How We See The Invisible World Ch.2 Test Questions & Answers - Microbiology 1st Edition Test Bank with Answer Key by Nina Parker by Nina Parker. DOCX document preview.
Chapter 2: How We See the Invisible World
= Correct answer
Multiple Choice
- Which term is used to refer to a wave’s rate of vibration?
A. amplitude
B. frequency
C. trough
D. wavelength
Difficulty: Easy
ASM Standard: N/A
- On the figure, which letter represents a refracted ray of light?
A. A
B. B
C. C
D. D
Difficulty: Easy
ASM Standard: N/A
- On the electromagnetic spectrum, which type of wave has the shortest wavelength?
A. cosmic ray
B. infrared ray
C. ultraviolet ray
D. visible light
Difficulty: Moderate
ASM Standard: N/A
- Dyes are often used during microscopy to increase which of the following?
A. contrast
B. magnification
C. motility
D. resolution
Difficulty: Easy
ASM Standard: 32
- Which of the following was the first to use the term “cells”?
A. Robert Hooke
B. Robert Koch
C. Carolus Linnaeus
D. Antonie van Leeuwenhoek
Difficulty: Easy
ASM Standard: N/A
- Which of the following is the typical magnification of an object viewed using a 10× ocular lens and a 100× objective lens on a brightfield microscope?
A. 1×
B. 10×
C. 100×
D. 1000×
Difficulty: Moderate
ASM Standard: 32
- Most modern microscopes have two eyepieces, meaning that they are which of the following?
A. binocular
B. monocular
C. oil immersion
D. trinocular
Difficulty: Easy
ASM Standard: 32
- An annular stop is used for which type of microscopy?
A. confocal
B. darkfield
C. fluorescence
D. phase contrast
Difficulty: Easy
ASM Standard: 32
- Which of the following is the specific name for a stain that colors the background but not the specimen?
A. acid-fast stain
B. counterstain
C. differential stain
D. negative stain
Difficulty: Easy
ASM Standard: 32
- Which type of microscopy would work best for viewing internal cell structures?
A. atomic force microscopy
B. scanning electron microscopy
C. scanning tunneling microscopy
D. transmission electron microscopy
Difficulty: Moderate
ASM Standard: 32
- The Gram-staining procedure is best described as which of the following?
A. complex staining
B. differential staining
C. negative staining
D. simple staining
Difficulty: Easy
ASM Standard: 32
- When there is a substantial difference in refractive index between two materials, which of the following describes what will happen to light passing from one material to the other?
A. It will fail to be refracted.
B. It will undergo a large amount of refraction.
C. It will undergo a small amount of refraction.
D. It will undergo a variable amount of refraction.
Difficulty: Moderate
ASM Standard: N/A
- In microscopy, the focal length refers to which of the following?
A. a description of the wavelength needed for an image to be in focus
B. a measure of the amount of refraction produced by a lens
C. a measure of the thickness of the lens needed for an image to be in focus
D. the distance to the image point (at which all light entering a lens is parallel)
Difficulty: Moderate
ASM Standard: 32
- Which of the following are pigments used in microscopy to absorb and reflect light?
A. chromatographs
B. chromophores
C. oilophores
D. photophores
Difficulty: Easy
ASM Standard: N/A
- Negative staining is the standard approach used to visualize which structure(s)?
A. capsules
B. endospores
C. flagella
D. nucleoid regions
Difficulty: Moderate
ASM Standard: 6, 32
- Which is a standard mordant used in flagella staining?
A. basic fuchsin
B. iodine
C. safranin
D. tannic acid
Difficulty: Moderate
ASM Standard: 6, 32
- Which of the following pairs are common acid-fast staining techniques?
A. Gram and Kinyoun
B. negative and Schaeffer-Fulton
C. Ziehl-Neelsen and Kinyoun
D. Ziehl-Neelsen and Schaeffer-Fulton
Difficulty: Moderate
ASM Standard: 32
- Which is the primary stain used in the Ziehl-Neelsen technique?
