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21 Cards in this Set
- Front
- Back
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Where in the cell does the fatty acyl CoA synthetase reaction occur? What is this reaction essentially doing to the fatty acid? Is this reaction reversible?
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In the cytosol. It is activating the fatty acid so it can continue to be metabolized. This reaction is IRREVERSIBLE.
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Where does fatty acid activation happen?
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In the cytosol?
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How many ATP does fatty acid activation consume/produce?
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It consumes 2 ATP.
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How are long chain fatty acids transported through the mitochondrial membrane?
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They are esters of carnitine.
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How do medium chain fatty acids make it through the mitochondrial membrane?
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Simple diffusion.
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What is the rate limiting step in fatty acid metabolism?
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The CAT 1 reaction.
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What enzymes catalyze the transacylation of acyl groups from CoA to carnitine? Where does each reaction take place?
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CAT1 takes place on the outer mitochondrial membrane. CAT2 takes place on the mitochondrial matrix side of the inner membrane.
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What is a regulator of fatty acid metabolism? Is this in the fed or fasted state? What is the regulator a signal of?
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malonyl-CoA, acts in the fed state. It is a signal of fatty acid biosynthesis.
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How does beta oxidation basically work?
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It cleaves off an acetyl CoA from the fatty acid the then the new fatty acid (two less carbons) goes through the cycle again.
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What are the energetic byproducts of beta oxidation? How do you do the energy calculation for even chains?
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-Acetyl CoA (one for each cycle through) is calculated n/2. Each acetyl CoA is 12 ATP
-NADH is three ATP there are n/2-1 per fatty acid. -FADH2 is two ATP there are n/2-1 -Each double bond is -2ATP -ACTIVATION is -2ATP |
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What is MCAD deficiency? What are some characteristic features of MCAD deficiency?
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Medium chain beta oxidation is blocked. Happens 1/10,000 births. Hallmarks: most prevalent in N. European, hypoglycemia, lactic acidosis (lots of pyruvate produced), dicarboxylic acidurea (b/c omega oxidation happens)
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What happens in odd chain fatty acid oxidation?
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Normal beta- oxidation occurs until there are 5 left. The five is broken up into the normal 2 and then a 3C propionyl group. Propionyl is converted into succinyl CoA.
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What are the essential requirements for odd chain fatty acid synthesis?
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ATP, vitamin B12, biotin, bicarbonate, NAD, FAD
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What two enzymes are required for oxidation of unsaturated fatty acids?
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an isomerase and reductase. requires 2 ATP per double bond.
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What is alpha oxidation? What fatty acids does it occur in? What is a classic defect in alpha oxidation.
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Very long chain fatty acids. It is a MITOCHONDRIAL process that involves the alpha carbon and releases the carboxyl group as CO2. Refsum's disease is a defect in alpha oxidation.
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What is refsum's disease?
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A neurological disease because of the buildup of phytanic acid because of a defect in alpha oxidation.
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What is peroxisomal oxidation?
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Less efficient than beta oxidation. An electron is donated directly to the molecular oxygen and produces hydrogen peroxide. An enzyme in the peroxisome conversts the H2O2 into water and oxygen and OCTANOYL COA. the octanoyl is 8C and is transferred to carnitine to undergo beta oxidation.
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What is zellweger syndrome?
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A neurological disorder where there is a defect in the peroxisome.
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What cofactors are needed for even chain fatty acid metabolism?
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FAD and NAD+
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When is methonyl CoA produced?
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Fed state
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what does omega fatty acid oxidation produce?
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dicarboxyl fatty acids
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