Microbial Structure & Function 1 Flashcards
(182 cards)
1
Q
Does this describe eukaryotes or prokaryotes:
Cytoplasmic membrane contains sterols
A
Eukaryotes
2
Q
Morphology term for bacterial cells that are in chains
A
Strepto-
3
Q
Morphology term for bacterial cells that are in clusters
A
Staphylo-
4
Q
The only gram negative diplococci
A
Neisseria gonorrhea
5
Q
Mass of bacterial cells that arise from a single cell
A
Bacterial colony
6
Q
Bacterial energy production (electron transport) occurs here
A
Plasma membrane
7
Q
Two carbohydrate subunits that form the glycan chain of peptidoglycan
A
N-acetylglucosamine (NAG) and N-acetylmuramic acid (NAM)
8
Q
Consists of alternating series of two carbohydrate subunits forming the glycan chain (N-acetylglucosamine (NAG) and N-acetylmuramic acid (NAM))
A
Peptidoglycan
9
Q
Peptide portion of peptidoglycan always contains this in the third to last position
A
Di-amino acid
(either lysine or diaminopimelic acid)
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
11
Q
Peptide portion of peptidoglycan almost always ends in this
A
D-ala-D-ala
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
13
Q
This amino acid is deleted during cross linking of peptidoglycan
A
Terminal D-ala
14
Q
Rigid structure that surrounds the cytoplasmic membrane and determines the shape of the cell
Counters osmotic pressure
A
Bacterial cell wall
15
Q
Bacterial component that counters osmotic pressure
A
Cell wall
16
Q
Bacterial cell wall rigidity is due to this
A
Peptidoglycan
17
Q
Peptidoglycan provides this to the bacterial cell wall
A
Rigidity
18
Q
Does this describe gram negative or positive bacteria:
Has an outer membrane
A
Gram negative
19
Q
Does this describe gram negative or positive bacteria:
Has a thick peptidoglycan layer
A
Gram positive
20
Q
Does this describe gram negative or positive bacteria:
Does NOT have an outer membrane
A
Gram positive
21
Q
Does this describe gram negative or positive bacteria:
Has a thin peptidoglycan layer
A
Gram negative
22
Q
Does this describe gram negative or positive bacteria:
Contain LPS
A
Gram negative
23
Q
Does this describe gram negative or positive bacteria:
LPS absent
A
Gram positive
24
Q
Does this describe gram negative or positive bacteria:
Teichoic acid often present
A
Gram positive
25
Does this describe gram negative or positive bacteria:
Teichoic acid absent
Gram negative
26
Does this describe gram negative or positive bacteria:
Endotoxin absent
Gram positive
27
Does this describe gram negative or positive bacteria:
Endotoxin present
Gram negative
28
Does this describe gram negative or positive bacteria:
Sporulation by some bacteria
Gram positive
29
Does this describe gram negative or positive bacteria:
No sporulation
Gram negative
30
Does this describe gram negative or positive bacteria:
Sensitive to lysozyme
Gram positive
31
Does this describe gram negative or positive bacteria:
Resistant to lysozyme
Gram negative
32
Does this describe gram negative or positive bacteria:
More susceptible to penicillin
Gram positive
33
Does this describe gram negative or positive bacteria:
More resistant to penicillin
Gram negative
34
Is peptidoglycan permeable?
Yes, to numerous substances (e.g. antibiotics)
35
Does this describe gram negative or positive bacteria:
Higher osmotic pressure
Gram positive
36
Does this describe gram negative or positive bacteria:
Lower osmotic pressure
Gram negative
37
Part of gram positive bacteria that gives negative charge, attracts positive charges adding strength to the wall
Wall- and lipo-teichoic acid
38
Part of gram positive bacteria that are major antigens and may trigger fever
Wall- and lipo-teichoic acid
39
Molecules in gram negative bacteria that allow diffusion of small molecule solutes (ions and some nutrients)
Porins
40
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
Lipid A
41
Lipid A is this
Part of the LPS in gram negative bacteria that is an endotoxin
42
Portion of LPS that is a major antigenic determinant and is frequently used to characterize bacteria
O antigen
43
O antigen is this
Portion of LPS that is a major antigenic determinant
44
Two components of LPS in gram negative bacteria
Lipid A (endotoxin) and O antigen
45
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
Periplasm
46
Major permeability barrier in gram negative bacteria
Outer membrane
47
Why do many antibiotics work on gram positive but not gram negative bacteria?
