QUESTIONS AND ANSWERS WITH COMPLETE SOLUTIONS lOMoARcPSD| 69811638
UAMS MICROBIOLOGY EXAM 1
QUESTIONS AND ANSWERS WITH
COMPLETE SOLUTIONS GUARANTEED
SUCCESS!!!
Microbiology: Nutritionally Variant Streptococci (NVS)
What are the primary genera of Nutritionally Deficient / Variant
Streptococci (NVS)?
✔✔ Abiotrophia and Granulicatella species.
Why do Nutritionally Variant Streptococci fail to grow on routine blood
agar (BAP) or chocolate agar (CHOC) media?
✔✔ They are deficient in specific nutritional factors, specifically Vitamin
B6 (pyridoxal / pyridoxamine).
How is the "satellite phenomenon" utilized in the laboratory to cultivate
Nutritionally Variant Streptococci?
✔✔ A routine blood agar plate is inoculated with the NVS specimen, and
a Staphylococcus aureus streak is made down the center (or across the
plate). The S. aureus colonies excrete the necessary Vitamin B6
metabolites into the agar, allowing small "satellite" colonies of NVS to
grow closely adjacent to the S. aureus streak line.
Coccus, coccobacillus, vibrio, bacillus, spirillum, and spirochete. -
ANSWER✔✔What are the different morphologies of bacteria?
Coccus (one single colony), diplococci (two colonies), staphylococci
(multiple colonies in a triangle shape), streptococci (multiple colonies in a
linear row), sarcina (multiple colonies that can be on top of one another in
a square shape), and tetrad (four colonies in a square). -
ANSWER✔✔What are the different bacterial arrangements for cocci?
Rod shaped. The genus (Bacillus anthracis). Single bacillus, diplobacilli,
streptobacilli, and palisade (rods laid side by side, forming a fence-like
appearance; can also be V-shaped). -ANSWER✔✔What does bacillus or
bacilli refer to? What about Bacillus? What are the bacilli arrangements?
)
, QUESTIONS AND ANSWERS WITH COMPLETE SOLUTIONS lOMoARcPSD| 69811638
Bacteria that is capable of altering its morphology to take on many
different shapes. -ANSWER✔✔What does the term pleomorphic refer to?
Ex. Pleomorphic bacilli
Spores are cells with very thick walls that can survive many extremes,
allowing a bacterium protection in order to preserve its genetic material. -
ANSWER✔✔What are spores and what do they allow a bacterium, such
as bacilli with spores?
Filamentous and fusiform. -ANSWER✔✔What are the two different
forms of bacilli rods?
Hans Christian Gram. Crystal violet, iodine, decolorizer, and safranin. The
cell wall structure of the bacteria is what determines if it is gram pos or
neg. The thick peptidoglycan layer on gram pos MOs retains the crystal
violet-iodine complex. On gram neg MOs, there is only a thin layer of
peptidoglycan under a layer of lipids. The lipid layer retains the stain and
the decolorizer then dissolves the lipid layer, removing the crystal violet-
iodine complex. -ANSWER✔✔Who invented the Gram stain and staining
method? What are the reagents involved? How is Gram stain able to
work? What makes some bacteria gram pos and others neg?
Safranin. Once the decolorizer dissolves the lipid layer holding the crystal
violet-iodine complex, the safranin is able to stain the thin peptidoglycan
layer underneath, causing the bacteria to appear pink. The pink bacteria
can then be identified as Gram neg. -ANSWER✔✔What is the counter
stain that is used alongside Gram stain to identify the Gram neg bacteria?
How does this work?
Cells from a culture are taken and spread over a thin area of a slide and
then heat fixed. The smear doesn't need to be too thin or too thick,
otherwise it will be unable to be read properly. Smears are heat fixed using
a bunsen burner, an electric incinerator, or methanol. This is done to kill
the bacteria on the slide, prevent bacteria from washing off the slide, and
allowing the smear to take up stain better. -ANSWER✔✔What is smear?
