Exam 1 Lecture 1/2 Flashcards

(42 cards)

1
Q

Which microbes are most related to each other?

A

Archaea and Eukarya

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2
Q

What is the typical size of a microbe?

A

Less than 1mm

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3
Q

Definition of a microbe

A

A living organism that requires a microscope to be seen

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4
Q

Prokaryotes

A

Bacteria and Archaea

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5
Q

Eukaryotes

A

Algae, fungi, protozoa

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6
Q

Virus (attributes from lecture 1)

A

Acellular, lack many hallmarks of living organisms

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7
Q

True or False: A microscope can ALWAYS be used to determine if a species is Prokaryotic

A

False

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8
Q

Stromatolites

A

-date back 3.4 billion years ago - microbial mats of cyanobacteria, grew into thick masses of biofilm - covered shallow seas all over Earth

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9
Q

Modern stromatolites

A
  • distinct communities of different bacteria - high salinity excludes predators
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10
Q

Is a stromatolite a microfossil or bio signature?

A

Microfossil

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11
Q

What is a bio signature?

A

chemical and physical signs that could only ave been formed by life - microfossil is a type of bio signature

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12
Q

Robert Hooke

A

1665 –> discovered “cells” under microscope - did not observe bacteria

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13
Q

Antonie van Leeuwenhoek

A

1676 –> observed microbes under microscope

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14
Q

Wendell Stanley

A

purified the first virus in 1899

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15
Q

Alexander Fleming

A

identified penicillin as the first successful antibiotic in 1929 - penicillin molecule isolated in 1941

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16
Q

When was the first genome sequence?

A

1995, first genome sequence of bacterium H. influenzas

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17
Q

What is spontaneous generation?

A

living creatures could arise spontaneously, without parental organisms

18
Q

Lazzaro Spallanzani

A
  • observed cell fission, 1 bacterium split into 2 - showed that sealed flask of boiled meat broth did not have microbes - 1760’s
19
Q

Louis Pasteur

A

Swan-necked flask experiment (1864)

20
Q

Why was the swan-necked flask important?

A

It disproved the idea that Spallanzani’s experiment only worked because the flask was sealed, and they thought microbes didn’t grow because there was no oxygen. However, the swan-necked flask allowed the flask to be open to allow air to come in but microbes still didn’t grow. Only when the flask was tiled after a long time, microbes quickly multiplied

21
Q

What did Lazzaro Spallanzani contribute to microbiology?

A

Helped disprove the spontaneous generation theory

22
Q

What did Louis Pasteur contribute to microbiology?

A

Helped disprove spontaneous generation theory

23
Q

John Tyndall

A

Discovered that spores need to be killed with repeated cycles of boiling

24
Q

What did John Tyndall contribute to microbiology?

A

Contributed to disproving spontaneous generation

25
Autoclave
Machine that uses heat and pressure to kill microbes
26
Germ Theory of Disease
The theory that microbes cause disease
27
"Miasma theory"
The idea that "bad air" caused illness
28
John Snow
Father of Epidemiology Documented cases of cholera outbreak that he used to determine where the outbreak started Common water pump was shown to be the cause
29
Robert Koch's Postulates
1884 1. Microbe found in all cases of the disease but is absent from healthy individuals 2. Microbe is isolated from the diseased host and grown in pure culture 3. When the microbe is introduced to a healthy, susceptible host, the same disease occurs 4. Same strain of microbe is obtained from newly diseased host
30
Exceptions to Koch's Postulates
1. Requires pure culture 2. Requires symptoms 3. Must be able to detect pathogen 4. Requires animal host with the same disease
31
Three Domains of Life
Bacteria, Archaea, Eukarya
32
Binomial system of nomenclature
Genus and species. All italicized, Genus is capitalized and the rest lowercase
33
How similar must 2 species be to be considered of the same species?
At least 95% genetic similarity
34
Carolus Linnaeus
Added animals and plants to categorize, 1758
35
Ernst Haeckel
Added protists and Monera to existing tree
36
Robert Whittaker
Added Fungi as a 5th kingdom
37
Carl Woese contribution
Used 16S rRNA to reveal divergence of domains of life
38
What is the idea behind using 16S rRNA?
Used 16S rRNA as a "molecular clock" Idea: If life arises from one common ancestor, this sequence must have slowly mutated over time to give rise to differences in the sequence - divergent regions as well as conserved regions - sequence divergence can be used as a proxy of genetic relatedness
39
Endosymbiotic Theory
one partner population grows within the body of another organism
40
Characteristics of all living organisms
1. Double stranded DNA 2. Common ancestral RNA polymerase 3. Nearly universal genetic code 4. Common ancestral functional domains 5. Aqueous cell compartment enclosed by a membrane
41
What provides membrane stability to bacteria?
Hopanoids
42
What makes archaea membrane lipids different?
L-glycerol diethers at top, Ether links between fatty acids and glycerol Isoprenoid chains and cross-linked lipids The inside layer can be linked to the external layer- making a monolayer Allows them to withstand extremes