1

10th SSC BIOLOGY NOTES

Mis. R . Da s
201 9

Mis. R. Das
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TABLE OF CONTENTS

1. Heredity and Evolution

2. Life Process in living organisms Part-1

3. Life Process in living organisms Part-2

4. Environmental management

5. Towards green energy

6. Animal classification

7. Introduction to microbiology

8. Cell biology and biotechnology

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1. Heredity and Evolution

❖ What is heredity?
➢ Heredity is the transfer of biological characters from one generation to
another via genes.

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❖ Translation and translocation:

➢ Each m-RNA is made up of thousands of triplet codons.
➢ As per the message on m-RNA, amino acids are supplied by the t-
RNA
➢ t-RNA has anti-codon and binds with m-RNA inside the r-RNA.
➢ r-RNA stands for ribosomal RNA.
➢ This is called translation.
➢ Due to process of translation, the r-RNA moves from one end of m-
RNA to another end of m-RNA.
➢ This is called translocation.

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❖ Mutation:
➢ Mutation can cause genetic disorder like sickle cell anaemia.

❖ Evolution :
1) Formation of new species due to changes in specific characters of
several generations of living organisms as a response to natural
selection is called as evolution.
❖ Theory of evolution:

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1) According to this theory, first living material (protoplasm) has been

formed in ocean.
2) And then unicellular organism was formed.
3) Gradually changes occurred and multi cellular organisms were
formed.
4) Duration of these changes is at most 300 crore years.

❖ Evidences of evolution:

1) Morphological evidences:
➢ Various similarities in animals like structure of mouth, position of
eyes, structure of nostrils and ear pinnae, thickly distributed hairs
on body are seen in animals.
➢ In plants we can see similarities in leaf shape, leaf venation, leaf
petiole, etc.
➢ Hence, it proves that their origin must be same and must have
common ancestors.

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2) Anatomical evidences:
1) There is no superficial similarities between human hand, cat’s
foreleg, flipper of whale and patagium of bat.
2) Similarly, use of each of those structures is different in respective
animals.
3) However, there is similarities in structure of bones and bony joints
in organs of each of those animals.
4) Hence, they can have common ancestors.

3) Vestigial organs:
1) Degenerated or underdeveloped useless organs of organism are
called as vestigial organs.
2) Existing organs undergo gradual changes due to changing
environment.

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3) It takes thousands of years for a structure to disappear.

4) And during these years it is called as vestigial organs.
5) It is useless in humans, and is fully useful and functional in
ruminants.

6) Muscles of ear pinna are useless in humans, but is useful in

monkeys, etc.

7) Waste in humans but, useful for other animals.

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8) Waste in humans but, useful in animals.

❖ Paleontological evidences:
1) Large number of organisms get buried due to disasters like flood,
earthquake, volcano, etc.
2) Remnants and impressions of such organisms remain preserved
underground.
3) These are called as fossils.
4) These fossils are very important for study of evolution.
5) Carbon consumption of animals and plant stops after death and
then only the decaying process of c-14 (6protons, 8neutrons) i.e
radioactive, occurs continuously.
6) The ratio between c-14 and c-12 (6protons, 6neutrons) changes
continuously as c-12 is non-radioactive.
7) The time passed since the death of plant and animal can be
calculated by measuring the radioactivity of C-14 and ratio of C-14
and C-12 present in their body.
8) This is called carbon- dating method.
9) It is used in palaeontology and anthropology for determining the
age of fossils.

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10) It is proved that vertebrates came from invertebrates, using this

method.

❖ Connecting links:
1) Some plants and animals show some morphological characters by
which they can be related to two different groups, hence they are
called as connecting links.
2) In peripatus, characters like segmented body, thin cuticle and
parapodia-like (polyceate) organs are present.

3) Similarly, these animals show tracheal respiration (direct exchange

of gases) and open circulatory system similar to arthropods.
4) This indicates that peripatus is connecting link between annelida
and Arthropoda.

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5) Similarly, duck billed platypus lays eggs like reptiles but, shows
relationship with mammals too due to presence of mammary glands
and hairs.

6) Lung fish performs respiration with lungs irrespective of being fish.

7) These examples indicates that mammals are evolved from reptiles

and amphibians from fishes.
❖ Embryological evidences:
1) All embryos show extreme similarities during initial stages and
those similarities decrease gradually.
2) Similarities in initial stages indicate the common origin of all these
animals.

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❖ Darwin’s theory of natural selection:

1) Chales Darwin published the theory of natural selection which says,
the survival of fittest.
2) He published a book titled, ‘origin of species’.
3) It says that, all organisms reproduce prolifically (large numbers of
quantity).
4) All the organisms compete with each other in a life- threatening
manner.
5) In this competition, only those organisms sustain which shows the
modification essential for winning the competition.
6) Nature selects only those organisms which are fit to live and the rest
perish.
7) This theory was accepted world wide but, there are some points
which should be noted…
a) Natural selection is not the only factor responsible for evolution.
b) Darwin did not explained anything about useful and useless
modification.
c) There is no explanation about slow changes and abrupt
(unexpected) changes.
❖ Lamarckism :
1) Concept of ‘Use or disuse of organs’, was given by jean-baptiste
Lamarck.
2) This concept says that if an organism is using their particular organ
or body part, its activity results as evolution of that organ or part.

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3) Just as neck of giraffe, they constantly use it to reach the leaves of

the tall tree to eat, this results in evolution of there neck.
4) Also, if there is laziness i.e no use of organ or body part in an
organism it results in evolution of that part.
5) For example, wings of birds like ostrich and emu have become weak
due to no use.
6) Living organism can transfer the characters which it has acquired to
the next generation, this is called ancestry of acquired characters.

❖ Speciation:
1) Formation of new species of plant and animal is the effect of
evolution.
2) Species is the group of organism that can produce fertile individuals
through natural reproduction.
3) Their food, habitat, reproductive ability is different depending on
the geographic conditions.
4) However, genetic variation is responsible for formation of new
species from earlier one.
❖ Human evolution:

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1) The bio-diversity that is known today has been said to be formed

from very simple unicellular organism due to evolution.
2) Last dinosaurs disappeared approximately seven years ago.
3) At that time monkey like animal was said to be evolved from some
ancestors, the tail of these animal of Africa was disappeared about 4
crore years ago.
4) Due to this evolution ‘ape’ can into existence.
5) These ape’s reached the south and north-east Asia and evolved into
gibbon and orangutan.
6) Remaining ape’s stayed at Africa and evolved into gorilla and
chimpanzee about 2.5 crore years ago.

7) The first human animal with erect posture have evolved about 2
crore Years ago.
8) The ape of south Africa was evolved about 40 lakh years ago.
9) The morphology of these animal started to appear like the member
of genus Homo, about 20 lakh years ago; thus human developed.
10) Then the development of brain took place for the period of about 1
lakh years and then discovery of fire took place.

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11) Then a wise-man was considered about 50 thousand year old man,
and named Homo sapiens.
12) Neanderthal man can be considered as the first example of wise-
man.
13) The cro-magnon man evolved about 50 thousand years ago.
14) About 10 thousand years ago, wise-man started to practice the
agriculture.
15) They started to rear the cattle-herds and established the cities.
16) Cultural development took place.
17) Art of writing was invented about 5000 years ago.
18) Modern science emerged about 400 years ago.
19) Industrial society was established about 200 years ago.

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2. Life Process in living organisms

Part-1

❖ Life Processes:
1) Various organ-system are continuously performing their functions
in human body.
2) Systems like digestive, respiratory, circulatory, excretory and control
system(nervous system).
3) For all these processes to happen they need continuous source of
energy.
4) Carbohydrates, fats and lipids are the main sources of energy and it
is harvested by mitochondria present in each cell.
5) Oxygen is also very important in process of energy formation.
6) Food stuffs and oxygen are transported up to the cell via circulatory
system.
7) We obtain the carbohydrates from milk, fruits, jaggary, cane sugar,
Vegetables, potatoes, sweet potatoes, sweet meats eg; jalebi and
cereals (grain food) like wheat, maize, ragi, jowar, millet, rice, etc.
8) We get 4 kilo cal energy per gram of carbohydrates.
❖ Energy production:
1) In living organisms, respiration occurs at two levels as body and
cellular level.
2) Oxygen and carbon dioxide are exchanged between body and
surrounding in case of body level.

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3) In case of respiration at cellular level, foodstuffs are oxidized either

with or without help of oxygen.
4) Energy is obtained in the form of ATP.
5) For this purpose glucose, a type of carbohydrate is oxidized step by
step in the cell.
6) This is called as cellular respiration.
7) These are of two methods; aerobic respiration (oxygen is involved)
and anaerobic respiration (oxygen is not involved).
8) In aerobic respiration, glucose is oxidized in three steps:
9) Glycolysis.
10) Tricarboxylic acid cycle (kreb cycle).
11) Electron transfer chain reaction (ETS).

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12) Thus, a molecule of glucose is completely oxidized in aerobic

respiration and molecules of CO₂ and H₂O are produced along with
energy.
13) NADH₂= nicotinamide adenine dinucleotide
14) FADH₂= flavin adenine dinucleotide
15) Both of these enzymes are formed in the cells and used in cellular
respiration.

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16) ATP : adenosine triphosphate is energy-rich molecule and energy is

stored in the bonds by which phosphate groups are attached to each
other. These molecules are stored in the cells as per need.
❖ Adenosine ribonucleoside:
1) It contains a nitrogenous compound-adenine, pentose sugar- ribose
and three phosphate groups.
2) As per the need, energy is derived by breaking the phosphate bond
of ATP; hence APT is called as ‘energy currency’ of the cell.
3) If there is insufficient amount of carbohydrates in body due to
exceptional conditions like fasting and hunger, then lipids and
proteins are used for energy production.
4) In case of lipids, they are converted into fatty acids and proteins into
amino acids.
5) Fatty acids and amino acids are converted into acetyl-CoA and
energy is obtained through complete oxidation of acetyl-CoA by the
process of kerb cycle in mitochondria.

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❖ Energy production through anaerobic respiration:

1) Some organisms cannot live in presence of oxygen, eg; many
bacteria
2) Glycolysis and fermentation are the two steps of anaerobic
respiration.
3) Glucose is incompletely oxidized and less amount of energy is
obtained in this type of respiration.
4) Pyruvic acid produced through glycolysis is converted into other
organic acids or alcohol with the help of some enzymes in this
process. This is called as fermentation.
5) Some higher plants, animals and aerobic micro-organisms also
perform anaerobic respiration if there is depletion in oxygen level in
the surrounding.
6) Eg, seeds perform anaerobic respiration if the soil is submerged
under Water during germination.
7) Similarly, our muscle cells also perform anaerobic respiration while
performing the exercise.
8) Due to this, less amount of energy is produced in our body and
lactic acid accumulates due to which we feel tired.

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❖ Energy from different food components:

1) Excess of carbohydrates are stored in liver and muscles in the form
of glycogen.
2) Proteins are the macro-molecules formed by bonding together many
amino acids.
3) Proteins of animal origin are called as ‘first class’ proteins.
4) We get 4 kilo cal of energy per gram of proteins.
5) Amino acids are obtained after digestion of protein.
6) Those amino acids are absorbed in the body and transported up to
each organ and cell via blood.

❖ Amino acids:
1) Excess of amino acids obtained from protein are not stored in body.
2) They are broken down and the ammonia formed is eliminated out of
the body.

