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Microbiology for Nursing > 9.1, 9.2-9.5, 13.2 > Flashcards

9.1, 9.2-9.5, 13.2 Flashcards

1
Q

What is the most common form of bacterial reproduction?

A

Binary Fission

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2
Q

What are the 4 steps of Binary Fission?

A
  1. Growth of cell size and increase in cell components
  2. Replication of DNA
  3. Division of cytoplasm (cytokinesis)
  4. Septum formation and division of daughter cells
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3
Q

What is cytokineses direct by?

A

FtsZ protein

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4
Q

What assembles to form divisome?

A

FtsZ assembles Z ring to form divisome

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5
Q

What does a divisome do?

A

Activates production of peptidoglycan and septum

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6
Q

What does is the term called when referring to the time it takes to double population?

A

Generation Time (Doubling Time)

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7
Q

How long is the generation time for E. Coli?

A

20 minutes

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8
Q

How long is the generation time for B. subtilis?

A

120 minutes

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9
Q

What is the generation time for S. Aureus?

A

30 minutes

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10
Q

What is the generation time for M. Tuberculosis?

A

15-20 hours

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11
Q

What is this equation used for?
Nn= N02^n

A

Calculating the population size

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12
Q

What does the Nn represent in Nn= N02^n?

A

Number of cells at generation n

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13
Q

What does N0 represent in Nn= N02^n?

A

Initial number of cells

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14
Q

What does ^n represent in Nn= N02^n?

A

number of generations

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15
Q

What is culture density?

A

of cells/unit vol.

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16
Q

Which step of the growth curve has the inoculum cells added and adjust to culture medium; no change in population?

A

1st step: Lag phase

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17
Q

Which step of the growth curve has binary fission occurring; cell replication > cell death

A

2nd step: Log (exponential) phase

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18
Q

Which step of the growth curve has resources becoming depleted; cell replication = cell death

A

Step 3: Stationary phase

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19
Q

Which step of the growth curve has endospores forming; cell replication < cell death

A

Step 4: Death Phase

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20
Q

What occurs during Lag phase?

A
  • Cells grows larger; metabolically active
  • Damaged or shocked cells undergo repair
  • Initial cell numbers do not change
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21
Q

What are some factors that determines the duration of the lag phase?

A

Genetic make-up
Media composition
Initial inoculum size

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22
Q

How is generation time determined?

A

Genetically determined; intrinsic growth rate

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23
Q

_____ vs____ is exponential

A

Time vs # of cells is exponential

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24
Q

At what point of the growth curve are the microbes most susceptible to disinfectants and antibiotics that affect protein, DNA, and cell-wall synthesis?

A

Log (exponential phase)
- this is because they are more focused in growing/expanding rather than repairing

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25
Q

What happens during log phase?

A

Constant growth and uniform metabolism

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26
Q

What happens during stationary phase?

A

Waste accumulates; nutrients gradually used up
Culture density is constant
Undergo sporulation

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27
Q

At which point of the growth curve do cells’ synthesis slows; less susceptible to antibiotics; expression of virulence factors and secondary metabolites?

A

Stationary phase

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28
Q

At which phase of the growth curve has toxic waste accumulating; nutrients exhausted

A

Death Phase

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29
Q

Why and when do cells lyse and release nutrients

A

During death phase; to help surviving cells and endospore-formers

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30
Q

What are surviving cells with slow metabolism called? What are some characteristics of them?

A

Persisters
Chronic infections (tuberculosis) and antibiotic resistance

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31
Q

What type of system culture has infinite resources; nutrients and air are replenished; dead cells and waste are removed? What is an example of this system?

A

Open system cultures
Chemostat

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32
Q

What method of quantifying populations size has cells counted under a microscope?

A

Direct microscopic cell count

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33
Q

What is a flaw when using direct microscopic cell count?

A

It cannot distinguish live vs dead

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34
Q

When using the direct microscopic cell count method, what is the calibrated slide where we put our known volume called?

A

Petroff-Hausser chamber

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35
Q

What method of quantifying populations size has cells counted under a microscope or flow cytometer and has a red stain bind to damage cells for indication?

A

Fluorescence Staining

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36
Q

What method of quantifying population size detects electrical resistance change due to cell density (as fluid that contains particles/cells is drawn through the micro-channels, each particle causes a brief change to the electrical resistance of the liquid?

A

Coulter counter

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37
Q

Is there a flaw when using Coulter counter?

