Which of the following is the correct sequence of enzyme-catalyzed reactions from glucose to pyruvate in glycolysis?

Explanation

## The Ten Reactions of Glycolysis: Correct Sequence **Key Point:** Glycolysis proceeds through 10 sequential enzyme-catalyzed reactions. The correct order must be memorized for NEET PG. ### The Complete Glycolytic Pathway ```mermaid flowchart TD A["Glucose"]:::outcome --> B["Hexokinase"]:::action B --> C["Glucose-6-phosphate"]:::outcome C --> D["Phosphoglucose isomerase"]:::action D --> E["Fructose-6-phosphate"]:::outcome E --> F["Phosphofructokinase-1"]:::action F --> G["Fructose-1,6-bisphosphate"]:::outcome G --> H["Aldolase"]:::action H --> I["DHAP + G3P"]:::outcome I --> J["Triose phosphate isomerase"]:::action J --> K["2 × G3P"]:::outcome K --> L["Glyceraldehyde-3-phosphate dehydrogenase"]:::action L --> M["1,3-bisphosphoglycerate"]:::outcome M --> N["Phosphoglycerate kinase"]:::action N --> O["3-phosphoglycerate"]:::outcome O --> P["Phosphoglycerate mutase"]:::action P --> Q["2-phosphoglycerate"]:::outcome Q --> R["Enolase"]:::action R --> S["Phosphoenolpyruvate"]:::outcome S --> T["Pyruvate kinase"]:::action T --> U["Pyruvate"]:::outcome ``` **High-Yield:** The sequence is: **Hexokinase → PGI → PFK → Aldolase → TPI → GAPDH → PGK → PGM → Enolase → PK** **Mnemonic:** **"Help, Please Find Another Good Glucose Provider!"** — Hexokinase, Phosphoglucose isomerase, Phosphofructokinase, Aldolase, Glyceraldehyde-3-phosphate dehydrogenase, (and the remaining enzymes follow in order). ### Critical Checkpoints - **Step 1:** Hexokinase acts FIRST (glucose → G6P) - **Step 2:** Phosphoglucose isomerase converts G6P → F6P - **Step 3:** Phosphofructokinase acts on F6P (rate-limiting step) - **Step 4:** Aldolase cleaves F-1,6-BP into DHAP and G3P - **Step 5:** Triose phosphate isomerase converts DHAP → G3P (so both trioses proceed as G3P) - **Steps 6–10:** The remaining enzymes complete the pathway to pyruvate **Warning:** A common trap is confusing the order of phosphoglucose isomerase and phosphofructokinase. PGI MUST come before PFK.