Mock Exam Biochemistry Module Revision PDF

**[Mock exam: Biochemistry module -- Revision: 08/01/2025.]** **Carbohydrates** 1. What is the primary storage form of carbohydrates in animals? - A\) Starch - B\) Cellulose - C\) Glycogen - D\) Sucrose 2. Which monosaccharide is a component of RNA? - A\) Fruc...

**[Mock exam: Biochemistry module -- Revision: 08/01/2025.]** **Carbohydrates** 1. What is the primary storage form of carbohydrates in animals? - A\) Starch - B\) Cellulose - C\) Glycogen - D\) Sucrose 2. Which monosaccharide is a component of RNA? - A\) Fructose - B\) Deoxyribose - C\) Ribose - D\) Glucose 3. Which of these is a disaccharide? - A\) Glucose - B\) Fructose - C\) Lactose - D\) Galactose 4. Which polysaccharide consists of straight chains of glucose linked by α-1,4-glycosidic bonds? - A\) Amylopectin - B\) Cellulose - C\) Amylose - D\) Chitin 5. What is gluconeogenesis? - A\) Breakdown of glycogen - B\) Formation of glucose from non-carbohydrate sources - C\) Conversion of glucose to pyruvate - D\) Synthesis of glycogen 6. **Sucrose is formed from monomers X and Y as shown in Figure below. Which of the following is Monomer X:** A\) Glucose B\) Fructose C\) Maltose D\) Sucrase **Proteins** 7. Which type of bond stabilizes the primary structure of proteins? - A\) Disulfide bond - B\) Ionic bond - C\) Peptide bond - D\) Hydrogen bond 8. What determines the tertiary structure of a protein? - A\) The sequence of nucleotides - B\) The type of glycosidic bonds - C\) Interactions between R-groups - D\) Hydrogen bonds only 9. Haemoglobin is an example of which level of protein structure?§ - A\) Primary - B\) Secondary - C\) Tertiary - D\) Quaternary 10. Which amino acid contains a sulfhydryl group in its side chain? - A\) Lysine - B\) Serine - C\) Cysteine - D\) Alanine 11. Enzymes are primarily composed of: - A\) Carbohydrates - B\) Lipids - C\) Proteins - D\) Nucleotides 12. **Which of the following could not be an amino acid?**  **Lipids** 13. Which class of lipids is the primary component of biological membranes? - A\) Steroids - B\) Phospholipids - C\) Triglycerides - D\) Waxes 14. What type of reaction is involved in the breakdown of triglycerides? - A\) Condensation - B\) Hydrolysis - C\) Oxidation - D\) Dehydration 15. A fatty acid with one double bond is classified as: - A\) Saturated - B\) Monounsaturated - C\) Polyunsaturated - D\) Trans fat 16. The process by which lipids are transported in the blood involves: - A\) Chylomicrons - B\) Hemoglobin - C\) Albumin - D\) Lipase 17. Which enzyme is responsible for breaking down triglycerides into fatty acids and glycerol? - A\) Amylase - B\) Lipase - C\) Peptidase - D\) Phosphatase **Nucleic Acids** 18. Which nitrogenous base is found in RNA but not in DNA? - A\) Adenine - B\) Cytosine - C\) Thymine - D\) Uracil 19. What type of sugar is present in DNA? - A\) Ribose - B\) Deoxyribose - C\) Fructose - D\) Sucrose 20. The process of converting DNA to mRNA is called: - A\) Translation - B\) Replication - C\) Transcription - D\) Splicing 21. A nucleotide consists of: - A\) A sugar and a phosphate group only - B\) A sugar, phosphate group, and nitrogenous base - C\) A sugar and nitrogenous base only - D\) Two nitrogenous bases **Metabolism** 22. During glycolysis, glucose is converted into: - A\) Pyruvate - B\) Lactate - C\) Citric acid - D\) Acetyl-CoA 23. Which metabolic pathway produces the most ATP? - A\) Glycolysis - B\) Electron transport chain - C\) Citric acid cycle - D\) Fermentation 24. The urea cycle occurs in which organ? - A\) Kidney - B\) Liver - C\) Pancreas - D\) Muscle 25. The breakdown of fatty acids to generate acetyl-CoA