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SUBODH PUBLIC SCHOOL,RAMBAGH
SESSION 2020-21
CLASS –Scholars 1
SUBJECT -Biotechnology
ONLINE ASSIGNMENTS (April 27 to May 16, 2020)
UNIT I: Biotechnology : An Overview
Name of Book : A Text Book of Biotechnology for class XI
Author/Publisher : C.B.S.E. New Delhi
Link for e book:
http://agitsolution.com/cbse/ebooks/11TH%20CLASS/Biotechnology-
Textbook/unit-1.pdf
https://evirtualguru.com/biotechnology-ebook-for-class-11-cbse-ncert/
For any query/doubts: Whatsapp number: 9413344952 (Dr. Manish Jain)
Important Instructions:
1. Dear learners kindly go through the content as per guidelines given date-wise.
2. kindly note down your query and please WhatsApp me on my number given above.
3. It is mandatory to go through the content as per guidelines.
4. All worksheets and practice tests can be done on A4 size paper and can be submitted to me on
reopening of school.
5. Regularly attend Online Virtual Classes (Zoom) as per time table
LEARNING OUTCOMES
The Learner
1. Students will be able to know about biotechnology as subject.
2. They will be able to know that how this is so important in coming 21 century,
its Indian Scenario and Global scenario.
3. About historical aspects of Biotechnology and its implementation and its utility
in past
4. Students will be able to differentiate between Classical Biotechnology and
Modern Biotechnology.
5. Students will able to know about various applications of Biotechnology in
various fields.
6. Students will be able to evaluate its importance in terms of economical
statistical data related with Biotechnogy oin context to Indian and Global
Scenario.
APRIL 27,2020
BIOTECHNOLOGY: AN OVERVIEW 1 Overview
Modern biotechnology has integrated several disciplines, varying from physics,
chemistry, mathematics, biology, engineering, economics, law and
management. The extraordinary developments occurring in biotechnology
throughout the world has lead to significant changes in world commerce, as well
as in human healthcare and agriculture sectors. Production of vaccines
employing recombinant DNA methods is one example of its potential application.
Pharmacologically active compounds from plants and marine organisms can now
be isolated effectively using biotechnology. Progress in agricultural biotechnology
will make our society less dependent on sustained harvest, which is often
subjected to the vagaries of weather or climate.
This chapter makes you familiar with the developments in biotechnology field and
its applications in health care and agriculture.
1 Chapter 1
The development of technologies that use living organisms or substances derived
from them for the benefit of mankind led to the establishment of field of
biotechnology. Thus, biotechnology is now defined as “Any technological
application that uses biological systems, living organisms or derivatives thereof to
make or modify products or processes for specific uses” (Food and Agriculture
Organization). Humans have for centuries practiced biotechnology. They have
used biotechnology to make bread, cheese, and beers and wines, to breed
strong and productive animals, and to increase the yield of crops by selecting
seeds from particularly desirable plants. The modern biotechnology is based on
the fundamental knowledge of biosciences and thus, truly interdisciplinary in
nature (Fig. 1). It has already made its presence felt in our daily life in many ways
and now providing new opportunities for career advancement.
1.1 Historical Perspectives
The making of curd, bread, wine, and beer originated in prehistoric kitchens and
the process leading to the development of these products came to be known as
fermentation. Around 2000 BC, the Egyptians knew that when crushed dates
were stored, a pleasantly intoxicating material was produced at first but if the
mixture was allowed to stand for a longer time, it turned sour to yield vinegar, the
strongest acid known to antiquity. By 1500 BC, the use of germinated cereals
(malt) for the preparation of beer from bread leaven (a mass of yeast) on a cereal
dough and the formation of wine from crushed grapes, were established as
technical arts in Mesopotamia, Palestine and Egypt. The ancients also observed
that the formation of beer, wine or vinegar was followed by changes that led to
the liberation of noxious odours, thus showing putrefaction for plant materials as
compared to the more rapid decay of animal or human tissues. The practical
arts of preserving animal foods – drying, smoking, curing, pickling in brine, and
treatment with granular salt -- were well developed in the prehistoric Near East
and Europe. The well-known mummification procedures in Egypt used the
technique of dehydration with a mixture of salts, largely sodium carbonate.
By18th century it was observed that fermentation could be classified into
three groups on the basis of final products:
1. Evolution of gas
2. Formation of alcohol, and
3. Production of acid
Antoine Lavoisier provided the chemical basis for the nature of alcoholic
fermentation by using analytical techniques for the quantitative estimation of
carbon.
Worksheet No 17
Q1. Define biotechnology
Q2. How humans have for centuries practiced biotechnology. ?
Q3. On what factors the modern biotechnology is based on ?
Q4. Write a short note on historical perspectives
Q5. How fermentation could be classified on the basis of final products:
Q6. Who provided the chemical basis for the nature of alcoholic fermentation by using
analytical techniques for the quantitative estimation of carbon.
Q7. Explain the interdisciplinary nature of Biotechnology
APRIL 28,2020
1.1.1 Microorganisms as causative agents of fermentation
In the early 19th century, Nicolas Appert, a French manufacturer of confectionery who
distilled spirits and food products, described methods for preserving foods by putting
them into tightly closed vessels that were then heated in boiling water – this marked the
beginning of the canning industry.
Gay Lussac examined Appert’s closed heated vessels and found that they lacked
oxygen. This led to the belief that oxygen was necessary for fermentation.
The construction of achromatic compound microscope demonstrated in 1837 that the
agents of fermentation are living organisms.
Charles Cagniard–Latour in 1838 described the involvement of brewer’s yeast in
alcoholic fermentation based on:
(i) its constant occurrence in fermentation,
(ii) cessation of fermentation under the conditions that killed yeast, such as
boiling, treatment with arsenate, etc. and
(iii) it was evoked and increased by the process itself - a phenomenon that
applies to living organisms only.
In 1857, Louis Pasteur published his first report on formation of lactic acid from sugar
through fermentation. It was already known that lactic acid is produced from sugar and
that addition of chalk to fermentation mixture markedly increases the amount of lactic
acid produced. Using a microscope, Pasteur showed the presence of lactic yeast,
which is the agent for the making of curd and confirmed the presence of L-lactic
acid using a polarimeter. In 1860, he presented a detailed report on alcoholic
fermentation and concluded:
The act of fermentation is a phenomenon, which is unique, and very
complex, as it can be a phenomenon correlated with life, giving rise to
multiple products such as succinic acid, glycerin etc. all of which are
necessary.
There is never any alcoholic fermentation without there being simultaneously
the organization, development, and multiplication of the globules which are
already formed.
He held the same views on lactic fermentation, butyric fermentation,
fermentation of tartaric acid etc.
He did not comment on the chemical act of cleavage of the sugar.
Fermentation appears to be a physiological phenomenon.
Fermentation is a consequence of anaerobic life.
