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MF2 Final study > Microbial structure and function > Flashcards

Microbial structure and function Flashcards

1
Q

Does this describe eukaryotes or prokaryotes:
Cytoplasmic membrane contains sterols

A

Eukaryotes

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2
Q

Morphology term for bacterial cells that are in chains

A

Strepto-

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3
Q

Morphology term for bacterial cells that are in clusters

A

Staphylo-

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4
Q

The only gram negative diplococci

A

Neisseria gonorrhea

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5
Q

Mass of bacterial cells that arise from a single cell

A

Bacterial colony

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6
Q

Bacterial energy production (electron transport) occurs here

A

Plasma membrane

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7
Q

Two carbohydrate subunits that form the glycan chain of peptidoglycan

A

N-acetylglucosamine (NAG) and N-acetylmuramic acid (NAM)

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8
Q

Consists of alternating series of two carbohydrate subunits forming the glycan chain (N-acetylglucosamine (NAG) and N-acetylmuramic acid (NAM))

A

Peptidoglycan

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9
Q

Peptide portion of peptidoglycan always contains this in the third to last position

A

Di-amino acid
(either lysine or diaminopimelic acid)

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10
Q

Peptidoglycan always contain a di-amino acid (lysine or diaminopimelic acid) in this position

A

Third to last position of the peptide portion

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11
Q

Peptide portion of peptidoglycan almost always ends in this

A

D-ala-D-ala

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12
Q

Peptidoglycan cross-linking occurs by joining these

A

Penultimate D-ala of one peptide chain to the diamino acid of the other with deletion of the terminal D-ala

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13
Q

This amino acid is deleted during cross linking of peptidoglycan

A

Terminal D-ala

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14
Q

Rigid structure that surrounds the cytoplasmic membrane and determines the shape of the cell
Counters osmotic pressure

A

Bacterial cell wall

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15
Q

Bacterial component that counters osmotic pressure

A

Cell wall

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16
Q

Bacterial cell wall rigidity is due to this

A

Peptidoglycan

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17
Q

Peptidoglycan provides this to the bacterial cell wall

A

Rigidity

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18
Q

Does this describe gram negative or positive bacteria:
Has an outer membrane

A

Gram negative

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19
Q

Does this describe gram negative or positive bacteria:
Has a thick peptidoglycan layer

A

Gram positive

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20
Q

Does this describe gram negative or positive bacteria:
Does NOT have an outer membrane

A

Gram positive

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21
Q

Does this describe gram negative or positive bacteria:
Has a thin peptidoglycan layer

A

Gram negative

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22
Q

Does this describe gram negative or positive bacteria:
Contain LPS

A

Gram negative

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23
Q

Does this describe gram negative or positive bacteria:
LPS absent

A

Gram positive

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24
Q

Does this describe gram negative or positive bacteria:
Teichoic acid often present

A

Gram positive

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25
Q

Does this describe gram negative or positive bacteria:
Teichoic acid absent

A

Gram negative

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26
Q

Does this describe gram negative or positive bacteria:
Endotoxin absent

A

Gram positive

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27
Q

Does this describe gram negative or positive bacteria:
Endotoxin present

A

Gram negative

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28
Q

Does this describe gram negative or positive bacteria:
Sporulation by some bacteria

A

Gram positive

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29
Q

Does this describe gram negative or positive bacteria:
No sporulation

A

Gram negative

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30
Q

Does this describe gram negative or positive bacteria:
Sensitive to lysozyme

A

Gram positive

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31
Q

Does this describe gram negative or positive bacteria:
Resistant to lysozyme

A

Gram negative

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32
Q

Does this describe gram negative or positive bacteria:
More susceptible to penicillin

A

Gram positive

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33
Q

Does this describe gram negative or positive bacteria:
More resistant to penicillin

A

Gram negative

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34
Q

Is peptidoglycan permeable?

A

Yes, to numerous substances (e.g. antibiotics)

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35
Q

Does this describe gram negative or positive bacteria:
Higher osmotic pressure

A

Gram positive

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36
Q

Does this describe gram negative or positive bacteria:
Lower osmotic pressure

A

Gram negative

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37
Q

Part of gram positive bacteria that gives negative charge, attracts positive charges adding strength to the wall

A

Wall- and lipo-teichoic acid

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38
Q

Part of gram positive bacteria that are major antigens and may trigger fever

A

Wall- and lipo-teichoic acid

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39
Q

Molecules in gram negative bacteria that allow diffusion of small molecule solutes (ions and some nutrients)

A

Porins

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40
Q

Part of lipopolysaccharide in gram negative bacteria that is an endotoxin
Release of small amounts in the blood can lead to fever, shock, and death during infections with gram negative bacteria

