Lab Final Flashcards
(211 cards)
1
Q
Objects appear upside down and backwards through a microscope .
A
true
2
Q
Use both hands to carry the microscope; keep the instrument upright.
A
true
3
Q
The ___________ is a device invented in the seventeenth century for magnifying objects that are too small to be seen with the naked eye.
A
microscope
4
Q
To save time, look through the microscope and rapidly bring the objective lens and the specimen together by rotating the coarse-adjustment knob.
A
false
5
Q
The microscopists measures ocular micrometer disk divisions with the stage micrometer.
A
true
6
Q
When utilizing a stage micrometer scale marked in 0.01 mm, the following formula holds true: (stage divisions/ocular divisions) x (0.01 mm/stage division) = millimeters per ocular division.
A
true
7
Q
The ______ _______ gives microscopists a mathematical way of describing the light-gathering ability of a lens system.
A
numerical apenture
8
Q
Most modem microscopes are parfocal. This means the microscopist can add infinitely more lens systems for greater magnification and resolution.
A
false
9
Q
A compound microscope contains two or more sets of lenses.
A
true
10
Q
Always be sure to oil your microscope lenses before returning the instrument to its designated space.
A
false
11
Q
The space separating a specimen and the objective lens is called ________ distance
A
working
12
Q
The stage micrometer scale is generally ruled to 0.0001 mm.
A
false
13
Q
The objective lens is the one nearest the observer’s eye.
A
false
14
Q
Immersion oil has nearly the same refractive index as glass.
A
true
15
Q
The numerical aperture of an objective lens depends on the size of the cone of light it can receive and also upon the medium in which the lens is suspended.
A
true
16
Q
A specimen is normally placed on top of the stage micrometer and measured with the tiny ruler that is etched onto the stage micrometer.
A
false
17
Q
Which microscopist showed the mathematical relationship between resolution and the ability of a lens to gather light?
A
Ernst Abbe
18
Q
Which microscopist published the first drawings of bacteria in 1676?
A
Anton van Leeuwenkoek
19
Q
Lens paper can be used to remove oil from the glass components of the microscope.
A
true
20
Q
To calculate the total magnification of your microscope, add the magnifications of the objective and ocular lenses.
A
false
21
Q
The area that you see through a lens is the microscopic ________
A
field
22
Q
Increasing the size of a blurred image generally reveals further details.
A
false
23
Q
If a lens is designed to be used with immersion oil, it is able to gather more light when the oil is utilized than when air separates the lens from the specimen.
A
true
24
Q
Resolving power is the ability to rotate a new objective Jens into the observation position and have the field remain in focus.
A
false
25
When utilizing a stage micrometer scale marked in 0.01 mm, the following formula holds true: (stage divisions/ocular divisions) x (10 um/stage division) = micrometers per ocular division.
true
26
Before vortexing bacterial cells in a broth culture, always remove the test tube closure.
false
27
Coccobacilli are cocci; palisades are groups of four cocci.
false
28
Smears should be air dried before they are heat fixed.
true
29
Heat fix bacterial smears by holding the slide in the hottest part of the flame for 2 minutes.
false
30
The decolorization in the Gram stain is Gram's iodine.
false
31
In the Gram stain procedure, what is the color of gram-negative bacteria after the primary stain?
purple
32
Water rinses should not be left on the smear too long during the gram stain procedure because water slowly decolorizes stained cells.
true
33
A cation has a positive charge; chromophores are always anions.
false
34
An aqueous solution is made with water.
true
35
The primary stain in the Gram stain is crystal violet.
true
36
The cell wall of a gram-negative bacterium contains lipoprotein and lipopolysaccharide.
true
37
The peptidoglycan layer of a gram-negative cell wall is thicker than the corresponding layer of a gram-positive cell wall.
false
38
In the Gram stain procedure, what is the color of gram-positive bacteria after decolorization?
purple
39
In the neutral environment of most microbiological dyes, bacteria generally carry a net negative charge.
true
40
Gram-positivity is a characteristic that is easily lost.
