Growth Factor, Oxygen, and Temperature Requirement Flashcards
(314 cards)
1
Q
is a reducing media that takes oxygen from the atmosphere and reduces it to a molecule
A
thioglycollate medium
2
Q
break/liberate things
A
oxidation
3
Q
the loss of electrons during a reaction by a molecule, atom or ion.
A
oxidation
4
Q
a chemical process where a substance gains electrons, effectively decreasing its oxidation state
A
reduction
5
Q
used for anaerobic cultivation
A
candle jar or anaerobic media
6
Q
The need for __, as well as the concentration, varies across
different microorganisms.
A
oxygen
7
Q
Depending on their oxygen requirements,
microorganisms may be classified into (5)
A
aerobes
facultative anaerobes
microaerophiles
aerotolerant anaerobes
obligate (strict) anaerobe
8
Q
organisms that require oxygen for respiration,
grow at the top where oxygen is most plentiful.
A
obligate (strict) aerobes
9
Q
They utilize molecular oxygen
as final electron acceptor during cellular respiration
A
obligate (strict) aerobes
10
Q
grow in the presence or absence of oxygen. When oxygen is available, they
respire aerobically.
A
facultative anaerobes
11
Q
When oxygen is not available, they either respire
anaerobically (reducing sulfur or nitrate instead of oxygen) or ferment an
available substrate.
A
facultative anaerobes
12
Q
facultative anaerobes respire anaerobically, reducing what substances
A
sulfur or nitrate
13
Q
Where an oxygen gradient exists, ___ ___
grow throughout the medium but appear denser near the top
A
facultative anaerobes
14
Q
organisms that do not require oxygen and are not adversely
affected by it, live uniformly throughout the medium
A
aerotolerant anaerobes
15
Q
Aerotolerant anaerobes
are ___even in the presence of free oxygen.
A
fermentative
16
Q
as
the name suggests, survive only in environments containing lower than
atmospheric levels of oxygen
A
microaerophiles
17
Q
n. some microaerophiles called ___can
survive only if carbon dioxide levels are elevated.
A
capnophiles
18
Q
are microorganisms that thrive in the presence of high concentrations of carbon dioxide (CO 2)
A
capnophile
19
Q
example of capnophilic bacteria
A
Neisseria gonorrhoeae
Haemophilus influenzae
Streptococcus pneumoniae
Campylobacter jejuni
Helicobacter pylori
20
Q
___will be seen
somewhere near the middle or upper middle region of the medium
A
microaerophiles
21
Q
are organisms for which even small amounts of
oxygen are lethal and, therefore, will be seen only in the lower regions of the
medium, depending on how far into the medium the oxygen has diffused.
A
obligate anaerobes
22
Q
is a liquid medium designed to promote
growth of a wide variety of fastidious microorganisms.
A
fluid thioglycollate medium
23
Q
It can be used to grow
microbes representing all levels of oxygen tolerance; however, it generally is
associated with the cultivation of anaerobic and microaerophilic bacteria.
A
fluid thioglycollate medium
24
Q
key components of thioglycollate medium
A
yeast extract
pancreatic digest of casein
dextrose
sodium thioglycollate
L-cystine
resazurin
25
components of fluid thioglycollate medium that provide nutrients
yeast extract
pancreatic digest of casein
26
components of fluid thioglycollate medium that reduce oxygen to water
sodium thioglycolate
L-cysteine
27
components of fluid thioglycollate medium that turns pink when oxidized, colorless when reduced
resazurin
28
resazurin, a component of fluid thioglycollate medium, turn ___ when oxidized
pink
29
resazurin, a component of fluid thioglycollate medium, turn ___ when reduced
colorless
30
indicator in fluid thioglycollate medium
resazurin
31
in fluid thioglycollate medium, A small amount of __is
included to slow oxygen diffusion and stabilize growth.
agar
32
in fluid thioglycollate medium, A small amount of __is
included to ___ and ___
slow oxygen diffusion
stabilize growth
33
As mentioned in the
introduction to aerotolerance, oxygen removed during ___will diffuse
back into the medium as the tubes cool to room temperature.
autoclaving
34
As mentioned in the
introduction to aerotolerance, oxygen removed during ___will diffuse
back into the medium as the tubes cool to ___ ___.
