- DNA consists of two polynucleotide strands coiled around each other to form a right-handed double helix.
- The two strands run in opposite directions, one from 5′ to 3′ and the other from 3′ to 5′, making them antiparallel.
- The sugar–phosphate backbone forms the outer framework of the helix, while nitrogenous bases lie inside.
- The two strands are held together by hydrogen bonds between complementary bases.
- Adenine pairs with thymine through two hydrogen bonds, and guanine pairs with cytosine through three hydrogen bonds, making A–T and C–G complementary base pairs.
Topics
Solid State
- Solid State
- Types of Solids
- Classification of Crystalline Solids
- Crystal Structure
- Cubic System
- Packing of Particles in Crystal Lattice
- Packing Efficiency
- Crystal Defects or Imperfections
- Properties of Solids: Electrical Properties
- Overview of Solid State
Solid State
- Introduction to Solid State
- Classification of Crystalline Solids
- Amorphous and Crystalline Solids
- Crystal Lattices and Unit Cells
- Calculations Involving Unit Cell Dimensions
- Close Packed Structures of Solids
- Efficiency of Packing in Body-centred Cubic Structures
- Close Packed Structures - Formula of a Compound and Number of Voids Filled
- Number of Atoms in a Unit Cell
- Imperfections in Solids - Introduction
- Properties of Solids: Magnetic Properties
- Band Theory of Metals
- Properties of Solids: Electrical Properties
- Applications of n-type and p-type Semiconductors
Solutions
- Introduction to Solutions
- Types of Solutions
- Capacity of Solution to Dissolve Solute
- Solubility
- Vapour Pressure of Solutions of Liquids in Liquids
- Colligative Properties of Nonelectrolyte Solutions
- Vapour Pressure Lowering
- Boiling Point Elevation
- Depression in Freezing Point
- Osmosis and Osmotic Pressure
- Colligative Properties of Electrolytes
- Overview of Solutions
Solutions and Colligative Properties
- Types of Solutions
- Expressing Concentration of Solutions
- Solubility of a Gas in a Liquid
- Solubility of a Solid in a Liquid
- Colligative Properties and Determination of Molar Mass - Introduction
- Relative Lowering of Vapour Pressure
- Depression of Freezing Point
- Osmosis and Osmotic Pressure
- Abnormal Molar Masses
- Elevation of Boiling Point
Chemical Thermodynamics and Energetic
- Chemical Thermodynamics and Energetic
- Concepts of System
- Types of Systems
- Surroundings
- Work, Heat, Energy, Extensive and Intensive Properties
- State Functions
- First Law of Thermodynamics
- Internal Energy and Enthalpy
- Hess’ Law of Constant Heat Summation
- Enthalpy of Bond Dissociation
- Combustion, Formation, Atomization, Sublimation
- Phase Transition
- Ionization and Solution
- Dilution Introduction of Entropy as a State Function
- Free Energy Change for Spontaneous and Non Spontaneous Processes
- Equilibrium Constant
- Second and Third Law of Thermodynamics
Ionic Equilibria
- Ionic Equilibria
- Types of Electrolyte
- Acids and Bases in Daily Life
- Ionization of Acids and Bases
- Autoionization of Water
- The pH Scale
- Hydrolysis of Salts
- Buffer Solutions
- Solubility product
- Common Ion Effect
- Overview of Ionic Equilibria
Chemical Thermodynamics
- Chemical Thermodynamics
- Terms Used in Thermodynamics
- Nature of Heat and Work
- Expression for Pressure-volume (PV) Work
- Concept of Maximum Work
- Internal Energy (U)
- First Law of Thermodynamics
- Enthalpy (H)
- Enthalpies of Physical Transformations
- Thermochemistry
- Spontaneous (Irreversible) Process
- Overview of Chemical Thermodynamics
Electrochemistry
- Electrochemical Cells
- Conductance of Electrolytic Solutions - Introduction
- Variation of Conductivity and Molar Conductivity with Concentration
- Electrolytic Cells and Electrolysis - Introduction
- Primary Batteries
- Lead Accumulator
- Galvanic or Voltaic Cells - Introduction
- Nernst Equation - Introduction
- Relation Between Gibbs Energy Change and Emf of a Cell
