12th botany neet school

Basic techniques of plant tissue culture

Basic techniques of plant tissue culture

Basic techniques of plant tissue culture

Techniques of plant tissue culture

Techniques of plant tissue culture are listed below:-

1. Culture vessels

The culture vessels used for plant tissue studies includes Erylenmayer flask (conical flask), petri plates and culture tubes (25 x 150mm).

2. Culture medium

The important media used for all purpose experiment are Murashige and Skoog medium (MS medium), Gamborg medium (B5 medium), White medium (W medium) and Nitsch medium.

The culture medium is closed with cotton plug/ or aluminium foil sheet. The pH of the medium is adjusted to 5.8 (acidic range).

3. Sterilization

Sterilization is the technique employed to get rid of the microbes such as bacteria and fungi in the culture medium and plant tissues.

So, it is important to sterilize the culture medium and plant tissue.

technique of tissue culture

The culture medium can be sterilised by keeping it in an autoclave and maintaining the temperature of 121’C for 15 minutes.

The plant tissue (inoculum) is to be surface sterilised.

Chemical sterilization

By treating the inoculum in any one of the chemical sterilizant such as Sodium hypochlorite, Calcium hypochlorite, Mercury chloride for 15 to 20 minutes followed by repeated washing in sterile water upto 3 to 5 times.

4. Inoculation

Transfer of explant (root, stem, leaf, etc.) on to a culture medium is called inoculation.

The inoculation is carried out under aseptic condition for which an apparatus called laminar air flow chamber is used.

Flamed and cooled forceps are used for transfer of plant materials to different culture media kept in glasswares.

5. Incubation

The culture medium with the inoculum is incubated at 26 + 20C with the light intensity at 2000 to 4000 lux (unit of intensity of light) and allowing photoperiod of 16 hour of light and 8 hours of darkness.

6. Induction of callus

Due to activity of auxins and cytokinins, the explant is induced to form callus.

The callus is an unorganized mass of undifferentiated tissue.

The mechanism of callus formation is that auxin induce cell elongation and cytokinin induces cell division as a result of which masses of cells are formed.

7. Morphogenesis

Formation of new organs from the callus under the influence of auxin and cytokinin is called morphogenesis.

Roots and shoots are differentiated from the callus.

Such embryos are called somatic embryos result in the formation of young plantlet.

There are two types of morphogenesis

a. Organogenesis

Formation of new organs such as shoot and root is known as organogenesis.

The development of shoot from the callus is called caulogenesis and formation of root is called rhizogenesis respectively.

b. Embryogenesis

Formation of embryos (ie. bipolar structure having shoot and root) from the callus is called embryogenesis.

These embryos arise from somatic callus tissue and are called somatic embryos or embryoids or somaclonal embryos.

8. Hardening

Exposing the plantlets to the natural environment in a stepwise manner is known as hardening.

Finally the plantlets are gradually transferred to the soil.

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Recombinant DNA technology

Gene transfer in plants, Cutting of DNA, Advantages of recombinant DNA

Transgenic plants – Herbicide resistance in transgenic plants

Practical application of genetic transformation

Plant tissue culture – origin and techniques


Status of tissue culture technology in India And application

Protoplast fusion and Practical applications

Single cell protein and its uses

12th botany neet school

Structure of DNA and Function of DNA

Structure of DNA

Structure of DNA

DNA and RNA are identified in the nucleus.

They are complex macro molecules and made up of millions of smaller units called nucleotides.

Hence, DNA is a macromolecular substance with double stranded polynucleotide.

Each nucleotide is made up of pentose sugar, a phosphate group and a nitrogenous base.

Ribose is the constituent sugar in RNA and Deoxyribose in DNA.

The nitrogenous bases are of two kinds – purines and pyrimidines.

Adenine and guanine are the purines and thymine and cytosine are pyrimidines.

The nitrogenous bases found in DNA are adenine, guanine, cytosine and thymine, whereas in RNA thymine is replaced by uracil.

