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Final Lab Practical
Written Version
Name
100 pts. (All multiple choice worth 2 pts each).
1. What is the total
magnification of the
microscope with the
lenses in the current
position?
a. 4X
b. 40X
c. 10X
d. 100X
e. 1000X
2. What is the name
of the microscope
structure marked
by the arrow V?
a. objective
b. ocular
c. condenser
d. iris diaphragm
e. nosepiece
3. Which objective in the list below focuses closest to the slide?
a. 4X
b. 10X
c. 20X
d. 40X
e. 100X
4. What is the function of the microscope structure above labeled VI.?
a. move the objectives up and down in focusing
b. focus the light from the lamp onto the specimen
c. regulate the amount of light falling on the specimen
d. magnify the image from the specimen
e. increase or decrease the numerical aperture
5. Examine the view of the slide under a microscope shown at the right. To what Kingdom does this
organism belong?
a. Fungi
b. Protista
c. Animalia
d. Monera
e. Plantae
6. Give the correct scientific term that describes the shape of these organisms in question 5:
Bio 41 Written Final Lab Exam pg 1
a. filamentous
b. bacillus
c. coccus
d. ovoid
e. spirillum
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7. Which instrument or tool above is used to inoculate agar deeps? Answer A-E.
8. Which tool or instrument above is commonly used to inoculate agar slants?
-------------------------------------------------9. The same bacterial species was inoculated into several glucose fermentation tubes, shown at the
right. What chemical substance
probably caused the color change
in tube B?
a. acid
b. acetoin
c. ammonia
d. oxidase
e. catalase
10. In the glucose fermentation tubes above, Tubes A and B were inoculated at the same time, but have
been incubating for different periods of time. How old would you predict the culture to be in Tube B?
a. less than 1 hour
b. 1 hour
c. 10 hours
d. 24 hours
e. 48 hours
11. What are the characteristics of a bacterium that could cause the condition known as pharyngitis?
a. catalase positive, oxidase negative cocci
b. beta hemolytic, bacitracin sensitive cocci
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c. beta hemolytic, catalase positive cocci
d. gamma hemolytic, oxidase positive cocci
e. beta hemolytic, catalase negative bacilli
12. What is the name of a bacterial species that causes pharyngitis?
a. Staphylococcus aureus
b. Streptococcus sanguis
c. Proteus vulgaris
d. Streptococcus mutans
e. Streptococcus pyogenes
13. A urine sample from a patient was diluted
and plated on blood agar as shown in the
diagram above. What is the concentration of
bacteria in the patient’s urine?
a. 2800 bacteria/ml
b. 2.8 x 10-3 bacteria/ml
c. 2.8 x 104 bacteria/ml
d. 2.8 x 105 bacteria/ml
e. 2.8 x 103 bacteria/ml
14. What can you safely conclude about the patient above from whom the urine sample was taken?
a. the person does not have a urinary tract infection
b. the person has E. coli in his/her urine
c. the person has a Candida infection
d. the person has urinary tract infection
e. the person has been eating too much sugar
------------------------------------------------------15. What is the purpose of flaming the mouth of a tube during bacterial transfers?
a. to kill and decontaminate the culture inside the tube
b. to provide heat to enhance growth of transferred bacteria
c. to cause upward air currents that prevent contamination when the tube is open
d. to add heat so that the cap will seal properly on the tube top
e. to warm the tube so that it is easier to hold
16. Examine the streaking on the plate at the right. What is the purpose of streaking a plate in this
fashion?
a. to increase the concentration of bacteria on the plate
b. to produce a “lawn” of bacterial colonies
c. to cover as much of the plate as possible
d. to isolate single colonies by spreading the bacteria widely
e. to cool off the loop gradually so the bacteria will survive
17. A sucrose blood agar plate is inoculated with saliva. What type of bacterial product is being
formed by the smooth, mucoid colonies?
a. acetoin
b. ethanol and CO2
c. catalase
Bio 41 Written Final Lab Exam pg 3
d. dextran
e. amylase
18.What two things are required for dental decay to occur?
a. lactose and bacteria
b. acid and base
c. blood and living tissue
d. bacteria and sucrose
e. glucose and bacteria
19. What type of medium is shown at the right,
when used with respiratory tract bacteria?
a. selective (only)
b. enriching (only)
c. differential (only)
d. selective and differential
e. differential and enriching
20. What metabolic activity is seen on this
plate above in question 19?
a. alpha hemolysis
b. mannitol fermentation
c. starch hydrolysis
d. gamma hemolysis
e. beta hemolysis
21. The best kind of stains that sick to bacterial cells are usually:
a. nigrosines
b. basic
c. acidic
d. neutral
e. negative
22. In the hanging drop procedure, what was the purpose of laying down a line of water or vaseline
around the edge of the coverslip?
a. to get the organisms to stick to the slide
b. to create a depression for the droplet to hang in
c. to prevent evaporation of the droplet
d. to slow down the movement of the organisms in the droplet
e. to provide food to the specimen so that it lives longer
23. The agar slant medium at the right was used to study and separate bacteria that cause urinary tract
infections. This medium can indicate the production of which of the following bacterial enzyme(s)?
