Term
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Definition
| create energy and intermediates of biosynthetic pathways. |
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Term
| substrate and products of TCA |
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Definition
| acetyl group --- 3NADH, 1FADH2, 1GTP |
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Term
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Definition
| make C-C bonds in absence of a P bond |
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Term
| is oxaloacetate a substrate of the TCA |
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Definition
| no, because it is regenerated w/in the cycle |
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Term
| what reaction does citrate synthase catalze? |
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Definition
| acetyl CoA + OAA --> citrate + CoASH |
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Term
| what reaction is catalyzed by isocitrate dehydrogenase? |
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Definition
| isocitrate + NAD+ --> alpha ketoglutarate + NADH + CO2 |
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Term
| what reaction is catalyzed by alpha ketoglutarate dehydrogenase? |
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Definition
| alpha ketoglutarate + NAD+ --> succinly CoA + NADH + CO2 |
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Term
| what is an example of substrate level phosphorylation in the TCA? |
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Definition
| conversion of succinly coA to succinate by succinate thiokinase. |
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Term
| what rxn is catalyzed by succinate dehydrogenase in the TCA? |
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Definition
| succinate + FADH --> malate + FADH2 |
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Term
| what rxn of the TCA is catalyzed by malate dehydrogenase? |
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Definition
| malate + NAD+ --> OAA + NADH |
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Term
| what is the difference between the e accepting capabilites of FADH and NAD+; aka why have 2 diff types of e- acceptors in the same cycle? |
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Definition
| FADH accepts e- in a single fashion while NAD+ accepts pairs of e; FADH is bound while NAD+ is not. |
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Term
| what happens to excess citrate from the TCA. |
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Definition
| excess citrate is transported to the cytosol where it is fed into the fatty acid and cholesterol synthesizing pathways. |
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Term
| what are the regulators of citrate synthase and how do they affect its activity. |
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Definition
| citrate synthase activity is upregulated by oxaloacetate and downregulated by citrate. |
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Term
| what is the rate limiting step/enzyme of the TCA? |
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Definition
| isocitrate dehydrogenase (converts isocitrate to alpha ketoglutarate). |
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Term
| how is isocitrate dehydrogenase regulated? by what compounds? |
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Definition
| isocitrate dehydrogenase is allosterically regulated. it is activated by ADP and inhibited by NADH. |
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Term
| how is alphaketoglutarate regulated in the TCA? |
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Definition
| it is inhibited by NADH, succinyl coA and GTP. |
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Term
| where do u get acetyl coA (pathways)? |
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Definition
| beta oxidation of fatty acids, pyruvate (glycolysis), ..... |
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Term
| how is the pyruvate dehydrogenase complex (PDC) regulated? |
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Definition
| it is inhibited by PDC kinase, acetyl coA and NADH; it is indirectly activated by pyruvate and ADP; it is directly activated by insulin. |
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Term
| what reaction does pyruvate carboxylase catalyze? |
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Definition
| co2 + pyruvate "+" biotin --> oaa |
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Term
| how is pyruvate carboxylase regulated? |
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Definition
| it is activated by acetyl coA and inhibited by acetyl coA derivatives. |
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