NCERT solutions for class 12 biology chapter 10 microbes in human welfare: Microbes are a very important component of life on earth. Solutions for NCERT class 12 biology chapter 10 microbes in human welfare will tell you a very interesting thing that all microbes are not pathogenic. Even many microbes are very useful to human beings. We use microbes and microbially 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 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 class 12 biology chapter 10 microbes in human welfare, 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. If you are looking for the answers of any other class from 6-12 then NCERT solutions are there for you as it's the easiest way to get all the solutions of NCERT.
Important topics of solutions for NCERT class 12 biology chapter 10 microbes in human welfare:
10.1 Microbes in Household Products
10.2 Microbes in Industrial Products
10.2.1 Fermented Beverages
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
Antibiotics like penicillins produced by useful microbes are used to kill disease-causing harmful microbes. Antibiotics have played a major role in controlling infectious diseases like:
- Whooping cough and
NCERT solutions for class 12 biology chapter 10 microbes in human welfare, you will get answers 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. 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 solutions for class 12 biology chapter 10 microbes in human welfare: Solved Exercise Questions:
Q5. In which way have microbes played a major role in controlling diseases caused by harmful bacteria?
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.
Q7. What is sewage? In which way can sewage be harmful to us?
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.
Q8. What is the key difference between primary and secondary sewage treatment?
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?
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.
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.
Q13. Find out the role of microbes in the following
(a) Single cell protein (SCP)
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
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.
Q15. How do biofertilisers enrich the fertility of the soil?
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.
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