This is a classic 'Term in News' question. While static books (NCERT) explain DNA and heredity, they don't cover specific new proteins like Cas9. This question rewards the 'Newspaper Reader' over the 'Bookworm'. If a science term is in the headlines (CRISPR was massive news), you must know its one-line functional analogy.
How this question is built
This question can be broken into the following sub-statements.
Tap a statement sentence to jump into its detailed analysis.
Statement 1
Is Cas9 protein a molecular "scissors" used for targeted gene editing?
Origin: Web / Current Affairs
Fairness: CA heavy
Web-answerable
"Once the gRNA binds to the target DNA, the Cas9 enzyme acts like molecular scissors, making a double-strand cut at the specified site (Doudna & Charpentier, 2014)."
Why this source?
- Explicitly describes Cas9 as acting "like molecular scissors" to make a double-strand cut at the targeted site.
- Connects the cut by Cas9 to targeted editing via guide RNA and cellular repair pathways that alter gene function.
"function of Cas9 has been manipulated to precisely insert or remove specific DNA fragments from a strand of genetic material, acting as a pair of molecular scissors."
Why this source?
- States Cas9 has been manipulated to insert or remove DNA fragments, describing it as "acting as a pair of molecular scissors."
- Frames Cas9's role directly in precision editing (inserting/removing DNA), matching the metaphor of molecular scissors for targeted editing.
"Site-specific DNA double-strand breaks (DSBs), which are induced by the Cas9 protein under the control of sg-RNA, trigger DNA repair mechanisms."
Why this source?
- Explains that Cas9, guided by sgRNA, induces site-specific DNA double-strand breaks (DSBs).
- Shows the mechanistic basis (targeted cleavage) by which Cas9 enables gene editing, supporting the "scissors" metaphor.
Indian Economy, Nitin Singhania .(ed 2nd 2021-22) > Chapter 9: Agriculture > GENETICALLY MODIFIED (GM) CROPS > p. 301
Strength: 5/5
“• According to WHO, Genetically Modified Organisms (GMO) are the plants, animals or microorganisms in which the hereditary material (DNA) is altered in a manner that does not happen normally by mating or potentially regular recombination. It is also known as modern biotechnology/gene technology.• When genetic modification of a plant is performed, foreign gene (transgene) or gene of some other organism is artificially inserted into the plant's own genes. This is gene modification.”
Why relevant
Defines genetic modification as altering hereditary material (DNA) and inserting foreign genes — showing that deliberate changes to DNA underlie gene editing.
How to extend
A student can combine this with the idea of a tool that makes precise DNA changes (e.g., a molecular 'scissor' that cuts DNA at chosen sites) to see why a DNA-cutting protein would be useful for targeted modification.
Science , class X (NCERT 2025 ed.) > Chapter 8: Heredity > 8.2.3 How do these Traits get Expressed? > p. 131
Strength: 4/5
“How does the mechanism of heredity work? Cellular DNA is the information source for making proteins in the cell. A section of DNA that provides information for one protein is called the gene for that protein. How do proteins control the characteristics that we are discussing here? Let us take the example of tallness as a characteristic. We know that plants have hormones that can trigger growth. Plant height can thus depend on the amount of a particular plant hormone. The amount of the plant hormone made will depend on the efficiency of the process for making it. Consider now an enzyme that is important for this process.”
Why relevant
Explains that a gene (DNA segment) encodes proteins and that enzymes influence biological traits, linking changes in DNA to changes in cellular function.
How to extend
Knowing DNA sections map to traits, a student could infer that cutting or altering a specific gene could change the encoded protein and thus the trait — suggesting a role for a precise DNA-cutting agent.
Science , class X (NCERT 2025 ed.) > Chapter 7: How do Organisms Reproduce? > 7.1 DO ORGANISMS CREATE EXACT COPIES OF THEMSEL THEMSELVES? > p. 113
Strength: 4/5
“Organisms look similar because their body designs are similar. If body designs are to be similar, the blueprints for these designs should be similar. Thus, reproduction at its most basic level will involve making copies of the blueprints of body design. In Class IX, we learnt that the chromosomes in the nucleus of a cell contain information for inheritance of features from parents to next generation in the form of DNA (Deoxyribo Nucleic Acid) molecules. The DNA in the cell nucleus is the information source for making proteins. If the information is changed, different proteins will be made. Different proteins will eventually lead to altered body designs.”
