CBSE Class 12 Biology Principles of Inheritance and Variation Key Points

This Class 12 Biology key points sheet for CBSE Chapter 5 Principles of Inheritance and Variation (Unit VII, Genetics and Evolution) defines the basic genetic terms: heredity, alleles, phenotype, genotype, homozygote, heterozygote, dominant and recessive characters, and monohybrid and dihybrid crosses. It also lists the full forms of two amino acid abbreviations.

UNIT-VII - GENETICS AND EVOLUTION
CHAPTER - 5 : PRINCIPLES OF INHERITANCE AND VARIATION (KEY POINTS)

KEY TERMS AND EXPLANATIONS

1. Heredity: It can be defined as the transmission of characters from one generation to successive generations of living organisms.
2. Alleles: The various forms of a gene are called alleles.
3. Phenotype: The external / observable characteristics of an organism constitute its phenotype.
4. Genotype: The genetic constitution of an organism is its genotype.
5. Homozygote: It is an individual organism in which the members of a pair of alleles for a character are identical.
6. Heterozygote: It is an individual organism in which the members of a pair of alleles of a character are different.
7. Dominant: The form of the character which is expressed in the F1 hybrid is called dominant character.
8. Recessive: The form of the character which is suppressed in the presence of the dominant character in a hybrid is called recessive character.
9. Monohybrid cross: It is a cross between individuals of the same species, in which the inheritance of contrasting pairs of a single trait is considered.
10. Dihybrid cross: It is a cross between two individuals of the same species, in which the inheritance of contrasting pairs of two traits is considered.

AMINO ACID ABBREVIATIONS

11. Glu - glutamic acid
12. Val - valine