2. CONTENT
Definition of terms
Historical development of microbiology
Ecological relationship
Factors promoting growth & development of microorganisms
Importance of microorganisms
Classification of microorganisms
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5. PARASITOLOGY:
Is the study of parasites, their hosts, and the relationship between
them.
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6. IMMUNOLOGY:
Is the study of the immune system, which protects us from
infection
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7. History
People attributed diseases to witchcraft and the devil.
Later they believed disease was caused by miasma (an unpleasant
or unhealthy smell)
1632-1723 Antoni van Leeuwenhoek: was the first to demonstrate
the presence of micro-organisms via a microscope
Louis Pasteur: showed that there were germs present in the
environment
Louis Pasteur: opened the field of sterilization
He also developed vaccines (anthrax vaccine)
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8. History cont..
Robert Koch’s contribution:
Described methods of preparing cultures
Discovered the causative agents of:
Tuberculosis
Cholera
Fleming and Chain developed penicillin in 1929 from a fungus
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9. History cont..
For more of the history, check the class email for the handout on
History of microbiology and immunology
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10. Ecological Characteristics
Host: Is an organism that harbors a guest organism
Parasites: Is an organism that lives within or on a host
Pathogens: Is a biological agent that causes disease or illness to its
host.
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11. Ecological relationships
The interaction among organisms within or between overlapping
niches can be characterized into 5 types of relationships:
1. Competition
2. Predation
3. Commensalism
4. Mutualism
5. Parasitism
Symbiosis
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12. 1. Competition
Competition is when
individuals or populations
compete for the same resource
An example is lions and hyenas
that compete for prey.
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13. 2. Predation
Predation is when one organism
eats another organism to obtain
nutrients.
The organism that is eaten is
called the prey.
Examples are owls that eat mice,
and lions that eat gazelles.
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14. 3. Commensalism
Commensalism is a relationship
in which one organism benefits
while the other is neither
helped nor harmed.
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15. 4. Parasitism
Parasitism is a relationship in which
one organism benefits and the other
organism is harmed, but not always
killed.
The organism that benefits is called
the parasite,
The one that is harmed is the host.
Example such as intestinal worms
that live inside the host
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16. 5. Mutualism
Mutualism is a
relationship in which
both species benefit.
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18. Factors promoting growth and development
of micro-organisms
Nutrients: All microorganisms need food
Temperature: Very high and very low temperatures discourage
growth
pH Levels: most organisms prefer neutral pH
Moisture: All microorganisms require some level of water
Oxygen requirement: Some organisms are anaerobes and aerobes
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19. Importance of Micro-organisms
For vaccine production e.g polio vaccine from the virus
For production of food: yeast used to make bread, bacteria
important for making yoghurt.
Soil microbes help to recycle nutrients:
Used in the brewing of alcohol
Fungi help in the degradation of living things that have died
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