Class 10 | Aster Classes

Time Allowed – 3 hours

Maximum Marks – 70

GENERAL INSTRUCTIONS

1. All questions are compulsory.

2. There are total 42 questions.

3. Question paper is divided into three sections-A, B and C.

4. Section A has question no.1to 14 (objective type questions) and are of 1 mark each.

5. Section B has question no. 15 to 28 (case study based multiple choice questions) and are of 1 mark each.

6. Section C has question no.29 to35 of 2 marks each, question no.36 and 37 of 3 marks each, question no.38 to40 of 4 marks each and question no.41 and 42 of 5 marks each.

7. Internal choices are given in some questions. 8.Support your answers with suitable examples wherever required.

SECTION A (OBJECTIVE TYPE QUESTIONS)

Multiple Choice Questions

1. Choose the correct answer:

Which of the following statement is incorrect

a. In warm climate light meals should be planned.

b. In cold climate energy giving food are preferred.

c. Non vegetarian dishes are the only source of protein in one’s diet.

d. Food group is a collection of foods which have similar nutrients.

OR

Which of the following statement is correct-

a. Expensive food is more nutritious.

b. Meals planned should be rigid.

c. Seasonal food is expensive.

d.Meals planned should be attractive and appealing.


2. Your friend does not like to include fruits and vegetables in her meals. She does not like to eat homemade meals. Convince your friend to include fruits and vegetables in his/her diet as it provides

a. Fibre

b. Fats

c. Protein

d. Omega fatty acids

OR

What is the main purpose of carbohydrates in our body?

a. They provide chemicals to repair cells.

b. They help to maintain body temperature.

c. They are the main source of energy for the body.

d. They help in building the muscles of the body


3. For preparing fruit pudding , you need tinned pineapples and cherries. What point/s you will consider while buying tinned fruits? The tin should not be

a. Bulging

b. Dented

c. Rusted

d. All of the above


4. Your younger brother is going to buy vegetables from the vendor for the first time. Advice him which of the following point he can ignore while buying vegetables-

a. Freshness of vegetables

b. Price of vegetables

c. Measurement of weighing table

d. Pointer in the weighing balance


5. Predict the changes which occurs in relation to physical development –

a. Height

b. Weight

c. Body proportion

d. All of the above

OR

Choose an emotional characteristic of a child who is in early childhood –

a. Unpredictable

b. Socially approved

c. Intense

d. Imaginary


6. When Rahul took out his shirt from cupboard hung on iron hanger ,it had a stain on it. Identify this stain –

a. Oil

b. Curry

c. Rust

d. Grease

OR

Raj stained his shirt with newly painted door. This stain can be classified as

a. Dye stain

b. Mineral stain

c. Animal stain

d. Vegetable stain


7. You always find your mother doing many activities before she leaves for her office like preparing breakfast and lunch, ironing clothes, cleaning home, laundering of clothes, etc. This is called as-

a. Dovetailing

b. Peak load period

c. Leisure time

d. Flexible activities


8. Nitish always prepare time plan for his day and he is good in studies as well as swimming. Which of the following is/are advantage of time management

a. It helps in saving time.

b. It helps in saving energy

c. It generates free time.

d. All of the above

OR

Radha always complains of lack of time to finish all her assignments. She fails to manage her time. Failing to manage time can lead to some consequences like

a. Less Stress

b. Greater productivity and efficiency

c. A better professional reputation

d. Missed deadlines


9. You have appointed a new cook at your home. Advice him at what temperature should cold and hot foods held to keep them safe? C° C and above 57°

a. Below 5 C° C and above 47°

b. Below 8 C° C and above 67°

c. Below 2 C° C and above 77°

d. Below 6


10. Mrs. Verma’ s three year old son has started going to nursery school. Advise her what kind of food should be given to him

a. Finger foods

b. Fried food

c. Sweet food

d. Strongly flavoured food

OR

Your grandfather has turned seventy years old. Advise what kind of food should be preferred by him

a. Spicy food

b. Fried food

c. Strong flavoured food

d. Light and digestible food


Chapter 10, Disaster Management, Science Part II, Solutions, for, Class 10, Science, Maharashtra board,

Question 1:Complete the table.(Motor accident, landsliding, forest fire, theft, riot, war, epidemic, drought, locust attack, financial crisis, flood, famine)

DisasterSymptomsEffectsRemedy

ANSWER:

DisasterSymptomsEffectsRe
medy
Motor acci
dent
Rash driving, drink and drive, ignorance to safety rulesLoss of life, loss of pro
perty
Following traffic rules, avoid driving if tipsy
Land slidingNew cracks or bulges in the ground, street or sidewalks, sunken road bedsLoss of property, loss of life, adverse impact on environmentGive help to clear debris, call an ambulance to send victims to hospitals
Forest fireLightning, human activities involving smoke and fire near forests areasImpact on environment, loss of lives of animalsCall fire brigade, give first aid to animals which survived the burns
TheftSheer carelessness towards property and wealthTension and loss of propertyInforming police, giving emotional support
RiotOpinion differences, political in
fluence
Loss of life and pro
perty
Give shelter to innocent victims, provide food and clothing and first-aid to the victims
WarTransgressing, opinion differences bet
ween countries 
Loss of life and pro
perty,  Impact on the country and its eco
nomy
Give shelter to inno
cent victims, provide food, clothing and first-aid to the victims
EpidemicSpreading of viruses from differ
ent animals
Loss of life, health risks, impact on environment Give proper medication to people, preparing anti
dotes against epide
mic
DroughtNo rainfall for long durationFood and water crisis, loss of lifeDonate food and water for victims, provide shelter and monetary help 
Locust attackLeaf distortion, chlorosis, yellow to brown spots, premature leaf dropCrop destruction, scarcity in foodSpraying pesticides
Financial crisisBankrupt, loss in business or services in individual caseImpact on the country and its economy, impact on individualGiving support to friends and family, asking support from other countries when crises happens in a country
FloodCloudburst, heavy rainfallHealth risks, loss of property,  food and water crisis, loss of lifeDonate food and clothing for flood victims, stay at some height if possible 
FamineHeavy rainfall, droughtFood and water crisis, displacement of people, loss of lifeDonate food and water for victims, provide shelter and monetary help 

Question 2:

Write notes.

a. Disaster management Authority

b. Nature of disaster management

c. Mock drill

d. Disaster Management Act, 2005

ANSWER:

a. Disaster Management Authority has the responsibility of making the policies, plans and guidelines for disaster management to ensure timely and effective response to disasters. This authority has been established at the level of government. Following flow chart indicates the function of control and coordination under the disaster management from national to village level. Disaster Management Act, 2005 has been passed in our country.

b. Disaster management is the strategy and course of action to be executed at the time of any such disaster to save as much life as possible. It can be divided into two parts:

Pre-disaster Management:Pre-disaster management phase is concerned with the complete preparation and planning in order to enable us to face any kind of situation.The first step includes identifying the pro-disaster areas.The second step includes collecting information about intensity of disaster and probable sites of disasters using predictive intensity maps and hazard maps.Next step is to get training for disaster management.Another important aspect of pre-disaster management is spreading awareness among the common people through various awareness programmes.

Post-disaster Management:Post-disaster management is concerned with the situation that arise after a disaster has occurred. It includes the following components:The primary concern is to provide help to victims preferably with the participation of local people.Establishment of help centres to provide all kind of possible help required by the people.Categorisation of help materials that are received from the help centres and distributing them efficiently to the people affected by the disaster.


c. Mock drills are a way of checking the preparedness of facing a disaster.

During mock drills, an apparent situation is created to check the reaction time and the type of response. 

Mock drills are carried out in schools, offices, public places, etc.

for situations like fire accidents, terrorist attack, etc.


d. The Disaster Management Act, 2005 was passed by Rajya Sabha on 28 November, and by the Lok Sabha on 12 December 2005.

It received approval from the President of India on 9 January 2006.

This act has 11 chapters and 79 sections. The act extends to the whole of India.

This act called for the formation of National Disaster Management Authority (NDMA) with prime minister of India as its chairperson.

The Act under Section 8 encouraged the central government to constitute a National Executive Committee (NEC) to assist the National Authority.

All State Governments are mandated under Section 14 of the act to establish a State Disaster Management Authority (SDMA).

Section 42 of the act calls for establishing a National Institute of Disaster Management.


Question 3:

Answer the following questions.

a. Explain the role of district disaster control unit after occurrence of any disaster.

b. Give the reasons for increase in human disasters after the World War-II.

c. Which are the objectives of disaster management?

d. Why is it essential to get the training of first aid?

e. Which different methods are used for transportation of patients? Why?

ANSWER:

a. District control unit is formed either after the impact of disaster or getting intimation about it. It analyse about various aspects of disaster, keeps continuous contact with various agencies like army, air force, navy, telecommunication department, paramilitary forces, etc. for getting help. It is also responsible for coordinating with various voluntary organizations for their help in disaster management.


b. After World War-II, there has been a vast advancement in technology.

This has led to tremendous increase in human disasters.

For example, the advancement in nuclear energy field has led to setting up of various nuclear power plants.

The radiations via these power plants are affecting the environment as well as living beings.

Also, the set up of various oil factories near the seas are affecting aquatic life.

After the World War-II, the number in motor vehicles have increased exponentially.

Due to this, motor accidents have become very frequent these days.

Other reasons of increasing human disasters are oil spills, nuclear meltdown, terrorism, biological warfare, etc. 


c. The objectives of disaster management are as follows:

Improving tolerancePreventing losses and dangersProviding relief to the affected people Preparing for actions to be taken at the time of disasterAssessing the damage caused Arrangement of rescue for the affected Rehabilitation and rebuilding the affected aread.


d. It is essential to get the training of first aid because of the following reasons:

It enables the person to use appropriate precautionary methods to save lives during emergency.

It enables the person to give primary help and medications to victims before actual medication.

It enables the person to prevent further damage to victims.

It enables the person to be relaxed and calm during critical situations.

It enables the person to give comfort and care to the victim.


e. In emergency condition, different methods are used for transportation of patients.

The methods to be adopted depends on the condition of the patient.

Following are the various condition to be adopted while transporting patients:

Cradle method: useful for children and under-weight victims.

Carrying piggy back: useful for carrying patients who are unconscious.

Carrying on two hands chair: useful for those patients who cannot use their hands but can hold their body upright. 

Pulling or lifting method: useful for carrying an unconscious patient through a short distance.

Carrying on four-hand chair: useful when support is needed for the part below the waist.


Question 4:

On the basis of the structure of disaster management authority, form the same for your school.

ANSWER:

It is an activity based question. Kindly do it yourself.


Question 5:

Write down the reasons, effects and remedial measures taken for any two disasters experienced by you.

ANSWER:

Note: The disaster experienced can vary from person to person.


