( ( ( The function ) ( of ( a ( bacterial flagellum ) ) ) ) ( ( ( is ( ( -LRB- ( a -RRB- ) ) cell ) ) motility ) . ) )
(ROOT (S (NP (NP (DT The) (NN function)) (PP (IN of) (NP (DT a) (JJ bacterial) (NN flagellum)))) (VP (VBZ is) (NP (PRN (-LRB- -LRB-) (X (SYM a)) (-RRB- -RRB-)) (NNS cell)) (ADVP (RB motility))) (. .)))
The function of a bacterial flagellum is (a) cell motility.
(ROOT (S (PP (IN In) (NP (NNS humans))) (, ,) (NP (DT the) (NN sperm) (NN cell)) (VP (VBZ is) (NP (NP (DT the) (JJ only) (NN cell)) (PP (IN with) (NP (DT the) (NN flagella) (NN structure))) (SBAR (WHNP (WDT that)) (S (VP (VBZ enables) (ADVP (RB motility))))))) (. .)))