Biology Quick Revision for Class 11 & 12
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Biology Quick Revision for Class 11 & 12 – Definitions, Cycles, Diagrams, Key Facts
Biology for Class 11 and 12 is about understanding concepts, recalling facts, drawing diagrams, and applying processes. Hodu Academy presents a chapter-wise collection of important definitions, summary tables, key cycles, and diagrams—perfect for board exams, NEET, Olympiads, and last-minute revision.
Use these notes for NCERT, CBSE, ISC, and State Boards—and for competitive exams like NEET.
Bookmark this page for exam-time revision and memory hacks!
Table of Content
- Class 11 Biology Quick Revision List
- Class 11 Chapter-wise Key Facts
- Class 12 Biology Quick Revision List
- Class 12 Chapter-wise Key Facts
- Important Cycles & Processes
- Summary Tables & Classifications
- Must-Draw Diagrams
- Key Definitions & Terms
- How to Ace Biology Theory & Memory Tips
- FAQs on Biology Revision
Class 11 Biology Quick Revision List
| Chapter Name | Must-Know Points |
|---|---|
| The Living World | Taxonomy hierarchy, Binomial nomenclature, Characteristics of living things |
| Biological Classification | Five Kingdom System, Kingdom features, Viruses, Lichens |
| Plant Kingdom | Algae, Bryophytes, Pteridophytes, Gymnosperms, Angiosperms, Alternation of generations |
| Animal Kingdom | Non-chordates vs Chordates, Phylum characteristics, Symmetry, Coelom types |
| Morphology of Flowering Plants | Root, Stem, Leaf, Inflorescence, Flower, Fruit, Seed structure |
| Anatomy of Flowering Plants | Tissues (simple, complex), Anatomy of dicot/monocot root, stem, leaf |
| Cell: Structure and Function | Cell theory, Prokaryote vs Eukaryote, Organelles, Cell division |
| Biomolecules | Proteins, Carbohydrates, Lipids, Nucleic acids, Enzymes |
| Plant Physiology (Transport, Photosynthesis, Respiration, Growth) | Water transport, Transpiration, Photosynthesis steps, Respiration, Growth hormones |
| Human Physiology (Digestion, Breathing, Circulation, Excretion, Movement, Neural & Chemical Control) | Human body systems, Digestive enzymes, Heart structure, Nephron, Muscles, Hormones |
Class 11 Biology: Chapter-wise Key Facts
Note: These are most exam-relevant summary points, diagrams & keywords.
The Living World:
- Taxonomic Hierarchy: Kingdom → Phylum → Class → Order → Family → Genus → Species
- Binomial Nomenclature: Genus + species (e.g., Homo sapiens)
- ICBN/ICZN codes for plants/animals
Biological Classification:
- Five Kingdoms: Monera, Protista, Fungi, Plantae, Animalia
- Kingdom Monera: Prokaryotes (Bacteria, Cyanobacteria)
- Virus = living + non-living properties
Plant Kingdom:
- Alternation of Generations: Haploid (gametophyte) → Diploid (sporophyte)
- Algae → Bryophytes → Pteridophytes → Gymnosperms → Angiosperms
- Example: Funaria (Bryophyte), Fern (Pteridophyte)
Animal Kingdom:
- Levels of Organization: Cellular → Tissue → Organ → Organ system
- Symmetry: Asymmetrical, Radial, Bilateral
- Coelom types: Acoelomate, Pseudocoelomate, Coelomate
Morphology & Anatomy of Flowering Plants:
- Dicot vs Monocot differences
- Tissue types: Parenchyma, Collenchyma, Sclerenchyma
- Transverse section of root/stem/leaf
Cell: Structure & Function:
- Cell organelles (structure & function): Nucleus, Mitochondria, ER, Golgi
- Cell cycle, Mitosis vs Meiosis differences
Biomolecules:
- Monomer vs Polymer: Glucose (carb), Amino acid (protein), Nucleotide (DNA/RNA)
- Enzyme action: Substrate, Active site, Inhibition
Plant Physiology:
- Photosynthesis: Light & Dark reactions, Chlorophyll
- Transport: Xylem (water), Phloem (food), Transpiration pull
- Plant hormones: Auxin, Gibberellin, Cytokinin, Abscisic acid
Human Physiology:
- Digestive system: Enzymes, Peristalsis, Absorption
- Circulatory system: Heart structure, Double circulation
- Excretory system: Nephron structure, Urine formation
- Neural & Chemical coordination: Brain parts, Endocrine glands
Class 12 Biology Quick Revision List
| Chapter Name | Must-Know Points |
|---|---|
| Reproduction in Organisms | Asexual vs Sexual, Reproductive cycles, Life span, Examples |
| Genetics & Evolution | Mendel’s Laws, Chromosome theory, DNA structure, Evolutionary evidence |
| Biotechnology | DNA cloning, PCR, Restriction enzymes, Applications in health & agriculture |
| Human Health & Diseases | Immunity types, Pathogens, Vaccines, AIDS, Cancer |
| Ecology & Environment | Ecosystem, Food chain, Biogeochemical cycles, Pollution |
| Microbes in Human Welfare | Antibiotics, Fermentation, Sewage treatment, Biocontrol |
| Strategies for Enhancement in Food Production | Plant/animal breeding, Tissue culture, GM crops |
| Evolution | Darwin’s theory, Hardy-Weinberg law, Speciation |
| Organisms and Populations | Population interactions, Adaptations, Ecological succession |
Class 12 Biology: Chapter-wise Key Facts
