Step by step glycolysis

Step-by-Step Glycolysis Multiple Choice Exam

Stage 1: Energy Investment Phase

1. What is the enzyme responsible for catalyzing the first reaction of glycolysis, where glucose is phosphorylated to glucose-6-phosphate?
   A. Phosphofructokinase
   B. Hexokinase
   C. Glucose-6-phosphatase
   D. Pyruvate kinase
   
   

2. What type of reaction occurs during the conversion of glucose to glucose-6-phosphate?
   A. Isomerization
   B. Hydrolysis
   C. Phosphorylation
   D. Dehydration
   
   

3. Which enzyme catalyzes the conversion of glucose-6-phosphate into fructose-6-phosphate?
   A. Phosphofructokinase
   B. Glucose-6-phosphatase
   C. Phosphoglucose isomerase
   D. Aldolase
   
   

4. The reaction catalyzed by phosphoglucose isomerase is best described as:
   A. A phosphorylation reaction
   B. An isomerization reaction
   C. An oxidation-reduction reaction
   D. A hydrolysis reaction
   
   

5. Which enzyme catalyzes the second ATP-consuming step in glycolysis, converting fructose-6-phosphate into fructose-1,6-bisphosphate?
   A. Hexokinase
   B. Phosphoglucose isomerase
   C. Phosphofructokinase
   D. Aldolase
   
   

6. The phosphofructokinase reaction is:
   A. Endergonic and irreversible
   B. Exergonic and reversible
   C. Exergonic and irreversible
   D. Neither endergonic nor exergonic
   
   

7. Which enzyme catalyzes the cleavage of fructose-1,6-bisphosphate into two three-carbon molecules, glyceraldehyde-3-phosphate (G3P) and dihydroxyacetone phosphate (DHAP)?
   A. Aldolase
   B. Triose phosphate isomerase
   C. Phosphoglucose isomerase
   D. Phosphofructokinase
   
   

8. The enzyme triose phosphate isomerase converts:
   A. G3P to DHAP
   B. DHAP to G3P
   C. Fructose-1,6-bisphosphate to G3P
   D. 3-phosphoglycerate to 2-phosphoglycerate
   
   

Stage 2: Energy Payoff Phase

9. Which enzyme catalyzes the oxidation and phosphorylation of glyceraldehyde-3-phosphate to 1,3-bisphosphoglycerate?
   A. Glyceraldehyde-3-phosphate dehydrogenase
   B. Phosphoglycerate kinase
   C. Enolase
   D. Pyruvate kinase
   
   

10. Which molecule is reduced during the reaction catalyzed by glyceraldehyde-3-phosphate dehydrogenase?
    A. NAD+
    B. NADH
    C. ATP
    D. FAD
    
    

11. Which enzyme catalyzes the first ATP-generating step of glycolysis by converting 1,3-bisphosphoglycerate into 3-phosphoglycerate?
    A. Phosphoglycerate mutase
    B. Phosphoglycerate kinase
    C. Pyruvate kinase
    D. Aldolase
    
    

12. What type of phosphorylation occurs during the reaction catalyzed by phosphoglycerate kinase?
    A. Oxidative phosphorylation
    B. Substrate-level phosphorylation
    C. Photophosphorylation
    D. None of the above
    
    

13. Which enzyme catalyzes the rearrangement of 3-phosphoglycerate into 2-phosphoglycerate?
    A. Phosphoglycerate kinase
    B. Phosphoglycerate mutase
    C. Triose phosphate isomerase
    D. Enolase
    
    

14. The reaction catalyzed by phosphoglycerate mutase is best described as:
    A. An isomerization reaction
    B. A phosphorylation reaction
    C. A hydrolysis reaction
    D. An oxidation-reduction reaction
    
    

15. Which enzyme catalyzes the dehydration of 2-phosphoglycerate into phosphoenolpyruvate (PEP)?
    A. Enolase
    B. Phosphoglycerate mutase
    C. Pyruvate kinase
    D. Phosphoglycerate kinase
    
    

16. What is the significance of the enolase reaction in glycolysis?
    A. It produces ATP
    B. It generates NADH
    C. It forms a high-energy intermediate (PEP)
    D. It hydrolyzes ATP
    
    

17. Which enzyme catalyzes the final ATP-generating step of glycolysis, converting phosphoenolpyruvate into pyruvate?
    A. Enolase
    B. Pyruvate kinase
    C. Phosphoglycerate kinase
    D. Aldolase
    
    

18. The pyruvate kinase reaction is:
    A. Exergonic and irreversible
    B. Endergonic and reversible
    C. Neither exergonic nor endergonic
    D. Exergonic and reversible
    
    

Answer Key

1. B – Hexokinase

2. C – Phosphorylation

3. C – Phosphoglucose isomerase

4. B – Isomerization reaction

5. C – Phosphofructokinase

6. C – Exergonic and irreversible

7. A – Aldolase

8. B – DHAP to G3P

9. A – Glyceraldehyde-3-phosphate dehydrogenase

10. A – NAD+

11. B – Phosphoglycerate kinase

12. B – Substrate-level phosphorylation

13. B – Phosphoglycerate mutase

14. A – Isomerization reaction

15. A – Enolase

16. C – Forms a high-energy intermediate (PEP)

17. B – Pyruvate kinase

A – Exergonic and irreversible