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Flashcards in exam 1 Deck (179):
1

which of the below factors are likely to affect the efficacy of an antimicrobial agent?

-concentration of the agent
-ph
-microbial population density and heterogeneity
- duration of exposure to the antimicrobial agent

2

which of the biological domain includes viruses

none do

3

blue- green algae are properly assigned to which of the below domain

bacteria

4

which of the below does NOT include prokaryotic micooranism`

protozoa
fungi
red algae

5

Chemotherapeutic agents are ALWAYS, by definition

used to treat sick people, or animals

6

What is the best operational definition of auxotrophs?

A. Mutants that are deficient in biosynthetic capability relative to the wild type (prototrophs).

7

Continuous culture of bacteria

B. can be controlled by monitoring culture turbidity
C. is rate limited by the dilution rate of fresh media into the culture vessel
D. results in continuous maintenance of logarithmic growth kinetics

8

The adverse pharmacological effects of endotoxin are associated with which bacterial structure?

B. the outer membrane of gram-negative bacteria

9

Given a log phase bacterial culture with 106 cells per ml and a generation time of 30 minutes, how long does it take the culture to reach a density of 6.4  107 cells per ml?

C. 3 hours

10

Robert Koch who developed logical guidelines to establish microbial etiology of a disease also

A. established etiology of tuberculosis.
B. established etiology of anthrax.
C. developed a better solidifying agent for solid microbiological media.
D. used Petri dishes.

11

The most probable number methodologies

A. count viable bacteria.
B. are based on a statistical probability of inoculating a “tube” of medium with a viable bacterium or group of bacteria.
C. requires an incubation period

12

Extreme thermophiles, methanogens, and extreme halophiles are most likely affiliated with which of the below taxa

archaea

13

Quorum sensing mechanisms allow microorganisms

B. to express certain genetic capabilities (e.g., bioluminescence) only when the population density is high enough to have an effect on their survival

14

Treponema pallidum is best described as having which morphology

B. flexible spiral

15

Which group(s) of microbial entities is/are always obligate intracellular parasites, i.e., they must replicate inside cells.

E. Viruses

16

Periplasmic space

D. between cytoplasmic membrane and outer membrane of prokaryotes

17

Lysozyme AND Penicillin are active against which of the below?

bacteria

18

What are potential limitations of applying Koch’s Postulates?

A. Ethics of inoculating animals or humans with pathogens
B. Inability to grow some organisms on artificial medium
C. Inability to isolate microbial pathogen in pure culture
D. Inability to maintain virulence of a pathogen outside of the animal or plant host

19

A filter capable of removing essentially all bacteria from a liquid will have approximately what pore size?

C. 0.2 µm

20

The concept that human and animal diseases are caused by microorganisms is called the

B. germ theory

21

Which is NOT true concerning prokaryotic plasmids?

E. They may be composed of RNA.

22

Who first used carbolic acid as a disinfectant?

A. Joseph Lister

23

A culture of Escherichia coli is growing on a medium containing beef extract as C and N sources. What best describes its mode of growth?

C. chemoorganotrophy

24

The physical parameter killing bacteria in an autoclave is

heat

25

The study of bioinformatics and the analysis of genomic information of microorganism is most efficiently conducted

in silico

26

The carbon source for heterotrophic microorganisms is

C. always organic

27

Which is a gas used in microbial control?

B. methyl bromide

28

Which transport mechanism(s) are subject to rate limitations due to substrate saturation of a carrier protein?

B. facilitated diffusion
C. active transport
D. ABC, PEP-mediated group translocation, membrane-potential mediated transport
E. Protein-mediated transport of sugars

29

If one applies dry heat to sterilize disposable plastic pipettes

A. a temperature higher than that of an autoclave will be required.
B. there will be no living organisms on the pipettes.
C. there will be no pathogenic organisms on the pipettes, and even heat-resistant spores will be killed.
D. the pipettes will melt from the heat required.

30

The minimal effective concentration of a new Disinfectant X kills a standard suspension of Staphylococcus aureus at a dilution of 1:100; phenol produces the same killing effect at a dilution of 1:10. What is the phenol coefficient of the new Disinfectant X

10

31

The minimal effective concentration of Disinfectant Y kills a standard suspension of Staphylococcus aureus at a dilution of 1/1000; phenol produces the same killing effect at a dilution of 1/25. What is the phenol coefficient of phenol?

