Faqs Biotechnology And Its Applications Class 12 Biology Cbse, Chse

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🧬 FAQs: Biotechnology and its Applications Class 12 Biology CBSE, CHSE

I. Applications in Agriculture (GMOs)

Q1. What are Genetically Modified Organisms (GMOs)?

A. GMOs are organisms (plants, animals, bacteria, or fungi) whose genes have been altered by manipulation (introducing a foreign gene) to possess desired characteristics.

Q2. What is the advantage of Golden Rice?

A. Golden Rice is a transgenic rice variety enriched with Vitamin A (specifically β-carotene, the precursor to Vitamin A). Its creation aimed at combating Vitamin A deficiency in populations relying heavily on rice as a staple food.

Q3. How does the Bt toxin protein kill insects but not the Bacillus thuringiensis bacterium or humans?

The Bt toxin is produced by the bacterium as an inactive protoxin (Cry protein).

It only becomes an active toxin when the insect ingests it, due to the alkaline pH in the insect's gut, which solubilizes the crystal.

The active toxin binds to the midgut epithelial cells, causing pores, cell swelling, lysis, and ultimately the insect's death.

Neither the bacterium nor the human gut (which has an acidic pH) can activate the protoxin, so it is safe for them.

Q4. Explain the principle of RNA interference (RNAi) in pest control.

A. RNAi is a cellular defense mechanism that works by silencing a specific mRNA using a complementary double-stranded RNA (dsRNA) molecule.

In the case of nematode resistance (Meloidogyne incognita in tobacco), nematode-specific genes are introduced into the plant.

These genes produce dsRNA, which binds to the nematode's mRNA.

This binding prevents the translation of the nematode's mRNA, leading to the paralysis and death of the parasite.

II. Applications in Medicine (Therapeutics & Diagnostics)

Q5. How is genetically engineered human insulin (Humulin) different from the proinsulin initially synthesized in mammals?

A. Proinsulin (synthesized naturally) is the inactive precursor and contains an extra stretch called the C-peptide.

Mature insulin (Humulin) lacks this C-peptide.

In recombinant DNA technology (used by Eli Lilly in 1983), the A and B peptide chains are produced separately in E. coli and then chemically joined in vitro by disulphide bridges to form mature, functional insulin, omitting the C-peptide.

Q6. What are the two methods for correcting ADA (Adenosine Deaminase) deficiency? Why is gene therapy a superior option?

Enzyme Replacement Therapy: Periodic injection of the functional ADA enzyme.

Bone Marrow Transplantation: Transplantation of bone marrow cells.

Both methods are not a permanent cure because the administered cells/enzyme are mortal (short-lived) and require regular treatment.

Gene therapy (introducing a functional ADA cDNA gene into early embryonic cells) can be a permanent cure because the cells at this stage are dividing rapidly and are not fully differentiated.

Q7. What is the principle and application of ELISA and PCR in molecular diagnosis?

ELISA (Enzyme-Linked Immunosorbent Assay): Based on the antigen-antibody interaction. It detects the presence of the pathogen's antigens or the antibodies produced against the pathogen. (e.g., used for early diagnosis of AIDS).

PCR (Polymerase Chain Reaction): Used for amplification of nucleic acids (DNA/RNA). It can detect pathogens (e.g., HIV, viruses) or genetic mutations (e.g., in cancer) when they are present in very low concentrations, much earlier than conventional methods.

III. Transgenic Animals and Ethics

Q8. Name the first transgenic cow and mention the special quality of its milk.

A. The first transgenic cow was Rosie (1997).

It produced human protein-enriched milk containing human alpha-lactalbumin (2.4 grams per litre).

This milk was nutritionally more balanced for human babies than natural cow milk.

Q9. List the five main purposes for the creation of transgenic animals.

To study Normal Physiology and Development (e.g., studying growth factors).

To study Disease (creating models for human diseases like Alzheimer's or Cystic Fibrosis).

