Genetics

             Genetics is study of science of genes, heredity and variation in living organisms. Heredity is the cause of similarity between individuals and variation is the cause of differences between individuals. Genetics deals with transmission of characters from parents to offspring and the molecular structure and function of genes. The study of genes is done at three levels.

Transmission Genetics

Population Genetics    

Molecular Genetics 

TRANSMISSION GENETICS          

The two most fundamental questions in biology are – what is the nature of genetic material and how is it transmitted from parents to offspring? The fact that living things inherit traits from their parents has been used in prehistoric times to improve crop plants and animals through selective breeding. However modern genetics only began with the work of Gregor Mendel. His breeding experiments in pea plants revealed that hereditary characteristics are determined by discrete factors (genes) that are transmitted to the next generation.

THE LAWS OF INHERTANCE

          The study of science of genetics begins with the work of Gregor Mendel. He was a clergyman and a teacher. He performed his own experiment on garden pea. He restricted his attention to the single character and kept pedigree records for each plant. Mendel studied the nature of inheritance in plants and presented his work in 1885 in the paper “Experiments on Plant Hybridisation “. The importance of his work did not get noticed until 1890s, after his death. The advantages of garden pea (Pisum sativum) as experimental system were:

The characters were readily observable.

Plants were easy to grow and self fertilise before the flowers opened

Mendel worked with 14 pure breeding varieties and selected seven pairs of characters and propounded the following laws:

The law of dominance: Mendel stated that the hereditary characters are determined by pair of factors (genes) in an individual. In a monohy--brid cross all the plants in F₁ generation showed only one character   but in F₂ the other character appears. The character in F₁ generation is dominant and the one which expresses in F₂ generation is recessive e.g., the cross between two homozygous parents (P), one with two dominant alleles for tall plant (TT) and the other with two recessive alleles for dwarf plant (tt). The phenotype of the offspring in F₂ generation is dominant and the one which expresses in F₂ generation is recessive e.g., the cross between two homozygous parents (P), one with two dominant alleles for tall plant (TT) and the other with two recessive alleles for dwarf plant (tt).  The phenotype of the offspring in F₁ generation is tall plant but the genotype is Tt.  The F₁ heterozygote produces four kinds of gametes. When this plant self-pollinates, the T and t egg and sperm cells combine randomly to form ¼TT (tall), 2/4 Tt (tall) and ¼ tt (dwarf) offspring. The F2 generation has 1:2:1 genotypic ratio and 3:1 phenotypic radio.

Luminous bodies

Luminous bodies: Those objects which emit light by themselves are called luminous bodies.

e.g. - sun, stars, electric bulb etc.

Non- luminous bodies: those objects which do not emit light by themselves but are visible by the light falling on them emitted by self luminous bodies are called non-luminous bodies.

A material can be classified as:

(i)                  Transparent: the substances which allow most of the incident light to pass through them are called transparent e.g. glass, water.

(ii)                Translucent: The substances which allow a part of incident light to pass through them are called translucent bodies e.g. oiled paper.

(iii)               Opaque: The substances which do not allow the incident light to pass through them are called opaque bodies. E.g. mirror, metal, wood etc.

Reflection of light: Light moving in one medium when falls at the surface of another medium, part of light returns back to the same medium. This phenomenon of returning back of light in the first medium at the interface of two media is known as reflection of light.

Laws of reflection

(i)                  The incident ray, reflected ray and normal to the reflecting surface at the incident point all lie in the same plane.

(ii)                The angle of reflection is equal to the angle of incidence.

Reflection from plane mirror

(i)                  The image is virtual, laterally inverted.

(ii)                The size of image is equal to that of object.

(iii)               The distance of image from the mirror is equal to distance of object from the mirror.

(iv)              If an object moves towards (or away from) a plane mirror with speed v, relative to the object the image moves towards (or away) with a speed 2v.

(v)                If a plane mirror is rotated by an angle θ, keeping the incident ray fixed, the reflected ray is rotated by an angle 2θ.

(vi)              To see his full image in a plane mirror, a person requires a mirror of at least half of his height.