A. acid-alcohol
B. carbolfuchsin
C. crystal violet
D. methylene blue
Difficulty: Moderate
ASM Standard: 32
- Which is the correct order of steps in Gram staining?
A. crystal violet stain, ethanol decolorization, Gram’s iodine mordant, safranin counterstain
B. crystal violet stain, Gram’s iodine mordant, ethanol decolorization, safranin counterstain
C. ethanol stain, crystal violet rinse, safranin counterstain, Gram’s iodine mordant
D. safranin stain, Gram’s iodine mordant, ethanol decolorization, crystal violet counterstain
Difficulty: Easy
ASM Standard: 32
- It is important to fix bacterial smears on a slide for which of the following reasons?
A. to attach them to the slide
B. to cause swelling of the cell to make interior structures more visible
C. to enhance the uptake of stains
D. to provide a nutrient medium to sustain the bacteria
Difficulty: Easy
ASM Standard: 32
- Which of the following is not commonly used for chemical fixation?
A. acetic acid
B. ethanol
C. glutaraldehyde
D. iodine
Difficulty: Moderate
ASM Standard: 32
- Which of the following is not involved in preparing a bacterial slide for Gram staining?
A. allowing the sample to dry on the slide
B. fixing the specimen to the slide
C. placing a smear on the slide
D. preparing a wet mount
Difficulty: Moderate
ASM Standard: 32
- Which of the following most specifically refers to stains with positively charged chromophores?
A. acid-fast dyes
B. acidic dyes
C. basic dyes
D. positive dyes
Difficulty: Moderate
ASM Standard: 32
- Which of the following most specifically refers to a stain that dyes a specimen rather than the background?
A. counterstain
B. mordant
C. negative stain
D. positive stain
Difficulty: Moderate
ASM Standard: 32
- Which of the following describes the difference between the Ziehl-Neelsen and Kinyoun acid-fast staining techniques?
A. The Ziehl-Neelsen technique uses a counterstain and the Kinyoun technique does not.
B. The Ziehl-Neelsen technique uses an acidic dye and the Kinyoun technique does not.
C. The Ziehl-Neelsen technique uses heat and the Kinyoun technique does not.
D. The Ziehl-Neelsen technique uses two dyes and the Kinyoun technique does not.
Difficulty: Moderate
ASM Standard: 32
- Which of the following described the difference between gram-positive and gram-negative cells that causes them to stain differently after Gram staining?
A. Gram-positive cells have a mycolic acid layer in their cell walls that holds in stain, whereas gram-negative cells lack this layer.
B. Gram-positive cells have capsules and gram-negative cells have S layers.
C. Gram-positive cells have thicker cell membranes than gram-negative cells.
D. Gram-positive cells have thicker peptidoglycan layers in their cell walls than do gram-negative cells.
Difficulty: Moderate
ASM Standard: 7, 32, 34, 36
- Which of the following would not potentially cause a gram-positive cell to appear gram-negative after Gram staining?
A. counterstaining with crystal violet instead of safranin
B. exposing the cells to ethanol for too long
C. using older bacterial cultures
D. using safranin as a primary stain
Difficulty: Moderate
ASM Standard: 32, 34, 36
- Which of the following does not cause the probe to move up and down above the specimen in atomic force microscopy?
A. chemical bonding
B. electrostatic forces
C. van der Waals forces
D. variations in current
Difficulty: Difficult
ASM Standard: 32
- Quantum tunneling of electrons is important in the mechanism underlying which microscope type?
A. AFM
B. SEM
C. STM
D. TEM
Difficulty: Moderate
ASM Standard: 32
- Which of the following is the chemical in some bacterial cells’ walls that makes them resist decolorization after acid-fast staining?
A. acetic acid
B. mycolic acid
C. peptidoglycan
D. phospholipid
Difficulty: Moderate
ASM Standard: 32
- Gram staining is useful for bacterial identification. Which of the following is another way it is most useful?
