( Metabolism ( ( is ( ( the ( sum total ) ) ( of ( ( all ( the ( chemical reactions ) ) ) ( occurring ( in ( ( an organism ) ( at ( any ( given time ) ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NNP Metabolism)) (VP (VBZ is) (NP (NP (DT the) (NN sum) (NN total)) (PP (IN of) (NP (NP (PDT all) (DT the) (NN chemical) (NNS reactions)) (VP (VBG occurring) (PP (IN in) (NP (NP (DT an) (NN organism)) (PP (IN at) (NP (DT any) (VBN given) (NN time)))))))))) (. .)))
Metabolism is the sum total of all the chemical reactions occurring in an organism at any given time.
(ROOT (S (NP (NP (DT The) (NN sum)) (PP (IN of) (NP (NP (DT all) (JJ chemical) (NNS reactions)) (SBAR (WHNP (WDT that)) (S (VP (VBP take) (NP (NN place)) (PP (IN within) (NP (DT an) (NN organism))))))))) (VP (VBZ is) (VP (VBN known) (PP (IN as) (NP (NN metabolism))))) (. .)))
The sum of all chemical reactions that take place within an organism is known as metabolism.