NCERT Textbook: Tools and Technologies | Biotechnology for Class 11 - NEET PDF Download

 Page 1


Tools and 
Techniques: 
Basic Concepts
Unit V
Chapter 12 
Tools and Techniques
Considering the fact that biotechnology is 
an experimental science and involves a lot of 
experimentations; therefore, research in this ??eld 
depends highly on sophisticated laboratory methods. 
Advances in biotechnology were closely followed by 
the development of newer tools and techniques in 
biological sciences. These new methods opened new 
avenues for research and investigation in the ??eld 
of biotechnology. It is, thus, important to appreciate 
the experimental tools available to biotechnologists 
in order to understand the progress and future 
directions of this rapidly moving area of science. 
Some of the important experimental methods 
including methods of cell and molecular biology 
will be discussed in this unit. 
Chapter 12.indd   279 09/01/2025   15:17:36
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Page 2


Tools and 
Techniques: 
Basic Concepts
Unit V
Chapter 12 
Tools and Techniques
Considering the fact that biotechnology is 
an experimental science and involves a lot of 
experimentations; therefore, research in this ??eld 
depends highly on sophisticated laboratory methods. 
Advances in biotechnology were closely followed by 
the development of newer tools and techniques in 
biological sciences. These new methods opened new 
avenues for research and investigation in the ??eld 
of biotechnology. It is, thus, important to appreciate 
the experimental tools available to biotechnologists 
in order to understand the progress and future 
directions of this rapidly moving area of science. 
Some of the important experimental methods 
including methods of cell and molecular biology 
will be discussed in this unit. 
Chapter 12.indd   279 09/01/2025   15:17:36
Reprint 2025-26
Frederick Sanger 
(1918-2013) 
Frederick Sanger (1918–2013) was 
a British biochemist and molecular 
biologist who had two Nobel Prizes 
in Chemistry to his credit. He was 
awarded the ??rst Nobel Prize in 
1958 for the discovery of structure 
of insulin molecule, and second 
Nobel Prize in 1980 for his work (in 
collaboration with Paul Berg and 
Walter Gilbert) on the determination 
of base sequences of nucleic acids. 
He is, by far, the most in??uential 
biochemist in history. His technique 
of deciphering DNA sequences 
was based on ‘read-off’ methods 
using acrylamide gel. In 1977, 
Sanger sequenced the genome of 
bacteriophage FX174, the ??rst 
genome to be completely sequenced. 
Most of his later contributions laid 
the foundation of molecular biology 
and are being utilised in every 
biotechnology application. 
Chapter 12.indd   280 09/01/2025   15:17:38
Reprint 2025-26
Page 3


Tools and 
Techniques: 
Basic Concepts
Unit V
Chapter 12 
Tools and Techniques
Considering the fact that biotechnology is 
an experimental science and involves a lot of 
experimentations; therefore, research in this ??eld 
depends highly on sophisticated laboratory methods. 
Advances in biotechnology were closely followed by 
the development of newer tools and techniques in 
biological sciences. These new methods opened new 
avenues for research and investigation in the ??eld 
of biotechnology. It is, thus, important to appreciate 
the experimental tools available to biotechnologists 
in order to understand the progress and future 
directions of this rapidly moving area of science. 
Some of the important experimental methods 
including methods of cell and molecular biology 
will be discussed in this unit. 
Chapter 12.indd   279 09/01/2025   15:17:36
Reprint 2025-26
Frederick Sanger 
(1918-2013) 
Frederick Sanger (1918–2013) was 
a British biochemist and molecular 
biologist who had two Nobel Prizes 
in Chemistry to his credit. He was 
awarded the ??rst Nobel Prize in 
1958 for the discovery of structure 
of insulin molecule, and second 
Nobel Prize in 1980 for his work (in 
collaboration with Paul Berg and 
Walter Gilbert) on the determination 
of base sequences of nucleic acids. 
He is, by far, the most in??uential 
biochemist in history. His technique 
of deciphering DNA sequences 
was based on ‘read-off’ methods 
using acrylamide gel. In 1977, 
Sanger sequenced the genome of 
bacteriophage FX174, the ??rst 
genome to be completely sequenced. 
