NCERT Solutions for Class 12 Biology Chapter 9 Biotechnology Principles and Processes

Biotechnology principles and processes ncert solutions explain the laboratory techniques used to alter the genetic material of organisms to produce valuable products. This chapter covers essential concepts like recombinant DNA technology, the use of restriction enzymes as molecular scissors, and the various steps involved in scaling up biological production for human welfare and industrial use.

The class 12 biology biotechnology principles and processes NCERT solutions are written as per the latest CBSE syllabus and follow NCERT guidelines closely. These solutions provide clear explanations for all textbook questions, making learning easier for students. Biotechnology principles and processes class 12 NCERT solutions also help students understand diagrams, terminology, and step-by-step processes involved in biotechnology.

For exam preparation, biotechnology principles and processes questions and answers are very useful as they improve concept clarity and answer-writing skills. The chapter 9 biology class 12th solutions include important long, short, and very short questions commonly asked in exams. Overall, these NCERT solutions help students revise efficiently, strengthen fundamentals, and score better marks in Class 12 Biology examinations.

Check Out: CBSE Class 12th Books

Biotechnology Principles and Processes Questions and Answers

Here is the NCERT Solution for Class 12 Biology Chapter 9 Biotechnology Principles and Processes:

1. Can you list 10 recombinant proteins which are used in medical practice? Find out where they are used as therapeutics (use the internet).

Solution : Recombinant proteins are created using recombinant DNA technology and are essential in medical treatments. Here are 10 examples and their uses:

• Interferon-α : Treats chronic hepatitis C.
• Insulin : Used for treating type 1 diabetes.
• Interferon-β : Treats herpes and viral enteritis.
• Interferon B : Used in multiple sclerosis treatment.
• Anti-thrombin III : Helps prevent blood clotting.
• Human recombinant growth hormone : Stimulates growth in children with growth deficiencies.
• Coagulation factor VIII : Used for hemophilia A.
• Coagulation factor IX : Used for hemophilia B.
• DNAase I : Treats cystic fibrosis.
• Tissue plasminogen activator : Used in treating acute myocardial infarction.

2. Make a chart (with diagrammatic representation) showing a restriction enzyme, the substrate DNA on which it acts, the site at which it cuts DNA and the product it produces.

Solution : The restriction enzyme EcoRI cuts DNA at a specific site:

• Enzyme : EcoRI
• Substrate : DNA sequence
• Site : Cuts between GAATTC
• Product : Two fragments with sticky ends: one with an overhanging AATTC sequence.

Read More: NCERT Solutions for Class 12 Biology Chapter 1 Reproduction In Organisms

3. From what you have learnt, can you tell whether enzymes are bigger or DNA is bigger in molecular size? How did you know?

Solution : Enzymes are generally smaller than DNA in terms of molecular size. This is because enzymes are proteins, which are made up of long chains of amino acids, while DNA is a much larger molecule consisting of long sequences of nucleotides.

How we know :

• DNA molecules are large and have a higher molecular weight compared to individual enzymes. For example, the human genome contains approximately 3 billion base pairs of DNA, making it significantly larger than most enzymes, which are proteins typically consisting of hundreds to thousands of amino acids.
• The molecular weight of a typical enzyme (around 20,000–300,000 Da) is much smaller than that of a DNA molecule (which can be millions of Da, especially in organisms with large genomes).

4. What would be the molar concentration of human DNA in a human cell? Consult your teacher.

Solution : The molar concentration of DNA in a human cell can be calculated as:

6.023 × 10²³ × 46 chromosomes = 2.77 × 10²³ moles of DNA in a human diploid cell.

5. Do eukaryotic cells have restriction endonucleases? Justify your answer.

Solution : No, eukaryotic cells do not have restriction endonucleases. Their DNA is protected by methylation, which prevents these enzymes from acting on it. Prokaryotes, however, use these enzymes to protect against viruses.

Read More: NCERT Solutions for Class 12 Biology Chapter 2 Sexual Reproduction In Flowering Plants

6. Besides better aeration and mixing properties, what other advantages do stirred tank bioreactors have over shake flasks?

Solution : Stirred tank bioreactors are used for large-scale biotechnology production and offer several advantages:

• They allow sampling and testing without contamination.
• They have control systems for pH and temperature.
• Foam breakers manage foam formation.

