Class 12 Chemistry - TAMILNADU
Biomolecules
The Biomolecules chapter in Class 12 Chemistry under the Tamil Nadu Samacheer Kalvi syllabus explores the chemical basis of life. Students will study the structure, classification, and biological importance of carbohydrates, proteins, nucleic acids, vitamins, and lipids. Understanding these molecules is crucial as they form the building blocks of living organisms and play vital roles in metabolic processes. This chapter is a high-scoring section in the Tamil Nadu board exams, frequently featuring direct questions on structures, peptide bonds, glycosidic linkages, and the difference between DNA and RNA, making thorough preparation essential for scoring high marks.
Start Learning FreeKey Concepts
Carbohydrates
Optically active polyhydroxy aldehydes or ketones, classified into monosaccharides, oligosaccharides, and polysaccharides based on hydrolysis behavior.
Proteins and Amino Acids
Polymers of alpha-amino acids linked together by peptide bonds, essential for body growth and repair, existing in primary, secondary, tertiary, and quaternary structures.
Nucleic Acids
Biomolecules such as DNA and RNA responsible for heredity and protein synthesis, composed of a pentose sugar, nitrogenous base, and phosphate group.
Vitamins
Organic compounds required in small amounts for normal health and growth, classified into fat-soluble (A, D, E, K) and water-soluble (B-complex and C) vitamins.
Enzymes
Biological catalysts produced by living cells, mostly globular proteins, that speed up specific biochemical reactions without being consumed.
Important Formulas
Board Exam Info
In the Tamil Nadu (Samacheer Kalvi) Class 12 Chemistry board exam, Biomolecules typically carries around 4 to 6 marks. Questions frequently include 1-mark objective questions, 2-mark definitions (like peptide bond or zwitter ion), 3-mark structural differences (DNA vs RNA), and 5-mark classifications or structural elucidation questions.
Frequently Asked Questions
What is the difference between alpha-D-glucose and beta-D-glucose?
They are anomers that differ only in the configuration of the hydroxyl group (-OH) at C-1 carbon atom (anomeric carbon).
Why are vitamin C and B-complex vitamins not stored in our body?
Because they are water-soluble vitamins, excess amounts are readily excreted through urine and cannot be stored in the body, requiring regular dietary intake.
What is a peptide bond and how is it formed?
A peptide bond is an amide linkage (-CO-NH-) formed by the reaction between the carboxyl group of one amino acid and the amino group of another amino acid with the elimination of a water molecule.
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