Cbse Class 12 Biology Revision Notes Chapter 12

Class 12 Biology Chapter 12 Notes: Biotechnology And Its Applications

The word Biology is derived from the Greek word ‘bio’, meaning life and ‘logos’, meaning study. Biology is defined as the science of life and consists of bacteria, animals, plants and fungi.

Biotechnology is a field of Biology that fundamentally deals with the large-scale production of biopharmaceuticals using genetically modified organisms. Biotechnology applications include diagnostics, genetically modified plants for agriculture, waste treatment, and energy production. 

Extramarks is one of the leading  platforms known and trusted for providing high-quality study materials for Class 11 to Class 12. Our team of academic subject experts have created study materials based on the latest CBSE syllabus and NCERT guidelines. Students can confidently rely on our comprehensive study solutions.

Extramarks Class 12 Biology Chapter 12 Notes covers topics of Genetically Modified Organisms developed from techniques such as  recombinant DNA technology. Also, students aspiring for careers in biotechnology or paramedical sciences can refer to Class 12 Biology Chapter 12 Notes to get an in-depth understanding of this subject.

Key Topics Covered in Class 12 Biology Chapter 12 Notes

Introduction:

Biotechnology deals with the industrial-scale production of biopharmaceuticals and genetically modified organisms. There are three critical research areas in biotechnology mentioned in Chapter 12 Biology Class 12 Notes.

1. Provision of the best catalyst in the form of an enhanced organism, usually a pure enzyme or microbe.
2. Creating optimal conditions through engineering for the action of a catalyst.
3. Downstream processing technology to purify the organic compound

Applications of Biotechnology in Agriculture:

Few applications of biotechnology in the farming industry as covered in our Class 12 Biology Chapter 12 Notes are given below:

• To enhance food production, we can look at three options; agrochemical based agriculture, organic agriculture and genetically engineered crop-based agriculture.
• Despite the green revolution, increased yields are insufficient to feed the growing human population.
• Moreover, better management practices and agrochemicals are often expensive to the farmers.
• Hence the use of genetically modified crops was the only possible solution.
• Genetically modified organisms are plants, animals, bacteria and fungi whose genes have been altered by manipulation.

Here are some benefits of genetic modification in plants:

1. It has made crops more tolerant of abiotic stresses.
2. It has reduced dependence on chemical pesticides.
3. It has led to the reduction of post-harvest losses.
4. It has helped to increase the efficiency of plants in using minerals.
5. It has improved the nutritional quality of food such as vitamin A enriched rice.
6. Genetically modified plants also help supply various resources to industries in the form of fuels and pharmaceuticals.

The benefits of genetically modified plants are covered in more detail in our Class 12 Biology Chapter 12 Notes. These notes are prepared by experienced faculty and have proven beneficial to lakhs of students who have already registered with Extramarks learning platform. Students can bank on these solutions not only for last-minute revision tests and exams, but also for clearing NEET, and other medical exams.

The use of Bacillus thuringiensis:

The bacteria Bacillus thuringiensis produces Bt toxin.  This  gene has been cloned from bacteria where it is expressed in plants to provide resistance to pests and insects. Due to the creation of biopesticides, the need for insecticides is prevented. Examples are Bt cotton, Bt tomato, soybean, potato, etc.

Bt Cotton:

• Few strains of Bacillus thuringiensis produce proteins that kill certain insects such as tobacco budworm, beetles, mosquitoes and flies.
• The inactive proteins, once ingested by the insect, are activated.
• Due to the alkaline pH in the insect’s gut, the activated toxin binds to the epithelial cells and creates pores.
• This causes cell swelling and lysis that kills the insect.
• The selection of genes depends upon the crop and targeted pest. 
• The toxin is coded by a gene named cry; for example, cryIAc and cryIIAb control Cotton bollworms and cryIAb control corn borers.

Pest Resistant plants:

• Meloidogyne incognita, a nematode parasite, infects the roots of tobacco plants and decreases their yield.
• A strategy called RNA interference was adopted to prevent this infestation.
• RNAi is a method that involves the silencing of a specific mRNA. 
• dsRNA molecule binds and prevents the translation of mRNA.
• Agrobacterium vectors introduced DNA that produces both sense and antisense RNA in host cells.
• The two RNAs being complementary to each other formed a double standard DNA that began the RNA interference and silenced the specific mRNA of the nematode.
• The parasite could not survive in a transgenic host expressing interfering RNA. Hence the plant was protected from the parasite.