1

32

Compounds secreted outside microbial cells with an extremely high affinity for binding ferrous iron (Fe2+) are called

E. do not exist

33

Approximately, what is the percentage of Domain Bacteria are estimated to be culturable in the laboratory?

E. 0.1%

34

Who of the following developed criteria to establish microbial etiology of a particular disease?

E. Koch

35

The MIT (Madonna-Inspired Technology) is a type of control of microbes that

A. depends on air filtration.
B. maintains sterility.
C. will work at room temperature.

36

When Vibrio fischeri colonizes the surface of a small squid, it “decides” whether or not to turn on bioluminescence by using a regulatory mechanism termed

A. quorum sensing

37

Surfactants

A. may be microbicidal.
B. disrupt lipid membranes.
C. reduce interfacial tension between hydrophobic and hydrophilic materials (e.g., oil and water) and lower the surface tension of water.
D. may be synthesized by microorganisms to allow easier biodegradation of hydrophobic materials or even as self protection against predators.

38

If you pass an inoculation loop through a flame to heat it to incandescence, it becomes

A. sterile
B. sanitary
C. disinfected
D. hot

39

Which would be the method of choice for sterilization of heavy bedding (blankets, mattresses)?

B. ethylene oxide

40

Biological amino acids are typically L-amino acids; which prokaryotic cell component contains D-amino acids?

A. murein

41

Who of the following is often referred as the “Father of Microbiology?”

B. Louis Pasteur

42

Which is/are methods effecting sterilization?

A. incineration
B. autoclaving
C. ethylene oxide
D. gamma ray irradiation

43

Which culture regime can maintain log-phase cells indefinitely?

A. continuous culture

44

Turbidostatic or chemostatic culture control has reference to which of the below??

A. continuous culture

45

The term describing the condition in which microorganisms survive and grow under very low nutrient concentrations is

B. psychrotroph.

46

After one applies a chemical to sanitize a working surface in a food preparation area

B. the surface may be sterile.
C. the surface may not be sterile.
D. the surface may meet public health standards.

47

Which element below might be a catalytic-level or a micronutrient component of a microbiological medium?

A. zinc

48

An agent that kills pathogenic bacteria but not necessarily other kinds of microorganisms is known as a/an

D. germicide.

49

Who is associated with “tumble” and “dart” or “twiddle” and “run”?

D. Howard Berg

50

The dominant colonization of the oceans of Planet Earth by cyanobacteria

B. rusted most of the iron on the planet.
C. made aerobic life possible.
D. caused iron to shift from the ferrous to the ferric ion

51

Which is the most effective antibiotic

A. tetracycline

52

A laminar flow biocontainment hood secondarily depends on which technology to establish a sterile environment

A. UV radiation to control microbes on surfaces

53

Surfactants used for disinfection

C. quaternary ammonium compounds.
D. may form micelles

54

Who, of the below, dealt with issues as to whether proteins were “integral” or “peripheral” to lipid bi-layers of unit membranes of all Domains of Life?

A. Singer, Nicholson

55

ABC–powered transport AND proton pump/ H+ symport and antiport transport mechanisms are

B. examples of active transport

56

Germicidal ultraviolet radiation

A. kills pathogenic bacteria.
B. disrupts DNA structure
C. is typically around 260 nm wavelength.

57

Slime polysaccharides of bacteria

B. are similar to capsules but less defined.
C. protect from phagocytosis

58

Which of the below contains 2-ketodexoxyoctulonic acid?

A. lipopolysaccharide
B. gram-negative bacteria

59

The O antigen of bacteria is a component of which material of prokaryotic cell envelopes?

C. outer membrane

60

Which is/are better antimicrobial agents at 70% than at 100%?

D. some alcohols

61

Group translocation of a sugar into a bacterial cell

A. is active transport.
B. imports a phosphorylated sugar.

62

diplococcus

A. Streptococcus pneumoniae, Neisseria gonorrhoeae

63

bacillus

E. Mycobacterium tuberculosis, Bacillus anthracis

64

spirillum

C. Vibrio cholerae, Spirillum lipoferum

65

spirochete

B. Treponema pallidum

66

The motion of eukaryotic flagella is coupled to hydrolysis of ATP

t

67

Biomass of viable bacterial cells may be estimated by quantifying protein content

T

68

Optical density of a suspension of bacterial cells is a good way to easily distinguish between viable and non-viable cells

F

69

It is possible to apply Koch’s postulates to any viral pathogen.

