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24 Cards in this Set
- Front
- Back
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Overview of what fatty acid synthase complex does
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- Malonyl CoA adds 2 carbons onto Acetyl CoA in a cycle
- Continues until 16 carbon chain is made (palmitate) and then released |
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What sets up fatty acid biosynthesis
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- High carbohydrate and insulin levels generates extracellular OAA and NADPH for fatty acid synthesis
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An increase of insulin causes what three enzymes to increase which encourages fatty acid synthesis by producing more extracellular OAA and NADPH?
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- PDH (pyruvate to acetyl CoA)
- Citrate Lyase (Citrate to OAA) - Malic enzyme (Malate to Pyruvate, releasing NADPH) |
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Why is Linoleic acid essential?
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- only way to get arachidonyl CoA
- body can only create double bonds from the carboxylic acid end to the 10th carbon - need to have dietary lipids |
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What conditions must be met to encourage triglyceride synthesis?
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- Fed state: high insulin/glucose
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What are the steps for triglyceride synthesis?
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1) Liver converts glycerol to G3P
OR 1) Liver/Adipose converts Glucose to DHAP to G3P 2) Add 2 fatty acids to first and second position (Phosphatidic acid) 3) remove phosphate (Diacyclglycerol) 4) Add fatty acid to the third position 5) liver: goes to VLDL and into blood OR 5) adipose: goes to lipid droplet |
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What phospholipases remodel glycerophospholipids and where?
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A1: Fatty Acid #1
A2: Fatty Acid #2 C: cleaves off phosphate+ head group D: cleaves off head group |
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What are the precursors to ether-linked phospholipids?
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- MDHAP and Fatty Alcohol
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What ether-linked phospholipids are we concerned with?
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- Alkyl ether lipids (ie platelet activating factor)
- plasmalogens (ie arachidonic acid storage) |
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What is the difference between a sphingolipid and a glycerophospholipid?
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- Sphingolipid contains a ceramide backbone
- Glycerophospholipid contains a diaglycerol backbone - glycerophospholipids can add onto sphingolipids |
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What does spingomyelinase do?
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Breaks sphingolipids into ceramides
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What does ceramidase do?
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Breaks ceramide into sphingosine and fatty acids
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What causes Farber's disease?
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- ceramidase deficiency so ceramide cannot be broken down into sphingosine and fatty acids
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What are the symptoms of Farber's disease?
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- joint swelling/deformities
- subcuntaneous nodules (all b/c ceramide accumulation) |
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Where is fatty acids predominantly synthesized?
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- fat and liver cells
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What is the biosynthetic pathway for glycerophospholipids?
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- Glycerol 3-P to Phosphatidic Acid
- 2 pathways 1) to CDP-Diacylglycerol which can make a) cardiolipin via phosphatidylglycerol b) phosphatidylinositol (PI) via Inositol 2) Diacylglycerol can form a) phosphatidylcholine via CDP-choline b) Phosphatidylethnolamine via CDP-ethanolamine |
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How can Phosphatidylcholine and Phosphatidyethanolamine interconvert? (glycerophospholipids)
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- 3 SAM
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How do Phosphatidylethanolamine and Phosphatidylserine interconvert? (glycerophospholipids)
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- Phosphatidylserine to Phosphatidylethanolamine: release of CO2
- opposed: addition of Serine |
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What are 3 subclasses of phospholipids and how do they differ?
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- Diacyl Ether (ester at SN-1)
- Alkyl Ether (alkyl ether at SN-1, platelet activating factor) - Plasmalogen (vinyl ether at SN-1, primarily in heart) |
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What is the biochemical pathway for the first step in sphingolipid synthesis?
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***create backbone, ceramide
- condensation of serine + palmitoyl CoA (by PLP) - reduce to form dihydrosphingosine - add fatty acyl group - oxidize |
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Second step in sphingolipid synthesis, addition of side groups
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- 3 pathways
1) add phosphatidylcholine to get Sphingomyeline 2) add UDP-Galactose for Galactocerebroside - add sulfate to get Sulfatide 3) add UDP- Glucose for Glucocerebroside - add UDP-sugar/CMP-NANA for Ganglioside - further breakdown of Glucocerebroside into Globoside |
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What are the roles of ceramide?
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- part of barrier that make skin water tight
- part of apoptosis - mediator of tumor necrosis factor activity |
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What is the rate limiting step for fatty acid synthesis?
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- the conversion of acetyl CoA to malonyl CoA catalyzed by acetyl CoA carboxylase
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Remodeling of phospholipids at sn3 is regulated by?
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- PLD or PLC initiates
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