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44 Cards in this Set
- Front
- Back
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What are the 3 products from oxidizing pyruvate?
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CO2, 2e- AND Acetyl CoA
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What are the 3 products from the citric acid cycle?
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GTP, 8e-, AND 2 CO2
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What's the product from the oxidation of glucose in glycolysis?
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pyruvate
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What catalyzes the formation of acetyl CoA from pyruvate?
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pyruvate complex (PDH)
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PDH is similar in structure and mechanism to what in the TCA cycle?
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alpha ketoglutarate dehydrogenase
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PDH complex is inhibited by
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acetyl-CoA and NADH
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PDH complex is activated by
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CoA (CoASH) and NAD+.
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where does TCA cycle take place?
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in the matrix of the mitochondrion
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The TCA cycle begins with the transfer of a two-carbon acetyl group from acetyl-CoA to ---------
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the four-carbon acceptor compound (oxaloacetate) to form a six-carbon compound (citrate).
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What enzymes are part of the irreversible stages in the TCA cycle?
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Isocitrate dehydrogenase AND α-Ketoglutarate dehydrogenase
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What enzymes in the TCA cycle generate NADH?
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α-Ketoglutarate dehydrogenase AND Malate dehydrogenase AND Isocitrate dehydrogenase
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What is rate-limiting stage (irreversible) in TCA cycle?
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Oxaloacetate +
Acetyl CoA + H2O = Citrate + CoA-SH |
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What are the products in the first turn of the TCA cycle?
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one GTP (or ATP), three NADH, one QH2, two CO2
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NADH, a product of all dehydrogenases in the TCA cycle with the exception of
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succinate dehydrogenase
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What reactions are included in transforming pyruvate to acetyl CoA?
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decarboxylation, oxidation, and transfer of CoA
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What regulates PDH?
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reversible phosphorylation
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Is the phosphorylated enzyme (PDH) active?
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no, inactive
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Is the dephosphorylated enzyme (PDH) inactive?
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no, active
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Does calcium activates PDH phophatase?
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yes
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When does PDH need to be active?
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when there's a need to make ATP from glucose
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What is elevated when PDH is active?
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pyruvate, ADP, NAD+, CoA
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What inhibits PDH kinase?
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pyruvate, ADP, NAD+, CoA
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When is PDH inactive?
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when pyruvate needs to be used for gluconeogenesis (making glucose)
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What is low when PDH is active?
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NADH
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is catabolism oxidation of fuels?
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yes
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What's the production of starting materials for synthetic reactions called?
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anabolism
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What is the overall charge and delta G for the TCA cycle?
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negative and the reaction is favorable
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What's the total kcal/mol does NADH provide (TCA clycle)?
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159 kcal/mol
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What's the total of high energy phosphate bonds produced (TCA cycle)?
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12
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How many ATPs does NADH make?
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3 ATPs per NADH
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How many ATPs does 1 FADH2 make?
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2 ATPs
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What enzyme is found in the inner mitochondrial membrane and is part of Complex II of the electron transport chain?
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succinate dehydrogenase
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What is inhibited by increasing of ATP, NADH, citrate, AND succinyl CoA?
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citrate synhase
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Where does the most important regulation of the TCA cycle come from?
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availability of acetyl CoA and oxaloacetate
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What regulates TCA cycle?
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citrate synthase, isocitrate dehydrogenase (main one), AND alpha-ketoglutarate dehydrogenase
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What activates isocitrate dehydrogenase?
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calcium
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What inhibits isocitrate dehydrogenase?
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NADH
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What activates alpha-ketoglutarate dehydrogenase?
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calcium
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What inhibits alpha-ketoglutarate dehydrogenase?
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ATP, NADH, and succinyl CoA
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Is ketoglutarate dehydrogenase regulated by phosphorylation?
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No
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What increases PDH activity (activates the phosphatase)?
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calcium
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What's the product of the anaplerotic pathway?
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production of oxaloacetate from pyruvate by pyruvate carboxylase
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What is the cofactor of the anaplerotic pathway?
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Biotin (to add carbon)
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Why is important for efflux of TCA cycle intermediates (removed)?
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this result in a decrease in oxaloacetate regeneration
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