Elsevier: Microbiology Exam Questions and Answers
1. Spores are found in select 1. a. Some bacteria form thick-walled structures
groups ofbacteria.Which of termed spores. These structures are formed during
the following statements describes the a process that makes a copy of a chromosome and
major advantage to the bacteria that encloses it with a thick protein coat. This spore is
possess these structures? resistant to heat, cold, drying, most chemicals,
a.Spores are resistant to heat, cold, drying, and boiling. Spores can remain viable for many
most chemicals, and boiling years in soil or dust.
b. Spores allow an organism to better
control its local environment
c.Spores allow bacteria to attach or
adhere to host tissues
d. Organisms with spores have a more
efficient
2. Choose the binomial name that is 2. c. Genus and species are italicized or underlined. Genus is capitalized; species is
correctly written. lowercase.
a.Staphylococcus Aureus
b. Staphylococcus species aureus
c.Staphylococcus aureus
d. Staphylococcus aureus
3. Fermentation end-products are often 3. b. Bacterial cells generate stored energy in the form of ATP by one of two basic
used to aid in mechanisms: respiration or fermentation. Fermentation is metabolism in the absence
the identification of bacteria. Fermentation of oxygen, an anaerobic process. In fermentation, glucose is converted into
results pyruvate by either the Embdem-Meyerhof pathway or glycolysis. Pyruvate can then
in which of the following? enter several other cycles, and the end-products vary depending on cycle entered.
a.Conversion of glucose to pyruvate In aerobic respiration, glucose usage under aerobic conditions and pyruvate enters
b. Lactic acid, mixed acids, alcohols, CO2 the Kreb's cycle (TCA cycle). The end-products of respiration are carbon dioxide and
production water. The unique metabolic pathways and end-products produced by bacteria can
c.CO2 and water be used to aid in the identification of particular genera or species
d. Specific teichoic acids
,4. The exchange of cellular DNA between 4. d. Bacteria can acquire or exchange genetic material with other bacteria through
two living several basic mechanisms: conjugation, transformation, or transduction. Conjugation
bacterial cells that involves an intercellular involves cell-to-cell contact, a series of complex chemical signals between cells, and
bridge usually the formation of a bridge or sex pilus. Transformation is the uptake of free
is which of the following processes? DNA by a recipient cell. Transduction is the acquisition of DNA through the action of
a.Transformation a bacteria phage.
b.Transduction
c. Plasmidization
d. Conjugation
5. Transduction is defined as which of the 5. d. Transduction refers to moving genetic information from one prokaryote to
following? another via a bacteriophage or virus
a. The change of the bacterial
genotypesthrough
the exchange of DNA from one cell to
another
b.An internal change in the original
nucleotide
sequence of a gene or genes within an
organism's genome
c.The process by which genetic elements
such as plasmids and transposons excise
from one genomic location and insert into
another
d.A mechanism that is mediated by viruses,
by which DNA from two bacteria may
come together in one cell, thus allowing
for recombination
6. A mordant that is applied after the 6. c. The Gram stain procedure involves four steps: applying crystal violet—the initial
primary stain to purple dye that enters the cell; applying Gram's iodine—the mordent or chemical that
chemically bond the alkaline dye to the binds to the crystal violet forming a complex; decolorizing—alcohol or
bacterial cell acetone/alcohol is used to remove the crystal violet/ iodine complex from gram-
wall is which of the following? negative cells; and safranin counter stain—the red dye is used as a second stain.
a.Safranin Gram-positive bacteria retained the initial crystal violet, the red counter stain blends
b.Crystal violet with the violet, and gram-negative bacteria are only stained with the safranin and
c.Gram's iodine appear red.
d. Gram's decolorizer
7. Which of the following bacteria should 7. d. Although many different bacteria can be isolated from skin and soft tissue
be considered infections, the two most common organisms are Staphylococcus aureus and
important pathogens when reading gram- Streptococcus pyogenes. We should be aware of these likely organisms as we read
stained and report gram-stained smear results. S. pneumoniae and N. gonorrhoeae are
smears of soft tissue abscess? important pathogens but rarely associated with skin infections. Although
a.Streptococcus pneumoniae Pseudomonas can be associated with some unique infections of the skin, they are
b. Neisseria gonorrhoeae uncommon.
