NCERT Solutions Class 12 Biology Chapter 12

NCERT Solutions Class 12 Biology Chapter 12

Biology is that branch of science which is concerned with studying living things and their processes. The word biology is sometimes substituted by the terms life sciences or biological sciences due to its vast scope and multidisciplinary nature. Structure, function, growth, evolution, distribution, identification, and taxonomy are all topics studied by biologists. The word biology is based upon the Greek words “bios,” which means “life,” and “logos,” which means “knowledge” or “learning.”

The 12th chapter of Class 12 Biology is Biotechnology and its Applications. Biotechnology and its Applications (Chapter 12) discusses how biotechnology enhances our daily lives and the implication of biotechnology. This chapter includes biotechnology applications such as diagnostics, therapeutics, agricultural genetically modified crops, waste treatment, energy generation, bioremediation, and processed food. In addition, biotechnical applications in Medicine and Agriculture, Ethical Issues, Transgenic Animals, and other topics are covered.

Biology is very popular amongst students, and it includes many theoretical topics. Unfortunately, most students struggle to remember key terms and frequently fail to comprehend various critical life processes. Chapters like Evolution, Genetics, and Biotechnology, for example, include a variety of concepts that many students find difficult to grasp. Thus, they choose to skip them. But not anymore; Extramarks has developed detailed NCERT Solutions Class 12 Biology Chapter 12. Subject matter specialists have developed these.

Extramarks offers students a variety of study materials to choose from. In addition, they can access several study materials for all classes. Material such as NCERT books, CBSE revision notes, CBSE sample papers, CBSE previous year question papers, and more are waiting for them at the Extramarks website.

Key Topics Covered in NCERT Solutions Class 12 Biology Chapter 12

Mentioned below are the key concepts covered in NCERT Solutions Class 12 Biology Chapter 12- Biotechnology and its Applications:

Introduction to Biotechnology
Applications of Biotechnology
Applications of Biotechnology in Agriculture
Application of Biotechnology in Medicine
Transgenic Animals
Applications in Aquaculture
Production of Antibiotics

Let us now look at Extramarks’ in-depth information on each subtopic in NCERT Solutions Class 12 Biology Chapter 12- Biotechnology and its Applications.

Introduction to Biotechnology

NCERT Solutions Class 12 Biology Chapter 12 explains Biotechnology as a vast field of biology that uses both the technology and the application of live organisms and their components to develop, alter, and generate useful products for human wellbeing. Karoly Ereky, an agricultural engineer, created the phrase “biotechnology” in 1919, earning him the title of “Father of Biotechnology.”

Applications of Biotechnology

Biotechnology is widely employed in various fields to modify and generate products that are beneficial to humans. NCERT Solutions Class 12 Biology Chapter 12 states some of the applications highlighted below:

Applications of Biotechnology in Agriculture

Agriculture uses biotechnology in a variety of ways. For example, agrochemicals, organic agriculture, and genetically modified crop-based agriculture can benefit.

It can be used to create genetically engineered creatures. GMOs are genetically modified organisms (GMOs) that have had their genetic material altered.

NCERT Solutions Class 12 Biology Chapter 12 explains the use of genetically engineered organisms in different ways-

  • Crops are resistant to abiotic conditions such as heat, cold, and other extremes.
  • Pest-resistant crops
  • Assist in the reduction of post-harvest losses.
  • Plants can efficiently use minerals.
  • Food that has higher nutritional value.

The most important use of biotechnology is the creation of pest-resistant plants. For example, bacillus thuringiensis is a bacterium that generates an insecticidal toxin called Bt toxin. A gene coding for Bt toxin can be extracted and introduced into the plant to give insect or pest resistance.

Bt Cotton

NCERT Solutions Class 12 Biology Chapter 12 explains that Bacillus thuringiensis generates proteins that can kill lepidopterans, coleopterans, and dipterans, among other insects. In addition, they generate insecticidal protein, which becomes active once it enters the insect’s body. When this toxin attaches to the midgut, it causes cells to expand, leading to the insect’s death. Cotton plants are injected with Bt genes that have been extracted. Bt cotton is the name given to this kind of cotton.