true
41
In the Gram stain procedure, what is the color of gram-negative bacteria after the mordant (iodine)?
purple
42
Aniline dyes are derived from benzene, a coal tar derivative.
true
43
The chromophore of a basic dye carries a negative charge.
false
44
In the Gram stain procedure, what is the color of gram-negative bacteria after the counterstain stain?
pink
45
The decolorization is applied before the mordant in the Gram stain procedure.
false
46
The cell wall of gram-positive have a thick layer of peptidoglycan associated with teichoic acids.
true
47
In the Gram stain procedure, what is the color of gram-positive bacteria after the primary stain?
purple
48
A slide is clean enough for bacteriological smears if water coalesces on it.
false
49
A chemosynthetic organism is able to construct cellular molecules out of carbon dioxide and oxygen.
false
50
Antibiotic sensitivity testing is performed with pure cultures.
true
51
what is the term for devoid of life
aseptic
52
what is the term for A combination of various microbial species living together
mixed culture
53
what is the term for One kind of bacteria, ideally the descendants of one cell, living together
pure culture
53
what is the term for the introduction of unwanted organisms
contamination
53
what is the term for free from disease-producing microorganisms
sterile
53
Many cyanobacteria fix gaseous nitrogen.
true
54
Sterile techniques are generally utilized with broth cultures; aseptic techniques are reserved for solid media work.
false
55
Flaming sterilizes by incinerating organisms.
true
56
Rotifers are protozoa.
false
57
Endospores are resting or survival structures.
true
58
Heterotrophic organisms require organic molecules for a carbon source.
true
59
Aseptic techniques are performed only for their traditional value. In a modem microbiology laboratory, microbes are electronically removed from the air, workbench, inoculation instruments, and hands.
false
60
Microbiology laboratories often maintain stock cultures. These stocks are pure cultures.
true
61
Unstained Treponema pallidum is too thin to be observed with a compound, light, bright-field microscope.
true
62
In a microbiology laboratory, it is generally safe to mouth pipet since most microorganisms are not killed by exposure to exhaled air.
false
63
A photosynthetic organism is able to make cellular energy out of light energy.
true
64
Alcohol-flaming can be employed to sterilize the tips of forceps.
true
65
An aerosol is a visible clump of bacteria suspended in proteinaceous matter such as sputum.
false
66
When transferring bacteria from a solid surface, be sure to gouge the agar, digging out the entire colony where it has burrowed into the medium.
false
67
To help identify a bacterial species, a microbiologist usually performs biochemical tests on the mixed culture.
false
68
Factors that limit the amount of growth in a broth culture include size of inoculum, availability of nutrients, temperature and duration of incubation, presence of oxygen, concentration of toxins, and so on.
true
69
Some rods are called diphtheroids because they resemble Corynebacterium diphtheriae.
true
70
Select organisms with a eukaryotic cell or cells. (3)
Bacteria (including cyanobacteria)
protozoa
multicellular invertebrates
algae
algae
protozoa
multicellular invertebrates
71
which group contains endospores
bacteria (including cyanobacteria)
72
Bacteria moving toward oxygen are displaying negative phototaxis.
false
73
To focus on unstained, transparent cells, reduce illumination of the field far below the levels used with stained cells.
true
74
A saprophytic organism usually parasitizes living tissue, causing disease and death.
false
75
what has a prokaryotic cell
bacteria
76
Alcohol-flaming should always be performed over a stack of papers so that the dripping alcohol does not burn the workbench.
false
77
Daphnia is an alga.
false
78
During alcohol-flaming, the tips of the forceps are not held in the burner flame until they are red-hot.
true
79
In nature most microorganisms are found in mixed cultures.
true
80
Spirochetes are rigid, inflexible, spiral-shaped bacteria; spirilla are flexible, spiral-shaped bacteria.
false
81
If an organism lacks a nuclear membrane but is green and produces oxygen, it is probably a member of which group?
bacteria
82
To preserve purity, handle cultures as little as possible. Open them all at the beginning of the laboratory period; close them once, before leaving the area.