Our ancestors have developed their own kitchen technologies with the help of fermenting
bacteria, like Lactobacillus, Leuconostoc, Lactococcus, Enterococcus, Pediococcus etc
leading to the development of a wide variety of yummy dishes that we relish today (Table 1). The
preparation of curd is a household recipe known to us for centuries. You too can prepare curd
using the following mother’s recipe (Fig. 2):
MAKING OF THE CURD Have you observed your mother making curd at home? Depending on the size of
the family and average consumption, she has arrived at her own quantitative
approach. Assuming a family of four consumes 200 ml/person of curd, she takes
800-1000 ml of milk, warms/cools it to lukewarm temperature (~37oC). Then she
takes a teaspoon of the previous day’s curd and distributes it uniformly in one liter
of milk by stirring it. Assuming that it is a warm summer day, the curd is ready in
about four hours.
Observations
The raw material, milk, has been converted completely into a semisolid
product in four hours by addition of only one teaspoon of curd.
The raw material, a white homogeneous slightly sweet liquid, has been
converted into a semisolid, sour tasting product.
There appears to be both a physical as well as a chemical change during
the process.
The 19th century saw the growth of industries linked to fermentation, which gave
rise to products like wine, beer, and whisky. This period also saw the growth of
canned food industry, which helped in the preservation of food for a longer time
and made them available during off-seasons. The fermentation industry along
with agricultural practices of animal husbandry and plant hybridization led to the
shifting of attention from agriculture to industry.
The 20th century saw man develop the ability to conquer several diseases thanks
especially to the antibiotic revolution in the 1940s. The antibiotic revolution
demanded large-scale production to meet the challenging demand of the health
sector. This resulted in a shift from kitchen technologies to large-scale
manufacturing in an industrial sector. And this further led to close interaction
between fermentation scientists and engineers from various disciplines of
engineering, which gave rise to branches like bioprocess engineering, food
science engineering and technology, bio-expert system engineering and artificial
neural networks, validation engineering, metabolic engineering and environment
management.
TABLE 1. TRADITIONAL LACTIC-FERMENTED FOODS OF INDIA
Food Substrate Nature and use
Traditional fermented products of south India
Idli Rice-black gram Steamed, spongy cake; breakfast food
Dosa Rice-black gram Spongy pan cake, shallow-fried; staple food
Ambali Millet, rice Steamed cake; staple food
Traditional fermented products of north India
Bhallae Black gram Deep-fried patties; snack
Vadai Black gram Deep-fried; snack
Papad Black gram Circular wafers; snack
Wari Black gram Spongy cake; snack
Bhatura Wheat Flat deep-fried, leavened bread; snack
Nan Wheat Leavened flat backed bread; staple food
Jalebi
Wheat
Crispy, deep fried pretzel; sweet confectionery
Paneer
Milk
Soft milk-flavored cheese; fried curry
Dahi
Milk
Thick-gel, savory
Traditional fermented products of western regions of India
Dhokla
Bengal gram
Spongy cake; snack
Khaman
Bengal gram
Spongy cake; breakfast food
Rabadi
Wheat/Pear-
millet/Barley-
Buttermilk mixture
Cooked paste; staple food
Srikhand
Milk
Concentrated sweetened, savory
Indigenous fermented products of eastern regions of India
Mishti dahi
Milk
Thick gel; sweet savory
Tari
Date palm
Sweet cloudy white alcoholic beverage
Traditional fermented products of the Himalayas
Gundruk
Leafy vegetable
Sun-dried, sour-acidic taste; soup/pickles
Sinki
Radish tap root
Sun-dried, sour-acidic taste; soup/pickles
Mesu
Bamboo shot
Sour-acidic, pickles
Khalpi
Cucumber
Sour, pickles
Chhurpi
Milk
Soft mass, cheese-like, mild sour; curry
Worksheet No 18
Q1. Who described methods for preserving foods by putting them into tightly closed
vessels that were then heated in boiling water
or
Who's method of preserving food has marked the beginning of the canning industry.
Q2. Which scientist examination with Appert’s closed heated vessels, founded that they
lacked oxygen.
Or
Who's experimentation has led to the belief that oxygen was necessary for fermentation.
Q3. Who described the involvement of brewer’s yeast in alcoholic fermentation
Q4. Who published first report on formation of lactic acid from sugar through
fermentation.
Q5. Which instruments did pasteur used the presence of lactic yeast and the presence of
L-lactic acid.
Q6. Name some of the fermenting bacteria, used in development of a wide variety of
yummy dishes that we relish today
Q7. When did antibiotic revolution started and how its demanded large-scale
production to meet the challenging demand of the health sector.
Q8. Give some examples of traditional fermented products of India
April 29, 2020
1.2. Technology and applications of Biotechnology
The current excitement about modern biotechnology is due to the manner in
which this science has pushed organisms beyond their natural abilities by genetic
engineering and hybridoma technology. Nature has equipped every organism
with the capacity to perform within an optimum or balanced system. Some of the
common Living systems with industrial applications are listed in Table 2. Modern
biotechnology has tinkered with the genetic material of the organism by
introducing foreign genes. The purpose is to push the organism to do things it
never did before. Ability to genetically manipulate organisms right from viruses to
mammals led to the genomics revolution – touted as the third technological
revolution following the industrial and computer revolutions. For example, study
of genomics has helped not only in determining the entire gene sequence but
also making fine-scale genetic maps of organisms. Bioremediation technologies
are used to clean our environment by removing toxic substances from
contaminated soils and ground water. Agricultural biotechnology has reduced our
dependence on pesticides. Manufacturing processes based on biotechnology has
made it possible to produce paper and chemicals with less energy, less pollution,
and less waste. Biotechnology has now found applications in virtually every
sphere of human activity (Table 3). Different technologies used in
biotechnology and their applications are as follows
Table 2. Living systems with Industrial applications Prokaryote
Eubacteria
Unicellular
Mycelial--Actinomycetes (Streptomyces, Nocardia)
Archaea (extremophiles) Eukaryote Fungi Yeast Mold Algae Protozoa Insect Cells Plant cells or Tissues, organs Animal cells, tissues and organs
Transgenic animal/Plant
1.2.1 Bioprocessing Technology
Bioprocess technology is the oldest in all the biotechnologies. Bioprocessing
technology, uses living cells or the molecular components to manufacture desired
products. The living cells most commonly used are one-celled microorganisms,
such as yeast and bacteria; the biomolecular components mostly used are
enzymes, which are proteins that catalyze biochemical reactions. Microbial
fermentation, is a form of bioprocess technology has been used for thousands of
years—unwittingly—to brew beer, make wine, leaven bread and pickle foods.
Now a day recombinant DNA technology coupled with microbial fermentation are
used to manufacture a wide range of biobased products including human insulin,
the hepatitis B vaccine, the calf enzyme used in cheese making, biodegradable
plastics, and laundry detergent enzymes.
1.2.2 Cell Culture
Cell culture technology is the growing of cells outside of living organisms. Cell
culture are of many types.
Plant Cell Culture: An essential step in creating transgenic crops, plant cell
culture also provides us with an environmentally sound and economically feasible
option for obtaining naturally occurring products with therapeutic value. Plant cell
culture is also an important source of compounds used as flavors, colors and
aromas by the food-processing industry.
Mammalian Cell Culture: Livestock breeding has used mammalian cell culture
as an essential tool for decades. Eggs and sperm, taken from genetically superior
bulls and cows, are united in the lab, and the resulting embryos are grown in
culture before being implanted in surrogate cows
1.2.3 Recombinant DNA Technology
Recombinant DNA technology is viewed as the cornerstone of biotechnology.
