( ( Extracellular ( Structures ( Many prokaryotes ) ) ) ( ( ( have ( ( ( ( an ( extra layer ) ) , ) ( called ( a capsule ) ) ) , ) ) ( outside ( the ( cell wall ) ) ) ) . ) )
(ROOT (S (NP (NNP Extracellular) (NNP Structures) (JJ Many) (NNS prokaryotes)) (VP (VBP have) (NP (NP (DT an) (JJ extra) (NN layer)) (, ,) (VP (VBN called) (NP (DT a) (NN capsule))) (, ,)) (PP (IN outside) (NP (DT the) (NN cell) (NN wall)))) (. .)))
Extracellular Structures   Many prokaryotes have an extra layer, called a capsule, outside the cell wall.
(ROOT (S (NP (DT The) (NN capsule)) (VP (VBZ is) (NP (NP (DT the) (NN layer)) (PP (IN outside) (NP (NP (DT the) (NN cell) (NN wall)) (PP (IN in) (NP (DT a) (NN prokaryote))))))) (. .)))
The capsule is the layer outside the cell wall in a prokaryote.