Most of his later contributions laid 
the foundation of molecular biology 
and are being utilised in every 
biotechnology application. 
Chapter 12.indd   280 09/01/2025   15:17:38
Reprint 2025-26
12.1 Microscopy Biological studies and explorations cannot be imagined 
without a microscope as it enables us to see something 
which is beyond the scope of our eyes. Today, the technique 
of microscopy has become so much advanced that a 
researcher can not only see a highly magni??ed image of 
a very minute structure but also can visualise the three 
dimensional structure of such objects. Using powerful 
electron microscopic techniques, even the DNA molecule 
of bacteria and viruses have been visualised.
The use of ??rst microscope dates back to 1665 when 
the British physicist Robert Hooke designed a simple 
microscope using combination of magnifying lenses (Fig. 
12.1) and observed the slices of cork, and coined the term 
‘Cellulae’ or ‘cell’ to that honeycomb like structure. You 
are aware that Matthias Jacob Schleiden and Theodor 
Schwann proposed cell theroy in 1838 on the basis of 
observation of cells in plants and animals. 
12.1 Microscopy
12.2 Centrifugation
12.3 Electrophoresis
12.4 Enzyme-linked 
Immunosorbent 
Assay (ELISA)
12.5 Chromatography 
12.6 Spectroscopy
12.7 Mass Spectrometry
12.8 Fluorescence in situ 
hybridisation (FISH)
12.9 DNA Sequencing
12.10 DNA Microarray
12.11 Flow Cytometry
Tools and 
Techniques
Chapter 12
Chapter 12.indd   281 09/01/2025   15:17:38
Reprint 2025-26
Page 4


Tools and 
Techniques: 
Basic Concepts
Unit V
Chapter 12 
Tools and Techniques
Considering the fact that biotechnology is 
an experimental science and involves a lot of 
experimentations; therefore, research in this ??eld 
depends highly on sophisticated laboratory methods. 
Advances in biotechnology were closely followed by 
the development of newer tools and techniques in 
biological sciences. These new methods opened new 
avenues for research and investigation in the ??eld 
of biotechnology. It is, thus, important to appreciate 
the experimental tools available to biotechnologists 
in order to understand the progress and future 
directions of this rapidly moving area of science. 
Some of the important experimental methods 
including methods of cell and molecular biology 
will be discussed in this unit. 
Chapter 12.indd   279 09/01/2025   15:17:36
Reprint 2025-26
Frederick Sanger 
(1918-2013) 
Frederick Sanger (1918–2013) was 
a British biochemist and molecular 
biologist who had two Nobel Prizes 
in Chemistry to his credit. He was 
awarded the ??rst Nobel Prize in 
1958 for the discovery of structure 
of insulin molecule, and second 
Nobel Prize in 1980 for his work (in 
collaboration with Paul Berg and 
Walter Gilbert) on the determination 
of base sequences of nucleic acids. 
He is, by far, the most in??uential 
biochemist in history. His technique 
of deciphering DNA sequences 
was based on ‘read-off’ methods 
using acrylamide gel. In 1977, 
Sanger sequenced the genome of 
bacteriophage FX174, the ??rst 
genome to be completely sequenced. 
Most of his later contributions laid 
the foundation of molecular biology 
and are being utilised in every 
biotechnology application. 
Chapter 12.indd   280 09/01/2025   15:17:38
Reprint 2025-26
12.1 Microscopy Biological studies and explorations cannot be imagined 
without a microscope as it enables us to see something 
which is beyond the scope of our eyes. Today, the technique 
of microscopy has become so much advanced that a 
researcher can not only see a highly magni??ed image of 
a very minute structure but also can visualise the three 
dimensional structure of such objects. Using powerful 
electron microscopic techniques, even the DNA molecule 
of bacteria and viruses have been visualised.
The use of ??rst microscope dates back to 1665 when 
the British physicist Robert Hooke designed a simple 
microscope using combination of magnifying lenses (Fig. 
