Biology, health and biotechnology: previous-year questions
68 real UPSC Prelims questions (2011–2026) with the official answer and a clear explanation. 12 of them came in the last five papers.
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Which of the following statements with regard to genetic medicine is/are correct ?
- 1. Genetic medicines correct/compensate for the faulty genes responsible for disease.
- 2. Engineered viruses and lipid nanoparticles are used as carriers of the genetic medicine.
- 3. Genetic medicines alter the entire DNA sequence.
Select the answer using the code given below :
Answer (c) & explanation
Statements 1 and 2 are correct (c). Statement 1 is right: genetic medicines correct or make up for the faulty genes behind a disease, by adding a working copy, silencing a bad gene or editing a small stretch. Statement 2 is right: they are delivered by engineered viruses, such as AAV, or lipid nanoparticles, the carrier used in mRNA vaccines. Statement 3 is wrong: no therapy rewrites the entire genome. So options (a), (b) and (d) fail.
Notice India's progress: its first home-grown CAR-T cell therapy for cancer, NexCAR19 (2023), and a successful gene therapy trial for haemophilia at CMC Vellore. CRISPR-based Casgevy was the first approved gene-editing cure, for sickle cell disease.
Answer as per the official UPSC answer key.
Which of the following statements with regard to GenomeIndia Project is/are correct ?
- 1. It is a part of the Human Genome Project.
- 2. The project is funded by the Department of Biotechnology (DBT), Government of India.
- 3. Its primary aim is to build a catalogue of genetic diversity of the Indian population.
Select the answer using the code given below :
Answer (b) & explanation
Statements 2 and 3 are correct (b). Statement 2 is right: GenomeIndia (2020) is funded by the Department of Biotechnology. Statement 3 is right: it sequenced 10,000 genomes from many Indian communities to build a catalogue of the country's genetic variation, and the data was released in 2025. Statement 1 is wrong: the international Human Genome Project was a separate effort that ended in 2003. So options (a), (c) and (d) fail.
Notice the uses: finding gene variants behind diseases common in India, such as sickle cell and thalassaemia, and building personalised medicine. The data is stored at the Indian Biological Data Centre in Faridabad. A larger follow-up aims to sequence one million genomes.
Answer as per the official UPSC answer key.
Consider the following pairs :
| Plant | Description
| I. Cassava | Woody shrub
| II. Ginger | Herb with pseudostem
| III. Malabar spinach | Herbaceous climber
| IV. Mint | Annual shrub
| V. Papaya | Woody shrub
How many of the above pairs are correctly matched?
Answer (b) & explanation
Three pairs are correctly matched (b). Pair I is right: cassava is a woody shrub grown for its starchy roots. Pair II is right: ginger is a herb whose leafy "stem" is a pseudostem of rolled leaf sheaths above the rhizome. Pair III is right: Malabar spinach is a soft, herbaceous climber. Pair IV is wrong: mint is a perennial herb, not an annual shrub. Pair V is wrong: papaya is a soft-stemmed, tree-like plant, not a woody shrub.
Notice the term pseudostem: the banana plant also has one, which is why it is a giant herb, not a tree. Cassava, also called tapioca, is a major crop in Kerala and a staple food across Africa.
Answer as per the official UPSC answer key.
With reference to monoclonal antibodies, often mentioned in news, consider the following statements :
- I. They are man-made proteins.
- II. They stimulate immunological function due to their ability to bind to specific antigens.
- III. They are used in treating viral infections like that of Nipah virus.
Which of the statements given above are correct?
Answer (d) & explanation
All three statements are correct (d). Statement I is right: monoclonal antibodies are man-made proteins, lab-made copies of one antibody. Statement II is right: each binds one specific antigen, marking the target for the immune system or blocking it. Statement III is right: they are used against viral infections; Kerala has used the monoclonal antibody m102.4 against Nipah under compassionate use. So options (a), (b) and (c) fail.
Notice their wide use: in cancer (such as trastuzumab for breast cancer), autoimmune diseases, and COVID-19. They are costly, so making biosimilars at home is a goal of India's biotech policy. The method of making them, hybridoma, won the 1984 Nobel Prize.
Answer as per the official UPSC answer key.
Consider the following statements :
- I. No virus can survive in ocean waters.
- II. No virus can infect bacteria.
- III. No virus can change the cellular transcriptional activity in host cells.
How many of the statements given above are correct?
Answer (d) & explanation
None of the statements is correct (d). Each "no virus" statement is false. Statement I is wrong: seawater is full of viruses, millions in every millilitre; they kill much of the plankton daily and recycle nutrients. Statement II is wrong: bacteriophages are viruses that infect bacteria. Statement III is wrong: viruses routinely take over the host's transcription machinery to make their own proteins. So options (a), (b) and (c) fail.
