Category: Maharashtra State Board Notes

By going through these Maharashtra State Board Secretarial Practice 12th Commerce Notes Chapter 3 Issue of Shares students can recall all the concepts quickly.

Maharashtra State Board Class 12 Secretarial Practice Notes Chapter 3 Issue of Shares

→ A joint-stock company can raise its capital by issuing shares, debentures, inviting public deposits, taking loans etc.

→ Share Capital refers to the capital made up out of equity shares and preference shares.

Share Capital can be classified as –

• Authorised or Nominal or Registered Capital
• Issued and Unissued Capital
• Subscribed and Unsubscribed Capital
• Called up and uncalled Capital and Reserve Capital
• Paid up Capital and Calls in Arrears

Company can raise capital by selling shares in the market. Generally it issues –

• Equity shares
• Preference shares.

A company can use the following methods for issues of shares –

• Public Issue
• Fixed price issue method
• book building method
• Initial public offer
• Further public offer
• Rights issue
• Bonus issue
• Employee stock option scheme
• Employee stock purchase scheme
• Stock appreciation rights scheme
• Sweat equity shares
• Private placement

Preferential allotment-

Allotment of Shares:
The Supreme Court has defined allotment as “the appropriation out of the previously unappropriated capital of the company of a certain number of shares to a person.
Thus allotment of shares means allotting shares to an applicant based on the application submitted.

Share Certificate:
It is a registered document issued by a company which is an evidence of ownership of specified number of shares of the company. Share certificate should be issued by the company within two months.

Calls on shares:
Besides the application money and allotment money, if a company demands the balance unpaid amount on shares it is called as calls on shares. It is unpaid money demanded by the company.

Forfeiture of Shares:
If a shareholder fails to pay calls on shares within a certain period, the Board of Directors can forfeit the ownership of a member which is called forfeiture of shares. It is a forceful act by the company. Here membership is terminated by the company.

Surrender of Shares:
Voluntary return of shares by the member to the company for cancellation of shares is called surrender of shares.

Transfer of shares:
Transfer of shares means voluntary transfer of shares by a member of a company in favour of another person against consideration. It is a voluntary activity.

Transmission of shares:
When the shares of a member is automatically transferred to the nominee or legal heir on the death, insolvency or insanity of a member, it is called transmission of shares. It is performed by operation of law.

By going through these Maharashtra State Board Secretarial Practice 12th Commerce Notes Chapter 2 Sources of Corporate Finance students can recall all the concepts quickly.

Maharashtra State Board Class 12 Secretarial Practice Notes Chapter 2 Sources of Corporate Finance

→ No business activity can ever be pursued without financial support.

→ Finance is necessary throughout the activities of promotion, organization, and regular operations of the business.

→ The finance needed by a business organization is termed as ‘Capital’

→ Capital formation is a process of collection of capital from various sources according to the financial plan of the company.

→ The various sources of finance can be divided into owned capital and borrowed capital which may be external or internal.

→ When capital is made available from within the organization, it is an internal source of financing.

→ When capital is raised from outsiders, it is an external source of financing.

→ Owned capital is regarded as permanent capital and borrowed capital is regarded as the temporary capital.

→ The various requirements of finance can be divided into short term (maximum one year) and long term (more than a year maybe 5,10,15 years).

→ There are various methods of raising finance namely shares, debentures, bonds, retained earnings/profits, public deposits, trade credit, bank credit, ADR (American Deposit Receipts), and GDR (Global Depository Receipts)

→ A share is a small unit of the share capital of a company.

→ They may be issued at par, premium, or discount and redeemed at par or premium.

→ Equity shares do not enjoy a preference for dividends and do not have priority for payment of capital at the time of winding up of a company.

→ Equity shareholders are risk-takers and hence they are the real owners of the company.

→ Preference shares have prior right to receive a fixed rate of dividend and return of capital in the event of winding up of the company

→ Preference shareholders are cautious investors.

→ They neither take part in management nor attend the meetings and vote on resolutions.

→ They can have class meetings if their rights are to be altered or have not received dividends for more than two consecutive years.

→ The debt acknowledged by a company by issuing a debenture certificate is called a debenture.

→ Debenture holders are creditors of the company.

→ They get fixed interest as a return on their investment.

→ A bond is an instrument issued by the government or business as evidence of debt.

→ Bondholders are creditors of the company.

→ They get fixed interest as returns on their investment regularly or as per terms agreed.

→ Retained earnings is the sum total of accumulated profit that is re-invested in the business.

→ It is a cost-effective method of raising funds and is also known as self-financing/ploughing back of profits/
capitalization of Reserves.

→ A public deposit is a collateral-free loan accepted by public companies for a short period of time ranging from 6
months to 36 months.

→ The company can raise loans from banks in the form of overdraft, cash credit, cash loans discounting of bills. etc.

→ Financial institutions provide financial aid and assistance to companies.

→ Trade credit is a credit extended by manufacturers and suppliers to follow businessmen for 15 days to a
month.

→ Discount is made available if payments are made early.

→ A Bill of exchange is a trade bill that is accepted by the bank and cash is advanced as a loan against it.

→ ADR (American Depository Receipt) and GDR ( Global Depository Receipt) are depository receipts through
which Indian Companies raise equity capital in international markets.

By going through these Maharashtra State Board Class 11 Political Science Notes Chapter 2 Liberty and Rights students can recall all the concepts quickly.

Maharashtra State Board Class 11 Political Science Notes Chapter 2 Liberty and Rights

Introduction:
Political concepts involve an analytical study of ideas that are central to political thought. In this chapter, we will examine the political concepts of Liberty and Rights. These deal with the status of the individual in society.

We will study the nature of what the concept of liberty should include i.e., views of thinkers like Hobbes, Locke. Rousseau, Mill, Bentham, classification, etc. This chapter also includes the study of rights, its classification, etc.

Meaning And Nature Of Liberty:
The term liberty is derived from the Latin word ‘liber’ which means ‘free’. Thus liberty means freedom. People are said to have liberty when the rights and duties of the citizens in a democracy are secured by the State. Liberty is an essential feature of a democracy.

Liberty has been explained in different ways such as an absence of restraints, freedom of choice, and availability of favourable conditions towards the attainment of happiness. It is also understood as self-rule i.e., freedom from foreign rule.

Views Of Different Thinkers About Liberty:
Thomas Hobbes: He explained liberty as the freedom that an individual has to act without restraint.

John Locke: He explained liberty within the context of morality. Liberty is a natural right of an individual which should be enjoyed rationally. Locke’s concept of liberty focuses on the absence of restraint and the freedom of choice.

Jean Jacques Rousseau: He looked at liberty from a collective perspective. His concept of liberty frees the individual from a class-based system and inequality. He did not consider liberty as a natural right. Rousseau stressed freedom of choice and the availability of favourable conditions in the concept of liberty.

Harold Laski: He explained liberty as the eager maintenance of that atmosphere in which men have the opportunity to be their best selves.

Jeremy Bentham: He looked at liberty from the perspective of attainment of happiness i.e., the principle of ‘greatest happiness of the greatest number’.

John Stuart Mill: He supported individual liberty and opposed unrestrained controls by the state.

Indian Concept Of Liberty:
Traditionally, in India, liberty is a spiritual idea signifying ‘salvation or emancipation from the cycle of birth and rebirth’. However, in modern times, liberty is understood as liberation from social constraints.

In British India, the concept of liberty was accepted as –

• Laws made by the British for the protection of individual rights e.g. law for the abolition of sati.
• Views of great reformers like Mahatma Phule, Dr Ambedkar. They believed liberty means freedom from caste inequality as well as from social constraints i.e., the liberation of lower castes from the domination of the upper castes.
• Mahatma Gandhi accepted the concept of Swaraj as liberty. This was a comprehensive concept that included freedom from British rule and western cultural domination. It gave more importance to self-governance, self-discipline and human values.

Two Concepts Of Liberty:
Isaiah Berlin discussed about Negative and Positive liberty in his famous essay, ‘Two concepts of Liberty’ Positive liberty emerged from modern liberalism while negative liberty emerged from Classical and Neoclassical liberalism. The core values of liberalism are individualism, rationalism, tolerance and justice. Positive liberty was advocated by Rousseau and Marcuse.

They advocated a correlation between liberty, equality, justice, and collective interest. Rousseau explained that the State is a sovereign power that represents the ‘General Will’. Hence, he supported the idea of state control over the individual. Marcuse advocated collective control as essential in community life.

Negative liberty opposes all restraints on liberty, especially by the State. It was advocated by Jeremy Bentham, John Stuart Mill, and others.

Rights:
Rights are those social conditions that are necessary for the development of our personality. Laski defines rights as ‘those conditions of social life without which no man can seek, in general, to be himself at his best.

Natural Rights – These rights are universal in character e.g., the right to life and liberty.

Moral Rights – These rights are based on the conscience of the person and of the community e.g., respect for elders.

Legal Rights – These rights are granted by the State and are codified in law.
These rights are not universal. Legal rights maybe

• Civil rights: related to the person and property of the individuals e.g., right to liberty, equality, property,
• Political rights: are available only to citizens in a democratic state and aim to encourage active political participation e.g., the right to vote, to contest elections.

Human Rights:
Meaning: Each person is entitled to certain basic, natural rights, simply by virtue of being a human being. Human rights are inalienable, universal, dynamic, related to the concept of justice and are necessary to uphold human dignity. Human rights include the right to life.

The General Assembly of the U.N.O. adopted the Universal Declaration of Human Rights (U.D.H.R.) on 10th December 1948. The U.D.H.R. combines the ideals of liberty, equality, justice and fraternity with natural and civil rights.

There are instances of human rights violations in many countries of the world due to poverty, malnutrition, discrimination and deprivation. Underprivileged sections of society, women, children are most vulnerable where violations of rights are concerned.

Part III of the Indian Constitution enumerates the Fundamental Rights of citizens. These include the Right to equality, Right to freedom, Right against exploitation, Right to freedom of religion, Cultural and educational rights and Right to constitutional remedies.

The judiciary has interpreted the meaning of rights and liberty in various judgements, e.g., in the Francis Coralie Mullin vs Union Territory of Delhi case (1981), the Supreme court gave a comprehensive meaning of liberty. The right to life meant the right to live with dignity. In the K. S. Puttaswamy vs Union of India case (2017), the Supreme Court declared right to privacy as a fundamental right.

By going through these Maharashtra State Board 12th Science Chemistry Notes Chapter 13 Amines students can recall all the concepts quickly.

Maharashtra State Board 12th Chemistry Notes Chapter 13 Amines

Amines are nitrogen-containing organic compounds having basic character.

1. Classification of amines :

2. Methods of preparation and the reactions of primary amines :

3. Electrophilite aromatic substitution :

4. Preparation and reactions of arene Diazoniuni salts :

By going through these Maharashtra State Board Secretarial Practice 11th Commerce Notes Chapter 9 Business Communication Skills of Secretary students can recall all the concepts quickly.

Maharashtra State Board Class 11 Secretarial Practice Notes Chapter 9 Business Communication Skills of Secretary

Communication-

• Latin word — ‘Communis’ meaning “Common”- “Shared by all”
• Definition : “It is an exchange of facts, ideas, opinions or emotions by two or more persons” — George R, Terry

Business Communication : Definition-
“It is the expression channeling, receiving and interchanging of ideas in commerce and industry.” — Brennar

Types of Communication-

1. Internal Communication
2. External Communication

Internal Communication:

• within various
• departments of an
• organization

External Communication

• between business
• organizations and outsiders.
• (banks, suppliers, creditors, Government, etc.)

Method of Communication-

1. Verbal or Oral Communication
2. Non – Verbal Communication
3. Written Communication

1. Verbal or Oral Communication

• Personal talks,
• Interviews,
• Speeches,
• Talking on telephone, etc.

2. Non – Verbal Communication

• body language
• facial expression
• eye contact
• silence, symbols, signs, gestures, etc.

3. Written Communicatin:

• reports
• letters
• circulars
• notices
• minutes, etc.

Merits of Written Communication-

• Accurate and Precise
• Economical
• Re-readab1e
• Completeness
• Eliminates personal contact
• personal contact
• Wide acces
• Documentary evidence

Essential Skills for Effective Communication-

• Listening
• body Language
• Give and Take Feedback
• Clear and Concise
• Empathy
• Confident
• Personal Touch

Business Letter: “It is a message that attempts to influence its recipients to take some action or attitude
desired by the sender.” – Robert

Layout of A Business Letter-

1. Proper arrangement of parts of a letter
2. Structural design of a. letter
3. Internal arrangement of matter

Layout of Business Letter-

1. Heading – name, address, telephone number, fax number, email Id, CIN, website, etc.
2. Date – British style or American Style
3. Reference number – left hand side below heading
4. Inside Address – name and address of receiver
5. Subject – shows purpose of the letter
6. Salutation – left hand margin below inside address
7. Body of the letter – introduction, main message and conclusion
8. Complimentary close – should match salutation
9. Signature – signature and name of person with designation
10. Enclosure – written on left hand side as ‘Enel’
11. Carbon Copy notation (C.C.) – left hand side below enclosure
12. Postscript – additional information after completion of letter
13. Identification Initials – initials of dictator and typist

Essentials of a Good Bussiness Letter (8 C’S)

1. Clarity
2. Cheerfulness
3. Conciseness
4. Consideration
5. Coherence
6. Completeness
7. Correctness
8. Courtesy

Physical Appearance of the Business Letter-

• Paper
• Typing
• Margin
• Envelope
• Spacing
• Folding
• Letterhead

Notice : It is an intimation given by the company to the member about day, date, time, place of the meeting and business to be transacted at the meeting.

Report: It is a statement of facts or opinion along with conclusion (with or without some recommendations)

Minutes :

• It is a written summary of the business transacted at the meeting.
• It is prepared by secretary, confirmed by members or directors, singed by a Chairman and counter signed by a secretary.
• It is written in past tense within 15 days of a meeting.
• It is written in minutes book in proper format.

Word Meaning:

entities – organization; verbal – oral; conveying – sending; circulars- written information distributed among people; layout – process of setting matter on a page; custom – procedure required: memos – a warning letter in written; draft – outline; authenticity – originality; factual – actual; precision – correctness; insistence – demands; economical – low cost; nominal – reasonable / less; blog – informal written material regularly updated on website; conferring – take part in a conference (meeting); pitch – the rate of sound produced low or high; gestures – to express an idea; empathy – ability to understand other; alignment – arranging in straight line; reference – mention; salutation – greeting; conclusion – finish / to end; brevity – in short; enclosure- additional documents attach to a letter; coherence – put in proper order.

By going through these Maharashtra State Board Class 11 History Notes Chapter 5 Janapadas and Republics students can recall all the concepts quickly.

Maharashtra State Board Class 11 History Notes Chapter 5 Janapadas and Republics

‘Jana’ and Janapadas:
Vedic people used the term Jana to designate a group of people, united under a common bond of singular kinship structure. Their settlement was known as ‘Grama’. A cluster of gramas consisting of the same Jana was known by the name of that particular Jana.

A region occupied by a Janas was called as Janapada. Gradually the Janapadas had more formal administrative structures transforming them into independent states. These were the first well-established states of ancient India. However, this does not necessarily mean that every Janapada evolved into an independent state.

Janapada:
The term ‘Janapada’ occurs in the Brahmana texts for the first time. Thereafter, it is frequently used in the Vedic literature and the epics – Mahabharata and Ramayana, as also in the Jain and the Buddhist literature. Considering the ancient Indian geographic perception with reference to the janapadas the said literature seems to divide the Indiansulcontinentjnto five sections:

1. ‘Praachya’ – of the east
2. ‘Praatichya’ – of the west
3. ‘Udichya’ – of the north
4. ‘Dakshina’ – of the south
5. ‘Madhyadesha – The central region.

Territoriality and Autonomous Functioning: It may be noted, that the sense of territoriality and the ensuing awareness of autonomy were the main factors responsible for the formation of ancient Janapadas in India. However, their administrative system was not much different from that of the Janas in the Rigveda.

The chief of the Janapada was known as ‘Rajan’. Two assemblies known as ‘Sabha’ and ‘Samiti’ were at the apex of all administrative decision-making processes, since the very beginning of the Vedic period.

Expansion and Development of the Janapadas: The expansion and development of the janapadas seem to have occurred in three different ways:
Expansion and development of a society formed into a Jana by uniting of a number of generations of a singular kula (family). For example, the Janapadas namely, Matsya, Chedi, Gandhara, Kashi, Kosala, etc.

Janapadas rising out of the union of more than one kula. For example, the Panchala janapada. Who were the five Janas united under the name of Panchalas, is not exactly known According to the renowned historian, Hemchandra Raychaudhuri following were the janas who merged together as Panchalas: Krivi, Turvasha, Keshi, Shrinajaya and Somaka. The more powerful janapadas conquered the less powerful ones.

Federation of States (Ganarajya):
‘Gana’ means the ruling class comprising members of equal social status. Similarly, ‘sangha’ means a state formed by many kulas or janapadas by coming together. By 6th century B.C.E. many sangharajyas had come into existence. There were three main types of the ancient federation of states in India.

• Ganarajya of the members of the same kula. For example, Malava and Shibi.
• Ganarajya created by more than one kulas coming together. For example, Vajji Ganasangha. It included eight kulas. Vajji, Lichchhavi, Dnyatruk and Videha were the important ganas among them.
• More than one ganrajyas coming together to create a sangharajya. For example, Yaudheya- Kshudrak Sangh.

