Lab Final Flashcards
(97 cards)
1
Q
describe a complex culture media…
A
-exact composition is NOT known
-made from meat and soybean extract
2
Q
describe a enrichment culture media…
A
-has extra growth factors to support the organisms with special nutritional needs
3
Q
describe a differential culture media…
A
-has pH indicators; allows for different organisms to be distinguished by changing color
4
Q
describe a selective culture media…
A
-has special chemicals that stimulate growth of some bacteria while inhibiting the growth of others
5
Q
spherical shaped bacteria are called
A
coccus; cocci
6
Q
rod shaped bacteria are called
A
bacillus; bacilli
7
Q
helical & curved bacteria are called
A
vibrio, spirillum, spirilli, spirochetes
8
Q
diplo means
A
there are 2 bacterium
9
Q
tetrad means
A
that are 4 bacterium
10
Q
strepto means
A
the bacterium is in a line formation
11
Q
staphylo means
A
there is a clump/cluster of bacterium
12
Q
coccobacillus means
A
the bacterium is oval shaped
13
Q
vibrio means
A
the bacterium is curved
14
Q
spiral means
A
complete 360 turn
15
Q
define antiseptic
A
a chemical agent that is used in association with the skin and mucous membranes to destroy microorganisms or inhibit their growth
16
Q
define disinfectant
A
a chemical agent that is used on inanimate objects to destroy microorganisms
17
Q
define antibiotics
A
natural, semisynthetic, and synthetic chemicals that inhibit the growth of other microorganisms
18
Q
define aerobe
A
cannot grow w/o oxygen
19
Q
define anaerobe
A
cannot tolerate oxygen
20
Q
define facultative anaerobe
A
prefer to use O2 but when absent will use other alternatives
21
Q
define a psychrophile
A
organism with an optimal growth temp. range of -5 degree C to 20 degrees C
cold loving
22
Q
define mesophiles
A
organisms with an optimal growth temp. range at 20 degrees C to 50 degrees C
23
Q
define thermophiles
A
organisms with an optimal temp. growth range of 50 degrees C to 80 degrees C
24
Q
define halophiles
A
bacterium that require higher salt concentrations to grow
25
define acidophiles
organism with the optimal growth range of pH 5.5 or below
26
define a alkaliphile
organism with the optimal growth range greater than 8
27
define an indicator organism
test that ONLY tests for one kind of organism
28
describe coliforms
- gram negative
- non-endospore forming bacillus
- ferments lactose w/ gas production
- facultative anaerobe
29
what does MPN stand for?
most probable #
30
define potable
water that is deemed safe to drink
31
define transient flora
microorganisms that are acquired from the environment
32
define resident flora
microorganisms that are always found on the body
33
define broad spectrum
an agent that exerts an effect against many different organisms
34
define narrow spectrum
an agent that exerts an effect against only a few organisms
35
define transformation
the transfer of genes from the environment
36
what are the steps in gram staining?
crystal violet
grams iodine
95% ethyl alcohol
safranin
37
in the T-streak procedure and pour plate procedures, why is the loop sterlized?
to reduce the # of cultures in each section of the T-streak, helps to increase the chances of having an isolated culture
38
Why are agar plates inverted during incubation?
to minimize/prevent the accumulation of condensation which could compromise an isolated culture
39
what chemical properties influence diffusion into agar
molecular weight
hydrophobicity
volatility
40
why are zones of inhibition compared to a standard table to determine an organism’s sensitivity?
b/c antibiotics are used internally. Accounts for absorption, digestion, metabolism, and excretion of the antibody in humans/ animals.
| ADME
41
what is the autoclave temperature and pressure?
15 psi
121 degrees Celsius
42
why is an autoclaved used?
b/c boiling will not remove endospores due to their thick cell walls
43
in part 1 of coliform testing the presumptive test was done by
inoculating the lactose broth in a Durham tube
44
part 2 of coliform testing also known as the confirmed test was done by
taking a positive sample and streaking it on EMB
45
EMB is differential for
lactose fermentation
46
Lac+ results in
dark red colonies
47
EMB is selective for
gram-negative bacteria
48
formula to calculate VC/mL
(# of colonies/ vol. of sample) x dilution factor
49
The standard plate count is used to determine…
the # of viable bacteria per mm
50
formula to determine the total magnification
objective * 10X
51
Oxidase Test
tested for:
positive test:
negative test:
- presence of cytochrome oxidase
- blue color when oxidase reagent is added
- no color change
52
Catalase Test
tested for:
positive test:
negative test:
- catalase enzyme
- bubbles when peroxide is added
- no change when peroxide is added
53
what is used for carbohydrate fermentation?
