Unit 1

Question 1

• Describe contributions of Hippocrates, Thucydides, Varro, Leeuwenhoek, Pasteur and Koch

Answer 1

Hippocrates, the “father of Western medicine,” believed that diseases had natural, not supernatural, causes.

The historian Thucydides observed that survivors of the Athenian plague were subsequently immune to the infection.

Marcus Terentius Varro proposed that disease could be caused by “certain minute creatures . . . which cannot be seen by the eye.” (credit c: modification of work by Alessandro Antonelli)

Antonie van Leeuwenhoek, using a microscope, was the first to actually describe observations of bacteria, in 1675.

Louis Pasteur (1822–1895) is credited with numerous innovations that advanced the fields of microbiology and immunology.

Robert Koch (1843–1910) identified the specific microbes that cause anthrax, cholera, and tuberculosis.

Question 2

• Describe how microorganisms are classified and distinguished as unique species

Answer 2

Taxonomy – scientific classification of living organisms.
Originally based on physical characteristics
Carolus Linnaeus – famous for proposing a standard taxonomic system (Linnaean taxonomy)
Avoid confusion about colloquial names
Kingdom, class, order, family, genus, species

Question 3

Bacteria ( Prokaryotic )

Answer 3

No nucleus
Most have peptidoglycan cell walls
Described by cell morphology
Found everywhere!
Some are photosynthetic
Most are harmless / helpful
Some are pathogens

Question 4

Archaea ( prokaryotic )

Answer 4

Archaea
No nucleus
Pseudopeptidoglycan
Seriously found everywhere! (extreme environments)
Some are photosynthetic
Not known to be pathogenic, even though some are human commensals

Question 5

Shapes of microorganisms

Answer 5

coccus - round
Bacillus - rod
Vibrio - curved rod
Spiralium - loose spiral
Spirochete - more pronounced spirals

Question 6

Eukaryotic Organisms different types

Answer 6

Algae – photosynthetic
Uni- or multi- cellular and plant-like (cellulose)
Useful to environment, food industry and the lab

Protozoa – some are photosynthetic
Very diverse in movement (cilia, flagella, pseudopods)
Maybe free-living or parasitic; harmless or pathogens
Plasmodium falciparum – malaria
Trypnosoma brucei – African sleeping sickness

Question 7

Fungi ( is eukaryotic )

Answer 7

While plant-like, they are more closely related to animals than plants
Chitin walls rather than cellulose
Non-photosynthetic
Unicellular- yeasts
Many are beneficial or non-harmful (think bread and other fermented stuff (not ETHOS approved)
Some cause disease (yeast infections)
Multicellular- molds & mushrooms
Tend to be decomposers and can cause disease
Pharmaceuticals: Penicillin and cyclosporine

Question 8

Helminths ( are Eukaryotic )

Answer 8

Macroscopic as worms, but fall within microbiology because eggs and larvae are microscopic
Many are transmitted fecal-oral, so are prevented by treating drinking water

Question 9

Viruses ( Acellular )

Answer 9

DNA or RNA encased in a protein coat
Must be in a host cell to replicate (co-opt host)
Can infect both eukaryotic and prokaryotic hosts
Many don’t cause disease