Lab 3 Exam
Decolorizer for Gram Stain
Ethanol
In the Spore staining, what is the mordant in this procedure? 1. Acid 2. Heat 3. Iodine 4. Phenol
Heat
Mordant for Gram Stain
Iodine
When doing a gram stain procedure, what color is a gram-negative cell after decolorizer has been added? 1. It will be a dark purple color 2. It will be a pink color 3. The Gram-negative cell is always pink 4. It will have no color
It will have no color
Primary Stain for Endospore Stain
Malachite Green
Counterstain for Acid Fast Stain
Methylene Blue
The Acid Fast Stain was developed to stain this specific genus (taxonomic group):
Myobacterium
Mordant for Acid Fast Stain
Phenol or steam
Counterstain for Endospore Stain
Safranin
Counterstain for Gram Stain
Safranin
When you look at this stained slide (green and red), what type of staining is this? 1. Capsule Stain 2. Acid Fast Stain 3. Spore Stain
Spore Stain
Mordant for Endospore Stain
Steam
You are Gram staining a known sample that contains BOTH gram-positive and gram-negative bacteria. After you complete the staining, you observe the following. Which of the following statements would apply to the image you see? 1. This image could be explained by omission of the Gram's iodine step, causing all cells to appear gram-negative 2. This image could be explained by leaving safranin dye on the smear for too long, causing all cells to wash out the purple color 3. This image could be explained by leaving the primary step on the smear for too long, causing all cells to absorb the red color 4. This image could be explained by omission of the decolorizing step, leading all cells to appear gram-negative
This image could be explained by omission of the Gram's iodine step, causing all cells to appear gram-negative
From this stained slide (green and red), what diseases might be associated with this slide? 1. This may show Anthrax or Tetanus 2. This will tell us Tetanus 3. This may show Tuberculosis
This may show Anthrax or Tetanus
When you look at this stained slide (blue and pink), what diseases might be associated with this slide? 1. This may show Anthrax or Tetanus 2. This may show us TB or Leprosy 3. This will tell us only Tuberculosis
This may show us TB or Leprosy
This is how your smear preparation looks in the microscope after simple staining with methylene blue. True or False: This image, as it appears, is able to be interpreted for information about the organism(s) on the slide.
True
Creating a bacterial smear from solid media, such as an agar plate or slant, often feels more tangible than creating a smear from liquid media. Which of the following is appropriate when creating a smear in this fashion? 1. You can place a big lump of bacterial sample onto the slide to ensure the smear is as concentrated as possible 2. Using the loop, you should disperse the bacterial sample material into a water drop on the slide 3. The tip of a gloved finger can be used to mix the bacteria and water on the surface of the slide
Using the loop, you should disperse the bacterial sample material into a water drop on the slide
Decolorizer for Endospore Stain
Water
When staining a known acid fast organism, in the presence of acid alcohol decolorizer, carbolfuchoin dye should _____ in the sampled bacteria. 1. change color 2. be neutralized 3. be removed 4. be retained
be retained
The primary stain, carbolfuchsin, binds to _____ in the sampled bacteria 1. peptidoglycan 2. membrane proteins 3. cell wall lipids, such as mycolic acid 4. carbohydrates
cell wall lipids, such as mycolic acid
If methylene blue was omitted from the acid-fast staining procedure, non-acid-fast cells would be ______ at the end of the staining process. Fill in the blanks. 1. purple 2. red 3. blue 4. clear
clear
Capsule staining is different from other classic microbiology staining protocols because. Select all that apply. 1. Capsule staining is a negative-staining protocol, compared to many other staining protocols that are positive staining 2. Capsules are specialized microorganism structures and require different techniques to visualize 3. Capsule staining only uses one dye as compared to all staining protocols where two or more dyes are used 4. Capsule staining does not use heat fixation, as other staining protocols do, to preserve capsule structure
1, 2, and 4 are correct
Which of the following is/are correct regarding acid-fast staining? Select all that apply. 1. The acid-fast staining procedure would be categorized as a differential stain 2. The correct order of an acid-fast stain is primary staining, decolorizing, counterstaining 3. The correct order of an acid-fast stain is primary staining, iodine fixation, decolorizing, counterstaining 4. The acid-fast staining procedure would be categorized as a simple stain
1 and 2 are correct