4 tubes
- glucose
- lactose
- sucrose
- mannitol
54
carbohydrate fermentation produces
acid and/or gas
55
what is the indicator found in the test tubes for carbohydrate fermentation? what color changes indicate acid and alkaline condition?
phenol red
- acid: yellow
- alkaline: pink
56
Hemolysis Test
tested for:
positive test:
negative test:
- hemolysin
- zone of clearing
- no zone of clearing
57
beta-hemolysis indicates
complete clearing of blood around colonies
58
alpha-hemolysis indicates
partial clearing of blood around colonies
59
positive result for H2S production is
a black precipitate
60
what medium is used to determine the production of H2S?
SIM medium
61
Urea Hydrolysis
tested for:
positive test:
negative test:
- urease
- hot pink
- yellow-orange
| yellow-orange is the initial color
- a negative result would be no color change
62
Coagulase Test
tested for:
positive test:
negative test:
- clotting of plasma
- clot
- no clot
63
Starch Hydrolysis
tested for:
positive test:
negative test:
- amylase
- zone of clearing after addition of grams iodine
- no zone of clearing
64
Citrate Test
tested for:
positive test:
negative test:
- citrate
- bright blue
- green
| blue at alkaline pH
green at neutral pH
65
MSA test is selective for ____ and differential for _________.
- halophiles
- mannitol fermentation (yellow)
66
EMB test is selective for ____ and differential for _________.
- gram negatives
- lactose fermentation
67
BAP test is differential for
- hemolysins enzymes
68
describe the effect of elevated temperatures on proteins
they are denatured by any temp. above their maximum growth range
- it is irreversible
- the proteins unfolds an will NEVER return to its original shape
69
describe the effect on organisms in temperatures below the minimum growth range
-proteins are not denatured but the enzymes do NOT work properly
-the cells survive but **CANNOT** grow and reproduce
70
a too acidic or too alkaline pH causes...
irreversible protein denaturation and cell death
71
in hypertonic solutions bacteria will
shrivel and die
72
in hypotonic solutions bacteria will
expand and eventually explode
73
name a facultative halophile
Staphylococcus epidermidis
74
when exposed to UV radiation which organism, S. epi or B. meg, survived the longest? why?
B. meg
- b/c it forms endospores which have thick cell walls that UV light can NOT penetrate
75
which molecule is the target of UV light? How is the damage actually caused?
thymine in DNA
by causing adjacent thymines to interact with one another, forming covalent bonds and creating thymine dimers
76
What are some sources of error that can occur with the filter-paper disk method?
1. deeply inserting disks
2. varying amounts of bacterium on plate
3. not having a round disk
4. measuring zones of inhibition
77
What are some chemical properties that can effect the filter-paper disk method?
- hydrophobicity
- volatility
- mw
78
what media was used in the Kirby-Bauer experiment?
MHA
79
penicillin's mode of action is to..
inhibit cell wall synthesis
80
SxT’s mode of action is to…
inhibit the metabolic pathways
81
polymyxin B mode of action is to..
disrupt the cytoplasmic membrane
82
nalidixic acid mode of action is to..
inhibit nucleic acid synthesis
83
tetracyclines mode of action is to...
inhibit protein synthesis
84
gram reaction & morphology of E. coli
- gram-negative
- coccobacillus
85
gram reaction & morphology of salmonella
- gram negative
- bacilli
86
gram reaction & morphology of proteus
- gram negative
- bacilli
87
gram reaction & morphology of pseudomonas
- gram-negative
- bacillus
88
which organism ferments lactose?
e. coli
89
which organism is urease-positive?
proteus
90
which organism is oxidase-positive
pseudomonas
91
which organism ferments neither glucose or lactose?
salmonella
92
Streptococcus
gram reaction
morphology
arrangement
- gram-positive
- cocci
- strepto (line)
93
Staphylococcus
gram reaction
morphology
arrangement
- gram-positive
- cocci
- staphylo (cluster)
94
Describe the physiological characteristics of Staphylococcus aureus
- beta hemolysis
- ferments mannitol
- positive for coagulase production
95
what organism was used for the bacterial transformation lab?
Acinetobacter calcoaceticus
96
what is streptomycin's mode of action?
to inhibit translation
97
what is bacterial transformation
the transfer of genes from the environment
