Eukaryotic Evolution https://www.youtube.com/watch?v=9i7kAt97 XYU

2.3 - Eukaryotic Evolution Initially, there were only prokaryotes on Earth Eukaryotic evolution can be explained by a theory called endosymbiosis ENDOSYMBIOSIS: a symbiotic relationship between two or more prokaryotic cells 1) one cell engulfs (host cell) a different type 2) engulfed cell (endosymbioont) survives and becomes an integral part of the engulfing cell

Possible “engulfed” components 1) Chloroplast 2) Mitochondrion They have remained because they are both essential

Mitochondrion Most likely was an aerobic bacterium It was engulfed by a prokaryote It did not get destroyed Provided a means to extract energy from sugar

Chloroplast Most likely was a cyanobacterium It was engulfed by a prokaryote It did not get destroyed Provided a means to convert solar energy into sugar

Evidence to support this theory Mitochondria and Chloroplastas have the following in common with prokaryotes: 1) it has its own circular DNA! –Chloroplasts have very similar genes to cyanobacteria 2) it has a membrane similar to the structure of prokaryotes, since the membrane remained after the prokaryotic cell engulfed it. 3) undergoes binary fission to replicate organelles

ENDOSYMBIOSIS

HWK Pg. 71 # 4, 8,11,