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3) If necessary, excess of protein are converted into other useful

substances like glucose through the process of gluconeogenesis.
4) Plants produce the necessary amino acids from minerals named
denovo.
5) An enzyme RUBISCO present in the plant chloroplasts is most
abundant protein found in nature.
6) The substances formed by specific chemical bond between fatty
acids and alcohol are called as lipids.
7) Lipids consumed break down into fatty acids and alcohol.
8) The molecules called as phospho lipids which are essential for
producing plasma membrane are formed from fatty acids.
9) Fatty acids are used for producing hormones like progesterone,
estrogen, testosterone, aldosterone (produced by adrenal gland),
covering around the axons of nerve cells.
10) We get 9 kilo Cal of energy per gram of lipids.
11) Excess of lipids are stored in adipose connective tissue in the body.
❖ Vitamins :
1) Vitamins are a group of heterogeneous compounds of which, each is
essential for proper operation of various processes in body.
2) There are main six types of vitamins, eg; A,B,C,D,E and K.
3) Out of these, A,D,E and K are fat-soluble whereas B and C are
water-soluble.
4) We have seen that, FADH₂ and NADH₂ are produced in the
processes like glycolysis and krebs cycle.

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5) Vitamins like riboflavin (vitamin B₂) and nicotinamide (vitamin B₅)

are necessary for these process.
❖ Water level in body:
1) There is about 65-70% water in our body.
2) Each cell contains 70% water weight by weight.
3) Blood-plasma also contains 90% of water.
4) Functioning of cells and thereby whole body disturbs even if there is
a little loss of water from the body.
5) Along with these things, fiber's are also essential nutrient.
6) We humans, cannot digest fibres, but they help in the digestion of
other substances and egestion of undigested substances.
7) fibres are obtained from leafy vegetables, fruits like banana and
cereals.
❖ What are the symptoms of diseases like night blindness, rickets,
beri-beri, neuritis, pellagra, anaemia, scurvy?
1) Night blindness: inability to see in dark.
2) Rickets: bones becomes thinner.
3) Beri-beri: muscle weakness.
4) Neuritis: temporary vision loss and pain.
5) Scurvy: fatigue (drowsiness) and bleeding in gums.
6) Anaemia: intense fatigue caused by loss of haemoglobin.
7) Pellagra: inflammation of the skin, diarrhoea, dementia (mental
illness).
❖ Cell division: an essential life process.

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1) Due to cell division, new organism is formed from existing one, a

multicellular organism grows up, and emaciated body can be
restored.
2) There are two types of cell division as mitosis and meiosis.
3) Mitosis occurs in somatic cells and stem cells (immune cells) of the
body, whereas meiosis occurs in germ cells.
4) Every cell has nucleus which contains DNA.
5) Before any type of cell division, the cell doubles up its chromosome
number present in its nucleus; if chromosome number is 2n, it is
doubled up to 4n.
❖ Mitosis :
1) Somatic cells and stem cells divide by mitosis.
2) Mitosis is completed in two main steps: karyokinesis (nuclear
division) and cytokinesis (cytoplasmic division).
3) Karyokinesis has 4 steps...
i) Prophase
ii) Metaphase
iii) Anaphase
iv) Telophase
i) Prophase :
1) In prophase, condensation of basically thin thread like chromosomes
start.
2) Due to this they become short and thick and their pair of sister
chromatids start to appear.

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3) Centrioles duplicate and each centriole moves to opposite poles of

the cells.
4) Nuclear membrane and nucleolus start to disappear.

ii) Metaphase :
1) Nuclear membrane completely disappears in metaphase.
2) All chromosomes are arranged parallel to equatorial plane.
3) Special type of protein fibres (spindle fibres) are formed between
centromere of each chromosomes and both centrioles.

iii) Anaphase :
1) In anaphase, centromeres split and their sister chromatids of each
chromosome separate and they are pulled apart in opposite
direction with the help of spindle fibre.
2) Separated sister chromatids are called daughter chromosomes.

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3) In this way, each set of chromosomes reach at two opposite poles of

the cell.

iv) Telophase :
1) The chromosomes which have reached at opposite poles now star to
decondense due to which they again become thread- like structure.
2) Nuclear membrane again starts to form around them.
3) Now two daughter nuclei are formed in the cell.
4) Nucleolus also appears and spindle fibre disappears.

❖ Cytokinesis:
1) The cytoplasm divides by cytokinesis and two new cells are formed
which are called as daughter cells.
2) In this process, a notch is formed at the equatorial plane of the cells
which deepens gradually and thereby two new cells are formed.

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3) In case of plant cells, instead of notch, a cell plate is formed exactly

along midline of the cell and thus cytokinesis is completed.

❖ Activity:
Apparatus: conical flask, glass slides, cover slips, forceps, compound
microscope, watch glass, etc.
Materials: a medium sized onion, iodine solution, etc.
Procedure: 1) take a medium sized onion.
2) keep it in a conical flask filled with water in such a way that the root of
onion will be in contact of water.
3) observe the roots of onion after 4-5 days.
4) cut the tips of some of the roots and put them in a watch glass.
5) pour some drops of iodine in watch glass.
6) take one of the root tip on glass slide press it with the help of forceps.

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7) add 1-2 drops of water and place a cover slip on it.

8) observe the prepared glass slide under the compound microscope.
9) which phase of cell division do you observe?

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3. Life Process in living organisms

Part-2

❖ Introduction:
1) All those life processes i.e nutrition, respiration, excretion, sensation
and response (control and co-ordination), etc are essential to each
living organisms to remain alive.
2) Besides, these life processes, one more life process occurs in living
organisms; it is reproduction.
3) However, reproduction does not help the organism to remain alive
but it helps to maintain the continuity of the species of that
organisms.
4) Formation of new organisms of same species by earlie5r existing
organisms is called as reproduction.
5) It is responsible for evolution of each species.
6) In living organisms reproduction occurs mainly by two methods;
sexual and asexual reproduction.
❖ Asexual reproduction:
1) Process of formation of new organism by an organism of same
species without involvement of gametes is called as asexual
reproduction.
2) As this reproduction does not involve union of two different
gametes, the new organism has exact genetic similarity with the
reproducing organism.

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3) This is uniparental reproduction and it occurs by mitotic cell

division.
4) Absence of genetic recombination is a drawback whereas fast
process is advance of this reproductive method.
❖ Asexual reproduction in unicellular organisms:
A) Binary fission:
1) Prokaryotes (bacteria), protists (amoeba, paramecium, euglena, etc.)
and eukaryotic cell organelle like mitochondria and chloroplasts
performs asexual reproduction by binary fission.
2) In this process, the parent cell divides to form two similar daughter
cells.
3) Binary fission occurs either by mitosis or amitosis.
4) Axis of fission/division is different in different protists. Eg. Amoeba
divides in any plane due to lack of specific shape; hence it is called
simple binary fission.
5) Paramecium divides by transverse binary fission, whereas Euglena
by longitudinal binary fission.
6) Binary fission is usually performed by living organisms during
favourable conditions i.e availability of abundant food material.

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B) Multiple fission:
1) Asexual reproduction by multiple fission is performed by amoeba
and other similar protists.
2) Amoeba stops the formation of pseudopodia and thereby
movements whenever there is lack of food or any other type of
adverse condition.
3) It becomes rounded and forms protective covering around plasma
membrane.
4) Such encysted amoeba or any other protist is called as cyst.
5) Many nuclei are formed by repeated nuclear divisions in the cyst.
6) It is followed by cytoplasmic division and many amoeba are formed.
7) Cyst breaks open on arrival of favourable conditions and many
amoeba are released.

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C) Budding:
1) Asexual reproduction occurs by budding in yeast (a unicellular
fungus).
2) Yeast cell produce two daughter nuclei by mitotic division, so as to
reproduce by budding. This yeast is called as parent cell.
3) A small bulge appears on the surface of parent cell. This bulge is
actually a bud.
4) One of the two daughter nuclei enters the bud.
5) After sufficient growth, bud separates from the parent cell and
forms a new yeast.

❖ Asexual reproduction in multicellular organisms:

A) Fragmentation:
1) This type of reproduction occurs in multicellular organisms.
2) Here, the body of parent organisms breaks up into many fragments
and each fragments starts to live as an independent new organism.
3) This happens in algae like spirogyra, and sponges like sycon.
4) Whenever there is plenty of water and nutrients are available to
spirogyra, its filaments grow up very fast and break up into small
fragments.
5) Each fragment starts to live independently as a new spirogyra fibre.

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6) If the body of sycon breaks up accidentally into many fragments,

each fragments develops into new sycon.

B) Regeneration:
1) You may know that wall lizard breaks up and discard some part of
its tail in emergency. Discarded part is regenerated after a period.
2) This is an example of limited regeneration.
3) Similarly, an animal- planaria breaks up its body into two parts and
thereafter each part regenerates the remaining parts of body.

C) Budding:
1) In case of hydra, under favourable conditions, at specific part of its
body, an outgrowth is formed by repeated divisions of regenerative
cells of body wall. This outgrowth is called as bud.
2) This bud grows and forms a small hydra. Dermal layers and
digestive cavity of the budding hydra are in continuity with those of
parent hydra. Parent hydra supplies nutrition to budding hydra.

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3) As the budding hydra grows stronger it detaches from the parent

hydra and live independently.

D) Vegetative propagation:
1) Reproduction in plants with the help of vegetative parts like root,
steam, leaf and bud is called vegetative propagation.
2) It is performed in the potatoes with the help of 'eyes' present on the
tuber.
3) Whereas in brayophyllum it is performed with the help of buds
present on leaf margin.
4) In case of plants like sugarcane, grasses, vegetative propagation
happens with the help of bud present on nodes.
5) Plants like carrot and radish perform vegetative propagation with
the help of roots.

E) Spore formation:

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1) Fungi like mucor have filamentous body. They have sporangia.

Once the spores are formed, sporangia burst and the spores are
released.
2) Spores germinate in moist and warm place and new fungal colony is
formed.

❖ Sexual reproduction:
A. Sexual reproduction always occurs with the help of two germ cells.
B. Female gamete and male gametes are those two germ cells.
A) Gamete formation:
1) Gametes are formed by the meiosis.
2) In meiosis, chromosome number is reduced to half; hence haploid
gametes are formed.
B) Fertilization:
1) A diploid zygote is formed in this process by union of haploid male
and female gametes.
2) The zygote divides by mitosis and embryo is formed. The embryo
develops to form new individual.
3) Two parents i.e male parent and female parent are involved in this
type of reproduction.
4) Due to this, the new individual always has the recombined genes.

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5) Hence, the new individual shows similarities with the parent for
some characters and have some characters different from both
parents.
6) Diversity in living organisms occurs due to genetic variations.
7) Genetic variations helps the organism to adjust with the changing
environment and thereby to maintain their existence.
A) Sexual reproduction in plants:
1) Flower is structural unit of sexual reproduction in plants.
2) It consists of four floral whorls as calyx, corolla, androecium and
gynaecium arranged in sequence from outside to inside.
3) Androecium and gynoecium are called essential whorls because
they perform the function of reproduction whereas calyx and corolla
are called as accessory whorls because they are responsible for
protection of inner whorls.
4) Members of calyx are called as sepals and they are green colored.
5) Members of corolla are called as petals and they are variously
colored.
6) A flower is called as bisexual if both whorls i.E androecium and
gynoecium are present in the same flower. Eg. Hibiscus.
7) If only androecium is present, it is male flower and if only
gynoecium is present, flower is female flower. Eg. Papaya.
8) Many flowers have the stalk for support, called as pedicel and such
flowers are called as pedicellate whereas flower without stalk is
called as sessile.
9) Androecium is male whorl and its members are called as stamens.

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10) Gynaecium is female whorl and its membranes are called as carpels.
11) Members of gynaecium are called as carpels. These may be separate
or united.
12) Ovary is present at the basal end of each carpel. A hollow style
comes up from the ovary.
13) Stigma is present at the tip of style. Ovary contains one or many
ovules. Embryo sac is formed in each ovule by meiosis.

14) Each embryo sac consists of a haploid egg cell and two haploid polar
nuclei.
15) Pollen grains from anther are transferred to the stigma. This is called
a pollination.
16) Pollination occurs with the help of abiotic agents (wind, water) and
biotic agents (insects and other animals).
17) Stigma becomes sticky during pollination and pollen germinate
when they fall on such sticky stigma i.e a long pollen tube and two
male gametes are formed.
18) The pollen tube carries male gametes. Pollen tube reaches the
embryo sac via style.