12.1) and observed the slices of cork, and coined the term 
‘Cellulae’ or ‘cell’ to that honeycomb like structure. You 
are aware that Matthias Jacob Schleiden and Theodor 
Schwann proposed cell theroy in 1838 on the basis of 
observation of cells in plants and animals. 
12.1 Microscopy
12.2 Centrifugation
12.3 Electrophoresis
12.4 Enzyme-linked 
Immunosorbent 
Assay (ELISA)
12.5 Chromatography 
12.6 Spectroscopy
12.7 Mass Spectrometry
12.8 Fluorescence in situ 
hybridisation (FISH)
12.9 DNA Sequencing
12.10 DNA Microarray
12.11 Flow Cytometry
Tools and 
Techniques
Chapter 12
Chapter 12.indd   281 09/01/2025   15:17:38
Reprint 2025-26
282
Biotechnology 12.1.1 Magni??cation and Resolution
Let us now focus on the principle on which the technique of 
microscopy is based. Two optical properties are extremely 
important for an optical instrument like microscope. One is 
the power to magnify and the other is the ability to resolve. 
Magni??cation or magnifying power of a microscope is 
the ability by which the retinal image size can be increased. 
Thus in simple terms magni??cation is—
Size of retinal image with the help of microscope
__________________________________________________
Size of the retinal image without using microscope
You may have studied in physics that magni??cation (M) of 
a lens is measured as per the following formula (in which 
f is focal length of the lens and d is the distance of object 
from the lens).
Fig. 12.1: Microscope
Revolving nose
piece
Objective
Condenser
Stage
Sub stage
Mirror
Base
Inclination joint
Coarse adjustment
knob
Fine adjustment
knob
Body tube
Eyepiece
Arm
M = 
f
f-d
Chapter 12.indd   282 09/01/2025   15:17:38
Reprint 2025-26
Page 5


Tools and 
Techniques: 
Basic Concepts
Unit V
Chapter 12 
Tools and Techniques
Considering the fact that biotechnology is 
an experimental science and involves a lot of 
experimentations; therefore, research in this ??eld 
depends highly on sophisticated laboratory methods. 
Advances in biotechnology were closely followed by 
the development of newer tools and techniques in 
biological sciences. These new methods opened new 
avenues for research and investigation in the ??eld 
of biotechnology. It is, thus, important to appreciate 
the experimental tools available to biotechnologists 
in order to understand the progress and future 
directions of this rapidly moving area of science. 
Some of the important experimental methods 
including methods of cell and molecular biology 
will be discussed in this unit. 
Chapter 12.indd   279 09/01/2025   15:17:36
Reprint 2025-26
Frederick Sanger 
(1918-2013) 
Frederick Sanger (1918–2013) was 
a British biochemist and molecular 
biologist who had two Nobel Prizes 
in Chemistry to his credit. He was 
awarded the ??rst Nobel Prize in 
1958 for the discovery of structure 
of insulin molecule, and second 
Nobel Prize in 1980 for his work (in 
collaboration with Paul Berg and 
Walter Gilbert) on the determination 
of base sequences of nucleic acids. 
He is, by far, the most in??uential 
biochemist in history. His technique 
of deciphering DNA sequences 
was based on ‘read-off’ methods 
using acrylamide gel. In 1977, 
Sanger sequenced the genome of 
bacteriophage FX174, the ??rst 
genome to be completely sequenced. 
Most of his later contributions laid 
the foundation of molecular biology 
and are being utilised in every 
biotechnology application. 
Chapter 12.indd   280 09/01/2025   15:17:38
Reprint 2025-26
12.1 Microscopy Biological studies and explorations cannot be imagined 
without a microscope as it enables us to see something 
which is beyond the scope of our eyes. Today, the technique 
of microscopy has become so much advanced that a 
researcher can not only see a highly magni??ed image of 
a very minute structure but also can visualise the three 
dimensional structure of such objects. Using powerful 
electron microscopic techniques, even the DNA molecule 
of bacteria and viruses have been visualised.
The use of ??rst microscope dates back to 1665 when 
the British physicist Robert Hooke designed a simple 
microscope using combination of magnifying lenses (Fig. 
