Term
| the one way link between glycolysis and cellular respiration |
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Definition
|
|
Term
| what happens to pyruvate in anaerobic conditions? |
|
Definition
| converted to lactic acid or ethanol |
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|
Term
| what happens to pyruvate in aerobic conditions |
|
Definition
| converted into acetyl coenzyme A (acetyl CoA), which enters the citric acid cycle |
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|
Term
| what happens to pyruvate when a cell's oxygen supply is insufficient? |
|
Definition
| gets converted to lactate |
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|
Term
| simplified overview of the citric acid cycle |
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Definition
|
|
Term
| pyruvate dehydrogenase complex |
|
Definition
| oxidatively decarboxylates pyruvate to form acetyl CoA |
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|
Term
| the chemical rxn of the pyruvate dehydrogenase complex |
|
Definition
| pyruvate + CoA + NAD+ --> acetyl CoA + CO2 NADH + H+ |
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Term
| where oxidative decarboxylation of pyruvate occurs |
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Definition
|
|
Term
| where citric acid cycle occurs |
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Definition
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|
Term
| the rxn E1 in the pyruvate dehydrogenase complex catalyzes |
|
Definition
| oxidative decarboxylation of pyruvate |
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|
Term
| the rxn E2 in the pyruvate dehydrogenase complex catalyzes |
|
Definition
| transfer of acetyl group to CoA |
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|
Term
| the rxn E3 in the pyruvate dehydrogenase complex catalyzes |
|
Definition
| regeneration of the oxidized form of lipoamide |
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Term
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
| the link between glycolysis and the citric acid cycle |
|
Definition
| the irreversible conversion of pyruvate into acetyl CoA |
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|
Term
| depiction of the link between glycolysis and the citric acid cycle |
|
Definition
|
|
Term
|
Definition
| function as enzymes; not permanently altered by participation in rxn |
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Term
|
Definition
| they function as substrates |
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|
Term
| the 3 steps of the conversion of pyruvate into acetyl CoA |
|
Definition
1: decarboxylation
2: oxidation
3: the transfer of the resultant acetyl group to CoA |
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|
Term
| depiction of the conversion of pyruvate into acetyl CoA |
|
Definition
|
|
Term
|
Definition
| proteins tightly associated with FAD |
|
|
Term
| what allows lipoamide to move between different active sites? |
|
Definition
|
|
Term
| depiction of the structure of the pyruvate dehydrogenase complex |
|
Definition
| [image]
-has 8 E2 (α3) trimers at the core to make a hollow cube
-the cube is surrounded by 12 E3 (αβ) dimers and 24 E1 (α2β2) |
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|
Term
| depiction of the structure of the E2 within the pyruvate dehydrogenase complex |
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Definition
[image]
contains 8 trimers |
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Term
| depiction of the domains within each E2 (α3) trimer |
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Definition
|
|
Term
| how the pyruvate dehydrogenase (PDH) complex differs in mammals |
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Definition
| the core contains another protein, E3-binding protein (E3-BP) |
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|
Term
| depiction of the reactions of the pyruvate dehydrogenase (PDH) complex |
|
Definition
|
|
Term
| what happens when the pyruvate dehydrogenase (PDH) complex is missing the E3-binding protein (E3-BP)? |
|
Definition
| the PDH complex has greatly reduced activity |
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|
Term
| how do the 3 distinct active sites of the PDH complex work in concert? |
|
Definition
| the flexible lipoamide arm of the E2 subunit carries substrate from active site to active site |
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|
Term
|
Definition
| oxidative decarboxylation of pyruvate to acetyl CoA |
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|
Term
| 2 principal fates of the carbons in acetyl CoA |
|
Definition
| 1: oxidation to CO2 by the citric acid cycle with the concomitant generation of energy
2: incorporation into lipid, because acetyl CoA is an essential precursor for lipid synthesis |
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|
Term
