Glycolysis MCQs With Answer offers B. Pharm students a focused, exam-oriented review of the glycolytic pathway, enzyme mechanisms, regulation, and clinical correlations. This concise introduction covers key topics like ATP yield, irreversible control points (hexokinase, phosphofructokinase-1, pyruvate kinase), NADH handling, substrate-level phosphorylation, and links to gluconeogenesis and the pentose phosphate pathway. High-quality, keyword-rich practice questions reinforce concepts such as isoenzymes, allosteric modulators, metabolic inhibitors, and pathological states like pyruvate kinase deficiency and the Warburg effect. Ideal for revision, competitive exams, and practical understanding, these MCQs enhance retention and application for pharmacy students. Now let’s test your knowledge with 50 MCQs on this topic.
Q1. Which enzyme catalyzes the phosphorylation of glucose to glucose-6-phosphate in glycolysis?
- Hexokinase
- Phosphofructokinase-1
- Pyruvate kinase
- Glucose-6-phosphatase
Correct Answer: Hexokinase
Q2. What is the net ATP yield per glucose molecule during anaerobic glycolysis in most cells?
- 1 ATP
- 2 ATP
- 4 ATP
- 36 ATP
Correct Answer: 2 ATP
Q3. Which glycolytic enzyme catalyzes the committed and rate-limiting step converting fructose-6-phosphate to fructose-1,6-bisphosphate?
- Hexokinase
- Phosphofructokinase-1 (PFK-1)
- Aldolase
- Enolase
Correct Answer: Phosphofructokinase-1 (PFK-1)
Q4. Which intermediate is split by aldolase into glyceraldehyde-3-phosphate and dihydroxyacetone phosphate?
- Fructose-1,6-bisphosphate
- Glucose-6-phosphate
- 3-Phosphoglycerate
- Phosphoenolpyruvate
Correct Answer: Fructose-1,6-bisphosphate
Q5. Which enzyme converts dihydroxyacetone phosphate to glyceraldehyde-3-phosphate?
- Triose phosphate isomerase
- Glyceraldehyde-3-phosphate dehydrogenase
- Aldolase
- Phosphoglucose isomerase
Correct Answer: Triose phosphate isomerase
Q6. Which step of glycolysis generates NADH?
- Conversion of 1,3-bisphosphoglycerate to 3-phosphoglycerate
- Conversion of glyceraldehyde-3-phosphate to 1,3-bisphosphoglycerate
- Conversion of phosphoenolpyruvate to pyruvate
- Conversion of fructose-6-phosphate to fructose-1,6-bisphosphate
Correct Answer: Conversion of glyceraldehyde-3-phosphate to 1,3-bisphosphoglycerate
Q7. Which enzyme catalyzes substrate-level phosphorylation producing ATP from 1,3-bisphosphoglycerate?
- Phosphoglycerate kinase
- Pyruvate kinase
- Enolase
- Hexokinase
Correct Answer: Phosphoglycerate kinase
Q8. The final step of glycolysis converting phosphoenolpyruvate to pyruvate is catalyzed by which enzyme?
- Pyruvate kinase
- Pyruvate dehydrogenase
- Lactate dehydrogenase
- Enolase
Correct Answer: Pyruvate kinase
Q9. Which cofactor is required for glyceraldehyde-3-phosphate dehydrogenase activity?
- NAD+
- NADP+
- FAD
- CoA
Correct Answer: NAD+
Q10. Where in the cell does glycolysis occur?
- Cytosol
- Mitochondrial matrix
- Endoplasmic reticulum
- Golgi apparatus
Correct Answer: Cytosol
Q11. Which molecule directly allosterically activates phosphofructokinase-1 (PFK-1)?
- ATP
- Citrate
- AMP
- Glucose-6-phosphate
Correct Answer: AMP
Q12. Which of the following is an irreversible reaction in glycolysis?
- Fructose-6-phosphate to fructose-1,6-bisphosphate
- Glyceraldehyde-3-phosphate to 1,3-bisphosphoglycerate
- 3-Phosphoglycerate to 2-phosphoglycerate
- Interconversion of DHAP and G3P
Correct Answer: Fructose-6-phosphate to fructose-1,6-bisphosphate
Q13. Glucokinase differs from hexokinase in that glucokinase:
- Has higher affinity for glucose
- Is inhibited by glucose-6-phosphate
- Is present mainly in liver and pancreas and has lower affinity
- Is ATP-independent
Correct Answer: Is present mainly in liver and pancreas and has lower affinity
Q14. Which product of glycolysis can enter the mitochondria for aerobic oxidation?
- Pyruvate
- Lactate
- Glucose-6-phosphate
- Fructose-1,6-bisphosphate
Correct Answer: Pyruvate
Q15. During anaerobic conditions in muscle, pyruvate is converted to which compound to regenerate NAD+?
- Lactate
- Ethanol
- Acetyl-CoA
- Oxaloacetate
Correct Answer: Lactate
Q16. Which enzyme converts pyruvate to lactate?
