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Davis BIO 225 (Lab) > Gram Stain > Flashcards

Flashcards in Gram Stain Deck (18)
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1
Q

This staining procedure makes use of two or more dyes and distinguishes between two kinds of organisms or between two different parts of an organism

A

Differential Stains

2
Q

Three examples of differential stains are

A

Gram Stain, Endospore Stain and Acid Fast Stain

3
Q

Bacterial cell walls are composed of

A

Peptidoglycan

4
Q

Gram positive bacteria stain

A

Purple

5
Q

Gram negative bacteria stain

A

Pink

6
Q

These bacteria have a thick peptidoglycan layer and lack and outer cell membrane

A

Gram positive bacteria

7
Q

These bacteria have a thin peptidoglycan layer and have an outer cell membrane

A

Gram negative bacteria

8
Q

How many layers do gram positive bacteria have within their envelope

A

2

9
Q

How many layers do gram negative bacteria have within their envelope

A

3

10
Q

What is the correct order of reagents when performing a gram stain?

A

Crystal violet, iodine, alcohol and safranin

11
Q

During a gram stain this dye serves as the primary stain

A

Crystal Violet

12
Q

During a gram stain this dye serves as the counterstain

A

Safranin

13
Q

During a gram stain this reagent serves as the decolorizer

A

Alcohol

14
Q

During a gram stain this reagent serves as the mordant

A

Iodine

15
Q

Over decolorizing can cause gram positive bacteria to stain which color

A

Pink

16
Q

Under decolorizing can cause gram negative bacteria to stain which color

A

Purple

17
Q

Forgetting to use iodine during a gram stain can cause all the cells to turn which color

A

Pink

18
Q

Forgetting to use alcohol during a gram stain can cause all the cells to turn which color

A

Purple