Why relevant
States that changing DNA information leads to different proteins and altered organisms, emphasizing that targeted DNA changes can have predictable effects.
How to extend
A student can reason that a molecular mechanism that makes targeted cuts or edits in DNA would enable those predictable changes, supporting the plausibility of a 'scissors' for editing.
Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 16: Conservation Efforts > 16.17. DNA BARCODING > p. 248
Strength: 4/5
“A MoU signed between Zoological Survey of India (ZSI), a subordinate organization under MoEF&CC, and International Barcode of Life (iBOL), a Canadian not-for-profit corporation. ZSI and iBOL have come together for further efforts in DNA barcoding, a methodology for rapidly and accurately identifying species by sequencing a short segment of standardized gene regions and comparing individual sequences to a reference database. iBOL is a research alliance involving nations that have committed both human and financial resources to enable expansion of the global reference database, the development of informatics platforms, and/or the analytical protocols needed to use the reference library to inventory, assess, and describe biodiversity.”
Why relevant
Describes DNA barcoding and sequencing of specific gene regions, highlighting that specific DNA sequences can be identified and targeted.
How to extend
Combining sequence-identification (targeting) with a DNA-modifying tool suggests how a sequence-specific 'cutting' protein could be directed to particular genes for editing.
Science , class X (NCERT 2025 ed.) > Chapter 8: Heredity > separate traits, shape and colour of seeds Figure 8.5 > p. 132
Strength: 3/5
“inherited. This is explained by the fact that each gene set is present, not as a single long thread of DNA, but as separate independent pieces, each called a chromosome. Thus, each cell will have two copies of each chromosome, one each from the male and female parents. Every germcell will take one chromosome from each pair and these may be of either maternal or paternal origin. When two germ cells combine, they will restore the normal number of chromosomes in the progeny, ensuring the stability of the DNA of the species. Such a mechanism of inheritance explains the results of the Mendel experiments, and is used by all sexually reproducing organisms.”
Why relevant
Explains that genes exist as discrete pieces (chromosomes) and that inheritance depends on specific DNA units, implying genes are addressable units.
How to extend
A student could extend this by noting that addressable gene units make it meaningful to target and cut particular DNA loci with a molecular tool to alter inheritance or traits.
Statement 2
Is Cas9 protein used as a biosensor for accurate detection of pathogens in patients?
Origin: Weak / unclear
Fairness: Borderline / guessy
Indirect textbook clues
Environment and Ecology, Majid Hussain (Access publishing 3rd ed.) > Chapter 8: Natural Hazards and Disaster Management > Dengue and Chikungunya > p. 79
Strength: 5/5
“Patients have complained of joint pains for much longer time periods; some as long as two years, depending on their age. Common laboratory tests for chikungunya virus isolation, and serological tests. Virus isolation provides the most defnitive diagnosis but takes 1–2 weeks for completion and must be carried out in Biosafety level 3 laboratories. Te technique involves exposing specifc cell-lines to samples from whole blood and identifying dengue/chikungunya virus-specifc responses. Dengue/Chikungunya virus is indigenous to tropical Africa and Asia, where it is transmitted to humans by the bite of infected mosquitoes, usually of the genus Aedes. Dengue is prevalent in parts of Asia (especially South and South-East Asia), countries of Equatorial Africa, South and Central America, Cuba and other island of West Indies.”
Why relevant
Describes laboratory diagnostic methods (virus isolation, serology) and the requirements (Biosafety level 3, specific cell-lines), highlighting that pathogen detection can rely on molecular/biological assays.
How to extend
A student could note that newer molecular diagnostics aim to be faster and safer than culture-based methods and therefore investigate whether Cas9-based assays provide rapid nucleic-acid detection suitable for clinical diagnostics.
Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 16: Conservation Efforts > 16.17. DNA BARCODING > p. 248
Strength: 5/5
“A MoU signed between Zoological Survey of India (ZSI), a subordinate organization under MoEF&CC, and International Barcode of Life (iBOL), a Canadian not-for-profit corporation. ZSI and iBOL have come together for further efforts in DNA barcoding, a methodology for rapidly and accurately identifying species by sequencing a short segment of standardized gene regions and comparing individual sequences to a reference database. iBOL is a research alliance involving nations that have committed both human and financial resources to enable expansion of the global reference database, the development of informatics platforms, and/or the analytical protocols needed to use the reference library to inventory, assess, and describe biodiversity.”
Why relevant
Explains DNA barcoding as sequencing short standardized gene regions to identify species, showing that sequence-based approaches are valid for accurate identification of organisms.
How to extend
One could extend this by reasoning that any tool (including Cas9) that recognizes specific nucleotide sequences might be adapted as a molecular diagnostic/biosensor for pathogen detection.
Science ,Class VIII . NCERT(Revised ed 2025) > Chapter 3: Health: The Ultimate Treasure > Snapshots > p. 42
Strength: 4/5
“They can often be prevented with healthy habits, lifestyle changes, and regular exercise.• Infectious diseases are caused by pathogens like bacteria, viruses, or worms.• Our immune system helps protect us from harmful pathogens.• Vaccines train the immune system using dead, weakened, or harmless parts of a germ to prevent disease.• Diagnosis and treatment are important for managing and curing diseases.”
Why relevant
Notes that diagnosis is important for managing infectious diseases and lists causes (bacteria, viruses) implying the need for accurate detection methods in clinical practice.
How to extend
A student could infer that because clinical management depends on accurate diagnostics, investigating whether Cas9-based detection meets clinical accuracy requirements is a logical next step.
Science ,Class VIII . NCERT(Revised ed 2025) > Chapter 3: Health: The Ultimate Treasure > Ability of the body to fight diseases > p. 37
Strength: 3/5
“Vaccines can be made in different ways—from weakened or dead pathogens (like viruses or bacteria), or from inactive or harmless parts of the pathogen. Some newer vaccines instruct our own body cells”
Why relevant
Mentions 'newer vaccines instruct our own body cells', indicating the existence and clinical use of recent molecular biotechnology approaches.
How to extend
This suggests a pattern where modern molecular tools (beyond classical vaccines/tests) are being translated to clinical use, so one might look for Cas9 as another biotechnology repurposed for diagnostics.
Science ,Class VIII . NCERT(Revised ed 2025) > Chapter 3: Health: The Ultimate Treasure > 3.4.1 How are communicable diseases caused and spread? > p. 32
Strength: 3/5
“All communicable diseases are caused by pathogens. These pathogens can enter our body through the air we breathe or by consuming contaminated food or water and more. But how do these pathogens spread from one person to another? One common way is through air, when an infected person coughs or sneezes, or through direct contact like shaking hands, or indirectly by sharing”
Why relevant
Explains routes and agents of communicable diseases, emphasizing the diversity of pathogens that diagnostics must detect.
How to extend
A student could use this to reason that an effective biosensor like Cas9 would need to target diverse pathogen nucleic acids and therefore check whether Cas9 systems have been adapted for multiple pathogen types.
Statement 3
Is Cas9 a gene that makes plants pest-resistant?
Origin: Web / Current Affairs
Fairness: CA heavy
Web-answerable
"CRISPR associated (Cas) proteins have been utilized recently for Genome editing in plants and animals modified pest-resistant plant cotton)."
Why this source?
- States that CRISPR-associated (Cas) proteins have been used for genome editing to produce pest-resistant plants.
- Implies Cas proteins (like Cas9) are tools applied to modify plants to confer pest resistance, not themselves plant resistance genes.
"CRISPR is used to target specific genes that play a role in susceptibility to diseases. Gene knockouts, one of the most common CRISPR applications, involve disabling or "knocking out" genes that make plants vulnerable to pathogens. By inactivating these genes, plants can become resistant to diseases without the need for external chemical inputs like pesticides."