A

Lipid A

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41
Q

Lipid A is this

A

Part of the LPS in gram negative bacteria that is an endotoxin

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42
Q

Portion of LPS that is a major antigenic determinant and is frequently used to characterize bacteria

A

O antigen

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43
Q

O antigen is this

A

Portion of LPS that is a major antigenic determinant

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44
Q

Two components of LPS in gram negative bacteria

A

Lipid A (endotoxin) and O antigen

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45
Q

Part of gram negative bacteria that separates the inner and outer membranes and contains the peptidoglycan and proteins which process solutes in transit between the outside and inside of the cell

A

Periplasm

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46
Q

Major permeability barrier in gram negative bacteria

A

Outer membrane

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47
Q

Why do many antibiotics work on gram positive but not gram negative bacteria?

A

Because they can’t cross the outer membrane

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48
Q

Periplasm separates these

A

Inner and outer membranes of gram negative bacteria
Contains peptidoglycan and protein which process solutes in transit between the outside and inside of the cell

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49
Q

Periplasm contains this

A

Peptidoglycan and proteins that process solutes in transit between the outside and inside of the cell

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50
Q

4 steps of the gram stain

A
  1. Crystal violet (stains all purple)
  2. Gram iodine (fixes the dye)
  3. Decolorizer with alcohol or aceton (removes color from gram negative, gram positive remain purple)
  4. Counterstain with safranin red (gram - are still purple, gram + not red)
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51
Q

Steps of gram stain where all bacteria are purple

A

1st (crystal violet) and 2nd (gram iodine) steps

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52
Q

Common counterstain used in gram stain

A

Safranin red
Stains gram negative cells red

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53
Q

Type of bacteria that has a cell wall that is essentially gram positive with an outer membrane
Consists of thick peptidoglycan layer, arabinogalactan layer, high concentartion of mycolic acids (layer called Wax D)

A

Mycobacteria

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54
Q

Mycobacterial cell wall consists of these 3 things

A

Thick peptidoglycan layer (like gram positives)
Arabinogalactan (sugar) layer
High concentration of mycolic acids (complicated long chain hydrophobic layer also called Wax D)

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55
Q

Mycobacterial cell wall is essentially a gram ______ cell wall with a ___________

A

Essentially a gram positive cell wall with an outer membrane

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56
Q

Mycobacterial cells stain poorly by the gram stain despite their thick peptidoglycan layer due to this

A

Stains have difficulty penetrating the waxy outer layer

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57
Q

Type of stain:
Carbol Fuchsin primary stain steamed in to penetrate the membrane, stains the cells red
Acid alcohol leaches the stain out of all cells that are not mycobacteria
Methylene blue counterstains leached cells

A

Acid Fast stain

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58
Q

Primary stain in acid fast staining

A

Carbol Fuchsin
Stains the cells red

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59
Q

Acid fast stain is used to stain this type of bacteria

A

Mycobacteria

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60
Q

Mycobacteria are stained with this

A

Acid fast stain

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61
Q

Counterstain in an acid fast stain

A

Methylene blue

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62
Q

What color are mycobacterial cells in an acid fast stain?

A

Red

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63
Q

What color are non-mycobacterial cells in an acid fast stain?

A

Blue

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64
Q

Type of bacteria without a cell wall
Causes a variety of diseases including a generally mild pneumonia
Sterols in the membrane account for its strength

A

Mycoplasma

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65
Q

Compounds in the mycoplasma membrane that provide strength

A

Sterols

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66
Q

Do mycoplasma have a cell wall?

A

No

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67
Q

Antigenic portion of flagella

A

H antigen

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68
Q

Motility through sensing chemicals

A

Chemotaxis

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69
Q

Rotation that is responsible for the run and tumble movement of bacteria

A

Flagella

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70
Q

Bacterial component that:
Use propeller like movement for motility
Antigenic
Rotation is reversible, can be clockwise or counterclockwise
Chemotaxis
Responsible for run and tumble movement

A

Flagella

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71
Q

Chemical compound involved in chemotaxis that is a nutrient

A

Attractant

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72
Q

Chemical compound involved in chemotaxis that is toxic

A

Repellant

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73
Q

What helps H. pylori penetrate through the mucous coat?

A

Flagella

74
Q

Are pili present in gram negative or positive bacteria?

