Biotechnology and Its Applications - Class 12 Biology - Chapter 10 - Notes, NCERT Solutions & Extra Questions
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Which part of the plant is best suited for making virus-free plants and why?
The meristematic tissue (specifically the apical and axillary meristems) is best suited for making virus-free plants. This is because meristematic regions are usually free from viral infections even if the rest of the plant is infected. Therefore, by extracting and culturing the meristem tissues in vitro, it is possible to generate virus-free plants.
Here's a brief process:
Extract the meristem from an infected plant.
Cultivate it in a sterile, nutrient-rich medium to grow virus-free plants.
This method has been successfully used for plants like banana, sugarcane, and potato.
What is the major advantage of producing plants by micropropagation?
The major advantage of producing plants by micropropagation is that it allows for the rapid propagation of a large number of genetically identical plants. This method results in plants that are clones of the original plant, ensuring uniformity and consistency in the crop. Additionally:
It helps in the propagation of plants that are difficult to grow from seeds.
It allows for the production of disease-free plants by selecting virus-free explants.
It enables conservation of endangered plant species by producing many plants from a small amount of tissue.
This process is particularly useful for commercial production of important food plants such as tomato, banana, and apple.
Find out what the various components of the medium used for propagation of an explant in vitro are?
To propagate an explant in vitro, tissue culture techniques are used, requiring a specialized nutrient medium. The components of this medium include:
Carbon Source:
Typically sucrose is used as an energy source.
Inorganic Salts:
Essential mineral ions such as nitrates, phosphates, and sulfates of elements like nitrogen, phosphorus, potassium, calcium, magnesium, and iron.
Vitamins:
Vitamins like B1 (thiamine), B6 (pyridoxine), niacin, and myoinositol which are crucial for growth and development.
Amino Acids:
Amino acids to provide basic building blocks for protein synthesis.
Growth Regulators:
Auxins (e.g., Indole-3-acetic acid) and cytokinins (e.g., Kinetin) to regulate cell division and differentiation.
Other Organic Compounds:
Substances like adenine sulfate and gibberellins which may promote growth.
The sterile environment and proper balance of these components are what enable the successful regeneration of whole plants from explants.
Crystals of Bt toxin produced by some bacteria do not kill the bacteria themselves because -
(a) bacteria are resistant to the toxin
(b) toxin is immature;
(c) toxin is inactive;
(d) bacteria encloses toxin in a special sac.
Crystals of Bt toxin produced by some bacteria do not kill the bacteria themselves because (c) toxin is inactive.
The Bt toxin protein is produced as an inactive protoxin. It becomes active only when it is ingested by insects and converted into an active form in the alkaline pH of the insect gut. This mechanism ensures that the toxin does not harm the bacteria that produce it.
What are transgenic bacteria? Illustrate using any one example.
Transgenic bacteria are bacteria that have been genetically engineered to contain genes from other organisms. These genes enable the bacteria to produce proteins or other molecules that they would not naturally produce. One of the most famous examples of transgenic bacteria involves the production of human insulin.
Example: Production of Human Insulin by E. coli
Human insulin is a vital therapy for diabetes, a condition where the body does not produce enough insulin. Insulin used to be extracted from the pancreas of slaughtered animals, but this was not always effective and could cause immune reactions in some patients.
The production of human insulin using recombinant DNA technology involves the following steps:
Isolation of the Human Insulin Gene:The gene responsible for insulin production is isolated from human DNA.
Insertion into Bacterial Plasmid:This gene is inserted into a plasmid (a small, circular piece of DNA) from the bacterium *E. coli*.
Transformation:The plasmid is then introduced into *E. coli* cells. The bacteria take up the plasmid and begin to express the gene, producing the human insulin protein.
Culturing the Bacteria:The transformed bacteria are cultured in large quantities, allowing for mass production of insulin.
Extraction and Purification:The insulin produced by the bacteria is then extracted and purified for medical use.
This method allows for large-scale production of human insulin, which is identical to the insulin produced in the human body and does not cause adverse immune responses.
Compare and contrast the advantages and disadvantages of production of genetically modified crops.
Advantages
Increased Tolerance to Abiotic Stresses:
Genetically modified crops can be made more tolerant to abiotic stresses such as cold, drought, salt, and heat. This leads to better crop survival and yield in adverse climatic conditions.
Reduced Reliance on Chemical Pesticides:
The production of pest-resistant crops (like Bt cotton) helps in decreasing the use of chemical pesticides, which is beneficial for both the environment and human health. Bt toxin gene, derived from the bacterium *Bacillus thuringiensis*, is expressed in GM crops to resist insect attacks.
