Types of Micro-organisms

Micro-organisms are classified into four major groups:

• Bacteria (Singular bacterium)
• Fungi (Singular fungus)
• Protozoans
• Algae (Singular alga)
• Viruses (Singular virus)

BACTERIA:

These are simple, single-celled organisms that can be found everywhere. Bacteria are found in three different shapes:

• Rod-shaped, called bacilli
• Spherical, called cocci
• Spiral, called spirilla.

FUNGI:

They are plant-like organisms without the green pigment (chlorophyll). Fungi may be unicellular (yeast) or multicellular (Bread mould, Penicillium, Aspergillus). They are preferably found at moist places.

PROTOZOA

They are unicellular animal-like organisms. They can move from place to place and also capture food.Amoeba, Giardia and Paramecium are examples of protozoa.

ALGAE:

These are plant-like organisms that have cell walls and chlorophyll. Almost all algae live in water. Algae can be unicellular (eg. Chlamydomonas) or multicellular (eg. Spirogyra).

VIRUSES