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NCERT Solutions for Class 12 Biology Chapter 10 Microbes in Human Welfare

NCERT Solutions for Class 12 Biology Chapter 10 Microbes in Human Welfare

Edited By Irshad Anwar | Updated on Sep 19, 2023 02:21 PM IST | #CBSE Class 12th

NCERT Solutions for Class 12 Biology Chapter 10 Microbes in Human Welfare: Microbes are a very important component of life on earth. In the Class 12 Biology Chapter 10 NCERT Solutions, you will see questions related to microbes in household products, Microbes in Industrial Products, and Microbes in Sewage Treatment. In the solutions for NCERT Class 12 Biology Chapter 10 Microbes in Human Welfare, you will learn interesting facts about how all microbes are not pathogenic. According to the Microbes in Human Welfare NCERT Solutions, even many microbes are very useful to human beings. NCERT Solutions for Class 12 Biology Chapter 10 PDF download will be helpful in developing concepts from the questions asked in the Biology Textbook. If you are looking for the answers to any other class from 6–12, then NCERT Solutions are there for you. By referring to the NCERT Solutions for Class 12 Biology, you will be able to understand all the important concepts.

Chapter 10 Biology Class 12 Solutions for Microbes in Human Welfare NCERT explains how we use microbes and microbial-derived products almost every day. Bacteria called lactic acid bacteria (LAB) grow in milk to convert it into curd. The dough, which is used to make bread, is fermented by a yeast called Saccharomyces cerevisiae. In order to study for the board exams, students can use these NCERT Solutions for Class 12. Additionally, these answers are available for free download in PDF format. It provides answers in accordance with the most recent CBSE Syllabus (2023–24) and the NCERT Textbook.

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According to the CBSE Syllabus 2023-24, this chapter has been renumbered as Chapter 8.

NCERT Solutions for Class 12 Biology Microbes in Human Welfare

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NCERT Solutions for Class 12 Biology Microbes in Human Welfare: Solved Exercise Questions:

Microbes in Human Welfare NCERT Solutions are given below in the sequence as per the NCERT Textbook data:

Microbes in Human Welfare Class 12 Questions and Answers

Q1. Bacteria cannot be seen with the naked eyes, but these can be seen with the help of a microscope. If you have to carry a sample from your home to your biology laboratory to demonstrate the presence of microbes with the help of a microscope, which sample would you carry and why?

Answer:

If I have to carry a sample from your home to your biology laboratory to demonstrate the presence of microbes with the help of a microscope, then in order to demonstrate the presence of microbes, we can take curd from our homes as curd contains millions of bacteria.

Q2. Give examples to prove that microbes release gases during metabolism.

Answer:

When any bacteria grow on any material, it uses that material as the substratum to acquire food and starts metabolising that material to release some products. For example, the puffed appearance of dough of dosa is due to the release of gases like CO2 by the bacteria growing on them. Large holes on Swiss cheeses are also due to the release of gases produced by bacteria growing on them

Microbes in Human Welfare Class 12 Questions and Answers:

Q3. In which food would you find lactic acid bacteria? Mention some of their useful applications.

Answer:

Lactic acid bacteria (LAB) is found in curd. The useful applications of LAB are as follows:

1. These bacteria can convert milk into curd.

2. LAB are also found in our stomach to check the growth of harmful bacteria in our stomach.

3. LAB increases the amount of vitamin B12 in curd. Thus, it makes curd nutritious.

Q4. Name some traditional Indian foods made of wheat, rice and Bengal gram (or their products) which involve the use of microbes.

Answer:

Indian food made of Wheat- Bread, bhatura, cake

Indian food made of rice- Idli, dosa, uttapam

Indian food made of Bengal gram- Dhokla, Khandvi

Microbes in Human Welfare Class 12 Solutions

Q5. In which way have microbes played a major role in controlling diseases caused by harmful bacteria?

Answer:

Role of microbes in controlling diseases caused by harmful bacteria:

Microbes are used to produce antibiotics. The antibiotics are chemical substances that are obtained from microorganisms and that kill other microorganisms like bacteria. The first antibiotic was penicillin and it was obtained from fungus Penicillium notatum. Penicillin acts by degrading the cell wall of bacteria.

Q6. Name any two species of fungus, which are used in the production of the antibiotics.

