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1.1 |
World of Microorganisms |
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1. Classification of microorganisms
a) Bacteria
b) Fungi
c) Protozoa
d) Virus
e) Algae
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2. |
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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
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Example |
Bacillus sp., Vibro sp. |
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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
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Example |
Mushroom, yeast |
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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
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Example |
Paramecium sp., Ameoba sp. |
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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
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Example |
Chlamydomonus sp.
Spirogyra sp.
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3. Factors that affect the growth of microorganisms |
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Factors |
Explaination |
Humidity |
Damp conditions promote the growth and reproduction of microorganisms.
In dry condition, some bacteria will form cyst or spores.
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Light |
Microorganisms with chlorophyll prefer light condition.
Fungi and few bacteria prefer dark condition.
Exposure to UV light can kill microorganisms.
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Temperature |
Most microorganisms prefer 35 °C - 40 °C.
Low temperature in refrigerator reduce growth rate of microorganisms.
High temperature can kill microorganisms.
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pH value |
Optimum pH for most microorganisms is pH 7.
Some microorganism can live in environment with slightly acidic or alkaline.
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Nutrients |
The growth rate of microorganisms depends on amount of nutrients. |
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