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

Biotechnology: Principles and Processes Class 12 Biology is a chapter where students learn about the use of biological systems and organisms to develop useful products through scientific techniques. The chapter also includes various concepts such as the basic principles of genetic engineering, tools used in biotechnology and steps involved in creating recombinant DNA.

ALLEN provides quality NCERT Solutions with logical, step-by-step guides to assist learners in comprehending these topics. Our expert faculty has designed these materials to emphasise clarity, so that complicated ideas such as electrophoresis of gels and bioprocess engineering are easy to understand and memorise. With the structured explanations given by ALLEN, students can compare their answers with the specific requirements of the CBSE marking scheme, thereby developing confidence and accuracy to excel in their school finals and competitive medical entrance tests.

1.0Key Concepts of Class 12 Biology Chapter 9 Biotechnology: Principles and Processes

The chapter focuses on understanding the methods and tools used in genetic engineering. Some of the key lessons covered in this chapter are given below:

Principles of Biotechnology: Understand the two main foundations of biotechnology: genetic engineering and bioprocess engineering.
Tools of Recombinant DNA Technology: Learn about restriction enzymes, DNA ligase, cloning vectors, and suitable host organisms used to create recombinant DNA.
Isolation of Genetic Material: Study how DNA is extracted from cells and purified for use in genetic engineering experiments.
Polymerase Chain Reaction: Understand how PCR is used to produce multiple copies of a specific DNA segment through repeated cycles.
Cloning Vectors: Learn how plasmids and bacteriophages can act as carriers for introducing foreign DNA into host cells.
Introduction of Recombinant DNA into Host Cells: Understand methods used to transfer recombinant DNA into suitable host organisms and select the desired transformed cells.
Bioreactors: Learn how genetically modified organisms are grown under controlled conditions for the large-scale production of biological products.
Downstream Processing: Understand the steps involved in separating, purifying, and preparing the final biological product after production.

2.0NCERT Class 12 Biology Chapter 9 Biotechnology: Principles and Processes : Detailed Solutions

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

Ans.

Recombinant Proteins	Therapeutic Uses
Human Insulin (Humulin)	Treatment of diabetes type-1
Human growth hormone	Replacement of missing hormone in short stature people
Platelet Growth factor	Stimulation of wound healing
Calcitonin	Treatment of rickets
Blood clotting factor VIII/IX	Replacement of clotting factor missing in patients with Haemophilia A/B
Hirudin	Used as an anticoagulant
Interferon	Treatment of viral infection and cancer
Chorionic Gonadotropin	Treatment of infertility
Interleukins	Enhancing activity of immune system
Tissue Plasminogen Activator	Treatment for acute myocardial infarction; dissolves blood clot after heart attack and stroke

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. [IMP.]

Ans.

ques-2-sol-chap-9-class-12-biology

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

Ans. DNA is bigger in molecular size. DNA is made up of sugar, phosphate and nitrogenous bases. An enzyme is made up of only one or few polypeptides.

Enzyme is synthesized from a portion of DNA.

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

Ans. The molar concentration of human DNA in a human diploid cell as follow:

• Total number of chromosomes × 6.023 × 1023

• 46 × 6.023 × 1023

• 277.06 × 1023 Moles.

Hence, the molar concentration of DNA in each diploid cell in human is 277.06 × 1023 moles.

Do eukaryotic cells have restriction endonucleases? Justify your answer. [IMP.]

Ans. Eukaryotic cells have no restriction enzymes as the DNA molecules of eukaryotes are heavily methylated.

It is present in prokaryotic cell (like bacteria) where these act as defense mechanism to restrict the growth of bacteriophages.

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

Ans. Shake flask is used for a small–scale production but the stirred-tank bioreactors are used for large scale production of biotechnological products.

Advantages of stirred - tank bioreactors over shake flasks are that these facilitate –

• Temperature control system,

• pH control system,

• Foam control system and

• Sampling ports from where small, volume of the cultures can be obtained and tested time to time.

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

Ans. (i) 5' GAATTC 3'

3' CTTAAG 5'

(ii) 5' GGATCC 3'

3' CCTAGG 5‘

(iii) 5' ACTAGT 3'

3' TGATCA 5'

(iv) 5' AAGCTT 3'

3' TTCGAA 5'

(v) 5' AGGCCT 3'

3' TCCGGA 5'

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

Ans. Meiosis is the cell division process of gamete formation. It occurs in two steps –

Meiosis-I and Meiosis-II

During pachytene stage of prophase–I of meiosis-I, crossing over takes place between non-sister chromatids of homologous chromosomes and a recombinant DNA is made.

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? [IMP.]

Ans. A reporter gene is used to monitor the transformation of host cells by foreign DNA. They act as a selectable marker to determine whether the host cell has taken up the foreign DNA or the foreign gene gets expressed in the cell.

Here, the reporter gene is used as a selectable marker to find out the successful uptake of gene of interest.

