Investigation into the effect of concentration of copper (II) sulphate on the denaturation of egg albumen
The aim of this experiment is to investigate the lowest concentration of copper (II) sulphate that will bring about the full denaturation of egg albumen. I will achieve this by diluting 0.1 mol dm3 copper (II) sulphate ten times to acquire 10 consecutively more dilute solutions. These will then be added to the same volume of egg albumen. The experiments will be performed at room temperature and the extent of denaturation will be decided on the ‘opaqueness’ of the albumen.
Prediction
I predict that the lowest concentration of copper (II) sulphate will be around 0.01 – 0.02M. This is because of the following reason. Copper ions in copper (II) sulphate are highly electropositive. Within proteins exist ionic bonds, which form between amine and carboxylic terminals resulting in polarised R groups. Due to the high positive charge of the Cu2+ ions, when copper ions are in the presence of the R groups, they are pulled toward the negatively charged R groups. The copper ion then forms an ionic bond with the polarised R group, which is stronger than the already existing bond. As a result, the existing bonds are broken and the protein changes shape. This change in shape is responsible for the denaturation. At a lower concentration of copper (II) ions (smaller overall concentration), there will be less R groups disrupted as all the copper ions would have bonded with R groups. These would leave other proteins unaffected, which would result in only partial denaturation. This hypothesis is the reason for my prediction.