A

Both

75
Q

Pili responsible for attachment

A

Fimbriae

76
Q

Type of motility that pili provide

A

Twitching motility

77
Q

Type of pili that are hollow

A

Conjugation pili

78
Q

3 main functions of pili

A

Attachment (fimbriae)
Movement
Conjugation

79
Q

Distinct gelatinous layer

A

Capsule

80
Q

Irregular diffuse layer

A

Slime layer

81
Q

Most capsules and slime layers are made of this

A

Polysaccharide

82
Q

The capsules and slime layers are also referred to as this

A

Glycocalyx
(sugar shell)

83
Q

2 general functions of capsules and slime layers

A

Protection from host defenses (innate immunity)
Antigenic and eventually provoke an antibody response

84
Q

non-replicating resting cells that are highly resistant to numerous environmental stresses (including boiling, radiation, chemicals, and drying)

A

Endospores

85
Q

Ineffective canning can lead to this

A

Botulism
(due to endospores)

86
Q

2 bacteria whose endospores are persistent in soil

A

Anthrax and tetanus

87
Q

These are the end result of a developmental program that replaces a vegetative (growing) cell with a spore

A

Endospores

88
Q

Process by which spores return to the vegetative state when conditions improve

A

Germination

89
Q

Are endospores reproductive or replicating?

A

No neither

90
Q

Bacterial growth curve:
Phase that is a period of adjustment to new medium requiring enzyme synthesis and gearing up for growth

A

Lag phase

91
Q

Bacterial growth curve:
Phase where exponentially increasing cell numbers can lead to rapid accumulation of cells

A

Logarithmic/exponential phase

92
Q

Time it takes for one division cycle
The inverse is growth rate (generations/hour)

A

Generation time (time/generation)

93
Q

Bacterial growth curve:
Phase where nutrients become limiting, toxic by-products begin to accumulate
Cells change their genetic program and enter a dormant phase, make endospores if they can

A

Stationary phase

94
Q

Phase of bacterial growth curve when endospores are formed

A

Stationary phase

95
Q

Bacterial growth curve:
Phase where cells begin dying off due to toxic byproducts

A

Death phase

96
Q

Bacterial cells probably do not grow in this form like they grow in a test tube, except for in the colon

A

Planktonic form

97
Q

Complex structures with regions of metabolically differently acting cells that are not well duplicated in a culture tube

A

Biofilms

98
Q

Cells in a stable biofilm are similar to cells in this phase of the bacterial growth curve

A

Stationary phase

99
Q

Are cells in a biofilm more or less tolerant to antibiotics and immune attack than planktonic cells?

A

More tolerant
Allows persistent cells to remain after treatment or immune response

100
Q

During biofilm formation, bacteria multiply and produce this
Other bacteria may attach to this, and eventually channels are created in it that allow nutrients and waste products to pass

A

Extracellular polymeric substances (EPS)

101
Q

Resistance or persistence:
stable genetic change that is passed down to cell progeny

A

Resistance

102
Q

Resistance or persistence:
metabolic state that allows transient tolerance to antibiotics and other stress, but is not passed down to cell progeny

A

Persistence

103
Q

Standard antibiotic sensitivity testing does not identify _____ bacteria

A

Persistent

104
Q

Two aspects of metabolism that affect how well bacteria deal with oxygen

A

Whether the bacterium is able to perform respiration, fermentation, or both
Whether the bacterium is able to efficiently detoxify oxygen

105
Q

Reduction of oxygen during respiration leads to the formation of these two compounds that are highly toxic to bacteria

A

Superoxide anion (O2-) and Hydrogen peroxide (H2O2)

106
Q

Relatively simple test that will distinguish the gram positive cocci Staphylococcus (test +) and Streptococcus (test -)

A

Catalase test

107
Q

Catalase test distinguishes between these two bacteria

A

Gram positive cocci Staphylococcus (catalase +) and Streptococcus (catalase -)

108
Q

Gram positive cocci that is catalase positive

A

Staphylococcus

109
Q

Gram positive cocci that is catalase negative

A

Streptococcus

110
Q

Is staphylococcus catalase positive or negative?

A

Positive

111
Q

Is streptococcus catalase positive or negative?

A

Negative

112
Q

Type of bacteria that grows only when O2 is available

A

Obligate aerobe

113
Q

Type of bacteria that grows best when O2 is available, but also grows without it

A

Facilitative anaerobe

114
Q

floating biofilm formed at the air–liquid interface in static culture conditions

A

Pellicle

115
Q

Type of bacteria that cannot grow when O2 is present

A

Obligate anaerobe

116
Q

Type of bacteria that grows only if small amounts of O2 are available

A

Microaerophile

117
Q

Type of bacteria that grows equally well with or without O2

A

Aerotolerant anaerobe

118
Q

extremophilic organisms that are capable of growth and reproduction in low temperatures, ranging from −20 °C to 20 °C

