Levels of Organization Image Map
Step 2: Get the Lipids Out  

Lipids are a major component of cells. Lipids can be separated from many proteins rather easily, because lipid does not dissolve well in water. Lipid removal is desired before protein purification processing, because lipids would interfere with the separation of the different kinds of proteins.

Separation of the lipid from the protein can be done by first gently mashing the cells to make their lipids and proteins. Then, the cellular debris  is stirred into a mixture of two different solvent 
that do not dissolve in each other. The mashing does not break the basic atomic bonding in lipids and proteins, so proteins can be recovered intact from the solvent that contains the protein. The solvent with the lipid fraction can be thrown away. 

This would be a good time to perform activity #1, if it fits with the class schedule.

Fats tend to self organize like this in water, rather than dissolving.  But they do dissolve in organic solvents, whereas proteins do not.

extraction2.USDA.jpg (5906 bytes)
U.S. Department of Agriculture scientist extracting cellular components