Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Microbiology > Lesson 13 > Flashcards

Lesson 13 Flashcards

1
Q

______ are ubiquitous and many microorganisms are associated with
undesirable consequences, such as food spoilage and disease. Therefore, it is
essential to kill a wide variety of microorganisms or inhibit their growth to minimize
their destructive effects.

A

Microbes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Microorganisms
The goal is twofold:

A

(a) to destroy pathogens and prevent
their transmission and
(b) to reduce or eliminate microorganisms responsible for the
contamination of water, food, and other substances.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Microorganisms are controlled
either by

A

physical agents (temperature, desiccation, osmotic pressure, radiation, and
filtration)
or
chemical agents (disinfectants, antiseptics, antibiotics, and
chemotherapeutic antimicrobial chemicals)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

: a process by which an article, surface, or medium is freed of all
living microorganisms either in the vegetative or in the spore state.

A

Sterilization

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

: any material that has been subjected to the above process.

A

Sterile

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

: a chemical agent that is used to perform sterilization because of their
ability to destroy spores.

A

Sterilants

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

: also called a microbicide, is any chemical agent that kills pathogenic
microorganisms either on inanimate (nonliving) materials or on living tissue but not
resistant microbial cells.

A

Germicide

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

: the use of a chemical agent that destroys or removes all pathogenic
organisms or organisms capable of giving rise to infection or its harmful products
(toxin) thus destroys vegetative pathogens but not bacterial endospores. Used only
on inanimate objects because they can be toxic to human and other animal tissue,
when used in higher concentrations.

A

Disinfection

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

: is defined as the growth of microorganisms in the body or the presence of
microbial toxins in blood and other tissues.

A

Sepsis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

: refers to any practice that prevents the entry of infectious agents into
sterile tissues and thus prevents infection.

A

Asepsis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

: are chemical agents applied directly to the exposed body surfaces
(e.g., skin and mucous membranes), wounds, and surgical incisions to destroy or
inhibit vegetative pathogens.

A

Antiseptics

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

: is any cleansing technique that mechanically removes
microorganisms (along with food debris) to reduce the level of contaminants.

A

Sanitization

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

: a compound (e.g., soap or detergent) that is used to perform
sanitization. Air sanitization with ultraviolet lamps reduces airborne microbes in
hospital rooms, veterinary clinics, and laboratory installations.

A

Sanitizer

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

: a process usually involves scrubbing the skin or
immersing it in chemicals, or both. It also emulsifies oils that lie on the outer
cutaneous layer and mechanically removes potential pathogens from the outer
layers of the skin. Examples of degerming procedures are (a) surgical hand scrub, (b)
application of alcohol wipes to the skin, and (c) cleansing of a wound with germicidal
soap and water.

A

Degerming/antisepsis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Methods of controlling microorganisms

A
  1. Sterilization
  2. Disinfection
  3. Antimicrobials
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

STERILIZATION
Classified into:

A
  1. Physical methods
  2. Chemical methods
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

: a natural method of sterilization of water in tanks, rivers, and lakes.
Direct sunlight has an active germicidal effect due to its content of ultraviolet and
heat rays. Bacteria present in natural water sources are rapidly destroyed by
exposure to sunlight.

A

Sunlight

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

: one of the most dependable method of sterilization. As a rule, higher
temperatures (exceeding the maximum) are microbicidal, whereas lower
temperatures (below the minimum) tend to have inhibitory or microbiostatic
effects.
Two types: moist and dry heat.

A

Heat

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

occurs in the form of hot water, boiling water, or
steam (vaporized water) and the temperature usually ranges from 60 to
135°C. Moist heat kills microorganisms by denaturation and coagulation of
proteins.

A

Sterilization by moist heat

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

. example is Pasteurization

A

Sterilization at a temperature below 100°C:

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

is a technique in which heat is applied to liquids to kill
potential agents of infection and spoilage, while at the same time
retaining the liquid’s flavor and food value. This method is extensively
used for sterilization of milk and other fresh beverages, such as fruit
juices, beer, and wine which are easily contaminated during collection
and processing.

A

Pasteurization

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Pasteurization has two methods:

A

Flash method
Holder method

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

(product is exposed to heat at 72°C for 15–20 seconds followed by a
sudden cooling to 13°C or lower)

A

Flash method

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

(product is
exposed to a temperature of 63°C for 30 minutes followed by cooling to
13°C or lower, but not less than 6°C).

A

holder method

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

inactivates most viruses and destroys the vegetative stages of
97–99% of bacteria and fungi, it does not kill endospores or thermoduric species
(mostly nonpathogenic lactobacilli, micrococci, and yeasts).

A

Pasteurization

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

is carried out over a period of 3 days and
requires a chamber to hold the materials and a reservoir for boiling water.
Items to be sterilized are kept in the chamber and are exposed to freeflowing steam at 100°C for 20 minutes, for each of the three consecutive
days.

