Microbes in Human Welfare MCQ

Correct Answer: C. Insects. While insects are small, they are not microscopic and belong to the animal kingdom.

Correct Answer: B. Deep-sea thermal vents. Microbes are known to exist in extreme environments, including very hot places like thermal vents.

Correct Answer: B. They are only visible with a microscope. This is the key characteristic that defines microbes.

Correct Answer: C. They are proteins that can cause infections. Prions are an example of such infectious agents.

Correct Answer: D. All of the above. Culturing microbes serves various purposes in research and industry.

Correct Answer: B. Lactobacillus acidophilus. This bacteria converts lactose in milk to lactic acid, causing it to curdle.

Correct Answer: B. Fermentation. Yeast ferments sugars in the dough, producing carbon dioxide that makes the bread rise.

Correct Answer: B. Toddy. This beverage is made by fermenting the sap of palm trees.

Correct Answer: C. Coagulating milk proteins. Microbes aid in the curdling process, which is essential for cheese production.

Correct Answer: C. Roquefort. This cheese is ripened with Penicillium roqueforti, giving it the blue veins.

Correct Answer: C. Fermentor. These vessels provide a controlled environment for large-scale microbial growth.

Correct Answer: C. Saccharomyces cerevisiae. This yeast is used for fermentation in the production of various alcoholic beverages.

Correct Answer: C. Penicillin. Its discovery was a major breakthrough in the fight against bacterial diseases.

Correct Answer: B. Alexander Fleming. He observed the antibacterial effect of the Penicillium mold.

Correct Answer: D. Dissolving blood clots. Streptokinase is used as a “clot buster” to treat heart attack patients.

Correct Answer: A. Streptococcus. This bacterium is the source of the enzyme streptokinase.

Correct Answer: C. Immunosuppressant for organ transplants. Cyclosporin A helps prevent organ rejection.

Correct Answer: A. Aspergillus niger. This fungus is widely used for industrial citric acid production.

Correct Answer: D. Statins. These drugs inhibit cholesterol synthesis.

Correct Answer: D. Monascus purpureus. This yeast is the source of statins.

Correct Answer: C. Human excreta. Sewage mainly consists of human waste along with other organic matter.

Correct Answer: D. All of the above. Untreated sewage poses significant health and environmental risks.

Correct Answer: C. To reduce the pollution potential of the wastewater. Sewage treatment aims to make the water safe for disposal.

Correct Answer: C. Physical removal of particles through filtration and sedimentation. This is the first step in sewage treatment.

Correct Answer: C. To promote the growth of aerobic microbes. These microbes help break down organic matter.

Correct Answer: B. The amount of organic matter in water. BOD indirectly measures the amount of organic matter by measuring the oxygen required for its decomposition.

Correct Answer: B. To reduce the pollution potential of the sewage. Lower BOD indicates lower organic pollution.

Correct Answer: B. Primary sludge. This is the sediment formed during the primary treatment.

Correct Answer: C. To further digest the activated sludge. Anaerobic bacteria break down the remaining organic matter in the sludge.

Correct Answer: C. Methane. This is the main component of biogas produced in the digesters.

Correct Answer: A. To serve as inoculum for further microbial growth. This helps maintain a healthy population of microbes in the aeration tank.

Correct Answer: A. It is discharged into natural water bodies. After secondary treatment, the water is considered safe for release.

Correct Answer: C. Ganga Action Plan and Yamuna Action Plan. These plans focus on building sewage treatment plants to reduce river pollution.

Correct Answer: A. Methane. Biogas is primarily composed of methane, making it a valuable fuel source.

Correct Answer: A. Methanogens. These bacteria produce methane during the anaerobic digestion of organic matter.

Correct Answer: D. All of the above. Methanogens thrive in anaerobic environments rich in organic matter.

Correct Answer: A. Biogas produced from cattle dung. “Gobar” refers to cattle dung, which is a common source of biogas.

Correct Answer: A. To collect and store the biogas produced. The cover rises as gas is produced.

Correct Answer: B. It is used as fertilizer. The slurry retains nutrients and is valuable for agriculture.

Correct Answer: C. Both A and B. These organizations have promoted biogas production in rural areas.

Correct Answer: B. Biocontrol. This method utilizes natural enemies of pests to keep their populations in check.

Correct Answer: D. All of the above. Biocontrol offers several advantages over conventional chemical methods.

Correct Answer: B. Ladybug. Ladybugs are natural predators of aphids and help control their populations.

Correct Answer: B. Bacillus thuringiensis. This bacterium produces toxins that are lethal to certain insects.

Correct Answer: B. It produces toxins that kill insect larvae. The toxins are activated in the insect’s gut, leading to its death.

Correct Answer: B. Bt-cotton. This genetically modified cotton variety expresses Bt toxins to deter insect pests.

Correct Answer: C. Trichoderma. This fungus exhibits antagonistic effects against various plant pathogens.

Correct Answer: C. Managing insect pests. Baculoviruses are highly specific pathogens that infect and kill insects.

Correct Answer: B. They have minimal impact on non-target organisms. Baculoviruses are known for their host specificity.

Correct Answer: B. A holistic approach that combines various pest control methods. IPM integrates different strategies for sustainable pest management.

Correct Answer: B. Organisms that enrich the nutrient quality of the soil. Biofertilizers are living organisms that improve soil health.

Correct Answer: D. Protozoa. While protozoa are microbes, they are not typically used as biofertilizers.

Correct Answer: A. Nitrogen fixation in the soil. Rhizobium forms symbiotic associations with leguminous plants and converts atmospheric nitrogen into usable forms.

Correct Answer: B. Azotobacter. This bacterium can fix nitrogen without forming a symbiotic relationship with plants.

Correct Answer: B. Mycorrhiza. This mutually beneficial relationship helps plants access nutrients more efficiently.

Correct Answer: D. All of the above. Mycorrhizae provide multiple benefits to plants.

Correct Answer: B. Cyanobacteria. These photosynthetic bacteria can fix nitrogen and add organic matter to the soil.

Correct Answer: A. Reduced environmental impact. Biofertilizers are a more sustainable alternative to chemical fertilizers.

Correct Answer: D. Depletion of the ozone layer. Microbes do not contribute to ozone depletion; in fact, some play a role in ozone formation.

Correct Answer: B. By degrading organic matter in sewage. Microbes play a crucial role in breaking down organic pollutants in wastewater.

Correct Answer: D. All of the above. The dough used for idli and dosa is fermented by bacteria, which produce carbon dioxide, giving it a puffed-up appearance. This is a staple in South Indian cuisine.

Correct Answer: B. Propionibacterium sharmanii. This bacterium produces a significant amount of carbon dioxide during the cheese-making process, resulting in the characteristic large holes in Swiss cheese.

Correct Answer: C. They are used to treat fungal infections only. This statement is incorrect. Antibiotics are primarily used to treat bacterial infections, not fungal ones.

Correct Answer: D. Both B and C. Streptokinase is used as a clot buster, and Cyclosporin A is an immunosuppressant. Neither of these directly lowers cholesterol levels.

Correct Answer: A. Acetobacter aceti. This bacterium is used for the industrial production of acetic acid, the main component of vinegar.

Correct Answer: C. It is safe to be discharged directly into natural water bodies. This statement is incorrect. Sewage is harmful due to the presence of pathogens and organic pollutants, and it requires treatment before disposal.

Correct Answer: C. Aeration. Aeration is a key process in secondary treatment, where it promotes the growth of aerobic microbes to break down organic matter.

Correct Answer: B. Activated sludge. This sediment is rich in aerobic microbes that have consumed a significant portion of the organic matter in the sewage.

Correct Answer: B. Nitrogen fixation. This process is crucial for making nitrogen available to plants, which are unable to use nitrogen directly from the atmosphere.

Correct Answer: B. Glomus. Many members of the genus Glomus form symbiotic associations with plant roots, known as mycorrhizae.

Correct Answer: A. Enhanced photosynthesis. While mycorrhizae provide numerous benefits, they do not directly enhance the process of photosynthesis.

Correct Answer: D. Lactobacillus. This is a lactic acid bacterium commonly found in dairy products and is not involved in nitrogen fixation or used as a biofertilizer in paddy fields.

Correct Answer: C. It cannot be used for cooking or lighting. This statement is incorrect. Biogas is commonly used as a fuel source for cooking and lighting, especially in rural areas.

