Monera

This kingdom comprises of single-celled prokaryotic bacteria, filamentous actinomycetes and photosynthetic blue-green algae (cyanobacteria). Carl Woese (1977) divided Monera into Archaebacteria (primitive bacteria) and Eubacteria (true bacteria).

Bacteria: Bacteria are unicellular and generally occur singly. Some of them are found in groups. They are named according to their shapes.

1. Rod-shaped bacteria are called bacilli (singular: bacillus), e.g., Bacillus anthracis, which causes the disease anthrax.

2. Spherical bacteria are called cocci (singular: coccus), e.g., Streptococcus pneumoniae, which causes the disease pneumonia.

3. Other types are spiral bacteria called spirilla. eg: Spirillium and comma-shaped called vibrio. eg: vibrio cholera.

Bacteria lack nuclear membrane. Therefore, a distinct nucleus and nucleolus are absent. Bacteria also lack membrane-bound organelles like endoplasmic reticulum, Golgi complex, mitochondria and plastids. Most bacteria lack chlorophyll, hence they are heterotrophic (saprophytic or parasitic). However, a few bacteria possess chlorophyll and are autotrophic. Remember that all parasitic bacteria do not cause diseases. There are many that live harmlessly in our intestine.

Deopending on the composition of the cell wall, some bacteria retain a certain type of stain, while others lose it. The method of distinguishing bacteria by staining them with Gram's stain was developed by a Danish bacteriologist Christian Gram. Bacteria with a particular type of cell wall that retain the stain after being washed with an organic solvent are called Gram positive bacteria and that do not retain the stain are called as the stain are called Gram negative.

Many bacteria have flagella or cilia, while some have thin outgrowths called fimbariae. Some bacteria secrete a slimy material which covers them in a protective slime layer or capsule.

Sample Questions

(More Questions for each concept available in Login)

Question : 1

___________________ kingdom is characterized by absence of membrane-bound cell organelles.
A. Protista	B. Fungi	C. Monera	D. Animalia
Right Option : C
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Question : 2

The largest bacteria is of ______________ type.
A. Bacillus	B. Coccus	C. Spirillus	D. Spherical
Right Option : B
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Question : 3

Mitochondria are absent in ________________________
A. Green algae	B. Brown algae	C. Cynobacteria and bacteria	D. All the above
Right Option : C
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