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The emulsion test- causes a white cloudy colour when lipid is dissolved in ethanol and then water added. Can this be used for phospholipids? I am aware that they are polar so may arrange in a circular formation in water but would the test still work?

Thanks

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Yes, the test will still work. And you are correct about the phospholipid's process of forming 'circles' in water. The reason the test still works is because alcohol increases the permeability of the edge of these circles by making them less structurally stable. This then allows the ethanol to enter.

The hydrophilic phosphate head is not soluble in alcohol as it is not a lipid, but after the alcohol can bypass these heads, they can interact with the inner hydrophobic 'tails', which are soluble. The white emulsion/layer will then form.

This can be seen in the experiment of using alcohols to test the permeability of cell membranes. -See this investigation carried out by Westminster College.

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