The term recombinant DNA means the joining or recombining of two pieces of
DNA from two different sources. Genetic modification using recombinant DNA
techniques allows us to move genes whose functions are known. By making
manipulations more precise and outcomes more certain, the risk of producing
organisms with unexpected traits are decreased. Recombinant DNA technologies
have various uses like research application, creation of genetically modified
variety of plants and animals.
Worksheet No 19
Q1. How modern biotechnology has tinkered with the genetic material ?
Q2. How genomics revolution touted as the third technological revolution following
the industrial and computer revolutions.
Q3. Explain Bioremediation technologies.
Q4 Biotechnology has now found applications in virtually every sphere of human
activity. Discuss?
Q5. What is Bioprocessing Technology
Q6. How now a day recombinant DNA technology coupled with microbial
fermentation are used to manufacture a wide range of biobased products
Q7 How many types of Cell culture are there
Q8. How Recombinant DNA technology is viewed as the cornerstone of
biotechnology.
April 30, 2020
1.2.4 Cloning
Cloning technology allows us to generate a population of genetically identical
molecules, cells, plants or animals. Because cloning technology can be used to
produce molecules, cells, plants and some animals, its applications are
extraordinarily broad. Molecular or gene cloning is the process of creating
genetically identical DNA molecules. Molecular cloning is foundation of the
molecular biology and is a fundamental tool of biotechnology research,
development and commercialization. All applications in biotechnology, from drug
discovery and development to the production of transgenic crops, depend on
gene cloning.
Animal cloning has helped us to rapidly incorporate improvements into livestock
herds for more than two decades and has been an important tool for scientific
researchers. One of the technique used in animal cloning is Somatic cell nuclear
transfer (SCNT). It involves transfer of the nucleus of a somatic cell taken from an
adult female and transferred it to an egg cell from which the nucleus had been
removed. The resulting cell behaved like a freshly fertilized zygote, which
developes into an embryo.
1.2.5 Protein Engineering
Protein engineering technology involves improvement of existing proteins, such
as enzymes, antibodies and cell receptors, and to create proteins not found in
nature. This technique is used in conjunction with recombinant DNA techniques.
Such engineered proteins are used in drug development, food processing and
industrial manufacturing.
1.2.6 Biosensors
Biosensor technology couples the knowledge of biology with microelectronics. A
biosensor is composed of a biological component, such as a cell, enzyme or
antibody, linked to a tiny transducer—a device powered by one system that then
supplies power (usually in another form)
to a second system. Biosensors are detecting devices that rely on the specificity
of cells and molecules to identify and measure substances at extremely low
concentrations. When the substance of interest binds with the biological
component, the transducer produces an electrical or optical signal proportional to
the concentration of the substance. Biosensors can be used for; measurement of
nutritional value, freshness and safety of food; location and measurement of
environmental pollutants.
1.2.7 Nanobiotechnology
The word nanotechnology derives from nanometer, which is one-thousandth of a
micrometer (micron), or the approximate size of a single molecule.
Nanotechnology is the study, which involves manipulation and manufacture of
ultra-small structures and machines made of as few as one molecule.
Nanobiotechnology uses the knowledge of nanotechnology and biomolecules of
cell to produce desired technology. Some applications of nanobiotechnology
includes; fast diagnosis of disease, bio-nanostructures creation for getting
functional molecules into cells, improvement of specificity and timing of drug
delivery.
Worksheet No 20
Q1. What is Cloning technology ?
Q2. Explain one of the technique Somatic cell nuclear transfer (SCNT) used in animal
cloning.
Q3. What is Protein Engineering
Q4. How engineered proteins are used in drug development, food processing and
industrial manufacturing.
Q5. How Biosensor technology couples the knowledge of biology with microelectronics.
Q6. Explain important uses of Biosensors
Q7. What is Nanobiotechnology and write some applications of nanobiotechnology
May 01,2020
Table 3. Applications of Biotechnology
Health Industry
Protein pharmaceuticals
Vaccine and Therapeutic agents
Diagnostics (Protein- or DNA)
Gene Therapy
Agriculture Industry
o Biopesticides/ Biofertilizers o Crops tolerant to abiotic and biotic stresses-
o Pharmaceutical production
Chemical Industry
Fermentation process to produce organic chemicals Production of high purity chemicals Use of energy efficient processes
Cleaning Industry
Use of enzymes as detergents like proteases Textile Industry
Use of enzymes for finishing of fabrics Use of genetically-modified cotton
Pulp and Paper Industry
Improvement of physical properties of fibers\ Biobleaching of pulp
The advent of the 21st century has witnessed the:
Mapping of genomes of many plant and animal species including humans,
Cloning of animals including many higher mammals,
Development of target-specific new molecules and drugs,
Stem cell therapy for genetic diseases and accident cases,
Tissue engineering for producing artificial tissues and organs ,
Creation of transgenic animals and plants for the production of
recombinant biopharmaceuticals,
Emergence of bioinformatics and computational biology in understanding
the functioning of cells and organs at genomic and protein levels etc.,
Application of in-silico experiments to understand pharmacology, toxicity
etc.,
Development of automated gene and protein sequencing
Identification of proteins and peptides by mass spectrometry,
Evolution of nanotechnology and its application in nanomedicine, and
Growth of RNA interference biology
Worksheet No 21
Q1. What are the applications of Biotechnology
Q2. Explain the role of Biotechnology in various fields as
a) Health Industry
b) Agriculture Industry
c) Chemical Industry
d) Cleaning Industry
e) Textile Industry
f) Pulp and Paper Industry
Q3. What has witnessed the advent of the 21st century in field of Biotechnology
May 02,2020
1.3 Global Market of Biotech Products
The biotechnology industry is also improving lives through its substantial
economic impact. Biotechnology has stimulated the creation and growth of small
business, generated new jobs, and encouraged agricultural and industrial
innovation. In USA, the industry currently employs over 150,000 people and
invests ~ $10 billion a year on research and development (Table 4).
Table 4. U.S. biotechnology product sales forecast (Value in $ million)
Modern biotechnology products started coming into the market only in the late
1980s. Globally, the share of biotechnology in the pharmaceutical market was
less than 0.14% in 1985. By 2000 this share grew to 20%. Today, about 60% of
the biotechnology products in the market are healthcare products (Table 5).
About 21% of the biotechnology products go into agriculture and animal
husbandry. The commonly sought after agronomic traits for plants are given in
Table 6. Given that there are some crucial questions that have remained
unanswered so far (for example, how a bacterially produced human protein would
acquire the same three-dimensional structure as found in the human system?),
remain a challenge and enigma for biotechnologists.
