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Microbiology > test two lec 9 part 2 > Flashcards

test two lec 9 part 2 Flashcards

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Biology 101 flashcards
1
Q

what has a direct effect on cells macromolecular structures

A

concentration of H+ or hydronium ions

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2
Q

extreme concentrations of hydronium or hydroxide ions in a solution will limit growth of what type of phile

A

mesophile

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3
Q

living cells tolerate a grater range in environmental concentration of what than of virtually any other chemical substance

A

hydrogen ions

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4
Q

the charges on amino and carboxyl groups within a protein contribute to what

A

the intramolecular bonds that govern protein shape and protein activity

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5
Q

what optimal pH

A

5 to 8.5

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6
Q

can the intracellular pH of microbe be different than environment

A

yes

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7
Q

what about the membrane that allows bacteria to regulate internal pH

A

membrane is impermeable to protons

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8
Q

if there are large differences between intra and extracellular pH, this could lead to what on microbes

A

leakage of protons either directly or via proteins

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9
Q

what can accelerate leakage of hydrogen ions in membrane

A

weak acids

this causes the internal pH to acidify

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10
Q

what are the three classes of organisms that are differentiated by pH

A

neutralophiles
acidophiles
alkaliphiles

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11
Q

what is the pH for neutralophiles

A

5 to 8

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12
Q

where do you find neutralophiles

A

human pathogens

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13
Q

can the neutralophiles fluctuate their pH

A

yes
they do this to maintain their metabolism
stay within .5 of external pH

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14
Q

what is the pH for acidophiles

A

0 to 5

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15
Q

acidophiles are mostly

A

chemoautotrophs bc they oxidize reduced metals and generate strong acids

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16
Q

acidophiles have what kind of membrane

A

tetrether lipids which decrease proton permeability, allow for growth

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17
Q

what is the pH for alkaliphiles

A

9 to 11

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18
Q

where are alkaliphiles found

A

soda lakes

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19
Q

what makes alkaliphiles special

A

contain cytoplasmic enzymes that have ordinary optima pH so cells have surface barriers that sequester cytoplasmic enzymes from high extracellular pH

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20
Q

what is in an alkaliphile membrane that helps with pH

A

hexosamines in peptidoglycan
high level of diether lipids that help from proton leakage
Na+/H+ antiporters: bring in protons and Na+ released

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21
Q

what can microbes do if placed in conditions below optimum

A

exchange extracellular K+ for intracellular H+ when internal pH becomes too low

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22
Q

what molecules can microbes use to change pH

A

amino acid decarboxylases and deaminases

drain protons from cell

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23
Q

microbes also possess an emergency global response system which does what

A

acid tolerance or acid resistance by protein levels increasing when others decrease

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24
Q

when is oxygen toxic to cells

A

cells that do not have enzymes capable of efficiently destroying the reactive oxygen species
anaerobes

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25
Q

how can oxygen damage cells

A

damage RNA, DNA, proteins and lipids

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26
Q

what enzymes do aerobic organisms have that help fight reactive oxygen species

A

superoxide deaminase
catalase
peroxidase

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27
Q

what are strict aerobes

A

an organism that performs aerobic respiration and can only grown in the presence of oxygen
oxygen is terminal electron acceptor

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28
Q

what are strict anaerobes

A

an organism that does not grow in the presence of oxygen

dies in response to oxygen due to ROS

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29
Q

strict anaerobes use what type of mechanism

A

fermentation

anaerobic respiration

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30
Q

what are facultative anaerobes

A

an organism that can grow in either the presence or absence of oxygen

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31
Q

what are aerotolerant anaerobes

A

an organism that does not use oxygen for metabolism but can grow in the presence of oxygen
contain enzymes to protect from ROS

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32
Q

what are microaerophiles

A

organisms that require oxygen at a concentration lower that that of the atmosphere, but unable to grow in high oxygen environments
decreased levels of enzymes

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33
Q

microaerophiles are also what

A

capnophiles

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34
Q

what are capnophiles

A

bacteria that require increased concentrations of carbon dioxide and some are pathogenic

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35
Q

how do you culture anaerobes in lab

A

oxygen removing techniques

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36
Q

what is oxygen removing technique

A

degassing media and including special reducing agents or enzyme systems

37
Q

what are some oxygen removing techniques

A

anaerobe jar: O2 removed by palladium plus H2

anaerobe chamber with airlock system and glove ports: O2 removed replaced with N2

38
Q

what are oligotrophs

A

organisms with a high rate of growth at low solute concentrations

39
Q

what are oligotrophic conditions

A

low nutrient concentrations (1 to 5 mg C/L)

40
Q

what do oligotrophs have on their membrane

A

prothecae

41
Q

what are prothecae

A

thin extensions of membrane and cell well that expand the surface area of cell and increase nutrient transport capacity

42
Q

what gene systems are affected when nutrients decline

A

growth rate slows, daughter cells become smaller

43
Q

starvation elicits what response

A

starvation response

44
Q

what happens during starvation response

A

enzymes are produced to increase efficiency of nutrient gathering and protect cell macromolecules from damage
cells begin to make and store glycogen