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19) Tip of the pollen tube burst and two male gametes are released in
embryonic sac.
20) One male gamete unites with the egg cell to form zygote. This is
called fertilization.
21) Second male gamete unites with two polar nuclei and endosperm is
formed. As two nuclei participate in this process, it is called double
fertilization.
22) Ovule develops into seed and ovary into fruit after fertilization.
23) Seeds fall upon the ground when fruits break up and they germinate
in the soil under favourable conditions.
24) Zygote develops at the cost of food stored in endosperm of seed and
thus a new plantlet is formed. This is called as seed germination.

B) Sexual reproduction in human being:

1) We have studied in the chapter of heredity and variation that men
have XY sex-chromosomes and women have XX sex-chromosomes.

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2) Reproductive system with specific organs develops in the body of

men and women whereas Y-chromosomes is present in men only.
3) Now we shall study the structure and functions of human
reproductive system.
❖ Human male reproductive system:
1) Male reproductive system of humans consist of testes, various ducts
and glands.
2) Testes are present in scrotum, outside the abdominal cavity.
3) Testes contain numerous seminiferous tubules. Germinal epithelium
present in the tubules divide by meiosis to produce sperms.
4) Those sperms are sent forward through various tubules.
5) Sequence of the those tubules is as rete-testes, vas efferens,
epididymis, vas deferens, ejaculatory duct and urinogenital duct.
6) As the sperms are pushed forwards from one duct to next, they
become mature and able to fertilize the ovum.
7) Semical vesicles secrete their secretion in ejaculatory ducts whereas

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❖ Human female reproductive system:

1) All organs of female reproductive system are in abdominal cavity.
2) It includes a pair of ovaries, a pair of oviducts, single uterus and a
vagina.
3) Besides, a pair of bulbo-urethral gland is also present.
4) Generally, every month, an ovum is released in abdominal cavity
alternately from each ovary.
5) Free end of oviduct is funnel-like. An opening is present at the
centre of it. Oocyte enters the oviduct through that opening.
6) Cilia are present on inner surface of oviduct. These cilia push the
oocyte towards uterus.

❖ Gamete formation:
1) Both gametes i.E sperm and ovum are formed by meiosis. Sperms
are produced in testes of men from beginning of maturation
(puberty) till death.

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2) However, in case of women, at the time of birth, there are 2-4 million
immature oocytes in the ovary of female foetus.
3) An oocyte matures and is released from ovary every month from the
beginning of maturity up to the age of menopause (approximately
45 years of age).
4) Menopause is the stoppage of functioning of female reproductive
system.
5) At the age of about 45-50 years, secretion of hormones controlling
the functions of female reproductive system either stops of becomes
irregular. This causes the menopause.
❖ Fertilization:
1) Formation of zygote by union of sperm and ovum is called as
fertilization.
2) Fertilization is internal in humans. Semen is ejaculated in vagina
during copulation.
3) Sperms, in the numbers of few millions start their journey by the
route of vagina- uterus- oviduct.
4) One of those few million sperms fertilize the only ovum present in
the oviduct.
5) From the age of puberty up the menopause (from 10-17 years of age
up to 45-50 years), an ovum is released every month from the ovary
.I.E out of 2-4 million ova, approximately only 400 oocytes are
released up to the age of menopause.
6) Remaining oocytes undergo degeneration.

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7) Oocytes released from ovaries during last few months nearing the
age of menopause are 40-50 years old.
8) There ability of division has been diminished till now.
9) Due to this, they cannot complete meiotic division properly.
10) If such oocytes are fertilized, the new born’s produced from them
may be with some abnormalities like down's syndrome.

❖ Development and birth:

1) The zygote formed after fertilization in the oviduct, undergoes
repeated mitotic divisions and embryo is formed.
2) Meanwhile, it is pushed towards uterus.
3) Once it reaches the uterus, it is implanted and further development
occurs after implantation.
4) An organ called as placenta is formed for supply of food material
during the growth in uterus.
5) Embryonic development is completed approximately within nine
months after the fertilization.
❖ Sex determination in human being:
1) The chromosome numbers in germ cells producing the gametes are
diploid i.E 2n.
2) It includes 22 pairs of autosomes and 1 pair of sex chromosomes i.E
44 + XX or 44 + XY.

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3) These germ cells divides by meiosis. Due to this gametes contain

only haploid (n) number of chromosomes i.E 22 + X or 22 + Y.
4) Two types of sperms are produced as (22 + x) and (22 + y), whereas
oocytes are produced of only one type as (22 + x).
5) Both sperm and oocyte are produced by meiosis.
6) In case of sperms, process of meiotic division is completed before the
sperm leave male reproductive tract.
7) In case of oocyte, process of meiotic division completes after
ovulation during fertilization in oviduct.

❖ Menstrual cycle:
1) Female reproductive system undergoes some changes at puberty
and those changes repeat at the interval of every 28-30 days. These
repetitive changes are called as menstrual cycle.
2) Menstrual cycle is a natural process controlled by 4 hormones.

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3) Those 4 hormones are follicle stimulating hormone (fsh), luteinizing

hormones (lh), oestrogen and progesterone.
4) One of the several follicles in the ovary starts to develop along with
the oocyte present in it, under the effect of follicle stimulating
hormone. This secrets oestrogen.
5) Endometrium of the uterus starts to develop (during first cycle) or
regenerate (during subsequent cycles) under the effect of oestrogen.
6) The developed follicle bursts under the effect of luteinizing hormone
and oocyte is released. This is called ovulation.
7) Remaining tissues of the burst follicle forms the corpus luteum.
8) Corpus luteum starts to secrete progesterone.
9) Endometrium gland secrete their secretion under the effect of
progesterone.
10) Such endometrium is ready for the implantation of embryo.
11) If the oocyte is not fertilized within 24 hours, corpus luteum
becomes inactive and transforms into corpus albicans.
12) Due to this, secretion of oestrogen and progesterone steps
completely.
13) Endometrium starts to degenerate in absence of these two
hormones.
14) Tissues of degenerated endometrium and unfertilized ovum are
discarded out through vagina.
15) This is accompanied with continuous bleeding. This bleeding last for
5 days. This is called menstruation.

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16) Unless the oocyte is fertilized and embryo is implanted, this process
is repeated every month.
17) If the embryo is implanted, repetition of this cycle is temporarily
stopped till the parturition and thereafter period of breast feeding.
18) Menstrual cycle is a natural process and the women experience
severe pains during this process.
19) Severe weakness is felt due to heavy bleeding. There is risk of
infections as well.
20) Due to this, there is need of rest along with special personal hygiene.

❖ Reproduction and modern technology:

1) Many couples cannot have children due to various reason.

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2) In case of women, irregularity in menstrual cycle, difficulties in

oocyte production, obstacles in the oviduct, difficulties in
implantation in uterus and many other reasons are responsible for
this.
3) Absence of sperms in the semen, slow movement of sperms,
anomalies in the sperms are the reasons in case of males.
4) But now with the help of advanced medical techniques like ivf,
surrogacy, sperm bank the childless couples can have a child.
❖ In vitro fertilizations (IVF):
1) In this technique, fertilization is brought about in the test-tube and
the embryo formed is implanted in uterus of woman at appropriate
time.
2) IVF technique is used for having the child in case of those childless
couples who have problems like less sperm count, obstacles in
oviduct, etc.

❖ Surrogacy:
1) Some women have problems in implantation of embryo in uterus.

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2) Such women can take the help of the modern remedial technique
called as surrogacy.
3) In this technique, oocyte is collected from the ovary of the woman
having problem in implantation in uterus.
4) That oocyte is fertilized in test-tube with the help of sperms
collected from her husband.
5) The embryo formed from such fertilization is implanted in the
uterus of some other women having normal uterus.
6) Such a women, in whose uterus the embryo is implanted, is called as
surrogate mother.
❖ Sperm bank / semen bank:
1) There are various problems in sperm production as mentioned
above, in case of many men.
2) So as to have the children in case of such couples, new concept of
sperm bank has been introduced. This is similar to blood bank.
3) Semen ejaculated by the desired men is collected after their medical
check-up and is stored in sperm bank.
4) As per the wish of needful couple, oocyte of women of the
concerned couple is fertilized by IVF technique using the semen
from sperm bank.
5) Resultant embryo is implanted in the uterus of same women.
6) Name of the semen donor is strictly kept secret as per the law.
❖ TWINS:
1) Two embryos develop simultaneously in the same uterus and thus
two off springs are developed. Such off springs are called twins.

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2) There are two main types of twins as monozygotic twins and

dizygotic twins.
3) Monozygotic twins are formed from single embryo.
4) During early period of embryonic development (within 8 days of
zygote formation), cells of that embryo divide into two groups.
5) Those two groups develop as two separate embryos and thus
monozygotic twins are formed.
6) Such twins are genetically exact similar to each other.
7) Hence, there gender is also same.
8) In case of monozygotic twins, if the embryonic cells are divided into
two groups 8 days after the zygote formation, there is high
possibility of formation of conjoined twins (siamese twins).
9) Such twins are born with some parts of body joined to each other.
10) Some organs are common in such twins.

11) Occasionally, two oocytes are released from the ovary of women
and both oocytes are fertilized by two separate sperms and thus two
zygotes are formed.
12) Those two embryos are separately implanted in the uterus and thus
dizygotic twins are delivered after complete development.
13) Such twins are genetically different and may be of different gender.

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❖ Reproductive health:
1) A person's state of being physical, mental and social strongness is
called as health.
2) Occurrence of menstrual cycle is related with reproductive and
overall health of women.
3) Personal hygiene is very important during those days.
4) Among the various sexual diseases, syphilis and gonorrhoea occur
on large scale.
5) Both of these causes due to bacteria.
6) Occurrence of chancre (patches) on various parts of body including
genitals, rash, fever, inflammation of joints, alopecia, etc. Are the
symptoms of syphilis.
7) Painful and burning sensation during urination, oozing of pus
through penis or vagina, inflammation of urinary tract, anus, throat,
eyes, etc. are symptoms of gonorrhoea.

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SYPHILIS

GONORRHOEA

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4. Heredity and Evolution

❖ What is ecosystem?
1) Paddy is cultivated on large scale in various states of South India.
Paddy fields are frequently attacked by grasshoppers.
2) Similarly, frogs are also present in large number in the mud of
paddy fields, to feed upon grasshoppers and snakes are also present
therein to feed upon their favorite food- frogs.
3) However, if frog population declines all of a sudden
❖ Relationship between Environment and Ecosystem:
1) There are two main types of environment. One is natural
environment and other is artificial environment.

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2) Natural environment consists of air, atmosphere, water, land, living

organisms, etc. Continuous interactions occur between biotic and
abiotic factors.
3) Their interactions are very important.
4) Artificial environment is also affecting the natural environment
directly or indirectly.
5) Basically, environment consists of two basic factors- 1. Biotic factors,
2. Abiotic factors.
6) The science that deals with the study of interactions between biotic
and abiotic factors of the environment is called as ecology.
7) Basic functional unit used to study the ecology is called as
ecosystem.
❖ Environmental Conservation:
1) Generally, contamination of any material is its pollution.
2) Unnecessary and unacceptable change in the surrounding
environment due to natural events or human activities is called as
environmental pollution.
3) Direct or indirect changes in physical, chemical and biological
properties of air, water and soil which will be harmful to human and
other living beings is environmental pollution.
❖ Radioactive pollution:
1) Radioactive pollution can occur due to two reasons as natural and
artificial.
2) UV and IR radiations are natural radiations whereas X-rays and
radiations from atomic energy plants are artificial radiations.

