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Microbiology Chapter 4: Microscopy
Microscopy, Staining, and Classification
64
Microbiology
Undergraduate 2
03/03/2013

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Term
1 micrometer
Definition
1,000 nanometers is equal to which of the following?
Term
differential interference contrast microscopy
Definition
The three-dimensional effect observed in this micrograph is produced by ______________.
Term
condenser
Definition
Which part of the microscope shown here focuses light through the specimen?
Term
False

Mycobacterium tuberculosis, the cause of tuberculosis, is often demonstrated by the use of such stains as the acid-fast stain.
Definition
A patient suffering from tuberculosis could be diagnosed by the use of a negative stain.
Term
endospores
Definition
Acid-fast Mycobacteria are distinguished from non-acid fast bacteria by the presence of ____________________.
Term
scanning electron microscopy
Definition
A three-dimensional image of a bacterium is achieved by using ____________________.
Term
10X
Definition
Assume that you are looking at a 25 um plant cell magnified 100X. If you are using a 10X ocular lens, what is the magnifying power of the objective lens?
Term
True
Definition
Bacterial smears must be heat-fixed prior to staining procedures.
Term
Condenser
Definition
Which part of the microscope shown here focuses light through the specimen?
Term
False
Definition
A counterstain may be used to improve the bonding between a stain and the specimen.
Term
selectively remove stain from cells.
Definition
A decolorizer is used to:
Term
False.
Mycobacterium tuberculosis, the cause of tuberculosis, is often demonstrated by the use of such stains as the acid-fast stain.
Definition
A patient suffering from tuberculosis could be diagnosed by the use of a negative stain.
Term
False.
A scanning tunneling microscope is an example of a probe microscope.
Definition
A scanning tunneling microscope is an example of a light microscope.
Term
scanning electron microscopy.
Definition
A three-dimensional image of a bacterium is achieved by using ____________________.
Term
the phase plate.
Definition
All of the following are components of a bright-field compound microscope EXCEPT:
Term
The specimen must be sectioned prior to viewing.
Definition
All of the following are true for both TEM and SEM except:
Term
Atomic force
Definition
All of the following are types of light microscopy except:
Term
condenser
Definition
As light travels through a compound light microscope, what is the second structure through which it passes?
Term
10X
Definition
Assume that you are looking at a 25 um plant cell magnified 100X. If you are using a 10X ocular lens, what is the magnifying power of the objective lens?
Term
True
Definition
Bacterial smears must be heat-fixed prior to staining procedures.
Term
True
Heat or chemicals, such as methanol and formalin, are good fixation agents. Both of these types of agents help dry out cells and make them stick to a slide.
Definition
Endospore stains and acid-fast stains both involve heat.
Term
True
Definition
Fluorescent-labeled antibodies would allow specific recognition of one bacterium in a mixed culture of bacteria.
Term
True
Definition
Gram-positive bacteria retain the primary stain after decolorizing with alcohol.
Term
1000X
Definition
If you use a compound light microscope, a 2 um (micrometer) bacterial cell is best seen at which magnification?
Term
False
Definition
Immersion oil acts to decrease refraction of light rays and thus increase magnification.
Term
False
Immersion oil works by increasing the numerical aperture of a lens.
Definition
Immersion oil improves resolution because it decreases the working distance.
Term
False
The condenser lens, not the ocular lens, directs light through the specimen.
Definition
In a compound microscope, the lens that directs light through the specimen is the ocular lens.
Term
colorless.
Definition
In a negative stain, gram-negative bacteria will be:
Term
unstained in a colored background.
Definition
In a negative staining procedure, the bacterial cells would be ____________________.
Term
Answers A, B, and C are correct.
Definition
In microscopy, which of the following plays an important role in visualizing extremely small objects clearly?
Term
primary stain.
Definition
In the Gram stain, crystal violet is the ____________________.
Term
in thick layers of peptidoglycan.
Definition
In the Gram stain, crystal violet remains in gram-positive cells after treatment with alcohol because crystal violet-iodine (CV-I) complexes are trapped ____________________.
