Page 20 - Genius Kidz Prudence Learning Sc-8
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(ii) Oval or Spherical shape bacilli : mitochondria and other cell organelles.
Spherical shape bacilli are called Locomotory organ of a bacterium are
cocii. (sing. Coccus). For example- flagella.
Streptococcus, Saricina and
Micrococcus.
Bacterial structure
Oval or spherical shape bacilli
(e) Types of Bacteria : Bacteria can be
(iii) Spiral or Comma shaped bacilli : classified on the basis of chemical
Comma shaped bacilli are called composition of their cell wall :
s p i r i l l a . F o r e x a m p l e .
(i) Gram positive bacteria : The cell wall
Camphylobacter and Triponema.
of gram positive bacteria is thick. It is
made up of many layers of
peptidoglycon chains and techoic
acids.
(ii) Gram negative bacteria : The cell
wall of gram negative bacteria is
thin. It is made up of a few layers of
peptidoglycon surrounded by a lipid
m e m b r a n e c o m p o s e d o f
Spiral shape bacilli
l i p o p o l y s a c c h a r i d e a n d
(d) Structure : Bacteria are unicellular. lipoproteins.
Bacterial cells enclosed by a lipid (f) Nutrition : Bacteria can be autotrophic
membrane or cell membrane. Outside or heterotrophic. They are mostly
the membrane, there is a protective saprophytes i.e. they feed on dead and
covering called cell wall. Bacterial cells decaying matter but some can be
consist of genetic material that is not parasites, that is, they obtain nutrition
bounded by a nuclear membrane. A from host organism in which they
bacillus thus lacks a true nucleus, reside.
(g) Reproduction : As already read in class
VII, bacteria show both sexual and
The largest organism on Earth is fungus.
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