Microbiology Lab Final Flashcards
The bacteria of medically relevant genera that are capable of producing endospores are _________________.
Gram-positive rods (bacilli)
Gram-positive spheres (cocci)
Gram-negative rods (bacilli)
Gram-negative spheres (cocci)
Gram - positive rods (bacilli)
Match the bacterial species with the correct condition.
Clostridium tetani
Clostridium botulinum
Clostridium perfingens
Bacillus cereus
A. Lockjaw
B. Gastro-intestinal infection
C. Food poisoning
D. Gas gangrene
Clostridium tetani
A
Clostridium botulinum
B
Clostridium perfingens
D
Bacillus cereus
C
Which of the following is NOT a difference when observing bacteria in a wet mount versus a stained smear?
A. Visibility of motility
B. Distinguishable shapes and arrangments
C. Amount of light used to make bacteria visible
D. Highest possible order of magnification
B
What determines whether to use the direct or the indirect method to check for the presence of microorganisms?
A. Whether the object is indoors or outdoors
B. The number of expected microorganisms
C. Whether there are fungi or bacteria
Correct!
D. The size of the object tested
D
The purpose of bacterial endospore formation is reproduction.
True
False
F
Only a fraction (the estimate is 10%) of bacteria that exist in the environment can be grown in the lab.
True
False
T
Which of the following is NOT a factor that exacerbates the rapid transmission of infections?
A. whether it is bacterial, viral or fungal
B. global travel
C. climate change
D. urbanization
A
Describe staphylococci
Spherical with some clumping (Question 2 on pre lab 2 quiz)
Which of the following describes a vibrio
rod
curved rod
spiral
sphere
curved rod
Which of the following statement about the clinical significance of the Gram stain is INCORRECT?
A. The majority of Gram-positive infections can be successfully treated with penicillin.
B. Gram-negative bacteria are typically more sensitive to heat.
C. Gram-negative bacteria are typically more sensitive to lysis by complement.
D. Only gram-positive bacteria produce endotoxins
D
Match the stain with the correct statement.
The Gram stain
Eosin
Methylene blue
Is an example of a simple stain
Is an example of a simple stain
Is an example of a different stain
The Gram stain - is an example of a differential stain
Eosin - is an example of a simple stain
Methylene blue - is an example of a simple stain
Which of the following biochemical properties can be used to differentiate between the harmless Staphylococcus epidermidis and the pathogenic Staphylococcus aureus? Either or both of these may be present in a sample from a skin infection.
A. Lactose fermentation
B. Coagulase activity
C. Catalase activity
D. Urease activity
B
How is fermentation manifesting in identification tests using biochemical tests?
A. Color-change of pH indicator
B. Formation of black precipitate
C. Spectrophotometric measuring of turbidity
D. Bubble formation
A
What is commonly used for field testing of coli-form bacteria?
A.Coagulase test
B.Catalase test
C.MacConkey’s agar
D.Precipitate formation due to H2S formation
C
Which type of ion forms a black precipitate with sulfide, from hydrogen sulfide (H2S) produced by certain bacteria?
A. Potassium
B. Magnesium
C.Calcium
D. Iron
D
What is the most common etiologic agent that causes urinary tract infections?
A. Proteus vulgaris
B. Neisseria gonorrhoeae
C. Escherichia coli
D. Staphylococcus aureus
C
Match the correct term for the type of food poisoning:
Reaction to bacteria in contaminated food that establish themselves in the digestive tract
Reaction to toxins from bacteria that flourish in food
A. Intoxication
B. Intestinal infection
Reaction to bacteria in contaminated food that establish themselves in the digestive tract - B.Intestinal infection
Reaction to toxins from bacteria that flourish in food - A. Intoxication
Signs and symptoms of food poisoning that is due to intoxication develop faster than signs and symptoms of an intestinal tract infection due to consumption of contaminated food.
True
False
T
A patient presented with signs and symptoms of a respiratory infection. They recently returned from a 6-month humanitarian mission at a refugee camp in Southeast Asia. A Ziehl-Neelsen stain of a sputum sample revealed skinny pink rods, which would be indicative of _________.
A. leprosy
B. tuberculosis
C. pneumococcal pneumonia
D. strep throat
B
Capsules (distinctly shaped glycocalyces) consist primarily of _________________.
A. carbohydrates
B. lipids
C. proteins
D. peptidoglycan
A
Match the described appearance of the blood agar plate showing bacterial growth with the correct type of hemolysis.
Greenish appearance around colonies
No color change around colonies
Yellowish (clear) appearance around colonies
A. Gamma hypolysis
B. Beta hemolysis
C. Alpha hemolysis
Greenish appearance around colonies - C. Alpha hemolysis
No color change around colonies - A. Gamma hypolysis
Yellowish (clear) appearance around colonies - B. Beta hemolysis
Although not reliably predictable for all streptococci, two important and serious pathogens are consistent with respect to their hemolytic activity. Match the two species with the correct type of hemolysis.