Why this source?
- Explains CRISPR is used to target and disable genes that make plants susceptible, producing disease/pest resistance.
- Shows the role of CRISPR/Cas systems is to edit plant genes (knockouts/knock-ins) rather than being innate resistance genes themselves.
"scientists employed CRISPR-Cas9 to target and edit the SlGOLS gene, which is linked to the plant's susceptibility to TYLCV. By knocking out this gene, the researchers developed tomato plants that demonstrated increased resistance to the virus,"
Why this source?
- Provides a concrete example where researchers used CRISPR-Cas9 to edit a plant gene (SlGOLS) to increase virus resistance.
- Demonstrates Cas9 functions as a genome-editing tool to create resistance by altering plant genes, not as a resistance gene itself.
Indian Economy, Nitin Singhania .(ed 2nd 2021-22) > Chapter 9: Agriculture > GENETICALLY MODIFIED (GM) CROPS > p. 301
Strength: 5/5
“• According to WHO, Genetically Modified Organisms (GMO) are the plants, animals or microorganisms in which the hereditary material (DNA) is altered in a manner that does not happen normally by mating or potentially regular recombination. It is also known as modern biotechnology/gene technology.• When genetic modification of a plant is performed, foreign gene (transgene) or gene of some other organism is artificially inserted into the plant's own genes. This is gene modification.”
Why relevant
Gives a definition of GMOs and states that genetic modification involves inserting a foreign gene (transgene) into a plant to confer new traits.
How to extend
A student can use this rule to ask whether Cas9 is used as a transgene or as a tool for editing those transgenes to assess if it would itself be described as conferring pest resistance.
Indian Economy, Nitin Singhania .(ed 2nd 2021-22) > Chapter 9: Agriculture > 2019 > p. 359
Strength: 5/5
“GM mustard has the genes of a soil bacterium that give the plant the property of pest-resistance to a wide variety of pests. 2. GM mustard has the genes that allow the plant cross-pollination and hybridization. Which of the statements given above is/are correct? (b) 2 only (a) 1 and 3 only• (d) 1, 2 and 3 (c) 2 and 3 only• 17. With reference to agricultural soils, consider the following statements: • 1. A high content of organic matter in soil drastically reduces its water holding capacity. • 2. Soils do not play any role in the sulphur cycle.”
Why relevant
Provides a concrete example where genes from a soil bacterium were introduced into GM mustard and those genes give the plant pest-resistance.
How to extend
A student could compare the biological source and function of Cas9 with the example (bacterial gene conferring resistance) to judge plausibility that Cas9 might act similarly.
Science , class X (NCERT 2025 ed.) > Chapter 8: Heredity > 8.2.3 How do these Traits get Expressed? > p. 131
Strength: 4/5
“If this enzyme works efficiently, a lot of hormone will be made, and the plant will be tall. If the gene for that enzyme has an alteration that makes the enzyme less efficient, the amount of hormone will be less, and the plant will be short. Thus, genes control characteristics, or traits. If the interpretations of Mendelian experiments we have been discussing are correct, then both parents must be contributing equally to the DNA of the progeny during sexual reproduction. We have disscussed this issue in the previous Chapter. If both parents can help determine the trait in the progeny, both parents must be contributing a copy of the same gene.”
Why relevant
Explains the general principle that genes control characteristics or traits (e.g., enzyme efficiency affects plant height).
How to extend
Use this principle to recognize that for Cas9 to 'make' pest resistance it would need to encode a trait-altering product or enable changes that produce such a trait.
Environment and Ecology, Majid Hussain (Access publishing 3rd ed.) > Chapter 12: Major Crops and Cropping Patterns in India > Biotic: Living > p. 111
Strength: 4/5
“Genetic control: Te genetic control of pests involving releasing sterilised pests into the afected area. When these pests made with the female of their species, there are no ofspring, leading to a decline in the number of such pests. Genetic engineering: Te process of artifcially removing specifc genes from one organism and replacing them with genetic information from another. Geography: Te science that studies the interdependence among geographic areas, natural systems, processes, society, and cultural activities over space – a spatial science. Te fve themes of geographic education include: location, place, movement, regions, and human–Earth relationships. Geologic cycle: A general term characterising the vast cycling (hydrology, tectonic and rock) in and on the lithosphere.”
