Questions and Answers
What is phenylalanine?
Amino acid building block used when bacteria make protein.
What is the point of the Phenylalanine test?
To determine which bacteria can use phenylalanine for energy.
What is phenylalanine deaminase?
It is the enzyme which some bacteria use to convert phenylalanine to phenylpyruvic acid.
What is deamination?
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What kind of medium is used in the Phenylalanine deaminase test?
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What is the indicator of the Phenylalanine deaminase test?
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What does a positive test result look like in the Phenylalanine deaminase test?
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What does a negative test result look like in the Phenylalanine deaminase test?
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What does a positive test result mean in the Phenylalanine deaminase test?
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What does a negative test result mean in the Phenylalanine deaminase test?
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How many drops of Ferric Chloride do you add to the inoculated phenylalanine slant?
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What are the steps of the Phenylalanine test?
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Study Notes
Phenylalanine Overview
- Phenylalanine is an essential amino acid used by bacteria to synthesize proteins and, in some cases, as an energy source.
Purpose of the Phenylalanine Test
- The test identifies bacteria's ability to utilize Phenylalanine for energy.
Phenylalanine Deaminase
- Phenylalanine deaminase is an enzyme that converts Phenylalanine into Phenylpyruvic acid, facilitating energy release in certain bacteria.
Deamination Process
- Deamination refers to the removal of an amino group from an amino acid, specifically converting Phenylalanine to Phenylpyruvic acid in this context.
Test Medium
- The Phenylalanine test utilizes a phenylalanine slant, which is a regular agar slant supplemented with Phenylalanine and without indicators.
Test Indicator
- Ferric Chloride serves as the reagent for indicating the presence of Phenylpyruvic acid in the test.
Positive Test Result
- A positive result is indicated by the Ferric Chloride changing to a green color after being added to the inoculated and incubated slant.
Negative Test Result
- A negative result is observed when Ferric Chloride remains yellow, indicating no Phenylpyruvic acid is present.
Interpretation of Results
- A positive result indicates the presence of Phenylpyruvic acid, confirming that the bacteria possess phenylalanine deaminase and can utilize Phenylalanine.
- A negative result signifies the absence of Phenylpyruvic acid, meaning the bacteria lack phenylalanine deaminase and cannot use Phenylalanine.
Ferric Chloride Application
- Five drops of Ferric Chloride are added to the inoculated Phenylalanine slant for the test.
Procedure Steps
- Inoculate phenylalanine agar slants with the sample in a 1:1 ratio.
- Incubate the tubes at 37°C until the next class.
- Add 5 drops of Ferric Chloride to the slant, allowing it to interact with the growth.
- Observe and document the results.
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Description
This quiz covers the essential aspects of the Phenylalanine test, including its purpose, the role of Phenylalanine deaminase, and the significance of positive test results. Understand the deamination process and how Ferric Chloride is used as an indicator for identifying bacteria's ability to utilize Phenylalanine for energy.
