Biochemistry : Reactants and Products of the Citric Acid Cycle
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Example Questions
Example Question #41 : Citric Acid Cycle
The pyruvate dehydrogenase complex creates acetyl-CoA from pyruvate. What other molecule is a product of this reaction?
Pyruvate is converted to acetyl-CoA by the pyruvate dehydrogenase complex. Carbon dioxide is released during this reaction, and in addition to this, 
Example Question #42 : Citric Acid Cycle
In what part of the cell does the pyruvate dehydrogenase complex function?
The mitochondrial intermembrane
Cytoplasm
Within the inner membrane of the mitochondria
The mitochondrial matrix
In the nucleus
The mitochondrial matrix
The pyruvate dehydrogenase complex (PDC) is preparing pyruvate for the Krebs cycle by converting it to acetyl-CoA. Because the Krebs cycle functions within the mitochondrial matrix, the PDC is also taking place there. This ensures quick and easy movement from the PDC into the Krebs cycle.
Example Question #43 : Citric Acid Cycle
Which process involved in cellular respiration produces the largest quantity of high energy electron carriers?
Pyruvate dehydrogenase complex
ATP synthase
Electron transport chain
Glycolysis
Krebs cycle
Krebs cycle
The Krebs cycle produces the most high energy electron carriers of any process involved in cellular respiration. Per glucose molecule, the Krebs cycle produces 
Example Question #44 : Citric Acid Cycle
Which of the following molecules enter the Krebs cycle directly, following glycolysis?
Pyruvate dehydrogenase
Acetyl-CoA
Ubiquinone
Pyruvate
Glucose
Acetyl-CoA
Ubiquinone is a part of the electron transport chain, and has little to do with the Krebs cycle. Glucose is broken down during glycolysis, and does not enter the Krebs cycle directly. Many students make the mistake of thinking that pyruvate enters the Krebs cycle, since it is produced in glycolysis, and the Krebs cycle follows glycolysis. However, pyruvate is first converted to acetyl-CoA by the pyruvate dehydrogenase complex in the mitochondrial matrix, and acetyl-CoA enters the Krebs cycle.
Example Question #11 : Reactants And Products Of The Citric Acid Cycle
What is the role of isocitrate dehydrogenase in the citric acid cycle of the mitochondria?
Isocitrate dehydrogenase converts alpha-ketoglutarate to isocitrate and is activated by
Isocitrate dehydrogenase converts citrate to isocitrate and is activated by
Isocitrate dehydrogenase converts citrate to isocitrate and is inhibited by
Isocitrate dehydrogenase converts citrate to alpha-ketoglutarate and is inhibited by
Isocitrate dehydrogenase converts isocitrate to alpha-ketoglutarate and is inhibited by
Isocitrate dehydrogenase converts isocitrate to alpha-ketoglutarate and is inhibited by
Isocitrate dehydrogenase activation leads to oxidative decarboxylation of isocitrate in a two step process producing alpha-ketoglutarate and 
Example Question #45 : Citric Acid Cycle
Which of the following steps within the citric acid cycle results in the production of a molecule of carbon dioxide 
The conversion of malate to oxaloacetate
The conversion of succinyl-CoA to succinate
The conversion of fumarate to malate
The conversion of isocitrate to alpha-ketoglutarate
The conversion of succinate to fumarate
The conversion of isocitrate to alpha-ketoglutarate
The only step of the citric acid cycle listed that results in the production of 
The conversion of alpha-ketoglutarate to succinyl-CoA also produces a molecule of 
None of the other answer choices listed produce 
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