Why relevant
Mentions 'genetic engineering' as removing/replacing specific genes with information from another organism and also refers to genetic control methods for pest management.
How to extend
A student could consider whether Cas9 functions as the inserted trait or as a gene-editing tool used to alter other genes implicated in pest resistance.
Environment and Ecology, Majid Hussain (Access publishing 3rd ed.) > Chapter 2: PLANT AND ANIMAL KINGDOMS > 2.4 Environment and Ecology > p. 5
Strength: 3/5
“• (ii) Artifcial Selection: Artifcial selection occurs through human activities, when man creates a new environment. For instance, man develops new seeds to increase the yield of crops through artifcial measures such as cross-pollination and hybridisation. Such newly created hybrid seeds are disease and pest resistant and are capable for their adaptation to various types of soils and climatic conditions. Tis process may be benefcial for mankind at present, because it may solve the problem of shortage of food-grains through increased production. But it may prove disastrous in near future, when all natural plants of food crops will disappear from the surface of the Earth.• (iii) Isolation: Isolation also plays an important role in the evolution of morphologically diferentiated populations of species of plants.”
Why relevant
States that artificial selection and hybridisation can create seeds that are disease- and pest-resistant, showing multiple genetic routes to resistance.
How to extend
This suggests a student should distinguish between genes that directly encode resistance and techniques (or genes) used to create resistant varieties, and then see which category Cas9 fits.
Statement 4
Is Cas9 a herbicidal substance synthesized in genetically modified crops?
Origin: Web / Current Affairs
Fairness: CA heavy
Web-answerable
"Efficiency of CRISPR-Cas9 has been found to greatly increase when various components of the system including the entire CRISPR/Cas9 structure to Cas9-gRNA complexes delivered in assembled form rather than using transgenics. This has found particular value in genetically modified crops for mass commercialization."
Why this source?
- States CRISPR-Cas9 is used in genetically modified crops for mass commercialization, indicating Cas9-related technology appears in crop contexts.
- Describes delivery of Cas9 components (implying use as a genome-editing tool rather than a pesticide/herbicide).
"The commercialization of transgenic crops expressing CRISPR/Cas9 faces challenges in many countries, primarily due to development costs and restrictions imposed by regulatory systems for the field release of genetically modified organisms. CRISPR/Cas9 will introduce a lot of off-target mutations into the genome."
Why this source?
- Specifically mentions 'transgenic crops expressing CRISPR/Cas9', showing crops can express Cas9.
- Context discusses editing and off-target mutations, indicating Cas9's role is genome editing rather than acting as a chemical herbicide.
"Cas9 proteins select the correct location on the host's genome by utilizing the sequence to bond with base pairs on the host DNA. The sequence is not part of the Cas9 protein and as a result is customizable and can be independently synthesized."
Why this source?
- Describes Cas9 as a protein that 'selects the correct location on the host's genome' and binds to DNA, indicating a molecular editing function.
- Clarifies that the targeting sequence is separate from the Cas9 protein, supporting that Cas9 is an editing enzyme, not a herbicidal compound.
Indian Economy, Vivek Singh (7th ed. 2023-24) > Chapter 11: Agriculture - Part II > GM Mustard > p. 344
Strength: 5/5
“• Environmental activists and the Swadeshi Jagran Manch, an affiliate of the RSS, have opposed the move and urged the government to not give a final nod as there are several issues and concerns like: • 1. Studies have shown a strong correlation between growth of GM crops, the herbicides they promote and the diseases such as acute kidney injury, diabetes, Alzheimer's and cancer in the past 20 years in US. (17 of the 20 most developed countries including Japan, Russia, Israel and most Europe refuse to grow GM crops).• 2. The GM crops are said to be herbicide tolerant (i.e., one can use the herbicide to remove the herbs/weeds in GM crops).”
