10th | Aster Classes

SSC, CLASS, 10th, EXAMINATION, DATE, ANNOUNCED, Maharashtra, board, 2020-21,

Written exams of Secondary School Certificate (SSC) Class X will be held from April 29, 2021, to May 31, 2021.

Results are expected to be announced in the last week of August 2021.

All exams would be conducted in compliance with the COVID-19 norms.


Balbharati solutions, for, Social Science, History, and, Civics, 10th, Standard, SSC, Maharashtra, State, Board, chapter 4, Social, and, Political Movements, Latest edition,

Exercise | Q 1.1 | Page 96

Choose the correct option from the given options and complete the sentence. 

____________ is the main demand of farmers movement. 

Right to cultivate on the forest land 

To get the right price for agricultural product 

Protection of consumers 

Building of dams

SOLUTION

To get the right price for agricultural product


To increase agricultural production and become self-sufficient with regard to food grains ____________ was initiated. 

Water revolution 

Green revolution 

Industrial revolution 

White revolution

SOLUTION

Green revolution


Exercise | Q 1 | Page 96

Write note on : 

Tribal movement

SOLUTION

The origin of Tribal movement dates back to the pre-independence days. The British government had deprived tribal people of their rights to livelihood on forest resources and as a result of that, a tribal uprising took place in various parts of the country. It included tribes like Kolam (Chota Nagpur), Gond (Orissa), Koli Bhilla Ramoshi (Maharashtra), Santhal and Munda (Bihar).

The main demand of the tribal movement is for the government to accept their rights over forests, they should be allowed to collect forest produce and cultivate forest land.


Workers movement

SOLUTION

Workers movement in India was organized under Trade unions that saw its birth in the background of industrialization in British India.

Industrial workers frequently went on strike for their demands of better wages and improved working hours.

One such incident was reported as the railway workers’ strike in 1899.

The first organization for resolving workers’ issues was established in 1920, known as the All India Trade Union Congress.

In the post-independence era, trade unions got more effective in 1960s and 1970s, organizing several agitations but saw its disintegration in 1980s and its steady decline in the face of globalization in 1990s. Some of the concerns of the workers’ movements are:

• Unstable employment conditions

• Contract labour and financial insecurities of workers

• Absence of legal protection for workers

• Long working hours

• Insecurities at workplace

• Health hazards at work place, etc.


Answer the following question in brief. 

Explain the activities/role/functions  of environmental movement.

SOLUTION

The environmental movement is an important step towards environmental protection which is recognized as a global concern. Its working is organized on several levels (local, national, international) to prevent environmental degradation. It aims to create awareness and drive policy making on issues like sustainable energy, protection of forest and biodiversity, severe effects of pollution and degradation of air, water, soil etc.


Explain the nature of farmers movement in India.

SOLUTION

The history of farmers’ movement in India dates to the time of our independence struggle. It was inspired by the thoughts of Mahatma Phule, Justice Ranade and Mahatma Gandhi against the anti-agriculturist policies of the British. It has continued to be active and became more effective after the Green Revolution which increased the economic gap between rich farmers and poor farmers. Some of the demands of the farmers’ movements are:

• Appropriate prices for agricultural goods

• Industry status for Agriculture

• Implementations of the recommendations of the Swaminathan Commission report

• Debt relief and debt cancellation

• National policy for Agriculture


For which reforms were the women’s movement in the pre-independence period fighting?

SOLUTION

The women’s movements in the pre-independence period were fighting for eliminating injustice and exploitation against women, helping them lead a respectful and socially active life. Some of the reforms it demanded were:

• Widow re-marriage

• Women education

• Right to vote

After Independence, women were granted equal political rights by the constitution, however, the social struggle for equality continued.


Explain the following statement by giving reason. 

Movements are important in a democracy.

SOLUTION

Movements are important in a democracy because:

1. Different social problems are discussed through these movements.

2. It is a way of attracting the attention of Government towards a cause.

3. The Government & common people get more necessary information about the issues through leaders and activists.

4. It helps the government take an informed decision on the subject.

5. Right to protest is an important democratic right, hence social movements strengthen democratic processes.


Movements do not need a strong leadership.

SOLUTION

Movements need a strong leadership to keep it active and effective. A Movement is a collective struggle, people need a strong leader for right guidance to reach their objective.

For instance, India’s freedom struggle was marked with emergence of a strong political leadership in the twentieth century (1900s), prior to that the independence efforts were scattered in regions and divided in their political stances. It found a direction in non-violence and political non-cooperation under the leadership of Gandhi. While multiple groups continued to fight for India’s freedom in their respective ways, the common masses found their aspirations aligned with the Gandhian movement for his charismatic leadership.


Consumer movement came into existence.

SOLUTION

The consumer movement came into existence in 1986 with the Consumer Protection Act to address cases of frauds in the economic exchanges. It takes each citizen to be a consumer and has a broader objective is to protect the consumer against adulteration and frauds, understanding the changing nature of consumer grievances.

The Consumer Protection Act proved its importance with the economic liberalization of India in 1990s. The consumer forums proved to be a good system of check and balance into quality control and after sales services in the market place.


Write a report on movements in your area which are working to resolve general problems.

SOLUTION

In my city, Jodhpur, currently the initiative has been taken by the people to clean in area (Madhuban) by making arrangements to dump the waste rather than throwing it in the corners of the road.

REPORT ON CREATING ARRANGEMENTS FOR DUMPING WASTE

Recently when I visited my town, I found out that to resolve the general problem of dumping waste, the people are taking initiative in various ways. As the situation in this area was worsening, some people took the initiative to solve this problem.

In Madhuban, People were dumping waste in their nearby corners as the dustbins were already filled. Municipal people didn’t bother to clean up the area at least once on an alternate day depending upon the availability of dustbins provided in the location. Hardly, there was proper facility provided to dump the waste. People had to go to the other areas to dump waste as there were not enough dustbins provided.

There were some people who took initiative firstly by complaining to the Municipal Corporation to provide a required number of dustbins in Madhuban (at least in every colony). Some people started to travel with their own carrier tempo with a song playing with lyrics “Sunlo bhaiya sunlo bhabhi sunlo bhaiyaji, kachre waale dabbe me tum Kachra daalo ji”. They go to every colony with this temp and charge 50 Rs a month for this. They also take waste bags kept outside the houses and charge extra 10 Rs for this otherwise the individual has to dump waste on his own when the tempo comes outside the home.


Prepare a format of a complaint you will submit under consumer protection act if you are cheated in purchase of vegetables or grains.

SOLUTION

CASE: Miss Devika Pillai purchased Grains from Mr. Pankaj & Co. operating in the same town, in January 2019. The grains purchased contained chemicals and colours to make it look more shiny and fresh. As a result, Miss Devika Pillai approaches the District forum.

COMPLAINT PETITION

For being cheated in the purchase of grains

BEFORE THE DISTRICT FORUM CONSUMER DISPUTES REDRESSAL FORUM, <JODHPUR>

Consumer dispute case no. 1234/2019

A petition under Section-11 Consumer Protection Act

And in the matter of :

Miss Devika Pillai

3 GHA 22 Madhuban, Basni, 1st phase, Jodhpur (Raj.)

Vs

Owner of the Shop

Mr. Pankaj & Co.

3B12, Chopasini Housing Board, Jodhpur.

To,

Hon’ble President and

Members of the District Forum

Jodhpur

May it please your honours:

This complaint petition is being filed on behalf of Miss Devika Pillai 3 GHA 22 Madhuban, Basni, 1st phase, Jodhpur (Raj.) referred hereafter as Complainant, and is as follows :

1.0 That this complaint Petition is being filed under Sec.

2 (1)(b)(i) of the Consumer Protection Act.

2.0 That the opposite party is engaged in the business of selling vegetables and grains in the known markets, apart from other activities.

(Narration of the Incident)

3.1 That on 5th January. 2019 (date of purchasing grains), the complainant deposited a sum of Rs 1 lakh to purchase 40 kg of Grains and the receipt (receipt no. -228) has been provided for this. A Photocopy of the said receipt is furnished at Annexure-I.

3.2 After knowing about being cheated, when the complainant approached the shopkeeper, he initially refused to talk on this matter and later denied of such act done by him. Hence, the complainant wrote to the shopkeeper, requesting to take an immediate intervention. Copy of the letter has been furnished at Annexure – II.

3.3 As a result, till date O.P No. 1 did not bother to honour the directives of a complainant, and the complainant is still didn’t receive his money back.

3.4 That the O.P had tried to sell grains which are unhealthy to consume by the complainant.

PRAYER

In the view of the submissions contained in the preceding paragraphs, the complainant most respectfully prays to the Hon’ble Forum to direct the Opposite Parties to:

(a) refund the cost of the purchased grain, Rs. <1 lakh> along with 10% interest;

(b) to pay a sum of Rs. 10,000/- towards the physical strain and mental agony suffered by the complainant and his family members (compensation); and

(c) to pay a sum of Rs. 1,000/- towards cost of this petition (Cost);

For which act of kindness, the complainant shall, as is duty bound, ever pray

Devika Pillai


Balbharati, solutions, for, Social, Science, History, and, Civics, 10th, Standard, SSC, Maharashtra, State, Board, chapter 2, The Electoral Process, [Latest edition],

Exercise | Q 1.1 | Page 80

Choose the correct option from the given options and complete the sentence. 

The Election Commissioner is appointed by the _______

President 

Prime Minister 

 Speaker of Loksabha 

 Vice President

SOLUTION

President

_________ was appointed as the first Chief Election Commissioner of independent India. 

Dr. Rajendra Prasad 

T.N. Sheshan 

Sukumar Sen 

Neela Satyanarayan

SOLUTION

Sukumar Sen

Constituencies are created by _________ committee of the Election Commission. 

Selection 

Delimitation 

Voting 

Timetable

SOLUTION

Delimitation


State whether the following statement are true or false. Give reason for your answer

The Elections Commission lays down the code of conduct during elections.

SOLUTION

True.

Reason: The Code of conduct is measure adopted by the Election Commission to ensure free and fair elections in India. It explains the rules that are to be followed by the Government, political parties and voters, before elections and during elections. Violation of the Code of Conduct can lead to termination of candidature or even imprisonment.

Under special circumstances the Election Commission holds re-elections in a particular constituency for a second time.

SOLUTION

True.

Under special circumstances the

Election Commission holds re-elections in a particular constituency for a second time. It is done in case of any dispute arising regarding the election for e.g. complaints criminal malpractices like booth capturing and in special circumstances of high NOTA votes.

The state government decides as to when and in how many stages the elections would be held in a particular State.

SOLUTION

False.

The Election Commission decides as to when and in how many stages the elections would be held in a particular State. It is the sole authority on conducting elections in Indian.


Write short note.

Journey from the ballot box to EVM machine

SOLUTION

Since the first General Election in 1951-52, the election process has undergone various changes to improve voter experience. One such change includes introduction of Electronic Voting Machine (EVM) in 1990s. It was a step towards preservation of environment since the machine eliminated the use of paper, it was now easier to vote for disabled people and promised an early declaration of results. The most notable feature of the EVM, however, was the NOTA (None of the above) option which enabled the voters to not vote for any candidate if they were not satisfied with him/her.

Reorganising the constituencies

SOLUTION

Reorganisation of the constituencies is the responsibility of the Delimitation committee of the Election Commission. The constituencies are reorganized from time to time on the basis of population density of an area, as tabulated in the decennial census reports. Uttar Pradesh is the most densely populated state of India, and hence has the largest no. of seats to Loksabha in the general election, each seat representing a constituency. At present there are 543 constituencies which are due for a reorganisation in 2021 on the basis of the next Census report.

Complete the following picture.

SOLUTION

Role of Election Commission: Conduct free and fair elections in the country.

Role of the voters: Cast their votes and participate in the election process

Role of political parties & their candidates: Follow the Code of Conduct.

Answer in brief. 

Explain the functions of the Election Commission

SOLUTION

The functions of the Election Commission are as follows:

1. Prepare voters list

It is responsible to preparing a list of eligible voters and updating existing voter’s list. It has the sole authority to issue voter identity cards.

2. Formulate the timetable and programme of elections.

It is responsible for conducting free and fair elections and decides when to conduct elections and how to conduct elections in every state.

3. Scrutinize candidate applications.

Every candidate, affiliated to a party or standing independent, has to fill an application with the election commission giving information about oneself. The commission then scrutinizes all the applications and allows the eligible candidates to contest.

4. Recognize political parties.

All political parties are required to be recognized by the Election commission. The commission has the right to derecognize a party as well. It is also responsible for allotting election symbols to the political parties.

5. Resolve disputes relating to elections.

The commission is responsible for resolution of any dispute arising regarding elections. It can accordingly declare any candidate disqualified and call for re-election in a constituency.

Write some additional information about post of the Election Commissioner.

SOLUTION

The Election Commissioner is an important office in the Government of India.

1. He is appointed by the President and is responsible for the smooth conduct of the election process. The Election Commissioner are mostly retired IAS officers appointed on an extended term.

2. At first there was just one Election Commissioner, later in 1989 the Commission was enlarged with a Chief Election Commissioner and two Election commissioners.

3. Sukumar Sen was the first Chief Election Commissioner of India and Om Prakash Rawat is the current Chief Election Commissioner.

4. The term of the Election Commissioner is for 6 years, draws salary at par with those of the Judges the Supreme Court of India.

5. The Commissioner can only be removed from office with two-thirds majority in Loksabha and Rajsabha on the grounds of misconduct or incapacity.

Explain the meaning of Code of Conduct

SOLUTION

Some important points on the Code of Conduct are:

1. Code of Conduct is a measure adopted by the Election Commission of India to ensure free and fair elections. It is use to control incidences of malpractices during the elections.

2. It is a set of guidelines for the Government, political parties and candidates to be followed before and during the elections.

3. It concerns rules and regulations with respect to speeches, election manifestos, processions and general conduct.

4. Its objective is to check misuse of power during the elections and curb malpractices e.g. hate speeches, liquor distribution, use of muscle force etc. Violation of the code of conduct can lead to cancellation of candidature.

5. Due to the strict observance of the code in the last few elections, the people have become more confident and aware of their rights and duties as voters during the election process.

Organise a mock poll in the school to understand the process of voting .

SOLUTION

Our school witness election every academic year. This year, as the election process was a part of the study, we decided to strictly observe the election processes. The details of the observation are given below:

1. Formation of school squads (which can be related to Formation of Constituencies):

• There were 4 squads namely blue, red, green and pink. It resembled the constituencies in national and state-level elections.

2. Filling of Nominations:

• The nomination of candidates is an important part of the election process.

• The regulations require that the candidate or the person who suggests his name files the nomination papers with the principal (Returning Officer in general election)

• Criteria were set for the qualification of those who become candidates.

3. Scrutiny of Nominations:

• The principal (Returning Officer) scrutinizes the nomination papers very carefully.

• If the eligibility of the student candidate is dissatisfied, he/she is officially stopped from contesting in the election.

• The candidates could withdraw their nomination papers till the prescribed period.

• The security deposit from candidates done in the general elections was not possible in the case of a school election. This step was omitted here.

4. Election Campaign:

Techniques of the election campaign and the tools employed by the squads and the independent candidates are many:

• Election Manifesto

• Electioneering (Activities and Techniques to Persuade Voters)

• Canvassing

• Meet the candidate event

• Class-to-class campaigning

In general elections, the candidates are assigned the tasks like:

• to address public meetings

• street corner meetings

• door-to-door canvassing

• new slogans are coined to attract the masses

• advertisements are released to the press (the popular daily and weekly newspapers)

• Radio and the Television are used to broadcast the speeches and panel-discussions of leaders of various parties

• electronic media plays the most effective role in creating people’s awareness of programs of the political parties

• Attend many interviews to newspapers and television agencies.

• Wide coverage is being given to all these events at regular intervals

5. Polling Personnel and the Polling:

• The election campaign was stopped 48 hours before the time when the poll concludes on the polling day.

• The vice-principal (Presiding Officer) manages the whole of the polling process and guarantee that all persons working under him adhere to the electoral norms and practices.

• The voter records his vote by placing the seal-mark against the name of the candidate he wants to vote. (in general election it is by pressing the button of the voting machine).

6. Counting of Votes and Declaration of Results:

• After the polling has ended the ballot boxes or the voting machines are sealed and carried under custody to the counting stations (concerned classrooms).

• Then the process of counting the votes began.

• The representatives of all the squads were present at the counting point.

• The candidate who obtains the highest number of votes is declared elected.

7. Submission of Account Relating to Election Expenses:

• The school budget law fixes the maximum limit of the expenses to be incurred by various proceedings on their election.

• In general election in India, the limit of election expenses for an Assembly election in most States was raised from Rs. 1.50 lakh to Rs. 6 lakh.

• It was enhanced from Rs. 4.50 lakh to Rs. 15 lakh for a Parliamentary contest.

• The candidates are required to file an account of the election expenses.

• It is a dishonest practice for a candidate to expend more money than the prescribed amount on his election.

• These steps were not present or required in the school election.

8. Election Disputes:

• The concerned teachers and the administrative head formed the election dispute cell in school.

• The Indian Constitution originally provided for the appointment of Election Tribunals for deciding disputes happening in connection with elections.

• The Nineteenth Amendment Act (1966) eliminated this provision and insisted that the election disputes would be decided by the High Courts.

Thus the scrutiny and recording of school election gave us a better understanding of the National election in India.


Balbharati, solutions, for, Social, Science, History, and, Civics, 10th, Standard, SSC, Maharashtra, State, Board, chapter 1, Working of the Constitution, [Latest edition],

Exercise | Q 1.1 | Page 74

Choose the correct option from the given options and complete the sentence. 

In Maharashtra __________ seats are reserved for women in local  self-governing institutions. 

25%

30%

40%

50%

Solution

50%

Which of the following laws created a favorable environment for women to secure freedom and self-development? 

Options

Right to Information Act 

Dowry Prohibition Act 

Food Security Act 

 None of the above

Solution

The Dowry Prohibition Act

The essence of democracy is ________

universal adult franchise. 

decentralisation of power. 

policy of reservation of seats. 

judicial decisions.

Solution

decentralisation of power.

Exercise | Q 1 | Page 74

State whether following statement is true or false. Give reason for your answer. 

Indian democracy is considered the largest democracy in the world.

Solution

True

Reason : Indian democracy is considered the largest democracy in the world because of political maturity. It’s the world’s second largest country in terms of population, people have direct representation in the legislative processes through regular elections and the right to adult suffrage.

Secrecy in the working of Government has increased due to the Right to Information.

Solution

False

Reason: Secrecy in the working of Government has decreased due to the Right to Information (Act 2005). Since 2000, the democratic reforms has been approached as ‘rights’ of citizen which has made governance more transparent and the government more accountable.

The nature of Constitution is seen as a living document.

Solution

True.

Reason: The Constitution is seen as a living document owing to its dynamic nature. It has to change according to changing conditions of the society and the Parliament has been entrusted with that responsibility.

Exercise | Q 1 | Page 74

Write short note.

Provisions regarding minorities.

Solution

The constitution has made several provisions for the protection of minorities in the country. It prohibits discrimination on the basis of caste, religion, race, language and region. Comprehensive provisions in the Fundamental Rights protect their right to equality, right against exploitation, and their cultural and educational rights.

Policy of reservation of seats.

Solution

Policy of reservation of seats is meant for the weaker section of the society who have been deprived of equal opportunity to education and employment for years. The Constitution accordingly mandates reservation of seats for scheduled caste, scheduled tribes and other backward classes in educational institutions and government services.

Women representation in the Loksabha.

Solution

Since independence, steps have been to address the issue of inadequate representation of women in political institutions. Under the 73rd and 74th amendment to the Constitution, 33% of seats in the local self- governing institutions are reserved for women. The representation of women in Lok Sabha has also seen a significant improvement with appointment of 12.15% women MPs in 2014 General elections.

Exercise | Q 1 | Page 74

Explain the following concept.

Right based approach

Solution

Since 2000, the approach towards democratic reform has evolved to be right based. Democratic reforms are necessitated as the ‘rights’ of the citizen, instead of approached as a part of the Directive principle of State policy. Citizens can take the government to the court in case their ‘rights’ are not met and thus, this change in approach has strengthened our democracy and made the govt. more accountable to the public. People now have the Right to Information, Right to Food, Right to Education and thus are more participative in the democratic processes.

Right to information

Solution

Right to information was enacted in 2005 to empower the citizen with vital information about the working and decision making process of the state. It makes the govt. more accountable and transparent, with increasing communication between the state and the citizen, hence building trust. It has reduced the element of secrecy in the working of government. The movement for RTI was first started in the state of Maharashtra in 2000 under the leadership of Anna Hazare. After the success of the state level efforts, the movement acquired national importance later in 2005.

Exercise | Q 1 | Page 74

Answer the following question.

What are the effects of reducing the voting age from 21 years to 18 years ?

Solution

The effects of reducing the voting age from 21 years to 18 years are:

1. Increased participation in the political processes. India has the largest number of voters compared to any other democratic country.

2. It encourages youth participation in public life, giving the younger generation an opportunity to be the change makers.

3. The change is not just quantitative but qualitative as well since new parties are emerging with the active support of the young voters.

4. It reflects the political maturity of India that empowers and actively working towards helping its citizens exercise their Right to vote.

5. Such provisions have made India the largest democracy in the world.

What is meant by establishment of social justice?

Solution

Social justice and equality are important objectives of our Constitution. It means establishing and ensuring a fair environment for the growth of every individual without any form of discrimination. Various provisions have been made to establish social justice in our society, some of these are:

Policy of Reservation: Seats are reserved for the weaker section of the society to enable them equal and fair opportunities for education and government services.

Scheduled Castes and Tribes (Prevention of Atrocities) Act: It prevents any act of injustice and atrocities committed against the people belonging to Scheduled Castes and Scheduled Tribes.

Provisions for Minority: There is a comprehensive provision in the Constitution that protects the fundamental rights of the minority to equality, freedom, education, right against exploitation, and the right to preserve their culture.

Laws for Women: Taking into account the problems of women, various policies have been formulated to remove illiteracy among women and avail them of equal opportunity for their development. The right to have an equal share in the property of their father and husband, the Dowry Prohibition Act, the Domestic Violence Prohibition Act, etc. have been conceptualized to create a favourable environment for women.

Which decision of the Court has resulted in protection of honour and dignity of women ?

Solution

The decision of the court in the cases of domestic violence, sexual harassment in work place etc. has resulted in protection of honour and dignity of women.

The most recent case in news had been the matter of Triple Talaq, where the practice was declared as unconstitutional as per the decision of the Supreme Court. It was an unfair practice subjected against Muslim women where divorce was pronounced with mere utterance of the word ‘Talaq’ trice on most trivial of issues with no formal legal proceedings, thus undermining various fundamental rights of women. It violated their dignity and fundamental right against discrimination on the basis of religion and gender.

Supreme Court as the apex judicial body is responsible for ensuring the preservation of the fundamental rights. Important judgments by the judiciary on various subjects have made the fundamental rights in the constitution more meaningful.

Project | Q 1 | Page 74

Which information can be secured with the help of right to information? Find out with the help of your teachers.

Solution

Under the provisions of the Act, Right to Information (RTI) is an act of the Parliament of India any citizen of India may ask for information from a “public authority” (a body of Government or “instrumentality of State”) which is necessary to reply immediately or within thirty days.

The Right to information in India is governed by two major bodies:

• Central Information Commission (CIC)

• State Information Commissions

The information which can be collected are:

1) Information from a public authority

2) Inspection of work, records etc of public authority

3) Details related to members of parliament and members of legislative assembly.

The important feature of RTI is that it is applicable to Indian citizens, but not associations or companies.

Make a list of concessions given by the Government for the students of minority community ?

Solution

AREA    SCHEMES

Educational   

1.Scholarship Schemes

2.Maulana Azad National Fellowship (MANF)

3.Padho Pardesh – Scheme of Internet Subsidy on Educational Loans for Overseas Studies for the Students Belonging to the Minority Communities

4.Naya Savera – Free Coaching and Allied Scheme

5.Nai Udaan – Support for Students for preparation of main Examination who clear Prelims conducted by UPSC/SSC , state public service commission (PSC) etc . 

Economic   

1.Seekho Aur Kamao (Learn & Earn)

2.USTTAD (Upgrading the skills and Training in Traditional Arts/Crafts for Development)

3.Nai Manzil

4.Concessional credit through National Minorities Dvelopment and Finance Corporation (NMDFC)

Infrastructural assistance    1.Pradhan Mantri Jan Vikas Karyakram (PMJVK)

Visit the official website of National election commission and collect more information about it.

Solution

(INFORMATION FROM THE INTERNET)

The Election Commission of India is an autonomous constitutional authority responsible for administering Union and State election processes in India. The body administers elections to the Lok Sabha, Rajya Sabha, State Legislative Assemblies in India, and the offices of the President and Vice President in the country.

A Constitutional Body

Election Commission of India is a permanent Constitutional Body. The Election Commission was established in accordance with the Constitution on 25th January 1950. The Commission celebrated its Golden Jubilee in 2001.

Originally the commission had only a Chief Election Commissioner. It currently consists of Chief Election Commissioner and two Election Commissioners.

For the first time, two additional Commissioners were appointed on 16th October 1989 but they had a very short tenure till 1st January 1990. Later, on 1st October 1993 two additional Election Commissioners were appointed. The concept of multi-member Commission has been in operation since then, with decision making power by majority vote.

Appointment & Tenure of Commissioners

The President appoints Chief Election Commissioner and Election Commissioners. They have a tenure of six years, or up to the age of 65 years, whichever is earlier. They enjoy the same status and receive salary and perks as available to Judges of the Supreme Court of India. The Chief Election Commissioner can be removed from office only through impeachment by Parliament.

Transaction of Business

The Commission transacts its business by holding regular meetings and also by circulation of papers. All Election Commissioners have equal say in the decision making of the Commission. The Commission, from time to time, delegates some of its executive functions to its officers in its Secretariat.

The Setup

The Commission has a separate Secretariat at New Delhi, consisting of about 300 officials, in a hierarchical set up.

Budget & Expenditure

The Secretariat of the Commission has an independent budget, which is finalized directly in consultation between the Commission and the Finance Ministry of the Union Government. The latter generally accepts the recommendations of the Commission for its budgets. The major expenditure on the actual conduct of elections is, however, reflected in the budgets of the concerned constituent units of the Union – States and Union Territories.

Political Parties & the Commission

Political parties are registered with the Election Commission under the law. The Commission ensures inner-party democracy in their functioning by insisting upon them to hold their organizational elections at periodic intervals.

Advisory Jurisdiction & Quasi-Judicial Functions

Under the Constitution, the Commission also has advisory jurisdiction in the matter of post-election disqualification of sitting members of Parliament and State Legislatures

Judicial Review

The decisions of the Commission can be challenged in the High Court and the Supreme Court of India by appropriate petitions. By long-standing convention and several judicial pronouncements, once the actual process of elections has started, the judiciary does not intervene in the actual conduct of the polls.

Media Policy

The Commission has a comprehensive policy for the media. It holds regular briefings for the mass media-print and electronic, on a regular basis, at close intervals during the election period and on specific occasions as necessary on other occasions.

Voter Education

Voters’ Participation in the democratic and electoral processes is integral to the successful running of any democracy and the very basis of wholesome democratic elections. Recognizing this, Election Commission of India, in 2009, formally adopted Voter Education and Electoral participation as an integral part of its election management.

International Co-operation

India is a founding member of the International Institute for Democracy and Electoral Assistance (IDEA), Stockholm, Swed

Take an interview of women representations from local self-governing institutions from your area.

Solution

The MLA of our district is a woman. She has been in the socio-cultural activities in our region for the last fifteen years. She is vibrant and active. An interview with her was very insightful and motivating.

Q: Do you see women reservation as part of a greater change in the social system?

Ans. I judge the excellence and the ambiance of politics will improve if more women come in. After bearing in mind the structure work for 45 years, it is understandable that we are the weaker sex, whether we like it or not. We are barred from jobs, the economic mainstream, decision-making processes, heritage rights… Whether one is fighting for the Scheduled Castes, the Backward Classes, or the minorities…. the main group that is affected are women. And things have not changed since then. Unless we are assured an access point by law we will never be allowed to participate. I really consider that. Some women say that we should come into decision-making positions on our own stream, but how many have come so far? To all those who say that they will do it on their own, I would like to ask why is the number of seats occupied by women in the legislatures deteriorating?

