NCERT Solutions for Class 12 Biology Chapter 12 - Biotechnology and its Applications

NCERT Solutions for Class 12 Biology Chapter 12, Biotechnology and Its Applications, delve into the transformative field of biotechnology, which harnesses biological processes for various practical applications. This chapter explores how biotechnology plays a vital role in sectors such as agriculture, medicine, and environmental management. Students will discover key concepts like genetic engineering, recombinant DNA technology, and cloning, which are pivotal in developing genetically modified organisms (GMOs) and therapeutic products.

The chapter emphasizes the potential of biotechnology in enhancing crop yields, producing life-saving medications, and addressing environmental challenges through bioremediation. Understanding these applications is crucial for students preparing for competitive exams like NEET, as it lays a solid foundation for advanced studies in biology and its real-world implications.

These solutions, provided by Aakash, are designed to help students grasp the essential topics within biotechnology, offering detailed explanations and answers that facilitate effective exam preparation. Additionally, the content highlights the importance of biotechnology in improving human health and sustainable practices, ensuring students appreciate its significance in today’s world.

Q1. 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
Answer:
(c)Toxin is inactive
-The Bt toxin remains inactive in the bacteria. It gets activated after entering the insect gut due to the alkaline pH.

Q2. What are transgenic bacteria ? Illustrate using any one example.
Answer:
Transgenic bacteria are the bacteria whose genes have been manipulated by transferring foreign genes into its genome through recombinant DNA technology. For example, transgenic E.coli was developed by introducing in it, two DNA sequences of A and B chains of human insulin in order to produce insulin to treat diabetic patients.


Q3. Compare and contrast the advantages and disadvantages of production of genetically modified crops.
Answer:
GM crops are genetically modified crops that can be made by transferring desirable characteristics in them. The main advantage of GM crops is that they are highly productive and they yield an increased amount of produce. The other advantages of the production of genetically modified crops in order to increase the yield are as follows:
1.GM crops can be developed for increasing the nutritional quality of crop products. For example golden rice with enhanced vitamin A content is a GM crop.
2.Many GM crops are developed to have insect pest resistance, thus decreasing our dependence on chemical-based insecticides/pesticides.
3.GM crops are made to be highly tolerant of environmental conditions.
4.GM crops are highly tolerant to abiotic conditions
5.GM Crops minimize post- harvesting losses.

GM crops possess some disadvantages also. The presence of a transgene in commercial crops endangered wild species. The gene for Bt toxin expressed in pollen endangers pollinators such as honeybees. These crops supply allergens and transfer antibiotic resistance markers. They are damaging to the genetic environment.


Q4. What are Cry proteins? Name an organism that produces it. How has man exploited this protein to his benefit?
Answer:
Cry proteins are toxin proteins encoded by cry genes. These are produced by a bacteria called Bacillus thuringiensis which itself remains safe from cry toxins by having methylated DNA. Cry proteins act as insecticides as they are toxic to insects. This property of Cry proteins has been exploited in producing genetically modified crops such as Bt cotton, Bt brinjal etc. These crops are resistant to insects of order Lepidoptera.

Q5. What is gene therapy? Illustrate using the example of adenosine deaminase (ADA) deficiency.
Answer:
Gene therapy refers to a collection of methods and technologies allowing correction or replacement of a defective or dysfunctional gene. While correcting, a normal gene is transferred into the individual's embryo to replace and perform the function of the original defective gene. One well-established example of gene therapy is ADA deficiency. This is caused by the deletion of a gene encoding for enzyme adenosine deaminase. The gene therapy for ADA deficiency was carried out in a 4-year-old patient by the following method:
1.The lymphocytes of patients were grown in a culture in vitro.
2.A functional ADA cDNA was introduced in these lymphocytes using a retroviral vector.
3.The transformed lymphocytes were introduced back into the blood of the patient.
4.The patient is regularly infused with transformed lymphocytes
5. For a permanent cure of ADA deficiency, a gene isolated from bone marrow cells is introduced in the patient in the early stage


Q6. Diagrammatically represent the experimental steps in cloning and expressing a human gene (say the gene for growth hormone) into a bacterium like E. coli?
Answer:
Diagrammatic representation of steps in DNA cloning

Q7. Can you suggest a method to remove oil (hydrocarbon) from seeds based on your understanding of rDNA technology and chemistry of oil?
Answer:
Recombinant DNA technology is a technique by which the genome of an organism can be manipulated Oils are made of glycerols and fatty acids. So using recombinant DNA technology we can silence the genes coding for glycerol and fatty acids and remove oil (hydrocarbon) from seeds.


Q8. Find out from the internet what golden rice is.
Answer:
Golden rice is a variety of rice crop, genetically engineered to synthesise beta carotene which is a precursor of vitamin A. The normal rice produces be a carotene but in leaves, to increase the production of vitamin A, beta carotene should be synthesised in the endosperm. Golden rice was developed by transferring two beta-carotene biosynthesis genes into the rice genome. These genes include psy (phytoene synthase) from a plant named Narcissus pseudonarcissus (daffodil) and crtI(phytoene desaturase) from the soil bacterium Erwinia uredovora. These genes were under endosperm-specific promoter so that they will show expression in the endosperm.

Q9. Does our blood have proteases and nucleases?
Answer:
Proteases and nucleases are two enzymes that catalyse the hydrolysis of proteins and nucleic acids respectively. These enzymes are not found in blood, instead, blood contains protease inhibitors protecting the proteins being broken down. Similarly, nucleases are also absent in blood.


Q10. Consult the internet and find out how to make orally active protein pharmaceutical. What is the major problem to be encountered?
Answer:
Orally active protein pharmaceuticals contain Biologically Active Proteins,lipids etc. These are taken into the body by oral route in various formulations. The production of these protein pharmaceuticals involve encapsulation of proteins or peptides in liposomes using penetration enhancers. These proteins or peptides are used for the treatment of diseases and they can also be used as vaccines. The major problem encountered in the administration of the pharmaceuticals is that they are ingested orally, and digested by the proteases present in the stomach before showing results. This is why such pharmaceuticals are directly ingested into the target site.

Biotechnology and Its Applications Important Questions

Q1. Where can I find Biotechnology and Its Applications PDF notes for NCERT Class 12 Biology?
Answer: You can find Biotechnology and Its Applications PDF notes on various educational websites, online learning platforms, and forums dedicated to NCERT Class 12 Biology. Platforms often provide downloadable notes and summaries that aid students in their studies.

Q2. How can NCERT Class 12 Biology notes help with understanding Biotechnology and Its Applications?
Answer: NCERT Class 12 Biology notes provide clear explanations of key concepts related to Biotechnology and Its Applications. They summarize essential topics, include diagrams for visual learning, and present important definitions and processes, making it easier for students to grasp the material and prepare effectively for exams.

Q3. What are the best study resources for Biotechnology and Its Applications in NCERT Class 12 Biology?
Answer: The best study resources include NCERT textbooks, online video lectures, interactive quizzes, and previous years' question papers. Additionally, reference books and study guides focusing on Biotechnology can provide further insights and practice questions.

Q4. What is the significance of Biotechnology and Its Applications in the NCERT Class 12 Biology curriculum?
Answer: Biotechnology and Its Applications is a significant part of the NCERT Class 12 Biology curriculum because it equips students with knowledge about advanced biotechnological techniques and their real-world applications. Understanding this topic is essential for fostering awareness of how biotechnology can address challenges in health, agriculture, and environmental sustainability.