Chapter 3 of 15
Revision Notes
Inheritance and Variation — Revision Notes
Maharashtra Board · Class 12 · Biology
Inheritance and Variation revision notes for Maharashtra Board Class 12 Biology: 4 topics in quick points. Includes Mendel's Laws and Basic Genetics.
45 questions25 flashcards5 concepts
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Key Topics to Revise
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1. Mendel's Laws and Basic Genetics
- Gregor Mendel (1822-1884) established the fundamental principles of heredity using garden pea (Pisum sativum)
- Mendel chose pea plants because: contrasting visible characters, self-pollinating, short life cycle, large number of offspring
- Seven pairs of contrasting traits studied: seed shape, seed color, pod shape, pod color, flower color, flower position, plant height
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2. Mendel's Three Laws
- Law of Dominance: In heterozygous condition, only dominant allele expresses; recessive allele remains hidden
- Law of Segregation (Purity of Gametes): Allele pairs separate during gamete formation; each gamete carries only one allele
- Law of Independent Assortment: Different trait pairs assort independently during gamete formation
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3. Deviations from Mendelian Inheritance
- Incomplete Dominance: Neither allele completely dominates; F1 shows intermediate phenotype
- Co-dominance: Both alleles express simultaneously in heterozygous condition
- Multiple Alleles: More than two alternative forms of a gene exist in population
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4. Chromosomal Theory of Inheritance
- Proposed by Sutton and Boveri (1903) - chromosomes are carriers of genetic material
- Genes are located on chromosomes at specific positions called loci
- Homologous chromosomes carry alleles for same traits at corresponding loci
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Full NotesKey Concepts
Three fundamental lawsEssential terms includeMonohybrid cross involves one trait (eNonProposed by Sutton and Boveri
Frequently Asked Questions
What are the important topics in Inheritance and Variation for Maharashtra Board Class 12 Biology?
Key topics in Inheritance and Variation include Mendel's Laws and Basic Genetics, Mendel's Three Laws, Deviations from Mendelian Inheritance, Chromosomal Theory of Inheritance. Study these first, then practise questions on each for the Maharashtra Board Class 12 board exam.
How should I revise Inheritance and Variation for the Maharashtra Board Class 12 board exam?
Learn the core ideas first, then work through the 45 practice questions on Inheritance and Variation. Revise definitions regularly and use flashcards for quick recall before the exam.
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Content is aligned to the official syllabus. Refer to the board website for the latest curriculum.
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