45
Q

what triggers the starvation response

A

accumulation of small signal molecules such as cAMP or guanosine tetraphosphate

46
Q

during starvation response, when cells growing on nutrient deprived agar what happens

A

cells form colonies and intricate shapes that help population cope to food stress

47
Q

what is eutrophication

A

the sudden infusion of large quantities of a formerly limiting nutrient

48
Q

what is a downfall of eutrophication

A

unrestricted growth consumes other nutrients to a degree that threatens the existence of competing species

49
Q

static does what to growth

A

inhibits

50
Q

cidal does what to growth

A

kills cells

51
Q

germicidal does what

A

kills pathogens but not spores

52
Q

sterilization

A

process by which all living cells, spores and viruses are killed/destroyed

53
Q

disinfection

A

killing or removal of disease producing organism from inanimate surfaces
does not necessarily result in sterilization
pathogens killed but not all microbes

54
Q

antisepsis

A

killing or removal of pathogens from the surface of living tissues

55
Q

sanitation

A

reducing the microbial population to safe levels and usually involves both cleaning and disinfecting an object

56
Q

what factors influence the efficacy of given chemical agent

A

presence of organic matter
kinds of organisms present
corrosiveness
stability, odor, and surface tension

57
Q

how does presence of organic matter affect efficacy of chemical agent

A

chemical will bind, lowering agents effectivenes

58
Q

how does corrosiveness affect efficacy of chemical agent

A

shouldnt damage surface or skin

59
Q

what are some commercial disinfectant and antiseptics

A

ethanol
iodine
chlorine
ethylene oxide

60
Q

what are surfactants

A

detergents

61
Q

how do surfactants work

A

hyrdophobic and hydrophilic ends will emulsify fat into water

cationic: gain access to neg charge bacterial cell and disrupt membranes
anionic: not anitmicrobial but help with mechanical removal

62
Q

how do low molecular weight aldehydes in disinfectants

A

formaldehyde

combine with and inactivate proteins and nucleic acids

63
Q

what are antibiotics

A

chemical compounds synthesized by one microbe that kill or inhibit the growth of other microbial species

64
Q

what does penicillin do

A

mimics part of bacterial cell wall and prevents bacterial cell wall formation
bactericidal

65
Q

what do antibiotics target

A

protein synthesis
DNA replication
cell membranes

66
Q

bacteria can attack same species but wont attack itself bc

A

alters its own receptors

67
Q

how can bacteria develop resistance to disinfectants and antibiotics

A

alter fatty acid synthesis protein
produce membrane spanning multidrug efflux pumps
biofilms

68
Q

what are the five physical agents that kill microbes

A 
high temp
pasteurization
cold
filtration
irradiation
69
Q

how does high temp work with killing microbes

A

moist heat, water penetrates cells

70
Q

how to kill spores

A

high pressure and temp such as a steam autoclave

71
Q

what is pasteurization

A

the heating of food at a temp and time combination that will kill Coxiella burnetti

72
Q

what does pasteurization not want to do

A

kill all microorganisms in food just reduce the viable pathogens

73
Q

how is cold used in killing microbes

A

low temps slow down growth and preserve strains

helps with storage of cultures: glycerol

74
Q

how does glycerol store strains

A

prevent production of ice crystals that can pierce cells

75
Q

what is lyophilization

A

freeze drying

quick freezing at low temp to prevent formation of ice crystals, apply vacuum to remove water, cells store as powder

76
Q

how does filtration work

A

micropore filters with pore size of .2 micrometers to remove microbial cells but not viruses
can remove cells without heat

77
Q

can air be sterilized by filtration

A

yes

laminar flow biological safety cabinet

78
Q

how does irradiation work for killing microbes

A

UV light

gamma rays, electron beams, x-rays

79
Q

when is UV light used

A

to sterilize surface

poor penetrating power

80
Q

what has high penetrating power

A

gamma rays, electron beams, x-rays

81
Q

what is used to irradiate foods and other heat sensitive items

A

gamma rays, electron beams and x-rays

82
Q

what happens with microbes and radiation

A

water and other intracellular molecules absorb energy and form chemicals that damage DNA and scramble genetic info

83
Q

what are some variables of microbes to radiation

A

size of DNA
rate at which they can repair damaged DNA
takes a higher dose for frozen food contaminated with microbes

84
Q

what is the worlds toughest bacterium

A

Deinococcus rediodurans

85
Q

what can deinococcus rediodurans survive

A 
high amounts of uv radiation
cold 
dehydration
acidity
vacuum conditions
86
Q

what os s[ecial about deinococcus rediodurans

A

ability to repair damaged DNA in less than 24 hours

has been genetically engineered for use in bioremediation

87
Q

what is biocontrol

A

the use of one microbe to control the growth of anothre

88
Q

what are probiotics

A

contain certain microbes that, when ingested, aim to restore balance to intestinal flora

89
Q

what is phage therapy

A

aims to treat infectious disease with virus targeted to the pathogen

Microbiology (16 decks)

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