a. catalase
b. sugar fermentation enzymes
Urea agar
c. sugar oxidation enzymes
d. peptone degrading enzymes
e. urease
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24. What substance causes the color change in the inoculated tube shown in question 23?
a. ammonia
b. lactic acid
c. pyruvate
d. acetoin
e. urea
25. The growth medium at the right is designed to select for a bacterial species that lives in which part
of the healthy human body?
a. mouth
b. gastrointestinal tract
c. upper respiratory tract
d. skin
e. urogenital tract
Tomato Juice Agar
26. Which of the following is TRUE about the organisms that grow best on the medium shown in
question 25?
a. they are gram negative
b. they are spirilla shaped
c. they produce coagulase
d. they are catalase negative
e. they produce dextran or levan
27. In the staining procedure using the substances below, which substance acts as the mordant?
Answer A-E.
28. A slide has just received a transfer of bacteria into a few drops of water, and has dried. What is
the very next step you would take, assuming you wished to stain the bacteria with a simple stain?
a. add the stain
b. heat fix
c. wash with ethanol
d. blot the slide
e. wash with water
29. In gram staining, what color would a gram negative bacterium be during the step where iodine has
just been added?
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a. violet/purple
b. pinkish red
c. light blue
d. orange
e. colorless
30. Ethanol normally interacts with which of the following substances found in a gram negative cell
(during a Gram Stain)?
a. protein
b. murein
c. phospholipids
d. DNA
e. safranin
31. Some bacteria are grown on a Petri plate in an anaerobic jar. During incubation, the methylene
blue stick turned white inside of the jar. The colonies on the Petri plate bubbled within hydrogen
peroxide was added.
The colonies on the plate must be:
a. obligate anaerobes
b. facultative anaerobes
c. obligate aerobes
d. aerotolerant anaerobes
e. neither aerobes nor anaerobes
32. What gas is produced from the foil gas package in order to react with free oxygen?
a. carbon dioxide
b. hydrogen
c. ammonia
d. water vapor
e. methane
33. In the MRVP tubes at the right, methyl red was added to tube I and VP reagents were added to tube
II. Both tubes had previously been inoculated with a single bacterial species and incubated for 24
hours.
What product(s) was/were produced by the
bacteria inoculated into these tubes?
a. acid
b. ethanol and CO2
c. acetoin
d. amylase
e. urease
34. What chemical process is the MRVP test designed to investigate?
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a. starch hydrolysis
b. catalase activity
c. glucose oxidation
d. glucose fermentation
e. peptone catabolism
35. Which medium at the right would be
best suited for culturing skin bacteria? Answer A-E.
MSB agar
C
PEA
A
Sabouraud agar
D
mannitol salt agar
B
SF broth
E
36. Which medium above would be best suited for culturing fungi? Answer A-E.
-----------------------------------------------------------------------37. The growth medium at the right was inoculated with a sample from the appropriate part of the
human body.
The colonies growing on this plate should all be:
a oxidase negative
b. catalase negative
white
c. gram positive
colored
d. hemolytic (alpha or gamma)
e. anaerobic
MacConkey Agar
38. According to the growth on the plate shown on the plate in question 37, most of the isolated
colonies appear to be:
a. mannitol fermenters
b. starch hydrolyzers
c. non-coliforms
d. coagulase positive
e. salt tolerant
39. At the right are some pairs of OF glucose tubes. The pair of OF glucose tubes labeled I and II were
both inoculated with the same organism. From the results, one can conclude that this organism can:
a. only oxidize glucose
b. both oxidize and ferment glucose
c. only ferment glucose
d. not use glucose at all
e. can convert glucose into acetoin
40. What has occurred in the 24 hour OF
glucose tube labeled III in the diagram above?
a. glucose was oxidized
b. glucose was fermented
c. glucose was both oxidized and fermented
d. peptone was catabolized
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e. the organism did not grow at all
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SHORT ANSWER PAGE
Name
20 pts. Tear off this page, complete the questions, and fold in half lengthwise. Write the first three
letters of your last name on the back.
1. 4 pts. Name one similarity and one difference between a coliform enteric and a non-coliform
enteric.
Similarity:
Difference:
2. 4 pts. Suppose you have a colony on a plate that is either a Streptococcus or a Staphylococcus
species. How could you determine fairly quickly and reliably which genus it is? Describe the test or
process and what the results mean.
4. 2 pts. Write the full scientific name of a spore-forming bacterium, using proper scientific format.
5. 2 pts. Write the full scientific name of a gram positive bacterium that lives in the gastrointestinal
tract. Use proper scientific format.
6. 2 pts. Write the full scientific name of a bacterium that causes dental caries (cavities). Use proper
scientific format.
7. 2 pts. Define the term yeast, using as many details as possible.
8. 2 pts. Name the type of bacterial arrangement shown in
the picture at the right. Use scientific terminology.
9. 2 pts. Name the type of growth shown in the agar slant.
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