An example of reporter gene includes lac Z gene which encodes β-galactosidase enzyme.

Describe briefly the following:

(a) Origin of replication

(b) Bioreactors

(c) Downstream processing

Ans.

(a) Origin of replication:- It is a DNA sequence that initiates any piece of linked DNA to replicate and is also called ori site. It controls the copy numbers of the linked DNA.

(b) Bioreactors:-Bioreactors are vessels of large volumes (100-1000 liters) in which raw materials are biologically converted into specific products.

• It provides the optimal conditions for achieving the desired product by providing optimal growth conditions like temperature, pH, substrates, salts vitamins and oxygen. Stirred tank bioreactors are commonly used bioreactors.

A bioreactor has the following components.

(i) An agitator system

(ii) An oxygen delivery system

(iii) Foam control system

(iv) Temperature control system

(v) pH control system

(vi) Sampling ports to withdraw cultures periodically

(c) Downstream processing - All the process to which a product has to be subjected through a series of processes before it is ready for marketing as a finished product called downstream processing.

• It includes separation of the product from the reactor.

• Purification of the product.

• Formulation of the product with suitable preservatives.

• Quality control testing and trials in case of drugs.

Explain briefly.

(a) PCR

(b) Restriction enzymes and DNA

(c) Chitinase

Ans.

(a) PCR - PCR stands for polymerase chain reaction, which is a method for amplification of small segments of DNA.

(b) Restriction enzymes and DNA - Restriction enzymes are called ‘molecular scissors’ because they cut the helix of DNA at a specific site. DNA is the genetics material, which carries and pass the genetic characters or information from one generation to other.

(c) Chitinase - Chitinase is an enzyme which is used to degrade the cell wall of fungi to release its cellular components.

Discuss with your teacher and find out how to distinguish between. [IMP.]

(A) Plasmid DNA and chromosomal DNA

(B) DNA and RNA

(C) Exonuclease and endonuclease

Ans.

(A) Plasmid DNA and chromosomal DNA

Plasmid DNA	Chromosomal DNA
This is present in prokaryotic cells, e.g., bacteria.	This is present in both prokaryotic and eukaryotic cells.
This is circular extra-chromosomal DNA, not associated with histone proteins.	It is linear and associated with histone proteins in eukaryotes, but it is double-stranded and circular in prokaryotes.
It gives extra characters to prokaryotes, like antibiotic resistance.	It contains genes for characters essential for the life of the organism.

(B) DNA and RNA

DNA	RNA
It has deoxyribose sugar.	It has ribose sugar.
It has A, G, C, T nitrogen bases in its nucleotide.	It has A, G, C, U nitrogen bases in its nucleotide.
It is double stranded.	It is mostly single stranded.
It acts as genetic material in almost all organisms.	It acts as genetic material in only some viruses.
DNA can't be catalytic.	It can be catalytic (Ribozyme).

(C) Exonuclease and Endonuclease

Exonuclease

Endonuclease

Remove nucleotides from ends of the DNA.

Cut at specific positions within the DNA.

They are end specific.

They are site specific.

e.g. Exonuclease-I

e.g.

EcoRI

3.0NCERT Solutions for Class 12 Biology | Other Chapter-wise Links

Get chapter-wise NCERT Solutions for Class 12 Biology with detailed solutions, easy explanations, and answers to textbook questions from the links provided below.

Chapter Number	Chapterwise NCERT Solutions
Chapter 1	Sexual Reproduction in Flowering Plants
Chapter 2	Human Reproduction
Chapter 3	Reproductive Health
Chapter 4	Principles of Inheritance and Variation
Chapter 5	Molecular Basis of Inheritance
Chapter 6	Evolution
Chapter 7	Human Health and Disease
Chapter 8	Microbes in Human Welfare
Chapter 10	Biotechnology and Its Applications
Chapter 11	Organisms and Populations
Chapter 12	Ecosystem
Chapter 13	Biodiversity and Conservation

4.0Key Features and Benefits of Class 12 Biology Chapter 9 Biotechnology: Principles and Processes

Clear Understanding of Biotechnology: Learn how genetic material is isolated, modified, and introduced into suitable host organisms through recombinant DNA technology.
Step-by-Step Processes: Understand important procedures such as DNA isolation, cutting and joining of DNA, gene transfer, and selection of transformed cells through clear explanations.
Important Diagrams and Flowcharts: Use well-structured explanations to understand and revise complex biotechnology processes, tools, and techniques more easily.
Application-Based Learning: Connect biotechnology concepts with practical applications in medicine, agriculture, industry, and the production of useful biological products.
NCERT-Based Practice: Strengthen your understanding by practising questions based on the concepts, processes, tools, and techniques covered in the NCERT textbook.
Strong Foundation for NEET: Build a solid understanding of genetic engineering and recombinant DNA technology for NEET and further studies in biotechnology and related fields.