Biotechnology and its Applications — Class 12 MCQs with Answers

Biotechnology and its Applications — important questions & MCQs with answers (Class 12 Biology)

6 solved questions from this chapter's difficulty levels, each with its answer and explanation. Tap an option to check yourself.

0 of 6 answered

1. Q1 of 6Easy

   Bt cotton resists:

   AColdBDroughtCBollworm pestsDSalinity only
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   Answer: Bollworm pests

   Explanation: Bt cotton carries a cry gene from Bacillus thuringiensis, letting the plant make its own Cry protein toxic to bollworm larvae — it's pest resistance, not tolerance to cold, drought or salinity.

2. Q2 of 6Easy

   Recombinant insulin (Humulin) is produced in:

   APlants onlyBCattle pancreasCPig liverDE. coli (bacteria)
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   Answer: E. coli (bacteria)

   Explanation: Humulin is made by inserting the human insulin gene into E. coli, which then synthesises the A and B chains — not extracted from pig or cattle pancreas, avoiding animal-insulin allergies.

3. Q3 of 6Medium

   The Bt protoxin becomes an active toxin in the insect gut because the gut is:

   AAcidicBAlkaline, which solubilises the crystal protoxinCNeutral and dryDCold
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   Answer: Alkaline, which solubilises the crystal protoxin

   Explanation: The Bt protoxin crystal is insoluble at the near-neutral pH of most environments but dissolves in the insect midgut's alkaline conditions, releasing the toxin only once ingested — not in acidic or dry conditions.

4. Q4 of 6Medium

   Gene therapy aims to:

   ATreat genetic disorders by inserting/modifying genesBBuild musclesCLose weightDCool body
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   Answer: Treat genetic disorders by inserting/modifying genes

   Explanation: Gene therapy corrects a genetic disorder by inserting a functional gene, or modifying a faulty one, into a patient's cells — the first success, in 1990, treated ADA deficiency (SCID), not muscle-building.

5. Q5 of 6Hard

   Golden rice is engineered to produce:

   AIron onlyBβ-carotene (Vitamin A precursor)CProtein onlyDSugar
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   Answer: β-carotene (Vitamin A precursor)

   Explanation: Golden rice carries phytoene synthase and other carotenoid-pathway genes (from daffodil/maize plus a bacterium) so its endosperm accumulates β-carotene, the Vitamin A precursor — not iron or protein.

6. Q6 of 6Hard

   Monoclonal antibodies are:

   ALipidsBRandom mixtureCIdentical antibodies from a single B-cell cloneDCarbohydrates
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   Answer: Identical antibodies from a single B-cell clone

   Explanation: Monoclonal antibodies come from a single B-cell clone fused with a myeloma cell via hybridoma technology, so every molecule is identical and binds one epitope — unlike the mixed antibodies in normal serum.

Biotechnology and its Applications notes: key concepts (Class 12 Biology)

Biotechnology applications: transgenic crops like Bt cotton, RNAi pest resistance and biofortified Golden Rice; recombinant therapeutics — human insulin (Humulin) and gene therapy for ADA deficiency; molecular diagnostics by PCR and ELISA; transgenic animals; and the ethics of GMOs and biopiracy under GEAC oversight.

GMO

Genetically Modified Organism — a plant, animal or microbe with altered genes; engineered to resist pests/stress, improve nutrition or make useful proteins.

Bt cotton

Carries cry genes from Bacillus thuringiensis; the crystal protoxin becomes an active toxin in the insect's alkaline gut, killing bollworm larvae.

Cry proteins

Insecticidal proteins coded by cry genes; cryIAc and cryIIAb kill cotton bollworms and cryIAb kills corn borer — each is specific to certain insects.

RNA interference

RNAi silences a specific mRNA using complementary dsRNA; used to make tobacco resistant to the nematode Meloidogyne by silencing its genes.

Recombinant insulin

Humulin — human insulin made in E. coli; the A and B chains are produced separately and joined by disulphide bonds (no immune reaction, unlike animal insulin).

Proinsulin

The insulin precursor with an extra C-peptide, removed to form mature two-chain insulin; recombinant methods bypass it by making the chains separately.

Gene therapy

Correcting a genetic defect by inserting a normal gene; first done in 1990 for a girl with ADA (adenosine deaminase) deficiency using her lymphocytes.

Molecular diagnostics

PCR detects a pathogen's nucleic acid very early (HIV before antibodies form); ELISA detects antigen/antibody; a labelled probe finds a complementary sequence.

Golden Rice

Biofortified rice engineered to make β-carotene (provitamin A) to combat vitamin-A deficiency; it carries genes from daffodil and a soil bacterium.

Biofortification

Breeding or engineering crops for higher vitamins, minerals or protein to improve public health; Golden Rice is a leading example.

Transgenic animals

Animals carrying a foreign gene; used for study, safety testing and pharming — Rosie the cow gave milk enriched with a human protein (molecular farming).

Biopiracy

Use of bio-resources or traditional knowledge by companies without authorisation or benefit-sharing; e.g., patent attempts on neem, turmeric and basmati.

GEAC

Genetic Engineering Appraisal Committee — India's body that approves GM research and judges the safety of releasing GMOs for public use.

Monoclonal antibodies

Identical antibodies from a single clone; used in diagnosis and in targeted cancer therapy to bind specific tumour antigens.