MCB 2010L- LAB Test 1
How many life forms does Chlamydiae have and what are they
2 elementary body and the reticulate body
Bacterial cultures are incubated at
37 C
180. The correct order of the gram stain procedure is: A. crystal violet-iodine-ethanol-safranin B. safranin-crystal violet-iodine-ethanol C. iodine-safranin-crystal violet-ethanol D. crystal violet-ethanol-iodine-safranin E. crystalviolet-iodine-safranin-ethanol
A. crystal violet-iodine-ethanol-safranin
158. Congo red and India ink are ____stains A. negative B. neutral C. basic D. positive E. C and D
A. negative
27. Define ubiquitous A. Present everywhere B. Present nowhere C. All of the above D. None of the above
A.Present everywhere. (omnipresent)
165. The following is/are methods to examine flagella provide motility to the cell. A. negative stain B. electron microscopy C. Ryu stain D. B and C E. A, B, and C
B and C
147. Escherichia, Pseudomonas, Rhizobium, Salmonella and Spirillum are genera of: A. Actinobacteria B. Proteobacteria C. Cyanobacteria D. Streptomyces E. Firmicutes
B. Proteobacteria
155. Crystal violet is a ______ stain. A. negative B. neutral C. basic D. positive E. C and D
C and D; basic and positive
146. Mycobacterium and Streptomyces are genera of: A. Cyanobacteria B. Proteobacteria C. Actinobacteria D. Streptomyces E. Firmicutes,
C. Actinobacteria
28. Characteristics of a pure culture include: A. All colonies have the same textures B. All colonies have different margins C. All colonies have the same elevations D. All colonies have different pigment E. None of the above
C. All colonies have the same elevations
119. Why must the spore stain include a heating step? A. Cooking safranin into the resistant endospore allows its visualization B. Cooking congo red into the resistant endospore allows its visualization C. Cooking malachite green into the resistant endospore allows its visualization D. Cooking malachite green into the resistant endospore prevents its visualization E. None of the above
C. Cooking malachite green into the resistant endospore allows its visualization
116. What is the clinical value of an acid-fast stain? A. Rapid identification of Clostridium B. Rapid identification of Bacillus C. Rapid identification of Mycobacterium D. All of the above E. None of the above
C. Rapid identification of Mycobacterium
177. Gram stained Mycobacteria appear blue/purple
true
58. Microbial colonies can be colored/pigmented because of loss of nutrients and carbohydrates to the growth media
true
87. A counterstain (methylene blue) is used to see them non acid fast bacterium
true
Flame inoculating tools using the Bunsen burner until they are red hot in order to sterilize
true
101. The number of flagella and their arrangement can be defined as: A. Monotrichous B. Amphitrichous C. Lophotrichous D. Peritrichous E. All of the above
E. All of the above
156. The following is a bacterial stain A. safranin B. methylene blue C. crystal violet D. malachite green E. All of the above
E. All of the above
Methods to prevent contamination include: A. flaming B. autoclaving C. sterilizing D. use of steam under pressure E. all of the above
E. All of the above
120. What would happen if the heating step were omitted from the spore stain? A. The endospore would be green B. The endospore would be blue C. The endospore would be black D. The endospore would be red E. The endospore would be clear
E. The endospore would be clear
26. Define colony: Macroscopic bacterial growth on solid media B. Microorganisms all originating from a single mother cell C. Bacterial clones D. Genetically identical bacteria E. All of the above
E. all of the above
The following are not allowed in the lab: A. food B. drink C. children D. smoking E. All of the above
E.All of the above
135. Bacillus, Clostridium, Lactobacillus, Staphylococcus and Streptococcus are genera of: A. Actinobacteria B. Proteobacteria C. Cyanobacteria D. Streptomyces E. Firmicutes
E.Firmicutes
131. Firmicutes and Actinobacteria are two bacterial A. Families B. Genera C. Classes D. Orders E. Phyla
E.Phyla
118. What is the importance of the different arrangements of flagella? A. Pathogenicity B. Attachment C. Speed D. Virulence E. Locomotion
E.locomotion
170. When using growth from an agar medium to make a smear, a loopful of water is placed on the slide, and a very large amount of culture is mixed with the water to separate and suspend the bacteria. The suspension is then spread out, air dried, and heat fixed. In a good smear, the bacteria are evenly spread out on the slide and individual organisms are visible microscopically.
