( ( Each circle ) ( ( represents ( ( ( an ( alpha carbon ) ) ( in one ) ) ( of ( ( the ( two ( polypeptide chains ) ) ) ( that ( ( make up ) ( this protein ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (DT Each) (NN circle)) (VP (VBZ represents) (NP (NP (DT an) (JJ alpha) (NN carbon)) (PP (IN in) (NP (CD one))) (PP (IN of) (NP (NP (DT the) (CD two) (JJ polypeptide) (NNS chains)) (SBAR (WHNP (WDT that)) (S (VP (VBP make) (PRT (RP up)) (NP (DT this) (NN protein))))))))) (. .)))
Each circle represents an alpha carbon in one of the two polypeptide chains that make up this protein.
(ROOT (S (NP (NNP Insulin)) (VP (VBZ is) (VP (VBN made) (PRT (RP up)) (PP (IN of) (NP (CD two) (JJ polypeptide) (NNS chains))))) (. .)))