| simple depiction of the conversion of glucose to pyruvate to acetyl CoA to CO2 and fatty acids |
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Definition
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Term
| the key means of regulation of the PDH complex in eukaryotes |
|
Definition
| covalent modification in the form of phosphorylation |
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|
Term
| what phosphorylation does to the PDH complex |
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Definition
|
|
Term
| what dephosphorylation does to the PDH complex |
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Definition
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Term
|
Definition
| catalyzes phoisphorylation of PDH complex to deactivate it |
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|
Term
|
Definition
| catalyzes dephosphorylation of PDH complex to reactivate it |
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Term
| depiction of the regulation of the PDH complex |
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Definition
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|
Term
| PDH phosphatase is activated by... |
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Definition
|
|
Term
| depiction of PDH regulation under high energy charge |
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Definition
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|
Term
| depiction of PDH regulation under low energy charge |
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Definition
|
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Term
|
Definition
| carbon compounds capable of being oxidized |
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Term
| the function of the citric acid cycle |
|
Definition
| the harvesting of high energy electrons from carbon fuels |
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Term
| how the citric acid cycle begins |
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Definition
| the 2-carbon acetyl unit condenses with a 4-carbon oxaloacetate to yield the 6-Carbon tricarboxylic acid citrate |
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Term
| simple depiction of an overview of the citric acid cycle |
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Definition
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|
Term
| oxidative phosphorylation |
|
Definition
| forming ATP by by the transfer of electrons from NADH or FADH2 to O2 by a series of electron carriers |
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Term
|
Definition
| series of membrane proteins electrons from NADH or FADH2 floe thru to generate proton gradient |
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|
Term
| what proton gradient is used for |
|
Definition
| to generate ATP from ADP and inorganic phosphate |
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Term
| the stagers of cellular respiration |
|
Definition
1: citric acid cycle
2: oxidative phosphorylation |
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|
Term
| depiction of cellular respiration |
|
Definition
|
|
Term
| the 2 stages of the citric acid cycle |
|
Definition
1: oxidizing 2 carbon atoms to gather energy rich electrons
2: regenerating oxaloacetate and harvesting energy rich electrons |
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Term
| oxidative decarboxylation |
|
Definition
| citrate being oxidized by releasing 2 CO2 to yield a 4-carbon molecule and high transfer potential electrons captured as 2 molecules of NADH |
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|
Term
| how the citric acid cycle begins |
|
Definition
| joining of 4-Carbon oxaloacetate with the 2-carbon acetyl group acetyl CoA to form citryl CoA, which gets hydrolyzed to form citrate |
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|
Term
| depiction of the formation of citrate |
|
Definition
[image]
citrate synthase involved in both steps |
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Term
|
Definition
| catalyzes the merging of 4-carbon oxaloacetate to the 2-carbon acetyl group to form citrate |
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Term
|
Definition
| enzyme that catalyzes a synthetic rxn in which 2 subunits are joined usually without the direct participation of ATP or another nucleoside triphosphate |
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|
Term
| this powers the synthesis of citrate |
|
Definition
| the hydrolysis of the thioester in citryl CoA |
|
|
Term
| composition of mammalian citrate synthase |
|
Definition
| dimer of identical 49-kDa subunitswith a cleft present between the large and small domains of the subunits, adjacent to the subunit interface |
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|
Term
| the reason for ordered binding in citrate synthase |
|
Definition
| because oxaloacetate induces a major structural rearrangement leading to the creation of a binding site for acetyl CoA |
