MICROBIAL GROWTH AND METABOLISM- MICROBIAL CONTROL Flashcards
(132 cards)
1
Q
defined as a process of increase in the number of cells, cell mass and cell activity
A
microbial growth
2
Q
indicators of microbial growth
A
- Increase in both population size and population mass
- Increase in cell number
- Increase in cell mass
- Increase in Metabolic activity
3
Q
most bacteria grow by
A
binary fission
4
Q
The increase in mass is a consequence of
A
Anabolic process
5
Q
main reactions of cell synthesis are
A
polymerization reactions
6
Q
process of regeneration of same type of progeny by parent cell is called as
A
reproductions
7
Q
In microorganisms’ reproduction takes place by
A
sexual, asexual as well by vegetative propagation
8
Q
In case of bacteria, reproduction is defined as ____ of new cells from a parental cell by cell division.
A
regeneration
9
Q
The bacterial cell reproduces or regenerate by four major processes
A
BINARY FISSION
BUDDING
FRAGMENTATION
SPORULATION
10
Q
normal reproductive method of bacteria
A
binary fission
11
Q
single cell divides into two identical cells
A
binary fission
12
Q
process by which most prokaryotes replicate
A
Binary fission
13
Q
generally involves the separation of a single cell into two more or less identical daughter cells, each containing, among other things, at least one copy of the parental DNA
A
Binary fission
14
Q
Most bacteria reproduce by a relatively simple asexual process called
A
binary fission
15
Q
The time interval required for a bacterial cell to divide or
for a population of bacterial cells to double is called
A
generation time
16
Q
Generation times for bacterial species growing in nature
may be as short as __ or as long as __
A
15 minutes
several days
17
Q
parental cell forms a tuber like outgrowth, which after detachment from a parental cell gives rise to new cell with similar phenotypic and genotypic characters
A
BUDDING
18
Q
The bacteria reproduce by budding is
A
Rhodopseudomonas acidophila
19
Q
The yeast reproduce by budding
A
S. cerevisea
20
Q
a mode of asexual reproduction common in filamentous
microorganisms like fungi and filamentous bacteria
A
Fragmentation
21
Q
a small fragment is detached or dissociated from parental filament by mechanical damage
A
reproduction by fragmentation
22
Q
Reproduction by Fragmentation occurs in filamentous cell of a ___ and filamentous fungi like __
A
Nocardia species
Aspergillus spp
23
Q
Cellular events in the cells of certain prokaryotes may change and lead to the formation of new cell types. This type of activity is called
A
differentiation
24
Q
Fragmentation: In bacteria dormant or resting structures of four kinds can be produced:
A
Heat resistant endospores
Exospores
Cysts
Conidia
25
are formed asexually without union of nuclear material from two different types of cells
Heat resistant endospores
26
Kind of heat resistant dormant structures produced by
bacteria and Cyanobacteria which were liberated by mother cell before cell lysis and which giving new vegetative structure after germination
Exospores
27
are formed asexually without union of nuclear material from two different types of cells
Cysts
28
The dormant structure of the fungus like Actinomycetes is a heat labile asexual spore that is formed at the end of special surface (aerial) cells by a process of fragmentation
Conidia
29
a process of formation of endospore inside the vegetative cell in nutrient deficient or adverse conditions.
SPORULATION
30
In some bacteria no internal food reserve, which gain nutrients from exogenous sources for sporulation, such sporulation is called
exogenous sporulation
31
Cell is asymmetrically partitioned by doubled membrane wall called as
spore septum
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Asymmetric cytoplasmic division- Largest one
mother cell
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Asymmetric cytoplasmic division- smallest one
forespore
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Septum does not have
peptidoglycan
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Stage IV: Cortex synthesis- occurs in two sub stages
- deposition of primordial cell wall on inner forespore membrane
- deposition of specific thick layer of peptidoglycan outside the primordial cell wall
36
Dipicolinic acid to Calcium ratio in most of spores
1:1
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In this stage spore become retractile
Stage VI : Maturation
38
Any process, physical or chemical, that will destroy or remove all viable microorganisms (bacteria, fungi, spores, and virus) from an object or from a
particular environment
Sterilization
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Total inactivation of all forms of microbial life in terms of the organism’s ability to reproduce
Sterilization
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Is any cleansing technique that mechanically removes microorganisms or reduce the level of contaminants or microbial population to a safe level as determined by public health standards
Sanitization
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Growth of microorganisms or the presence of microbial toxins in the blood and other tissues
Sepsis
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Any practice that prevents the entry of infectious agents into sterile tissues thus preventing infection
Asepsis
43
Are used to prevent contamination of surgical instruments, medical personnel, and the patient during surgery and also in the food industry
Aseptic techniques
44
Are products/chemical agents used for the asepsis of living tissues applied directly to exposed body surfaces (skin, wounds, mucosa) and surgical incision to destroy or inhibit vegetative pathogens
Antiseptics
45
Applied topically to living tissues
Antiseptics
46
Refers to the use of physical process or chemical agent (disinfectants) that promotes killing, inhibition, or removal of microorganisms (vegetative or growing form) but not the resistant spores of bacteria
Disinfection
47
Is an agent used to reduce the viability of a microbial population below a threshold level that causes infection
Disinfectant
48
Are used on surfaces of inanimate objects (floors, tables)
Disinfectant
49
▪ meaning to kill
▪ Added when a killing action is implied
▪ a suffix indicating that the antimicrobial agent will kill or destroy a certain group of microorganism
Suffix “cide/cidal”
50
An agent that kills certain microorganisms
Germicide
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An agent that kills bacteria. Most do not kill endospores
Bactericide
52
An agent that inactivates viruses
Viricide
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An agent that kills fungi.
