Practice Quiz-2 PDF

1. **What does DNA stand for?** A) Deoxyribonucleic Acid B) Ribonucleic Acid C) Dextrorotatory Acid D) Ribosomal DNA **Answer: Deoxyribonucleic Acid** 2. **What is the primary function of RNA?** A) Stores genetic information B) Transmits signals C) Helps build proteins D) Repairs...

1. **What does DNA stand for?** A) Deoxyribonucleic Acid B) Ribonucleic Acid C) Dextrorotatory Acid D) Ribosomal DNA **Answer: Deoxyribonucleic Acid** 2. **What is the primary function of RNA?** A) Stores genetic information B) Transmits signals C) Helps build proteins D) Repairs DNA **Answer: Helps build proteins** 3. **Which of the following is a difference between DNA and RNA?** A) DNA contains uracil, RNA contains thymine B) DNA is single-stranded, RNA is double-stranded C) RNA contains uracil, DNA contains thymine D) RNA is located in the nucleus, DNA is found in the cytoplasm **Answer: RNA contains uracil, DNA contains thymine** 4. **Which of the following is a type of RNA that is involved in protein synthesis?** A) mRNA B) tRNA C) rRNA D) All of the above **Answer: All of the above** 5. **What type of bond holds the two strands of DNA together in its double-helix structure?** A) Covalent bonds B) Hydrogen bonds C) Ionic bonds D) Peptide bonds **Answer: Hydrogen bonds** 6. **Which enzyme is responsible for unwinding the DNA during replication?** A) DNA polymerase B) Ligase C) Helicase D) Primase **Answer: Helicase** 7. **In the process of transcription, what is synthesized from a DNA template?** A) Protein B) mRNA C) tRNA  D) DNA **Answer: mRNA** 8. **What is the main role of ribosomal RNA (rRNA)?** A) Carry genetic information from the DNA to the ribosome B) Catalyze protein synthesis at the ribosome C) Transfer amino acids to the ribosome D) Protect DNA from damage **Answer: Catalyze protein synthesis at the ribosome** 9. **Which of the following is a type of mutation where one base is replaced by another?** A) Frameshift mutation B) Substitution mutation C) Deletion mutation D) Insertion mutation **Answer: Substitution mutation** 10. **Which molecule acts as the "energy currency" of the cell?** A) DNA B) RNA C) ATP D) NADH **Answer: ATP** 11. **Which of the following is the simplest form of carbohydrates?** A) Monosaccharides B) Disaccharides C) Polysaccharides D) Oligosaccharides **Answer: Monosaccharides** 12. **Which monosaccharide is known as blood sugar?** A) Fructose B) Glucose C) Galactose D) Ribose **Answer: Glucose** 13. **What type of bond links monosaccharides to form disaccharides?** A) Glycosidic bond B) Hydrogen bond C) Ionic bond D) Peptide bond **Answer: Glycosidic bond** 14. **Which disaccharide is composed of glucose and fructose?** A) Maltose  B) Lactose C) Sucrose D) Trehalose **Answer: Sucrose** 15. **What is the primary function of glycogen in animals?** A) Energy storage B) Structural support C) Protein synthesis D) Enzyme activation **Answer: Energy storage** 16. **Which carbohydrate is indigestible by humans but important for digestive health?** A) Starch B) Cellulose C) Glycogen D) Lactose **Answer: Cellulose** 17. **Which enzyme is responsible for breaking down starch into maltose?** A) Amylase B) Lipase C) Protease D) Lactase **Answer: Amylase** 18. **Which of the following is a type of protein metabolism?** A) Protein synthesis B) Protein digestion C) Protein turnover D) All of the above **Answer: All of the above** 19. **What is the primary role of amino acids in the body?** A) To store energy B) To form enzymes and hormones C) To provide structural support to cells D) To form starch **Answer: To form enzymes and hormones** 20. **Which process is responsible for removing the amino group from amino acids?