Pest resistant plants

  • Various pests attack the plants, causing loss and a reduction in the plant’s output.
  • Meloidogyne incognita, a nematode that infects the roots of tobacco plants, reduces the plant’s output. RNA interference technology was utilised to prevent this. This approach includes using a complementary dsRNA molecule to silence a particular mRNA. This prevents the mRNA from being translated.

Application of Biotechnology in Medicine

Biotechnology has made a commendable contribution to the medical field. Medicinal biotechnology is the application of biotechnology in medicine.

They describe how to make humulin, which is a genetically modified insulin. Humulin is highly beneficial in treating a significant number of diabetic individuals. Insulin was previously taken from the pancreas of slaughtered animals like cows and pigs. In humans, such insulin has the potential to trigger allergies. The generation of mature and assembled insulin is the key thing for insulin manufacturing.

Gene therapy

  • Gene therapy is used to treat disorders caused by genetics. Gene therapy is the process of correcting genetic abnormalities.
  • A normal gene is injected into a human or an embryo to replace the defective gene in gene therapy.
  • In 1990, a 4-year-old child with Adenosine deaminase deficiency received the first gene therapy. Previously, bone marrow transplantation and enzyme replacement treatment were used to treat this deficient illness. However, neither strategy is curative.

NCERT Solutions Class 12 Biology Chapter 12 has explained the applications of biotechnology in medicine in the above section. Refer to Extramarks to obtain more information on the chapter.

Transgenic Animals

NCERT Solutions Class 12 Biology Chapter 12, in detail, explains the concept of Transgenic animals in the following section.

Transgenic animals are when a new or changed gene has been put into the genome experimentally using genetic engineering techniques.

Rats, rabbits, pigs, sheep, cows, fish, and other transgenic animals are only a few examples. The mouse is the only extant transgenic mammal among all other transgenic animals.

The primary goal of creating transgenic animals is:

  • To make biological products.
  • To investigate the many sorts of illnesses.
  • Third, to examine the role of genes in the progression of the disease.

For example, before vaccinations and medications are used on humans, they must be tested for safety and toxicity.

  • Finally, investigate how genes are controlled and how they impact the body’s regular functioning and development.

Applications in Aquaculture

NCERT Solutions Class 12 Biology Chapter 12 helps understand how to improve fish quality and quantity using biotechnology. To enhance the process of breeding, the gonadotropin-releasing hormone is given to the fish. This aids in their growth and genetic trait improvement. It also helps to avoid a variety of disorders.

Production of Antibiotics

Plants are employed in producing antibiotics that both humans and animals can use.

It helps manufacture medicines, vaccines, and hormone therapy artificial hormones.

Ethical issues:

  • Man’s manipulation of biological beings is akin to his “playing God.” It is a powerful instrument that carries a tremendous deal of responsibility.
  • Any organism’s genetic alteration cannot always be foreseeable. However, it has the potential to trigger a slew of issues in the body.
  • The long-term effects of introducing a GMO into an environment are unknown. It might have unpredictably negative consequences.


NCERT Solutions Class 12 Biology Chapter 12 informs that the Indian Government established the Genetic Engineering Approval Committee to monitor all decisions involving GM research and the safety of GMOs for public use.


Biopiracy is defined as the utilisation of bio-resources discovered in any country by commercial and international corporations and other organisations without obtaining sufficient authority and approval from the governments and people involved and making remuneration.

NCERT Solutions Class 12 Biology Chapter 12 Exercise and Solutions

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Students can access NCERT Solutions Class 12 Biology Chapter 12 and other chapters by clicking here. In addition, students can also explore NCERT Solutions for other classes below.

By getting access to NCERT Solutions Class 12 Biology Chapter 12, students can easily understand all the concepts relating to Biotechnology and its Applications.

Key Features of NCERT Solutions Class 12 Biology Chapter 12

The recently developed concept of NCERT Solutions by Extramarks has gained popularity among students and teachers. These Solutions satisfy all the needs of the students in the easiest way possible. Once a student starts referring to these, there is no going back. Let us see why Extramarks NCERT Solutions have become the comfort zone for students:

  • These solutions help students grasp the basics and answer writing patterns for forthcoming board exams.
  • These solutions have been developed most easily and conveniently possible for the students to catch up.
  • Going through these solutions creates a sense of confidence in students, confident that they have grasped the central concepts of the chapter in one go.

