AP Biology Lab 5 Walkthrough: Cellular Respiration

Presented by Mr. Andersen

Overview

• Focus on cellular respiration in eukaryotic cells.
• Key organelle: Mitochondria.
• Cellular respiration process:
  • Inputs: Glucose and Oxygen
  • Outputs: Carbon Dioxide, Water, and ATP (Energy).

Steps of Cellular Respiration

1. Glycolysis
   • Occurs outside the mitochondria.
2. Krebs Cycle
   • Occurs inside the mitochondria.
   • Produces CO2, NAD, and FAD.
3. Electron Transport Chain
   • Utilizes energy from NAD and FAD to produce ATP.

Lab Focus: Measuring Rate of Respiration

• Objective: Measure oxygen consumption rate to determine respiration rate.
• Organisms Used in Lab:
  • Worms
  • Peas (demonstrates plant respiration)

Respirometer Setup

• Key Components:
  • Glass jar with weights at the bottom.
  • Absorbent cotton with Potassium Hydroxide (KOH) to convert CO2 into a solid.
  • Pipette for measurement.
• Control and Experimental Setups:
  • Germinating peas, dry peas, and glass beads as controls.
  • Glass beads used to account for temperature fluctuations.

Experimental Procedure

1. Place KOH and cotton at the bottom.
2. Add pea seeds.
3. Seal and calibrate with a pipette.
4. Use three setups: germinating peas, dry peas, beads.
5. Observe and measure oxygen consumption over time (0, 5, 10, 15 minutes).
6. Water pressure moves air bubble as oxygen is consumed.

Data and Results

• Graph Interpretation:
  • Y-axis: Milliliters of oxygen consumed.
  • X-axis: Time in minutes.
  • Steepest slope indicates highest respiration rate.
• Findings:
  • Germinating peas exhibit the highest rate of respiration.
  • Worms and non-germinating peas show lower rates.
  • Non-germinating peas lack cellular respiration unless activated by soaking.

Conclusion

• Germinating peas have the highest rate of cellular respiration.
• Temperature and activation conditions affect respiration rates.
• Use linear graph and histogram for visualizing data.

Final Thoughts

• The lab effectively measures respiration rates using a simple and elegant experimental setup. This is crucial for understanding cellular respiration dynamics in various organisms.