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|
Term
| depiction of the structure of citrate synthase |
|
Definition
|
|
Term
| how the wasteful hydrolysis of acetyl CoA is prevented |
|
Definition
| because citrate synthase is well suited for the hydrolysis of citryl CoA but not acetyl CoA |
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|
Term
| why citrate is isomerized into isocitrate |
|
Definition
| because the hydroxyl (-OH) group in citrate is not properly located in the molecuule for the oxidative decarboxylations that follow |
|
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Term
| how citrate is isomerized into isocitrate |
|
Definition
| dehydrateion, then hydration |
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Term
|
Definition
| catalyzes isomerization of citrate into isocitrate |
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|
Term
| depiction of how citrate is isomerized into isocitrate |
|
Definition
[image]
aconitase involved in both steps |
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Term
|
Definition
| catalyzes the oxidative decarboxylation of isocitrate to α-ketoglutarate |
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|
Term
| net rxn that oxidizes and decarboxylates isocitrate to α-ketoglutarate |
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Definition
| isocitrate + NAD+ --> α-ketoglutarate + CO2 + NADH |
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|
Term
| depiction of the oxidative decarboxylation of isocitrate to α-ketoglutarate |
|
Definition
[image]
catalyzed by isocitrate dehydrogenase |
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|
Term
| depiction of the oxidative decarboxylation of α-ketoglutarate |
|
Definition
|
|
Term
| α-ketoglutarate dehydrogenase complex |
|
Definition
catalyzes the oxidative decarboxylation of α-ketoglutarate
structurally similar to PDH |
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|
Term
| how the citric acid cycle produces ATP |
|
Definition
| the cleavage of the thioester of succinyl CoA is coupled with the phosphorylation of ADP |
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Term
| succinyl CoA synthetase (succinate thiokinase) |
|
Definition
| catalyzes the cleavage of the thioester of succinyl CoA that gets coupled with the phosphorylation of ADP |
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Term
| depiction of the cleavage of the thioester of succinyl CoA that gets coupled with the phosphorylation of ADP to yield ATP |
|
Definition
[image]
catalyzed by succinyl CoA synthetase (succinate thiokinase) |
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Term
| the 2 forms of succinyl CoA synthetase (succinate thiokinase) in mammals |
|
Definition
1: ADP acceptor
2: GDP acceptor |
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|
Term
| tissue where the ADP accepting version of succinyl CoA synthetase (succinate thiokinase) dominates in mammals |
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Definition
| tissues that perform lost of cellular respiration, such as skeletal and heart muscle |
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Term
| tissue where the GDP accepting version of succinyl CoA synthetase (succinate thiokinase) dominates in mammals |
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Definition
| tissues that perform lost of anabolic rxns, such as liver |
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Term
| how the GDP-requiring form of succinyl CoA synthetase (succinate thiokinase) is believed to work |
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Definition
| in reverse of the direction observed in the citric acid cycle; that is, GTP is used to power the synthesis of succinyl CoA, which is a precursor for heme synthesis |
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Term
| substrate-level phosphorylation |
|
Definition
| generation of ATP a rxn in which a high-phosphoryl-transfer-potential compound (succinyl phosphate) transfers the phosphate to ADP to generate ATP |
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Term
| types of rxns glycolysis uses to form ATP |
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Definition
| substrate-level phosphorylation rxns |
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|
Term
| depiction of the rxn mechanism of succinyl CoA synthetase |
|
Definition
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|
Term
| how oxaloacetate is regenerated |
|
Definition
| by the oxidation of succinate |
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|
Term
| depiction of the oxidation of succinate |
|
Definition
|
|
Term
| how succinate is oxidized to regenerate oxaloacetate |
|
Definition
1: oxidation
2: hydration
3: 2nd oxidation |
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|
Term
|
Definition
| catalyzes the oxidation of succinate to fumarate |
|
|
Term
| depiction of the function of succinate dehydrogenase |