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3) Chernobyl, Windscale, and Three Miles Island mishaps are the

major mishaps of the world till present.
4) Thousands of people have been affected for long term due to these
accidents. Some of the effects of radiations are as follows
1. Cancerous ulceration occurs due to higher radiations of X-rays.
2. Tissues in the body are destroyed.
3. Genetic changes occur.
4. Vision is adversely affected.
❖ The big story of a small man:
Jadav Molai Payeng is a highly capable person in Assam. Born in 1963,
he is working as a forest worker since the age of 16 years. He has been
awarded with the prestigious ‘Padmashree’ award by government of
India for this unparallel work. Now, it is well known as ‘Molai Jungle’.
❖ Environmental Conservation and Biodiversity:
1) Biodiversity is the richness of living organisms in nature due to
presence of varieties of organisms, ecosystems and genetic
variations within a species.
2) Biodiversity occurs at three different levels.
❖ Genetic Diversity:
1) Occurrence of diversity among the organisms of same species is
genetic diversity. Ex. Each human being is different from other.
2) Possibility of wiping out the species arises if there is decrease in the
diversity within the species whose members involve in sexual
reproduction.
❖ Species Diversity:

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1) Innumerable species of organisms occur in the nature. This is called

as species diversity.
2) Species diversity includes various types of plants, animals and
microbes.
❖ Ecosystem Diversity:
1) Ecosystem is formed through the interaction between plants,
animals, their habitat and changes in the environment.
2) Each ecosystem has its own characteristic animals, plants, microbes
and abiotic factors.
3) Ecosystems are also of two types are natural and artificial.

Genetic Diversity

Species biodiversity

❖ How can biodiversity be conserved?

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1) Protecting the rare species of organisms.

2) Establishing national parks and sanctuaries.
3) Declaring some regions as ‘bioreserves’.
4) Projects for conservation of special species.
5) Conserving all plants and animals.
6) Observing the rules.
7) Maintaining record of traditional knowledge.
❖ Hotspots of Biodiversity
1) 34 highly sensitive biodiversity spots are reported all over the world.
2) Such areas had once occupied 15.7% area of the Earth. At present,
86% of the sensitive areas are already destroyed.
3) Presently, only 2.3% area of the Earth has been left over with
sensitive spots. It includes 1,50,000 plant species which are 50% of
the world count.
4) As far as India is considered, out of 135 species of animals, 85
species are found in the jungles of eastern region.
5) About 1,500 endemic plant species are found in western ghat. Out of
the total plant species in the entire world, 50,000 are endemic.
❖ Classification of Threatened Species:
1) Endangered Species:
Either number of these organisms is declined or their habitat is shrunk
to such an extent that they can be extinct in near future if conservative
measures are not implemented. Example, Lion tailed monkey, lesser
florican.

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2) Rare Species:
Number of these organisms is considerably declined. Organisms of
these species being endemic may become extinct very fast. Example,
Red panda, Musk deer.

Red panda Musk deer

❖ Vulnerable Species:
Number of these organisms is extremely less and continues to decline.
Continuous decline in their number is worrisome reason. Example,
Tiger, Lion. Recall a little International Union for Conservation of
Nature (IUCN) prepares the ‘Red List’ that contains the names of
endangered species from different countries. Pink pages of this book

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contain the names of endangered species while green pages contain

the names of previously endangered but presently safe species.
❖ Indeterminate Species:
These organisms appear to be endangered but due to their some
behavioral habits (like shyness) there is no definite and substantial
information. Example, Giant squirrel (Shekhru).

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5. Towards green energy

❖ Energy and use of energy:

1) In modern civilization, energy has become a primary need along
with food, cloth and shelter.
2) We need energy in different forms for diverse types of works.
3) The energy that we need may be in the form of mechanical energy,
chemical energy, sound energy, light energy or heat energy.
4) We know that energy can be converted from one form to another
(kinetic energy to potential energy).
5) Here we will learn about various sources that are now used for the
generation of electrical energy.
❖ Electromagnetic induction:

1) Take a loop of wire, connect it with galvanometer to see the flow of

current in it.
2) Place a bar magnet near the loop of wire connected to galvanometer.
3) Move the magnet near to loop and observe what happens?

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4) When the magnet comes near the loop the galvanometer shows
deflection.
5) This is due to the flow of current in the loop.
6) This current is produced due to the flow of magnetic field around
the magnet which keeps on changing every minute.

With battery.

1) When this loop is brought near a circuit which is connected to

battery and a switch.
2) The time when switch is on and current starts to flow in a circuit, the
another loop with galvanometer shows deflection and then stops.
3) This is because, when the current starts to flow there is magnetic
field produced which happens to form current flow in the another
loop and as the current and magnetic field produced remains same,
the galvanometer stops deflecting. This is electromagnetic induction.
4) Using this method, a potential difference can always be created and
hence is used in electric generator.
5) Such large generators are used in commercial power generating
plants.
6) Turbine is used to rotate the magnet in the generator.
7) Turbine has blades. When a flow of liquid or gas is directed on the
blades of the turbine, it rotates because of flow of kinetic energy.

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8) This turbine is connected to electric generator. Thus the magnet in

electric generator starts rotating and electric energy is produced.
❖ Types of generator:

1) To generate electricity based on the principle of electromagnetic

induction, we need a generator.
2) To rotate the generator we need a turbine and to drive the turbine,
we need an energy source.
3) Based on which type of energy source is used to rotate the turbine,
there are different types of power generating stations.
4) The design of turbine used in different types of power station is also
different.
❖ Thermal energy based electric power station:
1) In this the turbine is rotated using steam. Water is heated in boiler.
2) Using the thermal energy released due to burning of coal, steam of
very high temperature and pressure is generated.
3) The energy in the steam drives the turbine.

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4) Thus, the generator connected to the turbine rotates and electrical

energy is produced.
5) The steam is converted back into water and the water is re-circulated
to the boiler
6) Since thermal energy is used here to generate electrical energy, such
power plants are called thermal power plants.
7) In thermal power plant, the chemical energy in the coal is converted
into electrical energy through several steps which are as follows.

8) After combustion of fuel (here, coal) in the boiler, the emitted gases
are released to the atmosphere through very high tower.
9) once the turbine is rotated using the steam at high temperature and
high pressure, steam temperature and pressure decreases.
10) this steam is converted back to water by taking out heat from it (i.e
by cooling it)
11) this is done in the condenser using water in the cooling tower.
12) the water in cooling tower is circulated through the condenser.
13) heat energy in the steam is given to the water and the steam
condenses back to water.
14) the heat absorbed by the water is then released to atmosphere
through vapour and heated air through cooling tower.

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15) Although, thermal power generation is a major way of electricity

generation today.

❖ Problems:
1) Air pollution due to burning of coal; burning of coal results in
emission of gases like carbon dioxide, sulphur oxide and nitrogen
oxide which are harmful to the health.
2) Along with the emission of gases due to burning of coal, soot
particles (carbon particles) are also released to environment.
3) This may cause serious health problems related to the respiratory
system.
4) The reserves of fuel used in this method i.e coal are limited.
5) Therefore, in future there will be limitations on the availability of
coal.

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❖ Power plant based on nuclear energy:

1) In the power plant based on nuclear energy also, steam turbine is
used to rotate the generator.
2) Here, the energy released by fission of nuclei of atoms like uranium
or plutonium is used to generate the steam of high temperature and
high pressure.
3) The energy in the steam rotates the turbine, which in turn drives the
generator producing electricity.
4) Thus, here the nuclear energy is converted into thermal energy.
5) Thermal energy is converted into kinetic energy of steam, kinetic
energy of steam is converted into kinetic energy of turbine.
6) Then the kinetic energy of turbine is converted into electrical energy.
7) When electron is bombarded on an atom of uranium-235, it absorbs
the neutron and converts into its isotope uranium-236.
8) Uranium-236 being extremely unstable converts into atoms of
Barium-141 and krypton-92. three neutrons are released as energy of
200 MeV (millielectron volt) i.e 0.2 eV.

9) The three neutrons generated in this process cause fission of three

other uranium-235 atoms releasing more energy.
10) This process of fission of uranium-235 atoms continues and is called
the chain reaction.
11) In nuclear power plant, a controlled chain reaction results in release
of thermal energy, which is used for electrical energy generation.

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12) A nuclear power plant does not use fossil fuel like coal.
13) Therefore, problems like air pollution do not arise.
14) Also, if sufficient nuclear fuel is available, this can be a good source
of electrical energy.

❖ PROBLEMS:
1) The products after fission of nuclear fuel are also radioactive and
emit harmful radiations. This products are called nuclear waste.
2) How to dispose the nuclear waste safely is a big challenge before the
scientists.
3) An accident in nuclear power plant can be very fatal. This is because
the accident may result in release of very harmful radiations.
❖ Power generation plant based on energy of natural gas:
1) In this plant, the turbine is run by a gas at very high temperature
and pressure generated by combustion of natural gas.
2) There are three main sections in this type of plant.
3) Pressurized air is introduced in the combustion chamber using a
compressor.
4) In the combustion chamber the natural gas burns in presence of air.

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5) The gas at very high temperature and pressure generated in this

chamber runs the turbine. the turbine then drives the generator to
produce electricity.
6) The efficiency of this type of power generation plant is higher than
that of power generation plant based on coal.
7) Since, the natural gas does not contain sulphur, burning of natural
gas results in less pollution.

❖ Electric generation and environment:

1) Electricity based on fossil fuels like coal, natural gas and nuclear
fuels like uranium and plutonium are not environmental friendly.
2) We have seen that burning of fossil fuels like coal, and natural gas
leads to emission of certain gases and soot particles.
3) This results in air pollution. Incomplete combustion of fuel leads to
formation of carbon monoxide.
4) Increase in percentage of carbon dioxide in the air due to burning of
fuel affects environment.

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5) The phenomena of global warming is an example of this.

6) Nitrogen dioxide generated leads to problems like acid-rain.
7) It can lead to problem like respiratory system, like asthama.
8) It takes millions of years for formation of fossil fuels like coal, crude
oils and natural gas (LPG)/(CNG).
9) Also, they are limited. It is said that with the current speed of their
use, the coal reserves in the world would last for another about 200
years or so the natural gas reserves for about 200-300 years.
10) We have also discussed the accidents due to nuclear power plants.
❖ Hydroelectric energy:
1) Kinetic energy in flowing water or the potential energy in water
reservoir is a conventional source of energy.
2) in hydroelectric power plant, the potential energy in water stored in
dam is converted into kinetic energy of water.
3) fast flowing is brought from the dam to the turbine at the bottom of
the dam. the kinetic energy of the flowing water drives the turbine.
4) the turbine in turn drives the generator to generate electricity.

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❖ Merits and Demerits of hydroelectric power plants:

MERITS DEMERITS
1. Since, no fuel is burnt in this, The back-water due to storage of
there is no pollution. water in dam may submerge
villages or towns, forests, fertile
land.
2. If there is sufficient water The obstruction of the flow of
storage we can generate river water may have adverse
electricity as per our need. effect on living world in water.
3. It can be replenished during
rainy season leading to
uninterrupted power
generation.

❖ Electric generator using wind energy:

1) The machine which converts the kinetic energy of wind to electrical
energy is called wind-turbine.
2) As the wind strikes blade of the turbine, the blades rotate.
3) The axel of turbine is connected to electric generator through a gear-
box.
4) The function of gear box is to maintain the speed of rotations per
unit time.

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5) Hence, the generator works and electricity is formed.

6) Wind turbines with capacity less than 1 kw to 7 kw (7000 kw).
7) The wind velocity at specific location depends upon its geographical
factors.
8) Wind energy is a clean energy source.

