Long Answer Type(a) Explain the different ways apomictic seeds can develop. Give an example of each.
(b) Mention one advantage of apomictic seeds to farmers.
(c) Draw a labelled mature stage of a dicotyledonous embryo.(a) State the objective of animal breeding.
(b) List the importance and limitations of inbreeding. How can the limitations be overcome ?
(c) Give an example of a new breed each of cattle and poultrya. ‘Breed’ is defined as the group of animal which are general appearance, feature, size and configuration etc.
When animals of same breed are crossed it is called as inbreeding and when the cross is between different breed then it is called outbreeding.
Objective of animal breeding:
1. For obtaining superior hybrid.
2. For increase production of animal product (milk).
3. For elimination of harmful recessive gene.
b.
Importance of inbreeding
1. Inbreeding increases homozygosity
2. Helps in accumulation of superior genes
3. Increases the productivity of inbred population.
Limitation and elimination of inbreeding
1. Inbreeding exposes harmful recessive genes and it can be removed by selection of genes.
2.Elimination of less desirable genes
3.Inbreeding depression, it can be over looked by mating of inferior animal with superior breed.
c. Example of a new breed each of cattle and poultry
1.Cattle breed- Jersey
2. Poultry breed- Leghorn
With advancements in genetics, molecular biology and tissue culture, new traits have been incorporated into crop plants. Explain the main steps in breeding a new genetic variety of a crop.
(a) Describe the various steps of Griffith’s experiment that led to the conclusion of the ‘Transforming Principle’.
(b) How did the chemical nature of the ‘Transforming Principle’ get established?
Describe how the lac operon operates, both in the presence and absence of an inducer in E.coli.
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