You can complete a capsule stain with the following results. Which of the following is/are correct regarding your stain? Select all that apply. 1. Capsules are visible 2. Counterstaining with crystal violet was likely omitted 3. Unnecessary heat fixing was performing 4. Nigrosin staining was likely omitted
1 and 2 are correct
What is the purpose of adding a strip of paper to the spore stain procedure? Select all that apply. 1. The paper keeps the dye from evaporating too quickly during the heating step 2. The paper is sticky and removes live bacteria from the smear 3. The paper allows for more contract time between the dye and spores 4. The paper is protective to the scientist doing the stain 5. The paper helps hold stain away from the sample
1 and 3 are correct
You have just performed on acid-fast staining and gotten the following result. Which of the following might explain this result? Select all that apply. 1. The sample contains only acid-fast bacteria 2. The mordant (fixative) step was performed incorrectly 3. The decolorization step was omitted 4. The counterstain step was performed for too long
1 and 3 are correct
Your acid fast stain is complete and correct. Which of the following statements would apply to the image you see? Select all that apply. 1. You can observe non-acid-fast bacterial cells on this field 2. You can observe acid-neutral bacterial on this field 3. You can observe acid-fast bacterial cells on this field 4. You cannot distinguish any bacteria on this field
1 and 3 are correct
Your Gram stain is complete and correct. Which of the following statements would apply to the image you see? Select all that apply. 1. You can observe gram-negative bacilli on this field 2. You can observe gram-neutral bacteria on this field 3. You cannot distinguish any bacteria on this field 4. You can observe gram-positive cocci on this field
1 and 4 are correct
Now that you have seen the difference in the smear preparation after simply methylene blue staining, which of the following is correct regarding your smear now? Select all that apply. 1. The addition of methylene blue makes visualizing some bacterial cell characteristics more apparent, compared to no staining 2. The addition of methylene blue helps visualize the shape and arrangements of bacterial cells that were difficult to discern without stain 3. Addition of methylene blue highlights the bacterial cell nucleus and organelles that were difficult to discern without stain 4. The addition of methylene blue helps show the intact appearance and localization of the cells, compared with no staining
1, 2, and 4 are correct
Based on what you understood from the video, which of the following statements are correct? Select all that apply. 1. In this image, the endospores are green in color 2. This image shows primarily endospores 3. This image shows primarily exospores 4. In this image, the endospores are red in color 5. This image could be representative of a Bacillus species 6. This image could be representative of a Staphylococcus species
1, 2, and 5 are correct
Why is aseptic technique important during laboratory activities like smear preparation? Select all that apply. 1. Proper aseptic technique helps prevent contamination from being introduced into your sample during preparation 2. Aseptic technique aids in selecting a treatment, because we can observe what methods kill the infectious sample 3. Aseptic technique helps prevent accidental infection of the handler 4. Proper aseptic technique aids in keeping microbes from spreading to other surfaces, where they might be contacted by others in the lab
1, 3, and 4 are correct
You have just performed an acid-fast staining and gotten the following result. Which of the following might explain this result? Select all that apply. 1. The bacteria are non-acid-fast 2. The heating temperature of the primary dye was incorrect 3. The carbolfuchsin was omitted 4. The acid alcohol step was performed for too long
1, 3, and 4 are correct
Your capsule stain is complete and correct. Which of the following statements would apply to the image you see? Select all that apply. 1. The bacterial cells are stained with crystal violet 2. The capsules have stained with the primary and secondary dye colors 3. No bacterial capsules can be visualized in this field 4. The background is stained dark with nigrosin 5. You can observe encapsulated organisms in this field
1, 4, and 5 are correct
You are Gram staining a known sample that contains BOTH gram-positive and gram-negative bacteria. After you complete the staining, you realize that you did not use the alcohol bottle at all. Which cells would appear purple? Select all that apply. 1. No cells would show purple color 2. Gram-positive cells 3. Gram-negative cells
2 and 3 are correct