F

70

The endospore forms of some gram-positive bacteria are efficient reproductive mechanisms.

F

71

Cell walls of Archaea get their structural rigidity from peptidoglycan

F

72

The second law of thermodynamics supports the plausibility of perpetual motion machines

F

73

A microbiologist may use a medium with chemically undefined components because it is easier to prepare

T

74

Both gram-positive and gram-negative bacteria have an outer membrane

F

75

The peptidoglycan layer of gram-negative bacteria is thicker than that of gram-positive bacteria

F

76

The rotation of bacterial flagella is powered by a trans-membrane proton gradient

T

77

Optical density of a broth culture is directly proportionate to cell population density

T

78

An example of “decimating” a microbial population is to reduce it from 1000 to 100 microbes.

T

79

which is typicaly the physically smallest category of entities studied by microbiologist

viruses

80

which is true and grammaticlly correct

cocci= spheres
bacillus= rod
bacilli= rods
diplococcus= two cocci adjacent to each other

81

which of the below shook up biological science by discovering a new domain of life

george fox and carl woese molecular biologist

82

ubiquitous is most precissely and cincisely defined as

everywhere

83

life on earth would be much healthier and more pleasent if we could remove all bacteria from the planet

F

84

prions are cellular entities

F

85

Microorganisms are the only cellular based organism capable of spontanious generation; that is they routinly create new life from non living materials

F

86

bacteria is in and on your body out number all the mammals on earth

T

87

Which group below includes viruses?

E. Non-cellular biological entity.

88

Which of the above is the most-recently discovered biological domain

archaea

89

domain eukarya

C. has 18S rRNA genes

90

A culture of Escherichia coli is growing on a medium containing glucose and ammonia as sole C- and N-sources, inorganic salts that supply S, P, Mg, K, Na and precisely quantified trace nutrients. Which term best describes its mode of growth?

C. heterotrophy

91

Carl Woese and George Fox established that prokaryotic microorganisms should be classified into the separate domains Bacteria and Archaea based on...

B. 16S rRNA gene sequence differences.

92

Louis Pasteur was

A. formally trained as a chemist.
B. the discoverer of D- and L- tartaric acid.
C. developer of a treatment for rabies.
D. inventor of a heat-treatment to preserve foods.
E. All of the above.

93

Robert Koch

A. developed logical guidelines to establish microbial etiology of a disease.
B. discovered the cause of tuberculosis.
C. developed a better solidifying agent for solid microbiological media.
D. used Petri dishes.
E. did all of the above..

94

Which characteristic is NOT found in members of Domains Bacteria and Archaea?

E. double-unit-membrane bound organelles

95

Which of the following is a characteristic of active transport?

A. carrier/transport mechanisms that can be saturated to a maximum uptake rate
B. use of ATP, PEP, or proton motive force as a source of metabolic energy
C. can move materials against a concentration gradient
D. exhibits specificity for the molecule being transported
E. all of the choices

96

When the number of live cells produced equals the number of cells dying in a batch culture, the culture is in _______________phase.

E. stationary

97

The outer membrane of gram-positive bacteria is also known for its pharmacological effect as

A. exotoxin.
B. periplasm.
C. peptidoglycan.
D. endotoxin or pyrogen.
E. none of the above.

98

Which group(s) has/have fatty acids linked to glycerol by ester bonding?

D. Bacteria and Eukarya

99

Periplasmic space

C. between cytoplasmic membrane and outer membrane of prokaryotes

100

Which of the below contains Lipid A?

A. lipopolysaccharide

101

The ability of microorganisms to biodegrade essentially all natural organic compounds has been described as

C. microbial infallibility.

102

Lysozyme is active against which of the below?

bacteria

103

What term best describes the medium on which the above E. coli culture is growing?

defined

104

The movement of molecules across a membrane from an area of higher concentration to an area of lower concentration with the use of a carrier molecule embedded in the membrane is called

A. facilitated diffusion.

105

Proteins that are intimately associated with the cytoplasmic membrane are called __________ proteins

B. integral

106

“Lophotrichous” is a term that can apply to

C. a cluster of flagella at one or both ends of an organism

107

Some organisms studied by microbiologists are larger than a pizza.

