Which set lists all three irreversible reactions of glycolysis?

• A Hexokinase, phosphofructokinase-1, and pyruvate kinase ✓
• B Hexokinase, glyceraldehyde-3-phosphate dehydrogenase, and pyruvate kinase
• C Phosphoglucose isomerase, phosphofructokinase-1, and pyruvate kinase
• D Hexokinase, phosphofructokinase-1, and enolase

Explanation

Glycolysis has three irreversible, regulated steps: phosphorylation of glucose by hexokinase or glucokinase, phosphorylation of fructose-6-phosphate by PFK-1 (the committed step), and transfer of phosphate from phosphoenolpyruvate to ADP by pyruvate kinase. Each must be bypassed by a separate gluconeogenic enzyme. Glyceraldehyde-3-phosphate dehydrogenase and enolase catalyze freely reversible reactions near equilibrium, so options B and D are incorrect despite containing plausible enzyme names.

Reference: Lippincott Illustrated Reviews: Biochemistry, 8th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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