Chapter 1: The Evolution of Microorganisms and Microbiology

Question 1

Microorganisms

Answer 1

are too small to be seen with the naked
eye and require the use of a → microscope
• They can be either unicellular or
multicellular

Question 2

Prokaryotes

Answer 2

do not have membrane bound
compartments

Question 3

Eukaryotes

Answer 3

are compartmentalized with membrane
bound organelles and a nucleus

Question 4

These cell difference led to the five kingdoms, which was
narrowed down to the three →

Answer 4

Domains
• Bacteria, Archaea, and Eukarya

Question 5

How we got to the three Domain system:

Answer 5

1. Use of the electron microscope to visualize fine
   structures of cells
2. Measurement of biochemical and physiological differences
3. Nucleic acid analysis (especially rRNA!)

Question 6

Domain Bacteria

Answer 6

• Single-celled → prokaryotes
• Have a cell wall that contains → peptidoglycan
• Members of the microbiome, which is found in and on the human body
• Help develop the immune system
• Digest food and produce vitamins in the large intestine
• Some do make you sick and cause → disease

Question 7

microbiome

Answer 7

the microorganisms in a particular environment (including the body or a part of the body)

Question 8

Domain Archaea

Answer 8

• Are also single-celled
prokaryotes:
• But…they are set apart from
bacteria by their ribosomal
RNA (rRNA), cell membranes,
and cell walls
• Found in extreme
environments with high
temperatures or high salt

Question 9

Domain Eukarya

Answer 9

• Includes plants, animals, and
microorganisms like protists and fungi

Question 10

Protists

Answer 10

are unicellular and are found in
two groups algae and protozoa

Question 11

Algae are →

Answer 11

photosynthetic

Question 12

Protozoa are

Answer 12

motile and have an
animal-like → metabolism

Question 13

Fungi are very ___

Answer 13

diverse, they range from unicellular
yeasts to multicellular molds and mushrooms

Can form health associations with some organisms
and cause disease in others

Question 14

How is the metabolism of a fungi beneficial?

Answer 14

they are very beneficial in
decomposition, the food industry, and medicines like penicillin

Question 15

Acellular Infectious Agents include:

Answer 15

Viruses, viroids, satellites, and prions

Question 16

Viruses

Answer 16

• Acellular entity that must invade a host cell
in order to → reproduce
• Consist of nucleic acid and a protein coat
• Cause disease in every known organism on
the planet

Question 17

Viroids

Answer 17

• Consist of only → RNA
• Cause plant diseases

Question 18

Satellites (“helper virus”)

Answer 18

• Consist of a nucleic acid inside of a protein shell
• Coinfect with viruses to complete their life cycle

Question 19

Prions

Answer 19

• Made of only → protein
• Cause → encephalopathy
• “Mad cow disease” in cattle and scrapie in sheep
• Can be transmitted to Humans through infected meat
or medical equipment

Question 20

Theories of the Origin of Life

Answer 20

• Earth is estimated to be 4.5-4.6 billion years old
• Life would have been unsupported for the first 100 million years because of harsh conditions
• Meteorite strikes → decreased
• Water appeared along with an
→atmosphere

• Life was present on Earth 3.5-3.8 billion years ago based on → molecular fossils
• It would have had:
• an orderly → structure
• the ability to obtain and use energy
• and → reproduce

Question 21

Probiont

Answer 21

were early cells

• Would have consisted of a single molecule that could do
cellular work and replicate

Question 22

• RNA can be ____ and act as ____ by forming
bonds between the ____ of proteins
• It can also store, copy, and express ____

Answer 22

• RNA can be catalytic and act as ribozymes by forming bonds between the amino acids of proteins
• It can also store, copy, and express genes

Question 23

Early cells formed when…

Answer 23

RNA was taken-up by a lipid vesicle called a liposome

Question 24

Liposome

Answer 24

Lipid vesicles

Question 25

RNA may have allowed for the formation of

Answer 25

DNA, which is similar structurally with a more stable → structure

and

ATP may have also formed from RNA since it is a ribonucleotide

Question 26

The evolution of metabolism is based on

Answer 26

• Earth’s atmosphere, which would have been
oxygen free and hot when life was forming
• Modern Archaea would be a descended
based on their ability to metabolize in harsh
conditions

Question 27

Atmospheric oxygen would have been formed by the evolution of ______ about 2.7 billion years ago

Answer 27

photosynthesis

• Modern cyanobacteria would have descended from
these organisms

Question 28

The production of oxygen allowed for the evolution of

Answer 28

aerobic respiration

Bacteria that use aerobic respiration became → mitochondria

Question 29

Evolution of the Three Domains

Answer 29

• Last universal common ancestor (LUCA) is the most recent organism that all three Domains → evolved

• Bacteria branch off LUCA, Archaea and Eukarya evolved independently from bacteria

• Archaea and Eukarya diverged from one another to
form separate Domains

IN OTHER WORDS….
—-oldest
LUCA 1ST
BACTERIA 2ND
ARCHAEA AND EUKARYA SPLIT TO BE 3RD AND 4TH
—-newest

Question 30

Endosymbiotic hypothesis

Answer 30

• Endosymbiotic hypothesis – energy related organelles became part of eukaryotic cells through endosymbiosis