** A) Transamination B) Hydrolysis C) Oxidative deamination D) Glycosylation **Answer: Transamination** 21. **Which molecule is produced during oxidative deamination of glutamate?** A) Pyruvate B) Acetyl-CoA C) Ammonia D) Urea **Answer: Ammonia** 22. **Which metabolic pathway generates the most ATP per glucose molecule?** A) Glycolysis B) Citric acid cycle C) Electron transport chain D) Fermentation **Answer: Electron transport chain** 23. **Where does β-oxidation of fatty acids primarily occur?** A) Cytoplasm B) Mitochondria C) Nucleus D) Ribosome **Answer: Mitochondria** 24. **Which enzyme is required for the activation of fatty acids before they enter β-oxidation?** A) Acetyl-CoA synthetase B) Carnitine acyltransferase C) Coenzyme A D) Lipase **Answer: Acetyl-CoA synthetase** 25. **What is the final product of one round of β-oxidation of fatty acids?** A) Acetyl-CoA B) NADH C) FADH₂ D) Pyruvate **Answer: Acetyl-CoA** 26. **Which of the following is an essential amino acid?** A) Alanine B) Glutamate C) Leucine D) Glycine **Answer: Leucine** 27. **What is the primary role of NAD⁺ in metabolism?** A) To act as an energy carrier by accepting electrons B) To provide energy for protein synthesis C) To break down carbohydrates into glucose D) To transport fatty acids into the mitochondria  **Answer: To act as an energy carrier by accepting electrons** 28. **Which of the following is true about the citric acid cycle?** A) It occurs in the cytoplasm B) It produces glucose from pyruvate C) It generates ATP, NADH, and FADH₂ D) It is also known as glycolysis **Answer: It generates ATP, NADH, and FADH₂** 29. **Which type of fatty acid is metabolized through β-oxidation?** A) Saturated fatty acids B) Unsaturated fatty acids C) Both saturated and unsaturated fatty acids D) Both fatty acids and carbohydrates **Answer: Both saturated and unsaturated fatty acids** 30. **Which molecule is produced in the last step of the citric acid cycle?** A) Acetyl-CoA B) Oxaloacetate C) Malate D) CO₂ **Answer: Oxaloacetate** 31. **What is the primary function of lipoproteins?** A) To store glucose B) To transport lipids in the bloodstream C) To break down fats D) To synthesize fatty acids **Answer: To transport lipids in the bloodstream** 32. **Which lipoprotein is often referred to as "bad cholesterol"?** A) HDL B) LDL C) VLDL D) Chylomicrons **Answer: LDL** 33. **Which molecule is a precursor for fatty acid synthesis?** A) Acetyl-CoA B) NADH C) Glucose D) Pyruvate **Answer: Acetyl-CoA** 34. **What is the primary energy source for cells during prolonged fasting?** A) Glucose B) Fatty acids C) Amino acids  D) Glycogen **Answer: Fatty acids** 35. **What is the first molecule formed during glycolysis?** A) Glucose-6-phosphate B) Fructose-6-phosphate C) Pyruvate D) Acetyl-CoA **Answer: Glucose-6-phosphate** 36. **Which molecule does glucose get converted into during glycolysis?** A) Acetyl-CoA B) Pyruvate C) Glucose-6-phosphate D) Lactic acid **Answer: Pyruvate** 37. **In what form are most fats stored in the body?** A) Triglycerides B) Phospholipids C) Cholesterol D) Fatty acids **Answer: Triglycerides** 38. **What is the main source of energy during the first 30 minutes of exercise?** A) Glycogen B) Fatty acids C) ATP D) Glucose **Answer: Glycogen** 39. **Which molecule is the final electron acceptor in the electron transport chain?** A) NADH B) FADH2 C) Oxygen D) Water **Answer: Oxygen** 40. **Where does the citric acid cycle (Krebs cycle) take place?** A) Cytoplasm B) Mitochondria C) Endoplasmic reticulum D) Nucleus **Answer: Mitochondria** 41. **Which of the following metabolic processes is responsible for synthesizing glycogen?**  A) Glycogenesis B) Glycolysis C) Gluconeogenesis D) Glycogenolysis **Answer: Glycogenesis** 42. **What is the main purpose of gluconeogenesis?