Micro lab finallll Flashcards
1
Q
enzymes that are active all the time
A
constitutive enzymes
2
Q
enzymes that are active only periodically (when their product is required)
A
Inducible or adaptive enzymes
3
Q
enzyme that acts inside the cell
A
Endoenzyme
4
Q
enzymes that are secreted from the cell and work in the cell’s environment and can reach substrates in agar
A
extracellular enzymes
5
Q
Are enzymes consumed during a reaction?
A
NO
6
Q
Enzyme: Catalase
substrate? products? types of organisms?
A
hydrogen peroxide
water and oxygen gas
All organisms that use oxygen for respiration
7
Q
what does a catalase do?
A
breaks down hydrogen peroxide into water and molecular oxygen
8
Q
Where are catalases located in mammals?
A
Mitochondrial intermembrane space
9
Q
Do anaerobic bacteria make catalase? explain
A
No, they do not produce H2O2 as a byproduct so there is no need to have an enzyme to break it down. They use fermentative metabolism instead.
10
Q
What process generally polymerizes individual subunits into macromolecules?
A
Dehydration synthesis
11
Q
Catalase Positive?
A
Staphylococcus epidermidis
12
Q
Catalase Negative?
A
Streptococcus mutans
13
Q
Enzyme: Cytochrome c Oxidase
Substrate? Products? what type of organisms?
A
reduced form of cytochrome c
H2O or H2O2
All organisms that use oxygen for respiration
14
Q
Cytochrome c Oxidase oxidizes and reduces what
A
oxidizes cytochrome c
reduces molecular oxygen
15
Q
appearance of positive oxidase result?
negative?
A
Positive- purple
negative- no color change
16
Q
Connection between cytochrome c oxidase and catalase?
A
both are made and used by aerobic respiration
cytochrome c oxidase can make H2O2 as a byproduct and catalase is used to detoxify the cell getting rid of the H2O2.
17
Q
Oxidase postive?
A
Pseudomonas putida
18
Q
Oxidase negative?
A
Escherichia coli
19
Q
Cellulose: type of bonds, degraded by?
A
Held by beta (1,4) glycosidic bonds
degraded by cellulase
20
Q
Major structural component of plants
A
cellulose
21
Q
Starch: type of bonds, degraded by?
A
held by alpha (1,4) glycosidic bonds
degraded by amylase
22
Q
reserve food supply for plants
A
amylase
23
Q
commercial uses of amylase
A
detergents, makes glucose and syrup from starch
24
Q
Enzyme: Cellulase
Substate? Product? type of organism?
A
cellulose
glucose monomers
cellulose decomposers in the soil and rotting wood (can be aerobic or anaerobic)
25
Enzyme: Amylase
| Substrate? product? Type of organism?
starch
glucose monomers
cells that use subunits for energy or cell components
26
Appearance of Positive amylase result
Zone of hydrolysis after flooding with iodine
27
Positive for Amylase production?
Bacillus subtilis
28
Negative for amylase production?
Escherichia coli
29
Appearance of Cellulase growth
yellow color
30
chains of amino acids joined together by covalent peptide bonds
proteins
31
short chains of amino acids
peptides
32
Enzyme: Caseinase
| Substrate? products?
Casein
| Peptide chains/ amino acids
33
Type of agar used for caseinase production?
Milk agar
34
Appearance of positive for caseinase
Zone of hydrolysis
35
Positive for Caseinase production?
Bacillus subtilis
36
Negative for Caseinase production?
Escherichia coli
37
Enzyme: Gelatinas
| Substrate? products?
gelatin
| peptide/ amino acids
38
Can some human pathogens produce gelatinase?
YES
39
Appearance of positive for gelatinase production
Zone of hydrolysis
40
Positive for Gelatinase production?
Bacillus subtilis
41
Negative for Gelatinase production?
Escherichia coli
42
What do you flood the plate with for gelatinase production experiment?
dilute HCl
43
Why is gelatin not useful for isolating human pathogens?
Not useful for isolating human pathogens since it becomes liquefied during the 37°C incubation and because some microorganisms produce extracellular proteases that degrade gelatin
44
Heterotroph
gets carbon from the breakdown of an organic compound
45
Autotroph
gets carbon from air (CO2)
46
What is a source of carbon?
sugar
47
what is a process to make ATP?