❖ Electric energy generation using solar energy:

1) Using the energy in sunlight, electric energy can be generated in two
ways:
2) Electrical energy can be directly generated from solar radiation,
without using generator and electromagnetic induction.
3) This happens in solar photovoltaic cells.
4) In the second method, the energy in solar radiation is converted into
thermal energy first, then the turbine-generator system is used.
A) Solar photovoltaic cells:

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1) Solar photovoltaic cells converts solar radiation into electric energy

directly. This is called solar photovoltaic effect.
2) This electric energy is in dc form.
3) These solar cells are made up of specific type of materials called as
semiconductors (silicon).
4) A silicon cell of dimension 1 cm2 generates current of about 30 ma
and potential difference of about 0.5v.
5) Thus, a silicon solar cell of dimension 100 cm2 will generate about 3a
(30 ma/cm2 x 100 cm2 = 3000 ma = 3a) current and 0.5v.
6) Potential difference available from a solar cell is independent of its
area.
7) If the solar cells are connected in series then the potential difference
will be added, but the current flowing through it will not be added.
8) If the solar cells are connected in parallel then the current will be
added and potential difference will remain the same.

9) If we arrange these solar cells in series as well as parallel, we can

obtain as much as electricity we need. This method is used in
industries.

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10) Here, the current produced is in DC form and most of the appliances
works on AC form, so we need to convert it into AC form.
11) The device which does this is called inverter.

B) Solar thermal power plant:

1) solar radiations are used to produce thermal energy and the steam
with high pressure is used to rotate the turbine and then the
generator and current is produced.
2) to produce thermal energy reflectors are used.

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QUESTION:
❖ One solar panel produces a potential difference of 18 V and
current of 3 A. describe how you can obtain a potential difference
of 72 volts and current of 9 A with a solar array using solar panels.
Ans:

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6. Animal classification

❖ History of animal classification:

1) Greek philosopher Aristotle was the first to perform the animal
classification.
2) Aristotle classified the animals according to the criteria like body
size, habits and habitats. Classification proposed by Aristotle is
known as ‘Artificial method’.
3) Besides Aristotle, artificial method of classification was followed by
Theophrastus, Pliny, John Ray, Linnaeus, etc.
4) Later on, ‘Natural system of classification’ was followed. Natural
system of classification was based on various criteria like body
organization, types of cells, chromosomes, bio-chemical properties,
etc.
5) By the time, system of classification based on evolution was also
brought into practice. It was used by Dobzhansky and Meyer.
6) Recently, Carl Woese has also proposed the animal classification
❖ Benefits of animal classification:
1) Study of animals becomes convenient.
2) Study of few animals from a group helps to understand about that
entire animal group.
3) It gives idea about animal evolution.
4) Animals can be easily identified with great accuracy.

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5) It helps to understand the relationship of animals with other living

organisms.
6) It helps to understand the habitat of each animal and it’s exact role
in the nature.
7) It helps to understand various adaptations shown by animals.
❖ Traditional method of animal classification:
Traditionally, depending upon presence or absence of the notochord,
the animal kingdom has been divided into two groups- Non-chordates
and Chordates.
A) Non-Chordates :
1) Body is not supported by rod-like notochord.
2) Pharyngeal gill-slits are absent.
3) Nerve cord; if present, it is on ventral side. It is solid & paired.
4) Heart, if present, it is on dorsal side.
B) Chordates :
1) Body is supported by notochord.
2) Pharyngeal gill-slits or lungs are present for respiration.
3) Nerve cord is present on dorsal side of body. It is hollow.
4) Heart is present on ventral side of body.
5) Notochord is a long rod like supporting structure present on dorsal
side of animal body. It keeps the nerve tissue isolated from
remaining body.

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❖ At present, according to the five kingdom classification system of

Robert Whittaker, all multicellular animals are included in
Kingdom: Animalia. This system of classification is based upon
some criteria like Body organization, Body symmetry, Body cavity,
Germinal layers, Segmentation, etc

❖ Criteria for new system of classification:

A) Grades of organization:

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1) Body of animals is made up of cells. In case of multicellular animals,

many cells are performing different functions in their body.
2) In case of multicellular animals, if tissues are not formed, their body
organization is called as ‘Cellular grade organization’. Ex. Phylum-
Porifera.
3) In case of some animals, cells come together to form tissues with the
help of which all the body functions are performed. Such animals
show ‘Cell – tissue grade’ organization. Ex. Animals from phylum-
Cnidaria.
4) Flat worms show ‘Tissue Organ grade’ organization. In this type of
organization, tissues are organized to form some organs. However,
complete organ systems are not formed.
5) In unicellular organisms all the functions of life are performed by
same cell. Body organization of these unicellular organisms is called
‘protoplasmic grade’ of organization
6) Besides the four types of body organizations mentioned above,
remaining all animals show ‘Organ – system grade organization’ in
which different organs are joined together to form organ system that
performs specific functions. Ex. Crab, Frog, Human, etc

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B) Body Symmetry:
In imaginary sense, if body of any animal is cut through imaginary axis
of body, it may or may not produce two equal halves. Depending upon
this property, there are different types of animal bodies.
1. Asymmetrical Body : In case of such body, there is no any such
imaginary axis of the body through which we can get two equal
halves. Ex. Some sponges.
2. Radial symmetry : In this type of body, if imaginary cut passes
through central axis but any plane of body, it gives two equal
halves. Ex. Star fish. In case of this animal, there are five different
planes passing through central axis of body through which we can
get two equal halves.
3. Bilateral symmetry: In this type of body, there is only one such
imaginary axis of body through which we can get two equal halves.
Ex. Insects, fishes, frog, birds, human, etc.

C) Germ Layers: Diploblastic and Triploblastic:

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1) In case of multicellular animals, germ layers are formed during

initial period of their embryonic development and from those germ
layers only, different tissues are formed in the body.
2) In case of some animals, only two germ layers [Endoderm &
ectoderm] are formed.
3) Ex.: All Cnidarians. In most of all the remaining animals, three germ
layers are formed i.e. mesoderm besides endoderm & ectoderm.

D) Body cavity (Coelom):

1) Cavity between the body wall and internal organs is called as body
cavity/coelom.
2) In case of multicellular animals, during initial period of their
embryonic development, body cavity is formed from either
mesoderm.
3) Such type of body cavity is present in animals of phylum Annelida
and all phyla coming after Annelida.
4) Such animals are called as EU coelomate (animals with true body
cavity). Body cavity is absent in case of animals from phyla Porifera,
Cnidaria and Platyhelminthes.

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5) Such animals are called as acoelomate. In case of animals from

phylum Aschelminths, they have body cavity but it is not formed by
the above mentioned two ways.
6) Hence those animals are called as pseudocoelomates.

E) Body Segmentation:
1) If the body of animals is divided into small, similar units, then such
body is called as segmented body and each small unit is called as
segment.
2) Ex. Animals like earthworm from phylum Annelida

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I) Phylum- Porifera
1. These animals are with simplest body plan and are called as
‘Sponges’. They bear numerous pores on their body. Those pores are
called as ‘Ostia’ and ‘Oscula’.
2. These are aquatic animals. Most of them are marine and few are
fresh water dwellers.
3. Most of the animals have asymmetrical body.
4. These animals have special types of cells- collar cells.
5. These animals are always attached to substratum, hence do not
show locomotion. Hence, they are referred as sedentary animals.
6. Their spongy body is supported by spicules or spongin fibres.
Spicules are made up of calcium carbonate or silica.
7. These animals feed upon small organisms taken in their body along
with water. Water is taken in through ostia and given out through
oscula.
8. These animals reproduce by budding, an asexual method and / or
by sexual method. Besides, they have good ability of regeneration.
9. Examples: Sycon, Euspongia (Bath sponge), Hyalonema, Euplectella,
etc.

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Sycon Euspongia (Bath sponge)

Hyalonema Euplectella

II) Phylum – Coelenterata/Cnidaria:

1. Body of these animals is cylindrical or umbrella-like. If it is
cylindrical, it is called as ‘Polyp’ and if it is umbrella like, it called as
‘Medusa’.

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2. Most of these animals are marine. Only few are fresh-water

dwellers.
3. Body of these animals is radially symmetrical & diploblastic.
4. Cnidoblast bearing tentacles are present around the mouth.
5. Tentacles are useful for capturing the prey whereas cnidoblasts
inject the toxin in the body of prey. Those are useful for protection
too.
6. Examples: Hydra, Adamsia (Sea anemone), Physalia (Portuguese-
man-of war), Aurelia (Jelly fish), Corals, etc.

Hydra

Physalia Aurelia (Jelly fish) Adamsia (Sea anemone)

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Corals Tentacles

III) Phylum – Platyhelminthes:

1. Body of these animals is slender & flat like a leaf or strip. Hence,
they are called as ‘flatworms’.
2. Most of these animals are endoparasites. Few are free-living &
aquatic.
3. Body is acoelomate & bilaterally symmetrical.
4. These are triploblastic i.e. their body is made up of three germ
layers- endoderm, ectoderm & mesoderm.
5. These animals are hermaphrodite i.e. male and female reproductive
systems are present in the same animal body. Examples: Planaria,
Liver fluke, Tape worm, etc.

Liver fluke Planaria

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Tape
worm

IV) Phylum- Aschelminthes:

1. Body of these animals is long thread-like or cylindrical. Hence, they
are called as round worms.
2. These animals are either free living or endoparasites. Free living
animals are either aquatic or terrestrial.
3. Body of these animals is triploblastic and pseudocoelomate.
4. Body of these animals is non-segmented and covered with tough
cuticle.
5. These animals are unisexual. Examples: Ascaris (Intestinal worm),
Filarial worm, Loa loa (Eye worm), etc.

Ascaris (Intestinal worm)

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Filarial worm Loa loa (Eye worm)

V) Phylum – Annelida:
1. Body of these animals is long, cylindrical & metamerically
segmented.
2. Most of the animals are free-living, but few are ectoparasites. Free-
living animals may be marine or fresh water dwellers or terrestrial.
3. These animals are triploblastic, bilaterally symmetrical and
eucoelomate.
4. They have setae or parapodia or suckers for locomotion.
5. Their body is covered with special cuticle.
6. These animals are either hermaphrodite or unisexual. Examples:
Earthworm, Leech, Nereis, etc.

Earthworm Leech Nereis

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VI) Phylum- Arthropoda:

1. These animals have jointed appendages. Hence they are called as
arthropods.
2. Planet Earth has highest number of animals from this phylum.
Hence, this is largest phylum with highly successful animals in
animal kingdom.
3. These animals are found in all types of habitats ranging from
deepest oceans to highest mountains.
4. Body of these animals is triploblastic, eucoelomate, bilaterally
symmetrical and segmented.
5. Chitinous exoskeleton is present around their body.
6. These animals are unisexual. Examples: Crab, spider, scorpion,
millipede, centipede, cockroach, butterfly, honey bee, etc.

millipede centipede

VII) Phylum- Mollusca:

1. Body of these animals is soft and slimy. Hence they are referred as
mollusc.
2. This is second largest phylum in animal kingdom.
3. These animals are aquatic or terrestrial. Most of the aquatic molluscs
are marine, but few are fresh water dwellers too.

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4. Body of these animals is triploblastic, eucoelomate, non-segmented

and soft. Except animals like snail, their body shows bilateral
symmetry. Their body is divided into three divisions like head, foot
and visceral mass.
5. Visceral mass is covered with mantle. This mantle secretes a hard,
calcareous shell. This shell may be external or internal or even
absent in some cases.
6. These animals are unisexual. Examples: Bivalve, Snail, Octopus, etc.

Bivalve Snail Octopus

VIII) Phylum- Echinodermata:

1. Calcareous spines are present on the body of these animals; hence
they are called as echinoderms.
2. These animals are found only in ocean.
3. Their body is triploblastic, eucoelomate. And it is radially
symmetrical in adult stage. However, they show bilateral symmetry
in larval stage.
4. They perform locomotion with the help of tube-feet. Tube feet are
also useful for capturing the prey. Some animals are sedentary.
5. They have skeleton made up of calcareous spines and / or ossicles
(plates).
6. These animals have good ability of regeneration.