Key sectors
Base year
1998 Forecast year 2003
Forecast year 2008
Human therapeutics
9,120
16,100
27,000
Human diagnostics
2,100
3,100
4,300
Agriculture
420
1,000
2,300
Specialties
390
900
2,000
Non-medical diagnostics
270
400
600
Mammalian Cells
Hybridomas, Myeloma
Monocional Antibodies, recombinant antibodies
Chinese Hamster Ovary, Baby Hamster Kidney
Cell Lines
Interferon, tissue plasminogen (tPA) activator, erythropoietin
(EPO)
Human Kidney 293 Cell Lines
Adenovirus for gene therapy
Human lung fibroblast MRC-5
Attenuated hepatitis C virus
Monkey Kidney epithelial cell Vero
Inactivated polio virus
Mammalian Cells stem cells
Tissue regeneration Gene therapy Preclinical disease
models
Bacteria
Escherichia coli
Insulin, human growth Hormone, somatostatin, interferon,
Bovine growth hormone
Yeast
Saccharomyces cerevisiae
Hepatitis B virus surface antigen (vaccine against Hepatitis
B)
Table 6. Agronomic traits from Biotechnology
Herbicide tolerance
Insect resistance
Disease resistance
Abiotic stress, e.g., Water, Temperature, Salt, Metals
Value added traits, e.g., Oil, Vitamins, Minerals
Nutritional quality, e.g., proteins, fats, carbohydrate; Plant properties, e.g., shelf-life,
flavors fragrance
Allergen reduction
Nitrogen fixation
Yield
Pharmaceutical production, e.g., Vaccines, Proteins
2001: GMO 130 MM acres (75% U.S.),
e.g., cotton, soybean, corn, canola, rice ________________________________________________________
Overall Benefits : Less cost / acre, More yield, Less pollution
1.4 Public Perception of Biotechnology
The public demands that biotechnology should work for the benefit of the society.
This entails major changes in the sciences and the social sciences. But these
changes are not possible without active societal participation. The participation of
the society has become all the more important because of the realization of the
environmental consequences of science and technology. A technology is
democratic if it has been designed and chosen with democratic participation.
Participation in scientific research decision-making and policy-making, in general,
requires certain discretion and deliberative capabilities on the part of the citizens.
Civil society organizations (CSOs) have inherent advantages in handling
information (on social, economic and ecological variables and processes) and
controlling decision processes. The debate about the relative merits of
representative participation and direct democratic participation of the individual in
environmental decisions remains unresolved. It is argued that representative
participation may be the solution for the time being, because detailed debates on
technology or the ‘technology tribunals’ work only in contexts where there are
literate and informed public and a liberal democratic government. Therefore, the
participation should begin at all levels of decision-making so that the society
could have better and more informed citizens.
While developments in science and technology are instrumental in most of our
progress, some genuine concerns have been raised regarding the long-term
consequences on our health and environment. In 1985, the UN assembly created
the Brundtland Commission also called WCED (World Commission on
Environment and Development). The commission submitted a report on the
theme of sustainable development. It recognized that there is a real conflict
between meeting the needs and desires of 6 billion people living today and the
possibility of satisfying the ten billion people expected to inhabit the Earth by
2050!!
The WCED defined Sustainable Development as follows:
“Sustainable development is development that meets the needs of the present
without compromising the ability of future generations to meet their own needs.”
Definitions of sustainable development are abundant and are interpreted in
varying manner by different nations. In all these definitions and the way they have
been implemented, science and technology is invariably portrayed as a double-
edged sword. A heated debate is taking place globally over the issue of GM
crops. This debate, which features science, economics, politics and even religion,
is taking place almost everywhere. Similar is the case with embryonic stem cell
research and its funding.
Worksheet No 22
Q1. The biotechnology industry is also improving lives through its substantial economic
impact, Discuss
Q2. Globally discuss the share of biotechnology in various fields
Q3. Give some examples of Agronomic traits which can be developed from
Biotechnology
Q4. What are the Public Perception of Biotechnology
Q5. Why the participation of the society has become all the more important because of
the realization of the environmental consequences of science and technology.
Q6. While developments in science and technology are instrumental in most of our
progress, some genuine concerns have been raised regarding the long-term
consequences on our health and environment. Share your views.
Q7. In 1985, the UN assembly created Which commission also called WCED on
concerns whichhave been raised regarding the long-term consequences of sciences on
our health and environment.
Q8. Write full form of WCED
Q9. Give definition of Sustainable development
Q10. What debate, which features science, economics, politics and even religion, is
taking place almost everywhere due to development in field of science specially
Biotechnology
May 03,2020
HOLIDAY
May 04,2020
1.5 Biotechnology in India and Global Trends
1.5.1 Indian scenario
The Indian response to the biotechnology industry and its products has been very
supportive right from the early 1980s when the investments in the Department of
Biotechnology (DBT) (http://dbtindia.nic.in) and other research and development
avenues were actively promoted. The Government has set up a Technology
Development Board to promote product development with universities, industries
and national institutes. Vision 2020 document has been prepared by Technology
Information, Forecasting and Assessment Council (TIFAC), which also includes
biotechnology. Indigenously developed Hepatitis B vaccine has been developed,
manufactured and marketed since 1998. There are nearly 30 companies devoted
to development of modern biotechnology products in India. Currently, India’s
share in the global biopharmaceutical market is just 1.5% and is valued at US $
1.05 billion. By registering a high growth rate of ~32 per cent in recent years,
India is poised to become a major player in the coming years.
1.5.2 Global scenario
The present global biopharmaceutical industry is valued at US $ 71 billion. With
the present growth rate of 16 per cent, it is likely to cross $ 100 billion mark by
the year 2010. USA promotes biotechnology enterprise by gearing up the
administration to develop policies, which will foster biotechnology innovations as
expeditiously and prudently as possible. There has been steady increase in
support for basic scientific research at the National Institutes of Health (NIH) and
other science agencies. The process of approving new medicines, making them
available and encouraging private-sector research investment and small business
development are being accelerated through new tax incentives and small
business innovations research program. The Government promotes intellectual
property protection and open international markets for biotechnology inventions
and products; and developed public databases that enable scientists to
coordinate their efforts in an enterprise that has become one of the world’s finest
examples of partnership among university-based researchers, government and
private industry. In addition, the administration has strengthened efforts to
improve science education and promote the freedom of scientific enquiries. It has
also provided guidelines to protect patients from the misuse or abuse of sensitive
medical information and provide Federal regulatory agencies with sufficient
resources to maintain sound, science-based review and regulation of
biotechnology products. It has also ensured that science-based regulatory
programs worldwide promote public safety, earn public confidence and guarantee
fair and open international markets. The European and the US biotechnology
industries both have around 2000 companies, but the US sector employs nearly
twice as many people, spends around three times as much on research and
development, has twice the number of employees involved in research and
development. It also earns twice as much revenue compared to the European
counterpart.
Worksheet No 23
Q1. Discuss the role of Biotechnology in context to Indian scenario and the Indian
response to the biotechnology industry and its products
Q2. Which indigenous vaccine is developed, manufactured and marketed since 1998 in
India.
Q3. How India is poised to become a major player in the coming years in field of
Biotechnology.
Q4. Discuss the Global scenario in context to field of Biotechnology.
May 5,2020
Worksheet No 24 (Final Revision)
Review Questions
1. Do you agree that your grandmother unknowingly practiced a technique of
biotechnology? Describe the technique.
2. What are the two instruments Louis Pasteur used to show the presence of
lactic yeast and L-lactic acid?
3. Name four traditional fermented foods of India.
4. Name some of the living systems that are being used for the industrial
applications.