Term
purple
Definition
In the Gram stain, if the decolorizing step is deleted, gram-negative cells will appear ____at the completion of the staining procedure.
Term
counterstain
Definition
In the Gram stain, safranin serves as the ___________.
Term
ethanol/acetone
Definition
In the Gram stain, which of the reagents actually differentiates between Gram-positive and Gram-negative cells?
Term
presence of an endospore.
Definition
In the Gram-stain procedure, a clear oval in the center of a cell could indicate:
Term
clear halos
Definition
In the capsule stain using India ink, capsules are distinguished as _________surrounding cells.
Term
alcohol
Definition
In the decolorizing step of the Gram stain, which reagent is used?
Term
False
Definition
Magnification is the quality of the microscope that allows one to distinguish between two points that are very close together.
Term
False
Definition
Phase-contrast microscopy is an especially useful type of microscopy because it permits detailed examination of internal structures in living microorganisms.
Term
True
Definition
Phase-contrast microscopy is an especially useful type of microscopy because it permits detailed examination of internal structures in living microorganisms.
Term
3-1-4-5-2
Definition
Place the structures of the compound light microscope in the order that light passes through them on the way to the observer's eyes: (1) condenser, (2) ocular lens, (3) illuminator, (4) specimen, (5) objective lens.
Term
wavelength
Definition
Resolution is great when using an electron microscope because the _____________ of the electron beam is much less than that of visible light.
Term
False
Definition
Stains used in electron microscopy increase the contrast between specimen and background by colorizing the internal structures differently.
Term
False
Definition
The Gram stain is important in microbiology because it differentiates all pathogens from all nonpathogenic bacteria.
Term
2000x
Definition
The limit of useful magnification for a light microscope is _______________________.
Term
make gram-negative cells visible.
Definition
The purpose of the counterstain in the Gram stain is to:
Term
It attaches cells firmly to the slide's surface.
Definition
What is the purpose of fixation in smear preparation?
Term
Which is common to the Gram stain and acid-fast stain?
Definition
Fixation of the smear prior to staining.
Term
UV > Violet > Red
Definition
Which of the following has the shortest wavelength?
Term
electron microscope
Definition
Which of the following is not a modification of a compound microscope?
Term
Cell structures are differentiated
Definition
Which of the following is not accomplished by fixing cells to a slide?
Term
0.02 microm ribosome
Definition
Which of the following is not visible through a compound light microscope?
Term
1000 nm (length) mitochondrion
Definition
Which of the following is the same size as a 1 microm (length) bacterial cell?
Term
0.01 cm
Definition
Which of the following measurements does not equal 1mm?
Term
acid-fast stain
Definition
Which of the following stains is used for visualizing Mycobacterium?
Term
Probe microscope

Confocal, phase-contrast, and dark-field microscopes are all types of light microscopes. As such, they can magnify only up to about 2,000X.
Definition
Which of the following types of microscopes should be used to view a specimen at 50,000X?
Term
Phase-contrast
Definition
Which of the following types of microscopy is most useful for viewing the internal structures of unstained specimens?
Term
Brightfield.
Definition
Which type of light microscopy is used to visualize stained specimens?
Term
Atomic force
Definition
Which type of microscope uses a metal and diamond probe that is gently forced down along the surface of a specimen?
Term
Fluorescence microscopy
Definition
Which type of microscopy is used to identify pathogenic bacteria in clinical specimens?
Term
human cells and gram-positive bacteria.
Definition
You prepare a smear of tooth scrapings and see large (~10 microm) red nucleated cells and smaller (~2 microm) blue cells. You can conclude that you are seeing:
Term
there are bacteria on your teeth.
Definition
You see blue bacterial cells in a gram-stained smear from your tooth scrapings. You can conclude that:
Term
he didn't fix the smear.
Definition
Your lab partner tells you the bacteria are moving in his Gram stain. You can conclude that:
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