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Vitamin classification and functions: NEET MCQs with answers

50 questions on this topic of Biomolecules (NEET 2027 syllabus). Here are 12; tap one to see its answer and explanation.

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easy

1. Which of the following dietary sources is rich in Vitamin D as specifically listed in NCERT?

  1. Exposure to sunlight, fish, and egg yolk
  2. Citrus fruits, amla, and green leafy vegetables
  3. Carrots, butter, and papaya
  4. Yeast, milk, and whole cereals
Show answer and explanation

Answer: (A) Exposure to sunlight, fish, and egg yolk

According to NCERT, dietary sources of Vitamin D include exposure to sunlight, fish, and egg yolk. Citrus fruits are rich in Vitamin C, carrots in Vitamin A, and yeast and cereals in B-group vitamins.

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2. Consider the following pairs of vitamins and their primary biochemical or physiological roles: (a) Vitamin K - Essential for the synthesis of prothrombin and blood coagulation factors (b) Vitamin B₁ - Serves as coenzyme thiamine pyrophosphate in carbohydrate metabolism (c) Vitamin D - Regulates calcium and phosphate homeostasis and bone mineralization (d) Vitamin C - Essential for hydroxylation of proline and lysine in collagen biosynthesis How many of the above pairs are correctly matched?

  1. Four
  2. Two
  3. Three
  4. One
Show answer and explanation

Answer: (A) Four

All four pairs are correct. Vitamin K is vital for carboxylation required in prothrombin synthesis. Vitamin B₁ forms TPP for decarboxylation in carbohydrate breakdown. Vitamin D regulates Ca²⁺/PO₄³⁻ absorption for bone health. Vitamin C maintains Fe²⁺ state in prolyl and lysyl hydroxylases for mature collagen formation.

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3. A nutrition scientist analyzed four unknown vitamin preparations (W, X, Y, and Z): 1. Vitamin W contains a fused benzopterin-derived ring system and produces a yellow-orange fluorescent solution. 2. Vitamin X is a steroid derivative containing a cyclopentanoperhydrophenanthrene-derived seco-skeleton. 3. Vitamin Y contains an isoprene-derived hydrocarbon side chain and is insoluble in water. 4. Vitamin Z contains a pyrrole-derived corrin ring coordinating a cobalt ion. Which combination accurately identifies W, X, Y, and Z?

  1. W = Thiamine, X = Vitamin E, Y = Vitamin D, Z = Vitamin B₆
  2. W = Riboflavin, X = Vitamin D, Y = Vitamin A, Z = Vitamin B₁₂
  3. W = Riboflavin, X = Vitamin A, Y = Vitamin D, Z = Vitamin B₁₂
  4. W = Pyridoxine, X = Vitamin D, Y = Vitamin K, Z = Vitamin B₁
Show answer and explanation

Answer: (B) W = Riboflavin, X = Vitamin D, Y = Vitamin A, Z = Vitamin B₁₂

Riboflavin (B₂) contains an isoalloxazine (flavin) ring and gives a characteristic yellow fluorescence. Vitamin D is a secosteroid related to cholesterol. Vitamin A (retinol) is an isoprenoid polyene alcohol insoluble in water. Vitamin B₁₂ (cyanocobalamin) contains a cobalt-coordinated corrin macrocycle.

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4. Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A): Excessive intake of Vitamin A and Vitamin D can lead to toxic accumulation called hypervitaminosis in the human body. Reason (R): Fat-soluble vitamins dissolve in organic lipids and are stored in adipose tissue and liver rather than being readily excreted. In the light of the above statements, choose the most appropriate answer:

  1. Both (A) and (R) are true and (R) is the correct explanation of (A)
  2. Both (A) and (R) are true but (R) is not the correct explanation of (A)
  3. (A) is true but (R) is false
  4. (A) is false but (R) is true
Show answer and explanation

Answer: (A) Both (A) and (R) are true and (R) is the correct explanation of (A)

Vitamins A and D are fat-soluble vitamins. Unlike water-soluble vitamins, they cannot be excreted readily through urine and get stored in the liver and adipose tissues; hence, excessive doses cause accumulation and toxicity (hypervitaminosis).

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5. Deficiency of which of the following vitamins leads to increased blood clotting time?

  1. Vitamin K
  2. Vitamin E
  3. Vitamin B₆
  4. Vitamin B₂
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Answer: (A) Vitamin K

Vitamin K is essential for the synthesis of prothrombin and other clotting factors. Its deficiency results in an increased blood clotting time.

