BIOS 280 Lab Quiz 2; Questions and Answers 100% Pass
the first step in the gram-stain process is to apply ____ stain to a heat-fixed bacterial smear;
the stain is then rinsed off with _____ Correct Ans-crystal violet
water
the second step in the gram-stain process is that the ____ solution is added to the slide; this
acts as a ____, which binds the crystal violet dye to the peptidoglycan layer in the cell wall
Correct Ans-iodine
mordant
the third step in the gram-stain process is that the bacterial smear is ____ with alcohol; any
dye not firmly fixed into the cell wall will wash out; then safranin, a ____, is applied to the
smear Correct Ans-decolorized
counterstain
gram-positive organisms will retain the crystal violet in their thick cell walls with the help of
the mordant and appear ____ Correct Ans-purple
,BIOS 280 Lab Quiz 2; Questions and Answers 100% Pass
the alcohol removes the purple stain from gram-negative organisms, and the colorless cells
take up the safranin counterstain, which appear ____ Correct Ans-pink
____-fixing prevents the bacteria from washing off the slide Correct Ans-heat
the first step in heat-fixing the bacteria is to place 1-2 loopfuls of distilled water on a slide; be
sure to use an ____ loop; aseptically transfer a small amount of bacterial culture from a plate;
mix the culture with the distilled water on a slide; spread the liquid evenly over the slide
Correct Ans-incinerated
the second step in heat-fixing the bacteria is to allow the slide to ____-dry; it is dry when
there is no visible moisture or wetness on the slide Correct Ans-air
the third step in heat-fixing the bacteria is to heat-fix the slide by either leaving the slide on
the slide warmer for ____ minutes, or holding the slide (with a clothespin) against the outside
of a turned-on incinerator for ____ minutes Correct Ans-10
1-1.5
after the slide is heat-fixed, the slide is ready for ____ Correct Ans-staining
, BIOS 280 Lab Quiz 2; Questions and Answers 100% Pass
the first step to perform a gram-stain is to place the slide on the staining rack over the sink;
you may use a clothespin to hold the slide; add 2-3 drops of ____ stain to the slide for about
30 seconds Correct Ans-crystal violet
the second step to perform a gram-stain is to rinse the slide with a small amount of distilled
____ Correct Ans-water
the third step to perform a gram-stain is to add 2-3 drops of Gram's ____ for 30 seconds; rinse
with distilled water Correct Ans-iodine
the fifth step to perform a gram-stain is to hold the slide at a 45 degree angle over the sink;
rinse with ____ until no more purple dye runs off; rinse with distilled water Correct Ans-
alcohol
the seventh step to perform a gram-stain is to add 2-3 drops of ____ for 30 seconds; rinse
with distilled water; carefully (gentle) blot the slide dry with ____ paper Correct Ans-
safranin
bibulous
the first step in the gram-stain process is to apply ____ stain to a heat-fixed bacterial smear;
the stain is then rinsed off with _____ Correct Ans-crystal violet
water
the second step in the gram-stain process is that the ____ solution is added to the slide; this
acts as a ____, which binds the crystal violet dye to the peptidoglycan layer in the cell wall
Correct Ans-iodine
mordant
the third step in the gram-stain process is that the bacterial smear is ____ with alcohol; any
dye not firmly fixed into the cell wall will wash out; then safranin, a ____, is applied to the
smear Correct Ans-decolorized
counterstain
gram-positive organisms will retain the crystal violet in their thick cell walls with the help of
the mordant and appear ____ Correct Ans-purple
,BIOS 280 Lab Quiz 2; Questions and Answers 100% Pass
the alcohol removes the purple stain from gram-negative organisms, and the colorless cells
take up the safranin counterstain, which appear ____ Correct Ans-pink
____-fixing prevents the bacteria from washing off the slide Correct Ans-heat
the first step in heat-fixing the bacteria is to place 1-2 loopfuls of distilled water on a slide; be
sure to use an ____ loop; aseptically transfer a small amount of bacterial culture from a plate;
mix the culture with the distilled water on a slide; spread the liquid evenly over the slide
Correct Ans-incinerated
the second step in heat-fixing the bacteria is to allow the slide to ____-dry; it is dry when
there is no visible moisture or wetness on the slide Correct Ans-air
the third step in heat-fixing the bacteria is to heat-fix the slide by either leaving the slide on
the slide warmer for ____ minutes, or holding the slide (with a clothespin) against the outside
of a turned-on incinerator for ____ minutes Correct Ans-10
1-1.5
after the slide is heat-fixed, the slide is ready for ____ Correct Ans-staining
, BIOS 280 Lab Quiz 2; Questions and Answers 100% Pass
the first step to perform a gram-stain is to place the slide on the staining rack over the sink;
you may use a clothespin to hold the slide; add 2-3 drops of ____ stain to the slide for about
30 seconds Correct Ans-crystal violet
the second step to perform a gram-stain is to rinse the slide with a small amount of distilled
____ Correct Ans-water
the third step to perform a gram-stain is to add 2-3 drops of Gram's ____ for 30 seconds; rinse
with distilled water Correct Ans-iodine
the fifth step to perform a gram-stain is to hold the slide at a 45 degree angle over the sink;
rinse with ____ until no more purple dye runs off; rinse with distilled water Correct Ans-
alcohol
the seventh step to perform a gram-stain is to add 2-3 drops of ____ for 30 seconds; rinse
with distilled water; carefully (gentle) blot the slide dry with ____ paper Correct Ans-
safranin
bibulous
