Ch 9Microbes in Human Welfare — Class 12 Zoology, concept-first.

Earth's biological world includes an enormous range of microscopic life -- bacteria, fungi, protozoa, certain algae, viruses, viroids and prions -- and these microbes make up a major share of everythi…

Many everyday foods and drinks are produced with the help of microbes. Lactic acid bacteria (LAB) such as Lactobacillus acidophilus, L.

Beyond household foods, microbes are harnessed industrially to manufacture a wide range of valuable products — beverages, antibiotics, organic acids, amino acids, vitamins, biofuels, single-cell prote…

Antibiotics are chemical substances made by microorganisms that kill or slow the growth of other, disease-causing microbes even at very low concentration; the word literally means 'against life'.

Yeasts have been used since ancient times to brew alcoholic beverages such as wine, beer, whisky, brandy and rum; zymology is the applied science that studies the biochemistry of fermentation and its…

Besides alcohol, industrial microbiology yields a range of organic acids, enzymes and pharmaceutical molecules.

Sewage is the waste generated daily in towns and cities, containing human excreta along with large amounts of biodegradable organic matter and pathogenic microbes; domestic wastewater is roughly 99% w…

The goal of wastewater treatment is to lower the Biochemical Oxygen Demand (BOD) — the amount of oxygen that would be consumed if all the organic matter in a litre of the water were oxidised by bacter…

A microbial fuel cell (MFC) is a bio-electrochemical device that generates electric current by exploiting the natural respiratory metabolism of bacteria, which is essentially a redox reaction moving e…

Biogas is a mixture of gases generated when organic matter is broken down anaerobically (without oxygen) by microbial action; it can be produced from agricultural waste, animal manure, municipal solid…

Widespread use of chemical pesticides and insecticides harms human health and pollutes the environment, so biocontrol — using microbes, or naturally occurring substances derived from plants and animal…

Biofertilisers are formulations of living microorganisms that enrich soil nutrient status and improve its physico-chemical properties — structure, texture, water-holding capacity, cation-exchange capa…

Bioremediation is the use of naturally occurring or genetically engineered microorganisms to reduce or degrade environmental pollutants; it is less expensive and more sustainable than other remediatio…

Bioremediation microbes are grouped by whether they need oxygen. Aerobic microbes break down pollutants — mainly pesticides and hydrocarbons — in the presence of oxygen (Fig.

The Evaluation exercises below test understanding across the whole chapter — from household fermented foods and industrial antibiotic/beverage/enzyme production, through sewage treatment, microbial fu…

Sample papers and previous-year board questions for this subject.