2 - Bacterial Growth and Nutrition Flashcards
1
Q
Substances used in biosynthesis of cellular components and energy production
A
Nutrients
2
Q
gm/L of culture medium
A
Macroelements
3
Q
most important chemical requirement, next to water
A
Carbon
4
Q
required for skeleton or backbone of all organic molecules
A
Carbon
5
Q
50% of phospholipid layer of cell membrane (dry weight)
A
Carbon
6
Q
Obtain carbon by recycling process (breakdown of pre-existing molecules to produce new substances):
A
Chemoheterotrophs
7
Q
Obtain carbon by production from CO2
A
Chemoautotrophs (pathogenic bacteria)
8
Q
14% of phospholipid layer of cell membrane (dry weight)
A
Nitrogen
9
Q
Essential part of amino acids that together form proteins for cellular tasks
A
Nitrogen
10
Q
End products of all pathways for nitrogen assimilation
A
Ammonia (NH3)
11
Q
use of atmospheric or gaseous N for cell synthesis
A
Nitrogen fixation
12
Q
Nitrogen is obtained from (3)
A
- Nitrogen fixation
- Decomposition of nitrogen-containing compounds
- Ammonium ions
13
Q
How does available NH3 diffuse into the bacterial transmembrane channels?
A
As GASEOUS NH3 rather than ionic ammonium (NH4+)
14
Q
Major element in all organic compounds and several inorganic ones
A
Hydrogen
15
Q
Maintains pH, forms H bonds in macromolecules
A
Hydrogen
16
Q
Acts as prime force in oxidation-reduction reactions of respiration
A
Hydrogen
17
Q
8% of phospholipid layer of cell membrane (dry weight)
A
Hydrogen
18
Q
Source of free energy in redox reactions
A
Hydrogen
19
Q
plays an important role in structural and enzymatic functions of the cell
A
oxygen
20
Q
Electron acceptor in anaerobic respiration
A
Oxygen
21
Q
Makes up approximately 20% of the atmosphere
A
Oxygen
22
Q
20% of phospholipid layer of cell membrane (dry weight)
A
Oxygen
23
Q
Major component of carbohydrates, lipids and proteins
A
Oxygen
24
Q
How is Sulfur produced or obtained?
A
As SO4- (superscript) and H2S (subscript)
25
For biosynthesis of amino acids (cysteine, cystine, methionine) and vitamins (thiamine and biotin)
Sulfur
26
Protein structure (for linkages called disulfide bonds)
Sulfur
27
Essential for synthesis of nucleic acids and ATP
Phosphorus
28
Main form of phosphorus and where is it derived?
phosphate; H3PO4
29
Measured in mg/L in culture medium
Microelements
30
What are the Macroelements?
CHONSP
31
What are the Microelements?
CaFe MgK
32
Exist in nature as cations
microelements
33
Contributes to heat resistance and bacterial endospore formation
Calcium
34
Constituent of gram positive cell wall
Calcium
35
Part of cytochromes and a co-factor for enzymes and electron-carrying capacity
Iron
36
Uptake of iron in bacteria ismediated by? This acts to chelate iron and transport it.
Siderophore
37
stabilizes ribosomes and cell membranes
magnesium
38
Serves as cofactor for enzymes, complexes with ATP
Magnesium
39
Protein synthesis and membrane function (function and integrity of ribosomes)
Potassium
40
Measured in ug/L
Trace Elements
41
When trace elements are in excess, they are termed ____ because of their toxicity.
Contaminants
42
Essential for catalysis of reactions and activation of enzymes as co-factors
Trace elements
43
What are the Trace Elements?
ZiCuCOMnMoNi
| Zinc, Copper, Cobalt, Manganese, Molybdenum, Nickel
44
Organic compounds required because they are essential cell components or precursors of such component and cannot be synthesized by the organism
Growth Factors
45
3 classes of growth factors
Amino acids
Purines and pyrimidines
Vitamins
46
make up all or part of enzyme co-factors and only very small amounts sustain growth
Vitamins
47
Growth factor for protein synthesis
Amino acids
48
Growth factor for nucleic acid synthesis
Purines and pyrimidines
49
ATP source of chemoautotrophs (lithoautotrophs)
Inorganic compounds
50
Carbon source of chemoautotrophs (lithoautotrophs)
CO2
51
ATP source of chemoheterotrophs
Organic compounds
52
Carbon source of chemoheterotrophs
Organic compounds
53
ATP source of photoautotrophs and photoheterotrophs
Light
54
Carbon source of photoautotrophs
CO2
55
Carbon source of photoheterotrophs
CO2
56
5 physical requirements of bacteria
TAPOH
Temperature, atmosphere, pH, osmotic pressure, hydrostatic pressure
57
True or False. Temperature affects the type of reproduction of a bacteria.
