Lecture Notes on Biomolecules and Enic Acid from Victory Batch Lecture

Introduction

• Title: Biomolecules and Enzymes
• Presented by: Dikshaman
• Importance: Critical chapter for understanding molecules in living systems, both organic and inorganic.

Biomolecules

Definition

• Biomolecules: Molecules present in living organisms, can be organic or inorganic, usually organic.

Composition Analysis

• Experiment: Grinding liver tissue in trichloroacetic acid to form slurry, split into retentate (larger, acid-insoluble molecules) and filtrate (smaller, acid-soluble molecules).
• Classification by size:
  • Bio-micro molecules: <1000 Dalton (simple sugars, amino acids, nucleotides)
  • Bio-macro molecules: >10,000 Dalton (proteins, nucleic acids)
• Lipid Controversy: Lipids are treated as macromolecules but have weights <800 Dalton due to the formation of vesicles.

Inorganic Elements

• Ash Analysis Experiment: Tissue burned to ash to study inorganic elements like sodium, potassium, calcium, magnesium.
• Functions:
  • Sodium & Potassium: Nerve impulse, electrolyte balance
  • Calcium: Blood clotting, bone formation, muscle contraction
  • Magnesium: Enzyme cofactor
  • Buffers: Maintain pH balance

Comparison with Earth’s Crust

• Learning the differences in element composition between humans and Earth's crust.

Metabolites

• Definition: Organic molecules participating in metabolism.
• Classification:
  • Primary Metabolites: Essential for survival (e.g., chlorophyll)
  • Secondary Metabolites: Non-essential but beneficial (e.g., pigments, alkaloids)

Carbohydrates

Definition

• Compounds with carbon, hydrogen, oxygen in 2:1 (H:O) ratio.
• Known as sugars or saccharides.

Structure

• Glucose (C6H12O6): Draw six carbon chains:
  • Linear form: aldehyde group, polyhydroxy aldoses (glucose) or ketosis (fructose).
  • Cyclic form: alpha (OH below) and beta (OH above).

Derived Monosaccharides

• Deoxyribose (DNA) derived from ribose (RNA) by removing an oxygen.

Disaccharides

• Formation: Two sugars join via glycosidic bond (e.g., Maltose, Lactose, Sucrose).
• Reducing vs. Non-Reducing Sugars: Felling Benedict test to determine.

Polysaccharides

• Types: Homo (single sugar type) & Heteropolysaccharides (multiple sugar types).
• Examples:
  • Storage polysaccharides (e.g., Starch, Glycogen).
  • Structural polysaccharides (e.g., Cellulose, Chitin).
  • Derived polysaccharides (e.g., Inulin).

Amino Acids and Proteins

Amino Acids

• Structure: Substituted methane with amino and carboxyl groups.
• Classification: Neutral, acidic, basic, alcoholic, sulfur-containing, aromatic, heterocyclic.
• Polarity: Non-polar, polar charged, polar uncharged.
• Essentiality: Essential, semi-essential, non-essential.

Proteins

• Polymers: Made of 20 different amino acids.
• Structure Levels: Primary, secondary (alpha-helix, beta-pleated), tertiary, quaternary.
• Functions: Structural (collagen), catalytic (enzymes), hormonal (insulin), transport (glut4), etc.

Lipids

Types

• Simple Lipids: Fatty acids esterified with glycerol (e.g., True fats, Waxes).
• Compound Lipids: Fatty acids plus additional groups (e.g., Phospholipids - Lecithin).
• Derived Lipids: Modified fatty acids (e.g., Steroids - Cholesterol, Prostaglandins).

Characteristics

• Insoluble in water, soluble in organic solvents.
• Functions include energy storage, insulation, cell membrane formation.

Nucleic Acids

Types of Nucleic Acids

• DNA: Deoxyribonucleic acid, double-stranded helix, antiparallel, genetic material.
• RNA: Ribonucleic acid, single-stranded, involved in protein synthesis (mRNA, tRNA, rRNA).

Structural Units

• Nucleotides: Made up of a sugar, phosphate group, and nitrogenous base (A, T, G, C in DNA; A, U, G, C in RNA).
• Structural details including phosphodiester bonds, hydrogen bonding between bases.

Enzymes

Functions

• Biological catalysts made of proteins, speed up reactions by lowering activation energy (e.g., Carbonic anhydrase).
• Structure: Defined by active site and allosteric site.

Factors Affecting Enzyme Activity

• Temperature: Optimal range, high temperatures lead to denaturation.
• pH: Each enzyme has an optimal pH.
• Substrate Concentration: Reaction rate increases with substrate concentration to an extent (Michaelis-Menten kinetics).
• Inhibitors: Competitive (bind to active site) and non-competitive (bind to allosteric site).
• Cofactors: Non-protein molecules needed for enzyme activity (e.g., vitamins, metal ions).

Conclusion

• Biomolecules play crucial roles in living organisms, contributing to structure, function, and regulation of biological processes.
• Enzymes are essential for facilitating and regulating biochemical reactions in the body.