Page "Biochemistry" Paragraph 46

Most lipids have some polar character in addition to being largely nonpolar.

In general, the bulk of their structure is nonpolar or hydrophobic (" water-fearing "), meaning that it does not interact well with polar solvents like water.

Another part of their structure is polar or hydrophilic (" water-loving ") and will tend to associate with polar solvents like water.

This makes them amphiphilic molecules ( having both hydrophobic and hydrophilic portions ).

In the case of cholesterol, the polar group is a mere-OH ( hydroxyl or alcohol ).

In the case of phospholipids, the polar groups are considerably larger and more polar, as described below.