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Microbiology > 2 - Bacterial Growth and Nutrition > Flashcards

2 - Bacterial Growth and Nutrition Flashcards

1
Q

Substances used in biosynthesis of cellular components and energy production

A

Nutrients

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2
Q

gm/L of culture medium

A

Macroelements

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3
Q

most important chemical requirement, next to water

A

Carbon

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4
Q

required for skeleton or backbone of all organic molecules

A

Carbon

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5
Q

50% of phospholipid layer of cell membrane (dry weight)

A

Carbon

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6
Q

Obtain carbon by recycling process (breakdown of pre-existing molecules to produce new substances):

A

Chemoheterotrophs

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7
Q

Obtain carbon by production from CO2

A

Chemoautotrophs (pathogenic bacteria)

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8
Q

14% of phospholipid layer of cell membrane (dry weight)

A

Nitrogen

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9
Q

Essential part of amino acids that together form proteins for cellular tasks

A

Nitrogen

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10
Q

End products of all pathways for nitrogen assimilation

A

Ammonia (NH3)

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11
Q

use of atmospheric or gaseous N for cell synthesis

A

Nitrogen fixation

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12
Q

Nitrogen is obtained from (3)

A
  1. Nitrogen fixation
  2. Decomposition of nitrogen-containing compounds
  3. Ammonium ions
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13
Q

How does available NH3 diffuse into the bacterial transmembrane channels?

A

As GASEOUS NH3 rather than ionic ammonium (NH4+)

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14
Q

Major element in all organic compounds and several inorganic ones

A

Hydrogen

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15
Q

Maintains pH, forms H bonds in macromolecules

A

Hydrogen

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16
Q

Acts as prime force in oxidation-reduction reactions of respiration

A

Hydrogen

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17
Q

8% of phospholipid layer of cell membrane (dry weight)

A

Hydrogen

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18
Q

Source of free energy in redox reactions

A

Hydrogen

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19
Q

plays an important role in structural and enzymatic functions of the cell

A

oxygen

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20
Q

Electron acceptor in anaerobic respiration

A

Oxygen

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21
Q

Makes up approximately 20% of the atmosphere

A

Oxygen

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22
Q

20% of phospholipid layer of cell membrane (dry weight)

A

Oxygen

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23
Q

Major component of carbohydrates, lipids and proteins

A

Oxygen

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24
Q

How is Sulfur produced or obtained?

A

As SO4- (superscript) and H2S (subscript)

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25
Q

For biosynthesis of amino acids (cysteine, cystine, methionine) and vitamins (thiamine and biotin)

A

Sulfur

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26
Q

Protein structure (for linkages called disulfide bonds)

A

Sulfur

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27
Q

Essential for synthesis of nucleic acids and ATP

A

Phosphorus

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28
Q

Main form of phosphorus and where is it derived?

A

phosphate; H3PO4

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29
Q

Measured in mg/L in culture medium

A

Microelements

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30
Q

What are the Macroelements?

A

CHONSP

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31
Q

What are the Microelements?

A

CaFe MgK

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32
Q

Exist in nature as cations

A

microelements

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33
Q

Contributes to heat resistance and bacterial endospore formation

A

Calcium

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34
Q

Constituent of gram positive cell wall

A

Calcium

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35
Q

Part of cytochromes and a co-factor for enzymes and electron-carrying capacity

A

Iron

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36
Q

Uptake of iron in bacteria ismediated by? This acts to chelate iron and transport it.

A

Siderophore

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37
Q

stabilizes ribosomes and cell membranes

A

magnesium

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38
Q

Serves as cofactor for enzymes, complexes with ATP

A

Magnesium

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39
Q

Protein synthesis and membrane function (function and integrity of ribosomes)

A

Potassium

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40
Q

Measured in ug/L

A

Trace Elements

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41
Q

When trace elements are in excess, they are termed ____ because of their toxicity.

A

Contaminants

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42
Q

Essential for catalysis of reactions and activation of enzymes as co-factors

A

Trace elements

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43
Q

What are the Trace Elements?

