Deck 6: Role of Microscopy

Question 1

The fourth step in the Gram stain is the application of the

A)safranin.
B)crystal violet.
C)Gram's iodine.
D)Gram's decolorizer.

Answer 1

A
Safranin is the third stain used in the Gram stain sequence.

Question 2

In the Kinyoun acid-fast staining method, ___________ replaces __________ in the primary stain solution.

A)increased phenol; heat
B)heat; increased phenol
C)mycolic acid; heat
D)carbolfuchsin; phenol

Answer 2

A
The Kinyoun method is one in which the heat step of the traditional acid-fast staining method is replaced by increased phenol.

Question 3

In microscopy, resolution can be defined as

A)the magnification power.
B)the extent to which detail in the magnified object is maintained.
C)the ability of objects to stand out from the background.
D)All of the above are correct.

Answer 3

B
The extent to which detail in the magnified object is maintained is called resolution.

Question 4

The fluorochrome stain that can be used to detect mycobacteria is

A)calcofluor white.
B)acridine orange.
C)auramine.
D)immunofluorescence.

Question 5

Of the different types of staining and microscopy techniques, which is basically the most sensitive?

A)Chromogenic
B)Fluorescent
C)Phase contrast
D)Light field

Question 6

The third step in the Gram stain is the application of the

A)safranin.
B)crystal violet.
C)Gram's iodine.
D)Gram's decolorizer.

Question 7

The first step in the Gram stain is the application of the primary stain

A)safranin.
B)crystal violet.
C)Gram's iodine.
D)Gram's decolorizer.

Question 8

After which step in the Gram stain are gram-positive bacteria FIRST distinguished from gram-negative?

A)Crystal violet
B)Iodine mordant
C)Gram's decolorizer
D)Safranin

Question 9

Magnifications in excess of 100,000´ are achieved by which type of microscopy?

A)Bright-field microscopy
B)Electron microscopy
C)Dark-field microscopy
D)Phase contrast microscopy
E)All of the above are correct.

Question 10

The second step in the Gram stain is the application of the

A)safranin.
B)crystal violet.
C)Gram's iodine.
D)Gram's decolorizer

Question 11

Contrast in microscopy is most commonly achieved by

A)changing objectives for various specimens.
B)increasing the resolution or resolving power.
C)staining techniques.
D)adding a blue filter to the light path.

Question 12

A mordant that is applied after the primary stain to chemically bond the alkaline dye to the bacterial cell wall is

A)safranin.
B)crystal violet.
C)Gram's iodine.
D)Gram's decolorizer.

Question 13

The fluorochrome stain that can be used to study fungus is

A)calcofluor white.
B)acridine orange.
C)auramine.
D)immunofluorescence.

Question 14

The acid-fast stain is specifically designed for bacteria whose cell walls contain

A)teichoic acids.
B)mycolic acids.
C)peptidoglycan.
D)disaccharide-pentapeptide subunits.

Question 15

Which of the following statements is true concerning dark-field microscopy?

A)This type of microscopy is used in some laboratories to detect spirochetes.
B)The condenser does not allow light to pass directly through the specimen but directs the light to hit the specimen at an oblique angle.
C)This technique involves the alteration of microscopic technique rather than the use of dyes or stains to achieve contrast.
D)All of the above are correct.