Class 12 Biology - MAHARASHTRA
Microbes in Human Welfare
The chapter 'Microbes in Human Welfare' explores the beneficial roles of microorganisms in daily life, industrial production, sewage treatment, pest control, and as biofertilisers. For Maharashtra State Board (MSBSHSE) Class 12 students, this is a high-scoring ecology-based chapter. Board exams frequently test direct factual questions, scientific names of microbes (which must be underlined correctly), and their specific products like antibiotics, enzymes, and organic acids. Understanding these applications bridges the gap between theoretical biology and real-world biotechnology, making it vital for both board theory papers and MHT-CET entrance exams.
Start Learning FreeKey Concepts
Microbes in Household Products
Microorganisms like Lactobacillus convert milk into curd by producing lactic acid, while Saccharomyces cerevisiae (brewer's yeast) is used for fermenting dough in idli, dosa, and bread-making.
Microbes in Industrial Production
Large-scale production of beverages and antibiotics is carried out in massive vessels called fermenters using specific microbes like Aspergillus niger for citric acid and Penicillium notatum for penicillin.
Microbes in Sewage Treatment
Municipal waste water is treated in primary and secondary (biological) treatment plants where aerobic and anaerobic microbes digest organic matter, significantly reducing the Biochemical Oxygen Demand (BOD).
Microbes as Biocontrol Agents
Natural methods of pest and disease control using biological organisms, such as Bacillus thuringiensis (Bt) to control butterfly caterpillars and Trichoderma species against plant pathogens, avoiding harmful chemicals.
Microbes as Biofertilisers
Organisms that enrich nutrient quality of the soil through nitrogen fixation and phosphate solubilization, exemplified by Rhizobium in legume root nodules, Azospirillum, and Mycorrhiza fungi.
Important Formulas
Board Exam Info
In the Maharashtra (MSBSHSE) Class 12 Biology board exam, this chapter typically carries about 3 to 4 marks without options, and up to 6 marks with options. Common question types include matching columns (pairing microbes with their products), identifying scientific names correctly, short answer questions on sewage treatment steps, and applications of biofertilisers.
Frequently Asked Questions
Is it mandatory to underline scientific names of microbes in board exams?
Yes, according to standard biological nomenclature rules, handwritten scientific names like Lactobacillus or Saccharomyces cerevisiae must be separately underlined, and printed ones must be in italics to avoid losing marks.
What is the difference between primary and secondary sewage treatment?
Primary treatment is a physical process involving filtration and sedimentation to remove floating and grit particles. Secondary treatment is a biological process where aerobic and anaerobic microbes are used to consume organic waste and lower the BOD.
How does Mycorrhiza act as a biofertiliser?
Mycorrhiza is a symbiotic association between fungi and roots of higher plants. The fungal symbiont absorbs phosphorus from soil and passes it to the plant, while also providing resistance to root-borne pathogens and drought.
Learn Microbes in Human Welfare with Your AI Tutor
10 different ways to study this chapter. Free for 3 chapters per day.
Lecture
Key Points
Interactive
Quiz
Flashcards