BACTERIAL NUTRITION AND BACTERIAL GROWTH Flashcards
(121 cards)
1
Q
lowest temp at w/c the organism can grow
A
Minimum temperature requirement
2
Q
temp at w/c organisms grow best
A
Optimum temperature requirement
3
Q
highest temperature at w/c organisms can grow
A
Maximum temperature requirement
4
Q
Min 0oC
Opt 15 oC
Max 20 oC
A
Psychrophile
5
Q
Min 45 oC
Opt 50 – 60 oC
Max 250 oC
A
Thermophile
6
Q
Min 15 – 20 oC
Opt 20 – 40 oC
Max 45 oC
A
Mesophile
7
Q
normal range of pH
A
7.35-7.45
8
Q
grows in pH below 4
A
Acidophile
9
Q
grows in pH greater than 8
A
Alkalinophile
10
Q
grows in pH 6.5 to 7.5
A
Neutrophile
11
Q
Bacteria often produce [?] that could inhibit their own growth
A
acids
12
Q
To maintain the proper pH, [?] are included in the medium
A
buffers
13
Q
Requires higher osmotic pressure; Not pathogenic
A
Osmophile
14
Q
require higher conc. of salts (30%); live in sea water
A
Halophile
15
Q
Can withstand an environment with high salt concentration (2%)
A
Halotolerant
16
Q
“extreme halophiles”
A
Osmophile
17
Q
“obligate halophiles”
A
Halophile
18
Q
“facultative halophiles”
A
Halotolerant
19
Q
example of Halophile
A
Vibrio parahaemolyticus
20
Q
example of Halotolerant
A
Staphylococcus aureus
21
Q
Major Elements
A
Carbon Hydrogen Oxygen Nitrogen Sulfur
22
Q
Minor Elements
A
Phosphorus Potassium Magnesium Iron Calcium
23
Q
Trace Elements
A
Manganese Cobalt Zinc Copper Molybdenum
24
Q
Growth Factors
A
Purines and Pyrimidine
Amino acids
Vitamins
25
Structural backbone of living matter
CARBON
26
Needed for all organic compounds
CARBON
27
Half of the dry weight of bacteria is made up of
CARBON
28
Used in protein synthesis
Nitrogen and Sulfur
29
Use in DNA and RNA synthesis
Nitrogen and Phosphorus
30
Use of gaseous nitrogen directly from the atmosphere
Nitrogen Fixation
31
Synthesize sulfur containing amino acids and vitamins such as THIAMINE and BIOTIN
Sulfur
32
Synthesis of nucleic acids
Phosphorus
33
Phospholipids of cell membrane
Phosphorus
34
ATP synthesis
Phosphorus
35
Cofactor for enzymes
Phosphorus
36
poisonous to organism
OXYGEN
37
dependent on enzyme systems
OXYGEN
38
inability to convert this element can cause problems
OXYGEN
39
TOXIC FORMS OF OXYGEN
Singlet Oxygen
Superoxide Radicals
Peroxides
Hydroxyl radicals
40
normal molecular form of oxygen in a higher energy state
Singlet Oxygen
41
"superoxide anions"
Superoxide Radicals
42
formed in small amount during respiration
Superoxide Radicals
43
highly unstable
Superoxide Radicals
44
from hydrogen peroxide produced from the neutralization of superoxide radicals
Peroxides
45
most reactive form
Hydroxyl radicals
46
formed in the cytoplasm by ionizing radiation
Hydroxyl radicals
47
GROUPS OF BACTERIA ACCORDING TO OXYGEN REQUIREMENT
AEROBES
ANAEROBES
MICROAEROPHILES
CAPNOPHILES (CAPNEIC)
48
require constant exposure to oxygen
Obligate aerobes
49
primarily anaerobe that can tolerate the presence of oxygen
Facultative aerobes
50
has enzymes that convert toxic oxygen derivatives
AEROBES
51
converts molecular oxygen to hydrogen peroxide
Superoxide dismutase
52
Hydrogen peroxide is still toxic so it is converted to water and oxygen
Catalase
53
requires an envi completely free of oxygen
Obligate anaerobes
54
primarily anaerobe that can tolerate the absence of oxygen
Facultative anaerobes
55
lives in the absence of oxygen
ANAEROBES
56
lacks the enzymes SOD and CAT
ANAEROBES
57
accumulation of toxic oxygen radicals may inhibit growth
ANAEROBES
58
refers to bacteria that requires low concentrations of oxygen (2 – 7%)
MICROAEROPHILES
59
cannot grow in the presence of 20 – 21% oxygen
MICROAEROPHILES
60
cannot grow in the absence of oxygen
MICROAEROPHILES
61
requires higher concentrations of carbon dioxide (3 – 5%)
CAPNOPHILES
62
normal concentration of carbon dioxide (1%)
CAPNOPHILES
63
refers to an increase in bacterial number, not an increase in the size
