Unknown Cultures Flashcards
(41 cards)
physiological tests detect the…
products of enzymatic reactions
a “positive” test indicates that the
enzyme is made by the organism
Catalase Test
tested for:
positive test:
negative test:
- catalase enzyme
- bubbles when peroxide is added
- no change when peroxide is added
Oxidase Test
tested for:
positive test:
negative test:
- presence of cytochrome oxidase
- blue color when oxidase reagent is added
- no color change
what test has a time limit of 30 secs- 1 min?
the oxidase test
which medium contains sodium thioglycollate? why is this significant?
FTM
b/c it keeps O2 levels low
in an FTM tube where is oxygen absent?
at the bottom of the tube
what is used for carbohydrate fermentation?
4 tubes
- glucose
- lactose
- sucrose
- mannitol
carbohydrate fermentation produces
acid and/or gas
in carbohydrate fermentation the test tubes contain….
- a durham tube
- an indicator
what is the indicator found in the test tubes for carbohydrate fermentation? what color changes indicate acid and alkaline condition?
phenol red
- acid: yellow
- alkaline: pink
citrate slants contain
- citrate
- bromophenol blue indicator
Citrate Test
tested for:
positive test:
negative test:
- citrate
- bright blue
- green
blue at alkaline pH
green at neutral pH
Startch Hydrolysis
tested for:
positive test:
negative test:
- enzyme amylase
- zone of clearing after addition of grams iodine
- no zone of clearing
function of amylase
cleave strach into glucose
Hemolysis Test
tested for:
positive test:
negative test:
- hemolysin
- zone of clearing
- no zone of clearing
beta-hemolysis indicates
complete clearing of blood around colonies
alpha-hemolyisis indicates
partical clearing of blood around colonies
gamam-hemolysis indicates
no hemolysis at all
BAP is
TSA containing 5% sheeps blood
Urea Hydrolysis
tested for:
positive test:
negative test:
- urease
- hot pink
- yellow-orange
yellow-organge is the initial color so a negative result would be no color change
Nitrate Reduction Test
tested for:
positive test:
negative test:
- reduction of nitrate(NO3) to nitrite (NO2)
- dark pink-red
- no color change
confirming the nitrate reduction test
tested for:
positive test:
negative test:
- nitrate reduction
- no color change after zinc addition
- dark pink-red after zinc addition
why does the nitrate reduction test need to be confirmed?
b/c some cells convert nitrite into other molecules such as N2 and NH3