False
181. Crystal violet is used as the primary stain in the gram stain procedure because it contains an anionic ion that binds to the cell wall of both gram-positive and gram negative cells because the cell walls of both are negatively charged.
False
32. Colony morphology is identical between various microbial species
False
39. Mycobacterium, Mycoplasma, Chlamydia, and Rickettsia are not classified as true bacteria
False
Blow on the sterilized inoculating tools to cool them
False
True/False: All of the organisms we work with are pathogenic
False
25. Most bacterial cultures will be incubated at 55°C for 24 to 48 hours
False. 37 C
33. Colony morphology does not vary with microbial growth conditions
False. Does vary
Species of Rickettsia can cause pneumonia, urogenital and other infections and are normally found in normal mucous membrane microflora
False. Mycoplasma
62. In colony morphology, 'size' relates to the size of the bacterial cell
False. Relates to the size of the colonies
18. Test tubes are fitted with loose caps that will not come off, so you can hold the tube by the cap
False. always hold the tube not the cap
51. Most Rickettsiae are transmitted by arthropods like bats
False. by insects and tick bites
63. To examine size, observe colonies in the most densely populated quadrant of the plate (e.g., first quadrant)
False. examine from sparsest area
67. To observe elevation, it is best to look at the top of your plate
False. from side of the plate
66. To observe elevation, it is best to look at the bottom of your plate
False. from the side of the plate
49. Rickettsiae have a cell wall that cannot be stained.
False. gram- negative and pleomorphic = no cell wall
Typically growth media is sterilized by flaming
False. in an autoclave/ steam under pressure
In the lab long hair must be tied back and loose clothing should be worn
False. loose clothing is flammable
Never lay tubed media down vertically, at anytime—it will spill.
False. never lay horizontally
Non-contaminated waste goes into the autoclavable bags. Contaminated disposable waste goes into the waste basket.
False. non-contaminated waste to the waste basket. Contaminated waste to the autoclavable bags.
53. Chlamydiae are motile, coccoid, obligate intracellular parasites.
False. non-motile
54. Chlamydiae have three life forms, or stages, known as the elementary body, primary body and the reticulate body.
False. only two life forms; elementary bodies and reticulate bodies.
15. An axenic culture is a mixed culture of organism of interest.
False. pure culture
An autoclave sterilizes by using halogenated gases
False. steam under pressure
59. If the organism produces an extracellular pigment the media turns colorless
False. the media becomes colored
44. Mycoplasmas are susceptible to the antibiotics which act by inhibiting cell wall synthesis.
False. they are resistant since they have no cell walls
Aseptic techniques are any techniques employed to encourage contamination.
False. to avoid contamination
True/False: Wash hands with disinfectant and wipe bench tops with soap and warm water before starting any lab exercise and after all work has been completed.
False. wash hands with soap and warm water. Wipe bench tops with disinfectant.
122. The currently accepted taxonomic system places all organisms into one of five Domains: Eukarya, Archaea, Bacteria, Fungi, Animalia
False; 3 domains: Eukarya, Archaea, and Bacteria
90. Often it will take 9 weeks for visible growth of Mycobacterium in culture.
False; 4-8 weeks
130. There are seven phyla of the Domain Bacteria.
False; 5 phyla
103. Endospore formation is most characteristic of two genera of bacteria, Bacillus and Mycobacterium
False; Bacillus and Clostridium
84. In the acid-fast stain, a green stain (carbolfuchsin) is cooked into the waxy cell wall, and cannot be removed with acidified alcohol.
False; a red stain
108. Endospores appear blue in red bacterial cells.
False; appear green
115. Endospores are reproductive germinating cells
False; are a resting structure formed inside some bacteria
72. Opaque colonies block none of the light. (True/False and if F, what is the right answer)
False; block all of the light
152. The dominant metabolic strategy of all five major phyla in the domain bacteria is oxygenic photosynthesis
False; chemoheterotrophy for firmicutes, acitinobacteria, proteobacteria, and chlamydia. Oxygenic photosynthesis for cyanobacteria
