Name _____________________
ID________________________
Introduction to Microbiology (MICR2123)
Mid-Term Exam-1, June 23, 2011
Multiple Choice
Identify the choice that best completes the statement or answers the question. Each question is worth 6.25points
__c____1. The first genomes to be sequenced were those of:
a.
b.
c.
d.
e.
humans
bacteria
viruses
prions
fungi
__a___ 2. The first person to visualize live microbes was:
a.
b.
c.
d.
e.
Antoni van Leeuwenhoek
Robert Hooke
Louis Pasteur
Lady Montagu
Edward Jenner
___b__3. You have isolated a bacterium that you believe to be the causative agent of a new disease in frogs.
How would you test the third of Koch’s postulates?
a.
b.
c.
d.
e.
Determine the shape of the bacterial cells.
Inject the bacteria into a healthy frog.
Isolate the bacterium from a sick frog.
Show that the bacterium is NOT present in healthy frogs.
Grow a pure culture of the bacterium outside the frog.
__c__ 4. Resolution is best described
a.
b.
c.
d.
e.
the ability to view only stained specimen
the ability to magnify a specimen
the ability to distinguish between two closely placed objects
the ability to see internal structure of a specimen
the ability to view only unstained specimen
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ID________________________
___a__ 5. If an object and its surroundings absorb or reflect radiation equally then the object will be:
a.
b.
c.
d.
e.
undetectable
reflected
refracted
radiated
Fluoresced
___a___6. Three cells with generation times of 30 minutes are inoculated into a culture medium. How many
cells are there after 5 hours?
a.
b.
c.
d.
e.
3072
1024
243
48
16
__a____7. With the 100 x lens, the refractive index of light passing through the specimen is maintained by
insertion of __________, with a refractive index comparable to that of glass.
a.
b.
c.
d.
e.
immersion oil
water
air
bacteria
stain
___a___8. The __________ in the Gram stain process binds to the crystal violet, generating a complex that is
held more tightly within the cell.
a.
b.
c.
d.
e.
mordant
safranin
alcohol
bacteria
slide
__c__ 9. Which type of microscopy is particularly useful in studying the internal structures of a cell?
a. atomic force
b. SEM
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ID________________________
c. TEM
d. dark-field
e. bright-field
__a___10. __________ reinforce and stiffen cytoplasmic membranes in bacteria.
a.
b.
c.
d.
e.
hopanoids
polyamines
sterols
peptidoglycans
lipids
__b___11. Functions of the cytoplasmic membrane include all of the following EXCEPT:
a.
b.
c.
d.
e.
permeability barrier
assemble proteins
home to many important proteins
transport
structural support
__b___12. All archaeal phospholipids have a/an __________ link between glycerol and the lipid component.
a.
b.
c.
d.
e.
ester
ether
ethanolamine
unsaturated
phosphatidyl
__d___13. Which is NOT a component of any bacterial cells wall?
a.
b.
c.
d.
e.
peptidoglycan
techoic acids
N-acetylmuramic acid
cellulose
L-lysine
__c___14. All of the following are components of peptidoglycan EXCEPT:
a. N-acetylglucosamine
b. N-acetylmuramic acid
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c. lipopolysaccharide
d. amino acids
e. peptide cross-links
__c___15. One of the following staining techniques will help identify bacteria that have a thick, waxy-layer in
their cell wall (e.g. Mycobacterium. sp)
a.
b.
c.
d.
e.
Gram staining
capsule staining
acid-fast staining
endospore staining
flagella staining
__c___16. Lipopolysaccharides are found in:
a.
b.
c.
d.
e.
all bacteria
Gram-positive bacteria
Gram-negative bacteria
archaea
eukaryotes
_e____17. The increased stability of __________ supercoils in archaea allows them to grow in more extreme
environments.
a.
b.
c.
d.
e.
extra
negative
no
flexible
positive
__a__18. Fts proteins do which of the following?
a.
b.
c.
d.
e.
form a ring in the area where cell division will occur
aid in DNA replication
are involved in peptidoglycan synthesis
are involved in making proteins
are important in transcription
___b__19. Which name refers to having flagella attached at one or both ends of the cell?
a. peritrichous
b. lophotrichous
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ID________________________
c. monotrichous
d. pili
e. flagellated
__c___20. Bacterial movement in response to a chemical gradient in the environment is called:
a.
b.
c.
d.
e.
phototaxis
aerotaxis
chemotaxis
anytime taxi
haptotaxis
___e__ 21. Which of the following is a micronutrient?
a.