A

Yes, it doesn’t differentiate live/dead

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38
Q

What method of quantifying populations size is a count of viable cells; samples are diluted and grown on solid media

A

Viable Plate counts

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39
Q

How are the results of viable plate counts expressed?

A

Colony forming units per volume (CFU/ml)

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40
Q

What is the countable range in a viable plate count? What is it when it’s TFTC and TNTC?

A

30-300 CFU/ml
<30 - TFTC (too few to count)
>300 - TNTC (too numerous to count)

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41
Q

What method is used to measure growth when the sample is very dilute and may not contain enough microbes for plate count?

A

Membrane filtration technique

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42
Q

What does the membrane filtration technique do?

A

Known vol. filtered through a membrane; membrane plated and colonies counted

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43
Q

What does most probable number (MPN) mean?

A

Statistical method used when counts are very low ( <30 CFU/ml)

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44
Q

What happens during the method of MPN?

A

Uses 3 log dilutions grown in 3-5 replicates
Growth is determined positive or negative
Pattern is compared to reference table

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45
Q

What is turbidity?

A

optical density (describes a material’s ability to absorb the power of a given light)

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46
Q

What is turbidity measured with?

A

Spectrophotometer

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47
Q

What happens within a spectrophotometer?

A

Light is passed thru culture and measured on other side

48
Q

turbidity increase = ?

A

Population increase

49
Q

What microbe divides asymmetrically (budding)?

A

Planctomycetes: Gemmata obscuriglobus

50
Q

What microbe divides via fragmentation?

A

Cyanobacteria

51
Q

What is secreted by organisms in the biofilm?

A

EPS- extracellular polymeric substances

52
Q

What is EPS (extracellular polymeric substances)?

A

Hydrated polysaccharide gel with other macromolecules and channels

53
Q

How is biofilm formed?

A

Through quorum sensing (cell to cell communication)

54
Q

Quorum sensing can cause what?

A

Cell density or cellular stress

55
Q

What is it called when small molecules are produced to induce various actions?

A

Autoinducer

56
Q

What autoinducer class are found in gram -

A

N-acylated homoserine lactones

57
Q

What autoinducer class are found in gram +

A

Various short peptides

58
Q

What is an example of beneficial biofilm?

A

Normal biota in lungs

59
Q

What is an example of harmful biota?

A

Plaque formation on teeth

60
Q

How does biofilms provide resistance to antibiotics?

A
  • Cells in deep laters may be metabolically inactive
  • EPS may slow diffusion of biocidal agents
  • Provide optimal environment for sharing of plasmids
61
Q

What main factors affect growth?

A

Oxygen level, pH, temp, osmotic pressure, barometric pressure

62
Q

What’s a low percentage agar tube that has a gradient of oxygen called?

A

Fluid Thioglycolate Medium (FTM)

63
Q

What is determined by location of growth in a FTM?

A

Aerotolerance

64
Q

If growth is found more on the top of the FTM, what is it labeled as based on their oxygen requirement?

A

Obligate aerobes

65
Q

If growth is found more at the very bottom of the FTM, what is it labeled as based on their oxygen requirement?

A

Obligate anaerobes

66
Q

If growth is found mainly on the top, but also scattered throughout the FTM, what is it labeled as based on their oxygen requirement?

A

Facultative anaerobes

67
Q

If growth is found throughout the FTM randomly, what is it labeled as based on their oxygen requirement?

A

Aerotolerant anaerobes

68
Q

If growth is found almost at the top of the FTM, what is it labeled as based on their oxygen requirement?

A

Microaerophiles

69
Q

Which macromolecule is most vulnerable to the changes of pH

A

Proteins

70
Q

What are fermenters mostly adapted to regarding to pH?

A

Acidity

71
Q

What range of pH are neutrophils at?

A

~7

72
Q

What range of pH are acidophiles at?

A

pH<5.5

73
Q

What range of pH are alkaliphiles at?

A

pH 8-10.5

74
Q

What temp are mesophiles usually found in?

A

20-45 C

75
Q

What temp are psychotrophs found in?

A

4-20 C

76
Q

What temp are Psychrophiles found in?

A

<0 C

77
Q

What temp are thermophiles found in?

A

50-80 C

78
Q

What temp are hyperthermophiles found in?

A

80-110; some survive @ >121 C

79
Q

What are salt/solute lovers called and where are they usually found?

