When one oxygen is replaced by a phosphate group, this becomes a glycerophospholipid or phosphoglyceride. Fatty acids are the simplest lipids, made from a hdyrophobic carbon chain and a carboxylate group. Most common phospholipids are diacylglycerides , are built from the glycerol backbone and two fatty acids. If only one fatty acid chain is present, it becomes a monoacylglyceride . Phospholipids with one fatty acid chain are also known as lysophospholipids.
Many phospholipids have additions to the phosphate group, creating distinct headgroups .