Energy-producing biochemical reactions in which organic molecules serve both as electron acceptors and donors
Why don't all microorganisms produce the same end product from pyruvate?
The end product is a characteristic of the particular microorganism
What is the purpose of carbohydrate fermentation?
To see if glucose fermented to acids or acids and gas.
What is the importance of catalase to certain bacteria?
Some bacteria contain flavoproteins that reduse oxygen, resulting in production of hydrogen peroxide
-Hydrogen peroxide is toxic to the bacteria.
-Catalase catalyzes the destruction of hydrogen peroxide
Do anaerobic bacteria require oxygen?
No, because they contain flavoproteins that produce hydrogen peroxide
What is the importance of cytochrome oxidase to bacteria that possess it?
It uses oxygen as an electron acceptor during the oxidation of reduced cytochrome c to form water and oxidized cytochrome c.
What is the function of the test reagent in the oxidase test?
It produces a color change;
If black/blue color forms, you have a positive oxidase
The oxidase test is used to differentiate among which groups of bacteria?
The bacteria that use oxygen as the final electron acceptor and those that don't. (Anaerobic and Aerobic)
Why should nichrome or other iron-contatining inoculating devices not be used in the oxidase test?
May cause a false-positive reaction
Explain the biochemistry of the urease reaction.
Urease attacks the nitrogen and carbon bond in amide compounds such as urea, forming the end products CO2 and water.
In a positive urease test, why does the urea broth or slant change color?
To show a positive test for urea hydrolysis
Why is the development of a red color a negative test when zinc is added?
Since zinc reduces nitrates to nitrites, a pink or red color will appear and verifies the fact that nitrates were not reduced to nitrites by the bacteria (a negative test).
After reagents A&B are added for the nitrate reduction test, what happens?
Produce a red color: positive nitrate reduction
Colorless: either positive or negative nitrate reduction