1. Which of the following is the first step of glycolysis?
A) Formation of glucose-6-phosphate
B) Conversion of glucose to glucose-6-phosphate
C) Formation of fructose-1,6-bisphosphate
D) Conversion of glucose to pyruvate
Answer: B) Conversion of glucose to glucose-6-phosphate
2. The enzyme hexokinase is involved in the conversion of glucose to which compound in glycolysis?
A) Glucose-6-phosphate
B) Fructose-1,6-bisphosphate
C) Pyruvate
D) Acetyl-CoA
Answer: A) Glucose-6-phosphate
3. The conversion of glucose to pyruvate involves how many ATP molecules?
A) 4 ATP
B) 2 ATP
C) 6 ATP
D) 1 ATP
Answer: B) 2 ATP
4. Which of the following enzymes is responsible for the conversion of glucose-6-phosphate to fructose-6-phosphate?
A) Hexokinase
B) Phosphofructokinase
C) Phosphoglucose isomerase
D) Pyruvate kinase
Answer: C) Phosphoglucose isomerase
5. In glycolysis, the formation of ATP occurs through which mechanism?
A) Substrate-level phosphorylation
B) Oxidative phosphorylation
C) Photophosphorylation
D) Proton gradient synthesis
Answer: A) Substrate-level phosphorylation
6. The enzyme phosphofructokinase (PFK) catalyzes which reaction in glycolysis?
A) Conversion of fructose-6-phosphate to fructose-1,6-bisphosphate
B) Conversion of glucose to glucose-6-phosphate
C) Conversion of phosphoenolpyruvate to pyruvate
D) Conversion of dihydroxyacetone phosphate to glyceraldehyde-3-phosphate
Answer: A) Conversion of fructose-6-phosphate to fructose-1,6-bisphosphate
7. During glycolysis, NAD+ is reduced to which molecule?
A) NADP+
B) NADH
C) ATP
D) FADH2
Answer: B) NADH
8. How many NADH molecules are produced per molecule of glucose during glycolysis?
A) 1
B) 2
C) 3
D) 4
Answer: B) 2
9. Which molecule is produced at the end of glycolysis that is crucial for both anaerobic and aerobic pathways?
A) Acetyl-CoA
B) Pyruvate
C) Lactate
D) Glycerol
Answer: B) Pyruvate
10. What is the net ATP gain from one molecule of glucose in glycolysis?
A) 2 ATP
B) 4 ATP
C) 6 ATP
D) 1 ATP
Answer: A) 2 ATP
11. The enzyme pyruvate kinase is responsible for the conversion of which molecule in glycolysis?
A) Phosphoenolpyruvate to pyruvate
B) Glucose-6-phosphate to fructose-6-phosphate
C) Glyceraldehyde-3-phosphate to 1,3-bisphosphoglycerate
D) Fructose-1,6-bisphosphate to glyceraldehyde-3-phosphate
Answer: A) Phosphoenolpyruvate to pyruvate
12. Which of the following molecules is an intermediate of glycolysis?
A) Pyruvate
B) Acetyl-CoA
C) Glucose
D) All of the above
Answer: A) Pyruvate
13. The enzyme aldolase is involved in the cleavage of which molecule during glycolysis?
A) Fructose-6-phosphate
B) Fructose-1,6-bisphosphate
C) Glucose-6-phosphate
D) Dihydroxyacetone phosphate
Answer: B) Fructose-1,6-bisphosphate
14. What is the purpose of the ATP produced in glycolysis?
A) To be used for cell maintenance and energy
B) To drive the TCA cycle
C) To synthesize proteins
D) To produce NADPH
Answer: A) To be used for cell maintenance and energy
15. Which molecule regulates the activity of phosphofructokinase in glycolysis?
A) ATP
B) NADH
C) Acetyl-CoA
D) Glucose-6-phosphate
Answer: A) ATP
16. What happens to pyruvate after glycolysis in the presence of oxygen?
A) It is converted to lactate
B) It enters the citric acid cycle