Two disasters experienced are:

(i) Motor accident:

Reason: rash driving and ignorance to safety rules

Effects: Injuries to oneself and family as well as damage to property.

Remedial measures: Giving emotional support to victims, calling ambulance and taking the victims to hospital

(ii) Theft:

Reason: sheer carelessness towards property and wealth.

Effects: loss of life and property.

Remedial measures: Giving emotional support to victims, calling police to register the case


Question 6:

Which different aspects of disaster management would you check for your school? Why?

ANSWER:

Following are the main aspects of disaster management:

Preparation: A plan is created to minimise the damage if a disaster occurs.

Redemption: It is the plan to minimise the damage to the society and country.

Preparedness: A plan is chalked out to get quick response from public and administration.

Impact of disaster: Intensity of disaster and disaster management are reviewed.

Response: This stage deals with providing immediate response after an incident has occurred.

Resurgence: It is an important link between emergency measures and national progress. It includes the steps which are required for the welfare and rehabilitation of the nation. 

Restoration: It is an important link between measures after disaster and national development. It includes steps useful for progress ofnation and rehabilitation.Do a survey of your school and find out which aspects of disaster management are needed to be checked for your school.


Question 7:

Identify the type of disaster.a. Terrorismb. Soil erosionc. Hepatitisd. Forest firee. Faminef. Theft

ANSWER:

a. Terrorism: Man-made

b. Soil erosion: Man-made as well as natural

c. Hepatitis: Natural

d. Forest fire: Man-made as well as natural

e. Famine: Natural as well as man-made

f. Theft: Man-made


Question 8:

Some symbols are given below. Explain those symbols. Which disasters may occur if those symbols are ignored?

ANSWER:

These symbols come under globally harmonised system (GHS) adopted by UN for labelling and classification of chemicals.


(i) This symbol is used for hazardous products which causes less severe health effects. This symbol indicates that the product has acute toxicity, can cause skin and eye irritation, can be hazardous to ozone layer, can affect respiratory organs as well as has narcotic effects. If this symbol is ignored, then health issues as mentioned above can arise as well as can impact the environment.


(ii) These are used for products which have deathly effects on exposure to small amount of it. This symbol indicates that the product has acute oral, dermal and inhalation toxicity. It would prove fatal if the product with this symbol is swallowed or inhaled.


(iii) This symbol is used to represent that the product is hazardous to aquatic life. If these products are spilled in oceans or seas, then it can have fatal and long lasting effects on aquatic organisms.


(iv) This symbol indicates that the product can cause serious health effects. The product with this symbol can cause respiratory sensitivity, skin toxicity, germ cell mutagenicity, carcinogenicity, reproductive toxicity, aspiration hazard, specific target organ toxicity after single exposure or repeated exposure.


(v) This symbol is used to indicate that the product is capable of corroding metals and cause irritation to eyes and skin. The product with this symbol can also cause severe burns to skin as well as damage the eye.


(vi) This symbol represents that the product is good oxidising liquids or solids. The product having this symbol can cause fire or explosions or can even intensify fire.


(vii) This symbol represents flammable gases, aerosols, liquids and solids; pyrophoric liquids, gases and solids, self-reactive substance or mixtures, organic peroxides. The product having this symbol can cause fire on heating.


(viii)  This symbol represents that the product is an unstable explosive or it is a self-reactive substance or mixtures. This symbol is also placed on labels of organic peroxides. The product having this symbol can cause explosions on heating.


(ix) This symbol is used to represent the hazard of gases under pressure such as dissolved gas, liquefied gas, compresses gas or refrigerated liquefied gas. The product having this symbol may explode on heating as well as may cause cryogenic burns and injuries.


Question 9:

Explain why it is said like that?A] Mock drill is usefulB] Effective disaster management makes us well prepared for the future.

ANSWER:

A. It is very correct to say that mock drills are very important and useful.

These drills should be conducted at every workplace, schools, public places etc.

These drills ensure a way of checking the preparedness of facing a disaster.

Through mock drills, we can evaluate the response or reaction time to a disasterwe can identify our own abilitiescoordination between various departments of disaster control can be improvedwe can check the competency of the planned actionswe can identify the possible errors and risks

B. We know that disasters are sudden and unplanned and thus can’t be avoided in most cases.

But if effective disaster management is employed and exercised, then we would certainly achieve the abilities to face the adverse effects of disasters.

Hence, through effective disaster management, we actually make ourselves prepared for future.

Through effective disaster management, we can supply essential commodities to the people after or before disasterwe can arrange rescue for the affectedwe can rehabilitate and rebuild the affected area in short span of timewe can minimise losses of life and propertywe can build tools to assess the damaged cause.


Question 10:

Complete the following chart

ANSWER:


Question 11:

Following are the pictures of some disasters. How will be your pre- and post-disaster management in case you face any of those disasters?

ANSWER:

(a) Pre-disaster management: Avoid drinking cold water and eating ice-creams.

Post-disaster management:Visit a doctorTake proper medication and restAvoid going to public places.

(b)  Pre-disaster management: Discussing the problem with eldersTrying to settle the dispute verbally.

Post-disaster management:Identifying any serious injuries occurred to oneself or the counterpart. Getting proper medication for the sameApologizing to each other.

(c)  Pre-disaster management: Keep an emergency kit. This kit should consist of portable lights, medicines etc.Keep extra dry food and portable waterMove to higher floors if possibleSwitch off all the electrical appliances. 

Post-disaster management:Avoid going to water flooded areas as there are chances of harmful insects being present there Check for the casualties aroundHelp the victims in need.

(d) Pre-disaster management: Keep an emergency kit. This kit should consist of portable lights, medicines etc.Keep extra dry food and portable waterMove to locations which are less prone to cyclonesSwitch off all the electrical appliances. 

Post-disaster management:Clearing the debris left behind the cycloneHelp the victims in need check for the ruptures or cracks on the wall of house.


Chapter 9, Social Health, Science Part II, Solutions, for, Class 10, Science, Maharashtra board,

Question 1:

Fill in the blanks with an appropriate word.

a. Laughter club is a remedy to drive away — — — –.

b. Alcohol consumption mainly affects — — — — system.

c. The act — — — — is to curb cyber crimes.

ANSWER:

a. Laughter club is a remedy to drive away mental stress.

b. Alcohol consumption mainly affects the nervous system.

c. The act 2000 is to curb cyber crimes.


Question 2:

Answer the following.

a. Which factors affect the social health?

b. Which changes occur in persons continuously using internet and mobile phones?

c. Which problems do the common man faces due to incidences of cyber crime?

d. Explain the importance of good communication with others.

ANSWER:

a. The factors which affect social health are:


Mental stress: The response of our body to a demand or threat is known as stress and it can be both physical and mental. Mental stress is a major contributor to poor social health. Increase in competition in several aspects of life has resulted in increased mental stress. Stressors like best education, better employment, hectic work schedules, nuclear families, loneliness, etc. have added to this menace. 

Addiction: Addiction is a mental condition in which an individual’s brain is manifested by compulsive use of harmful substances despite being aware of the fact that those substances are harmful.Things such as alcohol, drugs and tobacco are addictive substances, frequent use of which results to their addiction. The effect of these substances are long lasting on mental, physical and social health. Continuous use of such substances adversely affects the nervous system, thus impairing the thinking and decision making ability of the individual. It also leads to poor social health which affects the interpersonal relationships and the social status of an individual.

Incurable diseases: Diseases like AIDS, tuberculosis etc. are considered incurable diseases and are considered a deterrent to social health. Apart from being deadly and at times being incurable, there are various kinds of social stigmas associated with these diseases. People who suffer from such diseases are often excluded from society and forced to live a life of seclusion.


b. There are various physical and mental changes which occur in a person who continuously uses internet and mobile phones. Some of the physical and mental changes are:


Physical changes:tiredness and headacheinsomniaforgetfulnesstinnitus and joint painproblems in vision weight gain.


Mental and emotional changes:
the person becomes irritantlack of patiencedevelopment of aggressionthe person becomes introvert and self centered.


c. Cyber crime is a crime which uses the computer for carrying out illegal actions, such as hacking data, misuse/illegal sale of literature, etc. There are various effects which cyber crime has on the mental social health of an individual. It can lead to monetary loss, leak of data and personal information of individuals and organisations etc. Such kind of actions leaves a person traumatisedand disturbs the mental peace of an individual. This mental disturbance is reciprocated in the form physical and social effects which directly or indirectly affect the interpersonal relationship of individuals.



d. Communication is a vital skill which plays an important role from personal to professional life. Good communication skills does not only mean good verbal skills but it also implies to one’s listening skills. Communication with others helps to overcome your problems, provide you with moral support and also you get to understand the perspective of people on different issues. Good communication skills help people to gain confidence and overcome stress situations. Apart from being a good orator, it is important that you are a good listener too. One should listen patiently to people around them and help them in best possible way. Good communication skills help you to make friends with long lasting relationship. It also teaches you how to put forward your points without hurting the sentiments of others. In other words we can say that, good communication skill result in the all round development of an individual.


Question 3:

Solve the following crossword

1. Continuous consumption of alcoholic and tobacco-materials.

2. This app may cause the cyber crimes.

3. A remedy to resolve stress.

4. Requirement for stress free life.

5. Various factors affect — — — health.

6. Art of preparing food items.

SOLUTION


Question 4:

Which are various ways to minimize stress?

ANSWER:

Stress can be defined as the response of our body to a demand or threat and it can be both physical and mental.

There are many ways of handling stress, out of which some are mentioned below:


1. Positive thinking

2. Indulging in favourite hobbies, such as singing, dancing, gardening, etc

3. Going for walks and practicing meditation

4. Playing favourite outdoor games

5. Talking to close family members and friends.


Question 5:

Give three examples of each.

a. Hobbies to reduce stress.

b. Diseases endangering the social health.

c. Physical problems arising due to excessive use of mobile phones.

d. Activities under the jurisdiction of cyber crime laws.

ANSWER:

a. Hobbies to reduce stress- Singing, playing sports and reading books

b. Diseases endangering the social health- AIDS, leprosy and mental disorders.

c. Physical problems arising due to excessive use of mobile phones- tiredness, headache and joint pain.

d. Activities under the jurisdiction of cyber crime laws- hacking of information, sale or misuse of written literature and spreading vulgar pictures.


Question 6:

What will you do? Why?

a. You are spending more time in internet/mobile games, phone, etc.

b. Child of your neighbor is addicted to tobacco chewing.

c. Your sister has become uncommunicative. She prefers to remain alone.

d. You have to use free space around your home for good purpose.

e. Your friend has developed the hobby of snapping selfies.

f. Your brother studying in XII has developed the stress.

ANSWER:

a. If, I am spending more time on phones and video games, then the first thing is that I should realise that I am spending a lot of time on these things.

I would try to limit my usage of mobiles, video games etc.

by diverting myself into other activities.

