Looking at a cell under a microscope you notice that it is a prokaryote how do you know

Looking at a cell under a microscope you notice that it is a prokaryote.  how do you know ?

It can be found that it is a prokaryote because it has no nucleus. They lack a 'true' nucleus that is membrane bound. Prokaryotes also lack mitochondria and chloroplasts. These are all single-celled organisms, most of which are known as bacteria.