Fungicide
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An agent that kills bacterial endospores and of fungal spores
Sporicide
55
▪ meaning to stand still / stop
| ▪ the agent will prevent the growth or multiplication of the type of organism but are not killed outright
Suffix “static/stasis”
56
An agent that inhibits the growth of bacteria, but does not necessarily kill them
Bacteriostatic Agent
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prevents the growth of fungi
Fungistatic agent
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reference standard agent
Phenol
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official method used to test disinfectant potency
Phenol Coefficient Test
60
designed to determine the ratio of the highest dilution of the germicide that will kill the test organism within a specified time to the greatest dilution of phenol showing the same result
Phenol Coefficient Test
61
indicates disinfecting ability compared to that of phenol
Phenol Coefficient Test
62
- most reliable and universally applied method of sterilization
- Whenever possible, should be the method of choice
HEAT
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2 kinds of heat
Dry & Moist
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Refers to minimum time required to kill all microbes at a specified temperature in a specified environment
Thermal Death Time
65
: lowest temperature required to kill all microbes when time is held constant
Thermal Death Point
66
Sterilization that requires higher temperature and longer period of heating
DRY HEAT
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denotes air with a low moisture content that has been heated by flame or electric heating coil
DRY HEAT
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DRY HEAT: Temp. ranges from
160°C – several thousand °C
69
the ultimate sterilization
Incineration
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most widely used type of dry heat
Hot air oven
71
Hot air oven: oven heat set
180 C for 2 hours
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more effective than dry heat, and kills bacteria faster
MOIST HEAT
73
MOIST HEAT: temp ranges from
60-135°C
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Temp and time- Mesophilic non-sporeformers
60°C for 30min
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Temp and time- S. aureus / S. faecalis
60°C for 60mins
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Temp and time- Vegetative form of all bacteria, yeast & fungi
80°C for 5-10mins
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Temp and time- Sporeformers (C. botulinum)
120°C for 4mins
78
can be relied only for disinfection and not for sterilization
Boiling
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is steam under pressure, obtained by heating water in a boiler
Live Steam
80
Tyndallization also called
Fractional / Intermittent sterilization
81
▪ it is used to sterilize heat-sensitive culture media containing materials such as carbohydrates, egg or serum
▪ kills both sporeformer & non-sporeformers
Tyndallization
82
not a reliable method of sterilization
FREEZING
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the formation of ice crystals outside the cell causes the withdrawal of water from the cell interior, resulting in an increased intracellular electrolyte concentration and denaturation of proteins
FREEZING
84
Primarily used in the preservation of bacterial cultures
FREEZING
85
Reduces metabolic rate of most microbes so they cannot reproduce or produce toxins
Bacteriostatic effect
86
defined as energy emitted from atomic activities and dispensed at high velocity through matter or space
RADIATION
87
process of separating microorganism from contaminated solution
FILTRATION
88
an effective method to remove microbes from air and liquids
FILTRATION
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used to prepare liquids that cannot withstand heat, including serum and other blood products, vaccines, drugs, IV fluids, enzymes and culture media
FILTRATION
90
useful for trapping microorganism only
FILTRATION
91
JUST READ
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types of membrane filters:
• Seitz – asbestos – cellulose
• Sintered glass – glass filaments
• Chamberland – unglazed porcelain
• Berkefeld – diatomaceous earth
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92
• Composed of a mat of randomly arranged fibers composed of fiberglass
between 0.5 - 2.0 µm in diameter
• Used to provide a flow of sterile air to hospital /sterile rooms
• Critical in the prevention of the spread of airborne bacterial and viral organisms
• Medical-use hepa filtration systems also incorporate high-energy ultraviolet light units to kill off the live bacteria and viruses trapped by the filter media.
