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31 Cards in this Set
- Front
- Back
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where does CAC take place
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in the mitochondria
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how many carboxylic acids are on citrate?
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3 - a tricarboxylic acid.
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How does pyruvate get from the cytosol to the mito matrix?
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by an antiporter, pyruvate carrier.
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what happens to pyruvate once it gets into the mito matrix?
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it is oxidatively decarboxylated by pyruvate dehydrogenase complex.
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what links glycolysis and CAC?
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oxidative decarboxylation of pyruvate to give acetyl CoA and CO2
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What does CoA do?
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carries Acyl groups
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What are the components of CoA?
What is the reactive part? |
B-mercaptoethylamine unit
Pantothenate Unit ADP The thiol SH |
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how does acetate enter the CAC?
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thioester bonded to CoA.
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what's the diff between ATP and GTP?
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adenine and guanine
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What is Thiamine Pyrophosphate? (TPP)
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The prosthetic group of E1 on pyruvate dehydrogenase complex.
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what is the function of TPP?
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decarboxylate pyruvate
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what is the function of lipoamide?
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oxidize
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what is the function of Coenzyme A in PDHC?
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Acyl carrier
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What is the purpose of FAD in PDHC?
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to reoxidize lipoamide
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what is the function of NAD+ in PDHC?
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to reoxidize FADH2
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how come the reactive part of TPP is reactive?
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The Carbon atom is between N and S, so very stable anion - acidic; deprotonates because pka is about 10.
Then the anion adds to pyruvate to form tetrahedryl intermediate. |
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E2 of PDHC
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dihydrolipoyl transacetylase
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What is E3 of PDHC?
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Dihydrolipoyl dehydrogenase
-Oxidizes dihydrolipoamide to regenerate the coenzyme lipoamide. |
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what is the reactive center of TPP?
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a thiazolium ring (acidic carbon between a nitrogen and sulfur)
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how many atoms make up the long lipoamide arm of lipoic acid/lysine?
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12
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what are the reactions that take place at E1 of PDHC?
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1. Decarboxylation - add pyruvate to TPP, give of CO2.
2. Oxidation - oxidize TPP back, transfer Acetyl concomiantly to Lipoamide. |
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what are the reactions that take place at E2 of PHDC?
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only one; transfer of acetyl from acetyllipoamide to CoA to leave dihydrolipoamide (reduced form).
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How many enzymes and cofactors are in PDHC
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3 enzymes
5 cofactors |
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What are the 5 cofactors in PDHC
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TPP
Lipoamide Coenzyme A NAD+ FAD |
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What plays a central role in formation of Acetyl CoA from Pyruvate?
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LIPOIC ACID'S LONG ARM.
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What are the steps of PDHC?
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1. Thiamine Pyrophosphate decarboxylates
2. Lipoamide Oxidizes the Acetyl group and transfers it to Coenzyme A. 3. FAD reoxidizes Lipoic Acid back to Lipoamide. 4. NAD oxidizes FADH2 back to FAD. |
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What is the reactive center of TPP?
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A thiozolium group
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What is lipoamide linked to on WHICH ENZYME?
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a Lysine residue on Enzyme 2
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What are the cofactors bound to each subunit in TPHC?
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E1: TPP
E2: Lipoamide, CoA E3: FAD, NAD+ |
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What is a synthase
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an enzyme catalyzing a synthetic reaction in which 2 units are joined w/out participation of ATP or NTP
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what are control points for the CAC?
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KDHC
PDHC isocitrate dehydrogenase |
