*2000 Metabolism Of Carbohydrates MCQ's* How many can you answer correctly ? *Send us your preferred topic to work on, tell us the type of questions you need, and we will get it done.* Join here: https://chat.whatsapp.com/FNGzlrYduf65yXdRcs8ZR4 1. What role does OAA play in the citric acid cycle? a. It is consumed permanently b. It acts catalytically c. It is the final product d. It accumulates in the cycle Answer: b 2. What does OAA combine with to repeat the cycle? a. Pyruvate b. Fumarate c. Acetyl-CoA d. Succinyl-CoA Answer: c 3. What is noted about the equilibrium of the reaction producing OAA? a. It strongly favors OAA b. It strongly favors L-malate c. It is neutral d. It is inhibited by ATP Answer: b 4. Despite equilibrium favoring malate, why does OAA form? a. Malate is degraded b. NADH is supplied continuously c. OAA and NADH/FADH2 are continuously removed d. OAA is converted to citrate immediately Answer: c 5. How many ATPs are produced from the oxidation of two NADH molecules through ETC? a. 4 ATP b. 2 ATP c. 6 ATP d. 3 ATP Answer: c 6. How many B vitamins are essential for the TCA cycle? a. Four b. Six c. Three d. Five Answer: d 7. In what form is riboflavin involved in the TCA cycle? a. Thiamine pyrophosphate b. Flavin adenine dinucleotide (FAD) c. Nicotinamide mononucleotide d. Biotin Answer: b 8. Which enzyme uses FAD as a cofactor? a. Aconitase b. Isocitrate dehydrogenase c. Succinate dehydrogenase d. Malate dehydrogenase Answer: c 9. What is the functional form of niacin in the TCA cycle? a. NADPH b. NAD c. FMN d. CoA Answer: b 10. Which enzymes use NAD as an electron acceptor in the TCA cycle? a. Isocitrate dehydrogenase, α-ketoglutarate dehydrogenase, malate dehydrogenase b. Succinate dehydrogenase only c. Pyruvate kinase and enolase d. Aconitase and citrate synthase Answer: a 11. Thiamine is required in what form for the TCA cycle? a. Thiamine monophosphate b. Thiamine pyrophosphate (TPP) c. Thiamine sulfate d. Thiamine chloride Answer: b 12. Which reaction in the TCA cycle requires TPP? a. Conversion of citrate to isocitrate b. Decarboxylation in α-ketoglutarate dehydrogenase reaction c. Formation of malate d. Formation of fumarate Answer: b 13. Which vitamin derivative functions as a coenzyme in α-ketoglutarate dehydrogenase reaction along with TPP? a. Vitamin B6 b. Lipoic acid c. Biotin d. Ascorbic acid Answer: b 14. Pantothenic acid contributes to which cofactor in the TCA cycle? a. NAD+ b. Coenzyme A c. FAD d. FMN Answer: b 15. Why is the TCA cycle called amphibolic? a. It produces water b. It includes both anabolic and catabolic functions c. It takes place in the cytosol d. It is not regulated Answer: b 16. What is the catabolic role of the TCA cycle? a. Conversion of glucose to glycogen b. Oxidation of acetyl-CoA to produce CO2, H2O, and ATP c. Synthesis of amino acids d. Lipid biosynthesis Answer: b 17. What describes the anabolic role of the TCA cycle? a. Synthesis of ATP only b. Formation of bile acids c. Use of intermediates for biosynthesis d. Degradation of carbohydrates Answer: c 18. Which process uses TCA cycle intermediates for synthesis of nonessential amino acids? a. Decarboxylation b. Transamination c. Beta oxidation d. Hydrolysis Answer: b 19. Which compounds are produced by transamination reactions in the TCA cycle? a. Glucose and fatty acids b. Ketoacids: PA, OAA, α-ketoglutarate c. Acetyl-CoA and citrate d. Succinyl-CoA and fumarate Answer: b 20. Which amino acid gives rise to PA by transamination? a. Glutamate b. Alanine c. Aspartate d. Arginine Answer: b 21. Which amino acid gives rise to OAA by transamination? a. Alanine b. Aspartate c. Glutamate d. Glycine Answer: b 22. Which amino acid gives rise to α-ketoglutarate by transamination? a. Alanine b. Glycine c. Glutamate d. Valine Answer: c 23. What does the reversibility of transamination reactions in the TCA cycle enable? a. Beta oxidation b. Synthesis of nonessential amino acids c. Production of essential vitamins d. Hydrolysis of proteins Answer: b 24. What is the metabolic process in which TCA intermediates help form glucose? a. Glycolysis b. Glycogenolysis c. Gluconeogenesis d. Lipogenesis Answer: c 25. What do amino acids contribute to before entering the TCA cycle? a. ATP b. Deamination or transamination c. Oxidative phosphorylation d. Lipid oxidation Answer: b 26. Which group of amino acids form pyruvate? a. Valine, methionine, isoleucine b. Glycine, alanine, serine, cysteine, threonine, hydroxyproline, tryptophan c. Arginine, histidine, proline d. Phenylalanine, tyrosine Answer: b 27. Which amino acids form α-ketoglutarate? a. Glycine, alanine, serine b. Arginine, histidine, glutamine, proline c. Valine, methionine d. Tyrosine and threonine Answer: b 28. Which amino acids form fumarate? a. Phenylalanine and tyrosine b. Glycine and serine c. Alanine and cysteine d. Arginine and histidine Answer: a 29. Which amino acids form succinyl-CoA? a. Phenylalanine, tyrosine b. Valine, methionine, isoleucine c. Glycine, tryptophan d. Alanine, glutamate Answer: b 30. What is the starting material for fatty acid synthesis? a. Pyruvate b. Oxaloacetate c. Acetyl-CoA d. Succinyl-CoA Answer: c