145. There are no disease-causing species of the genus Chlamydia
False; contains many disease- causing species
144. Phylum Chlamydiae bacteria do not have genes for production of peptidoglycan.
False; genes are present
89. Mycobacterium grows very fast in the laboratory on a complex media.
False; grows slowly
153. Actinobacteria have a low G + C content in DNA
False; have high G + C ratios
143. Phylum Chlamydiae is unique among bacteria in that its members have an abundance of peptidoglycan in their cell walls
False; have little to no peptidoglycan in their cell walls
125. Within each of the domains, a hierarchical taxonomic system places similar species into the same kingdom
False; into Genus
99. Flagella are tiny hairlike organelles for pathogenicity.
False; locomotion
111. Cooking safranin into the resistant endospore wall is used in the process of staining an endospore
False; malachite green
150. Wasserblüthe is a German word meaning 'water fall"
False; means "water bloom"
157. Bacterial cells have a positive charge
False; negative charge
68. In colony morphology, 'transparency' is how much light is able to pass through the colony
False; opacity
132. Firmicutes and Actinobacteria are generally Gram negative
False; positive
124. Prokaryotic cells have chromosomes that are contained in a true membrane-bound nucleus.
False; prokaryotes have no nucleus
138. Chlamydiae has the most genera (> 300) of any other bacterial phylum
False; proteobacteria has the most genera
167. Brownian motion is the ordered moving of particles resulting from their collisions with atoms or molecules in the water.
False; random
159. Staphylococcus sp. is arranged as chains and is rod shaped
False; staph=cluster. coccus= spherical
76. White colonies or translucent colonies that take on the color of the straw-colored media are termed "pigmented"
False; termed "nonpigmented"
40. Mycobacterium, Mycoplasma, Chlamydia, and Rickettsia are extremely large and cannot be cultured by ordinary methods. (Why)
False; they are small
105. Because of the weak spore coating, they are not readily stained and may appear as empty "holes" in simple or gram-stained bacteria.
False; tough spore coating
142. Rhizobium of the Proteobacteria use carbon fixation (in specialized cells called heterocysts) to convert gaseous carbon dioxide into a form they can use.
False; use nitrogen fixation
83. Fatty lipids called mycolic acids also prevent drying of the microbe.
False; waxy lipids
45. A type of colony morphology form includes A. Raised B. Convex C. Flat D. FILAMENTOUS E. UMBONATE
Filamentous
46. A type of colony morphology margin includes A. Raised B. Convex C. Flat D. FILAMENTOUS E. UMBONATE
Filamentous
Arthropods
Invertebrates with jointed appendages (bugs)
161. A/an ______ is a small glass disc with uniformly spaced lines etched on it.
Ocular micrometer
Rickettsia
Rocky Mountain Spotty Fever
102. A stain and mordant react with the flagella, increasing its diameter to allow viewing in the microscope.
True
104. Endospores provide a resistant form for survival of the organism in unfavorable conditions.
True
106. A special staining technique must be used to drive dye into endospores.
True
107. Usually malachite green is heated to stain the endospores, and then the vegetative bacteria are counterstained with safranin.
True
109. Boiling water is used in the process of staining an endospore
True
110. 15-20 minutes of steam is used in the process of staining an endospore
True
112. During the process of staining an endospore, running water washes the green stain out of the vegetative cells and sporangia, and they become colorless.
True
113. The counterstain then dyes the vegetative cells red (Endospores)
True
121. The science of taxonomy provides us with a system for classifying and naming organisms.
True
123. Domains Archaea and Bacteria contain all organisms with cells that are prokaryotic
True
126. Within each of the domains, a hierarchical taxonomic system places similar similar genera into the same family
True
127. Within each of the domains, a hierarchical taxonomic system places similar similar families into the same order
True
128. Within each of the domains, a hierarchical taxonomic system places similar similar orders into the same class
True
129. Within each of the domains, a hierarchical taxonomic system places similar and similar classes into the same phylum
True
133. Firmicutes and Actinobacteria differ from each other in the percentage of Guanine and Cytosine (G + C) bases (relative to Adenine and Thymine) in their DNA.
True
134. Firmicutes contains five key genera
True
136. Actinobacteria contains two key genera including Mycobacterium and Streptomyces
True
139. Proteobacteria contains five key genera: Escherichia, Pseudomonas, Rhizobium, Salmonella, and Spirillum.
True
140. The members of phylum Cyanobacteria, including the ke genus Anabaena, are unique in their metabolic strategy, utilizing oxygenic photosynthesis to obtain energy and organic carbon molecules.
