Stress and Cellular Membranes

Topics: Solvent, Cell membrane, Temperature Pages: 6 (1473 words) Published: October 20, 2010
Stress and Cellular Membranes
Bio Lab

Due: Sept 24th, 2010
For: Ms. Barton
By: Ameema Saeed
(See attached lab)

(See attached lab)

Tap water will cause no damage to the membranes. The extreme temperatures of the water cooled to 0°C, and heated to 94-100°C will greatly damage the membranes. Extreme heat will be more damaging than extreme cold.

The more concentrated the solvent, the more damage it will cause to the membranes, therefore the solvent of 50% Acetone, and the solvent of 50% Methanol will have higher readings of damage than the solvents of 25% Acetone, and 25% Methanol.

(See attached lab)

(See attached lab)


Temperature Lab
| |Quantitative results |Qualitative results | |Room temperature tap water |0.045 |Water is exactly the same. | |60˚ C water |0.313 |Water is dark Pink. | |Boiling water (94˚ C-100˚ C) |0.520 |Water is darkest Pink, Beet is soft and mushy. | |Cold water (0˚ C) |0.267 |Water is dark Pink, close in colour to the 60˚ Beet. Beet looks | | | |less damaged. |

Solvent-related Treatment lab
| |Quantitative results |Qualitative results | |Regular tap water |0.038 |Water is exactly the same. | |25% Acetone |0.061 |Water is slightly changed in colour—light Pink. | |50% Acetone |0.297 |Water is completely Pink, and changed colours quickly. | |25% Methanol |0.080 |Water is light Pink, Beet appears damaged. | |50% Methanol |0.078 |Minimal Pink in the water, Beet appears to be decomposing. |

Data Analysis:
1. The individual results, as well as the results compiled with information from other groups supported the hypotheses concerning temperature, and membrane damage, showing that extreme heat is more damaging than extreme cold. The treatment that most damaged the membranes was the one with the boiling water and the least damaging—aside from tap water—was the freezing water. The individual results and the compiled results were similar, in regards to the solvent polarity and the membrane damage as well. However, whether it was due to human error, equipment error, or whether it was supposed to happen, the Acetone supported the hypothesis, but the Methanol did not. The membrane damage of both the 25% and the 50% Methanol solutions were very close.

2. In the temperature lab, the boiling water treatment damaged the membranes the most, and the freezing water damaged them the least, aside from the room-temperature. In the solvent lab, the 50% Acetone damaged membranes the most, while the 25% Acetone damaged them the least.

3. In general, extreme heat is more damaging to membranes than extreme cold. This is because the membranes underwent the process of denaturation, which is caused by heat. Denaturation is caused by pressure applied to the membranes, due to the extreme heat, which results in the membrane losing its resilience (Yang). When a membrane loses its resilience, and is “denatured”, it loses whatever substance is inside it; which is why the beet leaked colour. Also, as temperature and Kinetic energy increase, the rate of diffusion...

Bibliography: - Andrews, C. J. (1996). How do plants survive ice? Annals of Botany, 78. Retrieved from
-Class notes
-Hunt, I. Lipids. University of Calgary- Chemistry. Retrieved September 23, 2010, from
-Yang, W. H., Cenkowski, S., & Wang, H.S. (1996). Microwave-enhanced denaturation of sugar beet tissues. American Society of Agricultural and Biological Engineers Technical Library. Retrieved from
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