Prasinococcus have a firm
cell wall lacking
scales and also lack
flagella. The mitochondrial lobe and
chloroplast outer membrane both protrude into the
pyrenoid matrix which is considered characteristic of the genus. The cell wall has a protruding circular collar which is surrounded by holes which penetrate the cell wall. Its method of
asexual reproduction is also considered characteristic - after cell division one daughter cell remains within the original cell wall while the other is extruded. The most notable feature of
P. capsulatus morphology is its large capsule composed of an exo-
polysaccharide which has been dubbed "
capsulan". Capsulan is thought to be synthesised in the
Golgi and then secreted through the decapore (a specialised circle of 10 pores through the
cell wall). After exiting the decapore capsulan becomes visible and it is thought that it cross links with
divalent ions in the seawater. Research is currently underway to find potential applications for capsulan and how to maximise its production. The capsule's function is not clearly defined but various explanations have been suggested. One is that it offers protection to newly divided cells which lack a thick cell wall, another is that it provides a template for daughter cells to synthesise their new cell wall. The capsule may also interfere with filter feeding, thus reducing predation. In similar species, capsules have been noted for their
antibacterial properties and a conspicuous lack of
bacteria as well as
viral particles in impure samples of
P. capsulatus has been observed. The
pigments of
Prasinococcus include chlorophylls a and b, prasinoxanthin, Mg 2, 4-diviriylphaeoporphyrin a5 monomethyl ester (Mg 2, 4-D) and 5, 6-epoxy-3, 3′-dihydroxy-5, 6, 7′, 8′-tetrahydro-β-ε-caroten-11′ and 19-olide (uriolide). ==Reproduction==