NCERT Solutions for Class 12 Biology Chapter 8

As per the revised curriculum of CBSE Syllabus 2023-24, this chapter, previously known as Chapter 10, has now been renumbered as Chapter 8. Stay updated with the latest changes in the curriculum.

Microbes in Human Welfare Class 12 NCERT Solution is all about microbes and their usage in daily life. These NCERT Solutions are prepared by our Top Biology Experts in order to take care of all Important Topics that might be asked in the upcoming examination 2023. So, Students can also refer to these solutions for their final Examination preparation.

This Class 12 Biology Chapter 8 Microbes in Human Welfare NCERT Solutions are carefully developed using easy-to-understand language while adhering to the guidelines for solving NCERT Solutions for Class 12. Working through these solutions can be highly beneficial for students in their board exams, as well as in preparing for future competitive Exams.

Microbes in Human Welfare Class 12 Questions and Answers

NCERT solution of Microbes In Human Welfare of Class 12 explains the role of microbes in daily life, and how they are beneficial to humans. Microbes are small living organism that is not visible to the naked eye. Revise the basic concepts of Microbes in Human Welfare for quick revision and class notes.

Q1: Bacteria cannot be seen with the naked eye, 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 under a microscope, which sample would you carry and why?

Answer:

I would carry a sample of either soil or curd. Both the samples can be used to study microbes. In curd, a little drop contains a number of lactic acid bacteria (LAB) or Lactobacillus are present, which possess different shapes and sizes. These bacteria release acids that coagulate and digest milk proteins. Soil is the natural habitat of microorganisms that can be easily observed under the microscope.

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

Answer:

Many examples show that microbes release gases during their metabolism. Here are some examples: 

• Methanobacterium is found in anaerobic sludge and produces methane, carbon dioxide, and hydrogen. 
• Swiss cheese has a special flavor and large holes. These large holes are caused by the production of carbon dioxide released by the bacterium Propionibacterium Sharmanii.

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

Answer:

Milk, Curd, and Cheese are some coagulated products in which lactic acid bacteria (LAB) are present which convert lactose sugar into lactic acid. They increase the nutritional quality of the curd by increasing the vitamin B12 quantity in them. In our gut, LAB checks some disease-causing microorganisms. Therefore, the consumption of some probiotics is recommended as they contain LAB.

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

Answer:

Traditional Indian Foods	Microbes used
Dosa, vada, Upma, and idli	Fermented by bacteria
Bread	Saccharomyces cerevisiae (yeast)
Jalebi	Saccharomyces cerevisiae (yeast)

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

Answer:

Antibiotics are chemicals that are prepared by microorganisms and used to kill other microorganisms which cause diseases such as whooping cough, TB, and leprosy. Streptomycin, tetracycline, and penicillin are some common antibiotics. These are obtained from bacteria and fungi. Antibiotics are designed to destroy bacteria by weakening their cell wall.

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

Answer:

Species of Fungus	Antibiotics
Penicillin notatum	penicillin
Cephalosporium sp.	cephalosporin

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

Answer:

The municipal wastewater that is contaminated with feces or urine is sewage. It has some quantity of organic matter and microbes too, which are pathogenic and may cause diseases. Sewage is wastewater released from household and industrial applications. It is harmful to us in a number of ways. It destroys flora and fauna in water. Many life-threatening diseases can be spread by contaminated water.

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

Answer:

Primary sewage treatment	Secondary sewage treatment
It is a mechanical process that involves the separation of small and large solid substances	It is a biological process that involves the action of microbes
It is less complicated	It is comparatively much complicated

Q9: Do you think microbes can also be used as a source of energy? If yes, how?

Answer:

Yes, microbes can also be used as an energy source. The microbes in the activated sludge are treated anaerobically in the biogas plant to produce biogas, which is a source of energy. Microbes can be used to make SCP (single-cell protein).

