( Prokaryotes ( ( ( ( lack ( ( ( a nucleus ) and ) ( other ( membrane-bound organelles ) ) ) ) , ) ( although ( they ( ( ( have ( circular DNA ) ) and ) ribosomes ) ) ) ) . ) )
(ROOT (S (NP (NNS Prokaryotes)) (VP (VBP lack) (NP (NP (DT a) (NN nucleus)) (CC and) (NP (JJ other) (JJ membrane-bound) (NNS organelles))) (, ,) (SBAR (IN although) (S (NP (PRP they)) (VP (VP (VBP have) (NP (JJ circular) (NN DNA))) (CC and) (VP (VBZ ribosomes)))))) (. .)))
Prokaryotes lack a nucleus and other membrane-bound organelles, although they have circular DNA and ribosomes.
(ROOT (S (NP (NNS Prokaryotes)) (VP (VBP are) (NP (NN unicellular) (NNS organisms)) (SBAR (IN that) (S (NP (NN lack) (NNS organelles)) (VP (VBN surrounded) (PP (IN by) (NP (NNS membranes))))))) (. .)))
Prokaryotes are unicellular organisms that lack organelles surrounded by membranes.