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Microbiology > test two lec 9 part 1 > Flashcards

test two lec 9 part 1 Flashcards

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Biology 101 flashcards
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
Q

what are extremophiles

A

organisms inhabiting any ecological niche outside the normal window

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26
Q

what is the main criterion that a specie inhabits its environmental inhabitat

A

the tolerance of that organisms proteins other macromolecular structures to the physical conditions within that niche

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27
Q

can multiple extremes be met in one environment

A

yes
yellowstone hot spring
high acid/high alkalinity and high temp

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28
Q

does a bacteria cell’s temp match its immediate environment

A

yes

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29
Q

changes in temp of bacterias environment affects

A 
molecular motion and impacts microbial physiology
membrane fluidity
nutrient transport
DNA/RNA stability 
enzyme structure and function
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30
Q

what do each organism has that defines its growth limits

A

optimum temp

plus min and max temp

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31
Q

when does fastest growth rate occur regarding to temp

A

occurs at temps where all of the cells proteins work most efficiently as a group to produce energy and synthesize cell components

32
Q

when does growth stop according to temp

A

when rising temp cause critical enzymes/ cell structures to fail

33
Q

what happens to cell growth at cold temps

A

growth ceases bc processes slow down and the cell membrane is less fluid

34
Q

why is the cell membrane when it is in a fluid state so important

A

for cell expansion and insertion of membrane transport proteins

35
Q

if a microbe can grow at higher temp what does that mean for their rate of growth

A

they achieve higher rates of growth

36
Q

temp for psychrophiles

A

0-25 celsius

37
Q

temp for mesophiles

A

15 to 45 celsius

38
Q

temp for thermophiles

A

45 to 80 celsius

39
Q

temp for hyperthermophiles/ extreme thermophiles

A

80 to 121 celsius

40
Q

how we know about pathoges, DNA/RNA, proteins, and membran came from the study of

A

mesophiles

41
Q

what temp is human bacterial pathogens of mesophiles

A

37 celsius

42
Q

what makes mesophiles good lab rats

A

don’t need high temp or high or low pressure

43
Q

what type of environments do psychrophiles live in

A

arctic/antarctic

deep sea

44
Q

what are the proteins like in psychrophiles

A

more flexible and require less energy (heat) to function

but they denature at lower temp than mesophiles

45
Q

what are the membranes like of psychrophiles

A

more fluid

higher proportion of unsaturated fatty acids, kinks lipids dont pack as tightly

46
Q

in psychrophiles what helps lower the freezing point

A

antifreeze proteins and cryoprotectants

47
Q

what is so great about psychrophiles enzymes

A

used for commercial interest

48
Q

hyperthermophiles was the first source of hight temp…

A

DNA polymerase

49
Q

what hyperthermophile was isolated from hot spring at yellowstone national park

A

thermus aquaticus

50
Q

what do thermophiles have that help them adapt

A

chaperone proteins
DNA binding proteins and enzymes to tightly coil DNA
membranes packed tightly

51
Q

what are chaperone proteins

A

help refold other proteins as they undergo thermal denaturation

52
Q

what kind of membranes do thermophiles have

A

more saturated linear lipids

packed more tightly

53
Q

what are the enzymes like in thermophiles

A

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
Q

what is heat shock response

A

rapid temp changes experienced during growth activates batches of stress response genes

55
Q

what protein products are associated with heat shock response

A

chaperones and enzymes

56
Q

heat shock response occurs in all

A

domains

57
Q

bacteria and archea not so good in what temp

A

below 0 celsius and above 100 celsius

58
Q

what is eukaryotes temp limits

A

10 to 65 celsius

59
Q

what are protists upper temp limit

A

50 celsius

60
Q

what are fungi upper temp lmit

A

60 celsius

61
Q

mesophiles want to live at what pressure

A

sea level

62
Q

barophiles and piezophiles live in what pressure

A

high pressure

1000 atm

63
Q

barotolerant organisms grow well over the range of

A

1 to 50 MPa

but growth rate falls off after that

64
Q

what are the adaptations that barophiles have to survive high pressure

A

higher levels of polyunsaturated fatty acids to increase membrane fluidity
unique ribosome structures to tolerate high pressure

65
Q

microbes can only use what kind of water

A

water not bound to ions or other solute solution

66
Q

what is water activity

A

a measure of how much water is available for use

67
Q

how is osmolarity related to water activity

A

inversly

68
Q

the more particles in solution the greater the

A

osmolarity and lower the water activity

69
Q

what are aquaporins

A

membrane channel protein that allow water to traverse the membrane much faster than by diffusion

70
Q

are aquaporins active transport

A

no but is passive

71
Q

when are aquaporins used

A

during osmotic stress when cell needs water

72
Q

what are the two ways microbes can minimize osmotic stress

A

import solutes or leak solutes

73
Q

in a hypertonic media, bacteria protect their internal water by synthesizing or importing

A

compatible solutes that increase intracellular osmolarity

74
Q

in hypotonic media, pressure sensitive or mechanosensitive channels can be used

A

to leak solutes out of cell

keep water from rushing in

75
Q

most bacteria require salt concentrations of

A

0.1 to 1 M

76
Q

halophiles require

A

high salt concentrations

2 to 4 M

77
Q

halophiles use what to excrete Na+ and replace it with cations

A

special ion pumps

Microbiology (16 decks)

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