( ( Passive ( Transport ( Passive transport ) ) ) ( ( occurs ( when ( substances ( ( ( cross ( the ( plasma membrane ) ) ) ( without ( ( any input ) ( of energy ) ) ) ) ( from ( the cell ) ) ) ) ) ) . ) )
(ROOT (S (NP (NNP Passive) (NNP Transport) (NNP Passive) (NN transport)) (VP (VBZ occurs) (SBAR (WHADVP (WRB when)) (S (NP (NNS substances)) (VP (VBP cross) (NP (DT the) (NN plasma) (NN membrane)) (PP (IN without) (NP (NP (DT any) (NN input)) (PP (IN of) (NP (NN energy))))) (PP (IN from) (NP (DT the) (NN cell))))))) (. .)))
Passive Transport   Passive transport occurs when substances cross the plasma membrane without any input of energy from  the cell.
(ROOT (S (SBAR (WHADVP (WRB When)) (S (NP (NNS substances)) (VP (VBP pass) (PP (IN through) (NP (DT the) (NN cell) (NN membrane))) (PP (IN without) (S (VP (VBG needing) (NP (DT any) (NN energy)))))))) (, ,) (NP (PRP it)) (VP (VBZ is) (VP (VBN called) (NP (JJ passive) (NN transport)))) (. .)))