A

ZiCuCOMnMoNi

Zinc, Copper, Cobalt, Manganese, Molybdenum, Nickel

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44
Q

Organic compounds required because they are essential cell components or precursors of such component and cannot be synthesized by the organism

A

Growth Factors

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45
Q

3 classes of growth factors

A

Amino acids
Purines and pyrimidines
Vitamins

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46
Q

make up all or part of enzyme co-factors and only very small amounts sustain growth

A

Vitamins

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47
Q

Growth factor for protein synthesis

A

Amino acids

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48
Q

Growth factor for nucleic acid synthesis

A

Purines and pyrimidines

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49
Q

ATP source of chemoautotrophs (lithoautotrophs)

A

Inorganic compounds

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50
Q

Carbon source of chemoautotrophs (lithoautotrophs)

A

CO2

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51
Q

ATP source of chemoheterotrophs

A

Organic compounds

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52
Q

Carbon source of chemoheterotrophs

A

Organic compounds

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53
Q

ATP source of photoautotrophs and photoheterotrophs

A

Light

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54
Q

Carbon source of photoautotrophs

A

CO2

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55
Q

Carbon source of photoheterotrophs

A

CO2

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56
Q

5 physical requirements of bacteria

A

TAPOH

Temperature, atmosphere, pH, osmotic pressure, hydrostatic pressure

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57
Q

True or False. Temperature affects the type of reproduction of a bacteria.

A

True

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58
Q

True or False. All processes of growth are dependent on chemical reaction that are affected by temperature

A

True

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59
Q

At the most favourable temperatures for growth, the number of cell divisions per hour (growth rate) generally ____ for every increase of __°C

A

doubles; 10

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60
Q

Temp at which it grows best (fastest rate of growth and metabolism)

A

Optimum temperature

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61
Q

Temp at which enzymatic reactions are occurring at maximal possible rate

A

Optimum temperature

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62
Q

Temp at which there is membrane gelling; transport processes are so slow that growth cannot occur

A

Minimum temperature

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63
Q

Temp at which there is protein denaturation and thermal lysis

A

Maximal temperature

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64
Q

Found in colder waters and soil (deep ocean, polar regions, arctic environment) at 0 – 15°C

A

Psychrophiles

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65
Q

Thrive at temperature of 15 – 20°C

A

Psychrotrophs

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66
Q

At refrigerator temperature (4-10°C) they spoil food stored for prolonged periods

A

Psychrotrophs

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67
Q

3 forms of spoilage

A
  1. Mold mycelium
  2. Slime on food surface
  3. Off taste/off color
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68
Q

Thrive at 25 - 40C

A

Mesophiles

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69
Q

Optimal temp for free living mesophiles

A

30C

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70
Q

Optimal temp for pathogenic organisms

A

37C

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71
Q

Upper part mesophiles

A

Parasitic organisms

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72
Q

saprophytic bacteria, fungi, algae and protozoa

A

Lower part mesophiles

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73
Q

Thrive best at 40 - 85C

A

Thermophiles

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74
Q

Found in volcanic areas, compost heaps, hot springs

A

Thermophiles

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75
Q

Most thermophiles are?

A

Prokaryotes

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76
Q

Thrive best at temp greater than 80C

A

Hyperthermophiles

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77
Q

Hyperthermophiles are under?

A

Archae

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78
Q

Grow at hydrothermal vents and at great depths in the oceans (hot springs associated with volcanic activity)

A

Hyperthermophiles

79
Q

Vital for the metabolic activities of hyperthermophiles

A

Sulfur

80
Q

Highest temp possible for growth of hyperthermophile

A

121C

81
Q

Type of bacteria which mostly live in association with warm-blooded animals

A

Mesophiles

82
Q

Among all groups, this type of bacteria has the widest variation in optimum and maximum temp

A

Thermophile

83
Q

Prefer moderate temp though they can grow at low temp

A

Psychrotroph

84
Q

Microorganisms that require some NaCl for growth

A

Halophiles or halotolerants

85
Q

Marine bacteria are classified as

A

Halophiles

86
Q

most common cause of seafood poisoning

A

Vibrio parahemolyticus

87
Q

Vibrio parahemolyticus is a?

A

Halophile

88
Q

Require as high as 30% salt in solution for growth

A

Extreme halophile

89
Q

Does not require high salt to grow but can withstand up to 15% salt in solution

A

Facultative halophile

90
Q

Can stand hypertonic environments whether salt, sugar, or other dissolved solutes

A

Osmophile

91
Q

Fungi (Saboraud’s agar) is classified as?

A

Osmophile

92
Q

Persists in dry environments, subject to desiccation

A

Xerophile/xerotolerant

93
Q

What induces sporulation?

A

Loss of nutrients

94
Q

Normal animal flora found in stool

A

Clostridium tetani

95
Q

Normally require oxygen for growth

A

Aerobes

96
Q

Can grow in a standard air atmosphere of 21% oxygen, like molds, Mycobacteria and Legionella

A

Aerobes

97
Q

Organisms requiring presence of CO2 as in N. Gonorrhoea

A

Aerobes

98
Q

How do aerobes manage superoxides?

