Diagrams of endosymbiotic cells
Symplified diagrams of serial phagocytosis of purple and photosynthetic bacteria, leading to primary* endosymbiotic accommodations. 
(adapted from)
1. ancestral prokaryote, undergoes
2. infoldings of plasma membrane, which permits
3. development of nuclear membrane and endomembranous system
4. engulfment of aerobic heterotrophic prokaryotes, generates
5. ancestral heterotrophic eukaryote with mitochondria.
(adapted from)1. ancestral prokaryote, undergoes
2. infoldings of plasma membrane, which permits
3. development of nuclear membrane and endomembranous system
4. engulfment of aerobic heterotrophic prokaryotes, generates
5. ancestral heterotrophic eukaryote with mitochondria.
~~~
Next, acccording to SET,
an ancestral heterotropic eukaryote (5) undergoes
6. serial engulfment of photosynthetic prokaryotes, which generates
7. ancestral photosynthetic eukaryote with plastids.
Schematic in FFT Article Protist Images: Endosymbiosis and Parasitism Hatena
*Secondary endosymbiosis is engulfment by a eukaryotic cell of another eukaryote that already possesses endosymbiotic organelles derived from primary endosymbiosis. Similarly, acquisitions may be tertiary. The eukaryotic crown group Alveolata has a particularly complex history of plastid acquisition.
More images: Site with good diagrams tems & drop-down menu of endosymbiosis and chloroplasts : diagram of plastid diversity : diagram ~ endosymbiotic formation of algal groups :
1 Glossary:
"The majority vision today is more that of a common ancestor resembling either bacteria or archaea, and for some , that of a creature intermediate between prokaryotes (cells without nuclei) and eukaryotes (cells with nuclei)." Patrick Forterre
http://www-archbac.u-psud.fr/Meetings/LesTreilles/LesTreilles_e.html
Progenote: Carl Woese proposed the term 'progenote' in 1977. However, the notion of 'progenote' is associated with the conception of a particularly primitive ancestor.
Cenanster: The term cenancestor was proposed by Fitch in 1987, and derives from the Greek root 'cen, meaning together.
Last Common Ancestor: This term could be applied anywhere within a phylogenetic cladogram to indicate the root organism of a phyletic group.
LUCA: Last Universal Common Ancestor is a compromise between LUA and LCA.
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