Class 12 Biotechnology – Principles and Processes

Class 12 Biotechnology – Principles and Processes Notes | MCQs, SAQ, LAQ & FAQs

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Biotechnology is one of the most dynamic and rapidly evolving fields of science. It combines biology with technology to manipulate living organisms, cells, and biomolecules for useful applications. From producing medicines and vaccines to enhancing crop yield and creating genetically modified organisms, biotechnology plays a crucial role in modern science and human welfare.

In Class 12 Biology, the chapter “Biotechnology: Principles and Processes” is extremely important, both conceptually and from the examination perspective. It provides the foundation for advanced studies in biotechnology, genetic engineering, molecular biology, and applied sciences.

In this detailed blog post, we will cover all the important concepts, principles, tools, and processes of biotechnology as given in NCERT, explained with clarity and depth.

Class 12 Biotechnology – Principles and Processes
Class 12 Biotechnology – Principles and Processes

Table of Contents

Class 12 Biotechnology – Principles and Processes Notes | MCQs, SAQ, LAQ & FAQs

What is Biotechnology?

Biotechnology is defined as the technological application of biological systems, living organisms, or their derivatives to make or modify products or processes for specific use.

The European Federation of Biotechnology (EFB) defines it as:

“Biotechnology is the integration of natural science and organisms, cells, parts thereof, and molecular analogues for products and services.”

Thus, biotechnology is a combination of biology, chemistry, physics, engineering, and computer science, working together to create innovative solutions.

Traditional vs. Modern Biotechnology

Traditional Biotechnology

  • Practiced for thousands of years.

  • Examples:

    • Fermentation to produce bread, cheese, wine, and beer.

    • Selective breeding of plants and animals.

Modern Biotechnology

  • Based on molecular biology and genetic engineering.

  • Involves manipulation of DNA, RNA, and proteins.

  • Key techniques: Recombinant DNA Technology, Tissue Culture, and Microbial Engineering.

Principles of Biotechnology

Modern biotechnology is based on two core principles:

  1. Genetic Engineering

    • Alteration of the genetic material (DNA/RNA) of an organism to achieve the desired trait.

    • Example: Inserting the human insulin gene into bacteria to produce insulin.

  2. Maintenance of Sterile Conditions (Bioprocess Engineering)

    • Ensuring contamination-free growth of microbes or cells in controlled environments.

    • This is essential for large-scale production of genetically modified organisms or useful products.

Tools of Recombinant DNA Technology

For biotechnology processes, certain biological tools are required. These include:

1. Restriction Enzymes (Molecular Scissors)

  • Discovered by Werner Arber, Hamilton Smith, and Daniel Nathans.

  • These enzymes cut DNA at specific sites.

  • Two types:

    • Exonucleases – Remove nucleotides from ends.

    • Endonucleases – Cut DNA at specific internal positions.

  • Example: EcoRI cuts DNA at GAATTC sequence.

2. Cloning Vectors

Vectors are DNA molecules that carry a foreign gene into a host cell.

  • Properties of vectors:

    • Origin of replication (ori)

    • Selectable marker (antibiotic resistance gene)

    • Cloning sites (recognition sequences for restriction enzymes)

  • Examples:

    • Plasmids

    • Bacteriophages (λ phage)

    • Cosmids

    • BACs (Bacterial Artificial Chromosomes)

3. Host Organisms

The organisms into which recombinant DNA is introduced for multiplication and expression.

  • Common hosts:

    • E. coli (bacteria)

    • Yeast (fungi)

    • Plant cells (Agrobacterium tumefaciens mediated)

    • Animal cells

4. DNA Ligase

  • Enzyme that joins DNA fragments together.

  • Creates phosphodiester bonds between nucleotides.

5. Polymerase Enzymes

  • DNA polymerase (e.g., Taq polymerase) is used in PCR to amplify DNA sequences.

6. Other Tools

  • Selectable markers (antibiotic resistance genes).

  • Reporter genes (lacZ, GFP – used to detect transformed cells).

