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Slide deck 4 Flashcards

1
Q

what must an agar plat contain?

A

all nutrients required for growth

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2
Q

what is a colony forming unit (CFU)?

A

one microbe

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3
Q

Are cells always either alive or dead?

A

no, they can exist in a variety of states between fully viable and actually dead

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4
Q

what is the membrane filter method used for?

A

this allows for determination of colony numbers of bacteria in a sample

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5
Q

T/F: bacteria grows on the membrane during the membrane filter method

A

true

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6
Q

what is a counting chamber?

A

this is a slide with depressed areas where the bacteria will sit in under a cover glass

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7
Q

T/F: counting chambers are only used for counting bacteria

A

false, works for both prokaryotes and eukaryotes

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8
Q

what do counting chambers tell the observers

A

size and morphology of the microorganisms

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9
Q

what is flow cytometry?

A

microbial suspension forced through a small orifice with a laser light beam and the microbes scatter the light

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10
Q

how are the microbes quantified in flow cytometry?

A

each light scattering event is detected independently and the number of events represents the number of cells

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11
Q

what are electrical microbe counters?

A

microbial cell passes through a hole, electrical resistance increases, the cell is counted

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12
Q

T/F: cell concentration only counts viable cells.

A

false it also includes dead cells

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13
Q

What is a batch culture?

A

you start with a set group letting them incubate for X days and then later get products

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14
Q

what is a continuous culture?

A

this is an infinitly run culture continually adding new nutrients and siphoning off at the same rate removing fluids and some bacteria

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15
Q

what does continuous cultures maintain cells at?

A

the log phase at constant biomass concentration

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16
Q

how are most penicillins made?

A

through continuous culturing

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17
Q

why do we use continuous culturing?

A

because this is the closest we can get to bacteria present in natural environments

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18
Q

what industries use continuous culturing?

A

food and industrial microbiology

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19
Q

what is a chemostat?

A

device used to continuously cultivate microorganisms in a controlled environment where fresh medium is constantly added while an equal volume of the culture is removed

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20
Q

How are chemostats made?

A

having the rate of incoming medium = the rate of removal of medium from vessel

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21
Q

What type of device is most stable in lower dilutions

A

chemostat

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22
Q

What is a turbidostat?

A

device where the growth rate of a microbial population is controlled by automatically adjusting the dilution rate based on the turbidity of the culture

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23
Q

how does a turbidostat operate best?

A

at high dilution rates

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24
Q

The ____ device contains all nutrients in excess.

