Vitamins and Hormones MCQs

By: Prof. Dr. Fazal Rehman | Last updated: May 22, 2025

1. : Which is correct regarding Cholecalciferol (Vit.D3)?
(A) It is a sterol
(B) It is converted to a biologically active form by UV light
(C) It is a hormone precursor
(D) Both A, B and C

2. : All hormone receptor-enzymes:
(A) Alter gene expression
(B) Consist of more than one subunit
(C) Act by phosphorylating tyrosines
(D) Both A, B and C

3. : Which is correct regarding Steroid hormones?
(A) Bind cell surface receptors
(B) Mediate their effects through second messengers
(C) Have a very rapid effect (within seconds) on target cells
(D) Are insoluble in blood

4. : Which enzyme requires biotin as a coenzyme?
(A) Pyruvate kinase
(B) Acetyl CoA carboxylase
(C) Phosphoenolpyruvate carboxykinase
(D) Both A, B and C

5. : Group I hormones act through which of the following?
(A) Receptor enzymes
(B) G-protein coupled receptors
(C) Nuclear receptors
(D) Gated ion channels

6. : Group II hormones do not act through which of the following?
(A) Receptor enzymes
(B) Nuclear receptors
(C) G-protein coupled receptors
(D) Gated ion channels

7. : Which chemical is not a hormone?
(A) Cyclic AMP (cAMP)
(B) Nitric oxide
(C) Retinoic acid
(D) Vitamin D

8. : What happens in a cell as a result of insulin binding to its receptor?
(A) Cyclic GMP is produced
(B) Glucose is released from the cell
(C) GLUT4 moves from the plasma membrane to internal membrane vesicles
(D) Glycogen synthase becomes activated

9. : Which is correct regarding the hormone epinephrine?
(A) Its intracellular signal persists long after it has stopped binding its receptor
(B) It promotes the mobilization of glucose from glycogen
(C) It must be present in high concentrations to carry out its effects
(D) Both A, B and C

10. : Which is correct regarding Vitamin C?
(A) Helps in conversion of Beta carotenes to Vitamin A
(B) It helps in production of prothrombin
(C) It is essential for formation of collagen
(D) It helps in phosphorylation process

11. : Of the two types of diabetes, which situation is unique to type II diabetes?
(A) An inability to take up glucose efficiently from the blood
(B) An inability to respond to insulin
(C) An inability to produce sufficient insulin
(D) High levels of glucose in urine

12. : Insulin causes all of the following excluding which of the following?
(A) Increased glucose uptake and utilization
(B) Increased amino acid uptake
(C) Increased fat utilization
(D) Shift of K⁺ from ECF to cells

13. : Synthesis of Na⁺/K⁺ ATPase pump is stimulated by:
(A) ACTH
(B) Thyroid Hormones
(C) Epinephrine
(D) PTH

14. : The release of insulin from the pancreas is triggered or stimulated by:
(A) Low intracellular levels of glucose
(B) A drop in intracellular ATP
(C) The opening of Ca²⁺ channels in the plasma membrane
(D) Stimuli from the sympathetic nervous system

15. : Insulin deficiency:
(A) Depresses protein synthesis
(B) Increases protein degradation
(C) Depresses lipogenesis
(D) Increases nitrogen excretion

16. : Insulin acts by all of the following, excluding which of the following?
(A) Stimulates glycogenesis
(B) Decreases renal reabsorption of glucose
(C) Inhibits gluconeogenesis
(D) Increases utilization of glucose

17. : Thiouracil inhibits thyroid function by which of the following?
(A) Inhibition of pituitary
(B) Degradation of thyrotropin
(C) Formation of thiocyanate
(D) Inhibition of thyroxine synthesis

18. : Which of the following is the main and key mechanism of excretion of steroid hormones?
(A) Phenolic sulphate esters
(B) Estradiol
(C) Glucuronides
(D) Unchanged

19. : Which is the quickest acting hormone?
(A) Thyroid hormones
(B) Epinephrine
(C) Testosterone
(D) Vitamin D

20. : What are ‘Orphan Receptors’?
(A) The membrane receptors with unknown second messenger
(B) The membrane receptors with unknown ligand
(C) Nuclear hormone responsive element with unknown ligand
(D) Nuclear hormone responsive elements with unknown gene

21. : Which is correct regarding leptin?
(A) It is synthesized in the hypothalamus
(B) It makes ATP synthesis more efficient
(C) It allows continuous oxidation of fatty acids
(D) Its levels in the blood are controlled by signals in the brain

