The effect of temperature on beetroot membranes

Independent variable

The variable to be adjusted is the temperature and will be adjusted by using water baths of different temperatures to put the test tubes in.

Dependent variable

The results will be measured by a colorimeter which will measure the absorbency of the liquid to show how much beetroot has leaked out.

We repeated the experiments until we found concordant results as it means results will be more reliable, and will make sure that none of our results are anomalous. If there are any anomalies, we can discard them which will ensure concordancy. However, we didn’t repeat the experiments for every temperature, so our results might not be reliable.

We collected everyone else’s results and compared them with ours to see how concordant they were. There is an anomaly at 10 degrees C where Sophie’s results give 113%T at 430nm however everyone else got no higher than 91 at this temperature.We also got an anomaly at 70 degrees C, 25%T at 430nm when everyone else’s results give between 10-13%T at 430nm. They could be a systemic error if the colorimeter was not calibrated correctly and settings were not set correctly at 0 absorbance for clear water or if the control reading was not taken meaning our results weren’t concordant.

Conclusions (C1)

My results mostly agree with my original hypothesis that the higher the temperature the more pigment will leak from the beetroot and therefore there will be a higher absorbance of light. However, we did get some anomalies due to random and systematic errors.

This is because as the temperature increases so does the amount of kinetic energy which will denature the proteins embedded in the phospholipid bilayer. This allows the pigment in the beetroot to diffuse out of the membrane through osmosis where the proteins have been denatured.

Two of our results are anomalous, our reading of 93 %T at 430nm at 0 degrees C, and our reading of 25 %T at 430nm at 70 degrees C. These anomalies are probably due to a random error, such as taking down the reading incorrectly by mistake. Also, from the classes average results our results for 60, 70 and 80 degrees C were the wrong way round as to what I’d predicted in my hypothesis because we thought the higher the temperature the higher the absorbency would be. This is probably due to the fact that its a class average and there would be slight variations between groups on how the experiment was carried out.