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Practice each question, then open the answer or worked solution.
Millions of chickens were killed in West Bengal, Assam, Orissa and Maharashtra recently. What was the reason?
To prevent the flu that has infected to the chicken from further spreading in other areas, the chickens in these states were killed.
Can gamma rays used for crop improvement programmes prove to be harmful to health? Discuss.
The rays then cause mutations in the crops and only the crop with desired and useful mutations are used for further growth. Also, humans are not in direct contact with the rays.
In animal husbandry, if two closely related animals are mated for a few generations, it results in loss of fertility and vigour. Why is this so?
Continued inbreeding causes inbreeding depression because, due to homozygosity, there is an accumulation of recessive genes in the animals and thus resulting in loss of fertility and vigour.
In the area of plant breeding, it is important not only to preserve the seeds of the variety being cultivated but also to preserve all its wild relatives. Explain with a suitable example.
The wild varieties of cultivated plants, although have very low yields, they have various resistant characteristics (genes) that can be introduced in other high-yielding plants.
Name a man-made cereal? Trace how it was developed and where it is used.
The man-made cereal is Triticale. This man-made cereal is a hybrid and was developed by crossing rye with wheat. This cereal is used as fodder. The fodder is the food for animals.
Fill in the blanks
I: Cellulases catalyse
II: Somatic hybridization
III: Pomato/Topato.
IV: Somatic hybrid
A few statements are given below, followed by a set of terms in a box. Pick the correct term and write it against the appropriate statement
a. Mating of closely related individuals within the same breed
b. Mating of animals of the same breed but having no common ancestors on either side for 4-6 generations
c. Mating of animals of two different species
d. Breeding of animals belonging to different breeds
(i) Crossbreeding, (ii) Inter-specific hybridization, (iii) Outbreeding, (iv) Outcrossing, (v) Inbreeding
a. Inbreeding
b. Outcrossing
c. Inter-specific breeding
d. Crossbreeding
What is meant by ‘hidden hunger’?
Hidden hunger means the deficiency of certain nutrients in the body in which no specific symptoms are seen.
Why are plants obtained by protoplast culture called somatic hybrids?
Plants obtained by protoplast culture are called somatic hybrids because these plants are formed by the fusion of protoplasts of two different plant varieties, each having desirable characteristics.
What is protoplast fusion?
The two plant varieties of plants with desirable characteristics are selected, and their cells are extracted, the cell walls of the cells are broken down by protein-digesting enzyme and the naked protoplast is fused under laboratory conditions. This is known as protoplast fusion.