Why relevant
States GM crops are said to be herbicide tolerant and that GM growth is associated with use of herbicides — introduces the common trait 'herbicide tolerance' rather than that GM plants produce herbicides themselves.
How to extend
A student could use this to distinguish between (A) GM plants engineered to tolerate externally applied herbicides and (B) plants engineered to synthesize a herbicidal substance, and then check whether Cas9 fits either category.
Indian Economy, Nitin Singhania .(ed 2nd 2021-22) > Chapter 9: Agriculture > GENETICALLY MODIFIED (GM) CROPS > p. 301
Strength: 4/5
“• According to WHO, Genetically Modified Organisms (GMO) are the plants, animals or microorganisms in which the hereditary material (DNA) is altered in a manner that does not happen normally by mating or potentially regular recombination. It is also known as modern biotechnology/gene technology.• When genetic modification of a plant is performed, foreign gene (transgene) or gene of some other organism is artificially inserted into the plant's own genes. This is gene modification.”
Why relevant
Explains that genetic modification involves inserting foreign genes (transgenes) into a plant so the plant can express new traits/proteins.
How to extend
A student could reason that if Cas9 were expressed in a crop it would require a transgene encoding the Cas9 protein — then look up whether such constructs are used to make herbicides in planta.
Indian Economy, Nitin Singhania .(ed 2nd 2021-22) > Chapter 9: Agriculture > 9.16 Indian Economy > p. 302
Strength: 4/5
“• In 2016, GM mustard or Dhara Mustard Hybrid-11 (DMH-11) was cleared by GEAC for field trail. However, GEAC has demanded more tests of DMH-11 to allow its commercial cultivation. • "It is for reference that GEAC recommended the commercial release of Bt brinjal in 2007 but it was blocked by the government in 2010". The Biotechnology Regulatory Authority Bill, which envisages creating a regulatory body for uses of biotechnology products including GM organisms, is pending in the Parliament since 2008. Higher crop yields ensures food security. Reduced farm costs and increased farm Can contaminate other fields through cross- pollination. • Col1: Can withstand weather fluctuations and decrease the use of pesticides and herbicides. • Col3: There is a danger of allergens entering into the food chain.”
Why relevant
Mentions Bt brinjal and Bt as an example where GM crops express an insecticidal protein (Bt toxin), showing GM plants can be engineered to produce pesticidal proteins.
How to extend
By analogy, a student can ask whether Cas9 is used similarly as an in-plant pesticidal protein (and then compare Cas9's known function to Bt's mode of action).
Indian Economy, Vivek Singh (7th ed. 2023-24) > Chapter 11: Agriculture - Part II > 11.8 Genetically Modified (GM) Crops > p. 342
Strength: 3/5
“GM crops are plants whose DNA (a molecule that encodes the Genetic Information) has been modified using Genetic Engineering. The following are some benefits of GM crops: • More nutritional value• Resistance to bacteria, virus and other components that can damage the plant• Longer shelf life• Less costly GM foods and higher yields The Genetic Engineering Appraisal Committee (GEAC) is the apex body for regulating GM crops, in the Ministry of Environment and Forest under the Environment Protections Act 1986. At present, the government allows commercial production of only one GM crop which is BT cotton and is allowed since 2002.”
Why relevant
Defines GM crops as plants whose DNA is modified to confer traits like resistance to bacteria, viruses and other damaging agents — showing the typical goals of modification are resistance/safety and productivity.
How to extend
A student could use this to assess whether producing a herbicidal substance aligns with common GM crop objectives and then investigate Cas9's typical intended use in biotechnology.
Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 25: Agriculture > Beneficial effects of weeds > p. 365
Strength: 2/5
“Colonum occurs in rich soils while Cymbopogon denotes poor light soil and Sedges are found in ill-drained soils Genetically modified crops (GM crops, or biotech crops) are plants, the DNA of which has been modified using genetic engineering techniques, which are then used in agriculture.”
Why relevant
Gives a basic definition that GM crops have DNA altered using genetic engineering techniques — framing that any novel trait (including protein synthesis) would arise from deliberate genetic changes.
