AS and A Level Biology 37 Views 1 Answers
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Sourav PanOctober 28, 2024

Investigate the progress of enzyme-catalysed reactions by measuring rates of formation of products using catalase and rates of disappearance of substrate using amylase

Investigate the progress of enzyme-catalysed reactions by measuring rates of formation of products using catalase and rates of disappearance of substrate using amylase

Sourav Pan
Sourav PanOctober 28, 2024

Answered

Investigation: Progress of Enzyme-Catalysed Reactions

Reactions Under Investigation:

  1. Catalase-Catalysed Reaction:
    • Reaction: 2H₂O₂ (Hydrogen Peroxide) → 2H₂O (Water) + O₂ (Oxygen)
    • Measured: Rate of Formation of Product (O₂)
  2. Amylase-Catalysed Reaction:
    • Reaction: Starch (or Amylose) → Maltose (and eventually Glucose)
    • Measured: Rate of Disappearance of Substrate (Starch)

Experimental Design:

Catalase-Catalysed Reaction (O₂ Formation)

  • Materials:
    • Catalase solution
    • Hydrogen peroxide (H₂O₂)
    • Gas syringe or oxygen sensor
  • Procedure:
    1. Prepare several identical reactions with catalase and H₂O₂.
    2. Initiate each reaction at timed intervals (e.g., every 2 minutes).
    3. Measure the volume of O₂ produced (using a gas syringe) or the concentration of O₂ (using an oxygen sensor) at fixed time points (e.g., every 1 minute) after initiating each reaction.
    4. Plot the volume/concentration of O₂ vs. time for each reaction start time to observe the rate of product formation over time.
  • Data Analysis:
    • Calculate the initial rate of reaction (rate of O₂ formation) for each reaction using the linear portion of the plot.
    • Compare the initial rates among the reactions to assess the consistency of the catalase activity.

Amylase-Catalysed Reaction (Starch Disappearance)

  • Materials:
    • Amylase solution
    • Starch solution
    • Iodine solution (for starch detection)
  • Procedure:
    1. Prepare several identical reactions with amylase and starch.
    2. Initiate each reaction at timed intervals (e.g., every 2 minutes).
    3. At fixed time points (e.g., every 1 minute) after initiating each reaction, withdraw a sample and add iodine solution.
    4. Measure the absorbance (using a spectrophotometer) or color intensity (visually or with a colorimeter) of the resulting solution, which correlates with the remaining starch concentration.
    5. Plot the absorbance/color intensity (proportional to starch concentration) vs. time for each reaction start time to observe the rate of substrate disappearance over time.
  • Data Analysis:
    • Calculate the initial rate of reaction (rate of starch disappearance) for each reaction using the linear portion of the plot.
    • Compare the initial rates among the reactions to evaluate the consistency of the amylase activity.

Expected Outcomes and Interpretations:

  • Catalase Reaction:
    • Plot: Volume/Concentration of O₂ vs. Time will show a rapid increase in O₂ production initially, followed by a plateau as H₂O₂ is depleted.
    • Initial Rate Analysis: Consistent initial rates among reactions indicate reliable catalase activity.
  • Amylase Reaction:
    • Plot: Absorbance/Color Intensity (proportional to Starch Concentration) vs. Time will decrease over time, indicating starch breakdown.
    • Initial Rate Analysis: Similar initial rates across reactions suggest consistent amylase activity.

Factors Influencing Rates (Variables to Consider for Future Investigations):

  • Enzyme Concentration: How does varying the amount of catalase or amylase affect the reaction rates?
  • Substrate Concentration: What impact does changing the initial H₂O₂ or starch concentration have on the reaction rates?
  • Temperature and pH: How do variations in temperature and pH affect the activity of catalase and amylase, and consequently, the reaction rates?

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