Class 12 Biology Chapter 10 Biotechnology and Its Applications

Key Concept:Advanced Application, Real-World Problem Solving

a) Ensure correct isolation and purification of protoplasts, followed by their fusion using PEG.
[Solution Description] To achieve a successful somatic hybrid that retains both drought resistance and high yield, several critical steps need to be followed. Initially, the protoplasts must be accurately isolated by removing the cell walls using enzymatic digestion. Then, effective fusion techniques such as polyethylene glycol (PEG) or electrofusion are required to merge the protoplasts. Afterward, regenerate the hybrid cells into whole plants under suitable conditions that maintain both traits. Lastly, evaluate the physiological and genetic stability of these traits through rigorous testing and selection.

Key Concept: Concept Recognition

d) Bacillus thuringiensis

[Solution Description] Bt toxin is derived from the bacterium Bacillus thuringiensis. This bacterium synthesizes proteins that are toxic to certain insect larvae, making it useful in developing pest-resistant crops.

Key Concept:Permanent Cure

c) Integrating ADA gene into early embryonic cells
[Solution Description]
For a permanent cure of ADA deficiency, the preferred strategy would involve integrating a functional copy of the ADA gene into early embryonic cells. This approach ensures that all cells derived from these embryonic cells will have a functioning ADA gene, potentially curing the disease at its root cause permanently.

Key Concept: Insulin Synthesis, Genetic Engineering

c) It allows the precise assembly of A and B chains without interference.

[Solution Description] In the synthesis of insulin, it is initially produced as a pro-hormone with an extra C-peptide that connects A and B chains. The removal of this C peptide during maturation is crucial for forming the active insulin molecule. For recombinant production, creating separate DNA sequences for the A and B chains allows their independent expression and folding into native conformations before linking through disulfide bonds. This separation simplifies translation and folding processes within bacterial cells like E. coli, minimizing structural complications and allowing efficient processing to produce functional insulin.

Key Concept: Retroviral Vector

c) They integrate the gene into the host genome for stable expression

[Solution Description] Retroviral vectors are commonly used in gene therapy because they have the ability to integrate their genetic material into the host genome, thereby providing stable and long-term expression of the introduced gene. This makes them suitable for therapies that require sustained gene expression.

Key Concept:Pathogen Detection

b) To amplify DNA for detection
[Solution Description] PCR allows for the amplification of DNA sequences present in very small quantities. This makes it possible to detect pathogenic DNA even when present only in trace amounts, allowing detection before symptoms become apparent.

Key Concept: ELISA Specificity

b) Antigens

[Solution Description] ELISA employs antigen-antibody interactions to detect specific proteins such as antigens or antibodies in a sample. This specificity makes it ideal for identifying infections by recognizing pathogen antigens or patient-produced antibodies against pathogens.

Key Concept:Real-world Application, Synthesis

c) Promote precision agriculture technologies
[Solution Description] Policymakers could promote precision agriculture, which utilizes technology to apply agrochemicals more efficiently and precisely only where needed. This reduces waste and minimizes environmental damage. Encouraging research and development in sustainable farming practices would support long-term productivity while protecting ecosystems.

Key Concept:Application Recognition

c) HIV
[Solution Description] Molecular diagnosis techniques can be used to detect diseases such as HIV, cancer mutations, and genetic disorders before symptoms appear, allowing for early treatment.

Key Concept: Disease Study

b) Cancer

[Solution Description] Transgenic animals, such as mice, are extensively used to study complex diseases at genetic and molecular levels. Cancer, diabetes, and cystic fibrosis are among the diseases modeled using these animals to understand disease mechanisms or test potential treatments.

Key Concept:Bt Toxin Activation

c) Alkaline pH
[Solution Description] The alkaline pH in the insect gut is necessary for the activation of the Bt toxin. Under these conditions, the protoxin form of Bt is cleaved into an active toxin that can bind to the insect’s gut cells, causing cell lysis and eventually insect death.

