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Biosci 3313: Microbiology > Exam 1 > Flashcards

Exam 1 Flashcards

1
Q

What are some ways microorganism affect life?

A

Microbiome in gut, pathogens, foods, digest food, break down toxins, study, model for early life, source of all life, very diverse/abundant, grow everywhere, affect geosphere/climate, symbiotes, industrial - genetic engineering, source of enzymes

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2
Q

Meaning of ATCC

A

American Type Culture Collection

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3
Q

PAMPs and MAMPs

A

Pathogen Associated Molecular Patterns are now referred to as Microbial Associated Molecular Patterns
highlight that microbes can have beneficial or negative roles

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4
Q

Why are vertebrate immune systems more complex than invertebrates? (Margaret McFall-Ngai

A

They have a longer lifespan and have the opportunity and necessity to develop that way

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5
Q

Meaning of LUCA

A

last universal common ancestor

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6
Q

3 Domains of Life

A

bacteria, archaea, eukarya

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7
Q

Conditions on earth during heavy bombardment

A

no water, high temperatures, reduced gases in the environment

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8
Q

What are stromatolites? How old are they? Where are they found?

A

Fossils greater than 3.5 BYA found during the 1950s in intertidal marine areas
Mats of mostly photosynthetic organisms
Some are still found in Australia today

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9
Q

The oldest eukaryotes are __________

A

2.5 MYA

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10
Q

The oldest bacteria are _____________

A

3.5 BYA

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11
Q

The earliest branches of the Tree of Life contain _____________ bacteria

A

thermophilic

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12
Q

When did microbiology as a scientific discipline begin?

A

People began linking specific microbes to disease in the 1800s, partially due to the development of agar plates allowing separation of microbes
In the 1850’s people thought disease was caused by “bad air”

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13
Q

Three Eras of the Science of Microbiology?

A

Pre-Germ Theory, Golden Age, Modern Era

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14
Q

Contribution to Microbiology: Francisco Redi

A

cheesecloth over meat, disprove spontaneous generation

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15
Q

Contribution to Microbiology: Antoni van Leeuwenhoek

A

first microscope, discovered animalcules/microorganisms

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16
Q

Contribution to Microbiology: Edward Jenner

A

cowpox (cowpox victims were immune)

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17
Q

Contribution to Microbiology: Ignaz Semmelweis

A

childbed fever, pregnant women, handwashing

Women who delivered babies in hospitals
died more often

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18
Q

Contribution to Microbiology: John Snow

A

ghost map, cholera, father of epidemiology

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19
Q

Contribution to Microbiology: Louis Pasteur

A

disprove spontaneous generation, swan flask

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20
Q

Contribution to Microbiology: Joseph Lister

A

disinfectant before surgery

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21
Q

Contribution to Microbiology: Robert Koch

A

germ theory, 4 postulates, causative agents of anthrax and tuberculosis

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22
Q

4 Postulates and their purpose

A

Observe, Isolate, Infect, Reisolate

1st (Observe): Make the observation
Pts with tb have a particular microorganism associated with them
2nd (Isolate): Isolate that organism in pure culture
Possible with agar plates
3rd (Infect): Infect an individual with the purified organism
4th (Reisolate): Reisolate the same organism from the infected individual

Demonstrate that a disease is caused by a microorganism

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23
Q

Germ Theory

A

Germ Theory: A disease-causing microorganism should be present in animals infected by the disease and not in healthy animals

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24
Q

Contribution to Microbiology: Fannie Hesse

A

agar plates (instead of gelatin)