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7. These animals are mostly unisexual. Examples: Star fish, sea-urchin,

brittle star, sea-cucumber, etc.

sea-urchin brittle star sea-cucumber

IX) Phylum- Hemichordata:

1. Body of these animals is divided into three parts as proboscis, collar
& trunk.
2. Notochord is present in proboscis region only. Hence, they are
called as hemichordates.
3. These animals are also called as ‘acorn worms’.
4. These are marine animals, live in burrows in sand.
5. They have one to many pharyngeal gill slits.
6. They are unisexual or some may be hermaphrodite. Ex.:
Balanoglossus, Saccoglossus.

Balanoglossus Saccoglossus

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X) Phylum- Chordata:
These animals have supporting notochord in their body. All chordates
are included in the same phylum. The phylum Chordata is classified in
to three subphyla.
1. Notochord is present in the body during at least any developmental
stage.
2. Pharyngeal gill slits are present in the body during at least any
developmental stage.
3. Single, tubular spinal cord is present on dorsal side of body.
4. Heart is present on ventral side of body.
A. Sub phylum – Urochordata:
1. These are marine animals.
2. Their body is covered by skin-like test or tunic.
3. Larvae of these animals are freely swimming and notochord is
present in only tail region of larvae. Hence, they are called as
Urochordata.
4. Larvae metamorphose into adults after settling down at bottom of
the sea.
5. Generally, these animals are hermaphrodite.
6. Examples: Herdmania, Doliolum, Oikopleura, etc.

Herdmania Doliolum Oikopleura

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B. Sub phylum -Cephalochordata

1. These are small, fish-like, marine animals.
2. Notochord is present throughout the body length.
3. Pharynx is very large and contains gill-slits.
4. These animals are unisexual. Ex.: Amphioxus.

C. Sub phylum -Vertebrata/Craniata

1. In these animals, notochord is replaced by vertebral column.
2. In these animals, head is well developed.
3. Brain is protected by cranium.
4. Endoskeleton is either cartilaginous or bony.
5. Some chordates are jaw-less (Agnatha) whereas some are with jaws
(Gnathostomata).

Agnatha

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Gnathostomata

❖ Subphylum- Vertebrata is divided into six classes as follows:

I) Class- Cyclostomata
1. These animals have jaw-less mouth provided with sucker.
2. Their skin is soft and without any scale.
3. Paired appendages are absent.
4. Endoskeleton is cartilaginous.
5. Most of the animals are ectoparasites. Examples: Petromyzon,
Myxine, etc.

Petromyzon Myxine

II) Class- Pisces

1. These are cold blooded (Poikilotherms) aquatic animals living in
marine and fresh waters.
2. Body is spindle shaped to minimize water-resistance.

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3. They have paired & un-paired fins for swimming. Tail fin is useful
as a steering organ during swimming.
4. Exoskeleton is in the form of scales & endoskeleton is either
cartilaginous or bony.
5. Respiration occurs with gills. Examples.: Rohu, Pomfret, Sea horse,
Shark, Electric ray, Sting ray, etc.

Electric ray Sting ray

III) Class- Amphibia

1. These animals are strictly aquatic during larval life and perform
only aquatic respiration whereas they can live in water as well as on
land during adult life and can perform aquatic as well as aerial
respiration.
2. They have two pairs of appendages. Digits are without claws.
3. Exoskeleton is absent. Skin is without any derivative and usually
kept moist for respiration.
4. External ear is absent but tympanum is present.
5. Neck is absent. Eyes are prominent with eye lids. Ex.: Frog, Toad,
Salamander, etc.

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Salamander Toad Frog

IV) Class- Reptilia

1. According to the course of animal evolution, these are first true
terrestrial animals with creeping movement.
2. These are cold blooded (poikilotherms) animals.
3. They creep on the land as their body cannot be lifted up.
4. Their skin is dry and scaly.
5. Neck is present between head & trunk.
6. External ear is absent.
7. Digits are provided with claws.
8. Examples: Tortoise, Lizard, Snake, etc.

V) Class- Aves
1. These vertebrates are completely adapted for aerial life.
2. These are warm blooded (Homeotherms) i.e. they can maintain their
body temperature constant.

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3. Their body is spindle-shaped to minimize air resistance during

flight.
4. Forelimbs are modified into wings. Digits are covered with scales
and bear claws.
5. Exoskeleton is present in the form of feathers.
6. Neck is present between head and trunk.
7. Jaws are modified into beak.
8. Examples: Peacock, Parrot, Pigeon, Duck, Penguin, etc.
VI) Class- Mammalia
1. Presence of mammary glands is typical character of mammalia.
2. These animals are warm blooded.
3. Body is divided into head, neck, trunk and tail.
4. Digits are provided with nails, claws, or hooves.
5. Exoskeleton is in the form of hairs or fur.
6. Examples: Elephant, Human, Kangaroo, Dolphin, Bat, etc.

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7. Introduction to microbiology

❖ Industrial Microbiology:
Main features Industrial Microbiology: main features
A. Various productions with the help of fermentation process. Ex. Bread,
cheese, wine, raw material for chemicals, enzymes, nutrients, medicines,
etc.
B. Use of microbes for garbage management and pollution control.
❖ Products:
A. Dairy Products:
1. Since ancient days, milk is converted into various products for its
preservation purpose. Ex. Cheese, butter, cream, kefir, yoghurt, etc.
2. Water content and acidity of the milk changes during formation of
these products and texture, taste and flavor is improved.
3. For production of most of the milk products, bacteria in milk itself
are used; only cheese is produced with the help of fungi.
4. Basic process for production of yoghurt, cheese and cream is same.
Milk is pasteurized at the beginning to destroy unwanted microbes.
5. It is then fermented with the help of lactobacilli.
6. In this process, lactose sugar of the milk is converted into lactic acid
and milk proteins are coagulated with the help of lactic acid.

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7. Besides, compounds with taste and flavor are also formed. Ex.
Diacetyl has the flavor of butter.
B. Yoghurt Products:
1. Yoghurt is a milk product produced with the help of lactobacilli
(inoculant).
2. For maintaining the protein content, condensed milk powder is
mixed with milk to be fermented for industrial production of
yoghurt.
3. Milk is boiled and once it cools to warm temperature, bacterial
strains of Streptococcus thermophilus and Lactobacillus delbrueckii
are added to it in 1:1 proportion.
4. Lactic acid is formed due to Streptococcus that makes the proteins to
gel out that gives dense consistency to the yoghurt.
5. Acetaldehyde like compounds are formed due to lactobacilli that
gives characteristic taste to the yoghurt.
6. Now a day, various fruit juices are mixed with yoghurt to impart
different flavors. Ex. Strawberry yoghurt, banana yoghurt, etc.
7. Shelf life of yoghurt and its probiotic properties can be improved by
pasteurization.
C. Butter:
1. Two types of butter like sweet cream and cultured are produced on
large scale. Microbes are used for production of cultured variety.
D. Cheese production:

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1. First, chemical and microbiological tests of milk are performed.

Some colors and microbes like Lactobacillus lactis, Lactobacillus
cremoris, and Streptococcus thermophilus are mixed with milk.
2. It imparts sourness to the milk. After this, to impart the dense
texture, whey (water in yoghurt) needs to be removed.
3. An enzyme, rennet obtained from alimentary canal of cattle was
being traditionally used earlier.
4. However, an enzyme protease obtained from fungi is used at
present to produce vegetarian cheese.
5. The whey is separated from yoghurt (which has some other uses).
6. During industrial production of milk products, strict cleanliness and
sterilization is essential as bacteria can be attacked by viruses.
7. Hence, virus-resistant varieties of bacteria are developed.
8. Recently, use of mutant varieties of bacteria has been increased.
Artificially, some strains are developed that will help to avoid
unnecessary steps / materials.
9. Freshly prepared cheese is always soft e.g. cottage cheese, cream
cheese, mozzarella cheese. On storing for 3 to 12 months, semi-hard
cheddar cheese is formed whereas after ripening for 12 – 18 months,
very hard cheese called parmesan cheese is formed.
10. 7.1 Cheese and Butter like cutting the solid yoghurt into pieces,
washing, rubbing, salting, and mixing of essential microbes, pigments
and flavors.
11. Then, cheese is pressed and cut in to pieces and stored for ripening.
❖ Bread

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1. Different types of breads are produced from flour of cereals. Dough

is formed by mixing of baker’s yeast – Saccharomyces cerevisiae,
water, salt and other necessary materials with flour.
2. Due to fermentation of carbohydrates by yeast, sugar is converted in
to carbon dioxide (CO2) and ethanol.
3. Dough rises up due to CO2 and the bread becomes spongy.
Compressed yeast is used in commercial bakery industry.
4. It is available in dry, granular form for domestic use.
5. Yeast produced for commercial use contains various useful contents
like carbohydrates, fats, proteins, various vitamins, and minerals.
6. Due to this, bread and other products produced with the help of
yeast become nutritive.
7. Ingredients like vinegar, soya sauce and monosodium glutamate
(ajinomoto) that are used in presently popular chinese food are
produced by microbial fermentation.
❖ Probiotics:
1. These are also milk products, but contain active bacteria e.g.
Lactobacillus, Acidophilus, Lactobacillus casei, Bifidobacterium
bifidum, etc.
2. These microbes maintain the balance of intestinal microorganisms
i.e. increase the population of microbes helping the digestion and
decrease the population of harmful microbes (ex. Clostridium).
3. Probiotic products are available in various forms like yoghurt, kefir,
sauerkraut (pickle of cabbage), dark chocolate, miso soup, pickles,

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oils, corn syrup, artificial sweeteners, microalgae (Sea food like

Spirulina, Chlorella, Blue green algae, etc.).
4. These products form the colonies of useful microbes in alimentary
canal and control other microbes and their metabolic activities,
improve resistance and lower the ill-effects of harmful substances
formed during metabolic activities.
5. Useful microbes become inactive due to antibiotics; probiotics make
them active again.
6. Nowadays, probiotics are used for treatment of diarrhea and
treatment of poultry also.
❖ Vinegar Production:
1. Vinegar is used in each country of the world to impart sour taste to
food materials and for preservation of pickles, sauce, ketch-up,
chutneys, etc.
2. Chemically, vinegar is 4% acetic acid (CH3 COOH).
3. Ethanol, an alcohol is obtained by fermentation of carbon
compounds like fruit juices, maple syrup, sugar molasses, starch of
the roots; with the help of yeast Saccharomyces cerevisiae.
4. Mixture of bacterial strains like Acetobacter and Glucanobacter is
mixed with ethanol for its microbial degradation.
5. Acetic acid and other by-products are obtained through it.
6. Acetic acid is separated from mixture by rarefaction.
7. Acetic acid is bleached with the help of potassium ferrocynide.
Then, it is pasteurized. Finally, very small quantity of SO2 gas is
mixed to produce vinegar.

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8. Soya sauce is produced by fermentation of the mixture of flour of

wheat or rice and soyabean with the help of the fungus Aspergillus
oryzae
❖ Microbial Enzymes:
1. These enzymes are active at low temperature, pH and pressure; due
to which energy is saved and erosion-proof instruments are also not
necessary.
2. Enzymes carry out specific processes; hence unnecessary byproducts
are not formed due to which expenses on purification are
minimized.
3. Such enzymes are eco-friendly. Some examples of microbial
enzymes are oxidoreductases, transferases, hydrolases, lyases,
isomerases, ligases, etc.
4. Process of dirt / muck removal occurs at low temperature too due to
mixing of enzymes with detergents.
5. Glucose and fructose syrup can be obtained from corn flour by
action of enzymes obtained from bacilli and streptomyces.
6. Microbial enzymes are used in various industries like cheese, plant
extracts, textile, leather, paper, etc.
7. Wheat or rice flour is inoculated with Aspergillus.
❖ What is the xanthan gum that imparts thickness to your favourite
ice creams, puddings, chocolates, milk shakes, chocolate drinks,
instant soups, etc.?
1. This gum is obtained by fermentation of starch and molasses with
the help of Xanthomonas species.