room temperature
35
This produces
a gradient of concentrations from fully aerobic at the top to anaerobic at the
bottom
diffusion of oxygen when tube cools down to room temp after autoclaving
36
Thus, fresh media will appear ___to ___ colored with a pink region
at the top where the dye has become oxidized
clear to straw colored
37
Thus, fresh media will appear clear to straw-colored with a __region
at the top where the dye has become oxidized
pink
38
Thus, fresh media will appear clear to straw-colored with a pink region
at the top where the dye has become __
oxidized
39
identify growth in thioglycollate media in fig 9.2 (MIT module 6 guide)
+1
40
is made such that an oxygen gradient concentrates high oxygen (O2) at the top of the broth and low O2 at the bottom of the broth
fluid thioglycollate media
41
organisms that are considered __ will cluster at the top of the thioglycollate media
aerobes
42
organisms that do not like oxygen considered as __ will cluster near the bottom
anaerobic
43
characterizing the growth in fluid thioglycollate media will determine the ___ of the species
aerotolerance
44
The ability to survive in the presence of oxygen
aerotolerance
45
Most aerobes and facultatives that utilize oxygen produce
__ ____, which is toxic to their own enzyme systems.
hydrogen peroxide
46
Most ___ and ___ that utilize oxygen produce hydrogen
peroxide, which is toxic to their own enzyme systems.
aerobes
facultatives
47
Their survival in the
presence of this antimetabolite is possible because they produce an enzyme
called catalase
hydrogen peroxide
48
Their survival in the
presence of this antimetabolite is possible because they produce an enzyme
called ____
catalase
49
converts the hydrogen peroxide to water and oxygen:
catalase
50
draw the rxn between hydrogen peroxide conversion to water and oxygen
2 H2O2 > 2H2O + O2
51
It has been postulated that the death of strict
___in the presence of oxygen may be due to the suicidal act of H2O2
production in the absence of catalase production
anaerobes
52
It has been postulated that the death of strict
anaerobes in the presence of oxygen may be due to the ___act of H2O2
production in the absence of catalase production
suicidial
53
.e presence or absence of
___ production is an important means of differentiation between certain
groups of bacteria.
catalase
54
To determine whether catalase is produced, all that is
necessary is to place a few drops of
3% hydrogen peroxide
55
If the hydrogen peroxide effervesces, the organism is what
catalase positive
56
is designed to identify the presence of cytochrome c
oxidase
oxidase test
57
oxidase test is used to identify the presence of ___
cytochrome c oxidase
58
has the unique
ability to not only oxidize cytochrome c, but to catalyze the reduction of
cytochrome c by a chromogenic reducing agent called tetramethyl-pphenylenediamine
cytochrome c oxidase
59
cytochrome c oxidase has the unique
ability to not only __cytochrome c, but to catalyze the reduction of
cytochrome c by a chromogenic reducing agent called tetramethyl-pphenylenediamine
oxidize
60
cytochrome c oxidase has the unique
ability to not only oxidize cytochrome c, but to catalyze the ___of
cytochrome c by a chromogenic reducing agent called tetramethyl-pphenylenediamine
reduction
61
cytochrome c oxidase has the unique
ability to not only oxidize cytochrome c, but to catalyze the reduction of
cytochrome c by a chromogenic reducing agent called
tetramethyl-pphenylenediamine
62
cytochrome c oxidase has the unique
ability to not only oxidize cytochrome c, but to catalyze the reduction of
cytochrome c by a ___ ___ agent called tetramethyl-pphenylenediamine
chromogenic reducing agent
63
s a substance that changes color when it's oxidized, making it a useful tool in various biological assays,
chromogenic reducing agent
64
When hydrogen peroxide is added to a microbial culture, catalase-___organisms will rapidly break it down, producing visible effervescence (bubbling) due to the release of oxygen gas
positive
65
When hydrogen peroxide is added to a microbial culture, catalase-positive organisms will rapidly break it down, producing visible ___(bubbling) due to the release of oxygen gas
effervescence
66
When hydrogen peroxide is added to a microbial culture, catalase-positive organisms will rapidly break it down, producing visible effervescence (bubbling) due to the release of ___ gas
oxygen gas
67
Acts as the substrate for catalase
hydrogen peroxide
68
concentration of hydrogen peroxide added
3%
69
oxidase test positive
purple color
70
oxidase test negative
no color change
71
This enzyme facilitates the transfer of electrons from cytochrome c to molecular oxygen, leading to the reduction of oxygen and the formation of water.
