1.1. History and Scope of Microbiology

Question 1

Why did people start studying microbiology?

Answer 1

People first began studying microbiology because of its effects on human health. In ancient times, people had very limited knowledge about the existence of microorganisms and how they could cause diseases. As a result, infectious diseases spread rapidly through populations, leading to high mortality rates.

Question 2

What is a zoonotic bacterium?

Answer 2

A bacterium that may be transmitted from animals to humans

Question 3

Zoonotic bacteria responsible for the Black Death or Bubonic Plague

Answer 3

Yersinia pestis

Question 4

How did the Bubonic Plague become a “plague”?

Answer 4

Yersinia pestis were found on fleas that cling onto rat fur which were then transported via boats to cities that were highly populated, killing 75-200 million people

Question 5

A thermophilic bacterium isolated from hot springs in Yellowstone National Park used to produce an enzyme called Taq polymerase

Answer 5

Thermus aquaticus

Question 6

What is a Taq polymerase?

Answer 6

A DNA polymerase that can withstand the high temperatures required during PCR, which makes it ideal for amplifying DNA sequences.

Question 7

How is Taq polymerase obtained from Thermus aquaticus?

Answer 7

Thermus aquaticus is isolated > cultured > cell lysis wherein cells are lysed to release its content including Taq polymerase > enzyme is isolated

Question 8

The most dominant life form on Earth; accounts for 60% of the planet’s biomass

Answer 8

Microbes

Question 9

How do microorganisms critically influence life?

Answer 9

1. Activity and evolution
2. Symbioses
3. Pathogenicity

Question 10

Activity and evolution

Answer 10

~ 4 billion years ago, there was no free oxygen at all; the Earth used to be anoxic. However, 2.46 billion years ago, cyanobacteria oxygenated the Earth, contributing to the evolution of complex life.

Question 11

Symbioses

Answer 11

Ruminants like cows form symbiotic relationships with bacteria that produce cellulase. Cows can digest the cellulose in grass, and the bacteria are provided with shelter in the cows’ rumen.

Question 12

Pathogenicity

Answer 12

Microbes can be pathogenic and produce illnesses. Diarrheal disease is the 2nd leading disease that kills children under 5 years old.

Question 13

Microbiology can be applied in many fields.

Answer 13

Microorganisms have major impacts on the world we interact with; hence, microbiology has myriad applications.

Question 14

What is Microbiology?

Answer 14

Study of organisms that are too small to be seen by the naked eye, what they are, how they work, and what they do.

Question 15

What invention gave rise to the study of Microbiology?

Answer 15

Microscope

Question 16

The first known description of microorganisms was made by ____ in his book ____ illustrating many microscopic images using a ____ microscope; this includes the fruiting structure of ____.

Answer 16

Robert Hooke
Micrographia
compound microscope
molds

Question 17

The first person to see bacteria in ___ using a hand lens (___ microscope); He wrote to Royal Society of London who made an English translation of his work.

Answer 17

Antoni van Leeuwenhoek
pepper water
simple

Question 18

A pioneer of protistology who developed microscopes to observe “animalcules”; rival of Leeuwenhoek; ridiculed for his “imaginative” portrayal of microscopic protists

Answer 18

Louis Joblot

Question 19

What is Spontaneous Generation?

Answer 19

An archaic theory proposing that life forms can spontaneously arise from non-living matter due to a “vital essence” in oxygen

Question 20

The progress of microbiology was slow due to the belief of spontaneous generation. True or False?

Answer 20

True

Question 21

Francesco Redi

Answer 21

Set up an experiment with three jars containing pieces of meat: one left open, one with a cork, and one with a gauze. Flies laid eggs in the first, did not in the second, and laid eggs on the gauze in the third. Flies are simply attracted to rotten meat; they do not arise from it.

Question 22

Ignaz Semmelweis

Answer 22

The maternity ward run by doctors who also operated on cadavers saw an 80% mortality rate, whereas the ward run by midwives saw only a 20% mortality rate. When a colleague died soon after dissecting a cadaver with a cut on his hand, Semmelweis realized something in the cadavers must be causing illness. After ordering doctors to wash their hands with chlorine before attending to patients, the mortality rate decreased to 20%.

Question 23

John Snow

Answer 23

During a cholera outbreak (Vibrio cholerae) in London, Snow mapped out the concentrations of sick individuals and found they were highly concentrated around a particular well. After interviewing people, he found a mother had been disposing of her infant’s diarrhea in a cesspit near the well — both of which apparently had holes that connected them to one another.

The only building in the immediate vicinity that was not affected by the outbreak was the bar, not because patrons drank alcohol, but because the water used to make the alcohol was boiled, killing the bacteria.

Question 24

Louis Pasteur

Answer 24

Disproved Spontaneous Generation using swan neck flasks filled with liquid broth. Dust and microorganisms from air remained trapped in the bend in the flask, and the liquid did not putrefy. But when the liquid was allowed to touch the dusty portion of the flask, it did not take long for it to spoil.

Question 25

Joseph Lister

Answer 25

Worked on bone fractures and realized that infections could arise where there were exposed wounds, so he used gaseous carbolic acid (a strong phenol) to sterilize both the room and the area around the patient.

Question 26

Set of criteria that establishes whether a certain organism is the cause of a particular disease.

Answer 26

The Koch Postulates

Question 27

The Koch Postulates

Answer 27

1. The suspected pathogen must be present in all cases of the disease and
   absent from healthy animals.
2. The disease organism must be isolated in pure culture.
3. Inoculation of a sample of the culture into a healthy, susceptible animal must
   produce the same disease.
4. The disease organism must be recovered from the newly inoculated animal.

Question 28

Who made the Koch Postulates?

Answer 28

Robert Hermann Koch

Question 29

Alexander Fleming

Answer 29

Noticed a zone of inhibition around a mold in a culture of Staphylococci and extracted penicillin from the fungus Penicillium notatum, which became the most widely used antibiotic (helped along by WW2’s need for medicine)

Question 30

Two Types of Microbiology

Answer 30

Basic Research Microbiology
Applied Microbiology