false
83
Inoculating needles and loops are generally constructed of Nichrome or platinum wire.
true
84
Worms are multicellular invertebrates.
true
85
Pairs of cocci are called packets.
false
86
The energy of life produces order and dispels entropy.
true
87
In a pour plate, colonies develop throughout the medium.
true
88
Colonies are smaller in crowded areas of a pour plate than in areas where they are well separated.
true
89
Lenticulate colonies are usually found on the surface of a pour plate.
false
90
In microbiology laboratories, colonies are usually counted to determine the number of bacteria per milliliter of the original sample.
true
91
A countable plate has between 1 and 300 colonies.
false
92
The physiological characteristics of an organism are its Gram stain reaction.
false
93
In a serial dilution, each tube contains the same dilution as the previous one.
false
94
To fulfill Koch's postulates, a researcher must cultivate a mixed culture of organisms from the blood of a diseased experimental animal.
false
95
Koch's postulates are used to prove that a specific microorganism causes a specific disease.
true
96
Robert Koch was a pioneer of medical microbiology.
true
97
In a sample of human sputum or feces, you usually find a mixture of many different kinds of organisms.
true
98
In samples from nature, bacteria are usually found in mixed culture.
true
99
The two most common methods that separate individual bacteria from each other are the pour plates and lawns.
false
100
Be sure to flame your swab after preparing a spread plate.
false
101
Bacterial sensitivity to antibiotics is often tested on a spread plate.
true
102
Bacteriophage are special bacteria that are grown in spread plates.
false
103
All bacterial colonies look alike. Only staining reveals differences between genera.
false
104
The area of confluent growth is where colonies overlap and grow together.
true
105
The progeny of a single cell may form a colony, a visible clump of growth, on the surface of an agar medium.
true
106
Streaking a plate involves drawing a loopful of organisms back and forth across a solid medium in a Petri dish until the microbes fall off the loop one at a time.
true
107
A bacterial concentration gradient is a well-dispersed mixture of bacteria, thoroughly suspended in a broth culture.
false
108
When preparing a bacterial spread plate, swab a pure culture of bacteria evenly over the entire surface of an agar medium in a Petri dish.
true
109
To prepare a streak plate, spread bacteria evenly over the entire surface of a plate of medium.
false
110
Neisseria gonorrhoeae and Haemophilus influenzae are generally incubated in a candle jar.
true
111
Host-specific phages can distinguish one strain of a single bacterial species from another strain of the same species.
true
112
Bacteria are used to treat virus strains (with ice packs and tiny Ace bandages) in bacteriophage typing.
false
113
Since there is oxygen in the air that surrounds earth, being an aerobe is a great advantage for microorganisms in nature.
false
114
In a broth-clearing assay, the titer of phage in the original coliphage sample equals the end-point tube's dilution.
false
115
A plaque assay is designed to discover the number of bacteria in a viral solution.
false
116
Loosen the caps of screw cap tubes before incubating oxygen-utilizing bacteria in them.
true
117
After inoculating a tube of Fluid Thioglycollate Medium, shake the tube thoroughly to aerate and separate the bacteria.
false
118
Fermentation does not require oxygen.
true
119
Cultivation of viruses in tissue culture is generally as quick, inexpensive, and convenient as growing bacteria in nutrient media.
false
120
Viruses are classified by host, nucleic acid, size, shape, and presence or absence of an envelope.
true
121
The enzyme that catalyzes the reaction 2H2O2 -> 2H2 + O2 is superoxide dismutase.
false
122
Fermentation releases some but not all of the energy in organic compounds.
true
123
Coliphage are common microbiological laboratory "weeds" that infect all human pathogens.
false
124
The titer (concentration) of virions in your original coliphage sample equals the number of plaques on a countable plate times the inverse of that plate's dilution.
true
125
To prepare an agar shake culture, boil the medium, solidify it, and then inoculate it with a clean stab to the bottom of the tube.
false
126
After incubation, the sealed redox potential indicator envelope is removed from a GasPak jar and opened.
false
127
A redox potential is the opposite of an oxidation reduction potential; when one is high the other is low.
