MICROORGANISMS
2
CHAPTER
CONTENTS MICROORGANISMS
Occurence of microbes Bacteria Alage Fungi Protozoa Viruses
Major groups of microorganism
CLASSIFICATION OF MICROORGANISMS
Classification of microorganism
Microbes are mainly classified into five major
Uses of bacteria, fungi, Algae, Protozoa
groups :
Harmful microorganism Bacteria :
Bacteria (singular: bacterium) are single-celled
Method of food preservation organisms that vary in shape and size. Some
Nitrogen fixation
bacteria are round or oval (coccus), others are
rod-shaped (bacillus) or spiral. Some bacteria are
autotrophic as they contain chlorophyll, but most
The organisms which are too small to be seen by the of them are heterotrophic, showing saprophytic or
naked eyes & can be seen only through a microscope parasitic mode of nutrition.
are called microorganisms.
OCCURENCE OF MICROBES
Microorganisms are present everywhere in air,
soil, water, food stuffs, sewage, waste as well as
inside of any living bodies. The maximum
number of microbes are found in natural substrate
which are rich in organic food, and have a
suitable temperature and moisture for their growth
and multiplication. An important fact about these
microorganisms is that they are strong. They can
survive extreme conditions of temperature and Figure : DIFFERENT TYPES OF BACTERIA
dryness by forming a cyst, which is a hard outer
coat around their bodies. Algae :
Autotrophic organisms having undifferentiated
MAJOR GROUPS OF MICROORGANISMS plant bodies are called algae (singular: alga).
Microorganisms are present in the air, water, food Algae occur abundantly, like grass in aquatic
and even inside our bodies. While a majority of habitats and are also called 'grass of water'.
the microbes are harmless, some of them have the
capability of causing dangerous diseases.
, Figure : SOME FORMS OF PROTOZOA
Viruses :
A virus is a microorganism which exhibits
characteristics of living as well as non-living
Figure : SOME FORMS OF ALGAE
thing. Viruses exhibit a variety of shapes, having
Fungi : simple structure. Reproducing only inside a living
organism, viruses can cause many diseases.
Fungi (singular: fungus) are a group of plant-like
organisms exhibiting heterophic (saprophytic or
parasitic) nutrition. They are commonly found on
bread, leather, cotton, paper, etc. Fungi grow
vigorously in damp, warm, dark places, Yeast,
moulds and mushrooms are forms of fungi. Yeast
is commonly used for baking bread, cakes, etc. The
yeast ferments sugar present in the wheat and
converts it to carbon dioxide and alcohol.
Figure : SOME FORMS OF VIRUSES
USES OF BACTERIA
In Medicine :
(i) Antibiotics : Many well known antibiotics such as
streptomycin, aureomycin and chloromycin are
Figure : SOME FORMS OF FUNGI obtained from bacteria.
In Agriculture :
Protozoa : (i) Decay of Organic Substances : Bacteria act on
Unicellular organisms that exhibit animal-like dead bodies of animals and plants and convert
characteristics are called protozoa (singular: various complex organic compounds into simple
protozoan). The word protozoan literally means inorganic substances. Thus, bacteria help in
'the first animal'. Most protozoa are heterotrophic. recycling of matter.
2
CHAPTER
CONTENTS MICROORGANISMS
Occurence of microbes Bacteria Alage Fungi Protozoa Viruses
Major groups of microorganism
CLASSIFICATION OF MICROORGANISMS
Classification of microorganism
Microbes are mainly classified into five major
Uses of bacteria, fungi, Algae, Protozoa
groups :
Harmful microorganism Bacteria :
Bacteria (singular: bacterium) are single-celled
Method of food preservation organisms that vary in shape and size. Some
Nitrogen fixation
bacteria are round or oval (coccus), others are
rod-shaped (bacillus) or spiral. Some bacteria are
autotrophic as they contain chlorophyll, but most
The organisms which are too small to be seen by the of them are heterotrophic, showing saprophytic or
naked eyes & can be seen only through a microscope parasitic mode of nutrition.
are called microorganisms.
OCCURENCE OF MICROBES
Microorganisms are present everywhere in air,
soil, water, food stuffs, sewage, waste as well as
inside of any living bodies. The maximum
number of microbes are found in natural substrate
which are rich in organic food, and have a
suitable temperature and moisture for their growth
and multiplication. An important fact about these
microorganisms is that they are strong. They can
survive extreme conditions of temperature and Figure : DIFFERENT TYPES OF BACTERIA
dryness by forming a cyst, which is a hard outer
coat around their bodies. Algae :
Autotrophic organisms having undifferentiated
MAJOR GROUPS OF MICROORGANISMS plant bodies are called algae (singular: alga).
Microorganisms are present in the air, water, food Algae occur abundantly, like grass in aquatic
and even inside our bodies. While a majority of habitats and are also called 'grass of water'.
the microbes are harmless, some of them have the
capability of causing dangerous diseases.
, Figure : SOME FORMS OF PROTOZOA
Viruses :
A virus is a microorganism which exhibits
characteristics of living as well as non-living
Figure : SOME FORMS OF ALGAE
thing. Viruses exhibit a variety of shapes, having
Fungi : simple structure. Reproducing only inside a living
organism, viruses can cause many diseases.
Fungi (singular: fungus) are a group of plant-like
organisms exhibiting heterophic (saprophytic or
parasitic) nutrition. They are commonly found on
bread, leather, cotton, paper, etc. Fungi grow
vigorously in damp, warm, dark places, Yeast,
moulds and mushrooms are forms of fungi. Yeast
is commonly used for baking bread, cakes, etc. The
yeast ferments sugar present in the wheat and
converts it to carbon dioxide and alcohol.
Figure : SOME FORMS OF VIRUSES
USES OF BACTERIA
In Medicine :
(i) Antibiotics : Many well known antibiotics such as
streptomycin, aureomycin and chloromycin are
Figure : SOME FORMS OF FUNGI obtained from bacteria.
In Agriculture :
Protozoa : (i) Decay of Organic Substances : Bacteria act on
Unicellular organisms that exhibit animal-like dead bodies of animals and plants and convert
characteristics are called protozoa (singular: various complex organic compounds into simple
protozoan). The word protozoan literally means inorganic substances. Thus, bacteria help in
'the first animal'. Most protozoa are heterotrophic. recycling of matter.
