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Microbiology > test two lec 9 part 2 > Flashcards

test two lec 9 part 2 Flashcards

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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
how can oxygen damage cells
damage RNA, DNA, proteins and lipids
26
what enzymes do aerobic organisms have that help fight reactive oxygen species
superoxide deaminase catalase peroxidase
27
what are strict aerobes
an organism that performs aerobic respiration and can only grown in the presence of oxygen oxygen is terminal electron acceptor
28
what are strict anaerobes
an organism that does not grow in the presence of oxygen | dies in response to oxygen due to ROS
29
strict anaerobes use what type of mechanism
fermentation | anaerobic respiration
30
what are facultative anaerobes
an organism that can grow in either the presence or absence of oxygen
31
what are aerotolerant anaerobes
an organism that does not use oxygen for metabolism but can grow in the presence of oxygen contain enzymes to protect from ROS
32
what are microaerophiles
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
33
microaerophiles are also what
capnophiles
34
what are capnophiles
bacteria that require increased concentrations of carbon dioxide and some are pathogenic
35
how do you culture anaerobes in lab
oxygen removing techniques
36
what is oxygen removing technique
degassing media and including special reducing agents or enzyme systems
37
what are some oxygen removing techniques
anaerobe jar: O2 removed by palladium plus H2 | anaerobe chamber with airlock system and glove ports: O2 removed replaced with N2
38
what are oligotrophs
organisms with a high rate of growth at low solute concentrations
39
what are oligotrophic conditions
low nutrient concentrations (1 to 5 mg C/L)
40
what do oligotrophs have on their membrane
prothecae
41
what are prothecae
thin extensions of membrane and cell well that expand the surface area of cell and increase nutrient transport capacity
42
what gene systems are affected when nutrients decline
growth rate slows, daughter cells become smaller
43
starvation elicits what response
starvation response
44
what happens during starvation response
enzymes are produced to increase efficiency of nutrient gathering and protect cell macromolecules from damage cells begin to make and store glycogen
45
what triggers the starvation response
accumulation of small signal molecules such as cAMP or guanosine tetraphosphate
46
during starvation response, when cells growing on nutrient deprived agar what happens
cells form colonies and intricate shapes that help population cope to food stress
47
what is eutrophication
the sudden infusion of large quantities of a formerly limiting nutrient
48
what is a downfall of eutrophication
unrestricted growth consumes other nutrients to a degree that threatens the existence of competing species
49
static does what to growth
inhibits
50
cidal does what to growth
kills cells
51
germicidal does what
kills pathogens but not spores
52
sterilization
process by which all living cells, spores and viruses are killed/destroyed
53
disinfection
killing or removal of disease producing organism from inanimate surfaces does not necessarily result in sterilization pathogens killed but not all microbes
54
antisepsis
killing or removal of pathogens from the surface of living tissues
55
sanitation
reducing the microbial population to safe levels and usually involves both cleaning and disinfecting an object
56
what factors influence the efficacy of given chemical agent
presence of organic matter kinds of organisms present corrosiveness stability, odor, and surface tension
57
how does presence of organic matter affect efficacy of chemical agent
chemical will bind, lowering agents effectivenes
58
how does corrosiveness affect efficacy of chemical agent
shouldnt damage surface or skin
59
what are some commercial disinfectant and antiseptics
ethanol iodine chlorine ethylene oxide
60
what are surfactants
detergents
61
how do surfactants work
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
how do low molecular weight aldehydes in disinfectants
formaldehyde | combine with and inactivate proteins and nucleic acids
63
what are antibiotics
chemical compounds synthesized by one microbe that kill or inhibit the growth of other microbial species
64
what does penicillin do
mimics part of bacterial cell wall and prevents bacterial cell wall formation bactericidal
65
what do antibiotics target
protein synthesis DNA replication cell membranes
66
bacteria can attack same species but wont attack itself bc
alters its own receptors
67
how can bacteria develop resistance to disinfectants and antibiotics
alter fatty acid synthesis protein produce membrane spanning multidrug efflux pumps biofilms
68
what are the five physical agents that kill microbes
``` high temp pasteurization cold filtration irradiation ```
69
how does high temp work with killing microbes
moist heat, water penetrates cells
70
how to kill spores
high pressure and temp such as a steam autoclave
71
what is pasteurization
the heating of food at a temp and time combination that will kill Coxiella burnetti
72
what does pasteurization not want to do
kill all microorganisms in food just reduce the viable pathogens
73
how is cold used in killing microbes
low temps slow down growth and preserve strains | helps with storage of cultures: glycerol
74
how does glycerol store strains
prevent production of ice crystals that can pierce cells
75
what is lyophilization
freeze drying | quick freezing at low temp to prevent formation of ice crystals, apply vacuum to remove water, cells store as powder
76
how does filtration work
micropore filters with pore size of .2 micrometers to remove microbial cells but not viruses can remove cells without heat
77
can air be sterilized by filtration
yes | laminar flow biological safety cabinet
78
how does irradiation work for killing microbes
UV light | gamma rays, electron beams, x-rays
79
when is UV light used
to sterilize surface | poor penetrating power
80
what has high penetrating power
gamma rays, electron beams, x-rays
81
what is used to irradiate foods and other heat sensitive items
gamma rays, electron beams and x-rays
82
what happens with microbes and radiation
water and other intracellular molecules absorb energy and form chemicals that damage DNA and scramble genetic info
83
what are some variables of microbes to radiation
size of DNA rate at which they can repair damaged DNA takes a higher dose for frozen food contaminated with microbes
84
what is the worlds toughest bacterium
Deinococcus rediodurans
85
what can deinococcus rediodurans survive
``` high amounts of uv radiation cold dehydration acidity vacuum conditions ```
86
what os s[ecial about deinococcus rediodurans
ability to repair damaged DNA in less than 24 hours | has been genetically engineered for use in bioremediation
87
what is biocontrol
the use of one microbe to control the growth of anothre
88
what are probiotics
contain certain microbes that, when ingested, aim to restore balance to intestinal flora
89
what is phage therapy
aims to treat infectious disease with virus targeted to the pathogen

Microbiology (16 decks)

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