Q.1 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


(c) Toxin is inactive.

[Note: Some strains of Bacillus thuringiensis produce proteins that kill certain insects. The protein crystals are formed during a particular phase of their growth. These crystals contain a toxic insecticidal protein, however, it doesn’t kill the Bacillus because Bt toxin exists as inactive protoxins but once an insect ingests the inactive toxin, it is converted into an active form of toxin. The activated toxin creates pores in the midgut after binding, causes cell swelling and lysis eventually leading to the death of the insect.]

Q.2 What are transgenic bacteria? Illustrate using any one example.


Transgenic bacteria are genetically modified bacteria which have a foreign gene (transgene) inserted in them. These microbes are useful in the production of antibiotics, alcohol, steroids and enzymes which are commercially important biochemicals.

Example of transgenic bacteria:

Diabetes is a very common disease which requires administration of insulin at regular time intervals. Taking insulin produced from other sources like pancreas of cows and pigs slaughtered for food poses severe risks in terms of allergies, etc. This necessitated the need for a recombinant insulin molecule of human origin. Mature human insulin molecule is produced from a pro-hormone and consists of two short polypeptide chains called chain A and chain B, that are linked by disulphide bridges with a challenge to assemble them into a mature form. Now, this can be done by preparing two DNA sequences corresponding to A and B chains of human insulin and introduced them in plasmids of E.coli to produce insulin chains separately. These chains were extracted separately and combined by creating disulphide bonds to make active human insulin, ready for use by humans.

Q.3 Compare and contrast the advantages and disadvantages of production of genetically modified crops.


The plants used in agriculture whose genes have been altered by genetic manipulation are called genetically modified crops (GM crops). The main aim of creating GM crops is introducing new traits which are not present naturally in the parental crop. The advantages of the production of genetically modified crops are as follows:

  1. GM crops are more tolerant to abiotic stresses like cold, drought, salinity and heat.
  2. GM crops have reduced dependence on chemical pesticides (pest-resistant crops), thereby increasing productivity.
  3. GM crops have increased the efficiency of mineral usage by plants, thereby, preventing early depletion of soil minerals.
  4. GM crops have enhanced nutritional food value e.g. golden rice which is enriched with vitamin A.
  5. The post-harvest loss is less in GM crops.

The disadvantages of GM crops are below:

  • There have been many controversies associated with GM crops. No one has actually tested the effect of GM crops on the humankind.
  • Genetically modified ingredients can cause cancer or new allergy outbreaks in humans e.g. genetically modified soya bean containing Brazilian nut protein caused allergies in humans and had to be withdrawn from production.
  • The newer varieties are marketed in less developed countries mostly by developed countries, thus resulting in increased dependence of poor countries on the west.
  • The insect-resistant crops affect the natural biodiversity of the area e.g. Bt-toxin produced in the modified crops affect the natural pollinators like bees.

Q.4 What are Cry proteins? Name an organism that produces it. How has man exploited this protein to his benefit?


Some strains of Bacillus thuringiensis produce proteins that kill certain insects such as lepidopterans, coleopterans and dipterans. These strains produce crystals containing a toxic insecticidal protein called Bt toxin. This protein is called Cry protein and is expressed by a gene named cry gene. During sporulation, many Bt strains produce this crystal protein with insecticidal properties. Scientists exploited this property of crystal proteins for creating genetically modified crops such as Bt cotton, Bt potato, Bt brinjal, Bt tobacco. The cry gene expressing the insecticidal protein was genetically introduced in the parent crop, thus creating a genetically modified Bt crop where the toxin protein expressed by the cry gene acted as an insecticide.

Q.5 What is gene therapy? Illustrate using the example of adenosine deaminase (ADA) deficiency?


Gene therapy is an experimental technique that uses genes to treat or prevent genetic diseases. It either involves replacing a mutated gene that causes disease with a healthy copy of the gene or inactivating, or ’knocking out’, a mutated gene that is functioning improperly in an individual or in an embryo. The expression of the new gene or genes can alter the DNA or RNA transcript used to synthesize proteins and therefore, cure the disease. Gene therapy is still in the experimental stages and is not very widely used.

