( ( ( ( ( ( ( The resistance ) ( of ( ( a ( pure ( lipid bilayer ) ) ) ( to ( ( the passage ) ( of ( ions ( across it ) ) ) ) ) ) ) ) ( is ( very high ) ) ) , ) but ) ( ( structures ( embedded ( in ( the membrane ) ) ) ) ( ( can greatly ) ( ( ( ( ( ( enhance ( ion movement ) ) , ) either ) ( ( actively or ) passively ) ) , ) ( via ( mechanisms ( called ( ( ( facilitated transport ) and ) ( facilitated diffusion ) ) ) ) ) ) ) ) ) . )
(ROOT (S (S (NP (NP (DT The) (NN resistance)) (PP (IN of) (NP (NP (DT a) (JJ pure) (NN lipid) (NN bilayer)) (PP (TO to) (NP (NP (DT the) (NN passage)) (PP (IN of) (NP (NP (NNS ions)) (PP (IN across) (NP (PRP it)))))))))) (VP (VBZ is) (ADJP (RB very) (JJ high)))) (, ,) (CC but) (S (NP (NP (NNS structures)) (VP (VBN embedded) (PP (IN in) (NP (DT the) (NN membrane))))) (VP (MD can) (ADVP (RB greatly)) (VP (VP (VB enhance) (NP (NN ion) (NN movement))) (, ,) (CC either) (ADVP (ADVP (RB actively)) (CC or) (ADVP (RB passively))) (, ,) (PP (IN via) (NP (NP (NNS mechanisms)) (VP (VBN called) (NP (NP (JJ facilitated) (NN transport)) (CC and) (NP (JJ facilitated) (NN diffusion))))))))) (. .)))
The resistance of a pure lipid bilayer to the passage of ions across it is very high, but structures embedded in the membrane can greatly enhance ion movement, either actively or passively, via mechanisms called facilitated transport and facilitated diffusion.
(ROOT (S (NP (PRP You)) (VP (VBP call) (NP (NP (DT the) (NN movement)) (PP (IN of) (NP (NP (NNS molecules)) (PP (IN across) (NP (DT a) (ADJP (JJ membrane) (PP (IN without) (NP (NP (DT the) (NN input)) (PP (IN of) (NP (NN energy)))))) (JJ passive) (NN transport))))))) (. .)))