Biotechnology and its applications ncert solutions: Class 12th biology chapter 10 ncert solutions
| Textbook | NCERT |
| Class | Class 12 |
| Subject | Biology |
| Chapter | Chapter 10 |
| Chapter Name | Biotechnology and its applications class 12 ncert solutions |
| Category | Ncert Solutions |
| Medium | English |
Are you looking for Ncert Solutions for Class 12 Biology Chapter 10 Biotechnology and its applications? Now you can download Ncert class 12 biology chapter 10 questions and answers pdf from here.
Question 1: Which part of the plant is best suited for making virus-free plants and why?
Solution 1: The best part of a plant for making virus-free plants is the meristem tissue, particularly the apical meristem. Meristematic cells are undifferentiated and located at the tips of roots and shoots, where active growth occurs. This region is ideal for producing virus-free plants because it typically remains free from systemic infections, including viruses.
Viruses spread more slowly in the apical meristem due to its high rate of cell division and lack of vascular tissue, which limits the virus’s movement. By culturing meristem tissue, scientists can regenerate whole plants through tissue culture techniques that are free of viral contamination, ensuring healthier and more productive crops.
Question 2: What is the major advantage of producing plants by micropropagation?
Solution 2: The major advantage of producing plants by micropropagation is the ability to generate large numbers of genetically identical, disease-free plants in a relatively short period of time. This technique allows for the rapid multiplication of plants, even from a small amount of starting material, making it highly efficient for commercial propagation of crops, ornamental plants, and endangered species.
Since micropropagation occurs in a controlled, sterile environment, plants produced are often free from pests, diseases, and environmental stressors. Additionally, micropropagation ensures uniformity in traits such as growth rate, fruit quality, and yield, which is particularly beneficial for maintaining consistency in agriculture and horticulture.
Question 3: Find out what the various components of the medium used for propagation of an explant in vitro are?
Solution 3: The medium used for the in vitro propagation of an explant, such as in tissue culture, is typically a complex mixture of nutrients and hormones designed to support plant growth and development. The key components of this medium include:
- Mineral salts (macronutrients and micronutrients) – for essential plant nutrition.
- Vitamins – to support growth, such as thiamine, nicotinic acid, and pyridoxine.
- Carbon source (sugar e.g., sucrose) – as a carbon source for energy is added as an energy source since the plant tissues in vitro do not photosynthesize efficiently..
- Agar or other gelling agents – to solidify the medium.
- Growth regulators – like auxins (for root development) and cytokinins (for shoot growth).
- Organic supplements – like amino acids, coconut milk, or casein hydrolysate, sometimes used to enhance growth.
- Water – purified to dissolve all the components and create a suitable growth environment.
- pH adjusters: The medium’s pH is typically adjusted to around 5.6–5.8 for optimal nutrient availability and plant growth.
Question 4: 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
Solution 4: (c) the toxin is inactive.
In bacteria, the toxin is present in an inactive form, called prototoxin, which gets converted into active form when it enters the body of an insect.
Question 5: What are transgenic bacteria? Illustrate using any one example.
Solution 5: Transgenic bacteria contain foreign gene that is intentionally introduced into its genome. They are manipulated to express the desirable gene for the production of various commercially important products.
An example of transgenic bacteria is E.coli. In the plasmid of E.coli, the two DNA sequences corresponding to A and B chain of human insulin are inserted, so as to produce the respective human insulin chains. Hence, after the insertion of insulin gene into the bacterium, it becomes transgenic and starts producing chains of human insulin. after that, these chains are extracted from E.coli and combined to form human insulin.
Question 6: Compare and contrast the advantages and disadvantages of production of genetically modified crops.
Solution 6: Genetically modified (GM) crops have sparked significant debate due to their potential advantages and disadvantages. Here’s a comparison:
Advantages of GM Crops:
Increased Yield: GM crops are often engineered for higher productivity, allowing farmers to produce more food on the same amount of land.
Pest and Disease Resistance: Many GM crops are designed to be resistant to pests, diseases, and herbicides, reducing the need for chemical pesticides and minimizing crop losses.
Drought and Stress Tolerance: Some GM crops are modified to withstand harsh environmental conditions, such as drought, extreme temperatures, or poor soil, helping maintain yields in unfavorable conditions.
Improved Nutritional Value: Certain GM crops, like “Golden Rice,” are enriched with nutrients (e.g., vitamin A) to address nutritional deficiencies in populations that rely on a limited diet.
Reduced Environmental Impact: By decreasing the need for chemical inputs like pesticides and fertilizers, GM crops can lead to more sustainable farming practices and less environmental degradation.
