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The flashcards below were created by user
mikepl103
on FreezingBlue Flashcards.
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What is the enzyme catalase used for?
to protect bacteria from free radicals like hydrogen peroxide, superoxide, etc.
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what is the principle of the catalase activity test?
some bacteria produce enzyme called catalase to protect themselves from free radicals like H2O2 and superoxide
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what must one do in order to see if there is catalase acitivity within a culture?
add 3% hydrogen peroxide to the culture and if gas bubbles arise, the bacteria produce catalase
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if you add 3% h2O2 to a bacterial culture and no gas bubbles form, what does this mean?
there is no catalase activity in this culture
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What chemical reaction occurs when you add h2O2 to a culture of bacteria that produce catalase?
the H2O2 is broken down by catalase into H2O and O2.
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what is a positive test for the catalase activity test?
bubbles forming
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what do bacteria use coagulase for?
to form a fibrin clot around themselves to protect against the host's defenses
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What chemicals are anti-coagulants?
citrate and EDTA
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Citrate and EDTA are __-_____
anti-coagulants
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what is a positive test for the coagulase tesst?
clotting is present
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what is a negative test for the coagulase test?
no clotting in 4 hrs
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____ and ___ are added usually as an _____ to prevent clotting by other mechanism
citrate and EDTA are added usually as anticoagulant
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in the coagulase test, results can be determined within ___ ___
4 hrs
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what does dnase do?
dnase is an enzyme produced by some bacteria that degrades host DNA and increase the pathogenicity
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what is a positive test in DNase test?
a zone of clearing around the colony indicates +ve DNase activity
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