cytochrome c oxidase
72
The test relies on the ability of this enzyme to catalyze the oxidation of
tetramethyl-p-phenylenediamine (TMPD)
73
TMP means
tetramethyl-p-phenylenediamine (TMPD)
74
if cytochrome c oxidase is present, tetramethyl-p-phenylenediamine (TMPD) is converted to
indophenol
75
characteristic deep purple color if oxidase +
indophenol
76
rxn of oxidase + test
TMPD + e- > Indophenol (purple color)
77
oxidase reagent
1% Tetramethyl-p-phenylenediamine dihydrochloride
78
used when oxidase reagent is placed in this and streaked with a loopful of bacteria
filter paper method
79
are chemicals that develop
color as they become oxidized
chromogenic reducing agents
80
In the ___test, the reducing
reagent is added directly to bacterial growth on solid media, or (more conveniently) a bacterial colony is transferred to paper saturated with the
reagent (Figure 9.4).
oxidase
81
A dramatic color change occurs within seconds if the
___ agent becomes oxidized, thus indicating that cytochrome c oxidase
is present
reducing
82
see the chemistry of the oxidase reaction
+1
83
In terms of nutrition, some microorganisms, whether autotrophic or a
heterotrophic, may require small amounts of certain organic compounds for
growth. These compounds, called
growth factors
84
are essential substances
that some microorganisms cannot synthesize from available nutrients.
growth factors
85
The need for a growth
factor results from either a
blocked or missing metabolic pathway in the cells
86
. Growth factors are organized into three categories:
purines and pyrimidines
amino acids
vitamins
87
required for synthesis of nucleic acids (DNA and
RNA)
purines
pyrimidines
88
required for the synthesis of proteins
amino acids
89
- needed as coenzymes and functional groups of certain enzymes
vitamins
90
example of bacteria that do not require any growth factor
e. coli
91
; they can
synthesize all essential purines, pyrimidines, amino acids and vitamins,
starting with their carbon source, as part of their own ___ ___
intermediary mechanism
92
bacteria that require purines, pyrimidines, vitamins and several amino acid to grow
lactobacillus
93
The growth factors are not metabolized directly as sources of ___ or
energy; rather they are assimilated by cells to fulfill their specific roles in
metabolism
carbon
94
The growth factors are not metabolized directly as sources of carbon or
energy; rather they are assimilated by cells to fulfill their specific roles in
___ (
metabolisms
95
grow best at 20-40°C.
mesophiles
96
example of mesophile
e. coli
97
grow optimally below 15oC
psychrophiles
98
example of psychrophiles
polaromonas vacuolata
99
capable of growth at 0oc
psychrophiles
100
grow optimally at temperatures above
45°C. T
thermophiles
101
example of thermophiles
geobacillus stearotermophilus
102
an grow up to
above 100°C
hyperthermophile
103
example of hyperthermophile
methanopyrus kandleri
104
culture media used in the experiment (growth factor, oxygen, temp requirement)
NA slant
FTM tube
Growth test media A and B
NA plate
105
reagents used in module 6 (gf O2, temp)
3% H2O2
0.5% tetra-methyl-para-phenylene-diamine
hydrochloride (oxidase reagent)
106
Inoculate E. coli, L. bulgaricus, P. cerevisiae, C. sporogenes, and P.
fluorescens to molten FTM (__°C) by stabbing inoculum to the bottom
of the tube using a wire needle. If medium was kept for some time, boil
first and allow to cool.
45oC
107
Inoculate E. coli, L. bulgaricus, P. cerevisiae, C. sporogenes, and P.
fluorescens to molten ___(45°C) by stabbing inoculum to the bottom
of the tube using a wire needle. If medium was kept for some time, boil
first and allow to cool.
fluid thiogylcollate medium
108
Inoculate E. coli, L. bulgaricus, P. cerevisiae, C. sporogenes, and P.
fluorescens to molten FTM (45°C) by stabbing inoculum to the bottom
of the tube using a __ ___. If medium was kept for some time, boil
first and allow to cool.
wire needle
109
Inoculate E. coli, L. bulgaricus, P. cerevisiae, C. sporogenes, and P.
fluorescens to molten FTM (45°C) by stabbing inoculum to the bottom
of the tube using a wire needle. If medium was kept for some time, __
first and allow to cool.
boil
110
2. Mix gently being careful not to ___ the culture.
FTM
aerate
111
Rapidly cool the inoculated tube by dipping in __. Incoulate at 30°C
for 24-48 hrs
FTM
water
112
Rapidly cool the inoculated tube by dipping in water. Incoulate at __°C
for 24-48 hrs
30oC
113
. Inoculate E. coli and L. bulgaricus to NA tubes and incubate at 30°C for
18-24 hrs.
what test
catalase test
114
Add __drops of freshly prepared 3% H2O2.
1-2
115
Growth on __ plates means that the organism does not
require growth factors
both
116
Growth on only ___means growth factors are
required.