A

By converting them to hydrogen peroxide via superoxide dismutase

99
Q

Enzyme that dissipates H2O2 into molecular O2 and water

A

Catalase

100
Q

Enzyme that dissipates O2 into water

A

Peroxidase

101
Q

Can grow in air temperature and can grow anaerobically.

There is greater growth in the presence of oxygen

A

Facultative aerobes

102
Q

They obtain their energy via fermentation for anaerobic conditions

A

Facultative aerobes

103
Q

Facultative aerobes are usually non-pathogenic. True or false?

A

False

104
Q

Enzymes possessed by facultative aerobes?

A

Superoxide dismutase

Catalase

105
Q

Bacteria with varied oxygen tolerance, but is usually poisoned by oxygen

A

Anaerobes

106
Q

Anaerobes are poisoned by ___ as they are highly susceptible to ROS formation

A

Oxygen

107
Q

Enzymes lacking in anaerobes

A

Superoxide dismutase

Catalase

108
Q

Can use oxygen for energy yielding chemical reactions but cannot withstand a 21% level of oxygen

A

Microaerophilic

109
Q

Microaerophiles grow best at oxygen levels between?

A

1 and 15%

110
Q

Tolerates oxygen for a short period of time

A

Aerotolerant

111
Q

Enzyme present in aerotolerants

A

Superoxide dismutase

112
Q

Optimum pH range survived by bacteria

A

6.5 - 7.5

113
Q

Can survive up to pH of 4

A

Acidophiles

114
Q

Max pH survived by Alkaliphiles

A

pH 11

115
Q

Regulates internal pH of bacteria

A

Na+/H+ exchanger

116
Q

Creates acidic environment in vagina

A

Lactobacillus acidophilus

117
Q

Optimum pH for molds and yeast

A

5 - 6

118
Q

Optimum pH for protozoa

A

6.7-7.7

119
Q

Optimum pH for algae

A

4 - 8.5

120
Q

Examples of chemical buffers added in medium to prevent shifts in pH

A

Peptone
Amino acids
Phosphate salts

121
Q

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

A

Osmotic pressure

122
Q

no net flow of water into or out of the cell and the cell grows normally

A

isotonic solution

123
Q

Higher solute concentration than the cell cytoplasm; the cell loses water (plasmolysis) and growth is inhibited; the cell shrinks. Ex. Food preservation

A

Hypertonic solution

124
Q

water flows in and ruptures the cell; the cell swells.

A

Hypotonic solution

125
Q

Pressure exerted on cells by the weight of the water resting on top of them

A

Hydrostatic pressure

126
Q

pressure-dependent microbes

A

Barophiles

127
Q

Type of pressure required by barophiles in order to grow

A

High pressure

128
Q

Why do barophiles die in low pressure?

A

Because of gas vesicle formation

129
Q

Culture in glass

A

In vitro

130
Q

Culture in living cells

A

In vivo

131
Q

A type of culture media used to determine the precise nutritional requirements of the morg. Its exact composition is KNOWN.

A

Chemically defined or Synthetic culture media

132
Q

A culture media meant to simulate and improve on the natural environment

A

Chemically undefined or complex culture media

133
Q

Used in routine laboratory cultivation and the study of HETEROTROPHS

A

Chemically undefined or complex culture media

134
Q

The ideal solidifying agent

A

Agar

135
Q

Type of artificial media that contains substrates which inhibit the growth of one group of bacteria while allowing the growth of another.

A

Selective Media

136
Q

Example of selective media

A

Mannitol Salt Agar

has 7.5% salt for staohylococci

137
Q

Allows the separation of different groups of bacteria based on variations in colony size or color using dyes as pH indicators.

A

Differential Media

138
Q

Examples of differential media

A

MacConkey Agar
(turns pink in E. coli)
Eosin and Methylene Blue (EMB) Agar
(turns green metallic sheen in lactose formation)

139
Q

Artificial media useful in public health microbiology especially in determining water quality

A

Selective-differential Media

140
Q

Example of Selective-differential Media

A

MacConkey Agar

141
Q

Media that favors the growth of a particular species but not the growth of others present in the mixed population

A

Enrichment

142
Q

Nutrient medium with extra growth factors, such as blood

A

Enrichment

143
Q

Media in which no inhibitory agent is used to prevent the growth of unwanted organisms

A

Enrichment

144
Q

Example of Enrichment Media

A

Blood Agar Plate for gram (+) organisms

145
Q

Used to measure the concentrations of antibiotics and vitamins

A

Microbiological Assay

146
Q

Measures zone of inhibiton of Abx on the growth of morgs

A

Microbiological Assay

147
Q

True or False. If zone of inhibition is present, continue giving antibiotic because it is effective in inhibiting the growth of the bacteria

A

True

148
Q

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.