Because they can't cross the outer membrane
48
Periplasm separates these
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
49
Periplasm contains this
Peptidoglycan and proteins that process solutes in transit between the outside and inside of the cell
50
4 steps of the gram stain
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)
51
Steps of gram stain where all bacteria are purple
1st (crystal violet) and 2nd (gram iodine) steps
52
Common counterstain used in gram stain
Safranin red
Stains gram negative cells red
53
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)
Mycobacteria
54
Mycobacterial cell wall consists of these 3 things
Thick peptidoglycan layer (like gram positives)
Arabinogalactan (sugar) layer
High concentration of mycolic acids (complicated long chain hydrophobic layer also called Wax D)
55
Mycobacterial cell wall is essentially a gram ______ cell wall with a ___________
Essentially a gram positive cell wall with an outer membrane
56
Mycobacterial cells stain poorly by the gram stain despite their thick peptidoglycan layer due to this
Stains have difficulty penetrating the waxy outer layer
57
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
Acid Fast stain
58
Primary stain in acid fast staining
Carbol Fuchsin
Stains the cells red
59
Acid fast stain is used to stain this type of bacteria
Mycobacteria
60
Mycobacteria are stained with this
Acid fast stain
61
Counterstain in an acid fast stain
Methylene blue
62
What color are mycobacterial cells in an acid fast stain?
Red
63
What color are non-mycobacterial cells in an acid fast stain?
Blue
64
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
Mycoplasma
65
Compounds in the mycoplasma membrane that provide strength
Sterols
66
Do mycoplasma have a cell wall?
No
67
Antigenic portion of flagella
H antigen
68
Motility through sensing chemicals
Chemotaxis
69
Rotation that is responsible for the run and tumble movement of bacteria
Flagella
70
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
Flagella
71
Chemical compound involved in chemotaxis that is a nutrient
Attractant
72
Chemical compound involved in chemotaxis that is toxic
Repellant
73
What helps H. pylori penetrate through the mucous coat?
Flagella
74
Are pili present in gram negative or positive bacteria?
Both
75
Pili responsible for attachment
Fimbriae
76
Type of motility that pili provide
Twitching motility
77
Type of pili that are hollow
Conjugation pili
78
3 main functions of pili
Attachment (fimbriae)
Movement
Conjugation
79
Distinct gelatinous layer
Capsule
80
Irregular diffuse layer
Slime layer
81
Most capsules and slime layers are made of this
Polysaccharide
82
The capsules and slime layers are also referred to as this
Glycocalyx
(sugar shell)
83
2 general functions of capsules and slime layers
Protection from host defenses (innate immunity)
Antigenic and eventually provoke an antibody response
84
non-replicating resting cells that are highly resistant to numerous environmental stresses (including boiling, radiation, chemicals, and drying)
Endospores
85
Ineffective canning can lead to this
Botulism
(due to endospores)
86
2 bacteria whose endospores are persistent in soil
Anthrax and tetanus
87
These are the end result of a developmental program that replaces a vegetative (growing) cell with a spore
Endospores
88
Process by which spores return to the vegetative state when conditions improve
Germination
89
Are endospores reproductive or replicating?