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6. A sample of four organic compounds isolated from natural sources was tested for solubility and functional properties: Compound P: Soluble in water, deficiency causes convulsions. Compound Q: Soluble in fat, deficiency causes prolonged bleeding. Compound R: Soluble in water, stored in liver, deficiency leads to pernicious anaemia. Compound S: Soluble in fat, deficiency causes fragility of RBCs. Identify P, Q, R, and S respectively:

  1. Riboflavin, Phylloquinone, Thiamine, Calciferol
  2. Thiamine, Calciferol, Riboflavin, Tocopherol
  3. Pyridoxine, Tocopherol, Cyanocobalamin, Phylloquinone
  4. Pyridoxine, Phylloquinone, Cyanocobalamin, Tocopherol
Show answer and explanation

Answer: (D) Pyridoxine, Phylloquinone, Cyanocobalamin, Tocopherol

Compound P is Vitamin B₆ (Pyridoxine, water-soluble, causes convulsions). Compound Q is Vitamin K (Phylloquinone, fat-soluble, causes delayed clotting). Compound R is Vitamin B₁₂ (Cyanocobalamin, water-soluble but stored in liver, causes pernicious anaemia). Compound S is Vitamin E (Tocopherol, fat-soluble, causes RBC fragility).

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7. Which of the following organic compounds functions as Vitamin C and belongs chemically to the class of lactones?

  1. Nicotinic acid
  2. Ascorbic acid
  3. Folic acid
  4. Pantothenic acid
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Answer: (B) Ascorbic acid

Vitamin C is chemically known as ascorbic acid. Structurally, it is an enediol lactone of an acid derived from a hexose sugar and exhibits strong reducing properties.

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8. Which of the following B-group vitamins cannot be excreted readily in urine and is instead stored in human liver?

  1. Vitamin B₁
  2. Vitamin B₂
  3. Vitamin B₁₂
  4. Vitamin B₆
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Answer: (C) Vitamin B₁₂

Although most B-group vitamins are water-soluble and excreted readily in urine, Vitamin B₁₂ is an exception. It is stored in significant amounts in the human liver.

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9. Convulsions in humans can be caused due to the deficiency of which of the following vitamins?

  1. Vitamin B₆
  2. Vitamin B₁
  3. Vitamin B₂
  4. Vitamin B₁₂
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Answer: (A) Vitamin B₆

Deficiency of Vitamin B₆ (Pyridoxine) leads to convulsions as per NCERT Chapter Biomolecules.

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10. Match the vitamins in List-I with their corresponding chemical names in List-II: List-I: (A) Vitamin B₂ (B) Vitamin B₆ (C) Vitamin B₁₂ (D) Vitamin E List-II: (I) Cyanocobalamin (II) Tocopherol (III) Riboflavin (IV) Pyridoxine Choose the correct answer from the options given below:

  1. (A)-(III), (B)-(I), (C)-(IV), (D)-(II)
  2. (A)-(IV), (B)-(III), (C)-(I), (D)-(II)
  3. (A)-(III), (B)-(IV), (C)-(I), (D)-(II)
  4. (A)-(II), (B)-(IV), (C)-(I), (D)-(III)
Show answer and explanation

Answer: (C) (A)-(III), (B)-(IV), (C)-(I), (D)-(II)

According to standard chemical nomenclature of vitamins, Vitamin B₂ is riboflavin, Vitamin B₆ is pyridoxine, Vitamin B₁₂ is cyanocobalamin, and Vitamin E is tocopherol. Hence, (A)-(III), (B)-(IV), (C)-(I), (D)-(II) is the correct match.

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11. Which of the following vitamins contains a sulfur atom incorporated into its heterocyclic ring system?

  1. Riboflavin
  2. Thiamine
  3. Pyridoxine
  4. Retinol
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Answer: (B) Thiamine

Thiamine (Vitamin B₁) consists of a substituted pyrimidine ring joined by a methylene bridge to a substituted thiazole ring. The thiazole ring contains both a sulfur atom and a nitrogen atom.

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12. Osteomalacia, a condition characterized by soft bones and joint pain in adults, is caused by the dietary deficiency of which of the following vitamins?

  1. Vitamin A
  2. Vitamin E
  3. Vitamin K
  4. Vitamin D
Show answer and explanation

Answer: (D) Vitamin D

Vitamin D deficiency causes rickets in growing children and osteomalacia (softening of bones accompanied by joint and bone pain) in adults. It facilitates calcium absorption and deposition in bone matrix.

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