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35 Cards in this Set
- Front
- Back
major classes of membrane compounds
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cholesterol and phospholipid
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myelin is primarily what compound?
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lipids
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the inner mitochondrial membranes are primarily made of what compound?
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protein
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the major components of eukaryotic cell membranes?
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glycerophospholipids
sphingophospholipids cholesterol |
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phosphoric acid and fatty acid chains are attached to glycerol through what mechanism?
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esterification
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which carbons have the fatty acid chains in glycerophospholipids?
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1 and 2
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the most common glycerol-phospholipids in membranes?
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phosphatidylcholine and phosphatidylethanolamine-positively charged head groups
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another name for phosphatidylethanolamine?
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cephalin
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another name for phosphatidylcholine?
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lecithin
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glycerolphospholipids with negative polar head groups?
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phosphatidylinositol
phosphatidylserine cardiolipin |
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another name for cardiolipin?
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diphosphatidylglycerol-two phosphatidic acids linked by a glycerol
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where is cardiolipin found?
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mitochondrial inner membranes and bacterial membranes
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the backbones for sphingolipids
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sphingosine and dihydrosphingosine
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what is a ceramide?
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a spingosine with a saturated or unsaturated fatty acid chain in amide linkage on the amino group
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ceramide is similar in structure to what molecule?
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diacylglycerol
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what is sphingomyelin made of ?
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ceramide and phosphorylcholine
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the most abundant sphingolipid in mammalian tissues?
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sphingomyelin
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what is esterified at C1 of sphingomyelin?
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phosphorylcholine
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how does cholesterol effect membrane fluidity?
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increase cholesterol-decrease fluidity
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in what disease does the concentration of cholesterol incr.?
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cirrosis of liver in hepatocytes
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membrane with the highest % of sphingolipids
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plasma membranes
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intracellular membranes are primarily made of what compound?
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glycophospholipids
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what membranes are intermediate in lipid concentration?
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mitochondria, nuclei, rough ER, golgi
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what movements of individual membrane molecules are most likely?
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within their own monolayer, NOT FLIP-FLOP
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where is the membrane most viscous?
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close to the lipid head groups
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what are liposomes?
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artificial membranes formed by mixtures of glycerophospholipids
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how fast do membrane proteins redistribute?
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around 40 minutes
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what lipids are primarily found in the outer leaflet of erythrocytes?
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sphingomyelin and phosphatidylcholine
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what lipids are primarily found in the inner leaflet of erythrocytes?
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phosphatidylethanolamine and phosphatidylserine
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what are the transmembrane segments of integral membrane proteins made of?
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hydrophobic amino acids
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functions of membrane proteins
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1 movement of charged and uncharged molecules
2 receptors for hormones and growth factors 3 enzymes for transduction of signals 4 maintenance of cell shape |
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what is contained in pockets of unsaturated cis double bonds?
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water and small ions
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why does cholesterol reduce fluidity?
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reduces the coiling of fatty acid chains
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Ca2+ effect on membrane fluidity?
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decrease because of interaction with negatively charged phospholipids
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where is fluidity greatest?
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the membrane middle, less physical constraint
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