( ( The promastigotes ) ( ( are ( ( slender ( , ( spindle-shaped cells ) ) ) ( with ( ( a ( single flagellum ) ) ( that ( ( endows them ) ( with motility ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (DT The) (NNS promastigotes)) (VP (VBP are) (NP (NP (JJ slender) (, ,) (JJ spindle-shaped) (NNS cells)) (PP (IN with) (NP (NP (DT a) (JJ single) (NN flagellum)) (SBAR (WHNP (WDT that)) (S (VP (VBZ endows) (NP (PRP them)) (PP (IN with) (NP (NN motility)))))))))) (. .)))
The promastigotes are slender, spindle-shaped cells with a single flagellum that endows them with 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))))))) (. .)))