The Biggest Biological Distinction—Prokaryotes and Eukaryotes

All cells contain DNA. The total DNA of a cell is called the genome. Individual units of heredity, controlling individual traits by coding for a functional protein or RNA, are genes. 

The main difference between prokaryotic and eukaryotic cells is the existence of organelles, especially the nucleus, in eukaryotes. An organelle is a part of the cell that has a distinct function it is surroimded by its own membrane within the cell. In contrast, the structure of a prokaryotic cell is relatively simple, lacking membrane-enclosed organelles. Like a eukaryotic cell, however, a prokaryotic cell has a cell membrane, or plasma membrane, separating it from the outside world. The plasma membrane is the only membrane found in the prokaryotic cell. In both prokaryotes and eukaryotes, the cell membrane consists of a double layer (bilayer) of lipid molecules with a variety of proteins embedded in it. 

Nucleus No definite nucleus DNA present but not separate from rest of cell Present 

Cell membrane (plasma membrane) Present Present 

Mitochondria None enzymes for oxidation reactions located on plasma membrane Present 

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