Assertion & Reason Test: Biotechnology & Its Applications - Grade 12 MCQ

Both assertion (A) and reason (R) are true and reason (R) is the correct explanation of assertion (A).

The Ti plasmid (tumour-inducing plasmid) of Agrobacterium tumefaciens is used as a cloning vector. Ti plasmid integrates a segment of its DNA, termed T-DNA into the chromosomal DNA of its host plant cells. This is the mechanism that allows for the transfer of genetic information from the plasmid to the plant cell, which is used to genetically modify the plant. The T-DNA region contains genes that are responsible for the formation of a tumour and also contains genes that can be used for genetic engineering. Therefore, the reason (R) explains the assertion (A) correctly.

Assertion (A) is true, but reason (R) is wrong as Bt toxin is produced by a bacterium called Bacillus thuringiensis.

The Green Revolution was an endeavour initiated by Norman Borlaug in the 1960s. He is known as the 'Father of Green Revolution' in world. It led to him winning the Nobel Peace Prize in 1970 for his work in developing High Yielding Varieties (HYVs) of wheat. In India, the Green Revolution was mainly led by M.S. Swaminathan. The Green Revolution resulted in a great increase in production of food grains (especially wheat and rice) due to the introduction into developing countries of new, high-yielding variety seeds, beginning in the mid-20th century. Its early dramatic successes were in Mexico and the Indian subcontinent. The Green Revolution, spreading over the period from 1967-68 to 1977-78, changed India’s status from a food-deficient country to one of the world's leading agricultural nations.

- Correct Answer: A: Both assertion (A) and reason (R) are true and reason (R) is the correct explanation of assertion (A).
- Explanation:
- Genetically modified crops are engineered to withstand abiotic stresses like cold and drought.
- GMOs have their genetic makeup altered through manipulation, which confers traits for stress tolerance.
- Therefore, genetic modification enables crops to exhibit enhanced resilience to adverse environmental conditions by introducing specific genes for stress tolerance. 

Low concentration of a bacteria or virus, even at a time when the symptoms of the disease are not visible, can be detected by amplification of their nucleic acid by PCR methods.