C) It is converted to ethanol
D) It is used to produce glucose
Answer: B) It enters the citric acid cycle
17. In which of the following conditions is glycolysis mainly anaerobic?
A) When oxygen is abundant
B) In muscles during intense exercise
C) In the mitochondria
D) When cells undergo oxidative phosphorylation
Answer: B) In muscles during intense exercise
18. How many ATP molecules are consumed during the energy investment phase of glycolysis?
A) 1 ATP
B) 2 ATP
C) 3 ATP
D) 4 ATP
Answer: B) 2 ATP
19. Which step in glycolysis is considered the rate-limiting step?
A) Conversion of glucose to glucose-6-phosphate
B) Conversion of fructose-6-phosphate to fructose-1,6-bisphosphate
C) Conversion of phosphoenolpyruvate to pyruvate
D) Conversion of 1,3-bisphosphoglycerate to 3-phosphoglycerate
Answer: B) Conversion of fructose-6-phosphate to fructose-1,6-bisphosphate
20. The enzyme triose phosphate isomerase converts which molecule during glycolysis?
A) Dihydroxyacetone phosphate to glyceraldehyde-3-phosphate
B) Glyceraldehyde-3-phosphate to dihydroxyacetone phosphate
C) Phosphoenolpyruvate to pyruvate
D) Fructose-6-phosphate to glucose-6-phosphate
Answer: A) Dihydroxyacetone phosphate to glyceraldehyde-3-phosphate
21. Which of the following occurs during the energy payoff phase of glycolysis?
A) ATP is consumed
B) NADH is produced
C) Glucose is split into two molecules
D) NADH is oxidized
Answer: B) NADH is produced
22. The enzyme glyceraldehyde-3-phosphate dehydrogenase catalyzes the oxidation of which molecule in glycolysis?
A) Glyceraldehyde-3-phosphate
B) Glucose-6-phosphate
C) Fructose-1,6-bisphosphate
D) Pyruvate
Answer: A) Glyceraldehyde-3-phosphate
23. The final product of glycolysis, pyruvate, can be converted into which molecule in anaerobic conditions?
A) Acetyl-CoA
B) Lactate
C) NADH
D) Glucose
Answer: B) Lactate
24. What is the main energy source for glycolysis?
A) Oxygen
B) NADH
C) Glucose
D) Fatty acids
Answer: C) Glucose
25. In glycolysis, ATP is generated by substrate-level phosphorylation. Which of the following compounds donates a phosphate group for this process?
A) Glyceraldehyde-3-phosphate
B) Phosphoenolpyruvate
C) Fructose-6-phosphate
D) Glucose-6-phosphate
Answer: B) Phosphoenolpyruvate
26. What happens to NADH produced in glycolysis?
A) It is used to produce ATP
B) It is reoxidized to NAD+ in the mitochondria
C) It is converted to NADPH
D) It enters the citric acid cycle
Answer: B) It is reoxidized to NAD+ in the mitochondria
27. Which of the following molecules inhibits the enzyme phosphofructokinase during glycolysis?
A) NAD+
B) ATP
C) Pyruvate
D) Fructose-1,6-bisphosphate
Answer: B) ATP
28. The energy produced by glycolysis is essential for which cellular activities?
A) Protein synthesis
B) DNA replication
C) ATP production for cellular processes
D) None of the above
Answer: C) ATP production for cellular processes
29. In which of the following organisms does glycolysis occur in the cytoplasm?
A) Prokaryotes
B) Eukaryotes
C) Both prokaryotes and eukaryotes
D) None of the above
Answer: C) Both prokaryotes and eukaryotes
30. Which compound is the final product of the glycolytic pathway under anaerobic conditions?
A) Ethanol
B) Acetyl-CoA
C) Pyruvate
D) Lactate
Answer: D) Lactate