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

Answer:

Microbes can be used to reduce the use of chemical fertilizers and pesticides. It’s a profitable practice. This can be done with organic fertilizers. The main sources of organic fertilizers are bacteria, fungi, and cyanobacteria, which provide plants with sufficient nutrients. The use of legumes with Rhizobium bacteria enables the plant to fix atmospheric nitrogen in an accessible form. Some example of microbes are:

• Legumes plant and Rhizobium
• Using Sulfux fixing bacteria
• Using hydrogen fixing bacterium

Q11: Three water samples namely river water, untreated sewage water, and secondary effluent discharged from a sewage treatment plant were subjected to the BOD test. The samples were labeled A, B, and C; but the laboratory attendant did not note which was which. The BOD values of the three samples A, B, and C were recorded as 20 mg/L, and 8 mg/Land 400 mg/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:

Sample A (BOD 20 mg/l) is secondary wastewater discharged from a sewage treatment plant. Sample B (BOD 8 mg/L) is river water. Sample C (BOD 400 mg/L) is untreated wastewater. The BOD is a measure of the organic matter present in a body of water. The higher the BOD, the more polluted the water is.

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

Answer:

Name of the biomolecule	Name of the microbes
Cyclosporin A (an immunosuppressive drug)	Fungus- Trichoderma polysporum
Statins (blood cholesterol-lowering agents)	Yeast- Monascus purpureus

Q13: Find out the role of microbes in the following and discuss it with your teacher.

a) Single-cell protein (SCP)

b) Soil

Answer:

• Single Cell Protein (SCP): These are the beneficial microbial cells that are used as a substitute for protein by many astronauts and athletes. The good sources are bacteria, yeast, and algae. The fat content is low in SCP.
• Soil:  Microbes present in the soil are used as biofertilizers and biopesticides. They increase soil fertility. Some bacteria have the ability to fix atmospheric nitrogen for plants.

Q14: Arrange the following in the decreasing order (most important first) of their importance, for the welfare of human society. Give reasons for your answer.Biogas, Citric acid, Penicillin and Curd

Answer:

Biogas>Penicillin >Curd>Citric acid

Biogas is the most important because it reduces pollution and can be used as a fuel. Penicillin is an antibiotic that is used in the treatment of many diseases. Curd is a dairy product used in the household. Citric acid is a chemical.

Q15: How do biofertilizers enrich the fertility of the soil?

Answer:

Bio-fertilizers are living organisms that help in increasing soil fertility. This involves the use of some beneficial microbes. Some species of bacteria and cyanobacteria have the ability to fix atmospheric nitrogen. Rhizobium is a symbiotic bacteria that is found in the root nodules of leguminous plants.

Key Features of NCERT Solutions Class 12 Biology Chapter 8 Microbes in Human Welfare

• They enhance the conceptual knowledge of the students.
• Clear and Comprehensible Content.
• Aid in Competitive Exam Preparation.
• The answers are provided by Top subject experts.
• Readily available and easily accessible.

FAQs on Microbes in Human Welfare Class 12 NCERT Solution

Q1: What is the name of chapter 8 of ncert class 12 Biology?

Answer:

Class 12 Biology Chapter 8 name is Microbes in Human Welfare which explains explains the role of microbes in daily life

Q2: Where can I find NCERT solutions for Class 12 Biology Chapter 8?

Answer:

NCERT solutions for Class 12 Biology Chapter 8 can be found on various online platforms such as the official NCERT website, GeeksForGeeks, and more.

Q3: Why are NCERT Solutions for Class 12 Biology Chapter 8 beneficial for the students??

Answer:

The benefits of using the NCERT Solutions for Class 12 Biology Chapter 8 are:

1. Completely solved answers for all the questions present in the NCERT textbook are available in PDF format.
2. Simple and easy-to-understand language is used to make learning fun for the students.
3. Top Subject matter experts prepare the solutions after conducting vast research on each concept.
4. The solutions not only help students with their board exam preparation but also for various competitive exams like JEE, NEET, etc.