A

Psychrophiles

119
Q

cold-tolerant bacteria or archaea that have the ability to grow at low temperatures but have optimal and maximal growth temperatures above 15 and 20°C, respectively

A

Psychrotroph

120
Q

organism that grows best in moderate temperature, neither too hot nor too cold, with an optimum growth range from 20 to 45 °C. The optimum growth temperature for these organisms is 37 °C

A

Mesophile

121
Q

organism—a type of extremophile—that thrives at relatively high temperatures, between 41 and 122 °C

A

Thermophile

122
Q

organism that thrives in extremely hot environments—from 60 °C upwards. An optimal temperature for their existence is often above 80 °C

A

Hyperthermophile

123
Q

disinfectant nontoxic enough to be used on skin

A

Antiseptic

124
Q

procedures that help prevent the accidental introduction of unwanted microbes

A

Antiseptic technique

125
Q

substance that kills bacteria

A

Bactericide

126
Q

compound that prevents the growth of bacteria, but does not kill them

A

Bacteriostatic

127
Q

brief heat treatment that reduces the number of spoilage organisms and destroys disease-causing microbes

A

Pasteurization

128
Q

inhibition of microbial growth to delay spoilage

A

Preservation

129
Q

free of all viable microbes, including endospores and viruses

A

Sterile

130
Q

the destruction or removal of all microbes through physical or chemical means

A

Sterilization

131
Q

a chemical that destroys many, but not all, microbes

A

Disinfectant

132
Q

Does sterilization or disinfection destroy all microbes?

A

Sterilization

133
Q

Does sterilization or disinfection destroy many but not all microbes?

A

Disinfection

134
Q

Most useful treatment for microbial control

A

Heat

135
Q

3 methods of moist heat

A

Boiling (disinfection)
Pasteurization (disinfection)
Pressurized steam (sterilization)

136
Q

Moist heat method:
Disinfection
Destroys most microorganisms and viruses
Does not sterilize
Destroys vegetative cells but not endospores

A

Boiling

137
Q

Moist heat method:
Disinfection
Used for killing specific pathogens spread in food and beverages like milk, cheese, wine, or fruit juices that would be ruined by autoclaving
Variety of protocols varying in temperature and time of exposure
All designed to kill target organisms but lower temps/times may spare beneficial organisms and enzymes

A

Pasteurization

138
Q

Moist heat method:
Sterilization
Autoclave achieves sterilization at 121 degrees C and 15 psi in 20 minutes
Cannot be used for:
Solutions containing temperature sensitive biochemicals like antibiotics, enzymes
Meltable plastics like petri dishes
Some rustable metals

A

Pressurized steam

139
Q

Disinfection or sterilization:
Boiling

A

Disinfection

140
Q

Disinfection or sterilization:
Pasteurization

A

Disinfection

141
Q

Disinfection or sterilization:
Pressurized steam

A

Sterilization
uses autoclave

142
Q

Disinfection or sterilization:
Dry heat; charring

A

Sterilization

143
Q

What is more effective, moist or dry heat?

A

Moist

144
Q

Type of heat method:
Sterilization requires longer times and higher temperatures
Kills cells and endospores
Good for steel that might rust from the moisture in the autoclave or powders that would be ruined by the moisture
Incineration method

A

Dry heat / charring

145
Q

How effective is cold as control?

A

Does not kill most bacteria; stops or slows growth
Kills some cells in a population but not all
Endospores are also resistant

146
Q

Process that removes water from a material through a controlled freezing and vacuum application
Used for long term storage of bacteria

A

Lyophilization

147
Q

Technique used for heat sensitive fluids that need to retain biological activity

A

Liquid filtration

148
Q

Pore size required in membrane filtration for Mycoplasma

A

0.22 um

149
Q

Does filtration remove viruses?

A

NO

150
Q

Filtration of air uses these

A

High efficiency particulate air (HEPA) filters

151
Q

Pores used in membrane filters are generally this size

A

0.22-0.45 um

152
Q

Radiation type:
Water in the cell is ionized creating oxidizing and reducing radicals that destroy DNA
High initial cost but very efficient and effective
Good for sterilizing things that would melt or otherwise be destroyed by heat (e.g. plastic Petri dishes, syringes, catheters, vaccines, etc.)
Penetrates plastic so can sterilize (e.g. Petri plates in bags)

A

Ionizing radiation (gamma rays)

153
Q

Radiation type:
DNA absorbs UV light (260 nm) and forms thymine dimers at adjacent thymines that inhibits replication and leads to cell death
Does not penetrate glass, water or even paper
Useful as lights in ORs and laboratories that are turned on after everyone leaves to disinfect surfaces

A

Ultraviolet radiation

154
Q

Does ionizing radiation penetrate plastic?