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25
Contribution to Microbiology: Hans Christian Gram
gram stain (1st differential stain)
26
Contribution to Microbiology: Sergei Winogradsky
principles of chemolithotrophy, Winogradsky column
27
Contribution to Microbiology: Martinus Beijerink
virus and enrichment techniques
28
Contribution to Microbiology: Beatrix Potter
mycologist
29
Contribution to Microbiology: Paul Ehrlich
chemotherapy (salvarsan)
30
Contribution to Microbiology: AJ Kluyver
comparative biochemistry
31
Contribution to Microbiology: Alexander Fleming, Howard Florey, and Ernst Chain
penicillin, mold that grew on agar petri dish killed bacteria on the same agar
32
Contribution to Microbiology: Alice Evens
pasteurization of milk
33
Contribution to Microbiology: Rebecca Lancefield
serotyping streptococci
34
Contribution to Microbiology: Selman Waksman
streptomycin
35
Contribution to Microbiology: Oswald Avery, Colin MacLeod, Maclyn McCarty
identify deoxyribonucleic acid (DNA) as the "transforming principle" responsible for specific characteristics in bacteria
36
How do microscopes work?
light bends as it passes through substances of different densities
37
Define resolving power
distance between two objects that can be separated by the lens in the formation of an image
38
Better Resolving Power = wavelength, refractive index, angular aperture
shorter wavelength (purple/UV) high refractive index higher angular aperture
39
Describe chromatic aberrations of microscopes
Different wavelengths focus at different places | Due to combining lenses of different shape and composition
40
Describe spherical aberrations of microscopes
Light rays at periphery focus at a different place from the rays at the center
41
Describe a darkfield microscope
dark background, structures of cells stand out
42
Describe a phase-contrast microscope
enhance contrast of cells and their medium Denser objects appear darker (extremely dense is white) More contrasts lends a 3D look
43
What is unique about fluorescence microscopy?
uses dyes and antibodies
44
Describe a confocal scanning microscope and what they are used for
See where cells are in tissues and how they move | Visual cells, 3D structures
45
Describe electron microscopes (general)
very high magnification, only dead organisms, need coating, black and white
46
What is a SEM microscope? How is it used?
Scanning electron microscope | Surface only
47
What is a TEM microscope? How is it used?
Transmission Electron microscope | 3D, thin slice of material, internal structures
48
Describe a Nermaski microscope
Behaves like SEM surface structures 3D appearance
49
Term for rod
bacillus
50
Term for round
coccus
51
Term for short rod (different from rod)
coccobacillus
52
Term for spiral
spirillum
53
Term for curved rod (different from short rod)
vibrio
54
Term for long, loose, helical spiral
spirochete
55
What would you call a joined pair of cocci?
diplococcus
56
What would you call a cube of cocci?
tetrad
57
What would you call a cluster of cocci?
staphylococcus
58
What would you call a chain of rods?
streptobacillus
59
Define inclusions
Structures inside the cell used for storage, detoxification, and movement
60
What is poly-beta-hydroxybutyrate?
a compound used for carbon storage that can be used for biodegradable plastic
61
What is the purpose of gas vesicles?
allow aquatic microorganisms to modify their density
62
What are stains used for?
Increase contrast, distinguish bacteria, see subcellular structures
63
What is the difference between acidic and basic stains?
Basic dyes stain negatively charged membranes, acidic dyes stain the surroundings of negatively charged membranes
64
What is the difference between simple stains and differential stains?
Gram stain is a differential stain, organisms act differentially in differential stains depending on the strain
65
What are specialized stains for?
Detect specific cellular components (such as flagella)
66
What are the four steps of a Gram stain? Which is most important?
1st Primary stain- prepare smear -> Both cells stained purple Take cells and smear with water, then let dry. Crystal violet stain first (stains every bacterial cell) 2nd Mordant- flood preparation Iodine solution that intensifies the purple 3rd Decolorization- add ethanol -> Dye washes off gram-negative 4th Counterstain- stain with safranin To see the gram negative bacteria (which are now clear), add safranin 3rd step is most important, will have controls to test the method
67
What are some functions of prokaryotic surfaces?
Cell-cell contact, non-specific binding, holding shape, cation/anion binding, protection, molecular sieve
68
What are pili/fimbrae?
rods that help bacteria attach to surfaces
69
What is a capsule/slime layer/biofilm? What is it for?
polysaccharide layers outside of the cell wall/membrane (also called glycocalyx) Can help attachment to surfaces, prevent desiccation, or provide protection
70
What are some of the purposes of the cytoplasmic/plasma membrane?
Provide a selective barrier between the cell wall and internal structures Site of photosynthesis (bacteria), DNA replication, and enzyme reactions Small hydrophobic molecules pass through the best
71
Gram-Negative vs Gram-Positive: Peptidoglycan layer
thin in negative, thick in positive
72
Gram-Negative vs Gram-Positive: presence of lipoteichoic acid
absent in negative, present in peptidoglycan wall of positive
73
Gram-Negative vs Gram-Positive: presence of outer (secondary) layer
present in negative, absent in positive (more susceptible to attacks on peptidoglycan wall)
74
Gram-Negative vs Gram-Positive: presence of periplasmic space
present in negative (between 2 membranes), absent in positive
75
Gram-Negative vs Gram-Positive: tetrapeptide chain components
meso-diaminopimelic acid in negative, L-lysine in positive