As you create your smear from a sample on solid media, it is important to use an appropriate amount of material and evenly disperse the organisms onto the surface of the slide. Which of the following can occur due to using excessive material as you create a smear preparation. Select all that apply. 1. It will be difficult to sterilize the slide after the procedure is complete 2. It will be difficult to distinguish bacterial cell morphology and arrangements of cells on the smear sample 3. It will be difficult to remove excess dye stain in later steps of the smear procedure 4. It will be difficult to apply stain correctly to the slide for visualization
2, 3, and 4 are correct
This image depicts the results of a spore stain performed on a smear of a known spore-producing bacterial species. Which of the following could have led to the results shown here? Select all that apply. 1. The counterstain was not applied 2. The smear was performed correctly, but the culture conditions did not encourage spore formation 3. The malachite green step was skipped 4. The heat step was performed too long and killed all the spores 5. Too many organisms were used
2, 3, and 5 are correct
Based on what you understand from the video, which of the following statements is correct? Select all that apply. 1. This image shows a cell morphology of bacilli 2. This image shows a cell arrangement of streptococci 3. This image suggests the Gram stain was done incorrectly 4. This image shows a cell arrangement of staphylococci 5. This image shows a cell morphology of cocci 6. This image likely depicts a Gram-stained bacterial smear
2, 5, and 6 are correct
Your spore stain is complete and correct. Which of the following statements would apply to the image you see? Select all that apply. 1. You cannot distinguish any spores on this field 2. You cannot observe gram-positive and gram-negative bacteria on this field 3. You can observe vegetative bacteria on this field 4. You can observe spores on this field
3 and 4 are correct
Based on what you learned in this simulation, for which of the following samples would you skip the heat fixation step? 1. A sample of patient blood that you want to stain, looking for bacterial infection 2. A sample of patient sputum that you want to stain with heated carbol fushsin dye, looking for tuberculosis 3. A sample of pond water, looking for living bacterial activity such as observing for motility
A sample of pond water, looking for living bacterial activity such as observing for motility
Decolorizer for Acid Fast Stain
Acid Alcohol
When you look at this stained slide (blue and pink), what type of staining is this? 1. Spore Stain 2. Capsule Stain 3. Acid Fast Stain 4. Gram Stain
Acid Fast Stain
In the Acid Fast staining procedure, why does the methylene Blue not add to the cell's layers and create a purple color? 1. The pink, Carbol fuchsin entered the mycolic layer because of the mordant. Methylene Blue does not have the mordant in its stain 2. All of the options are correct 3. An Acid Fast cell (acid fast positive) will have a mycolic acid layer that keeps the Methylene Blue out of the layers 4. A Non-Acid Fast cell (acid fast negative) will have already lost the pink Carbol fuchsin
All of the options are correct
The endospore stain was developed to stain endospores produced by bacteria in the genera of:
Bacillus and Clostridium
What genus of bacteria can be identified by a spore stain procedure? 1. Staphylococcus 2. We won't be able to tell 3. Bacillus only 4. Bacillus or Clostridium
Bacillus or Clostridium
Looking at this diagram, what type of staining was done here? 1. Spore Stain 2. Capsule Stain 3. Acid Fast Stain 4. Gram Stain
Capsule Stain
What is the purpose of skipping the heat fixation step in the capsule stain procedure? 1. Heat fixation is unnecessary because organisms with capsules naturally adhere to the slide 2. Capsules are converted to slime layers if heated 3. Heat fixation is unnecessary in capsule staining because the organisms are harmless 4. Capsules will appear too dark if heated 5. Capsules are fragile and can be destroyed with heating
Capsules are fragile and can be destroyed with heating
Primary Stain for Acid Fast Stain
Carbolfuchsin
If we do a spore stain procedure and we see circular red cells, what do we know about these cells? 1. Circular cells will not make spores because they are not Bacillus or Clostridium 2. Circular cells will tell me that these may be Bacillus or Clostridium 3. These cells will not make spores 4. Circular red cells means that the spore lost their spore coat
Circular cells will not make spores because they are not Bacillus or Clostridium
If safranin was omitted from the spore stain, the vegetative bacterial cells would appear ______ in color. 1. Clear (colorless) 2. Purple 3. Red 4. Green
Clear (colorless)
Primary Stain for Gram Stain
Crystal violet
This is how your smear preparation looks in the microscope immediately after completion. True or False: This image, as it appears, is able to be interpreted for information about the organism(s) on the slide.