Notice the medical use of phages: phage therapy is being tried against antibiotic-resistant bacteria, a growing threat called AMR. Viruses are not truly alive outside a host cell. Some viruses, like HPV, can even cause cancer by changing how host genes are switched on.
Answer as per the official UPSC answer key.
Which one of the following is synthesised in human body that dilates blood vessels and increases blood flow ?
Answer (a) & explanation
Nitric oxide dilates blood vessels (a). The inner lining of blood vessels makes nitric oxide (NO) from the amino acid arginine. NO relaxes the smooth muscle in vessel walls, which widens them and increases blood flow, lowering blood pressure. Nitroglycerine for angina and drugs like sildenafil work through this pathway. Option (b) is wrong: nitrous oxide is laughing gas, used in anaesthesia and a greenhouse gas. Option (c) is wrong: nitrogen dioxide is a toxic air pollutant from vehicles. Option (d) is wrong: nitrogen pentoxide is an industrial chemical, not made by the body.
Notice that the discovery of NO as a body signal won the 1998 Nobel Prize in Medicine. Beetroot and leafy greens supply nitrates that the body turns into NO.
Answer as per the official UPSC answer key.
‘Wolbachia method’ is sometimes talked about with reference to which one of the following?
Answer (a) & explanation
The Wolbachia method is used to control viral diseases spread by mosquitoes (a). Wolbachia is a common bacterium found in many insects. When it is put into Aedes aegypti mosquitoes, it stops dengue, Zika and chikungunya viruses from multiplying inside them. Infected females pass it to their young, so it spreads through the wild mosquito population over time. Options (b), (c) and (d) are about crop residues, bioplastics and biochar, which have nothing to do with it.
Notice the results: the World Mosquito Program has cut dengue sharply in trial cities such as Yogyakarta in Indonesia. India's ICMR developed its own Wolbachia strains of Aedes mosquitoes in 2024. Another approach releases sterile male mosquitoes.
Answer as per the official UPSC answer key.
‘Microsatellite DNA’ is used in the case of which one of the following?
Answer (a) & explanation
Microsatellite DNA is used to study evolutionary relationships (a). Microsatellites are short DNA sequences, two to six letters long, repeated many times in a row, such as CACACA. The number of repeats varies a lot between individuals and populations. That makes them useful for DNA fingerprinting, paternity tests, wildlife forensics, population genetics and studying evolutionary relationships among species. Option (b) is about stem cells, option (c) about tissue culture and option (d) about clinical trials. "Satellite" here has nothing to do with space.
Notice India's use: the Wildlife Institute of India and CCMB's LaCONES lab use such markers to identify tiger individuals from scat and catch poachers. They also help breeding programmes avoid inbreeding.
Answer as per the official UPSC answer key.
Consider the following statements :
- 1. Biofilms can form on medical implants within human tissues.
- 2. Biofilms can form on food and food processing surfaces.
- 3. Biofilms can exhibit antibiotic resistance.
Which of the statements given above are correct ?
Answer (d) & explanation
All three statements are correct (d). A biofilm is a colony of microbes stuck to a surface inside a slimy matrix they make themselves. Statement 1 is right: biofilms form on catheters, artificial joints and other medical implants, causing hard-to-treat infections. Statement 2 is right: they form on food and food-processing surfaces, spreading germs such as Listeria. Statement 3 is right: the matrix shields the bacteria, making them far more resistant to antibiotics, sometimes 1,000 times more.
Notice the everyday example: dental plaque is a biofilm. Biofilms also clog pipes and harm ship hulls. They add to the problem of antimicrobial resistance, which the WHO lists among the top global health threats.
Answer as per the official UPSC answer key.
Consider the following statements in respect of probiotics :
- 1. Probiotics are made of both bacteria and yeast.
- 2. The organisms in probiotics are found in foods we ingest but they do not naturally occur in our gut.
- 3. Probiotics help in the digestion of milk sugars.
Which of the statements given above is/are correct ?
Answer (c) & explanation
Statements 1 and 3 are correct (c). Probiotics are live, helpful microbes taken in food or supplements. Statement 1 is right: most are bacteria, such as Lactobacillus and Bifidobacterium, and some are yeasts, such as Saccharomyces boulardii. Statement 2 is wrong: the same kinds of microbes live naturally in our gut, as part of the gut microbiome. Statement 3 is right: lactobacilli make the enzyme lactase, which helps digest lactose, the milk sugar, easing lactose intolerance.
Notice the related terms: prebiotics are fibres that feed good bacteria, and synbiotics combine both. Curd (dahi), yoghurt and kefir are common probiotic foods. Probiotics are regulated in India by FSSAI.