)
, QUESTIONS AND ANSWERS WITH COMPLETE SOLUTIONS lOMoARcPSD| 69811638
What is important when preparing a smear? How are smears heat fixed
and why?
Place the slide on a staining rack and cover the smear with crystal violet
solution. Let stand for 30-60 seconds. Rinse with tap water to remove the
crystal violet, then shake off excess water. Cover the smear with Gram's
iodine and let stand for 30-60 seconds. Rinse with water, then shale off
excess. Decolorize the smear with acetone-alcohol and rinse with water as
soon as the purple/blue color no longer runs off the slide. *Be careful to
not over or under decolorize* Shake off excess water and counterstain
with safranin for 30 seconds, rinse with water, and dry slide by air or by
blotting. -ANSWER✔✔What is the Gram staining procedure?
Gram neg cells such as human cells will appear washed out and gram pos
bacteria will appear gram neg or partially stained. Gram neg cells such as
human cells will appear dark red / purple and other gram neg bacteria
appear gram pos. -ANSWER✔✔What will happen is the decolorizer is left
on too long? What about under-decolorized?
Damaged cells are a potential problem when looking at older culture, they
will not take up stain. This can be due to antibiotics. Overheating a slide
distorts cells from their normal shape, causing them to look weird when
viewing. Improper reagent use can be a source of error when one is
omitted or they are used in the wrong order. Excessive rinsing can wash
out the crystal violet or crystal violent iodine complex away, Prolonged
counterstaining might cause the crystal violet complex to be leached from
the Gram pos MOs. -ANSWER✔✔How will damaged cells pose as a
source of error when staining? How does overheating a slide pose as a
source of error? What about improper reagent use? What about excessive
rinsing and prolonged counterstaining?
Media is used to culture specimens, isolate bacteria, biochemicals used for
identification, and used for antibiotic susceptibility.
Liquid broth, semi-solid agar (0.3-0.5%), agar slants, and solid agar (1-
2%). Polysaccharide is the main component, melting at 100 C and staying
liquid until 45-50 C. Different agars are created by using different
amounts of polysaccharide. Semi-solid has less, whereas solid has more. -
)
UAMS MICROBIOLOGY EXAM 1
QUESTIONS AND ANSWERS WITH
COMPLETE SOLUTIONS GUARANTEED
SUCCESS!!!
Microbiology: Nutritionally Variant Streptococci (NVS)
What are the primary genera of Nutritionally Deficient / Variant
Streptococci (NVS)?
✔✔ Abiotrophia and Granulicatella species.
Why do Nutritionally Variant Streptococci fail to grow on routine blood
agar (BAP) or chocolate agar (CHOC) media?
✔✔ They are deficient in specific nutritional factors, specifically Vitamin
B6 (pyridoxal / pyridoxamine).
How is the "satellite phenomenon" utilized in the laboratory to cultivate
Nutritionally Variant Streptococci?
✔✔ A routine blood agar plate is inoculated with the NVS specimen, and
a Staphylococcus aureus streak is made down the center (or across the
plate). The S. aureus colonies excrete the necessary Vitamin B6
metabolites into the agar, allowing small "satellite" colonies of NVS to
grow closely adjacent to the S. aureus streak line.
Coccus, coccobacillus, vibrio, bacillus, spirillum, and spirochete. -
ANSWER✔✔What are the different morphologies of bacteria?
Coccus (one single colony), diplococci (two colonies), staphylococci
(multiple colonies in a triangle shape), streptococci (multiple colonies in a
linear row), sarcina (multiple colonies that can be on top of one another in
a square shape), and tetrad (four colonies in a square). -
ANSWER✔✔What are the different bacterial arrangements for cocci?
Rod shaped. The genus (Bacillus anthracis). Single bacillus, diplobacilli,
streptobacilli, and palisade (rods laid side by side, forming a fence-like
appearance; can also be V-shaped). -ANSWER✔✔What does bacillus or
bacilli refer to? What about Bacillus? What are the bacilli arrangements?
