UPSC CSE Prelims
Biotechnology Previous Year Questions (PYQs)
Showing solved Previous Year Questions for Chapter: Biotechnology
Topic Breakdown: Scroll →
Improper handling and storage of cereal grains and oilseeds result in the production of toxins known as aflatoxins which are not generally destroyed by normal cooking process. Aflatoxins are produced by
Detailed Explanation:
Aflatoxins are poisonous carcinogens produced by certain moulds, specifically Aspergillus flavus and Aspergillus parasiticus.
These moulds grow in soil, decaying vegetation, hay, and improperly stored grains and are not destroyed by normal cooking temperatures.
Consider the following minerals -
- Calcium
- Iron
- Sodium
Which of the minerals given above is/are required by the human body for the contraction of muscles?
Detailed Explanation:
Calcium triggers muscle contraction by binding to troponin, which allows actin-myosin interaction.
Iron enables oxygen transport via myoglobin and supports ATP production in mitochondria for sustained muscle contraction.
Sodium maintains membrane potential and initiates action potentials that trigger muscle fiber contraction.
All three minerals (Calcium, Iron, Sodium) are essential for muscle contraction. Hence, option 4 is correct.
Recombinant DNA technology (Genetic Engineering) allows genes to be transferred
- Across different species of plants.
- From animals to plants.
- From microorganisms to higher organisms.
Select the correct Solution using the codes given below.
Detailed Explanation:
✅ Statement 1 – Correct: Recombinant DNA technology enables gene transfer across different plant species to introduce desirable traits like disease resistance.
✅ Statement 2 – Correct: Animal genes can be transferred to plants; for example, antifreeze protein genes from cold-water fish have been introduced into tomatoes and strawberries for frost tolerance.
✅ Statement 3 – Correct: Genes from microorganisms are routinely transferred to higher organisms; Bacillus thuringiensis (Bt) genes from soil bacteria are transferred to crops like cotton and corn for pest resistance.
🧐 Not Sure What to Study Next?
Get a personalised study plan based on your goals, time and revision needs.
Which of the following statements is/are correct?
- Viruses lack enzymes necessary for the generation of energy.
- Viruses can be cultured in any synthetic medium.
- Viruses are transmitted from one organism to another by biological vectors only.
Select the correct answer using the codes given below.
Detailed Explanation:
✅ Statement 1 – Correct: Viruses lack metabolic machinery and enzymes for ATP generation; they depend entirely on host cells for energy production.
❌ Statement 2 – Incorrect: Viruses cannot be cultured in synthetic or artificial media; they require living host cells (bacteria, plants, animals, or cell cultures) for replication.
❌ Statement 3 – Incorrect: Viral transmission occurs through multiple routes – direct contact, respiratory droplets, contaminated water/food, airborne particles, fomites, and biological vectors (mosquitoes, ticks); vectors are not the only mode.
With reference to ‘stem cells’, frequently in the news, which of the following statements is/are correct?
- Stem cells can be derived from mammals only
- Stem cells can be used for screening new drugs
- Stem cells can be used for medical therapies
Detailed Explanation:
❌ Statement 1 – Incorrect: Stem cells are found in all multicellular organisms, not just mammals—including plants, vertebrates, and invertebrates.
✅ Statement 2 – Correct: Stem cells are used for drug screening by generating specific cell types to test safety and efficacy of new pharmaceutical compounds before clinical trials.
✅ Statement 3 – Correct: Stem cells have applications in regenerative medicine including bone marrow transplants for blood disorders and tissue/organ repair.
Consider the following kinds of organisms :
- Bacteria
- Fungi
- Flowering plants
Some species of which of the above kinds of organisms are employed as biopesticides?
Detailed Explanation:
Bacteria (e.g., Bacillus thuringiensis) produce toxins that kill specific insects and are widely used as biopesticides.
Fungi (e.g., Beauveria bassiana, Metarhizium anisopliae) infect and kill pests through parasitism.
Flowering plants (e.g., Chrysanthemum producing pyrethrin, Neem with azadirachtin) contain natural insecticidal compounds used as biopesticides.
All three organism types are employed as biopesticides.
Other than resistance to pests, what are the prospects for which genetically engineered plants have been created?
- To enable them to withstand drought
- To increase the nutritive value of the produce
- To enable them to grow and do photosynthesis in spaceships and space stations
- To increase their shelf life
Select the correct answer using the codes given below:
Detailed Explanation:
✅ Statement 1 – Correct: Drought-resistant crops like drought-tolerant maize and water-efficient rice have been developed by introducing genes that enable water conservation and stress tolerance.
✅ Statement 2 – Correct: Golden Rice (fortified with Vitamin A), iron-biofortified crops, and protein-enhanced legumes demonstrate increased nutritive value through genetic engineering.
❌ Statement 3 – Incorrect: Growing plants in spaceships and space stations relies on controlled environment agriculture, not genetic engineering; NASA experiments use conventional plant varieties adapted through breeding, not GM technology.
✅ Statement 4 – Correct: Flavr Savr tomato (first GM food approved in 1994) and other crops have been engineered with delayed ripening genes to increase shelf life and reduce post-harvest losses.
What are the reasons for the people’s resistance to the introduction of Bt brinjal in India?
- Bt brinjal has been created by inserting a gene from a soil fungus into its genome.
- The seeds of Bt brinjal are terminator seeds and therefore, the farmers have to buy the seeds before every season from the seed companies.
- There is an apprehension that the consumption of Bt brinjal may have an adverse impact on health.
- There is some concern that the introduction of Bt brinjal may have an adverse effect on biodiversity.
Select the correct answer using the codes given below:
Detailed Explanation:
❌ Statement 1 – Incorrect: Bt brinjal is created by inserting the Cry1Ac gene from Bacillus thuringiensis, a soil bacterium, not a fungus, to provide resistance against the Brinjal Fruit and Shoot Borer (BFSB).
❌ Statement 2 – Incorrect: Bt brinjal seeds are not terminator seeds; they do not contain Genetic Use Restriction Technology (GURT) that prevents seed saving and reuse.
✅ Statement 3 – Correct: Major resistance stems from apprehensions about adverse health impacts, including concerns about allergenicity, toxicity, and lack of long-term independent safety studies on human consumption.
✅ Statement 4 – Correct: India is a center of origin and diversity for brinjal; concerns exist that cross-pollination with wild and local varieties could lead to genetic contamination and loss of indigenous biodiversity.