( ( Animal cells ) ( ( lack ( ( the ( cellulose ( cells walls ) ) ) ( of ( plant cells ) ) ) ) . ) )
(ROOT (S (NP (NNP Animal) (NNS cells)) (VP (VBP lack) (NP (NP (DT the) (NN cellulose) (NNS cells) (NNS walls)) (PP (IN of) (NP (NN plant) (NNS cells))))) (. .)))
Animal cells lack the cellulose cells walls of plant cells.
(ROOT (S (NP (DT A) (NN cell) (NN wall)) (VP (VBZ is) (VP (VBN found) (PP (PP (IN in) (NP (DT a) (NN plant) (NN cell))) (CONJP (CC but) (RB not)) (PP (IN in) (NP (DT an) (NN animal) (NN cell)))))) (. .)))
A cell wall is found in a plant cell but not in an animal cell.