A

Tyndallization

27
Q

Process of Tyndallization

A

1st day: the temperature is adequate to kill all the vegetative forms of the
bacteria, yeasts, and molds but not sufficient to kill spores.
2nd day: The surviving spores are allowed to germinate to vegetative
forms on the second day and are killed on re-exposure to steam.
3rd day: re-ensures killing of all the spores by their germination to
vegetative forms.

28
Q

_______ makes use of air with a low moisture content that has
been heated by a flame or electric heating coil. In practice, the temperature of
dry heat ranges from 160°C to several thousand degrees Celsius. The dry heat
kills microorganisms by protein denaturation, oxidative damage, and the toxic
effect of increased level of electrolytes.

A

Sterilization by dry heat

29
Q

: Sterilization of inoculating loop or wire, the tip of forceps,
searing spatulas, etc., is carried out by holding them in the flame of the
Bunsen burner till they become red hot. Glass slides, scalpels, and
mouths of culture tubes are sterilized by passing them through the
Bunsen flame without allowing them to become red hot.

A

Flaming

30
Q

is an excellent method for safely destroying
infective materials by burning them to ashes.

A

Incineration

31
Q

is electrically heated and is fitted with a
fan to ensure adequate and even distribution of hot air in the chamber. It
is also fitted with a thermostat that ensures circulation of hot air of
desired temperature in the chamber.

A

hot-air oven

32
Q

: remove contaminating microorganisms from solutions rather than
directly destroying them. The filters are of two types: (a) depth filters; ex candle
filter, asbestos filter or sintered glass filters, and (b) membrane filters; ex,
cellulose acetate,cellulose nitrate, polycarbonate,polyvinylidene fluoride, or other
synthetic materials made of membrane filters.

A

Filtration

33
Q

is an excellent sterilizing agent
with very high penetrating power. These radiations penetrate deep into objects
and destroy bacterial endospores and vegetative cells, both prokaryotic and
eukaryotic but not that effective against viruses. Example: (a) X-rays, (b) gamma
rays, and (c) cosmic rays. Gamma radiation from a cobalt-60 source is used for
sterilization of antibiotics, hormones, sutures, catheters, animal feeds, metal foils,
and plastic disposables, such as syringes, meat and other food items. Irradiation
usually kills Escherichia coli O157:H7, Staphylococcus aureus, Campylobacter
jejuni, and other pathogens. Since there is no detectable increase of
temperature in this method, this method is commonly referred to as “cold
sterilization.” Both the Food and Drug Administration and the World Health
Organization have approved food irradiation and declared it safe.

A

Radiations: Ionizing radiations: Ionizing radiation

34
Q

: Use of high-frequency sound (sonic) waves beyond the sensitivity
of the human ear are known to disrupt cells. Sonication transmits vibrations
through a water-filled chamber (sonicator) to induce pressure changes and create intense points of turbulence that can stress and burst cells in the vicinity.
Sonication also forcefully dislodges foreign matter from objects. Heat generated
by the sonic waves (up to 80°C) also appears to contribute to the antimicrobial
action. Gram-negative rods are most sensitive to ultrasonic vibrations, while
Gram-positive cocci, fungal spores, and bacterial spores are resistant to them.

A

Sonication

35
Q

The process of inactivating microorganisms by direct exposure to chemical or
physical agents

A

DISINFECTION

36
Q

are products or biocides that destroy or inhibit the growth of
microorganisms on inanimate objects or surfaces. Disinfectants can be sporistatic
but are not necessarily sporicidal.

A

Disinfectants

37
Q

are biocides or products that destroy
or inhibit the growth of microorganisms in or on living tissue.

A

Antiseptics

38
Q

Properties of ideal disinfectant
.

A
  1. It should have a wide spectrum of antimicrobial activity.
  2. It should act in the presence of organic matter.
  3. It should not be toxic to human or corrosive.
  4. It should be stable upon storage and should not undergo any chemical
    change.
  5. It should be odorless or with a pleasant odor.
  6. It should be soluble in water and lipids for penetration into microorganisms.
  7. It should be effective in acidic as well as in alkaline media.
  8. It should have speedy action.
  9. If possible, it should be relatively inexpensive.
39
Q

Action of Disinfectants

A
  1. They produce damage to the cell wall and alter permeability of the cell
    membrane, resulting in exposure, damage, or loss of the cellular contents.
  2. They alter proteins and form protein salts or cause coagulation of proteins.
  3. They inhibit enzyme action and inhibit nucleic acid synthesis or alter nucleic
    acid molecules.
  4. They cause oxidation or hydrolysis.
40
Q

: Increase in temperature increases the
efficiency of
disinfectants.

A

Temperature

41
Q

are more susceptible than spores.
Spores may be resistant to the action of disinfectants.

A

Type of microorganism: Vegetative cells

42
Q

: Young and metabolically active cells are more
sensitive than old dormant cells. Non growing cells may not be affected.

A

Physiological state of the cell

43
Q

: The physical or chemical properties of the medium or substance
influence rate as well as efficiency of disinfectants, e.g., pH of the medium and
presence of extraneous materials.

