Controlling Microbial ( micro para Flashcards

(61 cards)

1
Q

FACTORS THAT AFFECT
MICROBIAL GROWTH

A

Availability of Nutrients
Moisture
Temperature

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2
Q

Microorganisms that grow best at high temperatures are
called

A

thermophiles

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3
Q

Organisms that favor
temperatures above 100°C are referred to as

A

hyperthermophiles

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4
Q

Most microorganisms prefer a what ph

A

neutral or slightly
alkaline growth medium (pH 7.0–7.4)

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4
Q

The highest
temperature at which a bacterium has been found living is
around 113°C; it was an archaeon named

A

Pyrolobus
fumarii.

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5
Q

Microbes that grow best at moderate temperatures are
called

A

mesophiles

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6
Q

prefer cold temperatures.

A

Psychrophiles

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7
Q

prefer warm temperatures
but can endure very cold or even freezing
temperatures.

A

Psychroduric organisms

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8
Q

prefer a pH of >8.5

A

– Alkaliphiles

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8
Q

prefer a pH of 2 to 5

A

– Acidophiles

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9
Q

is the movement of a solvent, through a
permeable membrane, from a lower concentration of
solutes (dissolved substances) to a higher
concentration of solutes.

A

Osmosis

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9
Q

is the pressure that is exerted on a
cell membrane by solutions both inside and outside
the cell

A

Osmotic pressure

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10
Q

When the concentration of solutes in the external
environment of a cell is greater than that of solutes
inside the cell, the solution in which the cell is
suspended is said to be

A

hypertonic.

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10
Q

is a condition in which the cell membrane
and cytoplasm of a cell shrink away from the cell
wall; it occurs when bacteria with rigid cell walls are
placed in a hypertonic solution.

A

Plasmolysis

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10
Q

When the concentration of solutes outside a cell is
less than that of solutes inside a cell, the solution in
which the cell is suspended is said to be

A

hypotonic.

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11
Q

If a bacterial cell is placed into a hypotonic solution,
it may not burst (because of the rigid cell wall). If it
does burst, the cytoplasm escapes; this process is
known as

A

plasmoptysis.

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11
Q

A solution is said to be ___ when the
concentration of solutes outside a cell equals the
concentration of solutes inside the cell.

A

isotonic

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12
Q

Organisms that prefer to live in salty environments
are called

A

halophilic organisms.

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13
Q

Those that do not
prefer to live in salty environments but are capable
of surviving there (e.g., Staphylococcus aureus) are
called .

A

haloduric organisms

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14
Q

Microbes that can survive in high atmospheric
pressure (>14.7 psi) are known as

A

piezophiles.

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15
Q

prefer the same atmosphere that
humans do (~20%–21% O2 and 78%–79% N2, and
<1% other gases)

A

Obligate aerobes

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16
Q

require reduced concentrations of
oxygen (~5% O2).

A

Microaerophiles

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17
Q

require increased concentrations of CO2
(5%–10% CO2).

A

Capnophiles

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17
Q

are killed by the presence of
oxygen

A

Obligate anaerobes

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18
The time it takes for one cell to become two cells is called the
generation time
19
are used in microbiology laboratories to culture (i.e., grow) bacteria
media (sing., medium)
20
A ___ defined medium is one in which all ingredients are known.
chemically
21
an ___ is a broth or solid containing a rich supply of special nutrients that promote the growth of fastidious organisms, for example, chocolate agar
enriched medium
22
A ___ has added inhibitors that discourage growth of certain organisms while allowing the growth of a desired organism, for example, PEA agar.
selective medium
23
A ___ permits the differentiation of organisms that grow on the medium, for example, MacConkey agar
differential medium
24
is a popular liquid medium in bacteriology laboratories; it supports the growth of all categories of bacteria from obligate aerobes to obligate anaerobes.
Thioglycollate (THIO) broth
25
Unwanted organisms are referred to as ____; the growth medium or plate is said to be contaminated
contaminants
26
After media are inoculated, they must be placed into an incubator which will maintain the appropriate atmosphere, temperature, and moisture level; the process is known as
incubation
27
Three types of incubators are used in clinical microbiology laboratories
– A CO2 incubator (contains 5%–10% CO2) – A non-CO2 incubator (contains room air) – An anaerobic incubator (the atmosphere is devoid of oxygen)
28
A ___ can be used to determine growth by measuring the turbidity of the medium.
spectrophotometer
29
are microbes that can survive and multiply only within living cells (called host cells).
Obligate intracellular pathogens
29
A _____ is used to determine the number of viable bacteria in a liquid sample by making serial dilutions of the liquid and inoculating onto nutrient agar; after overnight incubation, the number of colonies is counted.
viable plate count
30
are solutions used to disinfect skin and other living tissues.
Antiseptics
31
Examples of protozoa that can be cultured in vitro are
amebae, Giardia lamblia, Leishmania spp., Toxoplasma gondii, Trichomonas vaginalis, and Trypanosoma cruzi
32
is the destruction or removal of pathogens from nonliving objects by physical or chemical methods; pasteurization is an example of a disinfection technique.
Disinfection
32
is the complete destruction of all microbes, including cells, spores, and viruses
Sterilization
32
are chemical substances that eliminate pathogens on inanimate objects
Disinfectants
33
The suffix -cide or -cidal refers to
“killing.”
33
agents kill bacterial endospores
Sporicidal
34
agents kill fungi, including fungal spores.
Fungicidal
35
agents kill algae.
Algicidal
36
agents destroy viruses.
Viricidal
37
A ___ is a drug or chemical that inhibits growth and reproduction of microbes
microbistatic agent
38
A ____ is one that specifically inhibits the metabolism and reproduction of bacteria.
bacteriostatic agent
39
is a process that combines dehydration (drying) and freezing. this process is widely used in industry to preserve foods, antibiotics, microorganisms, and other biologic materials.
Lyophilization
40
refers to the presence of pathogens in blood or tissues
Sepsis
40
whereas ___ means the absence of pathogens.
asepsis
41
is the prevention of infection.
Antisepsis
42
The _____ of any species is the lowest temperature that will kill all of the organisms in a standardized pure culture within a specified time
thermal death point (TDP)
43
A large metal pressure cooker that uses steam under pressure to completely destroy all microbial life
autoclave
44
—most microorganisms are not killed, but their metabolic activities are slowed
Cold
45
—many dried microorganisms remain viable, but they cannot reproduce.
Desiccation
46
used in hospitals and medical and dental clinics to clean equipment.
Ultrasonic waves
46
an ultra-violet (UV) lamp is useful for reducing the number of microbes in the air.
Radiation
47
used to separate cells/microbes from liquids or gases.
Filters
48
—can be altered to inhibit growth.
Gaseous atmosphere