- fuel cell
- Factors Affecting Corrosion
- Redox Reaction
Electrochemistry
- Electrochemistry
- Electric Conduction
- Electrical Conductance of Solution
- Electrochemical Cells
- Electrolytic Cell
- Galvanic or Voltaic Cell
- Electrode Potential and Cell Potential
- Thermodynamics of Galvanic Cells
- Reference Electrodes
- Galvanic Cells Useful in Day-to-day Life
- Fuel Cells
- Electrochemical Series (Electromotive Series)
- Overview of Electrochemistry
Chemical Kinetics
General Principles and Processes of Isolation of Elements
Chemical Kinetics
- Chemical Kinetics
- Rate of Reactions
- Rate of Reaction and Reactant Concentration
- Molecularity of Elementary Reactions
- Integrated Rate Equations
- First Order Reactions
- Zero Order Reactions
- Half Life Period of a Reaction
- Pseudo First Order Reaction
- Integrated Rate Law for Gas Phase f Reactions
- Collision Theory of Bimolecular Reactions
- Temperature Dependence of Reaction Rates
- Effect of a Catalyst on the Rate of Reaction
- Overview of Chemical Kinetics
P-block Elements
Elements of Groups 16, 17 and 18
- Occurrence of Elements of Groups 16, 17 and 18
- Electronic Configuration of Elements of Group 16, 17 and 18
- Atomic and Physical Properties of Elements of Group 16, 17 and 18
- Anomalous Behaviour of Oxygen
- Anomalous Behaviour of Fluorine
- Chemical Properties of Elements of Groups 16, 17 and 18
- Oxoacids
- Oxygen and Compounds of Oxygen
- Chlorine
- Concept of Group 18 Elements
- Overview of Elements of Groups 16, 17 and 18
Group 15 Elements
Group 16 Elements
Group 17 Elements
- Concept of Group 17 Elements
- Anomalous Behaviour of Fluorine
- Compounds of Halogens
- Chlorine
- Hydrogen Chloride
- Interhalogen Compounds
- Oxoacids of Halogens
Group 18 Elements
Transition and Inner Transition Elements
- Transition and Inner Transition Elements
- Position in the Periodic Table of Transition and Inner Transition Elements
- Electronic Configuration of Transition and Inner Transition Elements
- Oxidation States of First Transition Series
- Physical Properties of First Transition Series
- Trends in Atomic Properties of the First Transition Series
- Preparation of Potassium Permanganate
- Chemical Properties of KMnO4
- Uses of KMnO4
- K2Cr2O7: Preparation of Potassium Dichromate
- Chemical Properties of K2Cr2O7
- Common Properties of d Block Elements
- Basic Principles of Metallurgy > Extraction of Metals
- Inner Transition (f-block) Elements: Lanthanoids and Actinoids
- Properties of f-block Elements
- Properties of Lanthanoids
- Applications of Lanthanoids
- The Actinoids
- Properties of Actinoids
- Applications of Actinoids
- Postactinoid Elements
- Overview of Transition and Inner Transition Elements
D and F Block Elements
D-block Elements
- General Indroduction
- Position in the Periodic Table - d-block Elements
- Electronic Configurations of the D-block Elements
- General Properties of the Transition Elements (D-block)
- Some Important Compounds of Transition Elements
F-block Elements
Coordination Compounds
- Introduction
- Nomenclature of Coordination Compounds - Formulas of Mononuclear Coordination Entities
- Nomenclature of Coordination Compounds - Naming of Mononuclear Coordination Compounds
- Importance of Coordination Compounds
- Definitions of Some Important Terms Pertaining to Coordination Compounds
- Colour in Coordination Compounds
- Magnetic Properties of Coordination Compounds
- Bonding in Coordination Compounds - Introduction
- Werner’s Theory of Coordination Compounds
- Valence Bond Theory (VBT)
- Crystal Field Theory (CFT)
- Stereoisomerism
- Structural Isomerism
- Importance of Coordination Compounds
Coordination Compounds
- Coordination Compounds
- Types of Ligands
- Terms Used in Coordination Chemistry
- Classification of Complexes
- IUPAC Nomenclature of Coordination Compounds
- Effective Atomic Number (EAN) Rule
- Isomerism in Coordination Compounds