The first clinical gene therapy was given in 1990 to a 4-year old girl with adenosine deaminase (ADA) deficiency. Adenosine deaminase is important for the normal functioning of the immune system but the disorder is caused in the event of ADA gene deletion. This is cured in some children by bone marrow transplantation or by enzyme replacement therapy however both the methods are not foolproof. This was then tackled by the technique of gene therapy. The lymphocytes from the blood of the patient were grown in a culture outside the body. A functional ADA cDNA was then introduced into these cultured lymphocytes by using a retroviral vector and reintroduced into the patient. Since these now carried a functional ADA gene, active adenosine deaminase enzyme was expressed thereby, giving temporary relief to the patient. Since these cells are not immortal, patients require the regular infusion of such genetically engineered lymphocytes.

Q.6 Diagrammatically represent the experimental steps in cloning and expressing a human gene (say the gene for growth hormone) into a bacterium like E.coli.


Q.7 Can you suggest a method to remove oil (hydrocarbon) from seeds based on your understanding of rDNA technology and chemistry of oil?


Oil consists of glycerols and fatty acids. In order to develop oil-free seeds, one needs to derive a mechanism to silence or inactivate the gene responsible for the production of glycerol and fatty acids. Using rDNA technology the genetic material of an organism can be manipulated to obtain the desired results. Thus, if one wants to get oil-free seeds, genes responsible for the expression of glycerol and fatty acids need to be silenced or inactivated by performing various methods.

Q.8 Find out from internet about golden rice.


  • The aim of producing golden rice was to produce a fortified food to be grown and consumed in areas with a shortage of dietary vitamin A. Vitamin A deficiency kills about hundreds and thousands of children under the age of 5 each year.
  • Golden rice is a genetically modified variety of Oryza sativa rice. It has been produced by genetic engineering in such a way that it biosynthesizes beta-carotene, a precursor of vitamin A, in the edible parts of rice. Golden rice differs from its parental strain by the addition of three beta-carotene biosynthesis genes.
  • The scientific details of the rice were first published in journal Science in 2000. It was the product of an eight-year-long project by Dr. Ingo Potrykus of the Swiss Federal Institute of Technology and Dr. Peter Beyer of the University of Freiburg. This was considered a major breakthrough in biotechnology as an entire biosynthetic pathway was altered by scientists.
  • In 2005, a new variety called Golden Rice 2 was announced which produces up to 23 times more beta-carotene than the original golden rice. Although golden rice was developed as a tool to replace dietary supplement of vitamin A, it has met with significant opposition from environmental and anti-globalization activists.

Q.9 Does our blood have proteases and nucleases?


No, our blood does not contain proteases and nucleases. In human beings, blood serum contains different types of protease inhibitors, which protect the blood proteins from being broken down by the action of proteases. The enzyme, nucleases, catalyzes the hydrolysis of nucleic acids therefore it is absent in the blood.

Q.10 Consult internet and find out how to make orally active protein pharmaceutical. What is the major problem to be encountered?


The orally active protein pharmaceutical are those that can be taken through the oral route. To successfully administer orally active protein pharmaceutical, one needs to put the protein in the form of a tablet whose coating is not affected by the acidic gastric juices. This coating should dissolve only in the intestine, thus releasing the proteins in the intestine from where they can be absorbed by the villi. However, the proteases present in the stomach like pepsin, trypsin and chymotrypsin will act on the orally active protein pharmaceutical and degrade it. The acid of the stomach will denature whatever is remaining after degradation.

The major problem that lies with the development of protein-based pharmaceutical is the fragile nature of the protein and requirement of precise conditions, both in terms of structure as well as surrounding environment, to ensure its activity.

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FAQs (Frequently Asked Questions)

1. What role does NCERT Solutions Class 12 Biology Chapter 12 play in revising the chapter?

NCERT Solutions have been developed by a team of experts that have vast experience of having worked with the educational system and huge familiarity with new exam patterns and syllabus.You will better understand the chapter’s main principles if you practise thoroughly. This will benefit your knowledge of the chapter and your ability to achieve excellent grades in your board exams.

2. What are some of the applications of modern biotechnology??

The technique of generating usable goods from complete organisms or parts of creatures such as tissues, cells, and so on is known as modern biotechnology. DNA profiling, DNA cloning, transgenesis, stem cells, and tissue engineering, genome analysis, and xenotransplantation are some of the most prominent uses of modern biotechnology.