Editing Cryptomonas (section)

== Cell structure ==
[[File:Cryptomonas platyuris - 160x (13286242253).jpg|thumb|Cryptomonas platyuris]]
Organisms are asymmetric with a transparent [[Cell membrane|membrane]] on the outside.<ref name=":1" /> The membrane is not ciliated.<ref name=":0" /> ''Cryptomonas'' cells are fairly large; they average about 40 micrometers in size and often take the shape of an oval or ovoid.<ref name=":3" /> There are two [[flagella]] present, yet the two flagella are not equally sized.<ref name=":0" /> One is shorter and curled and the other one is longer and straight.<ref name=":0" /> The two flagella are fixed to the cell by four unique [[microtubule|microtubular]] roots.<ref name=":0" /><ref name=":4">{{Cite journal|last=Roberts|first=Keith R.|date=1984-12-01|title=Structure and Significance of the Cryptomonad Flagellar Apparatus. I. Cryptomonas Ovata (cryptophyta)1|journal=Journal of Phycology|language=en|volume=20|issue=4|pages=590–599|doi=10.1111/j.0022-3646.1984.00590.x|s2cid=84268839|issn=1529-8817}}</ref> In addition, the flagella are lined with small hairs that allow for better movement.<ref name=":1" /> There are also [[contractile vacuole]]s that control the flow of water in and out.<ref name=":0" />

Two boat-shaped plastids are observed in the cells.<ref name=":1" /> In a secondary endosymbiosis event, the [[phagotroph]]ic ancestor of the ''Cryptomonas'' presumably captured a red alga and reduced it to a complex plastid with four envelope membranes.<ref name=":1" /> The [[phycobilisome]]s of the former red algae were reduced until only [[phycoerythrin]] remained.<ref name=":3" /> [[Phycoerythrobilin]], a type of red [[phycobilin]] pigment, is a [[chromophore]] discovered in cyanobacteria, chloroplasts of red algae and some Cryptomonads.<ref name=":3" /> Phycoerythrobilin is present in the [[phycobiliprotein]] phycoerythrin, the terminal acceptor of energy during the process of photosynthesis.<ref>{{Cite journal|last1=Chapman|first1=David J.|last2=Cole|first2=W. J.|last3=Siegelman|first3=Harold W.|date=1967-11-01|title=Structure of phycoerythrobilin|journal=Journal of the American Chemical Society|volume=89|issue=23|pages=5976–5977|doi=10.1021/ja00999a058|issn=0002-7863}}</ref> The phycoerythrin was translocated into the [[thylakoid]] lumen with its chromophore composition altered; subsequently, phycobiliproteins with at least seven different absorption spectra evolved.<ref name=":3" /> ''Cryptomonas'' is distinguished by the purple phycoerythrin 566 as an accessory pigment, which gives the organisms a brownish color in appearance.<ref name=":1" />