Since you asked… Soap!

A student in Principles of Biology asked a question today that I didn’t know the answer to – are phospholipids the molecules in soap that facilitate its ability to dissolve both polar (carbohydrates, nucleic acids, and some proteins) and nonpolar (lipids and some proteins) materials?

The short answer: Nope! Soaps aren’t using any of the 3 major types of lipids, it’s a modified single fatty acid chain.

The longer answer: Sodium salt and potassium salt versions of fatty acids are the main active component of soaps. In fact the process of saponification serves primarily to separate the glycerol backbone from the fatty acid chains. This process results ionized chains in the solution, which then form ionic bonds with Na+ or K+ ions when salts are added to the mixture.

E.g. Sodium oleate: 

Salt form, found in soap

Comes from lipids containing oleic acid

1200px-oleic-acid-based-on-xtal-1997-2d-skeletal

Fatty acid form, found in phospholipids or triglycerides

Cheers for science & research!

 

The book-length answer: 
https://en.wikibooks.org/wiki/Structural_Biochemistry/Lipids/Soap

Advertisements