Factors Affecting Enzyme Activity
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Questions and Answers

What conclusion can be drawn if the blue-black color does not fade during the experiment?

  • The iodine has been completely consumed.
  • The enzyme is no longer active and hydrolysis of starch has not occurred. (correct)
  • The enzyme is active and hydrolyzing starch.
  • The starch has been completely hydrolyzed.

    • Which factor does NOT affect enzyme activity according to the content?

  • Enzyme concentration
  • pH levels
  • Oxygen concentration (correct)
  • Substrate concentration

    • Why is it important to time each experiment when testing enzyme activity?

  • To limit the concentration of saliva used in the reaction.
  • To ensure consistent pH levels during the experiment.
  • To correlate the time required for starch disappearance with enzyme activity. (correct)
  • To ensure the experiment is conducted at room temperature.

    • What is the role of amylase in the context of the experiment?

    <p>To catalyze the hydrolysis of starch into simpler sugars.</p> Signup and view all the answers

    What would you expect to happen if the enzyme concentration is low?

    <p>The time required for starch to disappear will be longer.</p> Signup and view all the answers

    How does temperature affect enzyme activity based on the provided information?

    <p>Optimal temperature ranges enhance enzyme activity.</p> Signup and view all the answers

    What can be inferred if the time for starch disappearance during the experiment is very short?

    <p>The enzyme is highly active and effectively hydrolyzing starch.</p> Signup and view all the answers

    What indicates the presence of starch when iodine is added to the mixture?

    <p>A deep-blue-black color</p> Signup and view all the answers

    What does a red or gold color indicate after adding iodine?

    <p>Starch is completely hydrolyzed</p> Signup and view all the answers

    What impact do heavy metals have on enzyme activity?

    <p>They can inhibit enzyme activity.</p> Signup and view all the answers

    After how many minutes should the first observation be made to check for starch presence?

    <p>5 minutes</p> Signup and view all the answers

    What should be done every 5 minutes during the starch hydrolysis test?

    <p>Add fresh drops of iodine for testing</p> Signup and view all the answers

    Which of the following is a step in preparing for the Starch-Iodine Test?

    <p>Adding starch solution to iodine on a spot plate</p> Signup and view all the answers

    What is the primary purpose of using clean droppers for each mixture during the test?

    <p>To avoid contamination between samples</p> Signup and view all the answers

    What is recorded after testing each sample with iodine during the starch hydrolysis process?

    <p>The time for disappearance of blue-black color</p> Signup and view all the answers

    What is the optimal quantity of drop of starch used for testing in the spot plate?

    <p>1 drop</p> Signup and view all the answers

    What is the purpose of mixing distilled water with saliva in the procedure?

    <p>To dilute saliva for easier measurement of enzyme activity</p> Signup and view all the answers

    Which temperature should the water bath be maintained at during the experiment?

    <p>37°C</p> Signup and view all the answers

    What should be done if the temperature of the water bath exceeds 37°C?

    <p>Add tap water to cool it down</p> Signup and view all the answers

    What is the initial volume of starch solution placed in each test tube?

    <p>5 mL</p> Signup and view all the answers

    What role does chewing gum or rubber bands have in the experiment?

    <p>They help stimulate saliva secretion</p> Signup and view all the answers

    Why is it important to record the time when the test tubes are placed in the water bath?

    <p>To track the enzyme reaction duration for accurate results</p> Signup and view all the answers

    What type of starch solution is used in this procedure?

    <p>1% starch solution</p> Signup and view all the answers

    What is the main purpose of using a thermometer in this experiment?

    <p>To ensure accurate temperature of the water bath</p> Signup and view all the answers

    What is the role of inhibitors in enzyme activity?

    <p>They compete with substrates, preventing enzymes from catalyzing reactions.</p> Signup and view all the answers

    Why is an alcohol swab used prior to giving an injection?

    <p>To sterilize the skin and prevent infection.</p> Signup and view all the answers

    What is typically the optimum temperature for salivary amylase activity?

    <p>37°C</p> Signup and view all the answers

    Which of the following compounds is most likely to be an inhibitor of enzyme activity?

    <p>Heavy metals</p> Signup and view all the answers

    What is a potential result of a reaction with added inhibitors?

    <p>Decrease in reaction rate.</p> Signup and view all the answers

    What is the purpose of adding saliva solution to the test tubes in the experiment?

