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Clinical Bacteriology (LAB) > EX. 8 Bacterial Growth and Nutrition > Flashcards

EX. 8 Bacterial Growth and Nutrition Flashcards

1
Q

Physical factors controlling microbial growth

A

Temperature, Oxygen, pH, and Osmotic conditions

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2
Q

Laboratory incubator is usually set at +35C to +37C

A

Mesophiles

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3
Q

What is required to be incorporated in the culture media ?

A

NaCl

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4
Q

Able to grow over wide ranges of water activity or osmotic concentration

A

Osmotolerant

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5
Q

Requires high levels of sodium chloride, usually above about 0.2M, to grow

A

Halophile

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6
Q

Growth optimum between pH 0 and 5.5

A

Acidophile

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7
Q

Growth optimum between pH 5.5 and 8

A

Neutrophile

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8
Q

Growth optimum between pH 8 and 11.5

A

Alkalophile

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9
Q

Grows well at 0C and has an optimum growth temperature of 15C or lower

A

Psychrophile

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10
Q

Can grow at 0-7C; has an optimum growth temperature between 20 and 30C and maximum around 35C

A

Psychrotroph

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11
Q

Growth optimum around 20-45C

A

Mesophile

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12
Q

Grow at 55C or higher, optimum often between 55 and 65C

A

Thermophile

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13
Q

Has an optimum between 80 and about 113C

A

Hyperthermophile

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14
Q

Completely dependent on atmospheric O2 for growth

A

Obligate aerobe

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15
Q

Grows equally well in presence or absence of O2

A

Aerotolerant anaerobe

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16
Q

Does not require O2 for growth, but grows better in its presence

A

Facultative anaerobe

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17
Q

Require O2 levels below 2-10% for growth and is damaged by atmospheric O2 levels (20%)

A

Microaerophile

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18
Q

Does not tolerate O2 and dies in its presence

A

Obligate anaerobe

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19
Q

Growth more rapid at hydrostatic pressures

A

Barophilic

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20
Q

Chemical requirements for controlling microbial growth

A

Carbon and energy sources, Carbon Dioxide, Inorganic and Organic ions

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21
Q

Requires increased CO2 (5-10%)

A

Capnophiles

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22
Q

Essential elements in all living cells

A

Carbon

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23
Q

Required for the synthesis of enzymes and other cellular proteins as well as nucleic acids

A

Nitrogen

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24
Q

Needed for nucleotides, the nucleic acids RNA and DNA, the energy storage molecule, ATP, and for structural phospholipids of the cell membrane

A

Phosphorus

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25
Q

Essential component of some amino acids from disulfide linkages between different parts of polypeptide chains and contribute to the folding of the chains into the correct secondary and tertiary protein structure

A

Sulfur

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26
Q

Trace elements

A

magnesium, iron, cobalt, phosphate, potassium

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27
Q

Sugar loving

A

Saccharophilic

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28
Q

Can only grow in an environment supplemented with a particular growth facto that is not required by wild strain (protoroph)

A

Auxotroph

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29
Q

Molecular arrangement (vitamin)

A

Cyanocobalamin (B12)

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30
Q

One-carbon metabolism

A

Folic acid

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31
Q

Transfer of acyl group

A

Lipoic acid

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32
Q

Precursor of coenzyme A

A

Pantothenic acid

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33
Q

Amino acid metabolism

A

Pyridoxine (B6)

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34
Q

Precursor of NAD and NADP

A

Niacin (nicotinic acid)

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35
Q

Precursor of FAD and FMN

A

Riboflavin (B2)

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36
Q

Substances that promote growth of the organism and are provided by various body fluids and tissues in vivo and form of yeast extract and blood or blood products in vitro

A

Growth factors

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37
Q

increase in bacterial numbers, not an increase in the size of the individual cells

A

Bacterial Growth

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38
Q

Period of Adaptation

A

Lag Phase

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39
Q

When the cell synthesizes new enzymes, cofactors, and essential metabolic intermediates, and the intercellular pools of nutrients are established

A

Lag Phase

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40
Q

Microorganisms are growing and dividing at the maximal rate possible

A

Logarithmic or exponential phase (Log phase)

41
Q

Usually used in biochemical and physiological studies

A

Logarithmic or exponential phase (Log phase)

42
Q

Rate of growth is constant

A

Logarithmic or exponential phase (Log phase)

43
Q

This phase is “balanced growth” where all cellular constituents are manufactured at constant rates relative to each other

A

Logarithmic or exponential phase (Log phase)

44
Q

The rates of synthesis of cell components vary relative to one another until a new balanced state is reached due to change in nutrient levels or other environmental conditions

A

Unbalanced growth

45
Q

Where culture is transferred from a nutritionally poor medium to a richer one

A

Shift-up

46
Q

There is lag while the cells first construct new ribosomes to enhance their capacity for protein synthesis

A

Shift-up

47
Q

Culture is transferred from a rich medium to a poor one

A

Shift-down

48
Q

There is a lag in growth because cells need time to make the enzymes required for the biosynthesis of unavailable nutrients

A

Shift-down

49
Q

Phase where many important secondary metabolites are produces under the limited nutritional conditions

A

Stationary phase or phase of equilibrium

50
Q

Cells living = Cells dying due to exhaustion of nutrients and the production of toxic metabolic products

A

Stationary phase or phase of equilibrium

51
Q

Population growth eventually ceases

A

Stationary phase or phase of equilibrium

52
Q

Attained by bacteria at a population level of around 10^9 cells per ml

A

Stationary phase or phase of equilibrium

53
Q
  • The result of a genetic response triggered in starving, stationary phase cells
  • Cells become dormant without changes in morphology
  • Once the appropriate conditions are available microbes resume growth
A