Q: You have completed some individual efforts at getting many numbers of women party tickets. What have you found to be the barriers?

Ans. We have tried but we have been unproductive because we are neither in the collection panels nor are we represented in decision-making bodies. We give lists, we struggle, we counsel, but they don’t listen to us. The election commission will reserve 33 percent of the seats by ballot for women. These are reserved for women for two terms and are then rotated. In the interim, women can establish themselves and if they are popular they will be able to contest on their own worth as general candidates by the next elections. So each ward has a chance to throw up women. We can launch a deadline of 25 years, or five general elections, by which time the reservations for women could be remoted. If women do not have an entry tip, how will they ever get in?

Q: What is your individual stand on the subject of 33 percent reservation for women?

Ans. As a result of reservation, one million women have been elected to local bodies. In many states they have even surpassed the quota for example, in Karnataka, women constitute 47 percent of the elected panchayat members. Bengal has also been a triumph story, as have Maharashtra, Kerala and Tamil Nadu. We need reforms not just for women the whole system of selection of candidates needs to be renovated.

Q: How did this issue get included in your party’s manifesto?

Ans. We had argued for its early introduction so that negotiations and debate could be allowed. Finally, when it was introduced, those who had never spoken about reservation for Backward Classes suddenly become the champions of Backward Class reservations. Between 1991, when the Panchayath bill was introduced, until 1996 when this bill is on the edge of being introduced, these people did not coherent any of their concerns for the Backward Class men! The issue gains importance only now because women are about to gain seats.

Q: Do you think this is just party games or something else?

Ans. No, no, even women in our party stood up to oppose the bill. There is a lobby of self-interest amongst women as well. The matter is different among the patriarchal viewpoint. They ask; Once decisions are taken, why have a women’s meeting?

Q: What is the status now?

Ans. A Select Committee has been set up. I am not recommending anything. Based on the various Commission reports we made reservations on the services. Nobody had spoken about proviso for Backward Classes or others in Parliament or legislatures. Women cut across all sections and by giving reservations to them you will be serving women from all sections to come forward. There are presently no reserved constituencies for the Backward Classes and minorities, so why should this issue get tied up with a reservation for women?

The interview session was so encouraging, and the MLA winded up the conversation by laying high remarks about the future of the whole society.


Samacheer, Kalvi, 10th, sslc, Science, Solutions, Chapter 6, Nuclear Physics, tamilnadu board, Physics,

Question 1.
Identify A, B, C, and D from the following nuclear reactions.

Solution:


Samacheer Kalvi 10th Science Solutions Chapter 6 Nuclear Physics 2

A is alpha particle, B is neutron, C is proton and D is electron.

Question 2.
A radon specimen emits radiation of 3.7 × 103 GBq per second. Convert this disintegration in terms of a curie, (one curie = 3.7 × 1010 disintegration per second)
Solution:
1 Bq = one disintegration per second
one curie = 3.7 × 1010 Bq

Question 3.
92U235 experiences one α – decay and one β – decay. Find the number of neutrons in the final daughter nucleus that is formed.
Solution:
Let X and Y be the resulting nucleus after the emission of the alpha and beta particles respectively.

Number of neutrons = Mass number – Atomic number = 231 – 91 = 140.

Question 4.
Calculate, the amount of energy released when a radioactive substance undergoes fusion and results in a mass defect of 2 kg.
Solution:
Mass defect in the reaction (m) = 2 kg
Velocity of light (c) = 3 × 108 ms-1
By Einstein’s equation,
Energy released E = mc2
= 2 × (3 × 108)2
= 1.8 × 1017 J.

Samacheer Kalvi 10th Science Nuclear Physics Textual Evaluation

I. Choose the correct answer

Question 1.
Man – made radioactivity is also known as _____.
(a) Induced radioactivity
(b) Spontaneous radioactivity
(c) Artificial radioactivity
(d) (a) & (c).
Answer:
(d) (a) & (c).

Question 2.
Unit of radioactivity is:
(a) roentgen
(b) curie
(c) becquerel
(d) all the above
Answer:
(d) all the above

Question 3.
Artificial radioactivity was discovered by _____.
(a) Becquerel
(b) Irene Curie
(c) Roentgen
(d) Neils Bohr.
Answer:
(b) Irene Curie

Question 4.
In which of the following, no change in mass number of the daughter nuclei takes place:
(i) a decay;
(ii) P decay
(iii) y decay
(iv) neutron decay
(a) (i) is correct
(b) (ii) and (iii) are correct
(c) (i) and (iv) are correct
(d) (ii) and (iv) are correct
Answer:
(b) (ii) and (iii) are correct

Question 5.
_____ isotope is used for the treatment of cancer.
(a) Radio Iodine
(b) Radio Cobalt
(c) Radio Carbon
(d) Radio Nickel.
Answer:
(b) Radio Cobalt

Question 6.
Gamma radiations are dangerous because:
(a) it affects eyes and bones
(b) it affects tissues
(c) it produces genetic disorder
(d) it produces an enormous amount of heat
Answer:
(c) it produces genetic disorder

Question 7.
_____ aprons are used to protect us from gamma radiations.
(a) Lead oxide
(b) Iron
(c) Lead
(d) Aluminium.
Answer:
(c) Lead

Question 8.
Which of the following statements is / are correct?
(i) α particles are photons
(ii) Penetrating power of γ radiation is very low
(iii) Ionization power is maximum for α rays
(iv) Penetrating power of γ radiation is very high
(a) (i) & (ii) are correct
(b) (ii) & (iii) are correct
(c) (iv) only correct
(d) (iii) & (iv) are correct.
Answer:
(d) (iii) & (iv) are correct.

Question 9.
Proton-Proton chain reaction is an example of:
(a) Nuclear fission
(b) α – decay
(c) Nuclear fusion
(d) β – decay
Answer:
(c) Nuclear fusion

Question 10.
In the nuclear reaction X126⟶α decay zYA, the value of A & Z.
(a) 8, 6
(b) 8, 4
(c) 4, 8
(d) cannot be determined with the given data.
Answer:
(c) 4, 8

Question 11.
Kamini reactor is located at _____.
(a) Kalpakkam
(b) Koodankulam
(c) Mumbai
(d) Rajasthan.
Answer:
(a) Kalpakkam

Question 12.
Which of the following is/are correct?
(i) Chain reaction takes place in a nuclear reactor and an atomic bomb.
(ii) The chain reaction in a nuclear reactor is controlled.
(iii) The chain reaction in a nuclear reactor is not controlled.
(iv) No chain reaction takes place in an atom bomb.
(a) (i) only correct
(b) (i) & (ii) are correct
(c) (iv) only correct
(d) (iii) & (iv) are correct
Answer:
(b) (i) & (ii) are correct

II. Fill in the blanks

Question 1.
One roentgen is equal to ______ disintegrations per second?
Answer:
3.7 × 1010.

Question 2.
Positron is an _____.
Answer:
antiparticle of electron.

Question 3.
Anaemia can be cured by _____ isotope.
Answer:
Radio iron (Fe59).

Question 4.
Abbreviation of ICRP _____.
Answer:
International Commission on Radiological Protection.

Question 5.
_____ is used to measure the exposure rate of radiation in humans.
Answer:
Roentgen.

Question 6.
_____ has the greatest penetration power.
Answer:
Gamma ray.

Question 7.
zYA→Z+1YA+X; Then X is _____.
Answer:
−1e0 (β decay).

Question 8.
zXA→YAZ This reaction is possible in _____ decay.
Answer:
Gamma (γ).

Question 9.
The average energy released in each fusion reaction is about _____ J.
Answer:
3.84 × 10-12.

Question 10.
Nuclear fusion is possible only at an extremely high temperature of the order of _____ K.
Answer:
107 to 109.

Question 11.
The radioisotope of _____ helps to increase the productivity of crops.
Answer:
phosphorous (P – 32).

Question 12.
If radiation exposure is 100 R, it may cause _____.
Answer:
fatal disease.

III. State whether the following statements are true or false: If false, correct the statement

Question 1.
Plutonium -239 is a fissionable material.
Answer:
True.

Question 2.
Elements having an atomic number greater than 83 can undergo nuclear fusion.
Answer:
False.
Correct Statement: Elements having an atomic number greater than 83 can undergo nuclear fusion.

Question 3.
Nuclear fusion is more dangerous than nuclear fission.
Answer:
False.
Correct Statement: Nuclear fission is more dangerous than nuclear fusion. Because the average energy released in fission (3.2 × 10-11 J) process is more than the average energy released in fusion (3.84 × 10-12 J).

Question 4.
Natural uranium U-238 is the core fuel used in a nuclear reactor.
Answer:
False.
Correct Statement: U-238 is not a fissile material but are abundant in nature. But in a reactor, this can be converted into a fissile material Pu239 and U233. Only fissile materials are used in the fuel of a nuclear reactor.

Question 5.
If a moderator is not present, then a nuclear reactor will behave like an atom bomb.
Answer:
True.

Question 6.
During one nuclear fission on an average, 2 to 3 neutrons are produced.
Answer:
True.

Question 7.
Einstein’s theory of mass-energy equivalence is used in nuclear fission and fusion.
Answer:
True.

IV. Match the following

Question 1.

1. BARC(a) Kalpakkam
2. India’s first atomic power station(b) Apsara
3. IGCAR(c) Mumbai
4. The first nuclear reactor in India(d) Tarapur

Answer:
1. (c) Mumbai
2. (d) Tarapur
3. (a) Kalpakkam
4. (b) Apsara

Question 2.

1. Fuel(a) lead
2. Moderator(b) heavy water
3. Coolant(c) Graphite
4. Shield(d) Uranium

Answer:
1. (d) uranium
2. (c) Graphite
3. (b) heavy water
4. (a) lead

Question 3.

1. Soddy Fagan(a) Natural radioactivity
2. Irene Curie(b) Displacement law
3. Henry Becquerel(c) Mass energy equivalence
4. Albert Einstein(d) Artificial Radioactivity

Answer:
1. (b) Displacement law
2. (d) Artificial Radioactivity
3. (a) Natural radioactivity
4. (c) Mass energy equivalence

Question 4.

1. Uncontrolled fission Reaction(a) Hydrogen Bomb
2. Fertile material(b) Nuclear Reactor
3. Controlled fission Reaction(c) Breeder reactor
4. Fusion reaction(d) Atom bomb

Answer:
1. (d) Atom bomb
2. (c) Breeder reactor
3. (b) Nuclear Reactor
4. (a) Hydrogen Bomb

Question 5.

1. Co – 60(a) Age of fossil
2. I – 13(b) Function of Heart
3. Na – 24(c) Leukaemia
4. C – 14(d) Thyroid disease

Answer:
1. (c) Leukemia
2. (d) Thyroid disease
3. (b) Function of Heart
4. (a) Age of fossil

V. Arrange the following in the correct sequence

Question 1.
Arrange in descending order, on the basis of their penetration power.

  1. Alpha rays
  2. Beta rays
  3. Gamma rays
  4. Cosmic rays.

Answer:

  1. Gamma rays
  2. Beta rays
  3. Alpha rays
  4. Cosmic rays.

Question 2.
Arrange the following in the chronological order of discovery.

  1. A nuclear reactor
  2. Radioactivity
  3. Artificial radioactivity
  4. Discovery of radium.

Answer:

  1. Radioactivity (1896)
  2. Discovery of radium (1898)
  3. Artificial radioactivity (1934)
  4. Nuclear reactor (1942).

VI. Use the analogy to fill in the blank

Question 1.
Spontaneous process : Natural Radioactivity, Induced process: _____.
Answer:
Artificial radioactivity
(or)
Man – made activity.

Question 2.
Nuclear Fusion : Extreme temperature, Nuclear Fission: _____.
Answer:
Room temperature.

Question 3.
Increasing crops : Radio phosphorous, Effective functioning of heart: _____.
Answer:
Radio sodium (Na24).

Question 4.
Deflected by electric field : α ray, Null Deflection: _____.
Answer:
γ ray (Gamma – ray).

VII. Numerical Problems

Question 1.
88Ra226 experiences three α-decay. Find the number of neutrons in the daughter element.
Solution:
88Ra226 consider as a parent element that is 88X226 and their daughter element is zYA
According to α decay process,
88X26⟶3α decay 82214+3α decay
During the 3α decay, the atomic number decreases by 6 and mass number decreases by 12.
So the number of neutrons in the daughter element
N = A – Z
N = 214 – 88 = 126
Number of neutrons in the daughter element N = 126.

Question 2.
A cobalt specimen emits induced radiation of 75.6 millicurie per second. Convert this disintegration in to becquerel (one curie = 3.7 × 1010 Bq).
Solution:
Cobalt specimen emits induced radiation = 75.6 millicurie per second
(1 curie = 3.7 × 1010 Bq)
So 75.6 millicurie = 75.6 × 103 × 1 curie
= 75.6 × 10-3 × 3.7 × 1010 Bq
= 279.72 × 107
= 2.7972 × 109 Bq
75.6 millicurie per second is equivalent to 2.7972 × 109 Bq.

VIII. Assertion and Reason Type Questions

Mark the correct choice as
(a) If both the assertion and the reason are true and the reason is the correct explanation of the assertion.
(b) If both the assertion and the reason are true, but the reason is not the correct explanation of the assertion.
(c) Assertion is true, but the reason is false.
(d) Assertion is false, but the reason is true.

Question 1.
Assertion: A neutron impinging on U235, splits it to produce Barium and Krypton.
Reason: U-235 is a fissile material.
Answer:
(a) If both the assertion and the reason are true and the reason is the correct explanation of the assertion.

Question 2.
Assertion: In a β – decay, the neutron number decreases by one.
Reason: In β – decay atomic number increases by one.
Answer:
(d) The assertion is false, but the reason is true.
Explanation: In β – decay there is no change in the mass number of the daughter nucleus but the atomic number increases by one.

Question 3.
Assertion: Extreme temperature is necessary to execute nuclear fusion.
Reason: In nuclear fusion, the nuclei of the reactants combine releasing high energy.
Answer:
(a) If both the assertion and the reason are true and the reason is the correct explanation of the assertion.

Question 4.
Assertion: Control rods are known as ‘Neutron seeking rods’
Reason: Control rods are used to perform a sustained nuclear fission reaction.
Answer:
(a) If both the assertion and the reason are true and the reason is the correct explanation of the assertion.
Explanation: Control rods are used to control the number of neutrons in order to have a sustained the chain reaction. They absorb the neutrons, (they seeking the neutrons)

IX. Answer in one or two words (VSA)

Question 1.
Who discovered natural radioactivity?
Answer:
Henri Becquerel was discovered natural radioactivity.

Question 2.
Which radioactive material is present in the ore of pitchblende?
Answer:
Uranium

Question 3.
Write any two elements which are used for inducing radioactivity?
Answer:

  1. Boron and Aluminium.
  2. Alpha particle and neutron.

Question 4.
Write the name of the electromagnetic radiation which is emitted during a natural radioactivity.
Answer:
Gamma rays

Question 5.
If A is a radioactive element which emits an α-particle and produces 104Rf259. Write the atomic number and mass number of the element A.
Answer:
In α decay
zXAα decay 263×z−2YA−4+2He4(α decay )106X263⟶α decay 104Rf259+2He4
In element A having atomic number is 106 and mass number is 263.

Question 6.
What is the average energy released from a single fission process?
Answer:
The average energy released from a single fission process is about 3.2 × 10-11 J.

Question 7.
Which hazardous radiation is the cause for the genetic disorders (or) effect?
Answer:
Radioactive radiations

Question 8.
What is the amount of radiation that may cause the death of a person when exposed to it?
Answer:
When the body is exposed to about 600 R, it leads to death.

Question 9.
When and where was the first nuclear reactor built?
Answer:
The first nuclear reactor was built in 1942 in Chicago, USA.

Question 10.
Give the SI unit of radioactivity.
Answer:
Becquerel

Question 11.
Which material protects us from radiation?
Answer:
Lead coated aprons and lead gloves should be used while working with the hazardous area. These materials are used to protects us from radiation.

X. Answer the following questions in a few sentences.

Question 1.
Write any three features of natural and artificial radioactivity.
Answer:

Natural radioactivityArtificial radioactivity
1. Emission of radiation due to the self-disintegration of a nucleus.1. Emission of radiation due to the disintegration of a nucleus through the induced process.
2. Alpha, Beta and Gamma radiations are emitted.2. Mostly elementary particles such as neutron, positron, etc. are emitted.
3. It is a spontaneous process.3. It is an induced process.

Question 2.
Define critical mass.
Answer:
The minimum mass of fissile material necessary to sustain the chain reaction is called ‘critical mass (mc). It depends on the nature, density and the size of the fissile material.

Question 3.
Define One roentgen.
Answer:
One roentgen is defined as the quantity of radioactive substance which produces a charge of 2.58 × 10-4 coulomb in 1 kg of air under standard conditions of pressure, temperature and humidity.

Question 4.
State Soddy and Fagan’s displacement law.
Answer:
During a radioactive disintegration, the nucleus which undergoes disintegration is called a parent nucleus and that which remains after the disintegration is called the daughter nucleus.

Question 5.
Give the function of control rods in a nuclear reactor.
Answer:
Control rods are used to control the number of neutrons in order to have sustained chain reaction. Mostly boron or cadmium rods are used as control rods. They absorb the neutrons.

Question 6.
In Japan, some of the newborn children are having congenital diseases. Why?
Answer:
During the Second World War American, a bomber dropped the nuclear weapons over the Japanese cities of Hiroshima and Nagasaki. In the explosion of the atomic bomb to release the high energy dangerous radiation. In the explosion period, Japanese peoples are affected by radiation. This is the reason in Japan, some of the newborn children are having congenital diseases.

Question 7.
Mr Ramu is working as an X – ray technician in a hospital. But, he does not Wear the lead aprons. What suggestion will you give to Mr Ramu?
Answer:
X – rays have a destructive effect on living tissue. When the human body is exposed to X – rays, it causes redness of the skin, sores and serious injuries to the tissues and glands. They destroy the white corpuscles of the blood. If you don’t wear the lead aprons these kinds of diseases formed in your body. In my suggestion, you must wear lead aprons.

Question 8.
What is stellar energy?
Answer:
Fusion reaction that takes place in the cores of the Sun and other stars results in an enormous amount of energy, which is called as stellar energy.

Question 9.
Give any two uses of radioisotopes in the field of agriculture?
Answer:

  • The radioisotope of phosphorus (P – 32) helps to increase the productivity of crops.
  • The radiations from the radioisotopes can be used to kill the insects and parasites and prevent the wastage of agricultural products.

XI. Answer the following questions in detail.

Question 1.
Explain the process of controlled and uncontrolled chain reactions.
Answer:
(a) Controlled chain reaction

  • In the controlled chain reaction, the number of neutrons released is maintained to be one. This is achieved by absorbing the extra neutrons with a neutron absorber leaving only one neutron to produce further fission.
  • Thus, the reaction is sustained in a controlled manner. The energy released due to a controlled chain reaction can be utilized for constructive purposes.
  • The controlled chain reaction is used in a nuclear reactor to produce energy in a sustained and controlled manner.

(b) Uncontrolled chain reaction:

Question 2.
Compare the properties of Alpha, Beta and Gamma radiations.
Answer:

Propertiesα raysβ raysγ rays
What are they?Helium nucleus (2He4)consisting of two protons and two neutrons.They are electrons (−1e0), basic elementary particle in all atoms.They are electromagnetic waves consisting of photons.
ChargePositively charged particles. Charge of each alpha particle = +2eNegatively charged particles. Charge of each beta particle = -eNeutral particles. Charge of each gamma particle = zero
Ionising Power100 time greater than β rays and 10,000 times greater than γ raysComparatively lowVery less ionization power
Penetrating powerLow penetrating power (even stopped by a thick paper)Penetrating power is greater than that of α rays. They can penetrate through a thin metal foil.They have a very high penetrating power greater than that of β rays. They can penetrate through thick metal blocks.
Effect of an electric and magnetic fieldDeflected by both the fields. (in accordance with Fleming’s left-hand rule)Deflected by both the fields, but the direction of deflection is opposite to that for alpha rays. (in accordance with Fleming’s left-hand rule)They are not deflected by both the fields.
SpeedTheir speed ranges from 1/10 to 1/20 times the speed of light.Their speed can go up to 9/10 times the speed of light.They travel with the speed of light.

Question 3.
What is a nuclear reactor? Explain its essential parts with their functions.
Answer:
Nuclear reactor: A Nuclear reactor is a device in which the nuclear fission reaction takes place in a self – sustained and controlled manner to produce electricity.

Components of a Nuclear Reactor:
The essential components of a nuclear reactor are

  • Fuel: A fissile material is used as the fuel. The commonly used fuel material is uranium.
  • Moderator: A moderator is used to slow down the high energy neutrons to provide slow neutrons. Graphite and heavy water are commonly used moderators.
  • Control rod: Control rods are used to control the number of neutrons in order to have a sustained a chain reaction. Mostly boron or cadmium rods are used as control rods. They absorb the neutrons.
  • Coolant: A coolant is used to remove the heat produced in the reactor core, to produce steam. This steam is used to run a turbine in order to produce electricity. Water, air and helium are some of the coolants.
  • Protection wall: A thick concrete lead wall is built around the nuclear reactor in order to prevent the harmful radiations from escaping into the environment.

XII. HOT Questions

Question 1.
Mass number of a radioactive element is 232 and its atomic number is 90. When this element undergoes certain nuclear reactions, it transforms into an isotope of lead with a mass number 208 and an atomic number 82. Determine the number of alpha and beta decay that can occur.
Answer:
Mass number A = 232
Atomic number Z = 90
Daughter element:
Mass number A = 208
Atomic number Z = 82
Difference in mass number = 232 – 208 = 24
Difference in atomic number
= 90 – 82 = 8
Atomic number of α = 2
Atomic number of β = -1
Mass number of α = 4
Mass number of β = 0
Difference in mass number in transformations
= 24
Number of a decays = 244 = 6
Difference in atomic number = 8
ΔZ = 6α + 4β
= 6(2) + 4(-1)
= 12 – 4
= 8
∴ Number of β decays = 4
∴ Number of α decays = 6
∴ Number of β decays = 4

Question 2.
‘X – rays should not be taken often’. Give the reason.
Answer:

  • Radiation does involve in X – rays tests and isotope scans (in nuclear medicine) are too low to cause immediate hazardous effects.
  • If should be taken often, X – ray radiation from medical examinations though slightly increases one’s risk for cancer which can occur year or decades after X-ray exposure.

Question 3.
Cell phone towers should be placed far away from the residential area. why?
Answer:

  1. Living near a cell phone tower is not healthy. There is multiple health risks associated with living near a cell phone tower.
  2. Cell phone towers communicate by use pulsed microwave signals (radiofrequency radiation) with each other.
  3. That is the reason cell phone towers should be placed far away from the residential area.

Samacheer Kalvi 10th Science Nuclear Physics Additional Questions

I. Choose the best Answer.

Question 1.
Radium was discovered by _____.
(a) Marie curie
(b) Irene curie
(c) Henri Becquerel
(d) F. Joliot.
Answer:
(a) Marie Curie

Question 2.
How many radioactive substances discovered so far?
(a) 83
(b) 92
(c) 43
(d) 29
Answer:
(d) 29

Question 3.
The SI unit of Radioactivity is _____.
(a) Curie
(b) Rutherford
(c) Becquerel
(d) Roentgen (R).
Answer:
(c) Becquerel

Question 4.
Radioactivity is _____.
(a) increases with increase in temperature
(b) increases with increase in pressure
(c) depends on the number of electrons
(d) purely a nuclear phenomenon.
Answer:
(d) purely a nuclear phenomenon

Question 5.
Which of the following processes is a spontaneous process?
(a) Artifical radioactivity
(b) Natural radioactivity
(c) Photoelectric effect
(d) Collisions
Answer:
(b) Natural radioactivity

Question 6.
The charge of the β rays _____.
(a) 2e
(b) 0
(c) -e
(d) none of these.
Answer:
(c) -e

Question 7.
The charge of the γ rays _____.
(a) 2e
(b) 0
(c) -e
(d) none of these.
Answer:
(b) 0

Question 8.
The atomic number of the elements that exhibit artifical radioactivity is:
(a) more than 82
(b) more than 83
(c) less than 83
(d) less than 82
Answer:
(c) less than 83

Question 9.
Arrange α, β, γ rays in the increasing order of their ionizing power.
(a) α, β, γ
(b) β, α, γ
(c) γ, β, α
(d) γ, α, β.
Answer:
(c) γ, β, α

Question 10.
Which produces a charge of 2.58 × 10-4Coulomb in 1 Kg of air?
(a) Curie
(b) Becquerel
(c) Rutherford
(d) Roentgen
Answer:
(d) Roentgen

Question 11.
Ionising power of the γ rays _____.
(a) Comparatively very high ionization power
(b) 100 times greater than the α rays
(c) 100 times greater than the β rays
(d) Comparatively very less ionization power.
Answer:
(d) Comparatively very less ionization power.

Question 12.
Ionization power maximum for _____.
(a) neutrons
(b) α particles
(c) γ rays
(d) β particles.
Answer:
(b) α particles

Question 13.
Charge of gamma particle is:
(a) +2e
(b) -e
(c) Zero
(d) +1e
Answer:
(c) Zero

Question 14.
Which has low penetrating power?
(a) α rays
(b) γ rays
(c) β rays
(d) X rays.
Answer:
(a) α rays

Question 15.
In β – decay _____.
(a) atomic number decreases by one
(b) the mass number decreases by one
(c) proton number remains the same
(d) neutron number decreases by one.
Answer:
(d) neutron number decreases by one

Question 16.
In which decay the energy level of the nucleus changes:
(a) α – decay
(b) β – decay
(c) γ – decay
(d) neutron decay
Answer:
(c) γ – decay

Question 17.
In γ – decay _____.
(a) atomic number decreases by one
(b) there is no change in atomic and mass number
(c) energy only changes in the decay process
(d) both (b) and (c).
Answer:
(d) both (b) and (c).

Question 18.
The unit of decay constant is _____.
(a) no unit
(b) second
(c) second-1
(d) curie.
Answer:
(c) second-1

Question 19.
The range of temperature required for nuclear fusion is from:
(a) 107 to 109 K
(b) 10-9 to 10-7 K
(c) 105 to 109
(d) 105 to 107 K
Answer:
(a) 107 to 109 K

Question 20.
1 Rd is equal to _____.
(a) 106 decay / second
(b) 1 decay / second
(c) 3.7 × 1010 becquerel
(d) 1.6 × 1012 decay / second.
Answer:
(a) 106 decay / second

Question 21.
An element ZXA successively undergoes three α decays and four β decays and gets converted an element Y are respectively _____.
(a) Z−6YA−12
(b) Z+2YA−12
(c) Z−2YA−12
(d) Z−10YA−12.
Answer:
(c) Z−2YA−12

Question 22.
In the nuclear reaction 88Ra226 → X + 2He4X is:
(a) 90Th234
(b) 91Pa234
(c) 86Rn222
(d) 88Rn226
Answer:
(d) 88Rn226

Question 23.
Which one of the following is used in the treatment of skin diseases _____.
(a) Na24
(b) I31
(c) Fe59
(d) P32.
Answer:
(d) P32.

Question 24.
Anaemia can be diagnosed by _____.
(a) 15P31
(b) 15P32
(c) 26P59
(d) 11P24.
Answer:
(c) 26P59

Question 25.
Which is used as a coolant?
(a) Graphite
(b) Liquid sodium
(c) Boron
(d) Cadmium
Answer:
(b) Liquid sodium

Question 26.
The energy released per fission is _____.
(a) 220 MeV
(b) 300 MeV
(c) 250 MeV
(d) 200 MeV.
Answer:
(d) 200 MeV.

Question 27.
In the reaction 1N14 + 0n1 → X + 1H1 X is:
(a) 15P30
(b) 6C14
(c) 6C12
(d) 11Na23
Answer:
(c) 6C12

Question 28.
Natural uranium consists of _____.
(a) 99.72 % of U-238
(b) 0.28 % of U-238
(c) 0.72 % of U-238
(d) 99.28 % of U-238.
Answer:
(d) 99.28 % of U-238.

