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Microbiology > Microbiology Exam 2 > Flashcards

Microbiology Exam 2 Flashcards

1
Q

What are the two key principles of microbial ecology

A
  1. Every molecule existing in nature can be used as a source of carbon or energy by a microorganism found somewhere in the biosphere.
  2. Microbes are found in every environmental on Earth
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2
Q

What is assimilation

A

process by which organisms acquire an element, such as carbon from CO2, to build cells

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3
Q

What is dissimilation

A

the process of breaking down organic nutrients to inorganic minerals such as CO2 and NO2-, usually through oxidation.

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4
Q

What is biomass

A

the bodies of living organisms

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5
Q

food webs depict what?

A

the way in which various organisms consume each other, and products

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6
Q

trophic levels

A

levels of consumption

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7
Q

How much biomass is lost between trophic levels?

A

10%

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8
Q

Every food web depends on primary producers for what two things?

A

absorbing energy from outside ecosystems, assimilating minerals into biomass

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9
Q

consumers

A

acquire nutrients from producers

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10
Q

grazers

A

first level consumers that feed on producers

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11
Q

predators

A

level of consumers that feed on grazers

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12
Q

decomposers

A

returning carbon and minerals back to the environment for use by producers

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13
Q

detritus

A

discarded biomass such as leaves and stems that require decomposition

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14
Q

In aerobic conditions what acts as an electron acceptor?

A

molecular oxygen

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15
Q

in anaerobic conditions what acts as an electron acceptor?

A

Fe3+, and NO2-

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16
Q

What types of microbe are found in acidic environments at or below pH3

A

acidophiles

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17
Q

What types of microbe are found in pH environments 9-14

A

alkaliphile

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18
Q

What types of microbe are found in high pressure (200-1000atm)?

A

Barophile

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19
Q

What types of microbe are found in high salt (2M)

A

Halophile

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20
Q

What types of microbe are found in extreme high temperatures (above 80C)

A

hyperthermophile

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21
Q

What types of microbe are found in low temperature (below 15C)

A

psychrophile

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22
Q

What types of microbe are found in moderately high temperature (50-80C)

A

thermophile

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23
Q

two orgainsms grow in intimate species-specific relationship in which both partner species benefit

A

mutualism

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24
Q

One species benefits while the other partner species neither benefits nor is harmed

A

commensalism

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25
Q

Relationship where one species benefits at the expense of the other

A

parasitism

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26
Q

a metabolic association between two species, requiring both partners in order to complete the metabolism

A

syntrophy

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27
Q

Grazers make up how much of the biomass formed?

A

10%

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28
Q

First level predators make up how much of the biomass formed?

A

1%

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29
Q

Second level predators make up how much of the biomass formed

A

0.1%

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30
Q

Microbes are decomposers and are responsible for what?

A

responsible for biotic breakdown or organic material
recycling biomass through varied metabolic routes
dependent on abiotic environmental conditions

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31
Q

microbes are dependent upon what environmental conditions?

A

O2 availability, enzyme activity

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32
Q

What is biogeochemical cycling?

A

microbes use their collective metabolism to convert chemical elements into various compounds

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33
Q

CO2 can become what 2 products in the carbon cycle?

A

fixed into organic biomass (CH2O) or reduced to methane (CH4)

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34
Q

What is succession?

A

organism 1 creates metabolites that organism 2 will use to thrive

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35
Q

Microbes on the marine floor are what in terms of the carbon cycle?

A

decomposers that aid producers

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36
Q

Hypoxia occurs in what type of circumstances?

A

Increased aerobic microbial growth, consumng the O2 in the water

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37
Q

What are the consequences of marine hypoxia?

A

no dissolved O2 due to the aerobes using all the dissolved O2 in the water, fish are not able to live here any longer and they move to other locations.

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38
Q

What to we know about the microbes used in oil spill clean up?

A

Aerobes, that degrade aromatic or saturated hydrocarbons,

Often psychrophiles, use enzymes at low temperatures

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39
Q

Effects on methane levels when using microbes for oil spill cleanup?

A

oil/hydrocarbon degrading yields methane
Creates nutrients for methanotrophs
diversifies food web as consumers feed
Moves carbon into new species and locations in carbon cycle

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40
Q

What is nitrogen fixation?

A

N2 going to NH4+

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41
Q

What is nitrification?

A

oxidation of ammonia to nitrate (NO2-) or nitrate (NO3-)

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42
Q

What is denitrification?

A

Nitrite/nitrate back to N2/NH4+

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43
Q

Where is nitrogen found biologically

A

In nucleic acids. You can’t make nucleic acids from gas N2, but rather from eating other organisms amino acids.

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44
Q

What is a microbe that does nitrogen fixation?

A

Clostridium (endospore former and strict anaerobe)

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45
Q

What microbes do nitrification?

A

Nitrosomonas, Nitrobacter, Nitrospira

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46
Q

What microbes do denitrification?

A

Proteobacteria, Sulfurimonas, denitrofication

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47
Q

What is the microenvironment around a plant root?

A

mycorrhizae

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48
Q

What are the fungi that gather outside the root but never invade?

A

ectomycorrhizae

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49
Q

What are the projections that extend outside the root to absorb and metabolize the soil

A

fungal hyphae

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50
Q

What is the microbe that assists plants in nitrogen fixation?

A

Rhizobia

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51
Q

How does a plant acquire Rhizobia?

A

Nod flavonoid proteins (chemoactrant)

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52
Q

Rhizobia does what when taking up residence in the root?

A

Release factors to promote root growth
Moves in and around the cells of the root
Form nitrogen-fixing bacteroids in nodules

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53
Q

What is the name of fungi that penetrate into the root cells?

A

endomycorrhizae

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54
Q

What is the microbe that lives in the gut of termites?

A

Mixotricha paradoxa (protist)

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55
Q

Describe microbial succession

A

Microbes competing for nutrients/ resources
Microbes attacking competitors
Some microbes taking advantage of the metabolic activities of others, moving into environments after pioneers

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56
Q

What are the steps in biofilm formation?

A
  1. attachment monolayer
  2. microcolonies
  3. exopolysaccharide (EPS) production
  4. Mature biofilm
  5. dissolution and dispersal
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57
Q

What is quorum sensing?

A

the ability to tell how many other microbes are around.

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58
Q

describe the microbial succession of microbes in a closed system of milk.

A
  1. Lactococcus lactis converts all the lactose to lactic acid
  2. lactobacillus sp. works to slowly ferment the lactose, only after the initial pH change
  3. Yeasts and molds, buffer the solution by breaking down non sugar substances
  4. Putrefying bacteria, stripping off the amino acids, some containing sulfur, they wait for all other competition to go away.
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59
Q

What did Sergei Winogradsky do/ when did he live?

A

1856-1953, water-column model, studied interactions, rather than isolated species

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60
Q

What type of bacteria is found at the top of a water column?

A

Cyanobacteria

61
Q

Describe the layers of microbes found at the bottom of the water column.

A

Purple Sulfur Bacteria first, then Green sulfur bacteria, followed by sulfate-reducing bacteria on the bottom

62
Q

Compare and contrast the differences between the top and bottom of the water column.

A

Top: oxygen is the highest and the sunlight is full spectrum
Lower: very low oxygen, only specific light photons, carbon rich

63
Q

What is the role of the green sulfur bacteria?

A

produce sulfur gas that bubbles up to the purple bacteria where it is interacted with

64
Q

What are the 3 temperature levels in an aquatic environment?

A

Epilimnion, Thermocline, Hypolimnion

65
Q

How does an aquatic environment vary with depth?

A

Available photons, Oxygen concentration, Temperature, Hydrogen sulfide concentration

66
Q

What types of environmental factors impact microbes?

A

Water composition based on location, seasonal ditritis and temperature changes, run-off with nutrients (Mississippi River with fertilizer example)

67
Q

What types of microbes are found on the ocean floor around a thermal vent?

A

thermophiles, psycrophiles (farther out), halophiles, barophiles (pressure)

68
Q

Describe the type of environment around a thermal vent.

A

Rich, very diverse, open environment

69
Q

Describe the type of environment on the ocean floor

A

Very specific environment

70
Q

What is BOD? What does it stand for?

A

Biochemical oxygen demand, potential for aerobic metabolism.

71
Q

Why does sewage have to be processed?

A

To reduce the BOD level to prevent nutrient runoff into a water source

72
Q

What does the addition of nutrients to the environment due to the microbes there.

A

It increases the number and ability of aerobic microbes to metabolize, consuming dissolved O2 and creating a hypoxia condition

73
Q

What are the steps on wastewater treatment?

A

Preliminary: remove solid debris
Primary: sediments insoluble material
Secondary: use aerobic metabolism to remove organic material (reduce BOD, biofilms form on sediment)
Tertiary: anaerobic digestion of mineral compounds, then treated with volatile chlorine to sanitize

74
Q

Describe the steps in composting.

A

Early Stage: aerobic decomposers eat away polysaccharide and cellulose rich materials raising temperature to 50-60C
Late Stage: thermophillic microbes take over

75
Q

What is a thermophillic microbe used in composting?

A

Alicyclobacillus (gram-)

76
Q

What is a consequence of bioremediation?

A

Microbes cannot metabolize and degrade all of the toxic material. (2,4-D example)

77
Q

Bioremediation can be used to manipulate microbes through biostimulation in which 2 ways?

A

Adding nutrients to already present microbes allowing outgrown to deal with toxins
Brining in a new microbe that wasn’t normally present in the population to degrade a toxin that is found there.

In both cases the extra microbes die off after the toxin food source is depleted.

78
Q

Who is John Snow/ what did he do?

A

Barely the Golden Age, Worked in medical clinics and believe in germ theory. Famous for examining maps during London’s cholera outbreaks to predict the source of the disease.

79
Q

With a cholera infection how much water do you loose a day?

A

20L, patients die from altered BP due to dehydration most of the time.

80
Q

Why was there such a large cholera outbreak in London?

A

Industrial age where waste was going from the pipes into the river or underground and contaminating the well drinking water.

81
Q

What are the principles of epidemology?

A

Factors influencing the frequency and distribution of disease
Inter-disiplinar thinking/ approach (ecology, sociology, stats, and psychology)
Knowing factors allows for development of control strategies and relative concern

82
Q

What is an endemic disease

A

always present in the population but at a low rate. (normal flu)

83
Q

What is an epidemic disease

A

frequency is much higher than normal (whooping cough)

84
Q

What is a pandemic disease

A

disease spans contents (if whooping cough went to China)

85
Q

What is a disease

A

when you have a (microbe, substance) that causes you to loose or have impaired function

86
Q

Describe the relationship between a disease agent, environment, and the host

A

An equal interaction (remember triangle model)

87
Q

To understand infectious disease you must know what?

A

Agents of diseases, reservoirs of microbes, and routes of transmission

88
Q

What are the factors that influence the outcome of an infectious event?

A

Dose (number of microbes you encounter)
Disease agent characteristics (varied potential to infect)
Population (At risk population, susibillity)

89
Q

Who is an “at risk” population?

A

Weak immune status patients (old age, poor nutrition, non-vaccinated, genetics)
Hazardous social practices (drugs, unprotected sex)

90
Q

What are reservoirs?

A

places where microbes are commonly found

91
Q

What are the types of reservoirs?

A

Asymptomatic carriers
Zoonotic carriers
Environmental reservoirs

92
Q

What are asymptomatic carriers?