12.1) and observed the slices of cork, and coined the term 
‘Cellulae’ or ‘cell’ to that honeycomb like structure. You 
are aware that Matthias Jacob Schleiden and Theodor 
Schwann proposed cell theroy in 1838 on the basis of 
observation of cells in plants and animals. 
12.1 Microscopy
12.2 Centrifugation
12.3 Electrophoresis
12.4 Enzyme-linked 
Immunosorbent 
Assay (ELISA)
12.5 Chromatography 
12.6 Spectroscopy
12.7 Mass Spectrometry
12.8 Fluorescence in situ 
hybridisation (FISH)
12.9 DNA Sequencing
12.10 DNA Microarray
12.11 Flow Cytometry
Tools and 
Techniques
Chapter 12
Chapter 12.indd   281 09/01/2025   15:17:38
Reprint 2025-26
282
Biotechnology 12.1.1 Magni??cation and Resolution
Let us now focus on the principle on which the technique of 
microscopy is based. Two optical properties are extremely 
important for an optical instrument like microscope. One is 
the power to magnify and the other is the ability to resolve. 
Magni??cation or magnifying power of a microscope is 
the ability by which the retinal image size can be increased. 
Thus in simple terms magni??cation is—
Size of retinal image with the help of microscope
__________________________________________________
Size of the retinal image without using microscope
You may have studied in physics that magni??cation (M) of 
a lens is measured as per the following formula (in which 
f is focal length of the lens and d is the distance of object 
from the lens).
Fig. 12.1: Microscope
Revolving nose
piece
Objective
Condenser
Stage
Sub stage
Mirror
Base
Inclination joint
Coarse adjustment
knob
Fine adjustment
knob
Body tube
Eyepiece
Arm
M = 
f
f-d
Chapter 12.indd   282 09/01/2025   15:17:38
Reprint 2025-26
283
t ools and t echnologies : Basic c oncepts Normally, the microscope which is used in the laboratory 
is a compound microscope in which two sets of lenses are 
there. One is called objective lens, which remains close to 
the object to be seen, and the other is eyepiece through 
which the observer sees. It is needless to mention that the 
object, objective lens, eyepiece, and the eye of the observer 
have to be in the same line for the passage of light to 
see the magni??ed image of the object. In simple words, 
magni??cation of a microscope is product of the magnifying 
power of the objective lens and the magnifying power of 
the eyepiece (M
o
 × M
e
). 
Resolving power is another important property of a 
microscope, which is the ability to form separate images 
of the two objects situated very close to each other. It can 
be measured by the smallest distance between two points.
12.1.2 Functioning of a light microscope
You have already studied about the structure of a compound 
microscope in previous class, yet to recapitulate, as you 
can see in the Fig. 12.1, a compound microscope consists 
of a base on which a stage is ??tted with a central hole. 
Attached to the base is an arm to which a body tube is ??tted 
in such a way that it aligns with the hole of the stage. At the 
lower end of the body tube, a nose piece is ??tted on which 
two to four objective lenses may be present. By rotating the 
nose piece, one of the objective lenses can be placed above 
the hole present on the stage where object to be seen is 
placed on a glass slide. At the upper end of the body tube, 
an eye piece is ??tted through which an observer can see 
under the microscope. There are adjustment screws (coarse 
and ??ne) on the arm which facilitate in adjusting the 
distance of objective lens from the object present on the 
stage. Below the stage, there is a source of light (which may 
be a re??ective mirror or a bulb to illuminate the object and 
facilitate the formation of image through objective lens and 
eyepiece) (Fig. 12.2). In addition, there is a condenser 
present between the light source and the stage, which is 
important for focusing light on the object. You might have 
observed that both objective lenses and eye pieces are of 
different magnifying power. In a student microscope the 
eyepiece has the magnifying power of 10 × or 15 × and that 
of the different objective lenses ??tted on the nose piece are 
of 4 ×, 10 ×, 40/45 × and 100 ×. The technique of microscopy 
Chapter 12.indd   283 09/01/2025   15:17:38
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