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What does the Principles of Inheritance and Variation revision sheet cover?

Mendel's three laws, Law of Dominance, Law of Segregation, Law of Independent Assortment, Key terms, Monohybrid cross: Tt selfed, Genotype vs Phenotype, Genotype, Phenotype, Predicting a dihybrid F2 ratio, Back cross vs Test cross, Back cross.

Is this for Class 12 CBSE Biology?

It is written from the NCERT syllabus, so it serves CBSE and any board that follows NCERT for Biology.

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Principles of Inheritance and Variation — Class 12 CBSE Biology revision notes

A 6-page visual revision sheet for Principles of Inheritance and Variation, written for Class 12 CBSE Biology. Formulas, diagrams and the traps that cost marks, laid out to be read the night before rather than the term before. Free, and it opens inside CapCompass.

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Principles of Inheritance and Variation in one look

one gene, two alleles, and a ratio that gives the mechanism away

Mendel's three laws

Law of Dominance: in a heterozygote, one allele expresses fully and masks the other, which stays hidden but unaltered
Law of Segregation: the two alleles of a gene separate during gamete formation, so each gamete carries only one of them, never both
Law of Independent Assortment: alleles of different genes assort into gametes independently of each other, as long as the genes sit on different chromosomes

Key terms

allele: an alternative form of a gene, occupying the same locus on homologous chromosomes
genotype: the allele combination an organism carries; phenotype: the trait that combination actually expresses
homozygous: both alleles of a gene identical, TT or tt; heterozygous: the two alleles differ, Tt
a true-breeding line, self-fertilized over several generations, shows no variation in the trait being followed

Genotype vs Phenotype

Genotype

the actual allele combination carried, e.g. Tt
not directly visible; worked out through breeding experiments like a test cross

Phenotype

the observable, expressed trait, e.g. tall
what a Punnett square is ultimately trying to predict from the genotype behind it

Page 1 of 6. The full sheet, all 6 pages, opens free in the app.

What this Principles of Inheritance and Variation sheet covers

Mendel's three laws
Law of Dominance
Law of Segregation
Law of Independent Assortment
Key terms
Monohybrid cross: Tt selfed
Genotype vs Phenotype
Genotype
Phenotype
Predicting a dihybrid F2 ratio
Back cross vs Test cross
Back cross
Test cross
Interactions between alleles of one gene
Incomplete dominance vs Co-dominance
Incomplete dominance
Co-dominance
Pleiotropy and polygenic inheritance
Chromosomal theory of inheritance
Linkage and crossing over
Sex determination
Sex-linked inheritance
One sibship: a carrier mother, a normal father
Mutation
One segment goes wrong. Which way?
Genetic disorders
Traps that cost marks
Tricks that save time

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