Phospholipid fatty acids may be redistributed after they are synthesized in response to varying environmental conditions or needs.

Phospholipases are enzymes that can catalyze cleavage of acyl or phosphoacyl moieties from glycerophospholipids, as shown in Figure 19.6. Phospholipases are implicated in rearrangement of phospholipids after they have been synthesized and in release of arachidonic acid from glycerophospholipids in eicosanoid metabolism.