How to extend
A student can combine this with knowledge of what Cas9 does (a genome-editing nuclease) to judge plausibility of crops being engineered to synthesize Cas9 as a herbicide.
Pattern takeaway:
UPSC Science & Tech questions prioritize 'Functional Definitions' over technical mechanisms. They want to know if you understand the *application* of the technology (e.g., editing vs. sensing vs. pest resistance) rather than the biological pathway.
How you should have studied
- [THE VERDICT]: Sitter (Current Affairs). While the provenance score is low for static books, this was the most discussed biotech topic of the decade. Missing this means you aren't tracking S&T headlines.
- [THE CONCEPTUAL TRIGGER]: Biotechnology > Genome Editing Tools. The shift from 'Genetic Modification' (inserting foreign genes) to 'Gene Editing' (fixing existing genes).
- [THE HORIZONTAL EXPANSION]: Memorize the 'Biotech Toolbox': Zinc Finger Nucleases (ZFNs) & TALENs (Older editors), RNA Interference (Gene Silencing), CAR-T Therapy (Cancer), Mitochondrial Replacement (3-Parent Baby), and Cas12/Cas13 (Diagnostics/FELUDA).
- [THE STRATEGIC METACOGNITION]: For S&T, UPSC asks 'What is it?' and 'What does it do?'. Do not study the molecular chemical bonds. Study the metaphor: Cas9 = Scissors; Guide RNA = GPS; CRISPR = The Archive.
Concept hooks from this question
👉 Gene as the DNA unit coding for a protein
💡 The insight
A gene is a DNA segment that contains information to make a specific protein, which in turn influences traits.
High-yield for questions on heredity and biotechnology: connects the molecular basis of traits to genetic interventions and helps explain why altering DNA can change protein production. Links to topics on mutation, gene expression and phenotypic effects, enabling answers on genetic modification rationale and outcomes.
📚 Reading List :
- Science , class X (NCERT 2025 ed.) > Chapter 8: Heredity > 8.2.3 How do these Traits get Expressed? > p. 131
- Science , class X (NCERT 2025 ed.) > Chapter 7: How do Organisms Reproduce? > 7.1 DO ORGANISMS CREATE EXACT COPIES OF THEMSEL THEMSELVES? > p. 113
🔗 Anchor: "Is Cas9 protein a molecular "scissors" used for targeted gene editing?"
👉 Genetic modification via insertion of foreign genes (transgenes)
💡 The insight
Genetic modification involves altering an organism's DNA by inserting foreign genes to change traits.
Essential for biotechnology and agriculture segments: clarifies modern definitions of GMOs and grounds discussions of techniques used to create modified crops or organisms. Useful for policy, ethics and technology questions about gene manipulation and its applications.
📚 Reading List :
- Indian Economy, Nitin Singhania .(ed 2nd 2021-22) > Chapter 9: Agriculture > GENETICALLY MODIFIED (GM) CROPS > p. 301
🔗 Anchor: "Is Cas9 protein a molecular "scissors" used for targeted gene editing?"
👉 Chromosomes, germ cells and stability of hereditary DNA
💡 The insight
Chromosomes carry discrete gene units and their segregation during gamete formation preserves species DNA and transmits traits.
Central for inheritance and reproductive biology: explains mechanisms of trait transmission, foundation for understanding how targeted DNA changes in germline or somatic cells affect progeny or individual organisms. Helps answer questions on heredity, Mendelian patterns and implications of genomic edits.
📚 Reading List :
- Science , class X (NCERT 2025 ed.) > Chapter 8: Heredity > separate traits, shape and colour of seeds Figure 8.5 > p. 132
- Science , class X (NCERT 2025 ed.) > Chapter 7: How do Organisms Reproduce? > 7.1 DO ORGANISMS CREATE EXACT COPIES OF THEMSEL THEMSELVES? > p. 113
🔗 Anchor: "Is Cas9 protein a molecular "scissors" used for targeted gene editing?"
👉 Diagnostic methods for infectious diseases
💡 The insight
Laboratory diagnosis (e.g., virus isolation, serological tests) is a primary route to confirm pathogen presence in patients.