Disadvantages of GM Crops:
Environmental Risks: GM crops may potentially harm non-target organisms, lead to the development of resistant pests or weeds (superweeds), and disrupt ecosystems through gene flow to wild relatives.
Health Concerns: Although studies show GM crops are safe for consumption, some people fear potential long-term health effects, such as allergenicity or unintended effects of gene transfer.
Loss of Biodiversity: The widespread use of a few genetically modified varieties could reduce genetic diversity in crops, making the agricultural system more vulnerable to diseases or environmental changes.
Economic Issues: GM seeds are often patented by biotech companies, making them expensive for small-scale farmers. This can lead to dependency on multinational corporations for seeds and limit farmers’ traditional practices like seed-saving.
Ethical and Social Concerns: There is ongoing ethical debate about the manipulation of nature and the potential for socioeconomic inequalities, especially for smallholders who may not benefit equally from the technology.
Question 7: What are Cry proteins? Name an organism that produce it. How has man exploited this protein to his benefit?
Solution 7: The bacterium Bacillus thuringiensis is a common soil bacterium which produces a protein toxin that kills certain insects. The toxin is a crystal (Cry) protein. There are several kinds of Cry proteins which are toxic to different groups of insects. The gene encoding Cry protein is called cry gene.
Biotechnologists have been able to isolate the gene responsible for production of toxin and to introduce it into a number of plants to produce genetically modified plants resistant to insects, e.g., Bt cotton (resistant to bollworm) and GM tobacco (resistant to hornworms).
Question 8: What is gene therapy? Illustrate using the example of adenosine deaminase (ADA) deficiency.
Solution 8: The process of correction of malfunctioned genes, either by inserting the desirable gene or repairing or manipulating them, is referred to as gene therapy. It is a collection of methods which enables the correction of a gene defect. In this therapy, the gene is inserted into the cells and tissues of a person to treat a disease.
Adenosine deaminase deficiency (ADA) is a rare genetic disorder caused due to deletion of the gene for adenosine deaminase. This enzyme is critical for the normal functioning of the immune system. This disorder can be treated by gene therapy, wherein the gene is transfected into early embryonic cells of the bone marrow for permanent utilization.
Question 9: Digrammatically represent the experimental steps in cloning and expressing an human gene (say the gene for growth hormone) into a bacterium like E. coli ?
Solution 9: DNA cloning is a method of producing multiple identical copies of specific template DNA. It involves the use of a vector to carry the specific foreign DNA fragment into the host cell. The mechanism of cloning and transfer of gene for growth hormone into E.coli is represented below.
Question 10: Can you suggest a method to remove oil (hydrocarbon) from seeds based on your understanding of rDNA technology and chemistry of oil?
Solution 10: A method to remove oil (hydrocarbon) from seeds using rDNA technology could involve genetically modifying the seeds to express enzymes that break down oil molecules. Specifically, enzymes like lipases can be engineered to hydrolyze the triglycerides in oils into fatty acids and glycerol. By introducing a gene for lipase production into the seed, these enzymes can be activated during processing, effectively breaking down the oil. This approach, combined with traditional extraction methods like pressing or solvent extraction, could enhance the efficiency of oil removal from seeds.
Question 11: Find out from internet what is golden rice.
Solution 11: Golden Rice is a genetically modified variety of rice (Oryza sativa), developed to address vitamin A deficiency in regions where this nutrient is lacking in the diet. It has been engineered to produce beta-carotene, a precursor to vitamin A, in the rice grain’s endosperm. Normally, rice plants produce beta-carotene in their leaves, where it plays a role in photosynthesis, but not in the edible part of the grain, since photosynthesis doesn’t occur there. By introducing beta-carotene into the endosperm, Golden Rice offers a more accessible and cost-effective solution compared to vitamin A supplements.
The introduction of this genetically engineered rice has been met with controversy and opposition from environmental activists, leading to regulatory delays and limited availability for human consumption.
Question 12: Does our blood have proteases and nucleases?
Solution 12: No, blood does not have proteases and nucleases. But some proteases do exist in their inactive form. If it would have been found in blood and cells, it would have been digested.
Question 13: Consult internet and find out how to make orally active protein pharmaceutical. What is the major problem to be encountered?
Solution 13: Orally active protein product that is successfully manufactured is vaccines for preventions of infectious diseases such as hepatitis B, herpes, influenza, etc. Gene for antigen are isolated from bacteria and grown along with cut leaf portions of potato plant in antibiotic medium – followed by callus formation and recombinant/transgenic potato are obtained which contain those vaccines.