These other activities could be anything like playing outdoor games, cooking or just meeting my friends.

I would make a conscious effort to take out more time for social gatherings and make new friends in personal rather than on facebook or other sites. 


b. If I find out that my neighbour’s child is addicted to tobacco chewing, my first step would be to inform his parents.

I would sit with the child and try to explain him the harmful effects of tobacco chewing.

I will show him/her certain videos and pictures which highlight the damage caused by tobacco chewing.

If required, we can take the child for professional advice.


c. There must be a reason for my sister to become uncommunicative and my first step would be to figure out that reason.

Once, I get to know the reason, I will help her in finding the solution to the problem.

If required, I would look for professional help for her in the form of a psychologist.

I would try to indulge her in more of social activities and things that she likes to do.

I would advise her to talk to her friends and people who are close to her.

Being uncommunicative and preferring loneliness is not a good sign, it is important to deal with it at the earliest. 


d. If I have free space around my house, I would use that space for various purposes like-kitchen gardening playing outdoor game staking classes for under privileged students making a creative corner planting ornamental and medicinal plants.


​e. Snapping selfies is a kind of addiction and this addiction is not good for physical, mental or social health. If my friend is addicted to taking selfies, I would prefer talking to him and highlight the dangers of taking selfies. I would bring into his notice the various incidents which have occured due this selfie addiction.


f. There are various reasons because of which my brother may have developed stress.

Most possible reason is, that he is in class XII and is worried about his board exams and his future.

However, my first step would be to sit down with him and understand the cause of his stress.

After understanding the cause, I would work with him to chalk out a strategy to solve his problem.

I would talk to him in a manner that promotes him to think positively and his mind gets diverted from negative thoughts.

Another strategy would be to suggest him to indulge in his favourite activities.


Question 7:

What type of changes occurs in a home having chronically ill old person? How will you help to maintain good atmosphere?

ANSWER:

Having chronically ill old patients in a family affects the physical and mental state of others members of the family as well.

It is not easy to handle old age people and if they are ill, it becomes all the more difficult.

It not only affects the family monetarily but also drains them physically and emotionally as it is not easy to see the suffering of your loved ones.

Since, it is a tough situation, it is important that each and every person of the family keeps patience and stays calm.

They need to remain positive and ward off negative feelings and thoughts.

They should try to talk to the patient and share their entire day with them, even if they are not in a state of response.

Just being present around them, protects them from the feeling of loneliness.


Chapter 8, Cell Biology And Biotechnology, Science Part II, Solutions, for, Class 10, Science, Maharashtra board,

Question 1:

Fill in the blanks and complete the statements.
a. Methods like artificial insemination and embryo transplant are mainly used for — — —
b. — — — — is the revolutionary event in biotechnology after cloning.
c. The disease related with the synthesis of insulin is — — —.
d. Government of India has encouraged the — — — — for improving the productivity by launching NKM-16.

ANSWER:

a. Methods like artificial insemination and embryo transplant are mainly used for improving the quality and quantity of animal products.
b. Stem cell technology is the revolutionary event in biotechnology after cloning.
c. The disease related with the synthesis of insulin is diabetes.
d. Government of India has encouraged the people for pisciculture for improving the productivity by launching NKM-16.

Question 2:

Match the pairs.

a.Interferon1.Diabetes
b.Factor2.Dwarfness
c.Somatostatin3.Viral infection
d.Interleukin4.Cancer
5.Hemophilia
ANSWER:
a.Interferon. 3.Viral infection
b.Factor. 5.Hemophilia
c.Somatostatin. 2.Dwarfness
d.Interleukin. 4.Cancer

Question 3:

Rewrite the following wrong statements after corrections.
a. Changes in genes of the cells are brought about in non-genetic technique.
b. Gene from Bacillus thuringiensis is introduced into soyabean.

ANSWER:

a. Changes in genes of the cells are brought about in genetic technique.
b. Gene from Bacillus thuringiensis is introduced into cotton plants.

Question 4:

Write short notes.

a. Biotechnology: Professional uses.
b. Importance of medicinal plants.

ANSWER:

a. Biotechnology is the branch of biology that involves the application of technology in utilising the living organisms or their parts to produce products useful for humans. There are various applications of biotechnology, some of which are mentioned below:
(i) It is used in agriculture to produce improved varieties of plants and animal breeds, and to control pests and pathogens.
(ii) It is applied in food processing industries to produce additives.
(iii) It is applied to produce biocatalysts and biopolymers.
(iv) Many biotechnological processes are applied to control pollution and treat waste water.
(v) It is applied in the field of health care to produce several vaccines, drugs and hormones like insulin, etc.

b. Several plants have medicinal properties which can be used as medicines.
Some of the plants grown for their medicinal value are: Cinchona − Quinine, a drug used in the treatment of malaria, is obtained from the bark of the Cinchona tree.
Rauwolfia (Sarpagandha) − This plant is used for the treatment of hypertension and insomnia.
Belladonna − Alkaloids obtained from the roots of this plant are used as pain relievers.
It also stimulates respiration and circulation.
Eucalyptus − The leaves of eucalyptus are used for extracting on oil which is used in the treatment of blocked nose and throat infections.
It is also used as a mosquito repellent.

Question 5:

Answer the following questions in your own words.

a. Which products produced through biotechnology do you use in your daily life?
b. Which precautions will you take during spraying of pesticides?
c. Why some of the organs in human body are most valuable?
d. Explain the importance of fruit processing in human life?
e. Explain the meaning of vaccination.

ANSWER:

a. There are various products which we use in our daily life that are produced by biotechnological processes.
These products belong to the category of: Medical products like antibiotics, vaccines and insulin.
Fruits and dairy products. Microbial metabolites like vitamins and enzymes.
Organic acids like acetic acid/vinegar.

b. Pesticides are chemicals which are used on plants for protecting them against pest infection.
They contain various kinds of chemicals which are harmful to humans as well as the environment.
There are certain points which should be taken care of while using pesticides like, cover the nose, mouth and eyes while spraying them, keeping them out of the reach of children.
Another important point is to prevent excessive use of pesticides as they also lead to water and soil pollution.
Instead one should adopt natural or biological methods to ward off pests.

c. We know that the human body is a system which is comprised of various types of organs.
These organs have specific and important roles to play and in the absence of their functioning, normal body functions cannot be carried out.
There are various reasons like aging, accidents, infections, disorders because of which an organ may become non functional.
Such situation can eventually result in the death of the patient.
However, organ transplant is a solution for such cases.
There are organs that can be donated to such people and our thus valuable, for example, heart, kidneys, eyes, liver etc.

d. Fruits are something which we eat everyday.
Fruits are called perishable products which means that they cannot be stored for long durations.
The solution to this problem is fruit processing.
Fruit processing is a process which converts fruits into jams, juices, jellies etc.
These processing methods include storage in cold areas, drying salting etc.
This process makes the fruits available all year and makes their storage possible.

e. Vaccines are dead or weakened microorganisms, which help the body in fighting against diseases.
Our body reacts to infection by microorganisms by producing certain substances called antibodies.
These antibodies kill the invading microorganisms, thereby freeing the body from diseases.
In order to protect the body from diseases caused by microorganisms, some dead or weakened microbes are introduced in the body, which cause the production of antibodies.
These antibodies then remain in the body for a long period of time protecting the body from diseases.
This whole process of introducing vaccines into the body is known as vaccination.

Question 6:

Complete the following chart.

ANSWER:


Question 7:

Write the correct answer in blank circles.

ANSWER:


Question 8:

Identify and complete the following correlations.

a. Insulin : Diabetes :: Interleukin : — — —
b. Interferon : — :: Erythropoietin : Anemia.
c. ——- : Dwarfness :: Factor VIII : Hemophilia.
d. White revolution : Dairy :: Blue revolution : — — — –.

ANSWER:

a. Insulin: Diabetes :: Interleukin: Cancer 
b. Interferon: Viral infection  :: Erythropoietin: Anemia
c. Somatostatin : Dwarfness :: Factor VIII: Hemophilia
d. White revolution: Dairy :: Blue revolution: Aquatic organisms 

Question 9:

Write a comparative note on usefulness and harmfulness of biotechnology.

ANSWER:  

Biotechnology has revolutionised the field of science and technology.
It has provided us with solutions to our problems which would not have been possible otherwise.
It has found widespread applications in various fields and its many potentials are still being exploited.
However, despite the various merits of biotechnology, there are certain disadvantages also associated with it.

Merits of biotechnology:

it has helped in the field of agriculture for the development of stress resistant varieties for example drought resistant, temperature resistant plants etc.
it has been useful in the medical field in the diagnosis and treatment of various kind of diseases.
it is being widely applied in the food industry for producing different kinds of food products on a larger scale.
it’s potential for solving environmental problems is also being exploited.
For example, microorganisms are being used to solve the menace of plastics.


Demerits of biotechnology


Although biotechnology has found widespread applications in various fields, it has its own potential risks.
Some of its demerits are:
some of the biotechnological procedures are against nature and natural laws as they involve other living organisms and disturbing their genetic makeup.
new and advanced varieties of crops produced by biotechnology, which are considered to be healthier and better, also have some disadvantages like seed sterility.
it may also lead to the development of antibiotic resistant bacteria there are various ethical issues associated with products produced by biotechnological processes.

Chapter 7, Introduction To Microbiology, Science Part II, Solutions, for, Class 10, Science, Maharashtra board,

Question 1:

Rewrite the following statements using correct of the options and explain the completed statements.
(gluconic acid, coagulation, amino acid, acetic acid, Clostridium, Lactobacilli)
a. Process of — — — — of milk proteins occurs due to lactic acid.
b. Harmful bacteria in like — — — in the intestine are destroyed due to probiotics.
c. Chemically, vinegar is — — –.
d. Salts which can be used as supplement of calcium and iron are obtained from ——– acid.

ANSWER:

a.  Process of coagulation of milk proteins occurs due to lactic acid.
b. Harmful bacteria in like Clostridium in the intestine are destroyed due to probiotics.
c. Chemically, vinegar is acetic acid.
d. Salts which can be used as supplement of calcium and iron are obtained from gluconic acid.

Question 2:

Match the pairs

A GroupB Group
a. Xylitol
b. Citric acid
c. Lycopene
d. Nycin

1. Pigment
2. To impart sweetness
3. Microbial restrictor
4. Protein binding emulsifier
5. To impart acidity

ANSWER:

Group AGroup B
a. XylitolPigment
b. Citric acidTo impart sweetness
c. LycopeneMicrobial restrictor
d. NycinProtein binding emulsifier


Question 3:

Answer the following.

a. Which fuels can be obtained by microbial processes? Why is it necessary to increase the use of such fuels?
b. How can the oil spills of rivers and oceans be cleaned?
c. How can the soil polluted by acid rain be made fertile again?
d. Explain the importance of biopesticides in organic farming.
e. Which are the reasons for increasing the popularity of probiotic products?
f. How the bread and other products produced using baker’s yeast are nutritious?
g. Which precautions are necessary for proper decomposition of domestic waste?
h. Why is it necessary to ban the use of plastic bags?

