Class 12 Biology Chapter 5 – Principles of Inheritance and Variation is a core NCERT chapter that appears frequently in CBSE Board exams and competitive tests like NEET. These handwritten notes PDF (2025-26) provide clear, exam-oriented summaries, labelled diagrams and important questions — perfect for quick revision and concept clarity.
📘 Chapter Snapshot
- Chapter: Principles of Inheritance and Variation
- Class: 12 Biology
- Session: 2025-26
- Format: Handwritten Notes PDF (chapter-wise)
- Best for: CBSE Boards, NEET, quick revision & classroom review
📖 Topics Covered (Syllabus Index)
- Mendel’s Laws: Law of Segregation and Law of Independent Assortment
- Monohybrid and Dihybrid crosses – Punnett squares & examples
- Chromosomal theory of inheritance
- Sex determination in humans (XX/XY), mechanism and exceptions
- Linked genes and recombination – crossing over
- Mutation: types, causes and significance
- Chromosomal disorders – Down’s syndrome, Klinefelter’s, Turner’s syndrome
- Pedigree analysis and applications
- Human Genome Project – brief overview and implications
- Important diagrams, flowcharts and typical board questions
⭐ Why these Handwritten Notes help
- Concise explanation of Mendelian crosses with solved examples.
- Clear labelled diagrams for chromosomal behaviour and pedigrees.
- Quick summary of mutation types and clinical significance.
- Board & NEET oriented: highlights frequently asked points and difficulty-level questions.
- Perfect for last-minute revision — compact, readable and well-structured.
📥 Download Handwritten Notes PDF
📥 Download Chapter 5 – Principles of Inheritance & Variation (Handwritten PDF)
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✅ Quick Revision Tips (2–3 mins)
- Memorise Mendel’s terminology (dominant, recessive, phenotype, genotype) and practice Punnett squares.
- Learn key chromosomal disorders with their chromosomal changes and symptoms.
- Understand difference between mutation and recombination and their roles in variation.
- Practice 2–3 pedigree problems — they often appear in board/competitive exams.
🔬 Conclusion
These handwritten chapter-wise notes for Principles of Inheritance and Variation are crafted to make revision fast and reliable. Download the PDF, revise the flowcharts and practice a few crosses — and you’ll be exam-ready.