The sub-unit containing only sugar and nitrogenous base is known as nucleoside.

A nucleoside combines with phosphate to form a nucleotide. Thus, four kinds of nucleotides are seen in DNA molecule.

They are adenine nucleotide, guanine nucleotide, thymine nucleotide and cytosine nucleotide.

Hence, nucleotides are building blocks of DNA.

DNA – Structure of DNA 
Structure of DNA 

In 1953, James Watson and Francis Crick proposed double helix DNA model on the basis of x-ray diffraction studies with photographs of DNA taken by Wilkins and Franklin.

DNA is a double stranded structure in which the two strands are coiled around each other forming a double helix.

The DNA duplex is “coil of life”.

There are two grooves found in DNA molecule namely major and minor grooves.

The backbone of the helix is formed of sugar and phosphate molecule.

The nitrogenous bases are attached to sugar molecules.

The two nucleotide strands are held together by unstable hydrogen bonds.

Erwin Chargaff in 1949 showed that

(i) The bases pair in specific manner. Adenine always pairs with thymine and guanine pairs with cytosine.

(ii) Total amount of purine nucleotides is always equal to the total amount of pyrimidine nucleotides i.e.[A] + [G] = [T] + [C].

(iii) The proportion of adenine is equal to thymine and so also of guanine is equal to cytosine.

But the [A] + [T] need not necessarily be equal to [G] + [C].

These empirical rules regarding the composition of bases in DNA is collectively known as Chargaff’s law or Base pair rules.

There are two hydrogen bonds between adenine and thymine (A= T) and there are three hydrogen bonds between guanine and cytosine (G≡C) pairing.

The two strand run antiparallely in opposite directions ie. they run in opposite direction 5’ to 3’ end and 3’ to 5’ end.

The two strands are interwined in clockwise direction. The width of DNA molecule is 20 A.

The strand completes a turn every 34 A along its length. There are ten nucleotides per turn.

The internucleotide distance is 3.4 A. Watson and Crick model of DNA is called B-form DNA.

The chains in B-form DNA are in right handed orientation.

Functions of DNA

It controls all the biochemical activities of the cell.

They carries genetic information from one generation to other. It controls protein synthesis and synthesize RNAs.

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Types of chromosomes with special types

Gene and genome

Linkage and mechanism of linkage

Crossing over, gene mapping and recombination of chromosome

Mutation and classification of mutation

Mutagenic agents and its significance

Structural Chromosomal aberrations

Numerical chromosomal aberrations

Role of DNA 


Replication of DNA

Structure of RNA and Types of RNA

12th botany neet school

Botanical description of Hibiscus rosa sinensis

Botanical description of Hibiscus rosa sinensis

Hibiscus rosa sinensis

Botanical description of Hibiscus rosa sinensis

Hibiscus rosa sinensis General Characters


Perennial shrub.


Tap root system.


Aerial, erect, cylindrical, woody and branched.


Simple, Alternate, petiolate, stipulate, serrate, glabrous, apex acuminate with multicostate reticulate venation.


Solitary cyme and axillary.


Pedicel jointed, bracteate, bracteolate, bisexual, large, showy, pentamerous, dichlamydeous, actinomorphic, complete and hypogynous and mucilage is present in floral parts.


5 to 8 bracteoles outer to the calyx. They are green and free.


Sepals 5, green, gamosepalous showing valvate aestivation and odd sepal is posterior in position.


Petals 5, variously coloured, polypetalous but fused at the base and showing twisted aestivation.


Numerous stamens, monadelphous, filaments are fused to form a staminal tube around the style.

Staminal tube is red. Anthers are monothecous, reniform, yellow, transversely attached to the filament, dehisce transversely and extrorse.

Floral diagram

Hibiscus rosa sinensis


Ovary superior, pentacarpellary and syncarpous.

Ovary pentalocular with many ovules per locule on axile placentation.

Style simple, long, slender and passes through the staminal tube. Stigma 5, capitate and coloured.

