3-7/8 PL Quiz

Question 1

this is a differential stain in which a decolorization step occurs between the application of two basic stains

Answer 1

gram stain

Question 2

primary stain

Answer 2

crystal violet

Question 3

this is added second to enhance the crystal violet staining

Answer 3

mordant(iodine)

Question 4

this is the third and most critical step in the procedure

Answer 4

decolorization

Question 5

these cells are decolorized

Answer 5

gram negative cells

Question 6

what is colorized by the red counterstain, safranin

Answer 6

gram negative cells

Question 7

what color are the gram positive and why

Answer 7

purple because they are not decolorized and stay crystal violet

Question 8

the ability to resist decolorization or not is based on what

Answer 8

the different wall constructions of gram positive and gram negative cells

Question 9

what do gram negative cell walls contain

Answer 9

higher lipid content and thinner peptidoglycan layer

Question 10

what extracts the lipid and makes the gram negative cell wall more porus

Answer 10

the decolorizer

Question 11

why is the gram positive less susceptible to the decolorizer

Answer 11

it has thicker peptidoglycan and a greater degree of cross linking

Question 12

most variable results are a consequence of what

Answer 12

poor technique

Question 13

this happens by leaving the decolorizer on too long and get reddish positive cells

Answer 13

overdecolorize

Question 14

this happens when the gram negative cells are produced as purple

Answer 14

underdecolorizer

Question 15

what is another source of poor gram stain

Answer 15

inconsistency in preparation of the emulsion

Question 16

what is the size of a good emulsion

Answer 16

dime size

Question 17

what does the gram allow

Answer 17

determination of cell morphology, size and arrangement

Question 18

what is the basis for acid fast differential stains

Answer 18

the presence of mycolic acids in the cell walls of acid fast organisms

Question 19

this is a waxy substance that gives acid fast cells a higher affinity for the primary stain and resistance to decolonization by an acid alcohol solution

Answer 19

mycolic acid

Question 20

what are the two acid fast stain methods

Answer 20

ZN and K methods

Question 21

this method uses heat as part of the staining process

Answer 21

ZN method

Question 22

this method uses a cold stain

Answer 22

K method

Question 23

this repels typical aqueous stains

Answer 23

waxy wall of acid fast cells

Question 24

in the ZN method this is used as the primary stain because it is lipid soluble and penetrates the waxy cell

Answer 24

carbolfuchsin