Cpac 2: Beetroot

Question 1

Ethanol concentration effect on membrane

Answer 1

Ethanol causes the cell-surface membrane to rupture, releasing the betalain pigment from the cell. Higher concentrations of ethanol will cause more disruption to the membrane and more gaps will form. Thus, as concentration of ethanol increases, the permeability of cell-surface membrane also increases.

Question 2

method

Answer 2

1. Cut beetroot into 8 ​identical cylinders​ using a cork borer and wipe/rinse to clean off any pigment​ released as a result.
2. Place each of the cylinders of beetroot in 10 ml of distilled water. Place each test tube in a ​water bath​ at a ​range of temperatures ​between​ ​0 and 70​°​C.
3. Leave the samples for ​15​ minutes​- pigment will leak out of the beetroot.
4. Record the exact temperature of the ​water bath ​using the thermometer.
5. Remove the test tubes from the water baths and remove the cylinders of beetroot
   from them. Decant the liquid into clean test tubes.
6. Set the colorimeter to a ​blue filter​ and​ zero​ using a cuvette with ​distilled water​.
   Filter each sample into a cuvette using ​filter paper​.
7. Measure the ​absorbance​ for each solution. A ​higher absorbance​ indicates higher pigment concentration​, and hence a ​more permeable membrane​.