A

Yes, so can sterilize plastic petri dishes, syringes, etc.

155
Q

Does ultraviolet radiation penetrate glass?

A

No

156
Q

Does ultraviolet radiation penetrate water?

A

No

157
Q

Does high pressure processing use high temperatures?

A

No; employs high pressures up to 130,000 psi
Destroys microbes by denaturing proteins and altering cell membrane permeability

158
Q

chemicals used to disinfect or sterilize

A

Germicidal chemicals

159
Q

Is 100% alcohol effective in controlling bacteria?

A

NO - pure alcohol only absorbs water from the cell and dehydrates it
Solutions of 60-80% isopropyl or ethyl alcohol kills vegetative bacteria and fungi

160
Q

Is alcohol effective against endospores and viruses?

A

Not effective against endospores and some naked viruses

161
Q

Mode of action of alcohol as a germicide

A

Coagulation of proteins and essential enzymes
Damage to lipid membranes

162
Q

Alcohol as a germicide kills these types of microbes

A

Vegetative bacteria and fungi
(Not effective against endospores and some naked viruses)

163
Q

Solution made from formaldehyde used to disinfect surfaces; kills bacteria and inactivates viruses

A

Formalin

164
Q

Hand sanitizer commonly uses this germicide

A

Alcohol

165
Q

Surface disinfectant commonly uses this type of germicide

A

Alkylating agents (e.g. formalin)

166
Q

Germicide that works by adding methyl or ethyl groups to reactive sites in proteins
Includes aldehydes (formaldehyde and glutaraldehyde) and ethylene oxide gas
Bactericidal
Destroy organisms by inactivating proteins and DNA

A

Alkylating agents

167
Q

3 types of oxidizing agents used as germicides

A

Halogens and hydrogen peroxide
Chlorine
Iodine

168
Q

Type of oxidizing agent:
Common disinfectants
React with active hydrogens or sulfhydryl groups
Similar in action to the heavy metals but oxidize these bonds to form an irreversible covalent bond between two sulfur atoms
Action is irreversible therefore bactericidal

A

Halogens and hydrogen peroxide

169
Q

Type of oxidizing agent:
Destroys all types of organisms and viruses
Used as a disinfectant (caustic to skin)

A

Chlorine (e.g. bleach)

170
Q

Type of oxidizing agent:
Kills vegetative cells, not reliable with endospores
Used in tincture or on skin

A

Iodine (e.g. betadine)

171
Q

What type of microbes does halogens and hydrogen peroxide (oxidizing agent) kill?

A

Bactericidal

172
Q

What type of microbes does bleach (oxidizing agent) kill?

A

All types of organisms and viruses

173
Q

What type of microbes does iodine (oxidizing agent) kill?

A

Kills vegetative cells, not reliable with endospores

174
Q

Difference between halogens and hydrogen peroxide (oxidizing agents) and heavy metal compounds?

A

Both react with sulfhydryl groups, but halogens oxidize the bonds to form an irreversible covalent bond (bactericidal), while metals form ionic bonds which interfere with protein function and are reversible (bacteriostatic)

175
Q

Creams containing this metal are used to prevent secondary infections

A

Silver sulfadiazine

176
Q

Metal used in eye drops of newborns to prevent gonococcal infection

A

Silver nitrate

177
Q

Germicide that reacts with sulfhydryl groups forming ionic bonds which interfere with protein function
Action is reversible therefore bacteriostatic

A

Heavy metal compounds

178
Q

Germicide that penetrates and destroys membranes, denatures and precipitates proteins
Kills most vegetative cells
Can kill mycobacterium at high concentrations
Not reliable on all groups of viruses

A

Phenolics (carbolic acid)

179
Q

Phenolic that is used in soaps and lotions

A

Halogenated diphenyls

180
Q

Nontoxic, used to disinfect food preparation surfaces
Reduces surface tension aiding in the removal of dirt and organic matter. They are attracted to the negatively charged cell by their positively charged amine
Also disrupts bacterial and viral membranes
Commonly used for wound irrigation and pre-op antiseptic

A

Quaternary ammonium compounds (Quats)
Cationic detergent

181
Q

Have negative charge
Mainly fatty acid derivatives
Hydrophobic end enters the membrane and disrupts it causing lysis
More effective on Gram negatives since they insert into the lipid rich outer membrane

A

Anionic detergents (soaps)

182
Q

Are anionic detergents more effective on gram positive or negative bacteria?

A

More effective on Gram negatives since they insert into the lipid rich outer membrane

MF2 Final study (28 decks)

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