Question 29.
The number of power reactors in India is _____.
(a) 14
(b) 12
(c) 7
(d) 2.
Answer:
(a) 14

Question 30.
In the nucleus of 11Na23 the number of protons and neutrons are:
(a) 12, 11
(b) 10, 12
(c) 11, 12
(d) 11, 23
Answer:
(c) 11, 12

Question 31.
The moderator used in nuclear reactor is _____.
(a) cadmium
(b) boron carbide
(c) heavy water
(d) uranium (92U235).
Answer:
(c) heavy water

Question 32.
The first nuclear reactor was built at _____.
(a) Kalpakkam, India
(b) Hiroshima, Japan
(c) Chicago, USA
(d) Trombay, Bombay.
Answer:
(c) Chicago, USA

Question 33.
Which of the following is used in the treatment of skin cancer?
(a) Radio Cobalt
(b) Radio gold
(c) Radio Cobalt and radio gold
(d) none of the above
Answer:
(c) Radio Cobalt and radio gold

Question 34.
The explosion of an atom bomb is based on the principle of _____.
(a) uncontrolled fission reaction
(b) fusion reaction
(c) controlled fission reaction
(d) none of the above.
Answer:
(a) uncontrolled fission reaction

Question 35.
The reactor in which no moderator used is _____.
(a) fast breeder reactor
(b) pressurised water reactor
(c) pressurised heavy water reactor
(d) boiled water reactor.
Answer:
(a) fast breeder reactor

Question 36.
The number of neutrons present in 92U235is:
(a) 133
(b) 143
(c) 43
(d) 243
Answer:
(b) 143

Question 37.
In fast breeder, the coolant system used is _____.
(a) heavy water
(b) light water
(c) liquid sodium
(d) boiled water.
Answer:
(c) liquid sodium

Question 38.
The only reactor in the world which uses U-233 as fuel is _____.
(a) Zerlina
(b) Purnima
(c) Kamini
(d) Tires.
Answer:
(c) Kamini

Question 39.
The temperature of the interior of Sun is about _____.
(a) 1.4 × 107 K
(b) 108 K
(C) 14 × 107 K
(d) 600 K.
Answer:
(a) 1.4 × 107 K

Question 40.
Total energy radiated by Sun is about _____.
(a) 3.6 × 1028 Js-1
(b) 3.8 × 1028 Js-1
(c) 3.8 × 1026 Js-1
(d) 3.8 × 1023 Js-1.
Answer:
(c) 3.8 × 1026 Js-1


II. Fill in the blanks

Question 1.
Cathode rays are discovered by _____.
Answer:
J.J. Thomson.

Question 2.
Positive rays discovered by _____.
Answer:
Goldstein.

Question 3.
The chargeless particles are called neutron, it was discovered by _____.
Answer:
James Chadwick.

Question 4.
Ernest Rutherford explained that the mass of an atom is concentrated in its central part called _____.
Answer:
Nucleus.

Question 5.
The radioactive elements emit harmful radiations are ____, ____, ____ rays.
Answer:
alpha, beta, gamma.

Question 6.
_____ is an spontaneous process.
Answer:
Natural radioactivity.

Question 7.
The element whose atomic number is more than 83 undergoes _____.
Answer:
spontaneous process.

Question 8.
______ radioactive material is present in the ore of pitchblende.
Answer:
Uranium.

Question 9.
_____ are the example of artificial (or) man-made radioactive elements.
Answer:
Boron, Aluminium.

Question 10.
The element whose atomic number is less than 83 undergoes _____.
Answer:
induced radioactivity.

Question 11.
______ is an controlled manner.
Answer:
Artificial radioactivity.

Question 12.
Spontaneous radioactivity is also known as _____.
Answer:
Natural radioactivity.

Question 13.
One Curie is equal to _____ disintegrations per second.
Answer:
3.7 × 1010

Question 14.
One Rutherford (Rd) is equal to ______ disintegrations per second.
Answer:
106

Question 15.
The radioactive displacement law is framed by _____.
Answer:
Soddy and Fajan.

Question 16.
During the α decay process, the atomic number is ______ by 2 and the mass number is decreases by _____.
Answer:
decreases, 4.

Question 17.
In β-decay the atomic number increases by ____ unit and mass number _____.
Answer:
One, remains the same.

Question 18.
In α radiation, the charge of each alpha particle is _____.
Answer:
+2e.

Question 19.
In γ radiation, the charge of each gamma particle is _____.
Answer:
Zero.

Question 20.
In radioactive radiation, which one is travel with the speed of light _____.
Answer:
Gamma radiation.

Question 21.
zYA→z−2YA−4+X; Then X is _____.
Answer:
2He4 (α decay).

Question 22.
zYA→zYA+X; Then X is _____.
Answer:
γ decay.

Question 23.
The average energy released in each fission process in about _____.
Answer:
3.2 × 10-11 J.

Question 24.
Fissionable material is a radioactive element, which undergoes fission in a sustained manner when it absorbs a _____.
Answer:
Neutron.

Question 25.
_____ isotope is used to detect the presence of block in blood vessels and also used for the effective functioning of the heart.
Answer:
Na24 – Radio sodium.

Question 26.
_____ is used to cure goitre.
Answer:
Radio Iodine – I131

Question 27.
_____ is used to diagnose anaemia and also to provide treatment for the same.
Answer:
Radio – iron (Fe59).

Question 28.
Radio cobalt (Co60) and radio gold (Au198) are used in the treatment of _____.
Answer:
Skin cancer.

Question 29.
_____ are used to sterilize the surgical devices as they can kill the germs and microbes.
Answer:
Radiations.

Question 30.
The age of the earth, fossils, old paintings and monuments can be determined by _____. technique.
Answer:
Radiocarbon dating.

Question 31.
When the body is exposed to about 600 R, it leads to _____.
Answer:
Death.

Question 32.
Radioactive materials should be kept in a thick – walled container of _____.
Answer:
Lead.

Question 33.
_____ is used to remove the heat produced in the reactor core, to produce steam.
Answer:
Coolant.

Question 34.
The abbreviation of BARC is _____.
Answer:
Bhabha Atomic Research Centre.

Question 35.
India’s 1st nuclear power station is _____.
Answer:
Tarapur Atomic Power Station.

Question 36.
The first nuclear reactor built in India was _____.
Answer:
Apsara.

Question 37.
The total nuclear power operating sites in India is _____.
Answer:
7

Question 38.
The energy released in a nuclear fission process is about ______
Answer:
200 Mev.

Question 39.
The number of 0n1 released on an average per fission is _____.
Answer:
2.5.

Question 40.
A hydrogen bomb is based on the principle of _____.
Answer:
Nuclear fusion.

III. Match the following

Question 1.

1. Natural radioactivity(a) 3.7 × 1010decay/second
2. Artificial radioactivity(b) spontaneous process
3. 1 curie(c) 106decay/second
4. 1 Rd (Rutherford)(d) induced process

Answer:
1. (b) spontaneous process
2. (d) induced process
3. (a) 3.7 × 1010 decay / second
4. (c) 106 decay / second

Question 2.

1. Charge of each α particle(a) γ ray
2. Charge of each β particle(b) +2e
3. Penetration power is maximum(c) α ray
4. Ionisation power is maximum(d) zero

Answer:
1. (b) +2e
2. (d) zero
3. (a) γ ray
4. (e) α ray

Question 3.

1. Deuterium(a) −1e0
2. Protium(b) 1H3
3. Tritium(c) 2H4
4. α – decay(d) 1H1
5. β – decay(e) 1H2

Answer:
1. (e) 1H2
2. (d) 1H1
3. (b) 1H3
4. (c) 2H4
5. (a) −1e0

Question 4.

1. Uranium core bomb(a) fusion bomb
2. Plutonium core bomb(b) fission bomb
3. Hydrogen bomb(c) Nagasaki
4. Atom bomb(d) Hiroshima

Answer:
1. (d) Hiroshima
2. (c) Nagasaki
3. (a) fusion bomb
4. (b) fission bomb

Question 5.

1. Radio iron (Fe59)(a) treatment of skin diseases
2. Radio phosphorous (P32)(b) smoke detector
3. Radio gold (Au198)(c) diagnose anaemia
4. An isotope of Americium (Am241)(d) treatment of skin cancer

Answer:
1. (c) diagnose anaemia
2. (a) treatment of skin diseases
3. (d) treatment of skin cancer
4. (b) smoke detector

IV. Arrange the following in the correct sequence

Question 1.
Arrange α, β, γ rays in ascending order, on the basis of their penetrating power?
Answer:
Ascending order:

  • Alpha (α)
  • Beta (β)
  • Gamma (γ)

Question 2.
Arrange in ascending and descending order, on the basis of their Ionisation power.
Alpha (α), Beta (β), Gamma (γ)
Answer:

  1. Ascending order: Gamma (γ), Beta (β), Alpha (α)
  2. Descending order: Alpha (α), Beta (β), Gamma (γ)

Question 3.
Arrange in ascending and descending order, on the basis of their biological effect.
Alpha (α), Gamma (γ), Beta (β)
Answer:

  1. Ascending order: Alpha (α), Beta (β), Gamma (γ)
  2. Descending order: Gamma (γ), Beta (β), Alpha (α).

V. Numerical Problems

Question 1.
92U238 emits 8α particles and 6β particles. What is the neutron / proton ratio in the product nucleus?
Solution:

Question 2.
The element with atomic number 84 and mass number 218 change to another element with atomic number 84 and mass number 214. The number of α and β particles emitted are respectively?
Solution:
Samacheer Kalvi 10th Science Solutions Chapter 6 Nuclear Physics 8
Number of alpha decay, x = 1
Number of beta decay, y = 2.

Question 3.
The number of α and β particles emitted in the nuclear reaction 90Th228⟶83Bi12are respectively.
Solution:
Samacheer Kalvi 10th Science Solutions Chapter 6 Nuclear Physics 9
Number of α decay, x = 4
Number of β decay, y = 1.

VI. Assertion and Reason Type Questions

(a) If both the assertion and the reason are true and the reason is the correct explanation of the assertion.
(b) If both the assertion and the reason are true, but the reason is not the correct explanation of the assertion.
(c) If Assertion is true, but the reason is false.
(d) If Assertion is false, but the reason is true.
(e) If the Assertion and reason both are false.

Question 1.
Assertion: All the radioactive element are ultimately converted in lead.
Reason: All the elements above lead are unstable.
Answer:
(c) If Assertion is true, but the reason is false.
Explanation: When they are converted into a lead, the emission is stopped because the nucleus of lead is stable (or lead is most stable elements in radioactive series)

Question 2.
Assertion: Among the alpha, beta and gamma-ray a particle has maximum penetrating power.
Reason: The alpha particle is heavier than beta and gamma rays.
Answer:
(e) If the Assertion and reason both are false.
Explanation: The penetrating power is maximum in case of gamma rays because gamma rays are electromagnetic radiation of very small wavelength.

Question 3.
Assertion: The ionising power of β – particle is less compared to α – particles but their penetrating power is more.
Reason: The mass of β-particle is less than the mass of α-particle
Answer:
(b) If both the assertion and the reason are true, but the reason is not the correct explanation of the assertion.
Explanation: β – particle being emitted with very high speed compared to α – particle. Due to this reason, their loss of energy is very slow and they can penetrate the medium through a sufficient depth.

Question 4.
Assertion: Neutrons penetrate matter more readily as compared to protons.
Reason: Neutrons are slightly more massive than protons.
Answer:
(b) If both the assertion and the reason are true, but the reason is not the correct explanation of the assertion.
Explanation: Neutron is about 0.1 % more massive than a proton. But the unique thing about the neutron is that while it is heavy, it has no charge (it is neutral). This lack of charge gives it the ability to penetrate matter without interacting as quickly as the beta particles or alpha particles.

Question 5.
Assertion: zXA undergoes a decays and the daughter product is z−2YA−4
Reason: In α – decay, the mass number decreases by 4 and atomic number decreases by.
Answer:
(a) If both the assertion and the reason are true and the reason is the correct explanation of the assertion.
Explanation: zXA⟶z−2XA−4+2He4(α decay)

Question 6.
Assertion: Moderator is used to slowing down the high energy neutrons to provide slow neutrons.
Reason: Cadmium rods are used as control rods.
Answer:
(b) If both the assertion and the reason are true, but the reason is not the correct explanation of the assertion.
Explanation: Graphites and heavy water are commonly used moderators. This helps in moderator to slow down the fast neutrons.

Question 7.
Assertion: Alpha, beta and gamma radiations are emitted.
Reason: Nuclear fission process can be performed at room temperature.
Answer:
(a) If both the assertion and the reason are true and the reason is the correct explanation of the assertion.
Explanation: At room temperature, the nuclear fission process can perform breaking up of heavier nucleus into two smaller nuclei. In this process to emitted the alpha, beta and gamma radiations.

Question 8.
Assertion: An enormous amount of energy is released which is called stellar energy.
Reason: Fusion reaction that takes place in the cores of the Sun and other stars.
Answer:
(a) If both the assertion and the reason are true and the reason is the correct explanation of the assertion.
Explanation: The stars like our Sun emit a large amount of energy in the form of light and heat. This energy is termed as the stellar energy.

Question 9.
Assertion: Artificial radioactivity is a controlled process.
Reason: It is a spontaneous process – natural radioactivity.
Answer:
(b) If both the assertion and the reason are true, but the reason is not the correct explanation of the assertion.
Explanation: Artificial radioactivity is a controlled process. It is an induced process and man-made radioactivity.

Question 10.
Assertion: Gamma rays, penetrates through materials most effectively.
Reason: Gamma rays, which have the shortest wavelengths of all electromagnetic radiation.
Answer:
(a) If both the assertion and the reason are true and the reason is the correct explanation of the assertion.
Explanation: Gamma rays, which have the shortest wavelengths of all electromagnetic radiation. This is a reason they can penetrate through materials most effectively.

VII. Answer the following questions

Question 1.
Define ‘Radioactivity’.
Answer:
The phenomenon of nuclear decay of certain elements with the emission of radiations like alpha, beta, and gamma rays is called ‘radioactivity’.

Question 2.
By whom radioactivity is detected in pitchblende?
Answer:
Marie curie and Purie curie.

Question 3.
Define ‘Artificial Radioactivity’.
Answer:
The phenomenon by which even light elements are made radioactive, by artificial or induced methods, is called ‘Artificial radioactivity’ or ‘Man – made radioactivity’.

Question 4.
Define ‘One curie’.
Answer:
It is defined as the quantity of a radioactive substance which undergoes 3.7 × 1010 disintegrations in one second. This is actually close to the activity of 1 g of radium 226.
Curie = 3.7 × 1010 disintegrations per second.

Question 5.
In which elements artifical radioactivity is induced?
Answer:
Boron and aluminum

Question 6.
What is alpha decay (α decay)? give an example.
Answer:
A nuclear reaction in which an unstable parent nucleus emits an alpha particle and forms a stable daughter nucleus is called ‘alpha decay’.
E.g. Decay of uranium (U238) to thorium (Th234) with the emission of an alpha particle.
92U238→90Th234+2He4 (α – decay).

Question 7.
What is beta decay (β decay)? Give an example?
Answer:
A nuclear reaction, in which an unstable parent nucleus emits a beta particle and forms a stable daughter nucleus, is called ‘beta decay’.
E.g. Beta decay of phosphorous.
15P32→16S32+−1e0 (β – decay)

Question 8.
What is gamma decay (γ decay)?
Answer:
In a γ – decay, only the energy level of the nucleus changes. The atomic number and mass number of the radioactive nucleus remain the same.

Question 9.
State the value of Roentgen in terms of Coulomb.
Answer:
Roentgen = 2.58 × 10-4 Coulomb in / kg of air.

Question 10.
Define ‘nuclear fission’ Give an example.
Answer:
The process of breaking (splitting) up of a heavier nucleus into two smaller nuclei with the release of a large amount of energy and a few neutrons are called ‘nuclear fission’.
E.g. Nuclear fission of a uranium nucleus (U235)
92U235+0n1→56Ba141+36Kr92+30n1+Q( energy )

Question 11.
Define ‘Nuclear fusion’ Give an example.
Answer:
The process in which two light nuclei combine to form a heavier nucleus is termed as ‘Nuclear fusion’.
E.g. 1H2+1H2→2He4+Q( Energy )

Question 12.
Write down the types of the nuclear reactor.
Answer:
Breeder reactor, fast breeder reactor, pressurized water reactor, pressurized heavy water reactor, boiling water reactor, water – cooled reactor, gas – cooled reactor, fusion reactor and thermal reactor are some types of nuclear reactors, which are used in different places worldwide.

Question 13.
What is the safe limit of receiving radioactive radiations?
Answer:
100 m R per week

VIII. Answer in the details:

Question 1.
Explain the principle and working of an atom bomb?
Answer:
Atom bomb:
(i) The atom bomb is based on the principle of the uncontrolled chain reaction. In an uncontrolled chain reaction, the number of neutrons and the number of fission reactions multiply almost in a geometrical progression.

(ii) This releases a huge amount of energy in a very small time interval and leads to an explosion.

Structure:
(i) An atom bomb consists of a piece of fissile material whose mass is subcritical. This piece has a cylindrical void.

(ii) It has a cylindrical fissile material which can fit into this void and its mass is also subcritical. When the bomb has to be exploded, this cylinder is injected into the void using a conventional explosive.

(iii) The two pieces of fissile material join to form the supercritical mass, which leads to an explosion. During this explosion, a tremendous amount of energy in the form of heat, light and radiation is released.

(iv) A region of very high temperature and pressure is formed in a fraction of a second along with the emission of hazardous radiation like y rays, which adversely affect the living creatures. This type of atom bombs was exploded in 1945 at Hiroshima and Nagasaki in Japan during World War II.

Question 2.
State and define the units of radioactivity.
Answer:
Curie : It is the traditional unit of radioactivity. It is defined as the quantity of a radioactive substance which undergoes 3.7 × 1010 disintegrations in one second. This is actually close to the activity of lg of radium 226. 1 curie = 3.7 × 1010 disintegrations per second.

Rutherford (Rd) : It is another unit of radioactivity. It is defined as the quantity of a radioactive substance, which produces 106 disintegrations in one second.
1 Rd = 106 disintegrations per second.

Becquerel (Bq) : It is the SI unit of radioactivity is becquerel. It is defined as the quantity of one disintegration per second.

Roentgen (R) : It is the radiation exposure of γ and x-rays is measured by another unit called roentgen. One roentgen is defined as the quantity of radioactive substance which produces a charge of 2.58 × 10-4 coulomb in 1 kg of air under standard conditions of pressure, temperature and humidity.

Question 3.
Write down the features of nuclear fission and nuclear fusion.
Answer:

Nuclear FissionNuclear Fusion
1. The process of breaking up (splitting) of a heavy nucleus into two smaller nuclei is called ‘nuclear fission’.1. Nuclear fusion is the combination of two lighter nuclei to form a heavier nucleus.
2. Can be performed at room temperature.2. Extremely high temperature and pressure are needed.
3. Alpha, beta and gamma radiations are emitted.3. Alpha rays, positrons, and neutrinos are emitted.
4. Fission leads to emission of gamma radiation. This triggers the mutation in the human gene and causes genetic transform diseases.4. Only light and heat energy are emitted.

Question 4.
Write down the medical and industrial application of radioisotopes?
Answer:

  1. Radio sodium (Na24) is used for the effective functioning of the heart.
  2. Radio – Iodine (I131) is used to cure goitre.
  3. Radio – Iron is (Fe59) is used to diagnose anaemia and also to provide treatment for the same.
  4. Radio Phosphorous (P32) is used in the treatment of skin diseases.
  5. Radio Cobalt (Co60) and radio – gold (Au198) are used in the treatment of skin cancer.
  6. Radiations are used to sterilize the surgical devices as they can kill the germs and microbes.
  7. Radio cobalt (Co60) and radio – gold (Au198) are used in the treatment of skin cancer.
  8. Radiations are used to sterilize the surgical devices as they can kill the germs and microbes.

Question 5.
Write a note about stellar energy.
Answer:
The stars like our Sun emit a large amount of energy in the form of light and heat. This energy is termed as the stellar energy. Where does this high energy come from? All-stars contain a large amount of hydrogen. The surface temperature of the stars is very high which is sufficient to induce fusion of the hydrogen nuclei.

Fusion reaction that takes place in the cores of the Sun and other stars results in an enormous amount of energy, which is called as ‘stellar energy’. Thus, nuclear fusion or thermonuclear reaction is the source of light and heat energy in the Sun and other stars.

IX. Additional HOT Questions

Question 1.
Why is neutron so effective as bombarding particle?
Answer:
A neutron carries no charge. It easily penetrates even a heavy nucleus without being repelled or attracted by nucleus and electrons. So it serves as an ideal projectile for starting a nuclear reaction.

Question 2.
Is there any difference between electron and a beta particle.
Answer:
Basically, there is no difference between an electron and a beta particle. β particle is the name given to an electron emitted from the nucleus.

Question 3.
Why are the control rods made of cadmium?
Answer:
Cadmium has high cross – section for the absorption of neutrons.

Question 4.
Name two radioactive elements that are not found in observable quantities why is it so?
Answer:
Tritium and Plutonium are two radioactive elements that are not found in observable quantities in the universe.
It is because half-life period of each of two elements is very short compared to the age of the universe.


Samacheer, Kalvi, 10th, sslc, Science, Solutions, Chapter 23, Visual Communication, tamilnadu board, 10th Science, Computer Science,

I. Choose the correct answer:

Question 1.
Which software is used to create animation?
(a) Paint
(b) PDF
(c) MS Word
(d) Scratch.
Answer:
(d) Scratch.

Question 2.
All files are stored in the:
(a) Folder
(b) box
(c) Pai
(d) Scanner
Answer:
(a) Folder

Question 3.
Which is used to build scripts?
(a) Script area
(b) Block palette
(c) Stage
(d) Sprite.
Answer:
(a) Script area

Question 4.
Which is used to edit programs?
(a) Inkscape
(b) Script editor
(c) Stage
(d) Sprite
Answer:
(b) Script editor

Question 5.
Where you will create the category of blocks?
(a) Block palette
(b) Block menu
(c) Script area
(d) Sprite.
Answer:
(b) Block menu

II. Match the following:

Question 1.

1. Script Area(a) Type notes
2. Folder(b) Animation software
3. Scratch(c) Edit programs
4. Costume editor(d) Store files
5. Notepad(e) Build Scripts

Answer:

  1. (e) Build Scripts
  2. (d) Store files
  3. (b) Animation software
  4. (c) Edit programs
  5. (a) Type notes.

III. Answer the following:

Question 1.
What is Scratch?
Answer:
‘Scratch’ is a software used to create animations, cartoons and games easily. Scratch, on the other hand, is a visual programming language. It was developed in the Massachusetts Institute of Technology (MIT) Media Lab to make programming easier and more fun to learn.

Question 2.
Write a short note on editor and its type?
Answer:
There are two types of editors. They are (i) Script editor (ii) Costume editor.
Editors are used to edit your programs or your sprite’s pictures. The script editor has three main parts: Script area, Block menu and Block palette. When costume editor tab is chosen, Click → File / New to create new project.

Question 3.
What is Stage?
Answer:
The stage is the background appearing when we open the scratch window. The background will most often be white. You can change the background colour as you like.

Samacheer Kalvi 10th Science Visual Communication Additional Questions Solved

I. Choose the correct answer.

Question 1.
The characters on the background of a scratch window are known as _______.
(a) stage
(b) screen
(c) sprite
(d) script.
Answer:
(c) sprite

Question 2.
Which button is click, it shows the list of all programs in the computer?
(a) My computer
(b) START
(c) Recycle Bin
(d) Explorer
Answer:
(b) START

Question 3.
Choose the correct pair for the following _______.
(a) Stage – bottom left
(b) Sprite list – top left
(c) Script tab – right
(d) None of these.
Answer:
(c) Script tab – right

Question 4.
The device which helps in explaining the concepts easily through pictures is known as:
(a) Visual communication device
(b) Paint
(c) Notepad
(d) Scratch
Answer:
(a) Visual communication device

Question 5.
Choose the correct statement from the following _______.
(a) The output we get from any application is called folder.
(b) Cinema is a good example of VCD.
(c) The characters on the background of a scratch window are known as a stage.
(d) The scratch editor has four main parts.
Answer:
(b) Cinema is a good example of VCD.

Question 6.
Which company was developed by Scratch software?
(a) Massachusetts Institute of Technology (MIT)
(b) Microsoft corporation
(c) Sun micro system
(d) Oracle corporation
Answer:
(a) Massachusetts Institute of Technology (MIT)

Question 7.
The output we get from any application is commonly referred to as _______.
(a) file
(b) folder
(c) hardware
(d) software.
Answer:
(a) file

Question 8.
Choose the correct pair:
(a) Script – Event
(b) Mouse – Output
(c) Visual – blackboard
(d) NEW – Start
Answer:
(a) Script – Event

Question 9.
When we _____ on the mouse, the popup menu appears.
(a) right – click
(b) left click
(c) click
(d) right.
Answer:
(a) right-click

Question 10.
Choose the correct statement:
(a) The scratch editor has two main parts.
(b) The stage background will most often be black.
(c) Block menu, where you build scripts
(d) The script editor right pane also contains two additional tabs, costumes and sounds.
Answer:
(d) The script editor right pane also contains two additional tabs, costumes and sounds.

Question 11.
The list of all programs loaded in the computer is shown when you click _______ button.
(a) Home
(b) list
(c) All programs
(d) start.
Answer:
(d) start.

Question 12.
Which device helps in explaining the concepts easily through pictures?
(a) Audiometer
(b) Video meter
(c) Visual audio device
(d) Visual communication device.
Answer:
(d) Visual communication device.

Question 13.
Which one of the following is a good example of a visual communication device?
(a) Theatre
(b) Cinema
(c) Exhibitions
(d) poster making.
Answer:
(b) Cinema

Question 14.
VCD means _______.
(a) Virtual compact disk
(b) Video compact disc
(c) Visual contract device
(d) Visual communication device.
Answer:
(d) Visual communication device.

Question 15.
Which one of the following is a visual programming language?
(a) Visual Basic
(b) Scratch
(c) Visual C++
(d) paint.
Answer:
(b) Scratch

Question 16.
Expand MIT _______.
(a) Maritime Institute of Technology
(b) Madras Institute of Technology
(c) Massachusetts Institute of Technology
(d) Maldives Institute of Technology.
Answer:
(c) Massachusetts Institute of Technology

Question 17.
The Scratch editors consists of ______ main parts.
(a) 2
(b) 3
(c) 4
(d) 5.
Answer:
(b) 3

Question 18.
Pick the odd one out _______.
(a) Stage
(b) Screen
(c) Sprite
(d) Script editor.
Answer:
(b) Screen

Question 19.
_______ is the background appearing when we open the scratch Window.
(a) Stage
(b) Screen
(c) Sprite
(d) Script.
Answer:
(a) Stage

Question 20.
What is the default colour of the stage?
(a) red
(b) yellow
(c) white
(d) black.
Answer:
(c) white

Question 21.
Find the correct statement from the following?
(a) The background colour of the stage can be changed.
(b) The background colour of the stage cannot be changed.
Answer:
(a) The background colour of the stage can be changed.

Question 23.
The _____ pane also contains two additional tabs like costumes and sounds.
(a) left
(b) right
(c) centre
(d) bottom.
Answer:
(b) right

Question 24.
Find the false statement from the following.
(a) When the costume tab is chosen, the costume editor appears in red colour.
(b) When the costume tab is chosen, the costume editor appears in blue colour.
Answer:
(b) When the costume tab is chosen, the costume editor appears in blue colour.

Question 25.
What is the command used to create a new project?
(a) File →New
(b) File → project New
(c) File → New project
(d) File → project.
Answer:
(a) File → New

Question 26.
Click the _____ flag at the top right comer of the stage to run your program.
(a) red
(b) blue
(c) green
(d) yellow.
Answer:
(c) green

Question 27.
Which is not a part of script editor?
(a) sprite
(b) script area
(c) Block menu
(d) Block palette.
Answer:
(a) sprite

Question 28.
Click the scripts tab and find the play sound block from the ________ menu.
(a) scripts
(b) events
(c) sound
(d) audio.
Answer:
(c) sound

II. Match the following:

Question 1.

1. VCD(a) Storage space
2. File(b) Cinema
3. Folder(c) Software
4. Scratch(d) Specific purpose

Answer:

  1. (b) Cinema
  2. (d) Specific purpose
  3. (a) Storage space
  4. (c) Software.

Question 2.

1. Script tabs(a) Unknown place
2. Build scripts(b) Blocks tab
3. Right pane(c) Script area
4. Guide board(d) Costumes and sounds

Answer:

  1. (b) Blocks tab
  2. (c) Script area
  3. (d) Costumes and sounds
  4. (a) Unknown place.

III. Fill in the blanks:

Question 1.
______ and ____ plays a vital role in the working of the computer.
Answer:
Software, hardware.

Question 2.
In Windows OS, ______ application is used to draw pictures.
Answer:
paint.

Question 3.
In Windows OS, we can collect our notes in ______ application.
Answer:
Notepad.

Question 4.
The ______ tab on the right contains the blocks tabs and scripts area.
Answer:
Scripts.

Question 5.
Click the menu _____ drag a when green flag clicked the block to the scripts area.
Answer:
Script → Event.

Question 6.
Sound is present in _____ option.
Answer:
Script.

Question 7.
Visual programming was developed in the _______.
Answer:
Massachusetts Institute of Technology (MIT).

IV. Short Answer Questions

Question 1.
Define file.
Answer:
The output we get from any application is commonly referred to as ‘file’. Therefore the application for the specific purposes determines the nature of the file.

Question 2.
How can we save data and information in computer?
Answer:
We can save data and information in folders which accommodate a single file or multiple files. So all files are stored in the folder.

Question 3.
Define VCD. (Visual Communication Device)?
Answer:
The device which helps in explaining the concepts easily through pictures is known as ‘Visual Communication Device’. For example photos, audiovisuals, drawings, animations all these can be created easily with the help of the computer. Cinema is a good example of ‘Visual Communication Device’.

Question 4.
Write any four operating systems?
Answer:

  1. Windows
  2. UNIX
  3. LINUX
  4. iOS.

Question 5.
What are the three main parts of the script editor?
Answer:
The script editor has three main parts:

  • Script area: Where you build scripts.
  • Block menu: Where you choose the category of blocks (programming statements) to use.
  • Block palette: Where you choose the block to use.

Question 6.
How will you add sound using the costume tab?
Answer:
When the Costumes tab is chosen, the costume editor, Click File/New to create a new project and enter a project name.
Click File / New to create a new project and enter a project name.

Adding Sound:

  1. Click Spritel in the sprite list and click the Sounds tab.
  2. Try the meow sound already there. If you don’t like it, click the speaker icon to choose a different sound from the sound library.
  3. Click the Scripts tab and find the play sound block from the Sound menu. Add this block to the when space key pressed script. (Select the sound you want from the drop-down list.)
  4. Run your program.

Question 7.
Explain how will you create a new project?
Answer:
Click File / New to create a new project and enter a project name.

V. Long Answer Questions

Question 1.
Explain adding sound with an example.
Answer:
Adding Sound:

  1. Click Spritel in the sprite list and click the Sounds tab.
  2. Try the meow sound already there. If you don’t like it, click the speaker icon to choose a different sound from the sound library.
  3. Click the Scripts tab and find the play sound block from the Sound menu. Add this block when space key pressed script. (Select the sound you want from the drop-down list.)
  4. Run your program.

Example:
Program for print the word “Hello” with sound:

1. Click events in script option.

2. Drag “When Clicked” tab to script area.

3. Click Looks in script option. Drag “say” to script area.

4. Type “Hello “ word in say tab.

5. Click sounds in script option. Drag play sound to script area. Choose the hello sound from the audio file.

6. From File menu choose the Save option.

7. Click the green flag at the top right comer of the stage window to run the program.


Samacheer Kalvi 10th Science Solutions Chapter 23 Visual Communication 8

Question 2.
Explain how will you give movements and loops. Give an example.
Answer:
Click the menu Script → Event, drag a when green flag clicked a block to the scripts area. Your scripts area should look like this:

Click the menu Script → Motion menu, drag a goto x : 0, y : 0 blocks to the scripts area and snap it to the bottom of the when green flag clicked the block.
Your script should look like this:


Add a move 10 steps block to the bottom of your script and change the 10 into 100.

Click the green flag at the top right comer of the stage to run your program.


Samacheer, Kalvi, 10th, sslc, Science, Solutions, Chapter 22, Environmental Management, tamilnadu board, biology,

I. Fill in the blanks.

Question 1.
Deforestation leads to ______ in rainfall.
Answer:
Reduction

Question 2.
Removal of soil particles from the land is called ______
Answer:
Soil erosion

Question 3.
Chipko movement is initiated against ______
Answer:
the cutting down of trees

Question 4.
______ is a biosphere reserve in Tamilnadu.
Answer:
Nilgiris

Question 5.
Tidal energy is ______ type of energy.
Answer:
Non-conventional or renewable

Question 6.
Coal, petroleum and natural gas are called ______ fuels.
Answer:
Fossil

Question 7.
______ is the most commonly used fuel for the production of electricity.
Answer:
Coal

II. State whether True or False. If false, write the correct statement:

Question 1.
Biogas is a fossil fuel.
Answer:
False
Correct statement: Biogas is the mixture of methane, hydrogen sulphide, carbon-di-oxide and hydrogen.

Question 2.
Planting trees increase the groundwater level.
Answer:
True

Question 3.
Habitat destruction caused loss of wildlife.
Answer:
True

Question 4.
Nuclear energy is renewable energy.
Answer:
False
Correct statement: Nuclear energy is a non-renewable energy source. The material used in nuclear plants is not renewable.

Question 5.
Overgrazing prevents soil erosion.
Answer:
False
Correct statement: During overgrazing, most of the plants are eaten up. If the plants or vegetation is retained, the soil is not exposed. Soil erosion occurs due to overgrazing.

Question 6.
Poaching of wild animals is a legal act.
Answer:
False
Correct statement: Poaching should be prohibited.

Question 7.
The national park is a protected park.
Answer:
True

Question 8.
Wildlife protection act was established in 1972.
Answer:
True

III. Match the following:

Question 1.

Column AColumn B
1. Soil erosion(a) energy saving
2. Bio-gas(b) acid rain
3. Natural gas(c) removal of vegetation
4. Greenhouse gas(d) renewable energy
5. CFL bulbs(e) CO2
6. Wind(f) non-renewable energy
7. Solid waste(g) lead and heavy metals

Answer:

  1. (c) Removal of vegetation
  2. (d) Renewable energy
  3. (f) Non-renewable energy
  4. (e) CO2
  5. (a) energy saving
  6. (b) acid rain
  7. (g) Lead and heavy metals

IV. Choose the correct answer:

Question 1.
Which of the following is/are a fossil fuel?
i. Tar
ii. Coal
iii. Petroleum
(a) i only
(b) i and ii
(c) ii and iii
(d) i, ii and iii
Answer:
(c) ii and iii

Question 2.
What are the steps will you adopt for better waste management?
(a) reduce the amount of waste formed
(b) reuse the waste
(c) recycle the waste
(d) all of the above
Answer:
(d) all of the above

Question 3.
The gas released from vehicles exhaust is _________
i. Carbon monoxide
ii. Sulphur dioxide
iii. Oxides of nitrogen
(a) i and ii
(b) i and iii
(c) ii and iii
(d) i, ii and iii
Answer:
(d) i, ii and iii

Question 4.
Soil erosion can be prevented by:
(a) deforestation
(b) afforestation
(c) over growing
(d) removal of vegetation
Answer:
(b) afforestation

Question 5.
A renewable source of energy is ______
(a) petroleum
(b) coal
(c) nuclear fuel
(d) trees
Answer:
(d) trees

Question 6.
Soil erosion is more where there is:
(a) no rain fall
(b) low rainfall
(c) rain fall is high
(d) none of these
Answer:
(c) rain fall is high

Question 7.
An inexhaustible resources is _______
(a) wind power
(b) soil fertility
(c) wildlife
(d) all of the above
Answer:
(d) all of the above

Question 8.
Common energy source in village is:
(a) electricity
(b) coal
(c) biogas
(d) wood and animal dung
Answer:
(d) wood and animal dung

Question 9.
The greenhouse effect refers to _____
(a) cooling of Earth
(b) trapping of UV rays
(c) cultivation of plants
(d) warming of Earth
Answer:
(d) warming of Earth

Question 10.
A cheap, conventional, commercial and inexhaustible source of energy is:
(a) hydropower
(b) solar energy
(c) wind energy
(d) thermal energy
Answer:
(c) wind energy

Question 11.
Global warming will cause _______
(a) raise in the level of oceans
(b) melting of glaciers
(c) sinking of islands
(d) all of these
Answer:
(d) all of these

Question 12.
Which of the following statement is wrong with respect to wind energy?
(a) wind energy is a renewable energy
(b) the blades of wind mill are operated with the help of electric motor
(c) production of wind energy is pollution free
(d) usage of wind energy can reduce the consumption of fossil fuels
Answer:
(b) the blades of wind mill are operated with the help of electric motor

V. Answer in a Sentence.

Question 1.
What will happen if trees are cut down?
Answer:
Soil erosion occurs and ecological imbalance takes place if trees are cut down.

Question 2.
What would happen if the habitat of wild animals is disturbed?
Answer:
If the habitat of wild animal is disturbed it leads to extinction of animals or on the verge of extinction.

Question 3.
What are the agents of soil erosion?
Answer:
The high velocity of wind, air currents, flowing water, landslide, human activities such as deforestation, farming and mining, and overgrazing by cattle are the agents of soil erosion.

Question 4.
Why fossil fuels are to be conserved?
Answer:
The formation of fossil fuels is a very slow process and takes very long period of time for renewals so fossil fuels are to conserved.

Question 5.
Solar energy is renewable energy. How?
Answer:
Solar energy is renewable, free source of energy, that is sustainable and totally inexhaustible.

Question 6.
How are e- wastes generated?
Answer:
e-wastes are spoiled, out dated, non-repairable, electrical and electronic devices like computer components electronic and electrical appliances.

VI. Short Answer Questions

Question 1.
What is the importance of rainwater harvesting?
Answer:
The importance of rainwater harvesting is as follows:

  • overcome the rapid depletion of groundwater levels.
  • To meet the increased demand for water.
  • Reduces flood and soil erosion.
  • Water stored in-ground is not contaminated by human and animal wastes and hence can be used for drinking purpose.

Question 2.
What are the advantages of using biogas?
Answer:

  1. It bums without smoke and therefore causes less pollution.
  2. An excellent way to get rid of organic wastes like bio-waste and sewage material.
  3. Left over slurry is a good manure rich in nitrogen and phosphorus.
  4. It is safe and convenient to use.
  5. It can reduce the amount of greenhouse gases emitted.

Question 3.
What is the environmental effect caused by sewage?
Answer:

  • Sewage is the leading polluter of water resources in India.
  • Different species of fishes are killed.
  • Contaminated water can cause diseases such as e-coli, diarrhoea and hepatitis A.

Question 4.
What are the consequences of deforestation?
Answer:
Deforestation gives rise to ecological problems like floods, drought, soil erosion, loss of wild life, extinction of species, imbalance of biogeochemical cycles, alteration of climatic conditions and desertification.

VII. Long Answer Questions

Question 1.
How does rainwater harvesting structures recharge groundwater?
Answer:
Rainwater harvesting is a technique of collecting and storing rainwater for future use. The main purpose of rainwater harvesting is to make the rainwater percolate under the ground, so as to recharge ‘groundwater level’.

Methods of rainwater harvesting
(i) Rooftop rainwater harvesting: The rainwater that falls on the roof of the houses, apartments and commercial buildings, etc, is collected and stored in the surface tank and is used for domestic purpose.

(ii) Recharge pit: The collected rainwater is directed into the percolation pits through pipes for Alteration. After Alteration, the rainwater enters the recharge pits or ground wells.

  • Digging of tanks or lakes (Eris): Eris is constructed in such a way that, if the water in one eri overflows, it automatically gets diverted to the eri of the next village, as these eris are interconnected.
  • Ooranis: These are small ponds to collect rainwater. They are used for various domestic purposes.

Question 2.
How will you prevent soil erosion?
Answer:

  1. Retain vegetation cover, so that soil is not exposed.
  2. Cattle grazing should be controlled.
  3. Crop rotation and soil management improve soil organic matter.
  4. Runoff water should be stored in the catchment.
  5. Reforestation, terracing and contour ploughing.
  6. Wind speed can be controlled by planting trees in form of a shelter belt.

Question 3.
What are the sources of solid wastes? How are solid wastes managed?
Answer:
Solid wastes mainly include municipal wastes, hospital wastes, industrial wastes and e-wastes, etc. The solid wastes are dumped in the soil, which results in landscape pollution. Solid-waste management involves the collection, treatment and proper disposing of solid material that is discarded from the household and industrial activities.

Methods of solid wastes disposal:

  • Segregation: It is the separation of different type of waste materials like biodegradable and non-biodegradable wastes.
  • Sanitary landfill: Solid wastes are dumped into low lying areas. The layers are compacted by trucks to allow settlement. The waste materials get stabilised in about 2-12 months. The organic matter undergoes decomposition.
  • Incineration: It is the burning of non-biodegradable solid wastes (medical wastes) in the properly constructed furnace at high temperature.
  • Composting: Biodegradable matter of solid wastes is digested by microbial action or earthworms and converted into humus.

Question 4.
Enumerate the importance of forest.
Answer:
Forests are an important component of our environment and are dominated by microorganisms, flowering plants, shrubs, climbers, dense trees and provide a vast habitat for wild animals. Forests also contribute to the economic development of our country. Forests are vital for human life, it is a source for a wide range of renewable natural resource. They provide wood, food, fodder, fibre and medicine.

Forests are major factor of environmental concern. They act as a carbon sink, regulate climatic conditions, increase rainfall, reduce global warming, prevent natural hazards like flood and landslides, protect wildlife and also act as catchments for water conservation. They also play a vital role in maintaining ecological balance.

Question 5.
What are the consequences of soil erosion?
Answer:
The consequences of soil erosion are as follows:

  • It has led to increased pollution and sedimentation in streams and rivers.
  • Clogging the waterways and causing a decrease in fish species.
  • Degraded lands often have less ability to hold on to water.
  • Topsoil is removed.
  • Topsoil quality is reduced.
  • No medium crops to grow in soil with poor quality.
  • Use of artificial fertilizers.
  • Disrupts ecosystem.

Question 6.
Why is the management of forest and wildlife resource considered as a challenging task?
Answer:
People would consider forest is a source of raw materials for the factories and industries, and utilise it for development of human without considering about other organism. There are many stake holders of forest. They are those people who are directly or indirectly involved in forest. Management of forest and called life has to take into account the interest of all stake holders which become a challenging task.

VIII. Assertion and Reasoning Questions

In each of the following question, a statement of assertion (A) is given and a corresponding statement of Reason (R). Of the four statements given below mark the correct answer.
(a) Both assertion and reason are true and the reason is the correct explanation of assertion.
(b) Both assertion and reason are true but the reason is not the correct explanation of assertion.
(c) Assertion is true but the reason is false.
(d) Both assertion and reason are false.

Question 1.
Assertion: Rainwater harvesting is to collect and store rainwater.
Reason: Rainwater can be directed to recharge the underground water source.
Answer:
(a) Both assertion and reason are true and the reason is the correct explanation of assertion.

Question 2.
Assertion: Energy-efficient bulbs like CFL must be used to save electric energy.
Reason: CFL bulbs are costlier than ordinary bulbs, hence using ordinary bulbs can save our money.
Answer:
(c) Assertion is true but the reason is false.

IX. Higher Order Thinking Skills (HOTS) Questions

Question 1.
Although coal and petroleum are produced by the degradation of biomass, yet we need to conserve them. Why?
Answer:

  • The coal and petroleum reserves can get exhausted, if we use them at a rapid rate.
  • The formation of fossil fuel is a very slow process and takes a very long time for renewal.
  • It is necessary to conserve the resource, for the future generation, by reducing their consumption.

Question 2.
What are the objectives for replacing non-conventional energy resources from conventional energy resources?
Answer:
Non conventional energy resources are non-polluting renewable sources which are environmentally clean. It is available in unlimited amount in nature and they can be renewed over a short period of time inexpensive and can be harvested continuously.

Question 3.
Why is the Government imposing a ban on the use of polythene bags and plastics? Suggest alternatives. How is this ban likely to improve the environment?
Answer:
Government is imposing a ban on the use of plastic bags and plastics because,

  • Plastics pollute on land, rivers, ponds and all water bodies and soil, etc.
  • Burning of plastic in open air leads to environmental pollution, due to the release of poisonous gas.
  • The accumulation of plastic bags and plastics prevent the seeping of water into the Earth, which brings down the levels of groundwater.
  • Plastic bags can travel long distances by wind and water. They litter our landscapes and water bodies.

Alternatives:

  • Bring your own containers and bags to buy things from the shop.
  • Use paper wraps or compostable bags with cloth or brown paper.

Improvement of the environment on plastic ban:

  • Improve the health of individuals.
  • Driving to innovate alternatives.
  • Plastic pollution reduced.
  • The nation is safe.

X. Value-Based Questions

Question 1.
Why is it not possible to use solar cells to meet our energy needs? State three reason to support to your answer.
Answer:
In solar cells, the solar panel convert solar energy into electricity, which stored in storage battery. The storage battery gives direct current, which is to be converted into alternating current by an suitable appliances before it can be used to run various, devices. So, it increases the cost of using panels as the source of energy.

In the solar cells the energy is obtained only during the day, when the sun shines. So the solar cells is not used to meet our energy needs.

Question 2.
How would you dispose of the following wastes?

  1. Domestic wastes like vegetable peels
  2. Industrial wastes like metallic cans

Can the disposal protect the environment? How?
Answer:

  1. Domestic wastes have to be thrown out with the trash.
  2. Do vermiform composting system for vegetable wastes which can be used as a manure. Industrial wastes like metallic cans can be recycled.

Question 3.
List any three activities based on 3R approach to conserve natural resources.
Answer:
Recycling : Using recycled material of glass plastic, paper, metal etc.
Reuse : Repeating use of items.
Reduce : Avoid the use of materials which increases the solid waste.
Use of public transport instead of personal transport to reduce to consumption of fuel. Use of materials such as paper should be preferred.

Textbook Activities Solved

Question 1.
Collect information regarding the
(i) Tehri Dam project
(ii) Sardar Sarovar Dam project
Answer:
(i) Tehri Dam project:
Tehri Dam is the highest dam in India and one of the highest in the world. It is a multi-purpose rock and earth-filled embankment dam on the Bhagirathi River near Tehri in Uttarakhand, India. It is the primary dam of the THDC India limited and the Tehri hydro-electric complex. The Tehri Dam withholds a reservoir for irrigation, municipal water supply and the generation of 1000 megawatts of hydroelectricity.

(ii) Sardar Sarovar dam project:
Sardar Sarovar Dam is a gravity dam on the Narmadha river near Navagam. It is a part of the Narmada valley project, a large hydraulic engineering project.
Benefits:

  • Provides irrigation facilities.
  • Drinking water supply.
  • There are two powerhouses, red bed powerhouse and canal head powerhouse with a capacity of 1200 MW and 250 MW, respectively.
  • It provides flood protection.
  • Wildlife sanctuaries are maintained.
  • Development of fisheries.
  • Water supply for industries.
  • Protection of conserved forests.

Samacheer Kalvi 10th Science Environmental Management

Additional Questions Solved

I. Fill in the blanks.

Question 1.
______ is used for generation of _____, at thermal power plants.
Answer:
Coal, Electricity

Question 2.
Petroleum is refined to produce _____ and _____, which are used to run automobiles, trucks, trains and ships, etc.
Answer:
Petrol, Diesel

Question 3.
______ and ______ obtained from petroleum are used as domestic fuel.
Answer:
Kerosene, LPG

Question 4.
Solar energy is obtained from ______
Answer:
Sun

Question 5.
Solar cells convert sunlight directly into ______
Answer:
Electricity

Question 6.
_______ plants convert the kinetic energy of flowing water into electricity.
Answer:
Hydropower

Question 7.
The 3R approach such as _____, _____ and ______ may be followed to effective waste management.
Answer:
Reduce, Reuse and Recycle

Question 8.
_______ is a reserved area for the conservation of entire wildlife including plants and animals.
Answer:
National park

Question 9.
______ is a place reserved exclusively for the use of animals.
Answer:
Sanctuary

Question 10.
Unwanted, non-working and out-dated electronic products become ______
Answer:
e-waste

Question 11.
In India, the forests are classified into ______ forests and ______ forests.
Answer:
Reserved, Protected

Question 12.
The small ponds to collect rainwater is called ______
Answer:
Ooranis

II. Write true or false for the following statements. Correct the false statements:

Question 1.
Conservation of natural resources makes an important contribution to the social and economic development of the country.
Answer:
True

Question 2.
Overexploitation and shrinking of forest resulted, the increase of animals and the nourishment of wildlife.
Answer:
False
Correct statement: Overexploitation and shrinking of forest resulted, in animals becoming extinct, some are threatened and some are on the verge of extinction.

Question 3.
The potential energy possessed by the wind, due to lower speed, that can be converted into chemical power by wind turbines.
Answer:
False
Correct statement: The kinetic energy possessed by the wind is due to its high speed, that can be converted into mechanical power by wind turbines.

Question 4.
The main purpose of rainwater harvesting is to make the rainwater, run on its surface of Earth.
Answer:
False
Correct statement: The main purpose of rainwater harvesting is to make the rainwater, to percolate under the ground, so as to recharge the groundwater level.

Question 5.
The burning of non-biodegradable solid wastes (medical wastes) in the properly constructed furnace at high temperature is called electronic wastes.
Answer:
False
Correct statement: The burning of non-biodegradable solid wastes (medical wastes) in the properly constructed furnace at high temperature is called incineration.

III. Match the following:

Question 1.

1. Van Mahotsav(a) Destruction of forests
2. Bombay Natural History Society(b) Crude oil
3. Deforestation(c) Photovoltaic devices
4. Erosion(d) Afforestation programme
5. Solar cells(e) Conservation of wildlife
6. Petroleum(f) Removal of an upper layer of soil

Answer:

  1. (d) Afforestation programme
  2. (e) Conservation of wildlife
  3. (a) Destruction of forests
  4. (f) Removal of an upper layer of soil
  5. (c) Photovoltaic devices
  6. (b) Crude oil

IV. Choose the correct answer:

Question 1.
The new sources of energy are termed as _______
(a) fossil fuel
(b) Conventional energy resources
(c) Non-conventional sources of energy
(d) conservation
Answer:
(c) non-conventional sources of energy

Question 2.
Disposable plastic plates should not be used because:
(a) They are made of materials with light weight
(b) They are made of toxic materials.
(c) They are made of biodegradable materials.
(d) They are made of non-biodegradable materials.
Answer:
(d) They are made of non-biodegradable materials.

Question 3.
The other name for Biogas is ______
(a) Natural gas
(b) Nitrogen gas
(c) Gobar gas
(d) Shale gas
Answer:
(c) Gobar gas

Question 4.
Wildlife includes:
(a) Wild animals only
(b) Wild plants only
(c) Wild plants and animals
(d) All plants and animals
Answer:
(d) All plants and animals

Question 5.
E-wastes are generally called as _______
(a) garbages
(b) electronic waste
(c) decomposition
(d) solid wastes
Answer:
(b) electronic waste

V. Answer the following shortly.

Question 1.
Why should we conserve forests and wild life?
Answer:
We should conserve forest and wild life to preserve the biodiversity, so as to avoid the loss of ecological stability. Without proper management of forest and wild life, the quality of soil, the water sources, and even the amount of rainfall may be affected.

Question 2.
What are the effects of deforestation?
Answer:
Deforestation gives rise to ecological problems like floods, drought, soil erosion, loss of wildlife, extinction of species, imbalance of biogeochemical cycles, alteration of climatic conditions and desertification.

Question 3.
Name the organisation involved in wild life conservation.
Answer:
Organisations Involved in Conservation of Wildlife

  1. Indian Board for WildLife (IBWL)
  2. World Wildlife Fund (WWF) for Nature
  3. World Conservation Union (WCN) ,
  4. International Union for Conservation of Nature and Natural resources (IUCN)
  5. Convention of International Trade in Endangered Species (CITES)
  6. Bombay Natural History Society
  7. Wild life Preservation Society of India, Dehradun

Question 4.
What are fossil fuels? How are they formed?
Answer:
The fossil fuels are petroleum, coal and natural gas. Due to the anaerobic decomposition of buried dead organisms, by a natural process over millions of years, energy-rich substances are formed. As the accumulating sediment layers produce heat and pressure, the remains of the organisms are gradually transformed into hydrocarbons.

Question 5.
Write the uses of solar cells.
Answer:

  1. It can be used for street lighting, traffic signals, water pumping, battery charging system etc.
  2. It is used in artificial satellites and space probes.
  3. It provides radio and TV transmission to remote areas.
  4. It is used in calculators, electronic toys and watches.

Question 6.
Write short notes about shale gas.
Answer:
Due to the compaction of small old rocks, which contain mud and minerals such as quartz and calcite, trapped beneath Earth’s surface and form the soft finely stratified sedimentary rock called shale. These rocks contain fossil fuels like oil and gas in their pores. This fuel is extracted by a technique called hydraulic fracturing.

Shale drilling could affect groundwater reserves, which can contaminate drinking water. It also affects the fertility of the soil. A million gallons of water is needed to break and release the shale gas which in turn can affect the fertility of the soil.
A million gallons of water is needed to break and release the shale gas, which in turn can affect the water table.

Question 7.
What is Tidal energy? What is it’s advantages?
Answer:
The energy obtained from the movement of water, due to ocean tides is called tidal energy. Tides are the rise and fall of sea level, caused by the combined effects of the gravitational force. A tidal stream is a fast-flowing body of water created by tides. Turbines are placed in tidal streams. When the tides hit the turbine, the turbine rotates and converts the tidal energy into electric energy.
Advantages:

  • It does not produce any pollution.
  • It does not use any fuel and does not produce any waste.
  • Tides are predictable, so tidal energy can be produced at any time.
  • Water is denser than air and therefore can generate electricity at lower speeds than wind turbines.

Question 8.
How is electric energy conserved?
Answer:

  • Use energy-efficient appliances to save electricity like compact fluorescent lamps (CFL), Light Emitting Diode [LED] bulbs and other electrical equipment.
  • Switch off the lights and fans, television and other electrical appliances, when not in use.
  • Switch off the mobile phone chargers when not in use.
  • Use more off solar radiation. Solar water heating system can be used instead of electric geysers.
  • Minimise the use of air conditioners.

Question 9.
What are the sources of e-waste? What is the environmental impact of e-waste?
Answer:
E-wastes are called electronic wastes, which includes the spoiled, outdated; non-repairable electrical and electronic devices. These wastes contain toxic metals like lead, cadmium, chromium and mercury, and also contains iron, copper, silicon, aluminium and gold, which can be recovered. The sources of e-wastes are:

  • Electronic device: Computers, laptops, mobile phones, printers, monitors, televisions, DVD players, calculators, toys and sports equipment.
  • Household electrical appliances: Refrigerators, washing machine, microwave oven, mixer, grinder and water heater, etc.
  • Accessories: Printing cartridges, batteries and chargers.

Environmental impact of e-wastes:
Disposal of any kind of electrical and electronic devices without knowledge can become the landfill and water pollutants.
Electronic equipment contains many heavy metals such as lead and cadmium that can cause severe soil and groundwater pollution. E-waste dumping yards and the places, nearby are polluted and cause a severe health hazard.

Question 10.
What is the 3R approach of ineffective waste management?
Answer:
Reduce, Reuse and Recycle are the 3R approach for effective waste management. Reducing the amount of waste, we produce is the best way to help the environment. Buying products with minimum packaging, not borrowing things which we do not use often, starting a compost bin, saving energy and water by turning are ways to reduce. Reuse materials in their original form or pass those materials on to others, who could use them. Paper cardboard, metals, plastics and textiles, etc can be recycled. The compost or reuse of bio-degradable wastes is also a kind of recycling.

Question 11.
What are non-conventional energy resources? What does it include?
Answer:
The energy resources available in an unlimited amount in nature and they can be renewed over a short period of time, inexpensive and can be harvested continuously is called the non-conventional energy resources.

The non-conventional energy resources include biofuel, bio mass-energy, geothermal energy, water energy (hydroelectric energy and tidal energy), solar energy, wave energy and wind energy.

Question 12.
What is the composition of Bio-gas? How is it formed?
Answer:

  • Bio-gas is the mixture of methane (75%), hydrogen sulphide, carbon dioxide and hydrogen.
  • It is produced by the decomposition of animal wastes (cow dung) and plant wastes in the ‘ absence of oxygen.
  • It is also commonly called as “Gobar gas”, as the starting material used is cow dung, which ~ means gobar in Hindi.

Question 13.
What are hydropower and hydropower electricity?
Answer:
Earth is covered with 71% of water. The technique to harness the water energy, from the flowing water is called the hydropower.

The electrical energy is derived from water flow and water falling from a height. In hilly areas, there is a continuous flow of water in large amounts falling from high slopes. The electricity produced by flowing water is called hydropower electricity.

VII. Answer the following in detail.

Question 1.
What are the aims of wildlife management?
Answer:
The main aim of wildlife conservation are:

  1. To control and limit exploitation of species.
  2. To preserve the plants and animals from extinction.
  3. Maintenance of threatened species and protect species which are on the verge of extinction.
  4. Preserve the endangered species.
  5. To study the ecological relationship of the plants and animals in natural habitat.
  6. Hunting and poaching should be prohibited.
  7. Establishment of National parks, Wildlife sanctuaries, protected areas and Biosphere reserves.

Question 2.
Explain in detail the classification of energy resources.
Answer:
Energy resources can be classified as renewable and non-renewable.
(i) Non-renewable (exhaustible) energy resources:
The energy obtained from sources that cannot renew themselves over a short period of time is called non-renewable energy. They include coal, petroleum, natural gas and nuclear power. The conventional energy resources account for 90% of the world’s production of commercial energy and nuclear power account for 10%.

(ii) Renewable (inexhaustible) energy resources:
Renewable (inexhaustible) energy resources are available in the unlimited amount in nature and they can be renewed over a short period of time, inexpensive and can be harnessed continuously. These are called non-conventional energy resources, which include biofuel, biomass energy, geothermal energy, water energy (hydroelectric energy and tidal energy), solar energy, wave energy and wind energy.

Question 3.
Write a note an shale gas. Explain the environment impact of shale gas.
Answer:
Shale refers to the soft finely stratified sedimentary rock that is formed from the compaction of small old rocks containing mud and minerals – such as quartz and calcite, trapped beneath earth’s surface. These rocks contain fossil fuels like oil and gas in their pores.

The fuel is extracted by a technique called hydraulic fracturing (drilling or well boring of sedimentary rocks layers to reach productive reservoir layers).

Environmental concerns of shale gas:

  1. Shale drilling could affect groundwater reserves, which can contaminate the drinking water resources and also affect the fertility of the soil.
  2. Million gallons of water is needed to break and release the shale gas, which intum can affect the water table.

Question 4.
(a) How does windmill work?
(b) List out the uses of wind energy and the advantages of wind energy.
Answer:
(a) A windmill is a machine, that converts the energy of wind, into rotational energy by broad blade attached to the rotating axis. When the blowing air strikes the blades of the windmill, it exerts force and causes the blades to rotate. The rotational movement of the blades operate the generator and the electricity is produced. The energy output from each windmill is coupled together to get electricity on a commercial scale.

(b) The uses of wind energy are as follows:

  • Generating electricity.
  • Run water pumps and flour mills, etc.
  • Rotatory motion of windmill is used to draw water from wells.

Advantages of wind energy:

  • Wind energy is a free, eco-friendly and renewable source of energy.
  • It does not cause pollution.
  • Expenses on periodic maintenance are low when compared to the other power sources.

Question 5.
(a) What are the sources of sewage or wastewater?
(b) Expiate the methods which involve in conventional wastewater treatment.
Answer:
(a) The sources of sewage or wastewater involve:

  • The domestic purpose or household activities
  • Dye and textile industries
  • Leather industries
  • Sugar and breweries industries
  • Paper and pulp industries

(b) The conventional wastewater treatment methods involve the following step:

  • Pre-screening: Wastewater generated from domestic and industrial activities is screened to remove soil and solid particulates.
  • Aeration: Screened wastewater is pumped to an aeration tank. Here the microbial contaminants are removed by the biological degradation, that occurs, in the presence of air.
  • Sedimentation process: In this process, the solid particles in suspension form are allowed to settle. The particles that settle out from the suspension is known as sludge.
  • Sludge removal: The sludge generated by the degradation process is transferred periodically from the tank for safe disposal.
  • Disinfection: Chlorination and ultraviolet (UV) radiation of treated water is required to remove any microorganism contamination.
  • Water recycling: The water will then be supplied for domestic or industrial purposes.

VII. Higher Order Thinking Skills (HOTS) Questions

Question 1.
There are certain NGOs which ask people to donate their used clothes, toys, school books, house hold items. These NGOs segregate the collected items and distribute them to the needy people. What objectives do these NGOs fulfil by this initiatives?
Answer:
The objective behind this is Reuse and Recycle.

Question 2.
Name the national park, which was first established at Uttarakhand.
Answer:
Jim Corbett national park.

Question 3.
An environmentalist on your visit to your school suggested the use of 3R’s to same the environment. Explain the 3R’s.
Answer:
The 3R’s are Reduce, Reuse and Recycle.
Reuse : Instead of throwing thing away, try to find ways to use them again.
Recycle : Creating new product out of the materials from the old.
Reduce : It is the best way to help the environment by reducing the amount of waste you produce.

Question 4.
Where does India stand at the consumer of crude oil?
Answer:
India is the third-largest consumer of crude oil in the world after the United States and China.

Question 5.
Why does the white marble of Tajmahal become yellow?
Answer:
The Mathura oil refinery owned by Indian Oil Corporation presents around this area, which produces sulphur and nitrogen oxides. The white marble became yellow due to air pollution. The Government of India has set up emission standards around the monument to protect it from the damage.

Question 6.
Name the fourth oldest dam in the world? Where is it located?
Answer:
Kallanai Dam, which is also Called Grand Anicut, is the fourth oldest dam in the world. The dam is located on the river Kaveri, 20 km from the city of Tiruchirappalli.

Question 7.
Where is the world’s largest and tallest wind turbine located?
Answer:
The world’s largest and tallest wind turbine is situated in Hawai. One wind turbine can produce electricity for 300 homes.

Question 8.
Name the health effects of the following E-wastes.
Answer:

  • Lead: Damages the central and peripheral nervous system. It also affects brain development in children.
  • Chromium: Asthmatic bronchitis.
  • Cadmium: Accumulates in kidney and liver; Neural damage.
  • Mercury: Chronic damage to the brain and respiratory system.
  • Plastics including polyvinyl chloride [PVC]: Burning produces, dioxin, which can cause developmental and reproductive problems and damage the immune system.

Samacheer, Kalvi, 10th, sslc, Science, Solutions, Chapter 21, Health and Diseases, tamilnadu board, biology,

I. Choose the Correct Answer.

Question 1.
Tobacco consumption is known to stimulate the secretion of adrenaline. The component causing this could be _______.
(a) Nicotine
(b) Tannic acid
(c) Curcumin
(d) Leptin.
Answer:
(a) Nicotine

Question 2.
World ‘No Tobacco Day’ is observed on:
(a) May 31
(b) June 6
(c) April 22
(d) October 2
Answer:
(a) May 31

Question 3.
Cancer cells are more easily damaged by radiations than normal cells because they are _______.
(a) Different in structure
(b) Non-dividing
(c) Mutated Cells
(d) Undergoing rapid division.
Answer:
(d) Undergoing rapid division.

Question 4.
Which type of cancer affects lymph nodes and spleen?
(a) Carcinoma
(b) Sarcoma
(c) Leukemia
(d) Lymphoma
Answer:
(c) Leukemia

Question 5.
Excessive consumption of alcohol leads to _______.
(a) Loss of memory
(b) Cirrhosis of liver
(c) State of hallucination
(d) Suppression of brain function.
Answer:
(b) Cirrhosis of liver

Question 6.
Coronary heart disease is due to:
(a) Streptococci bacteria
(b) Inflammation of pericardium
(c) Weakening of heart valves
(d) Insufficient blood supply to heart muscles
Answer:
(d) Insufficient blood supply to heart muscles

Question 7.
Cancer of the epithelial cells is called _______.
(a) Leukaemia
(b) Sarcoma
(c) Carcinoma
(d) Lipoma.
Answer:
(c) Carcinoma

Question 8.
Metastasis is associated with:
(a) Malignant tumour
(b) Benign tumour
(c) Both (a) and (b)
(d) Crown gall tumour
Answer:
(a) Malignant tumour

Question 9.
Polyphagia is a condition seen in _______.
(a) Obesity
(b) Diabetes mellitus
(c) Diabetes insipidus
(d) AIDS.
Answer:
(b) Diabetes mellitus

Question 10.
Where does alcohol effect immediately after drinking?
(a) Eyes
(b) Auditory region
(c) Liver
(d) Central Nervous System
Answer:
(d) Central Nervous System

II. State whether True or False. If false, write the correct statement:

Question 1.
AIDS is an epidemic disease.
Answer:
False.
Correct Statement: AIDS is a viral disease.

Question 2.
Cancer-causing genes are called Oncogenes.
Answer:
True.

Question 3.
Obesity is characterized by tumour formation.
Answer:
False.
Correct Statement: Obesity is characterized by an accumulation of excess body fat with an abnormal increase in body weight.

Question 4.
In leukaemia, both WBCs and RBCs increase in number.
Answer:
False.
Correct Statement: Leukemia is characterized by an increase in the formation of white blood cells in the bone marrow and lymph nodes.

Question 5.
Study of the cause of the disease is called aetiology.
Answer:
False.
Correct Statement: Study of a cause of the disease is called Pathology.

Question 6.
AIDS is not transmitted by contact with a patient’s clothes.
Answer:
True.

Question 7.
Type 2 diabetes mellitus results due to insulin deficiency.
Answer:
False.
Correct Statement: In type 2 diabetes mellitus, Insulin production by the Pancreas is normal, but the target cells do not respond to insulin.

Question 8.
Carcinogens are cancer-causing agents.
Answer:
True.

Question 9.
Nicotine is a narcotic drug.
Answer:
False.
Correct Statement: Nicotine is a stimulant, highly harmful and poisonous substance, in Tobacco.

Question 10.
Cirrhosis is associated with the brain disorder.
Answer:
False.
Correct Statement: Liver damage resulting in Fatty liver which leads to Cirrhosis and formation of fibrous tissues.

III. Expand the following abbreviations:

Question 1.

  1. IDDM
  2. HIV
  3. BMI
  4. AIDS
  5. CHD
  6. NIDDM.

Answer:

  1. Insulin Dependent Diabetes Mellitus
  2. Human Immunodeficiency Vims
  3. Body Mass Index
  4. Acquired Immuno Deficiency Syndrome
  5. Coronary Heart Disease
  6. Non – Insulin Dependent Diabetes Mellitus.

IV. Match the following:

Question 1.

1. Sarcoma(a) Stomach cancer
2. Carcinoma(b) Excessive thirst
3. Polydipsia(c) Excessive hunger
4. Polyphagia(d) Lack of blood flow to the heart muscle
5. Myocardial Infarction(e) Connective tissue cancer

Answer:

  1. (e) Connective tissue cancer
  2. (a) Stomach cancer
  3. (b) Excessive thirst
  4. (c) Excessive hunger
  5. (d) Lack of blood flow to the heart muscle.

V. Fill in the blanks:

Question 1.
Cirrhosis is caused in the liver due to excessive use of _______.
Answer:
Alcohol.

Question 2.
A highly poisonous chemical derived from tobacco is _______.
Answer:
Nicotine.

Question 3.
Blood cancer is called _______.
Answer:
Leukaemia.

Question 4.
Less response of a drug to a specific dose with repeated use is called _______.
Answer:
Tolerance.

Question 5.
Insulin resistance is a condition in _______ diabetes mellitus.
Answer:
Type – 2.

VI. Analogy Type Questions.

Identify the first words and their relationship and suggest a suitable word for the fourth blank:

Question 1.
Communicable : AIDS :: Non – communicable : _______.
Answer:
Obesity.

Question 2.
Chemotherapy : Chemicals :: Radiation therapy : _______.
Answer:
Radiation.

Question 3.
Hypertension : Hypercholesterolemia :: Glycosuria : _______.
Answer:
Polyphagia.

VII. Answer in a Sentence.

Question 1.
What are psychotropic drugs?
Answer:
The drugs which act on the brain and alter the behaviour, consciousness, power of thinking and perception, are called Psychotropic drags. They are also called Mood altering drugs.

Question 2.
Mention the diseases caused by tobacco smoke.
Answer:
Bronchitis, pulmonary tuberculosis, emphysema hypoxia, lung cancer, hypertension gastric and duodenal ulcer are diseases caused be tobacco smoke.

Question 3.
What are the contributing factors for obesity?
Answer:
Obesity is due to genetic factors, physical inactivity, overeating and endocrine factors.

Question 4.
What is adult onset diabetes?
Answer:
Type-2 Non Insulin Dependent Diabetes Mellitus (NIDDM) is called as adult onset diabetes.

Question 5.
What is metastasis?
Answer:
The Cancerous cells migrate to distant parts of the body and affect new tissues and this process is called Metastasis.

Question 6.
How does insulin deficiency occur?
Answer:
Insulin deficiency occur due to the destruction of B – cells of the pancreas, characterized by abnormally elevated blood glucose level resulting from inadequate insulin secretion.

VIII. Short Answer Questions

Question 1.
What are the various routes by which transmission of human immunodeficiency virus takes place?
Answer:
HIV is transmitted generally by:

  1. Sexual contact with infected person
  2. Use of contaminated needles or syringes especially in case of intravenous drag abusers
  3. By transfusion of contaminated / infected blood or blood products (iv) From infected mother to her child through placenta.

Question 2.
How is a cancer cell different from a normal cell?
Answer:
Cancer is an abnormal and uncontrolled division of cells that invade and destroy the surrounding tissue, forming a tumour or neoplasm. It is a heterogeneous group of cells, that do not respond to the normal cell division. The cancer cells move to distant parts of bodies such as lungs, bones, liver, skin and brain.

Question 3.
Differentiate between Type-1 and Type-2 diabetes mellitus.
Answer:

Type-1 Diabetes mellitusType-2 Diabetes mellitus
1. People with type – 1 diabetes do not produce insulin in the pancreas.1. People with type – 2 diabetes do not respond to insulin.
2. the immune system destroys insulin – producing beta cells in the pancreas.2. People with type – 2 diabetes are Insulin Resistant. The body produces insulin but unable to use effectively.
3. Cannot be controlled without taking insulin.3. Possible to treat initially without medication or treating with tablets.

Question 4.
Why is a dietary restriction recommended for an obese individual?
Answer:
Obesity has a positive risk factor in development of hypertension, diabetes, gall bladder disease, coronary heart disease and arthritis. To avoid the dietary restriction is recommended for an obese individual.

Question 5.
What precautions can be taken for preventing heart diseases?
Answer:
Diet Management: Reduction in the intake of calories, low saturated fat and cholesterol – rich food, low carbohydrates and common salt are some of the Dietary modifications. Diet rich in polyunsaturated fatty acids is essential. Increase in the intake of fibre diet, fruits and vegetables, protein, minerals and vitamins are needed.

  • Physical activity: Regular exercise, walking and yoga are essential for bodyweight maintenance.
  • Avoid Addictive substances: Alcohol consumption, Psychotropic drugs and smoking are to be avoided.

IX. Long Answer Questions

Question 1.
Suggest measures to overcome the problems of an alcoholic.
Answer:
Education and counselling: Education and proper counselling will help the alcoholics to overcome their problems and stress, to accept failures in their life.
Physical activity : Individuals undergoing rehabilitation should be channelized into healthy activities like reading, music, sports, yoga and meditation.

Seeking help from parents and peer groups : When a problematic situation occurs, the affected individuals should seek help and guidance from parents and peers. This would help them to share their feeling of anxiety, wrong dping and get rid of the habit.

Medical assistance : Individual should seek help from psychologists and psychiatrists to get relieved from this condition and to lead a relaxed and peaceful life.

Alcohol de-addiction and rehabilitation programmes are helpful to the individual so that they could get rid of the problem completely and can lead a normal and healthy life.

Question 2.
Changes in lifestyle is a risk factor for the occurrence of cardiovascular diseases. Can it be modified? If yes, suggest measures for prevention.
Answer:
The lifestyle can be modified to prevent cardiovascular diseases. These are the measures for prevention:

  • Do not smoke or use Tobacco.
  • Do Exercise for about 30 minutes.
  • Eat a heart-healthy diet.
  • Reduce the intake of calories, low saturated fat and cholesterol, low carbohydrates and common salt are some of the dietary modifications.
  • Diet rich in polyunsaturated fatty acids (PUFA) is essential.
  • Increase in the intake of fibre diet, fruits and vegetables, protein, minerals and vitamins are essential.
  • Maintain a healthy weight.
  • Get enough quality sleep.
  • Manage stress.
  • Get regular health screens.
  • Control Blood pressure.
  • Keep the cholesterol and triglyceride levels under control.

X. Higher Order Thinking Skills (HOTS) Questions

Question 1.
What is the role of fat in the cause of atherosclerosis?
Answer:
The deposition of cholesterol in the blood vessels gradually develops from which form a fatty streak called plaque. This blocks the pathway of blood flow by narrowing the blood vessels leading to atherosclerosis.

Question 2.
Eating junk food and consuming soft drinks results in health problems like obesity, still, children prefer. What are the suggestions you would give to avoid children eating junk food / consumption of soft drinks?
Answer:
Suggestions, to avoid children, eating Junk food / consumption of soft drinks.

  • Carry a water bottle and drink water.
  • Instead of soft drinks, drink fruit juices, sports drinks or energy drinks.
  • Base meals around protein, legumes, chickpeas, kidney beans and nuts, etc.
  • Avoid getting extremely hungry.
  • Fight stress.
  • Practice mindful eating.
  • Have a piece of fruit, yoghurt, or some crackers.

Question 3.
Regular physical exercise is advisable for normal functioning of the human body. What are the advantages of practising exercise in daily life?
Answer:

  1. Physical exercises help us to live longer and prevent many chronic diseases.
  2. It improves cardiorespiratory and muscular fitness.
  3. It reduces stress, anxiety and depression and improves our mood.
  4. Improves sleep quality and overall quality of life.

Question 4.
A leading weekly magazine has recently published a survey analysis which says that a number of AIDS patient in the country is increasing day by day. The report says that the awareness among the people about AIDS is still very poor. You are discussing the magazine report in your class and a team of your class decides to help people to fight against the dreadful disease.
(a) What problem do you face when trying to educate the people in your village near your school?
(b) How do you overcome the problem?
Answer:
(a) The main problem, we face, is as follows:

  • AIDS patients find it difficult to accept the news.
  • Many people are afraid of telling others because they feel ashamed or they are worried about being rejected.
  • AIDS patients are really discouraged with anxiety about their future.

(b)

  • Confirm the disease by Western Blot Analysis or ELISA.
  • Antiretroviral drugs and immunostimulating therapy can prolong the life of the infected person.
  • Do not tell anyone about our friend’s HIV.
  • Be there to talk to them.
  • Do things together that can reduce stress. Go for a walk. Do something that we enjoy with our AIDS patient friend.
  • Advice the patient friend to avoid activities that have bad health effects like smoking.
  • Patients with HIV / AIDS should not be isolated from the family and society.

XI. Value-Based Questions

Question 1.
Once a person starts taking drugs or alcohol it is difficult to get rid of the habit. Why?
Answer:
The addictive potential of the drugs pulls the individual into a viscous cycle leading to regular abuse and depending. Moreover, some drugs act in the brain and alter the behaviour, consciousness, power of thinking and perception.

Question 2.
Men addicted to tobacco lead to oxygen deficiency in their body. What could be the possible reason?
Answer:
Carbon monoxide of tobacco smoke binds to the haemoglobin of RBC and decreases its oxygen-carrying capacity causing hypoxia in body tissues.

Question 3.
Name any three foods that are to be avoided and included in the diet of a diabetic patient. Why should it be followed?
Answer:
Refined sugar, carbohydrates rich food and high fat content rich foods should be avoided.
Low carbohydrate and fibre rich diet. Diet comprising whole grains, millet, green leafy vegetables should be included in the diet.

Question 4.
How can informational efforts change people’s HIV knowledge and behaviour?
Answer:

  • Find the latest information about viral suppression and Viral Load Monitoring.
  • Find the latest prevention and how to talk with patients with HIV about, what it means for them.
  • Learn how HIV care providers, can identify and address mental health and substance use disorders to help patients, adhere to HIV treatment and remain in care.

XII. Assertion and Reasoning Questions

In each of the following questions, a statement of Assertion is given and a corresponding statement of Reason is given just below it. Of statements given below mark the correct answer as
(a) If both Assertion and Reason are true and Reason is the correct explanation of Assertion.
(b) If both Assertion Mid Reason is true that Reason is not the correct explanation of Assertion.
(c) The assertion is true but Reason is false.
(d) Both Assertion and Reason are false.

Question 1.
Assertion: All drugs act on the brain.
Reason: Drugs disturb the functioning of the body and mind.
Answer:
(a) If both Assertion and Reason are true and Reason is the correct explanation of Assertion.

Question 2.
Assertion: Excretion of excess glucose in the urine is observed in a person with diabetes mellitus.
Reason: Pancreas is unable to produce sufficient quantity of insulin.
Answer:
(b) If both Assertion and Reason are true that Reason is not the correct explanation of Assertion.

Textbook Activities Solved

Question 1.
Collect pictures of people affected by tobacco chewing and tobacco smoking. Identify which part of the body is affected and the health hazards it can lead to?
Answer:
The students should collect pictures of people affected by Tobacco Chewing and Tobacco smoking.
Health Hazards: Affected part is mouth on Tobacco Chewing. Chewing Tobacco causes mouth cancer, throat cancer, soreness, gum diseases, tooth decay, tooth loss, possible links to other cancer and Cardiovascular diseases.

Tobacco smoking causes Lung diseases causing damaging alveoli, emphysema, chronic bronchitis, cough, cold, wheezing, asthma, pneumonia and lung cancer. It also affects the central nervous system, increases blood pressure and heartbeat. It also damages DNA.

Question 2.
Collect pictures of individuals with normal liver and alcoholic liver, compare and indicate the changes you find in them.
Answer:

  • The students should collect pictures of normal liver and alcoholic liver.
  • Normal liver: Under normal circumstances, the normal liver is smooth with no irregularities. The enzymes mostly reside within the cells of the liver.

Fatty liver disease occurs as a result of alcohol drinking, which leads to cirrhosis and formation of fibrous tissues, which replaces the normal liver tissue.

Question 3.
Prepare a chart showing the food items which are preferable and which should be avoided to prevent high blood pressure and heart disease. Apart from diet what are the other lifestyle modifications to be followed to manage this condition?
Answer:

  1. Food items which are preferable: Whole grains, fruits and vegetables, low – fat dairy products, Green tea, Hibiscus tea, Pineapple juice and low carbohydrate food items.
  2. Food items to be avoided: Salt, Meat, Pickles, Canned Soups, Tomato products, sugar, packaged foods, White bread and packaged snacks, etc.

Other Life Style Modification:

  • Exercise for about 30 minutes.
  • Eat a heart-healthy diet.
  • Do not smoke or use tobacco.
  • Get regular health screenings.
  • Get enough quality sleep.

Samacheer Kalvi 10th Science Health and Diseases

Additional Questions Solved

I. Fill in the blanks.

Question 1.
Tobacco is obtained from the Tobacco plant _____ and ______.
Answer:
Nicotiana tobacco and Nicotiana rustica.

Question 2.
The increased urine output, leading to dehydration is termed as ______.
Answer:
Polyuria.

Question 3.
The inflammation of throat and bronchi due to smoke of Tobacco lead to the conditions of _____ and ______.
Answer:
Bronchitis and Pulmonary tuberculosis.

Question 4.
The study of cancer is called ______.
Answer:
Oncology.

Question 5.
The uncontrolled division of cells destroy the surrounding tissue forming a tumour or ______.
Answer:
Neoplasm.

Question 6.
_____ and ______ hydrocarbons present in tobacco smoke is carcinogenic causing Lung cancer.
Answer:
Benzopyrene and Polycyclic.

II. Write ‘True’ or ‘False’ for the following statements. Correct the false statements:

Question 1.
The psychological dependent persons feel that drugs do not help them to reduce stress.
Answer:
False.
Correct Statement: The psychological dependent persons feel that drugs help them to reduce stress.

Question 2.
Individuals should seek help from psychologists and psychiatrists to get relief from alcohol abuse.
Answer:
True.

Question 3.
Tobacco chewing does not cause oral cancer.
Answer:
False.
Correct Statement: Tobacco chewing causes oral cancer.

Question 4.
In Type – 2 Non – Insulin Dependent Diabetes Mellitus, the target cells respond to insulin and allow the movement of glucose into cells.
Answer:
False.
Correct Statement: In Type – 2 Non – Insulin Dependent Diabetes Mellitus, the target cells do not respond to insulin and does not allow the movement of glucose into cells.

Question 5.
Low Carbohydrate food in the form of starch, complex sugars, and fibre-rich diets are more appropriate for the Dietary management pf Diabetes.
Answer:
True.

III. Expand the following abbreviations:

Question 1.

  1. CVD
  2. HDL
  3. PUFA
  4. NACO
  5. NGO
  6. ELISA
  7. WHO
  8. NCPCR
  9. CPCR
  10. LOL
  11. UV rays.

Answer:

  1. Cardio-vascular Disease
  2. High-Density Lipoprotein
  3. Polyunsaturated Fatty Acids
  4. National AIDS Control Organization
  5. Non-Government Organization
  6. Enzyme-Linked ImmunoSorbent Assay
  7. World Health Organization
  8. National Commission for Protection of Child Rights
  9. Commission for Protection of Child Rights
  10. Low-Density Lipoprotein
  11. Ultra Violet rays.

IV. Match the following:

Question 1.

1. Psychotropic drugs(a) Nicotine
2. Chronic metabolic disorder(b) Emphysema
3. Addiction to Tobacco(c) Polyphagia
4. Excess hunger(d) Polydipsia
5. Inflammation of lung alveoli(e) Mood Altering drugs
6. Loss of water leads to thirst(f) Diabetes Mellitus

Answer:

  1. (e) Mood Altering drugs
  2. (f) Diabetes Mellitus
  3. (a) Nicotine
  4. (c) Polyphagia
  5. (b) Emphysema
  6. (d) Polydipsia.

V. Choose the correct answer.

Question 1.
When powdered tobacco is taken through the nose, it is called ______.
(a) smoking
(b) stimulant
(c) snuffing
(d) addiction.
Answer:
(c) snuffing

Question 2.
Causative factor of cancer is called:
(a) Oncogenes
(b) Radiogenes
(c) Oestrogenes
(d) Carcinogens
Answer:
(d) Carcinogens

Question 3.
Insulin deficiency due to the destruction of β – cells occur in ______.
(a) IDDM
(b) BMI
(c) NIDDM
(d) CVD.
Answer:
(a) IDDM

Question 4.
Which is not cancer?
(a) Leukaemia
(b) Glaucoma
(c) Sarcoma
(d) Carcinogen
Answer:
(b) Glaucoma

Question 5.
The HIV Virus attack the body’s disease – fighting mechanism and the individual is prone to infectious diseases.
(a) Erythrocytes
(b) Thrombocytes
(c) Lymphocytes
(d) platelets.
Answer:
(c) Lymphocytes

VI. Write the correct dates for the following:

Question 1.

  1. December 1st
  2. 4th February
  3. 7th November
  4. May 31st
  5. June 26th.

Answer:

  1. World AIDS Day
  2. World Cancer day
  3. National Cancer awareness day
  4. No Tobacco Day or World Anti-Tobacco day
  5. International day against Drug abuse and Illicit Trafficking.

VII. Answer the following briefly:

Question 1.
What are stimulants?
Answer:
Drugs that increase the activities of Central Nervous System.

Question 2.
What is abuse? What does it include?
Answer:
Abuse refers to cruel, violent, harmful or injurious treatment of another human being. It includes physical, emotional or psychological, verbal, child and sexual abuses.

Question 3.
List the instruction to be given to prevent child sexual abuse.
Answer:

  1. Do not talk to any suspected person or strangers and to maintain a distance.
  2. Not to be alone with unknown person.
  3. To be careful while travelling alone in public or private transport:
  4. Not to receive money, toys, gifts or chocolates from known or unknown person to them without the knowledge of their parents.
  5. Not to allow known or unknown person to touch them.

Question 4.
What is an addiction? What is the effect of addiction on individuals?
Answer:
The physical and mental dependency on – alcohol, smoking and drugs are called addiction. The addictive potential of these substances pulls an individual into a vicious cycle leading to regular abuse and dependency.

Question 5.
What are the symptoms of diabetes?
Answer:
Diabetes mellitus is associated with several metabolic alterations. The most important symptoms are

  1. Increased blood glucose level (Hyperglycemia).
  2. Increased urine output (Polyuria) leading to dehydration.
  3. Loss of water leads to thirst (Polydipsia) resulting in increased fluid intake.
  4. Excessive glucose excreted in urine (Glycosuria).
  5. Excess hunger (Polyphagia) due to loss of glucose in urine.
  6. Fatigue and loss of weight.

Question 6.
Explain the types of cancers on the basis of the tissues from which they are formed?
Answer:
Cancers are classified on the basis of the tissues, from which they are formed:

  • Carcinomas arise from epithelial and glandular tissues.
  • Sarcomas occur in connective and muscular tissue. They include the cancer of bones, cartilage, tendons, adipose tissue and muscles.
  • Leukaemia is characterised by an increase in the formation of white blood cells in the bone marrow and lymph nodes Leukaemia is called blood cancers.

Question 7.
Name the test done to diagnosis Aids.
Answer:
The presence of HIV virus can be confirmed by western Blot analysis or Enzyme Linked Immunosorbent Assay (ELISA)

Question 8.
What is the treatment of cancer and the preventive measures for cancer?
Answer:
The treatment of cancer involves the following methods:

  • Surgery: Tumours are removed by surgery to prevent further spread of cancer cells.
  • Radiation therapy: Tumour cells are irradiated by lethal doses of radiation while protecting the surrounding normal cells.
  • Chemotherapy: It involves the administration of anticancerous drugs, which prevent cell division and are used to kill cancer cells.
  • Immunotherapy: Biological response modifiers like interferons are used to activate the immune system and help in destroying the tumours.

Preventive measures for cancer:

  • Cancer control programmes should focus on primary prevention and early detection.
  • To prevent lung cancer, tobacco smoking is to be avoided.
  • Protective measures to be taken against exposure to toxic pollutants of industries.
  • Excessive exposure to radiation is to be avoided to prevent skin cancer.

Question 9.
Explain the symptoms and treatment of AIDS.
Answer:

  • Infected individuals become immunodeficient.
  • The person becomes more susceptible to viral, bacterial, protozoan and fungal diseases.
  • Swelling of lymph nodes, damage to the brain, loss of memory, lack of appetite and weight loss, fever, chronic diarrhoea, cough, lethargy, pharyngitis, nausea and headache.

1. Diagnosis: The presence of the HIV virus can be detected by Western Blot Analysis or Enzyme – Linked ImmunoSorbent Assay (ELISA).
2. Treatment: Anti – retroviral drugs and immunostimulating therapy can prolong the life of the infected person.

Question 10.
Briefly note down the prevention and control of AIDS.
Answer:
The following steps help in controlling and preventing the spreading of HIV:

  • Screening of blood from blood banks for HIV, before transfusion.
  • Ensuring the use of disposable needles and syringes in hospitals and clinics.
  • Advocating safe sex and the advantages of using condoms.
  • Creating an awareness campaign and educating people on the consequences of AIDS.
  • Persons with HIV / AIDS should not be isolated from the family and society.

Question 11.
What is obesity and body mass Index?
Answer:
Obesity is the state in which there is an accumulation of excess body fat with an abnormal increase in body weight.
Body Mass Index (BMI) is an estimate of body fat and health risk.
BMI = Weight (kg) / Height (m)2

Question 12.
What are the major causes and contributing factors for heart disease?
Answer:
Hypercholesterolemia (High blood cholesterol) and high blood pressure (Hypertension) are the major causes and contributing factors for heart disease.

  1. Heredity (family history)
  2. Diet rich in saturated fat and cholesterol
  3. Obesity, increasing age
  4. Cigarette smoking
  5. Emotional stress
  6. Sedentary lifestyle
  7. Excessive alcohol consumption and
  8. Physical inactivity are some of the causes.

VIII. Identify the first words and their relationship and suggest a suitable word for the fourth blank:

Question 1.
Drug abuse : addictive drug :: Tobacco chewing : ______.
Answer:
Oral cancer or mouth cancer.

Question 2.
Insulin : Diabetes :: Benzopyrene : ______.
Answer:
Lung cancer.

Question 3.
Disease of heart and blood vessels : Cardiovascular disease :: Deposition of cholesterol in the blood vessel : ______.
Answer:
Coronary Heart Disease (CHD).

Question 4.
Deficient blood supply to heart muscle : Ischemia :: Death of the heart muscle tissue : ______.
Answer:
Myocardial Infarction.

Question 5.
HIV Virus : ELISA :: Leukaemia : ______.
Answer:
Blood cancer.

X. Explain the following in detail.

Question 1.
Explain the approaches for protection of an abused child and the prevention of child sexual abuse.
Answer:

  • Child helpline: The Child Helpline provides a social worker who can assist the child by providing food, shelter and protection.
  • Counselling the child: Psychologists and social workers should provide guidance, counselling and continous support to a victim child.
  • Family support: The victimized child should be supported by the family members. They should provide proper care and attention to child to overcome his/her sufferings.
  • Medical care: A child victim of sexual offences should receive medical care and treatment from health care professionals to overcome mental stress and depression.
  • Legal Counsel: The family or the guardian of the child victim shall be entitled to free assistance of a legal counsel for such offence.
  • Rehabilitation: Enrolling in schools and resuming their education is an important step towards the rehabilitation of the child.
  • Community – based efforts: Conducting awareness campaign on child abuse and its prevention.

Question 2.
List out the harmful effects of Alcohol to health.
Answer:
Prolonged use of alcohol depresses the nervous system, by acting as a sedative and analgesic substance. Some of the harmful effects are:

  1. Nerve cell damage resulting in various mental and physical disturbances.
  2. Lack of co-ordination of body organs.
  3. Blurred or reduced vision, results in road accidents.
  4. Dilation of blood vessels which may affect functioning of the heart.
  5. Liver damage resulting in fatty liver which leads to cirrhosis and formation of fibrous tissues.
  6. Body loses its control and consciousness eventually leading to health complications and ultimately to death.

Question 3.
Explain in detail the Smoking Hazards and effects of Tobacco. How can it be prevented?
Answer:
When smoke is inhaled, the chemicals get absorbed by the tissues and cause the following harmful effects:

  • Benzopyrene and polycyclic hydrocarbons present in Tobacco smoke are carcinogenic causing lung cancer.
  • Causes inflammation of throat and bronchi leading to conditions like bronchitis and pulmonary tuberculosis.
  • Inflammation of lung alveoli, decrease surface area for gas exchange and cause emphysema.
  • Carbon monoxide of Tobacco smoke binds to the haemoglobin of RBC and decreases its oxygen-carrying capacity causing hypoxia in body tissues.
  • Increased blood pressure caused by smoking leads to increased risk of heart disease.
  • Causes increased gastric secretion which leads to gastric and duodenal ulcers.
  • Tobacco chewing causes oral cancer (mouth cancer).

Prevention: Adolescents and old people need to avoid these habits. Proper counselling and medical assistance can help an addict to give up the habit of smoking.

XI. Higher Order Thinking Skills (HOTS) Questions

Question 1.
What do the following symbols represent?

Answer:
(a) 1. No Smoking
2. No Alcohol
3. No Psychotropic drugs
(b) 4. No – International Tobacco day
5. Inflammation of Lung Alveoli and decreased surface area.

Question 2.
Some human diseases are transmitted only through blood in one of such diseases, there is a progressive decrease in the number of lymphocytes of the patient.
(a) Name the disease and its causative agent.
(b) Write any two symptoms of it.
Answer:
(a) Name the disease is the AIDS caused by Human Immuno Deficiency Virus.
(b) Weight loss and lack of appetite are the symptoms of AIDS.

Question 3.
Which is the desirable blood cholesterol level for Indians?
Answer:
200 mg / dl.

Question 4.
Which cholesterol lowers the risk of heart disease and which cholesterol increases the risk of heart diseases?
Answer:

  • HDL (High – Density Lipoprotein) or good cholesterol lowers the risk of heart disease.
  • LDL (Low – Density Lipoprotein) or bad cholesterol increases the risk of heart diseases.

Question 5.
What are the two types of tumours?
Answer:

  • Benign tumours or Non – malignant tumours: Remain confined in the organ affected and do not spread to other parts of the body.
  • Malignant tumours: Mass of proliferating cells, which grow very rapidly invading and damaging the surrounding normal tissues.

Question 6.
Name some foods which help to reduce blood sugar levels.
Answer:
Flax seeds containing insoluble fibre, Guava, Tomatoes and spinach are the foods, which helps to reduce blood sugar levels.


Samacheer, Kalvi, 10th, sslc, Science, Solutions, Chapter 20, Breeding and Biotechnology, tamilnadu board, biology,

I. Choose the Correct Answer.

Question 1.
Which method of crop improvement can be practised by a farmer if he is inexperienced?
(a) clonal selection
(b) mass selection
(c) pure line selection
(d) hybridisation.
Answer:
(a) clonal selection

Question 2.
Pusa Komai is a disease resistant variety of:
(a) sugarcane
(b) rice
(c) cow pea
(d) maize
Answer:
(c) cow pea

Question 3.
Himgiri developed by hybridisation and selection for disease resistance against rust pathogens is a variety of ______.
(a) chilli
(b) maize
(c) sugarcane
(d) wheat.
Answer:
(d) wheat.

Question 4.
The miracle rice which saved millions of lives and celebrated its 50th birthday is:
(a) IR 8
(b) IR 24
(c) Atomita 2
(d) Ponni
Answer:
(a) IR 8

Question 5.
Which of the following is used to produce products useful to humans by biotechnology techniques?
(a) enzyme from organism
(b) live organism
(c) vitamins
(d) both (a) and (b).
Answer:
(d) both (a) and (b).

Question 6.
We can cut the DNA with the help of:
(a) scissors
(b) restriction endonucleases
(c) knife
(d) RNAase
Answer:
(b) restriction endonucleases

Question 7.
rDNA is a ______.
(a) vector DNA
(b) circular DNA
(c) recombinant of vector DNA and desired DNA
(d) satellite DNA.
Answer:
(c) recombinant of vector DNA and desired DNA

Question 8.
DNA fingerprinting is based on the principle of identifying sequences of DNA:
(a) single-stranded
(b) mutated
(c) polymorphic
(d) repetitive
Answer:
(d) repetitive

Question 9.
Organisms with a modified endogenous gene or a foreign gene are also known as ______.
(a) transgenic organisms
(b) genetically modified
(c) mutated
(d) both (a) and (b).
Answer:
(a) transgenic organisms

Question 10.
In hexaploid wheat (2n = 6x = 42) the haploid (n) and the basic(x) number of chromosomes are:
(a) n = 7 and x = 21
(b) n = 21 and x = 21
(c) n = 1 and x = 1
(d) n = 21 and x = 7
Answer:
(d) n = 21 and x = 7

II Fill in the blanks.

Question 1.
Economically important crop plants with superior quality are raised by ______.
Answer:
Breeding.

Question 2.
A protein rich wheat variety is ______.
Answer:
Atlas 66.

Question 3.
_______ is the chemical used for doubling the chromosomes.
Answer:
Colchicine.

Question 4.
The scientific process which produces crop plants enriched with desirable nutrients is called ______.
Answer:
Biofortification.

Question 5.
Rice normally grows well in alluvial soil, but _____ is a rice variety produced by mutation breeding that grows well in saline soil.
Answer:
Atomita – 2 rice

Question 6.
_____ technique made it possible to genetically engineer living organism.
Answer:
Recombinant DNA.

Question 7.
Restriction endonucleases cut the DNA molecule at specific positions known as ______.
Answer:
Molecular scissors.

Question 8.
Similar DNA fingerprinting is obtained for ______.
Answer:
Identical twins.

Question 9.
______ cells are undifferentiated mass of cells.
Answer:
Pleuripotent.

Question 10.
In gene cloning, the DNA of interest is integrated in a ______.
Answer:
Vector [plasmid].

III. State whether true or false. If false, write the correct statement.

Question 1.
Raphano brassica is a man – made tetraploid produced by colchicine treatment.
Answer:
True.

Question 2.
The process of producing an organism with more than two sets of chromosome is called mutation.
Answer:
False.
Correct statement: The process of producing an organism with more than two sets of chromosome is called polyploidy.

Question 3.
A group of plants produced from a single plant through vegetative or asexual reproduction are called a pureline.
Answer:
False.
Correct statement: A group of plants produced from a single plant through vegetative or asexual reproduction are called clones.

Question 4.
Iron fortified rice variety determines the protein quality of the cultivated plant.
Answer:
False.
Correct statement: Iron fortified rice variety determines the iron quality of the cultivated plant.

Question 5.
Golden rice is a hybrid.
Answer:
False.
Correct statement: Golden rice is a genetically modified plant.

Question 6.
Bt gene from bacteria can kill insects.
Answer:
True.

Question 7.
In vitro fertilisation means the fertilisation done inside the body.
Answer:
False.
Correct statement: In vitro fertilisation means the fertilisation done outside the body.

Question 8.
DNA fingerprinting technique was developed by Alec Jeffrey.
Answer:
True.

Question 9.
Molecular scissors refers to DNA ligases.
Answer:
False.
Correct statement: Molecular scissors refers to Restriction Enzymes.

IV. Match the following:

Question 1.

Column AColumn B
1. Sonalika(a) Phaseolus mungo
2. IR-8(b) Sugarcane
3. Saccharum(c) Semi-dwarf wheat
4. Mung No. 1(d) Groundnut
5. TMV-2(e) Semi-dwarf Rice
6. Insulin(f) Bacillus thuringienesis
7. Bt toxin(g) Beta carotene
8. Golden rice(h) the first hormone produced using rDNA technique

Answer:

  1. (c) Semi – dwarf wheat
  2. (e) Semi – dwarf Rice
  3. (b) Sugarcane
  4. (a) Phaseolus mungo
  5. (d) Groundnut
  6. (h) the first hormone produced using rDNA technique
  7. (f) Bacillus thuringienesis
  8. (g) Beta carotene.

V. Understand the assertion statement, justify the reason given and choose the correct choice:

(a) The assertion is correct and the reason is wrong.
(b) Reason is correct and the assertion is wrong.
(c) Both assertion and reason are correct.
(d) Both assertion and reason are wrong.

Question 1.
Assertion: Hybrid is superior to either of its parents.
Reason: Hybrid vigour is lost upon inbreeding.
Answer:
(a) The assertion is correct and the reason is wrong.

Question 2.
Assertion: Colchicine reduces the chromosome number.
Reason: It promotes the movement of sister chromatids to the opposite poles.
Answer:
(d) Both assertion and reason are wrong.

Question 3.
Assertion: rDNA is superior over hybridisation techniques.
Reason: Desired genes are inserted without introducing the undesirable genes in target organisms.
Answer:
(c) Both assertion and reason are correct.

VI. Answer in a Sentence

Question 1.
Give the name of the wheat variety having higher dietary fibre and protein.
Answer:
Atlas 66, a protein-rich variety, having higher dietary fibre and protein.

Question 2.
Semi-dwarf varieties were introduced in rice. This was made possible by the presence of dwarfing gene in rice. Name this dwarfing gene.
Answer:
Dee-geo-woo-gen a dwarf variety from China.

Question 3.
Define genetic engineering.
Answer:
Genetic engineering is the manipulation and transfer of genes from one organism to another organism to create a new DNA called recombinant DNA (rDNA). Genetic engineering is also called recombinant DNA technology.

Question 4.
Name the types of stem cells.
Answer:
Embryonic stem cells and somatic stem cells are the types of stem cells.

Question 5.
What are transgenic organisms?
Answer:
Plants or animals expressing a modified endogenous gene or a foreign gene are called transgenic organisms.

Question 6.
State the importance of biofertiliser.
Answer:
Biofertilizer adds nutrients through the natural process of nitrogen fixation, stimulate the plant growth through the synthesis of growth-promoting substance.

VII. Short Answer Questions

Question 1.
Discuss the method of breeding for disease resistance.
Answer:
Plant diseases are caused by pathogens like viruses, bacteria and fungi. This affects crop yield. To develop disease-resistant varieties of crops, that would increase the yield and reduce the use of fungicides and bactericides are important. Some disease-resistant varieties are as follows:

CropVarietyResistance to diseases
WheatHimgiriLeaf and stripe rust, hill bunt
CauliflowerPusa Shubhra, Pusa Snowball K-1Black rot
CowpeaPusa KomalBacterial blight

Question 2.
Name three improved characteristics of wheat that helped India to achieve high productivity.
Answer:
Sonalika, kalyan and sona are the three improved characteristic of wheat that helped India to achieve high productivity.

Question 3.
Name two maize hybrids rich in amino acid lysine.
Answer:
Protina, Shakti and Rathna are lysine – rich maize hybrids, which are developed in India.

Question 4.
Distinguish between
(a) Somatic gene therapy and germline gene therapy.
(b) Undifferentiated cells and differentiated cells.
Answer:
(a) Somatic gene therapy and germline gene therapy.

Somatic gene therapyGermline gene therapy
Somatic gene therapy is the replacement of the defective gene in somatic cells.Germline gene therapy is the replacement of the defective gene in the germ cell (egg and sperm).

(b) Undifferentiated cells and differentiated cells.

Undifferentiated cellsDifferentiated cells
Our body is composed of over 200 specialised cell types, that can carry out specific functions, eg. Neurons or nerve cells that can transmit signals. Pancreatic cells to secrete insulin. These specialised cells are called as differentiated cells.The cells which are variable potency, undifferentiated or unspecialised mass of cells are called stem cells. The stem cells are undifferentiated or unspecialised mass of cells.

Question 5.
State the applications of DNA fingerprinting technique.
Answer:
Applications of DNA Fingerprinting:
(i) DNA fingerprinting technique is widely used in forensic applications like crime investigation such as identifying the culprit. It is also used for paternity testing in case of disputes.
(ii) It also helps in the study of genetic diversity of population, evolution and speciation.

Question 6.
How are stem cells useful in the regenerative process?
Answer:
Sometimes cells, tissues and organs in the body may be permanently damaged or lost due to genetic condition or disease or injury. In such situations, stem cells are used for the treatment of diseases, which is called stem – cell therapy. In treating neurodegenerative disorders like Parkinson’s disease and Alzheimer’s disease neuronal stem cells can be used to replace the damaged or lost neurons.

Question 7.
Differentiate between outbreeding and inbreeding.
Answer:
Inbreeding:
When breeding or mating takes place between animals of the same breed, for about 4 – 6 generations, then it is called inbreeding. Superior males and superior females of the same breed are identified and mated in pairs. It helps in the accumulation of superior genes and the elimination of undesirable genes. Inbreeding depression is the continued inbreeding, which reduces fertility and productivity. Inbreeding exposes harmful recessive genes that are eliminated by selection.

Outbreeding:
The breeding of unrelated animals is outbreeding. The offsprings formed are called hybrids. The hybrids are stronger and vigorous than their parents. Cross between two different species with desirable features of economic value is mated. Mule is superior to the horse in strength, intelligence, ability to work and resistance to diseases, but they are sterile.

VIII. Long Answer Questions

Question 1.
What are the effects of hybrid vigour in animals.
Answer:

  1. Increased production of milk by cattle.
  2. Increased production of egg by poultry.
  3. High quality of meat is produced.
  4. Increased growth rate in domesticated animals.

Question 2.
Describe mutation breeding with an example.
Answer:
The mutation is defined as the sudden heritable change in the nucleotide sequence of DNA in an organism. The genetic variations brings out changes in an organism. The organism which undergoes mutation is called a mutant.
The factors which induce mutations are known as mutagens or mutagenic agents. The mutagens are of two types:
(a) Physical mutagens: Radiations like X – rays, a, P and Y – rays, UV rays and temperature, etc, which induce, maturations are called physical mutagens.

(b) Chemical mutagens: Chemical substances that induce mutations are called chemical mutagens, eg. Mustard gas and nitrous acid. The utilization of induced mutation in crop improvement is called mutation inbreeding.
Achievements of mutation breeding:

  • Sharbati Sonora wheat produced from Sonora – 64 by using gamma rays.
  • Atomica – 2 rice with saline tolerance and pest resistance.
  • Groundnuts with thick shells.

Question 3.
Biofortification may help in removing hidden hunger. How?
Answer:
Biofortification: Biofortification is the scientific process of developing crop plants enriched with high levels of desirable nutrients like vitamins, proteins and minerals. Some examples of crop varieties developed as a result of biofortification are given below:

  1. Protina, Shakti and Rathna are lysine rich maize hybrids (developed in India).
  2. Atlas 66, a protein rich wheat variety.
  3. Iron rich fortified rice variety’.
  4. Vitamin A enriched carrots, pumpkin and spinach.

Question 4.
With a neat labelled diagram explain the techniques involved in gene cloning.
Answer:
The carbon copy or more appropriately, a clone means to make a genetically exact copy of an organism. ‘Dolly’ is the cloned sheep.

In gene cloning, a gene or a piece of DNA fragment is inserted into a bacterial cell, where DNA will be multiplied (copied) as the cell divides.
The basic steps involved in gene cloning are:

  • Isolation of desired DNA fragment by using restriction enzymes.
  • Insertion of the DNA fragment into a suitable vector (plasmid) to make rDNA.
  • Transfer of rDNA into the bacterial host cell (Transformation).
  • Selection and multiplication of the recombinant host cell to get a clone.
  • Expression of the cloned gene in the host cell.

Using this strategy several enzymes, hormones and vaccines can be produced.

Question 5.
Discuss the importance of biotechnology in the field of medicine.
Answer:
Using genetic engineering techniques medicinally important valuable proteins or polypeptides that form the potential pharmaceutical products for the treatment of various diseases have been developed on a commercial scale.
Pharmaceutical products developed by rDNA technique:

  1. Insulin used in the treatment of diabetes.
  2. Human growth hormone used for treating children with growth deficiencies.
  3. Blood clotting factors are developed to treat haemophilia.
  4. Tissue plasminogen activator is used to dissolve blood clots and prevent heart attack.
  5. Development of vaccines against various diseases like Hepatitis B and rabies.

IX. Higher Order Thinking Skills (HOTS) Questions

Question 1.
A breeder wishes to incorporate desirable characters into the crop plants. Prepare a list of characters he will incorporate.
Answer:
The list of character he will incorporate are:

  1. High yielding and better quantity
  2. Disease resistance
  3. Insects pest resistance
  4. Improved nutritional quality
  5. Short duration

Question 2.
Organic farming is better than Green Revolution. Give reasons.
Answer:

  • Dwarfness is desired in cereals, so fewer nutrients are consumed by the crops.
  • Fertilizer is responsive.
  • Disease resistant varieties.
  • Insect and pest resistant crop varieties.
  • High levels of desirable nutrients like vitamins, proteins and minerals.

Question 3.
Polyploids are characterised by gigantism. Justify your answer.
Answer:
An organism having more than two set of chromosome is called polyploidy. It can be induced by physical agents such as heat or cold treatment, X-rays and chemical agents like colchicine. As organisms produced by polyploidy have more than two set of chromosomes they are gigantic.

Question 4.
‘P’ is a gene required for the synthesis of vitamin A. It is integrated with the genome of ‘Q’ to produce genetically modified plant ‘R’.
(i) What is P, Q and R?
(ii) State the importance of ‘R’ in India.
Answer:
(i)  The P, Q and R:

  • P – Beta – carotene gene.
  • Q – Prevent vitamin A deficiency.
  • R – Golden rice.

(ii) Importance of rice in India:

  • Rice is the most important staple food for millions of people in developing countries like India.
  • Beta – carotene is produced in the endosperm of the grain. It could control the chronic health problems caused by vitamin A deficiency, especially among the poor in developing countries like India.

Samacheer Kalvi 10th Science Breeding and Biotechnology

Additional Questions Solved

I. Fill in the blanks.

Question 1.
Plant ______ is the art of developing economically important plants.
Answer:
Breeding.

Question 2.
Plant diseases are caused by ______ like viruses, bacteria and fungi.
Answer:
Pathogen.

Question 3.
______ is the first man – made cereal hybrid.
Answer:
Triticale.

Question 4.
The superiority of the hybrid obtained by cross-breeding is called _____ or ______.
Answer:
Heterosis
or
Hybrid vigour.

Question 5.
The other name for genetic engineering is ______.
Answer:
Recombinant DNA technology.

Question 6.
The organism which undergoes mutation is called a ______ and the factors which induce mutations are ______.
Answer:
Mutant; mutagenic agents.

Question 7.
The replacement of the defective gene in a germ cell (egg or sperm) is called ______.
Answer:
Germline gene therapy.

Question 8.
Blood clotting factors are developed to treat ______.
Answer:
Haemophilia.

Question 9.
Stem cells, which are undifferentiated or unspecialised mass of cells can be used for the treatment is called ______.
Answer:
Stem cell therapy.

Question 10.
_______ is used in the treatment of diabetes.
Answer:
Insulin.

II. Match the following:

Question 1.

1. Cowpea(a) Joining the DNA fragments
2. UV rays(b) New breed of sheep
3. Lady’s finger(c) Bacterial blight
4. DNA ligase(d) Flat bean
5. Pusasem 3(e) Pusa Sawani
6. Hissardale(f) Induce mutation

Answer:
1. (c) Bacterial blight
2. (f) Induce mutation
3. (e) Pusa Sawani
4. (a) Joining the DNA fragments
5. (d) Flat bean
6. (b) New breed of sheep.

III. Write “True or False” statements. Correct the false statements:

Question 1.
Modem Agricultural practices are activities carried out to improve the plants.
Answer:
True.

Question 2.
When breeding takes place between animals of the same breed, it is called outbreeding.
Answer:
False.
Correct statement: When breeding takes place between animals of the same breed, it is called inbreeding.

Question 3.
The process of introducing high yielding varieties of plants from one place to another is called a selection.
Answer:
False.
Correct statement: The process of introducing high yielding varieties of plants from one place to another is called Exotic species.

Question 4.
The mutation is a sudden inheritable change in the nucleus sequence of DNA in an organism.
Answer:
False.
Correct statement: Mutation is a sudden heritable change in the nucleotide sequence of DNA in an organism.

Question 5.
A breed is a group of animals of common origin within a species, which has certain characters, that are not found in other members of the same species.
Answer:
True.

IV. Choose the correct answer.

Question 1.
The high yielding rice variety from Indonesia and China are ______.
(a) Peta and DGWG
(b) IR-8 and Gold rice
(c) Hexaploid Triticale and Triticum durum
(d) Sonalika and Kalyan Sona.
Answer:
(a) Peta and DGWG

Question 2.
First artificially synthesized hormone is:
(a) Secretin
(b) Insulin
(c) Glucagon
(d) Renin
Answer:
(b) Insulin

Question 3.
The presence of this substance in bacteria can undergo replication independently along with chromosomal DNA ______.
(a) heritable
(b) colchicine
(c) mutation
(d) plasmid.
Answer:
(d) plasmid.

Question 4.
Bacillus thuringiensis (Bt) stains have been used for designing novel.
(a) Bio-metallogical techniques
(b) Bio-insecticidal plants
(c) Bio-mineralization
(d) Bio-fertilizer
Answer:
(b) Bio-insecticidal plants

Question 5.
A group of plants produced from a single plant through vegetative or asexual reproduction is called ______.
(a) Transgenic
(b) Hexaploid
(c) clones
(d) mutation.
Answer:
(b) Hexaploid

V. Answer the following briefly:

Question 1.
What is the green revolution? Who is the “Father of Green Revolution”?
Answer:
Green Revolution is the process of increasing food production through high yielding crop varieties and modem agricultural techniques in underdeveloped and developing nations. Dr Norman. E. Borlaug, an American agronomist is the “Father of Green Revolution”.

Question 2.
Write the role of polyploidy in crop improvement.
Answer:
The role of polyploidy in crop improvement are production of:

  1. Seedless watermelons (3n) and bananas (3n).
  2. TV-29 (triploid variety of tea) with larger shoots and drought tolerance.
  3. Triticale (6n) is a hybrid of wheat and rye. To make this plant fertile polyploidy is induced. It has higher dietary fibre and protein.
  4. Raphanobrassica is an allotetraploid by colchicine treatment.

Question 3.
What is Bio – fortification? Give any two examples.
Answer:
Bio – fortification is the scientific process of developing crop plants enriched with high levels of desirable nutrients like vitamins, proteins and minerals.
Examples of crop varieties developed as a result of bio – fortification are:

  • Protina, Shakti and Rathna are lysine – rich maize hybrids.
  • Atlas 66, A protein – rich wheat variety.