** A) To break down glucose into pyruvate B) To produce glucose from non-carbohydrate precursors C) To store glucose as glycogen D) To generate ATP **Answer: To produce glucose from non-carbohydrate precursors** 43. **Which molecule is required for the transport of fatty acids into mitochondria for β-oxidation?** A) ATP B) Carnitine C) Coenzyme A D) Acetyl-CoA **Answer: Carnitine** 44. **Which of the following processes generates the most ATP per glucose molecule?** A) Glycolysis B) Citric acid cycle C) Electron transport chain D) Fermentation **Answer: Electron transport chain** 45. **Which molecule is produced in the citric acid cycle and is used in the electron transport chain?** A) Glucose B) Pyruvate C) NADH D) Lactate **Answer: NADH** 46. **What is the major role of coenzyme A in metabolism?** A) To transfer electrons in the electron transport chain B) To activate fatty acids for oxidation C) To transfer amino groups in protein metabolism D) To regulate gene expression **Answer: To activate fatty acids for oxidation** 47. **Where do the majority of ATP molecules come from in cellular respiration?** A) Glycolysis B) Citric acid cycle  C) Electron transport chain D) Fermentation **Answer: Electron transport chain** 48. **What molecule is required to form ATP in cellular respiration?** A) Oxygen B) NADH C) Glucose D) ADP and inorganic phosphate **Answer: ADP and inorganic phosphate** 49. **Which metabolic process occurs in the mitochondria and produces the most ATP per glucose molecule?** A) Glycolysis B) Citric acid cycle C) Electron transport chain D) Fermentation **Answer: Electron transport chain** 50. **Which molecule is the end product of anaerobic glycolysis?** A) Lactic acid B) Glucose C) Acetyl-CoA D) NADH **Answer: Lactic acid** 51. **What molecule is produced in the final step of the electron transport chain?** A) ATP B) Water C) NADH D) Glucose **Answer: Water** 52. **Which molecule is produced by the liver during fatty acid oxidation and used by the brain during fasting?** A) Glucose B) Ketone bodies C) Acetyl-CoA D) ATP **Answer: Ketone bodies** 53. **Where does gluconeogenesis primarily occur?** A) Cytoplasm B) Mitochondria C) Liver D) Muscle **Answer: Liver** 54. **What is the main energy source for muscles during prolonged exercise?** A) Glucose B) Fatty acids C) Amino acids D) Glycogen **Answer: Fatty acids** 55. **What is the final electron acceptor in the electron transport chain?** A) NADH B) FADH₂ C) Oxygen D) Water **Answer: Oxygen** 56. **What is the product of the enzyme lipase?** A) Glucose B) Fatty acids C) Triglycerides D) Cholesterol **Answer: Fatty acids** 57. **Which molecule is required to form ATP in cellular respiration?** A) Oxygen B) NADH C) Glucose D) ADP and inorganic phosphate **Answer: ADP and inorganic phosphate** 58. **Which metabolic process generates the most ATP per glucose molecule?** A) Glycolysis B) Citric acid cycle C) Electron transport chain D) Fermentation **Answer: Electron transport chain** 59. **Which molecule is produced during the conversion of pyruvate to acetyl-CoA?** A) NADH B) ATP C) FADH₂ D) Acetyl-CoA **Answer: NADH** 60. **What is the major role of coenzyme A in metabolism?** A) To transfer electrons in the electron transport chain B) To activate fatty acids for oxidation C) To transfer amino groups in protein metabolism D) To regulate gene expression **Answer: To activate fatty acids for oxidation** 61. **What is the first molecule formed during glycolysis?** A) Glucose-6-phosphate B) Fructose-6-phosphate C) Pyruvate D) Acetyl-CoA **Answer: Glucose-6-phosphate** 62. **Which molecule does glucose get converted into during glycolysis?** A) Acetyl-CoA B) Pyruvate C) Glucose-6-phosphate D) Lactic acid **Answer: Pyruvate** 63. **What is the product of anaerobic glycolysis?