MCB 2010L- LAB Test 1

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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


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