No neither
90
Bacterial growth curve:
Phase that is a period of adjustment to new medium requiring enzyme synthesis and gearing up for growth
Lag phase
91
Bacterial growth curve:
Phase where exponentially increasing cell numbers can lead to rapid accumulation of cells
Logarithmic/exponential phase
92
Time it takes for one division cycle
The inverse is growth rate (generations/hour)
Generation time (time/generation)
93
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
Stationary phase
94
Phase of bacterial growth curve when endospores are formed
Stationary phase
95
Bacterial growth curve:
Phase where cells begin dying off due to toxic byproducts
Death phase
96
Bacterial cells probably do not grow in this form like they grow in a test tube, except for in the colon
Planktonic form
97
Complex structures with regions of metabolically differently acting cells that are not well duplicated in a culture tube
Biofilms
98
Cells in a stable biofilm are similar to cells in this phase of the bacterial growth curve
Stationary phase
99
Are cells in a biofilm more or less tolerant to antibiotics and immune attack than planktonic cells?
More tolerant
Allows persistent cells to remain after treatment or immune response
100
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
Extracellular polymeric substances (EPS)
101
Resistance or persistence:
stable genetic change that is passed down to cell progeny
Resistance
102
Resistance or persistence:
metabolic state that allows transient tolerance to antibiotics and other stress, but is not passed down to cell progeny
Persistence
103
Standard antibiotic sensitivity testing does not identify _____ bacteria
Persistent
104
Two aspects of metabolism that affect how well bacteria deal with oxygen
Whether the bacterium is able to perform respiration, fermentation, or both
Whether the bacterium is able to efficiently detoxify oxygen
105
Reduction of oxygen during respiration leads to the formation of these two compounds that are highly toxic to bacteria
Superoxide anion (O2-) and Hydrogen peroxide (H2O2)
106
Relatively simple test that will distinguish the gram positive cocci Staphylococcus (test +) and Streptococcus (test -)
Catalase test
107
Catalase test distinguishes between these two bacteria
Gram positive cocci Staphylococcus (catalase +) and Streptococcus (catalase -)
108
Gram positive cocci that is catalase positive
Staphylococcus
109
Gram positive cocci that is catalase negative
Streptococcus
110
Is staphylococcus catalase positive or negative?
Positive
111
Is streptococcus catalase positive or negative?
Negative
112
Type of bacteria that grows only when O2 is available
Obligate aerobe
113
Type of bacteria that grows best when O2 is available, but also grows without it
Facilitative anaerobe
114
floating biofilm formed at the air–liquid interface in static culture conditions
Pellicle
115
Type of bacteria that cannot grow when O2 is present
Obligate anaerobe
116
Type of bacteria that grows only if small amounts of O2 are available
Microaerophile
117
Type of bacteria that grows equally well with or without O2
Aerotolerant anaerobe
118
extremophilic organisms that are capable of growth and reproduction in low temperatures, ranging from −20 °C to 20 °C
Psychrophiles
119
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
Psychrotroph
120
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
Mesophile
121
organism—a type of extremophile—that thrives at relatively high temperatures, between 41 and 122 °C
Thermophile
122
organism that thrives in extremely hot environments—from 60 °C upwards. An optimal temperature for their existence is often above 80 °C
Hyperthermophile
123
disinfectant nontoxic enough to be used on skin
Antiseptic
124
procedures that help prevent the accidental introduction of unwanted microbes
Antiseptic technique
125
substance that kills bacteria
Bactericide
126
compound that prevents the growth of bacteria, but does not kill them
Bacteriostatic
127
brief heat treatment that reduces the number of spoilage organisms and destroys disease-causing microbes
Pasteurization
128
inhibition of microbial growth to delay spoilage
Preservation
129
free of all viable microbes, including endospores and viruses
Sterile
130
the destruction or removal of all microbes through physical or chemical means
Sterilization
131
a chemical that destroys many, but not all, microbes
Disinfectant
132
Does sterilization or disinfection destroy all microbes?
Sterilization
133
Does sterilization or disinfection destroy many but not all microbes?