Mostly abortive.


1. Fibre plants

Gossypium barbadense (Egyptian cotton), G. hirsutum (American cotton), G. herbaceum (Cotton) and several other species of Gossypium yield cotton fibres of commercial value.

The fibres are obtained from the surface of seeds. Hibiscus cannabinus (Deccan hemp) yields bast fibres which are used for making ropes.

2. Food plants

The tender fruit of Abelmoschus esculentus (lady’s finger) is used as vegetable.

The leaves and sepals of Hibiscus sabdariffa (A kind of ‘pulichai’) are used for making pickles, jam and jelly.

A delicious ‘chutney’ is prepared from the leaves and sepals of H. cannabinus (Pulichai keerai) and H. sabdariffa.

3. Timber Plants

Timber obtained from Thespesia populnea (portia tree) is useful for making boat, furniture and agricultural implements.

4. Medicinal plants

Root and leaves of Abutilon indicum (Thuthi) and Malva sylvestris are used against fever.

Roots of Malva sylvestris and Althaea rosea are used for treating whooping cough and dysentery respectively.

5. Ornamental plants

Althaea rosea (Hollyhock), Hibiscus rosa sinensis (Shoe flower) H schizopetalus (A kind of shoe flower with dissected petals) are grown in gardens.

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  1. Write a note on androecium of Hibiscus rosa sinensis.
  2. Describe the gynoecium of Hibiscus rosa sinensis.
  3. Mention the binomial of any three medicinal plants of
  4. Draw the floral diagram and write the floral formula of Hibiscus rosa sinensis.
  5. What is epicalyx? It is present in Abutilon indicum?
  6. Give a detailed account on economic importance of Malvaceae.
  7. Describe Hibiscus rosa-sinensis in botanical terms.

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Bentham and Hooker’s classification of plants

Dicot Families – MALVACEAE


Solanaceae – Datura metal and Economic importance

Euphorbiaceae and Ricinus communis and its Economic importance

Musaceae – Musa paradisiaca and its Economic Importance

10th Social Science History school

Capture of Power Achievement of hitler Aggressive Policy

Capture of Power

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Under the inspiring leadership of Hitler, the Nazi Party grew in power and number. In the election of 1932′ the Nazi party became the 2″d largest

group in the German Parliament (Reichstag-LowerHouse). ln 1933, the Nazists became the largest party in the German  Parliament, and Hitler became the  Chancellor and Hindenburg as President.

On the death of President Hindenburg in August 1934, Hitler made himself President and Chancellor.

He abolished the Weimar Republic and proclaimed Third Reich (Empire) with himself as dictator. Thus Hitler became the Fuhrer (Leader) of Germany. Hitler declared,

‘One People’

‘One State’

‘One Leader’

Achievement of hitler

The Nazis glorified the German State, Hitler boasted about the superiority of the Nordic race which stood for the rise of all the great culture and had utmost contempt for the Semitic Jews.

He wanted to maintain a German race with Nordic elements. He ordered the Jews to be persecuted.

Hitler believed in action, force and terrorism. There was no scope for public liberty. Nazism was an one party state and all other parties were outlawed.

Parliamentary institutions were suppressed and the fundamental rights of the people were denied.

He gave a new status and position to Germany.   Federal   Nature   of   the

Constitution was set aside. He created a strong, unified and highly centralized despotic state.

In the economic field, his work was commendable. The  war  had completely shattered the economic system of Germany. But Hitler put the country on the path of prosperity.

He replaced Trade Unions by the Labour Front which consisted of the representatives from  both  the employers and the employees. It looked after the general welfare of the workers.

Strikes and lock-outs were outlawed. He made Germany economically  self-sufficient in food grains, raw  materials  and  industrial goods.

More lands were brought under cultivation, Scientific methods were introduced.

Defence industries and Rearmament Programme of Hitler gave employment to many people.

