Editing Chloroplast (section)

==== Cryptophytes ====
{{See also|Cryptomonad}}
[[File:CSIRO ScienceImage 6743 SEM Cryptophyte.jpg|thumb|Cryptophytes under [[Scanning electron microscope|SEM]].]]

[[Cryptomonad|Cryptophytes]], or cryptomonads, are a group of algae that contain a red-algal derived chloroplast. Cryptophyte chloroplasts contain a [[nucleomorph]] that superficially resembles that of the [[chlorarachniophytes]].<ref name="Keeling-2004" /> Cryptophyte chloroplasts have four membranes. The outermost membrane is continuous with the [[rough endoplasmic reticulum]]. They synthesize ordinary [[starch]], which is stored in granules found in the periplastid space—outside the original double membrane, in the place that corresponds to the ancestral red alga's cytoplasm. Inside cryptophyte chloroplasts is a [[pyrenoid]] and [[thylakoid]]s in stacks of two.<ref name="Kim-2009" /> Cryptophyte chloroplasts do not have [[phycobilisome]]s,<ref name="Kim-2009" /> but they do have [[Phycobilin|phycobilin pigments]] which they keep in the thylakoid space, rather than anchored on the outside of their thylakoid membranes.<ref name="Kim-2009" /><ref name="Keeling-2004" />

Cryptophytes may have played a key role in the spreading of red algal based chloroplasts.<ref>{{Cite thesis|last=Toledo|first=Rafael Isaac Ponce| name-list-style=vanc |title=Origins and early evolution of photosynthetic eukaryotes|date=5 March 2018|publisher=Université Paris-Saclay|url=https://tel.archives-ouvertes.fr/tel-01760725|language=en}}</ref><ref>{{cite journal | vauthors=Bodył A | title=Did some red alga-derived plastids evolve via kleptoplastidy? A hypothesis | journal=Biological Reviews of the Cambridge Philosophical Society | volume=93 | issue=1 | pages=201–222 | date=February 2018 | pmid=28544184 | doi=10.1111/brv.12340 | s2cid=24613863 }}</ref>