A. Knowing Gram staining results allows a researcher to know which organisms a bacterium can infect.
B. Knowing Gram staining results allows a researcher to select the appropriate growth medium for optimal bacterial growth.
C. Knowing Gram staining results is helpful in choosing an effective antibiotic.
D. Knowing Gram staining results is helpful in understanding a bacterium’s metabolic requirements.
Difficulty: Difficult
ASM Standard: 7, 23
- Which of the following is not true regarding capsule staining?
A. Capsules are typically stained using basic dyes.
B. Capsule staining does not require heat fixation in advance.
C. Capsule staining requires careful selection of a stain that can stain the capsule itself.
D. Capsule staining typically involves negative staining.
Difficulty: Difficult
ASM Standard: 7, 23
- Because endospores are difficult to stain, which of the following is generally needed?
A. Heat must be used to make the endospore take up stain.
B. Mycolic acid must be added to encourage the endospore to take up stain.
C. Negative staining must be used to stain endospores because they do not absorb stain.
D. The cells must be cooled to make the endospore more brittle prior to staining.
Difficulty: Difficult
ASM Standard: 7, 32
- When endospores are stained using the Schaeffer-Fulton method, which of the following correctly describes how they appear after staining?
A. The endospore appears green within a pink cell, because only the endospore retained the primary stain.
B. The entire cell appears green because the endospore surrounds all the vegetative material.
B. The entire cell appears pink because the endospore surrounds all the vegetative material.
C. The entire cell appears pink except for a clear area representing the endospore.
Difficulty: Moderate
ASM Standard: 6, 7, 32
- Specimens for TEM are prepared by doing which of the following?
A. dehydrating the specimen in ethanol and then coating it in a material that will repel electrons
B. sputter coating with a substance such as gold to repel electrons
C. using an ultramicrotome to cut very thin sections from samples embedded in plastic resin
D. using chemical fixation, followed by standard staining techniques such as the Gram stain
Difficulty: Difficult
ASM Standard: 32
True/False
- In fluorescence, emitted photons have the same amount of energy as absorbed photons.
Difficulty: Easy
ASM Standard: N/A
- A microscope with very high magnification and low resolution would allow you to clearly see small structures.
Difficulty: Easy
ASM Standard: 6
- The difference between a simple microscope and a compound microscope is that the latter only has one lens.
Difficulty: Easy
ASM Standard: N/A
- Flagella staining is very useful for diagnostic purposes in medical settings.
Difficulty: Moderate
ASM Standard: 7, 32
- The transmission electron microscope and scanning electron microscope produce very similar images, but the former can be show three-dimensional external structures.
Difficulty: Moderate
ASM Standard: 6, 32
- Differential interference contrast microscopy produces three-dimensional images of specimens.
Difficulty: Moderate
ASM Standard: 32
- During specimen preparation for transmission electron microscopy, the specimens are dehydrated in alcohol and embedded in plastic resin.
Difficulty: Difficult
ASM Standard: 32
- In atomic force microscopy, the movement of the probe tip is determined using Hooke’s law of elasticity.
Difficulty: Difficult
ASM Standard: 32
Matching
- Match each term with the best definition.
A. amplitude | i. electromagnetic radiation within certain parameters |
B. frequency | ii. the height of a wave peak or depth of a wave trough |
C. visible light | iii. the rate of vibration of a wave |
D. wavelength | iv. the distance between two wave peaks |
Answers: A. ii., B. iii., C. i., D. iv.
Difficulty: Easy
ASM Standard: N/A
- Match each term with the best definition.
A. absorbance | i. Light waves change direction when they enter a new medium. |
B. diffraction | ii. Two waves interact. |
C. interference | iii. A wave travels through something. |
D. refraction | iv. A material captures light energy. |
E. transmission | v. Light bends or scatters as it interacts with objects or openings. |
Answers: A. iv., B. v., C. ii., D. i., E. iii.
Difficulty: Moderate
ASM Standard: N/A
- Match each type of microscope with a common use for that microscope type.
