( ( ( ( ( ( ( Nearly all ) reactions ) ( that ( occur ( in ( living cells ) ) ) ) ) ( require ( catalysts ( called enzymes ) ) ) ) - ) ( ( without them ) ( , ( life ( would ( be impossible ) ) ) ) ) ) . )
(ROOT (S (S (NP (NP (QP (RB Nearly) (DT all)) (NNS reactions)) (SBAR (WHNP (WDT that)) (S (VP (VBP occur) (PP (IN in) (NP (VBG living) (NNS cells))))))) (VP (VBP require) (SBAR (S (NP (NNS catalysts)) (VP (VBD called) (NP (NNS enzymes))))))) (: -) (S (PP (IN without) (NP (PRP them))) (, ,) (NP (NN life)) (VP (MD would) (VP (VB be) (ADJP (JJ impossible))))) (. .)))
Nearly all reactions that occur in living cells require catalysts called enzymes- without them, life would be impossible.
(ROOT (S (NP (PRP You)) (VP (VBP call) (NP (NP (NNS catalysts)) (SBAR (WHNP (WDT that)) (S (VP (VBP are) (VP (VBN found) (ADVP (RB inside)) (PP (IN of) (S (VP (VBG living) (NP (NNS things) (NNS enzymes))))))))))) (. .)))