22. : Which vitamin is responsible for vision?
(A) Vitamin D
(B) Retinol
(C) Tocopherols
(D) Vitamin K

23. : Which vitamin derivative is the co-enzyme for aminotransferases?
(A) Pyridoxal phosphate
(B) Methyl Cobalamin
(C) NADH
(D) Tetrahydrofolate

24. : Endogenous Vitamin D synthesis happens in?
(A) Skin
(B) Liver
(C) Epididymis
(D) Adrenal gland

25. : Vitamin C is a cofactor in the enzymatic transformation of which of the following?
(A) Hydroxylysine to al-lysine (Aldehyde derivative)
(B) Glutamate to keto-glutarate
(C) Proline to hydroxyproline
(D) Lysine to desmosine

26. : Which vitamin is important for carboxylation reactions?
(A) Biotin
(B) Pyridoxine
(C) Ascorbic acid
(D) Tocopherol

27. : Vitamin which prevents auto-oxidation of fats and other molecules:
(A) Biotin
(B) Tocopherol
(C) Pyridoxine
(D) Vitamin A

28. : Vitamin essential for transamination reactions is:
(A) B6
(B) B2
(C) B1
(D) B12

29. : Vitamin B1 participates in which of the following?
(A) Single ‘N’ transfer
(B) Carboxylation
(C) Two-carbon transfer
(D) One-carbon transfer

30. : Sulfa drugs such as sulfanilamide are effective antibacterial agents because they act as:
(A) Competitive inhibitors for PABA synthesis
(B) Noncompetitive inhibitors for PABA synthesis
(C) Competitive inhibitors of THF synthesis
(D) Competitive inhibitors for folate synthesis

31. : Water-soluble vitamin necessary for the synthesis of coenzyme:
(A) Pantothenic acid
(B) Vitamin C
(C) Thiamine
(D) Biotin

32. : Which one of the following vitamins is a precursor of the coenzyme involved in glycogenolysis decarboxylation reactions?
(A) Thiamine
(B) Pantothenic acid
(C) Pyridoxine
(D) Folate

33. : Vitamin B12 is a:
(A) Porphyrin-like compound
(B) Copper-containing vitamin
(C) Fat-soluble vitamin
(D) Growth factor essential for E. coli

34. : Which of the following is the most active form of Vitamin D?
(A) 1α-calciferol
(B) 24,25-dihydroxycalciferol
(C) 25-hydroxycholecalciferol
(D) 1,25-dihydroxycholecalciferol

35. : Methylmalonicaciduria is seen in deficiency of which of the following?
(A) Pyridoxine
(B) Riboflavin
(C) Cobalamin
(D) Folic Acid

36. : Glucagon-initiated phosphorylation:
(A) Activates glycogen phosphorylase
(B) Activates lipoprotein lipase
(C) Deactivates adipose tissue lipase
(D) Both A, B, and C

37. : Which vitamins act like a hormone?
(A) Vitamin D
(B) Vitamin A
(C) Vitamin E
(D) Both A and B

38. : Which is not seen in scurvy?
(A) Impaired cement formation
(B) Impaired trabeculation
(C) Osteoporosis
(D) Impaired cartilage

39. : Vitamin B12 participates in the metabolism of:
(A) Odd-chain fatty acids
(B) Malonyl CoA to Succinyl CoA
(C) Homocysteine to Methionine
(D) Both A, B, and C

40. : Patients with severe renal disease may not be able to use dietary sources for:
(A) Vitamin A
(B) Vitamin B
(C) Vitamin D
(D) Vitamin C

41. : Growth of bacteria requiring p-aminobenzoic acid is inhibited by:
(A) Sulphonamides
(B) Citrovorum factor
(C) Tetrahydrofolic acid
(D) Penicillin

42. : Vitamin A hypervitaminosis causes injury to:
(A) Mitochondria
(B) Lysosomes
(C) Microtubules
(D) Endoplasmic reticulum

43. : Which is formed without participation of any vitamin?
(A) Gamma-carboxy-Glutamate
(B) Hydroxyproline
(C) Hydroxylysine
(D) Phosphoserine

44. : Biological activity of tocopherols has been attributed, in part, to their action as:
(A) Anticoagulants
(B) Antioxidants
(C) Antidotes for selenium poisoning
(D) Both A, B, and C

45. : Serpentine receptors (G-Protein coupled receptors):
(A) Generate second messengers
(B) Are ion channels
(C) Act in the nucleus
(D) Have a single transmembrane domain

