NCERT Book Class 12 Biology Chapter 8 Microbes in Human Welfare

CHAPTER 8

MICROBES IN HUMAN WELFARE

8.1 Microbes in Household
Products

8.2 Microbes in Industrial Besides macroscopic plants and animals, microbes are
Products the major components of biological systems on this earth.
8.3 Microbes in Sewage You have studied about the diversity of living organisms
Treatment in Class XI. Do you remember which Kingdoms among
the living organisms contain micro-organisms? Which are
8.4 Microbes in Production of
Biogas the ones that are only microscopic? Microbes are present
everywhere – in soil, water, air, inside our bodies and that
8.5 Microbes as Biocontrol
of other animals and plants. They are present even at sites
Agents
where no other life-form could possibly exist– sites such
8.6 Microbes as Biofertilisers as deep inside the geysers (thermal vents) where the
temperature may be as high as 1000C, deep in the soil,
under the layers of snow several metres thick, and in highly
acidic environments. Microbes are diverse– protozoa,
bacteria, fungi and microscopic animal and plant viruses,
viroids and also prions that are proteinacious infectious
agents. Some of the microbes are shown in Figures 8.1
and 8.2.
Microbes like bacteria and many fungi can be grown
on nutritive media to form colonies (Figure 8.3), that can
be seen with the naked eyes. Such cultures are useful in
studies on micro-organisms.