ANSWER:

a. There are different kinds of fuel which can be produced with the help of microbes.
Some of the examples of such fuels are:
1. Ethanol– It is a byproduct which is produced during fermentation of molasses by Saccharomyces. It is a type of alcohol and is a clean (smokeless) fuel. It is mixed with petrol and diesel to prevent vehicular emission.
2. Methane– Methane is a gaseous fuel which is obtained by microbial anaerobic decomposition of urban agricultural and industrial waste.
3. Hydrogen fuel: Hydrogen is released during bio-photolysis of water in which bacteria perform photoreduction. It is considered as the fuel of the future as it is non polluting and an efficient fuel.
Fuels which are obtained from fossil fuels are non renewable and also polluting. These fuels like hydrogen, ethanol, methane are the future fuels as they burn cleaner with  same efficiency and are renewable. Thus, their use needs to be promoted further.


b. Oil spills are a form of pollution in which liquid fuels, like petroleum are spilled on water, land or air. Oil spills usually occur in oceans where there is accidental leakage of oil. It is harmful to the aquatic life as it reduces the availability of oxygen and would eventually result in their death. It is difficult to clear out oil spills as the methods used are not much efficient and take a lot of time. To solve this issue, a new approach has been developed which uses bacteria known as hydrocarbonoclastic bacteria (HCB) for this purpose. These group of bacteria are capable of degrading pyrimidines and other chemicals. They convert hydrocarbons to CO2 and oxygen. Pseudomonas sp. and Alcanivorax borkumensis are used for this purpose.


c.  The sulphuric acid which is a part of acid rain and is released from various industries is a common pollutant of soil.
Soil which has been polluted by sulphuric acid cannot be used for cultivation of plants.
However, there is a way of treating this soil to make it fertile again.
Microorganisms like Acidiphilium sp. and Acidobacillus ferrooxidans can be used in the treatment of soil polluted with sulphuric acid.


d. Biopesticide is a term used for bacterial and fungal toxins which can be used to destroy pests/pathogens/insects and can be directly integrated into the plants. The special characteristics of biopesticide is that they do not harm the plant or other organisms except its target organism.
Some of the examples of biopesticides are-

 Bacillus thuringiensis (Bt) is used to control butterfly caterpillars.
This bacterium is available in sachets as dried spores, which are sprayed on the crops.
The spores get into the gut of the larvae and kill it while the other insects remain unperturbed.
By methods of genetic engineering, the genes of B. thuringiensis responsible for killing the larvae have been incorporated into the plants.
Cotton plant with Bt gene incorporated is called Bt-cotton.
The fungus Trichoderma living in roots of plants acts as a biocontrol agent against several plant pathogens.
Baculoviruses, particularly genus Nucleopolyhedrovirus are also used as narrow spectrum insecticidal agents.


 e. Probiotics are such edible preparations which contain useful active bacteria, like Lactobacillus, Acidophilus, Lactobacillus casei, Bifidobacterium bifidum, etc.
There are various reasons for which probiotics are being promoted nowadays.
These bacteria are beneficial for the intestine as they help in the process of metabolism.
They are usually given when a person is suffering from diarrhoea or is under antibiotic treatment.
Antibiotics kill both beneficial and harmful bacteria present in our body, thus affecting the metabolic process.
These probiotics form the colonies of useful microbes in alimentary canal and thus aid in the digestion process.

f. Baker’s yeast is commonly used in food production.
It’s major application is in the food industry where it is used in various baking procedures as well as for fermentation purposes.
Fermentation of fruit juices, maple syrup, sugar molasses etc.
with the help of yeast yields ethanol whereas it is used in baking breads and other products as it provides them with a fluffy and spongy characteristic.
Apart from this, yeast is also a rich source of carbohydrates, fats, proteins, various vitamins, and minerals which means it also increases the nutritive value of the product to which it is added.

g. Domestic waste refers to the waste which is generated in our houses due to our daily activities. Domestic waste can be either biodegradable or non biodegradable for example, vegetable and fruit peels are biodegradable whereas batteries, computers etc are non biodegradable. biodegradable products can be used for making composts which can be used in parks, plant pots etc. For non biodegradable products we need to practice the 3R’s and only after that they should be discarded as waste. The 3R’s are –
Reduce- Reduce the amount of waste produced.Reuse- Reusing a resource in a new way before throwing it.Recycle- Making something new from a material rather than throwing it away.


h. Plastic bags are non biodegradable products which pose a serious threat to the environment. Non biodegradable products do not decompose easily and thus keep on accumulating in the environment. There are various other reasons for which plastic bags should be banned, for example: plastic bags, on getting into drains and sewer system, choke them up resulting in spilling of dirty water on the roads burning of plastic bags produces harmful gases, which can cause health problems street animals may consume these plastic bags, which may even result in their deaths.

Question 4:

Complete the following conceptual picture.

ANSWER:



Question 5:

Give scientific reasons.

a. Use of mutant strains has been increased in industrial microbiology.
b. Enzymes obtained by microbial process are mixed with detergents.
c. Microbial enzymes are used instead of chemical catalysts in chemical industry.

ANSWER:

a. Mutant varieties of microorganisms are different from the original microorganism. Mutant varieties are created by insertion of genes of interest in a particular organism through a technique called genetic engineering. Mutant microorganisms have characteristics which are not present in the original strain and thus make them useful for various purposes.


b. Enzymes obtained by microbial process are mixed with detergents because it makes the cleaning process efficient. Addition of enzymes to detergents makes them efficient in removing dirt with an added advantage of being able to work at lower temperatures.


c. Microbial catalysts are also known as biocatalysts. Microbial catalysts are preferred over chemical catalysts for various reasons like:  Lesser byproducts are formed in case of microbial enzymes which means the cost of purification is minimised. Microbial enzymes can function at low temperatures, pH and pressure, thus saving the energy. Enzymes which are used in these processes can be reused as they do not decompose during these processes. Use of enzymes also reduces the amount of environmental pollution.

Question 6:

Complete the following conceptual picture with respect to its uses.

ANSWER:


Question 7:

Complete the following conceptual picture related to environmental management.

ANSWER:


Question 8:

Answer the following.

a. What is the role of microbes in compost production?
b. What are the benefits of mixing ethanol with petrol and diesel?
c. Which plants are cultivated to obtain the fuel?
d. Which fuels are obtained from biomass?
e. How does the bread become spongy?

ANSWER:

 a. Microbes play an important role in various aspects of our lives.
One such important role is the formation of compost.
The biodegradable waste which is collected from all around the cities are placed in landfill sites.
Landfill sites are created by digging deep pits away from residential areas and biodegradable waste is dumped into it.
The conversion of this waste is then carried out by various kinds of microorganisms, specially aerobic bacteria and some kind of fungi.
It takes time for formation of compost and then the landfill site is again ready to use while the compost can be used in agricultural fields, parks etc.


b. Nowadays, many countries are practicing mixing of ethanol with petrol and diesel.
Ethanol is a clean burning fuel and reduces the vehicle exhaust emissions. Also.
it is an easily available and cheap source which makes it suitable for this purpose.


c. Biofuels can be obtained from cultivating plants like corn, sugarcane, palm oil, jatropha, soybean, switchgrass and rapeseed.


d. Fuels which are obtained from biomass are called bio fuels and they are an important and renewable source of energy.
Biofuels can be in the form of either solid, liquid or gases.
Solid biofuels- coal, dung, crop residueLiquid- vegetable oils, alcoholGaseous- gobar gas, coal gas


e. Breads become spongy due to the addition of yeast in their dough.
Yeast reproduces rapidly and produces carbon dioxide gas while respiring.
This gas fills the dough and increases its volume making it to rise, thus making the bread appear spongy and fluffy.


Chapter 6, Animal Classification, Science Part II, Solutions, for, Class 10, Science, Maharashtra board,

Question 1:

Identify me.

a. I am diploblastic & acoelomate. Which phylum do I belong to?
b. My body is radially symmetrical. Water vascular system is present in my body. I am referred to as fish though I am not. What is my name?
c. I live in your small intestine. Pseudocoelom is present in my thread like body. In which phylum will you include me?
d. Though I am multicellular, there are no tissues in my body. What is the name of my phylum?

ANSWER:

a. I belong to the phylum Cnidaria.
b. I belong to the phylum Echinodermata and my name is Star fish/Asterias.
c. You belong to the phylum Aschelminthes and your name is Ascaris.
d. The name of phylum is Porifera.

Question 2:

Write the characters of each of the following animals with the help of classification chart.
Bath sponge, grasshopper, rohu, penguin, frog, lizard, elephant, jellyfish.

ANSWER


Question 3:

Write in brief about progressive changes in animal classification.

ANSWER:

 There are various scientists which have contributed to biological classification and based on their observations we have the current system of classification:
Aristotle (384-322 BC): Also known as the father of classification, he classified animals on the basis of two points: presence or absence of blood, whether they live on land, air or water.
Carolus Linneaus (1707-1778): Also known as the father of taxonomy, he classified living things into two kingdoms- Plantae and Animalia.
Ernst Haeckel (1834-1919): He proposed the three kingdom classification- Plantae, Animalia and Protista.
Robert Whitakker (1920-1980): He gave the five kingdom classification- Monera, Protista, Fungi, Plantae and Animalia.
Carl Woose (1928-2012): He gave the classification where he classified all the organisms into three categories- Eukarya domain, Bacteria domain and Archaea domain.

Question 4:

What is the exact difference between grades of organization and symmetry? Explain with examples.

ANSWER:

Grades of organization:
We know that all organisms are made up of cells out of which some organisms may be unicellular while some may be multicellular. Grade of organisation refers to the levels in which the cells are arranged.

There are different grades of organisation like:

Cellular level of organization: It is a loose aggregation of cells in which the cells are functionally different from one another.
Tissue level of organization: In this, different cells performing similar functions are arranged into tissues.
Organ level of organization: Here, different tissues are organized into organs and each organ is specialized for a particular function.
Members of the kingdom Animalia are multicellular and all of them exhibit the different pattern of organisation of cells.

The different levels of organization are as follows:

Cellular level of organization (Example: Porifera)
Tissue level of organization (Example: Coelenterata)
Organ level of organization (Example: Platyhelminthes)
Organ system level of organization (Examples: Nematoda, Annelida, Arthropoda, Mollusca, Echinodermata and chordates)
Symmetry is a characteristic through which animals may be distinguished from each other.
Animals that can be divided into two identical halves in one plane exhibit bilateral symmetry.
Animals that can be divided into many identical parts exhibit radial symmetry.
Animals that cannot be divided into identical parts are asymmetric.
If the body of an animal can be divided into two equal parts by any plane, it is said to be symmetrical.
(i) Animals showing radial symmetry − Hydra and sea anemone.
(ii) Animals showing bilateral symmetry − Human beings and prawn.

