( ( These nitrogenous ) ( ( bases ( ( hydrogen bond ) ( between ( ( opposing ( DNA strands ) ) ( to ( form ( ( ( ( the rungs ) ( of ( ( ( the ( `` ( twisted ( ladder '' ) ) ) ) or ) ( ( double helix ) ( of DNA ) ) ) ) ) or ) ( ( a ( biological catalyst ) ) ( that ( is ( found ( in ( the nucleotides ) ) ) ) ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (DT These) (NNS nitrogenous)) (VP (VBZ bases) (NP (NP (NN hydrogen) (NN bond)) (PP (IN between) (S (VP (VBG opposing) (NP (NN DNA) (NNS strands)) (S (VP (TO to) (VP (VB form) (NP (NP (NP (DT the) (NNS rungs)) (PP (IN of) (NP (NP (DT the) (`` ``) (JJ twisted) (NN ladder) ('' '')) (CC or) (NP (NP (JJ double) (NN helix)) (PP (IN of) (NP (NNP DNA))))))) (CC or) (NP (NP (DT a) (JJ biological) (NN catalyst)) (SBAR (WHNP (WDT that)) (S (VP (VBZ is) (VP (VBN found) (PP (IN in) (NP (DT the) (NNS nucleotides))))))))))))))))) (. .)))
These nitrogenous bases hydrogen bond between opposing DNA strands to form the rungs of the "twisted ladder" or double helix of DNA or a biological catalyst that is found in the nucleotides.
(ROOT (S (NP (DT The) (JJ double) (NN helix) (NN dna) (NN shape)) (VP (VBZ forms) (SBAR (WHADVP (WRB when)) (S (NP (DT the) (CD two) (JJ nucleotide) (NNS chains)) (VP (VB wrap) (PRT (RP around)) (NP (DT the) (JJ same) (NNS axis)))))) (. .)))