Starch Digestion and Salivary Amylase Quiz
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Questions and Answers

What is formed when phosphoric acid reacts with ammonium molybdate in the presence of HNO3?

  • A white precipitate
  • A red solution
  • A yellow precipitate (correct)
  • No precipitate forms

    • What occurs when KSCN is added to saliva and mixed with FeCl3 and HCl?

  • A blue precipitate forms
  • A colorless solution forms
  • No visible reaction occurs
  • A brick-red precipitate appears (correct)

    • What is the concentration range of SCN- ions found in saliva?

  • 0.01-0.03 mg% (correct)
  • 0.05-0.10 mg%
  • 0.50-1.00 mg%
  • 0.20-0.30 mg%

    • How does the concentration of KSCN in smokers' saliva compare to that in non-smokers' saliva?

    <p>It is higher in smokers</p> Signup and view all the answers

    What product results from the proteic metabolism as indicated in the content?

    <p>SCN- ions</p> Signup and view all the answers

    What is the final digestion product of starch?

    <p>Maltose</p> Signup and view all the answers

    Which color indicates the presence of amylodextrines after adding Lugol solution?

    <p>Blue-violet</p> Signup and view all the answers

    What temperature condition affects the activity of salivary amylase the most?

    <p>Boiling temperature</p> Signup and view all the answers

    Which statement describes the effect of boiled saliva on starch digestion?

    <p>It has no effect on the starch solution.</p> Signup and view all the answers

    What is observed after 30 minutes of starch digestion with fresh saliva?

    <p>Colorless solution</p> Signup and view all the answers

    Which reagent is used to identify maltose in the digestion process?

    <p>Trommer reagent</p> Signup and view all the answers

    What color does erythrodextrines produce when reacting with Lugol solution?

    <p>Pink-violet</p> Signup and view all the answers

    What is the primary factor that influences salivary amylase activity?

    <p>Temperature and pH</p> Signup and view all the answers

    What is the primary role of NaOH in the Trommer reaction with maltose?

    <p>To maintain an alkaline environment</p> Signup and view all the answers

    What indicates the presence of calcium ions in saliva when treated with ammonium oxalate?

    <p>White insoluble precipitate formation</p> Signup and view all the answers

    What is observed when maltose is reacted with CuSO4 solution in an alkaline pH during the Trommer reaction?

    <p>Development of a red-copper precipitate</p> Signup and view all the answers

    Which of the following statements about phosphorus detection in saliva is correct?

    <p>It involves the use of HNO3 and ammonium molybdate</p> Signup and view all the answers

    Why is boiling necessary during the Trommer reaction?

    <p>To promote the formation of precipitates</p> Signup and view all the answers

    What type of crystals is associated with the presence of calcium oxalate precipitates in saliva?

    <p>Octahedral crystals</p> Signup and view all the answers

    What might be a cause for a negative Trommer reaction when testing maltose?

    <p>Test conducted in a neutral pH</p> Signup and view all the answers

    Which component is critical for the precipitation of phospho ammonium molybdate in saliva testing?

    <p>HNO3</p> Signup and view all the answers

    Study Notes

    Digestive Effect of Saliva on Starch

    • Starch digestion begins in the mouth, mixing with saliva containing ptyalin.
    • Starch breaks down into shorter polysaccharides (amylodextrins, erythrodextrines, acrodextrines), and finally maltose (a disaccharide).
    • Each step can be identified using Lugol's solution (identification reaction).
    • The final product of starch digestion is maltose, identifiable using the Trommer reaction.
    • Objective: Understand salivary amylase action, its demonstration, and factors influencing its activity (temperature, pH).

    Materials

    • 1% Starch solution
    • 1% Iodine (Lugol's reagent) (1:2:300 iodine, potassium, water)
    • Test tubes
    • Graduated cylinders
    • Saliva
    • Sodium hydroxide (NaOH)
    • Copper(II) sulfate (CuSO4) 10% solution
    • Filter paper

    Procedure

    • Use clean test tubes, adding 5ml of starch solution and 2-3 drops of Lugol's solution (control).
    • Experiment with saliva: boiled saliva (T2), fresh saliva (T3), fresh saliva, 5-7 min, then heat (T4), fresh saliva, 15-20 min, then heat (T5) and fresh saliva, 30 minutes (T6).
    • Observe color changes at each stage of starch digestion:
      • Amylodextrines: blue-violet (T3)
      • Erythrodextrines: pink-violet (T4)
      • Acrodextrines: colourless (T5)
      • Maltose: colourless (T6)

    Trommer Reaction

    • Principle: Maltose reduces Copper(II) sulfate (CuSO4) to cuprous oxide in alkaline conditions.
    • Materials: Test tubes, Bunsen burner, NaOH 20% solution, CuSO4 10% solution, starch solution.
    • Procedure: Mix maltose solution and NaOH, add CuSO4 solution dropwise, generating a blue precipitate. Boil the solution to form a red-colored copper precipitate.

    Calcium in Saliva

    • Materials: Test tube, ammonium oxalate 10% solution, saliva, microscope
    • Procedure: Add ammonium oxalate to saliva, forming a white precipitate in the presence of calcium. Examine octahedral crystals under a microscope (related to calcium oxalate formation).

    Phosphorus in Saliva

    • Materials: Test tubes, gas burner, HNO3 (nitric acid), (NH4)2MoO4 (ammonium molybdate)
    • Procedure: Add HNO3 and ammonium molybdate to saliva. Heat carefully. Formation of a yellow precipitate indicates phosphorus (phospho ammonium molybdate).

    Potassium Thiocyanate in Saliva

    • Materials: Test tubes, FeCl3 (ferric chloride) 3%, HCl (hydrochloric acid) 10% solution, saliva
    • Procedure: Add HCl and ferric chloride to saliva. A brick-red precipitate of ferric thiocyanate indicates the presence of potassium thiocyanate. Higher levels of thiocyanate are found in the saliva of smokers.

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    Related Documents

    Digestive Effect of Saliva on Starch PDF

    Description

    This quiz explores the digestive effect of saliva on starch, detailing the biochemical processes involved when starch interacts with salivary amylase. It covers the identification of starch digestion products and the factors impacting enzyme activity. Students will test their understanding of these concepts through a series of questions based on experimental procedures and outcomes.

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