True
141. Many of the Cyanobacteria also use nitrogen fixation (in specialized cells called heterocysts) to convert gaseous nitrogen into a form they can use A. TRUE
True
149. Phylum Cyanobacteria contains genera Anabaena which utilizes heterocysts for nitrogen-fixation
True
151. When looking at a slide of Wasserblüthe, you will observe many different types of Cyanobacteria.'
True
154. Firmicutes have a low G + C content in DNA
True
160. Bacillus sp. is a rod shaped microbe that divides only along 1 axis
True
166. The two commonly used methods to determine if a bacterium is motile are wet-mount preparation (microscopic) and motility media (mac-roscopic)
True
168. 0.005% triphenyltetrazolium chloride (TTC) TTC can be utilized by bacteria as an electron acceptor and in its reduced form turns red.
True
169. The purpose of making a smear is to adhere/fix the bacteria to the slide to prevent the sample from being lost during the staining process. When using a liquid culture, one loopful of culture is smeared onto a glass slide and allowed to air dry. The cells in the dried smear are then "fixed" to the slide by briefly heating. This process is known as heat fixation.
True
171. Bacteria have rigid cell walls that function to maintain a constant shape.
True
173. The most common clinically used methods of differential staining are the Gram stain and the Acid-fast stain.
True
175. Old cultures tend to decolorize more easily than younger cultures.
True
176. The acid fast stain receives its name because certain bacteria, particularly the Mycobacteria, have a tendency to resist decolorization by acids.
True
178. Acid fast organisms have a high content of fat or lipid and mycolic acids in their cell walls.
True
179. Two types of acid fast stains include Ziehl-Neelsen (Z-N) and Method Kinyon Method
True
182. Ethanol is thought to extract the lipid from the gram-negative cell wall and dehydrate the cell wall of the gram-positive organism
True
19. Contents of tubes will spill if you lay the tube on the table or invert it
True
20. Hold the tube in your nondominant hand (right-handed people should hold the tube in their left hand) and the inoculating loop in your dominant hand.
True
23. When handling a petri dish with agar tilt the lid up to open it, do not completely remove it
True
24. Airborne microorganisms can contaminate sterile media and inoculating tools
True
29. Cultural characteristics include size, form, margin, elevation, opacity, color
True
30. One of the most important steps in identifying a new bacteria or one isolated from a patient's specimen is noting colony morphology
True
31. Colony morphology is described as how the colony or clone of cells looks on the agar surface.
True
34. Nutrients present in various media or incubation conditions may contribute to altered colony size or appearance.
True
35. Increased or specific carbohydrate content may result in more pronounced bacterial capsule synthesis, leading to very mucoid colonies.
True
42. Mycoplasmas can be opportunistic pathogens.
True
43. Mycoplasmas can pass through sterilizing filters, and do not stain with ordinary stains.
True
48. Rickettsiae are very small bacteria that can only grow and multiply intracellularly, as they are obligate parasites.
True
50. Rickettsiae must be grown in cell culture or intact animals.
True
52. Pathogenic Rickettsiae include the causative agents for typhus and Rocky Mountain spotted fever.
True
55. Chlamydiae must grow and multiply inside another cell; then they are released to infect new cells.
True
56. There are two species of Chlamydiae responsible for human disease: psittaci (parrot fever) and trachomatis (STD, trachoma, LGV).
True
57. Psittaci and trachomatis can only be studied in cultured cells or intact animals
True
61. There are different degrees of opacity.
True
64. Size distinctions to be made include pinpoint, small, medium, and large.
True
65. In colony morphology, 'margin' refers to what the edge of the colony looks like
True
69. To observe opacity, hold the plate obliquely to the overhead light or place the plate over the writing of your textbook/notebook/handout.
True
70. Transparent colonies allow all of the light to pass through them.
True
71. Translucent colonies allow most of the light to pass through them; some light is blocked.
True
73. If the bacteria produce an intracellular pigment that is retained by the cell, the colony becomes colored.
True
74. If the bacteria produce an extracellular pigment that is excreted by the cell, the medium becomes colored.
True
75. If the organisms are translucent, the colored media will show through the colonies, and the colonies will appear to have the same color as the media.
True
78. Special stains are available for characteristic surface or internal components as well as for other cell components to aid in the study of microbes.
True
79. The acid-fast stain is a differential stain for Mycobacterium and related bacteria.
True
80. Mycobacterium is a genus that includes the causative ages of leprosy and tuberculosis
True
81. It is useful clinically to have a stain for rapid identification of Mycobacterium in sputum or skin scrapings.
True
82. Mycobacterium are unusual in that the cell wall has a mixture of waxy lipids called mycolic acids, that prevent the bacterium from staining by simple and gram stains.
