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22 Cards in this Set
- Front
- Back
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Where does fatty acid synthesis occur?
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-in the cytoplasm of most cells
*liver is major site |
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What are the three enzyme systems of fatty acid synthesis?
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1) biosynthesis of Palmitate from Acetyl-CoA
2) Chain elongation starting with palmitate 3) desaturation |
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List the intermediates for the biosynthesis of Plamitate.
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-acetyl-CoA to Acetyl-ACP to Acetyl synthase
-acetyl-CoA to malonyl-CoA to Malonyl-ACP -both paths become Acetoacetyl-ACP, then B-3-Hydroxybutyryl-ACP then Crotonyl-ACP then Butytyl-ACP then Palmitoyl-ACP and lastly Palmitate |
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What are the starting and end materials for Palmitate synthesis?
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-Acetyl-CoA and Palmitate
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Once the two paths merge, what is the 1, 2, 3, and 4th things to happen in Fatty Acid Synthesis?
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-condensation
-first reduction -dehydration -second reduction *further rounds of FA synthesis |
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What controls Fatty Acid Metabolism?
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-hormones such as Glucagon, epinephrine, and insulin
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What are the improtant control points?
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-release of fatty acids from adipocytes
-regulation of Carnitine Acyltransferase in the liver -regulation of acetyl-CoA carboxylase |
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What does high insulin do after a meal?
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-inhibits breakdown of stored fats and stimulates the synthesis of malonyl-CoA
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What does malonyl-CoA inhibit?
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carnitine acyl transferase I so fatty acids are not oxidized
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When fasting, what happens?
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-insulin level drops releasing breakdown of fats
-epinephrine and glucagon increase |
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What does the presence of citrate do to Acetyl-CoAcarboxylase?
What inhibits the active enzyme? |
-polymerizes it to a filamentous form of 4-8 million wt!
-polymer is active -Palmitoyl-CoA |
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What are the shapes of elongation intermediates?
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-CoA esters
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What desaturates (forms double bond) Acyl-CoA molecules?
Where does desaturation of FA occur? |
-NADH and O2
-on the ER |
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What are the most common fatty acids in animal lipids?
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-oleic acid
-palmitoleic acid |
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What are Fatty Acyl Desaturates?
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-membrane bound flavoproteins which require Cytochrome B5 and O2
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What are essential fatty acids?
What can they be used for? |
-fatty acids that the body can't make (ex; mammals can't make double bonds beyond 9th carbon so linoleic acid can't be made)
-can be used to synthesize polyunsaturated fatty acids |
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How do you synthesize Arachidonic acid?
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-from linoleic acid
-Linoeoyl CoA to y-Linoeoyl CoA to Eicosatrienoyl CoA to Arachidonyl CoA *all cis forms |
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What are isoprenoids called?
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-terpenoids
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What is the first step of terpenoid synthesis that occurs in all organisms?
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-Acteyl-CoA to Isopentenyl Pyrophosphate (IPP)
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What are the next 3 steps to synthesize Cholesterol?
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-IPP to Squalene
-Cyclization of Squalene -Conversion of Lanesterol to Cholesterol |
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What are the steps to get from Actyl-CoA to IPP?
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-acetyl-CoA to Acetoacetyl-Coa
-to HMG-Coa -to Mevalonic acid -to Pyrophosphomevalonic acid -and finally to IPP |
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How does Squalene get to cholesterol?
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-squalene to Lanosterol which goes to cholesterol
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