Yes, Microbes in Human Welfare is included in the NEET syllabus under Class 12 Biology. It is an important chapter covering topics like antibiotics, fermentation, biogas production, and sewage treatment. Many NEET questions are asked from this chapter.
NCERT Solutions for Class 12 Biology Chapter 8 Microbes in Human Welfare
The NCERT Solutions for Class 12 Biology Chapter 8 Microbes in Human Welfare explore the diverse world of microorganisms. Microbes are found everywhere, including air, water, and soil, and play an important role in various biological processes. These solutions focus on the beneficial aspects of microbes in the field of agriculture, medicine, and environmental conservation. The NCERT Solutions are prepared by the subject experts, which makes the learning interesting and enjoyable.
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- Download Microbes in Human Welfare Class 12 Questions and Answers PDF
- Get Class 12 Biology Chapter 8 Microbes in Human Welfare Question Answer
- Approach to Solve Microbes in Human Welfare Class 12 Question Answer
- Main Topics of Class 12 Biology Chapter 8 Microbes in Human Welfare
- Important Questions from Class 12 Biology Chapter 8 Microbes in Human Welfare
- What Students Learn from Microbes in Human Welfare NCERT Solutions
- Why Class 12 Biology Chapter 8 Microbes in Human Welfare NCERT Solutions are Important?
- What Extra Should Students Study Beyond the NCERT for NEET?
- NCERT Solutions for Class 12 Biology- Chapter-wise
The Microbes in Human Welfare Class 12 question answer highlights the important topics like fermentation, sewage treatment, and the industrial production of enzymes. Questions from these concepts are frequently asked in the board exams and in medical entrance exams like NEET. Students can also download the PDF of the solutions to make the study more organised and systematic. Doing regular practice with the NCERT Solutions Class 12 Biology boosts confidence and improves problem-solving skills.
Download Microbes in Human Welfare Class 12 Questions and Answers PDF
Students can download the PDF of the Microbes in Human Welfare chapter from the link given below. The Microbes in Human Welfare Class 12 Questions and Answers PDF can be used offline for revision and to score well in exams.
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NCERT Exemplar For Class 12 Biology: Microbes in Human Welfare
Get Class 12 Biology Chapter 8 Microbes in Human Welfare Question Answer
Given below are the solved exercise questions of the Microbes in Human Welfare chapter. Practicing the Class 12 Biology Chapter 8 Microbes in Human Welfare question answers that are prepared according to the latest NCERT curriculum will help students answer the questions effectively.
Answer:
To demonstrate the presence of microbes with the help of a microscope, the best sample we can carry is curd. Curd contains lactic acid bacteria (LAB), such as Lactobacillus, and is safe. A small portion of curd contains millions of bacteria, which can easily be observed under the microscope.
Q2. Give examples to prove that microbes release gases during metabolism.
Answer:
There are many examples where we find that microbes release gases during metabolism:
The dough that is used for making foods such as dosa and idlis is fermented by bacteria. The puffed appearance of dough is due to the production of CO2 gas.
The dough that is used for making bread is fermented by using baker’s yeast (Saccharomyces cerevisiae).
The large holes in Swiss cheese are due to the production of a large amount of CO2 by the bacteria.
Q3. In which food would you find lactic acid bacteria? Mention some of their useful applications.
Answer:
Lactic acid bacteria grow in milk and convert it to curd. Besides this, there are other applications of lactic acid bacteria given below:
LAB improves nutritional quality (e.g., some B-vitamins, better digestibility) and acts as probiotics that check pathogenic microbes.
In our stomachs, too, the LAB plays a very beneficial role in checking disease-causing microbes.
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Traditional Indian foods made of wheat, rice, and Bengal gram are:-
Wheat- Bread, Bathura, and cake are prepared from wheat.
Rice - Dosa and idlis involve the use of microbes.
Bengal gram- Dhokla and khandvi are made from the Bengal gram
Q5. In which way have microbes played a major role in controlling diseases caused by harmful bacteria?
