Biotechnology in Agriculture and Health: Notes and PYQs

The correct answer is B, a bacterium. 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. Option A is wrong because viral genes are used for other purposes, such as the coat protein approach to virus resistance, not for Bt. Option C is wrong because fungi are used as biopesticides in their own right, as Trichoderma is against soil borne disease, but the cry gene is not fungal. Option D is wrong because algae such as Anabaena serve as biofertilisers in paddy fields rather than as a source of insecticidal genes. Remember the full name Bacillus thuringiensis behind the two letters Bt.

The correct answer is C, Bt cotton. 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. Option A is wrong because Bt brinjal, though developed and field tested, was placed under a moratorium in 2010 and has not been released. Option B is wrong because golden rice, engineered to make beta carotene in the grain, has never been approved for cultivation in India. Option D is wrong because genetically modified soybean is not approved for cultivation here, although imported soybean oil has been permitted at times. Statement based questions often claim that India grows several GM food crops, which is false; keep Bt cotton as the single approved crop and note the brinjal moratorium.

The correct answer is A, Kary Mullis. 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. Option B is wrong because Alec Jeffreys developed DNA fingerprinting, which identifies individuals from repeating sequences in their DNA. Option C is wrong because Herbert Boyer, with Stanley Cohen, constructed the first recombinant DNA molecule, which is a different landmark. Option D is wrong because Ian Wilmut led the team at the Roslin Institute that cloned Dolly the sheep in 1996 by somatic cell nuclear transfer. Examiners place all four names together, so link each to one technique and keep them apart.

The correct answer is B, vitamin A. 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. Option A is wrong because iron deficiency is addressed by biofortified varieties of pearl millet and wheat and by fortified foods, not by golden rice. Option C is wrong because iodine deficiency is tackled by iodised salt, a public health measure that needs no engineering of the crop. Option D is wrong because vitamin D is obtained largely from sunlight and from fortified milk. Golden rice is the standard example of biofortification by genetic engineering.

The correct answer is B, the Genetic Engineering Appraisal Committee. 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. Option A is wrong because the Review Committee on Genetic Manipulation, under the Department of Biotechnology, monitors research and small scale trials rather than commercial release. Option C is wrong because the National Biodiversity Authority, at Chennai, deals with access to biological resources and benefit sharing under the Act of 2002. Option D is wrong because ICAR conducts agricultural research and coordinates trials but grants no biosafety approval. Learn the pair as RCGM for research and GEAC for release.

The correct answer is B, plant breeding. Plant breeding is the deliberate improvement of crops by choosing parents with desirable characters, crossing them, selecting among the progeny and multiplying the best lines; the high yielding wheat and rice varieties of the Green Revolution came from it, and modern breeding is often combined with tissue culture and marker assisted selection. Option A is wrong because plant embryology studies the development of the embryo and seed, which is descriptive rather than an improvement programme. Option C is wrong because plant biochemistry studies the chemical reactions inside the plant, such as photosynthesis and secondary metabolites. Option D is wrong because plant anatomy studies internal structure and tissues under the microscope. Breeding works with genes already present in related plants, while genetic engineering can bring a gene from any organism.

The correct answer is A, totipotency. A single plant cell retains the capacity to divide and differentiate into every tissue and so to regenerate a whole plant, which is why an explant grown on a sterile nutrient medium can form callus and then complete plantlets. Option B is wrong because osmosis is the movement of water across a membrane and explains water uptake, not regeneration. Option C is wrong because transpiration is the loss of water vapour through stomata and has nothing to do with culture. Option D is wrong because photoperiodism is the response of flowering to day length. Tissue culture built on totipotency gives micropropagation for banana, sugarcane and orchids, virus free plants through meristem culture, and haploids through anther culture, all of which are asked as applications.

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.

The correct answer is B, human insulin produced in bacteria. The two polypeptide chains of the hormone are made in genetically engineered bacteria and then joined by disulphide bonds, giving insulin identical to the human hormone, which ended the dependence on insulin extracted from the pancreas of cattle and pigs and the allergy that sometimes followed. Option A is wrong because the hepatitis B vaccine is also a recombinant product, made from a viral surface protein grown in yeast, but it is a vaccine and not Humulin. Option C is wrong because growth hormone for therapy is also made by recombinant means today, not taken from sheep. Option D is wrong because antibiotics such as penicillin come from fungal fermentation, an older form of biotechnology. Insulin is the standard example of red biotechnology.

The correct answer is B, 1986. The Department of Biotechnology was created in 1986 under the Ministry of Science and Technology to give the subject a separate home, and it supports institutions, fellowships and national facilities; the Review Committee on Genetic Manipulation also works under it. Option A is wrong because 1974 is the year of the first Indian nuclear test and belongs to atomic energy, not biotechnology. Option C is wrong because 1999 is the year of the Geographical Indications Act and has no connection with this department. Option D is wrong because 2012 is the year the Biotechnology Industry Research Assistance Council was created to support industry and start ups, which candidates often confuse with the parent department. Note that the Environment (Protection) Act is also of 1986, and the biosafety rules under it came in 1989.