Cellular Respiration Essay, Research Paper
The purpose of this lab is to observe the rate of cellular respiration in a given organism by
observing the amount of oxygen gas taken in and the amount of carbon dioxide expelled by the
peas. The oxygen will be measured at 2 different temperatures and the carbon dioxide amount
will be determined by stochiometry after it has reacted with potassium hydroxide to form water
and potassium carbonate.
-calculate the rate of cellular respiration from the obtained data.
-observe how cellular respiration works.
-use a chemical raection in oreder to find out the amount of initial reactant.
H0= The germinating peas will have the greatest respiration rate.
H1= The dry peas and beads will have the second highest respiration rate.
H2= The test tube with beads alone will have the lowest cellular respiration rate.
All materials are stated on lab sheet.
1. Obtain the volume of 25 germinating peas using the water displacement method. Dry
the peas. Also, set up the water baths, one at room temperature and the other at 10
2. Again using the water displacement method, place 25 dry peas in the water, and add
beads until the total displacement of the germinating seeds is reached. Dry the peas.
3. Once again use the water displacement method tp attain the number of beads that
would be needed to displace the same amount of water as the 25 germinating peas
4. Repeat 1-3 with different peas. Set all these peas aside for later.
5. Assemble 6 respirometers. Take 6 vials and put a small swab of cotton in the bottom
of each. Saturate the cotton with 15%KOH. Dry the inside of the respirator vials.
Place a dry swab of cotton on top of the soaked one.
6. Put each set of peas in a vial. One set of 3 will be used at room temperature, and the
other will be used in the 10 degree water bath. Put the stopper with the
attached pipette on each. Place the weighted collar on each vial.
7. Create a bridge of masking tape to hold the pipettes out of water during the
equilibration period of 7 minutes.
8. After that time eriod, immerse all the vials in their respective baths. Arrange the
pipettes so that they can let me read from out of the water without having to br
9. After 3 minutes, record the initial reading of the pipette on each vial. Check the
temperature of the baths as well. For every 5 minutes as 20 minutes as elapsed, take
the position of the water in each pipette.
In this experiment, the data proved by my hypotheses was to be correct. Starting with the
new beads and ending with the germinating peas, the respiration rate increased. Additionally,
there was an increase in resoiration rates with both types of peas at a higher temperature. These
conclusions were derived from calculating the amount of oxygen used in each vial. The greater
the amount of oxygen used, the higher the respiration rate.
Sources of Error:
Possible sources of error in this experiment include water leaking into the vial, and other
human errors. For instance, not measuring the volume correctly, or not putting enougfh KOH
into the bottom of each vial. Additionally, if the temperatures weren t exactly 10 degrees celsius
or room temperature, the results also would have been thrown off.