Describe the structure of a phospholipid.

I assume you mean phospholipid bi-layer. It looks like this

The phospholipids comprise two alcohols, a phosphate group, and one or two fatty acids. On one terminal of the molecule, one alcohol and the phosphate group is present, and this terminal is considered as polar, that is, exhibiting an electric charge and is fascinated towards the molecules of water. While the other terminal comprises fatty acids, it is neutral and is hydrophobic, water-insoluble.

Thus, phospholipid possesses amphipathic nature, which makes them an essential component of the membrane, as they produce a two-layer composition known as the lipid bilayer.