Many schools were opened and illiteracy was eradicated. The children were trained in the Nazi culture.

Only Nazi men were appointed as teachers and only Nazi books prescribed for study.

Women occupied a degraded place and they were treated as child­ bearing machines. All kinds of social organizations were dissolved.

Hitler’s Aggressive Policy

Hitler followed a forward and aggressive foreign policy. His aggressive imperialist policy brought danger and destruction to his country and sufferings and difficulties to the people all over the world.

Hitler introduced conscription and rearmed Germany. He followed the policy of aggression and conquered territories to accommodate the  growing population and to accumulate resources.

He pulled Germany out of the  League  of  Nations  in  1933.  In 1936, he reoccupied Rhine land, the demilitarized zone  and  violated the Locarno treaty of 1925.

In November 1937 Hitler formed an Alliance with Italy and Japan known as Rome­ Berlin-TokyoAxis.

He annexed Austria in 1938. When he wanted to annexe Sudetenland from Czechoslovakia, an agreement was signed between Germany and Neville chamberlain, the then Prime Minister of Great Britain at Munich in 1938.

By the Munich pact Germany was allowed to annex the Sudetenland but not to conquer any more territories.

In 1939, Hitler violated the Munich agreement by annexing the whole of Czechoslovakia. It greatly alarmed Britain and France.

Hitler demanded  the  right to construct a military road connecting East Prussia with Germany through Poland and also the surrender of Danzig.

Hitler sparked the Second World War by declaring war on Poland on 1st Sept. 1939 when Poland refused to consent to the demands of Hitler.

In 1941, Hitler invaded Russia, breaking the Non -aggression pact with Stalin. This invasion failed to achieve the quick triumph that Hitler wanted.

In 1945 the allied forces entered Berlin, Hitler having lost all hopes of success committed suicide in his bunker.

After the death of Hitler, the Second World War came to an end and the Nazi party was also fizzled away.

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10th Social Science History school

Nazism in Germany ( A.D.1933 – A.D.1945)

Nazism in Germany ( A.D.1933 – A.D.1945)

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Germany, a powerful empire in the early years of the 20th century, fought the First World War (1914-1918) against  the  Allies  (England, France and Russia).

Germany made initial gains    by   occupying  France  and Belgium. However the Allies strengthened by the US entry in 1917, defeated Germany and the Central Powers in November 1918.

Defeat of Germany

The defeat of Imperial Germany and the abdication of the Emperor William II gave an opportunity to parliamentary parties to  recast German polity.

A National Assembly met at Weimar and established a democratic   constitution  with federal structure.

This  republic, however, was not received well by its own people.

The  Peace  Treaty  at  Versailles with the Allies was a harsh and humiliating one.

Germany lost its overseas colonies and one tenth of its population. The  Allied Powers demilitarized Germany to weaken its power.

Germany was forced to pay war compensation amounting to £6 billion.

The allied armies also occupied the resources rich Rhine land. Many Germans held the new Weimar Republic responsible for  not   only the defeat in the war but also the disgrace at Versailles.

The 1929   Great Economic Depression also affected the economy of Germany.

The Germans were expecting a great leader to save Germany from this agony.

Adolf Hltler (1889-1945)

Adolf Hitler was born in 1889 in Austria.  His father was a custom officer. He lost his parents very early. He went to Vienna for job.

At this juncture there emerged a great leader, Adolf Hitler.

He was a painter for sometime. He joined the army during the First World War and fought bravely for which he was awarded the Iron Cross.

After the war,he did not get any job and he took to politics. He organized  a group  of men called the National Socialists  in 1919, which became Nazist Party.

He gave   his   group   a   programme,   a symbol and uniform. The followers of Hitler were called ‘Brown Shirts’ and he was called  ‘Fuhrer’ (leader).

His party  emblem  was  Swastika() His secret police was Gestapo.

Hitler began his political career as an agitator. In 1923, he made an attempt to capture power.

It was known as  Hall Revolution’. But he failed and was arrested for high treason and sentenced  to  5 years  imprisonment.