- Stability of the Coordination Compounds
- Theories of Bonding in Complexes
- Applications of Coordination Compounds
- Overview of Coordination Compounds
Halogen Derivatives of Alkanes (And Arenes)
Halogen Derivatives
- Classification of Halogen Derivatives
- Nomenclature of Halogen Derivatives
- Methods of Preparation of Alkyl Halides
- Physical Properties
- Optical Isomerism in Halogen Derivatives
- Chemical Properties
- Reaction with Active Metals
- Uses and Environmental Effects of Some Polyhalogen Compounds
- Nomenclature
- Reactions of Haloalkanes - Elimination Reactions
- Overview of Halogen Derivatives
Haloalkanes
- Introduction of Haloalkanes and Haloarenes
- Nomenclature
- Nature of C-X Bond
- Physical Properties of Haloalkanes and Haloarenes
- Methods of Preparation of Haloalkanes and Haloarenes
- Reactions of Haloalkanes - Nucleophilic Substitution Reactions
- Reactions of Haloalkanes - Elimination Reactions
- R-s and D-l Configuration
Haloarenes
- Introduction of Haloalkanes and Haloarenes
- Nature of C-X Bond
- Reactions of Haloarenes - Nucleophilic Substitution
- Nucleophilic Substitution
- Electrophilic Substitution Reactions
- Reaction with Metals
- R-S and D-l Configurations
- Polyhalogen Compounds
Alcohols, Phenols and Ethers Alcohols
Alcohols, Phenols and Ethers
- Alcohols, Phenols and Ethers
- Classification of Alcohols, Phenols and Ethers
- Nomenclature
- Alcohols and Phenols
- Ethers
- Uses of Alcohols, Phenols and Ethers
- Overview of Alcohols, Phenols and Ethers
- Overview: Alcohols, Phenols and Ethers
Alcohols
Phenols
- Phenols
- Nomenclature
- Methods of Preparation
- Physical and Chemical Properties
- Acidic Nature of Phenol
- Electrophillic Substitution Reactions
- Uses of Phenols
Ethers
Aldehydes, Ketones and Carboxylic Acids
Aldehydes, Ketones and Carboxylic Acids
- Introduction of Aldehydes, Ketones and Carboxylic Acids
- Classification of Aldehydes, Ketones and Carboxylic Acids
- Nomenclature of Aldehydes, Ketones and Carboxylic Acids
- Preparation of Aldehydes and Ketones
- Preparation of Carboxylic Acids
- Physical Properties
- Polarity of Carbonyl Group
- Chemical Properties of Aldehydes and Ketones
- Chemical Properties of Carboxylic Acids
- Chemical Reactions of Aldehydes and Ketones - Reactions Due to α-hydrogen
- Overview: Aldehydes, Ketones and Carboxylic Acids
- Overview of Aldehydes, Ketones and Carboxylic Acids
Aldehydes and Ketones
- Introduction of Aldehydes, Ketones and Carboxylic Acids
- Nomenclature of Aldehydes and Ketones
- Nature of Carbonyl Group
- Preparation of Aldehydes and Ketones
- Physical Properties of Aldehydes and Ketones
- Chemical Reactions of Aldehydes and Ketones - Nucleophilic Addition Reactions
- Reactivity of Alpha Hydrogen in Aldehydes
- Uses of Aldehydes and Ketones
- Chemical Reactions of Aldehydes and Ketones - Other Reactions
Carboxylic Acids
- Carboxylic Acids
- Nomenclature of Carboxylic Acids
- Structure of the Carboxyl group
- Methods of Preparation of Carboxylic Acids
- Physical Properties of Carboxylic Acids
- Chemical Properties and Reactions of Carboxylic Acid
- Chemical Reactions of Carboxylic Acids - Reactions Involving Cleavege of O-H Bond
- Chemical Reactions of Carboxylic Acids - Reactions Involving Cleavege of C-OH Bond
- Chemical Reactions of Carboxylic Acids - Reactions Involving –COOH Group
- Chemical Reactions of Carboxylic Acids - Substitution Reactions in the Hydrocarbon Part
- Uses of Carboxylic Acids
Organic Compounds Containing Nitrogen
Amines
- Classification of Amines
- Nomenclature of Amines
- Preparation of Amines
- Physical Properties of Amines
- Basicity of Amines
- Chemical Properties of Amines
- Reactions of Arene Diazonium Salts
- Reaction with Arenesulfonyl Chloride
- Electrophilic Aromatic Substitution in Aromatic Amines
- Overview of Amines
Amines
- Introduction of Amines
- Nomenclature of Animes
- Classification of Amines
- Structure of Amines
- Physical Properties of Amines
