questions with their answers, prepared for Class 12 CHSE Biology students, covering the chapter "Biotechnology and its Applications."
Chapter: Biotechnology and its Applications
Multiple Choice Questions (MCQ)
1. Which of the following is NOT a core technique of modern biotechnology?
a) Genetic engineering
b) Bioprocess engineering
c) Traditional breeding
d) Recombinant DNA technology
Answer: c) Traditional breeding
2. The molecular 'scissors' used in genetic engineering are:
a) DNA ligases
b) Restriction enzymes
c) DNA polymerases
d) Reverse transcriptases
Answer: b) Restriction enzymes
3. Which of the following acts as a cloning vector?
a) Plasmid
b) Ribosome
c) Mitochondrion
d) Nucleus
Answer: a) Plasmid
4. The enzyme used to join the sticky ends of DNA fragments is:
a) DNA polymerase
b) Restriction endonuclease
c) DNA ligase
d) RNA polymerase
Answer: c) DNA ligase
5. What is the correct sequence of steps in Recombinant DNA technology?
I. Insertion of recombinant DNA into host cell
II. Isolation of the genetic material
III. Cutting of DNA at specific locations
IV. Amplification of gene of interest
V. Ligation of DNA fragments
a) II, III, V, I, IV
b) III, II, V, IV, I
c) II, V, III, I, IV
d) IV, II, III, V, I
Answer: a) II, III, V, I, IV
6. The first human hormone produced by recombinant DNA technology was:
a) Thyroxine
b) Insulin
c) Adrenaline
d) Growth hormone
Answer: b) Insulin
7. "Humulin" is a genetically engineered product used to treat:
a) Cancer
b) AIDS
c) Diabetes
d) Haemophilia
Answer: c) Diabetes
8. Gene therapy is primarily used to treat:
a) Infectious diseases
b) Genetic disorders
c) Autoimmune diseases
d) Hormonal deficiencies
Answer: b) Genetic disorders
9. The first clinical gene therapy was given in 1990 to a four-year-old girl for:
a) Cystic Fibrosis
b) Adenosine Deaminase (ADA) deficiency
c) Phenylketonuria (PKU)
d) Sickle Cell Anemia
Answer: b) Adenosine Deaminase (ADA) deficiency
10. Bt toxin is produced by the bacterium:
a) Agrobacterium tumefaciens
b) Escherichia coli
c) Bacillus thuringiensis
d) Rhizobium leguminosarum
Answer: c) Bacillus thuringiensis
11. The Bt toxin protein, when ingested by insects, causes:
a) Production of more digestive enzymes
b) Lysis of gut epithelial cells
c) Resistance to insecticides
d) Increased growth rate
Answer: b) Lysis of gut epithelial cells
12. Which of the following is NOT an advantage of producing transgenic animals?
a) Study of diseases
b) Production of biological products
c) Increased genetic diversity in wild populations
d) Vaccine safety testing
Answer: c) Increased genetic diversity in wild populations
13. The first transgenic cow, "Rosie", produced milk enriched with:
a) Vitamin A
b) Human alpha-lactalbumin
c) Insulin
d) Growth hormone
Answer: b) Human alpha-lactalbumin
14. What is biopiracy?
a) Unauthorized cloning of living organisms
b) Stealing genetic material from laboratories
c) Exploitation of bioresources by multinational companies without proper authorization or compensation to the originating country/people
d) Illegal trade of endangered species
Answer: c) Exploitation of bioresources by multinational companies without proper authorization or compensation to the originating country/people
15. A patent granted for a biological product or process prevents others from:
a) Studying the product/process
b) Using, selling, or importing the product/process without permission
c) Developing new products based on the patented one
d) Publishing research on the patented product/process
Answer: b) Using, selling, or importing the product/process without permission
Short Answer Questions (2-3 marks)
1. Define biotechnology in your own words.
Answer: Biotechnology is the use of living organisms, their parts, or their products to develop or modify products or processes for specific practical purposes, particularly in health, agriculture, and environment.
2. What is genetic engineering? Name two key tools required for it.
Answer: Genetic engineering is the direct manipulation of an organism's genes using biotechnology. It involves altering the genetic makeup by inserting, deleting, or modifying genes. Two key tools are restriction enzymes and cloning vectors (e.g., plasmids).