True
58
True or False. All processes of growth are dependent on chemical reaction that are affected by temperature
True
59
At the most favourable temperatures for growth, the number of cell divisions per hour (growth rate) generally ____ for every increase of __°C
doubles; 10
60
Temp at which it grows best (fastest rate of growth and metabolism)
Optimum temperature
61
Temp at which enzymatic reactions are occurring at maximal possible rate
Optimum temperature
62
Temp at which there is membrane gelling; transport processes are so slow that growth cannot occur
Minimum temperature
63
Temp at which there is protein denaturation and thermal lysis
Maximal temperature
64
Found in colder waters and soil (deep ocean, polar regions, arctic environment) at 0 – 15°C
Psychrophiles
65
Thrive at temperature of 15 – 20°C
Psychrotrophs
66
At refrigerator temperature (4-10°C) they spoil food stored for prolonged periods
Psychrotrophs
67
3 forms of spoilage
1. Mold mycelium
2. Slime on food surface
3. Off taste/off color
68
Thrive at 25 - 40C
Mesophiles
69
Optimal temp for free living mesophiles
30C
70
Optimal temp for pathogenic organisms
37C
71
Upper part mesophiles
Parasitic organisms
72
saprophytic bacteria, fungi, algae and protozoa
Lower part mesophiles
73
Thrive best at 40 - 85C
Thermophiles
74
Found in volcanic areas, compost heaps, hot springs
Thermophiles
75
Most thermophiles are?
Prokaryotes
76
Thrive best at temp greater than 80C
Hyperthermophiles
77
Hyperthermophiles are under?
Archae
78
Grow at hydrothermal vents and at great depths in the oceans (hot springs associated with volcanic activity)
Hyperthermophiles
79
Vital for the metabolic activities of hyperthermophiles
Sulfur
80
Highest temp possible for growth of hyperthermophile
121C
81
Type of bacteria which mostly live in association with warm-blooded animals
Mesophiles
82
Among all groups, this type of bacteria has the widest variation in optimum and maximum temp
Thermophile
83
Prefer moderate temp though they can grow at low temp
Psychrotroph
84
Microorganisms that require some NaCl for growth
Halophiles or halotolerants
85
Marine bacteria are classified as
Halophiles
86
most common cause of seafood poisoning
Vibrio parahemolyticus
87
Vibrio parahemolyticus is a?
Halophile
88
Require as high as 30% salt in solution for growth
Extreme halophile
89
Does not require high salt to grow but can withstand up to 15% salt in solution
Facultative halophile
90
Can stand hypertonic environments whether salt, sugar, or other dissolved solutes
Osmophile
91
Fungi (Saboraud's agar) is classified as?
Osmophile
92
Persists in dry environments, subject to desiccation
Xerophile/xerotolerant
93
What induces sporulation?
Loss of nutrients
94
Normal animal flora found in stool
Clostridium tetani
95
Normally require oxygen for growth
Aerobes
96
Can grow in a standard air atmosphere of 21% oxygen, like molds, Mycobacteria and Legionella
Aerobes
97
Organisms requiring presence of CO2 as in N. Gonorrhoea
Aerobes
98
How do aerobes manage superoxides?
By converting them to hydrogen peroxide via superoxide dismutase
99
Enzyme that dissipates H2O2 into molecular O2 and water
Catalase
100
Enzyme that dissipates O2 into water
Peroxidase
101
Can grow in air temperature and can grow anaerobically.
There is greater growth in the presence of oxygen
Facultative aerobes
102
They obtain their energy via fermentation for anaerobic conditions
Facultative aerobes
103
Facultative aerobes are usually non-pathogenic. True or false?
False
104
Enzymes possessed by facultative aerobes?
