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Biomolecules - Vitamins: Classification and deficiency

Grade 12ICSEChemistry

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: 1. Fat-soluble vitamins (Vitamins AA, DD, EE, and KK) which are stored in liver and adipose tissues. 2. Water-soluble vitamins (B-group vitamins and Vitamin CC) which must be supplied regularly in diet as they are readily excreted in urine and cannot be stored (except Vitamin B12B_{12}).

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Vitamin AA (Retinol) deficiency leads to Xerophthalmia (hardening of cornea) and Night blindness.

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Vitamin B1B_1 (Thiamine) deficiency causes Beri-beri (loss of appetite, retarded growth).

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Vitamin B2B_2 (Riboflavin) deficiency causes Cheilosis (fissuring at corners of mouth and lips).

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Vitamin B12B_{12} (Cyanocobalamin) deficiency causes Pernicious anaemia (RBC deficiency in haemoglobin).

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Vitamin CC (Ascorbic acid) deficiency causes Scurvy (bleeding gums).

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Vitamin DD (Calciferol) deficiency causes Rickets in children (bone deformities) and Osteomalacia in adults (soft bones and joint pain).

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Vitamin KK (Phylloquinone) deficiency increases the time taken for blood clotting.

📐Formulae

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

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

Fat Soluble∈{A,D,E,K}\text{Fat Soluble} \in \{A, D, E, K\}

Water Soluble∈{B-complex,C}\text{Water Soluble} \in \{B\text{-complex}, C\}

💡Examples

Problem 1:

Why cannot Vitamin CC be stored in our body?

Solution:

Vitamin CC is a water-soluble vitamin.

Explanation:

Because Vitamin CC is water-soluble, it is readily excreted in urine and cannot be stored in the body (except in very small amounts). Therefore, it must be supplied regularly through diet.

Problem 2:

Name the vitamin whose deficiency causes Pernicious anaemia and mention its central metal atom.

Solution:

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

Explanation:

Vitamin B12B_{12} is unique among vitamins as it contains a complexed metal ion, Cobalt (Co3+Co^{3+}), in a corrin ring structure.

Problem 3:

A patient presents with bleeding gums and delayed wound healing. Which vitamin deficiency is likely, and what is its chemical name?

Solution:

Vitamin CC; Chemical name: Ascorbic acid.

Explanation:

Scurvy is characterized by the breakdown of collagen, leading to bleeding gums and poor wound healing, caused by a lack of C6H8O6C_6H_8O_6.