Lec 1: Introduction To Microbiology

Question 1

What is Microbiology?

Answer 1

Microbiology is the study of microorganisms -life forms too small to be seen by the human eye

Prokaryotes: Bacteria,
Archaea Eukaryotes: Algae, Fungi, Protozoa Viruses/Phages

Question 2

Why should we study microorganisms?

Answer 2

-Microorganisms are involved in everyday things
-Contribute to many fields like biotech to healthcare
-Microbiology has allowed us to improve health outcomes through research and medicine

Question 3

Microbiology In The News

Answer 3

-Microbiology is always relevant from Covid-19 to contaminations in food companies
-Advances in CRISPR research and others have allowed us to improve outcomes in diseases caused by infections

Question 4

Microbes History in Earth

Answer 4

-Microbes have been around the longest as the first organisms on Earth
-Since they have been able to survive with only inorganic compounds —> Phototrophically —> Aerobically
-Microbes alone make up most of the biomass ( C, N, Ph - from their cellular components)

Question 5

Microbes and Black Death

Answer 5

-Was caused by a microbe Yersina pestis spread via fleas living on rats
-mass necrosis of tissue (turns black)
-80% of patients die within 8 days of infection Killed 30-50% of the European population

Question 6

Early Microbiologist

Answer 6

-Robert Hooke- first known description of microorganisms (1665)
-Antoni van Leeuwenhoek: first person to see bacteria (1676) -called them “animalcules”

Question 7

Early Beliefs For Where Microbes Come From

Answer 7

1. Spontaneous Generation: Microbes Appear Magically
2. Microbes from air grow in culture

Question 8

Louis Pasteur Beliefs and Criticism

Answer 8

Did not believe in spontaneous generation
Used heat and seal to prevent microbial growth in liquid

Two criticisms from others:
-Heating destroys life-generating substances
-”fresh air” necessary for spontaneous generation

Question 9

Pasteur’s Experiments - Criticism#1 (see Lec slides for image)

Answer 9

Criticism #1: Heat destroys life-generating substances

Pasteur Did As Follows:
1. Sealed flask
2. Heated it
3. Opened it to air
4. Culture was contaminated

-Showed heating does not destroy life-generating substance

Question 10

Pasture Experiments- Criticism #2 (see Lec slides for image)

Answer 10

Criticism #2: ”Fresh air” is required for spontaneous generation

Pasture did as follows:

1. Culture in flask
2. Heated flask to make a curved dip
3. Heated flask to sterilize
4. Found that microbes were trapped on dip but did not contaminate the culture

Showed aired actually carried microbes and did not directly contaminate media unless in contact with

Question 11

Robert Koch- The Germ Theory of Disease

Answer 11

Developed an expirement to show microbes cause disease:

1. The suspected pathogen must be present in all cases of the disease and absent from healthy animals.
2. The suspected pathogen must be grown in pure culture.
3. Cells from a pure culture of the suspected pathogen must cause disease in a healthy animal.
4. The suspected pathogen must be reisolated and shown to be the same as the original.

Using this method Koch was able to discover many different causations for different diseases