Prelims · Science & technology · 30 questions

Biotechnology & genetics

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Prelims 2019 · Q57

Medium

Consider the following statements:

1.According to the Indian Patents Act, a biological process to create a seed can be patented in India.
2.In India, there is no Intellectual Property Appellate Board.
3.Plant varieties are not eligible to be patented in India.

Which of the statements given above is/are correct?

Answer & explanation

Answer: (c) 3 only

Only statement 3 is correct. Section 3(j) of the Patents Act, 1970 rules out plants, seeds, varieties and essentially biological processes as patentable inventions. An Intellectual Property Appellate Board did exist when the question was set in 2019.

✗ 1. Section 3(j) treats seeds, varieties and species, and processes that are essentially biological, as non-inventions, so a biological method of making a seed cannot be patented.
✗ 2. In 2019 the Intellectual Property Appellate Board (IPAB) was still in existence, so the statement was wrong at the time.
✓ 3. Section 3(j) excludes plant varieties from patenting. New plant varieties are protected under the separate Protection of Plant Varieties and Farmers' Rights Act, 2001.
• Since then The Tribunals Reforms Act, 2021 (13 August 2021) lists the IPAB among the bodies it wound up, with pending cases transferred to the courts. Statement 2 would now read differently, but the answer for the 2019 paper stands.

Remember · Patents Act, section 3(j): plants, seeds, varieties and essentially biological processes are not patentable; plant varieties go to the PPV&FR Act, 2001.

Sources

The Patents Act, 1970, section 3(j) (as amended up to 1 August 2024), Indian Patent Office ↗ “plants and animals in whole or any part thereof other than micro-organisms but including seeds, varieties and species and essentially biological processes for production or propagation of plants and animals”
The Tribunals Reforms Act, 2021, Second Schedule, Department of Revenue ↗ “Intellectual Property Appellate Board under Trade Marks Act, 1999 (47 of 1999). … Any appeal, application or proceeding pending before the Tribunal, Appellate Tribunal or other Authorities specified in the Second Schedule”

Question and answer: UPSC's official GS Paper I (2019, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 30 Sept 2026 (how we verify). Permalink ·

Prelims 2019 · Q92

Easy

The word 'Denisovan' is sometimes mentioned in media in reference to

Answer & explanation

Answer: (b) an early human species

Denisovans are an early human group (an archaic hominin population of the Late Pleistocene) first identified from DNA taken from a finger bone found in Denisova Cave in southern Siberia. The name has nothing to do with dinosaurs, a cave system in North-East India or a geological period.

✓ (b) In 2010 researchers sequenced the genome of an archaic hominin from a finger bone found in Denisova Cave in southern Siberia, and named this hominin population 'Denisovans'. Their DNA shows they shared a common origin with Neanderthals.
✗ (a) Denisovans were hominins, that is, relatives of modern humans, not dinosaurs.
✗ (c) Denisova Cave lies in southern Siberia, not in North-East India.
✗ (d) 'Denisovan' names a human population, not a geological period.

Remember · Denisovans: an archaic early human group, first identified in 2010 from DNA of a finger bone in Denisova Cave, southern Siberia; related to Neanderthals.

Sources

Reich et al., Genetic history of an archaic hominin group from Denisova Cave in Siberia, Nature 468 (2010) (NIH PMC copy), abstract ↗ “Using DNA extracted from a finger bone found in Denisova Cave in southern Siberia, we have sequenced the genome of an archaic hominin to about 1.9-fold coverage. … We designate this hominin population ‘Denisovans’ and suggest that it may have been widespread in Asia during the Late Pleistocene epoch.”

Question and answer: UPSC's official GS Paper I (2019, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 1 Oct 2026 (how we verify). Permalink ·

Prelims 2019 · Q93

Hard

With reference to the recent developments in science, which one of the following statements is not correct?

Answer & explanation

Answer: (a) Functional chromosomes can be created by joining segments of DNA taken from cells of different species.

UPSC's official answer: (a) · the answer UPSC accepted, and the one that counts in the exam

What we believe: no option fits strictly

Statements (b), (c) and (d) are textbook techniques: recombinant DNA 'created in vitro', PCR copying DNA 'in vitro', and cell culture. By elimination (a) is the only candidate, which is how UPSC's key arrives at it.
But (a) is also an established fact. A yeast artificial chromosome (YAC) joins yeast centromere, telomere and origin sequences to DNA from another organism, and the yeast cell copies the construct as a chromosome: 'as the yeast cells grow and divide, they amplify the YAC DNA' (NHGRI).
NCERT itself names YACs as working vectors of the Human Genome Project: 'the vectors were called as BAC (bacterial artificial chromosomes), and YAC (yeast artificial chromosomes)'. A chromosome built from yeast and foreign DNA that replicates in a cell is a functional chromosome made from the DNA of different species.
On a strict reading none of the four statements is incorrect; UPSC's key stands by elimination, treating (a) as the overstatement.

