The polar end of the phospholipid molecule, which contains a phosphate group and an alcohol, is attracted to water, or hydrophillic, and water-soluble. The opposite end of the phospholipid contains the fatty acids, which are non-polar, water-insoluble and hydrophobic.
Due to the presence of both water-soluble and water-insoluble groups, phospholipids are termed amphipathic. They make up the biological membrane of the cell, each side interacting with a different environment based on its properties. The polar and water-soluble end faces the external part of the cell where water is located with the non-polar, water-insoluble region points toward the interior portion of the membrane.