Superoxide dismutase
| Catalase
105
Bacteria with varied oxygen tolerance, but is usually poisoned by oxygen
Anaerobes
106
Anaerobes are poisoned by ___ as they are highly susceptible to ROS formation
Oxygen
107
Enzymes lacking in anaerobes
Superoxide dismutase
| Catalase
108
Can use oxygen for energy yielding chemical reactions but cannot withstand a 21% level of oxygen
Microaerophilic
109
Microaerophiles grow best at oxygen levels between?
1 and 15%
110
Tolerates oxygen for a short period of time
Aerotolerant
111
Enzyme present in aerotolerants
Superoxide dismutase
112
Optimum pH range survived by bacteria
6.5 - 7.5
113
Can survive up to pH of 4
Acidophiles
114
Max pH survived by Alkaliphiles
pH 11
115
Regulates internal pH of bacteria
Na+/H+ exchanger
116
Creates acidic environment in vagina
Lactobacillus acidophilus
117
Optimum pH for molds and yeast
5 - 6
118
Optimum pH for protozoa
6.7-7.7
119
Optimum pH for algae
4 - 8.5
120
Examples of chemical buffers added in medium to prevent shifts in pH
Peptone
Amino acids
Phosphate salts
121
Force with which water moves through the cytoplasmic membrane from a solution containing a low concentration of dissolved substances (solutes) to one containing a high solute concentration
Osmotic pressure
122
no net flow of water into or out of the cell and the cell grows normally
isotonic solution
123
Higher solute concentration than the cell cytoplasm; the cell loses water (plasmolysis) and growth is inhibited; the cell shrinks. Ex. Food preservation
Hypertonic solution
124
water flows in and ruptures the cell; the cell swells.
Hypotonic solution
125
Pressure exerted on cells by the weight of the water resting on top of them
Hydrostatic pressure
126
pressure-dependent microbes
Barophiles
127
Type of pressure required by barophiles in order to grow
High pressure
128
Why do barophiles die in low pressure?
Because of gas vesicle formation
129
Culture in glass
In vitro
130
Culture in living cells
In vivo
131
A type of culture media used to determine the precise nutritional requirements of the morg. Its exact composition is KNOWN.
Chemically defined or Synthetic culture media
132
A culture media meant to simulate and improve on the natural environment
Chemically undefined or complex culture media
133
Used in routine laboratory cultivation and the study of HETEROTROPHS
Chemically undefined or complex culture media
134
The ideal solidifying agent
Agar
135
Type of artificial media that contains substrates which inhibit the growth of one group of bacteria while allowing the growth of another.
Selective Media
136
Example of selective media
Mannitol Salt Agar
| has 7.5% salt for staohylococci
137
Allows the separation of different groups of bacteria based on variations in colony size or color using dyes as pH indicators.
Differential Media
138
Examples of differential media
MacConkey Agar
(turns pink in E. coli)
Eosin and Methylene Blue (EMB) Agar
(turns green metallic sheen in lactose formation)
139
Artificial media useful in public health microbiology especially in determining water quality
Selective-differential Media
140
Example of Selective-differential Media
MacConkey Agar
141
Media that favors the growth of a particular species but not the growth of others present in the mixed population
Enrichment
142
Nutrient medium with extra growth factors, such as blood
Enrichment
143
Media in which no inhibitory agent is used to prevent the growth of unwanted organisms
Enrichment
144
Example of Enrichment Media
Blood Agar Plate for gram (+) organisms
145
Used to measure the concentrations of antibiotics and vitamins
Microbiological Assay
146
Measures zone of inhibiton of Abx on the growth of morgs
Microbiological Assay
147
True or False. If zone of inhibition is present, continue giving antibiotic because it is effective in inhibiting the growth of the bacteria
True
148
A method of pure culture isolation that transfers diluted microbial mixture to the center of an agar plate and spread evenly over the surface with a sterile bent (L) glass rod.
Spread Plate
149
The microbial mixture is transferred to the edge of an agar plate with an inoculating loop or swab and then streaked out over the surface in one of several patterns.
Streak Plate
150
Microbial mixture is inoculated at one edge and then streaked consecutive times resulting in thinning and isolation of the colonies
Streak Plate
151
Original sample is diluted several times to reduce the microbial population sufficiently to obtain separate colonies upon plating.