7. Collect 5 examples of palindromic DNA sequences by consulting your teacher. Better try to create a palindromic sequence by following base-pair rules.

Solution : Palindromic sequences read the same backward and forward and are often recognized by restriction enzymes. Examples include:

• GAATTC
• AGCTT
• AAGCTT
• GGATCC
• CCGG

8. Can you recall meiosis and indicate at what stage a recombinant DNA is made?

Solution : In meiosis , recombinant DNA is formed during Prophase I of meiosis, specifically in the pachytene stage .

9. Can you think and answer how a reporter enzyme can be used to monitor the transformation of host cells by foreign DNA in addition to a selectable marker?

Solution : A reporter gene, like the lacZ gene, can be used to track whether the foreign DNA has been successfully incorporated into the host cell. The reporter gene produces a visible marker, such as fluorescence, indicating successful transformation.

Read More: NCERT Solutions for Class 12 Biology Chapter 3 Human Reproduction

10. Describe briefly the following:

• (a) Origin of replication : A DNA sequence where replication begins. It allows DNA to replicate within a host cell and can be linked to vectors to amplify specific DNA sequences.
• (b) Bioreactors : Large vessels used for growing organisms in controlled environments to produce biotechnological products.
• (c) Downstream processing : The process of isolating and purifying products after biosynthesis, followed by formulation and clinical trials.

11. Explain briefly.

(a) PCR

(b) Restriction enzymes and DNA

(c) Chitinase

Solution:

(a) PCR (Polymerase Chain Reaction) PCR is a technique used to amplify or make multiple copies of a specific DNA fragment. It allows researchers to obtain a large quantity of DNA from a small sample. PCR involves three main steps:

1. Denaturation: The DNA sample is heated to high temperatures (usually around 94-98°C) to separate the two strands of DNA.
2. Annealing: The temperature is lowered (usually around 50-65°C) to allow primers (short sequences of nucleotides) to bind to the target DNA sequence.
3. Extension: The temperature is raised to around 75-80°C, allowing the Taq DNA polymerase (a heat-resistant enzyme from Thermus aquaticus ) to synthesize the complementary DNA strand, extending the primers.

These steps are repeated for several cycles, leading to the amplification of the target DNA region. (b) Restriction Enzymes and DNA Restriction enzymes, also known as molecular scissors, are proteins that cut DNA at specific sequences. These enzymes are crucial in genetic engineering and molecular biology. They recognize a specific sequence of nucleotides in DNA (the recognition site) and cut the DNA at or near this sequence. For example, the restriction enzyme EcoRI cuts DNA at a specific 6-base pair sequence. There are two main types of restriction enzymes:

1. Endonucleases: These enzymes cut within the DNA molecule, typically creating sticky ends, which can be used to join the DNA fragments with other sequences using DNA ligase.
2. Exonucleases: These enzymes remove nucleotides from the ends of the DNA molecule, either from the 3' or 5' end.

(c) Chitinase Chitinase is an enzyme that breaks down chitin, a polysaccharide found in the cell walls of fungi and the exoskeletons of arthropods. In molecular biology, chitinase is often used to degrade the cell walls of fungi to release their genetic material. This is particularly useful in DNA extraction from fungal cells, as it helps to break down the fungal cell walls, allowing the release of the DNA enclosed within the cell membrane.

12. Discuss with your teacher and find out how to distinguish between

(a) Plasmid DNA and Chromosomal DNA

(b) RNA and DNA

(c) Exonuclease and Endonuclease

(a) Plasmid DNA vs. Chromosomal DNA

(b) RNA vs. DNA

(c) Exonuclease vs. Endonuclease

Why Study Biotechnology Principles and Processes?

Biotechnology is a field that acts as a bridge between biology and technology, utilizing living organisms to make products useful to humans. When you look at class 12 biotechnology principles and processes ncert solutions, you will find that the subject is built on two core pillars: Genetic Engineering and Bioprocess Engineering. Genetic engineering allows us to change the chemistry of genetic material (DNA and RNA) to alter the host organism's traits.

Whether you are looking for a biotechnology principles and processes question answer or trying to understand how a bioreactor works, this chapter is high-yield for your exams. It focuses on the creation of recombinant DNA, the use of gene cloning, and gene transfer. These techniques allow us to isolate and introduce only desirable genes without bringing along unwanted ones, which is a major advantage over traditional hybridization.