GFB
117
media used for temp requirement
NA plates
118
need physical and chemical requirements to
grow.
bacteria
119
In the laboratory, to be able to grow target bacterial
species, one needs to consider the __environments
they are isolated from.
natural
120
Considering these data allows the microbiologist to carry
out ___ of the species of interest
isolation
identification
profiling
121
Chemical Requirements for bacteria
growth factor
oxygen
122
* Physical Requirements for bacteria
temperature
pH
osmotic pressure
123
Organic substances needed by organisms in addition
to carbon and energy sources
amino acids
vitamins
purines pyrimidines
minerals
124
microorganisms utilize amino acids for
protein synthesis
metabolism
adaptation to environmental conditions
125
example of amino acid used by microorganisms
L-glutamic acid
L-lysine
L-threonine
L-phenylalanine
L-tryptophan
126
microorganisms require vitamins for ___ as they act as __ or ___
metabolic functions
coenzymes
precursors
127
example of vitamins that microorganisms use
Vitamin B12
Riboflavin (B2)
Thiamine (B1)
Biotin (B7)
Folic Acid (B9)
128
purines and pyrimidines are used by bacteria as ___
nitrogenous bases in nucleic acid synthesis
129
purines example
adenine
guanine
hypoxanthine
xanthine
130
pyrimidines example
cytosine
thymine
uracil
131
Microorganisms rely on various minerals for
structural integrity
metabolic functions
enzymatic activity
132
minerals used by microbes
iron
magnesium
calcium
potassium
phosphorus
sulfur
133
In bacteria, how much of these are needed?
depending on their metabolic capabilities (some rely on external sources)
134
Auxotrophic bacteriaequire external sources. For example, Lactobacillus species often need L-Glutamic Acid, L-Lysine, and L-Threonine.
amino acids
135
Many bacteria require __as coenzymes. Escherichia coli can synthesize most of these, but others, like Streptococcus, depend on external sources of biotin, riboflavin, and thiamine.
vitamins
136
Essential for nucleic acid synthesis. Fast-growing bacteria like E. coli can synthesize them, while obligate intracellular bacteria (e.g., Chlamydia) rely on host-derived nucleotides.
purines and pyrimidines
137
Required in varying amounts. Iron is crucial for electron transport, magnesium stabilizes ribosomes, and phosphorus is vital for ATP production
minerals
138
GFA means
Growth Factor absent
139
GFB means
growth factor present
140
media are used to determine whether a microorganism requires specific growth factors for survival.
GFA
GFB
141
Lacks essential growth factors like amino acids, vitamins, or purines/pyrimidines. If a bacterium grows on this, it means it can synthesize these compounds independently.
GFA
142
GFB medium contains what
yeast extract or other supplements to provide growth factors
143
Contains yeast extract or other supplements that provide growth factors. If a bacterium grows on this but not on GFA, it indicates a dependency on externally supplied growth factors.
GFB
144
Growth on Both GFA & GFB means
The bacterium does not require external growth factors.
145
Growth Only on GFB means
The bacterium is auxotrophic for certain growth factors.
146
efers to the inability of an organism to synthesize a specific organic compound required for its growth.
auxotrophic
147
No Growth on Either GFA or GFB
The bacterium may require additional nutrients or environmental conditions.
148
example of bacterium that often require external amino acids and vitamins
lactobacillus
149
(cold-loving) can grow at 0oC, and some even
as low as -10oC; their upper limit is often about 25oC.
psychrophiles
150
grow in the moderate temperature range, from
about 20oC (or lower, 10oC) to 45oC to 47oC.
mesophiles
151
are heat-loving, with an optimum growth
temperature of 50o or more, a maximum of up to 70oC or more,
and a minimum of about 20oC
thermophiles
152
have an optimum above 75oC and thus can
grow at the highest temperatures tolerated by any organism.
An extreme example is the genus Pyrodictium, found on
geothermally heated areas of the seabed. It has a temperature
minimum of 82o, optimum of 105o and growth maximum of
110oC.
hyperthermophiles
153
An extreme example of hyperthermophiles
pyrodictium
154
Which state represents all or most
cellular components are
functioning at the maximum rate?
optimum state
155
Thermus aquaticus and Thermococcus litoralis are sources
of:
heat-stable enzymes used in PCR for DNA amplification
156
A heat-resistant enzyme widely used in Polymerase Chain Reaction (PCR) for DNA amplification
Taq DNA Polymerase
157
Thermus aquaticus produces what heat stable enzyme
Taq DNA polymerase
158
Another thermostable polymerase with proofreading activity, making it useful for high-fidelity PCR
Vent DNA polymerase
159
Thermococcus litoralis enzyme
vent DNA polymerase
160
Refers to the measurement of a substance’s acidity or
basicity- relative hydrogen ion concentration.
