1. : Which of the following is the main storage form of carbohydrates in animals?
(A) Starch
(B) Glycogen
(C) Cellulose
(D) Glucose
2. : Enzymes that speed up biochemical reactions are mainly composed of:
(A) Lipids
(B) Proteins
(C) Vitamins
(D) Minerals
3. : Which vitamin acts as a coenzyme in carbohydrate metabolism?
(A) Vitamin B₁ (Thiamine)
(B) Vitamin A
(C) Vitamin D
(D) Vitamin K
4. : The end product of glycolysis is:
(A) Glucose
(B) Pyruvate
(C) Lactate
(D) Acetyl-CoA
5. : Which biomolecule provides the highest energy per gram?
(A) Carbohydrates
(B) Proteins
(C) Fats
(D) Vitamins
6. : The urea cycle primarily occurs in which organ?
(A) Kidney
(B) Liver
(C) Pancreas
(D) Intestine
7. : Which vitamin is a cofactor for collagen synthesis?
(A) Vitamin D
(B) Vitamin C
(C) Vitamin E
(D) Vitamin K
8. : The process of converting glucose to glycogen is called:
(A) Glycolysis
(B) Glycogenesis
(C) Gluconeogenesis
(D) Glycogenolysis
9. : The biochemical breakdown of fats produces:
(A) Glycerol and fatty acids
(B) Amino acids
(C) Monosaccharides
(D) Alcohols
10. : Which enzyme catalyzes the conversion of starch to maltose?
(A) Lipase
(B) Amylase
(C) Pepsin
(D) Trypsin
11. : The TCA cycle occurs in the:
(A) Cytoplasm
(B) Nucleus
(C) Mitochondria
(D) Endoplasmic reticulum
12. : Which of the following is a ketogenic amino acid?
(A) Lysine
(B) Alanine
(C) Glycine
(D) Serine
13. : NAD⁺ functions as a:
(A) Substrate
(B) Coenzyme in redox reactions
(C) Structural protein
(D) Hormone
14. : The process of glucose synthesis from non-carbohydrate sources is known as:
(A) Glycolysis
(B) Gluconeogenesis
(C) Fermentation
(D) Glycogenolysis
15. : The enzyme lipase helps in the digestion of:
(A) Proteins
(B) Fats
(C) Carbohydrates
(D) Vitamins
16. : The oxidation of one molecule of glucose yields approximately:
(A) 2 ATP
(B) 18 ATP
(C) 36–38 ATP
(D) 10 ATP
17. : Which of the following is a water-soluble vitamin?
(A) Vitamin D
(B) Vitamin K
(C) Vitamin C
(D) Vitamin E
18. : What is the main nitrogenous waste product in humans?
(A) Ammonia
(B) Uric acid
(C) Urea
(D) Creatinine
19. : The enzyme responsible for breaking down proteins into peptides is:
(A) Pepsin
(B) Amylase
(C) Lipase
(D) Maltase
20. : Beta-oxidation of fatty acids occurs in the:
(A) Cytosol
(B) Mitochondria
(C) Nucleus
(D) Ribosome
21. : The main function of insulin is to:
(A) Decrease blood glucose
(B) Increase blood glucose
(C) Digest fats
(D) Store protein
22. : Which vitamin acts as a coenzyme in amino acid metabolism?
(A) Vitamin B₆ (Pyridoxine)
(B) Vitamin B₁₂
(C) Vitamin C
(D) Vitamin E
23. : The Cori cycle connects which two organs?
(A) Liver and muscle
(B) Kidney and heart
(C) Brain and pancreas
(D) Stomach and intestine
24. : The deficiency of Vitamin B₁₂ causes:
(A) Rickets
(B) Pernicious anemia
(C) Night blindness
(D) Scurvy
25. : Which metabolic pathway produces lactic acid during oxygen deficiency?
