Q.(a)
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🔒 Start your 14-day free trial to unlock the full solution →Part (a)Concept understanding — Biotechnology Core Concepts
Biotechnology Core Concepts — A First Look
You already know biotechnology better than you think. When you eat yoghurt, that's biotechnology at work. When bread rises, that's biotechnology. When your grandmother used curd to ferment buttermilk, she was practising an ancient form of it. The core idea is simple: using living organisms (or parts of them) to make or modify products for human benefit.
The NCERT textbook defines biotechnology as "the use of living systems and organisms to develop or make useful products." That's the formal version of what you just read.
The Two Big Ideas That Hold Everything Together
Biotechnology rests on two fundamental capabilities that nature gave us, and that scientists learned to harness:
1. Genetic Engineering — the ability to change an organism's DNA directly. Think of it as editing the instruction manual of a living thing. Instead of waiting for nature to produce a trait through slow breeding, scientists can now take a specific gene from one organism and put it into another. A bacterium can be made to produce human insulin because the human insulin gene has been inserted into it.
2. Maintenance of Sterile Conditions — the ability to grow large numbers of cells or microorganisms in a controlled, contamination-free environment. This is called aseptic technique. Without it, the wrong microbes would spoil the process, and you'd get garbage instead of medicine.
These two — genetic engineering and sterile maintenance — are the twin pillars of modern biotechnology. The NCERT explicitly states that biotechnology deals with techniques of using live organisms or enzymes from organisms to produce products useful to humans. The modern era of biotechnology began when we could manipulate DNA directly.
Why This Matters in Everyday Life
You don't need a lab coat to see biotechnology's impact. Consider these examples:
- Medicine: Insulin for diabetes, vaccines, and gene therapy all come from biotechnology. Before genetic engineering, insulin was extracted from the pancreases of pigs and cows — expensive and sometimes caused allergic reactions. Now, bacteria make human insulin for us.
- Agriculture: Crops that resist pests or tolerate drought. Bt cotton, for instance, has a bacterial gene that makes it produce a protein toxic to certain insects, reducing the need for chemical pesticides.
- Environment: Microbes engineered to clean up oil spills or break down plastic waste.
- Food: Cheese, beer, wine, and even the citric acid in your soft drinks are products of microbial biotechnology.
The NCERT classifies biotechnology into two eras: Traditional biotechnology (fermentation, breeding) which humans have used for thousands of years, and Modern biotechnology (genetic engineering, cell culture) which began in the 1970s with the discovery of tools to cut and join DNA.
The Core Tools (What Makes It Possible)
Modern biotechnology relies on a few essential techniques. You don't need to memorise details, but understand what each does:
- Recombinant DNA technology: Cutting a gene from one organism and pasting it into another. This is how we make human insulin in bacteria.
- Gene cloning: Making many identical copies of a gene. If you have one copy of a useful gene, you can make millions.
- Tissue culture: Growing plant or animal cells in a lab dish. A whole plant can be regenerated from a single cell.
- Fermentation technology: Using microbes in large tanks (bioreactors) to produce substances like antibiotics, enzymes, or alcohol.
A Common Misunderstanding to Avoid …
Part (b)Concept understanding — Biology Disease Control
Biology Disease Control — A First Look
Think of your body as a city. Every day, germs (bacteria, viruses, fungi, parasites) try to enter — through the air you breathe, the food you eat, a cut on your skin. Most of the time, your body's defence systems stop them before you even notice. That's immunity, your natural security force.
But sometimes the invaders break through. You get a fever, a cough, an infection. Now you need disease control — the set of actions that stop the illness from spreading and help you recover.
What exactly is disease control?
In biology, disease control means reducing the incidence (new cases), prevalence (total cases), or transmission of a disease. It's not about wiping out every germ — that's impossible. It's about keeping the disease at a level where it no longer threatens public health.
The NCERT textbook divides disease control into two broad approaches:
1. Preventive measures — stopping the disease before it starts
These are actions taken by individuals, communities, and governments to block the entry of pathogens.
- Vaccination — training your immune system to recognise a germ before it attacks. This is the single most powerful tool in disease control.
- Sanitation and hygiene — clean drinking water, proper sewage disposal, handwashing. Many diseases (cholera, typhoid, hepatitis A) spread through contaminated water or food.
- Vector control — killing or avoiding the organisms that carry disease. Mosquito nets, insect repellents, draining stagnant water — these control malaria, dengue, chikungunya.