UPSC's key marks (a), and in the exam (a) is the option to mark, since the other three are familiar textbook techniques. Exam lesson: when three options are standard textbook facts, the fourth, least familiar claim is the one UPSC will mark.

NIH National Human Genome Research Institute, Talking Glossary: Yeast Artificial Chromosome (YAC) ↗“Yeast artificial chromosome (YAC) is a human-engineered DNA molecule used to clone DNA sequences in yeast cells. YACs are often used in connection with the mapping and sequencing of genomes.”
NIH National Human Genome Research Institute, Talking Glossary: YAC, how the construct replicates in yeast ↗“The YACs, with their inserted DNA, are then taken up by yeast cells. As the yeast cells grow and divide, they amplify the YAC DNA”
NCERT Class 12 Biology, Ch 5 Molecular Basis of Inheritance (Human Genome Project) ↗“The commonly used hosts were bacteria and yeast, and the vectors were called as BAC (bacterial artificial chromosomes), and YAC (yeast artificial chromosomes).”

This box is Minimalist IAS's analysis, with its sources; it does not change UPSC's answer.

UPSC's key treats statement (a) as the one that is not correct. Statements (b), (c) and (d) each name an established laboratory technique: recombinant DNA made in vitro, copying of DNA outside a cell by PCR, and plant and animal cell culture. Statement (a) claims more, that a working chromosome is created simply by joining DNA pieces from different species; the key treats that as an overstatement, since such splicing yields recombinant DNA, a molecule, not by itself a functioning chromosome.

✓ (a) UPSC's key marks this as the statement that is not correct. The key's reading: joining DNA segments from different species is the making of recombinant DNA, whereas a functional chromosome is an organised structure of DNA and proteins with its own origins, centromere and telomeres, and a splice of foreign DNA is not treated as creating one. By elimination too, (a) is the only candidate, since the other three are textbook techniques.
✗ (b) This statement is true. NCERT describes recombinant DNA, a new combination of DNA made in vitro by joining cut DNA pieces with the enzyme DNA ligase.
✗ (c) This statement is true. In the polymerase chain reaction (PCR), multiple copies of a DNA segment are synthesised in vitro, that is, outside a living cell.
✗ (d) This statement is true. Plant and animal cells can be grown outside the body in a nutrient-rich medium, where they grow and multiply; this is cell culture.

Remember · Lab techniques that are real: recombinant DNA (joined in vitro), PCR (copying DNA outside cells) and cell culture (cells dividing in dishes). UPSC's key treats 'creating a functional chromosome by splicing DNA from different species' as the overstatement.

📘 Read it in NCERT: Class 12 Biology, Ch 9 (practise this chapter) · Class 12 Biology, Ch 9 (practise this chapter) · Class 9 Exploration, Ch 2 (practise this chapter) · Class 12 Biology, Ch 5 (practise this chapter)

Sources

NCERT Class 12 · Biology, Chapter 9 “This makes a new combination of circular autonomously replicating DNA created in vitro and is known as recombinant DNA.”
NCERT Class 12 · Biology, Chapter 9 “PCR stands for Polymerase Chain Reaction. In this reaction, multiple copies of the gene (or DNA) of interest is synthesised in vitro”
NCERT Class 9 · Exploration, Chapter 2 “Scientists have developed methods to grow plant and animal cells outside the body in special conditions. This is called cell culture.”
NCERT Class 12 · Biology, Chapter 5 “The commonly used hosts were bacteria and yeast, and the vectors were called as BAC (bacterial artificial chromosomes), and YAC (yeast artificial chromosomes).”
NIH National Human Genome Research Institute, Talking Glossary: Yeast Artificial Chromosome (YAC) ↗ “Yeast artificial chromosome (YAC) is a human-engineered DNA molecule used to clone DNA sequences in yeast cells.”

Question and answer: UPSC's official GS Paper I (2019, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 1 Oct 2026 (how we verify). Permalink ·

Prelims 2019 · Q96

Medium

'RNA interference (RNAi)' technology has gained popularity in the last few years. Why?

1.It is used in developing gene silencing therapies.
2.It can be used in developing therapies for the treatment of cancer.
3.It can be used to develop hormone replacement therapies.
4.It can be used to produce crop plants that are resistant to viral pathogens.

