Applications of Microbes in Human Welfare — NEET Biology
📚 Practice ConceptFor more than a hundred years, microbes are being used to treat sewage (waste water) 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 heavy use of toxic pesticides for controlling pests. There is a need these days to push for use of biofertilisers in place of chemical fertilisers. It is clear from the diverse uses human beings have put microbes to that they play an important role in the welfare of human society.
Which of the above statements are correct? S1: Methanogens are a group of aerobic bacteria responsible for the production of biogas in anaerobic sludge digesters. S2: The primary components of biogas include methane, carbon dioxide, and hydrogen sulphide. S3: Methanobacterium is a common methanogen found exclusively in the rumen of cattle, contributing to cellulose digestion. S4: Biogas generation in a plant is indicated by the rising of a floating cover over the slurry due to gas accumulation. S5: The spent slurry from a biogas plant is generally discarded as a hazardous waste due to the presence of harmful anaerobic bacteria.
View solution & NCERT explanation
Correct answer: B — S2 and S4 only
The core concept is the understanding of biogas production, the microbes involved, its composition, and the fate of its byproducts. S1: Methanogens are bacteria that grow *anaerobically*, not aerobically, and produce biogas. Thus, S1 is NOT correct. S2: Biogas is a mixture of gases, predominantly methane, along with CO₂ and H₂S. Thus, S2 is correct. S3: Methanobacterium is indeed a common methanogen, and it is found in the rumen of cattle, but it is *also* commonly found in the anaerobic sludge during sewage treatment. The statement claims it's found *exclusively* in cattle rumen, which is false. Thus, S3 is NOT correct. S4: A floating cover is placed over the slurry in a biogas plant, which keeps on rising as the gas is produced in the tank, indicating biogas generation. Thus, S4 is correct. S5: The spent slurry is removed through another outlet and is used as fertiliser, not discarded as hazardous waste. Thus, S5 is NOT correct. Therefore, only statements S2 and S4 are correct. This corresponds to option B. Recap: The question tests knowledge about methanogens, biogas composition, the mechanism of biogas production in a plant, and the utility of spent slurry.
What does NCERT say about For more than hundred?
Has this concept appeared in NEET?
Which chapter is this from?
Through deep analysis of NEET and NTA, 176 of the 180 ReNEET 2026 (June 21) questions were already in the MedicNEET question bank before the exam.
176/180MedicNEET's Biology question bank is built from the same NCERT lines NTA picks repeatedly. Not random MCQs — questions crafted exactly like NTA crafts them.