c. Pseudomonas aeruginosa
d. Staphylococcus aureus
, 8. The most appropriate interpretation of a 8. d. The two major uses for gram-stained smears are to evaluate the quality of a
gramstained smear of a sputum specimen specimen (inflammation versus normal flora contamination) and describe the types
would be which of the following? (gram- of bacteria—gram-positive versus gramnegative. For sputum specimens,
stained smear, expectorated lower respiratory tract specimens, the following criteria are often
400.) applied: (1) more than 25 epithelial cells/low-power field=saliva, significant number
a.Few epithelial cells, many PMNs of normal flora bacteria. (2) Few epithelial cells, many white blood cells¼specimen
b. Inadequate specimen, do not culture for more likely to yield a pathogen. In adult patients, specimens with significant numbers
anaerobes of epithelial cells often are not cultured and new samples are collected.
c. Many cells, many gram-positive cocci in
pairs and
chains
d. More than 25 epithelial cells, probable
oral contamination, suggest recollect
9. 85% N2, 10% H2, 5% CO2 is the 9. b. The atmosphere in which specimens are incubated can have a significant effect
environmental on the growth of potential pathogens. Many bacteria isolates will grow easily in
condition that best suits which type of routine air or with a slight increase in carbon dioxide, 3% to 5% CO2 (aerobes). Other
organism? pathogens require special atmospheres for optimal growth, including increased CO2,
a.Aerobes nitrogen, or decreased or complete absence of oxygen: Microaerophilic: 5% O2, 10%
b.Anaerobes CO2, 85% N Anaerobic: 85% N2, 10% H2, 5% CO2
c.Capnophiles
d. Microaerophiles
10.Whichmedium can be described 10. d. Hektoen enteric (HE) contains meat peptones and yeast extract, bile salts
ascontaining bile salts (inhibit gram-positive organisms), lactose, sucrose, salacin (carbohydrate sources),
and dyes (bromothymol blue and acid pH indicators (bromophenol blue and acid fuchsin), and ferric ammonium citrate for
fuchsin) to selectively slow the growth of the detection of H2S production. This medium is very selective for enteric pathogens
most nonpathogenic gramnegative bacilli and is differential for Salmonella and Shigella. Yellow-orange colonies¼lactose
found in the gastrointestinal tract fermenter (E. coli), colorless/ green colonies with unchanged medium¼non- lactose
and allow Salmonella spp. and Shigella fermenter (Shigella, Providencia), and black colonies¼H2S production (Salmonella).
spp. to grow?
a.Thayer-Martin
b. MacConkey
c. PEA (phenylethyl alcohol)
d. Hektoen
11. Choose the group of bacteria 11. c. The genus Staphylococcus represents one of the most important groups of
that is described as potentially pathogenic bacteria and most common normal flora organisms. This
catalase-positive, gram-positive cocci that genus has the general characteristics of gram-positive cocci in clusters and is
grow facultatively anaerobic and that form catalasepositive, facultative anaerobic, ferments glucose, and nonmotile.
grapelike clusters.
a.Neisseria spp.
b. Rothia (Stomatococcus) spp.
c.Staphylococcus spp.
d. Micrococcus spp.
