Microbes in Human Welfare: MCQ Test

21. Which enzyme, produced by microbes, is commonly incorporated into detergent formulations to effectively remove oily stains from laundry?

• Pectinases
• Proteases
• Lipases
• Streptokinase

22. Bottled fruit juices are often clearer than homemade ones because they are clarified by the use of which enzymes?

• Lipases and Proteases
• Pectinases and Amylases
• Pectinases and Proteases
• Cellulases and Lipases

23. *Streptokinase*, modified by genetic engineering, is used as a 'clot buster' for patients suffering from myocardial infarction. From which bacterium is it produced?

• *Lactobacillus*
• *Streptococcus*
• *Methanobacterium*
• *Acetobacter aceti*

24. The immunosuppressive agent *Cyclosporin A*, vital for organ-transplant patients, is produced by which specific fungus?

• *Penicillium notatum*
• *Aspergillus niger*
• *Trichoderma polysporum*
• *Monascus purpureus*

25. *Statins*, which have been commercialized as blood-cholesterol lowering agents, are produced by which yeast?

• *Saccharomyces cerevisiae*
• *Monascus purpureus*
• *Trichoderma polysporum*
• *Penicillium notatum*

26. How do *Statins* work to lower blood cholesterol?

• By absorbing cholesterol from the blood
• By inhibiting the enzyme responsible for cholesterol synthesis
• By breaking down existing cholesterol molecules
• By increasing cholesterol excretion from the body

27. The municipal waste-water, containing large amounts of organic matter and many pathogenic microbes, is commonly referred to as:

• Effluent
• Biogas
• Sludge
• Sewage

28. What is the key characteristic of the primary treatment stage in sewage treatment plants (STPs)?

• Biological removal of organic matter
• Physical removal of particles
• Chemical disinfection of water
• Generation of biogas

29. In primary sewage treatment, what is the term for all the solids that settle down after filtration and sedimentation?

• Grit
• Primary sludge
• Flocs
• Activated sludge

30. The secondary treatment of sewage is also widely known as the:

• Chemical treatment
• Physical treatment
• Biological treatment
• Tertiary treatment

31. During secondary sewage treatment, useful aerobic microbes grow vigorously in aeration tanks, forming mesh-like structures called:

• Grits
• Biofilms
• Colonies
• Flocs

32. What does BOD stand for in the context of sewage treatment, and what does it measure indirectly?

• Biological Oxygen Deficiency; measure of bacterial count
• Biochemical Oxygen Demand; indirect measure of organic matter
• Bacterial Organic Decomposition; measure of pathogenic microbes
• Bio-oxidative Dissolution; indirect measure of inorganic pollutants

33. What is the relationship between the Biochemical Oxygen Demand (BOD) of waste water and its polluting potential?

• Lower BOD indicates higher polluting potential.
• Higher BOD indicates higher polluting potential.
• BOD has no direct relation to polluting potential.
• BOD only indicates the acidity of the water.

34. After the BOD of sewage is significantly reduced in secondary treatment, the bacterial 'flocs' sediment in a settling tank to form what?

• Primary sludge
• Effluent
• Activated sludge
• Biogas residue

35. Why is a small part of the activated sludge pumped back into the aeration tank?

• To increase its volume for disposal
• To serve as an inoculum for new treatment cycles
• To extract useful chemicals from it
• To reduce the overall treatment time

36. During the anaerobic digestion of the remaining activated sludge, which gases are typically produced by bacteria?

• Oxygen and Nitrogen
• Methane, Hydrogen sulphide, and Carbon dioxide
• Ammonia and Nitrous Oxide
• Sulphur dioxide and Methane

37. Which action plans were initiated by the Ministry of Environment and Forests in India to address pollution in major rivers?

• Clean India Mission and Swachh Bharat Abhiyan
• Ganga Action Plan and Yamuna Action Plan
• National River Linking Project
• Forest Conservation Act and Wildlife Protection Act

38. Biogas is predominantly a mixture of gases containing:

• Carbon dioxide
• Hydrogen sulphide
• Methane
• Nitrogen

39. Bacteria that grow anaerobically on cellulosic material and produce large amounts of methane, CO2, and H2 are collectively known as:

• Lactic acid bacteria
• Methanogens
• Denitrifiers
• Nitrifying bacteria

40. A common example of a methanogenic bacterium mentioned in the text is:

• *Lactobacillus*
• *Methanobacterium*
• *Streptococcus*
• *Azotobacter*