Answer:

Penicillium notatum and Penicillium chrysogenum are used for preparing Penicillin.

Microbes in Human Welfare Class 12 Solutions:

Q7. What is sewage? In which way can sewage be harmful to us?

Answer:

The municipal wastewater that is drained into sewers and drains is known as sewage. It contains a large amount of organic matter, microbes, human excreta etc. When sewage is not treated properly, it degrades the quality of water and acts as a breeding site for the mosquitoes. This may lead to diseases like dengue, malaria etc in nearby communities. Thus sewage can be harmful to us.

Microbes in Human Welfare Class 12 NCERT Solutions

Q8. What is the key difference between primary and secondary sewage treatment?

Answer:

The differences between the primary and secondary treatment of sewage are as follows:

Primary sewage treatment Secondary sewage treatment
Primary sewage treatment is a mechanical process that removes solid waste materials Secondary sewage treatment is a biological process in which waste materials are enzymatically treated by bacteria and other microbes
It is a less expensive and simple process It is an expensive and complicated process
Q9. Do you think microbes can also be used as a source of energy? If yes, how?

Answer:

Yes, microbes can be used as sources of energy. For example, we know that various microbes produce different types of gases as their end products. One such gas is biogas. It is a mixture of gases produced by microbes and is used as a fuel. Similarly, some anaerobic bacteria which grow on cellulosic materials produce gases like methane, hydrogen gas and CO 2 . Thus, we can say that microbes can be used as a source of energy.

Q10. Microbes can be used to decrease the use of chemical fertilisers and pesticides. Explain how this can be accomplished.

Answer:

Generally, farmers use chemical fertilizers and pesticides in their fields. However, these chemical-based fertilizers and pesticides have deleterious effects on us. They tend to pollute the environment including soil and nearby water bodies. The fruits, vegetables and grains grown in fields in chemical fertilizers and pesticides, the chemicals get incorporated in them and they become toxic for animals and humans. Thus, farmers need to find more environmental friendly methods to control pests and fertilize the soil. Biocontrol agents and biofertilizers are being used now to control pests and fertilize the soil respectively.

Microbes as biocontrol agents:

These are microbes or other biological organisms that can be used to control pest and parasite populations in fields. For example, the Bt toxins of Bacillus thuringiensis are used to control lepidopteran insects. Trichoderma is free-living fungi that are very common in the root systems and control several plant pathogens. Baculoviruses are also pathogens that attack insects and other arthropods. The majority of baculoviruses used as biological control agents are in the genus Nucleopolyhedrovirus. These viruses are excellent candidates for species-specific, narrow spectrum insecticidal applications.

Microbes as biofertilizers:

Bio fertilisers are organisms that enrich the nutrient quality of the soil. The main sources include bacteria, fungi and cyanobacteria. The root nodule formed by Rhizobium bacteria on the root of leguminous plants increases the nitrogen level of soil, necessary for various metabolic processes. Azotobacter and Azospirillum are free-living bacteria that live in soil and fix atmospheric nitrogen into organic forms. Cyanobacteria such as Nostoc, Anabaena are autotrophic microbes found in aquatic and terrestrial environment that fix atmospheric nitrogen.

Q11. Three water samples namely river water, untreated sewage water and secondary effluent discharged from a sewage treatment plant were subjected to BOD test. The samples were labelled A, B and C; but thelaboratory attendant did not note which was which. The BOD values of the three samples A, B and C were recorded as 20mg/L, 8mg/L and 400mg/L, respectively. Which sample of the water is most polluted? Can you assign the correct label to each assuming the river water is relatively clean?

Answer:

BOD means biochemical oxygen demand. It refers to the amount of oxygen consumed if all organic matter in 1 ltr of water is oxidized by bacteria. BOD tests measure the rate of update of oxygen by microorganisms in the water sample. Greater the value of BOD more is the polluting potential. Out of the three samples mentioned above, secondary effluent has the highest BOD value, so it is most polluted. So, the correct labelling will be:

(a) Secondary effluent

(b) River water

(c) Untreated sewage water.

Microbes in Human Welfare Class 12 NCERT Solutions:

Q12. Find out the name of the microbes from which Cyclosporin A (an immunosuppressive drug) and Statins (blood cholesterol lowering agents) are obtained.