Bacterial growth
64
mode of reproduction
Binary Fission
65
most common method of reproduction of most bacteria
Binary Fission
66
the interval of time between the successive binary fission of a cell or population
Generation time
67
time required for a cell to divide and its population to double
Generation time
68
GT for S. aureus
15 mins
69
GT for M. tuberculosis
15 hrs
70
GT for T. pallidium
33 hrs
71
depends on the condition the bacteria is in
Generation time
72
optimum condition:
faster GT
73
As a cell divides, the population
increases
74
Numerically this is equal to 2 because one cell divides into two raised to the
number of times the cell divided (generations)
75
GT is useful in determining the [?] before disease symptoms
| appear
amount of time that passes
76
GT is useful in determining the effect of a newly developed [?] on the culture
preservative
77
PHASES OF GROWTH
Lag phase
Log phase
Stationary phase
Decline phase
78
adapting to new environment
Lag phase
79
synthesis of enzyme
Lag phase
80
no growth rate
Lag phase
81
Phase of physiologic youth
Lag phase
82
intense metabolic activity
Lag phase
83
synthesis of enzymes and various molecules
Lag phase
84
undergoes binary fission at the fastest rate
Log phase
85
has the shortest and constant generation time
Log phase
86
"exponential phase"
Log phase
87
phase of balanced growth
Log phase
88
Log phase events:
o symptoms of infection
| o appearance of colonies
89
susceptible to certain antibiotic action
Log phase
90
separate -> manufacturing of cell wall = interruption to antibiotic action
Log phase
91
has the highest number of cell
Stationary phase
92
reproduction = death
Stationary phase
93
"plateau phase"
Stationary phase
94
factors of death in Stationary phase
o nutrient depletion
o pH change
o waste accumulation
o acid production
95
unfavorable envi for growth
production of spores
96
negative exponential growth
Decline phase
97
dead cells > viable cells
Decline phase
98
IN-VITRO ENVIRONMENT
Batch culture system
| Continuous culture system
99
single batch of medium only
Batch culture system
100
no additional nutrients are added
Batch culture system
101
waste products are not removed
Batch culture system
102
“open culture system”
Continuous culture system
103
Addition of nutrients; Removal of waste
Continuous culture system
104
sterile medium is fed into the culture vessel at the same rate as the media containing the organism is removed
Chemostat
105
has a photocell that measures the absorbance or turbidity of the culture in the growth vessel
Turbidostat
106
METHODS OF DETERMINING BACTERIAL GROWTH
DIRECT METHOD
Direct cell count
Plate count
Membrane Filter technique
107
METHODS OF DETERMINING BACTERIAL GROWTH
INDIRECT METHOD
Turbidity
| Determination of Dry weight
108
Petroff-Hausser Counting Chamber
Direct cell count
109
easy, cheap
Direct cell count
110
gives the size and morphology
Direct cell count
111
disadvantage: microbial population must
be fairly large for accuracy because it
require a small volume only
Direct cell count
112
"viable cell counts"
Plate count
113
Simple and sensitive
Plate count
114
Prone to inaccurate counts
Plate count
115
Plate count is expressed in
COLONY FORMING UNITS
| CFU
116
to ensure that some colony counts will be within the range of 30 – 300 colonies; to ensure that some colony counts will be within the range of 30 – 300 colonies
SERIAL DILUTIONS
117
2 methods of Plate count
o Pour Plate Method
| o Spread Plate Method
118
Done on colonies growing on special membrane filters having pores designated to trap bacteria
Membrane Filter technique
119
Measures the amount of light that is
transmitted or absorbed through a
solution
Turbidity
120
Turbidity
Absorbance is DIRECTLY PROPORTIONAL to
bacterial growth
121
Cells growing in liquid medium are collected by centrifugation, washed, dried in the oven and weighed
Dry weight
