Lab 3.6: Gram stain

Question 1

Gram stain distinguishes what?

Answer 1

-gram negative and gram positive bacteria

Question 1

Who and when was gram stain created?

Answer 1

-1884
-Hans Christian Gram

Question 2

Gram negative

Answer 2

-thin peptidoglycan cell wall
-higher lipid content

Question 3

Gram positive

Answer 3

-thick peptidoglycan cell wall
-lower lipid content

Question 4

If the slide is not rinsed thoroughly or the stain
is allowed to dry on the slide, ?? of stain
precipitate may form and may be confused
with bacterial cells.

Answer 4

-spots

Question 5

?? from an old or improperly made stain solution can
disrupt the field or stain precipitate may be mistakenly identified
as bacteria

Answer 5

-stain crystals

Question 6

True or False:
The Gram stain uses a decolorization step after the application of two basic stains.

Answer 6

–false

Question 7

True or false:
The Gram this stain allows determination of cell morphology, size, and arrangement.

Answer 7

-true

Question 8

In the Gram stain, after staining with crystal violet, all cells will be ____________

Answer 8

-purple

Question 9

Upon completion of the Gram stain, Gram-positive cells will appear:

Answer 9

-purple

Question 10

In the Gram stain, the decolorizing agent is

Answer 10

-alcohol

Question 11

The Gram stain is a

Answer 11

-differential stain

Question 12

During a stain procedure, why is it necessary to heat fix the cells?

Answer 12

-to adhere them to the slide

Question 13

In the Gram stain, the primary stain is

Answer 13

-crystal violet

Question 14

What does iodine do?

Answer 14

-acts as a mordant to enhance crystal violet staining by forming a crystal violet iodine complex

Question 15

Gram negative cells can be colorized by the red counterstain ?? , but gram positive cells are already violet and cannot.

Answer 15

-safranin