micro lab exam ACTUAL QUESTIONS
AND CORRECT ANSWERS
Based on what you know about the Kuppelfangs' illness (fever, fatigue,
vomiting and diarrhea), what is the most likely cause? - CORRECT ANSWERS
infectious disease
Which stains are used to visualize structures in the membrane? - CORRECT
ANSWERS Acid-fast and Gram
What color do endospores and bacteria stain in an endospore stain? -
CORRECT ANSWERS Endospores green, bacteria pink
The Gram stain provides a lot of clinically useful information but it won't give
you all the information you need for identification and treatment. About which
of these do you NOT learn anything from the Gram stain? - CORRECT
ANSWERS Ability of the bacteria to process nutrients
Which type of medium supports the growth of the widest range of bacteria? -
CORRECT ANSWERS nutritive
Why is it important to have individual colonies?
-All of these statements are correct
-To look at motility
-To look at colony morphology
-To obtain a pure culture - CORRECT ANSWERS All of these
statements are correct
,What is the difference between selective and differential media? - CORRECT
ANSWERS Selective media inhibit the growth of certain bacteria,
differential media distinguish different bacteria from each other
Differential media are used to __________. - CORRECT ANSWERS
distinguish among morphologically and biochemically related groups of
organisms
What color would colonies of a non-fermenter, such as Proteus mirabilis, be on
MacConkey agar? - CORRECT ANSWERS Non-lactose fermenters do
not produce acid, and their colonies appear tan and frequently colorless.
The indole production test determines the ability of microorganisms to
__________. - CORRECT ANSWERS degrade tryptophan
Catalase breaks down which compound into water and oxygen gas? -
CORRECT ANSWERS hydrogen peroxide
If a bacterial species is aerobic, it uses oxygen as its final electron acceptor and
must have which enzyme? - CORRECT ANSWERS cytochrome oxidase
The cytochromes for the electron transport chain found in bacteria are located in
this membrane. - CORRECT ANSWERS cytoplasmic membrane
Reduction of the oxidase reagent p-aminodimethylaniline is due to which
oxidase enzyme? - CORRECT ANSWERS cytochrome oxidase
When looking at a blood agar plate with bacterial growth, beta is complete lysis
of the red blood cells, alpha is partial lysis, and gamma is no lysis. - CORRECT
ANSWERS true
, Urease test is useful for differentiating lactose-fermenting species of gram-
negative bacteria. - CORRECT ANSWERS false
The oxidase test determines if a bacterial species has a means of dealing with
hydrogen peroxide. - CORRECT ANSWERS false
Some gram-negative enteric bacteria may be catalase-positive. - CORRECT
ANSWERS true
Only prokaryotic cells have the enzyme catalase. - CORRECT ANSWERS
false
The oxidase reagent p-aminodimethylaniline oxalate is a light-pink reagent that
will turn a blackish color after reduction by cytochrome oxidase. - CORRECT
ANSWERS true
In general, moist heat kills microorganisms in less time than dry heat. -
CORRECT ANSWERS true
Sensitivity to an antimicrobial agent generally corresponds to small zones of
inhibition. - CORRECT ANSWERS false
When two antimicrobial agents cause a greater effect when present together
than either causes alone, synergism has occurred. - CORRECT ANSWERS
true
Antibiotics are synthetic chemicals. - CORRECT ANSWERS false
A bactericidal chemical kills bacteria. - CORRECT ANSWERS true
AND CORRECT ANSWERS
Based on what you know about the Kuppelfangs' illness (fever, fatigue,
vomiting and diarrhea), what is the most likely cause? - CORRECT ANSWERS
infectious disease
Which stains are used to visualize structures in the membrane? - CORRECT
ANSWERS Acid-fast and Gram
What color do endospores and bacteria stain in an endospore stain? -
CORRECT ANSWERS Endospores green, bacteria pink
The Gram stain provides a lot of clinically useful information but it won't give
you all the information you need for identification and treatment. About which
of these do you NOT learn anything from the Gram stain? - CORRECT
ANSWERS Ability of the bacteria to process nutrients
Which type of medium supports the growth of the widest range of bacteria? -
CORRECT ANSWERS nutritive
Why is it important to have individual colonies?
-All of these statements are correct
-To look at motility
-To look at colony morphology
-To obtain a pure culture - CORRECT ANSWERS All of these
statements are correct
,What is the difference between selective and differential media? - CORRECT
ANSWERS Selective media inhibit the growth of certain bacteria,
differential media distinguish different bacteria from each other
Differential media are used to __________. - CORRECT ANSWERS
distinguish among morphologically and biochemically related groups of
organisms
What color would colonies of a non-fermenter, such as Proteus mirabilis, be on
MacConkey agar? - CORRECT ANSWERS Non-lactose fermenters do
not produce acid, and their colonies appear tan and frequently colorless.
The indole production test determines the ability of microorganisms to
__________. - CORRECT ANSWERS degrade tryptophan
Catalase breaks down which compound into water and oxygen gas? -
CORRECT ANSWERS hydrogen peroxide
If a bacterial species is aerobic, it uses oxygen as its final electron acceptor and
must have which enzyme? - CORRECT ANSWERS cytochrome oxidase
The cytochromes for the electron transport chain found in bacteria are located in
this membrane. - CORRECT ANSWERS cytoplasmic membrane
Reduction of the oxidase reagent p-aminodimethylaniline is due to which
oxidase enzyme? - CORRECT ANSWERS cytochrome oxidase
When looking at a blood agar plate with bacterial growth, beta is complete lysis
of the red blood cells, alpha is partial lysis, and gamma is no lysis. - CORRECT
ANSWERS true
, Urease test is useful for differentiating lactose-fermenting species of gram-
negative bacteria. - CORRECT ANSWERS false
The oxidase test determines if a bacterial species has a means of dealing with
hydrogen peroxide. - CORRECT ANSWERS false
Some gram-negative enteric bacteria may be catalase-positive. - CORRECT
ANSWERS true
Only prokaryotic cells have the enzyme catalase. - CORRECT ANSWERS
false
The oxidase reagent p-aminodimethylaniline oxalate is a light-pink reagent that
will turn a blackish color after reduction by cytochrome oxidase. - CORRECT
ANSWERS true
In general, moist heat kills microorganisms in less time than dry heat. -
CORRECT ANSWERS true
Sensitivity to an antimicrobial agent generally corresponds to small zones of
inhibition. - CORRECT ANSWERS false
When two antimicrobial agents cause a greater effect when present together
than either causes alone, synergism has occurred. - CORRECT ANSWERS
true
Antibiotics are synthetic chemicals. - CORRECT ANSWERS false
A bactericidal chemical kills bacteria. - CORRECT ANSWERS true
