( Nucleotides ( ( are ( composed ( of ( ( ( ( ( ( a ( phosphate group ) ) , ) ( a sugar ) ) ( -LRB- ( ( ( ( ( ribose ( in RNA ) ) , ) and ) ( deoxyribose ( in DNA ) ) ) -RRB- ) ) ) and ) ( ( a base ) ( which ( marks ( ( the ( specific difference ) ) ( among nucleotides ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NNS Nucleotides)) (VP (VBP are) (VP (VBN composed) (PP (IN of) (NP (NP (NP (DT a) (JJ phosphate) (NN group)) (, ,) (NP (DT a) (NN sugar)) (PRN (-LRB- -LRB-) (S (VP (VP (VB ribose) (PP (IN in) (NP (NNP RNA)))) (, ,) (CC and) (VP (VB deoxyribose) (PP (IN in) (NP (NNP DNA)))))) (-RRB- -RRB-))) (CC and) (NP (NP (DT a) (NN base)) (SBAR (WHNP (WDT which)) (S (VP (VBZ marks) (NP (NP (DT the) (JJ specific) (NN difference)) (PP (IN among) (NP (NNS nucleotides)))))))))))) (. .)))
Nucleotides are composed of a phosphate group, a sugar (ribose in RNA, and deoxyribose in DNA) and a base which marks the  specific difference among nucleotides.
(ROOT (S (NP (JJ Phosphate) (NNS groups)) (VP (VBP are) (VP (VBN found) (PP (IN within) (NP (NNS phospholipids) (CC and) (NNS nucleotides))))) (. .)))