Phospholipids are amphipathic molecules. This means that they have a hydrophilic, polar phosphate head and two hydrophobic fatty acid tails. These components of the phospholipids cause them to orientate themselves, so the phosphate head can interact with water and the fatty acid tails can't, hence forming a bilayer.
Likewise, is lipid hydrophilic or hydrophobic?
Lipids are fats, like oil, that are insoluble in water. There are two important regions of a lipid that provide the structure of the lipid bilayer. Each lipid molecule contains a hydrophilic region, also called a polar head region, and a hydrophobic, or nonpolar tail region.
What do the hydrophobic tails do?
In biological systems, the phospholipids often occur with other molecules (e.g., proteins, glycolipids, sterols) in a bilayer such as a cell membrane. Lipid bilayers occur when hydrophobic tails line up against one another, forming a membrane of hydrophilic heads on both sides facing the water.