pH
161
neutrophiles range
6.5-7.5
162
___pH levels can denature proteins, disrupt membrane integrity, and inhibit nutrient transport, limiting bacterial survival.
extreme
163
thrive in acidic environments (pH < 5), such as Lactobacillus in fermented foods.
acidophiles
164
example of acidophiles
lactobacillus
165
prefer neutral pH (6-8), including most human pathogens like Escherichia coli.
neutrophiles
166
grow in basic conditions (pH > 8), such as Bacillus species in soda lakes.
alkaliphiles
167
alkaliphiles examples
bacillus
168
grow in cold environments (<15°C), such as Polaromonas in Arctic ice.
psychrophiles
169
grow in cold environments (<15°C), such as ___in Arctic ice.
polaromonas
170
thrive at moderate temperatures (20-45°C), including most human-associated bacteria.
mesophiles
171
prefer high temperatures (>50°C), such as Thermus aquaticus in hot springs.
thermophiles
172
survive extreme heat (>80°C), like Pyrolobus fumarii in hydrothermal vents.
hyperthermophiles
173
affects enzyme kinetics, membrane fluidity, and metabolic rates.
temperature
174
low temperature effecrt on microorganisms
inhibit bacterial replication
175
high temperature can cause what on microorganisms
cell death
176
hese organisms require high osmotic pressure to grow. They are adapted to environments rich in solutes like sugars or salts
osmophiles
177
example of osmophiles
yeasts and molds
178
these organisms can tolerate high osmotic pressure but do not necessarily require it for growth.
osmotolerant
179
example of osmotolerant species
s. aureus
180
Water acts as a solvent for biomolecules, facilitating molecular interactions, It enables diffusion and transport of nutrients, gases, and signaling molecules within and between cells.
It plays a role in protein folding, ensuring proper structure and function.
what function o fwater
medium of cellular interactions
181
Water participates in hydrolysis reactions, breaking down macromolecules for energy release.
It is involved in redox reactions, maintaining electron flow in biochemical pathways.
Water serves as a substrate and product in metabolic cycles like photosynthesis and respiration.
what function of water
cellular metabolism
182
Water is essential for polymerization reactions, aiding in the synthesis of DNA, proteins, and lipids.
It helps maintain enzyme functionality, stabilizing active sites during biosynthetic processes.
Cellular hydration affects gene expression and metabolic regulation, ensuring efficient synthesis of biomolecules.
what function of water
biosynthesis
183
hich occurred around 2.4 billion years ago, had profound implications for Earth's atmosphere, biosphere, and geological processes.
great oxidation event
184
implication of great oxidation event?
rise of atmospheric oxygen
mass extinction of anaerobic life
formation of banded iron deposits
evolution of aerobic metabolism
185
unstable compound, steals electrons
O2-
186
is an enzyme that catalyzes the dismutation of superoxide radicals into oxygen and hydrogen peroxide
superoxide dismutase
187
C. sporogenes oxygen requirement
obligate anaerobes
188
illustration of growth pattern for c. sporogens in FTM
bottom of the tube
189
E. coli oxygen requirement
facultative anaerobe
190
e.coli growth on FTM
dense growth at surface and diffuse throughout the rest of the tube
191
L. bulgaricus oxygen requirement
aerotolerant anaerobe
192
L. bulgaricus FTM illustration
relative throughout FTM tube
193
P. cerevisiae oxxygen requirement
facultative anaerobe
194
p. cerevisiae growth on FTM
It exhibits
growth
throughout the
medium, with
denser
proliferation in
the upper third
where trace
oxygen is
available.
195
F. fluorescens oxygen requirement
obligate aerobe
196
P. fluorescens growth pattern FTM
top of the medium
197
E. coli
catalase test
catalase positive
198
L. bulgaricus catalase test result
catalase test
199
oxidase test for P.flourescens
positive (deep purple)
200
L. bulgaricus oxidase test
negative (colorless)
201
is a specialized medium designed to create an
oxygen gradient, enabling the growth of microorganisms with varying oxygen
requirements.
fluid thioglycollate medium
202
Explain the different levels of growth in FTM.