Answer:
Microorganisms have several characteristics that make them ideal organisms for the production of various products, including medicines, vaccines, and antibiotics that help in controlling diseases caused by harmful bacteria, which are given below:
Many medicines like Ergot, Cyclosporin A, and Statins are produced from the fungus and bacteria, which are used to induce uterine contractions, immunosuppressive agents, and blood cholesterol-lowering agents, respectively.
Penicillin, Cephalosporins, Streptomycin, Erythromycin, etc. Antibiotics are prepared from microbes for the treatment of diseases like pneumonia, cough, diphtheria, and leprosy.
Inactivated strains of microbes are used for producing vaccines.
Q6. Name any two species of fungus that are used in the production of antibiotics.
Answer:
Microorganisms possess several characteristics and are used in various fields, one of which is the important field where microbes are used in the production of antibiotics. Two species of fungus which are used in the production of antibiotics are:-
1) Penicillin - It's the first antibiotic to be discovered from the fungus Penicillium chrysogenum.
2) Cephalosporins - These are derived from the fungus source Acremonium, used as antibiotics that are effective against a wide range of bacterial infections.
Q7. What is sewage? In which way can sewage be harmful to us?
Answer:
Large quantities of wastewater are generated every day in cities. A major component of this wastewater is human excreta. This municipal wastewater is called sewage. It contains a large amount of organic matter and microbes.
Hence, proper sewage disposal is of prime importance; otherwise, untreated sewage, if disposed of in water bodies, results in waterborne diseases such as cholera and typhoid, which also cause depletion of dissolved oxygen in the water.
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 involves the physical removal of particles, large and small. | In this process, wastewater is poured into large tanks and useful aerobic microbes are allowed to grow. |
It can be done through sedimentation and filtration. | Microbes consume a large part of the organic matter and thus reduce its BOD. |
Q9. Do you think microbes can also be used as a source of energy? If yes, how?
Answer:
Several microbes have been found helpful in solving energy crises. Synthetic fuels are produced by the activity of microbes, including ethanol, methane, hydrogen, and hydrocarbons.
Gasohol- Gasohol is a mixture of 90% gasoline and 10% alcohol and is used in several countries to combat the energy shortage.
Production of Biogas- Biogas is a mixture of gases containing mainly methane produced by microbial activity. Livestock waste is used for the generation of biogas through microbial fermentation.
Hydrogen is a valuable fuel; several algae have the capability of producing hydrogen from water in sunlight.
Answer:
Chemical fertilizers and pesticides are made up of a few minerals, thus making the soil toxic and also exploiting its nutrients. To overcome these problems, the use of biofertilizers is being encouraged. Biofertilizers are organisms that enrich the nutrient quality of the soil. They promote growth by increasing the supply or availability of primary nutrients to the plant. They mostly include nitrogen-fixing microorganisms. Some of them are given below:
Legume-Rhizobium symbiosis- Certain nitrogen-fixing bacteria, for example, rhizobium, live in symbiosis where the legume provides carbohydrates to the bacteria. Rhizobium not only increases the production of crops but also leaves a fair amount of nitrogen in the soil, which benefits the crop.
Another example of this type of symbiosis is the Azolla-Anabaena symbiosis. Apart from them, Azotobacter and Azospirillum are free-living bacteria that fix nitrogen and make it available for crop plants.
Answer:
Biological oxygen demand (BOD) is a measure of the organic matter present in the water. The greater the BOD of wastewater, the more its polluting potential.
Label | BOD Value | Sample |
A | 20 mg/L | Secondary effluent discharge from a sewage treatment plant |
B | 8 mg/L | River Water |
C | 400 mg/L | Untreated Sewage water |
Answer:
Cyclosporin A is produced by the fungus Trichoderma polysporum, which is an immunosuppressive drug, and statins from the yeast Monascus purpureus, which are blood cholesterol-lowering agents.
