By Ajay Anand
Bacteria are kept under Kingdom Monera.
They are prokaryotic and possess cell wall.
Cell wall is composed of polysaccharides and amino acids.
Bacteria can be autotrophic and heterotrophic.
Autotrophic bacteria can be chemosynthetic or photosynthetic.
Heterotrophic bacteria can be saprophytic or parasitic.
Based on their shape, bacteria are classified into four types:
Cocci (Spherical),
Bacilli (Rod-shaped),
Vibrio (Comma-shaped) and
Spirilla (Spiral)
These are believed to be the oldest living beings.
The archaebacteria live in some of the harshest habitats; like sulphur springs, volcanic crater, etc.
| Archaebacteria | Habitat |
|---|---|
| Halophiles | Extremely Salty Areas |
| Thermoacidophiles | Hot Spring |
| Methanogens | Marshy areas and gut of ruminating animals |
Also called the ‘true bacteria’.
They possess a rigid cell wall, and a flagellum (in motile bacteria).
The cyanobacteria are examples of eubacteria.
Also called ‘blue-green algae’ as they contain chlorophyll.
Examples: Nostoc and Anabaena.
Bacteria usually reproduce by binary fission.
They also reproduce by spore formation.
They also reproduce by adopting a primitive type of DNA transfer.
This is similar to sexual reproduction.