Test 1-Quiz 4

Question 1

Purpose of the gram stain

Answer 1

differential procedure, uses 2 basic dyes and a decolorization step to differentiate between 2 classes of bacteria based on their cell wall composition

Question 2

Gram positive bacteria

• cell wall
• color when stained
• diseases caused

Answer 2

• thick layer of peptidoglycan
• Purple due to crystal violet
• scarlet fever, pneumonia, gas gangrene

Question 3

Gram negative bacteria

• cell wall
• color when stained
• diseases caused

Answer 3

• thin layer of peptidoglycan
• pink due to Safranin
• dysentry, typhoid fever, bubonic plague

Question 4

Basic Dye primary stain

Answer 4

Crystal Violet

Question 5

Mordant

Answer 5

Gram’s Iodine

Question 6

Decolorizing Agent

Answer 6

95% Ethanol or H20 (endospore stain)

Question 7

Counterstain (secondary stain)

Answer 7

Safranin O

Question 8

Crystal Violet soaks into the cell wall of

Answer 8

any bacteria present, gram positive or negative

Question 9

Gram’s Iodine is a ____ that ____ the dye to the cells

Answer 9

mordant, fixes

Question 10

95% Ethanol is used to

Answer 10

rinse the Gram’s Iodine off the slide.

Question 11

The gram ____ are decolorized due to the dissolution of the lipid layer in the cell wall and the thinner layer of peptidoglycan

Answer 11

negative

Question 12

The final process after the gram negative bacteria has been decolorized is to apply the secondary stain _______, which will cause that bacteria to turn pink

Answer 12

Safranin O

Question 13

The ___ is a differential staining technique used to detect the presence and location of spores in bacterial cells

Answer 13

endospore

Question 14

Characteristics of endospores (3)

Answer 14

• one cell can make one spore
• Resistant to heat, chemicals, radiation
• do not take up conventional dyes

Question 15

Purpose of the endospore

Answer 15

increases chance for survival

Question 16

Bacteria that produce endospores

Answer 16

Bacillus-anthrax

Clostridium-Tetanus, Botulism, Gas Gangrene

Question 17

_____ is a differential stain used to detect cells that are capable of retaining a primary stain when treated with acid alcohol.

Answer 17

Acid-Fast

Question 18

The main acid-fast organisms are members of the genus ______

Answer 18

Mycobacterium

Question 19

Characteristics of Mycobacterium (3)

Answer 19

• cell wall contains mycolic acid (waxy lipid) that causes bacterium to resist staining
• heat drives stain into cell walls and makes it resistant to decolorization
• leprosy and tuberculosis

Question 20

T or F: Mycobacterium produces endospores

Answer 20

False

Question 21

What is the primary stain used during the gram stain

Answer 21

Crystal Violet

Question 22

Microscope slides must be steamed over boiling water during which staining procedures

Answer 22

Acid Fast and Spore stains

Question 23

What genus is detected by performing acid-fast stain

Answer 23

Mycobacterium

Question 24

Gram negative is ___ and gram positive is ___

Answer 24

pink, purple

Question 25

What color was the acid fast organism following the acid fast stain

Answer 25

red

Question 26

_____ is used as a mordant during the gram stain

Answer 26

Gram’s iodine

Question 27

Which is used to stain bacterial endospores

Answer 27

Malachite Green