Select the correct answer using the code given below.

Answer & explanation

Answer: (a) 1, 2 and 4

RNA interference is a natural process in which a small RNA switches off a specific gene, so it is used for gene-silencing therapies, is being developed for cancer, and can make plants resist viruses. It is a way of switching genes off, not of supplying a hormone, so statement 3 does not fit.

✓ 1. Synthetic small interfering RNAs use RNAi to modulate gene function. The world's first RNAi drug, for a rare genetic liver disorder, has been approved.
✓ 2. Anticancer RNAi drugs are in development and have reached early clinical trials, although delivering them to tissues other than the liver remains a challenge.
✗ 3. Hormone replacement therapy supplies a hormone the body lacks. RNAi works by silencing a specific gene or mRNA, so it is not the basis of such therapies.
✓ 4. Plants can be engineered to carry sequences that target viral genes, so that RNAi silences the invading virus. NCERT notes that RNAi is a cellular defence that can be triggered by infection with RNA-genome viruses, and describes transgenic RNAi used to make plants resistant to a nematode pest.

Remember · RNAi silences a specific mRNA. Uses: gene-silencing drugs, cancer therapies under development, and virus-resistant crops; it does not supply hormones.

📘 Read it in NCERT: Class 12 Biology, Ch 10 (practise this chapter) · Class 12 Biology, Ch 10 (practise this chapter) · Class 12 Biology, Ch 10 (practise this chapter)

Sources

NCERT Class 12 · Biology, Chapter 10 “RNAi takes place in all eukaryotic organisms as a method of cellular defense. This method involves silencing of a specific mRNA due to a complementary dsRNA molecule that binds to and prevents translation of the mRNA (silencing).”
NCERT Class 12 · Biology, Chapter 10 “The source of this complementary RNA could be from an infection by viruses having RNA genomes or mobile genetic elements (transposons) that replicate via an RNA intermediate.”
NCERT Class 12 · Biology, Chapter 10 “The consequence was that the parasite could not survive in a transgenic host expressing specific interfering RNA.”
Mary Ann Liebert / NIH PMC, RNA Interference-Based Cancer Drugs: The Roadblocks, and the Delivery of the Promise, abstract ↗ “Nucleic acid-based therapeutics like synthetic small interfering RNAs have been exploited to modulate gene function, taking advantage of RNA interference (RNAi), an evolutionally conserved biological process. Recently, the world's first RNAi drug was approved for a rare genetic disorder in the liver. … In this study, we discuss the critical design considerations in anticancer RNAi drug development, insights gained from initial clinical trials”
RNA Interference: Promising Approach to Combat Plant Viruses (NIH PMC), abstract ↗ “This natural RNAi pathway could introduce transgenes targeting various viral genes to induce gene silencing.”

Question and answer: UPSC's official GS Paper I (2019, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 1 Oct 2026 (how we verify). Permalink ·

Prelims 2019 · Q99

Easy

What is Cas9 protein that is often mentioned in news?

Answer & explanation

Answer: (a) A molecular scissors used in targeted gene editing

Cas9 is an enzyme that cuts DNA at a spot chosen by a guide RNA, which is why it is called molecular scissors. It is the cutting tool of CRISPR-Cas9 gene editing.

✓ (a) The guide RNA carries the address of the target DNA and Cas9 makes the cut there. Once the DNA is cut, the cell's repair process can be used to change the gene.
✗ (b) Cas9 is a cutting enzyme, not a sensor. Some diagnostic tests borrow it, but the protein itself is not a biosensor.
✗ (c) Cas9 is a protein (an enzyme), not a gene. It can be used to edit genes, including those that help plants resist pests, but it is not that gene.

Remember · CRISPR-Cas9: a guide RNA finds the DNA address and the Cas9 enzyme, the 'molecular scissors', cuts it.

Sources

PIB, Ministry of Science & Technology: CRISPR gene-editing possible in temperature sensitive organisms, plants & crop varieties (3 Nov 2022) ↗ “the associated Cas9 enzyme, which acts as molecular scissors to cut DNA at a location specified by a guide RNA, can bind to and cut the target DNA at very low temperatures.”

Question and answer: UPSC's official GS Paper I (2019, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 30 Sept 2026 (how we verify). Permalink ·

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Class 12 Biology, Chapter 10cited in 3 explanations
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Biotechnology & genetics

Prelims 2019 · Q57

Prelims 2019 · Q92

Prelims 2019 · Q93

Prelims 2019 · Q96

Prelims 2019 · Q99

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