To produce Biological Products (e.g., alpha-1-antitrypsin for emphysema).

Vaccine Safety Testing (e.g., testing the Polio vaccine).

Chemical Safety/Toxicity Testing (using more sensitive transgenic animals).

Q10. What is the role of the Genetic Engineering Appraisal Committee (GEAC)?

A. The GEAC is an Indian governmental organization responsible for:

Making decisions regarding the validity of GM (Genetically Modified) research.

Assessing the safety of introducing GM organisms (GMOs) for public use and the environment, including experimental field trials.

Q11. Define Biopiracy. Give one example.

A. Biopiracy is the unauthorized use of bio-resources and associated traditional knowledge by multinational companies and other organizations without proper authorization from the concerned country or people (especially the traditional knowledge holders) and without compensatory payment.

Example: Patenting of the traditional Indian varieties of Basmati rice or the properties of Neem/Turmeric.

Long Question FAQs: Biotechnology and its Applications

Q1. Explain the process of producing genetically engineered human insulin (Humulin) using recombinant DNA technology.

A. The production of Humulin by the American company Eli Lilly in 1983 was a landmark achievement. It involves the following steps:

Chemical Synthesis of Genes: Human insulin consists of two polypeptide chains: Chain A (21 amino acids) and Chain B (30 amino acids), linked by disulfide bonds. Unlike natural insulin production (which involves a proinsulin precursor), the DNA sequences corresponding to the mature A and B chains are chemically synthesized in the lab.

Insertion into Vector: The DNA sequences for Chain A and Chain B are introduced separately into the plasmids of two different strains of Escherichia coli (E coli) bacteria using restriction enzymes and DNA ligase. The plasmid acts as the vector to carry the gene.

Transformation and Cloning: The recombinant plasmids are introduced into the respective (E coli ) host cells (a process called transformation). The bacteria are then grown in large fermenters (bioreactors) to clone the genes and produce the corresponding A and B polypeptide chains.

Extraction and Purification: The polypeptide chains (A and B) are synthesized and secreted into the bacterial culture medium. They are then extracted and purified from the (E. coli) cultures.

Assembly of Mature Insulin: The extracted Chain A and Chain B are chemically linked in vitro (outside the cell) using disulphide bridges to create the fully functional and active Humulin (human insulin).

Q2. Describe the treatment for Adenosine Deaminase (ADA) deficiency, including the advantages of gene therapy over other methods.

A. ADA deficiency causes Severe Combined Immunodeficiency (SCID) due to the loss of the ADA enzyme, which is crucial for T-lymphocyte and B-lymphocyte function.

Treatment Methods:

Enzyme Replacement Therapy (ERT):

The patient is given a periodic infusion of the PEG-ADA enzyme (modified ADA) to compensate for the deficiency.

Disadvantage: It is not a permanent cure and requires lifelong injections.

Bone Marrow Transplantation:

Hematopoietic stem cells are transplanted, ideally from an HLA-matched sibling donor.

Disadvantage: It requires a suitable, matched donor and carries risks of rejection or infection.

Gene Therapy (The Permanent Cure):

Procedure (First clinical trial in 1990):

Isolation of Lymphocytes: Lymphocytes are isolated from the patient's blood and grown in culture.

Gene Introduction: A functional ADA cDNA (complementary DNA) is introduced into the lymphocytes using a retroviral vector.

Infusion: The engineered, functional lymphocytes are returned to the patient.

Disadvantage: Since lymphocytes are mortal (have a limited life span), this is still not a permanent cure and requires periodic infusions.

Permanent Solution: If the gene isolated from the bone marrow cells is introduced into the cells at a very early embryonic stage, it can be a permanent and complete cure for the disease.

Q3. Explain the mechanism of action of Bt toxin against insect pests and justify why it does not harm humans or the Bacillus thuringiensis bacterium.

