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

NCERT Solutions for Class 12 Biotechnology Principles and Processes: Chapter-wise NCERT solutions for Class 12 Biology, Chapter 9, Biotechnology Principles and Processes are available here. There are a total of 12 questions in the exercises given at the end of this chapter. Here, you will find detailed Class 12 Biology NCERT Solutions for all the questions. These solutions are also helpful for students preparing for medical entrance examinations like NEET (National Eligibility cum Entrance Test). 

Key Features of NCERT Solutions for Class 12 Biology Chapter 9 – Biotechnology Principles and Processes

• Comprehensive Coverage
• Step-by-Step Approach
• Diagrams and Illustrations
• Clear and Concise Language
• Relevance to Examinations
• Extra Insights
• Practice Exercises
• Applications in Real Life
• Interdisciplinary Connection
• Self-Assessment
• Useful for Exams
• Alignment with NCERT Textbook

Biotechnology Principles and Processes NCERT Solutions

Find below NCERT Solutions for Class 12 Biology, Chapter 9; Biotechnology: Principle and Processes. You can also download these solutions in PDF format. NCERT textbook and NCERT Solutions are important for CBSE Class 12 board exams as well as medical entrance exams.

Question1. Can you list 10 recombinant proteins which are used in medical practice? Find out where they are used as therapeutics (use the internet).

Solution1.

This list might differ based on the knowledge you have. You can any different example as well.

Question2. 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.

Solution2.

Restriction- Eco R1

Enzyme source- E.coli

Recognition- 5’—GAATTC

3’—CTTAAG

Sequence- 5’—G

3’—CTTAA

Products- AATTC-3’

G-5’

Question3. From what you have learnt, can you tell whether enzymes are bigger or DNA is bigger in molecular size? How did you know?

Solution3.

Proteins are made from amino acids which is joined through peptide bonds.

In nature 20 different kinds of amino acids are found. Avg. Protein length is around 300 residues of amino acids. Some of like actin are made up of thousand actin molecules. DNA is made up of polymers of nucleotides.

DNA polymers can be enormous molecules containing million of nucleotides. Like human chromosome is made up of 220 millions base pairs. So, DNA is bigger in molecular size.

Question4. What would be the molar concentration of human DNA in a human cell? Consult your teacher.

Solution4.

The molar concentration of human DNA in a human diploid cell will be approximately:

No: of human chromosome in human cell = 46

So,

= Chromosome no. X Avogadro No.

=46 x 6.023 x10²³

=2.77x10²⁵ moles.

Hence, the molar conc. will be approximately 2.77 x 10²⁵.

Question5. Do eukaryotic cells have restriction endonucleases? Justify your answer.

Solution5.

Eukaryotic cells do not naturally possess restriction endonucleases. These enzymes, commonly found in prokaryotic cells like bacteria and archaea, play a pivotal role in prokaryotic immune systems, allowing them to cut and inactivate foreign DNA. Eukaryotic cells, which constitute the complex organisms of the plant, animal, fungi, and protist kingdoms, rely on a different set of defense mechanisms against invading genetic material.

Question6. Besides better aeration and mixing properties, what other advantages do stirred tank bioreactors have over shake flasks?

Solution6.

Stirred tank bioreactors provide a better agitation system, oxygen delivery system, foam system, pH control system, temperature control system and provide a better provision for cleaning and sterilization.

Question7. Collect 5 examples of palindromic DNA sequences by consulting your teacher. Better try to create a palindromic sequence by following basepair rules.

Solution7.

Palindromic DNA sequences are a group of letters that form the same sequence when read from both forward and backward.

Like,

Example 1

5’ – GAATTC – 3’

3’ – CTTAAG – 5’

Example 2

5'-TTAGGG-3'

3'-AATCCC-5'

Example 3

5'-GAGCTC-3'

3'-CTCGAG-5'

Example 4

5'-GCTAGC-3'

3'-CGATCG-5'

Example 5

5'-AGCT-3'

3'-TCGA-5'

Question8. Can you recall meiosis and indicate at what stage a recombinant DNA is made?

Solution8.

Meiosis is a specialised form of cell division that occurs in sexually reproducing organisms, resulting in the formation of gametes (sperm and egg cells) with half the number of chromosomes compared to the parent cell. Meiosis consists of two successive divisions: meiosis I and meiosis II, each with specific stages.

Recombination of DNA, also known as genetic recombination, occurs during meiosis, specifically in meiosis I, at the Prophase I stage. This is a critical event in meiosis and contributes to genetic diversity among offspring.

Question9. Can you think and answer how a reporter enzyme can be used to monitor transformation of host cells by foreign DNA in addition to a selectable marker?

Solution9.

There are many methods of introducing the ligated DNA into recipient cells, after making them “competent” to receive and take up DNA present in its surrounding. So if a recombinant DNA bearing gene for resistance to an antibiotic is transferred into E.coli cells, the host cells become transformed into ampicillin resistant cells. Since due to ampicillin resistance gene, one is able to select a transformed call in the presence of ampicillin.

When we insert a piece of alien DNA into a cloning vector and transfer it into a bacterial, plant or animal cell, the alien DNA gets multiplied. The whole process involves the use of restriction endonucleases, DNA ligase, appropriate plasmid or viral factors to isolate and ferry the foreign DNA into host organisms.

Question10. Describe briefly the followings:

(a) Origin of replication

(b) Bioreactors

(c) Downstream processing

Solution10.

(a) Origin of replication: It is the site on the DNA molecule at which replication starts. Thus, a DNA to be increase in number should have a origin of replication. Also called Ori site. 

(b) Bioreactors: Bioreactors are vessels in which raw materials are biologically converted into specific products, individual enzyme, etc., using microbial plants, animal or human cells. A bioreactor provides the optimal conditions for achieving the desired product by providing optimum growth conditions (temperature, pH, substrate, salts, vitamins, oxygen).

(c) Downstream processing: After the biosynthetic stage, the products are subjected through a series of processes, such as separation and purification, before it is ready for marketing as a finished product.

These processes are referred to as downstream processing.

Question11. Explain briefly

(a) PCR

(b) Restriction enzymes and DNA

(c) Chitinase

Solution11.

(a) PCR: PCR means polymerase chain reaction. In this reaction multiple copies of gene of interest is synthesised in vitro using two sets of primers and the enzyme DNA polymerase. The enzyme extends the primers using the nucleotides provided in the reaction and the genome DNA as template. The segment of DNA can be amplified to approximately billion ties if the process of replication of DNA is repeated many times.

(b) Restriction enzymes and DNA: Restriction enzymes are also called molecular scissors. By the use of restriction enzymes it is possible to cut DNA sequence. It acts on both the strands and produce a break.

When restriction enzymes make a cut in DNA strand, it will leave a single stranded portion at ends. These are overhanging called sticky ends. Sticky ends can make H-bonds with their complementary cut counterparts by DNA ligase.

(c) Chitinase: It is a type of enzyme which is treated with animal or plant tissue to break the cell open to release DNA along with other macromolecules such as RNA, proteins etc.

Question12. 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

Solution12.

(a) Plasmid DNA and Chromosomal DNA

(b) RNA and DNA

(c) Exonuclease and endonucleases