Biotechnology Principles and Processes NCERT Solutions: Key Tools

The class 12 biology biotechnology principles and processes ncert solutions highlight that specific biological "tools" are needed to manipulate DNA. Let’s break down the most important ones mentioned in the source materials.

The Role of Restriction Enzymes

These are often called "molecular scissors." They belong to a larger class of enzymes called nucleases. Exonucleases remove nucleotides from the ends of DNA, while endonucleases make cuts at specific positions within the DNA. Each restriction endonuclease functions by inspecting the length of a DNA sequence and binding to a specific recognition sequence, often a palindromic nucleotide sequence.

Cloning Vectors and Competent Hosts

A vector, such as a plasmid or a bacteriophage, acts as a vehicle to deliver a foreign DNA segment into a host cell. To be a good vector, it needs an origin of replication (ori), selectable markers to identify transformants, and cloning sites. For the host to take up the DNA, it must be made "competent." This is often done by treating the cells with a specific concentration of a divalent cation, such as calcium, followed by a heat shock.

Check Out: NCERT Solutions for Class 12 Biology Chapter 4

The Process of Recombinant DNA Technology

The chapter biotechnology principles and processes ncert solutions outline a very specific sequence of events required to successfully clone a gene.

1. Isolation of Genetic Material: Since DNA is enclosed within membranes, we use enzymes like lysozyme (bacteria), cellulase (plants), or chitinase (fungi) to break the cells open. Chilled ethanol is then used to precipitate the purified DNA.

2. Cutting DNA and Amplification: DNA is cut at specific sites using restriction enzymes. If we need many copies of a specific gene, we use the Polymerase Chain Reaction (PCR). This involves three steps: Denaturation, Annealing, and Extension.

3. Insertion and Extraction: The ligated DNA is introduced into the host. Once the host starts multiplying, it expresses the foreign gene to produce a desirable protein.

Scaling Up and Downstream Processing

To make biotechnology useful for the world, we need to produce these proteins in massive quantities. This is where class 12 biology chapter 9 biotechnology principles and processes question answer sections focus on industrial-scale production.

Using Bioreactors

A bioreactor is a large vessel (100–1000 liters) where raw materials are biologically converted into specific products. The most common type is the stirred-tank bioreactor. It is designed to provide optimal growth conditions, including the right temperature, pH, vitamins, and oxygen levels.

Downstream Processing

After the biosynthesis stage is complete, the product must go through a series of processes before it is ready for marketing. This includes separation and purification, collectively known as downstream processing. The product is then formulated with suitable preservatives and undergoes clinical trials and quality control testing to ensure safety and efficacy.

Check Out: Class 12th Sample Papers

How PW Class 12 Study Material Help in Board Exams?

If terms like "palindromic sequences" or "bioreactors" feel a bit difficult, you're not alone. To truly master biotechnology principles and processes, you need resources that make these invisible processes clear. The PW Store offers specialized Biology books that act as a complete success guide for your board exams.

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Also Check: Class 12th Question Banks

NCERT Solutions for Class 12 Biology Chapter 9 FAQs

Q1: What is a palindromic sequence in DNA?

In biotechnology, a palindrome is a sequence of base pairs that reads the same on the two strands when the orientation of reading is kept the same (e.g., 5' to 3'). Restriction enzymes usually cut at these specific sites. 

Q2: What is the purpose of chilled ethanol in DNA isolation?

Chilled ethanol is added to the solution to precipitate the purified DNA. The DNA can then be seen as a collection of fine threads in the suspension. This is a common biotechnology principles and processes question answer in practical exams.

Q3: How does the Polymerase Chain Reaction (PCR) help in biotechnology?

PCR allows for the amplification of a specific gene of interest. With two sets of primers and the enzyme DNA polymerase, billion-fold copies of a DNA segment can be made in a short time. This is a high-yield topic in class 12 biology biotechnology principles and processes.

Q4: What is the difference between an exonuclease and an endonuclease?

Exonucleases remove nucleotides from the ends of the DNA, while endonucleases make cuts at specific points inside the DNA molecule. This distinction is vital for understanding how "molecular scissors" work.

Q5: What are the main components of a stirred-tank bioreactor?

A stirred-tank bioreactor usually has an agitator system, an oxygen delivery system, a foam control system, a temperature control system, and a pH control system. These ensure the best environment for cell growth.