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