Biochemistry : Reactants and Products of Glycolysis

Study concepts, example questions & explanations for Biochemistry

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Example Questions

Example Question #11 : Reactants And Products Of Glycolysis

Which process involved in cellular respiration does not yield any high energy phosphate bonds?

Possible Answers:

Electron transport chain/ATP synthase

Krebs cycle

Glycolysis

All of these produce new high energy phosphate bonds

Pyruvate dehydrogenase complex

Correct answer:

Pyruvate dehydrogenase complex

Explanation:

Glycolysis has a net yield of 2 ATP per glucose molecules. The Krebs cycle produces 2 GTP molecules per glucose. The electron transport chain and ATP synthase are the main producers of ATP in cellular respiration. The pyruvate dehydrogenase complex, however, does not yield any ATP (or any other nucleoside phosphates). It simply produces acetyl-CoA from pyruvate, releasing one molecule of carbon dioxide per pyruvate.

Example Question #11 : Reactants And Products Of Glycolysis

What enzymes in the glycolysis pathway in the liver catalyze irreversible reactions?

Possible Answers:

Glucokinase, phosphoglycerate kinase, mutase

Isomerase, aldolase, mutase

Glucokinase, pyruvate kinase, enolase

Glucokinase, phosphofructokinase-1, pyruvate kinase

Aldolase, phosphofructokinase-1, mutase

Correct answer:

Glucokinase, phosphofructokinase-1, pyruvate kinase

Explanation:

In the liver, glucokinase irreversibly converts glucose in the cell to glucose-6-phosphate. Phosphofructose kinase-1 irreversibly converts fructose-6-phosphate to fructose-1,6-bisphosphate. Pyruvate kinase converts phosphoenolpyruvate to pyruvate. All the other enzymes listed catalyze reversible glycolysis reactions.

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