false
128
To prepare a coliphage plaque assay, add Escherichia coli strain B to Soft Agar overlays, add dilutions of a virulent coliphage, pour the overlays into Tryptic Soy Agar in Petri dishes, incubate appropriately, then examine for liquefaction of the Soft Agar.
false
129
A candle jar contains the best mix of gases available for culturing anaerobes.
false
130
Pasteur discovered anaerobes, microorganisms that are poisoned by oxygen.
true
131
A plaque-forming unit represents one bacterial cell.
false
132
Fluid Thioglycollate Medium is pink in the bottom of the tube where the resazurin is highly reduced.
false
133
Viruses are defined as "cellular" because they replicate inside of living host cells.
false
134
Bacteria that are exposed to air as they grow are generally in a highly reduced envrionment.
false
135
Spread a thick layer of petroleum jelly around the O-ring of a GasPak jar before sealing the lid.
false
136
A viral plaque is a hole in a confluent layer of permissive host cells.
true
137
Anaerobes grow in reduced environments.
true
138
If nitrite is missing from an incubated culture tube of Nitrate Broth, it may indicate that the bacteria did not produce nitrate reductase.
true
139
Proteus is urease-positive; Salmonella and Shigella are urease-negative.
true
140
Denitrification is the complete oxidation of NO-3 to form nitrogen gas.
false
141
Facultatively anaerobic bacteria generally do not produce nitrate reductase.
false
142
Endoenzumes speed reactions outside of cells.
false
143
Urease catalyzes the reduction of NO-3; nitrate reductase catalyzes the hydrolysis of NO-2.
false
144
Probes are pieces of nucleic acid that scientists sometimes use to identify microbes.
true
145
Proteus is generally nonpathogenic in the human intestine, but it is a common cause of urinary tract infections.
true
146
On Starch Agar a darkened area indicates starch hydrolysis.
false
147
Cytochrome oxidase is produced by Pseudomonas but not by members of the Enterobacteriaceae.
true
148
Egg yolk contains the phospholipid lecithin (choline phosphoglyceride), an emulsifying agent. About two-thirds of the dry weight of egg yolks is lipid.
true
149
To analyze the reactions of bacteria growing on Starch Agar, flood the plate with 3% hydrogen peroxide.
false
150
Any bacteria that grow on a plate of Starch Agar are amylase producers.
false
151
An oxidase is an enzyme that oxidizes compounds.
false
152
Enterococcus, Streptococcus, and Lactobacillus tolerate oxygen and produce catalase.
false
153
Gelatin suspensions are in the gel state below 25 degrees C.
true
154
In a Nitrate Broth culture, if zinc reduces nitrate to nitrite, then the bacteria in the tube did not.
true
155
All bacteria that utilize desulfhydrases produce hydrogen sulfide, rotten egg gas.
true
156
Catalase helps Staphylococcus aureus poison mayonnaise by attacking fat molecules.
false
157
Cysteine desulfhydrase yields hydrogen sulfide, hydrochloric acid, and pyruvic acid.
false
158
Hydrogen peroxide is toxic to cells, but it is also a common by-product of reactions that accompany aerobic respiration.
true
159
Some exoenzymes break down molecules that are too large to cross a cell membrane.
true
160
Urea is a protein.
false
161
Amylases hydrolyze starch by adding the Na+ and CI- ions of H2O.
false
162
Lipids are found in all cell membranes.
true
163
Along with other information, DNA carries the genetic code for all the enzymes that a microorganism produces.
true
164
Starch is a large, many-branched polymer of the monosaccharide glucose.
true
165
Urea is toxic to most cells, but urease producers can degrade this nitrogen-containing compound.
true
166
Microbial physiology is the study of the size, shape, arrangement, and staining reactions of bacteria.
false
167
The black precipitate that may form in a test tube containing Triple Sugar Iron Agar consists of H2S.
false
168
Clostridium tetani toxin kills with the rigid paralysis of tetanus.
true
169
Since agar media are largely water, a water-soluble microbial pigment tints the agar as well as the colony.
