Bacteria and mollicutes: General morphological characteristics, basic methods of classification and reproduction
Morphological characteristics:
Bacteria are single-celled organisms.
They lack organelles such as chloroplasts and mitochondria.
Do not have the true nucleus.
That does not have a nuclear membrane.
Bacteria also have a cell membrane and a cell wall that is often made of peptidoglycan.
Reproduction occurs through binary fission. \
Most numerous organisms on earth.
Microscopic prokaryotes (no nucleus non membrane-bound organelles).
Contain ribosomes.
Classification of Bacteria Bacteria can be classified based on the following characterstics:-
1. Based on shape- Coccus, Bacillus, Spirillum, Vibrio etc.
2. Based on staining characters- Gram positive bacteria, Gram negative bacteria
3. Based on arrangement of flagella- atrichous bacteria, Monotrichous bacteria, Amphitrichous bacteria,
Lopotrichous bacteria, Peritrichous bacteria.
4. Based on nutrition requirement- Autotrophs, Heterotrophs, Chemoautotrophs, Saprophytic bacteria,
Symbiotic bacteria, Pathogenic bacteria
5. Based on oxygen requirement- Aerobic, Anaerobic
6. Based on temperature dependence- Thermophilic, Mesothermic, Hypoctermic