Correct Answer: A. Aeration tank. Aeration tanks are used in sewage treatment plants to promote aerobic microbial growth, not in biogas plants.

Correct Answer: C. They contribute to environmental pollution. This statement is incorrect. Biofertilizers are a more environmentally friendly alternative to chemical fertilizers and help reduce pollution.

Correct Answer: D. None of the above. All the listed foods—curd, dosa, and bread—are produced using microbial fermentation processes.

Correct Answer: D. None of the above. Microbes are used in the industrial production of various products, including biogas, alcohol, and penicillin.

Correct Answer: A. They are present only in soil and water. This statement is incorrect. Microbes are ubiquitous and can be found in a wide range of environments, including air, inside our bodies, and even in extreme conditions.

Correct Answer: A. Production of oxygen. While some microbes in sewage treatment are aerobic, the primary goal is not oxygen production. The focus is on reducing BOD, forming activated sludge, and generating biogas.

Correct Answer: C. They have a negative impact on soil fertility. This statement is incorrect. Biofertilizers enhance soil fertility by providing essential nutrients and improving soil health.

Correct Answer: B. Fermentation of dough in bread making. Yeast is a key ingredient in bread making, where it ferments sugars to produce carbon dioxide, causing the dough to rise.

Correct Answer: D. All of the above. Microbes offer several advantages in industrial applications, including versatility, efficiency, and sustainability.

Correct Answer: A. They break down organic matter in the absence of oxygen. This anaerobic digestion process is essential for biogas production.

Correct Answer: D. All of the above. Biocontrol offers several environmental and economic advantages over chemical pest control.

Correct Answer: A. To provide essential nutrients to plants. Biofertilizers enhance soil fertility by supplying nutrients like nitrogen and phosphorus.

Correct Answer: C. Azotobacter. This bacterium is a free-living nitrogen fixer that improves soil fertility.

Correct Answer: A. Bioremediation. This process utilizes microbes to degrade or detoxify pollutants.

Correct Answer: D. All of the above. Microbes hold immense potential for various future applications in biotechnology and environmental science.

Correct Answer: D. All of the above. Sewage treatment is crucial for public health, environmental protection, and water conservation.

Correct Answer: D. All of the above. Microbes play a vital role in nutrient cycling, ensuring the sustainability of ecosystems.

Correct Answer: C. It is used as a biofertilizer. This statement is incorrect. Monascus purpureus is used to produce statins, which are cholesterol-lowering agents, not as a biofertilizer.

Correct Answer: A. They pollute the environment. This statement is incorrect. Biofertilizers are environmentally friendly and help reduce pollution caused by chemical fertilizers.

Correct Answer: C. They cannot fix atmospheric nitrogen. This statement is incorrect. Many cyanobacteria, such as Anabaena, Nostoc, and Oscillatoria, are known for their ability to fix atmospheric nitrogen.

Correct Answer: A. They cause a large number of diseases in human beings. While some microbes are pathogenic, many others are beneficial and contribute to human welfare in various ways.

Correct Answer: C. They improve soil fertility and promote sustainable agriculture. This statement is incorrect. While chemical fertilizers can increase crop yield in the short term, their overuse has negative consequences for the environment and long-term soil health.

Correct Answer: C. They are effective biocontrol agents against several plant pathogens. This statement is incorrect. Baculoviruses are primarily used for insect control, not for controlling plant pathogens.

Correct Answer: C. It is used as an immunosuppressive agent in organ-transplant patients. This statement is incorrect. Cyclosporin A, produced by the fungus Trichoderma polysporum, is used as an immunosuppressive agent, not Trichoderma itself.

Correct Answer: B. It is a direct measure of the organic matter present in the water. This statement is incorrect. BOD is an indirect measure of organic matter, as it assesses the oxygen required for microbial decomposition of that organic matter.

Correct Answer: B. It requires a constant supply of oxygen for optimal functioning. This statement is incorrect. Biogas production relies on anaerobic digestion, meaning it occurs in the absence of oxygen.

Correct Answer: D. They are responsible for the depletion of the ozone layer. This statement is incorrect. Microbes are not responsible for ozone layer depletion. In fact, some microbes play a role in ozone formation.