( ( ( The ( complex ( biochemical reactions ) ) ) ( that ( form ( ( the metabolism ) ( of ( living organisms ) ) ) ) ) ) ( ( are ( ( ( regulated ( by ( thousands ( of enzymes ) ) ) ) , ) ( each ( ( promoting ( ( a ( specific reaction ) ) ( that ( takes place ) ) ) ) ( ( countless times ) ( every day ) ) ) ) ) ) . ) )
(ROOT (S (NP (NP (DT The) (JJ complex) (JJ biochemical) (NNS reactions)) (SBAR (WHNP (WDT that)) (S (VP (VBP form) (NP (NP (DT the) (NN metabolism)) (PP (IN of) (NP (VBG living) (NNS organisms)))))))) (VP (VBP are) (VP (VP (VBN regulated) (PP (IN by) (NP (NP (NNS thousands)) (PP (IN of) (NP (NNS enzymes)))))) (, ,) (NP (NP (DT each)) (VP (VBG promoting) (NP (NP (DT a) (JJ specific) (NN reaction)) (SBAR (WHNP (WDT that)) (S (VP (VBZ takes) (NP (NN place)))))) (NP (NP (JJ countless) (NNS times)) (NP (DT every) (NN day))))))) (. .)))
The complex biochemical reactions that form the metabolism of living organisms are regulated by thousands of enzymes, each promoting a specific reaction that takes place countless times every day.
(ROOT (S (NP (JJ Biochemical) (NNS reactions)) (VP (VBP take) (NP (NP (NN place)) (PP (IN inside) (NP (NP (DT the) (NNS organisms) (POS ')) (NNS cells))))) (. .)))