Reduction in Post-Harvest Losses:
Genetic modifications help in reducing losses that occur after harvesting, thus improving the efficiency of food production.
Increased Efficiency of Mineral Usage:
GM crops enhance the efficiency of mineral uptake from the soil, preventing the early exhaustion of soil fertility.
Enhanced Nutritional Value:
Some GM crops have been developed to have enhanced nutritional content, such as Vitamin A enriched golden rice, which can help combat nutritional deficiencies in developing countries.
Alternative Resources for Industry:
GM crops can be tailored to produce unique starches, fuels, and pharmaceuticals, providing alternative resources to various industries.
Disadvantages
Environmental Impact:
The introduction of GM crops to the environment can have unpredictable effects on ecosystems. There is a risk of gene flow to non-GM crops and wild relatives, which may result in the emergence of superweeds or pest-resistant pests.
Ethical Concerns:
The manipulation of genetic material in organisms raises significant ethical issues. There is a debate over the extent of human intervention in natural genetic processes.
Economic Concerns:
Farmers may become dependent on seeds from biotech companies, leading to concerns about monopolies and increased costs for farmers in the developing world.
Potential Health Risks:
There is ongoing debate and research about the long-term health effects of consuming GM foods. Some concerns include allergenicity and the introduction of new toxins.
Loss of Biodiversity:
The widespread use of GM crops can lead to a reduction in genetic diversity within crop species. This could make crops more vulnerable to diseases and pests in the long term.
Resistance Development:
Pests and weeds might develop resistance to the traits introduced by genetic modifications, leading to the emergence of resistant species that are even harder to control.
What are Cry proteins? Name an organism that produce it. How has man exploited this protein to his benefit?
Cry proteins are insecticidal proteins produced by the bacterium Bacillus thuringiensis (Bt). These proteins have the ability to kill certain insect species by causing cell swelling and lysis.
Exploitation by Humans
Humans have exploited Cry proteins for agricultural benefits by incorporating the gene responsible for Cry protein production into crop plants. This genetic modification has led to the creation of several Bt crops such as Bt cotton, Bt corn, and Bt potato.
Benefits of Bt Crops
Pest Resistance: Bt crops are resistant to specific insect pests, reducing the need for chemical pesticides.
Reduction in Pesticide Use: The inherent pest resistance of Bt crops allows farmers to use fewer chemical pesticides, promoting a more environmentally friendly agricultural practice.
Improved Yield: With reduced pest damage, the overall crop yield is often improved, benefitting food production.
By integrating the Cry protein gene into crops, humans have developed a biological method to combat pest problems, leading to more sustainable and productive farming practices.
What is gene therapy? Illustrate using the example of adenosine deaminase (ADA) deficiency.
Gene therapy is a collection of techniques aimed at correcting a gene defect that has been diagnosed in a child or embryo. The process involves inserting normal genes into a person's cells and tissues to treat a disease. The goal is to replace a defective mutant allele with a functional one.
Example: Adenosine Deaminase (ADA) Deficiency
Adenosine deaminase (ADA) deficiency is a genetic disorder that affects the immune system. Without ADA, deoxyadenosine builds up in lymphocytes (a type of white blood cell) and destroys them, resulting in severe immunodeficiency.
Standard Treatment Methods:
Bone marrow transplantation
Enzyme replacement therapy – Functional ADA is injected into the patient.
These methods are not completely curative and only provide temporary relief.
Gene Therapy Approach:
Lymphocyte Isolation:
Lymphocytes are extracted from the patient's blood.
Gene Insertion:
A functional ADA gene is inserted into these lymphocytes using a retroviral vector.
Cell Culture:
The genetically modified lymphocytes are cultured outside the body to increase their number.
Reintroduction:
These modified lymphocytes are then reintroduced into the patient's bloodstream.
Since lymphocytes are not immortal, patients require periodic infusions. However, if the ADA gene could be introduced into stem cells at an early embryonic stage, it could potentially provide a permanent cure.