A. The Bt toxin is a biological insecticide derived from the bacterium Bacillus thuringiensis (Bt).

Mechanism of Action against Insects:

Protoxin Stage: The bacterium produces the toxin in an inactive, crystalline protoxin form (Cry protein), which is stored within its body.

Ingestion and Activation: When an insect, such as the cotton bollworm, ingests the crystal protein along with the plant tissue, the inactive protoxin reaches the insect's midgut.

Alkaline pH Effect: The highly alkaline pH of the insect's gut (unlike the acidic human gut) solubilizes the crystal and converts the inactive protoxin into the active toxin.

Binding and Lysis: The activated toxin binds to the surface of the midgut epithelial cells. This creates pores in the cell membrane, causing the cells to swell and lyse (burst), leading to the death of the insect larva.

Justification for Safety:

Safety to B thuringiensis: The bacterium is protected because the toxin is synthesized and stored in the inactive protoxin form, which does not bind to its own cells.

Safety to Humans: The human stomach is highly acidic. This acidic environment prevents the activation (solubilization and cleavage) of the protoxin, so the toxin remains inactive and poses no threat.

Q4. Describe the five main applications of transgenic animals, focusing on how they benefit humans in producing biological products and testing safety.

A. Transgenic animals are those whose DNA has been manipulated to possess and express an extra, foreign gene.

Application Category	Description and Example	Benefit to Humans
1. Normal Physiology	Animals are engineered to study the role of specific genes in normal body functions (e.g., studying growth factors).	Helps in understanding complex gene regulation and its effect on development.
2. Study of Disease	They serve as disease models (e.g., for cancer, cystic fibrosis, Alzheimer's). Genes causing human diseases are introduced.	Allows researchers to study disease progression and test new drugs/treatments before human trials.
3. Biological Products	They are used as biological factories to produce useful therapeutic proteins (Molecular Farming).	Production of rare and expensive human proteins easily and cheaply. Example: Rosie (first transgenic cow) produced milk with human α-lactalbumin, nutritionally superior to natural cow milk.
4. Vaccine Safety Testing	Transgenic animals (e.g., mice) are developed to be sensitive to the disease, allowing vaccine safety to be tested.	Ensures the safety and efficacy of vaccines (e.g., Polio vaccine safety was tested on transgenic mice).
5. Chemical Safety Testing	Transgenic animals (made more sensitive to toxins) are used to test the safety or toxicity of chemicals.	Provides reliable data on the toxicity of drugs and chemicals, reducing the potential risk to humans.

Q5. What is Biopiracy? Discuss the ethical issues related to the use of genetically modified organisms (GMOs).

Biopiracy:

Definition: It is the term used to refer to the use of bio-resources (plants, animals, microbes) and associated traditional knowledge belonging to indigenous people/countries by multinational companies and other organizations without proper authorisation and without compensatory payment.

Examples: The patenting of the properties of Indian Basmati rice varieties, Neem, and Turmeric by foreign entities without acknowledging or compensating India for its traditional knowledge.

Ethical Issues Related to GMOs:

Environmental Risks:

The potential for GM genes (e.g., herbicide resistance) to spread to wild relatives, creating "superweeds."

The risk of the Bt toxin harming non-target beneficial insects, like pollinating bees.

Possible damage to native biodiversity due to genetic pollution.

Health Risks:

The possibility of new toxins or allergens being introduced into food through genetic modification, affecting human health.

The fear of antibiotic resistance genes (often used as selectable markers in cloning) spreading to human pathogenic bacteria.

Ethical/Moral Concerns:

Manipulation of living organisms (creating novel life forms) is seen by some as crossing natural limits, raising moral objections.

Regulatory Oversight (GEAC):

The Genetic Engineering Appraisal Committee (GEAC) in India was set up to address these issues by reviewing the validity of GM research and the safety of introducing GM organisms for public use.