Democratic States: Some of the gana sanghas were divided into regional zones called ‘Khanda’. They functioned through a group of elected individuals, who were found capable. Each of the elected members represented his respective khanda. These elected members were installed with collective authority for the smooth running of the gana sangha.

This was a democratic system. Ganasanghas which functioned in this democratic way existed in Punjab and Sindh at the time of Alexander’s invasion. Each elective representative of respective regional zone was designated as ‘Ganamukhya’. Every gana mukhya was the member of the assembly known as ‘Gana Parishad. The decisions made by the Gana Parishad were implemented by designated functionaries of various cadre. He was known as the ‘Adhyaksha’ or ‘Raja’.

Oligarchic States: In this type the elite class in the society held all the powers of decision-making and administration. Panini and Kautilya mention them as ‘Rajshabdopajivi’ Sangh. Panini includes Vajji, Andhaka, Vrishni, Yaudheya in the Rajashabdopjivi type. Kautilya includes the Vrijji or Vajji, Madrak, Kuru, Panchala, etc. in this type. This type of gana sanghas were more prevalent in the eastern region of Uttar Pradesh and Bihar.

Glossary:

→ Kula – Clan or family.

→ Grania – Settlement.

→  Rajan – Chief of Janapada.

→ Gana – Refers to the ruling class comprising members of equal status.

→  Khanda – Regional zones.

→  Varta – Means trade or commerce.

By going through these Maharashtra State Board 12th Science Biology Notes Chapter 5 Origin and Evolution of Life students can recall all the concepts quickly.

Maharashtra State Board 12th Biology Notes Chapter 5 Origin and Evolution of Life

Origin of life (Protobiogenesis)-

1. Attributes of living organisms : Responsiveness, growth, metabolism, energy transformations and reproduction.
2. Various theories and hypotheses to propose origin of life :

Chemical Evolution of Life (Self-assembly theory of origin of life)-

1. Theory of biochemical origin of life : Life originated on earth by combinations of several chemicals through constant chemical reactions over a long period of time.
Formulated by Haeckel, developed by Alexander I. Oparin (1924) and J. B. S. Haldane (1929).

2. The steps in the process of chemical evolution :

• Origin of Earth and Primitive atmosphere : Big-Bang theory of Georges Lemaitre (1931). Formation of reducing atmosphere.
• Formation of ammonia, water and methane : Formation of CH₄, NH₃, H₂O and H₂S.
• Formation of simple organic molecules : Formation of monosaccharides, amino acids, purines, pyrimidines, fatty acids, glycerol, etc. Formation of water bodies resulting into ‘hot dilute soup’ or ‘primitive broth’.
• Formation of complex organic molecules : Formation of complex organic molecules like polysaccharides, fats, proteins, nucleosides and nucleotides. Protoproteins → proteins.
  Formation of protein molecules : Landmark in the origin of life.
• Formation of Nucleic acids : Formation of Nucleotides→nucleic acids (RNA, DNA) →acquired self-replicating ability→ fundamental property of living form.
• Formation of Protobionts or Procells : First form of life called protobionts was formed from nucleic acids by coacervation.

Protobionts : Prebiotic chemical aggregates having some properties of living system.
Protobionts also called Coacervates (Oparin) and protenoids or microspheres (Sidney Fox)

Coacervates and microspheres were non¬living colloidal aggregations of lipids and proteinoids respectively. They turned into eobionts or protocell.

Showed growth and division and hence considered as first primitive living system.

• Formation of first cell : First cell developed by formation of RNA and DNA system. First cell was anaerobic, heterotrophic and obtained energy by chemoheterotrophic processes.

Stanley L. Miller and Harold C. Urey provided the first experimental evidence for Oparin’s chemical evolution theory.

3. RNA World Hypothesis :

• First proposed by Carl Woese, Francis Crick and Leslie Orgel in 1960.
• Sidney Altman and Thomas Cech independently found out that RNA can also act as biocatalyst which is termed as Ribozyme.
• Early life must have been based exclusively on nucleic acids, most probably RNA.

Organic Evolution-

• Evolution (Latin word, e = from; volvere = to roll) : The act of unrolling or unfolding of nature.
• Organic evolution : Slow, gradual, continuous and irreversible changes through which the present-day complex forms of the life developed (or evolved) from their simple pre¬existing forms.
• Charles Darwin’s definition of evolution :
  ‘Descent with modification’.
• Lamarck’s theory (Theory of origin of acquired characters/inheritance of acquired characters and use and disuse of organs) : The traits are acquired due to internal force, changes in environment, new needs and the use and disuse of organs. This gives rise to new species after several generations. Lamarckism was disproved by August Weismann.
• Weismann’s theory of Germplasm : Variations produced in somatic cells (somatoplasm) are not inherited while variations produced in germ cells (germplasm) are inherited to next generation.

Darwinism-

1. Darwinism or theory of origin of species by Natural Selection.
2. Darwin’s book : ‘The origin of species by Natural Selection’, wrote in 1859 after observations of variations between the tortoises and finches on Galapagos islands.
3. C. Lyell’s viewpoint on which Darwin’s theory was based : The natural forces that existed in the past are same as those existing at present.
4. Wallace also made similar observations.
5. R. Malthus provided the idea that increase in human population leads to competition and struggle for existence of human species.
6. Five main postulates of Darwinism :

• Overproduction (Prodigality of nature)
• Struggle for existence
• Organic variations
• Natural selection (H. Spencer termed natural selection as ‘survival of fittest’)
• Origin of new species

7. Evidences Darwinism include :

• Evolution of long-necked Giraffe came to existence.
• Black colour peppered moths evolved gradually as new species.
• DDT resistance

8. Drawbacks and Objections to Darwnism :

• Darwin wrongly considered minute non- heritable fluctuating variation as principal factors. They do not form part of evolution.
• He did not distinguish somatic and germinal variation and considered all variations are heritable.
• He did not explain the ‘arrival of the fittest’. He did not explain the cause, origin and inheritance of variations and of vestigial organs.
• He could not explain the extinction of species.
• Intermediate form during evolution were not recognised.
• He could not explain existence of neutral flowers and the sterility of hybrids.

