Practice Questions
Examine the use of microbes in the commercial production of organic acids. Name two different acids, the specific microbe used to produce each, and one industrial application.
Define biofertilisers.
List three examples of organic acids produced by microbes and name the respective microbe for each.
Apply your knowledge of microbial metabolism to explain why the dough used for making foods like dosa and idli has a puffed-up appearance after fermentation. Identify the key gas produced and the metabolic process responsible.
Name the bacterium responsible for the large holes in Swiss cheese and the gas it produces.
Identify the yeast species used for both bread-making and fermenting beverages.
Critique the practice of discharging untreated sewage into rivers, based on its effect on Biochemical Oxygen Demand (BOD).
Name the group of bacteria responsible for producing biogas and give one common example.
Evaluate the role of Lactic Acid Bacteria (LAB) in improving the nutritional quality of curd compared to milk.
Examine the specific role of the bacterium Propionibacterium sharmanii in the production of Swiss cheese. What characteristic feature does this microbe impart to the final product?
Propose a reason why are considered excellent candidates for integrated pest management (IPM) programs.
A patient suffering from a heart attack is administered Streptokinase. Justify the use of this bioactive molecule in this medical emergency.
Explain the key difference between alcoholic beverages produced with and without distillation, and provide one example for each category.
Describe the role of microbes in a typical biogas plant. Explain the plant's basic structure and the utilization of its products.
Summarize the key events in the discovery of Penicillin, including the scientists involved and the microbial source.
A farmer wants to reduce the use of chemical pesticides for controlling butterfly caterpillars on his brassica crops. Demonstrate how the application of Bacillus thuringiensis (Bt) can serve as an effective biocontrol agent in this scenario.
Apply the definition of an antibiotic to explain the dual meaning of the term: 'against life' in the context of pathogens but 'pro-life' in the context of humans.
Compare and contrast the industrial production of wine and whisky. Focus on the role of Saccharomyces cerevisiae and the key processing step that differentiates the two beverages.
Examine the biochemical function of statins, which are produced by the yeast Monascus purpureus, and explain how they benefit human health.
Compare the roles of free-living nitrogen-fixing bacteria like Azotobacter and symbiotic nitrogen-fixing bacteria like Rhizobium in their function as biofertilisers.
Justify why wine and beer production does not require distillation, unlike whisky and rum.
Define Biochemical Oxygen Demand (BOD).
Compare the metabolic roles of Lactobacillus in curd formation and Saccharomyces cerevisiae in bread making, focusing on the primary products that cause the characteristic changes in milk and dough.
Analyze the process of secondary sewage treatment. Explain how microbial activity reduces the Biochemical Oxygen Demand (BOD) and describe the fate of the microbial 'flocs' after the aeration stage.
Demonstrate how methanogens, such as Methanobacterium, are utilized in the production of biogas and simultaneously play a crucial role in the nutrition of cattle.
Analyze the symbiotic relationship in a mycorrhiza, specifically one formed by a fungus from the genus Glomus. Explain the benefits that both the plant and the fungus derive from this association.
Analyze the story of Alexander Fleming's discovery of penicillin. Explain the chance observation, the microbes involved, and how this event demonstrates the principle of antibiosis.
Propose a plan for a small-scale, eco-friendly waste management system for a rural household that integrates biogas production and the use of biofertilisers.
Design a public awareness campaign to promote the use of biofertilisers over chemical fertilisers among farmers in your region. Your design should include the key message, target audience, and proposed methods of dissemination.
Critique the conventional farming practice of using chemical pesticides and justify the switch to biocontrol agents like and .
Define antibiotics and explain their meaning in the context of human welfare.
Formulate an argument to convince a community to install a biogas plant, highlighting its dual benefits in energy production and waste management.
A food processing company wants to sell bottled fruit juices. Evaluate the necessity of using enzymes like pectinases and proteases in their production process compared to home-made juices.
Explain the role of Lactic Acid Bacteria (LAB) in the production of curd from milk.
Explain how Bacillus thuringiensis (Bt) acts as a biocontrol agent against butterfly caterpillars.
Recall the bioactive molecule produced by the fungus Trichoderma polysporum and state its primary use.
Design an experiment to demonstrate that the puffed-up appearance of dough is due to microbial fermentation and the production of gas. Include a control setup in your design.
The text mentions that "no man-made technology has been able to rival the microbial treatment of sewage." Critique this statement by considering the advantages and potential limitations of microbial sewage treatment, and propose one area where technology could enhance this biological process.
Propose a method to increase the efficiency of a sewage treatment plant (STP) that is currently overwhelmed by the volume of waste water, without building an entirely new plant.
A farmer has a choice between using chemical nitrogen fertilisers and using a biofertiliser containing and . Evaluate the long-term ecological and economic impacts of both choices on the farm's soil health and crop yield.
Describe the process of secondary or biological treatment of sewage. Mention the role of flocs and Biochemical Oxygen Demand (BOD).
List two examples of free-living nitrogen-fixing bacteria and two examples of nitrogen-fixing cyanobacteria that act as biofertilisers.
Three water samples were tested for Biochemical Oxygen Demand (BOD). The values recorded were , , and . The samples are known to be untreated sewage water, relatively clean river water, and secondary effluent from a sewage treatment plant (STP). Analyze these results to assign the correct label to each BOD value and justify your reasoning.
Contrast the mechanism of action of a broad-spectrum chemical pesticide with that of a biocontrol agent like a baculovirus. Analyze the ecological impact of each, focusing on specificity and effect on non-target organisms.
Evaluate the statement: "The discovery of antibiotics was the single most important contribution of microbes to human welfare." Justify your stance by comparing it with at least two other major microbial contributions discussed in the chapter.