true
170
The most deadly biological nerve toxin known is botulism toxin.
true
171
A colony is an individual bacterial cell.
false
172
All endospores are terminally located in swollen sporangia.
false
173
Endospore-forming bacteria produce the ____________________ antibiotics that inhibit cell wall synthesis.
bacitracin
174
Conditions of incubation include temperature, pH, and salinity, but not the medium and its nutrients.
false
175
The Schaeffer-Fulton endospore-staining procedure employs ethyl alcohol and phenol to drive malachite green into endospores.
false
176
After staining with the Schaeffer-Fulton endospore procedure, endospores appear pickle green while vegetative cells are periwinkle blue.
false
177
Endospores preserve life in a/an __________
state with no measurable metabolic activity.
cryptobiotic
178
Bacillus anthracis is the etiologic agent of anthrax.
true
179
When the scientific method of investigation is employed, only experiments that prove the accuracy of the original hypothesis are useful.
false
180
Opaque means translucent.
false
181
A control is a test in which only one factor is different than in the experiment.
true
182
Endospores in cooked food may germinate at room temperatures and lead to food poisoning.
true
183
Bacterial endospores are hard, dry structures that burst forth as external buds on certain genera of flowering rods.
false
184
The appearance of a colony reflects the biochemistry of the species that formed it, so all bacterial colonies look alike.
false
185
Which is the decolorizer in the Schaeffer-Fulton endospore-staining procedure?
water
186
Which is the primary dye used in the Schaeffer-Fulton endospore-staining procedure?
malachite green
187
In the Schaeffer-Fulton endospore stain, which of these is the counterstain?
safranin
188
Which of these is a common aniline dye used by microbiologists but not employed in the Schaeffer-Fulton endospore-staining procedure?
methylene blue
189
When utilizing the scientific method of investigation, you must first recognize a problem or situation and then gather information concerning it.
true
190
Scrubbing the hands with antiseptic solution and a brush for 40 seconds always kills all bacteria on the cleansed area.
false
191
Soap cleans by chemically linking oil to grease.
false
192
Soaps are formed when fats are heated in the presence of an acid such as hydrochloric acid.
false
193
The carboxylate end of a soap molecule is soluble in the hydrocarbons, the oily end in water.
false
194
Washing hands usually reduces their microbial load of transient flora.
true
195
Any cleansing solution, including soap, is a detergent.
true
196
If 38 colonies develop on a 10-6 dilution plate, it seems likely that between 0 and 5 colonies might grow on a 10-5 plate prepared from the same original suspension of bacteria.
false
197
Thoroughly scrubbing the hands and fingernails with hot soapy water for 1 minute removes all bacteria from the area cleansed.
false
198
Filtration and cultivation of colonies on a filter will determine __________________________The measurement of optical density will measure ___________________ Spread plate colony count is used for ____________________
Fit 1 from either: quantification of viable microorganisms only. Quantification of both viable and nonliving microorganisms.
Filtration and cultivation of colonies on a filter will determine quantification of viable microorganisms only.
. The measurement of optical density will measure
quantification of both viable and nonliving microorganisms.
. Spread plate colony count is used for
quantification of viable microorganisms only.
199
Soap forms a chemical link between oil and water.
true
200
Only a living colony-forming unit forms a colony.
true
201
Hand washing by medical personnel helps reduce the patient's risk of nosocomial (hospital-acquired) infections.
true
202
A colony-forming unit may be a single cell or a clumps of bacteria.
true
203
During saponification a sodium salt of an acid is produced
true
204
The soapy scum that forms in oily, hard water removes bacteria when it sinks to the bottom of the liquid, weighted down by its load of heavy mineral salts.
false
205
If you pour 15 ml of agar medium into a Petri dish that contains 1 ml of a 10-6 bacterial dilution, the dilution of the plate is still recorded as 10-6.
true
206
Saponification is a highly complex chemical process, but soap making is fairly straightforward.
false
207
Estimation of microbial population size are useful for industrial microbiologist but are of little value to the medical or public health microbiologist.
false
208