Visual Illustration
Here is a simplified diagram of the steps involved in gene therapy for ADA deficiency:
+--------------------------+ +---------------------+
| Patient | | Retroviral Vector |
| Lymphocytes (blood) | | with Functional |
| + Extraction +----------------> ADA Gene |
| | | |
+------------+-------------+ +---------+-----------+
| |
| |
+-----v------^-----+ +-----v------^-----+
| | | |
| Culturing of +<---------------------> Gene Insertion |
| Lymphocytes | | |
| (Growth Outside | | |
| the Body) | | |
+------------+-------+ +----------+---------+
| |
^ |
+-------------+-------^ +----------+---------+
| | | |
| Reintroduction into +<--------------------> Functional ADA |
| Patient's Bloodstream | | Gene Lymphocytes |
| | | |
+-------------------------+ +--------------------+
This process illustrates how gene therapy can restore immunity in patients with ADA deficiency by replacing defective genes with functional ones.
Digrammatically represent the experimental steps in cloning and expressing an human gene (say the gene for growth hormone) into a bacterium like E. coli?
To represent the experimental steps in cloning and expressing a human gene, such as the gene for growth hormone, into a bacterium like _E. coli_, follow these steps:
1. Isolate Human Gene
Human cells are obtained, and the specific gene for growth hormone is isolated using restriction enzymes.
2. Prepare Plasmid Vector
A plasmid from _E. coli_ is isolated and cut open using the same restriction enzyme to create sticky ends compatible with the human growth hormone gene.
3. Ligate Gene into Vector
The human growth hormone gene is inserted into the plasmid vector using DNA ligase, which seals the sugar-phosphate backbone.
4. Transform Bacteria
The recombinant plasmid is introduced into _E. coli_ cells through a process called transformation.
5. Select Transformed Bacteria
Bacteria are grown on a medium containing an antibiotic, and only bacteria that have taken up the plasmid, which also carries an antibiotic resistance gene, will survive.
6. Screen for Recombinants
Screening methods like PCR or restriction digestion are used to confirm the presence of the recombinant plasmid.
7. Express the Gene
Induce the bacterial cells to express the human growth hormone gene, often using an inducer like IPTG.
8. Harvest and Purify Protein
The bacterial cells are lysed, and the growth hormone protein is purified using techniques such as affinity chromatography.
Here's a diagram to summarize the process:
1. Isolate Human Gene ➜ 2. Prepare Plasmid Vector ➜ 3. Ligate Gene into Vector
(a)⮟ (a)⮟ (a)⮟
1a. Extract human DNA 2a. Use restriction enzyme 3a. Insert gene
1b. Isolate gene of interest 2b. Open plasmid 3b. Ligate
4. Transform Bacteria ➜ 5. Select Transformed Bacteria ➜ 6. Screen for Recombinants
(a)⮟ (a)⮟ (a)⮟
4a. Insert plasmid 5a. Grow in antibiotic media 6a. PCR/Restriction digestion
4b. Use heat shock 5b. Identify colonies
7. Express the Gene ➜ 8. Harvest and Purify Protein
(a)⮟ (a)⮟
7a. Induce expression 8a. Lyse cells
7b. IPTG as inducer 8b. Purify protein
This simplified flowchart provides an overview of the main steps involved in cloning and expressing a human gene in _E. coli_.
Can you suggest a method to remove oil (hydrocarbon) from seeds based on your understanding of rDNA technology and chemistry of oil?
One possible method to remove oil (hydrocarbon) from seeds using rDNA technology could involve the following steps:
Enzyme Production using rDNA Technology:
Identify and Isolate the Enzyme: Identify enzymes that can break down hydrocarbons, such as lipases or other specific enzymes that can degrade oils. Lipases catalyze the hydrolysis of fats into glycerol and fatty acids.
Insert the Gene into a Host: Use recombinant DNA technology to insert the gene that codes for the hydrocarbon-degrading enzyme into a suitable microbial host (e.g., *E. coli* or *Saccharomyces cerevisiae*).
Microbial Fermentation:
Grow the Recombinant Microbes: Culture the genetically modified microbes in a fermenter. These microbes will produce the hydrocarbon-degrading enzyme in large quantities.
Enzyme Application:
Extract and Purify the Enzyme: Purify the enzyme from the microbial culture.
Treat the Seeds: Treat the oil-containing seeds with the enzyme. The enzyme will break down the oil into simpler, more soluble components.
Oil Removal:
Washing and Separation: Wash the treated seeds to remove the hydrolyzed oil components. This can be done using an aqueous or mildly acidic solution to ensure complete removal.
Biochemical Considerations
The lipase enzyme catalyzes the hydrolysis of triglycerides (which are the main components of seed oil) into glycerol and free fatty acids through the following reaction: $$ \text{Triglyceride} + 3 \text{H}_2\text{O} \xrightarrow{\text{Lipase}} \text{Glycerol} + 3 \text{Fatty Acids} $$
rDNA Technology Steps
Gene Identification: Identify the gene encoding the desired lipase enzyme.
