AP BIOLOGY
Cellular Respiration
Cellular respiration refers to the process of converting the chemical energy of organic molecules
into a form immediately usable for organisms. Glucose may by oxidized completely if sufficient oxygen is
available by the following equation:
Light + C6H12O6 + 6 O2 (g)
6 H2O + 6 CO2 (g) + energy
All organisms, including plants and animals, oxidize glucose for energy. Often this energy is used
to convert ADP and phosphate into ATP. It is known that soybeans undergo cellular respiration during
germination. Do soybeans undergo cellular respiration before germination? The results of this experiment
will verify that germinated soybeans do respire. Using your collected data, you will be able to answer the
question concerning respiration and non-germinated soybeans.
Using the O2 and CO2 Gas Sensors, you will monitor the production and/or consumption of CO2
by soy beans during cellular respiration. Both germinated and non-germinated soy beans will be tested.
Additionally, cellular respiration of germinated soy beans at two different temperatures will be tested.
Materials
Vernier LabQuest w/AC Adapter
ice cubes
plastic tub
Vernier CO2 Gas Sensor
scotch tape
250-mL respiration chamber
25 germinated soy beans
25 non-germinated soy beans
one 250- mL beaker
thermometer
Procedure
*NOTE
ALWAYS KEEP THE O2 SENSOR IN THE UPRIGHT POSITION!!
Keep the CO2 sensor on its side! After 1 ½ minutes, gently shake it to make
sure CO2 is being read by the sensor.
DAY 1:
LabQuest Setup
1. Plug the CO2 Gas Sensor into Channel 1 on the top of the LabQuest.
2. Turn on the Vernier LabQuest (the power button is located at the top left corner of the LabQuest
directly above the red sticker)
**For all of the “Clicking” used in this lab, use the stylus that is plugged into the top of the
LabQuest. Make sure to press the screen firmly! Do not just “tap” at it, because it will not be
read by the LabQuest.**
3. The first screen that you see when you turn on the LabQuest is your home screen. To set up your
sensors:
a. Click on “File” in the top left corner and then click on “New”.
b. Click on “Sensors” and then click on “Sensor Setup”
c. Click on the Drop Down Box for CH 1 and select “CO2 Gas Low”. Click on the arrow next to
“CO2 gas” to get a drop down menu and then click “low.” Make sure this is set to “ppt” as well.
d. Click “Ok” in the bottom right hand corner. This should move you back to your home screen, and
it should now show the CO2 sensors making readings.
4. Set up the data-collection mode.
a. Click on the “Mode, Rate & Length” box on the right side of the screen.
b. Ensure that the Mode is “Time-Based”
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c. Adjust the Rate so that it is .25 samples/s.
d. Adjust the Interval so that is 4 s/sample
e. Set the length to 300s.
f. Click “OK” to take you back to the home screen.
g. On the top of the screen, click on the second tab that looks like a tiny graph.
Record the temperature of the room.
Obtain 25 non-germinated soy beans from the teacher.
Place the non-germinated soy beans into the respiration chamber.
Place the CO2 gas sensor into the bottle. Gently push the CO2 sensor into the connector until it stops.
The sensor is designed to seal the bottle without the need for unnecessary force. Make sure the bottle
is on its side!
Wait two minutes, and then click the green play button (bottom left on the screen) to begin data
collection. Data will be collected for 5 minutes.
At approximately halfway (3 minutes), gently swirl the bottle to mix around the gases.
When data collection has finished, leave the graph on the screen and plug in a USB (top left on
LabQuest).
Go to the Graph button of the LabQuest and select File.
Click “File” and select “Save” from the drop-down list. Select the USB icon then name of the USB and
click “OK”.
Unplug your USB from the LabQuest and plug it into the student computers.
Open Logger Pro on your computer.
Select “File”
Select “Open.” Find your flash drive, select it, and open the file you saved previously.
Double click the graph.
In the upper left of the pop-up box enter a title for your graph.
Click “done.”
Select “File,” then “Print,” then “OK.”
Change your printer to “icafe” and click “OK.”
Find your graph at the printer.
Remove the CO2 Gas Sensor from the respiration chamber. Return the non-germinated soy beans to
the teacher.
Data for Day 1:
Condition
Temperature (oC)
DAY 2:
1. Plug the CO2 Gas Sensor into Ch. 1. Turn on the LabQuest. To set up the sensors, repeat steps 3a-d
from the Day 1 procedure.
2.
To set up the data-collection mode, repeat steps 5a-g from the Day 1 procedure.
GROUP 1:
3. Record the temperature of the room.
4. Obtain 25 germinated soy beans (this amount covers the bottom of the respiration chamber’s cap
located in the box) and blot them dry between two pieces of paper towel.
5. Place the germinated soy beans into the respiration chamber.
6. Place the CO2 gas sensor into the bottle. Gently push the CO 2 sensor into the connector until it stops.
The sensor is designed to seal the bottle without the need for unnecessary force. Make sure the bottle
is on its side!
7. Wait two minutes, and then click the green play button and the bottom-left of the screen.
When data collection has finished, ,plug in a USB (top left on LabQuest).
Click “File” and select “Export” from the drop-down list. Select the name of the USB and click “OK”.
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Remove the USB from the LabQuest and plug it into the computer. Select the graphs that were just
saved onto the USB and print them out using the Logger Pro instructions from above (steps 16-24).
Make a copy for each person in the group. Be sure to add a title, increments and any other necessary
items to the graph.
8. Remove the CO2 Gas Sensor from the respiration chamber. Throw the germinated soy beans away.
9. Fill the respiration chamber with water and then empty it. Thoroughly dry the inside of the respiration
chamber with a paper towel.
10. When finished, turn off the LabQuest.
11. Record one group’s data from the board for the COLD TEMPERATURE germinated soy beans.
GROUP 2:
25. Place 25 germinated soy beans in a 250-mL beaker filled with cold water and ice cubes. Wait 5
minutes then record the temperature of the ice water.
26. Ensure the strainer is in place in the sink before obtaining the germinated soy beans from the ice water.
Blot them dry with a paper towel. Place them in the respiration chamber.
27. Place the respiration chamber in the plastic tub. Surround the chamber with ice and water.
28. Repeat steps 8-25 for the cold germinated soy beans.
29. Remove the CO2 Gas Sensor from the respiration chamber. Throw the germinated soy beans away.
30. Fill the respiration chamber with water and then empty it. Thoroughly dry the inside of the respiration
chamber with a paper towel.
31. When finished, turn off the LabQuest.
32. Record one group’s data from the board for the ROOM TEMPERATURE germinated soy beans.
Data for Day 2:
Condition
room
cold water
Temperature (oC)
Questions for Groups 1 and 2:
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Do you have evidence that cellular respiration occurred in the soy beans? Explain.
What is the effect of germination on the rate of cellular respiration in soy beans?
What is the effect of temperature on the rate of cellular respiration in soy beans?
Why do germinated soy beans undergo cellular respiration?
Given your extensive knowledge of cell processes, explain what else would affect cellular respiration.
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