Answer as per the official UPSC answer key.
In the context of vaccines manufactured to prevent COVID-19 pandemic, consider the following statements :
- 1. The Serum Institute of India produced COVID-19 vaccine named Covishield using mRNA platform.
- 2. Sputnik V vaccine is manufactured using vector based platform.
- 3. COVAXIN is an inactivated pathogen based vaccine.
Which of the statements given above are correct ?
Answer (b) & explanation
Statements 2 and 3 are correct (b). Statement 1 is wrong: Covishield, the Oxford–AstraZeneca vaccine made by the Serum Institute of India, uses a chimpanzee adenovirus vector (ChAdOx1), not mRNA. Statement 2 is right: Sputnik V, from Russia's Gamaleya Institute, uses two human adenovirus vectors (Ad26 and Ad5). Statement 3 is right: Bharat Biotech's Covaxin uses a whole inactivated virus that cannot cause disease.
Notice that the mRNA vaccines were Pfizer-BioNTech's, Moderna's and India's own Gemcovac (Gennova). The 2023 Nobel Prize in Medicine went to Katalin Karikó and Drew Weissman for the mRNA work. Covishield was withdrawn in 2024 after rare clotting side effects drew attention.
Answer as per the official UPSC answer key.
Which one of the following statements best describes the role of B cells and T cells in the human body ?
Answer (d) & explanation
B cells and T cells protect the body from pathogens (d). B and T lymphocytes are white blood cells that carry out adaptive immunity, which targets particular germs. B cells make antibodies that tag germs. Cytotoxic T cells kill infected cells, and helper T cells organise the whole response. Both keep a memory of past germs, which is why vaccines work. Option (a) is wrong: allergies come from an overreaction of the immune system, not protection from it. Option (b) is wrong: pain and inflammation are eased by drugs like painkillers. Option (c) is wrong: these cells drive immunity; they do not suppress it.
Notice that HIV attacks helper T cells (CD4). CAR-T therapy, now made in India, reprograms a patient's T cells to fight cancer.
Answer as per the official UPSC answer key.
Consider the following :
- 1. Bacteria
- 2. Fungi
- 3. Virus
Which of the above can be cultured in artificial/synthetic medium?
Answer (a) & explanation
Bacteria and fungi can be grown on artificial media (a). Item 1 is right: bacteria grow on nutrient agar or in broth, which supply sugars, salts and proteins. Item 2 is right: fungi also grow on artificial media, such as Sabouraud agar. Item 3 is wrong: viruses cannot reproduce on their own. They are not cells and have no machinery to make proteins, so they need living cells, such as cell cultures, embryonated eggs or animals. They cannot be grown on a cell-free synthetic medium.
Notice that most flu vaccines are still made by growing the virus in hens' eggs. The difference matters in medicine: antibiotics work against bacteria, not viruses. Bacteriophages are viruses that infect bacteria.
Answer as per the official UPSC answer key.
Consider the following statements :
- 1. Adenoviruses have single-stranded DNA genomes whereas retroviruses have double-stranded DNA genomes.
- 2. Common cold is sometime caused by an adenovirus whereas AIDS is caused by a retrovirus.
Which of the statements given above is/are correct?
Answer (b) & explanation
Only statement 2 is correct (b). Statement 1 is wrong on both counts. Adenoviruses have double-stranded DNA genomes. Retroviruses, such as HIV, carry single-stranded RNA, which an enzyme called reverse transcriptase copies into DNA that joins the host's genome. Statement 2 is right: adenoviruses cause some common colds, sore throats and conjunctivitis, while HIV, a retrovirus, causes AIDS.
Notice that most colds are caused by rhinoviruses, with adenoviruses and coronaviruses behind some. Adenoviruses are also used as vectors in vaccines such as Covishield. HIV treatment uses antiretroviral therapy (ART), and India's National AIDS Control Programme began in 1992.
Answer as per the official UPSC answer key.
The term ‘ACE2’ is talked about in the context of
Answer (d) & explanation
ACE2 relates to the spread of viral diseases (d). ACE2 (angiotensin-converting enzyme 2) is a protein on the surface of cells in the lungs, gut, heart and blood vessels. The spike protein of SARS-CoV-2 binds to ACE2 to enter cells, like a key in a lock. That is why it became central to the study of how COVID-19 spreads and harms the body. It is not a gene in GM plants (a), part of NavIC (b) or radio collars (c).
Notice that the earlier SARS virus (2002–03) also used ACE2. Normally, ACE2 helps control blood pressure. Many vaccines target the spike protein to stop it binding to ACE2.
