Questions and Answers
What happens to coagulable proteins when heated at their isoelectric pH?
Which of the following statements is true regarding proteins and their interaction with acids?
What role do weak bonds play in the denaturation of proteins during heating?
What is the expected outcome of heating gelatin in the heat coagulation test?
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Why do proteins have a net zero charge at their isoelectric pH?
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What effect does heating have on polypeptides, which are non-coagulable proteins?
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What primarily determines the coagulation of proteins during the heat coagulation test?
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Which type of protein is expected to show a dense coagulum during the test?
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What is required to precipitate proteins like albumin according to the procedure described?
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What indicates the presence of protein in the xanthoproteic test?
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During the procedure, how is the acrimony of HNO3 categorized?
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What role does 1% acetic acid play in the protein precipitation process?
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What should be done after adding concentrated HNO3 to the test tubes?
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What is the expected outcome after heating the top half of the test tube in the xanthoproteic test?
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Which amino acids are specifically detected through the xanthoproteic test?
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What is the purpose of cooling the test tubes under tap water before observation?
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What is the primary use of the xanthoproteic test?
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What is the expected color change when alkali is added to the nitro derivatives formed in the xanthoproteic test?
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Which chemical is primarily used to form the nitro derivatives in the xanthoproteic test?
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What type of amino acids gives a positive result in the xanthoproteic test?
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What is a potential consequence of heating coagulable protein at isoelectric pH?
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Which material is NOT listed as part of the xanthoproteic test setup?
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In preparing a 40% NaOH solution, what is the total volume of solution obtained from dissolving 40 gm of NaOH in distilled water?
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Which of the following amino acids is identified through the xanthoproteic test?
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What chemical reaction is primarily responsible for the development of a green color in Fouchet's test?
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Which reagent is used to precipitate sulfate radicals present in urine during Fouchet's test?
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What is the significance of the green color formation in urine testing?
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What role does trichloroacetic acid (TCA) play in the detection of bilirubin in urine?
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In the context of the described case, what condition might the 4-day old premature infant be suffering from?
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Which component of Fouchet's reagent is responsible for the oxidation of bilirubin?
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What initial step is taken in the procedure for performing Fouchet's test?
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What is the primary substance that adheres to the barium sulfate precipitate in the context of these tests?
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What substance is primarily detected through Fouchet's test?
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Which of the following components is NOT part of Fouchet’s reagent?
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What color indicates a positive result for bile pigments in Fouchet's test?
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Which of the following diseases is associated with increased bilirubin in urine?
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In the context of Fouchet's test, how is protein affected when heated in an acidic medium?
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Which of the following can be used as an alternative to Fouchet's solution in the test?
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Which abnormal constituent of urine is primarily tested for using Fouchet's test?
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What role does barium chloride play in the materials listed for Fouchet's test?
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Study Notes
Xanthoproteic Test
- Detects aromatic amino acids: Tyrosine and Tryptophan.
- Materials Needed: Bunsen burner, 2 test tubes, distilled water, concentrated HNO3, and 40% NaOH solution.
- Principle: Upon heating amino acids with concentrated HNO3, yellow nitro derivatives form, indicating the presence of tyrosine and tryptophan.
- Differentiates aromatic amino acids from non-aromatic ones based on positive results.
- Yellow color observed confirms protein presence.
Method for Xanthoproteic Test
- Mix 1 mL test solution in one test tube, and add 1 mL distilled water in another.
- Add 1 mL concentrated HNO3 to both tubes and heat for 1-2 minutes.
- Cool and add 1 mL of 40% NaOH; observe color change: yellow indicates the presence of proteins.
Heat Coagulation Test
- Determines presence of proteins in a solution.
- Materials: 1% acetic acid diluted in distilled water, test tube, Bunsen burner.
- Principle: Coagulable proteins denature and form a coagulum at their isoelectric point (pI).
- Heating proteins in an acidic medium leads to bond breaking and uncoiling of polypeptide chains, resulting in an insoluble mass.
- No coagulation indicates non-coagulable proteins like gelatin or proteases.
Fouchet’s Test
- Detects bile pigments, primarily bilirubin and biliverdin, in urine.
- Materials: Fouchet’s reagent, fresh urine, 10% barium chloride, and filter paper.
- Principle: Ferric chloride oxidizes bilirubin to green biliverdin, producing a green precipitate.
- Green color indicates the presence of conjugated bilirubin, confirming bile pigments in urine.
- Increased urinary bilirubin levels can indicate conditions like obstructive or hepatocellular jaundice.
Method for Fouchet’s Test
- Add 5 mL of fresh urine to a test tube, mix with 2.5 mL of 10% barium chloride until a precipitate forms.
- The development of a green color signals the presence of bile pigments, suggesting possible bilirubin-related disorders.
Case Study Context
- A premature infant presented with yellowish skin discoloration, likely linked to bilirubin levels, necessitating the use of Fouchet’s test for further evaluation.
- Patient history includes a birth weight of 1.9 kg, Apgar score recorded, and administered vaccinations.
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Description
This quiz focuses on the Xanthoproteic test, specifically aimed at detecting aromatic amino acids like Tyrosine and Tryptophan. It covers the materials required and the procedural steps involved in conducting the test. Test your knowledge on this important biochemical reaction and its significance in amino acid analysis.