Disinfection
134
Most useful treatment for microbial control
Heat
135
3 methods of moist heat
Boiling (disinfection)
Pasteurization (disinfection)
Pressurized steam (sterilization)
136
Moist heat method:
Disinfection
Destroys most microorganisms and viruses
Does not sterilize
Destroys vegetative cells but not endospores
Boiling
137
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
Pasteurization
138
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
Pressurized steam
139
Disinfection or sterilization:
Boiling
Disinfection
140
Disinfection or sterilization:
Pasteurization
Disinfection
141
Disinfection or sterilization:
Pressurized steam
Sterilization
uses autoclave
142
Disinfection or sterilization:
Dry heat; charring
Sterilization
143
What is more effective, moist or dry heat?
Moist
144
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
Dry heat / charring
145
How effective is cold as control?
Does not kill most bacteria; stops or slows growth
Kills some cells in a population but not all
Endospores are also resistant
146
Process that removes water from a material through a controlled freezing and vacuum application
Used for long term storage of bacteria
Lyophilization
147
Technique used for heat sensitive fluids that need to retain biological activity
Liquid filtration
148
Pore size required in membrane filtration for Mycoplasma
0.22 um
149
Does filtration remove viruses?
NO
150
Filtration of air uses these
High efficiency particulate air (HEPA) filters
151
Pores used in membrane filters are generally this size
0.22-0.45 um
152
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)
Ionizing radiation (gamma rays)
153
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
Ultraviolet radiation
154
Does ionizing radiation penetrate plastic?
Yes, so can sterilize plastic petri dishes, syringes, etc.
155
Does ultraviolet radiation penetrate glass?
No
156
Does ultraviolet radiation penetrate water?
No
157
Does high pressure processing use high temperatures?
No; employs high pressures up to 130,000 psi
Destroys microbes by denaturing proteins and altering cell membrane permeability
158
chemicals used to disinfect or sterilize
Germicidal chemicals
159
Is 100% alcohol effective in controlling bacteria?
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
Is alcohol effective against endospores and viruses?
Not effective against endospores and some naked viruses
161
Mode of action of alcohol as a germicide
Coagulation of proteins and essential enzymes
Damage to lipid membranes
162
Alcohol as a germicide kills these types of microbes
Vegetative bacteria and fungi
(Not effective against endospores and some naked viruses)
163
Solution made from formaldehyde used to disinfect surfaces; kills bacteria and inactivates viruses
Formalin
164
Hand sanitizer commonly uses this germicide
Alcohol
165
Surface disinfectant commonly uses this type of germicide
Alkylating agents (e.g. formalin)
166
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
Alkylating agents
167
3 types of oxidizing agents used as germicides
Halogens and hydrogen peroxide
Chlorine
Iodine
168
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
Halogens and hydrogen peroxide
169
Type of oxidizing agent:
Destroys all types of organisms and viruses
Used as a disinfectant (caustic to skin)
Chlorine (e.g. bleach)
170
Type of oxidizing agent:
Kills vegetative cells, not reliable with endospores
Used in tincture or on skin
Iodine (e.g. betadine)
171
What type of microbes does halogens and hydrogen peroxide (oxidizing agent) kill?
Bactericidal
172
What type of microbes does bleach (oxidizing agent) kill?
All types of organisms and viruses
173
What type of microbes does iodine (oxidizing agent) kill?
Kills vegetative cells, not reliable with endospores
174
Difference between halogens and hydrogen peroxide (oxidizing agents) and heavy metal compounds?
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
Creams containing this metal are used to prevent secondary infections
Silver sulfadiazine
176
Metal used in eye drops of newborns to prevent gonococcal infection
Silver nitrate
177
Germicide that reacts with sulfhydryl groups forming ionic bonds which interfere with protein function
Action is reversible therefore bacteriostatic
Heavy metal compounds
178
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
Phenolics (carbolic acid)
179
Phenolic that is used in soaps and lotions
Halogenated diphenyls
180
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
Quaternary ammonium compounds (Quats)
Cationic detergent
181
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
Anionic detergents (soaps)
182
Are anionic detergents more effective on gram positive or negative bacteria?
More effective on Gram negatives since they insert into the lipid rich outer membrane