Question 4.
Give two examples of cross-breeding in animals.
Answer:
Cross breed of fowls: White Leghorn X Plymouth Rock

Hybrid fowl – yield more eggs

Cross breed of cows : Developed by mating the bulls of exotic breeds and cows of indigenous breeds.
Brown Swiss X Sahiwal

Karan Swiss – yield 2-3 times more milk than indigenous cows.

Question 5.
What is hybridization? Explain the hybridization experiment.
Answer:
The process of crossing two or more types of plants for bringing their desired characters together into one progeny hybrid is called hybridization. Hybridization is creating a genetic variation to get improved varieties.

Hybridization Experiment:
Triticale is the first man-made cereal hybrid. It is obtained by crossing wheat (Triticum durum, 2n = 28) and rye (Secale cereal, 2n = 14). The F, a hybrid is sterile (2n = 21). Then the chromosome number is doubled using colchicine and it becomes hexaploid triticale (2n = 42). The cycle of crop raising and selection continues until the plants with the desired characters are finally obtained.

Question 6.
Name the methods of plant breeding for crop improvement.
Answer:
The methods of plant breeding to develop high yielding varieties, for crop improvement, are as follows:

  • Introduction of new varieties of plants
  • Selection
  • Polyploid breeding
  • Mutation breeding
  • Hybridization.

Question 7.
Explain briefly about gene therapy.
Answer:
The replacement of a defective gene by the direct transfer of functional genes into humans to treat genetic disease or disorder is referred to as gene therapy.
The recombinant DNA technology is used for gene therapy:

  • Somatic gene therapy is the replacement of the defective gene in somatic cells.
  • Gene line gene therapy is the replacement of the defective gene in the germ cell (egg or sperm).

Question 8.
What were the important discoveries that led to the stepping stones of recombinant DNA technology?
Answer:

  1. Presence of plasmid in bacteria that can undergo replication independently along with chromosomal DNA.
  2. Restriction enzymes cuts or break DNA at specific sites and are also called as molecular scissors.
  3. DNA ligases are the enzymes which help in ligating (joining) the broken DNA fragments.

Question 9.
What does modern agriculture include?
Answer:
Modem agricultural practices are activities carried out to improve the cultivation of plants. It includes:

  1. Preparation of soil
  2. Sowing
  3. Application of manures and fertilizers
  4. Proper irrigation
  5. Protection from weeds and pests
  6. Harvesting and threshing
  7. Storage

Question 10.
What is the aim of crop improvement?
Answer:
The aim of crop improvement is to develop improved crop varieties possessing higher yield, better quality, resistance to diseases and shorter duration.

Question 11.
(a) What are the two important properties of stem cells?
(b) Write a short note on two types of stem cells.
Answer:
(a) Properties of stem cells:
It’s the ability to divide and give rise to more stem cells by self-renewal.
It’s the ability to give rise to specialised cells with specific functions by the process of differentiation.

(b) Types of cells:

  • Embryonic stem cells: Embryonic stem cells are derived from the inner cell mass of the blastocyst, which can be extracted from the early embryos. These cells can be developed into any cell in the body.
  • Adult stem cell or somatic stem cell: These cells are found in the newborn and adults. They have the ability to divide and give rise to specific cell types. Sources of adult stem cells are amniotic fluid, umbilical cord and bone marrow.

Question 12.
What are bulk genomic DNA and satellite DNA?
Answer:
In human beings, 99 % of the DNA base sequences are the same and this is called a bulk genomic DNA. The remaining 1 % of the DNA sequence differs from one individual to another. This 1 % DNA sequence is present as a small stretch of repeated sequences, which is called satellite DNA.

VI. Answer the following in detail.

Question 1.
What are stem cells? Explain its types.
Answer:
Stem cells are undifferentiated or unspecialised mass of cells. The stem cells are the cells of variable potency. The two important properties of stem cells that differentiate them from other cells are:

  1. Its ability to divide and give rise to more stem cells by self-renewal.
  2. Its ability to give rise to specialised cells with specific functions by the process of differentiation.

Types of stem cells Embryonic stem cells can be extracted and cultured from the early embryos. These cells are derived from the inner cell mass of the blastocyst. These cells can be developed into air, cell in the body.

Adult stem cell or somatic stem cell are found in the neonatal (new bom) and adults. They have tne ability to divide and give rise to specific cell types. Sources of adult stem cells are amniotic fluid, umbilical cord and bone marrow.

Question 2.
Explain with examples the inbreeding and outbreeding of animal breeding.
Answer:
Animal breeding aims at the genotypes of domesticated animals to increase their yield and improve the desirable qualities to produce milk, egg and meat. When breeding takes place between animals of the same breed, it is called inbreeding.
The cross between different – breeds is called outbreeding.

1. Inbreeding:
Inbreeding refers to the mating of closely related animals within the same breed for about 4 – 6 generations. Superior males and superior females of the same breed are identified and mated in pairs. It helps in the accumulation of superior genes and elimination of genes, which are undesirable. Hissardale is a new breed of sheep developed in Punjab by crossing Bikaneri (Magra) ewes and Australian Marino rams.

2. Inbreeding depression:
Continued inbreeding reduces fertility and productivity. Inbreeding exposes harmful recessive genes that are eliminated by selection.

3. Outbreeding:
It is the breeding of unrelated animals. The offsprings formed are called hybrids. The hybrids are stronger and vigorous than their parents. Cross between two different species with desirable features of economic value are mated. Let’s see what cross produce a mule. Mule is superior to a horse in strength, intelligence, ability to work and resistance to diseases but they are sterile

Question 3.
Explain the DNA fingerprinting technology with an illustration.
Answer:
The DNA pattern of two individuals cannot be the same except for identical twins. Each persons DNA sequence is unique, due to the small difference in the base pairs. DNA fingerprinting is the easier and quicker method, to compare the genetic difference among the two individuals. This technique was developed by Alec Jeffrey.

Each individual’s unique DNA sequences provides distinct characteristics of an individual, which helps in identification. A variable number of tandem repeat sequences [VNTRs] serve as molecular markers for identification.

In human beings, 99 % of DNA base sequences are the same and this is called as bulk genomic DNA. The remaining 1 % DNA sequence differs from one individual to another. This 1 % DNA sequence is present as a small stretch of repeated sequences which is called as satellite DNA. The number of copies of the repeat sequence also called VNTRs differs from one individual to another and results in variation in the size of the DNA segment.

As shown in the illustration, the sequence AGCT is repeated six times in the first person, five times in the second person and seven times in the third person. Because of this, the DNA segment of the third person will be larger in size followed by a DNA segment of first – person and then the second person. Thus it is clear that satellite DNA brings about variation within the population. Variation in the DNA banding pattern reveals differences among the individuals.

Question 4.
Write a detailed account of stem cells, types of stem cells and stem cell therapy?
Answer:
Our body is composed of over 200 specialised cell types, that can carry out specific functions, eg. Neurons or nerve cell that can transmit signals or heart cells which contract to pump blood or pancreatic cells to secrete insulin. These specialised cells are called differentiated cells. These specialised cells are called as differentiated cells. In contrast to differentiated cells, stem cells are the undifferentiated or unspecialised mass of cells. The stem cells are the cells of variable potency.
The two important properties of stem cells are:

  • its ability to divide and give rise to more stem cells by self-renewal,
  • its ability to give rise to specialised cells with specific functions by the process of differentiation.

Types of stem cells:

  1. Embryonic stem cells: These cells are extracted and cultured from the early embryos. These cells are derived from the inner cell mass of the blastocyst. These cells can be developed into any cell in the body.
  2. Adult stem cell or somatic stem cell: They are found in the neonatal (newborn) and adults. They have the ability to divide and give rise to specific cell types. The sources of adult stem cells are amniotic fluid, umbilical cord and bone marrow.
  3. Stem – cell therapy: Sometimes cells, tissues and organs in the body may be permanently damaged or lost due to genetic condition or disease or injury. In such situations, stem cells are used for the treatment of diseases, which is called stem cell therapy. In treating neurodegenerative disorders like Parkinson’s disease and Alzheimer’s disease neuronal stem cells can be used to replace the damaged or lost neurons.

Question 5.
(a) Explain genetically modified organisms |GMOs|.
(b) With the help of a tabular column tabulate the genetically modified plants and animals, with the objectives, gene inserted and achievement.
Answer:
(a) Genetic modification is the alteration or manipulation of genes in the organisms using rDNA techniques in order to produce the desired characteristics. The DNA fragment inserted is called transgene. Plants or animals expressing a modified endogenous gene or a foreign gene are also known as transgenic organisms.

The transgenic plants are much stable, with improved nutritional quality, resistant to diseases and tolerant to various environmental conditions. Similarly, transgenic animals are used to produce proteins of medicinal importance at low cost and improve livestock quality.

(b) Genetically modified plants and animals:
1. Genetically Modified Plants:

ObjectiveGene InsertedAchievement
Improved nutritional quality in RiceBeta carotene gene (In humans, Beta carotene is required for the synthesis of Vitamin A)Golden Rice (Genetically modified rice can produce beta carotene, that can prevent Vitamin A deficiency)
Increased crop productionBt gene from bacteria Bacillus thuringiensis. (Bt gene produces a protein that is toxic to insects)Insect resistant plants (These plants can produce the toxin protein that kills the insects which attack them)

2. Genetically Modified Animals:

ObjectiveGene insertedAchievement
The improved wool quality and productionGenes for synthesis of amino acid, cysteineTransgenic sheep (gene expressed)
Increased growth in fishesSalmon or Rainbow trout or Tilapia growth hormone geneTransgenic fish (gene expressed)

VII. Higher Order Thinking Skills (HOTS) Questions

Question 1.
Name the Indian scientist who is known for his leading role in India’s green revolution.
Answer:
Dr M. S. Swaminathan.

Question 2.
The application of biotechnology ‘A’ to treat a person born with a hereditary disease.
(a) What does ‘A’ mean?
(b) Mention its types.
Answer:
(a)

Question 5.
Rice normally grows well in alluvial soil, but _____ is a rice variety produced by mutation breeding that grows well in saline soil.
Answer:
Atomita – 2 rice

Question 6.
_____ technique made it possible to genetically engineer living organism.
Answer:
Recombinant DNA.

Question 7.
Restriction endonucleases cut the DNA molecule at specific positions known as ______.
Answer:
Molecular scissors.

Question 8.
Similar DNA fingerprinting is obtained for ______.
Answer:
Identical twins.

Question 9.
______ cells are undifferentiated mass of cells.
Answer:
Pleuripotent.

Question 10.
In gene cloning, the DNA of interest is integrated in a ______.
Answer:
Vector [plasmid].

III. State whether true or false. If false, write the correct statement.

Question 1.
Raphano brassica is a man – made tetraploid produced by colchicine treatment.
Answer:
True.

Question 2.
The process of producing an organism with more than two sets of chromosome is called mutation.
Answer:
False.
Correct statement: The process of producing an organism with more than two sets of chromosome is called polyploidy.

Question 3.
A group of plants produced from a single plant through vegetative or asexual reproduction are called a pureline.
Answer:
False.
Correct statement: A group of plants produced from a single plant through vegetative or asexual reproduction are called clones.

Question 4.
Iron fortified rice variety determines the protein quality of the cultivated plant.
Answer:
False.
Correct statement: Iron fortified rice variety determines the iron quality of the cultivated plant.

Question 5.
Golden rice is a hybrid.
Answer:
False.
Correct statement: Golden rice is a genetically modified plant.

Question 6.
Bt gene from bacteria can kill insects.
Answer:
True.

Question 7.
In vitro fertilisation means the fertilisation done inside the body.
Answer:
False.
Correct statement: In vitro fertilisation means the fertilisation done outside the body.

Question 8.
DNA fingerprinting technique was developed by Alec Jeffrey.
Answer:
True.

Question 9.
Molecular scissors refers to DNA ligases.
Answer:
False.
Correct statement: Molecular scissors refers to Restriction Enzymes.

IV. Match the following:

Question 1.

Column AColumn B
1. Sonalika(a) Phaseolus mungo
2. IR-8(b) Sugarcane
3. Saccharum(c) Semi-dwarf wheat
4. Mung No. 1(d) Groundnut
5. TMV-2(e) Semi-dwarf Rice
6. Insulin(f) Bacillus thuringienesis
7. Bt toxin(g) Beta carotene
8. Golden rice(h) the first hormone produced using rDNA technique

Answer:

  1. (c) Semi – dwarf wheat
  2. (e) Semi – dwarf Rice
  3. (b) Sugarcane
  4. (a) Phaseolus mungo
  5. (d) Groundnut
  6. (h) the first hormone produced using rDNA technique
  7. (f) Bacillus thuringienesis
  8. (g) Beta carotene.

V. Understand the assertion statement, justify the reason given and choose the correct choice:

(a) The assertion is correct and the reason is wrong.
(b) Reason is correct and the assertion is wrong.
(c) Both assertion and reason are correct.
(d) Both assertion and reason are wrong.

Question 1.
Assertion: Hybrid is superior to either of its parents.
Reason: Hybrid vigour is lost upon inbreeding.
Answer:
(a) The assertion is correct and the reason is wrong.

Question 2.
Assertion: Colchicine reduces the chromosome number.
Reason: It promotes the movement of sister chromatids to the opposite poles.
Answer:
(d) Both assertion and reason are wrong.

Question 3.
Assertion: rDNA is superior over hybridisation techniques.
Reason: Desired genes are inserted without introducing the undesirable genes in target organisms.
Answer:
(c) Both assertion and reason are correct.

VI. Answer in a Sentence

Question 1.
Give the name of the wheat variety having higher dietary fibre and protein.
Answer:
Atlas 66, a protein-rich variety, having higher dietary fibre and protein.

Question 2.
Semi-dwarf varieties were introduced in rice. This was made possible by the presence of dwarfing gene in rice. Name this dwarfing gene.
Answer:
Dee-geo-woo-gen a dwarf variety from China.

Question 3.
Define genetic engineering.
Answer:
Genetic engineering is the manipulation and transfer of genes from one organism to another organism to create a new DNA called recombinant DNA (rDNA). Genetic engineering is also called recombinant DNA technology.

Question 4.
Name the types of stem cells.
Answer:
Embryonic stem cells and somatic stem cells are the types of stem cells.

Question 5.
What are transgenic organisms?
Answer:
Plants or animals expressing a modified endogenous gene or a foreign gene are called transgenic organisms.

Question 6.
State the importance of biofertiliser.
Answer:
Biofertilizer adds nutrients through the natural process of nitrogen fixation, stimulate the plant growth through the synthesis of growth-promoting substance.

VII. Short Answer Questions

Question 1.
Discuss the method of breeding for disease resistance.
Answer:
Plant diseases are caused by pathogens like viruses, bacteria and fungi. This affects crop yield. To develop disease-resistant varieties of crops, that would increase the yield and reduce the use of fungicides and bactericides are important. Some disease-resistant varieties are as follows:

CropVarietyResistance to diseases
WheatHimgiriLeaf and stripe rust, hill bunt
CauliflowerPusa Shubhra, Pusa Snowball K-1Black rot
CowpeaPusa KomalBacterial blight

Question 2.
Name three improved characteristics of wheat that helped India to achieve high productivity.
Answer:
Sonalika, kalyan and sona are the three improved characteristic of wheat that helped India to achieve high productivity.

Question 3.
Name two maize hybrids rich in amino acid lysine.
Answer:
Protina, Shakti and Rathna are lysine – rich maize hybrids, which are developed in India.

Question 4.
Distinguish between
(a) Somatic gene therapy and germline gene therapy.
(b) Undifferentiated cells and differentiated cells.
Answer:
(a) Somatic gene therapy and germline gene therapy.

Somatic gene therapyGermline gene therapy
Somatic gene therapy is the replacement of the defective gene in somatic cells.Germline gene therapy is the replacement of the defective gene in the germ cell (egg and sperm).

(b) Undifferentiated cells and differentiated cells.

Undifferentiated cellsDifferentiated cells
Our body is composed of over 200 specialised cell types, that can carry out specific functions, eg. Neurons or nerve cells that can transmit signals. Pancreatic cells to secrete insulin. These specialised cells are called as differentiated cells.The cells which are variable potency, undifferentiated or unspecialised mass of cells are called stem cells. The stem cells are undifferentiated or unspecialised mass of cells.

Question 5.
State the applications of DNA fingerprinting technique.
Answer:
Applications of DNA Fingerprinting:
(i) DNA fingerprinting technique is widely used in forensic applications like crime investigation such as identifying the culprit. It is also used for paternity testing in case of disputes.
(ii) It also helps in the study of genetic diversity of population, evolution and speciation.

Question 6.
How are stem cells useful in the regenerative process?
Answer:
Sometimes cells, tissues and organs in the body may be permanently damaged or lost due to genetic condition or disease or injury. In such situations, stem cells are used for the treatment of diseases, which is called stem – cell therapy. In treating neurodegenerative disorders like Parkinson’s disease and Alzheimer’s disease neuronal stem cells can be used to replace the damaged or lost neurons.

Question 7.
Differentiate between outbreeding and inbreeding.
Answer:
Inbreeding:
When breeding or mating takes place between animals of the same breed, for about 4 – 6 generations, then it is called inbreeding. Superior males and superior females of the same breed are identified and mated in pairs. It helps in the accumulation of superior genes and the elimination of undesirable genes. Inbreeding depression is the continued inbreeding, which reduces fertility and productivity. Inbreeding exposes harmful recessive genes that are eliminated by selection.

Outbreeding:
The breeding of unrelated animals is outbreeding. The offsprings formed are called hybrids. The hybrids are stronger and vigorous than their parents. Cross between two different species with desirable features of economic value is mated. Mule is superior to the horse in strength, intelligence, ability to work and resistance to diseases, but they are sterile.

VIII. Long Answer Questions

Question 1.
What are the effects of hybrid vigour in animals.
Answer:

  1. Increased production of milk by cattle.
  2. Increased production of egg by poultry.
  3. High quality of meat is produced.
  4. Increased growth rate in domesticated animals.

Question 2.
Describe mutation breeding with an example.
Answer:
The mutation is defined as the sudden heritable change in the nucleotide sequence of DNA in an organism. The genetic variations brings out changes in an organism. The organism which undergoes mutation is called a mutant.
The factors which induce mutations are known as mutagens or mutagenic agents. The mutagens are of two types:
(a) Physical mutagens: Radiations like X – rays, a, P and Y – rays, UV rays and temperature, etc, which induce, maturations are called physical mutagens.

(b) Chemical mutagens: Chemical substances that induce mutations are called chemical mutagens, eg. Mustard gas and nitrous acid. The utilization of induced mutation in crop improvement is called mutation inbreeding.
Achievements of mutation breeding:

  • Sharbati Sonora wheat produced from Sonora – 64 by using gamma rays.
  • Atomica – 2 rice with saline tolerance and pest resistance.
  • Groundnuts with thick shells.

Question 3.
Biofortification may help in removing hidden hunger. How?
Answer:
Biofortification: Biofortification is the scientific process of developing crop plants enriched with high levels of desirable nutrients like vitamins, proteins and minerals. Some examples of crop varieties developed as a result of biofortification are given below:

  1. Protina, Shakti and Rathna are lysine rich maize hybrids (developed in India).
  2. Atlas 66, a protein rich wheat variety.
  3. Iron rich fortified rice variety’.
  4. Vitamin A enriched carrots, pumpkin and spinach.

Question 4.
With a neat labelled diagram explain the techniques involved in gene cloning.
Answer:
The carbon copy or more appropriately, a clone means to make a genetically exact copy of an organism. ‘Dolly’ is the cloned sheep.

In gene cloning, a gene or a piece of DNA fragment is inserted into a bacterial cell, where DNA will be multiplied (copied) as the cell divides.
The basic steps involved in gene cloning are:

  • Isolation of desired DNA fragment by using restriction enzymes.
  • Insertion of the DNA fragment into a suitable vector (plasmid) to make rDNA.
  • Transfer of rDNA into the bacterial host cell (Transformation).
  • Selection and multiplication of the recombinant host cell to get a clone.
  • Expression of the cloned gene in the host cell.

Using this strategy several enzymes, hormones and vaccines can be produced.

Question 5.
Discuss the importance of biotechnology in the field of medicine.
Answer:
Using genetic engineering techniques medicinally important valuable proteins or polypeptides that form the potential pharmaceutical products for the treatment of various diseases have been developed on a commercial scale.
Pharmaceutical products developed by rDNA technique:

  1. Insulin used in the treatment of diabetes.
  2. Human growth hormone used for treating children with growth deficiencies.
  3. Blood clotting factors are developed to treat haemophilia.
  4. Tissue plasminogen activator is used to dissolve blood clots and prevent heart attack.
  5. Development of vaccines against various diseases like Hepatitis B and rabies.

IX. Higher Order Thinking Skills (HOTS) Questions

Question 1.
A breeder wishes to incorporate desirable characters into the crop plants. Prepare a list of characters he will incorporate.
Answer:
The list of character he will incorporate are:

  1. High yielding and better quantity
  2. Disease resistance
  3. Insects pest resistance
  4. Improved nutritional quality
  5. Short duration

Question 2.
Organic farming is better than Green Revolution. Give reasons.
Answer:

  • Dwarfness is desired in cereals, so fewer nutrients are consumed by the crops.
  • Fertilizer is responsive.
  • Disease resistant varieties.
  • Insect and pest resistant crop varieties.
  • High levels of desirable nutrients like vitamins, proteins and minerals.

Question 3.
Polyploids are characterised by gigantism. Justify your answer.
Answer:
An organism having more than two set of chromosome is called polyploidy. It can be induced by physical agents such as heat or cold treatment, X-rays and chemical agents like colchicine. As organisms produced by polyploidy have more than two set of chromosomes they are gigantic.

Question 4.
‘P’ is a gene required for the synthesis of vitamin A. It is integrated with the genome of ‘Q’ to produce genetically modified plant ‘R’.
(i) What is P, Q and R?
(ii) State the importance of ‘R’ in India.
Answer:
(i)  The P, Q and R:

  • P – Beta – carotene gene.
  • Q – Prevent vitamin A deficiency.
  • R – Golden rice.

(ii) Importance of rice in India:

  • Rice is the most important staple food for millions of people in developing countries like India.
  • Beta – carotene is produced in the endosperm of the grain. It could control the chronic health problems caused by vitamin A deficiency, especially among the poor in developing countries like India.

Samacheer Kalvi 10th Science Breeding and Biotechnology

Additional Questions Solved

I. Fill in the blanks.

Question 1.
Plant ______ is the art of developing economically important plants.
Answer:
Breeding.

Question 2.
Plant diseases are caused by ______ like viruses, bacteria and fungi.
Answer:
Pathogen.

Question 3.
______ is the first man – made cereal hybrid.
Answer:
Triticale.

Question 4.
The superiority of the hybrid obtained by cross-breeding is called _____ or ______.
Answer:
Heterosis
or
Hybrid vigour.

Question 5.
The other name for genetic engineering is ______.
Answer:
Recombinant DNA technology.

Question 6.
The organism which undergoes mutation is called a ______ and the factors which induce mutations are ______.
Answer:
Mutant; mutagenic agents.

Question 7.
The replacement of the defective gene in a germ cell (egg or sperm) is called ______.
Answer:
Germline gene therapy.

Question 8.
Blood clotting factors are developed to treat ______.
Answer:
Haemophilia.

Question 9.
Stem cells, which are undifferentiated or unspecialised mass of cells can be used for the treatment is called ______.
Answer:
Stem cell therapy.

Question 10.
_______ is used in the treatment of diabetes.
Answer:
Insulin.

II. Match the following:

Question 1.

1. Cowpea(a) Joining the DNA fragments
2. UV rays(b) New breed of sheep
3. Lady’s finger(c) Bacterial blight
4. DNA ligase(d) Flat bean
5. Pusasem 3(e) Pusa Sawani
6. Hissardale(f) Induce mutation

Answer:
1. (c) Bacterial blight
2. (f) Induce mutation
3. (e) Pusa Sawani
4. (a) Joining the DNA fragments
5. (d) Flat bean
6. (b) New breed of sheep.

III. Write “True or False” statements. Correct the false statements:

Question 1.
Modem Agricultural practices are activities carried out to improve the plants.
Answer:
True.

Question 2.
When breeding takes place between animals of the same breed, it is called outbreeding.
Answer:
False.
Correct statement: When breeding takes place between animals of the same breed, it is called inbreeding.

Question 3.
The process of introducing high yielding varieties of plants from one place to another is called a selection.
Answer:
False.
Correct statement: The process of introducing high yielding varieties of plants from one place to another is called Exotic species.

Question 4.
The mutation is a sudden inheritable change in the nucleus sequence of DNA in an organism.
Answer:
False.
Correct statement: Mutation is a sudden heritable change in the nucleotide sequence of DNA in an organism.

Question 5.
A breed is a group of animals of common origin within a species, which has certain characters, that are not found in other members of the same species.
Answer:
True.

IV. Choose the correct answer.

Question 1.
The high yielding rice variety from Indonesia and China are ______.
(a) Peta and DGWG
(b) IR-8 and Gold rice
(c) Hexaploid Triticale and Triticum durum
(d) Sonalika and Kalyan Sona.
Answer:
(a) Peta and DGWG

Question 2.
First artificially synthesized hormone is:
(a) Secretin
(b) Insulin
(c) Glucagon
(d) Renin
Answer:
(b) Insulin

Question 3.
The presence of this substance in bacteria can undergo replication independently along with chromosomal DNA ______.
(a) heritable
(b) colchicine
(c) mutation
(d) plasmid.
Answer:
(d) plasmid.

Question 4.
Bacillus thuringiensis (Bt) stains have been used for designing novel.
(a) Bio-metallogical techniques
(b) Bio-insecticidal plants
(c) Bio-mineralization
(d) Bio-fertilizer
Answer:
(b) Bio-insecticidal plants

Question 5.
A group of plants produced from a single plant through vegetative or asexual reproduction is called ______.
(a) Transgenic
(b) Hexaploid
(c) clones
(d) mutation.
Answer:
(b) Hexaploid

V. Answer the following briefly:

Question 1.
What is the green revolution? Who is the “Father of Green Revolution”?
Answer:
Green Revolution is the process of increasing food production through high yielding crop varieties and modem agricultural techniques in underdeveloped and developing nations. Dr Norman. E. Borlaug, an American agronomist is the “Father of Green Revolution”.

Question 2.
Write the role of polyploidy in crop improvement.
Answer:
The role of polyploidy in crop improvement are production of:

  1. Seedless watermelons (3n) and bananas (3n).
  2. TV-29 (triploid variety of tea) with larger shoots and drought tolerance.
  3. Triticale (6n) is a hybrid of wheat and rye. To make this plant fertile polyploidy is induced. It has higher dietary fibre and protein.
  4. Raphanobrassica is an allotetraploid by colchicine treatment.

Question 3.
What is Bio – fortification? Give any two examples.
Answer:
Bio – fortification is the scientific process of developing crop plants enriched with high levels of desirable nutrients like vitamins, proteins and minerals.
Examples of crop varieties developed as a result of bio – fortification are:

  • Protina, Shakti and Rathna are lysine – rich maize hybrids.
  • Atlas 66, A protein – rich wheat variety.

Question 4.
Give two examples of cross-breeding in animals.
Answer:
Cross breed of fowls: White Leghorn X Plymouth Rock

Hybrid fowl – yield more eggs

Cross breed of cows : Developed by mating the bulls of exotic breeds and cows of indigenous breeds.
Brown Swiss X Sahiwal

Karan Swiss – yield 2-3 times more milk than indigenous cows.

Question 5.
What is hybridization? Explain the hybridization experiment.
Answer:
The process of crossing two or more types of plants for bringing their desired characters together into one progeny hybrid is called hybridization. Hybridization is creating a genetic variation to get improved varieties.

Hybridization Experiment:
Triticale is the first man-made cereal hybrid. It is obtained by crossing wheat (Triticum durum, 2n = 28) and rye (Secale cereal, 2n = 14). The F, a hybrid is sterile (2n = 21). Then the chromosome number is doubled using colchicine and it becomes hexaploid triticale (2n = 42). The cycle of crop raising and selection continues until the plants with the desired characters are finally obtained.

Question 6.
Name the methods of plant breeding for crop improvement.
Answer:
The methods of plant breeding to develop high yielding varieties, for crop improvement, are as follows:

  • Introduction of new varieties of plants
  • Selection
  • Polyploid breeding
  • Mutation breeding
  • Hybridization.

