Biology Marking Period 2 Test Practice

Distinguishing prokaryotic from eukaryotic cells comes down to the presence or absence of a nucleus and other membrane-bound compartments. Prokaryotes keep their DNA in a nucleoid region that isn’t enclosed by a membrane and generally lack membrane-bound organelles. They do have essential features like a cell membrane and ribosomes, but no internal compartments like mitochondria or chloroplasts.

In contrast, eukaryotes organize their internal space with a nucleus that houses their DNA, plus many membrane-bound organelles such as mitochondria, endoplasmic reticulum, Golgi apparatus, and, in plants and some protists, chloroplasts. This compartmentalization supports specialized, coordinated functions inside the cell.

So the key distinction is that prokaryotes lack a nucleus and membrane-bound organelles, while eukaryotes have both.