Viable but nonculturable (VBC)

54
Q
  • Fraction of microbial population is genetically programmed to die after growth ceases
  • Some cells die and the nutrients the leak enable the eventual growth of those cells in the population that did not initiate cell death
  • Dying cells are thus “altruistic” they sacrifice themselves for the benefit of the large population
A

Programmed cell death

55
Q

Gradually the rate of the cell division stops completely, some of the cells die, so that the number of viable cells is reduced

A

Death phase/ Logarithmic decline phase/ phase of decline/ senescence

56
Q

Incubated in a closed culture vessel with a single batch of medium

A

Batch culture

57
Q

No fresh medium is provided during incubation

A

Batch culture

58
Q

Observed in bacteria able to utilize two different carbon sources

A

Biphasic growth

59
Q

System that can maintain a microbial population in exponential growth, growing at a known rate and constant biomass concentration for extended periods

A

Continuous culture system

60
Q

Constructed so that the rate at which sterile medium is fed into culture vessel is the same as the rate at which the media containing microorganisms is removed

A

Chemostat

61
Q

Possesses and essential nutrient in limiting quantities

A

Chemostat

62
Q

Growth rate is determined by the rate at which new medium is fed into the growth chamber; the final cell density depends on the concentration of the limiting nutrient

A

Chemostat

63
Q

Has a photocell that measures the turbidity (absorbance) of the culture in the growth vessel

A

Turbidostat

64
Q

Flow rate of media through the vessel is automatically regulated to maintain a predetermined turbidty

A

Turbidostat

65
Q

Time required for a cell to divide or population to double

A

Generation/doubling time

66
Q

Generation time for Pseudomonas

A

14 minutes

67
Q

Generation time for Staphylococcus aureus

A

30 minutes

68
Q

Generation time for Mycobacterium tuberculosis

A

15 - 24 hours

69
Q

Generation time for Treponema pallidum

A

33 hours

70
Q

Useful in determining the amount of time that passes before disease symptoms appear in infected individuals

A

Generation/doubling time

71
Q

A direct method used to measure volume of bacterial suspension is placed within a defined area on a microscope slide and are counted

A

Direct microscopic count

72
Q

Advantages to this direct method are:

  • easy, inexpensive, quick
  • gives information about the size and morphology of microorganisms
A

Direct microscopic count

73
Q

A disadvantage to this direct method is that to determine population size accurately, the microbial population must be relative large because only a small volume of the population is sampled

A

Direct microscopic count

74
Q

Specially designed slides have chambers of known depth with an etched grid on the chamber bottom

A

Counting chamber

75
Q

Counting chambers included in Direct microscopic count

A

Breed count method, Petroff-Hausser counting chamber, Hemocytometer, and Electronic cell counter

76
Q

Can be used for counting prokaryotes

A

Petroff-Hausser counting chamber

77
Q

Can be used for both prokaryotes and eukaryotes

A

Hemocytometer

78
Q

For larger microorganisms (protists and yeast)

A

Electronic cell counter (Coulter)

79
Q

A direct method used when quantity of bacteria is very small

A

Filtration/ Membrane filtration technique

80
Q

A direct method where a sample is filtered through a thin membrane filter whose pores are too small to allow bacteria to pass the filter

A

Filtration/ Membrane filtration technique

81
Q

A thin membrane filter used in Filtration/ Membrane filtration technique

A

Black polycarbonate membrane filter

82
Q

A most frequently used direct method of measuring bacterial population

A

Plate count/ Viable cell count

83
Q

A direct method that assumes each live bacterium grows and divides to produce one colony

A

Plate count/ Viable cell count

84
Q

An advantage to this direct method are:

  • measures the number of viable cells
  • simple, sensitive, and widely used in food, water, and soil analysis
A

Plate count/ Viable cell count

85
Q

Disadvantages to this direct method are:

  • low count result if clumps of cells are not broken up
  • takes time for visible colonies to form
A

Plate count/ Viable cell count

86
Q

The hot agar used in ___ may injure or kill sensitive cells

A

Pour-plate technique

87
Q

___ sometimes give higher counts

A

Spread-plate technique

88
Q

This technique begins with a sample being pipetted onto surface of agar plate

A

Spread-plate technique

89
Q

This technique begins with a sample being pipetted into a sterile plate

A

Pour-plate technique

90
Q

A direct method used when the microorganism cannot grow on solid media

A

Most probable number (MPN) method

91
Q

This direct method is based on the fact that the greater the number of bacteria in a sample, the more dilution is needed to reduce the density to the point at which no bacteria are left to grow in the tubes in a dilution series

A

Most probable number (MPN) method

92
Q

An indirect method measured by spectrophotometer (colorimeter)

A

Turbidity/ Spectophotometry

93
Q

An indirect method where as the bacteria multiply in a liquid medium, the medium becomes turbid, or cloudy with cells

A

Turbidity/ Spectophotometry

94
Q

An indirect method where when the concentration of bacteria reaches about 10^7 cells per ml, the medium appears slightly cloudy or turbid

A

Turbidity/ Spectophotometry

95
Q

An indirect method where they measure the amount of a certain metabolic product

A

Metabolic Activity

96
Q

An indirect method used where cells growing in liquid medium are collected by centrifugation, washed, dried in an over, and weighed

A

Dry Weight

97
Q

An indirect method used for filamentous organisms

A

Dry Weight

98
Q

An indirect method that is not time consuming and not very sensitive

A

Dry Weight

99
Q

This direct method is for counting bacteria in milk

A

Breed Count Method

Clinical Bacteriology (LAB) (2 decks)

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