Answer:

Cyclosporin A – Trichoderma polysporum (fungus)

Statins – Monascus purpureus (yeast)

Microbes in Human Welfare Class 12 Questions and Answers:

Q13. Find out the role of microbes in the following

(a) Single cell protein (SCP)

Answer:

Microorganisms like bacteria, yeast etc can be cultured on a large scale in the fermenters. They can be treated in many ways, dried and used as a food source or animal feed. These microorganisms that can be used as potential sources of proteins for animals and humans are called single cell protein. SCP is rich in proteins and can be produced in laboratories.

The major advantage of SCP is as follows:

1. The production of SCP do not depend upon climatic factors,

2. The microorganism grows at a very fast rate and requires very less space

3. The cost of production of SCP is very less.

4. Microorganisms used as substrates are otherwise pollutants so it also reduces pollution .

Q13. Find out the role of microbes in the following

(b) Soil

Answer:

Microbes decompose complex organic debris into a dark amorphous substance called humus and degradation products which can be used as manure to increase the fertility of soil. The manure can loosen the soil and increases aeration in the soil. It contains many organic substances which are easily assimilated by plants. Some microbes are used for enriching soil fertility. Microorganisms like Azatobacter and Rhizobium can be used as nitrogen fertilisers. Thus, it can be said that microbes play an important role in improving the quality of the soil.

Class 12 Biology Chapter 10 NCERT Solutions

Q14. Arrange the following in the decreasing order (most important first) of their importance, for the welfare ofhuman society. Give reasons for your answer.

Biogas, Citric acid, Penicillin and Curd

Answer:

These can be arranged as Penicillin - Biogas- Curd- Citric acid.

Penicillin is an antibiotic which is used to cure many diseases like pneumonia. Thus it should be the most important.

Biogas serves as a source of clean fuel, so it is the second most important.

Curd comes next which is a nutritious milk product.

Citric acid is used in food processing industries. Thus, it is last in the list

Class 12 Biology Chapter 10 NCERT Solutions:

Q15. How do biofertilisers enrich the fertility of the soil?

Answer:

The term biofertilizer is used for microorganisms that bring nutrient enrichment and minimize the environmental hazards of chemical fertilizers. These biofertilizers increase the physical and chemical structure of soil like buffer capacity and water holding capacity of the soil. Biofertilizers can be introduced into seeds, roots or soil in order to mobilize the desired nutrient. Rhizobium is a biofertilizer, that is introduced in roots and it fixes nitrogen for the plants. Similarly, Cyanobacteria like Nostoc, Anabaena are also used for fixing nitrogen.

NCERT Solutions for Class 12 Biology Chapter 10 – Microbes in Human Welfare

The CBSE Syllabus for the 2022–23 academic year includes the NCERT Solutions for Class 12 Biology Chapter 10 Microbes in Human Welfare, which is organised under the unit - Biology in Human Welfare. The total number of marks allotted for this unit's chapters is close to 14. Students can greatly benefit from Chapter 10 Biology Class 12 and increase their confidence in their academic performance by reviewing with NCERT Solutions and practising with question papers and sample tests from prior years. Go through the each concepts from Microbes in Human Welfare Class 12 Solutions.

Class 12 Microbes in Human Welfare NCERT Solutions explains how Antibiotics like penicillin, produced by useful microbes, are used to kill disease-causing microbes. Antibiotics have played a major role in controlling infectious diseases like:

  1. Diphtheria
  2. Whooping cough and
  3. Pneumonia
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After going through Class 12 Biology Chapter 10 NCERT Solutions line by line, you will be able to answer all the questions by yourself also. If you have any confusion or you are unable to answer them by yourself, then Class 12 Microbes in Human Welfare NCERT Solutions will help you to answer.

So, try to attempt all the Ch 10 Biology Class 12 questions and answers mentioned in Microbes in Human Welfare NCERT, to clear your base. If you need help then, CBSE Class 12 Biology Chapter 10 question answer is there, you will get all the answers to the questions mentioned in the NCERT book. Biology Chapter 10 Class 12 will also help you to prepare for other competitive exams like NEET.