Question 5:

Answer in brief.

a. Give scientific classification of shark upto class.
b. Write four distinguishing characters of phylum- Echinodermata.

c. Distinguish between butterfly and bat with the help of four distinguishing properties.

d. To which phylum does Cockroach belong? Justify your answer with scientific reasons.

ANSWER:

a. The classification of shark is as follows: 
Kingdom– Animalia 
Phylum–  Chordata 
Sub- phylum– Vertebrata 
Class– Chondrichthyes


b.  Characteristic features of Echinodermata are:
they are called echinoderms because calcareous spines are present on the body of these animals.
their skeleton is made up of calcareous spines/ossicles (plates).
they show radial symmetry in adult stage whereas they show bilateral symmetry in larval stage.
these animals have the ability of regeneration.
they are found only in oceans.

c. 
Butterfly Bat
1. It belongs to the phylum Arthropoda.It belongs to the phylum Chordata and class mammalia.
Their characteristic feature is the presence of joint appendages.Their characteristic feature is the presence of mammary glands.
It shows the presence of chitinous exoskeleton.Exoskeleton is in the form of hair or fur.
They are cold blooded organisms.They are warm blooded organisms.

d. Cockroach belongs to the phylum Arthropoda.
It shows all the features which are characteristic of this phylum:
it shows the presence of jointed appendages it is triploblastic, coelomate, bilaterally symmetrical and segmented it has chitinous exoskeleton around its body it respires with the help of tracheal system.

Question 6:

Give scientific reasons.

a. Though tortoise lives on land as well as in water, it cannot be included in class- Amphibia.

b. Our body irritates if it comes in contact with jellyfish.

c. All vertebrates are chordates but all chordates are not vertebrates.

d. Balanoglossus is connecting link between non-chordates & chordates.

e. Body temperature of reptiles in not constant.

ANSWER:

a. Tortoise belongs to the class reptilia and does not show any characteristic which is similar to the class amphibia except that it can live in both land and water.
There are certain characteristics which are common to the amphibians which are not applicable for reptiles.
For example: amphibians have moist skin, neck is absent, external ear is in the form of tympanum whereas reptiles have dry and scaly skin, neck is present and external ear is absent.
So, we can say that tortoise is a reptile and not an amphibian based on the above characteristics.


b. Jelly fish has special cells on its tentacles called cnidoblasts.
These cnidoblasts contain toxins which is a protective mechanism shown by organisms belonging to the phylum Cnidaria.
On touching the jelly fish, this toxin is released which results in irritating of the body.


c. The members of Vertebrates possess notochord during embryonic development.
Thus, all vertebrates are chordates. However, the notochord is replaced by a cartilaginous or bony vertebral column in the adult.
Thus, all chordates are not vertebrates.


d. Balanoglossus is considered a connecting link between chordates and non chordates because it shows characteristics which are present in both the phylums.
For example, Balanoglossus shows the presence of notochord and pharyngeal gill slits which is a characteristic feature of chordates.
It also shows the presence of heart which is dorsal just like non chordates.


e. Reptiles are cold blooded organisms or poikilotherms which means they are not able to regulate their body temperatures.
Their body temperatures change with the change in the temperature of the environment.
For example, if the outer temperature rises their body temperature also rises and vice or versa.
This can be explained from the observation that when the temperatures drops, these reptiles bask themselves in the sun whereas when the temperatures are high, they would hide under the shades.

Question 7:

Answer the following questions by choosing the correct option.

a. Which special cells are present in the body of sponges (Porifera)?

1. Collar cells
2. Cnidoblasts
3. Germ cells
4. Ectodermal cells


b. Which of the following animal’s body shows bilateral symmetry?

1. Star fish
2. Jelly fish 
3. Earthworm
4. Sponge

c. Which of the following animals can regenerate it’s broken body part?

1. Cockroach
2. Frog
3. Sparrow
4. Star fish



d. Bat is included in which class?

1. Amphibia
2. Reptilia
3. Aves
4. Mammalia

ANSWER:

a. Collar cells are present in the body of sponges (Porifera).
b. Earthworm shows bilateral symmetry.
c. Star fish can regenerate it’s broken body part.
d. Bat is included in the class Mammalia.

Question 8:

Complete the following chart.


Question 9:

Complete the following chart.


Question 10:

Sketch, label and classify

Hydra, Jellyfish, Planaria, Roundworm, Butterfly, Earthworm, Octopus, Star fish, Shark, Frog, Wall lizard, Pigeon,


ANSWER:

Classification: 


1. Kingdom- Animalia

Phylum- Arthropda

Genus- Rhopalocera


2. Kingdom- Animalia

Phylum- Choradata

Class- Aves

Genus- Columba


3. Kingdom- Animalia

Phylum- Echinodermata

Genus- Asterias


4. Kingdom- Animalia

Phylum- Platyhelmenthis

Genus- Planaria


5. Kingdom- Animalia

Phylum- Choradata

Class- Chondrichthyes

Genus- Isurus


6. Kingdom- Animalia

Phylum- Chordata

Class- Amphibia

Genus- Rana


7. Kingdom- Animalia

Phylum- Aschelminthes

Genus- Ascaris


8. Kingdom- Animalia

Phylum- Coelenterata

Genus- Hydra


9. Kingdom- Animalia

Phylum- Mollusca

Genus- Octpous


10. Kingdom- Animalia

Phylum- Choradata

Class- Reptilia

Genus- Hemidactylus


Question 11:

Label the following.

ANSWER:


Chapter 5, Towards Green Energy, Science Part II, Solutions, for, Class 10, Maharashtra board, 2020, 2021,

Question 1

Remake the table taking into account relation between entries in three columns.

Solution


Question 2:

Which fuel is used in thermal power plant? What are the problems associated with this type of power generation?

ANSWER:

Coal is used in thermal power plant.
Problems associated with this type of power generation are:
Air pollution caused due to burning of coal:
Burning of coal emits gases like carbon dioxide, sulphur oxide and nitrogen oxide which are harmful to living beingsRelease of soot particles in the environment:
Along with the gases released due to burning of coal, soot particles are released in the environment which can cause fatal respiratory problems.
Coal is non-renewable source of energy. So, this method of power generation will put a limit on the availability of coal in future.

Question 3:

Other than thermal power plant, which power plants use thermal energy for power generation? In what different ways is the thermal energy obtained?

ANSWER:

Other than thermal power plant, nuclear power plants, solar power plants use thermal energy for power generation.
Different ways of generating thermal energy are:
Using fossil fuels:
By burning fossil fuels such as coal, petroleum, the chemical energy stored in them is converted into thermal energy.
Using natural gas: Chemical energy in natural gas is converted into thermal energy.
Using nuclear fuels: Controlled chain reaction in nuclear power plants releases huge amount of thermal energy.
Using solar energy: Solar energy can be reflected and absorbed in aborbers where it gets converted to thermal energy. 
Using geothermal energy: Underground water, sometimes, comes in contact with hot spots (where hot molten rocks are found), and thus steam is generated which is then collected via hot springs.
Thus, geothermal energy is converted to heat energy.

Question 4:

Which type/types of power generation involve maximum number of steps of energy conversion? In which power generation is the number minimum?

ANSWER:

 The types of power generation involving maximum number of steps of energy conversion are:
(i) Thermal energy based power generation:
It involves 5 steps of energy conversion.
Chemical energy in coal→thermal energy→kinetic energy in steam→kinetic energy in turbine→electrical energy.

(ii) Nuclear energy based power generation:
It also involves 5 steps of energy conversion.
Nuclear energy→thermal energy→kinetic energy in steam→kinetic energy in turbine→electrical energy.

The power generation using solar photovoltaic cell involves least number of steps of energy conversion. It involves only two steps of energy conversion.
Energy in sunlight→electric energy.

Question 5:

Solve the following crossword puzzle.

a. Maximum energy generation in india is done using….. energy.

b. …… energy is a renewable source of energy

c. Solar energy can be called…. energy.

d …. energy of wind is used in wind mills.

e. ….. energy of water in dams is used for generation of electricity.


ANSWER:


Question 6:

Explain the difference.

a. Conventional and Non-conventional Sources of energy.

b Thermal electricity generation and solar thermal electricity generation.

ANSWER:

B.

Thermal electricity generationSolar thermal electricity generation
It uses non-renewable source of energy for electricity generation such as fossil fuels, natural gas or nuclear fuels.It uses a renewable source of energy i.e. solar energy for electricity generation
This method of electricity generation is not environment friendly. It causes air pollution.
This is environment friendly method of electricity generation. It does not cause air pollution.
This method requires maintenance.This method does not require maintenance.

Question 7:

What is meant by green energy? Which energy sources can be called as green energy sources and why? Give examples.

ANSWER:

Green energy is that energy which does not pollute the environment and is renewable in nature.
The energy sources such as sunlight, wind, rain, tides, etc. can be called as green energy.
This is because these are readily available on Earth, can be naturally replenished and do not even harm the environment much.

Question 8:

Explain the following sentences.

a. Energy obtained from fossil fuels is not green energy.

b. Saving energy is the need of the hour.

ANSWER:

a. Fossil fuels are non renewable sources of energy. These are getting depleted rapidly. Also, the usage of the fossil fuels for energy generation adversely impacts the environment and living beings. Burning of fossil fuels like coal, natural gas etc. leads to emission of gases and soot particles in the environment which pollute the air and cause many respiratory diseases. For example, incomplete combustion of some fossil fuels leads to formation carbon monoxide which affects the health of living beings. Also, burning of fossil fuels releases carbon dioxide in the environment which is the main greenhouse gas. Thus, it can be said that energy obtained from fossil fuels is not green energy.

b. Yes, certainly energy conservation has become the need of the hour. We know our day to day life runs on electricity. Be it fans, lights, televisions, escalators, vehicles on roads or water supply to our homes, each and everything requires energy- “The Electrical Energy” for its working. Even the technology advancement has made it possible to supply electricity to most remote places. Thus, to produce such huge amount of electrical energy, we are getting more and more dependent on non-renewable sources of energy such as coal, petroleum, etc. It is observed that the rate at which these fuels are consumed is much greater than at which it is produced. So, if it continues like this, a day will come when we would get deprived of these sources of energy and thus will not even get the basic amenities of life. So, take a pledge to not waste energy wherever possible for the betterment of our and future generations.

Question 9

Answer the following questions.

a. How can we get the required amount of energy by connecting solar panels?

b. What are the advantages and limitations of solar energy?