Question 31

endosymbiosis

Answer 31

Once independent prokaryotic microbes evolved to live inside of early eukaryotes

Question 32

Bacteria that use aerobic respiration became →

Answer 32

mitochondria

Question 33

Photosynthetic cyanobacteria became →

Answer 33

chloroplasts

Question 34

Both organelles, mitochondria and chloroplasts, contain

(Tina’s note: I think mitochondria and chloroplast are the organelles she was referring to, but if you want to see for yourself its on slide 29)

Answer 34

• Bacteria DNA and → ribosomes
• Peptidoglycan is found between the membranes in
some organisms

Question 35

For anaerobic bacteria that produce hydrogen gas of CO2 became ______

Answer 35

hydrogenosomes
• Found in fermenting protists to make ATP

Question 36

Mutations

Answer 36

have been key to the evolution of cellular
microbes

• The best mutations allow for better reproduction or
survival and are passed on to future
generations
• This allowed for the formation of new genes and new species

Question 37

Genetic diversity is best in _____

Answer 37

sexually reproducing organisms

Question 38

Bacteria and archaea

Answer 38

• They can share genetic material through → horizontal gene transfer
• DNA is transferred from a donor to recipient
• Causes antibiotic resistance, new
virulence genes, and new metabolic
abilities

Question 39

Microbial Taxonomy

Answer 39

the rank-based classification, of bacteria

Question 40

Microbes are named using ________

Answer 40

binomial nomenclature system

• The name is Latin and italicized
• First part is the genus, which is → capitalized
• Second part is the species, which is → lowercase
• Ex. Yersinia pestis
• Can be abbreviated to → Y. pestis

Question 41

Microbiology came to light with the invention to the →

Answer 41

microscope

• From there, pure culture was used to growth bacteria in
isolation for study purposes

• Today we use molecular and genomic study

Question 42

Robert Hooke

Answer 42

published the first drawings of microorganisms in his book “Micrographia”
• Drew the fungus, Mucor
• Discussed a prototype for microscopes

Question 43

Antony van Leeuwenhoek

Answer 43

most likely built the prototype that was published by Hooke
• Microscope provided dark-field
illumination of liquid specimens
• Viewed bacteria and Protists

Question 44

spontaneous generation

Answer 44

• The theory of spontaneous generation was a belief that
living organisms can develop from nonliving matter

Question 45

Who challenged the theory of Spontaneous Generation?

Answer 45

Francesco Redi
• Preformed experiments using rotting meat, which was
believed to form maggots spontaneously

Question 46

How did Redi perform his experiment?

Answer 46

• Redi showed by covering or uncovering meat in jars that maggots were formed by flies, and they were not spontaneously generated

Question 47

Who ended the debate over spontaneous
generation?

Answer 47

Louise Pasture

Question 48

How did Louise Pasture ended the debate over spontaneous generation?

Answer 48

• He filtered air through cotton and found “plant-like” spores were removed from the air
• When put in sterile broth, microbial growth occurred

• To prove that the air had no
spontaneous generation ability be
created a swan-neck flask
• Nutrient solution was added into
the flask and→ boiled
• Air was exposed to the broth,
but dust and germs could not
get around the neck
• Growth only occurred is the neck
of the flask was→ broken

Question 49

John Tyndall

Answer 49

• Was able to show that dust carries → germs

• Showed that broth remained sterile even if it is exposed to air

• Discovered the existence of heat-resistant bacteria

Question 50

Ferdinand Cohn

Answer 50

showed that those heat-resistant
bacteria formed → endospores

Question 51

There was a time when disease was thought to be caused by the supernatural, poisonous air, or body imbalance of the four humors _____, ______, ______, and ______.

Answer 51

blood, phlegm, yellow bile, and black
bile

Question 52

Germ theory of disease states that

Answer 52

microorganisms cause disease

Question 53

How did Pasture use the Germ Theory of Disease to help with the French wine industry?

Answer 53

• Showed that contaminating bacteria was spoiling the wine
• Created pasteurization, which killed spoiling microbes but did not harm the wine

Question 54

pasteurization

Answer 54

kills spoiling microbes without harming the microbe’s host (milk, wine, etc.)

Question 55

Robert Koch

Answer 55

was able to show relationships between specific microorganisms and a disease
• Koch’s Postulates
• Worked with Guinea Pigs and
Pure culture

Question 56

Steps of Koch’s Postulates

Answer 56

1. The microorganism must be present in every case of the disease but absent from health organisms
2. The suspected microorganisms must be isolated and grown in a pure culture.
3. The same disease must result when the isolates microorganism is inoculated into a healthy host

4.The same microorganisms must be isolated again from the diseased host.

Question 57

Koch’s Postulates are still used, but they have some downsides. What are these current inconveniences?

Answer 57

• Koch’s postulates are still used but they are not always feasible

• Some causative agents, like Mycobacterium leprae, cannot be growth in pure culture

• There is no animal model available to test the
postulates

Question 58

What is the most common method of Koch’s
postulates?

Answer 58

Genetic analysis, study genes associated with virulence.

Question 59

Pasture and Pierre Roux found that if you incubate cultures for long periods of time, they will not be able to

Answer 59

cause disease

• Pasture made an attenuated vaccine against → rabies
• It was given to a 9-year-old boy that was bitten by a rabid dog

Question 60

Edward Jenner

Answer 60

created a smallpox vaccine with material
from cowpox lesions