Cellular Respiration Lab (Aerobic Respiration)
Perform the lab experiment below and complete a typed lab report.
Lab report due date ______________
Purpose: To explore carbon dioxide production and oxygen usage by a variety of
organisms.
Background Information: Write 3 – 5 sentences describing the process of aerobic
cellular respiration. Summarize the pathway and products of this metabolic pathway.
Hypothesis: Predict which of the following organisms will have the highest carbon
dioxide production as measured by the consumption of oxygen (rate of respiration).
Materials:
Plastic retainers, latticed organism holder, carbon dioxide absorbent(potassium hydroxide
– DO NOT TOUCH!), index solution, capillary tube, metabolism chamber, forceps,
calibrated tube, rubber tubing, chamber cap
Procedures:
1. Place the plastic retainer inside the latticed organism holder approximately ½ inch
from one end so it makes a plug.
2. Fill the organism holder with living material as instructed by your teacher.
3. Place another retainer in the organism holder to plug the other end.
4. Prepare another latticed organism holder as above but replace the living material with
an equivalent mass of non living material.
5. Place 12 – 15 pellets of Carbon Dioxide Absorbent into the chamber using the
FORCEPS! **Potassium Hydroxide is a strong alkali Avoid direct contact with skin
or clothing. Wash several minutes with running water if it gets on skin or eyes**
These pellets remove carbon dioxide from the atmosphere of the chamber as fast as it is
given off.
6. Make sure the rubber tubing is place on the tip of the chamber cap. Then place the
calibrated tube into the tubing.
7. Place the latticed organism holder into the chamber so it fits over the extrusion in the
bottom of the chamber.
8. Add index solution to the calibrated tube by placing the tip of the tube in the solution
so that about 1 centimeter of sulotion is drawn into the tube. This provides a moveable
seal at one end.
9. Now, place the cap with the capillary tube attached so that its extrusion fits inside the
latticed holder and place it firmly in the chamber.
10. Assemble the control in the same manner as described above.
11. Place the chamber in a horizontal position.
NOTE: The chamber is sensitive to temperature changes. Keep away from heat sources
such as hands, sunny windows, etc.
12. Allow the chamber to rest for 3 -5 minutes so gas pressure may reach equilibrium.
When the outer edge of the index solution reaches the scale on the capillary tube record
this on your data table as the initial reading.
For the next 5 minutes record the position of the outer edge of the index solution at one
minute intervals for both chambers (experimental and control). You may need to record
your readings faster or slower depending on how fast your index solution moves on the
tube.
Calculate the amount of oxygen consumed per hour by each organism using the
following equation:
No. of units on tube x 0.01 cc X 60 sec X 60 min. = cc of Oxygen/hour
Time in seconds
1 min.
1 hour
Calculate the rate of cellular respiration of each organism using the following equation:
Cc of oxygen per hour
Mass of organism(gm)/1000
=
cc of oxygen/kg/hour
Data:
Time (sec)
Organism 1
Organism 2
Organism 3
Control
Name__________
Name__________
Name__________
Name__________
Rate of Cellular
Respiration
Results: Graph the rate of cellular respiration for each organism and the control.
Conclusion: Did your hypothesis match your results? Why or why not?
Application:
1. What other variables might we have changed to see the effect it would have on the rate
of cellular respiration?
2. What other types of organisms might we have used for this experiment?
3. What results would you expect to see of we kept recording data for an hour or more?
4. What might have been a source of experimental error in this experiment?