( ( This structure ) ( ( plays ( ( an ( important role ) ) ( in ( aerobic respiration ) ) ) ) . ) )
(ROOT (S (NP (DT This) (NN structure)) (VP (VBZ plays) (NP (NP (DT an) (JJ important) (NN role)) (PP (IN in) (NP (JJ aerobic) (NN respiration))))) (. .)))
This structure plays an important role in aerobic respiration.
(ROOT (S (NP (NP (DT The) (NN structure)) (PP (IN of) (NP (NN mitochondrion)))) (VP (VBZ plays) (NP (NP (DT an) (JJ important) (NN role)) (PP (IN in) (NP (JJ aerobic) (NN respiration))))) (. .)))