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Microbiology > test two lec 9 part 1 > Flashcards

test two lec 9 part 1 Flashcards

(77 cards)

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1
Q

when bacteria is faced with environmental stress, what happens

A

endospores
heterocysts
fruiting bodies
aerial hyphae

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2
Q

what species can produce dormant spores

A

clostridium and bacillus species

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3
Q

what are dormant spores resistant to

A

heat and dessication

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4
Q

clostridium causes

A

tetanus, botulism and diarrhea

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5
Q

baillus causes

A

anthrax

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6
Q

when do spores grow and need nutrients

A

when they germinate

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7
Q

starvation initiates an elaborate genetic program that involves

A

asymmetrical cell division process that produces a forespore which ultimately becomes and endospore

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8
Q

sporulation can be divided into discrete stages based on

A

morphological appearance

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9
Q

how do endospores survive

A

dessication: have less water than in vegetative state

packed with small acid soluble proteins that bind to and protect DNA from UV light and various toxic chemicals

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10
Q

what is germination

A

wakes cell, dissolves spore coat, releases viable vegetative cell

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11
Q

what is an anabaena

A

autotrophic cyanobacterium

makes O2 via photosynthesis and can fix N2 to make ammonia

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12
Q

what cyanobacterium uses heterocysts

A

anabaena

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13
Q

how do heterocysts work

A

ever 10th photosynthetic cell converts to this
loses ability to fix CO2 and forms envelop to limit O2 access
allows to fix nitrogen anaerobically while other cells maintain oxygenic photosynthesis

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14
Q

what are fruiting bodies

A

reproductive structure

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15
Q

what bacteria uses gliding motility

A

myxococcus xanthus

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16
Q

what triggers fruiting bodies

A

starvation triggers aggregation of 100000 cells

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17
Q

fruiting bodies are similar to

A

biofilms

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18
Q

cells in the middle of fruiting bodies differentiate into

A

spores to help find nutrient sources

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19
Q

gliding motility uses what for movement

A

swarming

light moltilty

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20
Q

what is sacrophutic

A

process dead/ decaying matter

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21
Q

differences in growth rates of organisms is determined by

A

nutrition and niche-specific physical parameters like temp and pH

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22
Q

where do slow growing microbes live

A

in low energy environments

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23
Q

what are mesophiles

A

grow in normal conditions

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24
Q

mesophiles grow in what conditions

A

20 to 40 celsiuse
neutral pH
.9% salt
ample nutrients

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25
what are extremophiles
organisms inhabiting any ecological niche outside the normal window
26
what is the main criterion that a specie inhabits its environmental inhabitat
the tolerance of that organisms proteins other macromolecular structures to the physical conditions within that niche
27
can multiple extremes be met in one environment
yes yellowstone hot spring high acid/high alkalinity and high temp
28
does a bacteria cell's temp match its immediate environment
yes
29
changes in temp of bacterias environment affects
``` molecular motion and impacts microbial physiology membrane fluidity nutrient transport DNA/RNA stability enzyme structure and function ```
30
what do each organism has that defines its growth limits
optimum temp | plus min and max temp
31
when does fastest growth rate occur regarding to temp
occurs at temps where all of the cells proteins work most efficiently as a group to produce energy and synthesize cell components
32
when does growth stop according to temp
when rising temp cause critical enzymes/ cell structures to fail
33
what happens to cell growth at cold temps
growth ceases bc processes slow down and the cell membrane is less fluid
34
why is the cell membrane when it is in a fluid state so important
for cell expansion and insertion of membrane transport proteins
35
if a microbe can grow at higher temp what does that mean for their rate of growth
they achieve higher rates of growth
36
temp for psychrophiles
0-25 celsius
37
temp for mesophiles
15 to 45 celsius
38
temp for thermophiles
45 to 80 celsius
39
temp for hyperthermophiles/ extreme thermophiles
80 to 121 celsius
40
how we know about pathoges, DNA/RNA, proteins, and membran came from the study of
mesophiles
41
what temp is human bacterial pathogens of mesophiles
37 celsius
42
what makes mesophiles good lab rats
don't need high temp or high or low pressure
43
what type of environments do psychrophiles live in
arctic/antarctic | deep sea
44
what are the proteins like in psychrophiles
more flexible and require less energy (heat) to function | but they denature at lower temp than mesophiles
45
what are the membranes like of psychrophiles
more fluid | higher proportion of unsaturated fatty acids, kinks lipids dont pack as tightly
46
in psychrophiles what helps lower the freezing point
antifreeze proteins and cryoprotectants
47
what is so great about psychrophiles enzymes
used for commercial interest
48
hyperthermophiles was the first source of hight temp...
DNA polymerase
49
what hyperthermophile was isolated from hot spring at yellowstone national park
thermus aquaticus
50
what do thermophiles have that help them adapt
chaperone proteins DNA binding proteins and enzymes to tightly coil DNA membranes packed tightly
51
what are chaperone proteins
help refold other proteins as they undergo thermal denaturation
52
what kind of membranes do thermophiles have
more saturated linear lipids | packed more tightly
53
what are the enzymes like in thermophiles
dont unfold as easily hold shape better at higher temp low amts of glycine, enzymes less flexible amino termini are tied down by H bonding to other parts of protein makes protein harder to denature
54
what is heat shock response
rapid temp changes experienced during growth activates batches of stress response genes
55
what protein products are associated with heat shock response
chaperones and enzymes
56
heat shock response occurs in all
domains
57
bacteria and archea not so good in what temp
below 0 celsius and above 100 celsius
58
what is eukaryotes temp limits
10 to 65 celsius
59
what are protists upper temp limit
50 celsius
60
what are fungi upper temp lmit
60 celsius
61
mesophiles want to live at what pressure
sea level
62
barophiles and piezophiles live in what pressure
high pressure | 1000 atm
63
barotolerant organisms grow well over the range of
1 to 50 MPa | but growth rate falls off after that
64
what are the adaptations that barophiles have to survive high pressure
higher levels of polyunsaturated fatty acids to increase membrane fluidity unique ribosome structures to tolerate high pressure
65
microbes can only use what kind of water
water not bound to ions or other solute solution
66
what is water activity
a measure of how much water is available for use
67
how is osmolarity related to water activity
inversly
68
the more particles in solution the greater the
osmolarity and lower the water activity
69
what are aquaporins
membrane channel protein that allow water to traverse the membrane much faster than by diffusion
70
are aquaporins active transport
no but is passive
71
when are aquaporins used
during osmotic stress when cell needs water
72
what are the two ways microbes can minimize osmotic stress
import solutes or leak solutes
73
in a hypertonic media, bacteria protect their internal water by synthesizing or importing
compatible solutes that increase intracellular osmolarity
74
in hypotonic media, pressure sensitive or mechanosensitive channels can be used
to leak solutes out of cell | keep water from rushing in
75
most bacteria require salt concentrations of
0.1 to 1 M
76
halophiles require
high salt concentrations | 2 to 4 M
77
halophiles use what to excrete Na+ and replace it with cations
special ion pumps

Microbiology (16 decks)

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