lab 8

Question 1

What is a gelatin test?

Answer 1

it tests for PATHOGENICITY of bacteria and if bacteria have enzyme gelatinase present.

Question 2

What does positive gelatin test indicate?

Answer 2

liquified

Question 3

what does negative gelatin test mean?

Answer 3

solid

Question 4

What does catalase test do?

Answer 4

-checks for catase.
If oxygen is reduced, the production of superoxide radical can occur.
CATALASE destroys radicals.

Question 5

Positive catalase =

Answer 5

bubbles

Question 6

negative catalase =

Answer 6

no bubbles

Question 7

What does coagulase test do?

Answer 7

coagulase is present if bacteria can form a clot around themselves for protection. Positive test is CLOTTING.

Question 8

What does DNase test do?

Answer 8

DNase can degrade a host’s DNA and show PATHOGENICITY of bacteria.

Question 9

what does positive test for DNase indicate ?

Answer 9

clear zone around colony

Question 10

What is oxidase test for?

Answer 10

-If oxidase enzyme is present as significant for energy production. used in ETC

Question 11

what is positive test for oxidase ?

Answer 11

purple color

Question 12

negative test for oxidase ?

Answer 12

light pink

Question 13

What is urease test for?

Answer 13

to break down urea and in forming ammonia. Ammonia causes rise in pH.

Question 14

positive test for urease is

Answer 14

pink/purple color

Question 15

negative test for urease is

Answer 15

yellow/green color

Question 16

what is cysteine test for ?

Answer 16

to identify is cysteine desulfurase is present. sulfur will be removed and H2S gas present

Question 17

what is positive result of cysteine test ?

Answer 17

black precipitate

Question 18

what is negative result of cysteine test ?

Answer 18

no precipitate

Question 19

Phenylalanine Deamination Test

Answer 19

Checks for phenylalanine deaminase and presence of pyruvic acid.
-adding ferric chloride to test if present

Question 20

Positive Phenylalanine Deamination Test indicates ..

Answer 20

green color

Question 21

negative Phenylalanine Deamination Test indicates

Answer 21

yellow

Question 22

What is nitrate reduction test?

Answer 22

to check for nitrate reductase
PRODUCT NEEDS TO BE NITRITE

Question 23

What indicates if nitrite is present ?

Answer 23

IF REDUCES
with addition of sulfanilic acid and dimethyl naphthylamine- the ions produce a red color change

Question 24

What if no color change?

Answer 24

No reaction occurred or may been reduced by another ENZYME

Question 25

How to make sure if nitrate reductase is present?

Answer 25

an addition of zinc

Question 26

If the addition of zinc shows color change, does it mean nitrate reductase was present in bacteria ?

Answer 26

NO it was not present in bacteria

Question 27

If no color change happens after addition of zinc, what does it mean ?

Answer 27

the bacteria already reduced the nitrate

Question 28

What is Decarboxylation of lysine ?

Answer 28

cadaverine

Question 29

what is Decarboxylation of ornithine?

Answer 29

putrescine

Question 30

what is positive result for Lysine and Ornithine Test?

Answer 30

a purple color

Question 31

What is the TDA test (Tryptophan Deaminase)?

Answer 31

Checks if bacteria can deaminate tryptophan to make indole pyruvic acid.

Question 32

What is positive result for TDA?

Answer 32

red/brown

Question 33

What type of bacteria does the API 20 system identify?

Answer 33

Enterobacteriaceae (gram -)

Question 34

Which are the mineral oils used for API test ?

Answer 34

ADH, LDC, ODC, H2S, and URE

Question 35

What is citrate utilization ?

Answer 35

using citrate as a carbon source to use the enzyme citrase. TRANSPORT Citrate into cell. BLUE INDICATOR