2000 General Studies, all questions
UPSC Prelims 2000 · General Studies
Question 121: Science and Technology
Insect resistant cotton plants have been genetically engineered by inserting a gene from a/an
avirus
bbacterium
cinsect
dplant
AnswerThe answer is (b).
Insect-resistant cotton, Bt cotton, carries a gene from the soil bacterium Bacillus thuringiensis. The gene makes a protein toxin that kills the bollworm caterpillars which eat the plant, so less insecticide is needed. Viral, insect or plant genes are not the source of this resistance. India approved Bt cotton for commercial growing in 2002.
Why each option is right or wrong
- (a) Viral genes are used to make plants resistant to viruses, not to insects.
- (b) Right: Bt cotton uses a gene from a bacterium.
- (c) An insect gene is not the source of the resistance in Bt cotton.
- (d) Plant genes are used in some experimental crops, but Bt cotton uses a bacterial gene.
Explanation: written by UPSC Grade, not by UPSC.
Source: UPSC, Civil Services (Preliminary) Examination 2000, General Studies. UPSC's own paper isn't online; the words are from a published compilation. The paper on upsc.gov.in.