Biotechnological Applications In Medicine:

Recombinant DNA technology enables the mass production of effective therapeutic drugs. Recombinant therapeutics prevent unwanted immunological responses. Today, there are about 30 recombinant therapeutics globally, while 12 of these are being marketed in India. The fast pace advancement happening in medicine due to various Biotechnology applications will change the overall pharmaceutical industry. All students pursuing science, medical, biotech and similar streams are recommended to pay special attention to this development. They can refer to Extramarks Class 12 Biology Chapter 12 Notes where our experts have covered this topic at length. 

Genetically Engineered Insulin:

• Earlier insulin used in the management of adult-onset diabetes was extracted from the pancreas of slaughtered cattle and pigs. However, this caused a few patients to develop allergies and other reactions.
• Insulin consists of two short polypeptide chains: chains A and B, linked by disulphide bridges.
• In mammals, insulin is synthesised by a prohormone which contains an extra stretch called the C peptide.
• C peptide is absent in mature insulin and separated during maturation into insulin.
• In 1983, Eli Lilly, an American scientist, formed two DNA sequences corresponding to human insulin’s A and b chains. This was introduced in the plasmids of E.coli to produce insulin chains.
• The chains A and B were then extracted and combined to form human insulin.

Gene therapy:

• Gene therapy is a corrective therapy applied to people with a hereditary disease where there is a correction of a gene defect that has been diagnosed in a child.
• The correction involves the delivery of a normal gene into the individual to compensate for the non-functional gene.
• Adenosine deaminase(ADA) deficiency was the first clinical gene therapy for a four-year-old girl in 1990. This enzyme is vital for the function of the immune system.
• In some cases, ADA deficiency can be cured by bone marrow transplantation. While in others, enzyme replacement therapy is performed on the patient by injecting the functional area.
• The first step toward gene therapy involves the extraction of Lymphocytes from the patient’s blood and growing in a culture outside the body.
• A functional ADA cDNA is introduced into these lymphocytes and returned to the patient. Regardless, the cells require a periodic infusion of genetically engineered lymphocytes.
• In an embryo, when the ADA was introduced to isolated genes from the bone marrow cells, it could be a permanent cure.

Apart from Class 12 Biology Chapter 12 Notes, students can also visit the Extramarks website for more study resources such as NCERT Solutions, CBSE Sample Papers, CBSE Revision Notes, etc. to step up their preparation.

Molecular Diagnosis:

• For effective treatment, early diagnosis is crucial. Techniques like recombinant DNA technology, Polymerase Chain Reaction(PCR) and Enzyme-Linked Immuno-Sorbent Assay(ELISA) are used for early diagnosis. In any disease, the presence of a pathogen is usually suspected when a disease produces symptoms. One can only detect the symptom when the concentration of the pathogen is very high.

• PCR is a method used:

1. To detect a low concentration of a bacteria or virus by amplifying the nucleic acid.
2. To detect HIV in patients.
3. To check mutations in genes of Cancer patients.
4. To identify genetic disorders.

• A single-stranded DNA or RNA is tagged with a radioactive molecule which is then allowed to hybridise with its complementary DNA. The clone cells are detected with the help of autoradiography, where the clone with the mutated gene will not appear on the photographic film. The foundation for the technique of ELISA is antigen-antibody interaction.

Transgenic Animals:

Transgenic animals are animals whose DNA is altered by manipulation to express a foreign gene. Class 12 Biology Chapter 12 Notes highlight some common reasons for introducing transgenic animals.

• Normal physiology and development:

Transgenic animals are specifically designed to study the regulation of genes and how it affects normal function. For instance, the study of insulin-like growth factors. The introduction of genes from other species alters the formation of this factor. The insulin-like growth factor helps study the biological role of the factor   in  the body.

• Study of Disease:

Transgenic animals help us understand the contribution of genes to the development of diseases. These are made to serve as models for human diseases to investigate new treatments as seen in cancer, cystic fibrosis, rheumatoid arthritis and Alzheimer’s. .

• Biological products:

Transgenic animals are used to create biological products by introducing a portion of Genes coding for a particular product. For instance, human proteins treat diseases such as emphysema, phenylketonuria and cystic fibrosis. The first transgenic cow, named Rosy, was introduced in 1997. The cow produced protein-enriched milk that contained Alpha-lactalbumin and served as a more balanced product for human babies.

• Safety of vaccines:

Before humans use vaccines, they are tested on transgenic mice for safety. They are being used to test the safety of the polio vaccine. 

