Can the sizes overlap in some bacterial species? My science teacher claims so. My research says the opposite. Can someone confirm?

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    $\begingroup$ Overlap not even uncommon. Compare this Anabaena (Cyanobacteria) image and Chlorella (green alga) image. Many of the eukaryotic planktonic algae overlaps with size of cyanobacteria. $\endgroup$ Jan 19, 2017 at 19:44
  • $\begingroup$ You should really unaccept the answer by Radek Martinez and change it to Remi.b's answer. The former is both unhelpful and simply not correct, while the latter gives specific examples of its point. $\endgroup$
    – Harris
    Jan 19, 2017 at 20:17

1 Answer 1


Prasinophytes are the smallest known eukaryotes. They are around 0.5 µm in diameter.

Thiomargarita namibiensis is the largest known prokaryote. They are around 100-300 µm in diameter.

So, yes some prokaryotes are much larger (up to about 500 times larger) than some eukaryotes.

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    $\begingroup$ To add to it, Pandoravirus, a virus, is about 1 µm by 0.5 µm. So not only can some prokaryotes be larger than some eukaryotes, some viruses are larger than some eukaryotes. $\endgroup$
    – R.M.
    Jan 20, 2017 at 18:23

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