Question

in the oxidase test, what does a purple color indicate?
nitrate reduction
presence of catalase
presence of cytochrome c oxidase
acid production
question 4 (1 point)
in the gelatin hydrolysis test, a liquid medium after chilling indicates:
protein denaturation only
ph change
negative result
gelatinase positive

Explanation:

• Oxidase test: The oxidase test is used to determine if an organism produces cytochrome c oxidase. When cytochrome c oxidase is present, it reacts with the oxidase reagent (e.g., tetramethyl - p - phenylenediamine dihydrochloride) to form a purple - colored compound (indophenol).
• Gelatin hydrolysis test: Gelatin is a protein. Gelatinase is an enzyme that hydrolyzes gelatin. When gelatin is hydrolyzed, it cannot solidify (gel) upon chilling. A liquid medium after chilling indicates that gelatin has been hydrolyzed, which means the organism is gelatinase - positive.

Answer:

• For the oxidase test question: Presence of cytochrome c oxidase.
• For the gelatin hydrolysis test question: Gelatinase positive.