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2. It is variously useful due to properties like solubility in hot and cold

water, high density, etc.
3. It is used for production of pigments, fertilizers, weedicides, textile
pigments, tooth pastes, high quality paper, etc.
❖ Antibiotics:
1. Many diseases of human and other animals have been controlled
due to antibiotics obtained from different types of bacteria and
fungi.
2. Antibiotics like penicillin, cephalosporins, monobactam, bacitracin,
erythromycin, gentamycin, neomycin, streptomycin, tetracycline,
vancomycin, etc. are used against various strains of gram positive
and gram negative bacteria.
3. Rifamycin is effective against tuberculosis.
❖ Microbes and Fuels:
1. Gaseous fuel- methane can be obtained by microbial anaerobic
decomposition of urban agricultural and industrial waste.
2. Ethanol, an alcohol is a clean (smokeless) fuel obtained during
fermentation of molasses by the yeast Saccharomyces.
3. Hydrogen gas is considered to be the fuel of future. Hydrogen gas is
released during bio-photolysis of water in which bacteria perform
the photoreduction.
❖ Bio-fuel :
1. Biofuel is important among the renewable source of good energy.
2. These fuels are available in solid (coal, dung, crop residue), liquid
(vegetable oils, alcohol), gaseous (gobar gas, coal gas) forms.

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3. These fuels are easily available and in plenty of quantity. These are
reliable fuels of the future.

❖ Land-filling sites
1. Compressed waste is dumped in the pit. It is covered with layers of
soil, saw dust, leafy waste and specific biochemicals.
2. Bioreactors are mixed at some places. Microbes present in soil and
other top layers decompose the waste.
3. Completely filled pit is sealed with soil slurry. Best quality compost
is formed after few days. Such land filling sites can be reused after
removal of compost.

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❖ Sewage Management:
1. Microbes which can decompose any compound as well as destroy
the pathogens of cholera, typhoid, etc. are mixed with sewage.
2. They release methane and CO2 by decomposition of the carbon
compounds present in sewage.
3. Phenol oxidizing bacteria decompose the xenobiotic chemicals
present in sewage.
4. The sludge that settles down in this process can again be used as
fertilizer. Water released after microbial treatment is
environmentally safe.
5. Microbes are used for bioremediation of environment polluted due
to sewage.

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❖ Clean Technology:
1. Microbes have natural ability of decomposing the manmade
chemicals. Hydrocarbons and other chemicals are transformed with
the help of these abilities.
2. Some microbes remove the sulphur from fuels.
3. Metals like copper, iron, uranium, zinc, etc. leach into environment
from low quality metalloids. These are converted into compounds
before leaching, with the help of thiobacilli and sulphobacilli.
4. Oil may prove fatal and toxic to aquatic organisms. It is not easy to
remove the oil layer from surface of water by mechanical method.
5. However, bacteria like Pseudomonas spp. and Alcanovorax
borkumensis have the ability to destroy the pyridines and other
chemicals. Hence, these bacteria are used to clear the oil spills.
6. These are called as hydrocarbonoclastic bacteria (HCB).

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7. HCB decompose the hydrocarbons and bring about the reaction of

carbon with oxygen. CO2 and water is formed in this process.
8. Plastic bottles are formed from the chemical substance PET
(Polyethylene Terephthalate Polyester).
9. Now a day, most of the urban garbage consists of plastic. It has been
observed that species like Vibrio, Ideonella sakaiensis can
decompose the PET.
10. Similarly, species of bacteria like Actinomycetes, Streptomyces,
Nocardia, Actinoplanes have ability of decomposing rubber from
garbage.
11. Sulphuric acid is present in the acid rain and materials coming out
of mines.
12. You know that erosion of metals present in statues, bridges and
buildings occurs due to it.
13. Sulphuric acid is source of energy for some species of bacteria like
Acidophillium spp. and Acidobacillus ferroxidens.
14. Hence, these bacteria can control the soil pollution occurring due to
acid rain.
15. Water soluble salts of uranium are present in the wastes produced
during electroplating and in effluent released in environment from
the atomic energy plant.
16. Geobacter convert these salts of uranium into insoluble salts and
thereby prevent those salts from mixing with ground water sources.

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8. Cell biology and biotechnology

❖ CYTOLOGY:
1. Study of structure, type, organelles of the cell is called CYTOLOGY.
2. Research institutes specially dedicated for research on cells are
established at Pune and Bengaluru, India.
3. National Center for Cell Science (http://www.nccs.res.in) at Pune
and ‘Instem’ (http://www.instem.res.in) at Bengaluru are involved
in valuable research.
❖ STEM CELLS:
1. Stem cells are present in the umbilical cord by which the fetus is
joined to the uterus of the mother.
2. These cells give rise to all other types of cells present in the body of
multicellular organisms.
3. Similarly, these cells play an important role in wound healing.
4. New organism is formed from the zygote that is formed by union of
male and female gamete. At the earliest stage of development,
organism is in the form of a mass of cells. All the cells in that mass
are almost alike. Those cells are called as stem cells.
5. During further development, these cells form any type of cell,
different types of tissues and perform different functions in the
body.

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6. This is the differentiation of stem cells. However, once the tissues

are formed, the cells in those tissues, at the most, can form same
types of cells only.
7. Stem cells are also present in the blastocyst stage of embryonic
development.
8. Stem cells are present in red bone marrow and adipose connective
tissue of adult human beings.
9. It has become possible to produce different types of tissues and the
degenerated part of any organ with the help of these stem cells.

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❖ Stem Cell Preservation

1. For the purpose of preservation, stem cell samples are carefully
collected from sources like cord blood, red bone marrow or embryo
(blastocyst) and are kept in small, sterile vials.
2. Those vials are kept in liquid nitrogen at -1350 C to -1900 C.

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❖ Stem cell research:

1. In biotechnology, stem cell research is a revolutionary event after
cloning. This technique has the potential of bringing about the
fundamental changes in the medical science.
2. Depending upon source, stem cells are of two types as embryonic
stem cells and adult stem cells.

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❖ Embryonic stem cells:

1. Division of the zygote starts and thereby it is converted into embryo.
2. Cells of embryo undergo repeated mitotic divisions.
3. Cell differentiation starts from 14th day of conception. Cells of
different organs like osteocytes (bone cells), hepatocytes (liver cells),
and neurons are formed due to differentiation.
4. Embryonic cells before differentiation are called as embryonic stem
cells.
5. 220 different types of cells in human body are formed from single
type cells i.e. embryonic stem cells.

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6. Thus, stem cells are primary type of undifferentiated cells with self-
multiplying ability and they are parent cells of all types of human
cells.
7. This property of stem cells is called as pluripotency.
8. It has been found that if these stem cells are collected well before the
beginning of differentiation on 14th day i.e. during 5th – 7th day and
cultured with certain biochemical stimulus in laboratory, as per the
stimulus, they can transform themselves into desired type of cells,
thereby tissues and finally into organs.

❖ Adult stem cells:

1. Stem cells can be obtained from the body of adult person too. There
are three main sources of stem cells in the body of adult persons.
2. Stem cells can be obtained from red bone marrow, adipose
connective tissue and blood. Besides, stem cells can be obtained
from cord blood immediate after birth.

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❖ Uses of Stem Cells:

1. Regenerative Therapy
A. Cell Therapy:
Stem cells are used to replace the dead cells in case of conditions like
diabetes, myocardial infarction, Alzheimer’s disease, Parkinson’s disease,
etc.

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B. To produce blood cells required in conditions like anaemia,

thalassemia, leukemia, etc.

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2. Organ Transplantation:
1) In case of failure of organs like kidney and liver, those can be
produced with the help of stem cells and transplanted availability of
donor is an important requirement in organ transplantation.
2) Each person has a pair of kidneys. As the process of excretion can
occur with the help of single kidney, person can donate another one.
3) Various factors like blood group, diseases, disorders, age, etc. of the
donor and recipient need to be paid attention during
transplantation.
4) Similarly, skin from certain parts of the body can also be donated
5) However, other organs cannot be donated during life time.
6) Organs like liver, heart, eyes can be donated after death only.
7) This has led to the emergence of concepts like posthumous (after
death) donation of body and organs.

❖ Organ and Body Donation:

1. Human bodies are disposed off after death as per traditional
customs. However due to progress in science, it has been realized
that many organs remain functional for certain period even after
death occurs under specific conditions.

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2. A liberal view behind the concept of organ and body donation is

that after death, our body should be useful to other needful persons
so that their miserable life would become comfortable.
3. Blinds can regain the vision. Life of many people can be rendered
comfortable by donation of organs like liver, kidneys, heart, heart
valves, skin, etc. Similarly, body can be made available for research
in medical studies.
❖ Biotechnology:
1. Various branches of science like cytology, biochemistry, molecular
biology, and genetic engineering are included in biotechnology.
2. There is considerable progress mainly in the field of agriculture and
pharmacy due to biotechnology.
3. In pharmacy, experiments for production of antibodies, vitamins,
and hormones like insulin have been successful. High-class varieties
of crops have been developed through the technique of tissue-
culture.
❖ Biotechnology includes following main areas:
1. Use of various abilities of microbes like yoghurt production from
milk and alcohol from molasses.
2. Use of productivity of the cells. Ex. – Production of antibiotics and
vaccines, etc. with the help of specific cells.
3. Use of bio-molecules like DNA and proteins in human welfare.
4. Development of plants, animals and products of desired quality by
gene manipulation. Production of human growth hormone with the
help of genetically modified bacteria.

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5. Use of genetic and non-genetic technique. Non-genetic

biotechnology involves use of either cell or tissue. Ex. Tissue culture,
production of hybrid seeds, etc.

❖ Benefits of Biotechnology :
1. It has become possible to increase the per hectare yield irrespective
of the limitations of crop-land area.
2. Expenses on disease control have minimized since development of
resistant varieties.
3. Due to development of fast fruit setting varieties, yield per annum
has been increased.
4. Development of stress resistant varieties which can withstand
variable temperature, water-stress, changing fertility of soil, etc. has
become possible.
{Development of Biotechnology in India: Government of India had
established the National Biotechnology Board in 1982. This board was
transformed into department of biotechnology under the ministry of
science and technology, in 1986. Various institutes in India are working
under the control of this department of biotechnology. It includes
National Institute of Immunology, National Facility for Animal Tissue
and Cell Culture, National Centre for Cell Science, National Brain

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Research Centre, Central Institute of Medicinal and Aromatic Plants.

There are facilities of higher education and research in these institutes
from where thousands of students have pursued Ph.D. degrees and are
contributing to the progress of country in the field of biotechnology.}
❖ Commercial Applications of Biotechnology:
1. Crop Biotechnology: Biotechnology is used in agricultural field to
improve yield and variety.
A. Hybrid Seeds: Genes of two different crops are recombined to form
hybrids of various crops. This is especially useful for fruits.

B. Genetically Modified Crops: Crops developed with desired

characters by integrating foreign gene with their genome are called
as genetically modified crops. High yielding varieties with
resistance to diseases, alkalinity, weeds other stresses like cold and
drought.
i. Bt Cotton: A gene had been isolated from the bacterium Bacillus
thuringiensis and integrated with the genome of cotton. Due to
this, the toxin which is fatal for bollworm was produced in leaves
and bolls of cotton. If bollworm feeds on leaves, the toxin destroys
its alimentary canal and the bollworm dies.

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ii. Bt Brinjal: BT Brinjal variety is developed by using the gene

isolated from Bacillus thuringiensis. This improved variety of
brinjal kills the pest in same way as the Bt cotton does.

iii. Golden Rice: A gene synthesizing the vitamin A (Beta carotene)

has been introduced in this variety of rice. As compared to the
normal variety, this variety which has been developed in 2005
contains 23 times more amount of beta carotene

iv. Herbicide tolerant plants: Weeds always affect the growth of

main crop. If herbicides are used to destroy the weeds, it affects

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the main crop too. Due to this, Herbicide tolerant plants varieties
of crops are being developed. Due to this, it has become possible
to selectively destroy the weeds.
v. Biofertilizers: Due to use of biofertilizers instead of chemical
fertilizers, nitrogen fixation and phosphate solubilization abilities
of the plants are improved. Mainly the bacteria like Rhizobium,
Azotobacter, Nostoc, Anabaena and plants like Azolla are used as
biofertilizers.