Key Concept:GMO Environmental Impact

b) By reducing reliance on chemical pesticides
[Solution Description] Genetically modified organisms contribute to environmental protection mainly by reducing reliance on chemical pesticides. Many GMOs are engineered to be resistant to pests, which reduces the need for farmers to apply chemical pesticides that can harm non-target species and cause pollution. Additionally, GMOs can improve mineral usage efficiency and enhance nutritional value, but their direct contribution to environmental protection comes from minimizing pesticide use.

Key Concept:Early Diagnosis Importance

d) It allows for timely intervention
[Solution Description] Early diagnosis is vital because it allows for timely intervention, which can lead to better treatment outcomes and may prevent further disease progression, ultimately improving patient prognosis.

Key Concept:Complex Gene Interactions, Advanced Disease Models

d) Amyloid precursor protein processing
[Solution Description] Alzheimer’s disease in transgenic models is often studied by altering amyloid precursor protein processing pathways. This pathway’s malfunction leads to the accumulation of beta-amyloid plaques, a hallmark of Alzheimer’s disease. By modifying these gene expressions, researchers can observe and analyze how these changes affect neural degeneration and cognitive functions.

Key Concept:Pathogen Detection

c) PCR
[Solution Description] PCR is a technique widely used for the early detection of pathogens. It is capable of amplifying small amounts of DNA or RNA, making it possible to identify and quantify pathogens present at low concentrations before clinical symptoms manifest.

Key Concept:Advanced Totipotency, Micro-propagation Challenges

c) Utilizing meristem tissues which are typically free from viral infection.
[Solution Description] To develop virus-free plants using micro-propagation by exploiting totipotency, one approach is to culture the meristematic tissues of a plant. These tissues are often free from viruses due to their location and rapid growth rates. The totipotent nature allows these cells to regenerate into complete, healthy plants devoid of viral contamination. By focusing on apical or axillary meristems, which are less likely to harbor viruses, we can effectively utilize totipotency in tissue culture processes.

Key Concept:Basic Concept

c) For testing vaccine safety
[Solution Description] Transgenic mice are primarily used for testing the safety of vaccines before human use because they can model human responses to vaccines.

Key Concept:Basic Concept

d) To amplify nucleic acids
[Solution Description] The primary purpose of using PCR (Polymerase Chain Reaction) is to amplify nucleic acids, which helps in detecting low concentrations of pathogens.

Key Concept:Genetic Engineering, Environmental Impact

b) cryIAc and cryIIAb
[Solution Description] To address the issue of resistance and tackle diverse pests, incorporating multiple Bt genes targeting different pests would be effective. The cryIIAb gene targets some pests not affected by cryIAc, providing a broader spectrum of protection. Combining cryIAc with cryIIAb can cover various pests. Additionally, using these combinations could reduce reliance on chemical pesticides, thus decreasing environmental impact.

Key Concept:Genetic Engineering Process, Bt Toxin Specificity

b) They specifically target lepidopteran larvae but may be ineffective against coleopterans or dipterans.
[Solution Description]
The cryIAc and cryIIAb genes encode Bt toxin proteins that specifically target lepidopteran larvae such as cotton bollworms and corn borers. These genes produce proteins that are activated in the alkaline conditions of insect midguts, where they bind to specific receptors, creating pores in the midgut cells, and ultimately causing insect death. However, these Bt toxins are generally specific to certain orders of insects and may not effectively target non-lepidopteran pests such as coleopterans or dipterans due to different receptor sites or gut conditions.

Key Concept:Gene Therapy Process

a) Functional ADA cDNA
[Solution Description] The gene therapy process for ADA deficiency involves introducing functional ADA cDNA into the patient’s lymphocytes using retroviral vectors. This enables the lymphocytes to produce the ADA enzyme, compensating for the deficiency.

