( ( Phospholipids ( that ( are ( ( principal components ) ( of cell ) ) ) ) ) ( membranes . ) )
(ROOT (S (NP (NP (NNS Phospholipids)) (SBAR (WHNP (WDT that)) (S (VP (VBP are) (NP (NP (JJ principal) (NNS components)) (PP (IN of) (NP (NN cell)))))))) (VP (VBZ membranes)) (. .)))
Phospholipids that are principal components of cell membranes.
(ROOT (S (NP (NNS Phospholipids)) (VP (VBP are) (NP (NP (DT the) (JJ main) (NN component)) (PP (IN of) (NP (DT the) (NN cell) (NN membrane))))) (. .)))