Q13. Find out the role of microbes in the following
Answer:
Single-cell protein
SCP is a protein-rich biomass produced from microbes. It is used as a food supplement for both humans and animals.
Microbes like algae, bacteria, fungi, and yeast are used.
These microbes grow fast and contain a high amount of protein.
It can be grown on waste, so it also helps in waste management.
Does not depend on the climate, so production is easy and cheap.
Used in animal feed and also as a protein source for people
Q13. Find out the role of microbes in the following
b) Soil
Answer:
Soil
The microbes present in the soil increase the fertility of the soil by decomposing organic matter.
The bacteria Rhizobium live symbiotically in the nodules of the roots of leguminous plants, fixing atmospheric nitrogen into organic forms, which are used by the plant as a nutrient.
Similarly, some free-living bacteria in the soil, like Azospirillum and Azotobacter, fix atmospheric nitrogen, thus enriching the nitrogen content of the soil.
Biogas, Citric acid, Penicillin, and Curd
Answer:
Penicillin: Penicillin is the first antibiotic to be discovered, and it is an effective antibiotic to treat deadly diseases
Biogas: a mixture of gases (mainly containing methane) produced by the microbial activity on excreta (dung) of cattle, an eco-friendly source of energy, particularly in rural areas.
Curd: a portion of nutritious and easily digestible food for all age groups obtained from milk by the action of lactic acid bacteria (LAB).
Citric acid: It is produced industrially by microbial fermentation (Aspergillus niger).
Q15. How do biofertilizers enrich the fertility of the soil?
Answer:
Biofertilizers are organisms that enhance the nutrient quality of the soil. The main sources of biofertilizers are bacteria, fungi, and cyanobacteria.
Rhizobia bacteria live in a symbiotic association on the roots of leguminous plants. These bacteria fix atmospheric nitrogen into organic forms, which are used by the plant as a nutrient.
Other bacteria like Azospirillum and Azotobacter can also fix atmospheric nitrogen while free-living in the soil, thus enriching the nitrogen content of the soil and improving its quality.
Cyanobacteria (e.g., Anabaena, Nostoc, etc.) can also fix atmospheric nitrogen. In paddy fields, cyanobacteria add organic matter to the soil and increase its fertility.
NCERT Solutions for Class 12- Subject-wise
Approach to Solve Microbes in Human Welfare Class 12 Question Answer
Microbes play an important role in human welfare by contributing to food production, medicine, agriculture, etc. Understanding their uses helps in solving questions related to this topic.
Recognize how microbes are used in household products, industries, agriculture, and sewage treatment. Students can use the Class 12 Biology Chapter 8 Microbes in Human Welfare question answer to understand clearly.
Recall microbes such as Lactobacillus for curd, yeast for bread, and Rhizobium for nitrogen fixation.
Linked microbes with their uses, such as biofertilizers, biocontrol agents, and the synthesis of antibiotics.
Use simple definitions for terms such as biofertilizers, biogas, and single-cell protein. These are well-explained in the Class 12 Biology Microbes in Human Welfare question answer.
- Learn from the solved exercises given in the NCERT Solutions for Class 12 to understand the question pattern.
Also, check the NCERT Books and the NCERT Syllabus here:
Main Topics of Class 12 Biology Chapter 8 Microbes in Human Welfare
Microbes play an important role in improving human life by contributing to food production, medicine, agriculture, and environmental management. Class 12 Biology Chapter 8 Microbes in Human Welfare NCERT Solutions explains all the important topics which are included in the NCERT books.
Microbes in Household Products
Microbes in Industrial Products
Production of Antibiotics
Production of Organic Acids, Enzymes, and Alcohol
Microbes in Sewage Treatment
Primary and Secondary Sewage Treatment
Microbes as Biofertilisers
Role of Microbes in Organic Farming
Microbes as Biocontrol Agents
CBSE Class 12th Syllabus: Subjects & Chapters
Select your preferred subject to view the chapters
Important Questions from Class 12 Biology Chapter 8 Microbes in Human Welfare
Microorganisms are tiny organisms that are present everywhere. Given below are the important questions from this chapter, along with the answers. To gain clarity, students should practice more questions given in the NCERT Solutions for Class 12 Biology Chapter 8 Microbes in Human Welfare.