Mutation Theory-

1. Hugo de Vries proposed mutation theory based on his observations on Oenothera lamarckiana.
2. Though offspring resemble their parents in many characters, some sudden and spontaneous variations are seen in them, which is said to be mutations or discontinuous variations.
3. Main features of mutation theory :

• Large, sudden and discontinuous variations, inheritable changes in a population which provide the raw material for organic evolution.
• Mutation may be useful or harmful. Useful mutations are selected by nature.
• Accumulation of useful mutations over a period of time leads to the origin and establishment of new species, while harmful mutations are eliminated by nature or can remain in population.

4. Objections to Mutation Theory :

• The large and discontinuous variations were chromosomal aberrations which bring about minor changes.
• Rate of mutation is very slow.
• Chromosomal aberrations are unstable and hence not important in evolution.

5. Speciation (Formation of new species) :

• Small Darwinian variations are directional. Variations due to mutations are large, sudden, random.
• Darwin’s opinion : Gradual, inheritable variations over a long period of time, lead to speciation.
• De Vries’s opinion : Mutations cause speciation.
• Saltation : A single step large mutation.

Modern Synthetic Theory of Evolution-

1.  R. Fischer, J. B. S. Haldane, T. Dobzhansky, J. Huxley, E. Mayr, Simpson, Stebbins, Fisher, Sewall Wright, Medel, T. H. Morgan, etc. together have synthesised the modern theory of evolution.
2. Stebbins suggested five key factors for evolution : Gene mutations, chromosomal mutations, genetic recombinations, natural selection and reproductive isolation → together bring about evolution of new species.
3. Population : All individuals of the same species form population.
4. ‘Mendelian population’ : Small groups of interbreeding populations.
5. Gene pool : Gene pool is the total genetic information or sum total of genes of all individuals in a Mendelian population.
6. Factors affecting gene pool : Migration, replacement of one generation by another in the Mendelian population.
7. Gene frequency : The proportion of an allele in the gene pool, to the total number of alleles at a given locus.
8. Factors of Modern synthesis theory:

• Gene Mutation : Sudden permanent heritable change in the genetic material is called mutation. Single gene mutations are called point mutations. Chromosomal aberrations and ploidy too cause mutations. All mutations lead to variations.
• Genetic recombination : Crossing over in sexually reproducing organisms cause variations , during gamete formation. Crossing over also create recombination.
  Crossing over : Exchange of genetic material occurs between non-sister chromatids of homologous chromosomes.
• Gene flow : Movement of genes into or out of a population. Migration of organism, or gametes (dispersal of pollens) or segments of DNA (transformation).
• Genetic drift : Any random fluctuation (alteration) in allele frequency, occurring in the natural population by pure chance. Smaller populations may show genetic drift.
• Chromosomal aberrations : The structural, morphological change in chromosome due to rearrangement cause chromosomal aberrations.

Types of aberrations :

• Deletion : Loss of genes from chromosome.
• Duplication : Repetitions of genes or doubling of chromosome number.
• Inversion : Sequence of the genes get inverted due to 180° twist.
• Translocation : Transfer (transposition) of a part of chromosome or a set of genes to a non-homologous chromosome.

Natural selection : Main driving force behind the evolution. It brings about evolutionary changes by favouring differential reproduction of genes that bring about changes in gene frequency from one generation to next generation. The ‘fittest’ (well adapted) survives and leaves more progeny. E.g. Industrial melanism in peppered moth (Biston betularia) is example of natural selection in action.

Isolation : The separation of the population of a particular species into smaller units which prevents interbreeding between them is isolation.

Isolating mechanisms : Barrier which prevents gene flow or exchange of genes between isolated populations.

Type of isolating mechanisms :

Mechanism of organic evolution-

1. During evolution population evolves and not the individual.
2. Basic processes which bring about evolution : Mutations, gene recombination, gene flow (migration),
genetic drift, natural selection, isolation and speciation.

Hardy-Weinberg’s principle-

Hardy-Weinberg’s equilibrium/principle/law states that ‘at equilibrium point both the gene (allele) frequency and genotypic frequency remain constant from generation to generation’, only in diploid, sexually reproducing, large, free interbreeding population if mating is random and in absence of selection and other evolutionary forces.
Hardy-Weinberg equilibrium equation : p² + 2pq + q² = 1

Adaptive Radiation-

Adaptive radiation is the process of evolution which results in transformation of original species to many different varieties. E.g. (1) Darwin’s Finches on Galapagos islands. (2) Australian Marsupials.

Evidences of organic evolution-

Evolutionary evidences are based on following types of disciplines : Palaeontology, comparative anatomy, embryology and molecular biology

Speciation-

• Speciation : The process of formation of a new species from the pre-existing species.
• Species : A group of similar organisms that can interbreed and produce a fertile offspring in nature.
• Types of speciation:

Geological time scale –

Human Evolution-

1. Major changes in evolutionary development of man :

• Increase in size and complexity of brain and enhanced intelligence with increased cranial capacity.
• Bipedal locomotion, erect posture.
• Opposable thumb.
• Shortening of forelimbs and lengthening of hind limbs.
• Development of chin. Orthognathous face.
• Broadening of pelvic girdle, development of lumbar curvature.
• Articulated speech, art, development of tools, social and cultural development.

2. Classification of mammals:

3. Origin and evolution of human being :

(1) Order Primates is divided into two suborders – Prosimii (including lemurs, lorises : and tarsiers) and Anthropoidea (including : New world monkeys – Ceboidea, Old world monkeys-Cercopithecoidea, Apes and :
Man – Hominoidea).
(2) Hominoidea evolved in Miocene in three • separate lines are shown as under :

• Hyalobatidae – Gibbons
• Pongidae – Gorilla, Chimpanzee and Orangutan
• Hominidae – Primates with human characteristics.