Here are 5 additional long-question FAQs (5-mark level) from the chapter Biotechnology and its Applications, designed to cover detailed explanatory topics.

Q6. Describe the principle, procedure, and application of Polymerase Chain Reaction (PCR) and Enzyme-Linked Immunosorbent Assay (ELISA) for molecular diagnosis.

A. Molecular diagnosis techniques are crucial for the early detection of pathogens and genetic disorders when symptoms are not yet visible, which is often impossible with conventional methods (serum, urine analysis).

Technique	Principle	Procedure (in Brief)	Key Applications
PCR (Polymerase Chain Reaction)	Based on the amplification of a target nucleic acid (DNA or RNA) sequence. It creates millions of copies of a gene of interest.	1. Denaturation (Heating to separate DNA strands). 2. Annealing (Cooling to allow primers to bind). 3. Extension (DNA polymerase synthesizes new strands). This cycle is repeated =30 - 40 times.	1. Early detection of pathogens (e.g., HIV, H1N1, TB) when they are present in very minute quantities. 2. Detecting gene mutations in suspected cancer patients. 3. DNA fingerprinting (forensics).
ELISA (Enzyme-Linked Immunosorbent Assay)	Based on the antigen-antibody interaction. It detects either the presence of antigens (pathogen proteins) or the antibodies synthesized by the host against the pathogen.	1. Coating a microtiter plate with the antigen (or antibody). 2. Adding the patient's sample (serum). 3. Adding an enzyme-linked secondary antibody (conjugate). 4. Adding a substrate, which changes color in the presence of the enzyme.	1. Routine screening for infectious diseases (e.g., AIDS/HIV, Hepatitis B). 2. Quantifying hormones or proteins in serum. 3. Used for rapid, high-throughput screening.

Q7. Give a detailed explanation of how biotechnology has led to the development of pest-resistant plants using the principle of RNA interference (RNAi).

A. RNA interference (RNAi) is a cellular mechanism used by all eukaryotic organisms to defend against pathogens and is utilized in biotechnology to confer pest resistance.

Application: Creating nematode-resistant tobacco plants against the parasite Meloidogyne incognita.

Mechanism (Steps):

Introduction of Specific Genes: DNA containing the sequences that code for both the sense RNA and the anti-sense RNA specific to the nematode's genes is introduced into the host plant (e.g., tobacco) using the vector Agrobacterium tumefaciens.

dsRNA Formation: Inside the host plant's cells, this introduced DNA is transcribed to produce both the sense and anti-sense RNA. These two complementary strands bind to each other to form a double-stranded RNA (dsRNA).

Initiation of RNAi: The dsRNA initiates the process of RNAi. Cellular enzymes recognize the dsRNA and process it into small interfering RNAs (siRNAs).

Gene Silencing: The siRNAs bind to and silence the specific, complementary messenger RNA (mRNA) of the invading nematode.

Pest Death: The silencing of the nematode's specific mRNA prevents the essential proteins from being translated, causing the parasite to starve and die. In effect, the plant is equipped with a defense mechanism that specifically targets and silences the parasite's vital genes.

Q8. Discuss the key ethical and regulatory issues related to the use of GMOs in food and medicine, and explain the concept of Biopiracy with a relevant example.

A. The ethical and social dilemmas surrounding biotechnology necessitate strict regulation and ethical considerations.

Ethical and Regulatory Issues of GMOs:

Safety to Human Health: Concerns about whether GM food products might cause allergic reactions or introduce new toxins into the human diet. Regulatory bodies like GEAC must ensure long-term health safety.

Environmental Impact: Fear of gene flow (cross-pollination) spreading foreign genes (like herbicide resistance) to wild relatives, potentially creating "superweeds." There is also concern about the Bt toxin harming non-target insects (e.g., monarch butterflies).

Economic Impact: The high cost of proprietary GM seeds can increase the debt and dependency of small farmers on multinational corporations.