76
Gram-Negative vs Gram-Positive: linkage between tetrapeptide chains
direct in negative, pentapeptide in positive
77
What are the special components of the outer membrane of gram-negative bacteria?
Outer membrane containing “lipid A”, which is linked by sugar to an O polysaccharide (repeating sequence, varies between cells) Whole thing called a lipopolysaccharide (LPS) Lipid A is toxic
78
What are the sugars that both gram-negative and gram-positive contain in their cell walls?
NAG and NAM
79
What allows packaging of chromosomal DNA?
supercoiling
80
How are archaea different from bacteria (cell wall)?
Many lack a cell wall Never contain peptidoglycan (also called murein) May have pseudomurein or protein cell walls (S-layer)
81
What is the purpose of an endospore?
Formed due to lack of nutrients, toxins, certain types of cell-cell contact, and other types of stress Protects from desiccation, heat, chemicals (including immune system), UV radiation, high refractivity Metabolically inert
82
How are endospores produced?
A special type of asymmetrical reproduction called sporulation Cell begins to reproduce asymmetrically → larger portion “engulfs” smaller portion → cell lyses → free endospore then removes a lot of liquid and produces proteins to make its exosporium, spore coat, core wall, and cortex
83
How can endospores be used in differentiating bacteria?
ability to make one, its size, its location
84
Describe the prokaryotic flagella
pure protein, solid/stable, very long, move by roatation
85
What are the parts of a prokaryotic flagella?
basal body, hook, filament
86
What is the term for a tuft of flagella?
loctricus
87
What is the term for flagella all over?
peritrichous
88
What is the term for two or more polar flagella?
lophotrichous
89
How do bacteria move? (general)
Without any stimulus bacteria will move until they reach equilibrium, stay near favorable areas and leave unfavorable areas, move by either tumbling or running
90
Describe a bacteria "run". How is it used to move bacteria to a better location?
use flagella to move in a specific direction If there is an attractant present they will extend their run and if there is a toxin they will shorten their run
91
Describe a bacteria "tumble". Why do they do that?
throw out their flagella and float randomly they have to keep sensing, bacteria are always trying to sense their environment
92
Describe a hemocytometer or a petroff-hausser slide
A special slide designed for counting the bacterial cells in a measured volume of sample Easy to use, fast, inexpensive
93
What are the limitations of cell counting via hemocytometer?
Cannot distinguish live/dead, overlook small cells, imprecise (esp. low densities)
94
How does a coulter counter work? What are its limitations?
Counts cells by measuring change in resistance in a solution when a cell passes through a small opening Rapid and accurate up to certain concentrations Does not differentiate between live/dead cells
95
Describe the spread-plate method
Sample is pipetted onto agar and spread
96
Describe the pour-plate method
Sample is pipetted into plate, then medium is added Volumes greater than .1 mL
97
What range of cells can be reliably counted?
30-300 cells/colonies, units are CFU/mL
98
What are the advantages and disadvantages of plate counting?
most accurate method (slightly low), but it requires a lot of plates, time, and effort
99
How are cells counted with a spectrophotometer?
Measured with a spectrophotometer with units as OD600 Rapid, can measure change over time easily, need a minimum concentration of cells As long as above min, equally accurate at low + midrange Usually plotted on a semi-log scale
100
Define growth
Increase in microbial mass indicates a change in the number of cells in a given locale
101
What is the equation to determine the number of generations needed to reach a certain population size?
Nn = N0 * 2^n Nn is the number of cells at any generation n N0 is the initial number of cells n is the number of generations
102
What are the four phases of bacterial growth?
lag, exponential/lag, stationary, death
103
Describe the lag phase of cell growth
no cell division Cells grow larger and are metabolically active, synthesizing proteins and making repairs
104
Describe the exponential/log phase of cell growth
generation time constant Used for experiments to determine growth rate in prime conditions
105
Describe the stationary phase of cell growth
reproduction/death balanced May have more cells (than exp/log), but many will be dead Amount of viable cells remain the same
106
Describe the death phase of cell growth
death exceeds reproduction exponentially
107
Describe rich/complex media
Not all ingredients defined (yeast extract, peptone, tryptone), supports growth of a wide range of bacteria
108
Describe enriched media
contains added essential nutrients specific organisms need to grow
109
Describe enrichment cultures
preferred growth of desired microorganism followed by growth in selective media
110
Describe fastidious organisms
cannot make certain nutrients and require them to be added to their media
111
Describe chemically defined media
Identity/quantity of all contents known Supports growth of fewer numbers of bacteria Types dependent on carbon source
112
Describe selective media
Discourages the growth of specific types of organisms | Usually contains ingredients such as antibiotics, dyes, detergents, or salts
113
Define streak plating
procedure that uses inoculating loops to isolate a pure culture of a bacterium from a mixture
114
Describe differential media
Certain organisms will acquire a specific appearance | Usually contains pH indicator dyes or cleaveable color-changing substrates

Biosci 3313: Microbiology (4 decks)

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