( Thylakoids ( ( consist ( of ( ( a ( thylakoid membrane ) ) ( surrounding ( a ( thylakoid lumen ) ) ) ) ) ) . ) )
(ROOT (S (NP (NNS Thylakoids)) (VP (VBP consist) (PP (IN of) (NP (NP (DT a) (JJ thylakoid) (NN membrane)) (VP (VBG surrounding) (NP (DT a) (JJ thylakoid) (NN lumen)))))) (. .)))
Thylakoids consist of a thylakoid membrane surrounding a thylakoid lumen.
(ROOT (S (NP (DT The) (JJ light) (NNS reactions)) (VP (VBP take) (NP (NP (NN place)) (PP (IN in) (NP (DT the) (NN thylakoid))))) (. .)))