term
| General Mechanism of Na+/K+ Atpase |
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Definition
- NA dependant phosphorylation
- Confirmational shift
- Ka-dependant |
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Term
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Definition
- Symporter; Ion-driven
- Secondary active
- Couples glucose moving against its gradient with NA moving along its gradient
-ex;SGLT |
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Term
| Coupling of transport mechanisms |
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Definition
- Ex; NA/K Atpase and NA+Gluc Symporter
- Na K creates low Na in cytosol
- SGLT on apical surface takes up gluc and Na symports them. Gluc against; sodium with
-GLUT-2 allows glucose to move down gradient into extracell fluid on basolateral side
- SGLT |
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Term
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Definition
- ATP Binding Cassette
- 2 MultiP domains and 2 ATP binding cassettes
- ATP binding causes dimerization (outward facing)
- ATP hyrdolysis causes dissociation (inward facing)
- Change allows substrate transport |
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Term
| ABC's are used in and how? |
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Definition
- Immune response; TAP Transporter associated with Antigen Processing
- Viral protein in cytosol are broken down by proteosome
- Translocated into ER luman by TAP
- Peptides are then bound by classI molecules in ER
- Peptide+Class1 complex trafficked to cell surface for recog by Killer T lymphos |
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Term
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Definition
- Flexible/Fluid
- Selective perm; high for water low for salts
- In hypertonic cell cell blebs because of spectrin cytoskel resisting shrivelling
- Hypotonic swells and eventually lyses |
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