4. Palaeontological evidences of human • evolution : The available fossils are skulls, • mandibles, teeth, bones like humerus, femur and stone implements.
5. Important stages in the origin of man :

• Ape like stage : Dryopithecus
• Men-like stage : Ramapithecus
• Connecting link between ape and man : Australopithecus.
• Handy man : Homo habilis
• Ape man : Homo erectus
• Advanced prehistoric man : Homo : neanderthalensis (Neanderthal man)
• Modern man : Homo sapiens

By going through these Maharashtra State Board 12th Science Chemistry Notes Chapter 11 Alcohols, Phenols and Ethers students can recall all the concepts quickly.

Maharashtra State Board 12th Chemistry Notes Chapter 11 Alcohols, Phenols and Ethers

Introduction, Classification-

Alcohols/Phenols:

• Monohydric alcohols/phenols
• Dihydric alcohols/phenols
• Trihydric alcohols/phenols

Monohydric alcohols:

• Primary alcohol
• Secondary alcohol
• Tertiary alcohol

Ethers:

• Simple ethers R—O—R
• Mixed ethers R—O—R’

Methods of preparation and the reactions of alcohols-

Methods of preparation of phenol-

The reaction of phenol-

Classification and Important Reactions-

(1) Methods of preparation of ethers:

(2) Reactions of ethers:

Anisole-

By going through these Maharashtra State Board 12th Science Biology Notes Chapter 10 Human Health and Diseases students can recall all the concepts quickly.

Maharashtra State Board 12th Biology Notes Chapter 10 Human Health and Diseases

Introduction-

1. Health : World Health Organization (WHO) define health as ‘the state of complete physical, mental and social well-being and not merely the absence of disease or infirmity’.
2. Health is metabolic and functional efficiency of living organisms.
3. Hygiene : Science of rules of health.
4. Important factors to achieve good health : Hygienic balanced diet, clean drinking water, personal and community hygiene, regular physical exercise, knowledge about diseases and their effect on body, proper disposal of wastes and control of vectors.
5. Immune system : The ability to resist almost all types of these foreign bodies is possible due
   to immune system. It protects human beings from various pathogens or infectious agents.
6. Resistance : The ability to prevent the damage or disease, through our defence mechanism.

Immunity-

1. Immunity: Immunity is the resistance exhibited by the host towards infections caused by pathogens and their products.
2. Immunology: Study of immune system, immune responses to foreign substances and their role in resisting infection by pathogens.
3. Edward Jenner : Started the concept of immunity. Cowpox vaccine was developed by him.
4. Antigen : Any foreign substance invading body and capable of stimulating an immune response.
5. Antibody : The protective chemicals produced by immune cells in response to antigens are called antibodies.

6. Types of immunity-

7. Innate immunity :

• Inborn immunity which is non-specific and not affected by immunization.
• The barriers of innate imunity are as follows:
  

8. Acquired immunity :

(1) Specific or adaptive immunity acquired during lifetime due to infections.
(2) It involves formation of antibodies from the destruction of foreign antigens.
(3) Unique features of acquired immunity are specificity, diversity, discrimination between self and non-
self and memory.
(4) Types of acquired immunity :

9. Cells of immune system :

10. Mechanism of action of B-lymphocytes to antigens :

B-lymphocytes → sensitized directly by antigens and helper T-cells.
Activated B-lymphocyte → multiplies rapidly → Clone of plasma cells and memory B-cells produced → Plasma cells produce → Glycoproteins, called antibodies → Antibodies circulated through humor/ body fluids like blood and lymph → The antibody → bind to a cell membrane or they remain free.

11. Three main functions of free antibodies :

12. Vaccination :

• Vaccination : Administration of inactivated pathogen or antigenic protection of particular pathogen for protecting against a particular pathogen, is called vaccination.
• Vaccine : Inactivated pathogen or antigens of a specific disease.
• Vaccination is a primary prevention as it helps the body to recognize and eliminate pathogenic organism.
• Disease control on mass scale is done through vaccination. E.g. Measles, polio, tetanus and whooping cough, tuberculosis, etc. are prevented through vaccination.

Structure of antibody-

1. Antibodies are highly specific glycoproteins which can neutralize specific antigens.
2. Chemically they are Immunoglobulins (Igs), produced after antigenic stimulation.
3. Production in plasma cells which are formed by B-lymphocytes.
4. Rate of production of antibodies is very rapid, i.e. about 2000 molecules/second.
5. Structure of antibody :

• ‘Y’-shaped molecule. Having four polypeptide chains : Two heavy or H-chains and two light or L-chains.
• Y-structure formed from four polypeplidc chains are held together by disulfide bonds (-s-s-).
• Hinge : This is region holding together arms and stem of antibody.
• Two distinct regions : Variable region and the constant region.
• Paratope : This is antigen binding site present in variable region.
• Epitope : Antigen has antigenic determinant site, called epitope.
• Bivalent antibodies : Antibodies having two antigen binding sites.
• Serology: Study of antigen-antibody interactions.
• FormatIon of antigen-antibody complex: Epitopes (On antigens) and paratopes (on antibody) react with each other. Each antibody Is specific for specific antigen due to variable regions having small variations. Specific antibody binds to specific antigen forming an antigen-antibody complex.
• Antigen on Blood Cells: Antigens (A, B, D) on the surface of human red blood cells : responsible for different blood groups.
•  Blood group systems : ABO, Rh. Duffy, Kidd. Lewis, R MNS, Bombay blood group. etc.

(12) ABO Blood Groups:

(13) Rh factor :

• Landsteiner and Wiener (1940) discovered Rh factor or D antigen on the surface of RBCs of Rhesus monkey. Hence called Rh factor.
• Rh positive (Rh+ve) person has D antigen. Rh negative person lacks it.
• Rh (D) antigen induces a strong immunogenic response when introduced into Rh-ve individuals.
• Haemolytic diseases of the newborn (HDN), or erythroblastosis foetalis occurs when an Rh —ve mother conceives Rh + ve foetus.