A

Spread Plate

149
Q

 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.

A

Streak Plate

150
Q

Microbial mixture is inoculated at one edge and then streaked consecutive times resulting in thinning and isolation of the colonies

A

Streak Plate

151
Q

Original sample is diluted several times to reduce the microbial population sufficiently to obtain separate colonies upon plating.

A

Pour plate

152
Q

Generally, the most rapid cell growth occurs at the ____.

A

Colony edge

153
Q

Growth in media is slower in the edge or center?

A

Center

154
Q

An increase in cellular constituents. It is also increase in size and population number or both

A

Growth

155
Q

4 phases of the growth curve

A
  1. Lag phase
  2. Log/exponential phase
    3, Stationary phase
  3. Death phase
156
Q

Period of adaptation

A

Lag Phase

157
Q

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.

A

Lag Phase

158
Q

True or fasle. Immediately after inoculation, the population remains temporarily unchanged (no apparent cell division occurring)

A

True

159
Q

True or False. In the Lag Phase, there is only an increase in metabolic activity.

A

True

160
Q

The greater the size of the inoculum, the shorter the lag phase. True or false.

A

True

161
Q

Period of rapid growth and multiplication

A

Log or exponential phase

162
Q

All cells in the log phase are rapidly dividing via?

A

Binary fission

163
Q

Cells are in their steady state

A

Log or experimental phase

164
Q

Formula of generation time/doubling time

A

G = t/n
time per generation
number of generations

165
Q

Phase in which growth has already ceased because of exhausted nutrients, loss of biological space or accumulation of toxic end products.

A

Stationary Phase

166
Q

In stationary phase, cell count increases but at a greatly diminished rate. True or false?

A

True.

167
Q

Viable cell count stays CONSTANT in Stationary Phase. True or False?

A

True

168
Q

In which phase does sporulation occur?

A

Stationary Phase

169
Q

Viable cell population declines

A

Decline or Death Phase

170
Q

Number of viable cells decrease geometrically (exponentially), essentially the reverse of growth during the log phase

A

Death or Logarithmic Decline Phase

171
Q

Measurement of population cell growth in which counting chamber is used. It is inexpensive and easy to use.

A

Direct Counting

172
Q

Disadvantage of direct counting

A

Does not distinguish between alive and dead cells

173
Q

Petroff-Hauser, hemocytometer, Coulter counter

A

Direct counting

174
Q

If plated on a suitable medium, each viable unit grows and forms a colony

A

Indirect Counting

175
Q

Each colony that can be counted is called a ?

A

CFU - colony forming unit

176
Q

Determines microbial cell weight

A

Direct Cell Mass measurement

177
Q

Cells growing in liquid medium are collected by centrifugation, washed, dried in an oven and weighed

A

Direct Cell Mass measurement

178
Q

Useful in measuring population growth of fungi

A

Direct Cell Mass measurement

179
Q

Useful in measuring population growth via light absroption

A

Turbidity

180
Q

True or False. As the population and turbidity increases, more light is scattered and the absorbance reading given by the spectrophotometer decreases

A

True

181
Q

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

A

Absorbance and Cell Concentration

182
Q

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.

A

Continuous culture: open system

183
Q

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

A

Chemostat

184
Q

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

A

Turbidostats

185
Q

OPEN CULTURE:
Culture medium lacks a limiting nutrient
Has variable dilution rate

A

Turbidostat

186
Q

Enumeration of bacteria in milk or cellular vaccines

A

Direct microscopic count

187
Q

Enumeration of bacteria in milk, foods, soil, water, laboratory cultures, etc.

A

Viable cell count (colony counts)

188
Q

Estimations of large numbers of bacteria in clear liquid media and broths

A

Turbidity measurement

189
Q

Fast and nondestructive, but cannot detect cell densities less than 10^7 cells per ml

A

Turbidity measurement

190
Q

Measurement of total cell yield from very dense cultures

A

Measurement of total N or protein

191
Q

Measurement of Biochemical activity

A

Microbiological assays

192
Q

Requires a fixed standard to relate chemical activity to cell mass and/or cell numbers

A

Microbiological assays

193
Q

Measurement of total cell yield in cultures

A

Measurement of dry weight or wet weight of cells or volume of cells after centrifugation

Microbiology (7 decks)

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