Fermentation
48
Phototroph
gets energy from light source
49
Chemotroph
organism get energy from chemical source, organic source, or inorganic sources
50
Appearance of acid production
phenol red turns bright yellow
51
Appearance of gas production
bubble in the Durham tube
52
What happens to the pH surrounding an organism when fermentation occurs?
pH decreases
53
Positive result for fermentation
acid and/or gas production
54
Organisms (from the experiment) capable of fermentation (4)
Baciullus cereus
Escherichia coli
Citrobacter freundii
Staphylococcus epidermidis
55
What did Bacillus cereus not ferment?
lactose or sucrose (only glucose)
56
What did E. coli not ferment?
Sucrose (only glucose and lactose)
57
Why can't hydrogen sulfide be detected in a durham tube?
it is extremely soluble in water. We will use the indicator ferric citrate.
58
Examples of Coliforms (3)
E. coli
Citrobacter freundii
Enterobacter aerogenes
59
How can you identify which plate is E. coli and which is Citrobacter freundii?
Do a cysteine desulfhydrase test
60
Appearance of positive cysteine desulfhydrase test
Black line along stab line
61
Positive for cysteine desulfhydrase?
Citrobacter freundii
62
Negative for cysteine desulfhydrase?
Escherichia coli
63
Which type of agar deep do you stab the inoculating needle into for a cysteine desulfhydrase test?
Peptone ion agar deep
64
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Coliforms:
+/-?
endospore/non-endospore forming?
ferments lactose?
Aerobic or anaerobic?
```
negative
non-endospore forming
ferments lactose within 24 hours at 37 degrees C
Aerobic or facultatively anaerobic
65
E. coli appearance on EMB plate
green metallic sheen
66
Enterobacter aerogenes appearance on EMB plate
fish eye colonies
67
Why is enterobacter aerogenes not an indicator organism?
because it can be found naturally in decaying vegetation
68
What enzyme is used in an indole test?
Enzyme tryptophanase breaks down amino acids tryptophan
69
What type of broth is used to test for Indole
1% tryptone broth
70
What is added to the inoculated Tryptone broth to follow up on an indole test?
Kovac's reagent
71
Appearance of positive indole test? Negative?
Red layer that floats on the broth
| colorless or pale orange band appears at the top
72
Methyl red is used to determine is an organism can ferment glucose by what process?
Mixed acid fermentation
73
Appearance of positive methyl red test? Negative?
red color = positive mixed acid fermentation (low/acidic pH)
Yellow color= negative mixed acid fermentation (neutral pH)
74
What does mixed acid fermentation mean?
many acids were produces and pH dropped
75
Vogues-Proskaur is used to determine is an organism can ferment glucose by what process?
butanediol fermentation
76
What do you add to the broth for a VP test?
alpha naphthol and 40% potassium hydroxide (KOH)
77
Appearance of positive VP test
Red color
78
For a citrate test, what is included in the media as a nitrogen source?
Ammonium phosphate
79
Appearance of citrate positive test? Negative
Green slant turns deep blue
| Green slant remains green
80
Why does the slant in a citrate test turn blue?
it is caused by an increase in pH as organism grows and alkaline producers are formed
81
E. coli: +/- for:
| Indole, Methyl Red, VP, Citrate
+, +, -, -
82
Enterobacter aerogenes: +/- for:
| Indole, Methyl Red, VP, Citrate
-, -, +, +
83
energy efficient metabolism in the absence of free oxygen
anaerobic respiration
84
Organisms can use what as an external electron acceptor
sulfate, carbonate, or nitrate ions
85
Series of reactions that reduce nitrate to nitrogen gas
denitrification
86
What if the tube smells like ammonia?
Nitrate was able to reduce to ammonia
87
What if there is gas in the Durham tube? (nitrate reduction)
Nitrate was able to reduce to N2 or N2O
88
What if there is a red color after reagents were added? What are the reagents?
Nitrate was able to reduce to nitrite
| alpha naphthylamine acetate and sulfanilic acid
89
What if there is a red color after adding a few flakes of zinc?
Nitrate was not able to reduce nitrate at all
90
Which organism could reduce nitrate to nitrite?
E. coli
91
Which organism could reduce nitrate to N2 or N2O?
Paracoccus denitrificans
92
Which organism did not reduce nitrate at all?
The control
93
List the steps of Nitrate Reduction in order.
Smell for ammonia
Check for gas bubbles
Add alpha napthylamine acetate and sulfanilic and check for red color
Add flakes zinc and check for red color
94
What are two ways to obtain nitrogen?
Nutrients in the environment
| Gaseous nitrogen from the air
95
What is common to all types of nitrogen fixing bacteria? and what is it?
