BIO 205: Fatty Acid Metabolism
31 Cards in this Set
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Movement of short fatty acids
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can move across lipid membranes on their own, entering the intestinal cells on one side and crossing the blood stream on the other side
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Movement of longer fatty acids
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require transporters to help them enter the epithelial cells, once inside they are combined with glycerol to make triacylglycerols that become part of chylomicrons
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Lacteal
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vessels in the villi which drain into lymph vessels in the submucosal layer, pick up large chylomicrons
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Hepatic portal vein
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capillaries carry nutrients to the hepatic portal vein which enters the liver
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Hepatic vein
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blood exits the liver via the hepatic vein after nutrients have been removed
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Where does fluid in the lymph system drain into?
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drains into the left subclavian vein
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Carnitine shuttle
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inner mitochondrial membrane has a transporter which carries carnitine back and forth between the intermembrane space and the matrix
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Structure of carnitine
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includes an alcohol group capable of joining in an ester bond to a fatty acid
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Reaction with carnitine for the movement of fatty acids
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Fatty acid-S-CoA +HO-carnitine---->FA-O-carnitine+HS-CoA
FA-O-carnitine + Co-SH---->FA-S-CoA + OH-carnitine
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Steps in beta oxidation
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two hydrogens removed from the chain to form a double bond
water then attacks the double bond to add an OH at the beta position
two hydrogens removed from the beta position to form a C=O at the beta position
H-SCoA attacks at the beta position to form a two carbon acetyl group and a sh…
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Spending of ATP in beta oxidation
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1 ATP spent to prime palmitate to get FA-S-CoA
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NADH and FADH2 generated from the meat-slicer reactions of beta oxidation
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each meat-slicer step has two reduction steps, generating 1 NADH and one FADH2 per step for a total of 7 NADH and 7 FADH2
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Generation of energy from the TCA cycle
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each Ac-CoA run through the TCA cycle generates 1 ATP, 3 NADH, and 1 FADH2
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Efficiency of beta-oxidation as compared to glycolysis
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breakdown of fats is far more efficient than the breakdown of carbohydrates
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Similarities betwen FA synthesis and breakdown
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two dehydrogenation steps, one hydration, and the loss/addition of two carbons
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Energy molecule used in fatty acid synthesis
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NADPH is used to provide energy, not NADH or FADH2
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Thiol-carrying molecule used in fatty acid synthesis
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uses an acyl carrier protein
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Where does fatty acid synthesis occur
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occurs in the cytoplasm of the cell, whereas beta-oxidation occurs in the mitochondrion
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Products of fatty acid synthesis
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malonyl-CoA is used instead of acetyl-CoA like beta-oxidation
one of the carbons has a COOH group that can be lost as a CO2 group to add to the chain
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Where are carbons added in fatty acid synthesis?
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added at the carboxy end of the fatty acid chain, inserting between the chain and the acyl carrier protein
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Differences between NAD and NADPH
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extra phosphorus does not provide any chemical effect in NADPH because it is so far away from the nicotinamide ring, and does not affect the delta G of the NADPH-->NADP+ equilibrium
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Structure of malonyl-CoA
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formed from 3 carbon malonic acid, has a s-CoA in place of the OH group on one of the carboxylic acids
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Reaction that converts Ac-CoA to Malonyl-CoA
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Ac-CoA + HCO3- + ATP---> malonyl-CoA + ADP + Pi
catalyzed by malonyl-CoA synthetase
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Ratio of reduced to oxidized forms of NADPH and NADH in the liver
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high levels of NADPH as compared to NADP+
High levels of NAD+ as compared to NADH
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Excess NADPH is favorable for?
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creates a strong reducing environment for making fatty acids
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Excess NAD+ is favorable for?
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strong oxidizing environment for converting glucose into pyruvate
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Regulation of glycogen catabolism and glycogen anabolism
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regulated by adrenalin and glucagon to initiate glycogen catabolism and insulin to initiate glycogen anabolism in the cytoplasm
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Regulation of fatty acid synthesis and bglycogen catabolism
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regulated by the levels of NADH and NADPH in the cytoplasm
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Regulation of fatty acid synthesis and breakdown
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regulated by differences in locations, fatty acid synthesis occurs in the cytoplasm and breakdown in the mitochondrion
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Response to emergency-induced release of adrenalin
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cAMP-dependent many-protein kinase chain is activated
leads to breakdown of glycogen into glucose-1-phosphate and breakdown of TAG's into glycerol and fatty acids
fatty acids are picked up by surface of serum albumin and transported to liver and muscle cells
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What occurs when fatty acids are transported to liver and muscle cells
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fatty acids are joined to CoA and transported to mitochondrion by carnitine shuttle
beta-oxidation of the fatty acids generates acetyl-coA which feeds into the Kreb's cycle
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Bio 205: Test Flashcards