Reproduction in Organisms:
- Asexual reproduction: Binary fission, budding, spore formation
- Sexual reproduction: Gametogenesis, Fertilization, Zygote formation
Genetics & Evolution:
- Mendel’s Laws: Dominance, Segregation, Independent Assortment
- Monohybrid vs Dihybrid cross, Phenotypic ratios
- DNA/RNA structure, Central Dogma
- Hardy-Weinberg equilibrium: p² + 2pq + q² = 1
Biotechnology:
- Restriction Enzymes: Cut DNA at specific sequences
- DNA Cloning, Vectors (plasmids), PCR steps
Human Health & Diseases:
- Types of Immunity: Innate, Acquired
- Vaccination, Allergy, Autoimmune disease
Ecology & Environment:
- Biogeochemical cycles: Water, Carbon, Nitrogen, Phosphorus
- Food web, Food pyramid, Energy flow
- Types of Pollution: Air, Water, Soil
Microbes in Human Welfare:
- Antibiotics, Vaccines, Fermentation
- Sewage treatment, Biogas production
Strategies for Enhancement in Food Production:
- Plant/animal breeding, Artificial selection
- Tissue culture (micropropagation)
Evolution:
- Darwin’s theory of Natural Selection
- Speciation, Adaptive radiation
Organisms and Populations:
- Population growth models: Exponential, Logistic
- Population interactions: Mutualism, Parasitism, Competition
Important Biological Cycles & Processes
- Photosynthesis: Light Reaction (in thylakoids) → ATP, NADPH; Dark Reaction (Calvin Cycle in stroma) → Glucose
- Respiration: Glycolysis → Krebs cycle → Electron transport chain (in mitochondria)
- DNA Replication: Semi-conservative, 5' to 3' direction, Enzymes: DNA polymerase, helicase, ligase
- Protein Synthesis: Transcription (DNA→mRNA) → Translation (mRNA→Protein)
- Menstrual Cycle: Follicular phase → Ovulation → Luteal phase → Menstruation
- Water Cycle, Nitrogen Cycle, Carbon Cycle – memorize steps and diagrams for each.
Summary Tables & Classifications
| Term/Group | Examples/Classification |
|---|---|
| Taxonomic Hierarchy | Kingdom, Phylum, Class, Order, Family, Genus, Species |
| Plant Hormones | Auxins, Gibberellins, Cytokinins, Abscisic Acid, Ethylene |
| Types of Immunity | Innate, Acquired, Active, Passive |
| Types of Enzymes | Oxidoreductases, Transferases, Hydrolases, Lyases, Isomerases, Ligases |
| Types of Chromosomes | Metacentric, Submetacentric, Acrocentric, Telocentric |
| Levels of Organization | Cell → Tissue → Organ → Organ System → Organism |
| Types of Neurons | Sensory, Motor, Interneurons |
| Mendel’s Ratios | Monohybrid: 3:1; Dihybrid: 9:3:3:1 |
Must-Draw Diagrams for Exams
- Transverse section of dicot and monocot stem/leaf/root
- Structure of typical animal/plant cell (label all organelles!)
- Mitochondria and Chloroplast (ultrastructure)
- Human Heart, Nephron, Brain (with labelled parts)
- Flower structure (L.S.), Germination of pollen on stigma
- DNA double helix, mRNA, tRNA
- Immunity (antibody, antigen structure), Food chain pyramid
Key Biology Definitions & Terms
- Taxonomy: Science of naming, classifying organisms
- Allele: Alternate form of a gene
- Enzyme: Biological catalyst speeding up reactions
- Osmosis: Movement of water across semipermeable membrane
- Photosynthesis: Process of making food using sunlight, CO₂, H₂O
- Mutation: Change in DNA sequence
- Immunity: Ability to resist infection/disease
- Symbiosis: Two organisms living together for mutual benefit
- Genotype/Phenotype: Genetic constitution/physical appearance
- Antibody: Protein produced in response to antigen
How to Ace Biology Theory & Memory Tips
- Make summary charts of cycles (photosynthesis, respiration, nitrogen cycle, etc.)
- Practice drawing diagrams, label every part, mark differences (dicot/monocot etc.)
- Use mnemonics for lists (Kingdoms, Enzyme types, Plant hormones)
- Focus on tables, differences, one-word answers for MCQs
- Revise key terms—write flashcards for difficult words/definitions
- Practice NCERT line diagrams, short notes, previous year NEET/Board questions
Tip: Before exams, revise this page and redraw 5-6 key diagrams every day!
Frequently Asked Questions (FAQs) – Biology Revision
- Q1. Are there formulas in Biology?
Biology has fewer formulas than Physics or Maths, but many cycles, definitions, and diagrams to memorize. Some topics (genetics, population, ecology) do use simple equations. - Q2. What are the must-revise Biology topics for NEET/Boards?
Cell structure, Human physiology, Plant physiology, Genetics, Ecology, Biotechnology, Diagrams and cycles! - Q3. How do I improve memory for Biology?
Make mind maps, use mnemonics, repeat diagrams, teach someone else, and revise from NCERT regularly. - Q4. Which diagrams are most important?
Transverse sections (root, stem, leaf), heart, nephron, brain, flower, DNA, food chain pyramid, cell organelles.
Bookmark Hodu Academy Biology Resources for updates, mind maps, PDF downloads, and expert video lessons for every chapter!
Last modified: Saturday, 5 July 2025, 1:36 PM