Microbiology Lab Practical Exam 2 2025 Questions & Answers with 100% Correct Answers | Verified

Oxidase Test - *Positive Test:* -Turns blue within 20-30 seconds *Negative Test* -No color change within thirty seconds *Reagent used:* -Oxidase What is the purpose of the oxidase test? - -The tests is used to identify bacteria containing the respiratory enzyme cytochrome c oxidase as an electron acceptor in the ETC. How is the oxidase test performed? - 1. Transfer bacterium to the paper 2. Add drops of complex A & B to bacterium 3. Observe for color change within 30 seconds Why should you read the results of the oxidase test within 30 seconds? - -The reagents of this test are unstable, therefore they may oxidize independently shortly after becoming moist. Therefore it is important to read within 30 seconds. Catalase Test - *Positive* -Visible Bubble production *Negative* -No Bubbles *Reagent Used:* -Hydrogen Peroxide