Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

microbiology exam 2 > chapter 9 > Flashcards

chapter 9 Flashcards

(97 cards)

Start Studying
0
Q

how can you control growth microorganisms ?

A
  1. killing microoirganisms
  2. inhibiting growth of microorganisms
  3. removing them
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
1
Q

what is meant by microbial control?

A

reduction in number and activity.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

cidal agents=

A

kill

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

static agents=

A

inhibit

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

sterilization?

A

kills or removes all living microbes.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

disinpection?

A

use of physical/chemical agents(disinfectants) to kill or destroy microbes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

antispsis?

A

the process

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

antiseptic?

A

chemical agents to kill/destroy microbes in animate(living) objects

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

degerming?

A

removal of microbes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

sanitation?

A

disinfecting plates, utensils, and others used by the public

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

pasteurization ??

A

heating to a certain temp. to kill the most resistant bacteria.
ex: mycrobial tuberculosis (milk)
CANNOT KILL ENDOSPORES

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

what is microbial death?

A
  • permanent loss of reproductive ability

- exponential (die gradually)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

what are the mode of actions of antimicrobial agents?

A
  • alteration of cell walls and membranes

- damage of proteins and nucleic acids

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

what are the characteristics of an ideal antimicrobial method-

A
  • inexpensive *can be cheap but harmful.
  • fast acting
  • stable -harmless
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

what are the factors that affect the efficacy of antimicrobial agents?

A

-site to be treated(hospital or home)
-relative susceptibility of organisms(vegetative cells vs. endospores)
-enviromental
temp, pH, presence of organic matter

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

compare susceptibility of vegetative cells with endospores to antimicrobial agents.

A 
vegetative= active 
endospores= inactive= very resistant
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

what is the effect of temp on the action of antimicrobial agents?

A

increase temp- hasten effect of microbial agent

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

what is the effect of pH on the action of antimicrobial agents?

A

heat is effective in acid than in alkali

increase temp = decreased pH

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

what are examples of organic matter that may affect the action of antimicrobial agent?

A

sputum, blood feces, urine

organic matter presence may lower the efficiency of antimicrobial agents

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

what is the effect of the presence of organic matter on the action of antimicrobial agents?

A
  • inactivates the agent
  • protects the microbes
  • intervenes with the penetration of the agent
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

two methods of microbial control?

A

physical

chemical

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

what is the mode of action of moist heat?

A

-denatures proteins and destroys cell membrane and cell wall

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

what are examples of methods to control microorganisms using moist heat?

A
  • boiling=100 degrees C
  • autoclaving
  • pasteurization
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

what is an autoclave?

