Eukaryote: Any organism whose cells contain a nucleus and other structures (organelles) enclosed within membranes. Includes everything except bacteria.
Prokaryote: Single-celled organisms and lack a membrane-bound nucleus, mitochondria, or any other membrane-bound organelles. Prokaryotes are all bacteria and they can live in a wide variety of environments.
Similarities: Both have ribosomes, DNA, cytoplasms, and a cell membrane. Some also have flagellum. Both also have glycocalyx, or glycoprotein. (Think the slime on the outside of a fish) In eukaryotes, it is present in some cells that lack a cell wall and in prokaryotes, it is present as a capsule or slime layer.
Differences: Prokaryotes are the more simplistic, less complex ancestors of eukaryotes and as such are smaller in size (bigger than a virus but smaller than an amoeba) and more notably, lack a nucleus. Their DNA floats around in the cell, and while it is clumped up, it is not inside of a nucleus. Prokaryotes do not usually have any organelles, unlike eukaryotes. They will probably have ribosomes inside of their cells, but ribosomes are not technically considered organelles. Their chromosomal structure is different than that of eukaryotes (see diagram below).
Eukaryote examples:
- Amoeba
- Paramecium
- Euglena
Prokaryote examples: (all bacteria and cyanobacteria)
- E.coli
- Lactobacillus
- Salmonella
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