Topics
Matter in Our Surroundings
- Matter (Substance)
- Characteristics of Particles (Molecules) of Matter
- The Solid State
- The Liquid State
- The Gaseous State
- Plasma
- Bose-einstein Condensate
- Change of State
- Concept of Evaporation
- Concept of Melting (Fusion)
- Vaporisation or Boiling
- Sublimation
- Concept of Freezing (Solidification)
- Concept of Condensation (Liquefaction)
- Concept of Desublimation (Deposition)
Is Matter Around Us Pure
- Matter (Substance)
- Natural substances
- Mixture
- Types of Mixtures
- Introduction to Solutions
- Concentration of a Solution
- Suspension Solution
- Colloidal Solution
- Evaporation Method
- Solvent Extraction (Using a Separating Funnel Method)
- Sublimation
- Chromatography Method
- Simple Distillation Method
- Fractional Distillation Method
- Crystallisation Method
- Classification of Change: Physical Changes
- Chemical Reaction
- Pure Substances
- Compound
- Elements
Atoms and Molecules
- History of Atom
- Laws of Chemical Combination
- Law of Conservation of Mass
- Law of Constant Proportions (Law of Definite Proportions)
- Dalton's Atomic Theory
- Atoms: Building Blocks of Matter
- Symbols Used to Represent Atoms of Different Elements
- Atomic Mass
- Relative Atomic Mass (RAM)
- Molecules
- Classification of Molecules
- Difference Between Atoms and Molecules
- Ions (Radicals) and Its Types
- Chemical Formula or Molecular Formula
- Molecular Mass
- Formula Unit Mass
- Mole Concept
- Atoms and Molecules Numericals
Structure of the Atom
- Existence of Charged Particles in Matter
- Atoms: Building Blocks of Matter
- Discovery of Charged Particles in Matter
- Protons (p)
- Electrons (e)
- Neutrons (n)
- J. J. Thomson’s Atomic Model
- Advantage and Limitations of Thomson’s Atomic Model
- Lord Rutherford’s Atomic model
- Limitations of Rutherford’s Atomic Model
- Neils Bohr’s Model of an Atom
- Electronic Configuration of Atom
- Periodic Trends in the Modern Periodic Table
- Different Ways to Determine Valency
- Atomic Number (Z) and Mass Number (A)
- Atomic Mass
- Uses of Radioactive Isotopes
- Isotopes
- Atoms and Molecules Numericals
The Fundamental Unit of Life
- The Invention of the Microscope and the Discovery of Cell
- Cell Theory
- Prokaryotic and Eukaryotic Cell
- Cell Organelles
- Structure of the Cell > Plasma Membrane / Cell Membrane
- Structure of the Cell > Cell Wall: “Supporter and Protector”
- Structure of the Cell > Nucleus: “Brain” of the Cell
- Structure of the Cell > Cytoplasm: “Area of Movement”
- Endoplasmic Reticulum (ER)
- Golgi Apparatus - "The delivery system of the cell"
- Lysosome - “Suicidal Bag”
- Mitochondria - “Power House of the Cell”
- Plastids
- Non-living Substances Or Cell Inclusion
- Plant Cell Vs Animal Cell
- Cell Division: an Essential Life Process
Tissues
- Tissues - “The Teams of Workers”
- Plant and Animals Tissue
- Plant Tissues
- Meristems or Meristematic Tissues
- Permanent Tissue
- Simple Permanent Tissues (Supporting Tissue)
- Complex Permanent Tissues
- Complex Permanent Tissue: Xylem Structure and Function (Conducting Tissue)
- Complex Permanent Tissue: Phloem Structure and Function (Conducting Tissue)
- Animal Tissues
- Epithelial Tissue
- Connective Tissue
- Muscular Tissue
- Nervous Tissue
Diversity in Living Organisms
- Introduction of Biological Classification
- Classification of Living Organisms
- Taxonomic Hierarchy of Living Organisms: Unit of Classification
- Five Kingdom Classification
- Kingdom Monera
- Kingdom Protista
- Kingdom Fungi
- Kingdom Plantae
- Kingdom Animalia
- Differences Between Plantae (Plants) and Animalia (Animals)
- Kingdom Plantae
- Sub-division Algae
- Kingdom Plantae: Thallophyta (Fungi)
- Cryptogams > Division II- Bryophytes
- Cryptogams > Division III- Pteridophytes
- Phanerogams > Division I-Gymnosperms
- Phanerogams > Division II- Angiosperms
- Kingdom Animalia
- Phylum: Porifera
- Phylum: Cnidaria/Coelenterata
- Phylum: Platyhelminthes
- Invertebrate: Phylum Nematoda
- Phylum: Annelida
- Phylum: Arthropoda
- Phylum: Mollusca
- Phylum: Echinodermata
- Subphylum: Prochordata
- Subphylum: Vertebrata/Craniata
- Invertebrata and Vertebrata
- Taxonomy and Systematics
- Nomenclature
Motion
- Force and Motion