Fluid Thioglycollate Medium (FTM) is a specialized medium designed to create an
oxygen gradient, enabling the growth of microorganisms with varying oxygen
requirements. The medium contains sodium thioglycollate to reduce oxygen levels,
agar to limit oxygen diffusion, and resazurin as an oxygen indicator, which turns
pink in the presence of oxygen.
In FTM, obligate aerobes, such as Pseudomonas fluorescens, grow exclusively at
the top of the tube where oxygen is most abundant. Facultative anaerobes like
Escherichia coli grow throughout the tube, thriving in both aerobic and anaerobic
zones but showing denser growth near the surface. Obligate anaerobes, such as
Clostridium sporogenes, grow only at the bottom of the tube where oxygen is
absent. Microaerophiles like Lactobacillus bulgaricus grow just below the surface,
requiring low levels of oxygen but avoiding the fully aerobic zone. Lastly, facultative anaerobic yeasts like Pichia cerevisiae exhibit uniform growth throughout the tube
due to their ability to adapt to both aerobic and anaerobic conditions.
203
Why are bubbles formed when hydrogen peroxide is added to a colony of catalasepositive organisms?
When hydrogen peroxide is introduced to catalase-positive organisms, it
decomposes enzymatically into water and oxygen gas, resulting in bubble
formation. This reaction can be represented as: 2H₂O₂ → 2H₂O + O₂. Through this
process, organisms are protected from the harmful effects of hydrogen peroxide
produced during aerobic metabolism. The bibbling reaction is determined to
distinguish between catalase-positive and catalase-negative bacterial species
204
Why are reactive oxygen species such as hydrogen peroxide harmful to the cell?
Reaction oxygen species (ROS) is a classification that possesses free radicals like
hydroxyl, superoxide anion, singlet, etc., and nitrogen radicals. In the human body,
cell processes mediate slow ROS production that focus on physiological
interactions (Jakubczyk et al 2020). These species can cause damage to
biomolecules (i.e. lipids, proteins, and nucleic acids) due to instability and reactivity.
These molecules are focused on attaining electronic stability which in turn
unselectively targets nearby cells causing a reaction that causes disruption or
stress to cells, thus apoptosis.
205
GFA and GFB growth of P. fluorescens
can grow on both
206
GFA and GFB growth of L. bulgaricus
GFB only
207
p. fluourescens temp requirement
psychotrophic (4-42oC)
208
P. aeruginosa temp growth
mesophile (30-42oC)
209
B subtilis temperature requirement
mesophilic
210
G. stearothermophilis
hyperthermophiles (55oC)
211
Discuss the specific roles of growth factors in bacteria.
Growth factors are essential organic compounds that certain bacteria cannot
synthesize and must obtain from their environment to support growth and metabolism.
These include vitamins, amino acids, purines, and pyrimidines, which serve as
building blocks for biosynthesis or cofactors for enzymatic reactions. Fastidious
bacteria, which have complex nutritional requirements, rely on external sources of
growth factors to support their metabolic activities. Growth factors bind to specific
receptors on the bacterial cell membrane, triggering intracellular signaling cascades
that promote cell division and growth. Additionally, growth factors influence gene
expression and metabolic coordination in bacteria, with growth rate-dependent
feedback mechanisms affecting cellular processes. Understanding the role of growth
factors is essential for cultivating fastidious organisms and studying bacterial
physiology in various environments
212
J. Why are growth factors added in culture media of some but not all bacteria?
Growth factors are added to culture media for bacteria that cannot synthesize
essential nutrients for their growth. These bacteria, known as fastidious organisms,
require specific growth factors such as vitamins, amino acids, or purines for growth
and metabolism. Without the presence of these factors, they would not thrive in the
culture media. Non-fastidious organisms, on the other hand, do not require growth
factor additions as they can synthesize their needed compounds from the basic
nutrients provided in the culture media.
213
K. Discuss the effect of temperature on the metabolic activities of a bacterium.
Temperature significantly impacts the metabolic activities of bacteria in several
ways. As metabolic reaction catalysts, enzymes are highly temperature dependent,
and their increased activity speeds up reaction rates. However, exceeding the optimal
temperature threshold leads to enzyme denaturation and rapid decline. The lipidbased bacterial cell membranes are sensitive to temperature changes; too much heat
compromises the integrity of the membrane, while lower temperatures reduce fluidity.
Bacteria adapt their membrane lipid composition to maintain optimal fluidity, and
growth rates are tightly regulated by temperature. Bacteria are classified based on
their optimal growth temperatures, which significantly impact their populations in
natural and industrial settings.
214
What is the significance of bacteria growing over a wide range of temperature in
their distribution in nature?
