Class 12 Chemistry - KARNATAKA
Biomolecules
The chapter 'Biomolecules' in Class 12 Chemistry explores the chemical basis of life, focusing on the structure, classification, and biological functions of vital organic compounds. Students will study carbohydrates (glucose, fructose, starch, cellulose), proteins (amino acids, peptide bonds, structures of proteins), nucleic acids (DNA and RNA, nucleotides), vitamins, and hormones. This chapter is exceptionally important for Karnataka (KSEEB) board exams as it bridges organic chemistry with biology, frequently featuring direct structural diagrams, classification questions, and structural difference queries. Mastering this chapter ensures scoring high in both theoretical and application-based questions.
Start Learning FreeKey Concepts
Carbohydrates
Optically active polyhydroxy aldehydes or polyhydroxy ketones, classified as monosaccharides, oligosaccharides, and polysaccharides based on hydrolysis behavior.
Amino Acids and Proteins
Proteins are polymers of alpha-amino acids linked by peptide bonds. They exhibit primary, secondary, tertiary, and quaternary structural levels essential for biological function.
Nucleic Acids
Biopolymers like DNA and RNA made of nucleotide units (pentose sugar, nitrogenous base, and phosphate group) responsible for heredity and protein synthesis.
Vitamins
Organic compounds required in small amounts for normal health, growth, and metabolism, categorized into water-soluble (B, C) and fat-soluble (A, D, E, K) vitamins.
Enzymes
Biological catalysts, primarily globular proteins, that speed up biochemical reactions with high specificity and efficiency.
Important Formulas
Board Exam Info
In the Karnataka (KSEEB) Class 12 Chemistry board exam, Biomolecules typically carries around 4 to 6 marks. Questions usually include 1-mark objective questions, 2-mark definitions or structural differences (e.g., reducing vs non-reducing sugars, DNA vs RNA), and 3-mark descriptive questions on protein structures or vitamin deficiencies.
Frequently Asked Questions
Reducing sugars contain free aldehydic or ketonic groups and reduce Fehling's and Tollens' reagents (e.g., glucose, lactose). Non-reducing sugars do not have free functional groups as their carbonyl carbons are involved in glycosidic bond formation (e.g., sucrose).
A Zwitter ion is a dipolar ion formed when an amino acid transfers a proton from its carboxyl group to its amino group, resulting in both positive and negative charges on the same molecule.
Vitamins C and B complex are water-soluble, meaning they dissolve in water and are regularly excreted through urine, so they cannot be stored in the body and must be supplied regularly through diet.
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