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21 Cards in this Set
- Front
- Back
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Composition of membranes |
50% proteins 50% lipids |
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Facilitated Transport |
-move ions or molecules across the membrane |
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Transporters |
-undergo conformational changes to move ions or molecules across the membrane |
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Channels |
-form continuous pores through the bilayer, discriminate based on size and charge |
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Concentrations |
-move toward the side of lower concentration |
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Charge |
-move towards side of opposite charge |
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Electrochemical Gradient |
-concentration and charge |
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Passive Transport |
-does not require energy, down a electrochemical gradient |
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Active Transport |
-against electrochemical gradient, requires energy |
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Anchors |
-structural, stability to the membrane, control the shape of the cell and its position relative to other cells |
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Receptors |
-sense chemical signals outside, carry signal inside of cell, recognize specific signal |
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Enzymes |
-catalyze chemical reactions |
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Transmembrane Protein |
-peptide chain completely crosses the membrane, exposed to both sides, orientation is fixed (same side always faces cytosol) |
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Transmembrane segments |
-a helices, maximizes hydrogen bonding between polar backbone groups, hydrophilic center |
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Beta Barrel |
-occurs in few transmembrane proteins, hydrophilic (polar) inside, hydrophobic residues outside |
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Monolayer associated |
-contact hydrophobic interior, not exposed to both sides, amphipathic a helix |
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Lipid Linked |
-lipid molecules covalently linked to protein, lipid inside hydrophobic, protein associated with hydrophobic interior (not exposed) |
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Protein attached |
-not anchored into the lipid bilayer themselves, bind to another protein (non covalent bond), not exposed |
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Integral Membrane Proteins |
-cannot be removed from membrane without disrupting the bilayer -not fixed, they do not flip but can rock back and forth |
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Peripheral Membrane Proteins |
-removed from membrane under mild conditions |
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Purification |
-hydrophobic section must be covered with lipids or detergents for Integral Proteins |