Bacteria that grow on a wide temperature range have advantages over natural
distribution since these species can survive and adapt to temperate, hot, and cold
environments that expand ecological niche (i.e. biogeochemical cycles) allowing them
to win over resource that is uninhabitable to other species unfavorable of the said
conditions, thus a more flexible temperature range provides more opportunities to
distribution, survivability, and reproduction
215
Physical factors affecting growth include
pH
temperature
oxygen concentration
moisture
hydrostatic pressure
osmotic pressure
radiation
216
nutritional factors affecting growth
availability of carbon, nitrogen, sulfur, phosphorus, trace elements, and vitamins
217
how bacteria multiply
binary fission
218
one cell becomes two
binary fission
219
cell wall eventually forms a
complete central ___ in binary fission
septum
220
no increase in cell
number in bacterial growth curve
lag phase
221
maximum increase in bacterial growth curve
log phase
222
no net increase in cell number as a result of substrate limitation or inhibition by metabolite accumulation
stationary phase
223
decrease in cell
number owing to toxic
metabolites or substrate
deprivation.
what phase
death phase
224
Most pathogenic
bacteria are
neutrophilic
225
Products of bacterial
metabolism are often what pH
accidic
226
products of bacteria lower/increase pH of growth medium
lower
227
Some bacteria grow at
pH 2 such as those present in what
stomach acid
228
Neutrophile (pH >5.5
and <8)
example
E. coli
229
Neutrophile optimal range
5.5 - 8
230
acidophile optima range
<5.5
231
alkaliphile optima range
>8
232
pH ranges of molds
0.5-11
233
The ultimate pH value of meat is
5.3-5.7
234
Most bacteria grow on pН
7
235
Fungi can grow around pН
2.0-8.0
236
Yeasts can grow around pH
4.0-4.5
237
The ultimate pH of meat is beneficial for the
growth of
yeast and fungi
238
Lactic acid bacteria grows well around pH
5.5-6.0
239
toxic forms of oxygen (5)
singlet oxygen
superoxide free radical
peroxide anion
hydroxyl radical (OH-)
240
is in high energy state & extremely reactive, exists in phagocytes.
singlet oxygen
241
is so toxic to cell, formed in small amount in cellular respiration.
superoxide free radical
hydrogen peroxide
242
used as antimicrobial agent.
peroxide anion
243
the most active form, form in the cytoplasm from respiration.
hydroxyl radical (OH-)
244
is one of several
enzymes that break down peroxide,
a toxic metabolic waste product of
aerobic respiration
peroxidase (catalase)
245
is a common enzyme found in nearly all living organisms
exposed to oxygen.
catalase
246
t catalyzes the decomposition of hydrogen peroxide to water and
oxygen. It is a very important enzyme in protecting the cell from
oxidative damage by reactive oxygen species (ROS).
peroxidase
247
grow in presence of oxygen;
no fermentation;
oxidative phosphorylation
what kind of microorganism
obligate aerobes
248
no oxidative phosphorylation
fermentation
killed by oxygen
lack certain enzymes such as superoxide dismutase, catalse, and peroxidase)
obligate anaerobes
249
is an enzyme that catalyzes the oxidation of various substrates using hydrogen peroxide or other peroxides.
peroxidase
250
rxn of oxygen dismutase and superoxide free radical
O2+2H+ to H₂O2
251
rxn of catalase and hydrogen peroxide
H2O2 > H2O + O2
252
rxn of peroxidase and hydrogen peroxide
H2O2 to H2O / NAD to NADH
253
All fungi and most yeasts growing in meat are
___, except bacteria which can grow in
aerobic, anaerobic or facultative anaerobic
condition.
aerobic
254
Microbes at the surface of meat are have what oxygen requirement.
aerobic
facultative anaerobic
255
Microbes in the inside of meat are what oxygen requirement
anaerobic
facultative anaerobic microbes
256
Vacuum packing or packing can prevent
aerobic microbial activities
257
temperature where enzymes work slower
cold temperature
258
enzymes work best at what temperature
body
259
temperature where enzyme denature, rendering them inactive
high temp
260
0° to 18°C
psycrophiles
261
20°C to 30°C
psychrotroph
262
temperature requirement important in food spoilage
psychrotroph
263
25°C to 45°C
more common
disease causing
mesophile
264
45°C to 70°C
■ Common in hot springs and hot water heaters
thermophiles
265
미 70°C to 110°C
Live at very high temperatures, high enough where water threatens to become
a gas
Usually members of Archaea
Found in hydrothermal vents
hyperthermophiles
266
temperature where it reduces porosity of yeast cell membrane
fewer inhibitory chemicals can enter
low temperatuer
267
temperature that increases porosity of cell membrane, more inhibitory chemicals can enter
high
268
The cooler the temperatures, the ___
fermentation rate.
slower
269
The same yeast fermenting at different
temperatures will create different __.
aromas
270
Non-Saccharomyces yeast tend to be more
cryotolerant than Saccharomyces cerevisiae.