True
85. A stain that is cooked into the waxy cell wall, and cannot be removed with acidified alcohol is acid-fast.
True
86. Non acid fast bacterium and tissue background will lose the carbolfuchsin stain when washed with acid-alcohol, becoming colorless.
True
88. The genus Mycobacterium contains some pathogens and many saprophytic species, found in soil and water, and also on human skin and mucous membranes.
True
91. Acid-fast stain is important for quick diagnosis because some strains of Mycobacterium, such as M. leprae, cannot yet be grown in culture.
True
92. Capsules are found on some bacteria (and fungi)
True
93. Capsules may actually relate to pathogenicity in some strains, such as Streptococcus pneumoniae, Klebsiella pneumoniae, and Clostridium perfringens.
True
98. There are direct and indirect methods of staining capsules.
True
Aerosols created by splattering of cultures are caused by improper flaming and cooling of needles and loops before use.
True
All of the organisms we work with should be handled as if they are opportunistic
True
Everything going into the incubator must be labeled with name, microbial content and other data, using black marking tools.
True
Inoculation loops and needles are flamed before and after use
True
The mouth of test tubes and other culture vessels are to be flamed before use
True
True/False: All of the organisms we work with should be handled as if they are pathogenic
True
`96. In a negative stain technique, material such as India ink or Congo red is used to coat the slide but not penetrate the cell or capsule.
True
41. Mycoplasma are pleomorphic because they have no cell wall.
True. pleomorphic = no cell walls
97. A stain can be used to color the cells, and then the capsule is seen as a clear region surrounding the cells against the dark background.
True; a halo
Pathogenic
causes diseases
Malachite green stains
endospores
114. Vegetative cells are dormant
false
60. Both the media and the colonies may be colored if the bacteria produces an intracellular pigment and an extracellular pigment
false
172. There are five basic bacterial shapes: cocci, bacilli, rectangle, star and spiral.
false; 3: cocci, bacilli, and spiral
100. Flagella have a carbohydrate structure requiring a special staining technique
false; fine protein structure
94. Small capsules can protect the microbe from host defense mechanisms, especially phagocytosis.
false; large capsules
95. Capsules are often identified immunologically, but can also be visualized with a simple gram stain.
false; with a simple negative stain
Safarin stains
gram negative
Crystal violet stains
gram positive
Chlamydiae is gram
negative
methylene blue stains
non acid fast bacteria
Chlamydiae are motile or non-motile
non-motile
Mycloplasma causes
pneumonia, urogenital and other infections that are normally found in normal mucous membrane microflora
Axenic culture
pure culture made from only 1 single species
Gram negative has
small amount of peptidoglycan
148. Which phylums have one genera? A. Cyanobacteria B. Chlamydiae C. Anabaena D. None of the above E. A and B
E. A and B
Exercise 6.2 164. _____ is/are bacterial flagellar arrangements that are polar A. monotrichous B. amphitrichous C. lophotrichous D. peritrichous E. A, B, and C
E. A, B, and C
162. The smallest object you can possibly see (as a barely-visible dot under the oil-immersion lens) with a light microscope is about ____ A. 0.1 μm B. 0.4 μm C. 2 μm D. 0.2 μm E. 0.3 μm
D. 0.2 μm
47. Types of colony morphology elevation include A. Crateriform B. Umbonate C. Flat D. All of the above E. None of the above
D. All of the above
117. Why is a capsule stain useful in the lab? A. To identify bacterium with a flagella B. To identify bacterium with an endospore C. Because encapsulated bacteria cannot be stained D. To identify whether or not a bacterium has a capsule
D. To identify whether or not a bacterium has a capsule
77. Characteristic surface or internal components that are of value in identifying organisms include: A. Endospores B. Capsules C. Flagella D. All of the above E. None of the above
D. all of above
137. Gram-negative phyla include Proteobacteria B. Cyanobacteria C. Chlamydiae D. All of the above E. A and B
D.All of the above
174. What is true of gram negative organisms A. stain blue/purple B. have thick peptidoglycan C. do not have an outer membrane D. clear when decolorized E. none of the above
D.Clear when decolorized
Hierachy of Taxonomic Groups
Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species