High-yield for UPSC because questions often probe laboratory and public-health responses to outbreaks, biosafety requirements, and timelines for definitive diagnosis; links to topics on disease surveillance, public health infrastructure, and technology for detection.
📚 Reading List :
- Environment and Ecology, Majid Hussain (Access publishing 3rd ed.) > Chapter 8: Natural Hazards and Disaster Management > Dengue and Chikungunya > p. 79
- Science ,Class VIII . NCERT(Revised ed 2025) > Chapter 3: Health: The Ultimate Treasure > Snapshots > p. 42
🔗 Anchor: "Is Cas9 protein used as a biosensor for accurate detection of pathogens in patie..."
👉 Pathogens and modes of transmission
💡 The insight
Pathogens enter and spread via routes such as airborne droplets, direct contact, and contaminated food or water, which determine testing strategies and control measures.
Core for epidemiology and health policy questions; mastering transmission modes helps in analyzing containment strategies, vaccination priorities, and prevention measures in public health scenarios.
📚 Reading List :
- Science ,Class VIII . NCERT(Revised ed 2025) > Chapter 3: Health: The Ultimate Treasure > 3.4.1 How are communicable diseases caused and spread? > p. 32
- Science ,Class VIII . NCERT(Revised ed 2025) > Chapter 3: Health: The Ultimate Treasure > Snapshots > p. 42
🔗 Anchor: "Is Cas9 protein used as a biosensor for accurate detection of pathogens in patie..."
👉 Vaccines and immune memory
💡 The insight
Vaccines use weakened/dead pathogens or parts to train the immune system, and prior exposure leads to stronger subsequent immune responses.
Important for questions on immunization policy, vaccine technologies, and population immunity; connects immunology to preventive health and program implementation topics in UPSC mains and ethics-case studies.
📚 Reading List :
- Science ,Class VIII . NCERT(Revised ed 2025) > Chapter 3: Health: The Ultimate Treasure > Chapter 3 — Health: The Ultimate Treasure 45 > p. 45
- Science ,Class VIII . NCERT(Revised ed 2025) > Chapter 3: Health: The Ultimate Treasure > Ability of the body to fight diseases > p. 37
- Science ,Class VIII . NCERT(Revised ed 2025) > Chapter 3: Health: The Ultimate Treasure > Snapshots > p. 42
🔗 Anchor: "Is Cas9 protein used as a biosensor for accurate detection of pathogens in patie..."
👉 Transgenic modification for pest resistance
💡 The insight
Plants can acquire pest-resistance through insertion of foreign genes via genetic modification.
High-yield for questions on GM crops, biotechnology policy, and biosafety; connects biotechnology with agriculture and environmental implications and enables analyses of pros/cons of transgenic crops in governance and regulation.
📚 Reading List :
- Indian Economy, Nitin Singhania .(ed 2nd 2021-22) > Chapter 9: Agriculture > GENETICALLY MODIFIED (GM) CROPS > p. 301
- Environment and Ecology, Majid Hussain (Access publishing 3rd ed.) > Chapter 12: Major Crops and Cropping Patterns in India > Biotic: Living > p. 111
🔗 Anchor: "Is Cas9 a gene that makes plants pest-resistant?"
Option B (Biosensor) was a prophecy. While Cas9 is the 'Scissor' for editing, its cousins Cas12 and Cas13 are now used as 'Biosensors' for detecting pathogens (e.g., the FELUDA test for COVID-19). The wrong option of today is the right question of tomorrow.
Linguistic Precision Hack: The question asks what 'Cas9 protein' is. Option C says 'A gene'. A protein is the *product* of a gene, not the gene itself. Option D says 'Herbicidal substance'—usually chemicals. Option A uses the specific, famous metaphor 'Molecular Scissors' which is the standard definition for nucleases in biology.
Link this to GS-4 (Ethics) and GS-3 (Security). Gene editing leads to 'Designer Babies' (He Jiankui case) raising ethical storms. It also links to 'Dual Use' technologies where bio-tools could be used to create bioweapons.