3. What are restriction enzymes? What is their function in genetic engineering?
Answer: Restriction enzymes (or restriction endonucleases) are enzymes that cut DNA at specific recognition sequences called palindromic sequences. In genetic engineering, they are used to cut the desired gene and the vector DNA, creating compatible "sticky ends" for ligation.
4. What is a cloning vector? Give an example.
Answer: A cloning vector is a DNA molecule (often a plasmid or a virus) that can carry a foreign DNA fragment and replicate it independently within a host cell. It acts as a vehicle to transfer the desired gene. Example: Plasmid (e.g., pBR322), Bacteriophages.
5. What are 'sticky ends' in DNA? Why are they important in Recombinant DNA technology?
Answer: Sticky ends are short, single-stranded overhangs created when a restriction enzyme cuts DNA in a staggered manner. They are important because they are complementary to each other and can form hydrogen bonds with other DNA fragments cut by the same restriction enzyme, facilitating the joining (ligation) of desired gene into the vector.
6. Briefly explain the process of gene amplification using PCR.
Answer: Polymerase Chain Reaction (PCR) is a technique used to make millions of copies of a specific DNA segment in vitro. It involves repeated cycles of:
1. Denaturation: Heating to separate DNA strands.
2. Annealing: Cooling to allow primers to bind to complementary sequences.
3. Extension: DNA polymerase synthesizes new DNA strands using dNTPs. This process allows exponential amplification of the desired gene.
7. How was 'Humulin' produced using biotechnology?
Answer: Humulin (human insulin) was produced by Eli Lilly and Company. They prepared two DNA sequences corresponding to the A and B chains of human insulin. These chains were separately inserted into plasmids of E. coli. The E. coli then produced the A and B chains separately, which were then extracted and combined by creating disulfide bonds to form functional human insulin.
8. What is gene therapy? For which disease was it first successfully used?
Answer: Gene therapy is a technique used to correct a defective gene that is responsible for a disease. It involves introducing a functional gene into a patient's cells to replace a mutated or missing gene. It was first successfully used in 1990 for treating Adenosine Deaminase (ADA) deficiency.
9. What are Genetically Modified Organisms (GMOs)? Give one agricultural application.
Answer: Genetically Modified Organisms (GMOs) are organisms (plants, animals, or microorganisms) whose genetic material (DNA) has been altered in a way that does not occur naturally by mating and/or natural recombination. Agricultural application: Bt cotton (pest resistance), Golden Rice (enhanced nutritional value).
10. Explain how Bt toxin acts as a pest control agent in plants.
Answer: Bt toxin is produced by the bacterium Bacillus thuringiensis. The gene for this toxin (cry gene) is introduced into crop plants (e.g., cotton). When an insect (e.g., bollworm) ingests the plant part, the inactive Bt protoxin in the plant is activated by the alkaline pH of the insect gut. The activated toxin binds to the epithelial cells of the midgut, creating pores that cause cell swelling and lysis, eventually leading to the death of the insect.
11. List two benefits of producing transgenic animals.
Answer:
* Study of Diseases: Transgenic animals (e.g., mice) serve as models for studying human diseases like cancer, cystic fibrosis, Alzheimer's, enabling the development of new treatments.
* Production of Biological Products: They can be used to produce valuable biological products (e.g., human alpha-lactalbumin from transgenic cow "Rosie", anti-thrombin III from transgenic goats).
* Vaccine Safety Testing: Used to test the safety of vaccines before human trials.
* Chemical Safety Testing: Used to test the toxicity of chemicals.
12. What is RNA interference (RNAi)? How is it used in pest resistance?
Answer: RNA interference (RNAi) is a cellular mechanism that inhibits gene expression by neutralizing targeted mRNA molecules. In pest resistance (e.g., against nematodes in tobacco plants), specific RNA sequences are introduced into the plant. These produce double-stranded RNA (dsRNA) that is complementary to the nematode's specific mRNA. When the nematode feeds on the plant, this dsRNA silences the nematode's essential gene (via RNAi), leading to the pest's death.
13. What is a patent in the context of biotechnology?
Answer: A patent is a set of exclusive rights granted by a sovereign state to an inventor or assignee for a limited period in exchange for detailed public disclosure of an invention. In biotechnology, patents are granted for biotechnological inventions, processes, or products (e.g., a specific gene sequence, a transgenic organism, a method for producing a recombinant protein).
