Essay on Effect of Ethanol on Beetroot Membrane

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Biology Coursework

Hypothesis: To investigate the effect of different concentrations of ethanol on the permeability of beetroot cell membranes.

Prediction: By exposing a membrane to a solvent, ethanol, it will increase its permeability. So the higher the concentration of the solvent, the more permeable the membrane will be. But if the concentration of the ethanol is beyond a certain limit, it may break down the cell membrane to the point where there is in fact no overall effect as the ethanol would disturb the lipids in the membrane.

Therefore, more of the red pigment in the beetroot would leak as the lipids control the substances that enter and leave the cell membrane.

However the ethanol might also impair particular …show more content…

When beetroot is sliced or cut, the cells are also sliced, causing the pigment to spill out. The thinner the slices are, the larger the surface area, which would increase the rate of pigment leakage. But if the membrane is destroyed and the phospholipid bilayer and are changed, more pigment, betacyanin leaks by means of diffusion.

The basic structure of betacyanins

Betalaines are the red pigments of beetroot. They are water-soluble and exist as internal salts in the sap vacuoles of plant cells. Betalaines are made up of red betacyanins and yellow betaxanthins. Betacyanines include about 90% of beetroot betalaines. The most important betacyanin is betain. This makes up 75-95% of the total colouring found in the beetroot. Jm
C2H5OH :


Generally ethanol is an alcohol found in alcoholic drinks. At 100% concentration, it is pure and a colourless liquid with a strong odour (due to weak Van der Wall forces :D. Ethanol is produced by the fermentation of carbohydrates in yeast cells and is used frequently as a solvent.

Proteins which make up about 70% of cell membranes are affected by the pH of ethanol. Proteins are made of amino-acids which can form hydrogen bonds with the many hydrogen atoms found in the molecule.

The position of some of these hydrogen atoms formed change when the pH of a solution changes.
Therefore the shape of the protein molecule alters due to the change in pH.

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