NCERT Class 11 Biotechnology Sixth Chapter Basic Principles of Inheritance Solution
NCERT Class 11 Biotechnology Chapter 6 Solution: Dear students Here in this post we are posted Sixth Chapter Basic Principles of Inheritance full exercise questions & answer by our arts teacher. This Solution is helpful for CBSE English medium students. Download this 6th Chapter Biotechnology solution & prepare your homework.
Q1. Differentiate between:-
- Genotype and phenotype-
Genotype | Phenotype |
Genotype is the probability of all possible genetic combinations. | Phenotype is the probability of all morphological characters. |
This is the progenies which are identified genetically | This is the progenies which are identified by physical appearance. |
The ratio obtained by genotypes is called as genotypic ratio. | The ratio obtained by phenotypes is called as phenotypic ratio. |
- Heterozygous and homozygous progeny-
Heterozygous progeny | Homozygous progeny |
Heterozygous progeny is in which the progeny contain two differentalleles. | Homozygous progeny is which the progeny contain one allele. |
- Monohybrid and dihybrid cross-
Monohybrid cross | Dihybrid cross |
The cross made between parents with one pair of contrasting character is called as monohybrid cross. | The cross of two pairs of contrasting characters is called as dihybrid cross. |
The phenotypic ratio is 3:1 and genotypic ratio is 1:2:1 of monohybrid cross. | The phenotypic ratio of dihybrid cross is 9:3:3:1. |
- Gene and allele
Gene | Allele |
Gene is a DNA segment by which characters are controlled. | The genes which exists in two alternate form are called as alleles. |
Genes located on same chromosome are known as linked genes. | Alleles which are present in individual with two similar allele for a trait is homozygous allele. |
All genes which are located on single chromosome are called as linkage group. | Alleles which are different for a trait is heterozygous allele. |
- Incomplete dominance and co dominance-
Incomplete dominance | Co-dominance |
The condition in which alleles are expressed itself partially is called as incomplete dominance. | The condition in which alleles of both parents are equally expressed is called as co-dominance. |
This is observed in the colour of bearing flower. | This is observed in coat colour of horse, cow. |
Q2. Mention the genotypic ratio of progeny when there is cross between:
F1 progeny with pure dominant parent-
Phenotypic ratio- 3:1, Genotypic ratio- 1:2:1
F1 progeny with pure recessive parent-
Phenotypic ratio- 9:3:3:1, Genotypic ratio- 1:2:1:2:4:2:1:2:1
F1 progeny with F1 progeny-
Phenotypic ratio- 3:1, Genotypic ratio- 1:2:1
Q3. Explain test cross through diagrammatic representation.
Ans- Test cross is the cross between the same progeny of F2 generation. The cross between tall plant and dwarf plant is test cross. Mendel crossed the tall plant of F2
generation with dwarf plant and called it as test cross.
A test cross is a cross which helps to determine whether a dominant phenotype is heterozygous or homozygous of allele.
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Q4. Explain the following using monohybrid cross.
1.Law of dominance:-
Law of dominance states that in the cross the allele has contrasting characters in which one is dominant and other is recessive. The cross between pure dwarf and pure tall plant determines the ratio of law of dominance.By crossing pure tall and pure dwarf plant the ratio obtained is :
Phenotypic ratio- 3:1 ,Genotypic ratio- 1:2:1
2.Law of segregation:-
According to this law of segregation the alleles of traits segregate in the process of inheritance. This cross is also explained by the cross between tall plant and dwarf plant. Other example of law of segregation is observed in colour of flower. The cross between red flower and white flowers. By crossing red flower and white flower the ratio obtained is:
Phenotypic ratio- 3:1, genotypic ratio- 1:2:1
3.Law of independent assortment:-
According to this law of independent assortment of alleles, the factors or genes which are a specific controlling trait is inherited independently to each other.This is explained by seed shape, the cross between round seed and wrinkled seed. By crossing the round seed and wrinkled seed the ratio obtained is: Phenotypic ratio- 3:1, genotypic ratio- 1:2:1
Q7. Make a close observation in nature. Do you think that the phenomenon of linkage is absolute?
Ans- Linkage is the phenomenon in which the inheritance of genes retain their parental combination even in the presence of their offspring. This is absolute we can observe this even in nature. Some things which are done in nature are close to linkage.
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