What is a Phospholipid? by John O’ Connor Phospholipids are a
special subgroup of lipids that are essential to human health.
Although important for a number of cell functions, their most
vital role is determining the structure of the cell membrane.
Generally composed of a hydrophilic (“water-loving”) head and
hydro-phobic (“water-fearing”) fatty acid tail, phospholipids
are naturally amphipathic, meaning that these molecules have two
different affinities as indicated. Each phospholipid slightly
varies in structure, but its hydrophilic head generally contains
a small molecule bound to a phosphate group, which is attached
to glycerol. Glycerol (C3H8O3) is a trihydroxy sugar alcohol
that forms the backbone of many lipids. In phospholipids,
glycerol is bound to two fatty acid chains that compose the
hydrophobic tail. A cell membrane is a physical barrier composed
of a phospholipid bilayer, which consists of two layers of
phospholipids that separate the inside of the cell from the
outside. Supporting a well-known