5. List the important applications of biotechnology in health care.
6. List the important applications of biotechnology in agriculture.
7. Which was the first recombinant DNA-based product produced and marketed
in India?
May 6,2020
UNIT IV
Chapter 2222 CELL GROWTH AND DEVELOPMENT
web link for e-book
http://agitsolution.com/cbse/ebooks/11TH%20CLASS/Biotechnology-Textbook/unit-4.pdf
LEARNING OUTCOMES
The Learner
1. will be able to know the importance of cell divison.
2. Students will be able to know how the cell number increases and how cell division takes
place
3. they will be able to differentiate between two types of division and their scientific concept.
4. will be able to apply the knowledge of this division in various real life situations.
5. will be able to know about cell cycle and its regulation
6. will be able to know about various physiological processes of all living organisms.
7. Will be able to draw diagrams of mitosis, meiosis and antibody
8. will be able to learn about different types of reproduction in various organisms
(prokaryotes and eukaryotes)
4.2.1 Cell Division
Cell division is the process by which growth, repair and reproduction occurs in the living
organisms. Cell division is also responsible for distributing the genetic material among the
daughter cells. There are two main types of cell division - mitosis and meiosis. The main features
of both types are described below:
4.2.1.1 Mitosis
Mitosis is the process of nuclear division, which ensures that the daughter nuclei receive the
same number of chromosomes as the parent nucleus. It is usually followed by cytokinesis, a
process by which the cytoplasm is divided into two packages. Hence, the two daughter cells
resulting from mitosis and cytokinesis contain genetic information that is identical to each other
and also to the parent cell from which they are derived. The period between two successive cell
divisions is called interphase about which you shall read in the next section. Mitosis is usually
divided into five phases namely Prophase, Prometaphase, Metaphase, Anaphase and
Telophase. Each phase is characterized by specific events (Fig. 1).
4.2.1.1.1 Prophase
It is characterized by start of condensation of chromatin material to form compact chromosomes.
Each chromosome consists of two sister chromatids attached at the centromere. Centromere
houses a plate-like structure called the kinetochore, to which the microtubules of the spindle
attach. During prophase, the cytoskeleton dis-assembles and mitotic spindle begins to form from
the centriolar organizing centers. The disassembly of the nuclear envelope marks the end of the
prophase.
4.2.1.1.2 Prometaphase
At the beginning of prometaphase, microtubules of the spindles attach with the kinetochores of
the condensed chromosomes. Eventually, each chromosome is moved into position along a
plane at the centre of the spindle.
4.2.1.1.3 Metaphase
This phase is characterized by alignment of all the chromosomes at the equator of the spindle.
One chromatid of each chromosome is connected to a spindle fiber from one pole and its sister
chromatid is connected to a spindle fiber from the opposite pole. The plane of alignment of the
chromosomes at metaphase is referred to as the metaphase plate.
4.2.1.1.4 Anaphase
During anaphase the sister chromatids separate from each other and move towards opposite
poles.
4.2.1.1.5 Telophase
During telophase, the chromatids reach the opposite poles of the spindle. This is followed by
appearance of the nuclear envelope, the endoplasmic reticulum, Golgi complex and the
nucleolus. Also, the chromosomes uncoil to form the chromatin.
4.2.1.1.6 Cytokinesis
The nuclear division results in the segregation of the chromosomes into two daughter nuclei.
This is followed by cytokinesis. In animal cells, a cleavage furrow cuts the cytoplasm between
the two groups of separating chromatids. In plant cells, the cytoplasm is partitioned by the
construction of new cell wall - the cell plate, inside the cell. The process of cytokinesis appears to
be guided by organized bundles of actin filaments. Thus, at the end of the mitosis, the two
daughter cells receive identical copies of the genetic material.
Worksheet No 25
Q1. What is the basic role of process of Cell division
Q2. What are basically two main types of cell division
Q3. Which cell division ensures that the daughter nuclei receive the same
number of chromosomes as the parent nucleus.
Q4. The period between two successive cell divisions is called ?
Q5. Each chromosome consists of two sister chromatids which are
attached to which structure ?
Q6 What is the name of a plate-like structure in centromere to which the
microtubules of the spindle attach?
Q7. The plane of alignment of the chromosomes at metaphase is called ?
Q8. How does the process of Cytokinesis differs in Plants and animals in
term of process?
Q9. The process of cytokinesis appears to be guided by organized bundles
of which filaments.
Q10 Thus, at the end of the mitosis, how many daughter cells are formed.
Q11. Describe the different phases of mitosis with help of a well labelled
diagram.
May 7,2020
4.2.1.2 Meiosis
Meiosis involves two successive nuclear divisions. As a result of this, at the end of the meiosis,
four haploid cells are produced from a single diploid cell (Fig. 2). This process is essential for the
formation of gametes. Without meiosis, the gametes would have as many number of
chromosomes as other cells in the body, and number of chromosomes would double with each
new generation.
4.2.1.2.1 Meiosis I
The first meiotic division is divided into prophase I, metaphase I, anaphase I and telophase I.
The major events, which occur during each of these phases, are as follows:
4.2.1.2.2 Prophase I
The prophase I is very long and complex, and is usually divided into five sequential stages.
These are - Leptotene, Zygotene, Pachytene, Diplotene and Diakinesis. The leptotene stage is
characterized by the start of condensation of chromatin. During zygotene, the maternal and
paternal members of the same pair of chromosomes, called homologues, begin to pair
together. The process of pairing is called synapsis and a pair of synapsed homologous
chromosomes is called a bivalent or a tetrad. The end of synapsis marks the end of zygotene
and the beginning of the next stage called pachytene. This stage is characterized by the
occurrence of an important phenomenon called crossing over, in which parts of homologous
chromosomes are exchanged. Crossing over is responsible for generating genetic diversity
among the gametes. The beginning of diplotene is characterized by the tendency of the
homologous chromosomes to pull away from each other. As the homologous chromosomes
move apart they are seen to remain attached to each other at specific points by X-shaped
structures known as chiasmata. During the final stage called diakinesis, the meiotic spindle is
assembled and the chromosomes condense further to their maximally compacted state.
Diakinesis ends with the disappearance of the nucleolus, breakdown of the nuclear envelope
and the movement of the tetrads to the metaphase plate.
4.2.1.2.3 Metaphase I
At metaphase I, the bivalents attached to the spindle microtubules by their kinetochores, line up
on the metaphase plate. Each pair of homologous chromosomes is oriented in such a way that
the sister chromatids of each chromosome face the same pole. The spindle fibers from a given
pole are connected to both chromatids of a single chromosome.
4.2.1.2.4 Anaphase I
At the start of anaphase I, the kinetochores of the two chromosomes making up each bivalent
begin to move toward opposite poles of the cell, pulling the homologous chromosomes of each
bivalent apart. The sister chromatids of each chromosome are apparently released from
whatever forces were holding them in close apposition, allowing the recombinant chromatids to
go to a single pole.
4.2.1.2.5 Telophase I and Cytokinesis
The movement of homologous chromosomes to opposite poles is completed during telophase I.
Also, two nuclear envelopes form, each containing only one (duplicated) chromosome of each
homologous pair. The cytoplasm then splits to produce two daughter cells.