A

looks healthy but shedding microbe to infect

93
Q

What are zoonotic carriers?

A

Different species can harbor the disease, perhaps without symptoms (salmonella, campylobacter)

94
Q

What are environmental reservoirs?

A

Microbes that are found naturally outside the host (bacillus anthracis, clostridium tetani)

95
Q

What are the types of transmission routes?

A

Fecal-oral
urogenital
Airborne (Person-to-person, and Airborne microbes)
Direct contact

96
Q

Describe the fecal oral transmission route

A

usually via hands or inanimate objects

97
Q

describe the urogenital transmission route

A

direct sexual contact, STI’s (not very hardy will fall apart very easily

98
Q

Describe the Airborne, Person-to-person transmission route

A

Aerosolized by carrier, inhaled by uninfected person (rhinovirus, influenza)

99
Q

Describe the airborne microbes transmission route

A

can be aerosolized mechanically (hantavirus)

100
Q

What are the direct contact transmission routes?

A

Fomites, skin-to-skin, vectors (mechanical or biological)

101
Q

Describe the fomite transmission route

A

Inanimate objects that transfer microbes (cutting board for Camplyobacter)

102
Q

Describe the skin-to-skin transmission route

A

Direct contact (hand shake)

103
Q

Describe the mechanical vector transmission route.

A

Transport via live source, but microbe’s life cycle does not include this source

104
Q

Describe the biological vector transmission route

A

Microbes life cycle includes the biological vector, often a bitting insect (mosquito in malaria, Versinia pestis in rat fleas)

105
Q

What are the ways in which you can get Bacillus anthracis?

A

Cutaneous- skin infection curable
GI- ulceration and necrosis of intestines (most often fatal)
Inhalation- rapid lung damage, blood infection, cardinal cap (is fatal)

106
Q

In the bubonic plague (Yersinia pestis) humans are what?

A

Incidental hosts which can secondarily contract pneumonia plague and transmit that person-to-person.

107
Q

Why is it hard for people to transmit Yersinia pestis (plague)?

A

The microbe is contained in the lymph fluid and the fleas that transmit the bacteria are drawing from the blood supply.

108
Q

What are the steps in managing infectious diseases?

A

Detection
Treatment
Prevention

109
Q

What are the steps in detecting infectious diseases?

A

Onsite reporting
Genetic tests
Information management

110
Q

What are the steps in treating a population for infectious disease?

A

Onsite diagnosis
Knowing Disease characteristics
Preparedness for delivery

111
Q

What are the prevention steps in managing infectious disease?

A

Risk assessment
Cost effectiveness
Behavior modification

112
Q

What are the types of epidemiological data?

A

Descriptive
Analytical
Experimental

113
Q

Describe descriptive epidemiological data

A

After infection:who what where (just facts)

114
Q

What are the types of analytical data?

A

Cross-sectional: subgroups
Retrospective: analysis of disease characteristics
Prospective: analysis follows groups over time

115
Q

Describe experimental data

A

This is the only way to test hypotheses about infectious diseases
Treatment vs control groups
Most often double blind study to avoid bias

116
Q

How many microbes are pathogenic?

A

1/20

117
Q

What are some anatomical barriers of hosts that house microbes?

A

Skin: has gram+ staphylococcus
Mouth: diverse mixtures of species
Gut: many microbes aid digestion, including gram- microaerophiles (helicobacter) and gram+ fermenters

118
Q

Being infected means what?

A

An established state that isn’t changing, not necessarily bad. You can be infected without loosing function (e. Coli in gut)

119
Q

Disease means what?

A

An established state in which you do loose function

120
Q

What are primary or frank bacteria?

A

Cause disease in healthy, immuno-competent hosts

Usually have virulence factors

121
Q

What are opportunistic infections

A

Only infect immuno-compromised patients

122
Q

How can you become immuno-suppressed?