- Lactate dehydrogenase
- Pyruvate carboxylase
- Pyruvate kinase
- Alcohol dehydrogenase
Correct Answer: Lactate dehydrogenase
Q17. Which inhibitor specifically blocks enolase and is used in fluoride tubes to preserve glucose?
- Fluoride
- Arsenate
- Iodoacetate
- 2-Deoxyglucose
Correct Answer: Fluoride
Q18. Arsenate affects glycolysis by:
- Uncoupling ATP formation during the conversion of glyceraldehyde-3-phosphate
- Inhibiting phosphofructokinase-1 directly
- Blocking glucose transport into cells
- Preventing pyruvate kinase activity
Correct Answer: Uncoupling ATP formation during the conversion of glyceraldehyde-3-phosphate
Q19. 2,3-Bisphosphoglycerate in red blood cells is formed from which glycolytic intermediate?
- 1,3-Bisphosphoglycerate
- 3-Phosphoglycerate
- 2-Phosphoglycerate
- Phosphoenolpyruvate
Correct Answer: 1,3-Bisphosphoglycerate
Q20. Which enzyme is regulated by fructose 2,6-bisphosphate?
- Phosphofructokinase-1 (PFK-1)
- Hexokinase
- Pyruvate kinase
- Enolase
Correct Answer: Phosphofructokinase-1 (PFK-1)
Q21. The bifunctional enzyme that synthesizes and degrades fructose 2,6-bisphosphate is:
- PFK-2/FBPase-2
- Phosphoglucose isomerase
- Glycogen phosphorylase
- Glucose-6-phosphatase
Correct Answer: PFK-2/FBPase-2
Q22. Which isoform of pyruvate kinase is mainly found in liver and regulated by phosphorylation?
- L-type (liver) pyruvate kinase
- M-type (muscle) pyruvate kinase
- R-type pyruvate kinase
- Brain pyruvate kinase
Correct Answer: L-type (liver) pyruvate kinase
Q23. Which glycolytic intermediate is the substrate for the pentose phosphate pathway entry point?
- Glucose-6-phosphate
- Fructose-6-phosphate
- Pyruvate
- Glyceraldehyde-3-phosphate
Correct Answer: Glucose-6-phosphate
Q24. Which enzyme deficiency causes chronic hemolytic anemia due to impaired ATP generation in erythrocytes?
- Pyruvate kinase deficiency
- Hexokinase deficiency
- Lactate dehydrogenase deficiency
- Phosphoglycerate mutase deficiency
Correct Answer: Pyruvate kinase deficiency
Q25. The Warburg effect in cancer cells refers to increased glycolysis even in the presence of:
- Oxygen
- Glucose deprivation
- High AMP levels
- Low NADH
Correct Answer: Oxygen
Q26. Which enzyme catalyzes the reversible isomerization of glucose-6-phosphate to fructose-6-phosphate?
- Phosphoglucose isomerase
- Hexokinase
- Phosphofructokinase-1
- Aldolase
Correct Answer: Phosphoglucose isomerase
Q27. Which intermediate is produced immediately after the action of enolase?
- Phosphoenolpyruvate (PEP)
- 2-Phosphoglycerate
- Pyruvate
- 3-Phosphoglycerate
Correct Answer: Phosphoenolpyruvate (PEP)
Q28. Which inhibitor is a glycolytic analogue that gets phosphorylated but cannot be further metabolized, inhibiting hexokinase?
- 2-Deoxyglucose
- Arsenate
- Fluoride
- Iodoacetate
Correct Answer: 2-Deoxyglucose
Q29. Which enzyme converts 3-phosphoglycerate to 2-phosphoglycerate?
- Phosphoglycerate mutase
- Phosphoglycerate kinase
- Enolase
- Triose phosphate isomerase
Correct Answer: Phosphoglycerate mutase
Q30. Which molecule inhibits phosphofructokinase-1 as a signal of abundant energy?
- ATP
- AMP
- Fructose-2,6-bisphosphate
- ADP
Correct Answer: ATP
Q31. Which enzyme in glycolysis is inhibited by iodoacetate by modifying cysteine residues?
- Glyceraldehyde-3-phosphate dehydrogenase
- Hexokinase
- Enolase
- Pyruvate kinase
Correct Answer: Glyceraldehyde-3-phosphate dehydrogenase
Q32. Which shuttle transfers reducing equivalents from cytosolic NADH into mitochondria more efficiently in heart and liver?
- Malate-aspartate shuttle
- Glycerol-3-phosphate shuttle
- Urea shuttle
- Electron-transferring flavoprotein shuttle
Correct Answer: Malate-aspartate shuttle
Q33. Which reaction in glycolysis produces a high-energy enol phosphate bond used for ATP synthesis?
- Conversion of 2-phosphoglycerate to phosphoenolpyruvate
- Conversion of 3-phosphoglycerate to 2-phosphoglycerate
- Conversion of glyceraldehyde-3-phosphate to 1,3-bisphosphoglycerate
- Conversion of glucose to glucose-6-phosphate
Correct Answer: Conversion of 2-phosphoglycerate to phosphoenolpyruvate
Q34. Which enzyme catalyzes the reversible interconversion between 2-phosphoglycerate and phosphoenolpyruvate?