ANSWER:

a. Many identical solar cells connected together forms a solar panel.
Now, many such solar panels are connected in series in a form of solar string to get required voltage.
Also, many such identical solar strings are connected in parallel to get the required current.
Hence, in this way we get the required amount of energy by connecting solar panels.

b. Advantages of solar energy:
Solar energy is green energy i.e. it is renewable and does not cause pollution.
Solar panels for the generation of electricity requires less maintenance.
With the help of solar energy, electricity is possible to be generated even in the most remote, inaccessible locations where electric power lines cannot be laid.
Limitations of solar energy: 
Electricity generation based on solar energy is weather dependent and hence it is less reliable.
In winter and on cloudy days, the production becomes less. 
The whole set-up of the panels requires lots of space to generate considerable amount of electricity. 
The initial cost of a solar panel is sufficiently high.

Question 10:

Explain with diagram step-by-step energy conversion ina. Thermal power plantb. Nuclear Power Plant.c. Solar thermal power plantd. Hydroelectric power plant

ANSWER:

a. Water is heated in a boiler. Using the thermal energy released due to burning of coal, steam of very high temperature and pressureis generated. The energy in the steam drives the turbine. Thus, the generator connected to the turbine rotates and electrical energy is produced.

Chemical energy in coal→Thermal energy→Kinetic energy in steam→Kinetic energy in turbine→Electrical energy

b. Nuclear power plants consist of nuclear reactors. These reactors use uranium rods as fuel and heat is generated by the process of nuclear fission. Neutrons smash into the nucleus of the uranium atoms, which roughly split into half and release energy in the form of heat. Carbon dioxide gas is pumped through the reactor to take the heat away. The hot gas then heats water to form steam. This steam drives the turbines of generators to produce electricity.
Thus, the steps of energy conversion are:
Nuclear energy→Thermal energy→Kinetic energy in steam→Kinetic energy in turbine→Electrical energy.

c. Following energy conversion takes place in the solar thermal power plant:

Thermal energy in radiation→Kinetic energy in steam→Kinetic energy in turbine→Electrical energy.

d. In a hydroelectric power plant, the potential energy in water stored in dam is converted into kinetic energy of water. Fast flowing water is brought from the dam to the turbine at the bottom of the dam. The kinetic energy of the flowing water drives the turbine. The turbine in turn drives a generator to generate electricity.
Potential energy in water→Kinetic energy in flowing water→Kinetic energy in turbine→Electrical energy.

Question 11:

Give scientific reasons

a. The construction of turbine is different for different types of power plants.

b. It is absolutely necessary to control the fission reaction in nuclear power plants.

c. Hydroelectric energy, solar energy and wind energy are called renewable energies.

d. It is possible to produce energy from mW to MW using solar photovoltaic cells.

ANSWER:

a. The construction of turbine is different for different types of power plants. This depends on the type of energy source used for driving the turbine. Like in thermal power plants, steam turbine is used whereas in hydro-power plant, water turbine is used.


b. If fission reaction in nuclear power plants is not controlled, then enormous amount of heat released during this process will lead to explosion of the plant and cause fatal destruction to the environment and mankind. Thus, it is absolutely necessary to control the fission reaction in nuclear power plants.


c. Hydroelectric energy, solar energy and wind energy are called renewable energies because they are abundant in nature and can be regenerated or replenished again and again. These will never extinct even with their excessive use.


d. Solar photovoltaic cells can be arranged according to the requirement of electric power. If power requirement is within mW, use of few number of photovoltaic cells will be able to achieve this much power. But, if the requirement of power is in MW, then large number of cells are grouped together to form a solar panel. Then, large number of solar panels are connected in series and parallel to get the required electric power. Thus, it is possible to produce energy from mW to MW using solar photovoltaic cells.

Question 12:

Draw a schematic diagram of solar thermal electric energy generation.

ANSWER:

The schematic diagram of solar thermal electric energy generation is as follows:


Question 13:

Give your opinion about whether hydroelectric plants are environment friendly or not?

ANSWER:

No waste products and harmful gases are released in water bodies and atmosphere when power is generated using hydroelectric power plants. Also, water is available in plenty on Earth and is renewable. Hence, there is no fear of this energy source dying out. Thus, it has no harmful effects on the environment and hence is environment friendly.

Question 14:

Draw neat and labelled diagrams.

ANSWER:

a. Energy transformation in solar thermal electric energy generation.

b. One solar panel produces a potential difference of 18 V and current of 3 A. Describe how you can obtain a potential difference of 72 Volts and current of 9 A with a solar array using solar panels.

You can use sign of a battery for a solar panel.


Thermal energy in radiation→Kinetic energy in steam→Kinetic energy in turbine→Electrical energy.


b. We can obtain a potential difference of 72 V by forming a string of 5 solar panels in series. Now, to obtain current of 9 A, connect 3 such identical strings in parallel.

The same has been shown below.


Question 15:

Write short note on Electrical energy generation and environment.

ANSWER:

Today electrical energy generation has become the need of the hour.

We cannot imagine our life without electricity.

We have been able to generate electrical energy by various methods.

In these methods, a generator is present which works on the principle of electromagnetic induction.

A turbine is used to rotate this generator and this turbine itself is rotated with the help of an energy source.

This energy source can be a renewable source such as wind, sunlight, nuclear fuels etc.

as well as non-renewable sources such as coal, petrol, water etc. The energy sources such as wind, sunlight have proved to be green sources as they do not pollute the environment and are economical too.

But the use of fossil fuels such as natural gas, coal, nuclear energy etc.

as energy source has harmful effects on the environment.
The harmful radiation emitted from the nuclear waste has fatal effect on the environment and humans.

Even the release of soot particles and various greenhouse gases such as carbon dioxide, carbon monoxide on burning or incomplete burning of fossil fuels affects the health of living beings as well as the environment adversely.

Also, the release of these greenhouse gases is day by day increasing the danger of global warming.

We need to as soon as possible find suitable environment friendly substitutes to fossil fuels to save our


CBSE, latest,  News, CBSE time table, for, Class 10, and, Class 12, board exam, will be released, on the official website, cbse.nic.in.,

New Delhi:

CBSE Time Table 2021: The Central Board of Secondary Education has not made any official announcement regarding CBSE board exam date sheet 2021 yet.

Last year , the board conducted final exams from February-March and announced dates in January. Amid the demands for postponement of board exams, students on social media are asking CBSE and the Education Ministry for “clarity” on when the exams will be held next year.

With No Announcement Yet, Students Want “Clarity” On CBSE Board Exam 2021.

CBSE Class 12 Board Exams 2021: Check Sample Papers, Marking Scheme. 👈 Click here

Chapter 4, Environmental Management, Science Part II, Solutions, for, Class 10, Science, Maharashtra board,
Question 1:

Reorganize the following food chain. Describe the ecosystem to which it belongs. 


Grasshopper – Snake – Paddy field – Eagle – Frog.


ANSWER:


Paddy field – Grasshopper – Frog – Snake – Eagle.


Paddy field represents the primary producer which are plants.


Grasshopper is a primary consumer.

Primary consumers are organisms that eat the primary producers and are usually herbivores.


Frog is a secondary consumer.

Secondary consumers are organisms that eat the primary consumers and are generally meat-eaters/carnivores.


Snake is a tertiary consumer.

Tertiary consumers are organisms that eat the secondary consumers.

These organisms are carnivore-eating carnivores, like snakes or big fish.


Eagle is a quaternary consumers and in this case it is the apex consumer because it occupies the highest position in the food chain. 



Question 2:

Explain the statement- ‘we have got this Earth planet on lease from our future generations and not as an ancestral property from our ancestors.’


ANSWER:


The above statement refers to the fact that earth belongs to everyone, from our ancestors to our future generations.

It indicates towards the point that the planet earth should be protected and conserved in the same way as by our ancestors, so that it can be passed on to our future generations.

It highlights an underlying problem which is the overexploitation of resources by the present generation which could eventually lead to the destruction of life on earth.

The planet earth can be protected for future generations by following the path of sustainable development.

Sustainable development means that development should be such that it can be sustained for a longer period of time and must cater to the needs of the coming generations.

It is mostly used in terms of the non-renewable sources of energy, which face depletion because of over-use by human beings.

Sustainable development seeks to promote a judicious use of non-renewable energy sources such as coal and petroleum so that they do not get depleted beforehand and our future generations do not have these resources at their disposal.

Sustainable development thus means developing in such a way that not only our present but our future is also secured.



Question 3:

Write short notes.


a. Environmental Conservation.

b. Chipko Movement of Bishnoi.

c. Biodiversity.

d. Sacred Groves.

e. Disaster and its management.


ANSWER:


a. Environmental conservation is a broad term which refers to the actions we take in order to protect our planet and conserve its natural resources. We are very well aware of the fact that the human life on earth is supported by the various components of the environment. There is a direct relationship between environment and life on earth. Any kind of harm or disruption to the environment will directly and indirectly affect the life of organisms on this earth. We need to understand that natural resources should be used in a sustainable manner and not to fulfill our greeds.
Environmental conservation implies to the conservation of forests, water resources, mineral resources etc. There are various projects which are being carried out at different levels with respect to environment conservation. These programmes are carried out by government organisations, NGO’s, RWA’s, schools, colleges etc. The aim of these programmes is to promote the conservation of environment from the grassroots level.


 
b. The Chipko Movement started in the 1970s in Garhwal in Uttarakhand. It was a socio-ecological movement which followed the Gandhian ideology of satyagraha for the protection of trees from cutting. Chipko, in Hindi, literally means ‘to stick’. Under the movement, people used to hug the trees in order to protect them from being felled. The movement mobilized villagers by making them aware about the after effects of destruction of forests. It was a great success and soon spread all over India. It was because of Chipko Movement that the government of India realized the importance of formulating wildlife conservation plans and policies in order to protect the biodiversity of the country. 



c. Biodiversity refers to the combined diversity at all levels of biological organisation. It includes genetic diversity, species diversity and ecological diversity.

Importance of biodiversity:

(i) A wide range of materials such as fibres, dyes, resins are obtained from plants.

(ii) A variety of plants and animals are utilised as sources of food.

(iii) Medicinal plants act as sources of drugs.

(iv) Plants and animals also have a cultural and aesthetic value.



d. The sacred groves are forest fragments which are highly protected by certain communities because they are of religious importance to the communities. These can be considered as sanctuaries which are protected by the society and not by the government organisations. More than 13000 sacred groves have been identified all over India.



e. Any natural or man made event which has a negative impact on life, property and livelihood and causes permanent changes to environment, ecosystem and human society is termed as a disaster. Natural disasters: Any adverse event which occurs as a result of natural processes of earth is called natural disaster for example: cyclones, earthquakes, storms, tsunamis, etc.
Man made disasters: Unlike natural disasters, which are influenced by natural forces, man made disasters are caused due to negligence of humans. Gas leaks, oil spills, nuclear meltdown or leakage of radiation, industrial fires, transport accidents, terrorism, epidemics and biological warfare are examples of man made disasters. 
The damage caused by disasters can be reduced by making ourselves prepared in disaster management. Disaster management is the strategy and course of action to be executed at the time of any such disaster to save as much life as possible. 
This includes:

  1. Improving tolerance
  2. Preventing losses and dangers
  3. Providing relief to the affected people
  4. Preparing for actions to be taken at the time of disaster
  5. Assessing the damage caused
  6. Arrangement of rescue for the affected
  7. Rehabilitation and rebuilding the affected area

Question 4:

How will you justify that overcoming the pollution is a powerful way of environmental management?