NCERT Solutions for Class 12 Biology Chapter 10 Microbes in Human Welfare

Important Topics and Subtopics in NCERT Solutions for Class 12 Biology Microbes in Human Welfare:

Section
Topic Name
10
Microbes in Human Welfare
10.1Microbes in Household Products
10.2Microbes in Industrial Products
10.3Microbes in Sewage Treatment
10.4Microbes in Production of Biogas
10.5Microbes as Biocontrol Agents
10.6Microbes as Biofertilisers
10.7Summary
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Important Subtopics in NCERT Solutions for Class 12 Biology Chapter 10 Microbes in Human Welfare

  • 10.2 - Microbes in Industrial Products
  • 10.2.1 - Fermented Beverages
  • 10.2.2 - Antibiotics
  • 10.2.3 - Chemicals, Enzymes, and other Bioactive Molecules
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Highlights of NCERT Solutions Class 12 Biology Chapter 10 – Microbes in Human Welfare

Class 12 Biology Chapter 10 NCERT Solutions highlights are given below:

  • The Microbes in Human Welfare Class 12 NCERT Solutions are written in the best possible way using simple language that makes solutions easier to read and understand
  • In the NCERT Class 12 Biology Chapter 10 PDF, points are used to frame answers to help understand quickly.
  • Solution content for Chapter 10 Biology Class 12 is derived from the textbook by the subject expert.
  • Solutions for Microbes in Human Welfare NCERT are as per the latest CBSE Syllabus and guidelines.
  • Microbes in Human Welfare Class 12 PDF links are readily available and easily accessible for free.
  • Important topics are listed in the Biology Chapter 10 Class 12.
  • Ch 10 Biology Class 12 is a great resource for information.

Class 12 Biology Chapter 10 NCERT Solutions

In CBSE NCERT Solutions for Class 12 Biology Chapter 10 Microbes in Human Welfare, you will see that certain dishes such as idli and dosa, are made from dough fermented by different kinds of microbes only. Bacteria and fungi are used to impart particular texture, taste, and flavor to the cheese. In NCERT Solutions for Microbes in Human Welfare Class 12 PDF, questions and solutions are related to microbes as microbes are used to produce industrial products like lactic acid, acetic acid, and alcohol, which are used in a variety of processes in the industry.

In Class 12 Biology Ch 10 question answer, you will get problem on different uses of microbes. For more than a hundred years, microbes are being used to treat sewage (wastewater) by the process of activated sludge formation and this helps in recycling of water in nature. Methanogens produce methane (biogas) while degrading plant waste. Biogas produced by microbes is used as a source of energy in rural areas as given in Class 12 microbes in human welfare NCERT solutions. Microbes can also be used to kill harmful pests, a process called as biocontrol. The biocontrol measures help us to avoid the heavy use of toxic pesticides for controlling pests.

NCERT Exemplar Class 12 Solutions

Also Check NCERT Books and NCERT Syllabus here:

NCERT Solutions for Class 12 Biology- Chapter wise

NCERT Solutions for Class 12- Subject wise


We hope that you will ace your examination with the help of NCERT Solutions for Class 12 Biology Chapter 10 Microbes in Human Welfare.

Frequently Asked Question (FAQs)

1. what are the Important topics of CBSE 12th assignment answers pdf for NCERT class 12 biology chapter 10 microbes in human welfare?

The Important topics of NCERT Solutions for Class 12 Biology Chapter 10 are:

   10.1 Microbes in Household Products   

   10.2 Microbes in Industrial Products   

   10.2.1 Fermented Beverages   

   10.2.2 Antibiotics   

   10.2.3 Chemicals, Enzymes, and other Bioactive Molecules   

   10.3 Microbes in Sewage Treatment   

   10.4 Microbes in Production of Biogas   

   10.5 Microbes as Biocontrol Agents   

   10.6 Microbes as Bio fertilisers 

2. what are the benefits of cbse 12th assignment answers pdf?

After going through CBSE 12th assignment answers pdf for class 12 biology chapter 10 microbes in human welfare line by line, you will be able to answer all the questions by yourself also. If you have any confusion or you are unable to answer them by yourself, then CBSE 12th assignment answers pdf will help you to answer.  

3. How to download microbes in human welfare class 12 pdf?

To download microbes in human welfare class 12 pdf, students can use the online webpage to pdf converter tools. To Score Well in the examination, follow the NCERT syllabus and exercise given in the NCERT Book. To practice more problems, students can refer to the NCERT exemplar  

4. How to solve the questions present in Chapter 10 of NCERT Solutions for Class 12 Biology faster?

To learn more about the key ideas covered in the NCERT textbook, Class 12 students should attempt the questions. Students should consult the Class 12 Biology NCERT Solutions if they have any questions about how to solve a particular problem because every single one is correctly addressed there. Students can easily understand how to solve problems because the solutions include step-by-step explanations.