A

Halophiles; oceans

80
Q

What are high salt tolerators called and where are they found?

A

Halotolerant; salt marshes where high solutes aren’t present all the time

81
Q

What does barometric pressure mean?

A

Ability to withstand great pressure

82
Q

What are barophiles?

A

Microbes that require high atmospheric pressure

83
Q

Where are barophiles found?

A

Bottom of ocean

84
Q

Because Barophiles could be found in the bottom of the ocean, what type of temp microbes could they be?

A

Thermo or hyperthermophiles

85
Q

What are cyanobacteria and green sulfurs classified as?

A

Photoautotrophs

86
Q

What are purple nonsulfurs classified as?

A

Photoheterotrophs

87
Q

What does PAR stand for and what light spectrum are they usually within?

A

photosynthetically active radiation; visible light spectrum (400-700nm)

88
Q

What is the oldest and most common form of physical means of control of microbes?

A

Heat sterilization

89
Q

What does heat sterilization do?

A

Alters membranes and/or denatures proteins

90
Q

What is “lowest temp that will kill in 10 min” called?

A

Thermal Death Point

91
Q

What is “length of time to kill at a certain temperature” called?

A

Thermal Death Time

92
Q

At what temperature des dry heat occur?

A

> 250C

93
Q

What is it called when there is direct application of high heat; also known as incineration?

A

Dry Heat

94
Q

What is called when there is an application of high temperature liquid/vapor?

A

Moist heat

95
Q

What makes moist heat more beneficial than dry heat?

A

Moist heat penetrates cells better than dry

96
Q

At what temperature and pressure does an autoclave have to reach?

A

~121C and 15 psi

97
Q

What are the 2 types of autoclaves and how does it work?

A

Gravity-uses steam to push out air
Prevacuum- vacuums out air first

98
Q

T/F Autoclaves require periodic quality controls (QC) to check for functionality

A

True, autoclave tape, spore tests, Diack tubes, and recorders are used for QC

99
Q

What type of Heat sterilization semi-sterilizes the food but does not ruin food quality?

A

Pasteurization

100
Q

What temperature and time does HTST pasteurization need?

A

Milk is heated at 72C for 15 seconds

101
Q

At what temperature and time does UHT pasteurization need?

A

138 C for 2 or more seconds

102
Q

What 8 milk borne organisms are killed by pasteurization?

A

Campylobacter jejuni, Coxiella burnetii, Listeria monocytogenes, E. Coli O157:H7, Mycobacterium tuberculosis, M. Paratuberculosis, Salmonella spp., Yersinia enterocolitica

103
Q

T/F Refrigeration and freezing are usually not for static, but sterlization

A

F, it’s usually used for static which means it slows metabolism but will grow when temps are raised

104
Q

What is pascalization?

A

High pressure used in food industry to kill microbes

105
Q

What is desiccation?

A

Drying or dehydration

106
Q

What method of sterilization is used for millennia to preserve foods like raisins, prunes, jerky, etc.

A

Desiccation

107
Q

What is it called when using freeze-drying; rapid freezing then placed under vacumn?

A

Lypophilization

108
Q

Salts or sugars in jams are helpful for desiccation sterilization because they lower _______?

A

Water activity of foods/materials without physical drying

109
Q

What is ionizing radiation?

A

Radiation that enters into the cells and disrupts molecular structures such as DNA

110
Q

T/F ionizing radiation can be used to sterilize non-autoclavable items

A

True

111
Q

What doesn’t penetrate through glass, plastics, etc. but can damage cells w/ direct exposure

A

Non-ionizing radiation

112
Q

What is UV irradiation?

A

Forms thymine dimers in DNA causing lethal mutations

113
Q

What are high frequency sound waves that disrupt cell structure and causes bubbles to form inside cells and induce lysis?

A

Sonication

114
Q

What is the use of barrier to physically separate microbes?

A

Filtration

115
Q

What does membrane filtration do?

A

Removes microbes from liquid samples

116
Q

How is air commonly filtered?

A

Through high-efficiency particulate air (HEPA) filters

117
Q

What is the correct order of the steps of biofilm formation?
1. Production of extracellular polymeric substance (EPS)
2. Attachment of planktonic cells to a substrate
3. Attachment becomes irreversible; cells become sessile
4. Growth and division on substrate
5. Attachment of secondary colonizers and dispersion of microbes to new locations

A

2, 3, 4, 1, 5

Microbiology for Nursing (16 decks)

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