- Uses of Amines
- Identification of Primary, Secondary and Tertiary Amines
- Secondary and Tertiary Amines
- Chemical Reactions of Amines - Carbylamine Reaction
- Chemical Reactions of Amines - Reaction with Nitrous Acid
- Chemical Reactions of Amines - Reaction with Arylsulphonyl Chloride
- Chemical Reactions of Amines - Electrophilic Substitution
- Preparation of Amines
Cyanides and Isocyanides
Diazonium Salts
Biomolecules
Biomolecules
- Principal Molecules of the Living World
- Biomolecules in the Cell > Carbohydrates
- Biomolecules in the Cell > Proteins
- Overview of Biomolecules
- Overview: Biomolecules
Carbohydrates
Proteins
- Introduction of Proteins
- Amino Acids
- Peptide
- Linkage
- Polypeptides
- Structure of Proteins
- Biomolecules in the Cell > Enzymes
- Lipids and Hormones
- Structure, Classification and Functions
Vitamins
- Introduction of Vitamins
- Classification of Vitamins
- Important Vitamins, Their Sources and Their Deficiency Diseases
Nucleic Acids
Polymers
- Introduction to Polymers
- Classification of Polymers Based on Source
- Types of Polymerisation Reactions - Addition Polymerisation or Chain Growth Polymerisation
- Types of Polymerisation Reactions - Copolymerisation
- Some Important Polymers
- Types of Polymerisation Reactions - Condensation Polymerisation Or Step Growth Polymerisation
- Nylon 6
- Nylon 66
- Types of Polymerisation Reactions - Rubber
- Biodegradable Polymers
- Preparation of Polytetrafluoroethene (Teflon)
- Preparation of Polyacrylonitrile
Introduction to Polymer Chemistry
- Introduction to Polymer Chemistry
- Classification of Polymers
- Some Important Polymers
- Molecular Mass and Degree of Polymerization of Polymers
- Biodegradable Polymers
- Commercially Important Polymers
- Preparation of Polytetrafluoroethene (Teflon)
- Overview of Introduction to Polymer Chemistry
Chemistry in Everyday Life
Green Chemistry and Nanochemistry
- Green Chemistry and Nanochemistry
- Principles of Green Chemistry
- The Role of Green Chemistry
- Introduction to Nanochemistry
- Characteristic Features of Nanoparticles
- Synthesis of Nanomaterials
- History of Nanotechnology
- Applications of Nanomaterials
- Nanoparticles and Nanotechnology
- Overview of Green Chemistry and Nanochemistry
Chemicals in Medicines
Chemicals in Food
Cleansing Agents
Estimated time: 14 minutes
Maharashtra State Board: Class 12
Key Points: Structure of Proteins
| Feature | Primary Structure | Secondary Structure | Tertiary Structure | Quaternary Structure |
|---|---|---|---|---|
| Meaning | The linear sequence of amino acid residues linked by peptide bonds is called primary structure of protein. | The regular local folding of the polypeptide chain into specific patterns is called secondary structure of protein. | The overall three-dimensional folding of a single polypeptide chain is called tertiary structure of protein. | The spatial arrangement formed by association of two or more polypeptide chains is called quaternary structure of protein. |
| Structural Description | Specific order of amino acids from N-terminal to C-terminal. | Organized into α-helix or β-pleated sheet patterns. | Compact globular or fibrous three-dimensional form. | Multiple folded subunits assembled into one functional unit. |
| Main Bonds / Forces Involved | Peptide bonds (–CO–NH–). | Hydrogen bonding between C=O and N–H groups. | Hydrogen bonds, ionic bonds, disulfide bonds, dipole interactions and London forces. | Same intermolecular forces acting between different subunits. |
| Stability Features | Determines identity and properties of protein. | Provides backbone stabilization. | Stabilized by side-chain interactions. | Necessary for functional activity of certain proteins. |
| Example | Amino acid sequence notation. | α-helix in keratin; β-sheet in silk. | Many enzymes and globular proteins. | Haemoglobin (four subunits). |
Maharashtra State Board: Class 12
