Prokaryotic organisms are mostly unicellular and much simpler in form and function than eukaryotic cells. Plants and animals have eukaryotic cells to carry out the complicated metabolic functions required to stay alive. Prokaryotic cells are much smaller, they don’t have any membrane bound organelles; parts enclosed in a separate sack and their DNA is in a very different form than eukaryotic cells. Prokaryotes have a central darker region in which a nucleoid is contained: a circular DNA and several smaller DNA bits called plasmids.

There is strong evidence to support that the mitochondria and chloroplasts in eukaryotic cells descended from independent prokaryotic cells. Often prokaryotes have a depression in their outer membrane that strongly resembles the cristae inside mitochondria. In addition, mitochondria have their own DNA that encodes proteins that they need to perform cellular respiration; this is their main function in the cell. Cellular respiration entails taking glucose and breaking it into molecules that provide energy to the cell; they are the digesters. Like prokaryotes, mitochondrial DNA is a single ring, like prokaryotic DNA, and they both have their own simple ribosomes that manufacture protein.

With that small digression aside, let me give you some examples of prokaryotes and eukaryotes. Prokaryotes include all of the wonderfully strong and adaptable bacteria that cause humans so much grief like Staphylococcus aureus and Escheria coli. Eukaryotes, are you, me, the dog, our house plants, the food we eat; the list goes on and on.

In summary, prokaryotes, have no membrane bound organelles, they have a ring shaped DNA and are much smaller and simpler in structure. Eukaryotes have a nucleus and membrane bound organelles. They are much larger and more complex. Their DNA is in many long strands.