- Enolase
- Phosphoglycerate kinase
- Pyruvate kinase
- Phosphoglycerate mutase
Correct Answer: Enolase
Q35. In gluconeogenesis, which enzyme bypasses the irreversible step catalyzed by phosphofructokinase-1?
- Fructose-1,6-bisphosphatase
- Hexokinase
- Pyruvate kinase
- Aldolase
Correct Answer: Fructose-1,6-bisphosphatase
Q36. Which hormone stimulates glycolysis in adipose and muscle by increasing PFK-2 activity and fructose-2,6-bisphosphate?
- Insulin
- Glucagon
- Adrenaline (epinephrine)
- Cortisol
Correct Answer: Insulin
Q37. Which glycolytic intermediate is the precursor for serine biosynthesis?
- 3-Phosphoglycerate
- Fructose-6-phosphate
- Glyceraldehyde-3-phosphate
- Pyruvate
Correct Answer: 3-Phosphoglycerate
Q38. Which molecule allosterically activates pyruvate kinase in the liver following a high-carbohydrate meal?
- Fructose-1,6-bisphosphate
- ATP
- Alanine
- Citrate
Correct Answer: Fructose-1,6-bisphosphate
Q39. During intense exercise, high AMP levels primarily stimulate which metabolic pathway?
- Glycolysis
- Gluconeogenesis
- Fatty acid synthesis
- Cholesterol synthesis
Correct Answer: Glycolysis
Q40. Which compound is a common product of glycolysis in yeast under anaerobic conditions?
- Ethanol
- Lactate
- Acetyl-CoA
- Glycerol-3-phosphate
Correct Answer: Ethanol
Q41. Which glycolytic enzyme is subject to feed-forward activation by fructose-1,6-bisphosphate?
- Pyruvate kinase
- Hexokinase
- PFK-1
- Phosphoglycerate kinase
Correct Answer: Pyruvate kinase
Q42. Which intermediate directly donates a phosphate for the formation of ATP by pyruvate kinase?
- Phosphoenolpyruvate (PEP)
- 1,3-Bisphosphoglycerate
- 3-Phosphoglycerate
- 2-Phosphoglycerate
Correct Answer: Phosphoenolpyruvate (PEP)
Q43. Which enzyme is inhibited by high levels of citrate, linking TCA cycle status to glycolysis?
- Phosphofructokinase-1 (PFK-1)
- Hexokinase
- Enolase
- Pyruvate kinase
Correct Answer: Phosphofructokinase-1 (PFK-1)
Q44. Which glycolytic intermediate is directly converted to 2,3-bisphosphoglycerate in red blood cells?
- 1,3-Bisphosphoglycerate
- 3-Phosphoglycerate
- Phosphoenolpyruvate
- Glyceraldehyde-3-phosphate
Correct Answer: 1,3-Bisphosphoglycerate
Q45. Which metabolic fate of pyruvate occurs when mitochondria are functional and oxygen is sufficient?
- Conversion to acetyl-CoA by pyruvate dehydrogenase
- Conversion to lactate by lactate dehydrogenase
- Direct conversion to ethanol
- Conversion to oxaloacetate by lactate dehydrogenase
Correct Answer: Conversion to acetyl-CoA by pyruvate dehydrogenase
Q46. Which enzyme catalyzes formation of 3-phosphoglycerate from 1,3-bisphosphoglycerate along with ATP generation?
- Phosphoglycerate kinase
- Pyruvate kinase
- Phosphoglycerate mutase
- Enolase
Correct Answer: Phosphoglycerate kinase
Q47. The conversion of phosphoenolpyruvate to pyruvate yields how many ATP molecules per glucose overall (from both substrate-level phosphorylations)?
- 2 ATP produced at this step per glucose (total 4 in glycolysis)
- 1 ATP per glucose (total 2)
- 0 ATP
- 4 ATP per glucose (total 8)
Correct Answer: 2 ATP produced at this step per glucose (total 4 in glycolysis)
Q48. Which metabolite accumulation signals low glycolytic flux and inhibits hexokinase?
- Glucose-6-phosphate
- Fructose-1,6-bisphosphate
- Pyruvate
- Fructose-2,6-bisphosphate
Correct Answer: Glucose-6-phosphate
Q49. Which enzyme converts pyruvate to oxaloacetate, an important anaplerotic reaction for gluconeogenesis?
- Pyruvate carboxylase
- Pyruvate dehydrogenase
- Alanine transaminase
- Lactate dehydrogenase
Correct Answer: Pyruvate carboxylase
Q50. In erythrocytes, which pathway competes with glycolysis for glucose-6-phosphate when NADPH is required?
- Pentose phosphate pathway
- Citric acid cycle
- Fatty acid oxidation
- Urea cycle
Correct Answer: Pentose phosphate pathway
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