|
Definition
|
|
Term
| how succinate dehydrogenase differs from other enzymes in the citric acid cycle |
|
Definition
| it is embedded in the inner mitochondrial membrane in association with the electron transport chain, which is also set in the inner mitochondrial membrane |
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Term
| the link between the citric acid cycle and ATP formation |
|
Definition
| the electron transport chain |
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Term
|
Definition
| catalyzes hydration of fumarate to form L-malate |
|
|
Term
| depiction of the function of fumarase |
|
Definition
|
|
Term
|
Definition
| catalyzes oxidation of malate to form oxaloacetate |
|
|
Term
| depiction of the function of malate dehydrogenase |
|
Definition
|
|
Term
| how the energetically unfavorable oxidation of malate is driven |
|
Definition
| driven by the use of the products; oxaloacetate by citrate synthase and NADH by the electron-transport chain |
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|
Term
| the net rxn of the citric acid cycle |
|
Definition
| acetyl CoA + 3 NAD+ + FAD + ADP + pi + 2 H2O --> 2 CO2 + 3 NADH + FADH2 + ATP + 2 H+ + CoA |
|
|
Term
| depiction of the complete citric acid cycle |
|
Definition
|
|
Term
|
Definition
| rxn products passing directly from one active site to the nest thru connecting channels |
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|
Term
| the key catabolic function of the citric acid cycle |
|
Definition
| the production of high energy electrons in the form of NADH and FADH2 |
|
|
Term
| does molecular oxygen participate directly in the citric acid cycle? |
|
Definition
|
|
Term
| why the citric acid cycle operates only under aerobic conditions |
|
Definition
| because NAD+ and FAD can be regenerated in mitochondria only by the transfer of electrons to molecular oxygen |
|
|
Term
| how NAD+ and FAD can be regenerated in mitochondria |
|
Definition
| only by the transfer of electrons to molecular oxygen |
|
|
Term
| why glycolysis can proceed under anaerobic conditions |
|
Definition
| because NAD+ is regenerated in the conversion of pyruvate into lactate or ethanol |
|
|
Term
| depiction of the control of the citric acid cycle |
|
Definition
|
|
Term
| the primary control points to control the rate of the citric acid cycle |
|
Definition
-isocitrate dehydrogenase
-α-ketoglutarate dehydrogenase |
|
|
Term
| the citric acid cycle is regulated primarily by the concentrations of... |
|
Definition
|
|
Term
| something succinyl CoA from the citric acid cycle is used to make |
|
Definition
| the heme groups of hemoglobin and myoglobin |
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|
Term
| something α-ketoglutarate from the citric acid cycle is used to make |
|
Definition
|
|
Term
| something oxaloacetate from the citric acid cycle is used to make |
|
Definition
|
|
Term
| depiction of the biosynthetic roles of the citric acid cycle |
|
Definition
|
|
Term
| when the citric acid cycle creates intermediates for biosynthesis |
|
Definition
| when the energy needs of the cell are met |
|
|
Term
| how are citric acid cycle intermediates replenished when they are drawn out for biosynthesis |
|
Definition
| conversion of pyruvate to oxaloacetate |
|
|
Term
|
Definition
| catalyzes the conversion of pyruvate to oxaloacetate |
|
|
Term
| rxn that converts pyruvate to oxaloacetate |
|
Definition
| pyruvate + CO?2 + ATP + H2O --> oxaloacetate + ADP + Pi + 2 H+ |
|
|
Term
| depiction of pyruvate carboxylase replenishing the citric acid cycle |
|
Definition
|
|
Term
| when pyruvate carboxylase is active |
|
Definition
| only in the presence of acetyl CoA |
|
|
Term
| what happens to oxaloacetate when the energy charge is high? |
|
Definition
| oxaloacetate gets converted into glucose |
|
|
Term
| what happens to oxaloacetate when the energy charge is low? |
|
Definition
| oxaloacetate replenishes the citric acid cycle |
|
|
Term
|
Definition
| rxn that leads to the net synthesis, or replenishment, of pathway components |
|
|
Term
| example of an anaplerotic rxn |
|
Definition
| synthesis of oxaloacetate by the carboxylation of pyruvate |
|
|
Term
| the fate of acetyl CoA that enters the citric acid cycle |
|
Definition
|
|
Term
| what the glyoxylate cycle enables plants and bacteria to do |
|
Definition
| convert fats into carbohydrates |
|
|
Term
| some ways the glyoxylate cycle differs from the citric acid cycle |
|
Definition
-bypasses the 2 decarboxylation steps of the cycle
-2 acetyl CoA's enter the cycle instead of just 1 |
|
|
Term
|
Definition
| cleaves isocitrate into succinate and glyoxylate |
|
|
Term
|
Definition
| catalyzes the condensation of acetyl CoA with glyoxylate to form malate |
|
|
Term
| depiction of the glyoxylate pathway |
|
Definition
|
|
Term
|
Definition
| organelles in plants where the glyoxylate pathway takes place |
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|