Type:
a for alpha hemolytic
b for beta hemolytic
c for gamma hemolytic
Streptococcus pneumonia
Streptococcus pyogenes
Streptococcus pneumonia = a
Streptococcus pyogenes = b
The term antibiotic is used for
A. a drug that treats bacterial infections.
B. a drug that originates from a microorganism.
C. a drug used to treat microbial infections.
D. a drug that is bactericidal.
A
What effect do alcohols and detergents have on microbial cells?
A. They disrupt the cell membrane.
B. They damage various biomolecules through oxidation.
C. They lyse the cell wall.
D. They react with free sulfhydryl (-SH) groups in proteins
A
What is the effect of penicillin?
A. It inhibits DNA transcription.
B. It inhibits peptidoglycan synthesis
C. It inhibits an enzyme in the biosynthetic pathway for folic acid.
D. It inhibits ribosomes.
B
Antibiotics target specific pathogens.
True
False
F
Some fungi are dimorphic. What does that mean?
A. The can reproduce sexually or asexually.
B. They can exist as yeast or mold.
C. They can appear as yeast or pseudohyphae.
D. They belong to more than one genus.
B
Which of the following is a unique biomolecule in fungi, the biochemistry of which is the target of various antifungal drugs?
A. Lipopolysaccharides
B. Capsule polysaccharides
C. Teichoic acid
D. Ergosterol
D
What is a mycelium?
A. A fungal sexual reproductive organ.
B. A smaller cell emerging from asexual reproduction of yeast by budding.
C. A tangles mass of hyphae.
D. A subdivision in the higher fungi.
C
Which of the following fungi are commonly associated with bird guano?
Histoplasma capsulatum
Cryptococcus neoformans
Candida albicans
Sporothrix schenckii
3 and 4
1 and 4
2 and 3
1 and 2
1 and 2
Many pathogenic fungi belong to the group deuteromycetes. How does this group differ from other classes of fungi?
A. Higher fungi for which a sexual stage has never been observed.
B. Higher fungi, which produce their sexual spores in a structure called ascus.
C. These are also called phycomycetes.
D. Higher fungi, which produce their sexual spores in a structure called basidium.
A
Which of the following can cause opportunistic infections?
Histoplasma capsulatum
Candida albicans
Paracoccidioides brasiliensis
Aspergillus sp.
2 and 4
2 and 3
1 and 4
1 and 3
2 and 4
How can yeast cells be differentiated from Staphylococcus aureus?
A. Staph. aureus grows on tryptic soy agar (TSA) plates, while yeasts don’t.
B. Yeast cells are uneven in size, while Staph. aureus cells are all the same size.
C. Yeasts grow on Sabouraud’s Dextrose agar (SDA), while Staph. aureus does not.
D. Yeasts stain Gram negative and Staph. aureus cells stain Gram positive
B and C
Fungal diseases are often categorized by the location where they will grow in the host. Match the following categories (cutaneous, subcutaneous, and systemic) with the corresponding fungus.
Trychophyton
Sporothrix
Histoplasmosis
Epidermophyton
Coccidioidomycosis
Black piedra
Options:
- Cutaneous mycosis
- Subcutaneous mycosis
- Systemic mycosis
- Cutaneous mycosis
- Systemic mycosis
- Superficial mycosis
Trychophyton - Cutaneous mycosis
Sporothrix - Subcutaneous mycosis
Histoplasmosis - systemic mycosis
Epidermophyton - cutaneous mycosis
Coccidioidomycosis - systemic mycosis
Black piedra - superficial mycosis
After a first time exposure to a pathogenic virus or bacterium, which antibody appears first in the serum?
IgG
IgE
IgA
IgM
IgD
IgM
The precipitation test may lead to a false negative result, especially in the case of a serum containing a very high concentration of a specific antibody. What is the reason?
A. If the serum sample does not get diluted adequately, there is an antibody excess that does not allow for enough cross-linking for visible precipitate formation.
B. If the serum sample does not get diluted adequately, there is an antigen excess that does not allow for enough cross-linking for visible precipitate formation.
A
In the precipitation test, the so-called prozone refers to no visible precipitation
A. in the first few minutes of the test.
B. due to antibody excess at a serum dilution that is too low.
C. in the first days of an infection
B
Match the correct antibody type with the function/description. Answers can be chosen more than once or not at all.
Exclusively serves as a B-cell receptor
Appears in allergic reactions
Found in response to parasitic infections
Found in secretions, such as saliva and breast milk
Exclusively serves as a B-cell receptor - IgD
Appears in allergic reactions - IgE
Found in response to parasitic infections - IgE
Found in secretions, such as saliva and breast milk - IgA
A positive result on an ELISA test for HIV will not lead to an unequivocal diagnosis but has to be followed up by a Western blot test because
A. the Western blot is more sensitive than the ELISA test.
B. the ELISA test only assesses for one specific antibody and thus there is a chance of false positive.
C. ELISA tests for antigens, while the Western blot tests for antibodies.
D. ELISA tests for antibodies, while the Western blot tests for antigens.
B
Antibodies are _____________________.
nucleic acids.
lipids.
carbohydrates.
proteins
Proteins