Common Human Diseases-

10. Cancer : Cancer is caused due to abnormal, uncontrolled and purposeless division of cells which may form tumour.

(1) Neoplasm : Masses of tissue which form lumps due to uncontrolled cell division.
(2) Oncologists : Oncologists are the physicians and researchers who specialize in the study, diagnosis, treatment and prevention of cancer.
(3) Tumour is mass of undifferentiated cells.

(4) Two types of tumours :

Benign / Non-malignant Tumour:

• Slow growth and Larger size
• Does not spread to other body parts.
• Usually harmless.
• But may sometimes become malignant.
  e.g. Adenoma and Fibroid.
• Brain tumour can be fatal, though it is benign.

Malignant tumour or cancer”

• Rapid growth and not much bIgger.
• Spreads to other body parts. via blood or lymph. (The process of metastasis)
• Usually harmful.
• Overcrowding and disruption of normal cells.

(5) Types of Cancer : Five main types according to tissue on which they thrive.

(6) Causes of Cancer : Also called carcinogenic factors.

(7) Treatment of Cancer :

• Chemotherapy
• Radiotherapy
• Surgery
• Immunotherapy
• Supportive therapy

11. AIDS :

(1) AIDS : Acquired immuno deficiency syndrome, fatal and incurable illness caused by a retrovirus (ss RNA) called HIV (Human immunodeficiency virus).
Body’s immune system is weakened increasing vulnerability causing many life-threatening opportunistic infections, neurological disorders and malignancies.

(2) Structure of HIV :

• Spherical, 100 to 140 nm in diameter, with centrally located two ss RNA molecules and reverse transcriptase enzymes.
• Covering of two layers of proteins.
• The outer layer is of matrix protein (pi7) with additional layer of lipid.
• Impregnated with glycoprotein GP120 and GP 41.
• Inner layer is capsid protein (p24)
• Replication of HIV in dividing T₄ lymphocytes. They remain in latent state in lymphoid cells.

(3) Blood, semen and cerebrospinal fluid (CSF) show maximum concentration of HIV in infected person. Lesser extent seen in tears, milk, urine, saliva, cervical and vaginal secretions.

(4) Transmission of virus :

• Unsafe sexual contact : Oral, vaginal and anal sex.
• Blood : Blood transfusions or sharing syringes, needles, etc.
• Transplacental (From mother to child during pregnancy via placenta) and by nursing mother through breast milk.
• Accidental needle injury, artificial insemination with infected semen and transplantation with infected organs.
• Through urine, tears, saliva, breast milk and vaginal secretions if these secretions enter passes in the body through injury.

(5) Clinical manifestations : Four broad categories.

(6) Preventive measures :

• Prevention is the only measure as there is no cure for AIDS.
• Education of highrisk group, about HIV transmission.
• Disposable needles and syringes.
• Sexual habits to be modified.
• No sharing of toothbrushes, razors, etc.
• Blood to be screened before receiving.

Routine screening must for –

• Blood donors.
• Organ donors (kidney, liver, lung, cornea).
• Donors of semen and growth hormone.
• Patients undergoing haemodialysis.
• Pregnant females in highrisk group.

(7) Laboratory diagnosis :

• ELISA (Enzyme-Linked Immunosorbent Assay) : This test is for detection of AIDS.
• Western Blot : Second and confirmatory test which detects specific antibody to viral core protein and envelope glycoprotein.

(8) Treatment of AIDS : Antiretroviral therapy (ART) : Antiretroviral drugs for reducing viral load and prolong the life of HIV patient. E.g. TDF (tenofovir), EFV (Efavirenz), Lamivudine (3TC), etc.

Adolescence-

1. Adolescence Is transitional stage of physical and mental development during puberty and the legal adulthood. National youth policy defines phase of adolescence during 13—19 years. This period Is marked with sexual and reproductive maturity mental development, adalt Identity and transition from socioeconomic and emotional dependency to relative independence.

2. Stages of Adolescence :

3. Physical changes of adolescence:

• Growth spurt.
• Sexual development
• Emotional and social changes

4. Mental Health and Adolescence:

• Confusion, irritation. moodiness, frustration, nausea, less concentration, hyper activities, anger. effects on lifestyles like obesity, addictions, accidents, leading to ill health. etc. are common problems in adolescent age.
• Psychoses or neuroses may appear.
• Psychoses include delusions, hallucinations. disturbance In the thinking process, etc.
• AmnesIa (loss of memory). Bullirnia (extreme over indulgence in food), Anxiety (fear or apprehension), Anorexia nervosa (emotional aversion to food) depression (sadness, inactivity reduced to enjoy life, etc.), illusions, hallucination, etc.
• Characterized by number of cognitive, emotional, behavioural, physical and attitudinal changes.
• Parental communication and other conditions mould the adult personality.
• Improper peer pressure may result into addictions, like smoking, taking drugs, etc.

5. Treatment: Treatment of such disorders should be done only through counselling and not medicines with due respect to rights of children. Mental health Gap Action Programme (mhGAP) gives the guidelines as per WHO for treating such cases. Parental relations are most important in any treatment.

Addiction –

1. Addiction : Compulsive use of substance despite its harmful consequences is addiction. Addiction cause the impairment of physical, physiological and psychological functions of the body.
2. Addictive substances : Alcohol, opioids, cocaine, nicotine and some behaviours such as gambling.
3. All addictive behaviours share key neurobiological features, involving brain pathways of reward and reinforcement.
4. Neurotransmitter dopamine released during motivation.
5. Neurological changes are reversible after the substance abuse or behaviour is discontinued.
6. Causes of substances abuse during adolescence :

• Parental neglect and insufficient parental supervision and monitoring.
• No communication between child and parents.
• Absence of poorly defined rules.
• Family conflicts.
• Favourable parental attitudes towards alcohol and drug uses.
• Risk taking behaviour.

