F 1 progeny of pea plant bearing violet flowers and snapdragon plant bearing red flowers were selfed to produce their respective F 2 progeny. Compare the phenotype, genotype and pattern of inheritance of their respective F 2 progeny.

The snapdragon flower shows incomplete dominance. If a plant with red coloured flowers (RR) is crossed with a plant with white coloured flower (rr), the F 1 progeny shows (Rr) the plant with pink coloured flowers. Hence, in the condition in which the selfing of the plant bearing red flower, they have RR genotype. Phenotype: All plants are bearing red coloured flowers. Phenotypic ratio: 100% Genotype: RR Genotypic ratio: RR (100%) In pea plants, the violet flower is the dominant trait. Hence, the genotype of violet flower may be homozygous (WW) or heterozygous (Ww). The pattern of inheritance is complete dominance. If the plant with violet flower is homozygous, Phenotypic ratio: All are violet (100%) Genotypic ratio: WW(100%) If the plant with violet flower is heterozygous, Phenotypic ratio: 3:1 (3 violet flowers :1 white flower) Genotypic ratio: 1:2:1 (WW:Ww:ww)

F 1 progeny of pea plant bearing violet flowers and snapdragon plant bearing red flowers were selfed to produce their respective F 2 progeny. Compare the phenotype, genotype and pattern of inheritance of their respective F 2 progeny.

The snapdragon flower shows incomplete dominance. If a plant with red coloured flowers (RR) is crossed with a plant with white coloured flower (rr), the F 1 progeny shows (Rr) the plant with pink coloured flowers. Hence, in the condition in which the selfing of the plant bearing red flower, they have RR genotype. Phenotype: All plants are bearing red coloured flowers. Phenotypic ratio: 100% Genotype: RR Genotypic ratio: RR (100%) In pea plants, the violet flower is the dominant trait. Hence, the genotype of violet flower may be homozygous (WW) or heterozygous (Ww). The pattern of inheritance is complete dominance. If the plant with violet flower is homozygous, Phenotypic ratio: All are violet (100%) Genotypic ratio: WW(100%) If the plant with violet flower is heterozygous, Phenotypic ratio: 3:1 (3 violet flowers :1 white flower) Genotypic ratio: 1:2:1 (WW:Ww:ww)

Generally, it is observed that human males suffer from haemophilia more than human females, who rarely suffer from it. Explain giving reasons.

Haemophilia is a recessive X-linked genetic type disorder. Human females are homogametic and have two X chromosomes (XX) while males are heterogametic and have XY chromosomes. Haemophilia is more common among males than females because males only inherit one X-chromosome. The male offspring inherit X-chromosome from their mother and Y-chromosome from the father. Since males only have one X-chromosome thus there are more chances of their being affected. For females to get affected by this disease they need two X chromosomes that contain the gene for haemophilia. So their chances of being haemophilic are less, comparatively.

E M B I B E

EMBIBE CHAPTER WISE PREVIOUS YEAR PAPERS FOR BIOLOGY>Chapter 5 - Principles of Inheritance and Variation>CBSE-2020>Q 10

HARD

12th CBSE

IMPORTANT

Earn 100

F₁ progeny of pea plant bearing violet flowers and snapdragon plant bearing red flowers were selfed to produce their respective F₂ progeny. Compare the phenotype, genotype and pattern of inheritance of their respective F₂ progeny.

Important Questions on Principles of Inheritance and Variation

HARD

12th CBSE

IMPORTANT

EMBIBE CHAPTER WISE PREVIOUS YEAR PAPERS FOR BIOLOGY>Chapter 5 - Principles of Inheritance and Variation>CBSE-2018>Q 1

Explain the mechanism of 'sex determination' in birds. How does it differ from that of human beings?

HARD

12th CBSE

IMPORTANT

EMBIBE CHAPTER WISE PREVIOUS YEAR PAPERS FOR BIOLOGY>Chapter 5 - Principles of Inheritance and Variation>CBSE-2018>Q 2

Write the scientific name of the organism Thomas Hunt Morgan and his colleagues worked with for their experiments. Explain the correlation between linkage and recombination with respect to genes as studied by them.

HARD

12th CBSE

IMPORTANT

EMBIBE CHAPTER WISE PREVIOUS YEAR PAPERS FOR BIOLOGY>Chapter 5 - Principles of Inheritance and Variation>CBSE-2018>Q 3

How did Sturtevant explain gene mapping while working with Morgan?

EASY

12th CBSE

IMPORTANT

EMBIBE CHAPTER WISE PREVIOUS YEAR PAPERS FOR BIOLOGY>Chapter 5 - Principles of Inheritance and Variation>CBSE-2019>Q 4

Name a human genetic disorder due to the following :
An additional X-chromosome in a male

EASY

12th CBSE

IMPORTANT

EMBIBE CHAPTER WISE PREVIOUS YEAR PAPERS FOR BIOLOGY>Chapter 5 - Principles of Inheritance and Variation>CBSE-2019>Q 5

Name a human genetic disorder due to the following :
Deletion of one X-chromosome in a female

EASY

12th CBSE

IMPORTANT

EMBIBE CHAPTER WISE PREVIOUS YEAR PAPERS FOR BIOLOGY>Chapter 5 - Principles of Inheritance and Variation>CBSE-2019>Q 6

State what does aneuploidy lead to.

EASY

12th CBSE

IMPORTANT

EMBIBE CHAPTER WISE PREVIOUS YEAR PAPERS FOR BIOLOGY>Chapter 5 - Principles of Inheritance and Variation>CBSE-2019>Q 7

How does mutation occur?

HARD

12th CBSE

IMPORTANT

EMBIBE CHAPTER WISE PREVIOUS YEAR PAPERS FOR BIOLOGY>Chapter 5 - Principles of Inheritance and Variation>CBSE-2019>Q 8

Mendel crossed a homozygous pea plant having yellow and round seeds with another pea plant bearing green and wrinkled seeds. He found that in some of the F₂ population, new combinations of the parental characters were observed. How will you explain the appearance of a new combination of the parental characters in F₂ offspring? Support your answer with the help of a Punnett square.