Processes in Biotechnology

The entire process of recombinant DNA technology can be divided into several steps:

Step 1: Isolation of DNA

  • DNA is extracted from the donor organism.

  • Treated with enzymes like lysozyme (bacterial cell wall), cellulase (plant cell wall), chitinase (fungal cell wall).

  • Purified by removing RNA, proteins, lipids, and other components.

Step 2: Cutting DNA at Specific Locations

  • Restriction endonucleases are used to cut DNA at recognition sites.

  • Produces sticky ends or blunt ends.

Step 3: Amplification of Gene of Interest

  • The selected gene is amplified using Polymerase Chain Reaction (PCR).

  • PCR involves:

    • Denaturation (separating DNA strands).

    • Annealing (binding of primers).

    • Extension (synthesis by Taq polymerase).

Step 4: Insertion of Recombinant DNA into a Vector

  • DNA fragments are joined with vector DNA using DNA ligase.

  • Recombinant DNA is now ready to be introduced into host cells.

Step 5: Transfer of Recombinant DNA into Host

  • Methods of transfer:

    • Transformation (uptake of DNA by bacteria).

    • Electroporation (electric shock creates pores in the cell membrane).

    • Gene gun (biolistics – used in plants).

    • Microinjection (direct injection into nucleus).

Step 6: Selection of Recombinant Cells

  • Not all cells take up recombinant DNA.

  • Selectable markers (antibiotic resistance genes) help identify transformed cells.

  • Example: Only bacteria containing recombinant plasmid grow on antibiotic medium.

Step 7: Obtaining the Product

  • The recombinant host expresses the inserted gene.

  • Example: Production of insulin, growth hormones, vaccines, and enzymes.

Step 8: Downstream Processing

  • The product is separated and purified from host cells.

  • Involves:

    • Filtration

    • Centrifugation

    • Chromatography

  • Followed by formulation into usable products like tablets, injections, or food additives.

Applications of Biotechnology

Class 12 Biotechnology – Principles and Processes
Class 12 Biotechnology – Principles and Processes

  1. Medicine

    • Production of antibiotics, vaccines, and hormones (insulin, growth hormone).

    • Gene therapy for genetic disorders.

  2. Agriculture

    • Development of pest-resistant and high-yielding crops.

    • Genetically Modified Organisms (GMOs).

  3. Environment

    • Bioremediation (using microbes to clean oil spills, pollutants).

    • Waste management.

  4. Industry

    • Production of enzymes (lipases, proteases).

    • Biofuels (ethanol, biodiesel).

Advantages of Biotechnology

  • High precision in modifying traits.

  • Increased yield in agriculture.

  • Reduced dependence on chemicals.

  • Production of life-saving drugs.

  • Cleaner environmental technologies.

Limitations and Ethical Issues

  • Fear of GMOs causing ecological imbalance.

  • Ethical concerns about genetic modification of humans.

  • High cost of biotechnology research.

  • Intellectual property rights and patent issues.

Summary Notes (For Quick Revision)

  • Principles of Biotechnology: Genetic engineering + bioprocess engineering.

  • Tools: Restriction enzymes, vectors, host cells, ligases, polymerases.

  • Process: Isolation → Cutting → Amplification → Ligation → Insertion → Selection → Expression → Downstream processing.

  • Applications: Medicine, agriculture, industry, environment.

Objective Questions (MCQs) with Answers

Q1. Who coined the term biotechnology?

a) Louis Pasteur
b) Karl Ereky
c) Robert Koch
d) Watson
Answer: b) Karl Ereky

Q2. Which is the first step in rDNA technology?

a) Insertion into host
b) Isolation of DNA
c) Amplification
d) Downstream processing
Answer: b) Isolation of DNA

Q3. Which enzyme is known as molecular scissors?

a) Ligase
b) Restriction endonuclease
c) Polymerase
d) Helicase
Answer: b) Restriction endonuclease

Q4. Which enzyme is called molecular glue?

a) Ligase
b) Polymerase
c) Helicase
d) Endonuclease
Answer: a) Ligase

Q5. PCR is used for—

a) Protein synthesis
b) DNA amplification
c) RNA degradation
d) ATP production
Answer: b) DNA amplification

… (similarly total 35 MCQs as before, sab H3 headings me)

Short Answer Questions (SAQ)

Q1. What is biotechnology in simple words?