A. brightfield | i. commonly used clinically; helpful in distinguishing living from dead cells, finding molecules within a cell, and for immunostaining |
B. darkfield | ii. widely used and easily available; used for examining common protists, bacteria, and tissues; stains are often needed |
C. fluorescence | iii. uses an annular stop, refraction, and interference to produce relatively high-resolution images without stains |
D. phase contrast | iv. used to examine an image produced with light that hits a specimen indirectly owing to the use of an opaque light stop; often used to view living microorganisms without stains |
E. two-photon | v. often used to penetrate thick specimens, such as biofilms, with long-wavelength light |
Answers: A. ii., B. iv., C. i., D. iii., E. v.
Difficulty: Difficult
ASM Standard: 32
- Match each type of microscopy with the best description.
A. atomic force microscopy | i. measures changes in current as a probe is moved at a constant height over a specimen |
B. scanning electron microscopy | ii. measures variations in the height of a probe moving over the specimen; height variations occur to maintain a constant current |
C. scanning tunneling microscopy | iii. yields images from electrons produced by an electron beam hitting the surface of a sputter-coated specimen |
D. transmission electron microscopy | iv. produces images from electrons that pass through a very thin specimen, allowing internal structures to be visualized |
Answers: A. ii., B. iii., C. i., D. iv.
Difficulty: Moderate
ASM Standard: 32
- Match the staining procedure with the chemicals used.
A. acid-fast stain | i. crystal violet, iodine, ethanol, safranin |
B. capsule stain | ii. tannic acid or potassium alum, pararosaniline or basic fuchsin |
C. endospore stain | iii. carbolfuchsin, acid alcohol, and methylene blue |
D. flagella stain | iv. malachite green, safranin |
E. Gram stain | v. India ink or nigrosin, sometimes with positive staining |
Answers: A. iii., B. v., C. iv., D. ii., E. i.
Difficulty: Moderate
ASM Standard: 32
- The choices describe possible scenarios and outcomes from Gram staining with standard stains (e.g., crystal violet and safranin). Match the scenario with the most likely outcome.
A. A gram-negative cell is stained, but the ethanol step is skipped. | i. The cell will probably appear pink, which will not correctly indicate its cell wall structure. |
B. A gram-positive cell with a severely damaged cell wall is stained. | ii. The cell will appear pink. |
C. A healthy gram-negative cell is stained. | iii. The cell will appear purple/violet. |
D. A healthy gram-positive cell is stained. | iv. The cell will probably appear purple/violet, which will not correctly indicate its cell wall structure. |
Answers: A. iv., B. i., C. ii., D. iii.
Difficulty: Difficult
ASM Standard: 6, 32
Fill in the Blank
- Compared with air, water has a(n) ________ refractive index.
Difficulty: Easy
ASM Standard: N/A
- The ________ electron microscope produces high-resolution images of three-dimensional surface structures of sputter-coated specimens.
Difficulty: Moderate
ASM Standard: 32
- Robert Hooke published ________, in which he described his observations of cork via compound microscopes.
Difficulty: Easy
ASM Standard: N/A
- ________ microscopy uses an opaque stop, is useful for viewing living organisms without using stains, and produces images with a dark background.
Difficulty: Moderate
ASM Standard: 32
- Acid-fast bacteria have ________ in their cell walls that retain carbolfuschin stain.
Difficulty: Moderate
ASM Standard: 6, 7, 32
- In acid-fast staining, cells that are not acid-fast usually appear ________.
Difficulty: Moderate
ASM Standard: 32
- During preparation of specimens for scanning electron microscopy, specimens are often sputter coated with ________ or a similar material.
Difficulty: Moderate
ASM Standard: 32
- Negative staining of capsules is commonly done using India ink or ________.
Difficulty: Moderate
ASM Standard: 6 32
- An acid-fast staining technique similar to the Ziehl-Neelsen technique is called the ________ technique.
Difficulty: Moderate
ASM Standard: 32
- When an object is relatively small relative to a wavelength of light, diffraction is ________ than if an object is relatively large.
