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Biomolecules - Vitamins (Classification and Functions)

Grade 12CBSEChemistry

Review the key concepts, formulae, and examples before starting your quiz.

🔑Concepts

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Vitamins are organic compounds required in the diet in small amounts to perform specific biological functions for normal maintenance of optimum growth and health of the organism.

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Classification based on solubility: Fat-soluble vitamins (Vitamins A,D,E,A, D, E, and KK) are soluble in fats and oils but insoluble in water. They are stored in liver and adipose (fat storing) tissues.

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Water-soluble vitamins: Vitamins of BB group (B1,B2,B6,B12B_1, B_2, B_6, B_{12}, etc.) and Vitamin CC are soluble in water. They must be supplied regularly in diet because they are readily excreted in urine and cannot be stored (except Vitamin B12B_{12}) in our body.

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Vitamin HH (Biotin) is an exception as it is neither soluble in water nor in fat.

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Important Vitamins and Deficiency Diseases: Vitamin AA (Xerophthalmia/Night blindness), Vitamin B1B_1 (Beri-beri), Vitamin B2B_2 (Cheilosis), Vitamin B12B_{12} (Pernicious anaemia), Vitamin CC (Scurvy), Vitamin DD (Rickets/Osteomalacia), Vitamin EE (Increased fragility of RBCs/Muscular weakness), Vitamin KK (Increased blood clotting time).

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Vitamin CC is chemically known as Ascorbic Acid (C6H8O6C_6H_8O_6) and is found mainly in citrus fruits.

📐Formulae

C6H8O6 (Vitamin C / Ascorbic Acid)C_6H_8O_6 \text{ (Vitamin C / Ascorbic Acid)}

C20H30O (Vitamin A / Retinol)C_{20}H_{30}O \text{ (Vitamin A / Retinol)}

C63H88CoN14O14P (Vitamin B12 / Cyanocobalamin)C_{63}H_{88}CoN_{14}O_{14}P \text{ (Vitamin B}_{12} \text{ / Cyanocobalamin)}

C28H44O (Vitamin D2 / Ergocalciferol)C_{28}H_{44}O \text{ (Vitamin D}_2 \text{ / Ergocalciferol)}

💡Examples

Problem 1:

Why cannot Vitamin CC be stored in our body?

Solution:

Vitamin CC is a water-soluble vitamin.

Explanation:

Because it is soluble in water, it is readily excreted from the body through urine and is not stored in the liver or adipose tissues like fat-soluble vitamins. Therefore, it must be supplied regularly in the diet.

Problem 2:

Name the vitamin whose deficiency causes 'Pernicious Anaemia' and mention its unique metallic constituent.

Solution:

Vitamin B12B_{12} (Cyanocobalamin); Central metal atom: CoCo (Cobalt).

Explanation:

Vitamin B12B_{12} is essential for the maturation of Red Blood Cells (RBCsRBCs). Its deficiency leads to a decrease in RBCsRBCs, a condition known as pernicious anaemia. It contains a coordination complex of Cobalt (Co3+Co^{3+}).

Problem 3:

A person is suffering from the lengthening of blood clotting time. Which vitamin deficiency is likely responsible?

Solution:

Vitamin KK (Phylloquinone).

Explanation:

Vitamin KK is essential for the synthesis of prothrombin and other clotting factors in the liver. A deficiency of Vitamin KK results in a decrease in these factors, leading to delayed blood coagulation and increased bleeding tendencies.