(vii)             If two plane mirrors are inclined to each other at an angle θ the number of images (n) of a point object formed are determined as follows:

(a)    If 360  /θ  is even integer, then n= 360 /θ = 1

(b)   If  360/ θ is odd integer,

Then n=360/ θ -1 for the object is symmetrically placed and

N = 360 /θ for the objects is not symmetrically placed.

(c)    If 360 /θ are a fraction then n is equal to integral part.

Range of different thermometers

Mercury Thermometer: from -30˚C to 350˚C

Constant volume gas thermometer: from -200˚C to 500˚C (with H₂), below -200˚C upto -268˚C (with He) above 1000˚C upto 1600˚C (with N₂ gas and bulb of glazed porcelain)

Platinum resistance thermometer: form -200˚C to 1200˚C

Thermocouple thermometer: form -200˚C to 1600˚C

Total Radiation Pyrometer

When a body is at high temperature, it glows brightly and the radiation emitted by the body is directly proportional to the fourth power of absolute temperature of the body. Radiation pyrometer measures the temperature of a body by measuring the radiation emitted by the body.

This thermometer is not put in contact with the body. But it cannot measure temperature below 800˚C because at low temperature emission of radiation is very small and cannot be detected. 

Specific Heat Capacity: Specific heat capacity of a material is the amount of heat required to raise the temperature of unit mass of substance through 1˚. Its SI unit is Joule/ gram˚C.

1 calorie / gram˚C = 4200 Joule / kg Kelvin.

Thermal Expansion

When a body is heated its length, surface area and volume increase. The increase in length , area and volume with the increase in temperature are measured in terms of coefficient of linear expansion or linear expansively (α) coefficient of superficial expansion or superficial expansively (β) and coefficient of cubical expansion or cubical expansively (γ).

Specific Heat Capacities of different materials (J/kg K)

Water                             4200

Ice                                  2100

Iron                                460

K. Oil                             210

Mercury                         140

Lead                               130    

Relation between α, β and γ.

α: β :γ =1:2:3                   or,    β=2   α and  γ =3α

Economic Impact of British Rule

Three stages of British Colonialism 

First phase- The Mercantile phase (1757-1813)

                   The East India Company used its political power to monopolize trade and dictate terms to traders of Bengal. 

                   Imposition of Inflated prices of goods id to buccaneering capitalism whereby wealth flowed out of barrel of the British trader’s gun. 

                   Revenues of Bengal were used to finance exports to England

. Second phase –The Industrial phases (1813-1858) 

                   India was exploited as a market for British goods.

                   Act of 1813 allowed one way trade for the British, as a result the Indian markets flooded with cheap and machine –made imports. Indian traders lost foreign as well as home market.

                   Indians were forced to export raw materials and import finished goods. 

                   Act of 1813 allowed one way trade for the British, as a result the Indian markets flooded with cheap and machine- made imports. Indian traders lost foreign as well as home market.  

                   Indians were forced to export raw materials and import finished goods.

                   Heavy import duty on Indian products to England to discourage them in the market.

Third phase- Financial phase (1860 onwards)

                   The British consolidated their position in India and made India a market for manufactures and a supplier of foodstuffs and raw materials.

                   Introduction of Railways (1853), Post and Telegraph (1853), banking System (Avadh Commercial Bank- 1881).

                   Heavy British investment in India and burden of public debt increases.

                   Industries came into existence (Tata Iron and Steel in 1907).

Geographical Discoveries

Ø A great development which marked the beginning of the modern age in Europe was a series of geographical discoveries.

Ø Helped by some remarkable inventions viz. the compass and astrolabe, daring sailors sailed from distant lands.

Ø They were financed by rulers and merchants.

Ø The main motivation behind these adventures was the lure of profits that trade with the east would bring.

Ø During 1288-93, Marco polo (1256 – 1326), Venetian traveler, travelled from Venice to china and Japan. He was the ‘first European to visit china’. From his travelogue the European learned about the all-round prosperity of the east.

Ø The first great steps in the exploration of the earth were taken by the sailors under the patronage of Portuguese and Spanish rulers.

