IB Respiration CO2 & O2 Exploration Activity

Cell respiration refers to the process of converting the chemical energy to organic molecules into a form immediately usable by organisms.  Glucose may be oxidized completely if sufficient oxygen (aerobic respiration) is available according to the following equation:

All organisms, including plants and animals, oxidize glucose for energy. This energy is often used to convert ADP and phosphate into ATP.  Beans undergo cell respiration during germination.  In this exploration activity, you will observe differences between germinating (chick pea pods soaked in H2O for approximately 24 hours) and non-germinating peas (not soaked in H2O).

Objective: Measure gas production in germinating and non-germinating pea pod seeds.


  1. If your CO2 Gas Sensor has a switch, set it to the Low setting.  Connect the CO2 Gas Sensor to channel 1 and the O2 Gas Sensor to Channel 2 of the Vernier computer interface.

  1. Prepare the computer for data collection by opening the file “11B Cell Resp” from the “ Biology with Vernier” folder of Logger Pro.

  1. Obtain 35g germinating beans and blot them dry between two pieces of paper towel.  Use the thermometer to measure the room temperature.  

  1. Place the beans into the respiration chamber.

  1. Place the O2 Gas Sensor into the BioChamber.  Insert the sensor snugly into the grommet.  The O2 Gas Sensor should remain vertical throughout the experiment.  Place the CO2 Gas Sensor into the neck of the respiration chamber.

  1. Wait four minutes for readings to stabilize then begin collecting data by clicking “Collect.”  Data will be collected automatically for 10 minutes.

  1. Remove the peas and return them to their original container.  Fill the respiration chamber with water and then empty it.  Thoroughly dry the inside of the respiration chamber with a paper towel.
  2. Determine the rate of respiration:
  1. Click anywhere on the CO2 graph to select it.  Click the Linear Fit button, to perform a linear regression.  A floating box will appear with the formula for a best fit line.
  2. Record the slope of the line, m, as the rate of respiration for germinating peas at room temperature.
  3. Close the linear regression floating box.
  4. Repeat steps 9a-c for the O2  graph.

  1. Obtain 35g non-germinating beans and place them in the cleaned respiration chamber.

  1. Repeat steps 4-10 for the non-germinating beans.


Table 1. Temperature of Room


Temperature (Celsius)


Table 2. Quantified Rate of Respiration (CO2 & O2) in Germinating & Non-Germinating Beans


CO2 Rate of Respiration (ppt/min)

O2 Rate of Respiration (ppt/min)

Degree of Uncertainty/Error



Table 3. Qualitative Data of Respiration (CO2 & O2) in Germinating & Non-Germinating Beans




  1. Share your data with the class by adding it here (and on website, don’t add units to your numbers).

  1. What evidence do you have the cell respiration occurred in the beans?  Explain and justify.

  1. Why do germinating beans undergo cell respiration?

  1. Were both bean types undergoing cellular respiration?  Explain why or why not for both.

  1. Explain the difference between anaerobic and aerobic respiration in regards to what happens to pyruvate.

  1. Using the class data and averages, found here (and on website), create two different graphs to display the average rate of respiration, one for CO2 and one for O2.  Be sure to include error bars to compare the results of the CO2 and one for O2 results.  Upload your graphs below.

  1. Conduct a t-test to assess for the results of the germinating and non-germinating beans.


Lab Standard: Analysis



Nearly Meets


Lab Standard: Evaluation



Nearly Meets


A full explanation of the lab standard rubric can be found here