Class 12 Chemistry - WEST-BENGAL
Biomolecules
The Biomolecules chapter in Class 12 Chemistry explores the chemical basis of life, focusing on complex organic molecules that form living systems. West Bengal (WBBSE) students will study carbohydrates, proteins, nucleic acids, vitamins, and lipids. You will learn about the classification, structures, and biological functions of glucose, fructose, amino acids, peptide bonds, DNA, and RNA. This chapter is highly scoring in board exams because it involves direct structural questions, definitions, and biochemical distinctions like the difference between DNA and RNA, or fibrous and globular proteins.
Start Learning FreeKey Concepts
Carbohydrates
Optically active polyhydroxy aldehydes or polyhydroxy ketones, classified as monosaccharides, oligosaccharides, and polysaccharides based on hydrolysis behavior.
Proteins and Amino Acids
Proteins are polymers of alpha-amino acids linked together by peptide bonds. They exist as zwitterions in solution and possess primary, secondary, tertiary, and quaternary structural levels.
Nucleic Acids
Biomolecules responsible for heredity and protein synthesis, consisting of nucleotides made up of a pentose sugar, a nitrogenous base, and a phosphate group (DNA and RNA).
Vitamins
Organic compounds required in small amounts for normal health, growth, and development, classified into fat-soluble (A, D, E, K) and water-soluble (B-group and C) vitamins.
Enzymes
Biocatalysts composed of globular proteins that speed up biochemical reactions in living cells with high specificity and efficiency.
Important Formulas
Board Exam Info
In the West Bengal (WBBSE) Class 12 Chemistry board exam, Biomolecules typically carries around 3 to 5 marks. Questions frequently include short-answer questions (SAQs) defining terms like zwitterion, peptide bond, or denaturation of proteins, alongside differentiating questions such as reducing vs non-reducing sugars and DNA vs RNA.
Frequently Asked Questions
What is a zwitterion and which molecules form it?
A zwitterion is a dipolar ion formed when the acidic carboxyl group and basic amino group of an amino acid transfer a proton internally, resulting in both positive and negative charges on the same molecule.
What is the difference between reducing and non-reducing sugars?
Reducing sugars contain free aldehydic or ketonic groups and can reduce Tollens' or Fehling's solution (e.g., glucose, lactose). Non-reducing sugars have their carbonyl carbons involved in glycosidic bonds and cannot reduce these reagents (e.g., sucrose).
Why are vitamins important and how are they classified?
Vitamins are essential organic micronutrients that our bodies cannot synthesize in sufficient amounts. They are classified based on solubility into fat-soluble (A, D, E, K) and water-soluble (B-complex and C) vitamins.
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