False
You are Gram staining a known sample that contains BOTH gram-positive and gram-negative bacteria. After you complete this staining, you realize that you did not perform the safranin step. Which of the following statements would correctly describe what you would see? 1. Gram-negative organisms might not be visible 2. You would not be able to view any organisms on the slide 3. Gram-positive organisms might incorrectly stain red 4. Gram-negative organisms might incorrectly stain purple
Gram-negative organisms might not be visible
You are Gram staining a known sample that contains BOTH gram-positive and gram-negative bacteria. After you complete the staining, you realize that you performed the decolorizer step for 10 minutes instead of 10 seconds! Which of the following statements would correctly describe what you would see? 1. Gram-negative organisms might incorrectly stain purple 2. You would not be able to view any organisms on the slide 3. All organisms would appear some shade of blue 4. Gram-positive organisms might incorrectly stain red
Gram-positive organisms might incorrectly stain red
In this diagram, why is the decolorizer not forcing the color from the cell? 1. The cell wall is too thick and has no porins to allow the larger CV-I complex out of the wall 2. The gram-negative cell wall is too thick to allow the bigger complex out of the wall 3. This is a more permeable, gram-negative cell, so the decolorizer will force the color to leave 4. The cell has a wall, outer-membrane and capsule that holds the CV-I complex in the layers
The cell wall is too thick and has no porins to allow the larger CV-I complex out of the wall
If we identify spores on a spore stain slide, what type of environment were the cells in before the spore stain procedure to see these results? 1. The environment is not a factor in this 2. The cells were in an unfavorable environment to create spores 3. The heat of the procedure caused the cells to make spores 4. The cells were in a favorable environment to create spores
The cells were in an unfavorable environment to create spores
This image shows the results of a spore stain performed on a known endospore-producing strain of bacteria. Which statement below would correctly explain this image? 1. The counterstain step was omitted 2. The water rinse steps washed out all dye in the spores 3. The heating step was not performed to allow dye to penetrate spore coats 4. The primary stain step was performed for too long
The heating step was not performed to allow dye to penetrate spore coats
You are observing streptococcus pneumoniae on a slide that has been stained using the capsular staining method. However, you do not see capsules surrounding the cells as you expected. What is a likely reason for this? 1. The slide was heat fixed, which can shrink or destroy capsules 2. The counterstain was not applied for enough time 3. Nigrosin was used to stain the background of the slide 4. The slide was over-washed with water, rinsing off capsules
The slide was heat fixed, which can shrink or destroy capsules
In the Spore staining, why does the spore not stain red like the cell? 1. The spore is too small to take on stain 2. All of the options are correct 3. The spore didn't have enough time to release the green to take on the red stain 4. The spore has many layers of protection that keep chemicals out
The spore has many layers of protection that keep chemicals out
From this diagram, what is the thick, yellow layer surrounding the cell? 1. The mycolic acid layer is under the capsule layer 2. The thick, yellow layer is the mycolic acid layer 3. The thick, yellow layer is the capsule of the cell 4. The thick, yellow layer is the cell wall of the cell
The thick, yellow layer is the mycolic acid layer
What do we know about the cells that stain pink in a Gram stain procedure? 1. We will know their cell wall is negative, we could also see shape and arrangement 2. Pink cells means that they are gram positive 3. Pink cells will be Staphylococcus 4. We will know their cell wall type only
We will know their cell wall is negative, we could also see shape and arrangement
The Capsule Stain procedure involves spreading a thin film of ________ across the slide
either nigrosine or india ink
The rationale for using methylene blue as a counterstain in the acid-fast protocol is to _____ 1. kill the remaining acid-fast bacterial cells 2. wash non-acid-fast bacterial cells off the slide 3. provide contrasting color to non-acid-fast bacterial cells 4. neutralize the acid alcohol staining reagent before handling
provide contrasting color to non-acid-fast bacterial cells
This image depicts a correctly performed acid-fast bacterial smear. Based on what you understand about the acid-fast staining process, acid-fast cells will appear ______, whereas non-acid-fast cells appear ______. 1. blue; red 2. as cocci; as bacilli 3. purple; pink 4. red; blue 5. pink; purple
red; blue
After correct Gram staining, the gram-negative cells will appear _____, whereas the gram-positive cells appear ____ 1. purple; red 2. red; purple 3. green; unstained 4. unstained; green 5. dark blue; light blue
red; purple