12. The slide coagulase test is 12. a. A unique pathogenic factor of Staphylococcus aureus is the production of
a rapidscreening test for coagulase. This protein is responsible for the formation of fibrin clots in the host.
the production of which of the following? Coagulase is found in two basic forms: bound to the surface of the cell, also known
a.Clumping factor as clumping factor, and free in the medium. The bound form can be detected with
b. Free coagulase several tests that demonstrate clumping of the bacterial cell or sensitized red blood
c. Extracellular coagulase cells, and the free form is most often detected by clot formation with rabbit plasma
d. Catalase
1. Spores are found in select 1. a. Some bacteria form thick-walled structures
groups ofbacteria.Which of termed spores. These structures are formed during
the following statements describes the a process that makes a copy of a chromosome and
major advantage to the bacteria that encloses it with a thick protein coat. This spore is
possess these structures? resistant to heat, cold, drying, most chemicals,
a.Spores are resistant to heat, cold, drying, and boiling. Spores can remain viable for many
most chemicals, and boiling years in soil or dust.
b. Spores allow an organism to better
control its local environment
c.Spores allow bacteria to attach or
adhere to host tissues
d. Organisms with spores have a more
efficient
2. Choose the binomial name that is 2. c. Genus and species are italicized or underlined. Genus is capitalized; species is
correctly written. lowercase.
a.Staphylococcus Aureus
b. Staphylococcus species aureus
c.Staphylococcus aureus
d. Staphylococcus aureus
3. Fermentation end-products are often 3. b. Bacterial cells generate stored energy in the form of ATP by one of two basic
used to aid in mechanisms: respiration or fermentation. Fermentation is metabolism in the absence
the identification of bacteria. Fermentation of oxygen, an anaerobic process. In fermentation, glucose is converted into
results pyruvate by either the Embdem-Meyerhof pathway or glycolysis. Pyruvate can then
in which of the following? enter several other cycles, and the end-products vary depending on cycle entered.
a.Conversion of glucose to pyruvate In aerobic respiration, glucose usage under aerobic conditions and pyruvate enters
b. Lactic acid, mixed acids, alcohols, CO2 the Kreb's cycle (TCA cycle). The end-products of respiration are carbon dioxide and
production water. The unique metabolic pathways and end-products produced by bacteria can
c.CO2 and water be used to aid in the identification of particular genera or species
d. Specific teichoic acids
,4. The exchange of cellular DNA between 4. d. Bacteria can acquire or exchange genetic material with other bacteria through
two living several basic mechanisms: conjugation, transformation, or transduction. Conjugation
bacterial cells that involves an intercellular involves cell-to-cell contact, a series of complex chemical signals between cells, and
bridge usually the formation of a bridge or sex pilus. Transformation is the uptake of free
is which of the following processes? DNA by a recipient cell. Transduction is the acquisition of DNA through the action of
a.Transformation a bacteria phage.
b.Transduction
c. Plasmidization
d. Conjugation
5. Transduction is defined as which of the 5. d. Transduction refers to moving genetic information from one prokaryote to
following? another via a bacteriophage or virus
a. The change of the bacterial
genotypesthrough
the exchange of DNA from one cell to
another
b.An internal change in the original
nucleotide
sequence of a gene or genes within an
organism's genome
c.The process by which genetic elements
such as plasmids and transposons excise
from one genomic location and insert into
another
d.A mechanism that is mediated by viruses,
by which DNA from two bacteria may
come together in one cell, thus allowing
for recombination
6. A mordant that is applied after the 6. c. The Gram stain procedure involves four steps: applying crystal violet—the initial
primary stain to purple dye that enters the cell; applying Gram's iodine—the mordent or chemical that
chemically bond the alkaline dye to the binds to the crystal violet forming a complex; decolorizing—alcohol or
bacterial cell acetone/alcohol is used to remove the crystal violet/ iodine complex from gram-
wall is which of the following? negative cells; and safranin counter stain—the red dye is used as a second stain.
a.Safranin Gram-positive bacteria retained the initial crystal violet, the red counter stain blends
b.Crystal violet with the violet, and gram-negative bacteria are only stained with the safranin and
c.Gram's iodine appear red.
d. Gram's decolorizer
7. Which of the following bacteria should 7. d. Although many different bacteria can be isolated from skin and soft tissue
be considered infections, the two most common organisms are Staphylococcus aureus and
important pathogens when reading gram- Streptococcus pyogenes. We should be aware of these likely organisms as we read
stained and report gram-stained smear results. S. pneumoniae and N. gonorrhoeae are
smears of soft tissue abscess? important pathogens but rarely associated with skin infections. Although
a.Streptococcus pneumoniae Pseudomonas can be associated with some unique infections of the skin, they are
b. Neisseria gonorrhoeae uncommon.
