( ( A mitochondrion ) ( ( contains ( ( two ( main membranes ) ) ( composed ( of ( phosopholipid ( ( bilayers and ) proteins ) ) ) ) ) ) - ) )
(ROOT (S (NP (DT A) (NN mitochondrion)) (VP (VBZ contains) (NP (NP (CD two) (JJ main) (NNS membranes)) (VP (VBN composed) (PP (IN of) (NP (JJ phosopholipid) (NNS bilayers) (CC and) (NNS proteins)))))) (: -)))
A mitochondrion contains two main membranes composed of phosopholipid bilayers and proteins -
(ROOT (S (NP (CD Two) (NNS membranes)) (VP (VBP form) (NP (NP (DT the) (NN mitochondrion) (NN structure)) (PP (IN of) (NP (DT a) (NN cell))))) (. .)))