)
, QUESTIONS AND ANSWERS WITH COMPLETE SOLUTIONS lOMoARcPSD| 69811638
Bacteria that is capable of altering its morphology to take on many
different shapes. -ANSWER✔✔What does the term pleomorphic refer to?
Ex. Pleomorphic bacilli
Spores are cells with very thick walls that can survive many extremes,
allowing a bacterium protection in order to preserve its genetic material. -
ANSWER✔✔What are spores and what do they allow a bacterium, such
as bacilli with spores?
Filamentous and fusiform. -ANSWER✔✔What are the two different
forms of bacilli rods?
Hans Christian Gram. Crystal violet, iodine, decolorizer, and safranin. The
cell wall structure of the bacteria is what determines if it is gram pos or
neg. The thick peptidoglycan layer on gram pos MOs retains the crystal
violet-iodine complex. On gram neg MOs, there is only a thin layer of
peptidoglycan under a layer of lipids. The lipid layer retains the stain and
the decolorizer then dissolves the lipid layer, removing the crystal violet-
iodine complex. -ANSWER✔✔Who invented the Gram stain and staining
method? What are the reagents involved? How is Gram stain able to
work? What makes some bacteria gram pos and others neg?
Safranin. Once the decolorizer dissolves the lipid layer holding the crystal
violet-iodine complex, the safranin is able to stain the thin peptidoglycan
layer underneath, causing the bacteria to appear pink. The pink bacteria
can then be identified as Gram neg. -ANSWER✔✔What is the counter
stain that is used alongside Gram stain to identify the Gram neg bacteria?
How does this work?
Cells from a culture are taken and spread over a thin area of a slide and
then heat fixed. The smear doesn't need to be too thin or too thick,
otherwise it will be unable to be read properly. Smears are heat fixed using
a bunsen burner, an electric incinerator, or methanol. This is done to kill
the bacteria on the slide, prevent bacteria from washing off the slide, and
allowing the smear to take up stain better. -ANSWER✔✔What is smear?
)
, QUESTIONS AND ANSWERS WITH COMPLETE SOLUTIONS lOMoARcPSD| 69811638
What is important when preparing a smear? How are smears heat fixed
and why?
Place the slide on a staining rack and cover the smear with crystal violet
solution. Let stand for 30-60 seconds. Rinse with tap water to remove the
crystal violet, then shake off excess water. Cover the smear with Gram's
iodine and let stand for 30-60 seconds. Rinse with water, then shale off
excess. Decolorize the smear with acetone-alcohol and rinse with water as
soon as the purple/blue color no longer runs off the slide. *Be careful to
not over or under decolorize* Shake off excess water and counterstain
with safranin for 30 seconds, rinse with water, and dry slide by air or by
blotting. -ANSWER✔✔What is the Gram staining procedure?
Gram neg cells such as human cells will appear washed out and gram pos
bacteria will appear gram neg or partially stained. Gram neg cells such as
human cells will appear dark red / purple and other gram neg bacteria
appear gram pos. -ANSWER✔✔What will happen is the decolorizer is left
on too long? What about under-decolorized?
Damaged cells are a potential problem when looking at older culture, they
will not take up stain. This can be due to antibiotics. Overheating a slide
distorts cells from their normal shape, causing them to look weird when
viewing. Improper reagent use can be a source of error when one is
omitted or they are used in the wrong order. Excessive rinsing can wash
out the crystal violet or crystal violent iodine complex away, Prolonged
counterstaining might cause the crystal violet complex to be leached from
the Gram pos MOs. -ANSWER✔✔How will damaged cells pose as a
source of error when staining? How does overheating a slide pose as a
source of error? What about improper reagent use? What about excessive
rinsing and prolonged counterstaining?
Media is used to culture specimens, isolate bacteria, biochemicals used for
identification, and used for antibiotic susceptibility.
Liquid broth, semi-solid agar (0.3-0.5%), agar slants, and solid agar (1-
2%). Polysaccharide is the main component, melting at 100 C and staying
liquid until 45-50 C. Different agars are created by using different
amounts of polysaccharide. Semi-solid has less, whereas solid has more. -
)