Answer as per the official UPSC answer key.
With reference to recent developments regarding ‘Recombinant Vector Vaccines’, consider the following statements :
- 1. Genetic engineering is applied in the development of these vaccines.
- 2. Bacteria and viruses are used as vectors.
Which of the statements given above is/are correct?
Answer (c) & explanation
Both statements are correct (c). A recombinant vector vaccine puts a gene for a pathogen's antigen into a harmless carrier, which then makes the antigen inside the body and trains the immune system. Statement 1 is right: making the vaccine relies on genetic engineering. Statement 2 is right: the carrier can be a virus, such as the adenovirus in Covishield and Sputnik V, or a weakened bacterium, such as Salmonella or BCG.
Notice other COVID vaccine types: Covaxin used a whole inactivated virus; Pfizer and Moderna used mRNA; ZyCoV-D was the world's first DNA vaccine for people; Corbevax was a protein subunit vaccine. India also approved an intranasal vaccine (iNCOVACC).
Answer as per the official UPSC answer key.
In the context of hereditary diseases, consider the following statements :
- 1. Passing on mitochondrial diseases from parent to child can be prevented by mitochondrial replacement therapy either before or after in vitro fertilization of egg.
- 2. A child inherits mitochondrial diseases entirely from mother and not from father.
Which of the statements given above is/are correct?
Answer (c) & explanation
Both statements are correct (c). Statement 2 is right: mitochondria come only from the egg, because the sperm's mitochondria are destroyed after fertilisation. So mitochondrial DNA diseases pass down entirely from the mother. Statement 1 is right: mitochondrial replacement therapy swaps the mother's faulty mitochondria for healthy donor mitochondria. This can be done before fertilisation (spindle transfer) or after it (pronuclear transfer), with in vitro fertilisation. The child then carries DNA from three people, hence "three-parent babies".
Notice that the UK legalised the method in 2015, and in 2025 reported eight healthy babies born this way. Mitochondria are the cell's powerhouses, making energy as ATP.
Answer as per the official UPSC answer key.
Bollgard I and Bollgard II technologies are mentioned in the context of
Answer (b) & explanation
Bollgard refers to genetically modified crops (b). Bollgard is Monsanto's (now Bayer's) Bt cotton. Bollgard I carries the cry1Ac gene from the soil bacterium Bacillus thuringiensis, and Bollgard II adds cry2Ab. These genes make toxins that kill the bollworm, a major cotton pest. It is not about clonal propagation (a), growth substances (c) or biofertilisers (d).
Notice that Bt cotton, approved in 2002, is India's only commercially approved GM crop, though GM mustard (DMH-11) got environmental release approval in 2022. Pink bollworm has developed resistance, weakening Bt cotton. The GEAC under the Environment Ministry approves GM crops. India released two genome-edited rice varieties in 2025.
Answer as per the official UPSC answer key.
In the context of recent advances in human reproductive technology, “Pronuclear Transfer” is used for
Answer (d) & explanation
Pronuclear transfer prevents mitochondrial diseases (d). Mitochondria have their own small set of DNA, passed on only from the mother. Faults in it cause serious diseases of the muscles, brain and heart. In pronuclear transfer, the egg of the mother is fertilised by the father's sperm. The two pronuclei, holding the parents' main DNA, are moved into a donor egg that has healthy mitochondria and whose own nuclei have been removed. The child gets the parents' genes but healthy mitochondria, hence the term "three-parent babies". It is not normal IVF (a), editing of sperm-making cells (b), or turning stem cells into embryos (c).
The UK legalised the method in 2015. Notice that in 2025, UK doctors reported eight babies born using it.
Answer as per the official UPSC answer key.
Consider the following statements :
- 1. Genetic changes can be introduced in the cells that produce eggs or sperms of a prospective parent.
- 2. A person’s genome can be edited before birth at the early embryonic stage.
- 3. Human induced pluripotent stem cells can be injected into the embryo of a pig.
Which of the statements given above is/are correct ?
Answer (d) & explanation
All three statements are correct (d). Gene-editing tools such as CRISPR-Cas9 can change the DNA of germline cells, the cells that make eggs or sperm (1). Such changes would pass to future generations. A person's genome can be edited at the early embryo stage (2), as in the 2018 case of the Chinese scientist He Jiankui, who made the first gene-edited babies and was jailed. Human induced pluripotent stem (iPS) cells, made by reprogramming adult cells, have been injected into pig embryos to make human–pig chimeras (3), for research into growing human organs.
These are all technically possible but ethically debated. Notice the newer step: pig kidneys and hearts, genetically edited, were transplanted into living humans in the USA (2022–25).
Answer as per the official UPSC answer key.