A

Environment

44
Q

: most widely used antiseptics and disinfectants in
laboratories and hospitals worldwide. They are bactericidal or bacteriostatic and
some are fungicidal also. They act by denaturing proteins and disrupting cell
membranes. They are effective in the presence of organic material and remain
active on surfaces long after application

A

Phenolic compounds

45
Q

(is effective against
vegetative forms of bacteria but not suitable for application to skin or mucous
membrane),

A

Phenol

46
Q

(are more germicidal and less poisonous than phenol but
corrosive to living tissues. They are used for cleaning floors (1% solution), for
disinfection of surgical instruments, and for disinfection of contaminated objects.
Lysol is a solution of cresols in soap),

A

Cresol

47
Q

compounds (like
hexachlorophene and chlorhexidine are highly effective against both Grampositive and Gram-negative bacteria. They are used as skin antiseptics and for
the cleaning of wound surfaces especially hexachlorophene because once
applied it persists on the skin and reduces growth of skin bacteria for longer
periods. However, it can cause brain damage and is now used in hospital
nurseries only after a staphylococcal outbreak).

A

Halogenated diphenyl

48
Q

are fluorine, bromine, chlorine, and iodine—a group of
nonmetallic elements that commonly occur in minerals, sea water, and salts.

A

Halogens: Halogens

49
Q

not only bacterial cells and endospores but also fungi and viruses.
Chlorination at a concentration of 0.6–1.0 part of chlorine per million parts of
water makes water potable and safe to use. However chlorine is ineffective at
an alkaline pH, less effective in the presence of excess organic matter, and
relatively unstable, if exposed to light. On the other hand, iodine rapidly
penetrates the cells of microorganisms, where it apparently disturbs a variety of
metabolic functions by interfering with the hydrogen and disulfide bonds of
proteins (similar to chlorine). But not adversely affected by organic matter and
pH. The two primary iodine preparations are free iodine in solution and
iodophors (betadine).

A

Chlorine kills

50
Q

rapidly
penetrates the cells of microorganisms, where it apparently disturbs a variety of
metabolic functions by interfering with the hydrogen and disulfide bonds of
proteins (similar to chlorine).

A

iodine

51
Q

The two primary iodine preparations are

A

free iodine in solution and
iodophors (betadine).

52
Q

: most widely used disinfectants and antiseptics effective at a
concentration of 60–70% in water

A

Alcohols

53
Q

Alcohols: most widely used disinfectants and antiseptics effective at a
concentration of 60–70% in water. They are _____ and ______ but not
sporicidal or virucidal

A

bactericidal
fungicidal

54
Q

Alcohols: most widely used disinfectants and antiseptics effective at a
concentration of 60–70% in water. They are bactericidal and fungicidal but not
____________.

A

sporicidal or virucidal

55
Q

are the two most
popular alcohol germicides. They act by denaturing bacterial proteins and
possibly by dissolving membrane lipids. They are used as skin antiseptics.
Methyl alcohol is effective against fungal spores

A

Ethyl alcohol and isopropyl alcohol

56
Q

________: are highly reactive molecules that combine with nucleic and
alkylating molecules; sporicidal and can be used as chemical sterilants. Example
is _______

A

Aldehydes
Formaldehyde

57
Q

: used for sterilization of large volume of heat-sensitive disposable
items and also instruments. Ethylene oxide, formaldehyde gas, and
betapropiolactone are frequently used gaseous agents.

A

Gases

58
Q

_____________: such as detergents are the substances that alter
energy relationship at interfaces producing a reduction in surface tension.
Detergents are organic molecules that serve as wetting agents and emulsifiers
because they have both polar hydrophilic and nonpolar hydrophobic ends thus
are very effective cleansing agents. They are different from soaps, which are
derived from fats.
Four types:

A

Surface active agents

(i) Cationic surface active agents ex: quaternary
ammonium compounds,
(ii) Anionic surface active agents, ex: soap made from
saturated or unsaturated fatty acids, (iii) Nonionic surface active agents (not
effective),
(iv) Amphoteric or ampholytic compounds or Tego compounds.

59
Q

: This group includes halogens, hydrogen peroxide,
potassium permanganate, and sodium perborate. They are good disinfectants
and antiseptics but are less effective in the presence of organic matter.

A

Oxidizing agents

60
Q

: used extensively as skin and wound antiseptics include (a) acridine
dyes and (b) aniline dyes both more active against Gram positive bacteria.

A

Dyes

61
Q

: Soluble salts of mercury, silver, copper, arsenic, and other
heavy metals have antibacterial activity, both bactericidal and bacteriostatic.
They combine with proteins, often with their sulfhydryl groups and inactivate
them or may also precipitate cell proteins.

A

Heavy metals

62
Q

(such as sulfuric acid, nitric acid, hydrochloric acid,
and benzoic acid)

A

Acids

63
Q

(like potassium and sodium hydroxide and
ammonium hydroxide) are germicidal in nature

A

alkalis

64
Q

They kill microorganisms by
hydrolysis and altering the pH of the medium.

A

Acids and alkalis

Microbiology (9 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions