Microbio Final

Front 1

1. Mannitol SaltAgar (MSA) is both selective and differential, used for ...?

Back 1

isolation and diff. of S. aureus

Front 2

___ provides the substrate for fermentation and makesthe medium differential.

Back 2

Mannitol

Front 3

___makes the medium selective due to the highconcentration.

Back 3

sodium chloride, salt

Front 4

Name one chemical that can be used to inhibit Gram (+) bacteria.

Back 4

Bile salts, crystal violet

Front 5

Name one chemical that can be used to inhibit Gram (–) bacteria.

Back 5

Phenylethyl alcohol (PEA)

Front 6

Name one type of media that can select for Gram-positiveorganisms.

Back 6

MannitolSalt Agar (MSA)

Front 7

Name one type of media that can select for Gram-negative organisms.

Back 7

EosinMethylene Blue

Front 8

Hektoen Enteric Agar is used to isolate two different species of bacteria that produce blue-green colored growth on the plate. Name one of these species.

Back 8

Salmonella,Shigella

Front 9

What is the proper way to incubate an agar plate?

Back 9

upside down

Front 10

When microorganisms ferment lactose or another sugar, they produce what substance that changes the pH? (Many differential media have indicators that change color as a result.)

Back 10

lactic acid

Front 11

What is the purpose of a Durham tube (used in the Phenol red media)?

Back 11

To see if thebacteria produces a gas

Front 12

Name one type of media that can be used to determine the ability of the organism to ferment carbohydrates.

Back 12

Phenol Red Broth

Front 13

The MR test is designed to detect organisms capable of performing

Back 13

mixed acid fermentation

Front 14

___ converts hydrogen peroxide into water and gaseous oxygen.

Back 14

Catalase

Front 15

If during the oxidase test the reagent changes color, it indicates that ___ is present.

Back 15

cytochrome c oxidase

Front 16

A nitrate test turns red if:

a. Nitrate is reduced to nitrite (positive)

b. Nitrate is not reduced (negative)

c. Both A & B, depending on which reagents have been added

d. Neither A or B, the nitrate test does not turn red

Back 16

a. Nitrate isreduced to nitrite (positive)

Front 17

True or False:If no color change takes place with the addition of nitrate reagent A and nitrate reagent B to the inoculated nitrate broth, then the organism cannot reduce nitrate.

Back 17

False

Front 18

___ removes the amine (NH2) group from the amino acid phenylalanine.

Back 18

Deamination

Front 19

What color indicates a positive phenylalanine deaminase test?

Back 19

Green

Front 20

If the Simmons Citrate slant changes color after inoculation and incubation, it indicates that ___is present.

Back 20

citrate permease

Front 21

True or False: If a color change takes place with the addition of nitrate reagent A, nitrate reagent B, and zinc to the inoculated nitrate broth, then the organism cannot reduce nitrate.

Back 21

True

Front 22

Extracellular enzymes are produced by some bacteria in order to hydrolyze (break down)molecules in starch agar, milk agar, and nutrient gelatin. Why do the bacteria need to hydrolyze the molecules?

Back 22

To take up the nutrients from the agar

Front 23

The ability of an organism to hydrolyze starch is due to the presence of the enzyme ___

Back 23

amylase

Front 24

Hydrogen sulfide (H2S) gas may be produced when sulfur is reduced. What indicates the presence of hydrogen sulfide in SIM media or TSIA media?

Back 24

Black color

Front 25

Name one of the three bacterial activities that can be determined with SIM medium.

Back 25

Sulfur reduction

Front 26

If a TSI slant undergoes reversion so that a red slant and a yellow butt is observed after 24hours what does that indicate?

Back 26

Only glucose is fermented

Front 27

Name two of the four basic reactions that can occur in litmus milk.

Back 27

Lactose fermentation, reduction of litmus

Front 28

The ability of an organism to hydrolyze milk protein is due to the presence of the enzyme

Back 28

casease

Front 29

Name one of the two enzymes responsible for starch hydrolysis.

Back 29

Amylase

Front 30

What result in a urease broth indicates the organism performs rapid urease production?

Back 30

Pink

Front 31

___ hemolysis is the complete destruction of RBCs and hemoglobin on a blood agar plate and is indicated by complete clearing of the medium around the colonies.

Back 31

β

Front 32

Streptolysin __ isoxygen-labile and expresses maximal activity under anaerobic conditions.

Back 32

O

Front 33

Snyder test medium is formulated to favor the growth of oral bacteria while discouraging the growth of other bacteria. How is this accomplished?

Back 33

thepH of the medium is 4.8 (acidic) and glucose is added as a fermentablecarbohydrate - lactobacilli and streptococci survive these harsh conditions,ferment the glucose, and lower the pH even further (green --> yellow)

Front 34

If Snyder agar turns yellow after 48 hours of incubation, it indicates ___ susceptibility to dental caries.

Back 34

moderate

Front 35

___ -hemolysis is the partial destruction of RBCs and hemoglobin on a blood agar plate and is indicated by a greenish coloring of the medium around the colonies.

Back 35

α

Front 36

Streptolysin ___ is oxygen-stable and expresses maximal activity under anaerobic conditions.

Back 36

S

Front 37

What does OCD stand for in relation to urine culture?

Back 37

Original cell density

Front 38

CFU/loop volume = OCD, 63/0.001mL = 6.3 x 10^4Calculate the OCD of a urine culture if 63 colonies are counted on a plate inoculated with a0.001 mL loop. Be sure to include units and use scientific notation.

Back 38

CFU/loop volume = OCD, 63/0.001mL = 6.3 x 10^4

Front 39

Calculate the OCD of a urine culture if 58 colonies are counted on a plate inoculated with a 10mLloop. Be sure to include units and use scientific notation.

Back 39

Add a zero to the front of # mL to convert to mL. i.e. 10mL = .010mL