GEAC (Genetic Engineering Appraisal Committee): This Indian governmental body is statutorily mandated to evaluate the validity of GM research and assess the safety of introducing GM organisms for commercial or public use.

Biopiracy:

Definition: The unauthorized and uncompensated exploitation of bio-resources (genetic material, organisms) and the associated traditional knowledge of a developing country or indigenous community by multinational companies from developed countries.

Example (Basmati Rice): India has hundreds of varieties of Basmati rice, known for its unique aroma and grain length, cultivated through generations of traditional farming. In the 1990s, an American company obtained a patent on a "new" variety of Basmati by simply cross-breeding Indian varieties with semi-dwarf strains and claimed it as an invention, effectively allowing them to market and sell the product globally without paying compensation or royalty to India.

Q9. Justify the production of transgenic animals, detailing their use in studying human diseases and producing valuable biological products (molecular farming).

A. Transgenic animals, which carry and express an extra, foreign gene, are invaluable tools in biomedical research and pharmaceutical production.

I. Studying Human Diseases (Disease Models):

Transgenic animals are specifically designed to carry genes that are known to cause or contribute to human diseases.

By inserting or deleting genes, scientists can create animal models that mimic the pathology of human disorders like cancer, cystic fibrosis, Alzheimer's disease, and rheumatoid arthritis.

These models allow researchers to:

Study the gene regulation and progression of the disease in a living system.

Test new drugs and therapies in a controlled environment before human clinical trials, thereby accelerating drug discovery and ensuring patient safety.

II. Producing Biological Products (Molecular Farming):

Transgenic animals are used as "biological factories" to produce high-value therapeutic proteins that are difficult or expensive to synthesize chemically. This process is called molecular farming.

The human gene for the desired protein is introduced into the animal's genome, often regulated to express the protein in an easily extractable fluid, such as milk.

Example (Rosie, the Transgenic Cow): The first transgenic cow, Rosie (1997), produced milk enriched with human alpha-lactalbumin (2.4 g/L). This milk was nutritionally superior to natural cow milk and a better alternative for human babies.

Other Examples: Production of alpha-1-antitrypsin (to treat emphysema) and various therapeutic antibodies and hormones.

Q10. Differentiate between Enzyme Replacement Therapy (ERT) and Gene Therapy as treatment options for Adenosine Deaminase (ADA) deficiency, clearly stating which offers the potential for a permanent cure and why.

A. ADA deficiency is a genetic disorder leading to severe combined immunodeficiency (SCID).

Feature	Enzyme Replacement Therapy (ERT)	Gene Therapy
Nature of Treatment	Biochemical/Pharmaceutical. Involves injecting the missing enzyme directly.	Genetic/Cellular. Involves replacing the defective gene with a functional one.
Mechanism	The patient is injected with the functional, modified ADA enzyme (PEG-ADA).	A functional ADA cDNA is isolated and inserted into the patient's cells (e.g., lymphocytes or stem cells) using a vector (e.g., retrovirus).
Cure Status	Temporary/Palliative. The enzyme has a limited lifespan and needs to be administered periodically (injections).	Potentially Permanent. The new gene is meant to be replicated in the patient's cells, theoretically providing a continuous supply of the enzyme.
Target Cells	The entire body (systemic injection).	Specific target cells (usually lymphocytes or bone marrow hematopoietic stem cells).
Permanent Cure Requirement	Cannot provide a permanent cure.	Can provide a permanent cure only if the functional gene is introduced into the patient's cells (like stem cells) at a very early embryonic stage before the defect causes irreversible damage.

Conclusion on Permanent Cure:

Gene therapy holds the potential for a permanent cure, specifically when the corrected gene is introduced into pluripotent stem cells at an early embryonic stage. At this stage, the gene is incorporated into all developing cells, ensuring the lifelong production of the functional ADA enzyme. Treatment of mature lymphocytes (as done in the 1990 clinical trial) is only periodic, as these cells have a limited life span.