- Quarantine and isolation — separating sick people from healthy ones during outbreaks. You saw this during COVID-19.
Prevention is always better than cure. Once a disease spreads in a population, controlling it becomes exponentially harder and more expensive. That's why governments invest heavily in vaccination drives and public sanitation.
2. Curative measures — treating the disease once it occurs
Even with the best prevention, some people will fall ill. Curative measures aim to:
- Reduce the severity of the illness (e.g., antibiotics for bacterial infections, antiviral drugs for flu)
- Shorten the duration of the illness
- Prevent complications and death
- Stop the patient from infecting others
The key point: treatment alone cannot control a disease in a population. If you only treat sick people without preventing new infections, the disease keeps circulating.
Why does disease control matter for society?
A single outbreak can paralyse a city. Schools close, hospitals overflow, businesses shut down. The economic cost is enormous. That's why disease control is not just a medical issue — it's a public health issue.
The NCERT textbook emphasises that disease control requires community participation. No matter how good the doctors or vaccines are, if people refuse to vaccinate their children or ignore hygiene, the disease will keep spreading. …
Part (a)
(i) Two core principles/techniques of biotechnology:
- Genetic engineering - techniques to alter the chemistry of genetic material (DNA/RNA) and introduce it into a host to change its phenotype (making recombinant DNA).
- Maintenance of a sterile (contamination-free) environment in chemical/bioprocess engineering, so that only the desired microbe or eukaryotic cell is grown in large amounts to make products such as antibiotics, enzymes and vaccines. (ii) Three key tools of recombinant DNA technology:
- Restriction enzymes - molecular scissors that cut DNA at specific palindromic sequences, often giving sticky ends.
- Cloning vector - a plasmid/phage DNA (e.g. pBR322) that carries the foreign DNA into a host and replicates, with an origin of replication and selectable markers. …
Part (a): Biotechnology is built on (i) genetic engineering and (ii) maintaining sterile bioprocess conditions; three key rDNA tools are restriction enzymes, cloning vectors and DNA ligase. Part (b): Conventional diagnosis (symptoms + biochemical tests) detects disease late and needs high pathogen loads; biotechnology provides PCR, ELISA and gene probes for early, sensitive detection.
Part (a)
(i) Two basic principles/core techniques of biotechnology.
- Genetic engineering: a set of techniques to alter the chemistry of genetic material (DNA and RNA), to introduce these into host organisms and thus change their phenotype - i.e. constructing and transferring recombinant DNA.
- Maintenance of a sterile (microbe-free) environment in bioprocess/chemical engineering: this enables the growth of only the desired microbe or eukaryotic cell in large quantities to manufacture biotechnological products such as antibiotics, enzymes and vaccines.
(ii) Three key tools of recombinant DNA technology.
- Restriction enzymes (restriction endonucleases) act as molecular scissors, recognising specific palindromic sequences and cutting the DNA, often leaving single-stranded 'sticky ends'.
- Cloning vectors such as the plasmid pBR322 carry the foreign DNA into the host cell and replicate there; they have an origin of replication (ori), selectable markers and recognition sites.
- DNA ligase acts as molecular glue, sealing the foreign DNA into the vector by forming phosphodiester bonds. …
Showing the 12 most recent of 59 on this concept.
- CBSE 2026Set 57/3/11 markMCQQ.Match Column I with Column II and select the correct option : Column I a. Primers b. Insertional inactivation c. Bioreactor d. Downstream processing Column II i. β-galactosidase ii. To separate and purify products iii. Chemically synthesized oligonucleotides iv. Large scale production of specific product of activity of microbes Options : (A) a-iii, b-i, c-iv, d-ii (B) a-iii, b-i, c-ii, d-iv (C) a-i, b-iii, c-iv, d-ii (D) a-i, b-iv, c-ii, d-iii
›Reveal solutionSolution
Primers are chemically synthesized oligonucleotides; insertional inactivation uses β-galactosidase; bioreactors enable large-scale microbial production; downstream processing separates and purifies products.
The question tests your understanding of four fundamental tools and processes in biotechnology, each playing a distinct role in genetic engineering and industrial production. Let's work through what each term means and why it matches its partner.