b.
c.
d.
e.
carbon
nitrogen
sulfur
calcium
zinc
__c___22. All of Earth’s life-forms are based on:
a.
b.
c.
d.
e.
hydrogen
nitrogen
oxygen
carbon
Phosphorus
__c___23. An organism that obtains energy from the light and carbon from an organic compound is called a:
a.
b.
c.
d.
e.
photoautotroph
chemoautotroph
chemoheterotroph
photoheterotroph
lithotroph
__b___24. Which of the following proteins represents a coupled transport system where two molecules travel in
the same direction?
a. aquaporin
b. symport
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Name _____________________
ID________________________
c. antiport
d. porin
e. diffusion transporters
__a___25. When the intracellular iron concentration is low, iron-scavenging molecules called __________ are
produced.
a.
b.
c.
d.
e.
siderophores
endospores
heterocysts
mycelia
quorum sensors
___c _26. All of the following are true about MacConkey medium except:
a.
b.
c.
d.
e.
it is selective.
it is differential.
it is both selective and differential.
it contains bile salts.
lactose fermenters appear colorless.
__a___27. __________ intercalates between DNA bases, causing dead cells to stain red under a fluorescence
scope.
a.
b.
c.
d.
e.
propidium iodide
Syto-9
ethidium bromide
crystal violet
safranin
__b___28. Which of the following is the best technique for counting only viable cells?
a.
b.
c.
d.
e.
direct microscopic count
spread plate
spectrophotometer
chemostat
dry weight measurements
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Name _____________________
ID________________________
__b___29. A cafeteria worker who fails to wash his hands thoroughly and fails to wear gloves inoculates a
quiche with 4 E. coli when he uses his finger to test whether it is done. By the time you purchase the
quiche, there are 128 E. coli cells in it. How many generations did the cells go through?
a.
b.
c.
d.
e.
4
5
8
32
64
__a___30. During biofilm formation, as more and more cells bind to the surface, they begin sending signals to
each other in a process called:
a.
b.
c.
d.
e.
quorum sensing
homoserine lactone
siderophores
polysaccharides
symbiosis
___a__31. Some bacteria form environmentally resistant forms called __________.
a.
b.
c.
d.
e.
endospores
heterocysts
colonies
hyphae
actinomycetes
__b___32. How do some cyanobacteria fix nitrogen while growing aerobically?
a.
b.
c.
d.
e.
they don’t because nitrogenase is destroyed by oxygen
by using special cells called heterocysts that protect the enzyme
by using cysts that protect the enzyme
they just do it, no special structures or mechanisms
they live symbiotically with other organisms that protect the enzyme
___a__33. Which of the following are used to assess which genes are expressed to make RNA in a given
organism at a given time or under a given condition?
a. DNA microarrays
b. PCR
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Name _____________________
ID________________________
c. DNA sequencing
d. fluorescence microscopy
e. viable cell counts
__c___34. Human pathogens are:
a.
b.
c.
d.
e.
halophiles
psychrophiles
mesophiles
thermophiles
extreme thermophiles
__b___35 . Psychrophiles favor the cold since their membranes are more fluid at low temperature owing to the
high proportion of __________ present.
a.
b.
c.
d.
e.
saturated fatty acids
unsaturated fatty acids
lipopolysaccharides
transport proteins
water
___e__36. __________ grow at temperatures as high as 110°C, which occur under extreme pressure.
a.
b.
c.
d.
e.
thermophiles
extreme halophiles
psychrophiles
hyperpsychrophiles
hyperthermophiles
__a___37. What percentage of microbes in our biosphere can be cultured in the laboratory?
a.
b.
c.
d.
e.
less than 10 %
approximately 20%
approximately 25%
approximately 50%
more than 90%
__c___38. Which century is known as the golden age of microbiology?
a. the seventeenth
b. the eighteenth
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Name _____________________
ID________________________
c. the nineteenth
d. the twentieth
e. the twenty-first
__d___39. Which group of microorganisms includes many that grow in extreme environments?
a.
b.
c.
d.
e.
___a___40.
algae
bacteria
protists
archaea
fungi
Which of the following pairs is mismatched?
fluorescence microscopy –uses fluorescent light source
bright-field microscopy –used to view stained specimens
confocal microscopy-produces 3-D image
electron microscopy- allows to view specimen that can’t be seen in light
microscopes
e. scanning electron microscopy-allows to view surface details of the specimen
a.
b.
c.
d.
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Name _____________________
ID________________________
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