❖ Animal Husbandry: Two main methods as artificial insemination

and embryo transfer are used in animal husbandry. It helps to
improve both, the quantity and quality of animal products. Ex.
Milk, meat, wool, etc. Similarly, animals with more strength have
been developed for hard work.

artificial insemination

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Embryo transfer

❖ Human Health: Biotechnology helps to identify the role of gene, if

any, in disease of a person. Diagnosis of diabetes and heart diseases
has become possible even before the onset of symptoms, with the
help of biotechnology. Diagnosis of the diseases like AIDS, dengue
can be done within few minutes. Hence, treatment can be done at
the earliest. Various medicines are used for the treatment of
diseases. Ex. The hormone insulin is used in treatment of diabetes.
Earlier, insulin was being collected from the pancreas of horses.
However, nowadays, due to biotechnology, insulin can be prepared
with the help of bacteria. For this purpose, human insulin gene has
been inserted into the genome of bacteria. Various vaccines and
antibiotics are also produced in the same way.

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❖ Vaccines and Vaccination:

1. Vaccine is the ‘antigen’ containing material given to acquire either
permanent or temporary immunity against a specific pathogen or
disease.
2. Traditionally, vaccines were prepared with the help of pathogens.
Completely or partially killed pathogens were used as vaccines.

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3. However, due to this, there were chances of contracting the disease

in case of some persons.
4. Hence, as an alternative, scientists tried to artificially produce
vaccines with the help of biotechnology.
5. For this purpose, scientists produced the antigen in laboratory with
the help of gene isolated from the pathogen and used it as vaccine.
6. Thus, safer vaccines are being produced.
7. Now, proteins which act as antigen are injected in pure form instead
of injecting the killed or semi-killed pathogens.
8. These proteins keep the persons away from the diseases by keeping
the immune system active.
9. Thus, injecting the antigens is safest way in vaccination. Vaccines
produced with the help of biotechnology are more thermo-stable
and remain active for longer duration. Ex. Vaccines of polio,
hepatitis.

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A. Edible Vaccines:
1. Work on production of edible vaccines is in progress and presently,
potatoes are being produced with the help of biotechnology.
2. These potatoes are called as transgenic potatoes. These potatoes will
act against bacteria like Vibrio cholerae, Escherichia coli.
3. Consumption of these raw potatoes generates the immunity against
cholera and the disease caused due to E. coli.

B. Treatment:
Biotechnology is useful for production of hormones like insulin,
somatotropin and blood clotting factors.

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C. Interferon:
This is a group of small sized protein molecule used in treatment of viral
diseases. These are produced in blood. However, nowadays, with the
help of biotechnology, transgenic E. coli are used for production of
interferon.
D. Gene therapy:
Gene therapy to treat genetic disorders in somatic cells has become
possible due to biotechnology. Ex. Phenylketonuria (PKU) arises due to
genetic changes in hepatocytes (liver cells). It has become possible to treat
it with gene therapy. This method is called as somatic cell gene therapy.
All the cells except sperms and ova in the body are called as somatic cells.

E. Cloning:
Production of replica of any cell or organ or entire organism is called
cloning.
I. Reproductive cloning:
1. A clone can be produced by fusion of a nucleus of somatic cell with
the enucleated ovum of anybody.
2. Thus, there is no need of sperm to produce the new organism.

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❖ Dolly Sheep:
1. A sheep ‘Dolly’ was born in Scotland by cloning technique on 5th
July 1996.
2. Nucleus from the udder cell of sheep of ‘Finn Dorset’ variety had
been introduced into enucleated ovum of Scottish sheep.
3. Then, the ovum was allowed to develop in the uterus of Scottish
sheep and thereby the ‘Dolly’ had been born.
4. It was showing the characters as per the chromosomes in nucleus
and any character of Scottish sheep was not visible.

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II. Therapeutic cloning:

1. Stem cells can be derived from the cell formed in laboratory by the
union of somatic cell nucleus with the enucleated egg cell.
2. Various diseases can be treated with the help of these stem cells.
3. Similar to cells, genes can also be cloned and millions of copies of
same gene can be produced. Those can be used for gene therapy and
other purposes.
4. Controlling the inheritance of hereditary diseases, continuation of
generations, enhancing the specific tendency may become possible
due to cloning technique.
5. However, there is world-wide opposition to human cloning on
various issues.
❖ Industrial Products / White Biotechnology:
1) Various industrial chemicals can be produced through less
expensive processes.
2) Example: Alcohol production from sugar molasses with the help of
transgenic yeast.
❖ Environment and Biotechnology:
1) Microbial techniques are already in use for treatment on sewage and
solid waste. Sewage is rich in organic matter.
2) If such sewage is released in natural water bodies like rivers, the
organic matter in it gets oxidized with the help of dissolved oxygen.
3) Due to this, level of dissolved oxygen in water decreases, adversely
affecting the aquatic life.

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4) As a remedy on this, sewage should be released in to rivers only

after oxidation with the help of microbial technique.
5) Dolly (Clone), the Human Genome Project, one of the important
projects in the world.
6) Microbes are useful on large scale while production of compost by
treatment on solid organic waste material.
7) Bio-remediation, biopesticides, biofertilizers, biosensors, etc, are
some new concepts in biotechnological methods.

❖ Bioremediation:
1. Bioremediation means either absorption or destruction of toxic
chemicals and harmful pollutants with the help of plants and
microorganisms.
2. If plants are used for this purpose, it called as ‘phyto-remediation’.
Some examples of bioremediation are as follows-
i. The Pseudomonas bacteria are useful for cleaning the
hydrocarbon and oil pollutants from soil and water.
ii. The fern Pteris vitata can absorb the arsenic from the soil.
iii. Genetically modified variety of Indian mustard can absorb
selenium from soil. * Sunflower can absorb uranium and arsenic.
iv. The bacterium Deinococcus radiodurans is highly radiation
resistant organism.
v. It has been genetically modified and used to absorb the radiations
from radioactive debris.
vi. Grasses like alfalfa, clover and rye are used in phyto-remediation.

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❖ Food Biotechnology:
Food items like bread, cheese, wine, beer, yoghurt, vinegar are produced
with the help of microorganisms. These food items are probably the
oldest ones produced with the help of biotechnology.
❖ Cleaning of Oil Spillage in Oceans:
If oil spillage occurs, it adversely affects the marine life. Now, cleaning
the ocean without any harm to environment in cheaper way has become
possible with the help of oil-digesting and fast multiplying bacteria. India
born American citizen and scientist Dr. Anand Mohan Chakravarti had
for the first time suggested the use of such microbes. Naturally, the credit
for this discovery goes to him.
❖ DNA fingerprinting:
DNA sequence of each person is unique as that of the fingerprints. Due to
this, identity of any person can be established with the help of its
available DNA. This is called as DNA fingerprinting. It is mainly useful

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in forensic sciences. Identity of the criminal can be established with the

help of any part of its body found at the site of crime. Similarly, identity
of father of any child can be established. This research is performed in
Center for DNA fingerprinting and Diagnostics, Hyderabad.

Original DNA fingerprinting

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❖ Green revolution:
1. Almost all the countries, especially underdeveloped and developing
countries had been badly affected by the effects of poor quality and
quantity of food.
2. Various methods applied for harvesting maximum yield from
minimum land are collectively called as green revolution.
3. Improvised dwarf varieties of wheat and rice, proper use of
fertilizers and pesticides and water management has led to the
increased production of food grains and thereby large population
had been saved from hunger.
4. Dr. Norman Borlaug (USA) and Dr. M. S. Swaminathan (India) have
valuable contribution in green revolution.
5. Various research institutes and laboratories are engaged in
development of new varieties of various crops through research. Ex.
Indian Agricultural Research Institute (IARI), New Delhi, National
Citrus Research Institute, Nagpur and allied branches, Indian
Institute of Sciences, National Pomegranate Research Institute,
Solapur.
❖ White revolution:
1. Various parts of India were rich in milk and milk products.
However, those products were not sufficient to meet the needs of
far-flung regions.
2. Dr. Verghese Kurien proved through the cooperative movement and
use of biotechnology that Dairy cannot be allied but it will be a
mainstream business.

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3. He put the cooperative dairy movement of Anand, Gujarat at all

time high status.
4. While achieving the self-sufficiency in dairy business, various
experiments were performed for quality control, newer dairy
products and their preservation.

❖ Blue revolution:
1. Production of various useful aquatic organisms with the help of
water is called as blue revolution. Farm ponds and the fishes are
very common in East Asian countries.
2. However, people are not only thinking of cultivating the fishes and
shrimps but other aquatic plants and animals too.
3. Government of India has vowed to increase the production by
encouraging the people for pisciculture by launching the program
‘Nil-Kranti Mission-2016’ (NKM-16) 50% to 100% subsidies are
offered in this case.

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4. Marine and fresh water fishery is possible on large scale. Fresh

water fishes like rohu, catla and other fishery products like shrimp
and lobsters are being cultured on large scale

❖ Fertilizers:
1. Two types of fertilizers are used in agriculture.
2. One of those is organic manure and others are chemical fertilizers.
3. Water holding capacity of the soil improves with soil conservation
due to use of manures.
4. Upper layer of the soil essential in agriculture is formed due to
humus formation.
5. Various essential elements like N, P, K can be available to crops due
to earthworms and fungi.
6. In soil-less farming i.e. hydroponics, liquid chemical fertilizers are
used. However, there are more harmful effects of liberal use of
chemical fertilizers.
7. It includes decrease in fertility of soil.
❖ Insecticides:

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1. Though the natural immunity of plants can prevent the infections,

use of insecticides is not under control.
2. Irrespective of the natural friends of farmers like frogs and
insectivorous birds, pesticides are used on large scale for increase in
yield.
3. Pesticides are in fact a type of poison. This poison enters the food-
web through water and food and its bio-magnification occurs.
4. Various pesticides like DDT, malathion, chlorpyriphos, etc. have
been proved to be dangerous.
❖ Organic farming:
1. Chemical fertilizers and pesticides have been used on large scale.
These poisonous chemicals reached the human body through food
and water and their adverse harmful effects on human and
environment became apparent.
2. Various problems like soil fertility and pest infestation have become
serious. So as to overcome these problems, farmers are opting for
organic farming.
3. It includes complete ban on chemical fertilizers and pesticides and
use of local, sturdy varieties and thereby maintaining natural
balance.
❖ Apiculture:
1. You must have seen the bee hive.
2. Worst method of harvesting / collecting the honey from these hives
is driving away the bees by smoking the hive with burning torch
and then cutting the hive into pieces.

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3. This method causes the destruction of hive and large scale death of
bees.
4. However, it is easy to collect the honey without destroying the hive
and bees, if artificial bee boxes are used.

❖ Cultivation of Medicinal Plants:

1. India has been gifted with a great biodiversity.
2. We have a great tradition of ayurveda that cures the diseases with
the help of natural sources.
3. During earlier days, medicinal plants were collected from the forest.
However, due to depletion in forest area, medicinal plants are
becoming rare. Hence, medicinal plants are being cultivated.

Adhatoda vasica (Adulsa) Azadirachta Indica (Neem)

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❖ Fruit Processing:

1. We are daily using various products prepared from fruits.

2. All are consuming the products like chocolates, juices, jams and

jellies. All these products can be produced by processing on fruits.

3. Fruits are perishable agro-produce. It needs the processing in such a

way that it can be used throughout the year.

4. Fruit processing includes various methods ranging from storage in

cold storage to drying, salting, air tight packing, preparing murabba,

evaporating, etc.

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