** A) Pyruvate B) Acetyl-CoA C) NADH D) Lactic acid **Answer: Lactic acid** 64. **What is the immediate source of energy for muscles during exercise?** A) Glycogen B) Fatty acids C) Amino acids D) Glucose **Answer: Glycogen** 65. **Which enzyme catalyzes the rate-limiting step of the citric acid cycle?** A) Citrate synthase B) Isocitrate dehydrogenase C) Succinate dehydrogenase D) Malate dehydrogenase **Answer: Isocitrate dehydrogenase** 66. **Which part of the cell is the site of the citric acid cycle?** A) Cytoplasm B) Nucleus C) Mitochondria D) Endoplasmic reticulum **Answer: Mitochondria** 67. **Where does the citric acid cycle (Krebs cycle) take place?** A) Cytoplasm B) Mitochondria C) Endoplasmic reticulum D) Nucleus  **Answer: Mitochondria** 68. **What is the product of the citric acid cycle?** A) NADH B) ATP C) CO₂ D) All of the above **Answer: All of the above** 69. **Which molecule is required for the transport of fatty acids into mitochondria for β-oxidation?** A) ATP B) Carnitine C) Coenzyme A D) Acetyl-CoA **Answer: Carnitine** 70. **Which of the following is a type of metabolic pathway that breaks down molecules to release energy?** A) Anabolism B) Catabolism C) Glycogenesis D) Lipogenesis **Answer: Catabolism** 71. **Which metabolic pathway generates the most NADH and FADH₂ per glucose molecule?** A) Glycolysis B) Citric acid cycle C) Electron transport chain D) Fermentation **Answer: Citric acid cycle** 72. **Which molecule is produced by the liver during fatty acid oxidation and used by the brain during fasting?** A) Glucose B) Ketone bodies C) Acetyl-CoA D) ATP **Answer: Ketone bodies** 73. **Which of the following enzymes is involved in the breakdown of triglycerides?** A) Lipase B) Amylase C) Lactase D) Protease **Answer: Lipase** 74. **Where is glycogen stored in the body?** A) Muscle and liver B) Heart and lungs C) Pancreas D) Kidneys **Answer: Muscle and liver** 75. **What is the primary energy source for cells during prolonged fasting?** A) Glucose B) Fatty acids C) Amino acids D) Glycogen **Answer: Fatty acids** 76. **Which process occurs in the cytoplasm and produces pyruvate from glucose?** A) Glycolysis B) Citric acid cycle C) Oxidative phosphorylation D) Beta-oxidation **Answer: Glycolysis** 77. **Which hormone stimulates the breakdown of glycogen?** A) Insulin B) Glucagon C) Epinephrine D) Cortisol **Answer: Glucagon** 78. **What is the main purpose of gluconeogenesis?** A) To break down glucose into pyruvate B) To produce glucose from non-carbohydrate precursors C) To store glucose as glycogen D) To generate ATP **Answer: To produce glucose from non-carbohydrate precursors** 79. **Which of the following is true about the oxidation of fatty acids?** A) It requires the conversion of trans double bonds to cis B) It involves additional enzymes like epimerase and isomerase C) It produces fewer ATP molecules compared to saturated fatty acids D) Both B and C **Answer: Both B and C** 80. **What happens to fatty acids during prolonged fasting or starvation?** A) They are converted into glucose for energy B) They are stored as triglycerides C) They are used for ketone body production to fuel the brain D) They are broken down into amino acids **Answer: They are used for ketone body production to fuel the brain** 81. **What molecule is produced from the final round of β-oxidation of palmitic acid (C16)?** A) Malate B) Acetyl-CoA C) Propionyl-CoA D) Glucose **Answer: Acetyl-CoA** 82. **What is the net ATP yield from the complete β-oxidation of one molecule of palmitic acid (C16)?** A) 108 ATP B) 120 ATP C) 96 ATP D) 80 ATP **Answer: 108 ATP** 83. **Which intermediate is produced when odd-chain fatty acids undergo β-oxidation?