Gram Stain

Question 1

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

Answer 1

Differential Stains

Question 2

Three examples of differential stains are

Answer 2

Gram Stain, Endospore Stain and Acid Fast Stain

Question 3

Bacterial cell walls are composed of

Answer 3

Peptidoglycan

Question 4

Gram positive bacteria stain

Answer 4

Purple

Question 5

Gram negative bacteria stain

Answer 5

Pink

Question 6

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

Answer 6

Gram positive bacteria

Question 7

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

Answer 7

Gram negative bacteria

Question 8

How many layers do gram positive bacteria have within their envelope

Answer 8

2

Question 9

How many layers do gram negative bacteria have within their envelope

Answer 9

3

Question 10

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

Answer 10

Crystal violet, iodine, alcohol and safranin

Question 11

During a gram stain this dye serves as the primary stain

Answer 11

Crystal Violet

Question 12

During a gram stain this dye serves as the counterstain

Answer 12

Safranin

Question 13

During a gram stain this reagent serves as the decolorizer

Answer 13

Alcohol

Question 14

During a gram stain this reagent serves as the mordant

Answer 14

Iodine

Question 15

Over decolorizing can cause gram positive bacteria to stain which color

Answer 15

Pink

Question 16

Under decolorizing can cause gram negative bacteria to stain which color

Answer 16

Purple

Question 17

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

Answer 17

Pink

Question 18

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

Answer 18

Purple