Rhizobium, found in the root nodules of leguminous plants, is used as a:
- A.Biopesticide
- B.Biofertiliser
- C.Herbicide
- D.Growth hormone
Correct answer
Explanation
The correct answer is B, a biofertiliser. Rhizobium lives in symbiosis in the root nodules of pulses and fixes atmospheric nitrogen into a form the plant can use, which enriches the soil and reduces the need for nitrogen fertiliser. Option A is wrong because biopesticides kill or control pests, and the examples are Bacillus thuringiensis against caterpillars, Trichoderma against soil borne fungi and the nuclear polyhedrosis virus against insect larvae. Option C is wrong because a herbicide kills weeds, and Rhizobium has no such action. Option D is wrong because growth hormones of plants are auxins, gibberellins and cytokinins, which are chemical substances and not bacteria. The other biofertilisers to remember are Azotobacter and Azospirillum, free living nitrogen fixers, Anabaena in Azolla for paddy and mycorrhizal fungi for phosphorus uptake.
Read the full article: Biotechnology in Agriculture and Health: Notes and PYQs
Practice Questions
View allThe Bt gene used in Bt cotton is obtained from which organism?
- A.A virus
- B.A bacterium
- C.A fungus
- D.An alga
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The cry genes of Bt cotton come from Bacillus thuringiensis, a soil bacterium that forms crystal protein during sporulation; the protein is inactive as eaten but becomes a toxin in the alkaline gut of the bollworm, which is why the plant resists the pest.
Read the full explanation →Which genetically modified crop is approved for commercial cultivation in India?
- A.Bt brinjal
- B.Golden rice
- C.Bt cotton
- D.GM soybean
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Approved in 2002, it is the only genetically modified crop cleared for commercial cultivation by Indian farmers, and it is grown for fibre rather than as food.
Read the full explanation →The polymerase chain reaction, used to multiply a chosen segment of DNA, was invented by:
- A.Kary Mullis
- B.Alec Jeffreys
- C.Herbert Boyer
- D.Ian Wilmut
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He devised the polymerase chain reaction, which copies a selected stretch of DNA millions of times through repeated cycles of heating and cooling, using the heat resistant Taq polymerase, and he received the Nobel Prize in Chemistry for it.
Read the full explanation →Golden rice was developed to address the deficiency of which nutrient?
- A.Iron
- B.Vitamin A
- C.Iodine
- D.Vitamin D
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Golden rice was engineered to make beta carotene, the precursor from which the body forms vitamin A, in the edible part of the grain, and the pigment gives the rice its golden colour; the aim was to reduce night blindness among populations living mainly on rice.
Read the full explanation →Which body is the apex authority for approving the environmental release of genetically engineered organisms in India?
- A.Review Committee on Genetic Manipulation
- B.Genetic Engineering Appraisal Committee
- C.National Biodiversity Authority
- D.Indian Council of Agricultural Research
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Working under the Ministry of Environment, Forest and Climate Change, it is the apex committee under the rules of 1989 framed under the Environment (Protection) Act, 1986, and no genetically engineered organism may be released into the environment or used on a large scale without its clearance.
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