So the major difference between this structure and this structure is that this structure actually consists of two different layers. So two phosphol lipid layers, one and two. And each one of these sides, each one of these layers is known as a leaflet. So in this double layer we have the polar heads orient themselves towards the aqueous environment while the nonpolar tails aggregate on the inside to form a barrier, the hydrophobic barrier. So the interior of the cell membrane. The lipid bilayer is hydrophobic because it consists predominantly of these tails, while the outside and the inside portion of this bilayer consists of these heads.