The study of biomolecules forms the chemical foundation of biology. These are complex organic molecules that make up living organisms, driving essential life processes such as metabolism, growth, reproduction, and heredity. From proteins that build our tissues to DNA that carries genetic information, biomolecules are the very essence of life. For NEET, AIIMS, and other biology-focused exams, this chapter is crucial, as it connects chemistry with zoology.
Introduction to Biomolecules
Biomolecules are organic and inorganic compounds present in all living cells. They can be broadly divided into two categories:
1. Micromolecules – Small molecules with low molecular weight (e.g., water, minerals, amino acids).These biomolecules not only provide structure but also regulate functions and act as energy sources.
Major Types of Biomolecules
Carbohydrates
Carbohydrates are the primary energy source for living cells. They are composed of carbon, hydrogen, and oxygen, usually in the ratio (CH₂O)ₙ.
- Monosaccharides – Single sugar units like glucose, fructose, galactose.
- Disaccharides – Two monosaccharides linked together (sucrose, lactose, maltose).
- Polysaccharides – Long chains of sugars such as starch, glycogen, cellulose, and chitin.
Proteins
Proteins are polymers of amino acids linked by peptide bonds. They perform structural, enzymatic, transport, and hormonal functions.
- Structural proteins: keratin, collagen
- Enzymes: amylase, DNA polymerase
- Hormones: insulin, glucagon
- Antibodies: immunoglobulins
Lipids
Lipids are hydrophobic biomolecules, insoluble in water but soluble in organic solvents.
- Simple lipids: fats, oils, waxes
- Complex lipids: phospholipids, glycolipids
- Derived lipids: steroids (cholesterol, testosterone, estrogen)
Lipids act as energy reserves, form membranes, and regulate signaling pathways.
Nucleic Acids
Nucleic acids store and transmit genetic information. They are polymers of nucleotides, each containing a sugar, phosphate group, and nitrogenous base.
- DNA (Deoxyribonucleic acid) – Stores hereditary information.
- RNA (Ribonucleic acid) – Involved in protein synthesis (mRNA, tRNA, rRNA).
Vitamins and Minerals
Though required in small amounts, they are essential biomolecules for enzymatic activity and proper metabolic functioning.
- Fat-soluble vitamins: A, D, E, K
- Water-soluble vitamins: B-complex, C
- Minerals: Calcium, Iron, Sodium, Potassium, Magnesium
Importance of Biomolecules in Living Systems
- Energy Metabolism – Carbohydrates and lipids serve as fuel.
- Structural Role – Proteins and polysaccharides provide structural integrity.
- Genetic Role – DNA and RNA ensure heredity and protein synthesis.
- Regulatory Role – Hormones and vitamins regulate biological processes.
- Defense Mechanism – Antibodies protect against pathogens.
Biomolecules in NEET and Competitive Exams
This chapter is a high-scoring area in NEET Biology because it combines conceptual understanding with direct fact-based learning. Students often face questions on:
- Structure and function of proteins, carbohydrates, lipids
- Differences between DNA and RNA
- Role of enzymes in metabolism
- Vitamin deficiencies and associated diseases
Comparative Table of Biomolecules
| Biomolecule | Building Blocks | Major Function | Example |
|---|---|---|---|
| Carbohydrates | Monosaccharides | Energy source, storage | Glucose, Starch |
| Proteins | Amino acids | Structural, enzymatic, regulatory | Keratin, Enzymes |
| Lipids | Fatty acids, glycerol | Membrane structure, energy storage | Phospholipids, Steroids |
| Nucleic Acids | Nucleotides | Genetic information, protein synthesis | DNA, RNA |
FAQs on Biomolecules
Q1. What are biomolecules made of?
Biomolecules are made up of carbon, hydrogen, oxygen, nitrogen, and sometimes phosphorus and sulfur.
Q2. What is the difference between DNA and RNA?
DNA is double-stranded and stores genetic information, while RNA is single-stranded and involved in protein synthesis.
Q3. Which biomolecule is the most abundant in the human body?
Proteins are the most abundant macromolecules in human cells.
Q4. What role do vitamins play as biomolecules?
Vitamins act as coenzymes, helping enzymes perform metabolic reactions efficiently.
Q5. Why are biomolecules important for NEET exam preparation?
Biomolecules are frequently tested in NEET through questions on enzymes, nucleic acids, and vitamin deficiencies.