This is why fermentation temperatures for S.
cerevisiae are usually around
20oC
271
Higher temperatures increase the extraction of
__in yeast
polyphenols
272
"pressure that develops when two solutions of
different concentrations are separated by a semipermeable membrane"
osmotic pressure
273
microorganisms require water for growth and are
made up of how many percentage of water
80-90%
274
__ osmotic pressure removes necessary water
from a cell
high
275
is the process where plant and bacterial cells shrink due to water loss into a hypertonic solution, causing the cytoplasm and plasma membrane to separate from the cell wall.
plasmolysis
276
is the bursting or rupturing of a cell, specifically the expulsion of the cell's cytoplasm through a break in the cell wall. This process is also referred to as the localized extrusion of cytoplasm
plasmoptysis
277
inhibits growth i.e.
salt as preservative
what osmotic pressure
high osmotic pressure (hypertonic)
278
cause water to enter and can
cause lysis
what osmotic pressure
low osmotic pressure
279
Bacteria are more tolerant to
osmotic variations because of the
mechanical strength of the ___ __
cell wall
280
no net movement of water
isotonic solution
281
water moves into the cell and may cause
the cell to burst if the wall is weak or
damaged (osmotic lysis)
hypotonic (hypoosmotic) solution
282
water moves out of the cell, causing its
plasma membrane to shrink (plasmolysis)
what osmotic pressure
hypertonic (hyperosmotic)
283
Require moderate to large salt
concentrations. Ocean water contains 3.5% salt.
halophiles
284
___water contains 3.5% salt.
ocean
285
require very high salt concentrations (20 to 30)
extreme or obligate halophiles
286
Do not require high salt
concentrations for growth, but tolerate 2% salt or
more.
facultative halophiles
287
halotolerant example
s. aureus
288
halophile example
v. fischeri
289
All organisms on planet need
___for their metabolic
processes and most will die if
moisture is too little.
water
290
Some bacteria and parasites
can stay dormant in
endospores and cysts until
___is available for their
growth.
moisture
291
Some bacteria and parasites
can stay dormant in
____ and ___ until
moisture is available for their
growth.
endospore
cysts
292
Dissolved substances
such as ___ & ___
interact with water
molecules and make
the water unavailable
to the cell.
salt
sugars
293
Bacteria like __conditions.
Many foods contain liquid
moist
294
Salt removes water by
__like in bacon.
osmosis
295
kills microorganisms by damaging their genetic material, primarily their DNA or RNA.
UV-C light
296
microbes absorb the energy, which leads to the formation of ___ ___—abnormal bonds between adjacent thymine or cytosine bases in their DNA
pyrimidine dimers
297
used for disinfection is most effective
at a wavelength of 264 nm.
UV-C radiation
298
Food is exposed to a carefully measured amount
of intense ionizing radiation.
what process
food irradation
299
When food is irradiated, the __energy
breaks the bonds in the DNA molecules of
microorganism. Thus, the organism dies or
becomes unable to reproduce.
radiation
300
are crucial for microorganisms to
survive in the environment.
nutrients
301
chemical growth factors
carbon
hydrogen
oxygen
nitrogen
phosphorus
sulfur
302
occurs in organic hydrocarbon molecules and in
inorganic molecules such as water.
hydrogen
303
is used in protein/ amino acid synthesis and nucleic acid
polymerization.
nitrogen
304
is essential for nucleic acid synthesis and formation
of phospholipids.
phosphorus
305
present in certain amino acids such as cysteine and
methionine
sulfur
306
Substances in the environment used by
organisms for catabolism and anabolism.
nutrients
307
nutrients required in large amounts,
macronutrients
308
macronutrients include
carbon
oxygen
hydrogen
nitrogen sulfur
309
nutrients that microbes require in small amounts
micronutrients
310
some bacteria requires organic compound
which cannot be synthesized by
themselves. These are called
growth factors
311
major nutritional types of bacteria
energy source
phototrophic
chemotrophic
312
major nutritional types of bacteria
electron source
lithotrophic
313
major nutritional types of bacteria
electron source
organotrophic
314
major nutritional types of bacteria
carbon source
heterotrophic
autotrophic