Gene Insertion: Insert the gene into a plasmid vector.
Transformation: Introduce the plasmid into a microbial host.
Expression: Culture the host cells to express the enzyme.
Enzyme Extraction: Extract the enzyme from the microbial cultures for use in oil degradation.
By employing this method, the oil can be effectively broken down and removed, thereby making the seeds usable for other applications. This approach leverages the specificity and efficiency of the enzymatic action facilitated by genetically engineered organisms.
Find out from internet what is golden rice.
Golden Rice is a genetically modified variety of rice that has been engineered to contain high levels of beta-carotene, a precursor to Vitamin A. It was developed to address Vitamin A deficiency, which is prevalent in many parts of the world and can lead to blindness and other health issues.
Here are some key points about Golden Rice:
Genetic Modification: The rice is genetically modified to produce beta-carotene in the edible parts of the rice plant.
Vitamin A Enrichment: The primary objective is to combat Vitamin A deficiency, particularly in regions where the population relies heavily on rice as a staple food.
Development: It was first developed by scientists Ingo Potrykus and Peter Beyer in the late 1990s.
Scientific Name: *Oryza sativa* modified with genes from *daffodil* (originally used genes from *daffodil*, later replaced with genes from maize for better efficiency).
The visual characteristic of Golden Rice is its yellow-orange coloration, which is due to the beta-carotene. This rice is intended to be a cost-effective intervention for alleviating Vitamin A deficiency in impoverished areas.
Does our blood have proteases and nucleases?
Yes, our blood does contain proteases and nucleases.
Proteases are enzymes that break down proteins. They play a key role in various physiological processes including digestion, blood clotting, and immune response.
Nucleases are enzymes that cleave the chains of nucleotides in nucleic acids. They are crucial for processes like DNA repair, replication, and the degradation of foreign DNA and RNA.
These enzymes ensure that damaged or unnecessary proteins and nucleic acids are efficiently broken down and removed from the bloodstream.
Consult internet and find out how to make orally active protein pharmaceutical. What is the major problem to be encountered?
An orally active protein pharmaceutical is a protein-based drug that can be effectively administered by mouth. Here is an overview of how such pharmaceuticals are developed and the challenges encountered:
Steps to Make Orally Active Protein Pharmaceuticals:
Stabilization: Proteins must be stabilized against the harsh conditions of the gastrointestinal (GI) tract. This can involve:
Chemical modification: Adding molecules to the protein to protect it.
Encapsulation: Using materials such as polymers or lipids to encase the protein.
Formulation: Developing tablet or capsule forms that protect the protein during digestion.
Protection from Enzymes: Proteins are susceptible to degradation by proteolytic enzymes in the stomach and intestines. Techniques include:
Protease inhibitors: Adding substances that inhibit digestive enzymes.
Enteric coatings: Coating the tablet or capsule to prevent release until it reaches the less acidic intestines.
Enhancement of Absorption: The large size and polarity of proteins make it difficult for them to pass through the intestinal wall. Methods to enhance absorption include:
Permeation enhancers: Substances that increase the permeability of the intestinal lining.
Nanoparticles: Using nano-sized carriers to facilitate transport across the gut barrier.
Major Problems Encountered:
Degradation in the GI Tract: The primary issue is that proteins are broken down by stomach acids and digestive enzymes before they can be absorbed.
Low Bioavailability: Even if the protein survives the GI tract, it often doesn't pass easily through the intestinal walls into the bloodstream.
Manufacturing Complexity: Producing stable formulations that can withstand the GI environment and still be biologically active is complex and costly.
Potential for Immune Response: Orally administered proteins may induce immune responses or allergies.
Conclusion:
Creating orally active protein pharmaceuticals involves advanced drug design to protect the protein's integrity and ensure efficient absorption. The major problem is the degradation of proteins in the GI tract, which greatly limits the effectiveness of these drugs when administered orally. Researchers are actively exploring innovative strategies to overcome these challenges.
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Notes - Biotechnology and Its Applications | Class 12 NCERT | Biology
Comprehensive Class 12 Notes on Biotechnology and Its Applications
Biotechnology is a fascinating field that significantly impacts agricultural and medical advancements. Let's delve into the key concepts of biotechnology and its myriad applications.
Understanding Biotechnology
Biotechnology involves using living organisms, biological systems, or their derivatives to create, modify, or enhance products and processes. The main research areas are:
- Improving organisms as catalysts, usually through microbes or pure enzymes.
