The bilayer of phospholipid molecules composes the major stuff of the plasma membrane, and the polar ends of phospholipid (that look similar to a cluster of the balls in an interpretation model of an artisan) are in an association with watery fluid both in and out of the cell. As a consequence, both the planes of the plasma membrane are hydrophilic (water-loving) but in contrast, on the inside of the membrane, in the midst of its two planes, is a hydrophobic (water-fearing) or a non-polar section due to the fatty acid tails, this section or region do not have any attraction for polar molecules or water.

A particle of phospholipid is comprised of the backbone of three-carbon glycerol in the company of two fatty acid particles bound to 1 and 2 carbons and a group that possesses phosphate attached to carbon 3. Such an organization provides the entire molecule with an area illustrated as its head (a group that contains phosphate), that possesses a negative charge or a polar nature, and a portion called a tail with no charge (the fatty acids). The tail cannot form hydrogen bonds, but the head can make hydrogen bonding.