Key Concept:Basic Definition

c) To make them sensitive to toxic substances
[Solution Description] The primary goal of using transgenic animals in toxicity testing is to make them sensitive to toxic substances, allowing researchers to observe and measure the effects more quickly than traditional methods. This sensitivity helps speed up the process of identifying toxic substances.

Key Concept:Establishment Purpose

c) To ensure safe use of GM organisms
[Solution Description] The GEAC was established by the Indian Government to ensure safe research, development, and release of genetically engineered organisms or products. Its purpose is to evaluate potential risks and benefits associated with genetic modifications and to approve or disapprove such projects based on safety assessments.

Key Concept:Genetic Engineering Technique, Biotechnological Impact

c) Gene cloning using plasmid vectors in bacterial hosts
[Solution Description]
Large-scale production of human insulin became feasible due to advancements in recombinant DNA technology, particularly gene cloning. This technique allowed scientists to insert the human insulin gene into bacteria such as E. coli, enabling these microorganisms to produce insulin identical to that produced by humans. This method overcame issues associated with animal-derived insulins, such as immunogenicity, thus providing a safer and more efficient means of production.

Key Concept:Protoplast Fusion

c) A somatic hybrid with combined traits.
[Solution Description] Protoplast fusion involves combining the cellular contents from two different plant varieties, leading to the formation of somatic hybrids with combined characteristics of both parent plants.

Key Concept:Human Protein in Milk

b) Alpha-lactalbumin
[Solution Description] The milk produced by Rosie the cow, a transgenic animal, is enriched with the human protein alpha-lactalbumin. This protein is beneficial for infant nutrition as it plays a role in lactose synthesis.

Key Concept:Purpose of GMOs

c) To enhance desirable traits like pest resistance
[Solution Description] One of the main purposes of genetically modifying organisms is to enhance their traits such as increasing crop yield, improving nutritional value, or providing resistance to pests and diseases.

Key Concept:Advanced Mechanism, Molecular Interaction

c) It directs RISC to degrade or block translation of target mRNA.
[Solution Description] The mechanism by which RNAi operates begins with the introduction of dsRNA into the cell. This dsRNA is recognized by an enzyme called Dicer, which cleaves it into small fragments known as small interfering RNAs (siRNAs). These siRNAs are then incorporated into a protein complex called RISC (RNA-induced silencing complex). The siRNAs guide RISC to bind to complementary sequences on target mRNA molecules. Once bound, RISC either degrades the mRNA or blocks its translation, effectively silencing the gene encoded by that mRNA.

Key Concept:Gene Therapy Basics

b) To correct genetic defects
[Solution Description]
Gene therapy aims to correct genetic defects by introducing, altering, or removing genes within an individual’s cells and biological tissues. This treatment approach targets the underlying cause of genetic disorders rather than just addressing symptoms.

Key Concept:Somatic Hybridization, Ethical Concerns

b) It could threaten genetic diversity and ecosystem balance.
[Solution Description] Somatic hybridization involves fusing protoplasts from different plant species or varieties to create new hybrids with desired traits such as disease resistance. While this technique offers significant agricultural benefits, it raises ethical concerns about biodiversity and ecological balance. Introducing hybrids into natural ecosystems may disrupt local species’ genetic integrity. Additionally, there are concerns about patenting life forms and ensuring equitable access to technology and resources, particularly for farmers in developing countries.

– Somatic hybrids can alter native biodiversity.
– Potential for negative impact on ecosystem balance.
– Issues with patenting and access to technology.

Key Concept:Identification

c) GEAC
[Solution Description] In India, the Genetic Engineering Approval Committee (GEAC) is the authority responsible for evaluating the validity and safety of GM research.

Key Concept: Genetically Engineered Insulin

c) Reduced chances of allergic reactions

[Solution Description] Genetically engineered insulin has a structure identical to human insulin and hence does not cause allergic reactions, unlike some cases of animal insulin.