T

108

Microorganisms are the only cellular-based organisms capable of spontaneous generation; that is, they can create new life from non-living materials.

FALSE

109

Axenic cultures may be pure cultures or mixed cultures.

T

110

Pure cultures may be obtained by various dilution techniques, one of which includes streaking a plate of agar medium

T

111

Flagella of eukaryotic microbes whip like snakes and driven by hydrolysis of ATP

T

112

Motility driven by flagella is the only mechanism of motility found in prokaryotic microbes

F

113

Which is NOT true concerning prokaryotic plasmids?

They may be composed of RNA

114

Approximately what percentage of Domain Bacteria are estimated to be culturable?

.1%

115

Who of the following developed a set of criteria that could be used to establish a causative link between a particular microorganism and a particular disease?

koch

116

Ultra violet radiation that is germicidal

A. is approx. 254 nm wavelength

117

The class of compounds known as surfactants

A. may be microbicidal.
B. disrupt lipid membranes.
C. reduce interfacial tension between hydrophobic and hydrophilic materials (e.g., oil and water) and lower the surface tension of water.
D. may be synthesized by microorganisms to allow easier biodegradation of hydrophobic materials.
E. have all of the above properties.

118

A closed flask of sterile broth is inoculated with 10 cells. The lag phase lasts 1 hour. After 2 hours of log phase growth, the population increases to 640 cells. The approximate number of generations that has occurred is

6

119

Which of the following is NOT a method of heat sterilization?

pasteurization

120

An agent that specifically kills algae but not other kinds of microorganisms is known as a/an

algicide

121

Penicillin is active against which of the below?

bacteria

122

Who worked with Richard Petri and Fannie Hesse to develop solid media and plates for purifying microbiological cultures?

robert koch

123

Inoculum-dependent growth lag (higher the starting population, shorter the lag) may be a consequence of

A. quorum sensing of microbes that enhances their ability to respond to their environment.
B. necessity of getting effective concentrations of hydrolytic enzymes into the environment.
C. necessity of getting effective concentrations of siderophores into the environment.
D. all of the above.

124

Which culture regime can maintain log-phase cells indefinitely?

C. continuous culture

125

ABC–powered transport

A. is active transport
C. requires ATP.

126

The MIT (Madonna-Inspired Technology) is a type of control of microbes

A. depends on air filtration.
B. maintains sterility.
C. will work at room temperature.
D. All of the above

127

A microorganism that has a growth optimum near the freezing point of water is best described as

psychrophile.

128

The physical parameter affecting a bacterium that is being autoclaved and eventually kills it is

heat

129

After one applies a chemical to sanitize a working surface in a food preparation area

B. the surface may be sterile.
C. the surface may not be sterile.
D. the surface may meet public health standards.

130

The term describing the condition in which microorganisms survive and grow under very low nutrient concentrations is

oligotrophic

131

The study of bioinformatics and the analysis of genomic information of microorganism is most efficiently conducted

in silio

132

Which is the most effective antibiotic?

penicillin

133

A laminar flow biocontainment hood primarily depends on which technology to establish a sterile environment?

C. high-efficiency particulate air filters

134

Which is a gas used as a microbicide in soils?

methyl bromide

135

Escherichia coli is best described as having which morphology?

bacillus

136

Which is a better antimicrobial at 70% than at 100

ethanol or isopropanol

137

Which of the below developed the fluid mosaic model for membrane structure?

C. Singer, Nicholson

138

Which potential transport mechanism does NOT exhibit substrate saturation?

simple diffusion

139

Peritrichous” is a term that can apply to

D. a relatively even distribution of flagella over the entire surface of the bacterium.

140

The O antigen of gram-negative bacteria is a component of which material?

A. lipopolysaccharide

141

Synchronous growth of bacteria

A. occurs when most cells in a culture are dividing in synchrony with each other.
B. is difficult to maintain for more than a few generations.
C. may be achieved by the Helmstetter-Cooper method.
D. All of the above

142

When Vibrio fischerii colonizes the surface of a small squid, it “decides” whether or not to turn on bioluminescence by using a regulatory mechanism termed

E. quorum sensing.

143

Surfactants used for disinfection include

A. detergents.
B. soaps.
C. quaternary ammonium compounds.
D. all of the above

144

The dominant colonization of the oceans of Planet Earth by cyanobacteria

A. rusted most of the iron on the planet.
B. made aerobic life possible.
C. caused iron to shift from the ferrous to the ferric ion.