While he was in prison he wrote a book called ‘Mein Kampf (My Struggle), which became the bible of Nazis. Soon he was released.

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10th Social Science History school

Achievements of italy under mussolini

Achievements of Italy under Mussolini

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Mussolini was a great leader. He wanted to make Italy a powerful nation. So, he adopted various  methods. Mussolini established peace and order and he provided a stable government.

Mussolini brought order and discipline in the industrial field. The “Charter of Labour” issued by him provided great relief to workers. Industries were freed from strikes.

Mussolini took several measures to increase production. Marshes were drained. Canals were dug. Reclamation projects  were launched. Hydroelectric schemes were undertaken.

Railways and other means of transportation were improved. A fair degree of self sufficiency was achieved.

As a realistic administrator, Mussolini patched up with the Pope. A conflict that had been going on for nearly 60 years between the Papacy and the Italian government came to an end by the Latern Treaty of 1929, signed  between the  Pope and Mussolini.

By this treaty Mussolini recognized the papacy of the Pope in the Vatican city and in turn the Pope recognised the sovereignty of the king in Rome.

The reconciliation with the Pope was a great victory and it increased the power and prestige of Mussolini.

Aggressive foreign policy that ends In disaster

Mussolini began to follow the vigorous and forward foreign policy.He was determined to raise the prestige of Italy in the eyes of the other powers of the World.

Mussolini’s slogan before the nation was altaly must expand or perish”. In 1936, he annexed Ethiopia.

He left the League of Nations in 1937. He captured Albania in 1939. Mussolini made common cause with Hitler, another war monger.

He joined the Rome-Berlin-Tokyo axis. The Second World War (1939-45) brought disaster to Italy. In 1941, Italy lost its territories in Africa. Mussolini  failed to cope up with the financial burden of the war.

The Allied forces heavily bombarded Sicily and landed in the island in 1943.

Mussolini was shot dead by his own country men in 1945. After his fall, Italy became a Republic, Fascism died out along with the death of its founder, Mussolini.

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10th Social Science History school

Mussolini Benito(1883 -1945) Saizuro of Power Fascist Party

Mussolini Benito (1883 -1945)

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Benito Amilcare Andrea Mussolini was born on July 29,1883 at Romagna in East-Central Italy. His father was a blacksmith and  mother was  a elementary schoolteacher.

Mussolini graduated in 1902 and became a schoolteacher. He gave up that post and came to Switzerland.

He came into contact with Lenin and learned his ideology. He became an editor of Italian socialist paper in Austria.

He was expelled from Austria and returned to Italy. He edited a socialist paper called Avanti, the official voice of Italian Socialism.

During the first World War, he gave up his policy and joined the military.After the war he

gathered round him a band of young enthusiasts who came to be known as Fascists. With the help of the fascists, he organised the National Fascist Party in November 1921.

Saizuro of Power by the Fascists

On October 30, 1922,the Fascists organized a march to Rome and showed their strength. The government surrendered.

The emperor Victor Emanuel  II  invited Mussolini to form the Government. Thus the Fascist revolution became a spectacular success as the Fascists seized power without blood shed.

But the after math of revolution was marked by suppression, murder and exile. Fascist dictatorship under Mussolini came into existence.

He remained power from 1922 to 1945.

Fascist Party

The followers of Mussolini were called Black Shirts. He was called by his  followers  as  uouce”. His  secret police was known as OVRA (Voluntary Ogranisation for the Repression of anti-Fascists)

Alms of Fascism

‘Exaltation of the State Protection of Private property and Spirited Foreign Policy’

Motto of Fascism

‘Everything within the state Nothing against the state Nothing outside the state’

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10th Social Science History school

Fascism in ltaly (A.D.1922- A.D.1945)

Fascism in ltaly (A.D.1922- A.D.1945)

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The  term  Fascism is  derived from the Latin word ‘Fasces’ means  a bundle or group. Mussolini of Italy, who is associated with Fascism, organized in the beginning groups of young persons or gangs called the ‘fasces’,to create terror among the people who were considered enemies of the nation.

