To examine the effects of various physio-chemical treatments upon the permeability of beetroot cells.

Apparatus:

Take care using a cork borer.

•  Cork borer
• White tile
• Knife
• Pens
• Ruler
• Water baths at 20, 40, 60, 80oC
• Measuring Cylinder
• 2 boiling tube racks
• Crushed ice
• 8 boiling tubes
• Thermometer (one per water bath)
•  Colorimeter
• Cuvettes
• Stopclock
• Distilled water
• Pipette for measuring 2 cm3

Variables: There are different types of Variables, there are:

1. Controlled Variable
2. Dependent Variable

Controlled Variable:

• Temperature

Dependent Variable:

• Time

Fair Testing:

During the preparation of the beetroot experiment, I was able to an extra 5 pieces as a control Variable, giving me the choice of the 10 reliable looking beetroot pieces of about 1cm. I was able to do this because of the extra space from the beetroot that I was able to gain more uniform cylinders.

Whilst actually cutting the beetroot pieces, I discovered that it was easier for me to cut out the pieces into the required length after having cut each uniform cylinder.

Method: As shown in the worksheet given by Mr Cliff

Results: My Results show a good progression in the trend of results,

                                        (As Shown in the Graph)

Accuracy of test:

        The accuracy of the experiment will be affect by certain factors such as these:

1. Error and uncertainty of the timing of the Minute e.g.  
2. Uncertainty of the measuring of the Beetroot
3. Adjustments made to the timing of the beetroot in the deionised water, (26mins)

Conclusion:

At 5oc, there’s a slight decrease in the average percentage of transmission from 100%. This is because when water freezes, it expands and this makes the cell membrane bursts. The bursting results in more pigments leaking out and the darker the colour of the liquid obtained.

Between 40ºC and 60ºC, proteins are denaturing more and more as the temperature increases. This is lowering the percentage of transmission as more pigments are leaking out due to the denatured proteins and the lower the transmission (the darker the colour).

By 80ºC most of the proteins have already denatured and this explains the steep slope on the graph. By that temperature, most colours has already leaked out and therefore resulting in the highest transmission

Interpretation: The overall trend seems to be that as the temperature increases, the percentage of transmission decreases expect for the exceptional anomaly which is 200c (Room Temperature). This is suggesting that membrane permeability increases with temperature expect for one exception and therefore more colour leaks out. The darker the colour means that more pigments have leaked out and therefore the lower percentage of transmission

Evaluation:

• The size of the borer used, will affect the amount of betacyanin in the cylindrical beetroot therefore that will affect the result.

Improvements:

• The
• The amount of times the experiment was repeated.
• The fluctuation temperature of the actual water bath could have been kept at the authentic temperature.

.

.