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.