Cellular Respiration lab

Cellular Respiration
Problem:
We are attempting to see how having a germinated specimen vs. ungerminated vs. non-living affects the rate of oxygen consumption. As time goes on throughout the lab we will be able to see the different rates of respiration that each of the samples will have.
Hypothesis:
If three different samples are taken and have the same mass but, have different compositions of living/non-living organisms, then the samples that have been germinated and have the highest composition of living organisms will have the highest rate of respiration and the samples that contain no living organisms will have the least amount of respiration.
Materials:

Tub of ice water  

3 vials

10 germinated peas

Ungerminated peas

Glass beads

Scotch tape

Thermometer 

KOH (Potassium Hydroxide)

3 Cotton balls

3 Non-absorbent Rayon

Food coloring

White paper

Timer

3 Pipettes

Dropper

Tweezers

Procedure:

1. Soak 3 cotton balls in KOH (Caution KOH is corrosive, use gloves and goggles) *Control

2. Use Tweezers to place KOH into each of the 3 vials. 

3. Place non-absorbent Rayon in each of three vials. *Control
4. Fill a glass vial with 10 germinating peas. *Independent Variable
5. Fill the 2nd glass vial with 10 ungerminated peas. *Independent Variable
6. Place glass beads in 2nd vial until it is of equal volume to first vial.
7. Place an equal volume to the 1st vial of glass beads into 3rd vial. *Independent Variable
8. Place stopper and pipette onto each vial.

Courtesy:http://www.biologycorner.com/worksheets/cellular_respiration_AP_Lab5.html

9. Place scotch tape across tub.
10. Place white paper into cold water.
11. Place thermometer in water.
12. Rest each pipette of the vials into the scotch tape. See below.

Courtesy:http://www.biologycorner.com/worksheets/cellular_respiration_AP_Lab5.html

13. Wait five minutes to allow beads and peas to adjust to water.
14. Remove Scotch tape.
15. Place drop of food coloring onto each opening of pipette using a dropper.
16. Submerge pipettes into ice water and remove tape.
17. Measure where air bubble is on pipette. *Dependent Variable (oxygen consumption).
18. record every two minutes
19. After ten minutes stop recording.

Results

	0 Min	2 Min	4 Min	6 Min	8 Min	10 Min
Vial 1	8 Ml	7.3 Ml	7 Ml	6.6 Ml	6.2 Ml	6 Ml
Vial 2	7.5 Ml	7.4 Ml	7.4 Ml	7.4 Ml	7.3 Ml	7.3 Ml
Vial 3	7.2 Ml	7.3 Ml	7.3 Ml	7.3 Ml	7.2 Ml	7.2 Ml

Discussion:

This lab demonstrates how organisms use up oxygen at different rates and that non-living organisms do not use oxygen. This allowed me to develop a deeper understanding of respiration because i was able to actually see it in action. 

It turns out that my original thought was correct that the germinating peas would require the most oxygen because they are trying to grow. I was also correct in my guess that the glass beads a non-living thing would not require much oxygen if any at all. 

Our group encountered a few issues that probably effected the result of the experiment. For example, the vials once place are supposed to be left undisturbed. we had several occasions where the vials would be disturbed for various reasons. this caused more oxygen to seep out of the vials. Obviously, this would skew our results. Also, if you look at our bead vial results you will notice that the oxygen fluctuated up and down. theoretically there should have been no change however, the was an obvious fluctuation even if it was just about a tenth of a mL. This was probably caused by either a lack of precision in making our measurements or there was an actual fluctuation due to movement of the vials. in order to prevent this in the future i think I would not let the tub be on a table i would place it on a more sturdy table and keep certain individuals away from it to reduce the amount of interaction near the vials. It would also be nice if we had maybe found a way to construct holders to ensure they remained still.

All in all the experiment had i's flaws but the results were close enough that we could still grasp the concept of what it was trying to teach us. 

Enzyme lab

For the experiment we were testing to see how much oxygen was created in a reaction of yeast and hydrogen peroxide. In order to test this we obtained a tub filled with water a graduated cylinder a ring stand, a rubber stopped a rubber tube and a glass cylinder and the yeast and hydrogen peroxide. We had to fill the tub with water about 3/4ths of the way full and then submerge the graduated cylinder in the water and leave it upside down. we then attached the graduated cylinder to the ring stand while leaving the opening in the water. Then we placed 10 mL of hydrogen peroxide in the glass cylinder. we attached the rubber tubing into the rubber stopper and had it ready to place back on the glass cylinder. we then added 1 mL of yeast and immediately placed the stopper on the cylinder. We had to quickly place the rubber tubing under water and inside the graduated cylinder. we kept track and at 30 second intervals we check the amount of air that had been created by the yeast and hydrogen peroxide reaction by counting the amount of bubbles and the how many mL the water had gone down in the graduated cylinder. we continued to check for 5 minutes. we then repeated this experiment using 1o mL of hydrogen peroxide and .75 mL of yeast.

I was expecting for there to be less air produced in the experiment where there was only .75 mL of water. However, we saw the opposite effect. though the results may show this (see attachment) I believe there may have been some human error. I think that there was air already trapped inside the rubber tubing and it was released into the graduated cylinder. Meaning that there was a significant amount of air that had been measured that was not created by the hydrogen peroxide/yeast reaction.

*Note- I had issues uploading the data table so it will be in an e-mail

For my experiment I was investigating whether the pill bugs would prefer a damp environment with living grass or an environment with dead molded grass. In order to test this I had to create each of these environments inside a testing tray. On both sides of the dish I placed a wet coffee filter and then placed dead grass on one side and then the living grass on the other. We released the pill bugs in the center of the tray and began timing. Every three minutes we counted the amount of pill bugs on each side. We continued doing this until 18 minutes had elapsed. Throughout the entire experiment it was obvious that the bugs preferred that dead molded grass as opposed to the living fresh grass. From the beginning of the time to the 9-minute marking there were 5 pill bugs in the dead grass and 3 in the living grass.  After that it remained split into 6 in the dead grass and 2 in the living grass until the 18 minute marking at which there were divided back into 5 in the dead grass and 3 in the living. Though these results seem to be rather convincing that pill bugs prefer dead molded grass you must also take into consideration the outside factors. For example, these bugs could have very well been extremely stressed out due to being contained in this area and having prior to the experiment been removed from an environment in which it was comfortable and then being trapped in a small container for several hours. Also there had to be some human interference due to the fact that the pill bugs were constantly trying to escape. We constantly had to push the bugs back into the testing tray. Despite these flaws the results were what I expected. Because I had found the pill bugs in an environment that had damp molded grass it would only make sense that they would prefer this environment.