Biotechnology and its Applications
16 solved NEET Biology previous year questions on Biotechnology and its Applications, each with the correct answer and a full explanation.
Q1
The process of RNA interference (RNAi) has been used in the development of plants resistant to
✓ Correct answer: a) nematodes
ExplanationRNA interference (RNAi) has been employed to develop plants resistant to nematodes, parasitic worms causing plant diseases.Through RNAi, specific RNA molecules are introduced, silencing nematode genes crucial for their survival, providing an effective and environmentally friendly method for controlling nematode infestations in crops.
Q2
The laws and rules to prevent unauthorised exploitation of bio-resources are termed as:
✓ Correct answer: d) biopatenting.
ExplanationThe laws and rules to prevent unauthorized exploitation of bio- resources are termed as biopatenting.Biopiracy is the term used to refer to the use of bio-resources by multinational companies and other organisations without proper authorisation from the countries and people concerned without compensatory payment. [New NCERT Class 12th Page No. 184, 185]
Q3
Given below are two statements. Statement I : Bt toxins are insect group specific and coded by a gene cry IAc. Statement II : Bt toxin exists as inactive protoxin in B. thuringiensis. However, after ingestion by the insect the inactive protoxin gets converted into active form due to acidic pH of the insect gut. In the light of the above statements, choose the most appropriate answer from the options given below. [NEET 2024]
✓ Correct answer: d) Statement I is true but Statement II is false.
ExplanationStatement I is true because Bt toxins are insect group-specific and coded by the cry gene, such as cryIAc.Statement II is false because the inactive protoxin is converted to an active toxin due to the alkaline pH (not acidic) of the insect gut.
Q4
Bacillus thuringiensis strains have been used for designing novel
✓ Correct answer: d) Bioinsecticidal plants
ExplanationThe correct answer is: D. bioinsecticidal plants Bacillus thuringiensis (Bt) produces a Cry protein (crystal protein) that is toxic to certain insect pests.Genes coding for this protein (Cry genes) have been inserted into crops like cotton, maize, and brinjal to make them resistant to insect pests.Such crops are called bioinsecticidal plants because they produce their own insecticide naturally.Other options (biofertilizers, bio- metallurgical, bio-mineralization) are not related to Bt.
Q5
Golden rice is a promising transgenic crop. When released for cultivation, it will help in
✓ Correct answer: b) Alleviation of vitamin A deficiency
ExplanationThe correct answer is: B. alleviation of vitamin A deficiency Golden rice is a transgenic rice engineered to produce β-carotene, which is a precursor of vitamin A. Its cultivation helps combat vitamin A deficiency, especially in populations where rice is the staple food.It is not meant for fuel production, pest resistance, or herbicide tolerance.
Q6
Cry I endotoxins obtained from Bacillus thuringiensis are effective against
✓ Correct answer: b) Bollworms
ExplanationThe correct answer is: B. bollworms Cry I endotoxins produced by Bacillus thuringiensis are specifically toxic to lepidopteran insects.Bollworms (cotton pests) belong to Lepidoptera, so Cry I proteins are effective against them.Cry II → moths & butterflies Cry III → beetles Cry IV → mosquitoes So, the correct option is bollworms.
Q7
A transgenic food crop which may help in solving the problem of night blindness in developing countries is
✓ Correct answer: b) Golden rice
ExplanationThe correct answer is: B. Golden rice Golden rice is a transgenic rice engineered to produce β-carotene, a precursor of vitamin A. Vitamin A deficiency causes night blindness, especially in developing countries.Hence, Golden rice helps in preventing night blindness.Other options are unrelated to vitamin A deficiency.
Q8
The bacterium Bacillus thuringiensis is widely used in contemporary biology as
✓ Correct answer: a) Insecticide
ExplanationThe correct answer is: A. insecticide Bacillus thuringiensis produces Cry (crystal) proteins that are toxic to insect pests.These proteins are used as biological insecticides and their genes are used in Bt crops.It is not used for dairy production, industrial enzyme production, or as a pollution indicator.