Ø Prince Henry (1394 – 1460) the navigator of Portugal, encouraged sailors by making maps based on trips to the African coast.

Ø In 1487, Bartholomew, Diaz, reached the point which the Portuguese named Cape of Good Hope (the southern - most point of Africa).

Ø Vasco d agama followed this route and sailed on round the cape and reached Calicut in India in 1498.

Ø Italian sailor Columbus’ trip was financed by Spain from where he sailed in 1492. When he had reached d hand, he thought he had reached India; so he called the islands, the ‘Indies’; but it was America.

Ø The land discovered by Columbus was son to be called the ‘Americas’ after the name of a later Italian explorer, America Vespucci.

Ø Magellan, a Portuguese sailor, went beyond the lands that had stopped Columbus. He sailed went around the tip of South America, which is named after him – the straits of Magellan. He called the new ocean that the entered,’ the pacific’ because it seemed more quiet than the atlantic.magellan reached what is now called the Philippine island where he died. Magellan was the first to sail round the world.

Ø Other countries – England, France &Holland – also sent out their ships to join the race for  explorations. Francis drake fenland sailed round the world in 1577. Colonialism: colony means the country or territory settled by migrants from another country. Thus, the policy of having, colonies and keeping them dependent is called colonialism.

Ø Imperialism: the policy of extending a state’s rule over other terriotories and of incorporating such colonized into an empire is called imperialism.

GEOGRAPHICAL DISCOVERIES :

DISCOVERY	YEAR		DISCOVER (NATIONALITY)			SPONSERED BY
Cape of good  hope	1487		Bartholomew Diaz (Portuguese)			Portugal
America	1492		Christopher Columbus (Geneon, Italian)			Spain
Newfoundland	1947		John Cabot (Italian)			England
Sea – route of India via cape of good hope	1498		Vasco d agama (Portuguese)			Portugal
brazil	1500		Pedro ablates cabral (Portuguese)			Portugal
Strait of Magellan	1520		Magellan(Portuguese)			Spain
Island of Tasmania & new Zealand	1642		Tasman (Dutch)			Holland
Sandwich Island/Hawaiian island	1770		Captain James cook (British)			England
North pole	1909		Robert Peary (American)			USA
South pole	1911		Amundsen (Norwegian)			Nor  way

Important Articles of the constitution

                          Articles            subject

Part I             Art. 1-4            The Union and its territory.

Part II           Art 5-11                Citizenship

Part III            Fundamental Rights

Art. 12            Definition

Art. 13            Laws inconsistent with or in derogation of the fundamental rights

Right to Equality

Art. 14       Equality before law

Art. 15        prohibition of discrimination on grounds of religion race, caste, sex or place of birth

Art. 16          Equality   of opportunity in matters of public employment

Art .17           Abolition of untouchability

Art. 18            Abolition of titles

Rights to Freedom

Art. 19        Protection of certain rights regarding freedom of speech, etc.

Art. 20          protections in respect of conviction for offences

Art. 21          Protection of life and personal liberty

21A.              right to education

Art. 22          Protection against arrest and detention in certain cases 

Right against Exploitation

Art. 23            Prohibition of traffic in human beings and forced laour

Art .24             prohibition of employment of children in factories, etc.

.

Fundamental Duties

The Fundamental Duties are eleven in number, incorporated in Art. 51A [Part IVA], which has been incorporated by the 42^nd Amendment act, 1976.

Under this Article, it is the duty of every citizen of India:

1.       To abide by the Constitution and respect its ideals and institutions, the National Flag and the National Anthem;

2.       To cherish and follow the noble ideals which inspired our National struggle for freedom;

3.       To uphold and protect the sovereignty  unity and integrity of India;

4.       To defend the country;

5.       To promote harmony and the spirit of common brotherhood amongst all the people of India.

6.       To p value and preserve the rich heritage of our composite culture;

7.       To protect and improve the natural environment;

8.       To develop the scientific temper and spirit of inquiry;

9.       To safeguard public property;

10.   To strive towards excellence in all spheres of individual and collective activity.

11.   To provide opportunities for education to his child or ward as the case may be between the age of six and fourteen years.