Pour plate
152
Generally, the most rapid cell growth occurs at the ____.
Colony edge
153
Growth in media is slower in the edge or center?
Center
154
An increase in cellular constituents. It is also increase in size and population number or both
Growth
155
4 phases of the growth curve
1. Lag phase
2. Log/exponential phase
3, Stationary phase
4. Death phase
156
Period of adaptation
Lag Phase
157
Period during which the cells, depleted of metabolites and enzymes as the result of the unfavorable conditions that existed at the end of their previous culture history, adapt to their new environment.
Lag Phase
158
True or fasle. Immediately after inoculation, the population remains temporarily unchanged (no apparent cell division occurring)
True
159
True or False. In the Lag Phase, there is only an increase in metabolic activity.
True
160
The greater the size of the inoculum, the shorter the lag phase. True or false.
True
161
Period of rapid growth and multiplication
Log or exponential phase
162
All cells in the log phase are rapidly dividing via?
Binary fission
163
Cells are in their steady state
Log or experimental phase
164
Formula of generation time/doubling time
G = t/n
time per generation
number of generations
165
Phase in which growth has already ceased because of exhausted nutrients, loss of biological space or accumulation of toxic end products.
Stationary Phase
166
In stationary phase, cell count increases but at a greatly diminished rate. True or false?
True.
167
Viable cell count stays CONSTANT in Stationary Phase. True or False?
True
168
In which phase does sporulation occur?
Stationary Phase
169
Viable cell population declines
Decline or Death Phase
170
Number of viable cells decrease geometrically (exponentially), essentially the reverse of growth during the log phase
Death or Logarithmic Decline Phase
171
Measurement of population cell growth in which counting chamber is used. It is inexpensive and easy to use.
Direct Counting
172
Disadvantage of direct counting
Does not distinguish between alive and dead cells
173
Petroff-Hauser, hemocytometer, Coulter counter
Direct counting
174
If plated on a suitable medium, each viable unit grows and forms a colony
Indirect Counting
175
Each colony that can be counted is called a ?
CFU - colony forming unit
176
Determines microbial cell weight
Direct Cell Mass measurement
177
Cells growing in liquid medium are collected by centrifugation, washed, dried in an oven and weighed
Direct Cell Mass measurement
178
Useful in measuring population growth of fungi
Direct Cell Mass measurement
179
Useful in measuring population growth via light absroption
Turbidity
180
True or False. As the population and turbidity increases, more light is scattered and the absorbance reading given by the spectrophotometer decreases
True
181
Done by measuring absorbance of cell suspensions
A standard graph plotter with absorbance versus cell concentration, the cell concentration of the unknown microbial sample can be calculated by measuring the absorbance at the same wavelength
Absorbance and Cell Concentration
182
To ensure continued growth where culture volume and the cell concentration are both kept constant by adding fresh medium at the same rate that used cell-containing medium is removed.
Continuous culture: open system
183
Sterile medium is fed into the culture vessel at the same rate as media containing microorganism is removed. Most stable and effective at lower dilution rates
Chemostat
184
Has photocell that measures the absorbance or turbidity of the culture in growth vessel
Flow rate of media through the vessel is automatically regulated to maintain a predetermined turbidity or cell density
Operates best at high dilution rates
Turbidostats
185
OPEN CULTURE:
Culture medium lacks a limiting nutrient
Has variable dilution rate
Turbidostat
186
Enumeration of bacteria in milk or cellular vaccines
Direct microscopic count
187
Enumeration of bacteria in milk, foods, soil, water, laboratory cultures, etc.
Viable cell count (colony counts)
188
Estimations of large numbers of bacteria in clear liquid media and broths
Turbidity measurement
189
Fast and nondestructive, but cannot detect cell densities less than 10^7 cells per ml
Turbidity measurement
190
Measurement of total cell yield from very dense cultures
Measurement of total N or protein
191
Measurement of Biochemical activity
Microbiological assays
192
Requires a fixed standard to relate chemical activity to cell mass and/or cell numbers
Microbiological assays
193
Measurement of total cell yield in cultures
Measurement of dry weight or wet weight of cells or volume of cells after centrifugation
