Term | Definition |
What are the three different carbs tested for in the Phenol Red Broth test? | Glucose, Lactose, and Sucrose. |
How to interpret the results of a Phenol Red Broth test (card 1 of 2) | Yellow broth with bubble in tube = Fermentation with acid and gad end products
Yellow broth with no bubble in tube = Fermentation with acid end products but no gas |
How to interpret the results of a Phenol Red Broth test (card 2 of 2) | Red Broth with no bubble in tube = No fermentation
Pink Broth with no bubble in tube = Degradation of peptone, alkaline end products |
Which enzymes must microbes produce to break down either lactose or sucrose? | To break down lactose - B-galctosidase
To break down sucrose - Sucrase |
What is Methyl Red Used for? | Detecting whether or not an organism can conduct mixed acid fermentation |
What is Voges-Proskauer used for? | Detecting organisms that utilize butylene glycol to produce acetoin |
What are some examples of mixed acid fermentation byproducts? | Lactic Acid
Acetic Acid
Formic Acid |
What reagents used to produce a color change in a methyl red test? | Methyl Red |
What reagents are used to produce a color change in a Voges-Proskauer test? | Barritt’s A and Barritt’s B reagent |
How do you interpret the results of a methyl red test? | Red result means positive for mixed acid fermentation, no color change means no mixed acid fermentation |
How do you interpret the results of a Voges-Proskauer test? | Red result means acetoin production, no color change means no acetoin has been produced |
What is the purpose of a citrate test? | To find out whether or not an organism can utilize citrate as a carbon source |
What reagent is used in a citrate test and what are the byproducts? | Reagent - Sodium citrate, has byproducts oxaloacetate & pyruvate. |
What is an oxidase test used for? | Oxidase is used to identify organisms that produce the enzyme cytochrome oxidase. |
What is a catalse test used for? | Catalase is used to identify cells that can break down hydrogen peroxide into H2O and O2. |
In a positive oxidase test what enzymes are produced? | A positive oxidase test produces cytochrome oxidase. |
In a positive catalase taste what enzymes are produced? | A positive catalase test produces catalase. |
What is the cytochrome oxidase enzyme used for? | Cytochrome oxidase is used in the electron transport chain as a donor transfer electrons to oxygen |
What is the catalase enzyme used for? | Catalase is used to get rid of peroxide in an O2 environment |
What does a positive catalase test look like? | A positive catalase test produces bubbles because of the evolution of O2 gas. |
How is a positive oxidase reaction determined? | A positive oxidase reaction will turn blue or purple within 15 seconds |
How is a positive catalase reaction determined? | A positive catalase reaction is determined by bubbling. |
What does a positive oxidase test look like? | An oxidase positive will turn violet to purple immediately or within 10 to 30 seconds. Delayed reactions should be ignored. |