c. Pseudomonas aeruginosa
d. Staphylococcus aureus
, 8. The most appropriate interpretation of a 8. d. The two major uses for gram-stained smears are to evaluate the quality of a
gramstained smear of a sputum specimen specimen (inflammation versus normal flora contamination) and describe the types
would be which of the following? (gram- of bacteria—gram-positive versus gramnegative. For sputum specimens,
stained smear, expectorated lower respiratory tract specimens, the following criteria are often
400.) applied: (1) more than 25 epithelial cells/low-power field=saliva, significant number
a.Few epithelial cells, many PMNs of normal flora bacteria. (2) Few epithelial cells, many white blood cells¼specimen
b. Inadequate specimen, do not culture for more likely to yield a pathogen. In adult patients, specimens with significant numbers
anaerobes of epithelial cells often are not cultured and new samples are collected.
c. Many cells, many gram-positive cocci in
pairs and
chains
d. More than 25 epithelial cells, probable
oral contamination, suggest recollect
9. 85% N2, 10% H2, 5% CO2 is the 9. b. The atmosphere in which specimens are incubated can have a significant effect
environmental on the growth of potential pathogens. Many bacteria isolates will grow easily in
condition that best suits which type of routine air or with a slight increase in carbon dioxide, 3% to 5% CO2 (aerobes). Other
organism? pathogens require special atmospheres for optimal growth, including increased CO2,
a.Aerobes nitrogen, or decreased or complete absence of oxygen: Microaerophilic: 5% O2, 10%
b.Anaerobes CO2, 85% N Anaerobic: 85% N2, 10% H2, 5% CO2
c.Capnophiles
d. Microaerophiles
10.Whichmedium can be described 10. d. Hektoen enteric (HE) contains meat peptones and yeast extract, bile salts
ascontaining bile salts (inhibit gram-positive organisms), lactose, sucrose, salacin (carbohydrate sources),
and dyes (bromothymol blue and acid pH indicators (bromophenol blue and acid fuchsin), and ferric ammonium citrate for
fuchsin) to selectively slow the growth of the detection of H2S production. This medium is very selective for enteric pathogens
most nonpathogenic gramnegative bacilli and is differential for Salmonella and Shigella. Yellow-orange colonies¼lactose
found in the gastrointestinal tract fermenter (E. coli), colorless/ green colonies with unchanged medium¼non- lactose
and allow Salmonella spp. and Shigella fermenter (Shigella, Providencia), and black colonies¼H2S production (Salmonella).
spp. to grow?
a.Thayer-Martin
b. MacConkey
c. PEA (phenylethyl alcohol)
d. Hektoen
11. Choose the group of bacteria 11. c. The genus Staphylococcus represents one of the most important groups of
that is described as potentially pathogenic bacteria and most common normal flora organisms. This
catalase-positive, gram-positive cocci that genus has the general characteristics of gram-positive cocci in clusters and is
grow facultatively anaerobic and that form catalasepositive, facultative anaerobic, ferments glucose, and nonmotile.
grapelike clusters.
a.Neisseria spp.
b. Rothia (Stomatococcus) spp.
c.Staphylococcus spp.
d. Micrococcus spp.
12. The slide coagulase test is 12. a. A unique pathogenic factor of Staphylococcus aureus is the production of
a rapidscreening test for coagulase. This protein is responsible for the formation of fibrin clots in the host.
the production of which of the following? Coagulase is found in two basic forms: bound to the surface of the cell, also known
a.Clumping factor as clumping factor, and free in the medium. The bound form can be detected with
b. Free coagulase several tests that demonstrate clumping of the bacterial cell or sensitized red blood
c. Extracellular coagulase cells, and the free form is most often detected by clot formation with rabbit plasma
d. Catalase