(A) Anaerobic glycolysis
(B) Krebs cycle
(C) Beta-oxidation
(D) Electron transport chain
26. : The enzyme hexokinase catalyzes the:
(A) First step of glycolysis
(B) Last step of glycolysis
(C) ATP synthesis
(D) Protein breakdown
27. : The main function of coenzyme Q (ubiquinone) is in:
(A) DNA replication
(B) Electron transport chain
(C) Protein folding
(D) Vitamin synthesis
28. : The main lipid found in cell membranes is:
(A) Cholesterol
(B) Phospholipid
(C) Triglyceride
(D) Steroid
29. : The conversion of pyruvate to lactate is catalyzed by:
(A) Lactate dehydrogenase
(B) Pyruvate kinase
(C) Hexokinase
(D) Amylase
30. : Which mineral acts as a cofactor for many enzymes?
(A) Iron
(B) Magnesium
(C) Sodium
(D) Calcium
31. : Which vitamin is essential for oxidative phosphorylation?
(A) Vitamin B₂ (Riboflavin)
(B) Vitamin K
(C) Vitamin A
(D) Vitamin D
32. : The hormone glucagon mainly acts on the:
(A) Brain
(B) Liver
(C) Stomach
(D) Kidneys
33. : Cholesterol is a precursor of:
(A) Fatty acids
(B) Bile acids and steroid hormones
(C) Proteins
(D) Glucose
34. : The enzyme responsible for DNA synthesis is:
(A) RNA polymerase
(B) DNA polymerase
(C) Ligase
(D) Helicase
35. : The RQ (Respiratory Quotient) for carbohydrate metabolism is:
(A) 0.7
(B) 1.0
(C) 0.8
(D) 0.9
36. : Which vitamin prevents oxidative damage to cells?
(A) Vitamin E
(B) Vitamin K
(C) Vitamin D
(D) Vitamin B₁
37. : The main site of protein synthesis is:
(A) Mitochondria
(B) Ribosome
(C) Nucleus
(D) Cytoskeleton
38. : Which amino acid is the precursor of serotonin?
(A) Tryptophan
(B) Tyrosine
(C) Methionine
(D) Phenylalanine
39. : Which of the following is a reducing sugar?
(A) Sucrose
(B) Glucose
(C) Cellulose
(D) Starch
40. : Fatty acids are transported in the blood as:
(A) Free fatty acids bound to albumin
(B) Simple lipids
(C) Water-soluble proteins
(D) Glycerol only
41. : The enzyme responsible for fat digestion in the small intestine is:
(A) Lipase
(B) Pepsin
(C) Trypsin
(D) Amylase
42. : Which vitamin deficiency causes megaloblastic anemia?
(A) Vitamin C
(B) Folic acid
(C) Vitamin K
(D) Vitamin A
43. : The process by which amino groups are removed from amino acids is called:
(A) Deamination
(B) Transamination
(C) Decarboxylation
(D) Oxidation
44. : The enzyme that converts sucrose into glucose and fructose is:
(A) Invertase
(B) Maltase
(C) Amylase
(D) Sucrase
45. : The term “essential amino acids” refers to those which:
(A) Can be synthesized in the body
(B) Cannot be synthesized in the body
(C) Are stored in the liver
(D) Are used in DNA synthesis
46. : Which vitamin is required for blood coagulation?
(A) Vitamin D
(B) Vitamin K
(C) Vitamin E
(D) Vitamin B₂
47. : Gluconeogenesis occurs mainly during:
(A) Starvation and fasting
(B) High carbohydrate intake
(C) Exercise only
(D) Sleep
48. : Which compound is the common intermediate in carbohydrate, fat, and protein metabolism?
(A) Acetyl-CoA
(B) Pyruvate
(C) Glycerol
(D) Lactic acid
49. : The deficiency of niacin results in:
(A) Pellagra
(B) Rickets
(C) Scurvy
(D) Beriberi
50. : The first step in protein digestion occurs in the:
(A) Small intestine
(B) Stomach
(C) Mouth
(D) Large intestine