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42 Cards in this Set
- Front
- Back
Cell membranes
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Selectively permeable.
Provide protection. House receptor. Provide sites for transport. Organize life processes. |
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Cell membranes
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Consist mostly of a phospholipid bilayer with protein molecules.
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Phospholipid
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phosphate group and 2 fatty acids bonded to 3 carbon glycerol.
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Phospholipid
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Has a hydrophilic head, and hydrophobic tail.
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Amphipathic
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Molecules with hydrophobic and hydrophilic regions.
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(Amphipathic)Phospholipid
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Self-assemble into a double-layered sheet.
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Hydrophobic Tails
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Core
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Hydrophilic phosphate groups
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Both surfaces.
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Fuid Mosaic Model
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Variety of molecules, carbs/proteins that form the membrane and move freely through it.
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Cell Membranes Consist Of
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Proteins, Cholestrol, Carbs, and phospholipids.
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Selectively Permeable
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Proteins function as pores. Membrane bound proteins promote movement of ions/molecules in or out of cells.
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For a cell or organelle to function properly:
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Membranes must be physically/chemically complete.
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What ions must routinely move across cell membranes?
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Lipid soluble molecules ie.oxygen, small uncharged polar ie.carbon dioxide and water.
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How could membranes promote the movement of ions out of or into cells?
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Membrane bound proteins.
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How could membranes restrict the movement of ions out of or into cells?
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Phospholipid bilayer.
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Could a cell survive without an intact cell membrane?
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No, because barrier to simple diffusion.
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Permeability
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Depends on solubility and size of molecules.
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Betacynin
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Reddish pigment located in large central vacuoles of cells.
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Tonoplast
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Vacuolar membrane.
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High Temps
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Cause molecular collisions that destroy membranes.
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Selectively Permeable
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Proteins function as pores. Membrane bound proteins promote movement of ions/molecules in or out of cells.
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For a cell or organelle to function properly:
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Membranes must be physically/chemically complete.
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What ions must routinely move across cell membranes?
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Lipid soluble molecules ie.oxygen, small uncharged polar ie.carbon dioxide and water.
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How could membranes promote the movement of ions out of or into cells?
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Membrane bound proteins.
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How could membranes restrict the movement of ions out of or into cells?
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Phospholipid bilayer.
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Could a cell survive without an intact cell membrane?
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No, because barrier to simple diffusion.
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Permeability
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Depends on solubility and size of molecules.
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Betacynin
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Reddish pigment located in large central vacuoles of cells.
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Tonoplast
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Vacuolar membrane.
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High Temps
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Cause molecular collisions that destroy membranes.
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Freezing Temps
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Cause water to crystallize and expand because of hydrogen bond alignment-ruptures membranes.
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Which temp. damaged membranes the most? The least? How do you know?
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-5C/most,20C/least. Because of color of water.
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What is more damaging to membranes? Why?
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Extreme cold, because water molecules expand and rupture membrane.
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Why does freezing temp. require more time?
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Water expands when it freezes because it needs more time for hydrogen bond alignment.
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Organic solvents
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Dissolve a membrane's lipids.
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Acetone
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Has the greatest ability to dissolve lipids. Damages membranes the most.
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Are lipids soluble in both acetone and methanol?
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Yes.
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What damages membranes more?
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50% Methanol.
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Which solvent are lipids more soluble?
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Acetone.
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Did the highest concentration of both solvents cause the most damage?
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Yes.
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What other solvents might be interesting to test in this experiment?
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Bleach, amonia, vinegar.
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What was the purpose of tube7?
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Control.
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