1. Cell Respiration
LabQuest Activity 11B
Cell respiration refers to the process of converting the chemical energy of glucose into a form usable by organisms. Glucose may be oxidized (broken down) completely if sufficient oxygen is available as shown in the following reaction:
C6H12O O2  6H2O + 6CO2 + energy
Learning Targets:
In this experiment you will…
Use a CO2 Gas Sensor to measure concentrations of carbon
dioxide during respiration.
Study the effect of temperature on cell respiration rate.
Compare the rates of cell respiration in germinating and
non-germinating peas.

2. Copy the following table into your lab notebook:
PROCEDURE
Copy the following table into your lab notebook:
If your CO2 sensor has a switch, set it to the low setting. Connect the CO2 Gas Sensor to LabQuest and choose New from the File menu.
On the Meter screen tap Length with the LabQuest stylus. Change the data-collection length to 300 seconds.
Obtain 25 germinated peas and blot them dry between two pieces of paper towel.
Peas
Rate of Respiration
(ppm/s)
Germinated, room temperature
Non-germinated, room temperature
Germinated, cool temperature

3. Place the germinated peas into the respiration chamber.
Place the shaft of the CO2 Gas Sensor in the opening of the respiration chamber.
Wait one minute, then start data collection.
Data will be collected by the LabQuest device for 5 minutes.
When data collection has finished, a graph of carbon dioxide gas versus time will be displayed.
Remove the CO2 Gas Sensor from the respiration chamber. Place the peas in a 100 mL beaker filled with cold water.
The cold water will prepare the peas for the second part of the experiment.

4. Use a piece of paper to fan air across the openings in the probe
shaft of the CO2 Gas Sensor for one minute.
Fill the respiration chamber with water and then empty it. Thoroughly dry the inside of the respiration chamber with a paper towel.
Using the LabQuest device, perform a linear regression to calculate the rate of respiration:
 Choose Curve Fit from the Analyze menu.
 Select Linear for the Fit Equation.
The linear-regression statistics for these two data columns
are displayed for the equation in the form: y = mx + b,
where x is time, y is CO2 concentration, m is slope, and
b is the y-intercept.
 Enter the slope, m, as the rate of respiration for germinated
peas (room temperature) in the data table.
 Select OK.

5. Store the data from the first run by tapping the File Cabinet
icon.
Repeat steps 4 – 13 substituting the germinated peas with
non-germinated peas. In step 9 place the non-germinated peas in a petri dish (NOT in an ice bath).
Part II – Germinated Peas, Cool Temperatures
15. Remove the peas from cold water and blot them dry between two paper towels.
Repeat steps using the cold peas. When you have completed step 12 skip directly to step 17.
Graph all three runs of data on a single graph.
 To view a graph of CO2 concentration vs. time showing all
three data runs, tap Run 3 and select All Runs.
 All three runs will now be displayed on the same graph axes.
 SAVE (use the last name of a group member)

6. QUESTIONS
Please answer the following questions
on a separate sheet of paper using complete sentences…
1. Did this lab activity provide evidence that cell respiration occurred in peas? Explain how you know.
2. Compare the rate of respiration for germinating
pea seeds versus non-germinating pea seeds.
3. Why do germinated peas undergo cell respiration?
4. What is the effect of temperature on the rate of
cell respiration in peas?
5. How was the rate of respiration calculated?
(Hint: Think of the equation of a line.)
Express the rate of respiration for germinating
pea seeds to the nearest thousandths place.