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25 Cards in this Set
- Front
- Back
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general structure of phospholipid bilayer
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outer layer
-neutral (sphingomyelin & P choline) inner layer -acidic (P ethanolamine, P serine & P inosital) |
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bilayer changes in aging RBC
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loses PL
leaves acidic residues P serine flips to outside (spleen recog & destroy) |
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sphingomyelin
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approximates chol in membrane
associates w/choline in cytosol |
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FA's transit through membranes (2 mechanisms)
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passive diffusion "flip"
FATP- protein med'd transfer |
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structure of phospholipid
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polar head group (all have OH)
-choline, serine, ethanolamine, glycerol, myo-inositol attached via Phosphodiester bond rest of mol is hydrophobic |
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phosphatidylcholine
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lecithin
neutral, ionic surround lipoproteins |
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phosphatidylethanolamine
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neutral, ionic
3 fewer C's than PC |
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phosphatidylserine
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acidic b/c COO-
signaling for old RBC |
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phosphatidylinositol
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polar head is neut
leaves neg bal (acidic) b/c not balance pdiester derived from G 6 phosphate associated with DM |
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phosphatidylglycerol
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surfactant
neutral head, acidic mol |
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most acidic PL
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cardiolipin (aka diphosphatidal glycerol)
2 PO3's, in bacteria only in inner memb of mito (mito=bact theory) |
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PL's that can have Ab's in lupus
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Pserine
Diphosphatidylglycerol (cardiolipin) |
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Plasmalogen
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can generate PAF- most toxic subs in body
phosphoether (not PL but looks like it) 30% of membrane plt aggn, HTN & ulcerogenic |
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sources of choline
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eggs, meat, wheat germ, soy beans
synthesized in liver |
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function of choline
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learning & memory
memb PL structures fetal brain dvt (15:1 fetus:mom at placenta) sm amt in breast milk suff for all baby needs essential nutrient (don't synth enough) liver not function w/o stem cell division neural tube defect (I of folate) |
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phospholipases
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PLA1- snake venom
PLA2 -cleave at C2 (FA) -destroy PAF -generate eicosos -make PAF from lysophospholipids PLC -cleaves at lipid domain -gives DAG & PIP -deficient in Neiman Pick PLD -cleaves at head -gen's phosphatidic acid |
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Hyaline membrane dz
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RDS (resp distress synd)
surfactant -dipalmitoyl lecithin -mostly PC and some PG -and SP A & B |
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tethering
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increases protein hydro philicity
maristic acid geranyl & farnasyl HLA- parasite use PI |
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phospholipase cleaves at lipid domain
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PLC
generates DAG & PIP problem is neimann pick |
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phospholipase that cleaves at polar head
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PLD
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phospholipase that generates lysophospholipids
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PLA2
gives FA for eicosanoids & lysophospholipids for PAF |
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general metabolism of phospholipids
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construct lipid
-glycerol kinase (ATP) -acyl transferase (get phosphotidic acid) -phosphatase (get DAT for PL or TAG) Construct polar head -trap choline via kinase -CDP choline is high energy donor Combine -PC diacyltransferase (kicks off CMP) |
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salvage pathway for PC
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diacyltransferase
DAG to CDP Choline to Phosphatidyl choline |
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denovo synthesis of PC
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methionine & SAM
ethanolamine + ATP add CTP (get CTP ethanolamine) add Diglyceride (get PE) add 3 SAM Gives PC & s adenosyl homocysteine |
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TAG synthesis
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need Glycerol 3 phosphate
-from kinase in liver -from DHAP (& dehydrogenase) in all cells make phosphatidic acid to DAG to TAG |
