Lab test 3 Flashcards
(48 cards)
Durham Tube Sugar Fermentation purpose?
does the bacteria ferment sugar
What is the color of the Durham Tube Sugar Fermentation?
Red media with a tube in it.
What is the indication of a positive test for the Durham Tube Sugar Fermentation
yellow color or a gas bubble in the inverted tube that occupies at least 10% of the tube
Purpose of the catalase production test
does the bacteria produce the enzyme catalase
What type of media is used for the catalase production test?
TSA plate
what is the regeant of the catalase reaction?
hydrogen peroxided. catalase turns hydrogen peroxide into water and oxygen
what does the yellow color indicate in the Durham Tube test?
yellow indicates the production of acid
what indication do you get when catalase production is positive?
once you add hydrogen peroxide the culture will bubble indicating the production of oxygen gas.
which media is used in oxidase production?
TSA plate
what does the oxidase production test for?
the production of cytochrome oxidase. which differentiates bacteria that have cytochrome oxidase and use oxygen as a terminal electron acceptor and those that can use oxygen as the final electron acceptor but have other types of oxidase.
What is cytochrome oxidase?
it is an enzyme in the electron transport chain. this enzyme catalyzes the transfer of electrons from reduced cytochrome c to molecular oxygen.
for the oxidase production test, what is a positive result?
purple color
in the oxidase production test what indicates a negative result?
yellow color
what does the nitrate reduction test test for?
tests the ability of a bacteria to use nitrate as a final electron acceptor.
in the nitrate reduction test what is the reagent?
Trommsodorf solution and 1 drop H2SO4 dilute.
After adding Trommsdorf solution and H2SO4 dilute to a nitrate reduction test what indication do you get if the test is positive and what does a positive test mean?
If the mixture turns blue then the test is positive. this means that nitrite is present and that nitrate has been reduced to nitrite.
In nitrite reduction test if the solution does not turn blue after adding Trommsdorf solution and H2SO4 what do you do next?
Add diphenylamine and two drops of H2SO4.
After adding diphenylamine and two drops of H2SO4 what is the indication of a positive test?
If the solution does not turn blue then the test is positive meaning that nitrate has been converted to nitric oxide, gaseous nitrogen, or ammonium which does not require nitrate reductase
What enzyme does the nitrate reduction test for
nitrate reductase
What does the mixed acid and Butanediol Production test test for?
it determines other end products of fermentation.
What is the medium used for the mixed acid and Butanediol Production test?
Methyl Red-Voges Proskauer (MR-VP) which is a medium of glucose broth that b
what does the starch hydrolysis test for?
production of amylase
what does amylase do?
it breaks down starch into maltose, glucose, and dextrins.
What medium is used for the starch hydrolysis test?
starch agar plate
