( ( Carrier proteins ) ( ( are ( ( important ( for ( transport ( of ( ( many types ) ( of ( substances ( across ( both ( external ( and ( internal cell ) ) ) ) ) ) ) ) ) ) ) ) ( ( membranes -LRB- ) fig ) ) ) . ) )
(ROOT (S (NP (NN Carrier) (NNS proteins)) (VP (VBP are) (VP (ADVP (JJ important) (PP (IN for) (NP (NP (NN transport)) (PP (IN of) (NP (NP (JJ many) (NNS types)) (PP (IN of) (NP (NP (NNS substances)) (PP (IN across) (NP (DT both) (JJ external) (CC and) (JJ internal) (NN cell)))))))))) (VBN membranes) (-LRB- -LRB-) (NP (NN fig)))) (. .)))
Carrier proteins are important for transport of many types of substances across both external and internal cell membranes (fig.
(ROOT (S (NP (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))))))) (. .)))