A 
Older people
Malnourished 
Work in harmful environments 
Other diseases 
Bad social practices 
Genetics
123
Q

What is an acute infection?

A

Infection builds
Hits peak
Immune system fights it off
(Short time infection: Rhinovirus)

124
Q

What is a chronic infection?

A

Infection builds
Hits a peak and persists through life of host
(Hepatitis- has many virulence factors to hide from the host immune system)

125
Q

What is a latent infection

A

Infection builds
Hits a peak
Body fights it almost all the way until the disease is pushed into hiding
(Varicella virus. When your immune system isn’t as strong to keep the virus in hiding then it erupts and causes disease)

126
Q

What is a localize infection

A

Only in one area, not in the blood

127
Q

What is a bacteremia?

A

Bacteria in the blood; cureable

128
Q

What is toxemia?

A

Bacterial products (toxins) in the blood

129
Q

What is septicemia?

A

Bacteria and toxins in the blood, often lethal

130
Q

What does a microbe use to adhere to the host cells?

A

Adhesins, as virulence factors (e Coli use this) (EPEC)

Other adhesins can be used, but must be on the cell surface

131
Q

What is colonization?

A

Happens in an established infection
Cell division and survival
Establishment while fighting the immune system

132
Q

How does cholera toxin work?

A

The toxin is brought into the cell through endocytosis, taken to the ER where the subunits break apart, the subunit binds to the cAMP g-protein up regulating the cAMP production, causing increased release in cellular ions, while water follows

133
Q

Exotoxins do what?

A

Subvert host cells,
Forces advantageous response aiding the microbe
Can diminish host responses

134
Q

Why would a microbe want to burst a RBC?

A

The busting (hemolysis) releases Fe from the RBC and the microbe takes it as it is needed for enzymatic activity

135
Q

What type of exotoxins does cholera toxin have?

A

A-B toxin

136
Q

What type of exotoxins does salmonella typhimurium have?

A

Type III

137
Q

How does type III exotoxin work?

A

After endocytosis the A1 subunit “locks” g-factor on leading to an over production of cAMP, cAMP opens ion channels to pump ions into the gut. Type III structures inject toxins into the host cell

138
Q

How does a host cell respond to type III exotoxin injecting effector proteins?

A

Responds by membrane ruffling where the cell will incase the microbe

139
Q

How does salmonella survive in the host?

A

Virulence factors for evading the immune system
Avoid white blood cells by :
Moving cell to cell
If capture escape and block the white blood cell and use the cell as camouflage

140
Q

Describe the alternate camouflage strategy.

A

Disguise surface by altering the structure on the surface of the microbe to fool the immune system

141
Q

What common virus use the alternate camouflage strategy?

A

Rhinovirus
Influenza
HIV/aids

142
Q

Saprophytes gain nutrients from what?

A

Dying skin cells

143
Q

How would you describe the shape of fungi?

A

Dimorphic: spores and other forms

144
Q

What are dermatophytes?

A

Cause skin infections (invasion)

145
Q

Name two fungal dermatophytes

A 
Ringworm (microsporum) 
Athletes foot (tricophyton)
146
Q

What is candida albians? And who does it infect?

A

Thrush- a yeast infection
Invades immuno-compromised patients
This is a constant state disease, not a common transient yeast infection.

147
Q

Plasmodium sp. does what

A

Common cause of malaria

Lyses RBCs causin anemia and clots

148
Q

Describe the malaria life cycle

A

Sporozites injected into human
Sporozites travel to liver cells by blood
Sporozites undergo schizogony into merozoites and lyse liver cells
Merozoites invade RBCs undergoing schizogony and bursting RBCs
Gametes formed and picked up by mosquito
Fertilization occurs in mosquito
Sporogomy happens in mosquito midgut, sporozoites lyse gut cell and travel to saliva gland

Microbiology (4 decks)

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