145

Which element below might be a catalytic-level or a micronutrient component of a microbiological medium?

B. molybdenum

146

Which would be the method of choice for sterilization of heavy bedding (blankets, mattresses)?

ethyene oxide

147

Biological amino acids are typically L-amino acids; which prokaryotic cell component contains D-amino acids?

peptidoglycan

148

If one applies dry heat to sterilize glass

A. a temperature higher than that of an autoclave will be required.
B. there will be no living organisms on the pipettes.
C. there will be no pathogenic organisms on the pipettes, and even heat-resistant spores will be killed.

149

Group translocation of a sugar into a bacterial cell

A. is active transport.
B. imports a phosphorylated sugar.

150

The minimal effective concentration of a new Disinfectant X kills a standard suspension of Staphylococcus aureus at a dilution of 1:100; phenol produces the same killing effect at a dilution of 1:10. What is the phenol coefficient of the new Disinfectant X?

10

151

The minimal effective concentration of Disinfectant Y kills a standard suspension of Staphylococcus aureus at a dilution of 1/1000; phenol produces the same killing effect at a dilution of 1/25. What is the phenol coefficient of phenol?

1

152

Cyanobacteria appeared on Planet Earth

over 2 billion years ago

153

If you pass an inoculation loop through a flame to heat it to incandescence, it becomes

A. sterile
B. sanitary
C. disinfected
D. hot

154

Capsular polysaccharides of bacteria have which of the following possible functions?

A. food storage
B. virulence factor
C. protection from phagocytosis

155

Antibiotics are evaluated by which method?

Kirby-Bauer method

156

Which of the below contains 2-ketodexoxyoctulonic acid?

lipopolysaccharide

157

Compounds secreted outside microbial cells with an extremely high affinity for binding ferric iron are called

siderophores

158

Chemotherapeutic agents are most importantly

A. specifically targeted to a pathogen and relatively harmless to the host

159

What are potential limitations of applying Koch’s Postulates?

A. Ethics of inoculating animals or humans with pathogens
B. Inability to grow some organisms on artificial medium
C. Inability to isolate microbial pathogen in pure culture
D. Inability to maintain virulence of a pathogen outside of the animal or plant host

160

A filter capable of removing essentially all bacteria from a liquid will have approximately what pore size?

C. 0.2 µm

161

The concept that human and animal diseases are caused by microorganisms is called the

germ theory

162

Quaternary ammonium compounds are a class of disinfectants that are known as cationic surfactants.

TRUE

163

Bacteria tumble by twirling their flagella in one direction and dart or run by twirling their flagella in the opposing direction

TRUE

164

Marshall and Warren won a Nobel Prize for their application of Koch’s Postulates to establish Helicobacter pylori as the etiological agent of gastric and pyloric ulcers

TRUE

165

Active transport driven by exchange of K+ for H+ across a membrane is powered by a potassium-proton “antiport.”

TRUE

166

ABC- transport mechanisms derive their energy directly from hydrolysis of adenosine triphosphate

TRUE

167

A microbiologist may use a chemically undefined, complex medium because it is easier to prepare.

TRUE

168

Both gram-positive and gram-negative bacteria have an outer membrane

FALSE

169

Microbiologists study a variety of organisms, but all are considered members of either Bacteria or Archaea.

FALSE

170

Gram-positive bacteria have a thicker layer of peptidoglycan than gram-negative bacteria.

TRUE

171

The rotation of bacterial flagella is powered by ATP hydrolysis

FALSE

172

Fatty acids in membrane lipids of members of Archaea are coupled to glycerol by ester bonds.

FALSE

173

Optical density of a broth culture is directly proportionate to cell population density.

TRUE

174

Chlorine bleach kills bacteria by means of an oxidizing agent

TRUE

175

Escherichia coli, Bacillus subtilis, B. anthracis, and Azotobacter vinelandii are all gram-positive bacteria that produce endospores

FALSE

176

Inspisation is a means of sterilizing media without denaturing heat-labile components that relies on ionizing radiation.

FALSE

177

Microbiologists streak because they know that nudity is the natural state of humans and nothing to be ashamed of.

FALSE

178

Antibiotics are the only class of materials that can serve as chemotherapeutic agents

FALSE

179

To decimate a microbial population is to wipe out 90%.

TRUE