Ch 1 History

Question 1

What is a microbe?

Answer 1

Microbes are minuscule organisms that require a microscope to be seen

Question 2

What are the major different groups of prokaryotic microorganisms?

Answer 2

Bacteria and archaea

Question 3

What are the defining characteristics of bacteria?

Answer 3

1. Some bacteria have been identified as pathogens
2. Cell walls contain peptidoglycan
3. Can be photosynthetic or not photosynthetic

Question 4

What are the defining characteristics of archaea?

Answer 4

1. They have not been identified as pathogens

2. Cell wall is made up of psuedopeptidoglycan

Question 5

What are the similarities between archaea and bacteria?

Answer 5

1. Both can grow in various environments (can also live in the human body)
2. unicellular, prokaryotic organisms

Question 6

What are the major different groups of eukaryotic microorganisms?

Answer 6

Algae, protozoa, fungi, helminths

Question 7

What are the defining characteristics of algae?

Answer 7

1. Can be multicellular or unicellular

2. Derive their energy from photosynthesis

Question 8

What are the defining characteristics of protozoa?

Answer 8

1. They are unicellular
2. Have complex cell structures
3. Can move either through extensions of their cytoplasm or cell membrane or with the help of cilia and flagella

Question 9

What are the defining characteristics of fungi?

Answer 9

1. Can be multicellular or unicellular (mold)

2. Cell wall is made up of chitin, not photosynthetic

Question 10

Mold

Answer 10

Multicellular fungi that is responsible for decomposing dead plants and animals

Question 11

What are the defining characteristics of helminths?

Answer 11

They are multicellular parasitic worms that cause disease.

- technically they are not microorganisms since they can be seen with the naked eye

Question 12

Van Leeuwenhoek

Answer 12

He was the first scientist to create a lens that was powerful enough to see microorganisms.
He invented the first microscope and discovered the first microorganisms.

Question 13

Pasteur

Answer 13

1) He showed that microbes caused fermentation, invented pasteurization, and developed vaccines for the treatment of some diseases.
2) His swan neck flask experiment helped him irrefutably disprove the theory of spontaneous generation.

Question 14

Why was the bend in the swan neck flask important?

Answer 14

The neck prevented airborne microorganisms from entering the flask and contaminating the broth. This also allowed air from the inside to be exchanged with the outside while keeping the broth sterile.

Question 15

What was the purpose of the flask that had the neck broken off?

Answer 15

It was used as a control to show that when airborne microorganisms have access to the broth in the flask, microbial growth would be seen in the flask.

Question 16

Linneaus

Answer 16

He developed a new way to categorize organisms into different levels based on their similarities.
He also developed the naming system known as binomial nomenclature.

Question 17

How have phylogenetic trees changed since Linnaeus?

Answer 17

More kingdoms were added by other scientists. Haeckel proposed having four kingdoms, adding protists and monera which were for unicellular organisms with a nucleus, and for unicellular organisms that lack a nucleus respectively. After, Whittaker proposed adding a fifth kingdom to the tree of life, fungi, which was considered the standard for years. Later, Woese would create a phylogenetic tree that categorizes organisms based on the similarity of their gene sequences.

Question 18

What is the correct naming of an organism using binomial nomenclature?

Answer 18

A two-word name that classifies an organism by its genus and specific epithet.

• Genus must be capitalized
• Specific epithet is lowercase
• The whole name must be italicized (typing) or underlined (writing)

Question 19

Woese

Answer 19

He created a phylogenetic tree based on the differences and similarities in the small subunit rRNA gene sequences of different organisms.
He discovered a level above kingdoms known as domains (bacteria, eukarya, archaea)

Question 20

What specific sequence allowed Woese to make his significant discovery?

Answer 20

small subunit rRNA gene sequences

Question 21

What was Woese’s significant discovery?

Answer 21

Archaea

Question 22

How have gene phylogenetic trees changed how we think about species?

Answer 22

It helped show that archaea, bacteria, and eukaryotes all evolved from a common ancestral cell type. Instead of thinking in terms of trees of life, we now think in terms of webs of life as scientists discover how closely evolutionarily related organisms are.

Question 23

Redi

Answer 23

He was one of the first scientists to refute the idea of spontaneous generation through his experiment with meat and the appearance of maggots.

Question 24

What is spontaneous generation?

Answer 24

When life can be produced from nonliving matter

Question 25

What is the purpose of the open container in Redi’s experiment?

Answer 25

The open container was used as a control to show that meat left in the open air formed maggots. This helped his experiment by demonstrating that the meat inside closed containers will not form maggots as they are not exposed to open air.

Question 26

Semmelweis

Answer 26

He showed that handwashing was effective at preventing the transmission of diseases.

Question 27

Snow

Answer 27

He fought against the idea that disease was only caused by contaminated air. He demonstrated that contaminated drinking water was the cause of transmission of the cholera bacteria in London.

Question 28

What field did snow develop through his work?

Answer 28

epidemiology

Question 29

Lister

Answer 29

He proved that using carbolic acid as a disinfectant was effective at preventing postsurgical infections. His discovery became standard practice to prevent infections after surgery.

Question 30

Koch

Answer 30

He assigned pathogens to diseases.

Question 31

What are Koch’s 4 postulates?

Answer 31

1. A suspected pathogen should not be found in healthy individuals but must be found in people who have the disease. (association)
2. The suspected pathogen needs to be isolated and grown in pure culture. (isolation)
3. Inject the healthy test subject with the suspected pathogen grown in pure culture. They need to develop the same symptoms of the disease. (causation)
4. Take another sample of the same pathogen from the host and re-isolate it. This shows that the suspected pathogen causes the disease. (reisolation)

Question 32

Will all diseases fit Koch’s postulates?

Answer 32

No

Question 33

What are some examples that won’t fit all 4 postulates?

Answer 33

1) Healthy carriers
2) Organisms that can’t grow in pure culture (viruses, some bacteria)
3) Reinfecting a new host (some diseases have not fulfilled Koch’s postulates)

Question 34

Ehlrich

Answer 34

After screening hundreds of compounds, he discovered compound 606, known as salvarsan, that targeted treponema pallidum, the bacteria that causes syphilis. This was then used to treat the disease in people. His screening method is still used today.

Question 35

Fleming

Answer 35

He discovered the first natural antibiotic, penicillin. Through his research, he found that penicillin effectively fought against and inhibited staphylococcal growth.

Question 36

Jenner

Answer 36

Developed the process of vaccination. He noticed that people who had cowpox did not get infected with smallpox. He used cowpox to protect people from smallpox.

Question 37

What are viruses?

Answer 37

They are acellular microorganisms (not composed of cells, are only made up of proteins and genetic material DNA or RNA)
Can infect all types of cells (responsible for numerous diseases in humans although, many viruses do not cause disease )