Lab Report: Cell Respiration

Abstract: In this lab, we tested if/how temperature affects the rate of cell respiration.  We used yeast -adding sucrose, warm water, and salt to induce cell respiration - and testing 3 different vials, each at different temperatures. Attached to each vial was a syringe and tubing used to check how much carbon dioxide was released through cell respiration. Although several factors affected the results of our experiment, our results showed that an increase in temperature initially increased the rate of cell respiration.

Introduction: In cell respiration, chemical energy from glucose is transferred into ATP.
The glucose is converted to ATP through a series of three steps called Glycolysis, The Krebs Cycle, and the Electron Transport System.  The formula for cellular respiration is C6H12O6 + 6O2 --> 6H2O + 6CO2 + ATP. This lab is designed to measure the CO2 produced from this reaction in order to proportionately measure the rate of cellular respiration.

Hypothesis: Compared to the control test tube at room temperature, the heated test tube will produce more CO2 and thus have a higher respiration rate, because at a higher temperature there is higher molecular movement that would increased the reaction rate. Accordingly, the chilled test tube will produce less CO2 and have a slower respiration rate, because at lower temperature there is slower molecular movment.

Materials:  

1. 105 mL warm water
2. 3g yeast
3. 3g sucrose
4. 0.3g salt
5. Beaker
6. Hot plate
7. Ice bucket
8. Scale
9. Stopwatch
10. 3 vials
11. 3 syringes
12. Graduated cylinder

Procedure:

1. Pour 35mL of water into each of the 3 vials.
2. Add 1.0g sucrose into each vial.
3. Add 0.1g salt into each vial.
4. Cover, shake, and then uncover each vial. Let them sit for 5 minutes.
5. Plug each tube with the stoppers attached to the syringes. 
6. Pull up each syringe to the 2mL mark.
7. Place each vial in their respective temperature conditions and start the stopwatch.
8. Record the new volume of CO2 in the syringe after every minute. After every recording, lightly press the syringe down.
9. Graph data.

Results: 

Conclusion:

     

     Our experimental results supported our hypothesis completely. The yeast in the heated vial produced the most  CO2 and therefore had the highest respiration rate. Conversely, the yeast in the chilled vial produced the least CO2 and had the lowest respiration rate. Although these results were what was expected, several sources of error might have affected our experimental results. The most prominent error was that the heated vial exploded and overflowed in the early part of the experiment. Therefore the CO2 volume readings are inaccurate, but should be around the correct range. Another source of error came from difficulty using the syringes and getting them to come back up after pressing down after each reading. 

Works Cited:

 Quick, Kevin, Holly, Kiamanesh, Rosie Montague, Jennifer Blanchette, and Barbara Akre. The Webb Schools Honors Biology Textbook. Claremont; CK-12 Foundation, 2012. eBook.