46. : Which is correct regarding steroid hormones?
(A) They are all derived from testosterone
(B) They travel through the bloodstream on protein carriers
(C) They are all synthesized in the adrenal gland
(D) They carry messages between tissues

47. : Dermatitis, diarrhea, and dementia are seen in deficiency of:
(A) Thiamine
(B) Riboflavin
(C) Folate
(D) Niacin

48. : Cholesterol is a precursor molecule for all of the following, excluding which of the following?
(A) Testosterone
(B) Vitamin D
(C) Vitamin K
(D) Bile salts

49. : Which is a cofactor for fatty acid biosynthesis?
(A) Thiamine
(B) Pyridoxal Phosphate
(C) Cobalamine
(D) Biotin

50. : Which vitamin is needed for the optimum activity of tryptophan pyrrolase?
(A) Thiamine
(B) Vitamin B12
(C) Folic acid
(D) Vitamin C

51. : Which vitamin is needed in the conversion of pyruvate to oxaloacetate?
(A) B1
(B) Pyridoxine
(C) Vitamin C
(D) Biotin

52. : Which vitamin is considered very important to withstand stressful conditions?
(A) Vitamin A
(B) Vitamin C
(C) Vitamin B12
(D) Vitamin D

53. : Every hormone __________.
(A) Is able to enter their target cells
(B) Is water-soluble
(C) Acts through binding receptors
(D) Acts by changing the expression of specific genes

54. : The high ‘Sensitivity’ of signal transduction is due to which of the following?
(A) High concentration of the hormone
(B) Amplification of the signal through a multistep activation
(C) Specificity of hormone-receptor interaction
(D) Both A, B and C

55. : Which vitamin is needed when carbohydrate intake is increased?
(A) B12
(B) B6
(C) B1
(D) Pantothenic acid

56. : Which water-soluble vitamin is not important for the normal activity of the Krebs cycle?
(A) Riboflavin
(B) Pantothenic acid
(C) Biotin
(D) Thiamine

57. : Which is correct regarding endocrine function?
(A) The endocrine molecule acts on the cell of its synthesis
(B) The endocrine molecule acts on the cell adjacent to that of its synthesis
(C) All endocrine molecules require a receptor to act
(D) All endocrine molecules stimulate synthesis of specific proteins

58. : Chemically, the hormones are _______.
(A) Polypeptides
(B) Neurotransmitters
(C) Steroids
(D) Both A, B and C

59. : Biotin:
(A) Serves as a cofactor in dehydrogenase reactions
(B) Transfers one-carbon groups
(C) Is a co-factor that transfers acetyl groups
(D) Both A, B and C

60. : Methotrexate is helpful and used as an anticancer drug because it ________.
(A) Competitively inhibits the conversion of dihydrofolate to tetrahydrofolate
(B) Irreversibly inhibits the conversion of dihydrofolate to tetrahydrofolate
(C) Directly inhibits DNA synthesis
(D) Competitively inhibits the synthesis of folate

61. : Thiamine deficiency can be diagnosed by which of the following?
(A) Blood Pyruvate estimation
(B) Urinary thiamine levels
(C) RBC Transketolase estimation
(D) Both A, B and C

62. : The highest concentration of Ascorbic acid is found in:
(A) Adrenal gland
(B) Kidneys
(C) Testes
(D) Eye

63. : Normal urinary excretion of ascorbic acid is:
(A) 5-10 mg/24 h
(B) 10-15 mg/24 h
(C) 50-100 mg/24 h
(D) 15-50 mg/24 h

64. : Which vitamin is usually excreted both through feces as well as urine?
(A) Pyridoxine
(B) Folic acid
(C) Pantothenic acid
(D) Vitamin B12

65. : In scurvy, the main biochemical defect lies in:
(A) Formation of hydroxyproline
(B) Attachment of sugars to Asn
(C) Non-covalent linkage between strands
(D) Cross-linking of Tropocollagen

66. : A vitamin related to a co-factor in glycine metabolism is:
(A) Folic acid
(B) Vitamin E
(C) Thiamine
(D) Cobalamin

67. : Vitamin K plays an important role in ______.
(A) Posttranslational modification of proteins
(B) Synthesis of Osteocalcin
(C) Synthesis of prothrombin proconvertin
(D) Both A, B and C

68. : Part of the Nicotinic acid requirement of the body may be fulfilled from:
(A) Pyridoxine
(B) Tyrosine
(C) Tryptophan
(D) Methionine

69. : Which is not a feature of niacin deficiency?
(A) Conjunctival congestion
(B) Red tongue
(C) Psychosis
(D) Diarrhea