( ( ( ( ( ( occurs ( when ( ( the ribosome ) ( ( reaches ( the ( stop codon ) ) ) ( on ( ( ( the ( messenger ( RNA molecule ) ) ) and ) ( the polypeptide ) ) ) ) ) ) ) ( , ( ( the messenger ) RNA ) ) ) , ) and ) ( ( the ( transfer ( RNA molecule ) ) ) ( are ( released ( from ( the ribosome ) ) ) ) ) ) . )
(ROOT (S (S (S (VP (VBZ occurs) (SBAR (WHADVP (WRB when)) (S (NP (DT the) (NN ribosome)) (VP (VBZ reaches) (NP (DT the) (NN stop) (NN codon)) (PP (IN on) (NP (NP (DT the) (NNP messenger) (NNP RNA) (NN molecule)) (CC and) (NP (DT the) (NN polypeptide))))))))) (, ,) (NP (DT the) (NN messenger)) (VP (VBZ RNA))) (, ,) (CC and) (S (NP (DT the) (NN transfer) (NNP RNA) (NN molecule)) (VP (VBP are) (VP (VBN released) (PP (IN from) (NP (DT the) (NN ribosome)))))) (. .)))
occurs when the ribosome reaches the stop codon on the messenger RNA molecule and the polypeptide, the messenger RNA, and the transfer RNA molecule are released from the ribosome.
(ROOT (S (SBAR (WHADVP (WRB When)) (S (NP (NP (DT a) (NN chain)) (PP (IN of) (NP (JJ amino) (NNS acids)))) (VP (VBZ reaches) (NP (DT a) (NN stop) (NN codon))))) (, ,) (VP (VBN released) (PP (IN from) (NP (DT the) (NN ribosome)))) (. .)))