Microbiology Lab Final

Question 1

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)

Answer 1

Gram - positive rods (bacilli)

Question 2

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

Answer 2

Clostridium tetani
A

Clostridium botulinum
B

Clostridium perfingens
D

Bacillus cereus
C

Question 3

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

Answer 3

B

Question 4

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

Answer 4

D

Question 5

The purpose of bacterial endospore formation is reproduction.

True

False

Answer 5

F

Question 6

Only a fraction (the estimate is 10%) of bacteria that exist in the environment can be grown in the lab.

True
False

Answer 6

T

Question 7

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

Answer 7

A

Question 9

Describe staphylococci

Answer 9

Spherical with some clumping (Question 2 on pre lab 2 quiz)

Question 10

Which of the following describes a vibrio

rod
curved rod
spiral
sphere

Answer 10

curved rod

Question 10

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

Answer 10

D

Question 11

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

Answer 11

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

Question 12

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

Answer 12

B

Question 13

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

Answer 13

A

Question 14

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

Answer 14

C

Question 15

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

Answer 15

D

Question 16

What is the most common etiologic agent that causes urinary tract infections?

A. Proteus vulgaris
B. Neisseria gonorrhoeae
C. Escherichia coli
D. Staphylococcus aureus

Answer 16

C

Question 17

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

Answer 17

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

Question 18

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

Answer 18

T

Question 19

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

Answer 19

B

Question 20

Capsules (distinctly shaped glycocalyces) consist primarily of _________________.

A. carbohydrates
B. lipids
C. proteins
D. peptidoglycan

Answer 20

A

Question 21

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

Answer 21

Greenish appearance around colonies - C. Alpha hemolysis

No color change around colonies - A. Gamma hypolysis

Yellowish (clear) appearance around colonies - B. Beta hemolysis

Question 22

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

Answer 22

Streptococcus pneumonia = a

Streptococcus pyogenes = b

Question 23

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.

Answer 23

A

Question 24

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

Answer 24

A

Question 25

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.

Answer 25

B

Question 26

Antibiotics target specific pathogens. True False

Answer 26

F

Question 27

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.

Answer 27

B

Question 28

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

Answer 28

D

Question 29

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.

Answer 29

C

Question 30

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

Answer 30

1 and 2

Question 31

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.

Answer 31

A

Question 32

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

Answer 32

2 and 4

Question 33

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

Answer 33

B and C

Question 34

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

Answer 34

Trychophyton - Cutaneous mycosis Sporothrix - Subcutaneous mycosis Histoplasmosis - systemic mycosis Epidermophyton - cutaneous mycosis Coccidioidomycosis - systemic mycosis Black piedra - superficial mycosis

Question 35

After a first time exposure to a pathogenic virus or bacterium, which antibody appears first in the serum? IgG IgE IgA IgM IgD

Answer 35

IgM

Question 36

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.

Answer 36

A

Question 37

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

Answer 37

B

Question 38

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

Answer 38

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

Question 39

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.

Answer 39

B

Question 40

Antibodies are _____________________. nucleic acids. lipids. carbohydrates. proteins

Answer 40

Proteins