High Efficiency Particulate Air Filters (HEPA)
93
Used to filter most bacteria. Don’t retain spirochetes, mycoplasmas and virus
0.22 and 0.45um Pores
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Retain all viruses and some large proteins
0.1m Pores
95
SONIC VIBRATIONS uses
research laboratories and treating sewage H2O
96
Factors affecting disinfectant potency
1. Number of microorganisms
2. Nature of microorganism
3. Temperature
4. pH
5. Time
6. Mode of action of the agents
7. Concentration of the agent
97
* Substances that alter the energy relationship at interfaces producing a reduction of surface tension
* disrupt the integrity of cell membrane
SURFACE ACTIVE AGENTS
98
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produce electrically (-) colloidal ions in the
solution
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Anionic agents
99
produce electrically (+) ions in the solution
Cationic agents
100
produce electrically neutral colloidal particles
| in the solution; Not effective
Nonionic agents
101
capable of acting either as anionic or cationic detergents
Ampholytic or amphoteric agents
102
two cationic groups separated by a hydrophobic bridging structure
Biguanides
103
at low concentration, these compounds are rapidly bactericidal causing leakage of cell contents and irreversible inactivation of membrane-bound oxidases and dehydrogenases
PHENOLIC COMPOUND
104
Derived from coal tar are used to dissolve other chemicals, as disinfectants and deodorizers, and to make specific chemicals that kill insect pests
Cresols
105
Minimizes concern over the spread of germs in public
| facilities
LYSOL
106
XYLENOLS known as
Dimethylphenols
107
provide an insight into the interaction of organic solvents with
lipid membranes; dehydrate cells, disrupt membranes and cause
coagulation of protein
ALCOHOL
108
penetrate the bacterial cell wall and denature the
| proteins and enzymes inside of the cell
70% conc.
109
coagulates the protein on the outside of the cell wall
| and prevents any alcohol from entering the cell
95% conc.
110
▪ Used as skin disinfectant because of their bactericidal action and ability to remove lipids from the skin surfaces
▪ Unable to kill spores; not relied for sterilization instruments
ETHYL ALCOHOL
111
ETHYL ALCOHOL USES
- to sterilize skin before cutaneous injections
| - to disinfect thermometers
112
Most effective type of alcohol
ISOPROPYL ALCOHOL
113
used in the food and cosmetic industry to prevent growth of microorganisms
o Benzoic acid
o Lactic acid
o Acetic acid
o Propionic acid
114
highly bactericidal for gonococci and routinely used as prophylaxis against opthalmia
neonatorum
Silver nitrate
115
topical cream for burn patients
Silver sulfadiazine
116
very toxic disinfectant, not used today
Mercuric chloride
117
mercury- less toxic but unreliable as skin disinfectant
Metaphen, Merthiolate
| and Mercurochrome
118
is used to kill algae in pools and fish
| tanks
Copper sulfate
119
- Kills fungi and their spores
- Used for fungal infections like Tinea vesicolor infection,
sebborheic dermatitis and dandruff
SELENIUM
120
used in dandruff shampoos (Selsun blue)
Selinium sulfide
121
is used in mouthwashes
Zinc chloride
122
is used as antifungal agent in paints; widely used to treat a variety of other skin conditions, in products such as baby powder and barrier creams to treat diaper
rashes (Desitin) calamine cream, anti-dandruff shampoos, and antiseptic ointments
Zinc oxide
123
are the most significant microbicidal halogens used in the clinic/hospitals and have been traditionally used for
both antiseptic and disinfectant purposes
Chlorine- and iodine-based compounds
124
These are the new broad spectrum disinfectants that highly active against most microorganisms
Hydrogen peroxide
125
the most widely used iodine
povidone-iodine (betadine)
126
widely used as water disinfectant
Chlorine
127
hypochlorites and elemental chlorine + H2O =
hypochlorous acid
128
o widely used for sanitizing dairy products and food processing equipment
o employed as sanitizers in most households, hospitals, and public buildings
o Used as a bleaching agent
Hypochlorite solution
129
Hypochlorite solution marketed as
Chlorox, Zonrox, Purex
130
▪ broad-spectrum efficacy against viruses, bacteria,
yeasts, and bacterial & fungal spores
▪ clear, colorless liquid that is commercially available
in a variety of concentrations ranging from 3 to 90%
Hydrogen peroxide
131
Often referred as Flavines because of their yellow color
Acridine dyes
132
o used as “cold sterilant” for surgical instruments
o 10x more effective than formaldehyde as a bactericidal and sporocidal agent and less toxic
o Less irritating
Glutaraldehyde