Worksheet No 26
Q1. Meiosis involves how many successive nuclear divisions
Q2. At the end of the meiosis, how many haploid cells are produced from a single diploid
cell
Q3. Why this process (meiosis) is essential ?
Q4. The meiosis is divided into into basically two phases as Meiosis I and Meiosis II. The
prophase I of meiosis I is very long and complex, and is usually divided into how many
sequential stages.
Q5. What are homologues or homologous chromosome.
Q6. What is the name of process of pairing of homologous chromosome.
Q7. What do you understand by term bivalent or tetrad.
Q8. Which stage is characterized by the occurrence of an important phenomenon called
crossing over
Q9. What is the structures known as chiasmata.
Q10 How the pair of homologous chromosomes is oriented in metaphase I of meiosis I
Q11. The movement of homologous chromosomes to opposite poles is completed during
which stage.
Q12. Explain the process of Prophase I of meiosis I with help of well labelled diagram.
May 8,2020
4.2.1.2.6 Meiosis II
The second meiotic division usually follows almost immediately and it is similar to mitosis. The
interphase between two divisions is either very short or nonexistent, depending on the species.
Prophase II is very brief. If detectable at all, it is much like mitotic prophase. Metaphase II also
resembles the equivalent stage in mitosis, except that only half as many chromosomes are
present on the metaphase plate. Anaphase II follows, effecting the separation of sister
chromatids. The new daughter chromosomes move to opposite poles. This movement is
completed in telophase II and a nuclear envelope forms around each of the haploid nuclei.
Worksheet No 27
Q1. The second meiotic division usually follows almost immediately after Meiosis I and it is
similar to which cell divison.
Q2. Is there any interphase between two divisions of Meiosis?
Q3. Describe the different stages of Meiosis II with help of well labelled diagram?
Q4. Explain the significance of Meiosis?
May 9,2020
4.2.2 Cell Cycle
The cells in the body continuously undergo alternation between division and non-division. The
events that occur from the completion of one division until the beginning of the next division
constitute cell cycle. The cell cycle is divided into two basic parts - mitosis and interphase.
Mitosis (M phase) about which you have learned in the previous section however forms only a
small part of the cell cycle. For example, a eukaryotic cell usually takes 18-24 hours to complete
cell cycle and mitosis occupies only about one hour of this time. The remaining part of the cell
cycle is spent in interphase. A typical cell cycle is shown in Fig. 3. Interphase is characterized by
absence of visible chromosomes. These have uncoiled to form chromatin fibers so that the
interphase nucleus looks homogeneous. At the molecular level however interphase is
characterized by a lot of activity in the form of DNA replication and protein synthesis so that the
cell may be prepared for the next division.
Interphase consists of three phases: G1 phase, S phase and G2 phase. During G1 (gap1)
phase the cell is metabolically active and grows continuously but its DNA does not replicate
during this phase. During S phase replication of DNA occurs. During G2 (gap2) phase, cell
growth continues so that cell may be prepared for mitosis. Although names G1 and G2 imply
these phases to be mere gaps between mitosis and S phase, many essential processes occur
during these phases. The durations of S and G2 phases are fairly consistent among different cell
types. Much variation is seen in the duration of the G1 phase.
The G1 phase is of particular interest. The reason is that late in G1 phase, all cells follow one of
the two paths. They may either become committed to start DNA synthesis and complete the cell
cycle or withdraw from the cell cycle to enter a resting phase (G0 phase). Cells that enter G 0
phase remain viable and metabolically active, but are non-dividing. Cells may remain in G0
phase from days to years, but may be stimulated to enter G phase and re-enter the cell cycle.
Some cells enter G0 phase and remain in this phase for rest of their lives, never entering the cell
cycle again. Still others do not enter the G0 phase at all or enter this phase for a very short
period
for example, cancer cells. Consequently they just keep dividing endlessly.
Once G1 , S and G2 phases are completed, mitosis (M) is initiated.
Fig. 3. Cell cycle
Worksheet No 28
Q1 The cells in the body continuously undergo alternation between division and non-division.
The events that occur from the completion of one division until the beginning of the next division
constitute what ?
Q2. Cell cycle is basically divided into two basic parts as
Q3. How much time eukaryotic cell usually takes to complete cell cycle
Q4. How much time normally mitosis occupies out of cell cycle.
Q5. At the molecular level, interphase is characterized by what activity?
Q6. What are different phases of Interphase stages.
Q7. Describe the events takes place in following stages:
a) During G1 (gap1)
b) During G2 (gap2)
c) During S phase
Q8. The durations of S and G2 phases are fairly consistent among different cell types or not?
Q9. Much variation is seen in the duration of which phase of Interphase?
Q10. The cells that are late in G1 phase, all cells follow one of the two paths. What are its
different pathways.
May 10,2020
HOLIDAY
May 11,2020
4.2.2.1 Cell cycle regulation
It is interesting to note that cell cycle is fundamentally the same in all eukaryotic organisms. How
does the cell ensure that the events that occur during various phases (G1, S, G2 and M) of cell
cycle occur in the correct order, and are coordinated? For example, it is important that cell does
not begin mitosis until replication of DNA has been completed. This co-ordination between
various phases of cell cycle is dependent on a series of cell cycle checkpoints. The first
checkpoint is G1 /S checkpoint. Here the cell size is monitored. If the size of the cell is proper
and DNA has not been damaged, the cell enters the S phase. The second checkpoint is G2 /M
checkpoint. If the DNA replication is not complete or any damage to DNA has not been repaired,
cell cycle is arrested at this point. The final checkpoint occurs during mitosis and is called
metaphase checkpoint or M phase checkpoint. Here, if the spindle fibers are not formed properly
or if their attachment to kinetochores is inadequate, mitosis is arrested. This is how a cell
ensures that only normal healthy cells are produced. Failure of any of these 'checkpoint controls'
results in increased genetic damage.
What are the molecular events taking place at cell cycle checkpoints? It is, now known, that
these are regulated by a number of heterodimeric protein kinases. The regulatory subunit of
these kinases is called cyclin and the catalytic subunit is called cyclin-dependent kinase
(Cdk). Each Cdk catalytic subunit can associate with different cyclins and the associated cyclin
determines which proteins are phosphorylated by the Cdk-cyclin complex. For example,
progression through G1and S is regulated mainly by Cdk2, Cdk4 and Cdk6 in association with 1
cyclins D and E. Cdk1 and A-type cyclins regulate passage from S to G2 . The passage through 2
G2 to M is regulated by Cdk1 in association with B-type cyclins.
The DNA damage checkpoints which are also operative during G1 , S and G2 phases will arrest
the cell cycle progression if DNA is damaged. This allows the repair of DNA before cell cycle is
resumed. This is regulated by checkpoint kinases CHK1 and CHK2.
Worksheet No 29
Q1. How cell cycle is regulated and what are its various check points?
Q2. What are the various checkpoints and what is checked ?
Q3. What is being regulated at various check points
a) The first checkpoint or G1 /S checkpoint.
b) The second checkpoint is G2 /M checkpoint'
c) The final checkpoint/metaphase checkpoint/M phase checkpoint.
Q4 How a cell ensures that only normal healthy cells are produced.
