Cellular Respiration Lab 11/27/11

How does germination affect the respiration that cells undergo?  The main purpose of this lab was to test whether there is a difference in germinating cells or non-germinating cells.

My hypothesis for this experiment was that if there are more germinating cells, then they will respire more than the dry cells over time. This is because germinating cells are more likely to respire more and give off more carbon dioxide than non-germinating cells.

The materials needed for this lab are:

 two large trays, thermometers, water, ice, six vials, steel washers, 100 mL graduated cylinder, glass beads, germinating peas, dry non-germinating peas, cotton ball, non-absorbent rayon, 15% potassium hydroxide (KOH), graduated pipet, and a stopper.

Be sure to use gloves, goggles, and an apron for this lab because the KOH is corrosive. BE VERY CAREFUL.

The procedure for this lab is as follows:

1. Set up the waterbaths in the large trays. One should be less than 10 degrees Celsius at all times by using ice.

2. Obtain six vials and place steel washers at the bottoms. Number these vials.

3. Fill the graduated cylinder halfway with water. Add 10 germinating peas and take a reading of the displaced water. Calculate the difference and record this data as the volume of the germinating peas.

4. Redo step 3 but by adding 10 dry non-germinating peas and glass beads until the water level is the same as the germinating peas.

5. Redo step 3 but by adding glass beads to the water level of the germinating peas. This is what is being compared and tested against.

6. Dry the peas and beads and repeat steps 3-5 for the second set of vials.

7. Place the cotton balls in each of the bottoms of the vials.

8. Using a pipet, add 1 mL of the 15% KOH to the cotton ball. Then, add a piece of rayon on top of the cotton ball.

9. Place the germinating peas, non-germinating peas and glass beads, and glass beads in vials 1-3 and 4-6.

10. Insert the graduated pipet into the wide end of the stopper. Be sure the tapered end of the pipet is furthest away from the stopper. Do this for all of the vials.

11. Insert the stopper into the vials. Place a washer over the pipet and let it rest on the stopper.

12. Place the first 3 vials in the room-temperature waterbath and the last 3 in the chilled waterbath with thermometers in both. Be sure that the tips of the pipets are resting on the edge and not in the water.

13. Add a drop of food coloring to the tip of the pipet and wait one minute. Carefully immerse the vials into the water. Let the vials sit and equilibriate for 5 minutes before recording.

14. Record the initial reading and temperature in your data table and every 5 minutes for 30 minutes record the new readings.

15. When all of the readings have been taken, calculate the difference and corrected difference for each result.

Difference= (initial-final)

Corrected Difference= (initial pea reading-pea reading at time)-(initial bead reading- bead reading at time)

16. Graph results

(Time is the independent variable and the amount of difference is the dependent variable.)

Temp.	Time	Reading for Germinating peas	Difference	Corr. Diff.	Reading for Dry peas	Difference	Corr. Diff.	Reading Beads	Difference
25	0	.91	0	0	.92	0	0	.93	0
25	5	.84	.07	.05	.89	.03	.01	.91	.02
25	10	.77	.14	.11	.87	.05	.02	.90	.03
25	15	.71	.20	.17	.86	.06	.03	.90	.03
25	20	.64	.27	.24	.85	.07	.04	.90	.03
25	25	.58	.33	.30	.84	.08	.05	.90	.03
25	30	.51	.40	.37	.83	.09	.06	.90	.03

Temp.	Time	Reading for Germinating peas	Difference	Corr. Diff.	Reading for Dry peas	Difference	Corr. Diff.	Reading Beads	Difference
8	0	.92	0	0	.91	0	0	.95	0
8	5	.88	.04	.03	.90	.01	.00	.94	.01
8	10	.85	.07	.05	.87	.04	.02	.93	.02
8	15	.83	.09	.06	.86	.05	.02	.92	.03
8	20	.80	.12	.09	.85	.06	.03	.92	.03
8	25	.77	.15	.12	.84	.07	.04	.92	.03
8	30	.74	.18	.14	.82	.09	.05	.91	.04

These are my results of the experiment.
My results show that in the colder water, the peas had a much lower difference than in the room temperature water. It also showed that as time went on the difference grew, although not as consistent as expected. Lastly, it showed that the germinating peas had a higher difference than the dry peas, as my hypothesis predicted.

Enzyme Lab 8/26/11

My partner for this lab was Ariel.  The purpose of the lab was to test how much oxygen was produced by the enzyme, which in this case was yeast.

The setup for this lab involve a graduated cylinder filled with water and submerged partly underwater upside down. It was submerged in a tub of water. Our reaction chamber was filled with 20 milliLiters of peroxide and plugged with a stopper with a hole in it. In the hole was a rubber tube that was placed in the opening of the graduated cylinder.

Once the set-up was complete, our testing began. We started with one milliLiter of the yeast solution and added it to the reaction chamber and quickly put the stopper in. The second and third tests were the same except for the amount of yeast solution. The second used .75 milliLiters and the third used .5 milliLiters.

Our results for the first test showed that the enzyme produced very little oxygen in the beginning. After recording every 30 seconds for 5 minutes, our results increased and the oxygen bubbles were larger and more frequent. It produced almost 15 milliLiters of oxygen in the end.

Our second and third test's results were similar, starting off slow but gradually increasing in the amount of oxygen. The second test produced a smaller amount of oxygen than the first test. The third test was similar in producing a smaller amount of oxygen than the first and second. However, the results showed that it produced hardly any oxygen at all and only created many very small bubbles instead of a few large bubbles like the other tests.

Based on these results, our conclusion is that the smaller amount of yeast in the solution, the less reaction it will have. It produces less oxygen with each decreasing amount. We believe that some inconsistencies may have been caused due to the amount of peroxide we put in the reaction chamber and the setup. Our very first trial had to be re-done because the stopper popped out of the chamber. Therefore, the results may be inconclusive, but the theory remains the same and valid.

Rolly Polly Lab 8/11/10

This lab assignment consisted of collecting rolly pollys or pillbugs from each students yard.  We then experimented on the creatures by testing different hypothesis's about their habitats and environments.

My group was with Ariel and Dara.  We wanted to test the moisture of the rolly polly's habitat and what drew them to the enviroments we discovered them in.  Our hypothesis was that since the bugs were found underneath rocks and logs that they would prefer a moist habitat rather than a dry one.

To test this hypothesis we used habitat trays with two sections to compare to each other.  We used two pieces of paper, one dry and one wet with tap water.  We then placed 14 rolly pollys in the tray and waited approximately 10 minutes before beginning the test in order to let the bugs adapt to the new environment somewhat.  This would allow them to try out both habitats and then make a decision.  Our group then started recording data every minute, writing down how many bugs were in each habitat. 

The first minute of data we recorded showed that all of the bugs prefered the dry habitat.  However, the next couple minutes showed a split decision with about 9 or 8 bugs on the dry side and 5 or 6 on the wet.  This data confused our group, but as we watched longer, we recorded data that stated that the bugs prefered the dry side the rest of the time. 

During this experiment, we noticed that the rolly pollys grouped together with each other, almost as if they were huddling together to stay warm and sleeping.  Because of this analization, our group believes that it is not the moisture of the environment that the bugs prefer, but rather the temperature or darkness.  However, we ran out of time so we could not test either of these new hypotheses.