Note: The 11^th Fundamental Duty was added by the 86^th Constitutional Amendment Act, 2002.

There is no provision in the Constitution for direct enforcement of any of the Fundamental Duties or for any sanction to prevent their violation.

Fundamental Rights

Fundamental Rights

Six Fundamental Rights have been provided by the Constitution:

1.       Right to equality

2.       Right to liberty

3.       Right against exploitation

4.       Right to freedom of religion

5.       Cultural and educational rights

6.       Right to constitutional remedy.

The Union and its territories

Article 1 lays –down that India, i.e. Bharat, shall be a Union of states The Territory of India shall consist of (i) the Territories of the States, (ii) the Union territories and (iii) any territories that may be acquired. 

Article 1 of the Constitution describes India as a Union of states not as a federation of states. Union of India is not the result of an agreement nor has any state the right to secede from it.

The Federation is called a Union of States, because it is indestructible 

The Union Territories are not included in the “Union of States”. Whereas the expression “Territory of India” includes the states, the Union Territories and such other territories as may be acquired by India.

The States and their territories are specified in the first Schedule to the Constitution. The Constitution empowers the Parliament for the admission or establishment of new States.

Citizenship

The constitution of Indian Provides for a single and uniform citizenship for whole of India.

Citizenship of India was granted to every person who domiciled in the territory of India at the commencement of the constitution and who was born in the territory of India or-

·         Either of whose parents was born in the territory of India or

·         Who had been ordinarily residing in the territory of India for not less than five years immediately preceding commencement of the Constitution?

Indian citizens have the following rights under the Constitution which aliens do not possess:

world war 2 summary

world war 2 summary timeline and important dates (Jan 30, 1933 to Nov 3, 1939 ) :

Jan 30, 1933 Hitler Becomes Chancellor

Adolf Hitler becomes Chancellor of Germany.

Oct 3, 1935 Mussolini Invades Ethiopia
Italy, under the leadership of Prime Minister Benito Mussolini, invades Ethiopia.

May 1, 1937 Neutrality Act
President Franklin D. Roosevelt signs the 1937 Neutrality Act, which bans travel on belligerent ships, forbids the arming of American merchant ships trading with belligerents, and issues an arms embargo with warring nations.

Jul 7, 1937 Japan Defeats China
The Japanese defeat Chinese forces in a clash near Peking, taking control of North China.

Sep 14, 1937 Roosevelt Limits Ships to Asia
President Franklin D. Roosevelt forbids U.S. ships from carrying arms to China or Japan.

world war 2 summary

world war 2 summary timeline and important dates Part I (Apr 1, 1940 to Dec 11, 1941 ) :

1940For Whom the Bell Tolls Published
American author Ernest Hemingway publishes For Whom the Bell Tolls, a novel about a young American in Spain who joins an antifascist guerrilla force in the Spanish Civil War.

Apr 1, 1940 Hitler Seizes Low Countries
Adolf Hitler takes neutral Denmark, Norway, Belgium, Holland, and Luxembourg.

Apr 1940 Germany Pummels France
German fighter planes and ground troops pummel France.

Apr 1940 Hitler Defeats France
Britain forces retreat from France and Adolf Hitler's armies defeat French forces.

May 1940 Allied Support Grows
The Committee to Defend America by Aiding the Allies is founded.

world war 2 summary

world war 2 summary timeline and important dates Part II (Jan 6, 1942 to Sep 2, 1945 ) :

Jan 6, 1942

Largest Budget in History

President Franklin D. Roosevelt delivers his State of the Union address in which he proposes a massive government spending budget, the largest in American history.

Oct 23, 1942North African Theatre

In the first major Allied offensive, British and U.S. armies attack Germany's Africa Korps on the Mediterranean chasing forces back toward Libya.

Nov 8, 1942US Troops Land In Africa

Under the leadership of General Dwight D. Eisenhower, U.S. troops land in Algiers, Oran, and Casablanca in North Africa.