Question 1: Which of the following microbes is used for the commercial production of citric acid?
a) Lactobacillus
b) Aspergillus niger
c) Penicillium notatum
d) Rhizobium
Answer: The correct answer is option (b) Aspergillus niger
Explanation:
Aspergillus niger is a fungus widely used in industry to produce citric acid through fermentation. It efficiently converts sugars into citric acid under controlled conditions. This citric acid is then used in food, beverages, pharmaceuticals, and cleaning products due to its preservative and flavoring properties.
Question 2: Activated sludge should have the ability to settle quickly so that it can:
a) Be rapidly pumped back from the sedimentation tank to the aeration tank.
b) Absorb pathogenic bacteria present in wastewater while sinking to the bottom of the settling tank
c) Be discarded and anaerobically digested.
d) Absorb colloidal organic matter.
Answer: The correct answer is option (c) Be discarded and anaerobically digested.
Explanation:
- For activated sludge to be isolated from treated water, it must settle rapidly.
- By doing this, extra sludge can be disposed of and sent for anaerobic digestion.
- It is broken down by bacteria during digestion to produce biogas.
- This recycles energy and lessens waste.
Question 3: Methanogens do not produce:
a) Oxygen
b) Methane
c) Hydrogen sulfide
d) Carbon dioxide
Answer: The correct answer is option (a) Oxygen
Explanation:
Yes, methanogens are a group of anaerobic microorganisms that produce methane as a byproduct of their metabolic process. During the breakdown of organic matter, methanogens primarily convert carbon compounds into methane (CH₄), but they also produce other gases, including carbon dioxide (CO2) and hydrogen sulfide (H₂S).
Question 4: The primary treatment of wastewater involves the removal of:
a) dissolved impurities
b) stable particles
c) toxic substances
d) harmful bacteria
Answer: The correct answer is option (b) stable particles
Explanation:
Dissolved impurities, toxic substances, and harmful bacteria are usually removed during the later parts of purification treatments for water or drinking water. The term "stable particles" indicates that what is left after purification does not have an inherent ability to be harmful to health or the environment. If the use of water or the solution is to be made safe to utilize, that can result in an effective purification method by maintaining safety and quality.
Question 5: Big holes in Swiss cheese are made by a:
a) a machine
b) a bacterium that produces methane gas
c) a bacterium producing a large amount of carbon dioxide
d) a fungus that releases a lot of gases during its metabolic activities
Answer: The correct answer is option (c) a bacterium producing a large amount of carbon dioxide
Explanation:
The bacterium Propionibacterium sharmanii plays a key role in the production of Swiss cheese by fermenting lactic acid into carbon dioxide (CO₂) and propionic acid. The release of a large amount of CO₂ during this process creates the characteristic big holes or "eyes" in Swiss cheese. The propionic acid also contributes to the unique flavor of the cheese.
Question 6: The residue left after methane production from cattle dung is:
a) burnt
b) buried in landfills
c) used as manure
d) used in civil construction
Answer: The correct answer is option (c) used as manure
Explanation:
After methane (biogas) production from cattle dung, the leftover material is called slurry. This residue is rich in nutrients like nitrogen and organic matter, making it very useful as a natural manure. Therefore, it is commonly used in agriculture to improve soil fertility.
Question 7: The free-living fungus Trichoderma can be used for:
a) Killing insects
b) Biological control of plant diseases
c) Controlling butterfly caterpillars
d) Producing antibiotics
Answer: The correct answer is option (b) Biological control of plant diseases
Explanation:
Trichoderma is employed to mitigate the negative impacts of plant pathogens via growth and activity inhibition. It operates through the following key mechanisms:
a. Mycoparasitism: Direct parasitic interaction with harmful fungi.
b. Antibiosis: Production of antibiotics and other substances that obstruct pathogenic development.
c. Competition: Trichoderma outcompetes pathogens for essential resources and space.