Fascism rests on four pillars of charismatic leadership, single party rule under a dictator, terror and economic control.

Mussolini believed in the efficacy of  these slogans and their accompanying action:·Believe,Obey, Fight and The More Force,The More Honour.

Reasons for the emergence of Fascism

The prevailing economic, social and political conditions were very favourable to the rise of fascismin Italy.

Economic crisis

Italy faced with a great economic crisis on account of the huge expenditure incurred on the war. The national debt increased manifold. There was social unrest and economic distress in the country, the prices of essential goods shot up. Cost of living rose very high. Socialism gathered new strength.

There was great dismay and frustration after the Treaty of Paris. Although a victor and constitute of the Allies, Italy did not gain substantially from thespoilsof war.Italy won the war but lost its peace.

Disruptive activities of the socialists

On account of the revolutionary ideas of the socialist, unrest had spread in the country.

Need for a charismatic leader

The situation demanded a bold leadership and the same was supplied by the fascist leader Mussolini.

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10th Social Science History school

Franklin D Roosevelt, Effects of Economic Depression

Franklin D Roosevelt

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  • The policy formulated to overcome depression by Franklin D Roosevelt is known as New  Deal.  It  Includes Relief,Recovery and Reforms
  • The  Tennessee Valley Authority was established for the promotion of construction of dams, power plants, navigation projects, flood control projects, soil conservation, and reforestation programmes.
  • The  Federal    Emergency Relief Administration (FERA) was set up to provide with 500 million dollars to be given to the state and local governments.
  • Federal Reserve Bank was set up to provide loans to banking institutions and industries.
  • The Security Exchange Act 1934, issued license to stock exchange.
  • The National Industrial Recovery Act (NIRA) was passed to reform the conditions of the workers by raising wages and lowering their working hours.
  • The  Agricultural  Adjustment  Act (AAA) was passed to provide compensation to farmers who curtailed agricultural production there by to raise prices.


  • Despite few limitations, the New Deal strengthened the American economy.
  • It restored confidence among the people.
  • It laid a firm foundation for industrial prosperity and led to increased production.

Many ideas of the new deal like,

  1. Collective bargaining between the employee and the workers.
  2. Regulation of stock exchange
  3. Restriction on hours of work are now accepted as part of the American pattern of life. New deal has become synonyms with reforms through out the world. By 1940 there was normal economic activities in the USA.

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10th Social Science History school

World Between The Two World  Wars (A.D.1919·A.D.1939) Economic Depression

World Between The Two World  Wars (A.D.1919·A.D.1939) Economic Depression

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The economic depression in late 1929 was one of the most important events of the world between the two wars. It is called ‘Great’as it adversely affected almost all the great countries of the world except USSR. The Great Depression  which  began  in USA, extremely affected the European countries


The main cause of the depression was the collapse of American share market. The share market collapse was due to speculation on borrowed money.

In 1929 Herbert Hoover became the President of America. During his period the share market reached its zenith. Share market was the greatest craze in America. People from all walks of life bought shares not for the dividend but for resale value. They wanted to become rich quickly

“The Great Depression..began on Oct 24, 1929 with the fall in the prices of shares. It created panic and people began to sell their shares speedily which led to a further fall. This was followed by the failure of banks which led to the non availability of credit which affected industrial growth and agricultural produce.

Remedial measures of the American President Hoover

In 1932, Hoover, the American president adopted many remedial measures. He  set up  the Reconstruction  Finance  Corporation to lend money to banks and industries, but the people lost faith on Hoover.

When the Presidential election came in 1932. Franklin D. Roosevelt, commonly known as FOR became the President of U.S.A. In his election manifesto he  said ·1 pledge  you, I pledge, myself to a New Deal for the Americans”. He assumed office on March 4, 1933.

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