ANSWER:


We know that the major cause of environmental damage is pollution.

Pollution of air, water bodies, soil etc.

all contribute to various environmental problems.

The continuous increase in pollution has made the environment nearly unfit for us.

This can largely be attributed to the rapid rate at which trees are being cut.

In the absence of trees, the level of carbon dioxide in the atmosphere increases, adding to the problem of global warming.

Moreover, the emission of carbon monoxide, hydrocarbons and other such gases, from vehicles and factories, is rapidly polluting the air making it even difficult to breathe.


Pollution of water bodies have resulted in the death of aquatic life and making most of the water bodies unfit for human and animal use.


All the above points highlight the fact that pollution is one of the causes of environmental degradation.

Environmental management can help solve this issue by efficiently managing the problems associated with pollution.

We need to remember that nature is a treasure which needs to be preserved for our own survival.

If we do not pay attention to this problem and make efforts to preserve our environment, this wonderful earth would soon cease to exist.



Question 5:

Which projects will you run in relation to environmental conservation? How?

ANSWER:


Environmental conservation is a broad term which refers to the actions we take in order to protect our planet and conserve its natural resources. Environment conservation can have various components like conservation of forests, conservation of water resources etc.

There are various projects which can be carried out to conserve our environment: 


Water conservation-  Conservation of water is of utmost importance for human survival because almost all forms of life depend on water. Conservation of water is essential for securing food grain production and sustaining various life-forms. In order to conserve water we can run programmes on various levels to bring awareness about water conservation and its methods. The most talked about method is rain water harvesting. We can persuade people to practice rain water harvesting and the government can provide loans and expert advice for this purpose. 


Forest conservation- Forest conservation not only deals with conservation of trees of a forest but it also implies to the protection of wildlife which exists there. Forests are a huge resource of wood and other products which is why they are exploited at a greater scale. In order to protect forests, the government and the public needs to work in harmony. We need to start projects which you aimed at recycling of products like paper etc. so that less trees are cut down. We need to take responsibilities that less of forest cover is destroyed for urbanisation projects.
We need to start projects which highlight the importance of sustainable development and how we can achieve that.


Question 6:

Answer the following.


a. Write the factors affecting environment.

b. Why does the human beings have important place in environment?

c. Write the types and examples of biodiversity.

d. How biodiversity can be conserved?

e. What do we learn from the story of Jadav Molai Peyang?

f. Write the names of biodiversity hot spots.

g. Which are the reasons for endangering the many species of plants and animals? How can we save those?


ANSWER:


a. The factors which affect the environment are grouped into two categories- biotic and abiotic factors. 
Biotic factors refer to the living components of an ecosystem like animals and plants. 
Abiotic factors refer to the non living components of an ecosystem, for example, sunlight, temperature, air etc.
The biotic and abiotic factors together affect the environment as both are connected to each other. Abiotic factors are required for the existence and survival of organisms.


b. There is an inter relationship between humans and environment which means humans and environment are interconnected. The existence of humans is not possible without striking a balance with the environment. Humans developed ways to use these natural resources for their existence, however when these needs turned into greed, it resulted in over exploitation of resources. Over exploitation of resources by humans have threatened the existence of other species as well, resulting in their extinction. Various problems like global warming, changed weather patterns, water scarcity etc. are the results of human activities. These problems highlight the fact that how important is the role of humans with respect to the environment. If human activities are controlled and an effort is made to make harmony with nature, it is most probable we can revert these environmental changes and if we fail to do so, it could have devastating effects.


C. There are 3 types of diversity which are as follows:


Genetic diversity: Genetic diversity refers to the diversity which occurs among the organisms of same species. For example, the diversity which is found among humans, each human being is different from another.


Species diversity: Species diversity refers to the innumerable species of organisms which are found in nature ranging from plants, animals to microbes.
Ecosystem diversity: Ecosystem diversity refers to the various kinds of ecosystem which are found in a region. Each ecosystem will have its own characteristic plants, animals, abiotic factors etc. 



d. Two approaches followed for the conservation of biodiversity are:

  1. In-situ conservation: In order to conserve biodiversity better, biodiversity hotspots all around the world have been identified and protected. In India, biosphere reserves, wildlife sanctuaries, and national parks have been developed for this purpose.
  1. Ex-situ conservation: The threatened species of plants and animals are taken out of their habitats and are kept in special settings such as zoological parks, botanical gardens, and wildlife parks. Nowadays, the gametes of endangered species can be preserved by methods such as cryopreservation. They can also be fertilized in-vitro followed by propagation through tissue culture methods. Similarly, seeds can be preserved in seed banks.

e. Jadav Molai Peyang was a nomadic tribe born in Assam. There is a jungle which has been named on his name to hounour his hardwork. After a flood affected the areas of Assam, Jadav started a reforestation process by planting 20 bamboo plants. This initiative was then supported by the Assam government and with the hardwork of Jadav and the government, the barren area witnessed the forest cover over the 1360 acres. His contrbution to the environment was acknowleged by honouring him with the ‘Padmashree’ award. His story gives us a message that a single person can bring about a big change and it is the will which is required to do so.



f. Biodiversity hotspots are regions with high species richness and high degree of endemism. Endemism is the indigenousness of a species to a particular region. Western Ghats, Sri Lanka, Himalaya and Indo-Burma are the high biodiversity regions that cover India.



g. The last 20 years have seen the loss of 27 species. Some of the causes of this loss are:

  1. Habitat loss and fragmentation: This is the major cause for loss of biodiversity. Habitat destruction is caused by human activities such as deforestation and increasing pollution, leading to the loss of many plants and animals. Habitat fragmentation is the breaking up of habitat of a particular species into fragments.
  1. Over-exploitation: Humans, because of their greed and increased exploitation of natural resources, have contributed to the endangerment of commercially important species of plants and animals. Species such as the Steller’s sea cow and passenger pigeons have become extinct as a result of over-exploitation by humans.
  2. Co-extinction: When plants or animals become extinct, other plants or animals that are dependant on it in an obligatory way also become extinct.

Endangered plant and animal species can be saved by adopting methods which do not disturb their environment. We need to protect the habitats in which they survive and also protect them from poachers and hunters. Lot of steps are being taken at personal and public level to ensure their protection.



Question 7:What are the meanings of following symbols? Write your role accordingly?

ANSWER:

Symbol 1 represents recycle.

This sign is seen on various packaged food materials. Recycling is the process in which a substance that has been discarded is reprocessed to make the same or a different substance. It is one of the methods to conserve our environment, for example recycling of paper saves several others trees from being cut down. Also, chemicals that are produced at the time

of manufacturing paper are directly released into rivers and lakes. Therefore, recycling of paper will not only prevent deforestation but also prevent water pollution.


Symbol 2 represents water conservation.

Water conservation refers to the act of conserving water with the help of various methods such as rain water harvesting.

Conservation of water is essential for maintaining a proper hydrological cycle, ensuring timely rainfall and maintaining the availability of fresh water in rivers and other sources.

Conservation of water is essential for securing food grain production and sustaining various life-forms.

Water can be conserved by various methods.

The most effective means of conserving water is rainwater harvesting, which involves collecting rainwater and storing it for further use.

Water can also be conserved by checking our day-to-day habits and ensuring that there is no wastage of water.

Innovative irrigation techniques such as drip irrigation also help in water conservation to a great extent.


Symbol 3 represents solar pannels.

Solar energy can be harnessed with the help of solar cells. Several solar cells are connected together to form a solar panel. Solar panels devices are used to convert thermal energy of sun into electric energy.

There are various reasons for which solar energy is being prefered over other sources:

  1. being a tropical country India receives abundant sunlight throughout the year as the number of sunny days across a large geographical portion of country is around 300.
  2. it requires less investment in infrastructure as compared to other forms of energy.
  3. solar energy can be utilised for rural electrification and irrigation through solar powered water pumping system.
  4. it will eventually reduce the dependance upon fossils fuels hence will help in the conservation of environment.

Chapter 3, Life Processes In Living Organisms Part 2, Science Part II, Solutions, for, Class 10, Maharashtra board,

Complete the following chart.

Asexual reproductionSexual reproduction
1. Reproduction that occurs with the help of somatic cells is called as asexual reproduction.1. ………………………………………..………………………………………….…………………………………………………
2. ………………………………………… …………………………………..2. Male and female parent are necessary for sexual reproduction.
3. This reproduction occurs with the help of mitosis only.3. ……………………………………… ……………………………………………….
4. …………………………………………… ………………………………………….…4. New individual formed by this method is genetically different from parents.
5. Asexual reproduction occurs in different individuals by various methods like binary fission, multiple fission, budding, fragmentation, regeneration, vegetative propagation, spore production, etc.5. ………………………………………….. ………………………………………….…  

ANSWER:

Asexual reproductionSexual reproduction
1. Reproduction that occurs with the help of somatic cells is called as asexual reproduction.1.  Reproduction that occurs with the help of germ cells is called sexual reproduction.
2. Both the parents are not required for asexual reproduction. It is uniparentalreproduction.2. Male and female parent are necessary for sexual reproduction.
3. This reproduction occurs with the help of mitosis only.3. This reproduction occurs with the help of both meiosis and mitosis.
4. New individual formed by this method is genetically identical to parents.4. New individual formed by this method is genetically different from parents.
5. Asexual reproduction occurs in different individuals by various methods like binary fission, multiple fission, budding, fragmentation, regeneration, vegetative propagation, spore production, etc.5. exual reproduction occurs in various organisms like microbes, plants, animals and humans. It involves two main processes- gamete formation and fertilization.

Fill in the blanks.

a. In humans, sperm production occurs in the organ —————-.

b. In humans, —— chromosome is responsible for maleness.

c. In male and female reproductive system of human, ————- gland is same.

d. Implantation of embryo occurs in ——

e. ———- type of reproduction occurs without fusion of gametes.

f. Body breaks up into several fragments and each fragment starts to live as a new individual. This is — — — — — — — type of reproduction.

g. Pollen grains are formed by — —– — — — division in locules of anthers.