Nitrogenase enzyme complex
| 2 enzymes that convert gaseous nitrogen into ammonia and then into organic nitrogen
96
What are the two enzymes of nitrogenous enzyme complex?
Dinitrogenase
| Dinitrogenase reductase
97
What uses a third protein that complexes with the nitrogenous enzyme complex to protect it from oxygen inactivation?
Azotobacter
98
Has nitrogen been added to the media in Nitrogen-fixing experiment?
NO
99
Why does the use of mannitol favor Azotobacter growth?
It can rapidly use mannitol as a carbon/energy source while many other organisms cannot.
100
Planting legumes every 4 years to replenish nitrogen in soil
Crop rotation
101
What is added to the nutrient medium for blood agar
5% sterile sheep blood
102
proteins that damage animal cell walls and can cause them to lyse
Hemolysins
103
Alpha hemolysis definition and appearance on blood agar
incomplete lysis of blood cells
| greenish color/darkening around colonies due to methemoglobin
104
Beta hemolysis definition and appearance on blood agar
Complete lysis of red blood cell
| complete clearing around colonies
105
Gamma hemolysis defintion and appearance on blood agar
no hemolysis
| no change around colonies
106
cause tooth decay (alpha hemolysis)
Streptococcus mutans
107
cause strep throat (beta hemolysis)
Streptococcus pyrogenes
108
structures or substances produced by microorganisms that helps ability to form disease
Virulence factor
109
lyses blood cells
hemolysins
110
Dissolves fibrin clots in blood
Streptokinase
111
What does the candle jar incubation facilitates?
optimum growth and production of hemolysins
112
Appearance of Streptococcus mutans on blood agar
dull
113
Appearance of Staphylococcus epidermidis on blood agar
shiny
114
What is produced in homofermentation?
only lactic acid
115
What is produced in heterofermentation?
ethanol, lactic acid, and CO2
116
Do most lactic acid bacteria use peroxidases or catalase to degrade H2O2?
peroxidases
117
one species establishes themselves, followed by another species after growing conditions are rendered ideal
Succession
118
Media that is selective for Lactobacillus due to low pH
MRS media
119
Difference between catalase and peroxidase?
both are used to get rid of toxic hydrogen peroxide but only catalase will have oxygen as a product, peroxidase uses a completely different mechanism
120
recruits new cells to the biofilms and signal all members of the biofilm to form a certain compound simultaneously
Homeserine lactone
121
Adhesion of a few cells to a surface
Attachment
122
Growth, polysaccharide production, cell communication
Colonization
123
objects appear with significant contrast to their surroundings due to differences in refractive index of the specimen
Phase Contrast
124
Light passes though the specimen through the sides only
Dark field
125
A virion is composed of?
nucleic acid, capsid, envelope
126
viruses that infect bacteria
bacteriophages
127
number of plaque forming units per mL
Titer
128
responsible for a large percent of nosocomial infections
Staphylococci
129
Virulence factors of Staphylococcus aureus
B hemolysins and coagulase and exotoxin
130
causes plasma to clot
coagulase
131
surpasses the growth of unwanted organisms while encouraging the growth of specific microbes
selective media
132
Selective component of MSA (Mannitol Salt Agar)
7.5% NaCl
133
differential component of MSA
Mannitol and Phenol Red
134
colonies that ferment mannitol (2)
S. aureus and S. saprophyticus
135
do not ferment mannitol (2)
Staphylococcus epidermidis
136
appearance of positive mannitol fermentation
yellow
137
appearance of negative mannitol fermentation
pale or white on a pink medium
138
any intimate relationship or association of two dissimilar organism
Symbiosis
139
both populations benefit
mutualistic
140
one population benefits, one is unaffected
commensalistic
141
relationship benefits both populations but the association is not necessary for the survival of either species
Synergistic
142
host is harmed, while parasite benefits
parasitic
143
one population produces a substance, which inhibits the growth of another organism's population
Antagonistic
144
cannot grow in the presence of oxygen, do not use oxygen as a final electron acceptor
obligate anaerobe
145
exclusively anaerobic type of metabolism but they are insensitive to the presence of O2
Aerotolerant
146
doing aerobic respiration in the presence of oxygen but also being able to do anaerobic respiration or fermentation when no oxygen is present
Facultative anaerobe
147
requires oxygen for respiration
Aerobic
148
prefer increased carbon dioxide and reduced oxygen tension
microaerophilic