14. Mention one ethical concern related to the use of genetically modified food.
Answer: One ethical concern is the potential for allergic reactions in humans due to new proteins produced in GMOs, or the transfer of antibiotic resistance genes from GMOs to gut bacteria. Another concern is the potential impact on biodiversity if GMOs cross-pollinate with wild relatives.
15. What are 'bioreactors' in industrial biotechnology?
Answer: Bioreactors are large vessels (typically 100-1000 litres capacity) where biological processes are carried out under controlled conditions to produce desired products. They provide optimal growth conditions (temperature, pH, nutrients, oxygen) for microbial or plant/animal cell cultures to produce enzymes, proteins, antibiotics, etc., on a large scale.
Long Answer Questions (5-6 marks)
1. Describe the key steps involved in Recombinant DNA Technology. How has this technology revolutionized the field of medicine with respect to human insulin production and gene therapy?
Answer:
Key Steps in Recombinant DNA Technology (Genetic Engineering): Recombinant DNA Technology (rDNA technology) involves the creation of genetically modified organisms by inserting desired foreign DNA into a host organism. The core steps are:
Isolation of the Genetic Material (DNA):
The first step is to isolate pure DNA from the donor organism. This involves breaking open the cells using enzymes (e.g., lysozyme for bacteria, cellulase for plants, chitinase for fungi) and then treating with proteases and RNase to remove proteins and RNA. DNA is finally precipitated with chilled ethanol.
Cutting of DNA at Specific Locations:
Both the isolated desired DNA and the cloning vector DNA are cut at specific recognition sites using restriction enzymes (restriction endonucleases). These enzymes act as molecular scissors, creating compatible "sticky ends" or blunt ends. The same restriction enzyme is used for both the donor DNA and the vector to ensure compatibility.
Amplification of Gene of Interest (Optional but common):
If the desired gene is in small quantity, Polymerase Chain Reaction (PCR) is used to amplify multiple copies of the gene. PCR rapidly synthesizes millions of copies of the specific DNA segment.
Ligation of DNA Fragments (Joining):
The cut foreign DNA fragment (gene of interest) and the cut vector DNA are mixed together. An enzyme called DNA ligase is used to join the sticky ends (or blunt ends) of the foreign DNA and vector DNA, forming a recombinant DNA (rDNA) molecule.
Insertion of Recombinant DNA into Host Cell:
The recombinant DNA is then introduced into a suitable host organism (e.g., E. coli, yeast, plant cell) through various methods like transformation (for bacteria), microinjection, or biolistics (gene gun). The host cells that take up the rDNA are called transformed cells.
Selection and Screening of Transformed Host Cells:
Transformed cells need to be identified from non-transformed cells. This often involves using selectable markers (e.g., antibiotic resistance genes) present on the vector, allowing only the transformed cells to grow on a selective medium. Further screening methods are used to identify cells containing the desired gene and expressing the desired protein.
Obtaining the Foreign Gene Product (Expression):
The host cell now contains the foreign gene. Under optimal conditions (e.g., using a bioreactor), the host expresses the inserted gene to produce the desired protein product. This involves transcription of the gene into mRNA and translation of mRNA into protein.
Downstream Processing:
After the biosynthesis, the desired protein is separated, purified, and formulated for market.
Revolutionizing Medicine:
Human Insulin Production:
Historically, insulin for diabetic patients was extracted from the pancreas of slaughtered cattle and pigs, which sometimes caused allergic reactions.
Using rDNA technology, the genes for human insulin A and B chains were synthesized chemically. These chains were then separately inserted into plasmids of E. coli bacteria.
The E. coli strains were grown in bioreactors, producing the A and B chains separately. These chains were then extracted, purified, and joined together by disulfide bonds to create functional human insulin ("Humulin").
This biotechnological production ensures a constant, safe, and readily available supply of human insulin, free from animal impurities, significantly improving the lives of diabetic patients.
Gene Therapy:
Gene therapy is a groundbreaking approach to treat genetic disorders by replacing a defective gene with a functional one.
First Clinical Application: In 1990, the first gene therapy was performed on a 4-year-old girl with Adenosine Deaminase (ADA) deficiency, a severe combined immunodeficiency (SCID) disorder. ADA enzyme is crucial for immune system function.
Process for ADA deficiency: Lymphocytes from the patient's blood were isolated and grown in culture. A functional ADA cDNA (complementary DNA) was introduced into these lymphocytes using a retroviral vector. The genetically engineered lymphocytes were then returned to the patient's body.
Impact: While not a permanent cure (repeated infusions are needed if non-retroviral vectors are used, or if mature cells are used), it provided significant improvement in immune function and demonstrated the potential of gene therapy to correct genetic defects, offering hope for treating many other inherited diseases.
2. Explain the application of biotechnology in agriculture with a focus on Genetically Modified Organisms (GMOs) and Bt crops. Discuss the ethical considerations and biosafety issues associated with the use of GMOs.
Answer:
Application of Biotechnology in Agriculture: Biotechnology has significantly impacted agriculture by enabling the development of genetically modified organisms (GMOs) with improved traits, leading to increased productivity and reduced reliance on traditional methods.
Genetically Modified Organisms (GMOs): GMOs are plants, animals, or microorganisms whose genetic material has been altered in a way that does not occur naturally by mating and/or natural recombination. In agriculture, GMOs typically refer to genetically modified (GM) crops.
Advantages of GMOs in Agriculture:
Enhanced Crop Yield: Increased resistance to pests, diseases, and environmental stresses.
Reduced Reliance on Chemical Pesticides: Especially with pest-resistant crops like Bt cotton.
Improved Nutritional Value (Biofortification): Crops engineered to be richer in vitamins, minerals, or proteins (e.g., Golden Rice with Vitamin A).
Increased Efficiency of Mineral Usage by Plants: Less depletion of soil fertility.
Development of Stress-Tolerant Crops: Tolerant to drought, salinity, heat, cold.
Reduced Post-harvest Losses: (e.g., Flavr Savr tomato with delayed ripening).
Bt Crops (A prominent example of GMOs): Bt crops are genetically modified plants that produce their own insecticide.
Origin: The insecticide is derived from a bacterium called Bacillus thuringiensis (Bt). This bacterium produces proteins (Bt toxins) that are toxic to certain insect pests but harmless to humans, other animals, and beneficial insects.
Mechanism: Specific genes from Bacillus thuringiensis (called cry genes, e.g., cryIAc, cryIIAb for cotton bollworms; cryIAb for corn borer) are isolated and transferred into the genome of crop plants (e.g., cotton, corn, brinjal).
Action: When an insect pest (e.g., cotton bollworm) feeds on the Bt cotton plant, it ingests the inactive Bt protoxin. In the alkaline pH of the insect's gut, the protoxin is activated. The activated toxin then binds to specific receptors on the midgut epithelial cells, creating pores. This causes swelling and lysis of the gut cells, leading to the death of the insect larva.
Benefits: Reduces the need for chemical insecticide sprays, leading to lower production costs, less environmental pollution, and potentially higher yields.
Ethical Considerations and Biosafety Issues Associated with GMOs:
The use of GMOs raises several ethical and biosafety concerns that require careful consideration and regulation:
Ecological and Environmental Concerns:
Gene Flow: Potential for genes from GM crops (e.g., herbicide resistance) to escape and transfer to wild relatives through cross-pollination, leading to "superweeds."
Impact on Non-Target Organisms: Bt toxins, though specific to certain pests, might potentially harm beneficial insects (e.g., pollinators like butterflies) if not managed properly.
Loss of Biodiversity: Widespread cultivation of a few GM varieties might reduce genetic diversity in crop plants and their wild relatives.
Development of Resistance: Continuous exposure to Bt toxin might lead to the evolution of resistant insect populations, rendering the technology ineffective over time.
Health Concerns:
Allergenicity: New proteins introduced into GM foods might act as allergens in some individuals.
Toxicity: Although rigorously tested, long-term effects of consuming GM foods are still debated by some.
Antibiotic Resistance Markers: Some early GM crops used antibiotic resistance genes as selectable markers. There were concerns about these genes potentially transferring to gut bacteria, leading to antibiotic resistance in humans, though this risk is generally considered low.
Ethical and Socio-economic Issues:
Biopiracy: Unethical exploitation of bioresources (e.g., traditional knowledge, native plants) of a country or community by multinational companies without proper authorization or compensation.
Patents: Granting patents on genes, genetically modified organisms, and processes can lead to monopolization by large corporations, potentially disadvantaging small farmers and hindering public research.
Access and Equity: Concerns about GM crops being owned by a few companies, potentially making seeds expensive and inaccessible for poorer farmers, exacerbating social inequalities.
Cultural and Religious Objections: Some groups have ethical or religious objections to manipulating life forms.
Regulatory bodies (like GEAC in India - Genetic Engineering Appraisal Committee) are established to evaluate the safety of GM research and introduce GM organisms for public use, aiming to balance the benefits with potential risks.
3. Explain the concept of biopiracy and its implications. How do patents play a role in this context? Provide examples to illustrate the concept.
Answer:
Concept of Biopiracy: Biopiracy refers to the unauthorized and uncompensated appropriation or commercial exploitation of biological resources and/or traditional knowledge belonging to a community or country, particularly by multinational corporations from developed countries. It involves using genetic resources or traditional knowledge (often from indigenous or local communities in developing nations) without obtaining proper informed consent and without sharing the benefits fairly with the original custodians of those resources and knowledge.
Key Aspects of Biopiracy:
Unauthorized Use: Use of biological resources or traditional knowledge without permission from the legitimate owners/communities.
Lack of Compensation: Failure to provide fair and equitable benefit-sharing to the communities whose resources or knowledge were utilized.
Patent Exploitation: Obtaining patents on products or processes derived from these resources/knowledge, thereby establishing exclusive rights without acknowledging or compensating the originators.
Implications of Biopiracy: Biopiracy has several negative implications:
Economic Disadvantage:
It deprives local communities and developing nations of potential economic benefits from their own bioresources and traditional knowledge, perpetuating inequality.
Erosion of Traditional Knowledge:
It can undermine and devalue traditional knowledge systems, as indigenous practices are often exploited without recognition or respect.
Loss of Sovereignty:
It challenges the sovereignty of nations over their genetic resources, as foreign entities claim ownership.
Ethical Concerns:
It raises fundamental ethical questions about intellectual property rights, justice, and the ownership of life forms and traditional wisdom.
Environmental Impact:
Uncontrolled exploitation can sometimes lead to depletion of certain valuable biological resources.
Trust Deficit:
It creates mistrust between developing countries/indigenous communities and multinational corporations/developed nations.
Role of Patents in Biopiracy: Patents are central to the issue of biopiracy. A patent grants exclusive rights to an inventor for a specific period (usually 20 years) to prevent others from making, using, or selling the invention without permission. In the context of biopiracy:
Multinational companies often identify valuable genes, compounds, or processes from biological resources (plants, animals, microbes) or traditional practices used in developing countries.
They then modify these resources/processes slightly or isolate specific compounds and file for patents in their own countries or internationally.
Once a patent is granted, they gain exclusive rights to commercialize the product or process, effectively preventing the original communities or countries from freely using or benefiting from their own resources/knowledge.
This creates a situation where the original developers or custodians of the knowledge and resources receive no credit or compensation, while others profit immensely.
Examples to Illustrate Biopiracy:
Neem (India):
Traditional uses of the Neem tree (medicinal, pesticidal, fungicidal) have been known and used in India for centuries.
However, several patents were granted in the US and Europe to companies for Neem-derived products, particularly for its pesticidal properties.
For example, a patent was granted to the US Department of Agriculture and a company named W.R. Grace for a method of extracting azadirachtin (a pesticidal compound) from Neem seeds. This was challenged and eventually revoked in Europe due to lack of novelty, highlighting the prior art of traditional knowledge.
Basmati Rice (India):
Basmati is a unique, aromatic variety of rice traditionally cultivated for centuries in the Indian subcontinent.
In 1997, a US company, RiceTec, was granted a patent on a "Basmati rice plant and grains" and lines derived from Basmati, despite the long-standing traditional cultivation.
This patent implied that RiceTec could claim exclusive rights to market Basmati rice in the US and potentially elsewhere, which was a clear case of biopiracy of a traditionally known product. After international outcry, many of the patent claims were withdrawn or limited.
Turmeric (India):
The medicinal properties of turmeric (e.g., wound healing) have been part of traditional Indian medicine for thousands of years.
A patent was granted in the US for the use of turmeric powder for wound healing. This patent was challenged by India and successfully revoked in 1997, again based on the concept of "prior art" from traditional knowledge.
These examples underscore the need for international frameworks, like the Nagoya Protocol (under the Convention on Biological Diversity), that promote Access and Benefit-Sharing (ABS) to prevent biopiracy and ensure fair and equitable sharing of benefits arising from the utilization of genetic resources.