- Creating optimal conditions for these catalysts.
- Developing downstream processing technologies for purification.
Biotechnological Applications in Agriculture
Increasing Food Production
To meet the growing population's food demands, three methods are adopted:
- Agro-chemical based agriculture
- Organic agriculture
- Genetically engineered crop-based agriculture
Tissue Culture: Definition and Applications
Tissue culture involves growing plants from explants under sterile conditions, enabling rapid and large-scale plant production. This process is termed micro-propagation. It allows the creation of genetically identical plants called somaclones. It's widely used for crops like tomatoes, bananas, and apples.
Genetically Modified Organisms (GMOs)
GMOs are organisms whose genetic material has been artificially modified. They offer numerous benefits:
- Tolerance to abiotic stresses (e.g., drought, heat)
- Reduced reliance on chemical pesticides
- Decreased post-harvest losses
- Enhanced nutritional value (e.g., Golden Rice enriched with Vitamin A)
- Tailor-made plants for industrial purposes (e.g., pharmaceuticals, fuels)
Bt Cotton: Mechanism and Benefits
Bt cotton is engineered to produce a toxin from Bacillus thuringiensis, effective against certain pests. The inactive protoxins in the plant activate in the insect's alkaline gut, causing cell lysis and death.
graph TB
A[Cotton Plant] -- Produce Bt Toxin Gene --> B[Bacillus thuringiensis]
B -- Protoxins --> C[Inactive Protoxins in Plant]
C -- Ingestion by Insect --> D[Activation in Alkaline Gut]
D --> E[Pest Death]
RNA Interference in Pest-Resistant Plants
RNA interference (RNAi) is a cellular defence method where a complementary RNA molecule silences specific mRNA. This technique is used to create plants resistant to pests like nematodes.
Biotechnological Applications in Medicine
Role of Recombinant DNA Technology in Healthcare
Recombinant DNA technology enables the mass production of safe, effective therapeutic drugs, avoiding unwanted immune reactions.
Genetically Engineered Insulin
Using recombinant DNA, human insulin can be produced in bacteria, providing an effective treatment for diabetes without relying on animal insulin.
graph TD
A[Pro-Insulin] -->|Removal of C-Peptide| B[Mature Insulin]
C[E. Coli] -- Introduced into --> D[Produces Insulin Chains]
D -->|Combines Chains| B
Gene Therapy: Process and Applications
Gene therapy involves inserting functional genes into an individual to correct genetic defects. The first clinical gene therapy was for ADA deficiency, crucial for immune function.
Techniques in Molecular Diagnosis
- PCR (Polymerase Chain Reaction): Amplifies DNA to detect low concentrations of pathogens.
- ELISA (Enzyme-Linked Immunosorbent Assay): Uses antigen-antibody interaction to detect pathogens.
Transgenic Animals
What are Transgenic Animals?
Transgenic animals have foreign genes incorporated into their DNA. Over 95% of such animals are mice, used for various studies and applications.
Applications:
- Understanding Physiology and Development: Study gene regulations and body functions.
- Study of Diseases: Model human diseases like cancer and Alzheimer's.
- Production of Biological Products: Produce human proteins for medical use.
- Vaccine Safety: Test vaccine safety through models like transgenic mice.
- Chemical Safety Testing: Assess the toxicity of substances using sensitive transgenic animals.
Ethical Issues in Biotechnology
Ethical Considerations and Regulatory Frameworks
Biotechnology's manipulation of organisms necessitates ethical standards to ensure safety and fairness. India's Genetic Engineering Approval Committee (GEAC) oversees GM research and applications.
Examples of Biopiracy
Instances like the patenting of Basmati rice and traditional herbal medicines by foreign companies highlight ethical and legal concerns over biopiracy.
India's Response to Biopiracy and Patenting Issues
India is developing laws and amendments, such as the Indian Patents Bill, to protect its biological resources and traditional knowledge from unauthorised exploitation.
Summary and Future Prospects
Biotechnology has revolutionised agriculture and healthcare, offering innovative solutions and products. From GMOs enhancing crop yields to recombinant DNA producing essential medicines, the future holds immense potential. However, ethical oversight and proper regulations are crucial to ensuring its benefits are safely and equitably realised.
This comprehensive overview of biotechnology and its applications provides essential insights for class 12 students, highlighting both the scientific advancements and the ethical considerations involved.
By incorporating these elements into our notes, we ensure a balanced and detailed understanding of biotechnology, suitable for academic and practical purposes.
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