Q9
Bacillus thuringiensis forms protein crystals which contain insecticidal protein. This protein
✓ Correct answer: a) Binds with epithelial cells of midgut of the insect pest ultimately killing it
ExplanationBacillus thuringiensis (Bt) produces Cry proteins as crystal inclusions.When ingested by susceptible insects, these proteins are activated in the alkaline midgut, They bind to the epithelial cells of the midgut, forming pores in the membrane, This disrupts ion balance, leading to cell lysis and death of the insect.
Q10
Introduction of food plants developed by genetic engineering is not desirable because:
✓ Correct answer: d) There is danger of coming viruses, allergens and toxins with introduced crop.
ExplanationGenetically engineered food plants involve the transfer of foreign genes into crop plants.These introduced genes may sometimes produce novel proteins that act as allergens or toxins in humans.There is also a risk that viruses or harmful substances may be unintentionally transferred along with the gene.Such unexpected effects can pose health hazards to consumers.Therefore, the introduction of genetically engineered food plants is considered undesirable due to biosafety concerns.
Q11
Human insulin is being commercially produced from a transgenic species of
✓ Correct answer: c) Escherichia
ExplanationThe correct answer is: C. Escherichia Human insulin is commercially produced using recombinant DNA technology in transgenic Escherichia coli.The human insulin gene is inserted into E. coli, which then synthesizes insulin (Humulin).Rhizobium is used for nitrogen fixation, Saccharomyces for fermentation, and Mycobacterium is not used for insulin production.
Q12
The genetic defect-adenosine deaminase (ADA) deficiency may be cured permanently by
✓ Correct answer: b) introducing bone marrow cells producing (ADA) into cells at early embryonic stages
ExplanationThe correct answer is: B. introducing bone marrow cells producing ADA into cells at early embryonic stages ADA deficiency causes SCID.Enzyme replacement therapy (C) and periodic infusion of genetically engineered lymphocytes (D) are temporary treatments and must be repeated.Permanent cure is possible when a functional ADA gene is introduced at the early embryonic stage or into bone- marrow stem cells, so that all future cells express ADA.Option B best represents this permanent gene therapy approach.
Q13
An improved variety of transgenic basmati rice
✓ Correct answer: b) Gives high yield and is rich in vitamin A
ExplanationThe correct answer is: B. gives high yield and is rich in vitamin A Improved transgenic rice varieties (like Golden rice) are developed to enhance nutritional quality, especially vitamin A (β-carotene) content, and may also show better yield.Complete resistance to all pests (C) is not possible, It still requires fertilizers (A is wrong), Loss of characteristic aroma of basmati is not a goal (D is wrong).
Q14
Which of the following features of genetic code does allow bacteria to produce human insulin by recombinant DNA technology?
✓ Correct answer: d) Genetic code is nearly universal.
ExplanationThe genetic code is nearly universal, meaning the same codons specify the same amino acids in almost all organisms.Therefore, when the human insulin gene is introduced into bacteria, they can read the codons correctly and synthesize human insulin.
Q15
Bt cotton variety that was developed by the introduction of toxin gene of Bacillus thuringiensis (Bt) is resistant to
✓ Correct answer: a) Insect pests
ExplanationBacillus thuringiensis produces protein crystals containing toxic insecticidal proteins (Cry proteins).These toxins are specific to certain groups of insects (Lepidopterans, Coleopterans, Dipterans).Bt cotton specifically contains cry genes (like cryIAc and cryIIAb) that target and kill insect pests, specifically bollworms (Lepidopterans).It does not provide resistance against fungi or nematodes directly.
Q16
In gene therapy of Adenosine Deaminase (ADA) deficiency, the patient requires periodic infusion genetically engineered lymphocytes because:
✓ Correct answer: a) Genetically engineered lymphocytes are not immortal cells.
ExplanationThe correct answer is Genetically engineered lymphocytes are not immortal cells.In ADA deficiency, gene therapy involves modifying the patient’s lymphocytes to produce the functional ADA enzyme.However, these engineered lymphocytes have a limited lifespan and do not multiply indefinitely.Therefore, the patient requires periodic infusions of freshly modified lymphocytes to maintain sufficient ADA activity in the body.This ensures continuous breakdown of toxic metabolites that accumulate due to ADA deficiency.
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