Differences Between Prokaryote and Eukaryote Cells FeatureProkaryoteEukaryote Size small, mean diameter 0.5 - 5  m Up to 40  m common Genetic material Contained in nucleoid and plasmids DNA associated with proteins to form a chromosome, found within a nucleus Organelles Few present and none surrounded by a plasma membrane Many organelles; Some with double membranes e.g.