Exercise 5-5: Oxidation Test

4. If you observe a purple color after 1 minute, this is considered a positive result. a. True b. False

b. False (supposed to be after 20 seconds)

6. Explain the reaction that gives the purple color. (2)

The oxidase test detects the presence of a cytochrome oxidase system that will catalyse the transport of electrons between electron donors in the bacteria and a redox dye- tetramethyl-p-phenylene-diamine. The dye is reduced to deep purple color.

5. A positive result (purple color within 20 sec) indicates that the bacterium has the enzyme ________________

Cytochrome C oxidase

1. Oxidase test is used to identify bacteria containing the respiratory enzyme a. Catalase b. Cytochrome C oxidase c. Superoxide dismutase d. Cytochrome b oxidase e. Cytochrome o oxidase

b. Cytochrome C oxidase

3.) What reagent is included in the dry slide to detect the positive color reaction? a. Nitrate reagent A and B b. Ferric chloride c. Oxidase reagent d. Zinc powder e. Methyl red f. VP reagent A g. VP reagent B

c. Oxidase reagent