A

turbidostat

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25
The ____ device contains all nutrients in excess.
chemostat
26
T/F: in chemostats and turbidostats there is always an air supply.
false, this depends on aerobic and anaerobicness of the bacteria
27
what does doubling time mean?
generation time (time required for the population to double in size)
28
as ____ increases there is more nutrients to increase.
dilution rate
29
what is the dilution rate?
rate at which the medium flows through vessels
30
what is the biggest difference of lab conditions to normal conditions?
pure cultures do not exist in nature, they compete not only for nutrients but space
31
most microbes live in a ____ state. What does that imply?
growth-arrested; microbes are effectively metabolically inactive for days because of the environment they are living in.
32
what kind of environment do microbes typically live?
dynamic oligotrophic environments
33
how did microbes evolve in response to starvation and environmental stress?
- morphological changes (endospores, flagella) - can use cellular components as nutrient storage - viable but not culturable state - biofilm formation increasing probablity of survival
34
T/F: biofilms are the default for bacteria.
true
35
what are biofilms
flagellated bacteria loose their flagella and secrete molecular glue and stick together
36
T/F: bacteria species work together and create a biofilm.
true, composed of all different species most of the time
37
what are biofilms typically made of?
polysaccharides
38
on plants where is a very important biofilm located?
on the root nodules
39
how do bacteria form the biofilms?
they reversibly attach to conditioned surfaces and release polysaccharides, proteins, and DNA to form EPS - after, additional polymers are produced as microbes reproduce and biofilm matures
40
If the environment changes (for the worse) what occurs to the biofilm?
the bacteria will detect the change and shift genetic programming to stop the EPS secretion and start secreting stuff to remove the biofilm
41
In biofilms there is a ____ transfer of DNA causing ____ changes in the cells.
horizontal; phenotypic
42
what does heterogeneity mean in biofilms?
differences in metabolic activity and locations of microbes
43
How do biofilms remove toxins and counteract bacterial gradient issues?
they have channels and pores that will flow out all the not needed stuff in the biofilm
44
What does the EPS do for the protection of microbes?
it can change the attached organisms physiology in many ways
45
what happens when biofilms form on medical implants?
illness and infections
46
T/F: the presence of bacterial biofilms influence the antibiotic protection.
true
47
why are biofilms the default?
it gives bacteria the security and protection that bacteria need.
48
What is quorum sensing?
chemical communication between bacteria
48
why do bacteria use quorum sensing?
biofilm is more successful
48
what is N-acylhomoserine lactone (AHL) and what kind of bacteria produces it?
it is an autoinducer produced by gram-negative organisms
49
what does AHL do?
diffuses across plasma membrane and induces expression of target genes regulating a variety of functions
50
T/F: quorums are very general and can be used for every species communication.
false, some are species specific
51
how is quorum's used when not in a biofilm?
basically a small chemical sensor of knowing which bacteria are in the area not only of the same species.
52
What do AHL do for quorum sensing?
this can count bacteria like a proxy-esitmate finding out how many bacteria are in the environment.
53
what do processes regulated by quorum sensing involve?
host-microbe interactions
54
what is increased in quorum sensing systems?
pathogenicity and virulence factor production; antibiotic resistance from DNA uptake
55
what is a symbiosis example of biofilm bacteria-host interactions?
bobtail squids which eats certain types of bacteria causing them to bioluminesce to attract prey
56
what is an interdomain communication example of biofilm?
bacteria (rhizobium) interacts with leguminous plants for nitrogen fixation
57
what do most extremeophiles have?
very good DNA repair systems
58
what is the name of cold-loving bacteria?
psychrophiles, and psychrotrophs
59
what is the name of temperate loving bacteria?
mesophiles
60
what is the name of hot loving bacteria?
thermophiles and hyperthermophiles
61
what would the outcome of taking a hyperthermophile and placing them in a 20ºC environment? why?
it would die, their adaptations are so niche and unique for their specific temperatures
62
how are protein structures stabilized in thermophiles?
more H bonds and disulphide bonds, more proline, and more chaperones
63
how do chaperones/chaperonins help thermophiles?
they take in polypeptides and spit out the correctly folded proteins
64
how are membranes stabilized in thermophiles?
more saturated, branched and higher molecular weight lipids, and ether linkages (in archaeal membranes)
65
What are halophiles?
love salt
66
how do you distinguish extreme halophiles?
they will have a square crystalline shape
67
what do extreme halophiles require?
salt conc. between 3M and 6.2M, in addition to extremely high conc. of potassium
68
how do neutrophiles respond to external pH changes?
exchange potassiums for protons
69
T/F: halophiles require an inner pH to be very high to survive.
false no bacteria can have a high pH they counteract it in some way
70
What is the acidic tolerance response?
- pump protons out of the cell - some synthesize acid and heat shock proteins that will protect other proteins
71
how do many microorganisms change their pH of their habitats?
they produce acidic or basic waste products creating a "bubble of neutrality"
72
what does the growth in the presence of different oxygen concentration depend on?
metabolic processes, electron transport chains (ETC), reactive oxygen species tolerance
73
in an obligate aerobe what enzymes are present or not present?
SOD and Catalase are present
74
in a strict anaerobe what enzymes are present or not present?
neither SOD or Catalase
75
if a bacteria has SOD but not catalase what kind of bacteria is it?
aerotolerant anaerobe
76
what bacteria(s) have both SOD and Catalase?
faculatative anaerobe, obligate aerobes, and microaerophiles (but these usually have little to no catalase)
77
all bacteria that can deal with oxygen have what kind of enzymes?
anti-oxygen enzymes
78
What are the anti-oxygen enzymes?
superoxide dismutase (SOD), catalase, and peroxidase
79
what are barophilic microbes?
high pressure lovers
80
T/F: barophilic bacteria are strictly barophilic
false, these will have a combinations of other extreme environments
81
what does ionizing radiation do?
fundamentally damages DNA breaking causing mutations and can cause cancer or death immediately
82
what is extremely resistant to radiation?
endospores and D. radiodurans
83
how do radiodurans exist? why?
in tetrads always, this makes less of a chance of something happening to all cells
84
what are radiodurans extremely rich in?
Mn
85
T/F: radiodurans are extremely different to other bacteria which is why they are so resistant.
false they have small changes making them have a large adaptation.
86
what structure do radiodurans have a lot of? what is in them? Why?
lots of storage granules of carbohydrates and phosphates for building blocks of DNA/RNA
87
radiodurans have a lot of enzymes to do what? why?
lots of enzymes for the conversion of glucose to ribose and deoxyribose providing the building blocks for genetic repair
88
when radiodurans are under attack what do they do?
secrete proteases to break up amino acids in the environment
89
T/F: all the adaptations of radiodurans are unique.
false, they are all common amongst bacteria but they exist in much higher amounts
90
since dealing with rogue amino acids is extremely metabolically exhausting why does it happen?
it protects them and they can use the now free floating proteins to get more amino acids to build more stuff.
91

Microbiology (7 decks)

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