7. Measures to control drug abuse :

• Always remember ‘Prevention is better than cure’.
• Children should not be pressurized. Over expectations from them should be avoided.
• Suitable education and counselling whenever required.
• Sublimation and channelization of the energy of child in sports, studies and other constructive activities.

Drugs Abuse-

1. Drugs and alcohol use in youth leads to many harmful effects. Improper lifestyle with dangerous behaviour pattern should not be accepted as it is hazardous for all.
2. The drugs of abuse are opioids, cannabinoids and alkaloids of coca and hallucinogens.

3. Addiction and Dependence :

• Inherent addictive nature of alcohol and drugs result into psychological attachment to certain effects-such as euphoria and a temporary feeling of well-being.
• Repeated use of drugs increases the tolerance level of the receptors present in our body.
• Person getting addicted, starts self-destructive behaviour.
• Withdrawal symptoms : If regular addictive substance is discontinued, it results in withdrawal symptoms. All the symptoms seen in such person is called withdrawal syndrome, which is characterized by anxiety, trembling, nausea and sweating.

4. Effects of Drug/Alcohol Abuse :

• Reckless behaviour, vandalism and violence.
• Excessive doses of drugs can cause coma and death due to respiratory failure, heart failure or cerebral haemorrhage.
• Overdose and even deaths occur if there is weird combination of drugs and alcohol.

5. Warning signs of drug and alcohol abuse among youth :

• Drop in academic performance.
• Unexplained absence from school/college.
• Lack of interest in personal hygiene, withdrawal, isolation, depression, fatigue, aggressive and rebellious behaviour, deteriorating relationships with family / friends.
• Loss of interest in hobbies.
• Change in sleeping and eating habits.
• Fluctuations in weight, appetite, etc.
• May turn to crime for money.

6. Other hazards : Intravenous injections of drugs can cause serious infections like HIV and hepatitis B.

7. Long-term effects : Loss of equilibrium, liver cirrhosis, pancreatitis. Damage to nervous system and liver (cirrhosis). Use of drugs and alcohol during pregnancy adversely affects the foetus.

8. Performance enhancers :

• Sportspersons use drugs to enhance performance.
• Narcotic analgesics, anabolic steroids, diuretics and certain hormones to increase muscle strength and bulk and to promote aggressiveness and overall improvement in their performance.
• Anabolic steroids have side effects :

(a) Effects in females : Masculinization in females, increased aggressiveness, mood swings, depression, abnormal menstrual
cycles, excessive hair growth on the face and body, enlargement of clitoris, deepening of voice.

(b) Effects in males : Acne, increased aggressiveness, mood swings, depression and reduction of size of the testicles, decreased sperm production, kidney and liver dysfunction, breast enlargement, premature baldness, enlargement of the prostate gland.

9. Prevention and Control : Habits such as smoking, taking drug or alcohol should be avoided right from young age. Identify the situations which can form addictions and take remedial measures. Help from parents and teachers should be sought.

By going through these Maharashtra State Board 12th Science Chemistry Notes Chapter 9 Coordination Compounds students can recall all the concepts quickly.

Maharashtra State Board 12th Chemistry Notes Chapter 9 Coordination Compounds

Coordination compound : It consists of a central metal atom or ion surrounded by atoms, molecules or anions called ligands bonded by coordinate bonds, e.g. cisplatin, Pt(NH3)2Cl2, [Cu(NH3)4]S04.

According to Werner’s theory, metal atom or ion in the complex has primary valence (outer sphere) and secondary valence (inner sphere).

Coordination number (C.N.) : The number of ligand donor atoms directly bonded to the central metal atom or ion by coordination bonds or number of electron pairs involved in the coordinate bonds is coordination number (C.N.).

Ligands:

• Monodentate ligands (Cl^–, OH^–, NH₃, H₂O, etc.)
• Bidentate (en, C₂O₄^2- etc.)
• Tridentate (dien)
• Tetiadentate (trien)
• Hexadentate (EDTA)

Classification of complexes on the basis of types of ligands :

• Homoleptic complexes Ni(CO)₄, [CO(NH₃)₆]Cl₃
• Heterleptic complexes [CO(NH₃)₄Cl₂H₂O]Cl

Classification of complexes on the basis of charge :

• Cationic sphere complexes, [Zn(NH₃)₄]²⁺ , [CO(NH₃)₅Cl]²⁺
• Anionic sphere complexes, [Ni(CN)₄]^2-, [Fe(CN)₆]^3-
• Neutral sphere complexes, [Pt(NH₃)₂Cl₂], [Ni(C0)₄]

Effective atomic number : EAN = Z – X + Y

Isomerism in complexes :

(1) Stereoisomerism :

• Geometrical isomerism
• Optical isomerism

(2) Structural isomerism :

• Ionisation isomerism
• Linkage isomerism
• Coordination isomerism
• Solvate isomerism

Bonding in complexes:

• Valence bond theory (VBT)
• Crystal field theory (CFT)
• Ligand field theory (LFT)
• Molecular orbital theory (MOT)

Valence bond theory (VBT) : A central.metal atom or ion undergoes hybridisation like sp3, dsp2, d2sp3, etc. forming hybridised orbitals to accommodate the lone pairs of electrons from the ligands.

Inner complex : (n — 1)d orbitals of metal are used.
Outer complex: nd orbitals of metal are used.

Crystal field theory (CFT) :
Degenerate d-orbitals: d_xy, d_yz, d_zx, d_{(x² – y²)} and d_z²

Crystal field splitting:

(1) For octahedral complex:

(2) For tetrahedral complex :

Factors affecting the stability of the complex :

1. Charge to size ratio of the metal ion
2. Nature of ligands

Applications of the coordination compounds:

• In biology
• In medicines
• To estimate the hardness of water
• In electroplating