Primers are short stretches of nucleotides—typically 10 to 20 bases long—that are chemically synthesized in the laboratory. They are oligonucleotides, meaning "few nucleotides." In PCR (polymerase chain reaction), primers bind to specific sequences on the DNA template and provide the starting point for DNA polymerase to begin synthesis. Without primers, the enzyme cannot initiate replication. The NCERT textbook explicitly describes primers as chemically synthesized oligonucleotides used in amplification techniques. So a matches iii.
Insertional inactivation is a clever selection technique used to identify recombinant DNA. The principle relies on disrupting a functional gene when foreign DNA is inserted into a plasmid vector. The classic example involves the lacZ gene, which codes for the enzyme β-galactosidase. When a foreign DNA fragment is successfully inserted into the cloning site within lacZ, the gene is inactivated—the enzyme is no longer produced. Colonies containing recombinant plasmids remain white when grown on medium with a chromogenic substrate (like X-gal), while non-recombinant colonies turn blue because their intact β-galactosidase cleaves the substrate. This visual distinction makes screening straightforward. Thus b matches i.
NoteThe blue-white screening method is one of the most widely used techniques in molecular cloning labs because it provides immediate visual confirmation of successful insertion.
Bioreactors are large vessels designed for the controlled, large-scale cultivation of microorganisms, plant cells, or animal cells. They maintain optimal conditions—temperature, pH, oxygen supply, nutrient availability—to maximize the production of desired products like enzymes, antibiotics, vaccines, or recombinant proteins. The NCERT textbook describes bioreactors as systems that provide the ideal environment for growing cultures in volumes ranging from 100 to 1000 liters or more. The entire purpose is large-scale production of a specific product through microbial or cellular activity. Therefore c matches iv. …
- CBSE 2026Set ANNUAL1 markMCQQ.Which is not a step of PCR cycle?(a) Denaturation(b) Primers Annealing(c) Extension of primers(d) Identification of DNA with genes
›Reveal solutionSolution
A PCR cycle has three steps: denaturation, annealing and extension; identifying DNA is not one of them.
The Polymerase Chain Reaction (PCR) amplifies a specific DNA segment through repeated cycles, each with three steps:
- Denaturation: heating (about 94-95 C) separates the double-stranded DNA into single strands.
- Annealing: cooling allows two primers to bind (anneal) to their complementary sequences flanking the target. …
- CBSE 2026Set ANNUAL1 markQ.Fill in the blank: Virus infected cells secrete proteins are called ______.
›Reveal solutionSolution
Proteins secreted by virus-infected cells are called interferons.
When a cell is infected by a virus, it secretes a group of protective proteins called interferons. These interferons diffuse to the surrounding, still-healthy cells and make them resistant to viral infection, thereby limiting the spread o …
- CBSE 2026Set ANNUAL1 markQ.Write answer in one word/sentence: Which type of charge found on DNA fragments?
›Reveal solutionSolution
DNA fragments carry a negative charge because of their phosphate backbone.
The backbone of a DNA molecule is made of alternating sugar and phosphate groups, and the phosphate groups carry negatively charged oxygen atoms. As a result, DNA fragments are negatively charged. This is the basis of gel electrophoresis: when an electric field is applied, the negati …
- CBSE 2026Set ANNUAL1 markMCQQ.Haemozoin is released as a result of –(a) Rupture of liver cells(b) Rupture of red blood cells(c) Multiplication of sporozoites(d) Replication in macrophages
›Reveal solutionSolution
Haemozoin, the toxic malarial pigment, is liberated when parasitised red blood cells rupture, causing the characteristic recurring chills and fever.
When a female Anopheles mosquito bites, Plasmodium sporozoites enter the human liver, multiply, and then invade red blood cells. Inside the RBCs the parasite digests haemoglobin and multiplies. When the infected RBCs burst to release the next generation of parasites, they also release a to …
- CBSE 2026Set ANNUAL1 markMCQQ.The enzyme required for isolating DNA from fungi is –(a) Cellulase(b) Chitinase(c) Lysozyme(d) Endonuclease
›Reveal solutionSolution
Fungal cell walls are made of chitin, so the enzyme chitinase is used to break them open and release the DNA.
The first step in isolating genetic material (DNA) is to break open the cell and its wall so that the DNA is released along with other macromolecules. Because different organisms have different cell-wall chemistry, different enzymes are used:
- Bacteria → lysozyme (digests peptidoglycan) …
- CBSE 2026Set ANNUAL1 markMCQQ.Assertion : Ligase enzyme is used to join a foreign gene with a cloning vector. Reason : Ligase forms phosphodiester bonds between complementary base pairs.(a) If both Assertion and Reason are true and Reason is a correct explanation of the Assertion.(b) If both Assertion and Reason are true but Reason is not a correct explanation of the Assertion.(c) If Assertion is true but Reason is false.(d) If both Assertion and Reason are false.
