Microbes in Human Welfare Class 12 Notes

Microbes or microorganisms form a significant component of the biological systems on the earth. They are ubiquitous, present everywhere – in the soil, around us, in water, the air we breathe, and both in and on our body. Also, microbes are present on other animals and plants. They are so tiny, microscopic in nature, varying in shape and size. They can only be seen through the microscope. The different types of microbes are:

  • Algae
  • Bacteria
  • Fungi
  • Protozoa
  • Virus

Also See: Important Questions for Class 12 Chapter 10: Microbes in Human Welfare

For More Information On Microorganisms, Watch The Below Video:

Microbes in Human Welfare

Apart from the harmful and Infectious disease-causing pathogens, there are several useful microorganisms which are beneficial to humans in various ways. Some of the most important contributions of microbes to human welfare are discussed below.

In Household Products

  • Fermentation of milk to prepare yogurt.
  • Curdling of milk to prepare curd, cheese, and paneer.
  • Fermentation of dough, which is used for making bread, idli, and dosa.

In Industrial Products

  • Production Beverages like wine, beer, whiskey, brandy or rum.
  • Production antibiotics like Penicillin and other chemical substances to kill or retard the growth of disease-causing microbes.
  • Few Chemicals, Enzymes and other Bioactive Molecules are also produced by these microbes for various human uses.

See More: Role Of Microbes In Industrial Products

In Sewage Treatment

  • Sewage is treated in sewage treatment plans(STPs) before disposing of so as to make it less polluting which is naturally carried out by heterotrophic microbes present in the sewage. The treatment is carried out in two stages – Primary treatment, Secondary treatment or biological treatment
  • These processes reduce the BOD(biochemical oxygen demand) of the effluent significantly. BOD is the amount of oxygen that would be consumed if all the organic matter in one litre of water were oxidized by the bacteria. The sewage water is treated until the reduction of BOD as the BOD gauges the rate of uptake of oxygen by microbes in a water sample. Therefore, BOD is a measure of the organic matter present in water. Greater the BOD of wastewater, more is its polluting potential.

In Biogas Production

  • Methanobacterium, commonly found in anaerobic sludge facilitates sewage treatment. They are also found in the rumen of ruminants.
  • The excreta of cattle, known as gobar is bacteria-rich. Hence dung can be used for the generation of biogas commonly referred to gobar gas.

As Biocontrol Agents 

  • The utilization of biological methods to control plants pests and diseases is referred to as biocontrol which has been achieved through chemicals – pesticides and insecticides.
  • Use of biocontrol measures will reduce the dependence on toxic chemicals and pesticides to a greater extent.
  • Biological farming promotes life forms such as the inhabiting of the field, pests and predators, life cycles, feeding patterns that willl help in developing suitable means of biocontrol
  • Microbial biocontrol agents example – Bacillus thuringeinsis, available as dry spores, sprayed on vulnerable plants
  • Genetic engineering developments have enabled scientists to release B. thuringiensis toxins genes into plant body thereby making them resistant to attacks by insect pests. Example – Bt-cotton
  • Most of the baculoviruses used as biological control agents are in the genus Nucleopolyhedrovirus.

Microbes are also used as biofertilizers.

Few Important Questions

  • What are microbes?
  • What is fermentation?
  • List out the uses of microorganisms in Agriculture?
  • What is Biogas? Explain how microbes are used in the production of biogas
  • What is sewage? Write the difference between primary and secondary sewage treatment?

Learn more about microorganisms, its types, applications and its benefits to humans from the topics given below:

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