Number two is fatty acids are actually used to build molecules that exist within cell membranes. So things like lycolipids and phospholipids are built from fatty acids. Number three is we can modify proteins by attaching fatty acids onto them. And what this does is it increases and diversifies the functionality of the proteins. Number four is molecules such as hormones and other intracellular messenger molecules are built from fatty acids. So we have many hormones which are built from fatty acids.