Microorganisms

World of Microorganisms

1.1

World of Microorganisms

1. Classification of microorganisms

a) Bacteria

b) Fungi

c) Protozoa

d) Virus

e) Algae

2.

	Bacteria
Size	0.2 µm - 10 µm
Shape	Coccus, bacillus, spirilla, vibrio
Nutrition	Autotrophic, saprophytic, parasitic
Habitat	Air, water, soil, food, bodies of other organisms
Method of reproduction	Asexual: binary fission Sexual: conjugation
Example	Bacillus sp., Vibro sp.

	Fungi
Size	10 µm - 100 µm
Shape	Spherical, filamentous
Nutrition	Saprophytes, parasitic
Habitat	Places with decaying matter, faeces, animal skin and food
Method of reproduction	Asexual: budding, spore formation Sexual: conjugation
Example	Mushroom, yeast

	Protozoa
Size	5 µm - 250 µm
Shape	Spherical, spindle-shaped, irregular shaped
Nutrition	Saprophytic, parasitic
Habitat	Aquatic habitats, damp place, bodies of living organisms
Methode of reproduction	Asexual: binary fission Sexual: conjugation
Example	Paramecium sp., Ameoba sp.

	Algae
Size	1 µm - 100 µm
Shape	Spherical, oval-shaped, filamentous
Nutrition	Autotrophic
Habitat	Aquatic habitats, damp place
Methode of reproduction	Asexual: binary fission, spore formation Sexual: conjugation
Example	Chlamydomonus sp. Spirogyra sp.

3. Factors that affect the growth of microorganisms

Factors	Explaination
Humidity	Damp conditions promote the growth and reproduction of microorganisms. In dry condition, some bacteria will form cyst or spores.
Light	Microorganisms with chlorophyll prefer light condition. Fungi and few bacteria prefer dark condition. Exposure to UV light can kill microorganisms.
Temperature	Most microorganisms prefer 35 °C - 40 °C. Low temperature in refrigerator reduce growth rate of microorganisms. High temperature can kill microorganisms.
pH value	Optimum pH for most microorganisms is pH 7. Some microorganism can live in environment with slightly acidic or alkaline.
Nutrients	The growth rate of microorganisms depends on amount of nutrients.