    <p>To provide the enzyme needed for starch hydrolysis</p> Signup and view all the answers

    How is enzyme activity expected to change as its concentration is increased?

    <p>Enzyme activity increases until it reaches a plateau</p> Signup and view all the answers

    What is the significance of the 37°C water bath in the experiment?

    <p>It provides optimal temperature for enzyme activity</p> Signup and view all the answers

    What effect does high temperature have on enzymes according to the guide questions?

    <p>Denatures enzymes leading to loss of activity</p> Signup and view all the answers

    What is the expected outcome of the starch test five minutes after enzyme addition?

    <p>Starch will remain unchanged in test tube 4 with water</p> Signup and view all the answers

    What role does pH play in enzyme activity as suggested in the experiment?

    <p>Optimal pH levels enhance enzyme function significantly</p> Signup and view all the answers

    What specific measurement is taken every five minutes during the experiment?

    <p>The time until the blue color of starch disappears</p> Signup and view all the answers

    Which of the following correctly describes the procedure for testing starch presence?

    <p>Add iodine reagent after mixing starch solution with saliva</p> Signup and view all the answers

    Study Notes

    Factors Affecting Enzyme Activity

    • Enzyme activity is influenced by factors such as enzyme concentration, substrate concentration, pH, temperature, and the presence of heavy metals.

    • Saliva contains amylase enzyme, which breaks down starch.

    • The experiment uses saliva as a source of amylase and 1% starch solution as the substrate.

    • Iodine reagent is used to test for the presence of starch. A blue-black color indicates starch is present while a red or gold color shows complete starch hydrolysis.

    Enzyme Concentration

    • The experiment tests the effect of enzyme concentration by varying the amount of saliva added to the starch solution.

    • Higher saliva concentration (more enzyme) leads to faster starch hydrolysis, indicated by a shorter time for the blue-black color to disappear.

    • Lower saliva concentration (less enzyme) results in slower starch hydrolysis, indicated by a longer time for the blue-black color to disappear.

    Temperature

    • The experiment investigates the effect of temperature on enzyme activity by exposing the reaction mixtures to different temperatures:

      • Ice-water bath (0°C)
      • Warm water bath (37°C)
      • Boiling water bath (100°C)

    • Enzyme activity is highest at an optimal temperature, usually around 37°C for salivary amylase.

    • Low temperatures slow down enzyme activity.

    • High temperatures can denature and inactivate enzymes, rendering them unable to catalyze reactions.

    pH

    • The experiment tests the effect of pH using different buffer solutions (pH 3, 5, 7, 9, 11).

    • Each buffer solution creates a specific pH environment for the enzyme reaction.

    • Enzyme activity is optimal at a specific pH, which varies depending on the enzyme. The optimal pH for salivary amylase is around 7.0.

    • Extreme pH values, either too acidic or too alkaline, can disrupt the enzyme's shape and function, reducing its activity.

    Heavy Metal Inhibition

    • The experiment assesses the effect of heavy metals on enzyme activity using:

      • Silver nitrate (AgNO3)
      • Sodium chloride (NaCl)

    • These heavy metal ions can bind to the enzyme's active site, preventing the substrate from binding and inhibiting enzyme activity.

    • The experiment uses ethanol as a control, as it is not expected to affect amylase activity.

    • Water is also a control, representing a basic reaction with no inhibitors present.

    Inhibition of Enzyme Activity

    • The experiment evaluates the inhibition of amylase activity by exposing the enzyme to:

      • Silver nitrate
      • Sodium chloride
      • Ethanol

    • The disappearance of the blue-black color indicates the hydrolysis of starch.

    • The time it takes for the color to disappear is used to measure enzyme activity.

    • The experiment demonstrates that heavy metals and alcohol can act as inhibitors of enzyme activity.

    • Ethanol is known to denature proteins, including enzymes, causing them to lose their functional shape and activity. This is why alcohol swabs are used prior to injections to disinfect and sterilize the skin, killing bacteria and minimizing the risk of infection.

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    Related Documents

    Enzyme Activity Lab (Biochemistry) PDF

    Description

    Explore the various factors that influence enzyme activity in this quiz. Learn about the roles of enzyme concentration, temperature, pH, and other elements in enzymatic reactions. Engage with practical examples involving amylase from saliva and starch hydrolysis tests.

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