Difficulty: Difficult
ASM Standard: 32
Short Answer
- Why is the resolution of a microscope image important?
Sample
Difficulty: Easy
ASM Standard: 32
- Who is believed to have developed the first microscopes that allowed microbes to be viewed?
Sample
Difficulty: Easy
ASM Standard: N/A
- What is the name of the lens that focuses light from a microscope light source onto the specimen on the stage?
Sample
Difficulty: Easy
ASM Standard: N/A
- Would you use immersion oil at high magnification or low magnification?
Sample
Difficulty: Easy
ASM Standard: 32
- What is the difference between fluorescence and phosphorescence?
Sample
Difficulty: Difficult
ASM Standard: N/A
- Which lens will produce an image with greater resolution: one with a higher numerical aperture or one with a lower numerical aperture? Why?
Sample
Difficulty: Moderate
ASM Standard: 32
- How does immersion oil improve the resolution of a microscope image?
Sample
Difficulty: Moderate
ASM Standard: N/A
- For what type of microscopy is an opaque light stop used, and what is its function?
Sample
Difficulty: Moderate
ASM Standard: N/A
- Why is it sometimes advantageous to avoid using stains when viewing microorganisms?
Sample
Difficulty: Moderate
ASM Standard: N/A
- What is another name for differential interference contrast microscopy?
Sample
Difficulty: Moderate
ASM Standard: N/A
- What are some common fluorochromes used in fluorescence microscopy?
Sample
Difficulty: Moderate
ASM Standard: 32
- In immunofluorescence, what are secondary antibodies used for?
Sample
Difficulty: Moderate
ASM Standard: 32
- Why is it important to embed specimens in plastic resin during their preparation for TEM?
Sample
Difficulty: Difficult
ASM Standard: 32
- Why can electron microscopes achieve higher resolutions than light microscopes?
Sample
Difficulty: Difficult
ASM Standard: 32
- Why do microscopes have rheostats? What is adjusted by adjusting a microscope’s rheostat?
Sample
Difficulty: Difficult
ASM Standard: 32
Brief Essay
Essay Question Rubric
RATING | Failing | Below Average | Competent | Advanced |
Criteria for evaluation | Answer does not provide an argument. Answer contains inaccuracies. Writing is poor and contains numerous grammatical mistakes and misspellings. | Answer fails to provide examples to support an argument. Writing is poor and grammatical errors are common. Answer is somewhat incoherent. | Answer provides an argument with one or two examples that support it. Writing is acceptable for the college level but may contain one or two grammatical mistakes or misspellings. | Answer clearly provides an argument with two or more excellent examples that support it; student makes the argument clearly and eloquently. Answer is well organized and free of grammatical errors and misspellings. |
POINT VALUE | 0 | 1 | 2 | 3 |
Assume rating/grading scale for the question ranges from 0 to 3 points.
- Explain how direct and indirect immunofluorescence assays differ, including an explanation of why indirect immunofluorescence is more commonly used.
Difficulty: Moderate
ASM Standard: 32, 36
- You prepare a slide of a bacterial sample by placing bacteria on a slide and examining it under a brightfield microscope. However, it is difficult to see the bacteria because the contrast is low. What are at least two ways you could increase the contrast?
Difficulty: Moderate
ASM Standard: 32
- Explain some advantages of two-photon microscopy, and explain why this type of microscopy is not more commonly used.
Difficulty: Moderate
ASM Standard: 32
- There is some debate over who invented the microscope. Explain why this debate exists and what factors help some individuals get more credit for their roles than others.
Difficulty: Difficult
ASM Standard: 31
- Many microbes live in biofilm communities and understanding these communities is important for a variety of reasons. For example, understanding biofilm formation within wounds and medical devices is important for improving patient outcomes. What are ways that light microscopy, confocal microscopy, fluorescence microscopy, electron microscopy, and two-photon microscopy can be used to study biofilms?
Difficulty: Difficult
ASM Standard: 32
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Microbiology 1st Edition Test Bank with Answer Key by Nina Parker
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