Glycolysis pathway diagram with labeled steps and placeholders for enzyme names and compound structures.

Based on the provided image, which depicts the glycolysis pathway, we need to fill in the enzyme names (in boxes J, Q, M, C, Y) and the compound structures (in circles G, K, I, E, A, J, H, O, D, F, L).

Since you mentioned "choose from a-z" for enzymes and "A-R" for compounds (but these lists are not visible in the image), I will provide the correct biochemical names for each box and circle based on standard glycolysis knowledge. You can then match them to the corresponding letters on your next page.

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✔ Enzymes (Boxes):

- Box J (Step 1: Glucose → Glucose-6-phosphate)
→ Hexokinase (or Glucokinase in liver)
*Catalyzes the phosphorylation of glucose using ATP.*

- Box Q (Step 2: Glucose-6-phosphate ⇌ Fructose-6-phosphate)
→ Phosphoglucose isomerase
*Converts the aldose (glucose-6-P) to the ketose (fructose-6-P).*

- Box M (Step 3: Fructose-6-phosphate → Fructose-1,6-bisphosphate)
→ Phosphofructokinase-1 (PFK-1)
*Key regulatory enzyme; adds second phosphate group using ATP.*

- Box C (Step 4: Fructose-1,6-bisphosphate ⇌ DHAP + G3P)
→ Aldolase
*Splits the 6-carbon sugar into two 3-carbon molecules: dihydroxyacetone phosphate (DHAP) and glyceraldehyde-3-phosphate (G3P).*

- Box Y (Step 5: DHAP ⇌ G3P)
→ Triose phosphate isomerase (TPI)
*Converts DHAP to G3P so both 3-carbon units can proceed identically through the rest of glycolysis.*

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✔ Compounds (Circles):

- Circle G (Glucose)
→ Structure: Aldohexose with 6 carbons, typically shown as a ring or open-chain form with aldehyde at C1.

- Circle K (Glucose-6-phosphate)
→ Structure: Glucose with a phosphate group esterified to the C6 hydroxyl.

- Circle I (Fructose-6-phosphate)
→ Structure: Ketohexose with phosphate at C6.

- Circle E (Fructose-1,6-bisphosphate)
→ Structure: Fructose with phosphates at C1 and C6.

- Circle A (Glyceraldehyde-3-phosphate)
→ Structure: 3-carbon aldose phosphate (aldehyde at C1, phosphate at C3).

- Circle J (Dihydroxyacetone phosphate)
→ Structure: 3-carbon ketose phosphate (ketone at C2, phosphate at C3).

- Circle H (1,3-Bisphosphoglycerate)
→ Structure: 3-carbon carboxylic acid with high-energy acyl phosphate at C1 and regular phosphate at C3.

- Circle O (3-Phosphoglycerate)
→ Structure: 3-carbon carboxylic acid with phosphate at C3.

- Circle D (2-Phosphoglycerate)
→ Structure: 3-carbon carboxylic acid with phosphate at C2.

- Circle F (Phosphoenolpyruvate, PEP)
→ Structure: 3-carbon enol with phosphate at C2 (high-energy phosphate bond).

- Circle L (Pyruvate)
→ Structure: 3-carbon α-keto acid (CH₃-C(O)-COO⁻).

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🧪 Summary Table:

| Box/Circle | Label | Enzyme / Compound Name |
|------------|-------|---------------------------------------------|
| Box | J | Hexokinase |
| Box | Q | Phosphoglucose isomerase |
| Box | M | Phosphofructokinase-1 (PFK-1) |
| Box | C | Aldolase |
| Box | Y | Triose phosphate isomerase (TPI) |
| Circle | G | Glucose |
| Circle | K | Glucose-6-phosphate |
| Circle | I | Fructose-6-phosphate |
| Circle | E | Fructose-1,6-bisphosphate |
| Circle | A | Glyceraldehyde-3-phosphate |
| Circle | J | Dihydroxyacetone phosphate |
| Circle | H | 1,3-Bisphosphoglycerate |
| Circle | O | 3-Phosphoglycerate |
| Circle | D | 2-Phosphoglycerate |
| Circle | F | Phosphoenolpyruvate (PEP) |
| Circle | L | Pyruvate |

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💡 Notes:

- All reactions shown are part of glycolysis, the metabolic pathway that breaks down one molecule of glucose into two molecules of pyruvate.
- Steps 1–3 are the “investment phase” (consumes 2 ATP).
- Steps 4–10 are the “payoff phase” (produces 4 ATP and 2 NADH per glucose).
- The enzyme names and compound structures are universally accepted in biochemistry.

If you have the list of letters (a-z for enzymes, A-R for compounds) from the “next page,” please provide it, and I’ll map these answers to the correct letters for you!

Let me know if you’d like a diagram with labels or explanations of energy changes!