is called: - A\) Lipogenesis - B\) Beta-oxidation - C\) Glycogenolysis - D\) Ketogenesis 26. What is the role of carnitine in metabolism? - A\) Activates lipases - B\) Transports fatty acids into mitochondria - C\) Synthesizes cholesterol - D\) Forms triglycerides **Enzymes and Energy** 27. Enzymes increase reaction rates by: - A\) Providing energy - B\) Increasing temperature - C\) Lowering activation energy - D\) Changing substrate concentration 28. ATP is primarily produced in the: - A\) Cytosol - B\) Golgi apparatus - C\) Mitochondria - D\) Nucleus 29. Which step in cellular respiration generates water? - A\) Glycolysis - B\) Citric acid cycle - C\) Electron transport chain - D\) Fermentation 30. Inhibitors that bind to the active site of an enzyme are classified as: - A\) Allosteric inhibitors - B\) Competitive inhibitors - C\) Non-competitive inhibitors - D\) Cofactors 31. **The diagram below represents a simplified version of the electron transport chain and chemiosmosis. Which row correctly describes the events labelled 1-4 above?** A diagram of a diagram of a circle Description automatically generated with medium confidence **1** **2** **3** **4** -------- ---------------------------------------------------------------- -------------------------------------------------------------- ----------------------------------------- ----------------------- **A)** Protons move across the cristae into the intermembrane space Protons move across the cristae into the intermembrane space Protons are pumped through ATP synthase ADP is phosphorylated **B)** Protons move across the cristae into the matrix Protons move across the cristae into the matrix Protons are pumped through ATP synthase ATP is phosphorylated **C)** Protons move across the cristae into the intermembrane space Protons move across the cristae into the intermembrane space Protons diffuse through ATP synthase ADP is phosphorylated **D)** Electrons move across the cristae into the intermembrane space Protons move across the cristae into the intermembrane space Protons diffuse through ATP synthase ATP is synthesized **Carbohydrate Metabolism** 32. What is the primary substrate for glycolysis? - A\) Fructose - B\) Glucose - C\) Galactose - D\) Sucrose 33. In glycolysis, which enzyme converts fructose-6-phosphate into fructose-1,6-bisphosphate? - A\) Hexokinase - B\) Aldolase - C\) Phosphofructokinase - D\) Glucokinase 34. The main regulatory step of the glycolysis pathway is catalyzed by: - A\) Hexokinase - B\) Pyruvate kinase - C\) Phosphofructokinase-1 - D\) Enolase 35. What is the fate of pyruvate in anaerobic conditions in human cells? - A\) Ethanol - B\) Lactate - C\) Acetyl-CoA - D\) Oxaloacetate 36. The primary purpose of the citric acid cycle is to: - A\) Generate ATP directly - B\) Produce NADH and FADH2 for oxidative phosphorylation - C\) Store glucose as glycogen - D\) Convert carbohydrates into fatty acids 37. Which enzyme in gluconeogenesis bypasses the phosphofructokinase step of glycolysis? - A\) Glucose-6-phosphatase - B\) Fructose-1,6-bisphosphatase - C\) Pyruvate carboxylase - D\) Phosphoenolpyruvate carboxykinase 38. During fasting, gluconeogenesis is stimulated by which hormone? - A\) Glucagon - B\) Insulin - C\) Adrenaline - D\) Thyroxine **Lipid Metabolism** 39. Which molecule is essential for transporting long-chain fatty acids into mitochondria? - A\) Carnitine - B\) Coenzyme Q - C\) ATP - D\) Citrate 40. The breakdown of triglycerides in adipose tissue is catalyzed by: - A\) Lipoprotein lipase - B\) Hormone-sensitive lipase - C\) Acetyl-CoA carboxylase - D\) Fatty acyl-CoA synthetase 41. The primary product of beta-oxidation