• Chemical safety testing:

Chemical safety testing is also termed toxicity testing or safety testing. Transgenic animals carry genes that are more sensitive to toxins than non-transgenic animals.  Toxicity tests in  animals are used to obtain results in less time.

Ethical Issues:

• Ethical standards are required to evaluate all human activities.
• GEAC(Genetic Engineering Approval Committee), introduced by the Indian government, makes decisions regarding the validity of GM research and the safety of the introduction of GM organisms for public services.
• There are 2 lakh varieties of rice in India. Twenty-seven types of basmati are grown in the country.
• In 1997, patent rights were granted to an American company on basmati rice.
• This permitted the company to sell a new variety of basmati in the US and abroad. Indian farmers’ varieties developed a new variety. However, the Indian basmati was crossed with semi-dwarf varieties and was claimed as an invention.
• If these patent applications are not counted immediately, other countries will encash on our legacy.

What is biopiracy?

As explained in our Class 12 Biology Chapter 12 Notes, the use of bioresources by multinational companies and other organisations without authorisation from countries and compensatory payment from the people concerned is termed biopiracy. 

Most industrial Nations tend to exploit traditional knowledge to develop modern applications and the same time, effort and expenditure for commercial purposes. Some nations are now developing loss to prevent unauthorised exploitation of bioresources and traditional knowledge. The parliament of India has recently cleared the second amendment of the Indian patent bill. It takes into consideration the patent terms, emergency provision and development initiative.

Students get detailed and authentic study material   in our Class 12 Biology Chapter 12 Notes. These study notes are prepared by subject matter experts at Extramarks,  after  thorough research and analysis to help students achieve their study goals without much hassle and even get to clarify their doubts to master the topic. . 

Class 12 Biology Chapter 12 Exercise Questions and Answer Solutions

Extramarks is one of the leading websites for board exam preparation. Our subject experts have included a lot of exercise questions and answers in our Class 12 Biology Chapter 12 Notes. To get good grades in Biology, one needs to get the hang of the chapter and even practise answer writing skills to stay ahead in the competition.  The answers should briefly cover all essential points. This regular habit of solving questions will definitely enhance the confidence in achieving high marks in the final exams.

Students can click on the links provided below to access the solutions for various Exercises they will need to prepare for the examination.

• Chapter 12: Exercise 12.1 – Question and Answers 

Extramarks website provides excellent solutions for every exercise question. The solutions include a detailed explanation of topics covered in biotechnology and its applications, pointwise in a systematic and organised manner. You can click on the respective links to view Class 12 Biology Exercise and Answer Solutions.

Apart from Biology Chapter 12 Class 12 Notes, Students can visit the Extramarks website for more information by clicking on the links given below:

• CBSE Revision Notes
• CBSE Sample Papers
• CBSE Previous Year Question Papers
• CBSE additional questions 
• Essential Formulas

NCERT Exemplar for Class 12 Biology Chapter 12 Notes

NCERT Exemplar books are available along with the NCERT Textbooks. The role of Exemplar is to be the extended Q&A study guide along with the textbook. The Exemplar book is a collection of a variety of questions for students to practice and to develop a strong conceptual clarity.    . . Students will get to practise a variety of questions covered in Exemplars – MCQs, short answer questions, long format questions, etc. 

While solving the questions from Exemplar, students will also get to revise key topics. . They will  get to know their grey areas and begin to work on them at an early stage to avoid any last minute hassle. Students can  clarify  their doubts and be more confident ahead of the exams.

Students can first study the chapter from the NCERT textbook and then refer to our Class 12 Biology Chapter 12 Notes. Then they can solve questions given in NCERT Exemplar. This way students will have a comprehensive understanding of the Biotechnology chapter. Our study notes also contain solutions for all the questions covered in NCERT Textbook and NCERT Exemplar books.

Key Features of Class 12 Biology Chapter 12 Notes

Let’s look at some essential features of Class 12 Biology Chapter 12 Notes:

• Extramarks is one of the leading websites that provides students with authentic and reliable study materials.
• The Notes are prepared based on the latest CBSE syllabus and follows the NCERT guidelines.
• These are prepared by Extramarks professionals in the field of Biology and Biotechnology.
• Class 12 Biology Chapter 12 Notes are designed for students to understand the information in a more simple language with the use of visual diagrams and real-life applications.
• All lengthy concepts and complicated definitions are prepared in a pointwise manner for the students.
• Extramarks website provides a platform for students to revise and prepare for their board examination and NEET through their comprehensive Notes and solutions.