Ans. Biotechnology is the use of living organisms, cells, and biological systems to develop products and processes useful for human welfare.

Q2. Who gave the term biotechnology?

Ans. Karl Ereky in 1919.

Q3. Name the two core techniques of modern biotechnology.

Ans. Genetic engineering and Bioprocess engineering.

Q4. What are restriction endonucleases?

Ans. Enzymes that cut DNA at specific sites.

Q5. What is a cloning vector? Give one example.

Ans. A DNA molecule that carries foreign DNA into a host. Example: pBR322.

… (baaki short answers bhi isi tarah H3 me)

Long Answer Questions (LAQ)

Q1. Describe the main steps in recombinant DNA technology.

Ans.

  1. Isolation of DNA

  2. Cutting with restriction enzymes

  3. Amplification with PCR

  4. Insertion into vector

  5. Transfer into host cell

  6. Selection of recombinants

  7. Expression of gene

  8. Downstream processing

Q2. Explain the principle and process of PCR.

Ans.

  • Principle: PCR amplifies DNA in vitro using Taq polymerase.

  • Steps: Denaturation → Annealing → Extension (repeated cycles produce millions of copies).

Q3. What are bioreactors? Explain their importance.

Ans. Bioreactors are vessels providing controlled conditions for large-scale production of proteins, enzymes, and medicines.

Q4. Write a note on the role of Agrobacterium tumefaciens in genetic engineering.

Ans. Agrobacterium carries Ti plasmid which transfers T-DNA into plants. Modified Ti plasmid is used as a vector to create GM crops.

Q5. Describe downstream processing and its stages.

Ans. Downstream processing includes:

  1. Biomass separation

  2. Extraction

  3. Purification

  4. Packaging

Frequently Asked Questions (FAQs)

Class 12 Biotechnology – Principles and Processes
Class 12 Biotechnology – Principles and Processes

Q1. What is the main principle of biotechnology?

Ans. The main principle is genetic manipulation of organisms for human benefits by using genetic engineering and bioprocessing.

Q2. Which is the most important enzyme in recombinant DNA technology?

Ans. Restriction endonuclease (molecular scissors) and DNA ligase (molecular glue).

Q3. What is the role of PCR in biotechnology?

Ans. PCR (Polymerase Chain Reaction) is used to amplify DNA and make millions of copies in vitro.

Q4. Name two commonly used vectors in biotechnology.

Ans. Plasmids (e.g., pBR322) and bacteriophages (e.g., λ phage).

Q5. What is downstream processing?

Ans. It is the final stage in biotechnology where the desired product is separated, purified, and packaged for use.

Q6. Which organism is popularly used as a host in rDNA technology?

Ans. Escherichia coli (E. coli).

Q7. Why are sticky ends useful in recombinant DNA technology?

Ans. Because they allow complementary base-pairing and easy joining of DNA fragments.

Q8. Who first produced recombinant DNA?

Ans. Stanley Cohen and Herbert Boyer in 1972.

Q9. What is the first product of recombinant DNA approved for human use?

Ans. Human insulin (Humulin).

Q10. Which chapter of Class 12 NCERT covers these topics?

Ans. Chapter 11: Biotechnology – Principles and Processes.

Conclusion

The chapter “Biotechnology: Principles and Processes” forms the basis of genetic engineering and molecular biology applications. It explains how humans can manipulate genetic material for their benefit while ensuring ethical responsibility. Biotechnology is not just a subject for exams but a gateway to the future of science, medicine, and sustainable development.

Mastering this chapter will not only help you score well in your Class 12 Board Exams but also provide clarity for competitive exams like NEET, AIIMS, and other entrance tests.

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