Question 7.
Explain briefly about gene therapy.
Answer:
The replacement of a defective gene by the direct transfer of functional genes into humans to treat genetic disease or disorder is referred to as gene therapy.
The recombinant DNA technology is used for gene therapy:

  • Somatic gene therapy is the replacement of the defective gene in somatic cells.
  • Gene line gene therapy is the replacement of the defective gene in the germ cell (egg or sperm).

Question 8.
What were the important discoveries that led to the stepping stones of recombinant DNA technology?
Answer:

  1. Presence of plasmid in bacteria that can undergo replication independently along with chromosomal DNA.
  2. Restriction enzymes cuts or break DNA at specific sites and are also called as molecular scissors.
  3. DNA ligases are the enzymes which help in ligating (joining) the broken DNA fragments.

Question 9.
What does modern agriculture include?
Answer:
Modem agricultural practices are activities carried out to improve the cultivation of plants. It includes:

  1. Preparation of soil
  2. Sowing
  3. Application of manures and fertilizers
  4. Proper irrigation
  5. Protection from weeds and pests
  6. Harvesting and threshing
  7. Storage

Question 10.
What is the aim of crop improvement?
Answer:
The aim of crop improvement is to develop improved crop varieties possessing higher yield, better quality, resistance to diseases and shorter duration.

Question 11.
(a) What are the two important properties of stem cells?
(b) Write a short note on two types of stem cells.
Answer:
(a) Properties of stem cells:
It’s the ability to divide and give rise to more stem cells by self-renewal.
It’s the ability to give rise to specialised cells with specific functions by the process of differentiation.

(b) Types of cells:

  • Embryonic stem cells: Embryonic stem cells are derived from the inner cell mass of the blastocyst, which can be extracted from the early embryos. These cells can be developed into any cell in the body.
  • Adult stem cell or somatic stem cell: These cells are found in the newborn and adults. They have the ability to divide and give rise to specific cell types. Sources of adult stem cells are amniotic fluid, umbilical cord and bone marrow.

Question 12.
What are bulk genomic DNA and satellite DNA?
Answer:
In human beings, 99 % of the DNA base sequences are the same and this is called a bulk genomic DNA. The remaining 1 % of the DNA sequence differs from one individual to another. This 1 % DNA sequence is present as a small stretch of repeated sequences, which is called satellite DNA.

VI. Answer the following in detail.

Question 1.
What are stem cells? Explain its types ooooo.
Answer:
Stem cells are undifferentiated or unspecialised mass of cells. The stem cells are the cells of variable potency. The two important properties of stem cells that differentiate them from other cells are:

  1. Its ability to divide and give rise to more stem cells by self-renewal.
  2. Its ability to give rise to specialised cells with specific functions by the process of differentiation.

Types of stem cells Embryonic stem cells can be extracted and cultured from the early embryos. These cells are derived from the inner cell mass of the blastocyst. These cells can be developed into air, cell in the body.

Adult stem cell or somatic stem cell are found in the neonatal (new bom) and adults. They have tne ability to divide and give rise to specific cell types. Sources of adult stem cells are amniotic fluid, umbilical cord and bone marrow.

Question 2.
Explain with examples the inbreeding and outbreeding of animal breeding.
Answer:
Animal breeding aims at the genotypes of domesticated animals to increase their yield and improve the desirable qualities to produce milk, egg and meat. When breeding takes place between animals of the same breed, it is called inbreeding.
The cross between different – breeds is called outbreeding.

1. Inbreeding:
Inbreeding refers to the mating of closely related animals within the same breed for about 4 – 6 generations. Superior males and superior females of the same breed are identified and mated in pairs. It helps in the accumulation of superior genes and elimination of genes, which are undesirable. Hissardale is a new breed of sheep developed in Punjab by crossing Bikaneri (Magra) ewes and Australian Marino rams.

2. Inbreeding depression:
Continued inbreeding reduces fertility and productivity. Inbreeding exposes harmful recessive genes that are eliminated by selection.

3. Outbreeding:
It is the breeding of unrelated animals. The offsprings formed are called hybrids. The hybrids are stronger and vigorous than their parents. Cross between two different species with desirable features of economic value are mated. Let’s see what cross produce a mule. Mule is superior to a horse in strength, intelligence, ability to work and resistance to diseases but they are sterile

Question 3.
Explain the DNA fingerprinting technology with an illustration.
Answer:
The DNA pattern of two individuals cannot be the same except for identical twins. Each persons DNA sequence is unique, due to the small difference in the base pairs. DNA fingerprinting is the easier and quicker method, to compare the genetic difference among the two individuals. This technique was developed by Alec Jeffrey.

Each individual’s unique DNA sequences provides distinct characteristics of an individual, which helps in identification. A variable number of tandem repeat sequences [VNTRs] serve as molecular markers for identification.

In human beings, 99 % of DNA base sequences are the same and this is called as bulk genomic DNA. The remaining 1 % DNA sequence differs from one individual to another. This 1 % DNA sequence is present as a small stretch of repeated sequences which is called as satellite DNA. The number of copies of the repeat sequence also called VNTRs differs from one individual to another and results in variation in the size of the DNA segment.

As shown in the illustration, the sequence AGCT is repeated six times in the first person, five times in the second person and seven times in the third person. Because of this, the DNA segment of the third person will be larger in size followed by a DNA segment of first – person and then the second person. Thus it is clear that satellite DNA brings about variation within the population. Variation in the DNA banding pattern reveals differences among the individuals.

Question 4.
Write a detailed account of stem cells, types of stem cells and stem cell therapy?
Answer:
Our body is composed of over 200 specialised cell types, that can carry out specific functions, eg. Neurons or nerve cell that can transmit signals or heart cells which contract to pump blood or pancreatic cells to secrete insulin. These specialised cells are called differentiated cells. These specialised cells are called as differentiated cells. In contrast to differentiated cells, stem cells are the undifferentiated or unspecialised mass of cells. The stem cells are the cells of variable potency.
The two important properties of stem cells are:

  • its ability to divide and give rise to more stem cells by self-renewal,
  • its ability to give rise to specialised cells with specific functions by the process of differentiation.

Types of stem cells:

  1. Embryonic stem cells: These cells are extracted and cultured from the early embryos. These cells are derived from the inner cell mass of the blastocyst. These cells can be developed into any cell in the body.
  2. Adult stem cell or somatic stem cell: They are found in the neonatal (newborn) and adults. They have the ability to divide and give rise to specific cell types. The sources of adult stem cells are amniotic fluid, umbilical cord and bone marrow.
  3. Stem – cell therapy: Sometimes cells, tissues and organs in the body may be permanently damaged or lost due to genetic condition or disease or injury. In such situations, stem cells are used for the treatment of diseases, which is called stem cell therapy. In treating neurodegenerative disorders like Parkinson’s disease and Alzheimer’s disease neuronal stem cells can be used to replace the damaged or lost neurons.

Question 5.
(a) Explain genetically modified organisms |GMOs|.
(b) With the help of a tabular column tabulate the genetically modified plants and animals, with the objectives, gene inserted and achievement.
Answer:
(a) Genetic modification is the alteration or manipulation of genes in the organisms using rDNA techniques in order to produce the desired characteristics. The DNA fragment inserted is called transgene. Plants or animals expressing a modified endogenous gene or a foreign gene are also known as transgenic organisms.

The transgenic plants are much stable, with improved nutritional quality, resistant to diseases and tolerant to various environmental conditions. Similarly, transgenic animals are used to produce proteins of medicinal importance at low cost and improve livestock quality.

(b) Genetically modified plants and animals:
1. Genetically Modified Plants:

ObjectiveGene InsertedAchievement
Improved nutritional quality in RiceBeta carotene gene (In humans, Beta carotene is required for the synthesis of Vitamin A)Golden Rice (Genetically modified rice can produce beta carotene, that can prevent Vitamin A deficiency)
Increased crop productionBt gene from bacteria Bacillus thuringiensis. (Bt gene produces a protein that is toxic to insects)Insect resistant plants (These plants can produce the toxin protein that kills the insects which attack them)

2. Genetically Modified Animals:

ObjectiveGene insertedAchievement
The improved wool quality and productionGenes for synthesis of amino acid, cysteineTransgenic sheep (gene expressed)
Increased growth in fishesSalmon or Rainbow trout or Tilapia growth hormone geneTransgenic fish (gene expressed)

VII. Higher Order Thinking Skills (HOTS) Questions

Question 1.
Name the Indian scientist who is known for his leading role in India’s green revolution.
Answer:
Dr M. S. Swaminathan.

Question 2.
The application of biotechnology ‘A’ to treat a person born with a hereditary disease.
(a) What does ‘A’ mean?
(b) Mention its types.
Answer:


(a) Gene therapy refers to the replacement of defective gene.
(b) The two type of gene therapy are Somatic and Germline.

Question 3.
Write the crossbreeds of the following:
(a) Crossbreed of fowls
(b) Crossbreed of cows
Answer:


(a) A crossbreed of fowls:

  • White Leghorn × Plymouth Rock

    Hybrid fowl – yield more eggs

(b) A crossbreed of cows:

  • Brown Swiss × Sahiwal

    Karan Swiss [yield 2 – 3 times more milk than indigenous cows]

Gene therapy refers to the replacement of defective gene.
(b) The two type of gene therapy are Somatic and Germline.

Question 3.
Write the crossbreeds of the following:
(a) Crossbreed of fowls
(b) Crossbreed of cows
Answer:
(a) A crossbreed of fowls:

  • White Leghorn × Plymouth Rock

    Hybrid fowl – yield more eggs

(b) A crossbreed of cows:

  • Brown Swiss × Sahiwal

    Karan Swiss [yield 2 – 3 times more milk than indigenous cows]

Samacheer, Kalvi, 10th, sslc, Science, Solutions, Chapter 19, Origin and Evolution of Life, tamilnadu board, biology,

I. Choose the Correct Answer.

Question 1.
Biogenetic law states that _____.
(a) Ontogeny and phylogeny go together.
(b) Ontogeny recapitulates phylogeny.
(c) Phylogeny recapitulates ontogeny.
(d) There is no relationship between phylogeny and ontogeny.
Answer:
(b) Ontogeny recapitulates phylogeny.

Question 2.
The ‘use and disuse theory’ was proposed by _____.
(a) Charles Darwin
(b) Ernst Haeckel
(c) Jean Baptiste Lamarck
(d) Gregor Mendel.
Answer:
(c) Jean Baptiste Lamarck

Question 3.
Paleontologists deal with _____.
(a) Embryological evidences
(b) Fossil evidences
(c) Vestigial organ evidences
(d) All the above.
Answer:
(b) Fossil evidences

Question 4.
The best way of direct dating fossils of recent origin is by _____.
(a) Radio – carbon method
(b) Uranium lead method
(c) Potassium – argon method
(d) Both (a) and (c).
Answer:
(a) Radio – carbon method

Question 5.
The term Ethnobotany was coined by _____.
(a) Khorana
(b) J.W. Harshberger
(c) Ronald Ross
(d) Hugo de Vries.
Answer:
(b) J.W. Harshberger

II. Fill in the blanks.

Question 1.
The characters developed by the animals during their life time, in response to the environmental changes are called _____.
Answer:
Acquired characters.

Question 2.
The degenerated and non-functional organs found in an organism are called _____.
Answer:
Vestigial organ.

Question 3.
The forelimbs of bat and human are examples of ______ organs.
Answer:
Homologous.

Question 4.
The theory of natural selection for evolution was proposed by _____.
Answer:
Charles Darwin.

III. State whether True or False. If false, write the correct statement.

Question 1.
‘The use and disuse theory of organs’ was postulated by Charles Darwin?
Answer:
False.
Correct statement: ‘The use and disuse theory of organs’ was postulated by Jean Baptiste Lamarck.

Question 2.
The homologous organs look similar and perform similar functions but they have different origin and developmental pattern?
Answer:
False.
Correct statement: The homologous organs look dissimilar and perform dissimilar functions, but they have the same origin and developmental pattern.

Question 3.
Birds have evolved from reptiles.
Answer:
True.

IV. Match the following:

Question 1.

Column AColumn B
1. Atavism(a) caudal vertebrae and vermiform appendix
2. Vestigial organs(b) a forelimb of a cat and a bat’s wing
3. Analogous organs(c) rudimentary tail and thick hair on the body
4. Homologous organs(d) a wing of a bat and a wing of an insect
5. Wood park(e) radiocarbon dating
6. W.F. Libby(f) Thiruvakkarai

Answer:

  1. (c) rudimentary tail and thick hair on the body
  2. (a) caudal vertebrae and vermiform appendix
  3. (d) a wing of a bat and a wing of an insect
  4. (b) a forelimb of a cat and a bat’s wing
  5. (f) Thiruvakkarai
  6. (e) radiocarbon dating.

V. Answer in a word or Sentence

Question 1.
A human hand, a front leg of a cat, a front flipper of a whale and a bat’s wing look dissimilar and adapted for different functions. What is the name given to these organs?
Answer:
Homologous organs.

Question 2.
Which organism is considered to be the fossil bird?
Answer:
Fossil bird Archaeopteryx.

Question 3.
What is the study of fossils called?
Answer:
Palaeontology.

VI. Short Answers Questions

Question 1.
The degenerated wing of a kiwi is an acquired character. Why is it an acquired character?
Answer:
Kiwi does not have the need to fly that is why they do not have wings. The characters developed by the animals during their life in response to environmental changes. The vestigial wings are so small (invisible) under the bristly, hair-like two-branched feathers. So the degenerated wing of a kiwi is an acquired character.

Question 2.
What is the study of fossils called?
Answer:
Palaeontology is called as the study of fossils.

Question 3.
Define Ethnobotany and write its importance.
Answer:
Ethnobotany is the study of a region’s plants and their practical uses through the traditional knowledge of the local culture of people.
Importance of Ethnobotany:

  • It provides traditional uses of the plant.
  • It gives information about certain unknown and known useful plants.
  • The ethnomedicinal data will serve as a useful source of information for the chemists, pharmacologists and practitioners of herbal medicine.
  • Tribal communities utilize ethnomedicinal plant parts like bark, stem, roots, leaves, flowers, flower bud, fruits, seeds, oils, resins, dyes and gum for the treatment of diseases like diarrhoea, fever, headache, diabetes, jaundice, snakebites and leprosy, etc.

Question 4.
How can you determine the age of the fossils?
Answer:
The age of fossils is determined by radioactive elements present in it. They may be carbon, uranium, lead or potassium.

VII. Long Answer Questions

Question 1.
Natural selection is a driving force for evolution-How?
Answer:
Darwin published his observations under the name “origin of species”. It elaborates on the theory of natural selection for evolutionary transformation.
The principles of Darwinism tells that natural selection is a driving force for evolution.

1. Overproduction: Living beings have the ability to reproduce and have the capacity to multiply in a geometrical manner.

2. Struggle for existence: Due to overproduction, a geometric ratio of increase in population occurs. The space to live and food available for the organisms remain the same. This creates a competition among the organisms, for food and space, leading to struggle.

  • The competition may be among the individuals of the same species (Intraspecific struggle).
  • Competition between the organisms of different species living together (Interspecific struggle).
  • Natural conditions like extreme heat or cold drought and floods can affect the existence of organisms (Environmental struggle).

3. Variations: Small variations are important for evolution. According to Darwin, favourable variations are useful to the organisms and unfavourable variations are harmful or useless to the organisms.

4. Survival of the fittest or Natural selection: During the struggle for existence, the organisms which can overcome the challenging situation, survive and adapt to the surrounding environment. Organisms, which are unable to face the challenges, are unfit to survive and disappear. The process of selection of organisms with favourable variation is called Natural selection.

5. Origin of species: According to Darwin, new species originates by the gradual accumulation of favourable variations for a number of generations.

Question 2.
How do you differentiate homologous organs from analogous organs?
Answer:

Homologous organsAnalogous organs
1. The homologous organs have been inherited from common ancestors, with similar developmental pattern in embryos.1. Analogous structures are shown in a batwing, a bird wing and an insect wing.
2. The forelimbs of a human hand, a front leg of a cat, the flipper of a whale and a bat’s, wing look dissimilar and adapted for different functions.2. The analogous organs look similar but perform similar functions.
3. Their mode of development and the basic structure of bone are similar.3. They have a different origin. Wings of insect are membranous extensions whereas wings of a bat is a bony structure. But performing the same function of flying.

Question 3.
How does fossilization occur in plants?
Answer:
A plant fossil is any preserved part of a plant that has died long back. Fossils may be a prehistoric impression that may be hundred to millions of years old. Majority of the plant fossils are disarticulated parts of plants, it is rare to find plants to be preserved as whole.

VIII. Higher Order Thinking Skills (HOTS) Questions

Question 1.
Arun was playing in the garden. Suddenly he saw a dragonfly sitting on a plant. He observed the wings of it. He thought it looked similar to a wing of a crow. Is he correct? Give a reason for your answer.
Answer:
No. He is not correct. Both crow and dragonfly have the same function of flying with wings. But it’s the origin (basic structure) is different. Dragonfly wing is the membranous extension. But the wing of the crow is the modification of forelimb.

Question 2.
Imprints of fossils tell us about evolution- How?
Answer:
Fossil records show that evolution has taken a gradual process from simple to complex organisms. The study of fossils helps us to understand the link of evolution. The origin of modem birds is supported by the evidence of palaeontology.

Question 3.
Octopus, cockroach and frog all have eyes. Can we group these animals together to establish a common evolutionary origin? Justify your answer.
Answer:
Convergent evolution is the process, by which the independently evolved features, may similar to each other, but can arise through different developmental pathways. So the octopus, cockroach and frog all have eyes. The independently evolved eye may similar in each other, but can arise through different developmental pathways.

Samacheer Kalvi 10th Science Origin and Evolution of Life Additional Questions Solved

I. Fill in the blanks.

Question 1.
The history of life has two aspects namely ______ and ______.
Answer:
Origin of life; The evolution of life.

Question 2.
The theory which postulates that life originates from pre – existing life is ______.
Answer:
Biogenesis.

Question 3.
_____ is the gradual change occurring in living organisms over a period of time.
Answer:
Evolution.

Question 4.
Sexual reproduction, which involves meiosis helps in the recombination of ______ during gametic fusion.
Answer:
Genes.

Question 5.
The major concept in astrobiology is the ______.
Answer:
Habitable zone.

Question 6.
The organisms, which live in extreme environmental conditions on Earth are called ______.
Answer:
Extremophiles.

Question 7.
Fossil records show that evolution has taken a gradual process from simple to _______ organisms.
Answer:
Complex.

II. Match the following:

Question 1.

1. Big Bang theory(a) study of regions and practical use of plants
2. Petrifaction(b) organisms buried and cause depression
3. Archaeopteryx(c) other names for astrobiology
4. Ethnobotany(d) preserve hard and soft parts
5. Mould(e) origin of the universe
6. Exobiology(f) fossil bird

Answer:

  1. (e) origin of the universe
  2. (d) preserve hard and soft parts
  3. (f) fossil bird
  4. (a) study of regions and practical use of plants
  5. (b) organisms buried and cause depression
  6. (c) other names for astrobiology.

Question 2.

1. Oparin and Haldane(a) use and disuse theory
2. Ernest Haeckel(b) Mutation theory
3. Leonardo da Vinci(c) Father of Indian palaeobotany
4. Jean Baptiste Lamarck(d) Life from the chemical reaction
5. Darwin(e) Father of palaeontology
6. De Vries(f) Radioactive carbon
7. Birbal Sahni(g) Ethnobotany
8. W.F. Libby(h) Origin of species
9. J.W. Harshberger(i) Biogenetic law

Answer:

  1. (d) Life from a chemical reaction
  2. (i) Biogenetic law
  3. (e) Father of palaeontology
  4. (a) use and disuse theory
  5. (h) Origin of species
  6. (b) Mutation theory
  7. (c) Father of Indian palaeobotany
  8. (f ) Radioactive carbon
  9. (g) Ethnobotany.

III. Choose the correct answer.

Question 1.
The theory of idea embodies that life on Earth is a divine creation ______.
(a) chemical reaction
(b) special creation
(c) spontaneous generation
(d) Biogenesis.
Answer:
(b) special creation

Question 2.
Palaeontology deals with the study of ______.
(a) analogous organs
(b) fossils
(c) gradual change
(d) homologous organ.
Answer:
(c) gradual change

Question 3.
The other name for continuous variation is ______.
(a) germinal variation
(b) somatic variation
(c) discontinuous variation
(d) fluctuating variation.
Answer:
(d) fluctuating variation.

Question 4.
It is a branch of palaeontology that deals with the recovery and identification of plant remain of geological past ______.
(a) palaeobotany
(b) Embryology
(c) mutation
(d) palaeontology.
Answer:
(a) palaeobotany

Question 5.
Book ‘Philosophic Zoologique’ published in the year 1809 was written by:
(a) Darwin
(b) Lamarck
(c) Wallace
(d) Mendel
Answer:
(b) Lamarck

IV. Answer the following shortly.

Question 1.
What is Abiogenesis?
Answer:
Abiogenesis or spontaneous generation theory states that life originated spontaneously from lifeless matter. It was believed that fishes originated from mud, frogs from moist soil and insects from decaying matter.

Question 2.
What is the cosmic origin?
Answer:
Cosmic origin of extraterrestrial theories states that life came from outer space. The unit of life called spores (panspermia) were transferred to different planets including Earth.

Question 3.
What is the chemical evolution of life?
Answer:
Chemical evolution of life theory states that life arose by a series of sequential chemical reactions. The first form of life could have come from pre – existing non – living inorganic molecules, which gave rise to the formation of diverse organic molecules, which are transformed into a colloid system to produce life.

Question 4.
Name the evidence of evolution What do they support?
Answer:

  • Evidence from morphology and Anatomy.
  • Evidence from embryology.
  • Evidence from palaeontology.

Evolution is best understood by observing the relationship between the existing organisms and the similarities of the extinct organisms. This evidence supports the concept that all organisms have evolved from common ancestors.

Question 5.
Explain the evidence of evolution from Embryology.
Answer:
The embryos from fish to mammals are similar in their early stages of development. The study of comparative embryology of different animals supports the concept of evolution. The differentiation of their special characters appears in the later stages of development. Ontogeny recapitulates phylogeny. The stages of development of the individual animal repeat the evolutionary history of the entire race of the animal.
Samacheer Kalvi 10th Science Solutions Chapter 19 Origin and Evolution of Life 1

Question 6.
Represent a flow chart showing the postulates of Lamarckism?
Answer:
The postulates of Lamarckism:

Question 7.
Explain the evidence of evolution from palaeontology.
Answer:
Palaeontology deals with the study of fossils. The study of fossils helps us to understand the line of evolution of many invertebrates and vertebrates. Fossil records show that evolution has taken a gradual process from simple to complex organisms.

The origin of modem birds is supported by the evidence from palaeontology. Archaeopteryx is the oldest known fossil bird. It is considered to be a connecting link between reptiles and birds. It had wings with feathers, like a bird. It had a long tail, clawed digits and conical teeth like a reptile.

Question 8.
What is evolution?
Answer:
Formation of new species due to changes in specific characters over several generations as a response to natural selection is called evolution. Evolution is the gradual change occurring in living organisms over a period of time.

Question 9.
Represent a flow chart showing the postulates of Darwinism?
Answer:
The postulates of Darwinism:

Question 10.
Explain the types of variation?
Answer:
Variations are the differences found among individuals of the same species and the offspring of the same parent. New species originate by the gradual accumulation of variations. Evolution would not be possible without variation.
Somatic variation and germinal variation are the two types of variations:

  1. Somatic variation: The variation which affects the body (somatic) cells of the organisms are called somatic variation, which is not heritable. They occur due to environmental factors.
  2. Geminal variation: The variations, which are produced in germ cells and inherited are called germinal variation. They are classified into two types.
    • Continuous variation: Small variations which occur among individuals of a population, and occur by gradual accumulation is called continuous variation. They are also called fluctuating variation, e.g. skin colour, height and weight and colour of the eye, etc.
    • Discontinuous variation: These changes are sudden, which occur in an organism, due to mutations. These large variations are not useful for evolution, e.g. short – legged Ancon sheep and six or more digits (fingers) in human, etc.

Question 11.
Explain the importance of fossils?
Answer:
Importance of fossils:

  1. They throw light on phylogeny and evolution of plants.
  2. Fossil plants give a historical approach to the plant kingdom.
  3. Fossils are useful in the classification of plants.
  4. Fossil plants can be used in the field of descriptive and comparative anatomy.

Question 12.
What are Extremophiles?
Answer:
The organisms which live in extreme environmental conditions on Earth are called extremophiles within our own solar system, there are many areas that are different from the Earth. We may find the presence of life similar to extremophile bacteria.

Question 13.
What is Astrobiology or Exobiology? What does it deal?
Answer:
Astrobiology or exobiology is the science which looks for the presence of extraterrestrial in the universe.
Astrobiology deals with the origin, evolution and distribution of life in the universe and to investigate the possibility of living in another world.

The major concept in astrobiology is the habitable zone. Astrobiology explains that any planets can support the existence of life if it fulfils two criteria:

  • It must have the right mass to retain an atmosphere.
  • It must have an orbit at the right distance from Sun, that it allows liquid water to exist. The distance needs to be neither too hot nor too cold and is often called the Goldilocks zone for life.

V. Answer the following in detail.

Question 1.
Explain in detail with diagrams, the evidence of evolution, through morphology and anatomy.
Answer:
The comparative study of morphology and anatomy of organisms have evolved from a common ancestor.

(ii) Analogous organs: The analogous organs look similar and perform similar functions but they have different origin and developmental pattern. The function of the wings of a bat, the wings of a bird and wings of an insect are similar, but their basic structures are different.

(iii) Vestigial organs: The degenerated and non¬functional organs of animals are called vestigial organs. The same organs are found to be well- developed and functional, in some of the related forms. Some of the vestigial organs in man are a vermiform appendix, nictitating membrane, caudal vertebra and coccyx, etc.

(iv) Atavism: The reappearance of ancestral characters in some individuals is called atavism, e.g. Presence of rudimentary tail in newborn babies, the presence of thick hair on the human body.

Question 2.
(a) Name the popular names of Lamarckism.
(b) Explain the principles of Lamarckism.
Answer:
(a) Lamarckism is the hypothesis that an organism can pass on characteristics, that it has acquired through use or disuse, during it’s lifetime to the offspring. Lamarck’s theory of evolution was published in ‘Philosophic Zoologique’ in the year 1809. Lamarckism is popularly known as ‘Theory of inheritance of Acquired Characters” or “Use and Disuse theory”

(b) (i) internal vital force: Due to the inherent ability of the living organisms or their component parts tend to increase in ‘ size continuously.

(ii) Environment and new needs: A change in the environment brings about changes in the need of the organisms. In response to the changing environment, the organisms develop certain adaptive characters. The adaptations may be in the form of development of new parts of the body.

(iii) Use and disuse theory: Lamarck’s use and disuse theory state that, if an organ is used constantly, the organ develops well and gets strengthened. When an organ is not used for a long time, it gradually degenerates. The ancestors of Giraffe were provided with a short neck and short forelimbs. Due to a shortage of grass, they are forced to feed on leaves from trees. The continuous stretching of their neck and forelimbs resulted in the development of long neck and long forelimbs, which is an example fcc constant use of an organ. The degenerated wing of Kiwi is an example for organ of disuse.

(iv) Theory of Inheritance of acquired characters: Animals respond to the changes when there is a change in the environment. The develop adaptive structures. The characters, developed during their lifetime, in response to the environmental changes are called acquired characters. The acquired characters are transmitted to the offspring by the process of inheritance.

VI. Higher-Order Thinking skills [HOTS] Questions

Question 1.

  1. What is the reason for the long neck of a giraffe.
  2. Name the theory based on the shown figure.

Answer:

  1. Due to a shortage of grass, they were forced to feed on leaves from trees. The continuous stretching of their neck and forelimb as resulted in the development of a long neck and long forelimbs.
  2. Theory of inheritance of acquired characters.

Question 2.
What are living fossils?
Answer:
Living fossils are living organisms that are similar in appearance to their fossilized distant ancestors and usually have no extinct close features, eg. Ginko Biloba.

Question 3.
What is Mars 2020 Astrobiology?
Answer:
NASA is developing the Mars 2020, Astrobiology to investigate an astrobiological relevant ancient environment on Mars, its surface geological processes and the possibility of past life on Mars and preservation of biosignatures within accessible geological materials.


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