FINAL LAB EXAM Appropriate
Questions And Responses
Gram stain: Is this culture pure or mixed? Appropriate Responses Pure if the stain
produces bacterium morphology that is consistent.
Mixed if there are gram negative and gram positive bacterium present and different
morphological arrangement.
What is the gram stain Appropriate Responses + = purple
- = red/pink
Gram: arrangements of bacterial cells? Appropriate Responses Diplo-cocci
streptococci
tetrad
sarcinae
staphylocci
single bacillus
diplobacillus
steptobacilli
coccbacillus spirilla
spirochete
vibrio
Steps of gram staining Appropriate Responses 1)Fix the smear
2)Apply the P.S -Crystal violet
3) wash
4) Apply the mordant- Iodine
5)wash
6) Apply the decolorizer- Acetone Alcohol
7) wash
8)Apply CS-Saftanin
9wash
10) blot dry
11) obeserve
Steps of acid fast & results Appropriate Responses Fix the smear
P.S- Carbol Fuchsin (5min)
Decolorizer- acid Alcohol
C.S- Methylene blue or Brilliant Green
+= Red
- = Blue
examples of Acid fast Appropriate Responses Mycobacterium
, Nocardia
capsule staining Appropriate Responses Negative staining
Drop P.S- Congo Red
Mix the smear
Air dry COMPLETELY
apply C.S - Maneval
+= clear zone
Examples of capsule staining Appropriate Responses Bacillus, Klebsiella,
Streptococcus
Endospore Stain Appropriate Responses 1)fix the smear
2)cover the smear with a piece of paper
3)under the stream apply P.S - Malachite Green
4) do not let dry completely
5) C.S = safranin
Examples of endospore stain Appropriate Responses Clostridium
Botulinum
Describe what you see in
Tryptophan Hydrolysis (Indole) = Appropriate Responses + = red ring
- = yellow ring
Media of Tryptophan Hydrolysis Appropriate Responses Typtophan broth
SIM
MIO
What is the purpose of the SIM medium test Appropriate Responses used for
detemination of 3 bacterial activities
1) sulfur reduction
2) indole production from tryptophan
3) motility
The reagent for Tryptophan hydrolysis Appropriate Responses Kovac's reagent
What is the name of the Black precipitate that forms in SIM deep tube? Appropriate
Responses Iron Sulfide or Ferrous Sulfide (FeS)
(the product of the reaction btw H2S & FeSO4)
What information will this provide about the inoculated bacterium? Appropriate
Responses It releases Hydrogen Sulfide (H2S) from the sulfur containing amino acid
cysteine or cystine, or methionine
Questions And Responses
Gram stain: Is this culture pure or mixed? Appropriate Responses Pure if the stain
produces bacterium morphology that is consistent.
Mixed if there are gram negative and gram positive bacterium present and different
morphological arrangement.
What is the gram stain Appropriate Responses + = purple
- = red/pink
Gram: arrangements of bacterial cells? Appropriate Responses Diplo-cocci
streptococci
tetrad
sarcinae
staphylocci
single bacillus
diplobacillus
steptobacilli
coccbacillus spirilla
spirochete
vibrio
Steps of gram staining Appropriate Responses 1)Fix the smear
2)Apply the P.S -Crystal violet
3) wash
4) Apply the mordant- Iodine
5)wash
6) Apply the decolorizer- Acetone Alcohol
7) wash
8)Apply CS-Saftanin
9wash
10) blot dry
11) obeserve
Steps of acid fast & results Appropriate Responses Fix the smear
P.S- Carbol Fuchsin (5min)
Decolorizer- acid Alcohol
C.S- Methylene blue or Brilliant Green
+= Red
- = Blue
examples of Acid fast Appropriate Responses Mycobacterium
, Nocardia
capsule staining Appropriate Responses Negative staining
Drop P.S- Congo Red
Mix the smear
Air dry COMPLETELY
apply C.S - Maneval
+= clear zone
Examples of capsule staining Appropriate Responses Bacillus, Klebsiella,
Streptococcus
Endospore Stain Appropriate Responses 1)fix the smear
2)cover the smear with a piece of paper
3)under the stream apply P.S - Malachite Green
4) do not let dry completely
5) C.S = safranin
Examples of endospore stain Appropriate Responses Clostridium
Botulinum
Describe what you see in
Tryptophan Hydrolysis (Indole) = Appropriate Responses + = red ring
- = yellow ring
Media of Tryptophan Hydrolysis Appropriate Responses Typtophan broth
SIM
MIO
What is the purpose of the SIM medium test Appropriate Responses used for
detemination of 3 bacterial activities
1) sulfur reduction
2) indole production from tryptophan
3) motility
The reagent for Tryptophan hydrolysis Appropriate Responses Kovac's reagent
What is the name of the Black precipitate that forms in SIM deep tube? Appropriate
Responses Iron Sulfide or Ferrous Sulfide (FeS)
(the product of the reaction btw H2S & FeSO4)
What information will this provide about the inoculated bacterium? Appropriate
Responses It releases Hydrogen Sulfide (H2S) from the sulfur containing amino acid
cysteine or cystine, or methionine