- Describing Motion
- Motion Along a Straight Line
- Types of Motion
- Measuring the Rate of Motion - Speed with Direction
- Rate of Change of Velocity
- Distance and Displacement
- Displacement - Time Graph Or Distance - Time Graph
- Velocity - Time Graphs
- Equations of Motion by Graphical Method
- Derivation of Velocity - Time Relation by Graphical Method
- Derivation of Displacement - Time Relation by Graphical Method
- Derivation of Displacement - Velocity Relation by Graphical Method
- Uniform Circular Motion (UCM)
- Motion (Numerical)
Force and Laws of Motion
Gravitation
Work and Energy
Sound
- Sound Waves
- Production of Sound
- Propagation of Sound
- Sound Need a Medium to Travel
- Sound Waves Are Longitudinal Waves
- Characteristics of Sound
- Speed of Sound (Velocity of Sound)
- Reflection of Sound Waves
- Echo
- Reverberation
- Uses of Multiple Reflection of Sound
- Range of Hearing in Humans
- Ultrasonic Sound Or Ultrasound
- SONAR
- Sound (Numerical)
Improvement in Food Resources
- Improvements in Food Resources
- Improvement in Crop Yields
- Crop Variety Improvement
- Crop Production Improvement
- Crop Protection Management
- Methods to Replenish Nutrients in Your Soil
- Manuring (Biomanuring)
- Fertilizers
- Improved methods of agriculture
- Agricultural Assistance Programme
- Animal Husbandry (Livestock) > Poultry Farm Management
- Animal Husbandry (Livestock) > Pisciculture (Fish Farming)
- Animal Husbandry (Livestock) > Apiculture (Bee Farming)
Why Do We Fall ill
- Categories of Disease
- Acute and Chronic Diseases
- Causes of Disease
- Infectious Agents
- Manifestation of Diseases
- Modes of Transmission of Diseases
- Organ-specific and Tissue-specific Manifestations
- Principles of Prevention of Diseases
- Principles of Treatment of Diseases
Natural Resources
Estimated time: 10 minutes
CBSE: Class 12
Divisions of Algae and their Main Characteristics
| Classes | Common Name | Major Pigments | Stored Food | Cell Wall | Flagellar Number and Position of Insertions | Habitat |
|---|---|---|---|---|---|---|
| Chlorophyceae | Green algae | Chlorophyll a, b | Starch | Cellulose | 2–8, equal, apical | Fresh water, brackish water, salt water |
| Phaeophyceae | Brown algae | Chlorophyll a, c, carotenoids, xanthophylls | Mannitol, laminarin | Cellulose and algin | 2, unequal, lateral | Fresh water (rare), brackish water, salt water |
| Rhodophyceae | Red algae | Chlorophyll a, c, r-phycoerythrin | Floridean starch | Cellulose, pectin and polysulphate esters | Absent | Fresh water (some), brackish water, salt water (most) |
CBSE: Class 12
Classification of Sub-Division Algae
| Feature | Chlorophyceae (Green) | Phaeophyceae (Brown) | Rhodophyceae (Red) |
|---|---|---|---|
| Body form | Unicellular/colonial/filamentous | Simple to large complex forms | Mostly multicellular |
| Pigments | Chlorophyll a, b | Chlorophyll a, c, fucoxanthin | Chlorophyll a, d, phycoerythrin |
| Stored food | Starch | Mannitol, laminarin | Floridean starch |
| Cell wall | Cellulose | Cellulose + algin | Cellulose + pectin |
| Reproduction | Zoospores (2–8 equal flagella) | Zoospores (2 unequal flagella) | Non-motile spores/gametes |
| Habitat | Fresh, brackish, marine | Mostly marine | Mostly marine |
| Examples | Chlamydomonas, Spirogyra | Laminaria, Sargassum | Polysiphonia, Porphyra |
CBSE: Class 12
Key Points: Sub-division Algae
- Algae are simple, chlorophyll-containing, autotrophic organisms, mostly found in aquatic habitats.
- They have a thallus body without true roots, stems, and leaves.
- Algae show different forms, such as unicellular (Chlamydomonas), colonial (Volvox), and filamentous (Spirogyra).
- Reproduction occurs by vegetative, asexual, and sexual methods, including fragmentation and spore formation.
- Algae play an important role in CO₂ fixation and oxygen production, supporting aquatic ecosystems.
- They have economic importance, providing food, agar, algin, carrageenan, and protein-rich supplements like Spirulina.
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Related QuestionsVIEW ALL [29]
Match the following.
| Cyanophyceae | Green algae |
| Chlorophyceae | Blue-green algae |
| Phaeophyceae | Red algae |
| Rhodophyceae | Brown algae |
