Microbiology Biology 41
Stavney sp97
Name
Lab Quiz 4
25 points total.
Match the description on the left with the appropriate answer in the list on the right. For answers with multiple
letters, like "abd", fill in the answer rectangle for ALL of the letters ("a" AND "b" AND "d").
1. The breakdown of red blood cells
performed by pathogenic Streptococci
2. Bacteria that are oxidase negative, gram
negative rods, facultatitvely anaerobic, and
mesophilic
3. The specific species used to make bread rise
4. An organism resistant to high osmotic
pressure (salt) and low pH, produces coagulase
5. A coenocytic mold that produces asexual
sporangiospores
6. An organism that causes pharyngitis
(infection of the throat)
7. A growth medium that is BOTH selective
and differential
8. A yeast that causes vaginitis
a. nutrient agar
b. mannitol salt agar
c. Sabouraud agar
d. blood agar
e. bacitracin
ab. alpha ( 
)hemolysis
ac. beta ()hemolysis
ad. gamma ()hemolysis
ae. oxidase
bc. catalase
bd. coagulase
be. trehalose
cd. indole
ce. enterics
de. Rhizopus stolonifer
abc. Streptococcus pyogenes
abd. Streptococcus pneumoniae
abe. Rhodoturula rubra
acd. Candida albicans
ace. Aspergillus
ade. Penicillium
bcd. Staphylococcus aureus
bce. Saccharomyces cerevesiae
9. An important substance involved in
differentiating between Streptococcus
pyogenes and Streptococcus pneumoniae
10. An important substance involved in
differentiating between streptococci and
staphylococci.
11. A growth medium that contains catalase
-------------------------------------------------------------------------------------------12. When using the Enterotube, what do you do next immediately after breaking off the wire rod at the dented mark?
a. Screw the end caps back on loosely
b. Inoculate each chamber using the wire rod
c. Punch out the 8 small air holes with the short wire piece
d. Dispose of the wire end piece in the autoclave waste
e. Use a loop to burn a hole over the MRVP and Indole chambers
13. Using the key below, determine the name of the organism which has the following characteristics:
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•
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coccus shaped
colony color is yellow-red
coagulase is not produced
Microbiology
Bio 41
Quiz 4
pg 1
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•
•
•
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
mannitol is not fermented
glucose is not fermented
cells are arranged in groups of four
catalase is produced
not hemolytic
trehalose is fermented
gram positive
a. Micrococcus luteus
b. Staphylococcus saprophyticus
c. Staphylococcus arlettae
d. Staphylococcus aureus
e. Planococcus
--------------------------------------------------------------------------------------------------------------------TRUE/FALSE Answer “a” if true, and “b” if false.
14. The balloon placed over the end of the U-shaped glucose-yeast tubes was supposed
to show the production of any oxygen gas by microbes in the tube.
15. A yeast is a filamentous, unicellular organism with septate hyphae.
16. The pH of the skin is around 7.
17. Streptococcus bacteria do not produce catalase.
Microbiology
Bio 41
Quiz 4
pg 2
18. The gram stain is a useful test in separating the different kinds of bacteria that live on
the skin.
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19. Which of the pictures above shows what Candida albicans might be expected to look
like under the microscope? (Answer A-E)
20. Which of the pictures above shows what a specific mold species might look like
which grows on fruit, has white hyphae, produces green spores, and produces the first
antibiotic discovered by humans? (Answer A-E)
21. Which bacterial substance is probably produced to help the organism “hide” from
the human immune system?
a. coagulase
b. hemolysin
c. catalase
d. sebum
e. bile salts
22. Sebum is:
a. the substance produced by bacteria to hide from the immune system
b. the substance produced by bacteria to alter the pH of the skin
c. the substance added to respiratory tract bacteria to identify them
d. the substance produced by oil glands in human skin
e. the clear liquid remaining behind after red blood cells are lysed
23. One can safely conclude that a colony growing on a mannitol salt agar plate with a
yellow halo around it is :
Microbiology
Bio 41
Quiz 4
pg 3
a. soluble in bile salts and resistant to optochin
b. not soluble in bile salts and resistant to bacitracin
c. tolerant of high salt and low pH
d. able to ferment mannitol and live in high salt
e. hemolytic to some degree, and bile salt tolerant
24. Alpha hemolysis on a blood agar plate can be described as:
a. no clearing or change in the blood agar medium
b. a bluish-white halo around a colony
c. a yellow halo around a colony
d. a green, cloudy zone around a colony
e. a clear zone around a colony
25. What does Sabouraud agar contain that makes it suitable for culturing fungi?
a. high salt
b. low pH
c. optochin
d. sebum
e. phenol red
Microbiology
Bio 41
Quiz 4
pg 4