Enzyme Lab Lecture Notes

Introduction

• Today's focus: Enzyme lab as part of the enzyme unit.
• Objective: Observe enzyme activity using common household items.
• Materials:
  • Yeast (from grocery store)
  • Hydrogen Peroxide (3% solution, e.g., CVS bought)

Background Information

• Enzyme: Catalase (found in yeast)
  • Substrate: Hydrogen Peroxide (H₂O₂)
  • Reaction: Catalase breaks H₂O₂ into water (H₂O) and oxygen (O₂).
  • Observation: Production of oxygen gas forms bubbles, causing filter paper to rise in solution.

Experiment Setup

• Hydrogen Peroxide Concentrations:
  • 3% (original solution)
  • 1.5%
  • 0.75%
  • 0.375%
• Prepare a table for recording different concentrations and observations.
• Pre-lab tasks: Read background info, answer pre-lab questions.

Procedure

1. Yeast Solution Preparation:
   • Pre-mixed and left to activate for 5 minutes.
   • Yeast in water helps activate dehydrated yeast for the enzyme reaction.
2. Test Tubes Preparation:
   • 15 ml test tubes, each filled with 10 ml of respective H₂O₂ solution.
   • Ensure consistency in solution volume.
3. Filter Paper Discs:
   • Use a hole punch to cut out filter paper discs.
   • Dip discs in yeast solution for ~5 seconds, then drain on paper towel.

Experiment Steps

• Place each filter paper disc on the lid of a test tube.
• Invert test tube to start the reaction and time how long it takes for the disc to rise.
• Conduct three trials per concentration to ensure accuracy.

Observations and Results

• 3% H₂O₂:
  • Times: 12s, 7.62s, 12s
• 1.5% H₂O₂:
  • Times: 14.41s, 14.8s, 14.14s
• 0.75% H₂O₂:
  • Times: 18.39s, 16.78s, 16s
• 0.375% H₂O₂:
  • Times: 84s, 74s, 57s
• Trend: Lower concentrations of H₂O₂ take longer for the reaction to complete due to less substrate availability.

Discussion Points

• Consider factors affecting reaction rate, e.g., concentration, temperature.
• Explore possibilities for speeding up the reaction.

Conclusion Tasks

• Data Analysis:
  • Calculate average time and reaction rate.
  • Graph the rate of reaction versus substrate concentration.
• Conclusion Writing:
  • Discuss the manipulated variable and its effect.
  • Suggest future experiments or modifications for further exploration.

Final Steps

• Ensure all data is recorded accurately.
• Complete calculations and graph creation.
• Write a conclusion and reflect on the findings and future directions.

End of Lab Session

• Remember to review your data and analysis before submission.