A

pressure arises, temp rises to kill moist resistant microbes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
what happens to temp when pressure increases?
temp increase
25
which kill the microorganisms, the high temp or the press?
the temp
26
what is the time-temp requirements of sterilization using autoclave?
121 degrees C 15-20 mins 15 psi(pressure)
27
what is pasteurization?
- traditional method - cannot kill endospores process: historical pasteurization treatment: 63 degrees C for 30min process: flash treatment: 72 degrees C 15 seconds process: ultra-high temp treatment: 134 degrees C for 1 sec
28
antimicrobial agents that would damage the cell wall of bacteria will kill the bacterial because bacteria will....
be susceptible to lysis.
29
is moist head cidal or static method?
a-cidal.... = kills bacteria
30
what is the mode of action of dry heat?
oxidation, reduced into ashes
31
what are examples of method to control microorganisms using dry heat?
- complete incineration 1500 degrees C | - oven sterilization 1-2 hours at 160-170 degrees C
32
compare time and temp requirements of moist heat sterilization with dry heat sterilization.
* *transfer of heat is faster in moist heat. | - temps are higher in dry heat but the process is slower.
33
explain why the temp is lower and time is shorter in moist heat than in dry heat sterilization ..?
bc the water helps to denature microbes faster... water heats up faster.
34
what is the mode of action of low temp to microbial growth?
stops & slows growth & decreases metabolism
35
what are examples of methods to control microorganisms using low temp?
-regrigerator: around 4 degrees C -Freezer: ordinary freezer around -10 to -20 degrees C ultracold lab freezer typically -80 degrees C
36
refrigeration and freezing is what type of method? static or cidal? why?
static, bc it only inhibits the growth of microbes
37
temps are important for food safety, what is meant by danger zone?
the zone of fastest growth.
38
what is the temp range in the danger zone?
60 - 4 degrees C
39
phycrophils can spoil food in the _____________, and mesophiles grow faster in ___________ _________.
- frige | - danger zone
40
what is dessication?
removal of water
41
how does desiccation control microorganisms?
action: inhibits the growth and disrupts metabolism
42
what are examples of dessication methods?
- drying - add salt - add sugar
43
review hypertonic solutions.
...
44
what is water activity?
describes amount of water available for microbial growth.
45
differentiate water activity of food from moisture content of food...
water activity= free water; moisture content= free water& water bonded to other things.
46
water activity is expressed as ___________________________
aw or % equilibrium relative humidity(%ERH)
47
if the water activity of a certain food product is 0.4 what is the ERH?
4%
48
what is the min. aw of the following microorganisms? 1. normal bac 5. xerophilic molds 2. normal yeast 3. normal molds 6. osmpohilic yeast 4. halophilic bac
1. 0.91 (fresh meats, milk) 2. 0.88 (dry cheese, sponge cake) 3. 0.80 (condensed milk, flour0 4. 0.75 (jam, marshmellows) 5. 0.65 (rolled oats) 6. 0.60 (dried fruits)
49
what is membrane filtration? used for?
physically removes (degerming) microbes-- used for liquid materials that can't be sterilized.
50
what are examples of equipment that use membrane filtration?
- membrane filter - vacuum pump - ** microbes will be retained in the filter paper
51
describe how a laminar flow biological safety cabinet works to control microorganisms...?
air moves away from the person, up & thru a filter & then back out.
52
what are the 4 levels of safety in labs dealing with pathogens?
1. bio safety level 1 = handling pathogens that don't cause disease in healthy humans. 2. bio safety level 2 = handling moderately hazardous agents 3. bio safety level 3- handling microbes in safety cabinets 4. bio safety level 4 = handling of microbes that cause severe or fatal disease.
53
what are examples of ionizing radiations? what are their modes of action?
- gamma rays - x-rays * both cause damage to DNA and inhibits proteins
54
what is an example of non-ionizing radiations? what is its mode of action?
- ultraviolet rays | * cause damage to DNA and inhibits proteins
55
UV rays are __________ wave length, and ____________ energy.
longer, lower
56
what is the mode of action in microwave cooking?
- kills microbes **CIDAL | - denaturation of proteins due to heat generated
57
high level disinfectants/ and antiseptics kill _______________ intermediate level disinfectants/ and antiseptics kill ______________ low level disinfectants/ and antiseptics kill ________________
1. endospores and below 2. mycobacteria and below 3. trophozoites and below
58
what are the uses of phenol and phenolics?
intermediate- to low level disinfectants
59
what are examples of phenols and phenolics ??
lysol, triclosan, cresols
60
how do phenols and phenolics control microorganisms?
denatures proteins and disrupts cell membrane | *remain effective in organic contaminants
61
what are uses of alcohol?
intermediate-level disinfectants
62
what are examples of alcohol?
isopropyl alcohol (70%-90%) tinctures
63
how do alcohols control microorganisms?
denature proteins and disrupt cytoplasmic membrane.
64
alcohols are effective against what microbes? can alcohol kill endospores?
bacterialcidal, fungicidal, virocidal, & cannot kill endospores.
65
what is more effective in killing microorganisms? alcohol diluted with water or undiluted alcohol? explain.
70% is more effective bc water denatures proteins(or helps)
66
what are examples of halogens?
iodine, chorine, bromine, fluorine
67
what are the uses of halogens?
intermediate-level disinfectants and antiseptic chemicals.
68
how to halogens kill microorganisms?
damage enzymes by oxidation or denaturation
69
what is tincture?
mixture of water and alcohol
70
what is an iodophor?
iodine-containing organic cpd | ex: betadine= used for surgery and injection
71
what forms of chlorine are used to control microorganisms?
- cl2(disinfect water) - Na/Ca hypochlorite (house bleach) - ClO2 (disinfect building, ex: 9/11) - Chloramine (disinfect water)
72
why is bromine usually used in hot tubs?
bc bromine evaporates more slowly in higher temps, and last longer
73
what are examples of oxidizing agents?
peroxides, ozone, and per-acetic acid (sterilant)=sterilizes food utensils.
74
what are the uses for oxidizing agents?
high-level disinfectant
75
how do oxidizing agents kill microorganisms?
oxidation of cell structures and enzymes
76
what oxidizing agent is used to clean deep wounds ?
hydrogen peroxide.
77
what oxidizing agent is used to disinfect water?
ozone (O3) - not antiseptic
78
what oxidizing agent is used to sterilize food processing equiptments?
per-acetic acid | sporocide- kill bacterial endospores
79
what are surfactants ?
reduce surface tension
80
what are examples of surfactants?
-soaps (degerming agents) -detergents quats- benzalkonium chloride, cetylpyridinium chloride
81
what are the uses for surfactants ?
low-level disinfectants
82
how do surfactants control microorganisms?
disrupts cell membranes
83
what are examples of heavy metals?
Zn, Hg, Ag, Cu
84
what are the uses of heavy metals?
low-level bacteriostatic, fungistatic agents | *static= inhibits growth
85
how do heavy metals kill microorganisms?
denatures proteins and interferes with S groups in proteins.
86
what heavy metal is used to treat ophthalmic gonorrhea ?
1% Soln AgNo3- silver nitrate
87
what heavy metal is used to treat burns?
silver sulfadiazine
88
what heavy metal is used to kill algae in swimming pools?
CuSo4- copper sulfate - algicide=kill
89
what are examples of gaseous agents?
ethylene oxide, propylene oxide, B propiolactone
90
what are the uses of gaseous agents?
high-level disinfectants. | in closed chambers to sterilize items (bed, pillows)
91
how do gaseous agents kill microorganisms?
denatures proteins and DNA by cross-linking functional groups
92
what are the methods used to evaluate the efficiency of disinfectants and antiseptics? describe each...
- phenol coefficient - use-dilution test - kelsey-sykes capacity test(standard method in european countries) - in-use test (most effective) - disk-diffusion method:filter paper, zone of inhibiton...
93
zone of clearing = ?
no growth
94
examples of in-use test
control: counter without backdown treated: counter with backdown
95
tincture of iodine =?
halogen
96
mercorochrome = ?
heavy metal

microbiology exam 2 (4 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions