Class 11 Biomolecules (Human physiology physiology) NEET

Unlock a thorough, deep-dive understanding of biochemistry with these comprehensive notes on Biomolecules. Whether you are preparing for Class 11 board exams, aiming for a top rank in NEET, or building a strong foundation for undergraduate Botany and Zoology, these notes provide a complete, line-by-line breakdown of the biological chemistry of living organisms.

Detailed Chapter Breakdown Included

1. Analysis of Chemical Composition

Elemental Analysis: How to analyze plant/animal tissues using trichloroacetic acid (\text{CCl}_3\text{COOH}).

Biomolecular Fractions: Distinction between the acid-soluble pool (micromolecules like amino acids, simple sugars, nucleotides) and the acid-insoluble pool (macromolecules like proteins, nucleic acids, polysaccharides, and lipids).

2. Primary and Secondary Metabolites

Primary Metabolites: Essential compounds involved directly in normal growth, development, and reproduction (e.g., sugars, amino acids, nucleic acids).

Secondary Metabolites: Ecological and economic significance of alkaloids, flavonoids, rubber, essential oils, antibiotics, colored pigments, scents, gums, and lectins (e.g., Concanavalin A).

3. Carbohydrates (Saccharides)

Monosaccharides: Classification based on carbon number (trioses, pentoses, hexoses) and functional groups (aldoses vs. ketoses).

Polysaccharides: Structural and storage polysaccharides:

Starch & Glycogen: Alpha-glucose polymers for energy storage in plants and animals.

Cellulose: Unbranched beta-glucose polymer forming plant cell walls.

Chitin: Structural homopolymer of N-acetylglucosamine (NAG) in fungal cell walls and arthropod exoskeletons.

Glycosidic Bonds: How dehydration synthesis forms links between sugar subunits.

4. Proteins and Amino Acids

Amino Acid Chemistry: Structure of substituted methanes, essential vs. non-essential amino acids, and the formation of zwitterions at specific pH values.

Peptide Bond Formation: Condensation reactions between carboxyl (-\text{COOH}) and amino (-\text{NH}_2) groups.

Protein Structural Levels:

Primary Structure: Linear amino acid sequence.

Secondary Structure: Alpha-helices and beta-pleated sheets stabilized by hydrogen bonds.

Tertiary Structure: 3D folding crucial for biological activity (e.g., enzymes).

Quaternary Structure: Multi-subunit arrangements (e.g., Adult Hemoglobin with 2 alpha and 2 beta chains).

5. Lipids

Simple Lipids: Saturated vs. unsaturated fatty acids (Palmitic acid, Arachidonic acid) esterified with glycerol to form mono-, di-, and triglycerides.

Complex Lipids: Phospholipids (Lecithin) forming biological membranes and glycolipids.

Derived Lipids: Cholesterol, steroids, and lipophilic vitamins.

6. Nucleic Acids

Nucleotides vs. Nucleosides: Purines (Adenine, Guanine) and Pyrimidines (Cytosine, Thymine, Uracil) bonded to ribose or deoxyribose sugars.

Phosphodiester Bonds: Linking 3'-carbon and 5'-carbon of adjacent sugar molecules.

B-DNA Structure: Watson-Crick double helix parameters (pitch, distance between base pairs, hydrogen bonding between A=T and G$\equiv$C).

7. Enzymes & Catalysis

Nature of Enzymes: Tertiary structure, active sites, and activation energy reduction.

Enzyme Kinetics: Michaelis-Menten kinetics, V_{\max}, and K_m values.

Factors Affecting Enzyme Activity: Temperature, pH, and substrate concentration curves.

Enzyme Inhibition:

Competitive Inhibition: Malonate inhibiting succinic dehydrogenase (resembles succinate).

Non-Competitive & Allosteric Inhibition.

IUBMB Classification: Six main classes (Oxidoreductases, Transferases, Hydrolases, Lyases, Isomerases, Ligases).

Cofactors: Prosthetic groups (e.g., Haem in peroxidase), co-enzymes (e.g., NAD/NADP containing Niacin), and metal ion activators (e.g., Zinc for Carboxypeptidase).

Key Features & Benefits

100% NCERT-Aligned: Strictly derived from the latest NCERT Biology textbook.

High-Yield Visuals: Packed with chemical structures, comparative tables, and reaction flowcharts.

Exam-Oriented: Highlights previous years' question (PYQ) concepts, numerical/graphical trends, and tricky exceptions.

Time-Saving Revision: Neatly formatted points ideal for fast final review before exams.