›Reveal solutionSolution
Assertion (ligase joins gene to vector) is true, but the Reason is worded wrongly — ligase makes phosphodiester bonds in the backbone between adjacent nucleotides, not between base pairs — so the correct choice is (C).
Evaluating the Assertion: DNA ligase is indeed the enzyme that joins a foreign DNA fragment (gene) to a cloning vector, sealing them into a recombinant DNA molecule. So the Assertion is TRUE.
…
- CBSE 2026Set ANNUAL1 markQ.Give reason for moving DNA fragments towards the anode in gel electrophoresis.
›Reveal solutionSolution
DNA is negatively charged because of its phosphate backbone, so it migrates towards the positive electrode (anode) during gel electrophoresis.
In gel electrophoresis, DNA fragments are separated according to size by forcing them through an agarose gel in an electric field. Every nucleotide of DNA carries a negatively charged phosphate group in its sugar-phosphate backbone, so the whole DNA molecule is negatively charged.
…
- CBSE 2026Set ANNUAL1 markMCQQ.The enzyme Taq polymerase used in PCR has been isolated from the bacterium :(a) Agrobacterium tumefaciens(b) Thermus aquaticus(c) Streptomyces albus(d) Escherichia coli
›Reveal solutionSolution
Taq polymerase, the thermostable DNA polymerase used in PCR, comes from the hot-spring bacterium Thermus aquaticus, so (b) is correct.
In the CBSE/NCERT Biotechnology: Principles and Processes chapter, PCR (Polymerase Chain Reaction) heats DNA to ~94°C to denature it. An ordinary DNA polymerase would be destroyed at that temperature, so PCR uses a thermostable polymerase that survives repeated high-temperature cycles. This enzyme, Taq polymerase, is isolated from *Thermus aquaticus …
- CBSE 2026Set ANNUAL1 markQ._________ test is performed to confirm typhoid.
›Reveal solutionSolution
The blank is the Widal test — the diagnostic test that detects antibodies against Salmonella typhi to confirm typhoid fever.
In the CBSE/NCERT Human Health and Disease chapter, typhoid is caused by Salmonella typhi, spread through contaminated food and water. It is confirmed by the **Widal te …
- CBSE 2025Set A1 markQ.Write True / False: All microbes are not pathogenic.
›Reveal solutionSolution
The statement is True: most microbes are non-pathogenic and many are beneficial to humans.
Microbes (bacteria, fungi, protozoa, viruses, archaea) are extremely diverse, and only a small proportion of them are pathogens capable of causing disease in humans, plants or animals. The overwhelming majority of microbes play beneficial or neutral roles — decomposing organic matter, fixing nitrogen, fermenting food and beverages (curd, bread, alcoholic drinks), pro …
- CBSE 2025Set ANNUAL1 markMCQQ.Match the process in column I with their uses in column II and choose the correct option: Column I \tColumn II A) ELISA \ti) Direct introduction of rDNA B) PCR \tii) Gene amplification C) Biolistic \tiii) Antigen-antibody interaction D) Micro-injection \tiv) Gold coated DNA(a) A(iv), B(iii), C(ii), D(i)(b) A(i), B(ii), C(iii), D(iv)(c) A(ii), B(i), C(iv), D(iii)(d) A(iii), B(ii), C(iv), D(i)
›Reveal solutionSolution
ELISA uses antigen-antibody interaction, PCR amplifies genes, Biolistic uses gold-coated DNA particles, and Micro-injection directly introduces rDNA — matching gives A(iii), B(ii), C(iv), D(i).
Correct matching of each technique with its principle/use:
- A) ELISA (Enzyme-Linked ImmunoSorbent Assay) — based on the specific antigen-antibody interaction (iii); used to detect the presence of an antigen (e.g., a pathogen protein) or antibody (e.g., in disease diagnosis, pregnancy tests) in a sample.
- B) PCR (Polymerase Chain Reaction) — used for gene amplification (ii); makes multiple copies of a gene/DNA segment of interest in vitro, using the enzyme Taq polymerase. …
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