of fatty acids is: - A\) Pyruvate - B\) Acetyl-CoA - C\) Malonyl-CoA - D\) Glycerol 42. The primary site of ketogenesis is: - A\) Liver - B\) Brain - C\) Muscle - D\) Adipose tissue 43. Excessive beta-oxidation of fatty acids can lead to: - A\) Increased cholesterol synthesis - B\) Ketone body accumulation - C\) Fatty liver disease - D\) Hypoglycemia 44. Cholesterol is synthesized from: - A\) Acetyl-CoA - B\) Malonyl-CoA - C\) NADH - D\) Palmitate 45. In the synthesis of fatty acids, acetyl-CoA is first converted to: - A\) Malonyl-CoA - B\) Citrate - C\) Oxaloacetate - D\) Pyruvate 46. Which enzyme is inhibited by malonyl-CoA during fatty acid metabolism? - A\) Hormone-sensitive lipase - B\) Carnitine acyltransferase I - C\) Fatty acyl-CoA synthetase - D\) Acetyl-CoA carboxylase **Protein Metabolism** 47. Which amino acid is a key nitrogen donor in amino acid transamination? - A\) Glutamate - B\) Aspartate - C\) Alanine - D\) Serine 48. Which enzyme catalyzes the removal of an amino group from glutamate? - A\) Glutamate dehydrogenase - B\) Transaminase - C\) Aminotransferase - D\) Carbamoyl phosphate synthetase 49. The urea cycle takes place primarily in: - A\) Cytoplasm and mitochondria of liver cells - B\) Mitochondria of kidney cells - C\) Cytoplasm of muscle cells - D\) Peroxisomes of adipose cells 50. The toxic ammonia generated during amino acid metabolism is converted into: - A\) Uric acid - B\) Urea - C\) Glutamine - D\) Alanine 51. During starvation, amino acids are primarily used to generate: - A\) Fatty acids - B\) Glucose - C\) Ketone bodies - D\) ATP 52. What is the role of glutamine in nitrogen metabolism? - A\) Directly converts ammonia to urea - B\) Acts as a nitrogen carrier between tissues - C\) Degrades purines - D\) Activates transamination reactions **Nucleic Acid Metabolism** 53. The de novo synthesis of purines begins with: - A\) Ribose-5-phosphate - B\) Glycine - C\) Aspartate - D\) Citrulline 54. Which enzyme catalyzes the conversion of dUMP to dTMP in nucleotide metabolism? - A\) Ribonucleotide reductase - B\) Thymidylate synthase - C\) Adenylate kinase - D\) DNA polymerase 55. What is the role of the salvage pathway in nucleotide metabolism? - A\) Breakdown of nucleotides to uric acid - B\) Recycling of purine and pyrimidine bases - C\) De novo synthesis of nucleotides - D\) Oxidative degradation of DNA 56. **Which enzyme is responsible for the synthesis of PRPP (phosphoribosyl pyrophosphate)?** A\) PRPP synthase B\) Thymidine kinase C\) Ribose phosphate isomerase D\) Carbamoyl phosphate synthetase 57. **Which enzyme catalyses the first step of the urea cycle?** A\) Arginase B\) Carbamoyl phosphate synthetase I C\) Ornithine transcarbamylase D\) Arginosuccinate synthase 58. **In the DNA double helix, bases are held together by:** A\) Covalent bonds B\) Hydrogen bonds C\) Ionic bonds D\) Disulfide bonds 59. **Which enzyme is responsible for unwinding the DNA double helix?** A\) DNA polymerase B\) RNA polymerase C\) Helicase D\) Ligase 60. **In DNA, adenine pairs with:** A\) Cytosine B\) Guanine C\) Thymine D\) Uracil **Answer sheet for Multiple choice questions:** **Question** **Choice** **Question** **Choice** -------------- ------------ -------------- ------------ **1** **31** **2** **32** **3** **33** **4** **34** **5** **35** **6** **36** **7** **37** **8** **38** **9** **39** **10** **40** **11** **41** **12** **42** **13** **43** **14** **44** **15** **45** **16** **46** **17** **47** **18** **48** **19** **49** **20** **50** **21** **51** **22** **52** **23** **53** **24** **54** **25** **55** **26** **56** **27** **57** **28** **58** **29** **59** **30** **60**