ANSWER:

a. In humans, sperm production occurs in the organ testes.

b. In humans, Y chromosome is responsible for maleness.

c. In male and female reproductive system of human, bulbourethral gland is same.

d. Implantation of embryo occurs in uterus.

e. Asexual type of reproduction occurs without fusion of gametes.

f. Body breaks up into several fragments and each fragment starts to live as a new individual. This is fragmentation type of reproduction.g. Pollen grains are formed by meiotic division in locules of anthers.


Complete the paragraph with the help of words given in the bracket. (Luteinizing hormone, endometrium of uterus, follicle stimulating hormone, estrogen, progesterone, corpus luteum)


Growth of follicles present in the ovary occurs under the effect of —– This follicle secretes estrogen. — — – — — — grows / regenerates under the effect of estrogen. Under the effect of — —, fully grown up follicle bursts, ovulation occurs and — — — — is formed from remaining part of follicle. It secrets — — — — and — — — — –. Under the effect of these hormones, glands of — — — — are activated and it becomes ready for implantation.

ANSWER:

Growth of follicles present in the ovary occurs under the effect of follicle stimulating hormone. This follicle secretes estrogen. Endometrium of uterus grows/regenerates under the effect of estrogen. Under the effect of luteinizing hormone, fully grown up follicle bursts, ovulation occurs and corpus luteum is formed from the remaining part of follicle. It secretes progesterone and estrogen. Under the effect of these hormones, glands of endometrium of the uterus are activated and it becomes ready for implantation.


Answer the following questions in short.

a. Explain with examples types of asexual reproduction in unicellular organism.

b. Explain the concept of IVF.

c. Which precautions will you follow to maintain the reproductive health?

d. What is menstrual cycle? Describe it in brief.

ANSWER:

a. Asexual reproduction in unicellular organisms can be of three types:

Binary fission: Binary fission is the splitting of parent organisms into two halves, each of which develops to form a complete daughter cell.

For example, Amoeba reproduces asexually by the process of binary fission.

In Amoeba,binary fission begins with the division of the nucleus.

This is followed by the division of the cytoplasm and the cell.

Each part receives a portion of the nucleus. Finally, two cells are formed from one parent Amoeba.

Multiple fission − Multiple fission is also seen in Amoeba. In this method, the parent microbe divides into many daughter microbes.

Amoeba shows multiple fission under adverse conditions. It covers itself in a protective covering and forms a structure known as cyst.

Inside the cyst, the nuclei undergo repetitive nuclear division followed by cytoplasmic division and result in the formation of amoebules.

These amoebules are released together when the conditions turn favourable.


Budding − In this method, a bud develops as an outgrowth from parent body.

This developing bud detaches from the parent body and the daughter individual develops further.

For example, yeast reproduces asexually through the method of budding.

During this process, small bulb-like projections (called buds) start coming out of the yeast cell.

These buds gradually grow in size and get detached from the parent cell to form a new yeast cell.

The new yeast cell then grows and becomes mature to form more yeast cells.



b. Many couples all over the world are unable to produce children due to various reasons. These couples can be assisted to have children through techniques called assisted reproductive technologies (ART).

IVF is one such form of ART which includes different methods that can be a boon for childless couples:

Solution

Surrogacy– This is a technique which is used for women who face problem in implantation of embryo in uterus.

In this technique the donor of the oocyte is the women itself who has problem in implanting the embryo in the uterus.

The collected oocyte is fertilized with the sperm of her husband in a test tube.

The embryo which is obtained after fertilization is implanted in the uterus of another female who is called the surrogate mother.

ZIFT − It stands for zygote intra fallopian transfer.

In ZIFT, the sperm from a donor male and the ova from a donor female are fused in the laboratory.

The zygote so formed is transferred into the fallopian tube at the 8 blastomeres stage.

IUT − It stands for intra uterine transfer. In this technique, embryos with more than 8 blastomeres are transferred into the uterus.


GIFT − It stands for gamete intra fallopian transfer.

In GIFT, females who cannot produce ovum, but can provide suitable conditions for the fertilisation of ovum, are provided with ovum from a donor.


ICSI − It stands for intra cytoplasmic sperm injection.

In this method, sperm is directly injected into the cytoplasm of the ovum.


Artificial insemination − In this technique, the semen collected from the husband or a donor is injected into the vagina or uterus.

This cures the infertility arising from the inability of the male partner to ejaculate, or due to low sperm count.


c. Precautions which should be taken in order to maintain good reproductive health are:

  1. eat a balanced and nutritional diet
  2. maintain personal hygiene
  3. take adequate physical exercise
  4. avoid taking any drugs.

d.  Menstrual cycle is the reproductive cycle in all primates and begins at puberty (menarche).

  1. In human females, menstruation occurs once in 28 to 29 days. The cycle of events starting from one menstruation till the next one is called the menstrual cycle.
  2. During the middle of the menstrual cycle, one ovum is released (ovulation).
  3. The cycle starts with the menstrual flow (3 to 5 days), caused due to the breakdown of the endometrium of the uterus. Blood vessels in liquid state are discharged, but this occurs only when the ovum is not fertilised.
  4. It is followed by the follicular phase. In this phase, the primary follicles mature into the Graafian follicles. This causes the regeneration of the endometrium, follicular growth, and the growing follicles produce oestrogen.
  5. The LH and FSH are at their peak in the middle of the cycle (14th day) and cause the rupture of the Graafian follicles to release ovum. This phase is called the ovulatory phase.
  6. In the absence of fertilisation, the corpus luteum degenerates, thereby causing the disintegration of the endometrium and the start of a new cycle.

In case of sexual reproduction, newborn show similarities about characters. Explain this statement with suitable examples.

ANSWER:

Sexual reproduction involves the fusion of two types of gametes i.e., the male and the female gametes.

The zygote formed contains a fusion of both the sperm nucleus and the egg nucleus.

Due to this, the new individual has characteristics which are similar to both the parents while some characteristics which are different from both the parents.

Thus, the new individual formed from sexual reproduction inherits the characteristics of both the parents.

For example, if the father has black hair while the mother has brown hair, the chances are that their offspring may have either black or brown hair. 


Sketch the labeled diagrams:

a. Human male reproductive system

b. Human female reproductive system

c. Flower with its sexual reproductive organs

d. Menstrual cycle

ANSWER:





Give the names.

a. Hormones related with male reproductive system.

b. Hormones secreted by ovary of female reproductive system.

c. Types of twins.

d. Any two sexual diseases.

e. Methods of family planning.

ANSWER:

a. Hormones related with male reproductive system– testosterone

b. Hormones secreted by ovary of female reproductive system– estrogen and progesterone

c. Types of twins– Monozygotic and dizygotic twins

d. Any two sexual diseases– AIDS and Gonorrhea

e. Methods of family planning– Oral pills, condoms, IUD’s


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Gender of child is determined by the male partner of couple. Explain with reasons whether this statement is true or false.

ANSWER:

Human females have two X chromosomes (XX) and human males have one X and one Y chromosome (XY).

Therefore, the eggs produced by females have only X chromosomes while the sperms produced by males can have either X or Y chromosome.

If an unfertilised egg fuses with a sperm containing X chromosome, then it gives rise to a girl child having two X chromosomes.

If an unfertilised egg fuses with a sperm containing Y chromosome, then it gives rise to a male child having one X and one Y chromosome.


Explain asexual reproduction in plants.

ANSWER:

Asexual reproduction is the process by which a plant gives rise to a new plant without producing seeds or spores.

Asexual reproduction in plants occur by vegetative propogation.

The development of a new plant from the vegetative part of a plant like stem, root or leaf is known as vegetative propagation.

The various methods of vegetative propagation are:


From underground stem: A potato plant has an underground stem known as the tuber. It has many buds called eyes. A vegetative bud consists of a short stem, around which immature overlapping leaves are present in a folded state. A bud can give rise to a new plant through asexual reproduction.


Rhizome: The underground stem of ginger is known as the rhizome which is capable of giving rise to a new plant. Corm is the underground stem as found in Gladiolus. It can also be used for vegetative propagation.


Through leaves: Leaves perform the function of photosynthesis. However, they can take part in asexual reproduction as well. In some plants, leaves can give rise to a new plant asexually. For example, the leaves of the plant Bryophyllum contain buds on its margins. These buds give rise to a new plant through asexual reproduction.


From aerial stem: In certain plants, a slender stem arises from the base of the plant and touches the soil, it develops roots and buds at the point of contact with the soil and gives rise to new plants. When the new plant is old enough the stem connecting it to the parent plant withers away.


Modern techniques like surrogate mother, sperm bank and IVF technique will help the human beings. Justify this statement.

ANSWER:

Many couples all over the world are unable to produce children because of various reasons like congenital diseases, drugs, immunological and psychological factors. Such couples can be assisted to have children through techniques called assisted reproductive technologies (ART).  IVF is one such ART and include the following techniques:

  • ZIFT − It stands for zygote intra fallopian transfer. In ZIFT, the sperm from a donor male and ova from a donor female are fused in the laboratory. The zygote so formed is transferred into the fallopian tube at the 8 blastomeres stage.
  • IUT − It stands for intra uterine transfer. In this technique, embryos with more than 8 blastomeres are transferred into the uterus.
  • GIFT − It stands for gamete intra fallopian transfer. In GIFT, females who cannot produce ovum, but can provide suitable conditions for the fertilisation of ovum, are provided with ovum from a donor.
  • ICSI − It stands for intra cytoplasmic sperm injection. In this method, sperm is directly injected into the cytoplasm of the ovum.
  • Artificial insemination − In this technique, the semen collected from the husband or a donor is injected into the vagina or uterus. This cures the infertility arising from the inability of the male partner to ejaculate, or due to low sperm count.
  • Surrogacy – Surrogacy is another method which is used for women who face problem in implantation of embryo in uterus. In this technique the donor of the oocyte is the women itself who has problem in implanting the embryo in the uterus. The collected oocyte is fertilized with the sperm of her husband in a test tube. The embryo which is obtained after fertilization is implanted in the uterus of another female who is called the surrogate mother.
  • Sperm bank – It is a new concept which is similar to blood banks. Sperms are collected from the male donors after a thorough medical checkup and stored for future use. These sperms are used to fertilize the ovum of the women and then this fertilised ovum is implanted in the uterus of the same women.

Explain sexual reproduction in plants.

ANSWER:

  1. In sexually reproducing plants, flowers function as the reproductive organs.
  2. In flowers, male organ is the stamen and female organ is the carpel.
  3. Flowers which have both the male and female organs i.e. stamens and carpels are called bisexual flowers whereas flowers which have either male or female organs are called unisexual.
  4. Male gametes called pollen grains are produced by stamen, and carpels produce female gametes called ovules or egg cells inside ovaries.
  5. Fertilization takes place in the ovule where the egg cell and pollen grain fuse.
  6. This fertilized egg cell later develops into an embryo and the entire ovule gets converted into a seed.
  7. Under favourable conditions, the seed germinates to give rise to a new plant.

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