( Prokaryotes ( ( are ( ( ( single-celled organisms ) ( that ( ( ( lack ( a ( membrane-bound nucleus ) ) ) and ) ( usually ( lack ( membrane-bound organelles ) ) ) ) ) ) ( -LRB- ( ( ( ( ( mitochondria , ) chloroplasts ) ; ) ( ( ( see cell ) , ) ( in biology ) ) ) -RRB- ) ) ) ) . ) )
(ROOT (S (NP (NNS Prokaryotes)) (VP (VBP are) (NP (NP (NP (JJ single-celled) (NNS organisms)) (SBAR (WHNP (WDT that)) (S (VP (VP (VBP lack) (NP (DT a) (JJ membrane-bound) (NN nucleus))) (CC and) (VP (ADVP (RB usually)) (VBP lack) (NP (JJ membrane-bound) (NNS organelles))))))) (PRN (-LRB- -LRB-) (S (NP (NP (NN mitochondria)) (, ,) (NP (NNS chloroplasts)) (, ;)) (VP (VBP see) (NP (NN cell)) (, ,) (PP (IN in) (NP (NN biology))))) (-RRB- -RRB-)))) (. .)))
Prokaryotes are single-celled organisms that lack a membrane-bound nucleus and usually lack membrane-bound organelles (mitochondria, chloroplasts; see cell, in biology).
(ROOT (S (NP (NP (JJ Prokaryotic) (NNS cells) (POS ')) (NNS organelles)) (ADVP (RB because) (RB not)) (VP (VBD membrane-bound)) (. .)))