Biomolecules: The Building Blocks of Life
Biomolecules are essential organic molecules that make up living organisms. These
molecules play a crucial role in structure, function, and metabolism. The four major types of
biomolecules are carbohydrates, proteins, lipids, and nucleic acids.
1. Carbohydrates: The Energy Providers
✅ Composition: Carbon (C), Hydrogen (H), Oxygen (O) (Ratio: 1:2:1)
✅ Function: Provide energy, structural support, and storage.
✅ Types:
Monosaccharides (single sugar units) – e.g., glucose, fructose, ribose
Disaccharides (two sugar units) – e.g., sucrose (glucose + fructose), lactose
Polysaccharides (many sugar units) – e.g., starch (plants), glycogen (animals),
cellulose (plant cell walls)
📌 Key Formula:
Cn(H2O)n\text{C}_n(\text{H}_2\text{O})_nCn(H2O)n
Example: Glucose (C₆H₁₂O₆)
2. Proteins: The Structural & Functional Molecules
✅ Composition: Made up of amino acids linked by peptide bonds.
✅ Function: Enzymes, structural support, transport, immune defense.
✅ Structure Levels:
Primary Structure – Amino acid sequence
Secondary Structure – Alpha-helix, beta-sheet (H-bonds)
Tertiary Structure – 3D folding (ionic, hydrophobic, disulfide bonds)
Quaternary Structure – Multiple polypeptides joined
📌 Example:
Enzymes: Catalase, Amylase
Structural Proteins: Keratin (hair), Collagen (connective tissue)
3. Lipids: The Hydrophobic Energy Reserves
✅ Composition: Carbon (C), Hydrogen (H), Oxygen (O) (but in no fixed ratio)
✅ Function: Long-term energy storage, insulation, membrane formation.
✅ Types:
Simple Lipids – Fats & oils (triglycerides)
Complex Lipids – Phospholipids (membrane component)
Steroids – Cholesterol, hormones (testosterone, estrogen)
📌 Key Formula (Triglyceride):
Glycerol+3 Fatty Acids→Triglyceride+Water\text{Glycerol} + 3 \text{ Fatty Acids} \
rightarrow \text{Triglyceride} + \text{Water}Glycerol+3 Fatty Acids→Triglyceride+Water
💡 Saturated fats (butter) = no double bonds.
💡 Unsaturated fats (olive oil) = double bonds present.
4. Nucleic Acids: The Genetic Information Carriers
✅ Composition: Made of nucleotides (Sugar + Phosphate + Nitrogenous Base)
✅ Function: Store and transfer genetic information.
✅ Types:
DNA (Deoxyribonucleic Acid) – Genetic blueprint, double-stranded, bases: A-T, G-C
RNA (Ribonucleic Acid) – Helps in protein synthesis, single-stranded, bases: A-U, G-C
📌 Key Structure of a Nucleotide:
Phosphate+Pentose Sugar+Nitrogen Base\text{Phosphate} + \text{Pentose Sugar} + \
text{Nitrogen Base}Phosphate+Pentose Sugar+Nitrogen Base
💡 DNA is more stable (double-stranded, deoxyribose), RNA is more flexible (single-
stranded, ribose).
5. Enzymes: The Biological Catalysts
✅ Function: Speed up biochemical reactions without being consumed.
✅ Lock and Key Model: Enzyme + Substrate → Enzyme-Substrate Complex → Product
✅ Factors Affecting Activity: pH, temperature, enzyme concentration, inhibitors.
📌 Examples:
Amylase – Breaks starch into maltose
Pepsin – Digests proteins in the stomach
6. Vitamins: Essential Organic Compounds
✅ Water-Soluble Vitamins: B-complex, C
✅ Fat-Soluble Vitamins: A, D, E, K
📌 Examples:
Vitamin C (Ascorbic Acid) – Prevents scurvy
Vitamin D – Helps calcium absorption, prevents rickets
7. Hormones: The Chemical Messengers
✅ Peptide Hormones: Insulin, Glucagon (protein-based)
✅ Steroid Hormones: Testosterone, Estrogen (lipid-based)
✅ Thyroid Hormones: T3, T4 (iodine-based)
💡 Hormones regulate metabolism, growth, reproduction, and homeostasis.
Conclusion
Biomolecules are essential for life, providing energy (carbohydrates & lipids), structure
(proteins), genetic information (nucleic acids), and regulation (enzymes, vitamins, and
hormones). A balance of these biomolecules is crucial for a healthy, functioning body.