May 12,2020
4.2.3 Cell Communication
All cells communicate with each other, and with their environment. For example, simple
organisms like bacteria can sense the presence of nutrient molecules like glucose and amino
acids in their environment and move towards them. The eukaryotic cells can sense presence of
molecules secreted by other cells and respond to them, allowing cell-cell communication. This is
accomplished by a variety of signalling- molecules, which are secreted by one cell and bind to
receptors expressed by other cells.
The signaling molecules to which plant and animal cells respond range from as simple as ions
and gases to complex proteins. For example, nitric oxide is a major signaling molecule in
nervous, immune and circulatory systems. Among the complex molecules hormones, growth
factors and cytokines represent major signaling molecules. A class of lipids called eicosanoids
includes signaling molecules like prostaglandins and leukotrienes. The distance at which these
signaling molecules act also varies. Some act locally where as other can carry signals over long
distances.
Most signalling molecules bind to receptors expressed on the surface of target cells. Others can
enter the cell and bind to intracellular receptors. There are a variety of receptors to which
signalling molecules bind. A large family of cell surface receptors act via guanine nucleotide
binding proteins (G proteins). These are called G protein-coupled receptors. Another group of
receptors act by phosphorylating their substrate proteins at tyrosine residues.
Once a signaling molecule binds receptor on a cell, it initiates a series of intracellular reactions
towards interior of the cell and signal is transmitted from cell membrane to nucleus. This process
is called intracellular signal transduction. The signal may be transmitted directly or via a
cascade pathway involving many proteins. These pathways between the cell membrane and the
cell nucleus are called signal transduction pathways. There is an amazing degree of
networking among these pathways. A large variety of molecules are involved in these pathways
and include molecules like cyclic AMP (cAMP), Ca+2 and calcium-binding protein calmodulin,
MAP (mitogen activated protein) kinases, NF-?B (nuclear factor- kappa B) transcription factor
etc. All this results in cellular response that may include changes in gene expression,
differentiation, replication, alteration of enzyme activity, changes in ion permeability or even
death of the cell.
It is interesting to know that a single cell may have several types of receptors each binding only
to a specific signaling molecule. Thus, a cell may simultaneously receive information in the form
of signals from all these receptors. Once the signals have been relayed into the cells, they are
selectively routed along the various signal transduction pathways.
Worksheet No 30
Q1 What do you understand by cell-cell communication.
Q2. What are signalling- molecules ?
Q3 Give some examples of signaling molecules
Q4. Nitric oxide is a major signaling molecule in nervous, immune and circulatory
systems. Among the complex molecules hormones, growth factors and cytokines
represent major signaling molecules. A class of lipids called eicosanoids includes
signaling molecules, give some examples of it.
Q5. What are intracellular signal transduction/ signal transduction pathways
Q6 A large variety of molecules are involved in signal transduction pathways, give some
examples of them
May 13,2020
4.2.4 Movement
Movement is an important feature of the living organisms. It is a different matter though, that
movement in the form of locomotion, is most visible in animals i.e. animals can move from one
place to another. In animals, movement is possible due to the contraction of muscles. In plants,
movement is dependent on wind and water currents. Single-celled prokaryotes and eukaryotes
move by hair like appendages called cilia and flagella, or by amoeboid movements.
4.2.4.1 Amoeboid movement
Amoeboid movement is characteristic of some protozoa, slime molds (fungi) and the white blood
cells. In this type of movement, the cytoplasm flows into a newly formed arm-like extension
(pseudopodium) of the cell. This gradually extends and enlarges so that the entire cell occupies
the space where previously only a small pseudopodium (pl. pseudopodia) had begun to form.
As the cell moves, new pseudopodia are formed in the direction of movement while the earlier
ones are withdrawn. Amoeboid movement has obvious similarity with cytoplasmic streaming
(cyclosis), a commonly observed phenomenon in all plant and animal cells. Cytoplasmic
streaming plays an important role in intracellular transport.
4.2.4.2 Movement by cilia and flagella
Cilia and flagella are thread like appendages and have similar internal structure. The difference
between them relates to their different beating patterns. A flagellum beats with a symmetrical
undulation that is propagated as a wave along its length. A cilium, in contrast, beats
symmetrically with a fast stroke in one direction followed by slower recovery motion. A flagellated
cell usually carries only one or few flagella while a ciliated cell may have several thousand cilia
distributed on the surface. The flagella of the bacteria are quite different. These are thinner
(0.02 ìm in diameter against 0.25 m for true flagella and cilia), short and relatively rigid and are
rotated by force at the base where they are attached to the cell. Cilia and flagella are found in
many protozoa. The sperms of a vast number of animals swim by means of flagella. Cilia also
perform specialized functions. In mammals, ciliated epithelium aids in the transport of materials
on the internal surfaces for example, moving mucus on the respiratory tract.
Worksheet No 31
Q1. Give some examples of Amoeboid movement
Q2. Explain the process of amoeboid movement.
Q3. Give example a kind of movement in plant which has obvious similarity with Amoeboid
movement
Q4. Cilia and flagella are thread like appendages and have similar internal structure. The main
difference is basically due to ?
Q5. Explain the difference between the beating pattern of cilia and flagellum ?
Q6 Give some examples of Cilia where it perform specialized functions in mammals.
May 14 ,2020
4.2.4.3 Muscle and movement
Muscle is a tissue, which is unique to animals and plays a leading role in the ability of the
animals to move. Muscle tissue is specialized for one crucial function: contraction.
Each muscle consists of a number of muscle fibers. Each muscle fiber further consists of many
myofibrils. Myofibrils consist of structures called sarcomeres that do the work of contraction.
Under a microscope, sarcomeres are seen as bands. Each sarcomere is bounded on two sides
by dark lines called Z discs. Each sarcomere consists of a very specific arrangement of two
proteins - actin and myosin. Z discs are the anchor points of actin filaments. From the Z discs,
the actin filaments extend towards the center of the sarcomere. Between the actin filaments lie
the myosin filaments, each of which consist of many myosin molecules (Fig. 4 a, b).
In the presence of energy molecules (ATP), actin filaments pull the two Z discs inwards. In this
process, the myosin filaments slide over the actin filaments and this causes contraction of
muscle. To exert this force, muscles are anchored to mechanical structures i.e. skeletal system.
Fig. 4. Contraction of muscle during which myosin molecule slide over the actin filaments
4.2.5 Nutrition
All living things must eat to live. Thus, absorption of the nutrients from the environment is a basic
feature of all living beings. Nutrients are needed to provide energy and to maintain various body
processes such as metabolic machinery, growth and reproduction. Animals, plants and
microbes obtain their nutrition in different ways. Before we discuss these, we would like to know
the basic elements of the nutrition.
4.2.5.1 Elements of nutrition
Carbon, hydrogen and oxygen provide the basis for life. These three elements form the
framework of organic molecules such as carbohydrate, proteins, fats and nucleic acids. Some
additional elements such as nitrogen, phosphorous, and sulfur bond covalently to carbon
hydrogen- oxygen backbones in amino acids, nucleotides and lipids, and play equally critical
role. Many other elements such as sodium, calcium, magnesium, chloride etc. play equally
essential roles. They are not covalently bonded to organic molecules, but exist either as ions or
in association with organic molecules. Elements like manganese, copper, zinc, cobalt,
selenium, and iodine are required in very small amounts and are called micronutrients or trace
elements. Some of these trace elements are part of vitamins and play important function in
animal nutrition.