Key Concept:Real-world Application, Advanced Conceptual Understanding

c) Crop rotation integrated with cover cropping
[Solution Description] In regions prone to drought, maintaining soil moisture and health is crucial. Crop rotation and cover cropping are beneficial as they improve soil structure and enhance its ability to retain water. Cover crops, specifically, increase organic matter, reduce erosion, and conserve soil moisture. While composting also improves soil quality, it doesn’t specifically address water retention like cover cropping does. Therefore, adopting crop rotation along with cover cropping offers a dual benefit: it sustains biodiversity and mitigates water scarcity by improving soil’s water-holding capacity.

Key Concept: RNAi Mechanism

a) RNA interference

[Solution Description] RNA interference (RNAi) is the biological process in which RNA molecules inhibit gene expression or translation by neutralizing targeted mRNA molecules, typically using double-stranded RNA (dsRNA).

Key Concept:RNA Interference

b) It silences specific mRNA related to pest survival, thus preventing their growth.
[Solution Description] RNA interference (RNAi) is a biological process where RNA molecules inhibit gene expression or translation, effectively silencing targeted mRNA. In genetically modified plants, this mechanism is used to silence specific genes essential for pest survival, thereby providing resistance to pests without harming the plant itself.

Key Concept:Patent Example

c) Basmati rice
[Solution Description] Basmati rice is given as an example in the syllabus as a bio-resource that has been patented, highlighting issues surrounding patents and traditional knowledge.

Key Concept:Basic Concept

b) Unpredictable ecological impact
[Solution Description] One major concern associated with the introduction of genetically modified organisms is their unpredictable ecological impact, which can affect biodiversity and ecosystem functions.

Key Concept:Historical Context

b) 1997
[Solution Description] The Basmati rice patent controversy involved a U.S. patent granted in 1997 to RiceTec Inc., which claimed certain varieties of Basmati rice grown outside India and Pakistan.

Key Concept:Real-world Application

c) Golden rice
[Solution Description] Golden rice is a genetically modified organism that has been developed to enhance its nutritional value by being enriched with beta-carotene, a precursor of Vitamin A. This modification aims to address Vitamin A deficiencies in regions where rice is a staple food but lacks essential nutrients. The genetic alteration involves introducing genes responsible for the biosynthesis of beta-carotene into the rice genome, enabling it to produce this nutrient naturally.

Key Concept:Basic Definition

a) Unauthorized use of bio-resources
[Solution Description] Biopiracy refers to the unauthorized and unethical appropriation or commercial exploitation of biological resources, often without compensating the indigenous people or countries where these resources originate.

Key Concept:Definition Recall

b) Animals with altered DNA to express a foreign gene
[Solution Description] Transgenic animals are those that have had their DNA manipulated to possess and express an extra (foreign) gene.

Key Concept:Insulin Source

c) Bacteria
[Solution Description] Human insulin is produced using recombinant DNA technology by inserting the insulin gene into bacteria such as {E. coli}. This bacterium then produces insulin that can be harvested and purified.

Key Concept:Basic Principle

b) Antigen-antibody interaction
[Solution Description] ELISA is primarily based on the interaction between antigens and antibodies, which allows the detection of specific proteins or antibodies in a sample.

Key Concept:Basic Definition

c) To study normal physiology and development
[Solution Description] Transgenic animals are primarily used to study normal physiology and development by altering gene expression, as well as serving as models for human diseases.

Key Concept:Somatic Hybridization

a) Pomato
[Solution Description] Somatic hybridization involves the fusion of protoplasts from two different plant species to combine desirable traits into one organism. In the case of potato and tomato, this process results in a hybrid plant often referred to as “Pomato,” which combines attributes such as tuber production from potatoes and fruit-bearing characteristics from tomatoes.

Key Concept:Genetic Modification Process

d) To enhance Vitamin A content
[Solution Description] The genetic modification process in crops like Golden Rice aims primarily at enhancing their nutritional content. Specifically, Golden Rice is genetically modified to produce beta-carotene, a precursor of Vitamin A, to help combat deficiency of this nutrient in human diets.