( ( Receptor ( and ( ion channels ) ) ) ( ( ( are closely ) ( associated ( in ( the membrane ) ) ) ) . ) )
(ROOT (S (NP (NN Receptor) (CC and) (NN ion) (NNS channels)) (VP (VBP are) (ADVP (RB closely)) (VP (VBN associated) (PP (IN in) (NP (DT the) (NN membrane))))) (. .)))
Receptor and ion channels are closely associated in the membrane.
(ROOT (NP (NP (NP (NNP Ion) (NNP channels) (NNP facilitate)) (PRN (-LRB- -LRB-) (PRP s) (-RRB- -RRB-))) (NP (NP (DT the) (NN diffusion)) (PP (IN of) (NP (NP (NNS ions)) (PP (IN across) (NP (DT a) (NN membrane)))))) (. .)))