Worksheet No 32
Q1 Each muscle consists of a number of muscle fibers, and each muscle fiber further consists of
many................................
Q2. Myofibrils consist of structures called ............ that do the work of contraction.
Q3. What are the basic role of nutrients to organisms?
Q4. What are various elements of nutrition.
Q5 Give some examples of micronutrients or trace elements.
Q6. Explain the process of muscle contraction in animals
May 15 ,2020
4.2.5.2 Plant nutrition
Plants obtain a major part of their nutrition from the environment. Using sunlight as the source of
energy and CO from the atmosphere, plants synthesize sugar molecules by the process of
photosynthesis. Sugar molecules in the plant can be further converted to proteins and lipids.
Water and various minerals are taken through their root system.
Plants carry out photosynthesis in their leaves. Leaves are positioned on branches so that they
are exposed as fully to light as possible. Most photosynthesis takes place in the palisade
parenchyma (see chapter 1) that lies mostly in the sunlight, upper half of the leaf. Spongy
parenchyma specialized for CO absorption mostly lies in the lower half of the leaf.
Plants take up inorganic nutrients from the soil through roots along with water. Root hairs are
thin-walled extensions of the epidermal cells in roots. They provide increased surface area and
thus more efficient absorption of water and minerals. Some plants such as those belonging to
legume family have symbiotic association with bacteria. The bacteria form the root nodules and
live in them. In the nodules, bacteria convert atmospheric nitrogen (which plants cannot use) to
organic form that can be used by the plants.
4.2.5.3 Animal nutrition
Contrary to plants, animals cannot photosynthesize and thus cannot synthesize organic
molecules from inorganic raw materials. They must consume the organic molecules
synthesized by plants. The organic molecules of plants are digested or broken down to simpler
nutrients in the digestive tracts of the animals. These are absorbed through the intestine into the
tissues of the animal. These are then used to synthesize the organic compounds of animals,
using their own machinery. Therefore, the organic molecules of the animals are actually derived
from plants and indirectly from sunlight.
Some bacteria, which live in the gut of the animals, also help in animal nutrition. Bacteria in the
human gut synthesize vitamin K and vitamin B that are absorbed by the human body and
utilized for various functions. Bacteria found in the rumen of cattle break down the cellulose of
the fodder into smaller sugar molecules, which are absorbed by the cattle.
Vitamins are nutrients unique to animals. Animals need vitamins in only small amounts, but they
are either unable to synthesize them or cannot synthesize enough to meet their needs. Thus,
they must get vitamins in their food. The nutritional needs of vitamins may vary greatly among
animals. Humans require two types of vitamins: water soluble (B , B , B , B , C, folic acid, niacin 1
etc.) and fat soluble (A, D and E)
Deficiency of any of the nutrients discussed above in relation to animal nutrition, can lead to
disease or deformities. Protein deficiency is generally seen in children and manifests in the form
of stunted growth. Deficiency of iron or folic acid can lead to anemia and that of vitamin C to
scurvy (bleeding gums). Deficiency of vitamin D leads to bone deformities. Vitamin A deficiency
causes weak eyesight. Deficiencies of vitamin B and B can cause nervous tissue problems.
Worksheet No 33
Q1. Basically plants obtain a major part of their nutrition from the environment through a process
called ........................
Q2. Describe the process of photosynthesis?
Q3. Did there is a difference in process of photosynthesis in terms of types of Parenchyma
Q4. Describe the role of
a) Palisade parenchyma
b) Spongy Parenchyma
Q5. How does symbiotic association of bacteria help the plants.
Q6. Did animals are able to synthesize organic molecules from inorganic raw materials?
Q7. Bacteria in the human gut synthesize vitamin....... and vitamin....... that are absorbed by the
human body and utilized for various functions.
Q8 Bacteria found in the .................... of cattle break down the cellulose of the fodder into smaller
sugar molecules, which are absorbed by the cattle
Q9 What are Vitamins and what is their basic role
Q10 Name some water soluble vitamins
Q11. Name some fat soluble vitamins
Q12. What diseases will be caused by following
a) Protein deficiency seen in children
b) Deficiency of iron or folic acid
c) Deficiency of vitamin C
d) Deficiency of vitamin D
e) Vitamin A deficiency
f) Deficiencies of vitamin B
May 16 ,2020
4.2.5.4 Nutrition in microbes
Most microbes such as bacteria and fungi obtain their nutrition from plants and animals. Bacteria
and fungi grow on dead plants and animals. They produce a number of enzymes, which can
break down the complex organic molecules of plants and animals into simpler nutrients.
Bacteria and fungi then use these nutrients to synthesize their own organic molecules. These
organisms are also called saprophytes.
4.2.6 Gaseous Exchange
Almost all living beings exchange carbon dioxide and oxygen with their environment. The
photosynthesizing plants take up carbon dioxide from the atmosphere. The animals produce
CO2 during respiration. Both plants and animals use oxygen for respiration. It is interesting to
note that oxygen and carbon dioxide move in and out of the living cells by the process of
diffusion. Two important factors determine the rate of diffusion - the concentration gradient of the
gas, and the nature of the surface where gaseous exchange takes place.
4.2.6.1 Gas exchange surfaces
The single-celled organisms like bacteria and protozoa exchange gases directly across their cell
membranes. However, higher organisms like plants and animals use other means for the
exchange of gases.
Body surface: Some multicellular organisms such as earthworm or algae exchange gasses
across the outer layer of their cells. Amphibians use their skin as a respiratory surface. Such
surfaces are usually moist as this allows easy exchange of oxygen and carbon dioxide.
Gills: Aquatic animals such as fishes have gills, which provide large areas for gas exchange.
Typically, gills are convoluted outgrowths containing blood vessels and are covered by a thin
epithelial layer. Gills are very efficient in taking up oxygen from water.
Alveoli: The terrestrial animals have very efficient internal organs for gas exchange. These
are called lungs. The lungs are elastic sacs that allow the animals to pump air in and out of the
body. The trachea of an animal's respiratory system bifurcates into two bronchi, which in
turn divide into many bronchioles. The bronchioles end in tiny thin walled (single-celled)
sacs called alveoli. Although, individually, alveoli are tiny, the combined surface of all alveoli
put together in the lungs is enormous. They are richly supplied with blood vessels. As the air
is taken into the lungs (inspiration), at the alveolar surface oxygen is dissolved into the blood
while CO comes out. During expiration, the CO is exhaled out.
4.2.6.2 Gas exchange in plants
In plants, air enters into the spongy parenchyma of leaves through stomata. Here, CO diffuses 2
directly from the air spaces into the photosynthesizing cells.
Worksheet No 34
Q1. What kind of nutrition is present in and Fungi and how they get their nutrition.
Q2. What are Saprophytes?
Q3. What are the two important factors which determine the rate of diffusion
Q4. How respiration takes place in following cases and explain by giving examples
a) Body surface
b) Gills
c) Alveoli
Q5. In plants, how gaseous exchange takes place.