BIO 3A Lab: Cellular Respiration (02/09) Page 1 of 4
Biology 3A LABORATORY
Cellular Respiration and Fermentation
Objectives
• To study processes of anaerobic and aerobic respiration
• To determine the amount of oxygen consumed during aerobic respiration
• To determine the amount of carbon dioxide produced during aerobic respiration
• To study the effect of substrate difference on anaerobic respiration in yeast
• To investigate the process of fermentation used in food making
PLEASE BRING A USB THUMBDRIVE TO LAB TODAY
Introduction
All living organisms require energy in order to sustain the many processes involved in life.
The energy f or these processes is provided by cellular respiration, a catabolic process that
releases energy (exergonic), most often as ATP. It is essential that the chemical reactions
involved in cellular respiration occur at a rapid rate and within optimum conditions. Enzymes
are critical in this process.
Aerobic respiration in germinating peas
Cellular respiration involves glycolysis, the Krebs cycle and the electron transport chain.
As you may recall from lecture, glycolysis is essentially an anaerobic process since it is not
dependent upon the presence of oxygen. The fate of pyruvate, the end product of glycolysis, is
dependent on the presence of oxygen. If oxygen is not present, the two pyruvates (from the
complete oxidation of one glucose molecule) will r emain in the cytosol and undergo the
anaerobic process called fermentation. There is no “ extra” energy yield from fermentation. If
oxygen is present, the pyruvates will be shuttled to a mitochondrion, altered and enter into a
series of reactions involving the Krebs cycle and the Electron Transport Chain (ETC). Both of
these processes are dependent on the presence of oxygen and ar e aerobic in nature. T he
Krebs cycle only produces 1 ATP molecule directly per cycle. However, it is indirectly
responsible for the greatest ATP production by generating coenzymes, both NADH and FADH
2
.
When these coenzymes are reoxidized in the electron transport chain, many molecules of ATP
are generated (a theoretical 36 – 38 ATP per glucose). Many living organisms undergoing
aerobic respiration will use oxygen and produce carbon dioxide.
In th is lab you will indirectly determine metabolic rate during aerobic respiration in
germinating peas placed in a manometer (a closed chamber) by monitoring the amount of CO
2
produced.
Procedure A:
Setup:
1. Obtain 10 – 12 four- to six-day old germ inating peas, determine the mass and record the
mass on Table 3.
2. Obtain one Pasco Xplorer GLX data l ogger, CO
2
probe and the CO
2
measurement
container.
3. To the container, add a 2 cm ball of absorbent cotton to the bottom.
4. Add normal peas to the container.
5. Wrap the container with aluminum foil to inhibit photosynthesis.
6. Place the CO
2
probe onto the container.
BIO 3A Lab: Cellular Respiration (02/09) Page 2 of 4
Measurement:
1. Connect the CO
2
probe to the Xplorer GLX WITHOUT tipping the container upside down (do
not let the wet peas hit the measuring probe) to one of the four PASPORT sensor ports
(They look like serial cable ports at the top end of the screen).
2. Turn on the GLX (small green button on the bottom left hand side of the handle)
3. If the Graph is not already displayed on the screen press the Home Screen ( ) and F1
( ) at the same time to go to the Graph.
4. If you need to start a new graph, Press F4 then press #7 to start a new graph ready to
display data from the PASPORT sensor.
5. Equilibrate the sealed peas in the container for 5 minutes on the table. Do not handle the
containers with your warm hands to assure accurate results.
6. After five minutes, Press to start data recording for 10 minutes.
7. To stop data recording, press again.
8. Press the Home Screen ( ) button for the menu display.
9. Use the cursor and select Graph menu and press activate ( ).
10. Return the peas to the original container and discard the used cotton ball. Clean out the
container if need be. Do not remove the aluminum foil.
11. Obtain a new 2 cm cotton ball and repeat the procedure with the freeze/thawed peas.
To Download your data to your USB device:
1. Attach your USB drive to the USB port on the right side of the display to save your file to
your USB drive.
2. Select Data Files, press ( ).
3. Select the file and press F1. Next to the name, it should say [Open].
4. Press Home ( ).
5. Cursor down to Table and press activate ( ).
6. Press F4 and cursor down to Export All Data and press ( ).
7. Your data should be downloaded to you drive.
8. Open Excel and select the file (Export file) from your drive. The Text Import Wizard will
pop-up.
9. Click Next. Make sure that TAB is selected (that’s the default) on the Tab Delimiters and
click next.
10. Using Excel, select scatter plot for the entire 10 minute duration. Add a trendline with the
equation and r
2
value.
11. Return the peas to the original container and discard the used cotton ball. Clean out the
container for the next group.
CO
2
production during aerobic respiration
From the acid, bases an d buffers lab, you sho uld recall that CO
2
can combine with wa ter to
form carbonic acid, which dissociate as follows:
CO
2
+ H
2
O H
2
CO
3
H
+
+ HCO
3
-
H
+
+ H
+
+ CO
3
2
-
(3)
