Choose the correct answer from the options given below :

• (1) (A)-(IV), (B)-(III), (C)-(II), (D)-(I)
• (2) (A)-(I), (B)-(IV), (C)-(II), (D)-(I)
• (3) (A)-(I), (B)-(II), (C)-(III), (D)-(IV)
• (4) (A)-(IV), (B)-(III), (C)-(I), (D)-(II)

  Hexokinase initiates glycolysis by phosphorylating glucose, while pyruvate kinase, aldolase, and enolase catalyze key later steps in the pathway. The correct matching identifies their specific substrate-product reactions.

  Enzyme Functions

  Glycolysis converts glucose to pyruvate through 10 enzymatic steps, with each enzyme listed performing a distinct reaction.

  • Hexokinase (A): Catalyzes Glucose → Glucose-6-phosphate (III), the first committed step using ATP.

  • Pyruvate kinase (B): Converts Phosphoenol pyruvate (PEP) → Pyruvate (IV), generating ATP in the final step.​

  • Aldolase (C): Cleaves Fructose 1,6-bisphosphate → Glyceraldehyde 3-phosphate and DHAP (II).​

  • Enolase (D): Dehydrates 2–phosphoglycerate → phosphoenol pyruvate (PEP) (I).​

  Option Analysis

  • Option (1): (A)-(IV), (B)-(III), (C)-(II), (D)-(I) mismatches all; hexokinase does not produce pyruvate.​

  • Option (2): (A)-(I), (B)-(IV), (C)-(II), (D)-(I) wrong on A and duplicate D; enolase is I, not hexokinase.​

  • Option (3): (A)-(I), (B)-(II), (C)-(III), (D)-(IV) incorrect; pyruvate kinase is IV, aldolase is II.​

  • Option (4): (A)-(IV), (B)-(III), (C)-(I), (D)-(II) fails; pyruvate kinase does not cleave fructose bisphosphate.​

  Correct answer: (2) (A)-(III), (B)-(IV), (C)-(II), (D)-(I).

  In glycolysis enzymes matching questions, identifying reactions like Hexokinase (Glucose → Glucose-6-phosphate), Pyruvate kinase (PEP → Pyruvate), Aldolase (Fructose 1,6-bisphosphate → G3P + DHAP), and Enolase (2-PG → PEP) is crucial for exams. This guide breaks down the pathway for precise matching.​

  Glycolysis Pathway Overview

  Glycolysis breaks glucose into two pyruvates, netting 2 ATP and 2 NADH. Key enzymes commit or regulate flux.

  Correct Enzyme-Reaction Matches

  Enzyme (List I)	Reaction (List II)	Step Number
  (A) Hexokinase	(III) Glucose → Glucose-6-phosphate	1
  (B) Pyruvate kinase	(IV) PEP → Pyruvate	10 ​
  (C) Aldolase	(II) F-1,6-BP → G3P + DHAP	4 ​
  (D) Enolase	(I) 2-PG → PEP	9 ​

  Why Options Fail

  Option 1 swaps early/late steps; Option 2 duplicates I; Option 3 misassigns kinase/aldolase; Option 4 ignores aldolase cleavage. Only option 2 fits perfectly.​

  For GATE Life Sciences prep, memorize these irreversible steps: hexokinase traps glucose, aldolase splits C6 to C3, enolase creates high-energy PEP, pyruvate kinase yields ATP.​