5. What are the key features of NCERT Solutions for Class 12 Biology Chapter 10?

Below are some highlights of the NCERT Solutions for Class 12 Biology Chapter 10:

1. Highly qualified Biology experts have prepared the answers.

2. The solutions are correct and error-free and are based on the most recent CBSE Syllabus.

3. To assist students in performing well on the board exams, every crucial concept is clarified in layman's terms.

4. Using NCERT Solutions, students gain a thorough understanding of the key ideas.

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A block of mass 0.50 kg is moving with a speed of 2.00 ms-1 on a smooth surface. It strikes another mass of 1.00 kg and then they move together as a single body. The energy loss during the collision is

Option 1)

0.34\; J

Option 2)

0.16\; J

Option 3)

1.00\; J

Option 4)

0.67\; J

A person trying to lose weight by burning fat lifts a mass of 10 kg upto a height of 1 m 1000 times.  Assume that the potential energy lost each time he lowers the mass is dissipated.  How much fat will he use up considering the work done only when the weight is lifted up ?  Fat supplies 3.8×107 J of energy per kg which is converted to mechanical energy with a 20% efficiency rate.  Take g = 9.8 ms−2 :

Option 1)

2.45×10−3 kg

Option 2)

 6.45×10−3 kg

Option 3)

 9.89×10−3 kg

Option 4)

12.89×10−3 kg

 

An athlete in the olympic games covers a distance of 100 m in 10 s. His kinetic energy can be estimated to be in the range

Option 1)

2,000 \; J - 5,000\; J

Option 2)

200 \, \, J - 500 \, \, J

Option 3)

2\times 10^{5}J-3\times 10^{5}J

Option 4)

20,000 \, \, J - 50,000 \, \, J

A particle is projected at 600   to the horizontal with a kinetic energy K. The kinetic energy at the highest point

Option 1)

K/2\,

Option 2)

\; K\;

Option 3)

zero\;

Option 4)

K/4

In the reaction,

2Al_{(s)}+6HCL_{(aq)}\rightarrow 2Al^{3+}\, _{(aq)}+6Cl^{-}\, _{(aq)}+3H_{2(g)}

Option 1)

11.2\, L\, H_{2(g)}  at STP  is produced for every mole HCL_{(aq)}  consumed

Option 2)

6L\, HCl_{(aq)}  is consumed for ever 3L\, H_{2(g)}      produced

Option 3)

33.6 L\, H_{2(g)} is produced regardless of temperature and pressure for every mole Al that reacts

Option 4)

67.2\, L\, H_{2(g)} at STP is produced for every mole Al that reacts .

How many moles of magnesium phosphate, Mg_{3}(PO_{4})_{2} will contain 0.25 mole of oxygen atoms?

Option 1)

0.02

Option 2)

3.125 × 10-2

Option 3)

1.25 × 10-2

Option 4)

2.5 × 10-2

If we consider that 1/6, in place of 1/12, mass of carbon atom is taken to be the relative atomic mass unit, the mass of one mole of a substance will

Option 1)

decrease twice

Option 2)

increase two fold

Option 3)

remain unchanged

Option 4)

be a function of the molecular mass of the substance.

With increase of temperature, which of these changes?

Option 1)

Molality

Option 2)

Weight fraction of solute

Option 3)

Fraction of solute present in water

Option 4)

Mole fraction.

Number of atoms in 558.5 gram Fe (at. wt.of Fe = 55.85 g mol-1) is

Option 1)

twice that in 60 g carbon

Option 2)

6.023 × 1022

Option 3)

half that in 8 g He

Option 4)

558.5 × 6.023 × 1023

A pulley of radius 2 m is rotated about its axis by a force F = (20t - 5t2) newton (where t is measured in seconds) applied tangentially. If the moment of inertia of the pulley about its axis of rotation is 10 kg m2 , the number of rotations made by the pulley before its direction of motion if reversed, is

Option 1)

less than 3

Option 2)

more than 3 but less than 6

Option 3)

more than 6 but less than 9

Option 4)

more than 9

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