NCERT Exemplar Class 12 Solutions
What Students Learn from Microbes in Human Welfare NCERT Solutions
This chapter explains how different microorganisms play a vital role in our daily lives and environment.
Students learn how microbes are used in household products like curd, cheese, and fermented foods.
Through the Microbes in Human Welfare Class 12 question answer, they understand the role of microorganisms in the industrial production of beverages and antibiotics.
The chapter helps them explore how sewage treatment plants use microbes to purify wastewater.
With the help of the Class 12 Biology Microbes in Human Welfare question answer, learners study how microbes act as biocontrol agents and biofertilizers in sustainable agriculture.
Learners also gain knowledge about biogas production and the contribution of microbes in generating renewable sources of energy.
Why Class 12 Biology Chapter 8 Microbes in Human Welfare NCERT Solutions are Important?
Microbes in Human Welfare is an important chapter as it allows students to understand the benefits of microorganisms in different fields, such as in producing medicines, agriculture, waste management, etc.
- Class 12 Biology Chapter 8 Microbes in Human Welfare NCERT Solutions clearly explain the industrial use of microbes in producing alcohol, antibiotics, and enzymes.
- Students also learn about the use of microbes in sewage treatment and biogas production by using the solutions.
- Microbes play an important role in food production, such as curd, cheese, and bread formation, which is explained in detail in the solutions.
- Topics like biofertilizers and biocontrol agents are described, which are frequently asked in the NEET or board exams.
What Extra Should Students Study Beyond the NCERT for NEET?
Here is a table for all the topics students study beyond the NCERT for the NEET exam. Along with this, to score well, students can refer to the NCERT Solutions for Class 12 Biology Chapter 8 Microbes in Human Welfare.
Topics | NCERT | NEET |
✅ | ✅ | |
✅ | ✅ | |
✅ | ✅ | |
✅ | ✅ | |
✅ | ✅ | |
✅ | ✅ | |
✅ | ✅ | |
✅ | ✅ |
NCERT Solutions for Class 12 Biology- Chapter-wise
Here is the complete chapter-wise table provided for easy access. Students can use these solutions to score well in their exams and boosts confidence.
Frequently Asked Questions (FAQs)
Q: Are microbes in human welfare in the NEET syllabus?
A:
Q: What is sewage class 12 NCERT solution?
A:
Sewage is wastewater released from homes, hospitals, offices, and industries. It contains human excreta, food waste, detergents, and harmful microbes. Sewage is treated in sewage treatment plants to remove pollutants before releasing it into water bodies.
Q: What are the 4 methods of sewage?
A:
In Class 12 Biology (Microbes in Human Welfare), sewage treatment is mainly done in 4 major steps/methods:
Primary treatment – physical removal of large particles by filtration and sedimentation.
Secondary treatment (biological treatment) – microbes break down organic matter (activated sludge process).
Anaerobic digestion – anaerobic bacteria digest sludge and produce biogas.
Disinfection – treated water is disinfected (chlorination/ozonation) before release.
Q: What is the role of microbes in vaccinations?
A:
Microbes play an important role in vaccination as vaccines are prepared using weakened (attenuated) or killed microbes, or their antigens. These stimulate the immune system to produce antibodies without causing the disease. This helps the body develop immunity and protect against future infections.
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Popular CBSE Class 12th Questions
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
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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
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A particle is projected at 600 to the horizontal with a kinetic energy . The kinetic energy at the highest point
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In the reaction,
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How many moles of magnesium phosphate, will contain 0.25 mole of oxygen atoms?
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0.02 |
Option 2)
3.125 × 10-2 |
| Option 3)
1.25 × 10-2 |
Option 4)
2.5 × 10-2 |
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