** A) Propionyl-CoA B) Acetyl-CoA C) Fumarate D) Succinyl-CoA **Answer: Propionyl-CoA** 84. **What is the first step in fatty acid metabolism?** A) β-oxidation B) Activation of fatty acids C) Synthesis of acetyl-CoA D) Hydrolysis of triglycerides **Answer: Activation of fatty acids** 85. **Which enzyme catalyzes the activation of fatty acids to fatty acyl-CoA?** A) Acetyl-CoA synthetase B) Carnitine acyltransferase C) Acyl-CoA synthetase D) Phospholipase A **Answer: Acyl-CoA synthetase** 86. **Which of the following is true about the oxidation of unsaturated fatty acids?** A) It requires the conversion of trans double bonds to cis B) It produces fewer ATP molecules compared to saturated fatty acids C) It involves additional enzymes like epimerase and isomerase D) All of the above **Answer: All of the above** 87. **What molecule is produced from the final round of β-oxidation of fatty acids?** A) Acetyl-CoA  B) Propionyl-CoA C) Malonyl-CoA D) Glucose **Answer: Acetyl-CoA** 88. **What is the net ATP production from the complete breakdown of one molecule of stearic acid (C18) through β-oxidation?** A) 120 ATP B) 100 ATP C) 108 ATP D) 96 ATP **Answer: 120 ATP** 89. **What happens to the propionyl-CoA produced from the β-oxidation of odd-numbered fatty acids?** A) It is converted into acetyl-CoA B) It enters the citric acid cycle after conversion to succinyl-CoA C) It is used to form glucose D) It is converted into malonyl-CoA for fatty acid synthesis **Answer: It enters the citric acid cycle after conversion to succinyl-CoA** 90. **What is the primary function of ketone bodies?** A) Provide energy for the brain during periods of fasting or low glucose availability B) Aid in the synthesis of fatty acids C) Increase blood glucose levels D) Enhance the storage of triglycerides **Answer: Provide energy for the brain during periods of fasting or low glucose availability** 91. **Which of the following is a ketone body produced during fatty acid metabolism?** A) Acetone B) Acetyl-CoA C) Glucose D) Glycerol **Answer: Acetone** 92. **What is the role of epimerase in the β-oxidation of unsaturated fatty acids?** A) Converts a cis double bond to a trans double bond B) Cleaves the fatty acid chain C) Adds water to the fatty acid chain D) Transfers an acyl group to carnitine **Answer: Converts a cis double bond to a trans double bond** 93. **What is the final product of β-oxidation after multiple rounds of oxidation of a fatty acid?**  A) Propionyl-CoA B) Acetyl-CoA C) NADH D) FADH₂ **Answer: Acetyl-CoA** 94. **Which lipoprotein is often referred to as "bad cholesterol"?** A) HDL B) LDL C) VLDL D) Chylomicrons **Answer: LDL** 95. **What is the role of carnitine in fatty acid metabolism?** A) It catalyzes the breakdown of fatty acids B) It facilitates the transport of fatty acyl-CoA into the mitochondria C) It activates fatty acids for β-oxidation D) It inhibits fatty acid oxidation **Answer: It facilitates the transport of fatty acyl-CoA into the mitochondria** 96. **What molecule is produced during the first step of β-oxidation of fatty acids?** A) Acetyl-CoA B) NADH C) FADH₂ D) Malonyl-CoA **Answer: NADH** 97. **Which enzyme catalyzes the final cleavage of the fatty acyl-CoA in β-oxidation?** A) Acyl-CoA synthetase B) Thiolase C) Dehydrogenase D) Carnitine acyltransferase **Answer: Thiolase** 98. **How many NADH molecules are produced per round of β-oxidation?** A) 2 NADH B) 1 NADH C) 3 NADH D) 0 NADH **Answer: 1 NADH** 99. **Which intermediate is produced from the breakdown of an odd-chain fatty acid?** A) Acetyl-CoA B) Succinyl-CoA C) Propionyl-CoA D) Fumarate **Answer: Propionyl-CoA** 100. **Which enzyme is involved in the formation of ketone bodies?** A) Acetyl-CoA carboxylase B) HMG-CoA synthase C) Carnitine acyltransferase D) Phosphofructokinase **Answer: HMG-CoA synthase** -